About 80% of the nearly 2 billion people experiencing psychiatric conditions worldwide do not have access to quality, affordable mental health care. In Africa, there are 0.004 psychiatrists per 10,000 people, with the shortage exacerbated by a limited number of postgraduate psychiatry training opportunities. As of 2018, there were only two psychiatrists in Liberia.This paper aims to offer a framework for developing postgraduate  psychiatry training in resource-constrained settings to disseminate best practices and lessons learned. This article describes the approach to developing the formal global academic partnership that supported the initiation of Liberia’s first postgraduate psychiatry training program in July 2019.Authors describe strengths, challenges, and opportunities for improvement in the planning and initiation stages of the postgraduate program. Key strengths of the program planning process include: (1) collaboration with a coalition of local and national stakeholders committed to improving mental health care in Liberia; (2) early procurement of quality video conferencing equipment and internet service to facilitate remote learning and broaden access to digital materials; and (3) leveraging of intra-continental partnerships for subspecialty training. Challenges experienced include: (1) navigating the intricacies of local political and administrative processes; (2) recruiting candidates to a medical specialty with historically lower salaries; and (3) the added burden placed on the limited number of local specialists. Identified opportunities include building a monitoring, evaluation, and learning (MEL) framework, further diversifying subspecialty areas of psychiatric and neurological training, and obtaining full accreditation of the postgraduate psychiatry program through the West African College of Physicians (WACP).The successful launch of the postgraduate psychiatry training program in Liberia is attributed to several factors, including a long-standing academic collaboration of over 10 years and support for mental health capacity-building efforts at national and local levels. Thou+ people . In Afri+ people . The sho+ people . While mIn the West African nation of Liberia, there has long been only one psychiatrist for a population of nearly 5 million. Though the country once had a healthcare system that was the envy of its neighbors, Liberia’s devastating 14 years civil conflict buckled the entire healthcare system by its end in 2003. The country suffered mass destruction to its infrastructure, including its businesses, schools, health facilities, and government. Thousands faced extreme brutality, including shootings, beatings, or rape by soldiers. During the conflict, most perpetrators of gender-based sexual violence were fighting forces; however, after the conflict, perpetrators were ex-combatants, community or family members, teachers, and male partners . In 2007During the conflict, Liberia experienced a massive brain drain of health professionals, university faculty, and hospital and medical school administrators who fled the country . By 2014A proven approach to building capacity for specialized mental health care in global settings involves partnerships between academic and/or health institutions in high-income countries (HICs) and similar organizations in low-and middle-income countries (LMICs), known as “twinning” relationships . In traiThe Liberia Psychiatry Residency Program builds on the existing progress of the Government of Liberia in developing medical specialty training programs. In 2013, the national government coordinated efforts with the Ministry of Health to establish postgraduate medical training programs that aligned with the National Health Policy and Plan. The Liberia College of Physicians and Surgeons (LCPS) was thus created to train qualified physicians as specialists to improve and strengthen the health care delivery system across the country. In 2016, faculty from the LCPS and the Boston Medical Center (BMC)/Boston University School of Medicine (BUSM) Department of Psychiatry began a twinning partnership with the shared goal of expanding Liberia’s capacity to provide specialized psychiatric and neurological care. Seven full-time medical specialties, including internal medicine, pediatrics, surgery, OB/GYN, ophthalmology, family medicine, and psychiatry, most of which are supported by donor programs, currently oversee postgraduate training at six teaching hospitals throughout Liberia. Since 2013, the LCPS has enrolled an average of 19 residents per year into their medical specialty programs, except for 2014 when enrollment was halted during the Ebola epidemic. There are currently 62 total residents enrolled in the LCPS’ training programs. The first class of 13 residents graduated in June 2017. To date, 110 doctors have completed postgraduate training through the LCPS and become certified specialists in various disciplines.This article describes the approach to developing the formal global academic partnership that supported the initiation of Liberia’s first postgraduate psychiatry training program in 2019. In addition, we describe strengths, challenges, and opportunities for improvement in the planning and initiation stages of the postgraduate program .2.2.1.Faculty from the LCPS and the BMC/BUSM Department of Psychiatry have a long history of working together to build capacity for quality mental health care in Liberia. In 2009, the Government of Liberia’s Ministry of Health & Social Welfare invited Dr. David C. Henderson and his Boston-based research team to consult on the country’s first comprehensive national mental health policy, which aimed to address the unique needs of the people of Liberia due to the social disruptions, societal disorganization, and varied war-related traumatic experiences , 22. ComMembers of the Liberia-Boston collaboration applied findings from the needs assessment to develop the Liberia Mental Health Policy in 2009 , 21–26. 2.2.In September 2018, members of the Boston-based research team visited partners in Monrovia, Liberia to conduct a situation analysis following significant changes in leadership in the country’s government. The site visit consisted of meetings with a wide range of local stakeholders: the Ministries of Health and Education; leaders of the University of Liberia (UL) and the UL A.M. Dogliotti (AMD) College of Medicine; staff at E.S. Grant Mental Health Hospital, Liberia’s only tertiary psychiatric hospital; and staff at Saint Benedict Menni Health Centre (commonly referred to as the Step Down Unit). Each meeting focused on understanding stakeholder practices, priorities, and commitment to mental health services. These discussions and tours of local resource-constrained mental health facilities led to a deeper understanding of the need for specialist mental health services, the availability of medications, the prevalence of mental health conditions, and potential challenges that would inform the development of Liberia’s first postgraduate psychiatry training program.2.3.After completing the initial site visit and identifying collaborative goals between each institution, members of the Liberia-Boston collaboration set up a memorandum of understanding (MOU) in February 2019 that described the purpose and scope of the global partnership. The MOU delineated clear roles and responsibilities for each partner with specific short, medium, and long-term goals. Short-term goals for the first year of the program included: (1) development and approval of a postgraduate psychiatry program curriculum from the West African College of Physicians (WACP) ; (2) pro3.The LCPS Psychiatry Residency Program curriculum was modeled after the WACP guidelines for postgraduate psychiatry training and is based on the progressive accomplishment of core competencies over 36 months. In addition to adult and public health psychiatry, the curriculum integrates strong clinical training in child and adolescent psychiatry (CAP). CAP skills are argued to be more generalizable to all ages compared to those of general psychiatrists , which iClinical training for the postgraduate psychiatry program takes place primarily at the E.S. Grant Mental Health Hospital—an 80-bed psychiatric hospital that also provides outpatient services —and JohnThe program is also conducted with support from the local Saint Benedict Menni Health Centre , which serves as a clinical training site specific to women’s mental health to promote reintegration into the community post-treatment. Saint Benedict Menni Health Centre belongs to the Archdiocese of Monrovia and is managed by Sisters Hospitallers, located in Spain. Sisters Hospitallers originally arrived in Liberia in 1966 to offer services for orphaned and abandoned children, and has since grown to offer 24 h services in general outpatient care, maternal and child health, communicable diseases, pharmaceuticals, etc. Saint Benedict Menni Health Centre also collaborates with other health institutions in Liberia to optimize available health resources and reach the greatest number of people with mental illness. Among its priority objectives is training students in managing mental pathologies through pharmacotherapy and occupational therapy, respecting each person’s condition, and emphasizing the institutional values of Sisters Hospitallers.Located in Durban, South Africa, the University of KwaZulu-Natal (UKZN) Nelson R. Mandela School of Clinical Medicine serves as an intra-continental partner and clinical rotation site for the residents to receive specialty training in child and adolescent and community psychiatry. Local Nigerian institutions including the University College Hospital (UCH) in Ibadan and the Neuropsychiatric Hospital in Aro also serve as intra-continental partner sites for specialty training in addiction, child and adolescent, forensic, and geriatric psychiatry. Additional partnerships critical to the success of the postgraduate program include international faculty based in Seattle, United States, who supplement supervisory and teaching responsibilities of the two Liberia-based psychiatry faculty. International teaching faculty offer expertise in neurology, child and adolescent psychiatry, and medical education, and are actively engaged in teaching in-country and remotely via weekly video conferencing. International faculty members also collaborate with local psychiatrists to supervise residents and provide training materials that may be adapted to the Liberian context.members. They may also choose to sit for the WACP examination at this time, though this is not a requirement. Members may subsequently complete an additional 24 months of specialized training along with the presentation of results from a major research study to qualify as fellows. Members demonstrate a high standard of psychiatric knowledge, clinical service, and leadership, while fellows have additional expertise in supervision, research, and specialist consultation capable of providing technical input at national and international levels. Completing the fellowship qualifies psychiatry residents to become teaching faculty at the UL AMD College of Medicine and to obtain subspecialty expertise as desired in child and adolescent, addiction, consultation-liaison, geriatric, or forensic psychiatry. As previously noted, the Liberia-Boston collaborative aims to develop a mentored fellowship program focused on faculty development and research to sustain the LCPS’ postgraduate training programs.Within the WACP, graduates of the postgraduate psychiatry program are required to sit for the LCPS examination to qualify as 4.4.1.We identified five major strengths of the LCPS Psychiatry Residency Program, which was launched in July 2019. First, full engagement of and collaboration with local and national stakeholders in pursuing a common goal: to improve mental health care in Liberia. This engagement required significant time investment and relationship-building over 10 years. In order to effectively advocate for resources, buy-in from all stakeholders—educational leaders and local partners alike—was essential . Second,4.2.There were several challenges leading up to the launch of the LCPS Psychiatry Residency Program. First, stakeholder engagement and collaboration was challenging due to frequent changes at different levels in the national government. This meant that relationships and connections needed to be rebuilt and trust reestablished before planning could continue. This process took 10 years. In addition to the frequent changes in national government officials and key stakeholders, navigating the intricacies of the local political and administrative process was difficult. The process underscored the importance of remaining flexible and tolerating ambiguity, which are key competencies when working in resource-constrained settings .Second, program faculty faced difficulties in recruiting candidates for the postgraduate psychiatry program as university salaries are historically lower in the field of psychiatry relative to other medical specialties. Program faculty are working to improve the recruitment process by increasing early exposure to psychiatry in medical school to attract a strong pool of candidates to the postgraduate program.Third, the program placed an added demand on the two in-country psychiatrists to balance providing their psychiatric expertise, educational leadership in curriculum development, and the administrative and advocacy work required to secure resources for the postgraduate program. Members of the Liberia-Boston collaboration continue to meet regularly to strategically maximize existing resources and reduce the administrative burden for the in-country teaching faculty.4.3.As the LCPS Psychiatry Residency Program grows, we have identified short-and long-term opportunities for improvement and expansion. Short-term opportunities include the development of a monitoring, evaluation, and learning (MEL) framework with measurable indicators to track resident progress and ensure residents receive timely and valuable feedback regarding their clinical skills and knowledge. This aligns with the LCPS’ historical culture of learning and adaptation of existing medical specialty training programs. The MEL framework will also include a program evaluation component that will evaluate resident experiences with didactics, clinics, and wards, as well as feedback from program faculty, staff, and other stakeholders. This evaluation will be used to assess and improve curricular offerings, supervision, working environments, and future program planning. Another short-term opportunity identified is diversifying subspecialty areas of psychiatric and neurological training by expanding international faculty collaborations and integrating research mentorship throughout the program.In the long term, the Liberia-Boston collaboration aims to access the necessary equipment and resources to obtain full accreditation of the postgraduate psychiatry program through the WACP. As psychiatrists complete the postgraduate program and enter the workforce, we also aim to expand available clinical services to include psychotherapy and school-based interventions to improve access to and utilization of mental health care services.5.5.1.This paper outlined the strengths, challenges, and opportunities for improvement in developing and initiating Liberia’s first postgraduate psychiatry program . In doinThe successful launch of the postgraduate psychiatry training program in Liberia is attributed to several factors, including a long-standing partnership of over 10 years between faculty at the LCPS in Monrovia, Liberia and at BMC/BUSM in Boston, United States. In addition, mental health capacity-building efforts were supported on a national level and well underway before the postgraduate psychiatry training program launched. This is best demonstrated by the development of Liberia’s first national mental health policy in 2009 and the ensuing 5 years Mental Health Policy and Strategic Plan for Liberia (2016–2021) by the Government of Liberia’s Ministry of Health , where these data have been presented 16–2021, . This paOne major strength of the LCPS Psychiatry Residency Program is the curriculum development adapted from the WACP. This makes it possible for the postgraduate training program to seek accreditation from the regional accreditation body. An advantage of this is that graduates from the program may become involved in the WACP to improve postgraduate psychiatry training in the West African region and strengthen intra-continental collaboration and partnerships. The WACP curriculum is developed by a committee of specialists from all member countries to reflect the knowledge and competencies required of trainees to become effective mental health specialists with the capacity to work in any of its member countries. One of the core faculty of the LCPS Psychiatry Residency Program was trained in Nigeria and completed a fellowship in the WACP Faculty of Psychiatry. By leveraging these intra-continental partnerships, capacity building and knowledge sharing can be more effective and accessible.5.3.Academic medical centers in LMICs and HICs often form educational collaborations to improve healthcare delivery and health outcomes in resource-constrained settings . These pThe Liberia-Boston collaboration is based on a relational model with funding from the Liberian government, similar to TAAPP and the Toronto Addis Ababa Academic Collaboration (TAAAC) , 34. EssSimilar to the challenges faced by the Liberia-Boston collaboration in launching the LCPS Psychiatry Residency Program, TAAAC reported administrative and bureaucratic challenges with local partners, making coordinating joint efforts taxing . Local TFinally, the allure of the West poses a challenge for the LCPS Psychiatry Residency Program that is well documented throughout the literature , 37. In 5.4.This paper presents the process leading up to the establishment of the first postgraduate psychiatry training program in Liberia. By outlining the strengths, challenges, and opportunities for improvement, we hope to provide a framework for other academic medical centers seeking to pursue similar LMIC and HIC collaborations to improve the capacity for mental health care in resource-constrained settings.There are several aspirations for future collaborations and associated constraints to sustained implementation . First, Second, reducing administrative burdens of local faculty must be considered. As part of program development, it is essential to include the role of program coordinators to manage the administrative tasks of running a psychiatry residency program. In fundraising for global mental health programs, donors and stakeholders have traditionally considered “overhead” or indirect costs to be wasteful. However, programs with robust infrastructure including strong leadership, essential administrative support, technology, fundraising processes, financial management, and skills training are more likely to succeed . IdentifThird, as residents graduate from training programs, efforts need to be made to absorb them into the academic medical centers to increase the capacity of local faculty , 34. ThiFourth, subspecialty fellowship programs, particularly in child and adolescent and addiction psychiatry, are greatly needed. Like many African countries, Liberia consists predominantly of people under the age of 25 years, which makes training child and adolescent psychiatrists a desirable goal. There are only two countries in Africa with formal postgraduate training in child and adolescent psychiatry, which presents great potential for future collaborations and expansion of existing postgraduate psychiatry training programs , 42. FurFifth, there is a dire need to strengthen research capacity in resource-constrained settings. For decades, increasing research capacity has been a global health priority as it helps to strengthen health systems , 49. DesThe original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.All authors discussed and collaboratively agreed upon the design, results, analysis, and planning of the manuscript. SG wrote the original draft of the manuscript. MT contributed to the literature review. TO and MO significantly contributed to the writing and reviewing of the manuscript. BH, BO, MD, KH, CB, and DH provided critical revisions to the manuscript. All authors contributed to the article and approved the submitted version.This work was supported by the National Institute of Mental Health (NIMH) Grant Numbers K01MH100428 and T32MH116140. 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This study aims to offer an overview and a longitudinal evaluation of the HomeSafe program implemented in Surrey in 2008 and to assess its effectiveness in mitigating fire-related outcomes. (2) Methods: Data were collected over a 12-year period (2008–2019). Assessed outcomes comprised frequency of fire incidents, residential fires, casualties, functioning smoke alarms, and contained fires. The effectiveness of each initiative was determined by comparing the specific intervention group outcome and the city-wide outcome to the pre-intervention period. (3) Results: This study targeted 120,349 households. HomeSafe achieved overwhelming success in decreasing fire rates (−80%), increasing functioning smoke alarms (+60%), increasing the percentage of contained fires (+94%), and decreasing fire casualties (−40%). The study findings confirm that the three most effective HomeSafe initiatives were firefighters’ visits of households, inspections and installations of smoke alarms, and verifications of fire crew alarms at fire incidents. Some initiatives were less successful, including post-door hangers (+12%) and package distribution (+15%). (4) Conclusions: The HomeSafe program effectively decreased the occurrence and magnitude of residential fires. Lessons learned should be transferred to similar contexts to implement an evidence-based, consistent, and systematic approach to sustainable fire prevention initiatives.  Fire-related mortality and morbidity represent the third leading causes of residential unintentional injuries globally ,2,3. FirResidential fires remain a major health concern, accounting for a high proportion of injuries and deaths globally . The exiTo mitigate the burden of residential fires, several intervention strategies and best practices have been adopted and implemented globally . EvidencInspired by successful fire prevention programs globally , the ‘HoInitial evaluation results demonstrated positive effects of this program over the first few years . BuildinA longitudinal study was conducted to assess the effectiveness of HomeSafe fire prevention initiatives implemented in high-risk fire areas within the city of Surrey, Canada for the 12-year period (2008 to 2019). To identify high-risk fire areas, information was used from the 2016 census of the Canadian population  and the National Fire Information Database  to calculate a risk score for each Dissemination Area : through this initiative, the Surrey Fire Service generated high-risk target areas and grouped them into cohorts (1–7) by geographic proximity a. CohortHomeSafe2 (2011–2017): Through this initiative, seven new cohorts (cohorts 8–14) in high-risk areas were targeted via door-to-door visits by fire crews b. HomeSaTreatment 1: Firefighters conducted door-to-door visits for 500 households within cohort 14.Treatment 2: Home visits were made to 4600 high-risk residents within cohort 13.Treatment 3: Informational door hangers were distributed to 8740 residential properties identified via spatial clustering and outlier analysis.HomeSafe3 (2018–2019): Through this initiative, community volunteers engaged in conducting door-to-door visits and telemarketing  to 4 new cohorts (cohorts 15–18) in high-risk areas c using GData were collected from the HomeSafe initiatives and the Surrey Fire Service for the period from 2008 to 2019. Data prior to HomeSafe were collected using the British Columbia Office of the Fire Commissioner (OFC) and the Surrey Fire Service.To assess the effectiveness of the HomeSafe initiatives, the frequency and severity of residential fires experienced before and after implementing the intervention were compared. To measure the impact of the initiatives, data were compared to residential fire data captured by the British Columbia OFC in the 3 years prior to the implementation of HomesSafe1 (2005–2007).For HomeSafe1, a randomized high-risk cluster control method was adopted to assess fire-related outcomes between the intervention cohorts and randomized control cohorts with equivalent fire risk but with no fire prevention intervention. HomeSafe1 rates were compared between the targeted cohorts and the control group. For HomeSafe2 and HomeSafe3, an Analysis of Variance (ANOVA) was conducted to determine the significance of the between-group effect on fire rates in home visits.The effectiveness of each implemented initiative was determined by comparing the specific intervention group outcome and city-wide outcome during each HomeSafe initiative period to the pre-intervention period. The investigated intervention group outcomes included: (1) residential fire rates (per 1000 dwellings), (2) proportion of functional smoke alarms, and (3) proportion of fires confined to the object of origin (as a proxy to fire severity). The investigated city-wide measures included: (1) fire rates , (2) fire-related injury and death rates , (3) proportion of functioning smoke alarms at the time of residential fire incidents, and (4) proportion of fires confined to the room of origin. Further comparisons included: (1) total number of requested smoke alarm inspections and/or installations, (2) smoke alarm verifications at incidents, and (3) households reached at various events. To prevent any discrepancies, abandoned properties were excluded from the evaluation as they introduce unique challenges and require interventions beyond the scope of this study . This exA total of 120,349 households participated in the 12-year period of the HomeSafe program  initiative led to a 91% reduction in residential fires, with a 50% reduction still apparent 5 years post-intervention. Among the 91 smoke alarm functioning verifications completed by fire crews at residential fire incidents, only 2.2% had post-visit fires . Pre- anThe HomeSafe2 (HS2) initiative demonstrated a positive impact on reducing residential fire rates by 75% with smoke alarm installations by request, and a reduction of 66% where fire crew smoke alarm verifications took place at incidents. There was an increasing trend in the percentage of functional smoke alarms, 61.5%, at locations where smoke alarms were installed, as well as an increase of 6.1% where crews verified the presence of functioning smoke alarms . In contThe HomeSafe3 (HS3) initiative revealed a favorable impact on increasing the rate of functioning smoke alarms from 35% to 100% through home visits by volunteers, as well as the proportion of fires confined to the object of origin (67%). Additionally, this initiative successfully reduced fire rates by 33% for smoke alarm installation upon request and by 87% for verification of smoke alarms by the fire crew at incidents .Over the period of the HomeSafe1 initiative, intervention groups sustained a residential fire each 97.3 and 193.1 days before and after the intervention, respectively, compared to the control group, which experienced a residential fire every 64.1 and 68.8 days pre- and post-intervention, respectively  Table 2Table 2.2  = 5.57, p-value < 0.05 and X2  = 6.61, p-value < 0.02, respectively). The ANOVA demonstrated the impact of in-home visits on the fire rates, resulting in a significant between-group effect F  = 8.31, . Post hoc analysis showed substantial differences in post-intervention fire rates between the intervention and control groups F  = 6.56,   .During HomeSafe2, a 57% decrease in residential fires was reported in the intervention cohorts following the door-to-door visits, in addition to a noticeable rise in the proportion of functional smoke alarms (23%) and residential fires contained within the object of origin (12%) .During HomeSafe3, the residential fire rate in cohorts 15–18 decreased by 80% to reach 0.31 fires per 1000 occupied properties, while the percentage of functional smoke alarms increased by 183% and the residential fires confined to the object of origin after the visit decreased by 33% .During the initial three years of the HomeSafe1 program, successful city-wide outcomes were illustrated by a 34% reduction in residential fires and a 58% reduction in the fire casualty rate, while the number of residential properties with functional smoke alarms increased by 11% and the number of residential fires contained to the object of origin increased by nearly 54% .During HomeSafe2, Surrey City sustained a 22% decrease in residential fires, a 39% increase in functioning smoke alarms , a 20% decrease in fires contained within the room of origin, and a 24% increase in the casualty rate .In the HomeSafe3 period, residential fire rates in the city of Surrey continued to decrease to reach a 26% reduction since HS2 and a 43% reduction since the onset of the HomeSafe1 initiative in 2008. The proportion of functional smoke alarms increased by 130% to reach 56%, with 43% of residential fires contained within the object of origin . The casThis study presents the outcomes of the HomeSafe Program over a period of 12 years and demonstrates the effectiveness of implemented fire interventions in decreasing the occurrence and the impact of residential fires, enhancing fire safety measures, and reducing fire-related injuries and deaths.Throughout the implementation period, HomeSafe achieved considerable success in decreasing fire rates within the city of Surrey by 80%, increasing the presence of operational smoke alarms in residential homes by 60%, improving fire confinement to the initial source by 94%, and, more importantly, decreasing fire casualties by more than 40%. The study findings confirm that the three most effective HomeSafe initiatives were the household visits conducted by on-duty firefighters, smoke alarm inspections and installations upon request, and the validation of smoke alarms by fire crews during fire incidents.Despite the overall success of the HomeSafe program, data showed that some initiatives were more effective than others for the measured outcomes. For instance, outreach initiatives, such as information package drop-offs and door hangers, which lack direct personal contact and informational transactions with household residents, have proven to be less effective at ameliorating fire-related outcomes. As for telemarketing outreach, the data set of contact numbers available was somewhat random and not necessarily aligned with the targeted risk criteria. The post-outreach analysis demonstrated the absence of fire incidents reported in the contacted properties pre- or post-implementation of the initiative. Aligning with existing studies, the evidence from this study further demonstrates that door-to-door visits by firefighters or public safety volunteers served to enhance residents’ safety knowledge through interactive and engaging educational information and to ensure functioning fire alarms were installed in targeted households ,25. ThisAligning with the international literature, this study confirms that households with functioning fire alarms reported remarkably low rates of fire-related injuries and deaths . InstallThe HomeSafe program offers opportunities for lessons learned and presents a series of recommendations for future fire prevention programs, including:Community engagement and government support are key to enhancing safety and reducing residential fires ,15. ActiAs demonstrated in this study, variation in the success of the HomeSafe initiatives was clearly highlighted. Door visits conducted by firefighters, smoke alarm inspection and installation upon request, as well as fire crew validation of smoke alarms at fire incidents were proven effective in raising awareness about fire safety, advising on potential hazards at home, and, consequently, reducing the occurrence and severity of fires. However, initiatives that lacked social interaction opportunities, such as personal contact and dialogue with recipients, were less successful. It is critical to identify which initiative has the potential to succeed and to invest efforts into its proper implementation.To ensure an effective fire safety program, the intervention should target high-risk populations and should regularly update and map the higher-risk neighborhoods . This apOngoing monitoring and evaluation of the fire interventions are crucial to ensure the long-term success of the initiative . To mainImplementing a large-scale program that aims to reach a sizeable proportion of the targeted population can lead to a sustainable decrease in fire-related injury and death rates over decades.To enhance program sustainability, it is important to tailor the intervention based on new protocols associated with any surging pandemic and to address the challenge of maintaining effective program operation while prioritizing the health and safety of crews, volunteers, and residents. Future fire intervention programs should take into consideration the ‘knowing–doing gap’ and the ‘wear-off’ effect  to ensurOne of the major contributing factors to the success of the HomeSafe program is the adoption of a systematic and coherent approach for conducting fire safety campaigns as well as validation and installation of smoke alarms. This approach has shown positive impacts on the visited properties and the entire city. The success of the program reinforces existing research and emphasizes the significance of evidence-based, systematic, and continuing dissemination of fire safety information to residences together with smoke alarm testing and installation services. The mutual benefits of reducing community residential fires and improving firefighters’ jobs with less exposure to fires, the produced smoke’s toxic chemicals, and the associated risk of contracting occupational-related cancers led to more sustainable and consistently monitored fire safety initiatives across the community over time.Synthesized findings from the HomeSafe program can be adopted by policy makers and key stakeholders to inform evidence-based safety regulations and data-driven decisions on resource allocation and fire safety program implementation. Further to supporting policy makers’ decisions, findings from the HomeSafe program can be adopted to benchmark the effectiveness of various fire prevention programs in other regions and to use HomeSafe as a model program to evaluate existing programs and refine and make changes to improve outcomes.The long-term, sustained commitment to the program across the Surrey Fire Service is exceptional. The mutual understanding between fire management and firefighters has led to a cultural shift of incorporating the activities of HomeSafe into regular daily duties. By verifying a working smoke alarm at every residential opportunity, the program becomes sustainable on an ongoing basis. One of the distinguishing features of this program can be explained by the literature on government innovation. While the definition of innovation remains contested , this prUsing a framework of key factors for innovation, it is apparent that this success was due to several organizational, managerial, and cultural conditions. In This study has some strengths and limitations. The systematic and consistent approach adopted to implement the fire intervention represents the major strength of this study. The longitudinal aspect of the HomeSafe initiative, with the fire safety campaigns and smoke alarm testing and installations, constitutes a key strength of the HomeSafe program. This study faces a few challenges and incurs some limitations. One of the main limitations of the HomeSafe initiative is the ability to map neighborhoods that align with the profile of the targeted population while taking into consideration the dynamic environment of the city based on its organization, development, and residents’ socio-economic status. The lack of recent and updated population demographic data hindered the precise identification of high-risk areas for HomeSafe targeting. However, a possible solution for properly identifying high-risk areas would be the implementation of a nearly real-time monitoring system for each initiative and merging it with an up-to-date database of population demographics, as well as city organization and development. Additionally, within each HomeSafe initiative, residents’ demographic data could be collected whenever social interaction with residents is possible. This would further enhance the overall data collection process. Another limitation refers to the spread of the coronavirus pandemic in 2019, which coincided with the implementation of HomeSafe3.This posed a new challenge in maintaining the effective operation of the HomeSafe program without risking the health and safety of residents, fire crews, and community volunteers. Restricted social interaction among residents hindered the promotion of fire safety campaigns for at-risk residents. Existing fire initiatives should adapt to and accommodate the spreading of the pandemic while aligning with protocols and measures for the well-being of individuals. Nonetheless, these obstacles created opportunities for program enhancements that can be explored in future work. Finally, the effectiveness and outcomes of the tax lineup and Surrey Food Bank initiatives were impeded by the challenges encountered in collecting property information during these events.This longitudinal study assessed the effectiveness of several fire safety initiatives implemented through the HomeSafe program and their impacts on enhancing fire safety and reducing fire-related outcomes. The HomeSafe program provides clear evidence on the effectiveness of targeted interactional educational and environmental modification interventions as part of an overall community risk reduction initiative. Future opportunities to interact with the targeted social groups for the promotion of the program and safety outcomes may assist with expanding the message to those who are not picked up in the program delivery areas.


The 6 February 2023 earthquake that struck southern and central Turkey and northern and western Syria had unique drawbacks, such as the occurrence of two strong, destructive earthquakes nine hours apart in multiple and densely populated geographical areas, exposure to unforgiving winter conditions, and increased anxiety and fear due to multiple aftershocks , 2. As oSearch and rescue teams should include medical professionals as an integral part of the team  because It was critical to create a bridge between providers of care in the field taking into account their needs, and the central health authority and its healthcare delivery service in this chaotic environment. This was as important as coordinated search and rescue in the field. Disaster preparedness is a very critical issue and an absolute necessity not only for disaster victims, but also for patients with chronic diseases who require uninterrupted medical care, such as dialysis patients . TherefoTo coordinate activities, a Turkish Earthquake Zone WhatsApp group was established. Council members of the TSPN and pediatric nephrologists working at the hospitals in 10 affected cities were included in the group. Fortunately, our society members working at the earthquake zone were not directly affected by the earthquake. However, there were many damaged hospitals, pediatric wards and HD centers. This group was expanded to include physicians working neighboring the damaged area and finally, those at distant centers who could accept patients from the affected areas.With the contribution of our senior colleagues with a vast experience on disaster medicine, Prof. Dr Lale Sever  and Prof. Dr Mehmet Şükrü Sever , the Basic Guide for Crush Syndrome in Children was adapted from the adult guide and circulated to our members on the same day , 15.Needs in terms of pediatric nephrology personnel, dialysis machines, catheters, dialysis supply and medications were determined.The places where a pediatric nephrologist was needed were determined.We created a list of volunteering pediatric nephrologists willing to offer support in the affected areas. Ten volunteers actively worked in the earthquake zone for a limited time interval of 3–5 days. Some of the pediatric nephrologists were replaced because of or to prevent burnout.Hatay, the most deeply affected city, was visited for supporting volunteer pediatric nephrologists and to determine the needs with close contact with the field. The emergency department, dialysis unit and pediatric ward of the university hospital were investigated. Even though there was damage in different hospital buildings, the dialysis unit was intact and was actively working. The Minister of Health and Minister of Interior Relations visited the Disaster and Emergency Management Coordination Center in Hatay. The current situation was discussed and the importance of uninterrupted search and rescue efforts was emphasized to the government officials.Coordination was ensured with the Disaster and Emergency Management Presidency and MoH officials in order to quickly meet the needs in terms of pediatric nephrologists. Different general directorates of the MoH were contacted to meet the different demands of pediatric nephrologists working in the field.General Directorate of Health Services: HD machines and dialysis supplies , different consumables, medications including antibiotics, bicarbonate, calcium gluconate, and infusion fluids including albumin, were transferred, where necessary.General Directorate of Public Hospitals: centrally pre-set outpatient appointments were cancelled in two big city hospitals accepting too many earthquake victims in order to decrease the workload of pediatric nephrologists in these centers.General Directorate of Personnel: volunteer pediatric nephrologists and pediatricians were assigned to affected areas, dispensations for our colleagues who had been active in the damaged area were arranged to decrease their burden and facilitate their psychological recovery. Additionally, Turkish Psychiatry Society and Psychology Societies worked very actively in the area.This early action facilitated precluding the coordination problem in the region in the first days of the earthquake. Personnel and material needs from the field, including dialysis consumables, which can change every moment were constantly monitored and solved quickly. Immediate transport of volunteers including pediatric nephrologists and pediatricians was arranged by the MoH and was even realized by military helicopters, where necessary. The widespread network of HD units throughout Turkey allowing rapid transfer and rescheduling prevented any interruption in HD treatments of pediatric victims.By cooperation with the Turkish Society of Nephrology, continuity of care was assured by contacting adult nephrologists when necessary, especially in centers without pediatric nephrologists.Meetings were organized in collaboration with Turkish Pediatric Association and İstanbul branch of TSPN .Disasters from the perspective of pediatric nephrologist—9 February 2023Crush syndromeDisaster preparedness in pediatric nephrology centersStudy suggestionsAfter the earthquake—16 February 2023“How should I approach pediatric earthquake victims?”“How should I protect myself as a physician?”Impressions from the fieldIn cooperation with the Turkish Neonatology Association, a guideline was created for the follow-up of newborn babies in earthquakes .A meeting was organized by the European Society for Paediatric Nephrology (ESPN) Disaster Taskforce to help Turkish pediatric nephrologists. Free online registration support for the 55th ESPN Congress which will be held in Vilnius, Lithuania for young Turkish pediatric nephrologists who were on the front lines of the earthquake was suggested by the TSPN, and this was well accepted by ESPN council.Although there were enough resources in terms of dialysis equipment/supply in Turkey, the International Society of Nephrology (ISN) Renal Disaster Relief Task Force and the German Nephrology Association expressed their willingness to provide any kind of dialysis supply. Although there was no need in Turkey, these dialysis supplies were sent to Syria by the ISN Renal Disaster Relief Task Force.Industry, particularly the dialysis industry, helped a lot. Private dialysis center owners opened their doors for free dialysis sessions, and they used their catheters, tubing and all consumables without any restriction.A web-based patient database was created to collect basic patient data . EthicalThe Turkish Society of Nephrology has kidney disaster preparedness plans but pediatricians have not been involved. This is an important shortcoming and should be considered a priority area for the pediatric nephrology community, which requires much more attention and work on it . There mIn this widespread tragic disaster, the TSPN was a part of the national/international collaborative effort to save patients’ lives and to decrease crush injury and resultant acute kidney injury–related morbidity. Even though the amateur effort worked nicely and the Turkish pediatric nephrology community responded well to this tragic event, it was realized once more that well-structured kidney disaster preparedness masterplans and roadmaps with algorithms for pediatric kidney disaster management are essential. Predefined disaster sister hospitals and well-structured kidney disaster action plans including the establishment of kidney disaster teams and immediate mobility of medical personnel to the affected areas should be organized. Kidney disaster management should be incorporated into the pediatric nephrology fellowship curriculum, and even the medical school curriculum. Reliable data collection during these unforeseen events and careful analysis and interpretation of the results are of particular importance for managing future events.


Sulfate often behaves conservatively in the oxygenatedenvironmentsbut serves as an electron acceptor for microbial respiration in awide range of natural and engineered systems where oxygen is depleted.As a ubiquitous anaerobic dissimilatory pathway, therefore, microbialreduction of sulfate to sulfide has been of continuing interest inthe field of microbiology, ecology, biochemistry, and geochemistry.Stable isotopes of sulfur are an effective tool for tracking thiscatabolic process as microorganisms discriminate strongly againstheavy isotopes when cleaving the sulfur–oxygen bond. Alongwith its high preservation potential in environmental archives, awide variation in the sulfur isotope effects can provide insightsinto the physiology of sulfate reducing microorganisms across temporaland spatial barriers. A vast array of parameters, including phylogeny,temperature, respiration rate, and availability of sulfate, electrondonor, and other essential nutrients, has been explored as a possibledeterminant of the magnitude of isotope fractionation, and there isnow a broad consensus that the relative availability of sulfate andelectron donors primarily controls the magnitude of fractionation.As the ratio shifts toward sulfate, the sulfur isotope fractionationincreases. The results of conceptual models, centered on the reversibilityof each enzymatic step in the dissimilatory sulfate reduction pathway,are in qualitative agreement with the observations, although the underlyingintracellular mechanisms that translate the external stimuli intothe isotopic phenotype remain largely unexplored experimentally. Thisminireview offers a snapshot of our current understanding of the sulfurisotope effects during dissimilatory sulfate reduction as well astheir potential quantitative applications. It emphasizes the importanceof sulfate respiration as a model system for the isotopic investigationof other respiratory pathways that utilize oxyanions as terminal electronacceptors. Its abundanceand multiple valence states make it an essential player in microbialredox processes such as anaerobic photosynthesis and respiration.2 Sulfate is quantitatively the most abundant oxidantin seawater but behaves nearly conservatively under oxygenated conditionsas abiotic sulfate reduction is kinetically inhibited below 200 °C.3 In the deeper, anoxic layer of marine sediments,however, anaerobic respiration coupled to sulfate reduction accountsfor more than half of the organic matter remineralization.4 Dissimilatory sulfate reduction is thus a fundamentaldriver for the redox cycling of sulfur at physiological temperatures;otherwise the marine sulfur cycle would be dominated by precipitationand dissolution of sulfate minerals. A metabolic product of dissimilatorysulfate reduction, sulfide, reacts with iron and forms insoluble pyrite,some of which can be incorporated and retained in sedimentary rocksover geologic time. Such burial of sulfur reduced at the expense ofoxygenically produced organic carbon leaves dioxygen behind in theocean and atmosphere.5 Therefore, changesin the biogeochemical sulfur cycle, largely representing the flowof sulfur between the oxidized, soluble sulfate and the reduced, lesssoluble sulfide, have interacted extensively with the redox cycleof other elements, including the evolution of atmospheric oxygen.6Sulfur comprises about2% of the Earth’s mass, being thesixth most abundant element on our planet,32S (95.04%), 33S (0.75%), 34S (4.20%), and 36S (0.015%),7 and as a major regulator of the global sulfurcycle, dissimilatory sulfate reduction shapes the patterns of sulfurisotope distribution in the Earth’s surface environments. Insteadof absolute abundance, the sulfur isotope compositions are conventionallyreported with the delta notation in per mil variations relative tothe Vienna Canyon Diablo Troilite (VCDT): δXS = 1000× (XRsample/XRVCDT – 1), where XR is the XS/32S ratio . Unless specified otherwise, in thisminireview, sulfur isotope fractionation refers to the variationsin the abundance of the two most abundant isotopes, 32Sand 34S (34ε). Because the sulfur–oxygenbond containing heavier sulfur isotopes requires slightly more energyto break compared to the bond with 32S,9 dissimilatorysulfate reduction discriminates against heavy isotopes, producingsulfide depleted in 34S relative to the reactant sulfateby as much as 66‰.10 Compared tosulfate reduction, oxidative transformations of sulfur compounds involverelatively minor isotope fractionation from −6 to +12‰.11 Since first reported by Thode et al.,12 thus, sulfur isotope fractionation between sulfateand sulfide has been extensively used as a diagnostic marker for dissimilatorysulfate reduction in modern and ancient environments. Studies of thedeep biosphere hundreds of meters below the seafloor13 and the billions-year-old marine sedimentary rocks14 are such examples. Recently, the sulfur isotopesystematics on Mars and other extraterrestrial bodies have also emergedas a valuable tool for the search for potential biological signatures.15Sulfur has four stable isotopes, 16 Since respiratory sulfur isotope fractionation is a phenotypic responseto environmental factors via biochemical systems, an up to 70‰variation ensures that sulfur isotope signatures in nature can capturenot only the presence but also physiological information on sulfatereducing microorganisms. Importantly, the microbially fractionatedsulfur isotope ratios locked in minerals are more stable and retainedin sedimentary rocks over longer time scales than most constituentsof biochemical systems such as polynucleotides and proteins, whichmakes them attractive in a variety of applications to reconstructthe past microbial activities and environmental conditions. To linkthe magnitude of isotope fractionation to the environmental parameterssuch as temperature, pH and availability of sulfate, electron donorand other key nutrients, over 800 sulfur isotope measurements havebeen made in more than 50 species of sulfate reducing microorganisms(Supplementary Table 1 and references therein).In the past decade, individual enzymes and intracellular metabolitesinvolved in dissimilatory sulfate reduction have begun to be isotopicallyexamined in order to assess the biochemical mechanisms underlyingthe sulfur isotopic response to environmental stimuli.19 In this minireview, we summarize such progress that has been madeover the last half-century and highlight the remaining gaps in ourunderstanding of the sulfur isotope fractionation during sulfate respiration.In addition to its qualitative diagnosticvalue, dissimilatorysulfate reduction shows quantitatively a large range of sulfur isotopefractionation, ranging from −3 to +66‰.2+ or Na+ ions.20 Since sulfate is relatively inert under physiological conditions,it needs to be activated to APS prior to reduction at the expenseof ATP hydrolysis, and then APS is reduced to sulfite using two electronsfrom the membrane-bounded QmoABC complex.21 The final step of sulfate respiration begins with the two-electronreduction by DsrAB. It had been debated whether the complete reductionto sulfide involves thiosulfate (S2O32–) and trithionate (S3O62–) as intermediates,22 but Santos et al.23 demonstrated that sulfite reduction by DsrABproduces the trisulfide form of DsrC, which is further reduced tosulfide and the thiol form of DsrC by the membrane DsrMKJOP complex.Dissimilatory reduction of sulfate to sulfide involves four enzymes:sulfate permease (SulP), sulfate adenylyltransferase (Sat), adenosinephosphosulfate (APS) reductase (Apr), and dissimilatory sulfite reductase(Dsr) 1. First,24 the reversibility of the SulP, Sat, Apr, andDsr reactions and their kinetic isotope effects have served as thefoundation for theoretical models for dissimilatory sulfur isotopefractionation, although the details have been modified to accommodatenew findings.26These four enzymatic reactions primarily shapethe patterns ofsulfur isotope fractionation during the dissimilatory sulfate reduction.In a quasi-steady state, where the concentrations of reaction intermediatesremain approximately constant, the total isotope fractionation byany reversible, multistep enzymatic reaction can be expressed as afunction of the isotope effects of the enzymes involved and the relativerates of each enzymatic reaction 2A. Since25 For example, sulfate uptake has been assumed to produce a smallinverse sulfur isotope effect25 becauseHarrison and Thode16 reported that theisotope fractionation is inverted with 34SO42– reacting faster than 32SO42– at very low sulfate concentrations, where anincreasing number of symported cations limits the backward flow acrossthe membrane.27 There is a general consensusthat large sulfur isotope effects are associated with the breakingof sulfur–oxygen bonds, but it was in the past decade thatthe kinetic isotope effects of the two reductive enzymes in the dissimilatorysulfate reduction pathway were directly constrained. The Apr, isolatedfrom Desulfovibro vulgaris, fractionates the 34S/32S ratio by 20‰,19 which is 5‰ smaller than previously inferred.25 Although a sulfur isotope effect of 53‰has been predicted for the entire Dsr reaction to explain the observedsulfur isotope fractionations,22 Leavittet al.17 reported a fractionation of 15‰for the first two-electron reduction by DsrAB, isolated from D. vulgaris and Archaeoglobus fulgidus,suggesting that the following reactions involving cytosolic DsrC andmembrane-bound DsrMKJOP probably have a strong preference toward lightersulfur isotopes.In this scheme, the sulfur isotope effects assignedto each enzymaticreaction constrained the potential range of microbial sulfur isotopefractionation. Until recently, kinetic isotope effects at the differentsteps have been assigned principally considering the results of cultureexperiments and equilibrium calculations.R is the gas constant, T is the absolute temperature, and ΔG is the free energy change associated with the reaction. Since thevalue of ΔG strongly depends on the concentrationsof reactants and products, intracellular metabolite levels and theirdeterminants like specific respiration rates, substrate and wasteconcentrations, and activity and kinetic properties of the involvedenzymes should shape the patterns of sulfur isotope fractionation.26 Although a quantitative calibration of the modelparameters requires a better understanding of the relevant enzymesand the intracellular biochemical processes, current models predictthat either sulfate uptake or APS reduction acts as a metabolic bottleneckin the sulfate respiration pathway under physiological conditions.26Within the range defined by enzymatic sulfurisotope effects, itis the ratio of forward and backward reaction rates at each step ofthe dissimilatory sulfate reduction pathway that leads to variationsin sulfur isotope fractionation at the cellular level 2A and B,33.119 Marked differences in the responsesto temperature between enzyme- and cellular-level fractionations demonstratethat the reversibility, not the kinetics of individual enzyme, playsa key role in explaining large variations in dissimilatory sulfurisotope fractionation. Given the divergent results of previous culturestudies  as a couplingion, the free energy available from proton inflow is a primary drivingforce of sulfate uptake, and sulfate reducing microorganisms increasethe proton/sulfate stoichiometry of sulfate transport in responseto a decrease in the external sulfate concentration, accumulatingsulfate inside the cell.41 An increasingnumber of symported protons makes sulfate uptake more energeticallyfavored and less reversible, thereby reducing the isotopic fractionation.Because sulfate transport is the first step of dissimilatory sulfatereduction pathway, its reduced reversibility effectively nullifiesthe isotope effect of reductive enzymes in the downstream of the pathway.Relatively large isotope fractionation exceeding 20‰ has beenalso reported from natural habitats with micromolar concentrationsof sulfate.43 Thus, although sulfate availabilityis one of the crucial factors governing the magnitude of fractionation,sulfur isotope compositions may not provide a unique calibrator forambient sulfate concentrations.Both experimentally and theoretically, there is a strong consensusthat sulfate limitation tends to decrease the magnitude of fractionation,but the required threshold concentration of sulfate appears to varywith species and growth conditions. Habicht et al.3.346 The role of electron donors in sulfur isotope fractionation hasbeen extensively studied with pure cultures of dissimilatory sulfatereducers, demonstrating that the limitation by electron donors orthe presence of recalcitrant organic substrate increases the magnitudeof isotopic fractionation.51 Although there are some variations across species, sulfate reductioncoupled to the oxidation of molecular hydrogen or simple organic acidssuch as lactate produced a relatively small isotope effect, whilea larger sulfur isotope effect was obtained during the growth on carbohydratesor aromatic substrates  has beendescribed in several pure culture studies,51 which has been often used to predict the rate of sulfate reductionin the modern and ancient environments.51 The csSRRin pure culture studies covers a range of 0.002–860 fmol SO42–/cell/day, and with the exception of thetwo slowest rates reported from retentostat experiments,57 the maximum fractionation reached at the givencsSRR decreases rapidly as the rate increases, whereas the minimumvalue remains less than 10‰ .Our phylogenetic analysis of the expanded data set with more taxaand genes thus confirm the previous conclusion that the sulfur isotopefractionation by microorganisms is largely dependent on their physiologyrather than the phylogenetic positions.65 More specifically, it is the redox state of sulfate reducing microorganisms,but not the subtle structural variation between homologous enzymes,that has a greater influence on the changes in sulfur isotopic phenotypes.At a cellular level, Detmers et al. as rRNA 7. Regard indicus 7. Many o effects 7. Moreov438 This relationship has been extrapolatedto environmental levels and provided a qualitative measure of thesulfate reducing activity in marine sediments,67 the largest habitat for sulfate reducingmicroorganisms, where the rate of sulfate reduction usually dependson the amount of organic matters and their availability for biogenicdegradation.60 The use of sulfur isotopes asa quantitative indicator is however rather complex, in part becausethe reversibility of multiple steps cannot be uniquely resolved fromthe fractionation of the 34S/32S ratio , and whilethe fractionation of four sulfur isotopes exhibits a power law massdependency, a linear mixing of different sulfur pools along the sulfatereduction pathway and a slight difference of mass-dependent effectsin sulfur isotope fractionation processes make both 33S/32S and 36S/32S ratios measurably deviatefrom the single step low-temperature equilibrium trends.70 These variations do not exceed a few tenth of permil but carry uniqueinformation independent from that obtained in conventional δ34S analysis. The distribution of the metabolic fluxes throughthe dissimilatory sulfate pathway can be further illustrated by oxygenisotope measurements. Enzymatic reductions should lead to a shiftin the 18O/16O ratios of residual sulfate towardhigher values as is in the case of δ34S, while theoxygen isotope exchange between intracellular water and sulfite candecouple the isotope effects on sulfur and oxygen.72 Thus, a relationship between δ34S and δ18O values reflects the balance between the rate of sulfatereduction and the rates of isotope exchange and sulfite reoxidation.73 Using 17O-labeled water, the role of oxygen isotope exchangecan be assessed independently from the mass-dependent 18O/16O fractionation,74 andrecently, 34S–18O clumping in sulfatealso emerges as a promising tool to resolve the individual componentsof the microbial sulfate reduction pathway.76 Nevertheless, this theoretically promising approach requires isotopiccharacterization of the involved enzymes for quantitative analysis.52 To date, the triple sulfur isotope effect of DsrAB17 is the only available data on the multiple sulfur isotopefractionation imposed by the enzyme in the sulfate reduction pathway,and neither oxygen isotope effect nor rare isotope clumping has beeninvestigated. Further enzymatic studies are thus warranted to establisha firm basis for a quantitatively calibrated model that links themagnitude of fractionation to their biological controls.First, using isotope ratiosother than the traditional Desulfovibrio, submillimolar sulfate concentrations decrease the sulfur isotopefractionation by the marine sulfate reducing bacteria Desulfovibrioalaskensis down to a few permil, whereas the freshwater D. vulgaris fractionates sulfur isotopes by more than 20‰under the same condition.38 It is, however,worth noting that the reversibility of the overall pathway and therebythe sulfur isotope effect are the function of intracellular metabolitelevels and biochemical parameters such as membrane proton gradient,phosphorylation potential and intracellular redox state.77 Although the sulfate reductionpathway is highly conserved,62 metabolicpathways to translate various environmental stimuli into intracellularbiochemical signals are complex and more species-specific. Therefore,the magnitude of fractionation associated with sulfate respiration,if it is to be a quantitative indicator, needs to be calibrated againstthe intracellular redox and phosphorylation potentials, rather thandirectly against environmental parameters.Second,physiological differences between sulfate reducing microorganismsmay elicit differing sulfur isotopic responses to the same environmentalchanges. For example, within the genus 80Finally, given thatdissimilatory sulfate reduction is one of themost intensively studied metabolisms in the field of isotope geochemistry,the concepts discussed here and further progress in understandingthe sulfur isotope fractionation along the respiratory pathway canbe extended into other dissimilatory pathways that utilize oxyanionsas terminal electron acceptors.


Land–atmosphere coupling (LAC) plays a significant role in weather and climate and is related to droughts and heatwaves. We propose a simple and efficient LAC diagnosis method based on the analysis of water isotopes in atmospheric water vapour and precipitation. Using the method, we identify the primary LAC hotspot regions of the globe and reveal the seasonality of LAC strength. We find that LAC strength exhibits a relationship with latitude. Low latitudes present stronger LAC strength and contribute more significantly to the overall LAC area compared to boreal middle and high latitudes. It's important to note that LAC primarily manifests in the troposphere and is detected in the lower stratosphere of low latitudes, with limited influence observed in the stratosphere. However, the impact of LAC is noticeable in the upper stratosphere in boreal middle and high latitudes. Moreover, the seasonality of LAC strength is pronounced. On a global scale, the season with the strongest LAC is boreal autumn in the Northern Hemisphere but boreal summer in the Southern Hemisphere. Notably, this pattern does not exhibit a seesaw effect between the two hemispheres. Our isotope-based LAC diagnosis method captures the major LAC hotspots found in previous work and validates the seasonality of LAC within these hotspots. This substantiates the reliability and effectiveness of our isotope-based approach. Cioni and Hohenegger noted that precipitation is expected to increase with enhanced evaporation regardless of atmospheric state3. LAC can amplify heat extremes under declining soil moisture4. The soil state modulates LAC duration5. The wet-dry transition zone often has the strongest LAC9. The impact of LAC extends to the occurrence of extreme weather events, such as heavy rainfall, flooding, and droughts. It has been projected the frequency and intensity of concurrent soil drought and atmospheric aridity will greatly increase in the twenty-first century10. A comprehensive understanding of LAC is crucial for assessing and mitigating the risks associated with such events.The land–atmosphere coupling (LAC) investigates the interactions between the subsurface, land surface, and the atmosphere through the exchange of mass and energy, affecting several key mechanisms including boundary layer mixing, convection, cloudiness, or precipitation11. Previous studies have relied on physical and statistical models to explore LAC, with various diagnostic methods developed. For instance, the CTP-HI  framework can identify and classify LAC12. However, the framework relies on intensive and costly observation. The ability of physical models to capture the coupling signal relies on a reasonable representation of near-surface conditions14 and a relatively high resolution5, which limits the application of the physical model. The correlation between two characteristic variables related to the surface exchange process can be considered a useful LAC metric15. Thus, statistical models can be used to diagnose LAC. Soil moisture (SM) is one of the most important variables of the climate system as it constrains evapotranspiration, affecting the surface energy and water balance16, and is therefore widely employed for the identification of LAC17. The relationship between SM and surface temperature18, between SM and surface fluxes1, between SM and evapotranspiration19, and between SM and evaporative fractions (EF)20, and so on allows us to identify LAC. However, the inherent difficulty and relatively low accuracy of SM measurements have restricted the global application of these SM-based statistical models. Recently, multiple environmental factors were used to achieve a more accurate diagnosis of LAC20, which generally requires a large amount of data. As it stands, LAC diagnosis remains a significant challenge.However, despite its critical role in a changing world, measuring LAC directly in the real world has proven to be a formidable challenge21, water-related disasters, and multi-feedback mechanisms within the Earth's complex system. Nevertheless, the lack of high-quality, long-term, and globally distributed observations has impeded robust and realistic global LAC identification22. In response to this challenge, our study aims to introduce a novel, straightforward, precise, and efficient method for diagnosing LAC on a global scale. Importantly, our method distinguishes itself from existing approaches as it is the first isotope-based LAC diagnostic method. The results we present hold the potential to advance LAC diagnosis and deepen our understanding of this critical Earth system process.LAC plays a pivotal role in the evolution of weather and climate2H(D) or 18O. The equilibrium isotope fractionation factor α is defined by the equilibrium constant of this exchange reaction23. Specific values for the fractionation factors of oxygen and hydrogen isotopes are given as a function of the temperature24. Therefore, the water isotope composition in vapour (RV) is highly correlated with the composition in raindrops (RL).Isotope fractionation is defined as the phenomenon that the isotope ratio of an element in a certain compound changes by the transition of the compound from one physical state or chemical composition to another. The progressive rain out of the vapour masses is a main process in the global water cycle, concerning the water isotopes fractionation. Once the vapour has been formed, the rainout process proceeds in isotopic equilibrium, when the isotope fractionation between liquid water and vapour is written as:26. Both the oceanic and the terrestrial vapour belong to the external water cycle. Locally recycled vapour belongs to the internal water cycle. Besides, rainfall evaporation produces a minor part of atmospheric moisture27. The moisture originating from the external water cycle can be understood in terms of large-scale mixing among convective air parcels that have undergone various condensation and moistening processes23. Oceanic and terrestrial vapors in the external water cycle exhibit high dynamism, partly due to the short turnover time of atmospheric moisture. In addition, only a part of the moisture in an air column leads to precipitation over an extended period. For these reasons, the isotopic correlation between atmospheric vapour (RV) and precipitation (RL) is weak on a monthly scale, despite often being robust during storm events.The reservoir of atmospheric moisture in an air column is very dynamic, quickly responding to changes in external conditions. First, the mean turnover time  of water vapour in the global atmosphere is around 10 days concerning the net evaporation or precipitation fluxes. Second, the sources of water vapour are various, including oceanic evaporation vapour, terrestrial evapotranspiration vapour along the moisture trajectory, and locally recycled vapourRV and RL on a monthly scale. Soil moisture is usually recharged by precipitation. Signals of precipitation can be retained in soil moisture for days or months, a phenomenon known as soil moisture memory. Globally, the average soil moisture memory extends to about one month11. This implies that the isotopic signal of monthly precipitation can persist due to soil moisture memory. During the LAC, the locally cycled moisture that originated as evapotranspiration from soil moisture most recently from a specified area forms a part of precipitation falling over the same area11. The LAC enhances the local vapour cycling. However, because locally recycled vapor differs isotopically from the ambient water vapor in the external water cycle within an air column28, an increase in locally recycled moisture in an air column can strengthen the isotopic correlation between atmospheric vapor and precipitation on a monthly scale. Consequently, it is expected that strong LAC will promote a high correlation between monthly atmospheric vapor and monthly precipitation. For the same reason, LAC can be identified through the isotopic correlation between monthly precipitation and atmospheric vapor.However, LAC can enhance the correlation between Global monthly vertical profiles of HDO in the atmosphere were measured by the Tropospheric Emission Spectrometer (TES) aboard the Aura spacecraft. The TES data set is currently the most abundant water vapour isotopologue data set, which was provided at 2-degree latitude by 4-degree longitude spatial grids and at a subset of pressure levels . The Level 3 TES data are mostly sensitive to the 550 to 800 hPa layer, which is the area where most atmospheric water vapour is concentrated. Therefore, we employed the TES monthly HDO products of 825 hPa and 621 hPa to diagnose LAC.30. Thus, we downloaded monthly simulations (2006–2009) of global precipitation isotopes produced by isoGSM (nudged).SWING2  is a project to compare water-isotope-enabled general circulation model results across modeling groups. It was reported that simulations of HDO in precipitation produced by isoGSM  show lower standard deviation, RMSE (Root Mean Square Error), and higher correlation with GNIP  observations of water isotopes in precipitationr between TES monthly water vapour HDO at the pressure levels 825 hPa and 621 hPa and isoGSM monthly precipitation HDO were calculated at every grid point, respectively, and then the larger r (p < 0.05) was kept as the final result. The sample size for the correlation analysis was 48. Pearson’r > 0.5 (moderate correlation) was considered as the indicator of the occurrence of obvious LAC. Furthermore, strong LAC regions were recognized by r > 0.7 (strong correlation)31. Similarly, LAC was detected using Pearson’s r for every season. The sample size for each season was 12. The seasonality of LAC was recognized by the seasonal total areas of LAC regions and strong LAC regions. In addition, to test the effect of LAC on the troposphere and stratosphere, Pearson’s r between monthly water vapour HDO at all pressure levels and monthly precipitation HDO were calculated according to the above procedure. Data processing and analysis were executed using NCL (NCAR Command Language).The TES data were resampled to 1.875° × 1.889° (longitude × latitude) following isoGSM’s spatial resolution. To do a global diagnosis of LAC hotspots, Pearson’s We also downloaded data on precipitation, humidity, and air temperature  from the Climatic Research Unit and 0–40 cm soil moisture content data . Based on these data, we derived the 30-year average of monthly precipitation, humidity, air temperature and the 20-year average of monthly soil moisture content for recognized LAC hotspots.7 km2, accounts for 35% of the global terrestrial area. The area of strong LAC regions accounts for 44% of the LAC hotspot regions.Eleven LAC hotspot regions were recognized Fig. , includi–30°N) and characterized by plenty of energy input and available water. The seasonal variation of precipitation is significant, while the seasonal variation of air temperature is insignificant. The second group includes the rest six regions, which are located at boreal middle and high latitudes and characterized by moderate precipitation and low annual average air temperature . The weakest three LAC regions belong to the boreal middle-high-latitude group including LP, CSES, and EC. LP has the smallest area and the lowest proportion (15%). Therefore, low latitudes are considered the main zone of LAC.Many LAC hotspots worldwide are influenced by monsoons. The North America Monsoon affects GMR, the South America Monsoon controls ESA, the West Africa Monsoon dominates BCA, the South Africa Monsoon prevails in SA, and the Asian Monsoon influences IMSA, EC, and NEMP. Only four high-latitude LAC hotspots remain unaffected by monsoons.6 km2 and 23.9 × 106 km2, respectively, reaching the annual peaks  or soil moisture–evapotranspiration (SM-ET) coupling was demonstrated36. Generally, the LAC hot spots revealed by our method cover almost all regions with strong SM-P, SM-T, SM-ET, or CTP-HI couplings obtained by various methods41. A large range of soil moisture variation is a necessary condition for a strong LAC35. Furthermore, there are different correlations between LAC coupling strength and soil moisture anomalies over areas with a normally dry or wet climate7. In humidity-limit regions, strong ET will induce an obvious decline of SM, showing the SM-ET coupling. In energy-limit regions, strong ET will induce an obvious decline of adjacent air temperature, showing the SM-T coupling. Increased SM could also promote precipitation by an enlarged ET flux, showing the SM-P coupling in transition zones between wet and dry regions or transition periods between wet and dry seasons37. No matter what type the LAC is, the strong ET is the bond between land and atmosphere in the LAC processes. The evaporated SM brings the isotopic signal of water that usually was stored in the soil at monthly scales into atmospheric moisture and subsequently the precipitation. The SM-P, SM-ET, and SM-T couplings can therefore be captured based on the correlation between isotopic compositions of water vapour and precipitation.Our method successfully identified almost all primary LAC hotspots on a global scale. Our method identifies most of the soil moisture and precipitation (SM-P) coupling regions found by Koster et al.42. Afforestation and deforestation modified the LAC in Eastern European Plain and parts of Scandinavia and Eastern Europe by changing the surface flux partitioning43. Specially, increased LAC of SM-P was documented in areas of continuous Eurasian permafrost44. LAC in the other seasons is much weaker than in summer13, which is consistent with our result. The Indo-Gangetic Plain is one of the most densely populated areas on Earth, where summer is the prime LAC season45. Indochina region in spring and summer, and the Indian subcontinent in summer and fall were identified as LAC hot spots based on the soil moisture’s impact on temperature, evaporation, and EF35. According to our result, the Indochina region in summer and autumn, and the Indian subcontinent in autumn present significant LAC. The lower-middle reaches of the Yangtze River, North China, and Northeast China present strong LAC in summer and fall46. According to our result, significant LAC still occurs in the Huaihe River Catchment and the lower-middle reaches of the Yangtze River in winter. Temperature-related couplings are stronger in winter in humid areas8, which might be a possible explanation.Our method reveals similar LAC seasonality with previous studies in those hotspots. In central Europe, the LAC in Summer is strong, which further strengthens heatwaves47. In autumn when the monsoon nearly finishes, the areas of strong coupling primarily dominate the majority of the western part of northwestern Mexico where surface fluxes are suitably high but still sensitive to soil moisture48. Our result is similar to the previous results. The Great Plain of North America was recognized as a strong SM-P coupling region33. Recent observations show moderate to weak LAC in the Southern Great Plains in summer51. However, there is no LAC signal captured by our method, suggesting no LAC at least during our observation period. Semi-arid and arid continental climates dominate in the Great Plains. Droughts further threaten water availability in the region54. During our observation period, mega-droughts happened in the Southern United States, which could induce soil moisture depletion. Subsequently, the atmosphere is predisposed to limit precipitation and therefore not conducive to LAC.In North America, GMR includes southeastern Arizona–New Mexico in the U.S. and Northwest Mexico, the transitional zones between dry and wet climates, and U.S. Southeast, the eastern North American monsoon region. LAC in the U.S. Southeast is strong in summer, which is important for drought recovery55. Our result confirms that Cerrado, Caatinga, and Chaco are the LAC hotspots in boreal summer and autumn, the dry season. The spatial extent of the LAC region, based on our method, closely aligns with previous results in South America. The only exception is the eastern part of La Plata, which is not identified as an LAC region in our findings. Nevertheless, there are differences in the seasonality of LAC strength between Baker's results and ours, even though strong LAC is also observed in the boreal autumn (SON) in Baker's research. Cerrado, Caatinga, and Chaco are seasonally dry subtropical regions of woody savanna and serve as transition zones between wet and dry climates55. Moisture transport from lower latitudes sustains intense convective storms56. LAC usually tends to be significant over wet-dry transition zones57. The climate in these wet-dry transition zones is sensitive and subject to frequent changes. The seasonality of LAC strength can also vary from year to year due to climatic fluctuations. The difference in study periods partially accounts for the differences observed in the seasonality of LAC strength when comparing our results to previous findings. This underscores the importance of considering the impact of climate variability when interpreting these differences.In South America, recent work demonstrated that Amazon, Cerrado, Caatinga, and La Plata showed the strongest coupling in boreal winter, the wettest months57. For the whole Sahel , a strong LAC occurs in summer58. However, in our findings, the area covered by LAC regions is 1.7 times larger in autumn compared to summer, with an even more pronounced 2.7-fold increase in the area of strong LAC regions. Our isotope-based LAC diagnosis method identifies autumn as the season with the strongest LAC strength. On average, summer rainfall in BCA amounts to approximately 444 mm brought by the West African Monsoon, while autumn experiences an average of 257 mm  and other characteristic variables, such as precipitation (P), may be attributed to processes other than LAC during summer. Consequently, methods based on the correlations with SM tend to overestimate LAC strength in the summer months. Further studies are needed to develop deeper into this aspect.In the Western Sahel of Africa, LAC occurs in spring, just before the beginning of monsoon seasonmm Table . The sumer Table . However5. However, some studies noted that LAC is strongest in boreal winter58. Lorenz et al.41 also indicated that strong coupling is mainly constrained to the Southern Hemisphere in boreal winter, excluding rain forests. Although LAC also occurs in the Southern Hemisphere in boreal winter according to our results, boreal summer and autumn are still the main LAC periods. We believe that a see-saw pattern of LAC seasonality between the two hemispheres is unnecessary. In the Southern Hemisphere, oceans are dominated. Lands mainly distribute in low latitudes under tropical and subtropical climates without a clear four-season division. Moreover, conditions of water and energy in low latitudes are similar.For the southern African hotspot, SA, remarkable LAC occurs except for boreal spring, and reaches the most extent in summer, which is in agreement with the result of Müller et al.59. Similarly, from yearly to monthly, weekly, and daily scale, the correlations between SM and VPD are generally decreasing60. Instantaneous perturbation of precipitation would have a larger impact on LAC at a shorter time scale59. At the same time, high-resolution GCMs would improve the simulation of LAC due to the primary role of atmospheric conditions in LAC5. The differences in land use, anthropogenic activities, rooting depth, and soil type impose significant influences on LAC49, which could be reflected on a finer scale. The composition of temporal and spatial resolutions varies among studies, which is possibly responsible for the disagreement among LAC results. On the other hand, China has experienced substantial changes in vegetation cover, with increasing cropland in North China and forest in South China, which is considered to impose an influence on the seasonality of LAC61. In Southeast Asia, the LAC strength increased due to deforestation62. Cropland/grassland depletes soil moisture more readily than forests, thereby triggering a more rapid release of sensible fluxes42. Afforestation and deforestation modified the atmospheric humidity and stability by changing the surface flux partitioning43. Besides, in a warming world, an increase in boundary layer moisture in response to increased latent heat fluxes over areas of continuous Eurasian permafrost increases precipitation and low-level cloudiness44. Aerosols are also found to influence LAC over north-west India by modulating net radiation45. In the changing world, LAC is projected to increase across most of the globe63. A rapidly changing environment introduces interannual variation of LAC, which is responsible for the disagreement.There are still disagreements between our results and previous studies. The disagreements may be related to different spatiotemporal scales and environmental changes. The land surface to the atmosphere feedback is more significant as time scales increase from daily to monthly, indicating more significant coupling at longer time scales59, which suggests there is an upper limit in the atmospheric segment of LAC. The effects of changing soil conditions on atmospheric moisture can be evident at 500 hPa44, which corresponds to the middle troposphere. Previous results were limited by observations. The results might have been underestimated. We derived LAC area at different pressure levels for every hotspot domain  in the upper stratosphere of the mid-high-latitude region due to higher temperature (maximum 3–17 °C) compared to the lower stratosphere. However, we must point out that the detected LAC-like signal in the upper stratosphere of mid-high-latitude hot spots does not validate the LAC in the stratosphere. Adequate water vapor transport from the troposphere to the stratosphere, diffusion of water vapor within the stratosphere, and a prolonged residence time of water vapor at these altitudes are all likely contributing factors to the emergence of these LAC-like signals. Stratospheric water remains an open issue. More observations and modeling are needed to resolve this issue.ET-LCL (lifting condensation level) coupling is a key process that determines the soil moisture-precipitation couplingain Fig. . ResultsThe newly proposed isotope-based LAC diagnosis method relies on water isotope data in both precipitation and atmospheric water vapor. A long-term series of the isotope data is essential for a precise diagnosis because a sample size larger than 30 is optimal for the correlation analyses used in the method. However, for the large-scale study, TES and SWING2 serve as indispensable data sources. TES provides data from 2004 to 2018. At the same time, SWING2 offers data from 1979 to 2009. To maintain data continuity and integrity, we opted to utilize data from 2006 to 2009 for both sources. This results in a sample size of 12 for seasonal LAC diagnosis, introducing a source of uncertainty in the seasonal LAC outcome. Nonetheless, our study produces comparable and reasonable results, highlighting the potential of an isotope-based LAC diagnosis method despite data limitations. The introduction of our innovative LAC diagnostic method into the scientific community is poised to spark greater interest and stimulate further research efforts.7 km2, accounts for 35% of the global terrestrial area. The area of the strong LAC regions accounts for 44% of the LAC hotspot regions. There are no LAC in tropical rainforests, aridity zones, terrestrial glaciers and ice sheets. Low latitudes present stronger LAC strength and contribute more LAC area than the boreal middle and high latitudes. LAC hotspot regions in low latitudes are influenced by monsoons. LAC can be evident within the whole troposphere, while LAC is also detected in the lower stratosphere of low latitudes. In addition, the impact of LAC can even be detected in the upper stratosphere of mid-high-latitude. The seasonality of LAC strength is significant in all LAC regions. Globally, the boreal autumn and summer are the strong LAC period. The strongest LAC generally happens in autumn in the North Hemisphere, while in the boreal summer of the South Hemisphere. Significant ET flux is the key process in LAC, which transports the isotopic signal of soil moisture into atmospheric moisture and subsequently precipitation. In essence, moderate precipitation and energy input are requisite for strong LAC. At low latitudes, the four seasons are not clear with tropical and subtropical climates, and water and energy conditions are similar. Thus, there is no seesaw pattern of LAC strength between the two hemispheres. Compared to previous results, disagreements in hot spots and seasonality of LAC can be explained as the results of different spatiotemporal scales and environmental changes among studies.In this paper, we proposed a novel LAC diagnosis method based on water isotopes in vapour and precipitation and verified the method at a global scale for the period from 2006 to 2009. Our method successfully identifies LAC hotspot regions and the seasonality of LAC strength. The total area of the LAC hotspot regions, 5.23 × 10Our LAC diagnosis method is a simple and efficient tool. Our study not only serves to further illustrate LAC but also serves as a starting point for the development of a universal isotopic tool for LAC diagnoses. In the future, our method could be applied to various spatiotemporal scales to verify the existence of an optimal scale. Besides, the strong LAC in high latitudes is highlighted in our result. However, relevant studies are currently rare. Given the sensitive responses to warming and significant feedback from LAC, attention is needed in future works.Supplementary Information.