Antibiotic resistance threatens provision of healthcare and livestock production worldwide with predicted negative socioeconomic impact. Antibiotic stewardship can be considered of importance to people living in rural communities, many of which depend on agriculture as a source of food and income and rely on antibiotics to control infectious diseases in livestock. Consequently, there is a need for clarity of the structure of antibiotic value chains to understand the complexity of antibiotic production and distribution in community settings as this will facilitate the development of effective policies and interventions. We used a value chain approach to investigate how relationships, behaviours, and influences are established during antibiotic distribution. Interviews were conducted with key informants (n = 17), value chain stakeholders (n = 22), and livestock keeping households (n = 36) in Kolkata, and two rural sites in West Bengal, India. Value chain mapping and an assessment of power dynamics, using manifest content analysis, were conducted to investigate antibiotic distribution and identify entry points for antibiotic stewardship. The flow of antibiotics from manufacturer to stockists is described and mapped and two local level maps showing distribution to final consumers presented. The maps illustrate that antibiotic distribution occurred through numerous formal and informal routes, many of which circumvent antibiotic use legislation. This was partly due to limited institutional power of the public sector to govern value chain activities. A ‘veterinary service lacuna’ existed resulting in livestock keepers having higher reliance on private and informal providers, who often lacked legal mandates to prescribe and dispense antibiotics. The illegitimacy of many antibiotic prescribers blocked access to formal training who instead relied on mimicking the behaviour of more experienced prescribers–who also lacked access to stewardship guidelines. We argue that limited institutional power to enforce existing antibiotic legislation and guide antibiotic usage and major gaps in livestock healthcare services make attempts to curb informal prescribing unsustainable. Alternative options could include addressing public sector deficits, with respect to both healthcare services and antibiotic provision, and by providing resources such as locally relevant antibiotic guidelines to all antibiotic prescribers. In addition, legitimacy of informal prescribers could be revised, which may allow formation of associations or groups to incentivise good antibiotic practices. Antibiotic stewardship is an important tool to mitigate the effects of antibiotic resistance (ABR) , 2, whicHistorically, antibiotics have been used during animal production to protect against and treat disease and to promote livestock growth. While recent trends for Asia, the Far East and Oceania have shown a decrease in overall usage per kilogram of animal biomass (230mg/kg in 2016 to 150mg/kg in 2018) 36% of countries in this region still report the use of antibiotics for growth promotion . India iBy Indian regulations, antibiotics can only be sold on the prescription of a qualified medical practitioner, but their over the counter sales  continue in both human and animal health, and by providers who do not have formal professional qualifications –25. Thiswww.oasisamr.com) that investigates the patterns and drivers of antibiotic use in human and livestock healthcare in rural community settings in West Bengal.To date, there have been few documented attempts in India or other LMICs to implement antibiotic stewardship at a national level in livestock , 29, andFor this study, we use a value chain analysis approach which assesses the systems in which commodities are produced and exchanged, and attempts to detail the often complex relationships which occur within and between nodes–the places or actors—along the value chain –33. ConsWest Bengal was chosen as a case study as it is one of India’s major agricultural states—milk, egg, and meat contribute to 3%, 8%, and 10% of national production respectively –where ruTwo differing Gram Panchayats [a village administrative unit] in South 24 Parganas district, were chosen from those known to have numerous medical informal providers in the area and in a purposive manner based on the number of households keeping livestock (50% and 90% of households reported to keep livestock in sites 1 and 2 respectively ) and theInterviews were conducted with key informants –individuals with anticipated high-level knowledge of the entire antibiotic value chain, antibiotic value chain stakeholders–individuals who were questioned primarily about their own practice, , and with livestock keeping households . Interviews took place in Kolkata, and the two study sites between June 2019 and January 2020 ; Fig 1.a priori interview guides for the semi-structured in-depth interviews. These guides were designed to differentiate the types of stakeholders involved in the antibiotic value chain, their roles, inter-actor relationships, and links between livestock and human antibiotic value chains. Where possible interviewees were asked to provide information about which antibiotics they most commonly dealt with, and their perceptions of ABR. When participants were unfamiliar with the term ‘antibiotics’, for example some of the livestock keepers, we asked broader questions about treatments and general medicines to delineate their knowledge. Complete interview guides are provided in Interviewees were selected using purposive convenience sampling using a network of partners in the project and a snowballing technique with the aim of capturing perspectives from all actors operating in the value chain. In Site 1, an ex-village chief, teachers, and ex-government veterinarian were identified as key informants and interviewed to provide an overview of the area and to help identify livestock keepers and livestock healthcare providers. In Site-2, we followed the same process by interviewing a non-government organisation (NGO) veterinarian and veterinary and livestock development officers working for the public sector. In both sites, as many as possible of the identified stakeholders operating in the system were contacted and invited to participate in an interview. Households in both sites were selected to provide information on a range of livestock types  and production systems . Information gathered from a review of existing literature was used to generate Questions were open-ended to minimise interviewer confirmation bias and interviewee social desirability bias . InterviDuring each interview, key-informants and stakeholders were asked to help produce antibiotic flowchart diagrams by identifying and characterising all nodes and flows of antibiotics known to them. The characterisation of nodes was completed by prompting interviewees with questions relating to the differences in suppliers, clients and users of antibiotics, and how these nodes are connected. In addition, participants were asked to indicate where the major volume flows of antibiotics occurred. During household interviews, information was gathered about how drivers for choice of healthcare provider relates to the antibiotic value chain.Ethical approval for the study was obtained by Observational and Interventions Research Ethics Committee and MSc Research Ethics Committee of the London School of Hygiene and Tropical Medicine , the Institutional Animal Ethics Committee of West Bengal University of Animal and Fishery Sciences (Ref: IAEC/190(XVII)/B/1288, 19 March 2019), and the Social Sciences Research Ethical Review Board of the Royal Veterinary College . All participants involved in this study were provided with an information sheet prior to interview informing that their anonymised data could be used in research publications. Each participant was asked to provide their consent using a written consent form.Interviews conducted in English were transcribed by the primary author while interviews conducted in Bangla were translated and transcribed by a member of the local research team. Data extracted from the transcribed interviews were entered into QRS International NVivo (ver. 12.6.0.959) for data management. Transcripts were created using an intelligent verbatim method–a word for word account of the interview without inclusion of all grammatical errors, mistakes, and expressions of emotion .In the first part of the analysis we applied the heuristic principles of value chain analysis to map the chains and describe the value chain structure. Following the process indicated in Alarcon et al. , we idenPower analysis is critical in understanding how health-related policies lead to inequal access to health care and identify entry points to improve health outcomes particularly by marginalised populations . In our Investigation of power relationships in the value chain provides an opportunity to consider the way actors interact with unintended consequences–or externalities–resulting from chain activities, an area largely absent from early value chain governance literature–e.g., Gereffi et al. , Kaplinsmanifest approach, and are organised according to our study objectives and the power dynamic framework. Consequently, the interpretation of these descriptive findings occurs during our discussion. This is in contrast to other qualitative data analysis techniques, such as thematic analysis, which seek to provide explanation and interpretation through the act of generating themes . They will rather put their certificate on loan. So, if some moneyed man in village wants to start a chemist shop, he has to find a pharmacist in his locality, ‘why don’t you help me open my shop? I will give you 10,000 Rs or 20,000 Rs a month [approx. £100–200]’.” Pharmacology academics, Kolkata (KI-2-240919)Pharmacy and drug shop owners, not pharmacists, often dispensed antibiotics either over the counter or via an informal prescription written by livestock healthcare providers who lacked the legal mandate to do so, such as Pranibandhu and para-vets.The Drugs Control Office in the Gram Panchayats, who were responsible for enforcing medicine governance, including regulating the area’s 3,000 to 4,000 pharmacies, employed just five staff to conduct inspections. This lack of public sector enforcement capacity was coupled with concerns of corruption that further limited the effectiveness of inspections:“If there is a raid and the drug inspector asks, ‘where is your pharmacist?’ and the pharmacist is not there, which most of the time they are not, then the inspector can close the pharmacy. But the inspector will not, as immediately the inspector will be bribed. There is hardly any punishment in the public system. You can call it a kind of dishonesty or corruption.” Pharmacology academics, Kolkata (KI-2-240919)Consequently, commercially motivated actors were not obliged to conform to legislation designed to regulate, and potentially limit, their value chain activities.Lack of guidance regarding responsible and prudent antibiotic usage. We also consider the role of professional associations such as veterinary statutory bodies and training centres in ensuring responsible and prudent antibiotic use. Here, another example of limited institutional power was the lack of antibiotic usage guidelines. We did not observe any government-based antibiotic usage guidelines and the only guidelines noted were those created and supplied by the veterinarians in Site 2 working for the NGO and in the government centres concerning production of small-scale commercial poultry systems. These written guidelines advised poultry producers to use antibiotics prophylactically to prevent respiratory and diarrhoeal diseases, including fluoroquinolones which are classified as highest priority critically important antibiotics for human health:“From our institution one chart has been prepared from day one to day 35 [of poultry production]. Say from zero to four days tetracycline is used and from 22 to25 days another antibiotic, say enrofloxacin, is used for all the [birds] […] If any problem arises in that period then they use other antibiotics, say tylosin for respiratory tract infection.” Veterinarian, Site 2 (KI-1-130120)The evidence from these findings suggests that existing regulations to ensure biomedical expertise regarding rational antibiotic use are not implemented and enforced. Moreover, the only antibiotic use guideline available was commercially motivated. Therefore, users lacked information that enabled them to use antibiotic appropriately. In fact, the converse was true, the information available to them and which they followed was sometimes inappropriate.The ‘veterinary service lacuna’ creates opportunity for informal providers. In both study sites, livestock keepers only had access to a small number of veterinary medicine outlets–most of the pharmacies stocking veterinary medicines were in nearby towns rather than in the study sites. Furthermore, there was limited access to public veterinary services, with veterinary officers being stationed in local towns. This presented difficulties in accessing public livestock services, with livestock keepers citing the time and cost of getting to the block veterinary office as a barrier to access. Consequently, in both sites, livestock keepers received antibiotics through various livestock healthcare providers who lacked mandates to supply antibiotics to livestock, including human healthcare providers:“The [veterinary] doctor isn’t always available. But the people at the pharmacy are also doctors. We tell them I have a cow and it looks sick, give us some medicine.” Livestock keeper, Site 1 (LK-5-010719)While dual public-private practitioners—the Pranibandhu and Pranimitra- received no formal training on antibiotic use, para-vets working in site 2 received basic information on antibiotic use from the NGO. However, none of these stakeholders were legally allowed to prescribe antibiotics . After t“We appeal in the high court. We are here for so long, we must be given some permanent post. An order was given once [by the government] that we should be permanent. But final order is yet to be released, the dates are pending. We Pranibandhu, are under the government but we don’t get any salary from them.” Pranibandhu, Site 1 (SH-5-191119)Para-vets too, while retaining an association with the NGO training centre, receive no benefits from the government. The lack of legitimacy for these actors represents two problems. Firstly, livestock healthcare providers primarily generate income through medicine sales- including antibiotics- as described by this Pranibandhu:“The training we received as Pranibandhu has been on artificial insemination. We weren’t asked to prescribe medication. But if we did just that we won’t make enough money, so we, on our own, have learnt how to use antibiotics from other veterinary doctors.” Pranibandhu, Site 1 (SH-5-110719)Secondly, a void in prescribing control exists. The full gamut of prescribing habits cannot be monitored if the state refuses to acknowledge the role of informal providers in safeguarding animal health.In summary, the lack of public and formal veterinarians encouraged informal livestock healthcare providers to emerge, most of whom prescribe antibiotics without the mandate to do so. As they are not recognised as formal antibiotic prescribers, they are unable to access formal training on appropriate antibiotic use and operate in a context where prescribing antibiotics is a tool to earn income and remains unmonitored by the state.Bargaining power is described as a coercive type of power, occurring when a dominant actor or firm can coerce others into doing something that they may otherwise not do .Pharmaceutical and wholesalers use incentives to promote antibiotic use. Medical representatives working for pharmaceutical and wholesale companies can be considered to exercise bargaining power for their companies over other value chain stakeholders. Here, representatives use incentives, providing stockists and retailers with access to credit, discounts and gifts for bulk purchase, promotional and educational schemes, and their ability to be highly mobile within the physical space of the value chain, to influence purchasers to buy certain types and volumes of antibiotics. Furthermore, some medical representatives interact with livestock healthcare providers and livestock keepers directly to promote antibiotic use. One para-vet discussed his frequent interaction with medical representatives:“[I] have the phone number of medical representatives also, they sometimes come and tell [me] that this new medicine works better in this condition. And I used that [antibiotic] in the field, if it works I use it afterwards.” Para-vet, Site 2 (SH-1-130120)This again highlights the commercial incentives for antibiotic use. Medical representatives have opportunity to generate additional profit for their companies by promoting antibiotic use.When considering the type of demonstrative power operating in the value chain, we look to actors who are influencing others by establishing standards.Livestock healthcare providers mimic others prescribing habits. We observed evidence of less experienced healthcare providers mimicking prescribing behaviour of more experienced providers–such as veterinarians–who exert demonstrative power by sharing their antibiotic practices within a local context:“We have learnt how to use antibiotics from other veterinary doctors. For example, we would accompany them during their visits and learn which antibiotics are used when. This is how we learnt it.” Pranibandhu, Site 1 (SH-5-110719)Some of these experienced veterinarians operating in the study sites were seen to be promoting antibiotic stewardship practices, and attempting to influence other livestock healthcare providers:“We are trying to make the para-vets aware in a refresher training programme that you have to wait for three days. After [this], if it is not getting better then you can consult [us] and use antibiotics.” Veterinarian, Site 2 (KI-1-130120)Similarly, one pharmaceutical representative discussed how they use their interactions with healthcare providers to disseminate information on medicine usage:“We are doing a lot of para-vet conferences and company visits. We are trying to educate [them] in our own way. Some protocols are there, E. coli mastitis, different types of mastitis. We are giving information; which types of drugs are most effective.” Pharmaceutical representative, Kolkata (KI-%-200120)However, as reported earlier (Section 3.2.1), we observed evidence of veterinarians developing and using antibiotic guidelines which contain practices deemed inappropriate–namely the prophylactic use of fluoroquinolones in poultry. Consequently, transfer of antibiotic use experience from more to less experienced, and formal to informal, healthcare providers may not always align with ideal antibiotic stewardship goals.These instances are examples of how livestock healthcare providers maintain a close relationship with other value chain actors within which information on antibiotic use is shared. While the relationships are not formalised, formal veterinarians and medical representatives express demonstrative power regarding common practices of antibiotic provision over other less experienced livestock healthcare providers.Here we look to the social norms and understandings which surround antibiotic use and resistance in the study, to–as Dallas et al.  describeWe observed varying levels of knowledge among our study participants concerning antibiotic use and resistance. Veterinarians and some medical representatives and livestock healthcare providers discussed concepts aligned with allopathic antibiotic stewardship such as spectrum of activity, diagnostic testing, and the negative consequences of antibiotic use such as side effects and resistance.The responses of several livestock healthcare providers indicated that they had learned about antibiotics through many years of experience. Both the positive and negative effects of antibiotic usage were discussed, including possible side effects in livestock such as poor growth or abortion:“Once I used sulpha drugs [such as the antibiotic sulfadiazine] for diarrhoea but then abortion happened. So, I stopped using sulpha drug in diarrhoea cases.” Para-vet, Site 2 (SH-1-130120)Among pharmacy and drug shop owners and attendants, knowledge of antibiotics was variable, with some being unable to correctly identify antibiotics, reflecting the lack of formal training these stakeholders had received, as most are not pharmacists. Similarly, livestock keepers’ knowledge was also varied; while some were able to name certain antibiotics and demonstrate understanding of how antibiotics should be used properly—for example by following advice to complete a course of treatment—others thought that antibiotics could be used to treat viruses or were unfamiliar with the word ‘antibiotic’. Of those unfamiliar with the term antibiotic, further questioning revealed that many livestock keepers referred to the pharmaceutical treatments given to their livestock in broad terms such as ‘medicines’, ‘tablets’, or ‘injections’.Antibiotics are considered essential for treating a range of conditions. What pervaded those stakeholders familiar with antibiotics was the close association antibiotics have with ‘modern’ medicine, with people talking about how antibiotics alleviate fear of bad outcomes and create confidence, and are therefore an integral part of healthcare:“If I am not using antibiotics in cows and goats, there is no confidence whether it will be cured or not. If I use antibiotic I am confident that the animal must get well. If I don’t use [antibiotics], it would feel bad in my mind.” Para-vet, Site 2 (SH-1-130120)“If a cow has a fever and I don’t use oxytetracycline, will that fever go down? I have to save [the cow]. Is there any way that without giving antibiotic the fever can be reduced? Is there any way the government of India [can] circulate [advice] among us?” Veterinary drug shop owner, Site 1 (SH-2-191119)In addition, both livestock healthcare providers and livestock keepers have experienced that antibiotics are effective healthcare tools to prevent and treat illness in animals. These personal experiences have reinforced the notion that antibiotics are powerful, and therefore desirable, in treating disease and boosting farm productivity:“In poultry it is very much necessary to use antibiotics, in case of animal [livestock] it is ok [not to], but in poultry, without antibiotic it is very hard to stop mortality. It is like that antibiotic has to be used every day.” Para-vet, Site 2 (SH-2-130120)“When symptoms like fever occur, and two or three days [have] passed but it does not go down, if you give antibiotics it is cured quickly.” Pranimitra, Site 2 (SH-3-150120)Consequently, social demand for antibiotics, whether appropriate or inappropriate, continues to be generated at the end of the value chain.While some value chain actors demonstrated knowledge of antibiotic use in line with allopathic ideas of stewardship, many had limited knowledge, and commercial incentives to generate profit and obligational incentives to satisfy desires for positive clinical outcomes, may thus override opportunities to limit antibiotic use.In summary, our power dynamic analysis demonstrates that the government currently lacks institutional power to influence value chain actors’ behaviours to use antibiotics appropriately. Pharmaceutical companies, wholesalers, and retailers motivated by profit generation face little interference from the state.Because of the limited public sector capacity to provide adequate number of veterinarians for rural livestock keepers, for-profit actors have emerged at the end of the value chain to meet the demand for livestock healthcare, yet currently lack legitimacy and access to training opportunities to improve antibiotic use practices. Furthermore, a lack of guidelines for responsible and prudent use compounds the influence of for-profit actors and prevents deviation from strong social norms which continue to associate antibiotics as the most efficacious and safe therapeutic option for many diseases. As such, commercial interests and pressure to prescribe may incentivise stakeholders to deviate from appropriate use.In this section, we discuss how the structure of the antibiotic value chain and the power relationships therein have implications for antibiotic stewardship in the study sites, with a summary provided in Our research shows that access to livestock healthcare and antibiotics exists within a pluralistic veterinary health system where public and private, and formal and informal antibiotic providers operate. This is similar to the provision of healthcare and antibiotics in the human health sector in India  and has Consequently, numerous actors seek opportunity to earn a living by filling this ‘veterinary service lacuna’. While many of the livestock healthcare providers are not legally allowed to prescribe antibiotics, the finding that this practice was widespread was consistent with other LMICs , and hasABR is a complex negative externality issue, affecting the lives and livelihoods of users themselves and others, and occurring with a time-lag: actions today do not have an immediate consequence. Thus, markets alone cannot incentivise value chain actors to control ABR. Consequently, the state and citizens must intervene. Public bodies—governments and regulators–need to be responsible for shaping value chain actors’ behaviours through regulations, enforcement and incentives so that they use antibiotics appropriately. However, citizen intervention is challenging when awareness and knowledge on the issue is lacking and people have commercial, livelihood, and/or health interests that go against antibiotic stewardship.Our research shows that the government’s influence–i.e., their institutional power–is lacking in three key aspects. Firstly, existing regulations regarding the licencing of antibiotic distributors  and qualification of antibiotic prescribers are not effectively enforced because of staff shortages, stakeholder’s vested interests, and the discrepancy between regulatory requirements and reality of limited access to qualified prescribers. For example, while retail legislation stipulated that pharmacies were operated by people with pharmacology training, this was rarely the case and consequently antibiotics were dispensed by non-pharmacists. Kotwani et al.  report sSecondly, we observed no proper guidelines for responsible and prudent use in the study sites. As a result, guidelines developed for profit driven actors such as those for commercial poultry production in Site 2 include the routine use of fluoroquinolone antibiotics for prophylaxis. This type of practice is deemed inappropriate by the Food and Agriculture Organization of the United Nations, the World Organisation for Animal Health, and the Indian National Action Plan on ABR , 63, 64.Thirdly, the public sector could not meet the demand for veterinary healthcare, which led to for-profit actors and informal healthcare professionals, both livestock and human, prescribing antibiotics to livestock. These actors, operating in an institutional power void, exercise their bargaining power to generate profit from antibiotic sales. For instance, pharmaceutical and wholesale companies employed representatives to conduct marketing for their products. While further research is needed to assess how profit margins vary across different antibiotics, and how this may influence prescribing decisions, Nguyen  highlighWhile we cannot assume that informal providers’ practices are worse than formal providers, their lack of formal training may increase the likelihood of this happening as inexperienced stakeholders were reliant on mimicking the prescribing patterns of other antibiotic users, an example of demonstrative power operating in the value chain. Indeed, there was substantial variation in the level of antibiotic training received by prescribers as discussed. Even when expertise was available through trained pharmacists, they were mostly absent from drug shops and therefore their knowledge was not transferred to antibiotic prescribers and users. This indicates the need to target antibiotic stewardship interventions to all prescribers–both formal and informal–as suggested by Gautham et al. .In our study sites antibiotics remain closely entangled with concepts of ‘modern’ medicine and continue to be used as first line treatment, often in cases where this may not be clinically necessary. This social norm of antibiotics being essential for the treatment of disease–an example of constitutive power operating in the value chain—has been reported by others: Pearson and Chandler  describeOur power analysis demonstrates that work is needed on multiple fronts of the power framework: not just strengthening institutional power, but also building constitutive and demonstrative power. Based on this evidence, our recommendation to improve antibiotic stewardship in West Bengal is twofold and looks beyond simply suggesting government increase their enforcement capacity, an action which could deliver real change but is likely to face significant economic barriers. Furthermore, given the lack of veterinary infrastructure, implementation and enforcement of existing antibiotic legislation could leave many livestock keepers without access to treatments, with negative consequences to livelihoods and animal health and welfare. Moreover, veterinarians too may have knowledge limitations which need to be addressed in their pre-service training.First, the public sector could develop treatment guidelines for the animal sector which are aligned with antibiotic stewardship goals and international standards . For livestock healthcare providers, deferring to alternative treatments or pricing structures which prioritise payment for services may alleviate this pressure. However, this may be more challenging when considering adoption of stewardship by pharmaceutical companies and medical representatives whose business models are focused on sales volumes. For commercial livestock, improvements in biosecurity and animal husbandry practices are needed to support production so that enterprises are not left vulnerable without antibiotics.Second, the dissemination of newly-developed guidelines and provision of training opportunities needs to include all veterinary healthcare providers–including informal antibiotic providers, thus urging the state to recognise their value as essential animal health care providers. However, providing legitimacy requires careful considerations and consultation with different stakeholders. In their work with the World Organisation for Animal Health, Cobbold et al.,  describeCurrently, literature linking value chain and power analysis to the development of effective interventions in livestock and healthcare sectors is lacking. In their report on ‘value chain development for decent work’, the International Labour Office set out a framework for value chain development , which iUsing a framework for value chain power development set out in Dallas et al.,  we hypotLimitations exist within this study. Qualitative research data may be biased because of hidden agendas, assumptions, and the etic lens of the research team; as researchers working on antibiotic use and stewardship we are biased towards the view that antibiotic reform is a worthwhile endeavour and in the public interest. Social desirability bias may have been introduced by those participants aware that their antibiotic practices may be inappropriate. Furthermore, the construction of ‘truth’ within our findings occurred through interactions between ourselves, translators, and those being interviewed i.e., a critical realist ontological position and it is possible that alternative ‘truths’ may exist. For example, basing our household selection criteria on livestock type and production system may have overlooked differences introduced by variation in participant gender, education level, and socioeconomic status. However, we sought to limit these potential issues by using non-leading open ended questions , gatheriDuring the study we also sought to question stakeholders about antibiotic quality. However, these questions proved challenging and the answers did not provide robust information to include in our analysis. Additionally, we anticipated discussion of antibiotic use would reveal more information regarding the social value of antibiotics to those using them. It is possible that this line of enquiry was hindered due to many of our questions focusing specifically on antibiotics rather than medicines in general, and the fact that many livestock keepers were not familiar with the term antibiotics. Consequently, additional study could involve detailed ethnographic work focusing on how interactions with medicines shape livestock keepers’ experiences of interacting with healthcare. Despite these limitations, our study provides a granular account of antibiotic distribution across the study sites and the power dynamics operating therein which could impact the development of antibiotic stewardship interventions.Further work to investigate antibiotic value chains could include additional exploration of how stakeholders interact with and consider substandard and falsified medicines, as this issue was outside the scope of our project but has been identified as a topic of interest in antibiotic stewardship, particularly in Asia, Africa, and Latin America , 72. QuaThis paper describes how antibiotic distribution to livestock in rural West Bengal occurs through numerous routes and nodes, both formal and informal, many of which circumvent legislation designed to control how antibiotics are governed. Given the current lack of enforcement capacity governing antibiotic distribution and the frequency of informal antibiotic prescribing that occurs in livestock healthcare, it is unlikely that attempts to mandate antibiotic prescribing alone will be viable stewardship options. Alternative options could include addressing public sector deficits, with respect to both service and antibiotic provision and by providing resources such as independent and locally relevant antibiotic guidelines. When disseminating these guidelines, all antibiotic prescribers—both formal and informal–should be included to increase the legitimacy of all livestock healthcare providers and the quality of antibiotic use in the value chain.By describing and analysing the antibiotic value chain and considering the various power dynamics operating therein, we identified several possible entry points for antibiotic stewardship. These entry points will need to be investigated in further detail, in consultation with value chain stakeholders, to ascertain the potential for related interventions to improve the quality of antibiotic use in the two study sites we investigated and in other similar resource scarce settings.S1 File(DOCX)Click here for additional data file.S2 File(DOCX)Click here for additional data file.S3 File(DOCX)Click here for additional data file.


It is not uncommon for patients to have a labeled allergy to antibiotics without thorough investigation of their adverse reactions. The adverse reactions described by some patients are not immune-mediated and these patients are incorrectly labeled as having an antibiotic allergy. As clinical testing for antibiotic allergy is expensive and time intensive, recent initiatives have successfully used patient interviewing to differentiate non-immune mediated reactions from true antibiotic allergies. We investigated the prevalence of patients with non-immune mediated reactions to antibiotics among patients with documented antibiotic allergy by using a standardized questionnaire in the outpatient setting.Patients with a documented antibiotic allergy were identified and recruited from 2 clinics located in the greater Chicagoland area. Subjects completed one standardized questionnaire regarding each of their previous adverse reaction to antibiotics. We then evaluated the questionnaire responses to extricate the non-immune-mediated adverse reactions. The full symptom classification can be found in Table 1 and Table 2.98 patients were recruited with a total of 159 antibiotic questionnaires completed. At the patient level, 18 individuals had no immune-mediated reactions despite antibiotic allergy labels: 18.37% . At the antibiotic level, 35 labels had corresponding clinical histories that were likely non-immune mediated: 22.0% . Macrolides , nitrofurantoin , and amoxicillin/clavulanate  were the antibiotics with the highest percentage of corresponding clinical histories that were likely non-immune mediated . Penicillin was the most prevalently listed antibiotic allergy , followed by sulfonamides  and fluoroquinolones .This study demonstrated the feasibility of using a standardized questionnaire to discern true antibiotic allergies from non-immune mediated adverse reactions. The improved accuracy of documented allergies allows for better optimization of antibiotic prescribing.All Authors: No reported disclosures.


The utilization of carbon-fiber-reinforced polymer (CFRP) composites as strengthening materials for structural components has become quite famous over the last couple of decades. The present experimental study was carried out to examine the effect of varied widths of externally bonded CFRP on the debonding strain of CFRP and the failure mode of plain concrete beams. Twelve plain concrete prims measuring 100 mm × 100 mm × 500 mm were cast and tested under identical loading conditions. The twelve specimens include two control prisms, i.e., without CFRP strips, and the remaining ten prisms were reinforced with CFRP strips with widths of 10 mm, 20 mm, 30 mm, 40 mm, and 50 mm, respectively, i.e., two prisms in each group. Four-point loading flexural testing was carried out, and the resulting data are presented in the form of peak load vs. midpoint displacement, load vs. concrete strain, and load vs. CFRP strain. The peak load was directly recorded from the testing machine, while the midpoint deflection was recorded through the linear variable differential transducer (LVDT) installed at the midpoint. To measure the strain, two separate strain gauges were installed at the bottom of each concrete prism, i.e., one on the concrete surface and the other on the surface of the CFRP strip. The results of this study indicate that the debonding strain is a function of CFRP strip width and that the failure patterns of beams are significantly affected by the CFRP reinforcement ratio.  Concrete is a widely used construction material in building infrastructure all around the world owing to its ability to be cast into shape, durability, cost-effectiveness, and high compressive strength ,2,3. PooFor more than 30 years, engineers have used externally bonded fiber-reinforced polymers to strengthen and increase the load-carrying capacity of reinforced concrete structures, but due to limited test data and a lack of comprehensive design standards, the engineering community at large is not very familiar with the design and application of fiber-reinforced polymers (FRP) to strengthen existing infrastructures. Hence, more test data are required to study failure modes . Guo et Currently, carbon-fiber-reinforced polymer (CFRP) plates and sheets are widely used in the construction industry for the strengthening and retrofitting of reinforced beams in flexure and shear ,13,14,15In the past, several studies have been carried out to investigate failure due to the loss of bond between the concrete and the FRP plate in an RC beam that is strengthened with the external bonding (EB) technique ,20,21,22The application of FRP in RC structures utilizing normal and self-compacting concrete on mechanical and durability characteristics  along with different design approaches that are available in various international design guidelines has been reviewed extensively in past, and it was concluded that more research is needed to investigate the maximum usable strain in externally bonded FRP material ,11,31.Thamrin conducted an experimental investigation to examine the effect of the reinforcement ratio on the flexural capacity of the beams and proposed a new model to compute the debonding moment. The results concluded that the ratio of tensile reinforcement, the ratio of the modulus of elasticity of concrete, the modulus of elasticity of the FRP plate, and the plate thickness have a significant influence on the debonding moment value . Garcez Salama tested nine reinforced concrete beams, out of which eight were strengthened in flexure with different configurations of bottom-bonded and side-bonded CFRP sheets, and the results were presented in the form of load–deflection response curves, failure modes, and ductility. Moreover, he found that the side-bonded strengthening scheme is a good alternative to the bottom-bonded scheme for strengthening RC beams in flexure, especially if the beam soffit is narrow or inaccessible for strengthening . ChoobboSaleem et al. determined the moment–curvature response of seven reinforced concrete beams strengthened with different amounts and layouts of CFRP reinforcement. The study showed that increasing the CFRP reinforcement above certain levels does not help appreciably, and that the structural performance can be optimized through an appropriate combination of CFRP flexural and shear reinforcement . Soares The problem facing externally bonded reinforcement and the near-surface mounted technique is premature debonding, which is due to the interfacial shear stresses between the concrete and FRP, i.e., bond behavior ,22,30. TAlthough the ultimate strength of over-reinforced beams was only slightly affected, the structural behavior of the beams was greatly enhanced by increasing the FRP reinforcement ratio . The tesIn past, some researchers have investigated the bond strength of an externally bonded CFRP with a concrete surface via an experimental program composed of a single-lap shear test , which pThe strain transferred from concrete to FRP will determine the overall strengthening achieved based on the stiffness of the FRP used for the strengthening purposes. All the focus of FRP strengthening design codes has remained to theoretically determine the amount of strain that can be achieved for a given reinforcement ratio of FRP.In this study, samples with different FRP ratios were tested under identical conditions, and the strain between concrete and FRP was closely monitored and presented for validation and evaluation for future studies. To investigate the pure flexural shear strain transfer from concrete to FRP, no steel reinforcement was provided inside the concrete prisms. To enable guidelines for future design recommendations and to facilitate strain evaluation model studies, the CFRP and concrete strains are presented and discussed in detail. For this, experimental testing was carried out to study the effect of varying the CFRP width on the flexural strains of the concrete beam specimens. All beam specimens were cast without internal longitudinal or shear reinforcement to investigate the pure concrete and CFRP strain transfer under a flexure load. During the flexural load test, the load, deflection, and strain values of CFRP and concrete were monitored closely.A total of twelve plain concrete prims without any internal longitudinal or shear reinforcement measuring 100 mm × 100 mm × 500 mm were prepared and tested with a clear span of 400 mm and a total length of 500 mm, as shown in Four-point load tests were conducted on the beam samples. This loading arrangement is per ASTM-C1399  with sliThe concentrated load was applied with a constant displacement rate of 1.5 mm/min. This displacement rate was decided based on the ASTM C1609  guidelinOut of twelve specimens, two samples were prepared without CFRP strips and are referred to as control specimens, and ten samples were prepared in a group consisting of CFRP strips with widths of 10 mm, 20 mm, 30 mm, 40 mm, and 50 mm. To study the effect of varied CFRP widths on strength, deflection, and strain, a range of CFRP widths was selected that covers 10% to 50% of the surface area of the concrete on the tension face of the prisms. An evaluation of the debonding strain was one of the objectives of the study. Therefore, CFRP widths up to 50 mm with 10 mm increments were considered. It was desirable to measure the CFRP and concrete strain at the extreme fibers, with widths higher than 50 mm, as the exposed area of concrete on either side of the CFRP strip remains too narrow to measure the strain values. Debonding strain is defined as the strain at which debonding starts and the peak load starts decreasing. Once this maximum value of strain (debonding strain) is achieved, it starts losing its strength, and delamination occurs. The length and thickness of the CFRP strips in the strengthened specimens were kept constant, equal to 1.5 mm and 400 mm, respectively. The designation of all test specimens is given in The designations C-1 and C-2 represent control specimen 1 and 2, whereas the typical designation 10-C-1 represents specimen 1 strengthened with a CFRP strip with a 10 mm width.fc′ = 32 MPa, which was determined as per ASTM C39 [Concrete beam samples were prepared from concrete with an average compression strength of ASTM C39 . The speASTM C39 . After cKeeping in view the local construction practices, 32 MPa concrete was adopted for this study. A nominal mix ratio of 1:2:3 was adopted for 32 MPa standard concrete in which one part of Portland cement was mixed with two parts of fine dry sand and three parts of coarse aggregate. A water/cement ratio of 0.42 (air-entrained) was considered and maintained for all batches of concrete mixes. The other properties of the concrete, such as the elastic and shear moduli of elasticity, were determined using ACI 318-19 . HoweverDuring experimentation, vertical displacement and the applied load were acquired using a data acquisition system. The experimental results of all specimens are summarized in terms of their peak load, midspan deflection, and their average values in It was observed that all beam samples that were strengthened with externally bonded CFRP depicted better results compared to control specimens (C-1 and C-2) in terms of load-carrying and deformation capacities. The beam sample strengthened with a 50 mm CFRP strip (50-C-2) showed the highest values of peak load (27.65 kN) as well as deflection (1.996 mm).The specimen C-1 depicted peak load values lower than the C-2 specimen, which was mainly attributed to the heterogenous behavior of concrete and the sensitivity of un-reinforced concrete samples to tensile stresses. However, for comparison purposes, the average value of both specimens (C-1 and C-2) was used. By increasing the width of the CFRP strips from 10 mm to 20 mm, the beam samples were able to undergo large deflections, an indication of better ductile behavior. However, in the comparison to the control samples, an average increase of 132.19% was noted in the load-carrying capacity as well as an increase of 73.64% in the deflection. According to In comparison to the control samples, on average increase of 152.54% in value was observed in the load-carrying capacity as well as a 92.31% increase in the deflection. In comparison to the control samples, the load-carrying capacity and deflection increased by averages of 203% and 109.9%, respectively. However, in comparison with the specimens that were retrofitted with 30 mm CFRP strips, the peak load and vertical displacement of the 40-C specimens increased by average of 12% and 9.14%, respectively.The load–deflection curves shown in In order to study the effect of CFRP reinforcement on the ultimate load-carrying capacity and deflection, the peak loads of all reinforced specimens  were normalized with reference to the control specimens (C) and are presented in The specimen 50-C-2 showed the highest value of the strain in concrete and CFRP at the ultimate load. The debonding of CFRP started at the peak load, and strains corresponding to the peak loads can be categorized as debonding strain in all these cases. Due to good bond behavior and the uniform transfer of shear stresses between CFRP and concrete, the strain values of the concrete and CFRP for each tested specimen were found to be very close to each other until the sample reached its peak load.As reported in The strain values of the CFRP and concrete for both specimens were very close to each other, which is a sign of uniform shear stress transfer between the CFRP and concrete. In comparison to the beam samples retrofitted with 10 mm CFRP strips, an average increase of 36% in the value of the concrete and CFRP strain was noted. Specimen 20-C-1 showed a peak concrete strain value of 125.28 and a peak CFRP strain value of 132.40, whereas sample 20-C-2 showed a maximum concrete strain value of 127.70 and a peak CFRP strain value of 134.16. By increasing the width of the CFRP strip from 10 mm to 20 mm, the strain values were increased.In comparison to the beam sample retrofitted with a 30 mm CFRP plate, samples 40-C-1 and 40-C-2 showed  an averaThe initial cracking pattern and the final overall failure modes of all specimens tested against the flexure loading were captured and are summarized in Due to the brittle behavior, sudden failure without initial warning occurred in the control specimens (C-1 and C-2), and the failure mode was regarded as pure flexural. It is quite evident in For samples that were strengthened with a CFRP strip with a width of 30 mm or less, no redistribution of the stresses was observed. This was due to the dominance of the concrete’s tensile cracking behavior. The provided CFRP reinforcement was not adequate to control the tensile cracking of the concrete at the peak load level, and debonding started, which could be witnessed with vertical flexural cracking in all these samples. However, in the case of the 40-C and 50-C samples, CFRP provided sufficient restraint against the pure flexural tensile cracking, and concrete shear stresses came into action, which resulted in the redistribution of stresses from pure flexure to flexure–shear behavior, and ultimately the samples failed in the flexural shear mode. It is difficult to relate this phenomenon with the moment redistribution of the reinforced concrete beams, as the failure pattern and collapse mechanism largely depend on the moment redistribution and the formation of plastic hinges. Similarly, a study conducted by Guella, F and Baji, H also discussed a similar behavior in relation to the moment redistribution in concrete structures ,54.In the case of the 40-C and 50-C samples, the failure modes shifted from pure flexure to shear flexural, as shown in CFRP improved the load-carrying capacity and deformation capacity of the retrofitted beam samples. However, this increase was not directly proportional to increase in the cross-sectional area of the CFRP. An effective substrate  plays a significant role in strength gain.An improvement in the peak strain values of concrete and CFRP was observed with an increase in the width of the CFRP. The maximum values of the strain (concrete and CFRP) were observed in beam samples retrofitted with 50 mm CFRP strips. The peak strain achieved in CFRP depends upon the effective substrate area . By increasing the width of the CFRP, the effective contribution of the substrate  increased, which assisted CFRP in achieving better strain. However, this peak strain was significantly lower than the ultimate strain of the CFRP and concrete. For samples 10-C, 20-C, and 30-C, failure was initiated due to the flexure rupture of concrete across the entire cross section, followed by debonding failure, whereas for 40-C and 50-C flexure–shear failure  was observed, which was followed by the debonding of the CFRP strip. Due to the wider strips, the effective substrate also became wider, which assisted the CFRP in gaining better strain values compared to 10-C, 20-C, and 30-C.The transfer of concrete and CFRP strains is highly dependent on good bonding behavior between these two materials. No damage to CFRP strips was observed, which shows that the CFRP used was significantly stronger. It is good for strength gain but could be costly if other system strength parameters such as the epoxy and concrete are weaker. In order to achieve an efficient strengthening design, the concrete surface properties shall be thoroughly assessed for effective strain transfers to FRP.Specimens strengthened with 40 mm and 50 mm CFRP strips had flexural shear failure. This implies that increasing the CFRP reinforcement beyond this point will not improve the beam’s overall load-carrying capacity until it is strengthened or reinforced for shear forces and stresses.The influence of different widths of CFRP on the debonding strain and failure patterns of concrete prims were investigated in this research paper. The CFRP strip widths were varied gradually to see their effect on peak loads, debonding strain, and deformation capacity. Based on the experimental test data, analysis, and discussion, the following conclusions have been drawn:


One of the disadvantages of reinforced concrete is the large weight of structures due to the steel reinforcement. A way to overcome this issue and develop new types of reinforcing elements is by using polymer composite reinforcement, which can successfully compensate for the shortcomings of steel reinforcement. Additionally, a promising direction is the creation of variotropic (transversely isotropic) building elements. The purpose of this work was to numerically analyze improved short bending concrete elements with a variotropic structure reinforced with polymer composite rods and to determine the prospects for the further extension of the results obtained for long-span structures. Numerical models of beams of a transversally isotropic structure with various types of reinforcement have been developed in a spatially and physically nonlinear formulation in ANSYS software considering cracking and crashing. It is shown that, in combination with a stronger layer of the compressed zone of the beam, carbon composite reinforcement has advantages and provides a greater bearing capacity than glass or basalt composite. It has been proven that the use of the integral characteristics of concrete and the deflections of the elements are greater than those when using the differential characteristics of concrete along the height of the section (up to 5%). The zones of the initiation and propagation of cracks for different polymer composite reinforcements are determined. An assessment of the bearing capacity of the beam is given. A significant (up to 146%) increase in the forces in the reinforcing bars and a decrease in tensile stresses (up to 210–230%) were established during the physically non-linear operation of the concrete material. The effect of a clear redistribution of stresses is in favor of elements with a variotropic cross section in height. Modern construction puts forward several specific requirements for buildings and structures, as well as for the building structures, products and parts from which these buildings and structures are built. In particular, the appearance of cities is changing, the share of high-rise and large-span buildings and structures is growing, engineering and geological conditions are becoming more complicated due to the lack of territories studied from the point of view of geology and there is a need to erect buildings and structures in difficult engineering and geological conditions, as well as in conditions of dense urban development. All this contributes to the fact that modern designers and builders need to build buildings considering many complicating factors. All these problems are relevant for the construction industry, and finding ways to solve them is the main task of modern design, construction and building science. Undoubtedly, one of the most principal elements of modern construction is reinforced concrete, as well as the products, parts and structures made of it. At the same time, precast concrete is still one of the most popular types of building products due to the fact that, in the factory, it is possible to clearly control the production process. Additionally, world science in the field of building materials science is developing new ways to improve compositions, recipes, technologies, design solutions and methods for calculating and designing building elements made of heavy concrete ,3,4,5,6.It should be noted that reinforced concrete, with all its advantages, also has several disadvantages, which are expressed in the high cost of raw materials, such as reinforcing steel, and the large weight of the created structures, products and buildings ,10,11,12Relatively new for reinforcement in the calculation of building structures is high-strength non-metallic reinforcement made of composite materials ,44,45,46If we talk about the nature of the destruction of reinforced concrete elements in shear, then the destruction in the shear of steel-reinforced concrete beams without transverse reinforcement often occurs suddenly and is brittle. In the case of fiberglass reinforcement, the nature of shear failure is different and is characterized by linear elastic behavior over the entire range of strength to failure. However, fiberglass reinforcing bars do not show plastic properties and break quickly. Therefore, the destruction of beams reinforced with fiberglass reinforcement during bending and shear occurs much faster than that of reinforced concrete beams. This condition indicates the importance of the process of designing bending elements reinforced with fiberglass reinforcement, considering both bending and shear. So, for example, in several works ,16,30,45Polymer composite reinforcement made of basalt fiber surpasses fiberglass reinforcement in its properties; however, it is inferior to carbon composite reinforcement. Additionally, basalt composite reinforcement is characterized by properties such as efficiency, resistance to high temperatures and a rather high limit of long-term strength ,47,48,57Mineral impregnated carbon fiber composites are a new type of reinforcement for construction. Compared to steel reinforcement, carbon fiber reinforcement has a much higher tensile strength and a significantly lower weight ,51,55,59We have already considered variotropic (heterogeneous in the cross section) centrifuged and vibrocentrifuged reinforced concrete products and structures and have also proved their high efficiency ,65,66,67Three types of polymer composite reinforcement were used in the study: glass composite reinforcement manufactured by Kursk Plant of Composite Materials LLC -GCR; basalt composite rebar manufactured by VZMK LLC -BCR; carbon composite fittings manufactured by Snabtekhmet LLC -CCR.The main physical and mechanical properties of polymer composite reinforcement (PCR) are presented in As the basic object of study, jumpers were selected with the following dimensions: height 90 mm; width 120 mm; length 1030 mm. Heavy concrete of experimental lintel beams was used .The calculation was carried out based on SP 52-101-2003 , SP 63.1The geometric dimensions of small lintel beams and the reinforcement scheme are shown in The production of products with a variotropic structure was achieved by placing an anode (anode zone) in the molded product in the zone of greatest strength and a cathode (cathode zone) in the zone of smallest strength, and a direct current was passed between them at a voltage gradient across the cross section of 0.5–5.0 V/cm V within 1–3 h from the moment of molding. After that, heat and moisture treatment were performed, or the products were kept until the concrete acquired tempering strength .Subsequently, the author proposed an improved method for the manufacture of concrete and reinforced concrete products, which differs from  in that,We note in particular that, in the experiments, the integral characteristics of the concrete were both studied—generalized over the cross section—and differentiated—differing in terms of the cross section due to the different effects in the cathode and anode zones during activation.To study the behavior of polymer composite  reinforcement reinforcing an inhomogeneous concrete beam, and to analyze their joint work, an FEM model was built in the ANSYS environment. The X-axis is directed along the longitudinal axis of the beam, the Y-axis is directed upward from the bottom face to the top and the Z-axis is directed perpendicular to the XY plane. Since the structure is symmetrical with respect to the OYZ plane, it makes sense to build half of the model.The inhomogeneity over the cross section of the beam is represented by three layers (transversely isotropic medium), the properties of which are presented in Concrete  is represented by 8-node SOLID65 elastoplastic elements designed to model reinforced concrete with the possibility of cracking; reinforcing bars .Variotropic concrete reinforced with basalt composite rebar (BCR).Variotropic concrete reinforced with carbon composite rebar (CCR).For the analysis, three models were built:The mechanical characteristics of concrete and reinforcement layers are presented in All nodes with coordinate x = 0 are fixed in the direction of the Ox axis.All nodes with coordinates x = −l/2; y = 0 are fixed in the direction of the Oy axis, where l is the length of the beam.The node with coordinates x = 0; y = 0; z = −b/2 is fixed in the direction of the Oz axis, where b is the width of the beam.All nodes with coordinates x = 0; y = h are connected in the direction of the Oy axis, where h is the height of the beam.Force F = 7 kN is applied vertically down to the node with coordinates x = 0; y = h; z = b/2.Boundary conditions of the problem a,b:All nThe scheme of the finite element partitioning of the polymer composite reinforcement is shown in (1)polymer composite-reinforced bending elements of the rectangular section;(2)transversally isotropic bending-reinforced concrete elements;(3)transversally isotropic polymer composite-reinforced bending elements.Based on the experimental data of works ,77,78, wThe study of normal stress fields in concrete and reinforcement during loading shows that the moment of concrete cracking occurs at a load of about 3000 N. Until this moment, both reinforcement and concrete are loaded classically, with a uniform increase in stresses to their maximum values in the middle of the beam (3.42 MPa for concrete and 4.42 MPa for reinforcement). te rebar b–e showsIt can be seen that, in the GCR beam a, cracksIt can be seen a,c that The successive development of cracks in a transversally isotropic beam is shown in It can be seen that, at a load of 3000 N a, concreA further increase in the load clearly reflects the abovementioned nature of the redistribution of stresses . So, at The dynamics of the development of cracks in concrete can be seen in The stress fields and the nature of the destruction of concrete for beams reinforced with basalt composite and carbon composite reinforcement have a similar nature; the differences are only in terms of numerical values. The analysis of the values is presented below.First, let us analyze the changes in compressive stresses in concrete .By analyzing the graph of compressive stresses in concrete, it can be seen that the increase in stresses with increasing loads occurred according to a quadratic dependence from 2.8 to 4 kN. This is explained by the fact that the stresses grew both due to an increase in the load and due to a decrease in the beam section due to cracking. After active cracking by 4 kN and more—up to 7 kN—the increase in stresses occurs mainly due to an increase in the load, that is, due to one factor. Therefore, the growth graph acquires an almost linear dependence. It can be seen that the compressive stress in carbon fiber reinforcement is the smallest, that is, it is approximately 25–30% less than that of fiberglass and 20–25% less than that of basalt reinforcement.Next, we present a graphical interpretation and analysis of the results on compressive stresses in reinforcement .When analyzing the graph of compressive stresses in the reinforcement, it can be seen that the ratio of stresses in the reinforcement correlates with the ratio of the deformation moduli of these materials from which the rods are made. As can be seen, more rigid carbon composite reinforcement takes on approximately 2.2–2.4 times greater compressive stresses than basalt and fiberglass. Basalt with fiberglass has very close values, which indicates approximately equal characteristics. It can be seen from the graph that, in the area from 3.5 to 4 kN, a surge of stresses is observed, after which their gradual linear decrease to the initial values occurs. Thus, we pay attention to the surge of stresses during the period of active cracking and the further redistribution of stresses to the compressed zone of concrete. Thus, by removing stresses from the reinforcing bars, the stresses are redistributed to the concrete.Consider and analyze the changes and the identified dependencies for tensile stresses in the reinforcement .Before active cracking, the tensile stresses in the reinforcement, as well as the compressive ones, were proportional to the ratio of the deformation moduli, that is, the carbon composite reinforcement-assumed stresses that were two times higher than the stresses of fiberglass and basalt reinforcement. After 3.5 kN, after the start of active cracking, we find that there is an uncontrolled increase in stresses by two orders of magnitude, that is, hundreds of times. At the same time, we cannot clearly say which armature has more stress and which has less, that is, the graphs show heap, dense results. Accordingly, it can be seen here that the differences in work are relevant until the moment of active cracking.Finally, let us analyze the results obtained for beam deflections .The analysis shows that, again, in the zone of elastic work before cracking, we see linear dependencies, and after 3.6 kN, the deflections begin to grow more actively due to cracking. Since the cross section decreases due to cracks, the stress in the reinforcement begins to grow enough at this moment actively, and at the same time, we see a significant increase in deformations. According to the deformations, we see that deflections in the variant with carbon fiber reinforcement are also 2–2.5 times less than those with fiberglass and basalt composite reinforcement. This suggests that the rigidity of carbon fiber reinforcement is more than two times greater, respectively, with equal tensile stresses, which we described in the previous graph. It gives proportionally less deformation, that is, it is stiffer and deforms less.The graph of deformations in concrete is shown in Summarizing all four previous graphs, we can summarize the following results.For composite reinforcement, it is very important to take into account the work at the stage before active cracking. While it works quite predictably, stress deformations are easily determined, and there is no fluctuation. However, after active cracking, we see that there is a sharp increase in deformations and a sharp increase in stresses, both in concrete and in reinforcement.Thus, we must clearly monitor the conditions for not exceeding the limiting moment for the onset of cracking in order to prevent uncontrolled processes in any case. However, at the same time, the manifestation of such a property as the formation of cracks in composite reinforcement is the weakest point, that is, it is the most critical parameter for them, since the issue of adhesion to the surrounding concrete due to winding is relevant, that is, the winding there is not as controlled as that in steel reinforcement, and the issue of small deformation moduli is also relevant. At the same time, we note carbon fiber reinforcement to be the one that works most adequately under conditions of active cracking; however, stresses there also grow quite strongly, and there is still a risk of uncontrolled deformations despite the fact that deformations occur two times less frequently than those of fiberglass.It is confirmed that fiberglass and basalt rebar are very controversial materials. When they are used in design and construction, it is necessary to clearly monitor the process of cracking, the process of deformation and the process of stress growth.Considering the significant novelty of this study in terms of a non-trivial approach to the manufacture of reinforced concrete products and structures, we will compare the results obtained by us with the results of other authors in two aspects. The first aspect is the integral comparison of the indicators of the received beams with the help of recipe-technological and design solutions proposed by us. Thus, a polymer composite-reinforced beam has advantages over a bent element of a similar section made using standard steel rods due to higher structural characteristics and the lower weight of the resulting structure, as well as the reduced cost. For example, due to the activation of concrete and giving it a variotropic structure, we reduced the deflections of short lintel beams with polymer composite reinforcement to 3%. This is in contrast to , the defIn this regard, the results obtained by us in the design characteristics, which do not affect the change in concrete along the height of the variotropic section, compare favorably in the direction of acquiring advantages in relation to works such as ,3,4,5,6.Thus, we continued research ,78 and d(1)Numerical models of lintel beams of non-variotropic and variotropic structures with various types of reinforcement, made in a spatial formulation by physically linear and non-linear elements, have been developed. The stress-strain state of the concrete of lintel beams and polymer composite reinforcing bars of all considered types was studied.(2)It has been established that, in a physically nonlinear setting, when using the integral characteristics of concrete, the deformability (deflections) of the elements is greater than that when using the differential characteristics of concrete along the height of the section (up to 5%). This trend is similar for all bending elements, regardless of the type of polymer composite reinforcement used.(3)In the upper, most compressed zone, an increase in the compressive strength of concrete is required, and in the tensile zone, concrete practically does not work. Concrete transfers all forces to the reinforcement in the central zone in the middle of the beam at the bottom edge. In this case, the effect of a clear redistribution of stresses is in favor of elements with a variotropic cross section in height. The compressed fibers in the uppermost zone are most susceptible to anodizing, i.e., the highest strength. The height of the compressed zone of concrete is in this zone, where the work of the structure is most effective.(4)It has been established that, in variotropic bending elements, carbon fiber reinforcement works most adequately under conditions of active cracking; however, stresses there also grow quite strongly, and there is still a risk of uncontrolled deformations, despite the fact that deformations occur two times less frequently than those of fiberglass. It is confirmed that fiberglass and basalt rebar materials are very ambiguous. When they are used in design and construction, it is necessary to clearly monitor the process of cracking, the process of deformation and the process of stress growth.We theoretically substantiated and confirmed, by numerical simulation, the efficiency of the operation of variotropic bending elements reinforced with polymer composite reinforcement in physically linear and nonlinear formulations.The continuation of the work is planned in the direction of conducting experimental studies and comparing the results of the numerical simulation with the results obtained in laboratory or field conditions.


The “learning health system” (LHS) concept has been defined in broad terms, which makes it challenging for health system leaders to determine exactly what is required to transform their organization into an LHS. This study provides a conceptual map of the LHS landscape by identifying the activities, principles, tools, and conditions that LHS researchers have associated with the concept. Through a multi‐step screening process, two researchers identified 79 publications from PubMed (published before January 2020) that contained information relevant to the question, “What work is required of a healthcare organization that is operating as an LHS?” Those publications were coded as to whether or not they referenced each of 94 LHS elements in the taxonomy developed by the study team. This taxonomy, named the Learning Health Systems Consolidated Framework (LHS‐CF), organizes the elements into five “bodies of work”  and four “enabling conditions” . We report the frequency that each of the 94 elements was referenced across the 79 publications. The four most referenced elements were: “organization builds knowledge or evidence,” “quality improvement practices are standard practice,” “patients and family members are actively engaged,” and “organizational culture emphasizes and supports learning.” By dissecting the LHS construct into its component elements, the LHS‐CF taxonomy can serve as a useful tool for LHS researchers and practitioners in defining the aspects of LHS they are addressing. By assessing how often each element is referenced in the literature, the study provides guidance to health system leaders as to how their organization needs to evolve in order to become an LHS ‐ while also recognizing that each organization should emphasize elements that are most aligned with their mission and goals. It is highlighted in the charter of NAM's Leadership Consortium: Collaboration for a Value and Science‐Driven Health System.The following definitions of LHS were offered by the Institute of Medicine (IOM) in 2007 and 2013, respectively:AHRQ released a similar, although less detailed definition of LHS in 2019:“In a learning health system, internal data and experience are systematically integrated with external evidence, and that knowledge is put into practice. As a result, patients get higher quality, safer, more efficient care, and health care delivery organizations become better places to work.” (1).By design, these definitions are broad and aspirational, leaving out the details that would guide healthcare organizations on the specific work they should be carrying out. According to the 2007 IOM report, LHS is purposefully presented as a broad definition, which can be adapted to different contexts.1.1The current study uses a targeted review and analysis of relevant scientific literature to identify the various elements that have been associated with operating as an LHS and to provide a sense of which elements are emphasized by LHS researchers. The key product of the study is a comprehensive taxonomy accompanied by frequency counts for each element. The study focused specifically on publications where authors described what healthcare organizations are doing ‐ or should be doing ‐ in accord with the LHS concept. Publications meeting this criterion were reviewed by qualitative researchers who identified text passages that communicated how the authors were conceptualizing LHS. That text was then coded according to a taxonomy to determine which elements were present in each publication.1.2It is important to reiterate that this study is focused on one specific form of LHS, namely individual healthcare organizations that are conducting systematic learning in support of improved patient care. As Guise, Savitz, and Friedman point out, there are other entities  that are aiming to act as an LHS.2The study involved a review and qualitative analysis of scientific publications that offer a perspective on what it means for a healthcare organization to operate as an LHS. Three distinct tasks were carried out: 1) identification of relevant publications; 2) development of a taxonomy of the principles, practices, tools, and conditions that researchers have associated with acting as a learning health system; and 3) coding of publications according to that taxonomy.2.1The search for publications was performed within the PubMed database on January 28, 2020. The following four queries were used in the search field: “learning health system,” “learning health systems,” “learning healthcare system,” and “learning healthcare systems.” All publications returned from these four searches (regardless of publication date) were included in the screening process.“learning health system” (n = 298),“learning health systems” (n = 219),“learning healthcare system” (n = 114),“learning healthcare systems” (n = 43).The four PubMed searches returned the following numbers of publications:Combining these four sets of publications and eliminating duplicates generated a list of 580 potentially eligible publications.Inclusion criteria. Publications were included in the analysis if they met any of the following criteria: 1) described the practices and organizational characteristics that healthcare organizations should adopt or have in place in order to qualify as an LHS; 2) recommended what healthcare organizations should do to transition to and/or maintain an LHS; 3) recommended a specific learning system or learning cycle for healthcare organizations to adopt; or 4) provided an example of a healthcare organization that is operating as an LHS. To be included in the study, the publication also needed to offer specific guidance that went beyond simply restating the definition of LHS offered by IOM, NAM, or AHRQ.Screening process. The screening process yielded 79 publications that met the eligibility requirements for the study. The flow diagram for the process is shown in Figure For those 61 publications, the researchers independently reviewed the full text, made a determination and compared their classifications. After reviewing the full text, 14 publications that appeared to meet the eligibility criteria advanced to the coding stage of the study. The 109 “appears to meet eligibility criteria” publications were each slated for full‐text coding. During that coding process, the coders determined that 30 of the publications did not meet the eligibility criteria. Thus, the final corpus comprised of 79 publications.The excluded publications fell into one or more of the following categories: 1) did not devote any attention to LHS in the text, even though LHS was listed as a keyword; 2) made only a passing reference to LHS as a concept somehow related to the focus of the publication; 3) conceptualized LHS narrowly as a particular form of clinical data system rather than a more comprehensive approach to be adopted by healthcare organizations; or 4) conceptualized LHS as a network of organizations – either a national network or a network focused on a particular disease or patient population  – without describing the work that occurs within individual members of the network.2.2Selected publications were coded according to a taxonomy that delineates the various principles, practices, tools, and conditions that these publications associate with healthcare organizations operating as an LHS. The taxonomy consists of 94 elements, which relate to topics such as organizational learning, continuous quality improvement, conducting research, clinical data systems, translation of knowledge into practice, engaging stakeholders, skills and training, and organizational policies and culture.The 94 elements include 38 primary elements and 56 secondary elements. A secondary element is one that provides additional specificity for a primary element. For example, the primary element, “Findings from research are shared or disseminated” has two secondary elements: “Shared internally within the organization” and “Shared externally.”Initial development. The LHS taxonomy was developed through an iterative process, starting with a pilot study, which qualitatively analyzed a limited set of LHS‐related publications. In this pilot study, two librarians at the Coy Carpenter Library at Wake Forest School of Medicine conducted a literature search with a broad lens that included LHS and “organizational learning” within healthcare organizations. The librarians identified 29 publications offering a range of perspectives. The study team reviewed those publications and selected those that provided information on LHS principles and practices. Each of the 12 selected articles was analyzed using NVivo qualitative software.Testing and refinement. This draft taxonomy was applied and expanded during the “testing” phase of the current study. Following the PubMed search and screening process described above, the study team purposefully selected 14 publications offering a diverse range of perspectives on the LHS construct. Two researchers independently coded these 14 articles, while also noting LHS‐relevant text that did not fit any of the existing codes. Coding results were compared and discussed by the two researchers and the principal investigator. This process occurred in three waves. The first wave included review and discussion of codes for the first five publications. The second wave brought in five additional publications and the third wave, the remaining four publications. These meetings included decisions to add missing codes to the taxonomy and to clarify ambiguous codes.At the end of this testing phase with the 14 publications, the taxonomy had expanded from 19 elements to 85 elements (32 primary and 53 secondary). This expansion resulted from two factors. First, the 14 publications coded in the testing phase included a number of LHS‐related features not mentioned in the 12 publications analyzed during the pilot study. Second, some of the elements generated during the pilot study were deemed to be too broad and/or to connote multiple constructs. Whereas the pilot study provided a first‐cut “unpacking” of the constructs that have been associated with LHS, the testing phase was designed to create a taxonomy of more specific elements that could be used to code text in LHS publications.One tactic in creating a more fine‐grained taxonomy was to include secondary elements as a means of representing key distinctions and specifications that arose when authors described concepts such as learning processes, dissemination, implementation, and engaging stakeholders. In developing secondary elements for a particular primary element, we sometimes specified a secondary element that we expected to be relevant to publications that would be coded beyond the testing phase. For example, “implements with fidelity” was included as one of five secondary elements for “the organization is systematic in its implementation processes” because we assumed this would be mentioned in at least one publication ‐ although this turned out not to be the case.The taxonomy evolved modestly (from 85 to 94 elements) as additional publications were reviewed and coded during the analysis phase. When coders encountered LHS‐relevant text that did not fit the existing taxonomy, they flagged the text and brought it up for discussion and resolution in the weekly conversations between the two coders and the principal investigator. Those meetings also led to further clarification of the coding rules.The 14 publications used to develop the taxonomy were included in the main analysis. Because the taxonomy expanded during the testing phase, these 14 publications were re‐coded according to the revised taxonomy.2.3The intent of the coding process was to determine, which elements of the LHS construct were mentioned in each publication. Two researchers reviewed and coded each of the publications that met the inclusion criteria. The coding process involved identifying passages pertaining to the conceptualization of LHS and then assigning those passages to the appropriate item within the LHS taxonomy. A codebook (available upon request) was created with rules for when to apply a particular LHS element.The coding process was performed using Dedoose software for qualitative analysis.As an indication of how much reconciliation was required, we assessed inter‐rater agreement in coding prior to the reconciliation meetings . This involved the calculation of Cohen's Kappa for a sample of 10 publications at roughly the mid‐point of coding process. The practical question behind this calculation was whether there was enough agreement between the coders to move toward single‐person coding. The observed Kappa was 0.705, indicating “moderate” agreement.In summary, each step of the process, including taxonomy development, screening, and coding, was completed by two members of the research team. One individual was consistent for all of these steps, while the second individual changed for each step in the process.33.1Learning Health Systems with 14 publications (or 18%). The Journal of Comparative Effectiveness published four of the articles in the sample, while NAP published four of the books in the sample. No other journal had more than three articles represented in the sample.The 79 publications in our sample were published by 50 different journals, plus National Academies Press (NAP). The journal with the highest representation was The 79 articles/books were published between 2009 and January 2020 (which is when the search was performed). Publication dates are plotted in Figure The publications referenced a variety of healthcare organizations when presenting LHS research findings and making recommendations for LHS work. Fourteen of the publications (18% of the sample) referenced an academic health system, while seven (9%) referenced a non‐academic health system. The highest representation was Nationwide Children's Hospital with three publications. In addition to these 21 publications that referenced particular healthcare organizations, the sample included 8 (10%) publications that referenced both academic and non‐academic health systems, and 6 (8%) that referred to a national network of healthcare organizations. Over half of the publications  did not explicitly identify the type of organization that served as the context for their study or recommendations.3.2The coding process generated an “LHS profile” for each publication, where each of the 94 elements in the taxonomy was determined to be either present or absent. The 79 publications each had their own unique profile. The median number of elements mentioned was 12, although this figure varied widely across the 79 publications. At the low end was a publication that referenced only two elements. At the high end was a publication that referenced 38 elements (22 primary and 16 secondary).3.3Tables Organizational learning, innovation, and continuous quality improvement that leads to improved patient care;Identifying, critically assessing, and translating knowledge and evidence into improved practices;Building new knowledge and evidence around how to improve healthcare and health outcomes;Analyzing clinical data to support learning, knowledge generation, and improved patient care; andEngagement of clinicians, patients, and other stakeholders in processes of learning, knowledge generation, and translation.The four enabling conditions are:The organization has a critical mass of employees with the skills and knowledge necessary for LHS work;Data systems, informatics technology, and resources are in place within the organization to support analyses of clinical data that address the organization's learning questions;The organization invests resources that are sufficient to carry out the different bodies of LHS work; andThere is a supportive organizational culture with norms, policies, and visible leadership that support LHS work.Table Within Tables Table 3.4Figure Among the four enabling conditions, two were referenced by approximately two‐thirds of the publications: “data systems and informatics resources in place” and “supportive organizational culture.” The remaining two enabling conditions (“workforce skilled in LHS work” and “organization invests resources in LHS work”) were each referenced in only about one‐third of the publications.This domain‐level grouping of elements allowed us to also assess the degree to which the publications were comprehensive in covering the five bodies of work and four enabling conditions in their descriptions of LHS. The majority of publications referenced either all five bodies of work (23 publications or 29%) or four of them . In contrast, 17 publications (22%) focused on only 1 or 2 bodies of work. The publications were less comprehensive in referencing enabling conditions. Only 11 (14%) referenced all 4 enabling conditions and another 10 (13%) referenced 3 of them. The majority (52 or 66%) referenced only 1 or 2 enabling conditions. Six publications did not mention any enabling conditions.44.1This study used a targeted review and analysis of the LHS literature to identify the work that healthcare organizations are doing or should be doing on the way toward becoming an LHS. Our first finding involved the size and diversity of principles, practices, and conditions that researchers point to when describing LHS. In order to capture the full range of LHS‐related issues raised in this sample of publications, we needed to create an extensive taxonomy with 38 “primary” elements, 16 of which are further specified with “secondary” elements. Tables A second overarching result was that the elements associated with LHS fall into two distinct categories: LHS work  and enabling conditions that need to be present within a healthcare organization in order for LHS work to be carried out. We further categorized the elements into five “bodies of work”  and four “enabling conditions” .4.2We believe that these five bodies of work and four enabling conditions serve as a useful framework for organizing LHS research, as well as the planning, budgeting, management, leadership, and evaluation that is required to transform a healthcare organization into an LHS. Figure The top portion of the LHS‐CF figure shows that the five bodies of work are interconnected and mutually reinforcing. The bottom portion shows that LHS work is facilitated by (and depends upon) the four enabling conditions.It is important to point out that LHS‐CF is consistent with the current NAM definition of LHS, while also adding a conceptual mapping of the different areas of work that are covered within the definition. Perhaps most importantly, LHS‐CF makes a clear distinction between the work that occurs within an LHS and the conditions that need to be in place to support that work. Moreover, LHS‐CF emphasizes the fundamental importance of a supportive organizational culture by making it the foundation of the figure. This was the most widely referenced enabling condition within our sample of publications, which is consistent with the prominence of organizational culture within theories and frameworks for implementing complex interventions.At the core of LHS‐CF is the fundamental purpose of LHS work: “to improve the quality, value, safety and equity of patient care, leading to improved health.” This intent is drawn directly from the characterizations of LHS that have been championed by NAM and AHRQ over the past 13 years. The publications reviewed in our study affirmed that the LHS concept is concerned primarily with improving the care delivered by health systems to their own patients, with the collateral benefit of contributing new knowledge and innovation that helps other organizations also improve their care. We have added an emphasis on equity because this is increasingly being recognized as a critical goal for health systems with regard to patient care and population health. Six publications in our sample explicitly mentioned equity as a goal that should guide the learning that occurs within an LHS. Equity has become even more prominent among LHS articles published since January 2020. For example, Allen et al.4.3The second aim of the study was to determine, which forms of LHS work and enabling conditions have been emphasized in the literature, with the expectation that these findings can provide guidance to health system leaders in determining what needs to be built or enhanced within their organizations in order to qualify as an LHS. Toward that end, Tables Tables In addition, we believe that some of the less frequently mentioned elements in the framework (not included in Tables 3 and 4) are quite important for health system leaders to incorporate into their planning and decision making. The most important of these in our view is “the organization invests resources in research that addresses its priority questions” (referenced in nine publications). Along similar lines, we would also highlight “The organization employs embedded researchers (researchers with LHS competencies who carry out studies that address the interests of clinicians and administrators),” which was also referenced in nine publications. We believe that any health system leader considering the idea of transforming their organization toward an LHS needs to be fully cognizant that this involves extensive and sophisticated new work requiring significant monetary investments, hiring of new staff with specialized skills, and re‐allocation of effort toward continuous learning and knowledge generation.One other important qualification in using Tables 4.4The LHS‐CF model was derived from a comprehensive review and systematic analysis of literature that describes the work carried out by healthcare organizations that are operating within the LHS paradigm. The sample included peer‐reviewed journal articles, workshop proceedings, and book‐length monographs. However, the search was limited to publications included in the PubMed database. Other documents describing the LHS concept certainly exist. It is possible that they point to features of the LHS concept not included in our taxonomy. Similarly, the larger literature base might have a different frequency distribution of LHS elements than was found in the 79 publications reviewed in this study. Our hypothesis, which warrants testing, is that the elements found to be most frequent in our sample will also be most prominent within the broader literature.A second limitation to our approach is that we focused on the proportion of publications mentioning an element as the basis for assessing the centrality of the element to the LHS construct. Some elements  might be of intense interest to a relatively large number of academics who publish LHS‐related articles, but may not be the most essential elements from the standpoint of those who have the greatest expertise or authority with regard to defining and implementing the LHS concept. In addition, it may be that the scientific literature on LHS under‐recognizes and/or under‐emphasizes some of the elements that are most essential to creating and sustaining a high‐functioning, high‐payoff LHS. One example from our standpoint is “the organization invests its own funds to conduct LHS research.”A third limitation is the evolution of the LHS concept over time. This study was based on articles listed in PubMed as of January 2020. The literature on LHS is expanding rapidly. As it does, there may be significant shifts in the relative frequency of elements within the taxonomy.5Our intent with this study was to provide the leaders of health systems with a clearer view of the specific types of work that need to be launched and supported in order to operate according to the principles of an LHS. With this clarity comes a greater appreciation of how the organization needs to evolve and what sorts of investments will be required.We believe that LHS‐CF can provide useful guidance for the implementation of LHS within health systems ‐ by pointing to the range of activities, approaches, tools, conditions, and principles that are associated with the concept. On the other hand, becoming an LHS involves specific decisions about concrete work. Each health system needs to operationalize LHS in ways that fit with its own mission, values, and needs.We expect that the LHS‐CF model will cause some health system leaders to regard the LHS concept as a more ambitious endeavor than was implied by the shorter definitions of LHS proffered by NAM and AHRQ. Many healthcare organizations will need to make major enhancements to their clinical data system in order for employees to be able to readily access the data and conduct analyses that answer their learning questions . The LHS‐CF model also makes it clear that analyzing clinical data and building knowledge requires professional staff with specialized skills. Hiring these individuals will require significant financial investments and may divert resources away from clinical operations. In theory, building out the capacity to conduct LHS work will return dividends with regard to more efficient care delivery, but this calculus presumes a long time horizon for investment decisions.The situation is different for academic health systems. They begin the LHS journey with considerable capacity in research and informatics, and typically have clinical data systems that are well suited to learning‐oriented analyses. To the extent that clinicians in the health system are actively engaged in the conduct of research, there might be direct routes for translating knowledge into practice, and more particularly for implementing evidence‐based interventions studied within the institution. On the other hand, many academic health systems have chasms between the research and clinical enterprises, which limits the amount of translation that occurs.Regardless of what type of healthcare organization, becoming an LHS will be a challenging journey. All healthcare organizations will need to develop new competencies, invest in new infrastructure, and engage in new practices in order to meet the expectations associated with the LHS concept.The authors report no conflicts of interest.