Prescribing of systemic antibiotics in general and of cephalosporins in particular in German paediatric outpatients has previously been reported to be higher than in other European countries.Our objective was to assess recent trends in antibiotic prescribing in German children.This study was conducted as consecutive annual cross-sectional analyses and included all children aged 0–14 years  covered by statutory health insurance in Germany. Annual antibiotic prescription rates from 2010 to 2018 were calculated for the age groups 0–1, 2–5, 6–9 and 10–14 years. Poisson regression was used to estimate trends of prescription rates by age group and antibiotic subgroup.Overall, the age-standardised antibiotic prescription rate decreased significantly by 43% from 746 prescriptions per 1,000 persons in 2010 to 428 per 1,000 in 2018 (p < 0.001). Reductions were most pronounced in the age groups 0–1 year (−50%) and 2–5 years (−44%). The age group 2–5 years exhibited the highest prescription rate with 683 per 1,000 in 2018 . Cephalosporins (second and third generation) accounted for 32% of prescribed antibiotics.Marked reductions in antibiotic prescribing during the last decade indicate a change towards more judicious paediatric prescribing habits. Compared with other European countries, however, prescribing of second- and third-generation cephalosporins remains high in Germany, suggesting frequent first-line use of these substances for common respiratory infections. Considerable regional variations underline the need for regionally targeted interventions. Antibiotic resistance is considered an emerging threat to global public health. Among other factors, exposure to antibiotics is a leading cause for the proliferation of resistant bacterial strains on individual  and popuData from 2008 illustrated wide variability of outpatient paediatric antibiotic prescribing patterns in European countries . With a For the years 2010 to 2014, a study based on German nationwide data illustrated a strong decline in outpatient antibiotic use among children and adolescents in the age group 0–14 years by ca 30% [Our study was designed as consecutive annual cross-sectional analyses based on nationwide outpatient prescription data of all children and adolescents aged 0–14 years covered by statutory health insurance (SHI) in the years 2010 to 2018. These data cover ca 83% of the German population in this age group and comprise all prescribed and dispensed ambulatory medications , in accordance with §300 paragraph 2 SGB  V. They include the patient’s age, the date of prescription, the pharmacy dispensation date, the amount of the prescribed substance, the anatomical therapeutic chemical (ATC) code, the defined daily doses (DDD), packaging size, strength and formulation as well as the generic and trade names. The study authors had unrestricted access to the database used. The study population was divided into the age groups 0–1, 2–5, 6–9 and 10–14 years, following recommendations for age categorisation in paediatric clinical studies . The totOutpatient prescriptions of systemic antibiotics (ATC code: J01) were divided into the following subgroups: broad-spectrum penicillins (J01CA), narrow-spectrum penicillins , penicillins with beta-lactamase inhibitors (J01CR), first-generation cephalosporins (J01DB), second-generation cephalosporins (J01DC), third-generation cephalosporins (J01DD), sulphonamides/trimethoprim  and macrolides (J01FA). Less frequent antibiotics were pooled in the subgroup ‘others’. Use of systemic antibiotics was measured as the annual prescription rate, i.e. the number of prescriptions per 1,000 persons per year, in total and by age group, federal state as well as antibiotic subgroup. As dosage of antibiotics depends on a patient’s age and body weight, prescription rates are more appropriate to describe antibiotic use among children and adolescents in different age groups than DDD per population .A study of outpatient antibiotic prescriptions from the Netherlands showed that the vast majority of antibiotics are prescribed as single course . We assuWe estimated the annual percentage change in prescription rates using Poisson regression. The analysis was based on monthly prescription rates and models were run separately for each age group and antibiotic subgroup. Season was included as a dummy-coded variable with four categories, one for each quarter of a year . We assumed that there was a log-linear relationship between the year and the prescription rate. Rate ratio (RR) estimates for calendar year and season as well as corresponding likelihood ratio test p values were calculated. As calendar year was included as continuous variable, RR-1 corresponded to the mean estimated relative change in prescription rate from one year to the next. All models incorporated a dispersion parameter to avoid overdispersion. Statistical analyses were conducted using SAS 9.4. In Germany, the use of data from insurance claims for scientific research is regulated by the Code of Social Law (SGB X). Ethical approval and informed consent were not required as our study used routinely collected anonymised data.In 2018, the study population comprised 1,328,589 (14%) children in the age group 0–1 year, 2,520,176 (27%) in the age group 2–5 years, 2,446,918 (26%) in the age group 6–9 years and 3,093,500 (33%) children and adolescents in the age group 10–14 years. Between 2010 and 2018, the size of the population aged 0–14 years increased by 3% from 9,132,142 to 9,389,183.Between 2010 and 2018, the age-standardised antibiotic prescription rate in children and adolescents (0–14 years) decreased by 43% from 746 (2010) to 428 (2018) prescriptions per 1,000 persons per year , correspThe highest percentage decrease in the prescription rate by almost half  was observed in the age group 0–1 year . On the absolute scale, 2–5 year-olds showed the highest reduction in the prescription rate with 530 fewer prescriptions per 1,000 persons in 2018  compared with 2010 , corresponding to a percentage decrease of −44%  . NeverthWith the exception of penicillins with beta-lactamase inhibitor, prescription rates of all antibiotic subgroups decreased markedly. Relative reductions varied between −64% (macrolides (RR: 0.88) and third-generation cephalosporins (RR: 0.88)) and −27% (broad-spectrum penicillins (RR: 0.96) and narrow-spectrum penicillins (RR: 0.97) . The vasIn 2018, broad-spectrum penicillins and second-generation cephalosporins were the most dispensed antibiotic subgroups in all age groups, amounting to 55% of antibiotics prescribed for German children  . For theThe regional distribution of prescription rates revealed a cluster of high paediatric use in western Germany comprising the federal states North Rhine-Westphalia, Rhineland-Palatinate and Saarland . Over thOur study on recent trends in antibiotic prescribing in the outpatient paediatric setting in Germany showed marked reductions in prescription rates over the last decade. The rates declined strongly in all regions, for the vast majority of antibiotic subgroups and for all paediatric age groups, but the relative reductions were most pronounced in very young children (0–1 year-old).In Europe, country-specific outpatient antibiotic use in the total population is continuously monitored and published in annual reports by the European Surveillance of Antimicrobial Consumption Network (ESAC-Net), repeatedly showing considerable variations in prescribing across countries . These dIn Germany, a considerable downward trend in paediatric antibiotic use may have been triggered by rising public awareness regarding the threat of antibiotic resistance, accompanied by increasing media coverage and an increasingly critical view of the use of antibiotics . In EuroOther factors include an increasing focus on judicious prescribing habits in continuous medical training of German physicians and the release of two national guidelines for medical practice, one by the National Association of Statutory Health Insurance Physicians in 2012 for the management of respiratory infections in general  and one Finally, the introduction of pneumococcal vaccination in Germany in 2006 is likely to have contributed to the decrease in paediatric prescription rates as vaccination uptake increased strongly during the years of our study . PneumocThe observed prescription rate in German children (0–14 years) of 428 prescriptions per 1,000 persons in 2018 was considerably lower than in Italian children in 2016  and lowSimilar to Germany, considerable intra-country variation in paediatric prescribing has also been reported for Denmark, Slovenia and Italy -38. ReasClostridium difficile infections in children [Wide variability in Europe concerning the choice of antibiotic subgroups is well acknowledged for the paediatric setting as well as the total population ,15. In Gchildren  and are children . In contrast, use of cephalosporins in children and the total population is negligible in Scandinavian countries, the Netherlands and the United Kingdom ,17,18,37Our study provides a comprehensive analysis of recent trends in paediatric antibiotic prescription rates in Germany based on a full sample of nationwide outpatient prescription data of all individuals covered by SHI, i.e. 83% of German inhabitants in the age group 0–14 years. This contributes to ongoing surveillance of antibiotic use and allows healthcare practitioners and policymakers to audit outpatient prescribing patterns with regard to total and subgroup-specific antibiotic use in paediatric age groups and German regions.Some limitations have to be taken into consideration. Firstly, as this study was based on antibiotics prescribed to the population covered by SHI, prescribing patterns in the population with private insurance, representing ca 13% of German inhabitants, remain unknown. Secondly, prescriptions issued by dentists were not included in the study. Antibiotic prescriptions by dentists account for ca 8–9% of outpatient antibiotic prescriptions for patients of all ages. Nevertheless, we assume that systemic antibiotic treatment by dentists is very rare in paediatric care. Finally, compliance with the dispensed antibiotic prescriptions cannot be assessed on the basis of claims data.As in other European countries, considerable reductions in antibiotic prescription rates during the last decade indicate a change towards more judicious patterns of antibiotic use in German outpatient paediatric care. However, as antibiotic use in German children is still ca 70% higher than among their Norwegian and Dutch peers, there is still room for further reduction. Intra-country variation of prescription rates underline the need for regionally targeted interventions. In addition, compared with other European countries, prescribing of second- and third-generation cephalosporins remains alarmingly high and suggests frequent first-line use of these substances in common respiratory infections, thereby contradicting recommendations by German guidelines.


A primary concern of conventional Portland cement concrete (PCC) is associated with the massive amount of global cement and natural coarse aggregates (NCA) consumption, which causes depletion of natural resources on the one hand and ecological problems on the other. As a result, the concept of green concrete (GC), by replacing cement with supplementary cementitious materials (SCMs) such as ground granulated blast furnace slag (GGBFS), fly ash (FA), silica fume (SF), and metakaolin (MK), or replacing NCA with recycled coarse aggregates, can play an essential role in addressing the environmental threat of PCC. Currently, there is a growing body of literature that emphasizes the importance of implementing GC in concrete applications. Therefore, this paper has conducted a systematic literature review through the peer-reviewed literature database Scopus. A total of 114 papers were reviewed that cover the following areas: (1) sustainability benefits of GC, (2) mechanical behavior of GC in terms of compressive strength, (3) durability properties of GC under several environmental exposures, (4) structural performance of GC in large-scale reinforced beams under shear and flexure, and (5) analytical investigation that compares the GC shear capacities of previously tested beams with major design codes and proposed models. Based on this review, the reader will be able to select the optimum replacement level of cement with one of the SCMs to achieve a certain concrete strength range that would suit a certain concrete application. Also, the analysis of durability performance revealed that the addition of SCMs is not recommended in concrete exposed to a higher temperature than 400 °C. Moreover, combining GGBFS with FA in a concrete mix was noticed to be superior to PCC in terms of long-term resistance to sulfate attack. The single most striking observation to emerge from the data comparison of the experimentally tested beams with the available concrete shear design equations is that the beams having up to 70% of FA as a replacement to OPC or up to 100% of RCA as a replacement to NCA were conservatively predicted by the equations of Japan Society of Civil Engineers (JSCE-1997), the American Concrete Institute (ACI 318-19), and the Canadian Standards Association (CSA-A23.3-14). With the increasing risks of climate change and the depletion of natural resources due to their utilization in the construction industry, sustainability has gained wide importance and the term circular economy (CE) has emerged as one of the most important factors leading to sustainable development . In contEvidence suggests that the increasing population growth rate is among the most important factors for urban expansion . Recentl3) into (CaO + CO2) [2 emissions due to the growing worldwide demand for concrete [5 to 5 × 105 tons [From a construction perspective, the Portland cement concrete (PCC) is recognized as the most important material that is widely used in different structural applications with abundant raw material. Annually, more than six billion tons of concrete are produced globally, which are equivalent to 1 ton/capita on the planet ,6. PreviO + CO2) ,10. The O + CO2) ,11,12. Fconcrete . Meanwhiconcrete ,14. More105 tons . In Turk105 tons  also sta105 tons .2 consumption with improved compressive strength and fracture properties of concrete [Coupled with the cement issue is the tremendous worldwide construction and demolition (C&D) wastes originated from the demolition and reconstruction of old structures, which creates another source of environmental burdens. It has previously been observed that annually, over 500 million tons of C&D wastes are generated worldwide . More reconcrete .Discuss the sustainability benefits of GC on the environment, then provide an overview discussion of the most prominent findings concerned with the mechanical properties of GC in terms of compressive strength.Investigate the durability performance of GC under different harsh environmental exposures and then discuss the structural findings on shear and flexural behavior of large-scale reinforced GC beams.Collect all shear behavior studies that partially incorporate RCA or SCMs to replace NCA or OPC respectively, and then analytically compare their concrete shear capacities with available design codes and proposed shear equations.Knowing that PCC production is one of the leading causes of global warming and that there are extensive efforts worldwide to achieve a sustainable environment, this study aims to contribute to the growing research area of GC by conducting a comprehensive review on the sustainability, strength, and durability properties of GC to check for its feasibility as an eco-friendly and structural material instead of the PCC. The GC in this study will be limited to concrete that incorporates RCA as a replacement to the NCA, and either GGBFS, FA, SF, or metakaolin (MK) as a replacement to the OPC. This review paper will allow the user to select the recommended GC constituents that would suit for either low- or high-strength applications by determining the strength ranges either above or below 40 MPa obtained from several studies available in the Scopus database at a certain age, replacement level of cement with one of the SCMs, and water binder (W/b) ratio. Also, this paper will give insights into GC performance in terms of elevated temperature, sulfate attack, chloride ion penetration, and freezing and thawing exposures. Furthermore, this study will analytically illustrate the accuracy of the available design codes and guidelines in predicting the experimental shear capacities of the previously tested GC beams. Therefore, it is intended from this review study to reach for the following:The flow chart of the review process is shown in Worldwide, waste is a growing public health concern. However, recognizing it as a potential source of raw material for the industry would enhance the resource efficiency, because following such a strategy could establish a CE system, by which the materials loops will be closed. Thus, minimizing natural resources depletion, reducing carbon footprint, and eliminating wastes ,34,35,36In the history of sustainable development, the GC has been thought of as a key factor in improving the three sustainability pillars: environmental, economic, and social . This is2 emissions, the case of EAF S showed only minor improvement, while it showed a very big improvement in Eutrophication. Gursel et al. [2-eq/m3, it emerged from their analysis that the mix with 40% OPC, 40% FA, 15% RHA, and 5% limestone flour showed the lowest GWP of 284 kg CO2-eq/m3 without considerable effect on the compressive strength. This finding was also supported by Thomas [2-eq/m3, the replacement of OPC with 25% FA in one mix, and 40% GGBFS in another mix, have shown a 15% and 22% reduction in carbon footprint, respectively. In comparison to cement production, less than a tenth of the carbon footprint is induced from the GGBFS production, with less than a fifth of the energy required to produce cement [To date, several studies have conducted a comparative life cycle assessment (LCA) between PCC and GC. For example, Knoeri et al.  analyzedl et al.  investigy Thomas , where ay Thomas  to be 26e cement . In a ree cement , the OPCe cement  was carrIn this section, the compressive strength properties of GC, which incorporate industrial SCMs such as GGBFS, FA, SF, or MK as one of its ingredients to replace the OPC, will be studied and analyzed. Most of the collected compression tests in this section were done on 100 mm × 200 mm cylinders and a few of the remaining were 150 mm × 300 mm cylinders, 100 mm cubes, and 150 mm cubes.The slag is a by-product produced during the manufacturing process of steel . It is mThe results of compressive, flexural, and split tensile strengths for several studies incorporating the GGBFS at different percentages in concrete are presented in 2 availability forms at later ages [2 as a hydrated lime [3 of SP was incorporated at a 0.28 W/b ratio. Whereas at 28 and 90 days, comparable and higher strength were obtained at the 60% replacement level.The lower strength of GGBFS concrete at early ages was mainly attributed to the slow pozzolanic reaction of GGBFS, which depends on the calcium hydroxide Ca(OH)ter ages . Throughter ages . To enhated lime ,59. Althted lime  revealedAt 7 days, the GGBFS addition resulted in a lower strength compared to the concrete without GGBFS, as indicated in At 7 days, concrete strength of the range 20 to 35 MPa can be achieved when W/b is in the range of 0.42 to 0.5 and when the replacement ratio of GGBFS is ranging from 20% to 60% a.At 7 days, concrete strength of the range 40 to 60 MPa and 60 to 80 MPa can be achieved when W/b is ranging from 0.3 to 0.4 and 0.28 to 0.3 respectively, and when the replacement ratio of GGBFS is ranging from 20% to 60% a.The 28- and 90-day tests pointed out more gain in the GGBFS concrete than the control concrete, therefore most of the GGBFS mixtures showed closer lower strength, whereas some were greater than the control specimens. This could reflect the effect of a secondary pozzolanic reaction d,f.At 28 days, similar or closer strength to the reference concrete was achievable when 20% to 60% of GGBFS was added with a W/b ratio ranging from 0.3 to 0.42 d.At 28 days, concrete strength of the range 20 to 35 MPa can be achieved when W/b = 0.5 with a replacement ratio of GGBFS ranging from 20% to 80% c.At 28 days, concrete strength of the range 40 to 60 MPa can be achieved when W/b is of the range 0.3 to 0.4 and when the replacement ratio of GGBFS is ranging from 20% to 80% c.At 90 days, the compressive strength for all concrete mixtures with different GGBFS% and W/b ratios exceeded 40 MPa, except for 80% of the GGBFS mixture at a W/b ratio of 0.5 e.The ratio of mean GGBFS concrete compressive strength to the 100% OPC concrete compressive strength reaction , but witreaction . It was reaction .2 that reduces the porosity of both the transition zone and the matrix [The increase in strength when cement was partially replaced with FA is attributed to the re-crystallized calcium carbonate and the creation of additional (C-S-H) gel in the cementitious matrix, which was formed by the interaction between FA and Ca(OH)e matrix . Also, te matrix .At 7 days, the FA addition resulted in a lower strength compared to the concrete without FA, however similar or closer strength was achievable when 10% to 15% of FA was added with a W/b ratio ranging from 0.3 to 0.4 b.At 7 days, concrete strength of the range 20 to 35 MPa can be achieved when W/b is in the range of 0.4 to 0.55 and when the replacement ratio of FA is ranging from 10% to 30% a.At 7 days, concrete strength of the range 40 to 60 MPa can be achieved when W/b is ranging from 0.24 to 0.35 and when the replacement ratio of FA is ranging from 10% to 45% a.Similar to GGBFS concrete, the 28-day tests of FA concrete were observed to show more gain in strength than the control concrete, therefore most of the FA mixtures showed closer lower strength and few were greater than the control specimens, except for those mixtures having greater than 40% FA and W/b ratio from 0.4 to 0.6, where no evident enhancement in strength was recorded d.At 28 days, similar or closer strength to the reference concrete was achievable when 10% to 25% of FA was added with a W/b ratio ranging from 0.24 to 0.35 d.At 28 days, concrete strength of the range 20 to 35 MPa can be achieved with W/b of the range 0.5 to 0.6 or 0.24 to 0.45, with a replacement ratio of FA ranging from 10% to 30% or 40% to 60%, respectively c.At 28 days, a higher strength grade of the range 40 to 60 MPa and 60 to 80 MPa can be achieved when W/b is of the range 0.27 to 0.4 and 0.24 to 0.36 and when the replacement ratio of FA is ranging from 10% to 55% and 10% to 40%, respectively c.At 90 days, the FA mixtures exhibited more gain in strength than the 0% FA mixtures. This could reflect the effect of secondary pozzolanic reaction, which produces a higher rate of strength gaining in the long term f.The ratio of mean 2 resulting from the hydration of cement [From the previous findings of GGBFS and FA, the 7- and 28-day strengths were reduced compared to the control specimens without GGBFS or FA, whereas comparable or higher strengths were achieved at later ages of 56 and 90 days. In contrast, the early age strengths at and after 7 days have shown a clear enhancement over the control concrete when cement was partially replaced with SF. This was attributed to the smaller size particle of SF than the GGBFS and FA, which leads to an increase in the pozzolanic reaction between SiOf cement ,94,95,96f cement ,97.Unlike GGBFS and FA, the SF addition resulted in approximately a similar and, in most cases, a higher compressive strength compared to the concrete without SF at 7 days b.At 7 days, concrete strength of the range 20 to 35 MPa can be achieved when W/b is in the range of 0.36 to 0.57 and when the replacement ratio of SF is ranging from 5% to 20% a.At 7 days, concrete strength of the range 40 to 60 MPa can be achieved when W/b is ranging from 0.3 to 0.5 and when the replacement ratio of SF is ranging from 5% to 15% a.The 28-day tests resulted in a higher gain in strength in the SF concrete than the control concrete. Therefore, all the SF mixtures showed greater strength than the control specimens d.At 28 days, most of the compressive strength values were >40 MPa. High-strength grades of the range 40 to 60 MPa and 60 to 90 MPa can be achieved when W/b is of the range 0.35 to 0.5 and 0.26 to 0.4 and when the replacement ratio of SF is ranging from 5% to 20% and 5% to 25%, respectively c.At 90 days, the SF mixtures continue to increase in strength beyond 100 MPa for 10% to 20% of SF concrete with a W/b ratio of 0.27 to 0.3 e.The ratio of mean , which caused much higher pozzolanic activity [Different studies that partially substituted the OPC with MK are provided in -S-H gel . Moreoveactivity .Similar to SF, the MK addition revealed higher early compressive strength than the concrete without MK at 7 days. However, lower strength was obtained when replacing cement by 30% of MK at W/b of 0.32 to 0.36 b.At 7 days, most of the compressive strength values were >40 MPa. This clearly illustrates the high efficiency of MK in attaining high-strength values at early ages b.At 7 days, concrete strength of the range 40 to 60 MPa can be achieved when W/b is ranging from 0.32 to 0.5 and when the replacement ratio of MK is ranging from 10% to 30% a.The 28-day tests have shown more strength gain in the MK concrete than at 7 days. High strength grades of the range 60 to 80 MPa can be achieved when W/b is of the range 0.3 to 0.36 and when the replacement ratio of MK is ranging from 10% to 20% c.At 28 days, high strength grades of the range 80 to 100 MPa can be achieved when W/b is of the range 0.27 to 0.33 and when the replacement ratio of MK is 5% to 15%, respectively c.At 90 days, the MK mixtures continue to increase in strength beyond 100 MPa for 5% to 20% of MK with a W/b ratio of 0.27 to 0.3 e.Even at 28 d and 90 Based on the ratios of mean  in concrete, the carbonation depth was higher than that of the control mix (with no FA and SF) at all ages of the test from 7 to 56 days. When assessing the sulfuric acid attack of 2% acid solution for 56 days, the authors found a 20% reduction in compressive strength of mortar specimens with 15% MK or SF compared to the control mix. Kim et al.  investigHossain and Lachemi  replacedBerndt  studied −12 to 4.7 × 10−12 and 3.2 × 10−12 m/s2, respectively. For concrete with 10% SF, the chloride diffusion coefficient was reduced to 5.6 × 10−12 m/s2. In addition, the 10% and 20% FA concrete enhanced the electrical resistivity from 8.4 kΩ cm in the control mix to 30 and 50 kΩ cm, respectively. However, the 10% and 20% SF concrete resulted in the most significant enhancement with 54 and 231 kΩ cm respectively, where kΩ refers to kilo-ohms. Moreover, the final absorption of water was reduced by 20% and 39% when 10% of FA and 10% of SF was incorporated in concrete, respectively.Sabet et al.  measuredChousidis et al.  employed2 concentration chamber with 65% relative humidity and a temperature of 20 °C. In comparison to concrete with 30% of FA, the incorporation of 3% of SNPs in a 30% FA concrete has reduced the carbonation depth and the sulfate attack by 73% and 39% respectively, while a 35% and a 30% reduction was observed with the incorporation of 6% SF, respectively.Singh et al.  examinedWang et al.  investigAs discussed in the previous sections, the compressive strength of GC has been analyzed by many studies; however, only a limited number of studies were published on its structural behavior. For example, Yoo et al.  evaluateOn the other hand, the shear behavior of RC beams when 50% of OPC was replaced by FA was studied by Rao et al. . Their eCentral to the entire discipline of sustainable construction is the concept of utilizing RCA in RC structures. In China, the RCA concrete was successfully implemented at various pavements and building structures . Hoffmanl et al.  observedl et al.  preparedl et al.  undertakThe available RC design codes; in the design process of an RC beam; specify certain limits on the flexural reinforcement quantity to resist the applied moment first, and to ensure a gradual flexural failure second. However, this is not the case for failure under shear, which usually behaves in a brittle manner with little or without prior warning. Consequently, it is important to analytically investigate the ability of major RC design codes in predicting the experimental concrete shear capacity  of the range 40 to 60 MPa and 60 to 80 MPa can be achieved when W/b ranges are 0.27 to 0.4 and 0.24 to 0.36 and when the replacement levels of FA are 10% to 55% and 10% to 40%, respectively.At the age of 28 days, high strength grades of the range 40 to 60 MPa and 60 to 90 MPa were achieved when W/b is of the range 0.35 to 0.5 and 0.26 to 0.4 and when the replacement ratio of SF is ranging from 5% to 20% and 5% to 25%, respectively.For concrete with MK, the 28-day strength of 60 to 80 MPa was achieved at W/b of 0.3 to 0.36 and with a replacement level in the range of 10% to 20%. At lower W/b of 0.27 to 0.33, the strength range of 80 to 100 MPa was achieved at replacement levels of 5% to 15%, respectively.At elevated temperatures higher than 400 °C, the concrete mixes with either GGBFS, FA, or SF demonstrated a sharp reduction in compressive strength.The sorptivity in pozzolanic cement pastes is remarkably lower than that in Portland cement paste.The long-term resistance to sulfate attack of concrete that combines GGBFS and FA was observed to be superior to the CC mix and high-volume FA concrete mix. Also, the former mix experienced less change in weight.The carbonation depth was shown to increase with the increased content of SCMs, and regardless of SCM type in concrete, the carbonation depth was higher than that of the control mix (with no SCM).The incorporation of silica nanoparticles (SNPs) could result in a significant reduction in the carbonation depth and the sulfate attack.Although the RCA concrete had a more permeable structure than the NCA concrete, the incorporation of FA, GGBFS, or SF can lead to a significant enhancement in the chloride ion penetration resistance.The concrete shear strength models of JSCE-1997 , ACI 318Among all models, the model of Xu et al.  revealedIn this review, the sustainability benefits of GC were discussed first, then its mechanical properties when incorporating GGBFS, FA, SF, or MK as a partially replacing material for cement were analyzed at different replacement levels, different ages, and different W/b ratios in terms of compressive strength. The durability properties of GC were discussed under different environmental exposures. Following this, the structural behavior of GC in large-scale RC beams was analyzed and their concrete shear capacities were compared analytically to the available design codes, such as JSCE-1997 , ACI 318Continued efforts are needed to determine the stress-strain behavior of GC to account for the required design considerations. In addition, further research could also be conducted to determine the GC behavior in large-scale specimens such as beams and slabs under shear and flexure, to develop an understanding of how the combination of GC, bars, and stirrups can create a system that is functional and safe. Another important aspect of research that might produce striking findings is to investigate the bond efficiency of GC with the conventional steel or with fiber-reinforced polymer (FRP) bars. On a wider level, there is a need for a holistic, detailed, and accurate social, economic, and environmental sustainability analysis of GC that considers all stages of GC product from cradle to grave. Finally, we believe that our research will serve as a base for analyzing other types of substitutes in GC, such as agricultural and municipal wastes.


Over the years the growth and health of food-producing animals have been enhanced by the use of antibiotics. These have helped reduce on-farm mortalities, lower incidences of diseases and more importantly improve productivity. Generally, the utilization of antibiotics in feed has been reevaluated since bacterial pathogens have established and shared a variety of antibiotic resistance mechanisms that can easily be spread within microbial communities. Multiple countries have introduced bans or severe restrictions on the non-therapeutic use of antibiotics. This has therefore warranted the urgent need for alternatives. Africa is facing its own challenges as it has been reported to be one of the continents with the highest number of foodborne diseases with approximately 91 million related diseases and 137,000 death per annum. Stakeholder and policy direction has been put in place to curb this escalation; however, the problem persists. The use of alternatives has been recommended and some successfully used in other countries as well as Africa, including pro- and prebiotics and phytochemicals. This then leads to the core aim of this review which is to (1) determine the extent to which antimicrobial-resistant pathogens have affected Africa, (2) assess the current measures put in place by Africa to reduces antimicrobial resistance and finally (3) explore the alternative use of antibiotics in poultry production. Improved sanitary conditions and farm biosecurity are important alternatives that could be adopted by farmers instead of depending on antibiotic drugs for disease control and prevention. The use of antibiotics in the poultry sector is mainly for treatment, prophylaxis and growth promotion. In many parts of the world, food-producing animals are given antibiotics daily to make them grow faster and prevent diseases . This trAcinetobacter spp., Escherichia coli, Klebsiella spp. and Salmonella spp. are some of the microorganisms that are extremely resistant to existing antibiotics [Escherichia coli, Salmonella spp., and Campylobacter spp. are some of the main bacteria that cause diseases in poultry. According to the WHO antibiotics such as fluoroquinolones used in agricultural animals have resulted in the development of ciprofloxacin-resistant Salmonella, Campylobacter and E.coli. which contributed to human infections that were difficult to treat [Campylobacter spp. are prevalent in South African poultry products and pose a threat to human health [In 2018, Africa Centres for Disease Control and Prevention (Africa CDC) developed a framework for antimicrobial resistance in Africa. Africa CDC is an agency of African Union (AU) that helps member states to detect, prevent, control and respond to diseases in Africa . WHO decto treat . Campylon health . It can n health . AntibioThere are many international programs and platforms that have been developed to address the antimicrobial resistance issue. Programs such as antibiotic stewardship, therapeutic drug committee can be used as a standard measure for collecting and comparing drug utilization patterns within and between countries ,12. InteStaphylococcus aureus ST398 has been identified in poultry and other agricultural animals and the transmission of this strain from animals to humans has been recognized [campylobacter strain was discovered in the small-scale and commercial poultry farms in the province of Kwa-Zulu Natal, South Africa [Animals that are repeatedly exposed to small quantities of antibiotics can lead to the development of selective pressure amongst the microbes within the animal. The methicillin resistant cognized . Antibioh Africa .International meat and livestock trade are some of the factors that can contribute to the spread of resistant strains and genetic determinants . Meat anAfrica produces fewer antibiotics as compared to other continents . NonetheStaphylococcus aureus from various poultry meat products in South Africa. Twenty-one percent of the isolates selected for sensitivity testing were methicillin-resistant strains [Namibia is one of the first countries in Africa to ban the routine use of antimicrobials in cattle . The Sou strains .Campylobacter jejuni is likely to be influenced by using antibiotic in both healthy and sick animals in poultry farms [K. pneumonia in free-range chickens, which had a high level of resistance towards antibiotics ampicillin, nalidixic acid, tetracycline, and trimethoprim [Salmonella, Aeromonas, Shigella, Campylobacter and Yersinia retail broilers in South Africa [South Africa is one of the countries that are using antibiotics in food-producing animals . The poury farms . Accordiry farms . Bester ry farms . Moreovery farms . Withdraethoprim . Similarh Africa . In anoth Africa  has spech Africa ,33.One health approach concept simply emphasizes that health of environment, animals and people are connected . This coSalmonella spp. to the antibiotic in the African continent. The table gives a summary of only 10 African states that have ad-hoc surveillance and monitoring programs of antimicrobial at their local institutions or respective farms. Most of the Salmonella strains were resistant to tetracycline.Clostridium perfringens control making pathogens attack more likely. A study by Cardinal et al. found that the withdrawal of antibiotics growth promoters from the diet of broilers increased the cost of production, which will eventually increase the price tag for poultry meat [The use of antibiotics is known to improve chicken health and result in weight gain. Although it comes with a cost, none the less their removal will have consequences in animal production. Cowieson and Kluenter, believe that the addition of antibiotics in animal generates substantial increases in feed conversion ratio and weight gain up to 4% . This imtry meat . On the try meat . The protry meat . AlternaEscherichia coli [The emergence of antibiotic-resistant bacteria in the environment is a global threat to the public. The rapid spread of multiple antibiotic resistance microbes in the environment is the main concern considering the low investment in developing new antibiotics. The wastewater treatment plants are regarded as a threat to public health simply because the three-stage treatment process is insufficient to remove all the pharmaceutical residues. The wastewater treatment plants serve as carriers and transmitters of the antibiotic-resistance border between humans and the environment. Wastewater from hospitals, households and poultry farms waste contains antibiotic-resistance bacterial of animal and human origin . A studyhia coli . The washia coli . Pseudomonas species were prevalent in chlorinated municipal wastewater [Pseudomonas aeruginosa that was isolated from the environmental and clinical origin in the Benin City of Nigeria was 100% resistant to cefuroxime and amoxicillin [Most rivers are considered sources of antibiotic pollution. Residues from farms and human environment may contain antibiotic-resistant genes and antibiotic substance that can contaminate the environment . The emestewater . The prestewater . An intexicillin .The presence of enteric bacterial and their resistance to the antibiotic in the environment at Kakamega town in Kenya is a challenge that can cause a health hazard to the public . In KenySalmonella, E. coli and ultimately change gastrointestinal microbiota [Since the use of antibiotics may have a positive influence on poultry performance, excessive use as growth promoters harms human health. However, discontinuation of antibiotics affects the performance of the poultry. Some researchers argue that the use of antibiotics to improve animal performance through increased growth, and improved feed efficiency, reduces costs of meat, eggs, in other words, the consequence of banning the antibiotics will increase the cost of the animal products. It is a grim challenge which needs to be approached with a delicate balance to ensure safety and optimal performance. Researchers are looking for alternative substitutes for antibiotics in poultry production , such ascrobiota . Nutrients that are proposed to have prebiotic potential include fructans, oligofructose and inulin, fructooligosaccharides, galactan, galactooligosaccharides, resistant starch, pectin, fiber components, milk oligosaccharides ,66. BactThe prebiotics helps to prevent the colonization of the digestive system with pathogens by creating unfavorable condition like altering the pH of intestinal content. Bifidobacterium, lactobacillus which is found in the digestive system has Manase enzyme. They selectively bind manna oligosaccharides only for harmful bacteria which normally do not have this enzyme . The effBacillus, Enterococcus, Lactobacillus, Pediococcus and Streptococcus. It is not only bacteria that are used as probiotics; yeast and fungi have been used, as have strains of Saccharomyces cerevisiae and Kluyveromyces. Care should be taken as other bacteria such as enterococcus could participate in the spread of antibiotic resistance and some like bacillus cereus strains have the capacity to produce toxins [Probiotics are “live strains of strictly selected microorganisms which when administered in adequate amount confer a health benefit on the host” . Probiote toxins .9 colony forming units (CFU/KG) of feed. Other risk factors should be considered when mixing probiotics. The water should not contain any disinfectant or chlorine. After mixing the water should be administered within 6–12 h. Before administering probiotics, if animals were on antibiotic treatment, it is highly recommended that the treatment be withdrawn 24–48 h before administering probiotic [The dose recommendation for most of the probiotic strains is 10robiotic . Probiotrobiotic . Lactobacillus sporogenes (100 mg/kg feed) increased body weight and improved feed conversion ration [lactobacilli spp. in laying hens feed increased egg production and feed efficiency [Broilers that were given n ration . The addficiency . Moreoveficiency . Notwithficiency . In 2019ficiency . Table 2Enzymes as feed additive are produced from fungi and bacteria fermentation are used for maximization of feed conversion. Enzymes such as endo-b-1-4-xylanases and b-1-3, 1-4-glucanases are commonly used with wheat and barley diets of broiler chickens for the improvement of digestibility . FurtherPlant extracts also known as phytobiotics has been shown to be one alternative for antibiotics because of their antimicrobial, anti-inflammatory, antioxidant and antiparasitic activities, and they have been used successfully in poultry production for many years ,95. The In African countries plant extracts from aromatic spices , pungent spices , and herbs spices . Has received increased attention over antibiotics because they are cheaper and naturally available, and they have shown to improve poultry production and health status Organic acids are also part of an effective alternative for antibiotics because of the significant role of reducing pH in the gut of poultry chickens. Reduce pH has been reported to results in improved nutrient utilization. Improved nutrient utilization is because of organic acids also being able to acidify the GIT environment which result in the activeness of protease enzyme. Moreover, they have been reported to be good at fighting against pathogenic bacteria . OrganicThe most commonly known used organic acids are acetic, formic, butyric and propionic acid (simple monocarboxylic acids), malic, lactic and tartaric acids . In poultry, the use of these organic acids has shown to play an important role in digestion especially in diets with poor protein quality. Diet with poor protein quality results in more indigestible protein reaching GIT which end up with high protein fermentation . High prBoth in developed and developing countries, foodborne infections continue to be an extensive and expanding public-health challenge. A report from the WHO estimated that 70% of diarrheal cases originate from bacterially infected foods. Hence, alternatives are sought to antibiotic application in food animals in order to effectively manage bacterial infections both in human and veterinary practice. Current research on alternatives to antibiotic use in food animals is slow, especially in the African continents.. Use of these drugs in humans and animals results in healthier and more prolific animal production. However, the evolution of antibiotic-resistant bacteria is probably linked with the use of these drugs such that high antibiotic utilization corresponds to greater and faster emergence of antimicrobial-resistant bacterial strains. Finally, improved sanitary farm conditions, as well as the maintenance of farm biosecurity, are important alternatives that could be adopted by farmers instead of depending on antibiotic drugs for disease control and prevention. These would essentially serve as a means of preventing the entry and dissemination of disease amongst animals. The available alternatives  to antibiotics have a potential role in lowering dependency on the existing antimicrobial substances. Failure to implement the WHO antimicrobial usage recommendations could deteriorate the situation and intensify the burden of diseases or increase mortality rate in Africa and other continents. Therefore, CDC Africa could assist in ensuring that its member states adopt the available alternatives to antibiotics.


Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory disorder characterized by specific pathologic findings and often, but not in all cases, elevated serum IgG4 concentration. Although it can virtually involve every organ system, cases involving the gastrointestinal tract and especially gastric mass lesions have rarely been reported.A 45-year-old man, who was incidentally discovered asymptomatic subepithelial tumor (SET), by endoscopy, on the greater curvature of the upper gastric body, was referred to our hospital for further evaluation.The patient was postoperatively diagnosed with IgG4-RD by histopathologic results.The patient underwent laparoscopic wedge resection.The patient is presently followed up annually in our clinic and had no problems and showed no signs of recurrence in examination.We reported a rare case of IgG4-RD presenting as a gastric SET. The first line treatment of IgG4-RD is glucocorticoid administration. However, because pathologic examination is challenging owing to the lesion location, preoperative diagnosis is difficult and may lead to unnecessary gastric resection. Thus, using alternative preoperative diagnostic methods such as endoscopic ultrasound-guided fine-needle biopsy or the biopsy unroofing technique could spare the patient from unnecessary surgical treatment. In 2001, Hamano et al first reported autoimmune pancreatitis exhibiting high serum IgG4 concentration termed “sclerosing pancreatitis,” and in 2003, Kamisawa et al proposed a novel clinicopathological entity using the term IgG4-RD.Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory disorder characterized by specific pathologic findings such as dense lymphoplasmacytic infiltration of IgG4-positive plasma cells, storiform fibrosis, obstructive phlebitis, and often, but not in all cases, elevated serum IgG4 concentrations. Diagnosis of IgG4-RD can be confirmed by serological, imaging, and histopathological findings. It can virtually involve every organ system: the pancreas, biliary tree, kidneys, retroperitoneum, prostate, aorta, breast, lymph nodes, thyroid, salivary glands, lungs, pericardium, and skin.,5–12 The pancreas is the most commonly involved organ; however, cases involving the gastrointestinal tract in particular, cases of gastric subepithelial tumor (SET) caused by IgG4-RD have been rarely reported.Although the pathogenesis of the disease remains unproven, type 2 T-helper cell immune response and regulatory T-cell activation have been suggested to be associated with IgG4-RD.Here, we present a rare case of IgG4-RD in the stomach that was diagnosed as SET by endoscopy. Written informed consent was obtained from the patient for the publication of this manuscript and accompanying images.2A 45-year-old man, who was diagnosed with gastric SET detected on endoscopy during a routine medical examination, was referred to our hospital in August 2016 for further evaluation. He was symptom-free and presented no specific abdominal symptoms such as pain, vomiting, heartburn, dysphagia, or change in bowel habits. He had no history of medication or family history of malignant disease or autoimmune disorder.3; hemoglobin level, 14.3 g/dL; and platelet count, 226,000/mm3. His liver function tests were normal. Serum IgG4 or other immunoglobulin levels were not measured because there was no reason to suspect IgG4-RD at that time.In the physical examination, his blood pressure was 110/70 mmHg and heart rate was 80 bpm. The abdomen was soft and flat, and no palpable mass was observed. His laboratory results were normal for the following parameters: leucocyte count, 8900/mmEndoscopy with endoscopic ultrasonography (EUS) was performed. In endoscopic vision, a 3 × 3 cm fixed, round, hard mucosal lesion was detected on the greater curvature of the upper gastric body Fig. . EndoscoTM iDrive purple 60 mm . The postoperative course was uneventful, and the patient was discharged on the fourth postoperative day.Laparoscopic wedge resection was performed using Endo GIAHistopathological examination of the lesion revealed a tan whitish-colored firm mass, measuring 3 × 2.8 cm, protruding from the submucosa and subserosa. On cut section, it appeared white-gray in color Fig. . MicroscThe patient is presently followed up annually in our clinic. In April 2019, the latest follow-up date, the patient did not have any problems and showed no signs of recurrence on endoscopy and abdominal CT examination.3,13 The most common features of this disease include swelling of the involved organ, obliterative phlebitis, elevated serum IgG4 concentration, and IgG4-positive plasma cell infiltration. IgG4 is the least abundant IgG in healthy individuals and typically constitutes under 5% of the total serum IgG. However, high serum IgG4 concentration is not used as a single marker for disease diagnosis as high levels of IgG4 can also be observed in allergic conditions such as allergy, asthma, and eczema.Here, we reported the case of an asymptomatic man with IgG4-RD presenting as a gastric mass, which was surgically resected but could have been conservatively treated had it been diagnosed preoperatively. IgG4-RD is a multi-organ immune-mediated disease that mimics many malignant, infectious, and inflammatory disorders. This condition links many disorders previously regarded as isolated to single organs such as autoimmune pancreatitis, retroperitoneal fibrosis, Riedel's thyroiditis, and Mikulicz's disease. In the present case, the first and third criteria were used to diagnose the patient with probable IgG4-RD because of the lack of serum IgG4 examination.Therefore, IgG4-RD is usually diagnosed based on histopathology. The comprehensive diagnostic criteria for IgG4-RD are divided into three categories: 1) diffuse or localized swelling or masses in single or multiple organs; 2) elevated serum IgG4 concentrations >135 mg/dL, and 3) histopathological findings including marked lymphocyte and plasmacytic infiltration and fibrosis, infiltration of IgG4-positive plasma cells in a ratio of IgG4-positive plasma cells/IgG-positive plasma cell >40%, and >10 IgG4-positive plasma cells/HPF. Patients who fulfil all three criteria have a definite diagnosis of IgG4-RD, those who fulfil the first and third criteria have a probable diagnosis, and those who fulfil the first and second criteria have a possible diagnosis. Lately, few cases were reported of IgG4-RD in the stomach presenting as a gastric ulcer or mass. Seo et al reviewed six cases of IgG4-RD presenting as a gastric mass, including their own case. In most reported cases, the lesion is surgically resected because of misdiagnosis. In fact, the first line treatment of IgG4-RD is glucocorticoid administration and if needed, administration of glucocorticoid-sparing agents such as azathioprine, mycophenolate mofetil, or methotrexate.,9,13 The prognosis of IgG4-RD appears to be good over the short-term with steroid therapy.Shinji et al first reported IgG4-RD involving the stomach in 2004.–20 Although gastric wedge resection is not a radical surgery, it can cause complications such as deformity, which in turn could provoke symptoms such as dyspepsia or gastroesophageal reflux disease. The main limitation of this study is the lack of a serum immunoglobulin test, even when diagnosed postoperatively. Thus, only a probable diagnosis was made in this case.However, IgG4-RD presenting as gastric SET is difficult to diagnose clinically because of its rarity and difficulty to confirm the pathological results without surgery. The pathogenic tissue is usually located on the submucosal layer or even lower; therefore, diagnosis with endoscopic biopsy forceps is difficult. Furthermore, high tumor mobility makes it hard to approach. For these reasons, if gastric submucosal tumors cannot be distinguished with high confidence, despite the use of EUS, most guidelines strongly recommend resection, especially for tumors larger than 2 cm.In conclusion, we reported a rare case of IgG4-RD presenting as a gastric SET. Although the diagnosis of the disease in this case was surgically confirmed, medical treatment such as oral glucocorticoid administration would have been a better option had the disease been diagnosed preoperatively. This case illustrates that an IgG4-RD diagnosis should be considered in the case of gastric masses, and performing EUS-guided fine-needle biopsy or the biopsy unroofing technique could be an option to avoid unnecessary surgical treatment.www.editage.com) for English language editing.The authors would like to thank Editage (Conceptualization: Hee Seok Moon, Eaum Seok Lee.Supervision: Hee Seok Moon, Jae Ho Park, Ju Seok Kim, Sun Hyung Kang, Eaum Seok Lee, Seok Hyun Kim, Jae Kyu Sung, Byung Seok Lee.Validation: Hyun Yong Jeong.Writing – original draft: Min Ji Cho.Writing – review & editing: Min Ji Cho, Hyeon Seok Lee.


Acquired Immune Deficiency Syndrome (AIDS) has become one of the most severe public health issues and nowadays around 38 million people are living with the human immunodeficiency virus (HIV). Ensuring healthy lives and promoting well-being is one of 17 United Nations Sustainable Development Goals. Here, we used the Markov chain matrix and geospatial clustering to comprehensively quantify the trends of the AIDS epidemic at the provincial administrate level in the mainland of China from 2005 to 2017. The Geographically Weighted Regression (GWR) model was further adopted to explore four groups of potential influencing factors  of the AIDS incidence rate in 2017 and their spatially distributed patterns. Results showed that the AIDS prevalence in southeastern China had been dominant and become prevalent in the past decade. The AIDS intensity level had been increasing between 2008 and 2011 but been gradually decreasing afterward. The analysis of the Markov chain matrix indicated that the AIDS epidemic has been generally in control on the Chinese mainland. The economic development was closely related to the rate of AIDS incidence on the Chinese mainland. The GWR result further suggested that medical care and the education effects on AIDS incidence rate can vary with different regions, but significant conclusions cannot be directly demonstrated. Our findings contribute an analytical framework of understanding AIDS epidemic trends and spatial variability of potential underlying factors throughout a complex extent to customize scientific prevention. Human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) has become one of the most severe public health issues since the first cases of AIDS were identified in 1981 . Due to As a branch of epidemiology, spatial epidemiology has developed rapidly in recent years. With spatial statistical methods, spatial epidemiology improves the understanding of disease from qualitative level to quantitative level, by analyzing geographically indexed health data related to demography, environment, behavior, socio-economy, genetics, etc. ,7. SuppoSpatial analysis has become increasingly common in HIV/AIDS-related research, specifically for the geographic distribution assessment . For insFor truly controlling HIV and directly reducing the number of new infections, an understanding of the spatial distribution needs to be combined with an investigation of potential influencing factors. Smith et al.  found thThe discipline of the spatial and temporal analysis of the AIDS incidence and its influencing factors are not uniform. So far, the research mainly focuses on the analysis of AIDS spatial distribution, especially in South Africa ,13,24,25To fill the gap, this study collected the AIDS incidence data on Chinese mainland from 2005 to 2017 to study the spatial distribution characteristics and influencing factors of the AIDS epidemic, so as to provide a theoretical basis for policymakers to customize scientific prevention and control policies. The study focused on AIDS incidence, i.e., the body’s immune system is badly damaged because of the HIV virus. The paper is organized as follows. After the description of the research data and sources, www.phsciencedata.cn). The AIDS prevalence in China for the period 2005–2017 was investigated, considering the data resource consistency and the fact that AIDS was drawn attention by the Chinese government around the year 2005 [AIDS incidence data was acquired from the Data Center of China Public Health Science  for our Markov chain illustrated in the ijm, I = j) is a smooth transition, i.e., the state of AIDS intensity level is stable for one Markov chain process. The transition probabilities in the upper-right corner  refers to an upward transition, and the transition probabilities in the lower-left corner  refers to a downward transition. If the state of AIDS intensity level is stable for one Markov chain process, we assume that the AIDS intensity for the corresponding province was in control. An upward transition for the AIDS intensity level indicates that the AIDS epidemic situation was serious and a download transition for the AIDS intensity level indicates that the AIDS epidemic situation was reduced. The calculation formula of each element ijm in the matrix is:i AIDS intensity level  transforming to a type j AIDS intensity level; There are 4 × 4 transition probabilities  was conducted. Spatial autocorrelation can be used to describe the spatial difference between the spatial units and their adjacent units. Moran Index was proposed in 1950  and haven is the number of the samples; i and its neighborhood: High-High (H-H), High-Low (H-L), Low-High (L-H), and Low-Low (L-L) aggregation [As a measurement of spatial associations at local level, the Local Indicators of Spatial Autocorrelations (LISA) statistics allow us to detect AIDS clusters on the assumption that the local AIDS spatial pattern was not randomly distributed. Local Moran’s Index tests the agglomeration and difference chrematistics of AIDS incidence rates in different spatial locations. The Local Moran’s I is defined as:l object . It rangregation . Local Mregation .Here, AIDS incidence clusters were defined as geographic areas in which AIDS prevalence was disproportionately higher compared to neighboring areas. Hot-cold Spot Analysis (Getis-Ord Gi * statistics)  was adopkth independent variable of sampling point i. Instead of remaining the same everywhere, i, kth independent variable at location i.Unlike OLS, GWR is a spatial regression method to model spatial variation in the relationship between dependent and independent variables and estimates the influence degree . By calcPrior to modeling, correlation analyses were conducted among the potential explanatory variables  to assesThe overall change trend AIDS incidence rate at the national level for the mainland of China from 2005 to 2017 can be divided into four stages . The firThe spatial distribution of AIDS incidence rates at the provincial scale was first visualized intuitively in ArcGIS10.2 software  and z scores are positive , indicating that the AIDS incidence rates had become spatially clustered. Especially, between 2011 and 2017, the global Moran’s I index raised rapidly from −0.114 to 0.312, indicating a growing spatial clustering tendency of the AIDS incidence rate for the enter study area.To further measure the spatial correlation and difference of AIDS incidence rates for each provincial unit and surrounding units, we used the GeoDa software to calculate Moran’s I scatter plots diagrams for five representative time points, as mentioned in p-value for each unit determined the high or low values. Based on that, the spatial patterns of the Hot-Cold Spots were illustrated in The Getis-Ord Gi * statistics results at the provincial level were interpreted in the ArcGIS environment. Similar to the interpretation of the Global Moran’s I statistics, the resultant Z score, and For the variables in four groups , a comprehensive variable was extracted as the influencing factor of each group of potential explanatory variables. The eigenvalues were 3.79, 1.76, 4.52 and 2.73 respectively, and coefficients were 2.00, 1.46, 2.24 and 1.73 respectively . Taking For the four variables from different perspectives of socio-economy, the standard errors of coefficients for medical care and education were much higher than those of the other factors. The ratios of the corresponding coefficient value and the standard error were higher than 2.5 for most of the observations , which iThe economy had a negative effect on the AIDS incidence rate for most of the areas in the mainland of China. Relatively absolute higher estimated coefficients were observed in western China (<−0.1) and especially southwestern China (<−0.2). It is noted that the economy level is relatively low in these regions, however, the degree of impacts was relatively large, and attention should also be paid to these areas. It indicated that a lower level of economic development would lead to a decrease in the capacity to prevent and control the AIDS epidemic. An unexpected finding of a slightly positive effect of the economy on the AIDS incidence rate was exhibited in Northeast China. Since the coefficients were near 0, and they were much lower than the coefficients in other regions, the effect of the economy on the AIDS incidence rate is hard to predict. GWR also revealed a strong spatial heterogeneity in the relationships of traffic and transportation and AIDS incidence rate. The more developed, the more the AIDS spread prevalent. The effects of traffic and transportation on the AIDS incidence rate were positive and the coefficient decreased from the west to the east, indicating that the western region is greatly influenced by the traffic and transportation development.Our results provide a comprehensive quantification of subnational AIDS epidemic trends on the Chinese mainland with geospatial analytical methods. Our study first addressed the spatial variations and time evaluations in AIDS incidence rate and intensity levels. Around the year 2004, the Chinese government and local authorities carried out a series of HIV infection checks and blood tests, to intervene in further HIV transmission through blood . Thus, tFinding on the Markov chain matrix analysis indicated that the high AIDS intensity level area and low AIDS intensity level area tend to maintain the original state in the next period. In other words, these areas had a higher probability of maintaining a high-intensity level in the next coming years and vice versa. Besides, the transfer probability between adjacent two levels is greater than that of cross-level, indicating the space-time transition and evolution had been gradual rather than jumping. Our spatial agglomeration study also demonstrated that a large proportion of AIDS patients had been concentrated in a small number of administrative units with strong spatial correlation. Our analysis highlights this favorable situation to efficiently target resources and interventions for bringing AIDS and HIV infection under control on the Chinese mainland.Overall, the analysis of GWR revealed that the economy was most closely related to the AIDS incidence rate on the Chinese mainland. First, the economy was shown to be an essential and foremost factor that influences the AIDS incidence pattern. The regression coefficients of economic development were negative except for northeast China, which is consistent with the previous finding related to the spatial distribution of AIDS and main socio-economic driving factors in China . In soutIn terms of the traffic and transportation, the effect was more prevalent in western China than in eastern China, as evidenced by the higher estimated coefficients. The traffic and transportation in this study generally refers to population flow throughout the transportation networks. Even through the transportation by itself do not have a cause on AIDS, since the HIV transmission is different from respiratory epidemics. However, the GWR analysis indicated that the in transnational migrants accompanied by population flow due to trade cooperation and travel, and drug trafficking have a cause on AIDS. Previous study indicated that more than 60% of foreign AIDS cases travel to and from the border between Yunnan and Myanmar, which has also contributed to the spread of AIDS in the region . The freMedical care and education level have been widely identified as important determinants of AIDS prevention at different scales ,16,36,38Previous studies also found that high-educated individuals should be targeted for AIDS prevention  and thatIn this study, we used a spatially statistical method to explore the spatial distribution of the AIDS epidemic and its influencing factors on the mainland of China from 2005 to 2017. This study first provided a comprehensive quantification of AIDS epidemic trends at the provincial administrate level. According to the analyses of the AIDS intensity level mapping and the spatial clustering, we found that the prevalence of AIDS in southeastern China has remained high in the past decade. The period between 2008 and 2011 witnessed the apparent increasingly severe tendency of the AIDS incidence level, which gradually decreased afterward. Markov chain matrix analysis indicated that AIDS intensity level transfer probability between adjacent two levels was greater than that of cross-level, suggesting the AIDS epidemic has been generally in control on the Chinese mainland. In terms of influencing factors of the AIDS incidence, the economic development closely related to the AIDS incidence rate on the Chinese mainland. The GWR result further showed that the effects of medical care and education on the AIDS incidence rate differed from different regions. Our study contributes to an analytical framework of understanding AIDS epidemic trends and spatial variability of the underlying factors throughout a complex area to customize scientific prevention. In future research, the fine-scale spatiotemporal investigation of AIDS prevalence based on GIS and information related to the spatial variability of relationships can be a fundamental method to precise AIDS interventions.


Cheirogaleus medius) housed at the Duke Lemur Center (DLC) could hibernate, by subjecting 8 individuals to husbandry conditions more in accord with those in Madagascar, including alternating photoperiods, low ambient temperatures, and food restriction. All dwarf lemurs displayed daily and multiday torpor bouts, including bouts lasting ~ 11 days. Ambient temperature was the greatest predictor of torpor bout duration, and food ingestion and night length also played a role. Unlike their wild counterparts, who rarely leave their hibernacula and do not feed during hibernation, DLC dwarf lemurs sporadically moved and ate. While demonstrating that captive dwarf lemurs are physiologically capable of hibernation, we argue that facilitating their hibernation serves both husbandry and research goals: first, it enables lemurs to express the biphasic phenotypes (fattening and fat depletion) that are characteristic of their wild conspecifics; second, by “renaturalizing” dwarf lemurs in captivity, they will emerge a better model for understanding both metabolic extremes in primates generally and metabolic disorders in humans specifically.In nature, photoperiod signals environmental seasonality and is a strong selective “zeitgeber” that synchronizes biological rhythms. For animals facing seasonal environmental challenges and energetic bottlenecks, daily torpor and hibernation are two metabolic strategies that can save energy. In the wild, the dwarf lemurs of Madagascar are obligate hibernators, hibernating between 3 and 7 months a year. In captivity, however, dwarf lemurs generally express torpor for periods far shorter than the hibernation season in Madagascar. We investigated whether fat-tailed dwarf lemurs ( However, in the absence of a changing photoperiod and the co-varying environmental conditions, e.g., under captive conditions, seasonal physiological responses expressed by animals vary depending on whether circannual clocks are endogenous or responsive to environmental input2.Seasonal environmental variation can impose energetic challenges on animals at predictable times of the year. Thus, it is not surprising that animals evolved mechanisms to tune reproduction, metabolic strategies, and other life-history traits to photoperiod5. Daily torpor generally involves shallow metabolic depression  that lasts for a few hours per day. Thus, daily torpor users can continue to forage during the active period of the day, while saving energy during the daily resting phase6. Daily torpor expression can occur throughout the year and irrespective of ambient temperature5. Daily torpor users may show evidence of fat deposits to fuel metabolism, but this is not a precondition for torpor expression, and some species enter torpor opportunistically without showing any evidence of fattening . A more extreme example of metabolic depression is displayed by animals expressing multiday torpor, i.e., hibernation, which depress metabolism for weeks at a time. Hibernation is often seasonal, restricted to the wintertime, and is characterized both by deep metabolic depression and body temperatures that approximate ambient temperature5. Torpor bouts during hibernation are interspersed by periods of energetically expensive arousals5. Hibernators require prior accumulation of fat deposits to sustain months-long periods without feeding (unless they use food caches). Hibernators can, however, show short torpor bouts (less than 24 h) at the beginning and end of the hibernation season, or at high ambient temperatures, which may give the appearance of daily torpor4. As more studies of “non-holartic”8 heterotherms are accrued, however, it is becoming evident that daily torpor users and hibernators do not always fall into clear-cut categories11. In fact, there is growing evidence of heterotherms from all major phylogenetic lineages displaying extraordinary physiological flexibility: Marsupials like honey possums (Diprotodontia) can express daily torpor while significantly reducing body temperature to near ambient12; pygmy possums (Diprotodontia) can facultatively hibernate in the wild13; and hedgehogs (Eulipotyphla)14 and elephant shrews (Afrotheria)15 use daily torpor but can sporadically display prolonged torpor. One of the most impressive examples of heterothermic flexibility is shown by the common tenrec of Madagascar (Afrotheria) that can hibernate at an unprecedented range of body temperatures (from 12 to 28 °C) without undergoing sporadic arousals17.Daily torpor and hibernation, two metabolic strategies employed by animals that face periodic environmental challenges such as food shortages, show physiologically distinctive patterns and are potentially regulated by different mechanismsMicrocebus griseorufus, undergoing daily torpor, prolonged torpor, or hibernation, depending on their fat storage and environmental conditions9. The dwarf lemurs , phylogenetically related to mouse lemurs, are considered to be the only primates that express hibernation obligatorily: all species of Cheirogaleus for which we have data (7 out of 9 species) hibernate in the wild, displaying hibernation bouts that can last for a few days up to several months depending on hibernacula conditions18. The hibernation season lasts, depending on the species and individuals, between 3 and 7 months a year22. Prior to hibernation, all dwarf lemurs show significant fattening primarily concentrated in their tails. Fat deposits are then used to fuel metabolism during the hibernation season24.Extreme heterothermic variation is also exemplified by Madagascar’s mouse lemurs (40–80 g), with members of the same species, e.g., 25. No evidence of multiday torpor was reported. Similarly, in Brunoy, France, two captive dwarf lemurs subjected to more naturalistic conditions of alternating photoperiod and temperature variation between 24 and 30 °C (“summer” season) and 17 and 30 °C (“winter” season) failed to show a hibernation phase26. Dwarf lemurs did reduce activity levels between July and August and experienced a period of fattening prior to the expected “winter” season. The caveat, however, was that ambient temperature settings did not allow the dwarf lemurs to further reduce body temperature or depress metabolism (but see Petter-Rousseaux’s pers. comm. cited in26 on mention of hibernation in dwarf lemurs subjected to 12 °C). Contemporary work by McCormick27 also failed to confirm metabolic depression consistent with hibernation when oxygen consumption was measured in three dwarf lemurs at the DLC exposed to alternating photoperiod, relatively constant temperature conditions (~ 23 °C), and food ad libitum. Finally, Foerg and Hoffman28 did not find evidence of hibernation in DLC dwarf lemurs, corroborating previous studies. Although dwarf lemurs showed lethargic behavior, including reduced activity, prior to the reproductive season (February–March), some level of activity persisted throughout the study. It is important to note that none of these studies experimented with food restriction, nor did they reduce ambient temperature below 20 °C.Though the case of dwarf lemurs in the wild is a clear-cut example of hibernation, captive dwarf lemurs fail to express hibernation. A pioneer study conducted at the Duke Lemur Center  showed that three fat-tailed dwarf lemurs subjected to constant photoperiodic (LD12/12), temperature, and dietary conditions showed seasonal changes in body mass, but inconsistent activity patterns: between September and December, the lemurs were sometimes lethargic, sometimes active29 showed that at least one dwarf lemur at the DLC decreased metabolic rates consistent with hibernation, but the lemur’s individual torpor bouts did not last longer than 24 h. Recent observations showed that some dwarf lemurs avoided eating for multiple days during the winter season, while maintaining skin temperatures close to cooler ambient temperatures . This study sought to examine the role of temperature and food availability but was challenged by sporadic sampling. Nonetheless, the results suggested that while those factors likely influenced the depth and duration of torpor, they were not essential to its initiation. The data suggested seasonal torpor, leading to hibernation, was the result of an endogenous cycle. This is consistent with the fact that other non-primate hibernators undergo physiological changes in preparation for hibernation, such as fattening, in the absence of environmental cues, suggesting that genetic mechanisms are at play30.More than 20 years have passed since these pioneer studies, and questions still remain as to whether or not dwarf lemurs under captive conditions can express consistent hibernation. Krystal et al.31), which may not facilitate multiday torpor expression. Moreover, food availability may have prevented torpor expression, either directly (by increasing metabolism) and/or indirectly (by increasing disturbance). Alternatively, it is possible that captive breeding and exposure to artificial conditions may hinder the dwarf lemurs’ ability to express hibernation. DLC dwarf lemurs have been captive bred for a minimum of four generations and descend from a few wild individuals brought to the DLC in the 1960s. Other non-primate hibernators that were bred in captivity have shown hypothermia and an inability to arouse from torpor, as well as shorter and less deep torpor bouts compared to their wild counterparts32. That some individuals lose the capacity to hibernate in captivity may suggest that environmental conditions during ontogenetic development are critical to activate the machinery of hibernation32.Available evidence to date is insufficient to confirm whether or not dwarf lemurs under captive conditions can express hibernation comparable to that of their wild counterparts. We argue that a “lack of hibernation” by dwarf lemurs in captivity could be due either to environmental constraints, i.e., conditions that are not conducive to hibernation expression, or biological constraints, i.e., captive-bred dwarf lemurs may have lost their capacity to hibernate. In all previous studies, ambient temperatures were maintained at relatively constant levels around 25 °C  housed at the DLC have the capacity to express hibernation comparable to that of their wild peers33, we subjected them to novel husbandry conditions, including lower ambient temperatures and more restricted food availability than was hitherto practiced . When compared by month, the number of STB was significantly greater in October and November, compared to later months . The number of LTB was greater in November and December compared to other months . The longest individual torpor bouts were observed in January, with the exception of individual “Mo” who was removed from the study before the end of the month.  and long torpor bouts . Indeed, dwarf lemurs were in torpor ~ 70% of the time between October 15 and February 10. STB trended towards being more frequent in males than in females  whereas lemurs spent more time expressing LTB in December and January  , night length (Night_L), food intake (before a torpor bout), and sex on the duration of torpor bouts, we found all variables had a significant effect. Twall was the stronger predictor of torpor duration, with longer bouts occurring at lower temperatures. Night length and food eaten had a similar effect, and sex was the weakest predictor Table .Although ambient temperature had a significant effect on torpor bout duration, there was also individual variation in the expression of torpor under the same temperature conditions. For instance, during a remarkable warm spell in January, the room temperatures increased by ~ 4 °C and remained at this value (~ 18 °C) for about 6 days, followed by a cooling period. During this time, some dwarf lemurs experienced daily torpor (“Au”) whereas others displayed prolonged torpor (“Ra”). Arousal periods, for both individuals, began around the time of light-switch off, corresponding to the “night” phase. For individual “Au,” hours between arousal periods were: 18, 25, 24, 24, 24, 23, and for “Ra”: 44, 27, displaying cyclicity consistent with circadian regulation. All dwarf lemurs, however, experienced a long torpor bout after cooling of the rooms  upon torpor bout duration, e.g., with longer torpor bouts in December compared to November, although the rooms were maintained at similar temperatures. This may suggest that regulatory mechanisms other than temperature-dependent circadian clocks may be at play34.By exposing members of the DLC dwarf lemur colony to low ambient temperatures and a flexible food-restriction regimen, we demonstrate, for the first time, that captive dwarf lemurs are physiologically capable of sustaining months-long hibernation. As documented for their wild counterparts37, which unlike dwarf lemurs, are considered “facultative hibernators”. Although female grey mouse lemurs can experience multi-day torpor bouts in the wild38 they have not been observed to do so in captivity. In captive mouse lemurs, torpor expression is generally restricted to short days, although small daily variations in body temperature can be observed during long days39. Arousal from torpor in mouse lemurs responds to circadian control entrained by photoperiod40. Moreover, food restriction is known to facilitate torpor expression, with longer torpor bouts occurring as food restriction is increased41. The combination of food restriction and low ambient temperature shows the greatest effects in mouse lemurs, inducing the longest torpor bouts37.The individual and synergistic roles of photoperiod, food, and temperature in modulating the expression of torpor have been previously documented in other small-bodied lemurs, the mouse lemurs42. Within the temperature range under which dwarf lemurs can express torpor, there appears to be a temperature threshold above which some critical physiological processes can occur. For instance, above 25 °C there is evidence of REM sleep in dwarf lemurs thermoconforming to ambient temperature, but low amplitude brain activity (no sleep) is recorded below 25 °C43. This temperature baseline may not be exclusive for hibernating lemurs, but for non-primate hibernators as well. Geiser5 (p.R190) argues that the “…duration of torpor bouts in hibernators is strongly temperature-dependent and  at high Ta of ~ 20 to 25 °C they often are < 24 h and superficially appear to be daily torpor…”. This may explain why earlier studies on captive dwarf lemurs all failed to report hibernation expression, because the room temperatures were maintained constant between 20 and 25 °C. This may also explain why individual “Au” showed torpor expression comparable to daily torpor during the “warm” week in January.The relationship between torpor and temperature is complex. Mouse and dwarf lemurs can thermocomform to a great range of ambient temperature without “arousing” from torpor. While hibernating, dwarf lemurs can passively track ambient temperature ranging from ~ 10 to 30 °C daily for weeks and months, making arousals unnecessary44. Alternatively, opportunistic feeding may have allowed individuals to limit torpor expression by acquiring energy from the environment. That males fed more times, expressed short torpor bouts more often, and stayed in torpor fewer hours overall than did females  suggest that feeding may have affected torpor dynamics to a degree. Feeding may have increased the frequency of arousals in males which, in turn, increased their energetic costs resulting in greater body mass loss. The more “active” profile of males is also consistent with the torpor optimization hypothesis: torpor expression should be minimized when there is an energy surplus, because of the potential physiological costs associated with metabolic depression45. Dwarf lemur females, on the other hand, displayed overall longer torpor bouts than did males, and lost less of their fat reserves by the end of the study. These results are predicted by a modified version of the optimization hypothesis, the thrifty-female hypothesis, that accounts for female reproductive burden: females benefit from maintaining body fat deposits after emergence from hibernation to sustain the costs of imminent reproduction47.Unlike wild dwarf lemurs, DLC dwarf lemurs were offered some food during the study and opportunistically ate during the hibernation season. We cannot be certain as to why the dwarf lemurs continued to eat during the study, or whether they, like non-primate hibernators, undergo a remodeling of the intestinal microbiota composition during hibernation48. Notably, dwarf lemurs are obligate hibernators in their natural habitats, and they evolved to experience drastic physiological states, alternating between periods of significant fattening in preparation for hibernation, and depletion of fat stores during the hibernation season. These physiological states likely evolved as a mechanism to cope with the environmental hypervariability that characterizes Madagascar, where yearly dry seasons and stochastic weather events limit the availability and stability of high-quality foods49. For dwarf lemurs, the reproductive season is thus limited to 4–5 months a year, with females having a short gestation period of ~ 2 months. Young dwarf lemurs display relatively fast growth rates during the first 2 months of life, to achieve ecological independence, and begin depositing fat before they attain adult size. Dwarf lemurs do not achieve sexual maturity until they are ~ 2 or 3 years old50. Under captive conditions of constant warm temperature and unrestricted food regimes, however, dwarf lemurs achieve adult size and reproductive maturity within a year and generally experience daily torpor for ~ 3 months52.Although it is tempting to succumb to the idea that torpor expression should be minimized to avoid the associated physiological costs, a question remains as to whether long-term exposure to energy surplus may result in the development of metabolic disorders in organisms that evolved mechanisms to sustain hibernation in the first place53.Modulating hibernation expression in dwarf lemurs at the DLC has critical implications for husbandry, as well as research. Although it is difficult to attribute detrimental health effects in the DLC colony to the lack of torpor expression, non-hibernating captive dwarf lemurs do show irregular patterns of body mass gains and losses that do not necessarily correspond to the expected periods of fattening and fasting. At the extreme, some dwarf lemurs maintain consistent weight and significant fat reserves year-round. One can assume that development of diabetes and cataracts that are present in some aged dwarf lemurs at the DLC may be, in part, the result of long accumulation of physiological mismatches under captive conditions. It could be further speculated that the presence of ectopic excess fat retained by dwarf lemurs during the active season may carry long-term physiological costs, as it is associated with the development of metabolic syndrome in non-hibernators54. A “renaturalized” captive dwarf lemur population will set the stage for future investigations of the mechanisms underlying hibernation expression and its regulation, for example exploring protective mechanisms that allow dwarf lemurs to tolerate spikes in sugar or lipid metabolism without showing signs of illness20. This is particularly promising as dwarf lemurs, the closest relatives to humans that hibernate, are emerging as excellent animal models for understanding the mechanisms of metabolic extremes and their implications for ageing and metabolic disorders, such as diabetes and metabolic syndrome, that are known all too frequently in humans.Thus, exposure to contrasting environmental conditions, leading to the expression of seasonal phenotypes may, in fact, help maintain a healthy dwarf lemur population in captivity, if hibernation is expressed in moderationThe dwarf lemurs were housed in two separate temperature-controlled rooms, four individuals per room between September 30 (Room A) or October 1 (Room B) 2019 to February 14, 2020 Fig. . Each dwFor acclimatization purposes, when dwarf lemurs were transferred to the rooms, they were maintained at ~ 25 °C for a week (between October 1–7), and at ~ 20 °C the following week (between October 7–14). From October 15 until February 10, the temperature was maintained between 10 and 15 °C. Despite attempts to keep temperatures relatively constant, there were daily fluctuations, sometimes exceeding 4 °C (e.g. January 17th). On February 10, when the study ended, room temperatures were increased to ~ 20 °C to begin acclimatization of the individuals to “summer” temperatures. The temperature of each room  was recorded hourly by an ibutton attached to a wall, located halfway between the door and the opposite end of the room, and at breast height (the fours wooden boxes were located at either side of the ibutton and at higher or lower positions). Another ibutton was located inside an empty box located inside one of the rooms. When comparing the “inside the box” temperature against “wall” temperature, differences were less than 1 °C and considered negligible. Thus, we used Twall for the purposes of comparisons with skin temperature (Tsk) from radiocollars. Room A was consistently colder than Room B during the study period by ~ 1 °C Table . Water wWe employed a shifting photoperiod, from “winter”-like days (shortest 9:30 h light) to “summer”-like days (longest 14:30 h light). Daylight increased from January to June and decreased from July to December, following a northern hemisphere schedule, i.e., opposite to Madagascar. Daylight changes were programmed to occur in 30 min periods every other week. At the time of transfer to the temperature-controlled rooms, on September 30 and October 1, the dwarf lemurs experienced shortening photoperiods until January 13, when daylight began to increase . We kept data from “Mo” in the analysis, however, because her behavior had been considered normal until her removal. Critical values for body mass were calculated, on an individual basis, as the lowest weight ever recorded per lemur in adulthood minus 10%. These values ranged between 140 and 158 g.We selected eight adult dwarf lemurs, four females and four males aged between 6 and 15 years, from the DLC colony to participate in the torpor study  was measured using a measuring tape. Because handling individuals and removing them from nest boxes generally triggered an arousal, we tried to time weighing sessions with “natural” arousals, which we could detect by checking dwarf lemurs’ Tsk values displayed on the receiver. Due to Institutional regulations, however, we could only delay weighing session up to 5 days from the scheduled date. We documented whether individuals were “in torpor” or “euthermic” at the time of weighing. Data included in the analysis were collected between October 15, 2019 and February 10, 2020. This corresponds to the time periods when the temperature of the rooms was maintained between ~ 10 and 15 °C.The dwarf lemurs were fitted with small external radio collars with variable pulse rate transmitters . Pulse rates varied according to temperature of the external sensor, which was in contact with the dwarf lemurs’ skin around the neck (Tsk). Those pulse rates were automatically converted to temperature values in degrees Celsius by a receiver with datalogger . The receiver, which was placed outside of the rooms, scanned transmitters continuously and stored the transmitters’ temperatures hourly. Radio collars were fitted to be gently pressed against the dwarf lemurs’ necks to provide skin temperature estimates. The tighter the contact  the better the approximation of body temperature. Although Tsk is only a proxy for body temperature, we could clearly differentiate “euthermic” vs. “torpor” states. Originally, we set 29 °C or less as the temperature threshold for torpor. After visual inspection of the data and observations of dwarf lemurs during daily checks, we determined that 22.5 °C or less was a more conservative value, so as not to overestimate torpor expression. For instance, individuals were seen outside of the wood box, moving around at Tsk 24 °C. This relatively low temperature value for activity may be explained by transmitter’s sensor picking up dwarf lemur’s skin temperature (presumably higher at the time of moving around), but also ambient temperature (between 10 and 15 °C).Every morning at ~ 8:00, the authors downloaded Tsk data from the previous 24 h for all dwarf lemurs to a laptop computer. Hours in “torpor” (< 22.5 °C) vs. “euthermic” (≥ 22.5 °C) were counted and reported on the individuals’ data sheets. If the sum of the “euthermic” hours since the last feeding event reached 24 h, food was prepared and placed inside the individual’s enclosure along with daily water replacement.For the first 2 weeks of the study (October 1 and 15), the dwarf lemurs were offered a standard “winter” daily diet, consisting of fruit/veggie mix and Old-World monkey chow per approved standard DLC husbandry protocols . Once the rooms were cooled down to ~ 15 °C, we put in place a food restriction protocol: the dwarf lemurs were offered the standard “winter” diet if they accumulated a minimum of 24 h of activity since the last time food was offered. Each morning, food bowls were removed and inspected for leftovers. Scores were noted on each individual’s datasheet as follows: 3 = all food left, 2 = half food left, 1 = little food left, 0 = nothing left. For the purpose of the analysis, we lumped scores 1–3 as “food eaten” and score 0 as “food uneaten”.All research and experimental protocols used in this study were approved by the Duke University Institutional Animal Care and Use Committee, under protocol A263-17-12, and the Duke Lemur Center Research Committee (MO-11-18-6). These protocols followed guidelines established by the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health.55). We ran a linear mixed model using the glmmADMB package (version 0.8.3.356) and R software program (version 3.3.357) in Rstudio (version 1.1.46358), using log-transformed torpor bouts (in hours) as response variable (Torpor bouts were categorized as “short torpor bouts” (STB) if they lasted 24 h or less, and “long torpor bouts” (LTB) if they were longer than 24 h. We also calculated average Tsk and average Twall during torpor bouts and recorded whether torpor bouts started soon after food had been ingested . We ran non-parametric tests, Wilcoxon and Steel–Dwass, to compare body mass and tail base circumference between sexes, and torpor bout frequency across months (October to February), respectively, and we calculated Pearson correlation coefficients between body mass loss (in %) and torpor duration (in hours) or feeding events in JMP (version Pro 15.0.0variable . We usedSupplementary Information.