The Population Council tackles intersecting inequalities that undermine rights and access to contraception, HIV and STI prevention, maternal and newborn health, safe abortion, prevention and treatment of infertility, and sexuality education, among other sexual and reproductive health needs. Our research and partnerships ensure high quality, evidence-based, voluntary, and rights-based comprehensive care for sexual and reproductive health.
Visit the Council's website to learn more.
Submissions from 2022
Did COVID-19 impact contraceptive uptake? Evidence from Senegal, Kamil Fuseini, Leah Jarvis, Augustine Ankomah, Fatou Mbow, and Michelle J. Hindin
Differences in HIV, STI and other risk factors among younger and older male sex workers who have sex with men in Nairobi, Kenya, Nicholas Muraguri, Jerry Okoth Okal, Marleen Temmerman, Helgar Musyoki, and Peter Gichangi
Discovery of novel HIV protease inhibitors using modern computational techniques, Sunday Okafor and Pavimol Angsantikul
Discovery of novel HIV protease inhibitors using modern computational techniques, Sunday Okafor, Pavimol Angsantikul, and Hashim Ahmed
DREAMS Implementation Science: Data from surveys with men in Eswatini (Round 2), Ann Gottert, Julie Pulerwitz, Patrick Shabangu, Bhekumusa Lukhele, Louis Apicella, and Sanyukta Mathur
DREAMS Implementation Science: Data from surveys with men in South Africa (Round 1 & 2), Ann Gottert, Julie Pulerwitz, Cherie Cawood, David Khanyile, and Sanyukta Mathur
Drug repurposing for HIV-1 protease inhibitors: High throughput virtual screening, rigid molecular docking and molecular dynamics studies, Sunday Okafor, Pavimol Angsantikul, and Hashim Ahmed
Effect of adolescent female fertility and healthcare spending on maternal and neonatal mortality in low resource setting of South Asia, Shongkour Roy and Tanjina Khatun
Effects of men’s lifetime adverse events experience on violence, HIV risk, and wellbeing: Insights from three countries, Julie Pulerwitz, Tracy McClair, Ann Gottert, Patrick Shabangu, Cherie Cawood, Effie Chipeta, and Sanyukta Mathur
Essential oils block cellular entry of SARS-CoV-2 delta variant, Luiz Torres Neto, Maria Lúcia Guerra Monteiro, José Fernández-Romero, Natalia Teleshova, James Sailer, and Carlos Adam Conte Junior
Estradiol inhibits HIV-1BaL infection and induces CFL1 expression in peripheral blood mononuclear cells and endocervical mucosa, Neeharika Verma, Sampurna Mukhopadhyay, Patrick Barnable, Marlena Gehret Plagianos, and Natalia Teleshova
Evaluating the impact of three progestin-based hormonal contraceptive methods on immunologic changes in the female genital tract and systemically (CHIME Study): A prospective cohort study protocol, Lisa Haddad, Gina Bailey Herring, C. Christina Mehta, Tyree Staple, Marisa R. Young, Sakthivel Govindaraj, Vijayakumar Velu, and Alicia K. Smith
Evaluation of a gender synchronized family planning intervention for married couples in rural India: The CHARM2 cluster randomized control trial, Anita Raj, Mohan Ghule, Nicole Johns, Madhusudana Battala, Shahina Begum, Anvita Dixit, Florin Vaida, Niranjan Saggurti, Jay G. Silverman, and Sarah Averbach
Evaluation of RISE II integrated social and behavior change activities in Niger: Baseline report, Leanne Dougherty, Lynn Abu Turk, Nrupa Jani, and Chaibou Dadi
Examining roles, support, and experiences of community health workers during the COVID-19 pandemic in Bangladesh: A mixed methods study, Shongkour Roy, Sarah Kennedy, Sharif M.I. Hossain, Charlotte E. Warren, and Pooja Sripad
Experience of care of hospitalized newborns and young children and their parents: A scoping review, Charity Ndwiga, Charlotte E. Warren, Chantalle Okondo, Timothy Abuya, and Pooja Sripad
Exploring awareness of obstetric fistula in eastern and northern Nigeria: Perceived causes, symptoms, and availability of treatment services, Emmanuel Nwala, Charles Nwaigwe, Pooja Sripad, Charlotte E. Warren, Salisu Mohammed Ishaku, and Solomon Kongyamba
Exposed and sequestered antigens in testes and their protection by regulatory T cell-dependent systemic tolerance, Jessica Harakal, Hui Qiao, Karen Wheeler, Claudia Rival, Alberta G.A. Paul, Daniel M. Hardy, C. Yan Cheng, Erwin Goldberg, and Kenneth S.K. Tung
Expressions of power in health care providers’ experiences and behavior, Breakthrough RESEARCH
Extramarital fertility in low- and middle-income countries, John Bongaarts and John B. Casterline
Facteurs associés aux bessoins non satisfaits en planification familiale au Sénégal : analyse approfondie des Enquêtes Démographiques et de Santé Continues 2018 et 2019, Thierno Souleymane Ball Anne, Fatou Mbow, Papa Ibrahima Ndour, Marème Mady Ndiaye, Amadou Youm, and El Hadji Yaya Ly
Family planning in factory settings: A mixed-method evaluation of a peer-led intervention, Nahla G. Abdel-Tawab, Reham Abou El-Fadl, Aparna Jain, and Noha El-Khorazaty
Family planning services during the first wave of COVID-19 in four West African countries: Lessons from a study, Aguima Frank Tankoano, Hassane Atamo, and Dela Nai
Feasibility of e-commerce pharmacy provision and acceptability of levonorgestrel 1.5 mg for pericoital use in urban and peri-urban settings in Kenya: A prospective cohort study, George Odwe, Brent McCann, Wilson Liambila, Jessica Vandermark, Daniel Mwanga, Edna Anab, Moses Wanami, and Saumya RamaRao
Fertility Transition in the Developing World, John Bongaarts and Dennis Hodgson
Focus group discussions on Syrian refugees' access to reproductive health services in Lebanon, Rima Mourtada and Andrea J. Melnikas
Freeze-drying for the preservation of immunoengineering products, Nagavendra Kommineni, Arun Butreddy, Vaskuri G.S. Sainaga Jyothi, and Pavimol Angsantikul
Global assessments of sexual and reproductive health needs of rural-urban migrants in an urbanizing world, Leiwen Jiang and Timothy Thomas
Great Expectations: Expanding the Possibilities for Research in Refugee Settings in the East and Horn of Africa, Chi-Chi Undie
Health worker perceptions of stigma towards Zambian adolescent girls and young women: A qualitative study, Caroline Meek, Drosin Mulenga, Patrick Edwards, Sophie Inambwae, Nachela Chelwa, Michael Mbizvo, Sarah Roberts, Sujha Subramanian, and Laura Nyblade
Healthy women, healthy families: Summary of findings from baseline assessment, Sharif M.I. Hossain, Shongkour Roy, Sigma Ainul, Abdullah Al Mahmud Shohag, A.T.M. Rezaul Karim, and Ubaidur Rob
Hearing from men living with HIV: Experiences with HIV testing, treatment, and viral load suppression in four high-prevalence countries in sub-Saharan Africa, John Mark Wiginton, Sanyukta Mathur, Ann Gottert, Nanlesta Pilgrim, and Julie Pulerwitz
How can behavioral determinant data inform family planning SBC programs and policies?, Leanne Dougherty and Phil Anglewicz
How do changes in motivation to prevent pregnancy influence contraceptive continuation? Results from a longitudinal study with women who receive family planning services from community pharmacists and patent and proprietary medicine vendors in Nigeria, Sara Chace Dwyer, Sikiru Baruwa, Emeka Okafor, Babajide Oluseyi Daini, Osimhen Ubuane, and Aparna Jain
How do fertility intentions lead to contraceptive continuation among a cohort of family planning users who received services from the private sector in Nigeria, Sara Chace Dwyer, Aparna Jain, Sikiru Baruwa, Emeka Okafor, Babajide Oluseyi Daini, and Osimhen Ubuane
How to leverage social listening to inform social and behavior change programs, Martha Silva and Jonathan Walker
How to use a theory of change to monitor and evaluate social and behavior change programs, Breakthrough RESEARCH
Husbands’ concerns and experiences with the progesterone vaginal ring in three sub-Saharan African countries: A mixed methods study, Francis Obare Onyango, Fatou Mbow, Saumya RamaRao, and Avishek Hazra
Identification des changements les plus significatifs sur la communication intergénérationnelle et la santé des jeunes en matière de planification familiale et de santé de reproduction : évaluation qualitative de la campagne médiatique « Merci Mon Héros » au Niger et en Côte d’Ivoire, Martha Silva, Sethson Kassegne, Robert-Hugues Yaovi Nagbe, Rebecca Ezouatchi, Lorimpo Babogou, and Farida Moussa
If we ask, will they tell? (and then, what?): Screening for sexual violence against children in Kenya, Chi-Chi Undie and Margaret Mak'anyengo
Impact of community and provider-driven social accountability interventions on contraceptive uptake in Ghana and Tanzania, Petrus S. Steyn, Joanna Paula Cordero, Dela Nai, Donat Shamba, Kamil Fuseini, Sigilbert Mrema, Ndema Habib, My Huong Nguyen, and James Kiarie
Impact of COVID-19 on adolescent HIV prevention and treatment research in the AHISA Network, Elizabeth D. Lowenthal, Stephanie M. DeLong, Brian Zanoni, Irene Njuguna, Kristin Beima-Sofie, Dorothy Dow, Aisa Shayo, Alana Schreibman, Charisse V. Ahmed, Jennifer Chapman, Lydia Chen, Shreya Mehta, and Michael Mbizvo
Impact of COVID-19 on the use of emergency contraceptives in Ghana: An interrupted time series analysis, Kamil Fuseini, Leah Jarvis, Michelle J. Hindin, Kofi Issah, and Augustine Ankomah
Implementation and evaluation of a large-scale postpartum family planning program in Rwanda: Study protocol for a clinic-randomized controlled trial, Kristin M. Wall, Rosine Ingabire, Amelia Mazzei, Claudine Umuhoza, Rachel Parker, Amanda Tichacek, Azhar Nizam, Jessica M. Sales, Lisa Haddad, Phaedra Corso, Susan Allen, Julien Nyombayire, and Etienne Karita
Incidence and characteristics of stillbirths before and during the Coronavirus 2019 pandemic, Kavita Vani, Fatima Estrada Trejo, Marlena Gehret Plagianos, Morit Segui, Thammatat Vorawandthanachai, Lisa Nathan, and Francine Hughes
Informational materials: Dual prevention pill, Population Council
Informing social media campaigns through social listening and monitoring summary, Digital Health Compendium
Inroads for HIV prevention among men: Findings from mixed methods research in the context of the DREAMS partnership in Southern Africa, Ann Gottert, Julie Pulerwitz, Craig Heck, Patrick Shabangu, Bhekumusa Lukhele, Cherie Cawood, David Khanyile, Louis Apicella, Jerry Okoth Okal, and Sanyukta Mathur
Integrated health care delivery for adolescents living with and at risk of HIV infection: A review of models and actions for implementation, Sujha Subramanian, Eleanor Namusoke-Magongo, Patrick Edwards, Millicent Atujuna, Teddy Chimulwa, Dorothy Dow, Emilia Jalil, Nguavese Torbunde, Kawango Agot, Ivan Arinaitwe, Jenny Beizer, Nachela Chelwa, Scovia Nalugo Mbalinda, Sam Miti, and Florence Mwangwa
Intersections of financial agency, gender dynamics, and HIV risk: A qualitative study with adolescent girls and young women in Zambia, Laura Gauer Bermudez, Drosin Mulenga, Maurice Musheke, and Sanyukta Mathur
Interventions to improve the reproductive health of undocumented female migrants and refugees in protracted situations: A systematic review, Silvana Larrea-Schiavon, Lucía Vázquez Quesada, Lindsay R. Bartlett, Nayeli Lam-Cervantes, Pooja Sripad, Isabel Vieitez Martínez, and Liliana Coutiño-Escamilla
Is living in a region with high groundwater arsenic contamination associated with adverse reproductive health outcomes? An analysis using nationally representative data from India, Jessie Pinchoff, Brent Monseur, Sapna Desai, Katelyn Koons, Ruben Alvero, and Michelle J. Hindin
“Just Another GBV Training Session”: Reflections on Psychosocial Response in the Context of Research, Chi-Chi Undie
Key learnings from an outcome and embedded process evaluation of a direct to beneficiary mobile health intervention among marginalised women in rural Bihar, India, Laili Irani, Supriya Verma, Ruchika Mathur, Raj Kumar Verma, Diwakar Mohan, Diva Dhar, Aaditeshwar Seth, Indrajit Chaudhuri, Mahua Roy Chaudhury, Apolo Purthy, Ankit Nanda, Shivani Singh, Akshay Gupta, and Amnesty Elizabeth Lefevre
L’engagement des médias de l’Afrique de l’Ouest Francophone dans l’atteinte des objectifs du Partenariat de Ouagadougou : Le concours d’excellence en production médiatique des journalistes et blogueurs, Thierno Souleymane Ball Anne, Fatou Mbow, and Thiaba Sembène
Longitudinal examination of young married women's fertility and family planning intentions and how they relate to subsequent family planning use in Bihar and Uttar Pradesh India, Ilene Speizer, A.J. Francis Zavier, Lisa M. Calhoun, Priya Nanda, Niranjan Saggurti, and Gwyn Hainsworth
Manifestations, responses, and consequences of mistreatment of sick newborns and young infants and their parents in health facilities in Kenya, Timothy Abuya, Charlotte E. Warren, Charity Ndwiga, Chantalle Okondo, Emma Sacks, and Pooja Sripad
MARK2 and MARK4 regulate Sertoli cell BTB dynamics through microtubule and actin cytoskeletons, Elizabeth I. Tang and C. Yan Cheng
Matching intent with intensity: Implementation research on the intensity of health and nutrition programs with women's self-help groups in India, Avishek Hazra, Aikantika Das, Jaleel Ahmad, Shivani Singh, Indrajit Chaudhuri, Apollonius Purty, Audrey Prost, and Sapna Desai
Measuring potential interest in a postpartum contraceptive vaginal ring among breastfeeding women in India, Lorna Begg, James Sailer, Avishek Hazra, Malabika Roy, Ruth Merkatz, Lisa Haddad, Rebecca Brodsky, and John Bongaarts
Multisectoral, combination HIV prevention for adolescent girls and young women: A qualitative study of the DREAMS implementation trajectory in Zambia, Joseph G. Rosen, Maurice Musheke, Drosin Mulenga, Edith S. Namukonda, Nrupa Jani, Michael Mbizvo, Julie Pulerwitz, and Sanyukta Mathur
Multisite, mixed methods study to validate 10 maternal health system and policy indicators in Argentina, Ghana and India: A research protocol, R. Rima Jolivet, Jewel Gausman, Richard M. Adanu, Delia Bandoh, Maria Belizan, Mabel Berrueta, Suchandrima Chakraborty, Ernest Kenu, Nizamuddin Khan, Magdalene Odikro, Veronica Pingray, Sowmya Ramesh, Niranjan Saggurti, Paula Vázquez, and Ana Langer
Necesidades y atención en salud sexual y reproductiva de mujeres migrantes en México: Un estudio desde Ciudad Juárez—Volumen 3, Jesús Peña, Lucía Vázquez Quesada, and Isabel Vieitez Martínez
Nestorone nanosuspension-loaded dissolving microneedles array patch: A promising novel approach for “on-demand” hormonal female-controlled peritcoital contraception, Ebru Altuntaş, Ismaiel A. Tekko, Lalitkumar K. Vora, Narender Kumar, Rebecca Brodsky, Olivier Chevallier, Emma McAlister, Qonita Kurnia Anjani, Helen O. McCarthy, and Ryan F. Donnelly
New client-centered discontinuation measures using the Demographic and Health Survey calendar data, Aparna Jain and Elizabeth Tobey
Nigerian stakeholders' perceptions of a pilot tier accreditation system for Patent and Proprietary Medicine Vendors to expand access to family planning services, Funmilola OlaOlorun, Aparna Jain, Emily Olalere, Ene Daniel-Ebune, Kayode Afolabi, Emeka Okafor, Sara Chace Dwyer, Osimhen Ubuane, Toyin O. Akomolafe, and Sikiru Baruwa
Operationalizing the distribution of oral HIV self-testing kits to men who have sex with men (MSM) in a highly homophobic environment: The Nigerian experience, Adekemi Sekoni, Waimar Tun, Osasuyi Dirisu, Temitope Ladi-Akinyemi, Elizabeth Shoyemi, Sylvia Adebajo, Folasade Ogunsola, and Lung Vu
Oral PrEP consultations among adolescent girls and young women in Kisumu County, Kenya: Insights from the DREAMS program, Craig Heck, Sanyukta Mathur, Habel Alwang’a, Oluoch-Madiang’ Daniel, Rael Obanda, Mophine Owiti, and Jerry Okal
Patent: System for providing birth control, Bruce Variano
People's care seeking journey for a chronic illness in rural India: Implications for policy and practice, Sumit Kane, Madhura Joshi, Sapna Desai, Ajay Mahal, and Barbara McPake
Perceptions and predictors of respectful maternity care in Malawi: A quantitative cross-sectional analysis, Carolyn Smith Hughes, Martha Kamanga, Alisa Jenny, Brady Zieman, Charlotte E. Warren, Dilys Walker, and Abigail Kazembe
Persistence of female genital mutilation/cutting in two Kenyan communities: What can we learn from change that falls short of abandonment?, Dennis Matanda, Caroline W. Kabiru, Chantalle Okondo, and Bettina Shell-Duncan
Planning for injecting drug use as a means to prevent risky injection behavior, Mary Philip Sebastian, Avina Sarna, Lopamudra Saraswati, Vartika Sharma, Ira Madan, Waimar Tun, and Ibou Thior
Prevalence and factors associated with anogenital warts among sexual and gender minorities attending a trusted community health center in Lagos, Nigeria, Sylvia Adebajo, Rebecca G. Nowak, Ruxton Adebiyi, Elizabeth Shoyemi, Charles Ekeh, Habib O. Ramadhani, Charlotte A. Gaydos, Julie Ake, Stefan Baral, Manhattan E. Charurat, Trevor A. Crowell, and TRUST/RV368 Study Group
Progress in male contraception: A brief summary of the Third International Congress on Male Contraception, May 2022, Christina Wang, Diana Blithe, Stephanie Page, David Serfaty, and Régine Sitruk-Ware
Promoting healthy couples’ communication to improve reproductive health outcomes, Robert Ainslie, Angie Brasington, G. Arzum Ciloglu, Leanne Dougherty, Busara Drezgic, Jill Gay, Lucia Gumbo, and Geoffrey Rugaita
Psychosocial influences on pregnancy and childbirth behaviours in north-western Nigeria: A cross-sectional analysis, Emily White Johansson, Udochisom Anaba, Dele Abegunde, Mathew Okoh, Shittu Abdu-Aguye, Paul C. Hewett, and Paul Hutchinson
Qualitative evaluation of Breakthrough ACTION/Nigeria’s community capacity strengthening approach to sustaining integrated social and behavior change programming: Phase I, Martha Silva, Nrupa Jani, Adetunji Adetayo, and Mayokun Adediran
Qualitative examination of the role and influence of mothers-in-law on young married couples' family planning in rural Maharashtra, India, Anvita Dixit, Mohan Ghule, Namratha Rao, Madhusudana Battala, Shahina Begum, Nicole E. Johns, Sarah Averbach, and Anita Raj
Quality of anthropometric data in India's National Family Health Survey: Disentangling interviewer and area effect using a cross-classified multilevel model, Laxmi Kant Dwivedi, Kajori Banerjee, Radhika Sharma, Rakesh Mishra, Sowmya Ramesh, Damodar Sahu, Sanjay Kumar Mohanty, and K.S. James
Quality of care in abortion in the era of technological and medical advancements and self-care, Ankita Shukla, Lucía Vázquez Quesada, Isabel Vieitez Martínez, Rajib Acharya, and Saumya RamaRao
Quality of services offered to women with female genital mutilation across health facilities in a Kenyan county, Samuel Kimani, Chantalle Okondo, Jacinta Muteshi-Strachan, and Jaldesa Guyo
Quels sont les principaux obstacles et facteurs de facilitation associés à la communication intergénérationnelle sur la SSR au Niger et en Côte d’Ivoire?, Breakthrough RESEARCH
Recap of the Sixth International Symposium on Intrauterine Devices and Systems for Women's Health, Rachel Ferat, Lisa Haddad, Carolyn Westhoff, and David Hubacher
Removing the societal and legal impediments to the HIV response: An evidence-based framework for 2025 and beyond, Anne L. Stangl, Triantafyllos Pliakas, Jose Antonio Izazola-licea, George Ayala, Tara S. Beattie, Laura Ferguson, Luisa Orza, Sanyukta Mathur, Julie Pulerwitz, Alexandrina Iovita, and Victoria Bendaud
Research and implementation interactions in a social accountability study: Utilizing guidance for conducting process evaluations of complex interventions, Joanna Paula Cordero, Vernon Mochache, Victoria Boydell, Mary Awelana Addah, Heather McMullen, Alice Monyo, Sigilbert Mrema, Dela Nai, Donat Shamba, and Petrus S. Steyn
Restrictions on contraceptive services for unmarried youth: A qualitative study of providers’ beliefs and attitudes in India, Ankita Shukla, Abhishek Kumar, Arupendra Mozumdar, Rajib Acharya, Kumudha Aruldas, and Niranjan Saggurti
Role of laminin and collagen chains in human spermatogenesis—Insights from studies in rodents and scRNA-Seq transcriptome profiling, Xiaolong Wu, Sheng Gao, Lingling Wang, Tiao Bu, Siwen Wu, Liwei Zhou, Jie Shi, Di Wu, Fei Sun, and C. Yan Cheng
S’attaquer aux tabous de la communication pour le changement social et de comportement à Niamey et Abidjan: Évaluation de la campagne médiatique Merci Mon Héros, Breakthrough RESEARCH
SBC Cost Data Repository, Breakthrough RESEARCH
SBC Costing Tool, Breakthrough RESEARCH
Setting up a research agenda for financing sexual and reproductive health services toward achieving universal health coverage in South Asia, Avishek Hazra, Arupendra Mozumdar, Iram Kamran, Ashish Bajracharya, and Saumya RamaRao
Sexual and reproductive health education and its association with ever use of contraception: A cross-sectional study among women in urban slums, Accra, Abdul-Aziz Seidu, Edward Kwabena Ameyaw, Bright Opoku Ahinkorah, Leonard Baatiema, Samuel Dery, Augustine Ankomah, and John Kuumuori Ganle
Sexual debut and risk behaviors among orphaned and vulnerable children in Zambia: Which protective deficits shape HIV risk?, Joseph G. Rosen, Nkomba Kayeyi, Mwelwa Chibuye, Lyson Phiri, Edith S. Namukonda, and Michael Mbizvo
Sexually transmitted infections in pregnant people with human immunodeficiency virus: Temporal trends, demographic correlates, and association with preterm birth, Marisa R. Young, Carly Broadwell, Deborah Kacanek, Ellen G. Chadwick, Jennifer Jao, Anna Barbara Moscicki, Kathleen Powis, Katherine Tassiopoulos, Lynn M. Yee, and Lisa Haddad
ShangRing versus Mogen clamp for early infant male circumcision in eastern sub-Saharan Africa: A multicentre, non-inferiority, adaptive, randomised controlled trial, Spyridon P. Basourakos, Quincy G. Nang, Karla V. Ballman, Omar Al Hussein Al Awamlh, Nahid Punjani, Kaylee Ho, Mark Barone, Quentin Awori, Daniel Ouma, Jairus Oketch, Alice E. Christensen, Augustino Hellar, Maende Makokha, Alphonce Isangu, Robert Salim, Jackson Lija, Ronald H. Gray, Stephen Kiboneka, Aggrey Anok, Godfrey Kigozi, Regina Nakabuye, Charles Ddamulira, Andrew Mulooki, Silas Odiya, Rose Nazziwa, Marc Goldstein, Philip S. Li, and Richard K. Lee
Small molecules targeting SARS-CoV-2 spike glycoprotein receptor-binding domain, Yoel Rodriguez, Scarlet Martínez Cardoze, Onyinyechi W. Obineche, Claudia Melo, Ashanna Persaud, and José Fernández-Romero
SNAC for enhanced oral bioavailability: An updated review, Nagavendra Kommineni, Vaskuri G.S. Sainaga Jyothi, Arun Butreddy, Saka Raju, Tovi Shapira, Wahid Khan, Pavimol Angsantikul, and Abraham J. Domb
Social normative origins of the taboo gap and implications for adolescent risk for HIV infection in Zambia, Sophia N. Nesamoney, Iván Mejía-Guevara, Beniamino Cislaghi, Ann M. Weber, Michael Mbizvo, and Gary L. Darmstadt