1,216 research outputs found
Community Structure of the Macrobenthos in Back Bay, Virginia
A study of the subtidal macrobenthos in Back Bay, Virginia was conducted to examine community structure in relation to sedimentary and water quality characteristics. Samples were collected in August and November of 1987 and February and May of 1988 at ten stations.
From a cluster analysis of ten collection stations, three site groups were identified. Species composition between site groups was relatively homogeneous. Discriminant analysis indicated that eight species accounted for most of the variation between site groups. A comparison of plots of the biological and environmental variables in discriminant space suggested that variation in the biological data between site groups was related in part to silt-day content, organic cont~nt, and particle size of the sediment.
Three temporal groups were identified from a second cluster analysis of data averaged over all collection stations by collection date. Discriminant analysis indicated that six species accounted for most of the variation between temporal groups. Temporal variation in macrobenthic community structure was the result of reproductive and recruitment events of these six species.
Species diversity indices were similar to values obtained in oligohaline regions of the Chesapeake Bay (Dauer 1988; 1989). Community density was higher and community biomass was lower than values found in the Chesapeake Bay oligohaline areas (Dauer, 1988; 1989). Major changes in total community density and biomass were related to spatial and temporal changes in two dominant species: Chironomus riparius (Onsecta) and Scolecolepides viridis (Polychaeta)
The Dauer-Brown Letters: Towards a Comprehensive Legal Education
Edward A. Dauer is President of the National Center for Preventive Law at the University of Denver. Louis M. Brown developed and advocates preventive law jurisprudence. In this dialogue, drawn from an exchange of correspondence between them, Dauer and Brown focus their insights on how best to gear law school curricula to train lawyers to handle the complexities of a real life practice
Genetic Background Modulates the Phenotype of a Mouse Model of DYT1 Dystonia
DYT1 dystonia is a debilitating neurological disease characterized by involuntary twisting movements. The disease is caused by an in-frame deletion (GAG, “ΔE”) mutation in the TOR1A gene that encodes the torsinA protein. Intriguingly, only 30% of mutation carriers exhibit motor symptoms despite the fact that functional brain imaging studies show abnormal brain metabolism in all carriers. Because genetic modifiers may be a determinant of this reduced penetrance, we examined the genetic contribution of three different inbred strains of mice on the DYT1 mutation in animals that are homozygous (Tor1aΔE/ΔE) or heterozygous (Tor1aΔE/+; disease state) for the disease-causing ΔE mutation. We find that the DBA/2J, C57BL/6J, and CD1-ICR contribution of genes significantly alter lifespan in Tor1aΔE/ΔE mice, which die during the first few days of life on the 129S6/SvEvTac (129) background. The C57BL/6J (B6) strain significantly decreases life expectancy of Tor1aΔE/ΔE animals but, like 129S6/SvEvTac Tor1aΔE/+ mice, congenic C57BL/6J Tor1aΔE/+ mice do not exhibit any motor abnormalities. In contrast, the DBA/2J (D2) strain significantly increases life expectancy. This effect was not present in congenic DBA/2J Tor1aΔE/ΔE mice, indicating that the extended lifespan of F2 129/D2 mice was due to a combination of homozygous and heterozygous allelic effects. Our observations suggest that genetic modifiers may alter the penetrance of the ΔE mutation, and that mapping these modifiers may provide fresh insight into the torsinA molecular pathway
Report of IRPA task group on the impact of the eye lens dose limits
In 2012 IRPA established a task group (TG) to identify key issues in the implementation of the revised eye lens dose limit. The TG reported its conclusions in 2013. In January 2015, IRPA asked the TG to review progress with the implementation of the recommendations from the early report and to collate current practitioner experience. This report presents the results of a survey on the view of the IRPA professionals on the new limit to the lens of the eye and on the wider issue of tissue reactions. Recommendations derived from the survey are presented. This report was approved by IRPA Executive Council on 31 January 2017
Using art and story to explore how primary school students in rural Tanzania understand planetary health: a qualitative analysis
Background The global planetary health community increasingly recognises the need to prepare students to investigate and address connections between environmental change and human health. As we strive to support education on planetary health themes for students of all ages, understanding students’ concepts of linkages between the health of people and animals, and their shared environments might advance educational approaches. Children living in villages bordering Ruaha National Park in Iringa Region, Tanzania, have direct experience of these connections as they share a water-stressed but biodiverse environment with domestic animals and wildlife. Livelihoods in these villages depend predominantly on crop and livestock production, including extensive pastoralist livestock keeping. Through qualitative research, we aim to explore and describe Tanzanian primary school students’ understanding of connections between human health and the environment
Transference of Citizen Science Program Impacts: A Theory Grounded in Public Participation in Scientific Research
Citizen science is known for increasing the geographic, spatial, and temporal scale from which scientists can gather data. It is championed for its potential to provide experiential learning opportunities to the public. Documentation of educational outcomes and benefits for citizen scientists continues to grow. This study proposes an added benefit of these collaborations: the transference of program impacts to individuals outside of the program. The experiences of fifteen citizen scientists in entomology citizen science programs were analyzed using a constructivist grounded theory methodology. We propose the substantive-level theory of transference to describe the social process by which the educational and attitudinal impacts intended by program leaders for the program participants are filtered by citizen scientists and transferred to others. This process involves individual and external phases, each with associated actions. Transference occurred in participants who had maintained a long-term interest in nature, joined a citizen science program, shared science knowledge and experiences, acquired an expert role to others, and influenced change in others. Transference has implications for how citizen scientists are perceived by professional communities, understanding of the broader impacts and contributions of citizen science to wicked problems, program evaluation, and the design of these programs as informal science education opportunities
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