Browsing by Subject "TIME"

Now showing 1 - 6 of 6
  • Thumbnail Image
    ItemOpen Access
    A plastid phylogeny of the cosmopolitan fern family cystopteridaceae (Polypodiopsida)
    (Systematic Botany, 2013-06-01) Rothfels, CJ; Windham, MD; Pryer, KM
    Among the novel results of recent molecular phylogenetic analyses are the unexpectedly close evolutionary relationships of the genera Acystopteris, Cystopteris, and Gymnocarpium, and the phylogenetic isolation of these genera from Woodsia. As a consequence, these three genera have been removed from Woodsiaceae and placed into their own family, the Cystopteridaceae. Despite the ubiquity of this family in rocky habitats across the northern hemisphere, and its cosmopolitan distribution (occurring on every continent except Antarctica), sampling of the Cystopteridaceae in phylogenetic studies to date has been sparse. Here we assemble a three-locus plastid dataset (matK, rbcL, trnG-R) that includes most recognized species in the family and multiple accessions of widespread taxa from across their geographic ranges. All three sampled genera are robustly supported as monophyletic, Cystopteris is strongly supported as sister to Acystopteris, and those two genera together are sister to Gymnocarpium. The Gymnocarpium phylogeny is deeply divided into three major clades, which we label the disjunctum clade, the robertianum clade, and core Gymnocarpium. The Cystopteris phylogeny, similarly, features four deeply diverged clades: C. montana, the sudetica clade, the bulbifera clade, and the fragilis complex. Acystopteris includes only three species, each of which is supported as monophyletic, with A. taiwaniana sister to the japonica/tenuisecta clade. Our results yield the first species-level phylogeny of the Cystopteridaceae and the first molecular phylogenetic evidence for species boundaries. These data provide an essential foundation for further investigations of complex patterns of geographic diversification, speciation, and reticulation in this family. © Copyright 2013 by the American Society of Plant Taxonomists.
  • Thumbnail Image
    ItemOpen Access
    Floquet Majorana fermions for topological qubits in superconducting devices and cold-atom systems.
    (Physical review letters, 2013-07) Liu, Dong E; Levchenko, Alex; Baranger, Harold U
    We develop an approach to realizing a topological phase transition and non-Abelian braiding statistics with dynamically induced Floquet Majorana fermions (FMFs). When the periodic driving potential does not break fermion parity conservation, FMFs can encode quantum information. Quasienergy analysis shows that a stable FMF zero mode and two other satellite modes exist in a wide parameter space with large quasienergy gaps, which prevents transitions to other Floquet states under adiabatic driving. We also show that in the asymptotic limit FMFs preserve non-Abelian braiding statistics and, thus, behave like their equilibrium counterparts.
  • Thumbnail Image
    ItemOpen Access
    Germline Genetic Testing: What the Breast Surgeon Needs to Know.
    (Annals of surgical oncology, 2019-07) Plichta, Jennifer K; Sebastian, Molly L; Smith, Linda A; Menendez, Carolyn S; Johnson, Anita T; Bays, Sussan M; Euhus, David M; Clifford, Edward J; Jalali, Mena; Kurtzman, Scott H; Taylor, Walton A; Hughes, Kevin S
    PURPOSE:The American Society of Breast Surgeons (ASBrS) sought to provide educational guidelines for breast surgeons on how to incorporate genetic information and genomics into their practice. METHODS:A comprehensive nonsystematic review was performed of selected peer-reviewed literature. The Genetics Working Group of the ASBrS convened to develop guideline recommendations. RESULTS:Clinical and educational guidelines were prepared to outline the essential knowledge for breast surgeons to perform germline genetic testing and to incorporate the findings into their practice, which have been approved by the ASBrS Board of Directors. RECOMMENDATIONS:Thousands of women in the USA would potentially benefit from genetic testing for BRCA1, BRCA2, and other breast cancer genes that markedly increase their risk of developing breast cancer. As genetic testing is now becoming more widely available, women should be made aware of these tests and consider testing. Breast surgeons are well positioned to help facilitate this process. The areas where surgeons need to be knowledgeable include: (1) identification of patients for initial breast cancer-related genetic testing, (2) identification of patients who tested negative in the past but now need updated testing, (3) initial cancer genetic testing, (4) retesting of patients who need their genetic testing updated, (5) cancer genetic test interpretation, posttest counseling and management, (6) management of variants of uncertain significance, (7) cascade genetic testing, (8) interpretation of genetic tests other than clinical cancer panels and the counseling and management required, and (9) interpretation of somatic genetic tests and the counseling and management required.
  • Thumbnail Image
    ItemOpen Access
    Links between physical and chemical weathering inferred from a 65-m-deep borehole through Earth's critical zone.
    (Scientific reports, 2019-03-14) Holbrook, W Steven; Marcon, Virginia; Bacon, Allan R; Brantley, Susan L; Carr, Bradley J; Flinchum, Brady A; Richter, Daniel D; Riebe, Clifford S
    As bedrock weathers to regolith - defined here as weathered rock, saprolite, and soil - porosity grows, guides fluid flow, and liberates nutrients from minerals. Though vital to terrestrial life, the processes that transform bedrock into soil are poorly understood, especially in deep regolith, where direct observations are difficult. A 65-m-deep borehole in the Calhoun Critical Zone Observatory, South Carolina, provides unusual access to a complete weathering profile in an Appalachian granitoid. Co-located geophysical and geochemical datasets in the borehole show a remarkably consistent picture of linked chemical and physical weathering processes, acting over a 38-m-thick regolith divided into three layers: soil; porous, highly weathered saprolite; and weathered, fractured bedrock. The data document that major minerals (plagioclase and biotite) commence to weather at 38 m depth, 20 m below the base of saprolite, in deep, weathered rock where physical, chemical and optical properties abruptly change. The transition from saprolite to weathered bedrock is more gradational, over a depth range of 11-18 m. Chemical weathering increases steadily upward in the weathered bedrock, with intervals of more intense weathering along fractures, documenting the combined influence of time, reactive fluid transport, and the opening of fractures as rock is exhumed and transformed near Earth's surface.
  • Thumbnail Image
    ItemOpen Access
    Physical Activity, Sedentary Behavior, and Retirement: The Multi-Ethnic Study of Atherosclerosis.
    (American journal of preventive medicine, 2018-06) Jones, Sydney A; Li, Quefeng; Aiello, Allison E; O'Rand, Angela M; Evenson, Kelly R
    Physical activity and sedentary behavior are major risk factors for chronic disease. These behaviors may change at retirement, with implications for health in later life. The study objective was to describe longitudinal patterns of moderate to vigorous and domain-specific physical activity and TV watching by retirement status.Participants in the Multi-Ethnic Study of Atherosclerosis (n=6,814) were recruited from six U.S. communities and were aged 45-84 years at baseline. Retirement status and frequency and duration of domain-specific physical activity (recreational walking, transport walking, non-walking leisure activity, caregiving, household, occupational/volunteer) and TV watching were self-reported at four study exams (2000 to 2012). Fixed effect linear regression models were used to describe longitudinal patterns in physical activity and TV watching by retirement status overall and stratified by socioeconomic position. Analyses were conducted in 2017.Of 4,091 Multi-Ethnic Study of Atherosclerosis participants not retired at baseline, 1,012 (25%) retired during a median of 9 years follow-up. Retirement was associated with a 10% decrease (95% CI= -15%, -5%) in moderate to vigorous physical activity and increases of 13% to 29% in recreational walking, household activity, and TV watching. Among people of low socioeconomic position, the magnitude of association was larger for moderate to vigorous physical activity. Among people of high socioeconomic position, the magnitude of association was larger for non-walking leisure and household activity.The retirement transition was associated with changes in physical activity and TV watching. To inform intervention development, future research is needed on the determinants of behavior change after retirement, particularly among individuals of low socioeconomic position.
  • Thumbnail Image
    ItemOpen Access
    The dynamics of behavior: Review of Sutton and Barto: Reinforcement Learning : An Introduction (2 nd ed.)
    (Journal of the Experimental Analysis of Behavior, 2020-03) Staddon, JER