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914 results on '"Hopkins, David P."'

5. Biogeographic survey of soil bacterial communities across Antarctica

Author

Varliero, Gilda, Lebre, Pedro H., Adams, Byron, Chown, Steven L., Convey, Peter, Dennis, Paul G., Fan, Dandan, Ferrari, Belinda, Frey, Beat, Hogg, Ian D., Hopkins, David W., Kong, Weidong, Makhalanyane, Thulani, Matcher, Gwynneth, Newsham, Kevin K., Stevens, Mark I., Weigh, Katherine V., and Cowan, Don A.

Published
2024
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11. Surréalisme.

Author

HOPKINS, DAVID

Abstract

The article reviews the painting exhibition "Surréalisme," featuring works by various artists including Marcel Jean, André Masson, Max Ernst and Óscar Dominguez, at the Centre Pompidou in Paris, France from September 4, 2024 to January 13, 2025.

Published
2025

15. Seven Strong Claims about Successful School Leadership Revisited

Author

Leithwood, Kenneth, Harris, Alma, and Hopkins, David

Abstract

In 2008, the authors published an article in this journal entitled "Seven Strong Claims about Successful School Leadership" (Leithwood, Harris, and Hopkins 2008). The article was based on a major literature review that was summarised in a paper published by the National College for School Leadership in England. Both the National College paper and their subsequent article proved to be far more popular than they anticipated and both have been extensively cited over the past 10 years. This article revisits each of the seven claims, summarising what was said about each in the original publications, weighing each of the claims considering recent empirical evidence, and proposing revisions or refinements as warranted.

Published
2020
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19. Fragments of ML Decidable by Nested Data Class Memory Automata

Author

Cotton-Barratt, Conrad, Hopkins, David, Murawski, Andrzej S., and Ong, C. -H. Luke

Subjects
Computer Science - Programming Languages, Computer Science - Logic in Computer Science
Abstract

The call-by-value language RML may be viewed as a canonical restriction of Standard ML to ground-type references, augmented by a "bad variable" construct in the sense of Reynolds. We consider the fragment of (finitary) RML terms of order at most 1 with free variables of order at most 2, and identify two subfragments of this for which we show observational equivalence to be decidable. The first subfragment consists of those terms in which the P-pointers in the game semantic representation are determined by the underlying sequence of moves. The second subfragment consists of terms in which the O-pointers of moves corresponding to free variables in the game semantic representation are determined by the underlying moves. These results are shown using a reduction to a form of automata over data words in which the data values have a tree-structure, reflecting the tree-structure of the threads in the game semantic plays. In addition we show that observational equivalence is undecidable at every third- or higher-order type, every second-order type which takes at least two first-order arguments, and every second-order type (of arity greater than one) that has a first-order argument which is not the final argument.

Published
2015

21. Consequences of the COVID-19 pandemic for patients with metabolic diseases

Author

Bornstein, Stefan R., Rubino, Francesco, Ludwig, Barbara, Rietzsch, Hannes, Schwarz, Peter E. H., Rodionov, Roman N., Khunti, Kamlesh, Hopkins, David, Birkenfeld, Andreas L., Boehm, Bernhard, Amiel, Stephanie, Holt, Richard I. G., Skyler, Jay S., DeVries, J. Hans, Renard, Eric, Eckel, Robert H., Zimmet, Paul, Alberti, K. G., Geloneze, Bruno, Chan, Juliana C., Mbanya, Jean Claude, Onyegbutulem, Henry C., Ramachandran, Ambady, Basit, Abdul, Hassanein, Mohamed, Spinas, Giatgen A., Beuschlein, Felix, and Mingrone, Geltrude

Published
2021
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22. Taxonomic and Functional Diversity of Soil and Hypolithic Microbial Communities in Miers Valley, McMurdo Dry Valleys, Antarctica

Author

Wei, Sean TS, Lacap-Bugler, Donnabella C, Lau, Maggie CY, Caruso, Tancredi, Rao, Subramanya, de los Rios, Asunción, Archer, Stephen K, Chiu, Jill MY, Higgins, Colleen, Van Nostrand, Joy D, Zhou, Jizhong, Hopkins, David W, and Pointing, Stephen B

Subjects
Microbiology, Biological Sciences, Ecology, Antarctica, cyanobacteria, Dry Valleys, Geochip, hypolith, soil, Environmental Science and Management, Soil Sciences, Medical microbiology
Abstract

The McMurdo Dry Valleys of Antarctica are an extreme polar desert. Mineral soils support subsurface microbial communities and translucent rocks support development of hypolithic communities on ventral surfaces in soil contact. Despite significant research attention, relatively little is known about taxonomic and functional diversity or their inter-relationships. Here we report a combined diversity and functional interrogation for soil and hypoliths of the Miers Valley in the McMurdo Dry Valleys of Antarctica. The study employed 16S rRNA fingerprinting and high throughput sequencing combined with the GeoChip functional microarray. The soil community was revealed as a highly diverse reservoir of bacterial diversity dominated by actinobacteria. Hypolithic communities were less diverse and dominated by cyanobacteria. Major differences in putative functionality were that soil communities displayed greater diversity in stress tolerance and recalcitrant substrate utilization pathways, whilst hypolithic communities supported greater diversity of nutrient limitation adaptation pathways. A relatively high level of functional redundancy in both soil and hypoliths may indicate adaptation of these communities to fluctuating environmental conditions.

Published
2016

26. Local superfluid densities probed via current-induced superconducting phase gradients

Author

Hopkins, David S., Pekker, David, Wei, Tzu-Chieh, Goldbart, Paul M., and Bezryadin, Alexey

Subjects
Condensed Matter - Superconductivity
Abstract

We have developed a superconducting phase gradiometer consisting of two parallel DNA-templated nanowires connecting two thin-film leads. We have ramped the cross current flowing perpendicular to the nanowires, and observed oscillations in the lead-to-lead resistance due to cross-current-induced phase differences. By using this gradiometer we have measured the temperature and magnetic field dependence of the superfluid density and observed an amplification of phase gradients caused by elastic vortex displacements. We examine our data in light of Miller-Bardeen theory of dirty superconductors and a microscale version of Campbell's model of field penetration., Comment: 5 pages, 6 figures

Published
2007
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27. A Potential for Violent Injury: Guns and Knives in the Schools. Oregon Health Trends, Series No. 56.

Author

Oregon State Dept. of Human Resources, Portland. Health Div. and Hopkins, David

Abstract

This report focuses on the causative factors of violence in school children. It summarizes information about the demographic and mental health characteristics of students who carry weapons to school and includes comments from students on the reasons why they carry them, as well as what the research says. Results of the 1999 Youth Risk Behavior Survey, administered to 109 high schools in the state of Oregon who voluntarily participated, are highlighted throughout the report. The influence of television on risky behaviors among youth is considered. Prevention programs are discussed, including family education about gun safety, gun availability, and national legislation to help keep guns away from students. The report includes Table One, "Percentage of Students Who Carried Weapons during the Previous 30 Days, by Demographic and Behavioral Characteristics," and Table Two, "Selected Demographic and Behavioral Characteristics by Hours of Television Watching." (Contains 11 endnotes and 8 figures.) (JDM)

Published
2000

28. Operation of a superconducting nanowire quantum interference device with mesoscopic leads

Author

Pekker, David, Bezryadin, Alexey, Hopkins, David S., and Goldbart, Paul M.

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

A theory describing the operation of a superconducting nanowire quantum interference device (NQUID) is presented. The device consists of a pair of thin-film superconducting leads connected by a pair of topologically parallel ultra-narrow superconducting wires. It exhibits intrinsic electrical resistance, due to thermally-activated dissipative fluctuations of the superconducting order parameter. Attention is given to the dependence of this resistance on the strength of an externally applied magnetic field aligned perpendicular to the leads, for lead dimensions such that there is essentially complete and uniform penetration of the leads by the magnetic field. This regime, in which at least one of the lead dimensions lies between the superconducting coherence and penetration lengths, is referred to as the mesoscopic regime. The magnetic field causes a pronounced oscillation of the device resistance, with a period not dominated by the Aharonov-Bohm effect through the area enclosed by the wires and the film edges but, rather, in terms of the geometry of the leads, in contrast to the well-known Little-Parks resistance of thin-walled superconducting cylinders. A theory, encompassing this phenomenology, is developed through extensions, to the setting of parallel superconducting wires, of the Ivanchenko-Zil'berman-Ambegaokar-Halperin theory for the case of short wires and the Langer-Ambegaokar-McCumber-Halperin theory for the case of longer wires. It is demonstrated that the NQUID acts as a probe of spatial variations in the superconducting order parameter., Comment: 20 pages, 18 figures

Published
2005
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29. Suicidal Behavior: A Survey of Oregon High School Students, 1997.

Author

Oregon State Dept. of Human Resources, Portland. Health Div. and Hopkins, David

Abstract

Suicide is the second leading cause of death in the 10- to 19-year-old population in Oregon. The suicide rate has increased more than five-fold in the last three and one-half decades. This trend can be reversed by developing an understanding of the characteristics, behaviors, and events associated with suicide in at-risk youth. The Youth Risk Behavior Survey (YRBS) is one tool available to identify suicidal ideation and behavior. Fifty high schools were randomly selected to participate in the survey. This report describes demographic, environmental, and behavioral characteristics associated with suicide attempts. Survey results determined that suicide is a persistent problem among Oregon's youth. Among those who attempt suicide, there is a spectrum of desires, from cries for help to death. Many youth are ambivalent about ending their lives, and would rather live if a solution could be found. There is a continuum of self-destructiveness that can be measured in adolescents, and these behaviors and characteristics relate to premature adult mortality. The best individual behavioral characteristics for identifying high school students at risk of making suicide attempts are injection drug use, frequent use of inhalants, tobacco or cocaine, and multiple pregnancies. Appendixes include: (1) acknowledgement of participating schools; (2) YRBS questionnaire; (3) risky behavior and the home environment; (4) statistics of suicide attempts and deaths, 1994-1996; and (5) school-based health centers. Ways to help prevent teen suicide and limitations of this study are discussed. (Contains 68 references, 13 figures, and 12 tables.) (JDM)

Published
1998

35. School Improvement and Cultural Change: An Interim Account of the 'Improving the Quality of Education for All' (IQEA) Project.

Author

Hopkins, David

Abstract

This paper presents interim findings of the Improving the Quality of Education for All (IQEA) Project, a school-improvement and development project implemented by approximately 30 schools in East Anglia, North London, and Yorkshire in England. The overall project goal was to strengthen the school's ability to provide quality education for all students by building upon existing good practices. Following an overview of the project's principles, strategies, and school-improvement framework, a methodology for mapping change is presented. A conclusion is that school improvement works best when a clear and practical focus for development is linked to simultaneous work on the internal conditions within the schools. Conditions that underpin the work of successful schools include attention to enquiry and reflection; a commitment to collaborative planning and staff development; involvement of staff, students, and community in school policies; effective coordination strategies; and effective, shared leadership. The school-change techniques cluster around two key elements in the change process--school culture and the role of the individual teacher. The paper uses the metaphor of a "journey" to describe the progress of the project over time. The project is distinctive in that support, intervention, and research occur simultaneously. Three figures are included. (LMI)

Published
1994

36. U.S. Farm and Farm-Related Employment in 1988. How Large, Important, and Regionally Different? Agriculture Information Bulletin Number 634.

Author

Economic Research Service (USDA), Washington, DC., Majchrowicz, T. Alexander, and Hopkins, David E.

Abstract

Farm and farm-related industries account for almost 18 percent of total U.S. employment in 1988. This share is based on a broad definition of the agricultural sector, including not only farm production but also industries that mine, manufacture, and sell farm inputs; process commodities; and sell consumer goods. Many jobs in industries that support processing and distribution of farm goods are located far from the farm. Almost 71 percent of all farm and farm-related jobs are in metropolitan counties. Many of these jobs are in agricultural wholesale and retail trade industries that serve consumer markets in these counties. Only 722,000 farm and farm-related jobs are in the Northern Plains, the fewest of all regions, but the jobs in that thinly populated region account for 23.8 percent of its total employment. The 4.7 million farm and farm-related jobs in the Northeast, a populous part of the country, exceed those in other regions, but account for only 15.4 percent of the Northeast's total employment. In all regions, agriculture is relatively more important to non-metropolitan counties, where the proportion of total employment in farm and farm-related industries is 6.2 to 15.3 percent greater than in metropolitan counties. (Four figures and three tables are provided. An appended table provides a classification of farm and farm-related industries.) (YLB)

Published
1991

39. Genetic variation within a stick-insect species associated with community-level traits.

Author

Sinclair-Waters, Marion, Zamorano, Laura S, Gompert, Zachariah, Parchman, Tom, Tyukmaeva, Venera, Hopkins, David P, and Nosil, Patrik

Subjects
PHASMIDA, GENETIC variation, GENOME-wide association studies, ECOSYSTEM dynamics, PHENOTYPIC plasticity
Abstract

Phenotypic variation within species can affect the ecological dynamics of populations and communities. Characterizing the genetic variation underlying such effects can help parse the roles of genetic evolution and plasticity in "eco-evolutionary dynamics" and inform how genetic variation may shape patterns of evolution. Here, we employ genome-wide association (GWA) methods in Timema cristinae stick insects and their co-occurring arthropod communities to identify genetic variation associated with community-level traits. Previous studies have shown that maladaptation (i.e. imperfect crypsis) of T. cristinae can reduce the abundance and species richness of other arthropods due to an increase in bird predation. Whether genetic variation that is independent of crypsis has similar effects is unknown and was tested here using genome-wide genotyping-by-sequencing data of stick insects, arthropod community information, and GWA mapping with Bayesian sparse linear mixed models. We find associations between genetic variation in stick insects and arthropod community traits. However, these associations disappear when host-plant traits are accounted for. We thus use path analysis to disentangle interrelationships among stick-insect genetic variation, host-plant traits, and community traits. This revealed that host-plant size has large effects on arthropod communities, while genetic variation in stick insects has a smaller, but still significant effect. Our findings demonstrate that (1) genetic variation in a species can be associated with community-level traits but that (2) interrelationships among multiple factors may need to be analyzed to disentangle whether such associations represent causal relationships. This work helps to build a framework for genomic studies of eco-evolutionary dynamics. [ABSTRACT FROM AUTHOR]

Published
2024
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40. Strategies for Reducing Exposure to Environmental Tobacco Smoke, Increasing Tobacco-Use Cessation, and Reducing Initiation in Communities and Health-Care Systems: A Report on Recommendations of the Task Force on Community Preventive Services

Author

Hopkins, David P., Briss, Peter A., Harris, Jeffrey R., Ricard, Connie J., Rosenquist, J. Niels, Harris, Kate W., Husten, Corinne G., McKenna, Jeffrey W., Sharp, Donald J., Woollery, Trevor A., Sharma, Namita, and Pechacek, Terry F.

Published
2000

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