Stanford University
Showing 741-760 of 2,035 Results
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Siegfried Hecker
Professor (Research) of Management Science and Engineering and Senior Fellow at the Freeman Spogli Institute for International Studies, Emeritus
Current Research and Scholarly Interestsplutonium science; nuclear weapons stockpile stewardship; cooperative threat reduction
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Alex Hedgpeth
Postdoctoral Scholar, Earth System Science
BioAlexandra Hedgpeth is a biogeochemist whose research explores how soil carbon cycling in peatlands responds to environmental change. Her work focuses on understanding the mechanisms that regulate carbon storage and greenhouse gas production in both tropical and boreal wetlands, with a particular emphasis on the vulnerability of deep, ancient carbon to modern surface inputs and hydrologic shifts.
Through her Ph.D. research at the University of California, Los Angeles, Alex has developed and applied novel isotopic and geochemical approaches—including implementing radiocarbon dating, stable isotope analyses, and high-resolution molecular characterization—to trace the sources and fates of carbon in peat soils. Her fieldwork spans a range of ecosystems, from ombrotrophic bogs in the Arctic to saturated tropical peat domes in Central America. This comparative framework allows her to identify unifying controls on carbon preservation and loss across climate zones.
Alex's research integrates field measurements, laboratory experiments, and synthesis of global datasets. She is a key contributor to multi-institutional efforts to model peatland carbon cycling under climate change scenarios, including DOE- and NSF-supported initiatives. Her work helps clarify the role of peatlands as both long-term carbon sinks and potential sources of atmospheric CO₂ and CH₄ under future disturbance.
In addition to her scientific contributions, Alex is committed to collaborative, interdisciplinary research and has worked closely with partners at national laboratories, the Smithsonian Tropical Research Institute, and international data synthesis networks. She is especially interested in questions with high uncertainty and high relevance to climate feedbacks—such as thresholds in biogeochemical function and the persistence of deep soil carbon under hydrologic change. -
Britt Hedman
Professor of Photon Science
BioBritt Hedman’s research program is focused on the development and applications of x-ray absorption and emission spectroscopies using synchrotron radiation, with a scientific emphasis primarily on study of the electronic and structural aspects of metal ion active sites in bioinorganic and biological systems. A common theme is to investigate how structure at molecular and macromolecular levels relates to function.
A major long-term focus has been the active site of the enzyme nitrogenase, and the various nitrogenase metal clusters, including elucidating the electronic and geometric structure of those that are formed and changed along their biosynthetic pathways. Other systems of systematic studies include iron-sulfur cluster containing enzymes, blue and multi-copper proteins, heme-copper oxidases, and iron-containing oxidases. Methods developments include x-ray absorption spectroscopy (edge and extended fine structure - or EXAFS), including the application of multiple-scattering analysis in EXAFS studies of metal clusters relevant to bioinorganic systems, the development of methodology for polarized single crystal x-ray absorption spectroscopy, and methodology and instrumentation development for soft- through hard-energy XAS.
Britt Hedman received her B.S and B.A. in Chemistry, M.Sc. in Inorganic Chemistry, and Ph.D. in Chemistry from the University of Umeå, Sweden. She was Assistant Professor (equivalent) in Inorganic Chemistry at the University of Umeå before coming to Stanford, initially as Senior Academic Scientific Staff, followed by appointed as Professor (Research) in 2002, and Professor of Photon Science in 2007. -
Johannes Bodo Heekerens
Affiliate, Psychology
BioI am a clinical psychologist studying the nature of human well-being and ways to improve it. My current research focus is on dissociation and affect regulation. I am currently a visiting scholar at Stanford University’s Psychophysiology Lab, supported by a fellowship from the Deutsche Forschungsgemeinschaft (DFG). Additionally, I am a research fellow at Charité – Universitätsmedizin Berlin. I earned my Ph.D. in psychology from Freie Universität Berlin and am also a German board-certified cognitive-behavioral psychotherapist, having completed my training at the Zentrum für Psychotherapie der Humboldt-Universität zu Berlin.
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Gregory M. Heestand, MD
Clinical Associate Professor, Medicine - Oncology
BioDr. Heestand is a board-certified medical oncologist with a focus on gastrointestinal cancers, primarily hepatocellular carcinoma, cholangiocarcinoma, and gallbladder cancer. He serves as the medical oncology champion of the Stanford Hepatobiliary Tumor Board, as well as the principal investigator of multiple clinical trials. He collaborates with campus laboratories to help develop new biomarker and treatment technologies. He is the former director of the Stanford Oncology Fellowship Program.
Dr. Heestand and his team take great pride in helping patients and their families face gastrointestinal cancer.
Outside of the clinic, Dr. Heestand enjoys playing the piano, teaching his kids about music, cooking for friends and family, and surfing the internet for interesting things to read. -
Katherine (Heflin) Hefcart
Affiliate, Department Funds
Resident in Psychiatry and Behavioral SciencesBioAdult Psychiatry Resident, focusing on Community/Public Psychiatry, LGBTQ+ competent care, integrative mental health, and reproductive psychiatry. Attended Stanford undergraduate ('11), Harvard T.H. Chan School of Public Health ('15), Dartmouth Geisel Medical School ('23).
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Nuriya Ruth Hefron
Training & Technical Assistance Manager, Psych/Public Mental Health & Population Sciences
Current Role at StanfordProgram Manager INSPIRE 360
Expansion of Early Psychosis Care Program -
Sam Heft-Neal
Senior Research Scholar
BioSam Heft-Neal is a Senior Research Scholar at the Center on Food Security and the Environment. Sam is working to identify the impacts of environmental changes on health, agriculture, and food availability around the world. His recent work combines household surveys with remote sensing data to examine environmental drivers of child health. Sam holds a Ph.D. in Agricultural and Resource Economics from the University of California, Berkeley and a B.A. in Statistics and Economics from the same institution.
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John P. Hegarty II
Clinical Assistant Professor, Psychiatry and Behavioral Sciences
BioI am a neuroscientist and Principal Investigator of the Stanford Clinical Neuroscience (CNS) Lab in the Department of Psychiatry and Behavioral Sciences as well as Director of Neuroimaging for the Autism and Developmental Disorders Research Program at Stanford. My innovative research studies clinical aspects of cognitive and behavioral neuroscience, with a special focus on examining the neural circuitry associated with important brain-behavior relationships that may underlie different psychological and psychiatric domains in autistic children, adolescents, and adults. The ultimate goal of this research is to improve our understanding of the development of different cognitive and behavioral skills in order to develop mechanistically driven interventions that will improve precision medicine for mental health. Biologically based diagnosis and treatment are extremely limited for most psychological and psychiatric conditions but also critically needed to increase early identification and improve treatment outcomes, especially for neurodevelopmental disorders in which early intervention is the most beneficial. My early career research has primarily focused on clinical neuroscience using neuroimaging (e.g., MRI & EEG) to examine the effects of different drugs and behavioral interventions on the brain, especially for developing biomarkers for improving treatment planning and monitoring biological changes in response to single dose and clinical trials.
My primary contributions to science thus far fall within these major categories: 1) identifying the neural correlates of individual differences in cognition and behavior, 2) developing new interventions and investigating the neurobiological substrates of response to treatment, 3) examining different factors that contribute to brain development, 4) summarizing and increasing accessibility to autism-related research, and 5) methods development for neuroimaging studies. My earliest research investigated the neurobiology of alexithymia, dyslexia, and stress using structural and functional magnetic resonance imaging to test theories of the mechanisms that contribute to differences in cognition and behavior. My subsequent dissertation research, in which I began to focus on neurodevelopmental disorders, examined the neural correlates of response to beta-blockers in autistic adults and also assessed the contribution of cerebellar circuits to the autism phenotype. During my postdoctoral training, I have developed further skills for working with children in multiple clinical research settings, especially for using advanced neuroimaging approaches to examine important brain-behavior relationships. This includes a recent K99/R00 from the National Institute of Child Health and Human Development (NCT04278898 & NCT05664789) that will assess the neurobiology of restricted and repetitive behaviors in autistic children and examine the efficacy and target engagement of a novel nutritional supplement and investigational drug, N-acetylcysteine (NAC), in the brain. You can find more information about our NAC studies at https://redcap.link/NACandAutism.
