910 research outputs found
An Ethical framework for interpreting the United States Endangered Species Act
In this study I argue that a holistic approach is better than an individualistic approach for interpreting the United States Endangered Species Act (ESA). I propose that the use of a holistic ethical framework, based on fundamental environmental philosophy, is better in that it more effectively fulfills the ESA\u27s goals of species and ecosystem conservation. Holistic ethics is based on concern for a community as a whole, while individualistic ethics is based on concern for the individual. A holistic approach, I argue, is more beneficial to nature than is an individualistic approach or other non-holistic approaches. I set up basic criteria for determining the effectiveness of recovery plans for species, and I use those criteria to review eight cases of threatened and endangered species listed under the ESA. I conclude that holistic approaches are parallel with ecosystem management techniques and should be used in the protection of both species and ecosystems rather than non-holistic approaches
Characterization of sequences associated with position-effect variegation at pericentric sites in Drosophila heterochromatin
In a variety of organisms, euchromatic genes brought into juxtaposition with pericentric heterochromatin show position-effect variegation (PEV), a silencing of gene expression in a subset of the cells in which the gene is normally expressed. Previously, a P-element mobilization screen identified transgenic Drosophila stocks showing PEV of an hsp70-white+ reporter gene; transgenes in many of these stocks map to the chromocenter of polytene chromosome. A screen at an elevated temperature identified two stocks that under standard culture temperatures show complete repression of the hsp70-white+ transgene. The transgenes in both cases map to the chromocenter of polytene chromosomes. Different types of middle repetitive elements are adjacent to seven pericentric transgenes; unique sequences are adjacent to two of the perimetric transgenes. All of the transgenes show suppression of PEV in response to a mutation in the gene encoding heterochromatin protein 1 (HP1). This suppression correlates with a more accessible chromatin structure. The results indicate that a pericentric transgene showing PEV can be associated with different types of DNA sequences, while maintaining a common association with the chromosomal protein HP1
Preliminary Heat Capacity and Vapor Pressure Measurements of 2D 4He on ZYX Graphite
We report preliminary heat capacity and vapor pressure measurements of the
first and second layers of 4He adsorbed on ZYX graphite. ZYX is known to have
much better crystallinity than Grafoil, the most commonly-used exfoliated
graphite substrate, such as a ten-times larger platelet size. This allows us to
distinguish different phases in 2D helium-4 much more clearly and may provide
qualitatively different insights into this system. We found a significantly
asymmetric density-dependence of the heat-capacity peak associated with the 1/3
phase formation comparing with that obtained with Grafoil. The 2nd-layer
promotion density is determined as 11.8+-0.3 nm-2 from the heat-capacity
measurement of low density samples in the 2nd layer and vapor pressure
measurement.Comment: 7 pages, 7 figures, accepted for publication in JLTP - QFS201
An actin-related protein in Drosophila colocalizes with heterochromatin protein 1 in pericentric heterochromatin
The actin-related proteins have been identified by virtue of their sequence similarity to actin. While their structures are thought to be closely homologous to actin, they exhibit a far greater range of functional diversity. We have localized the Drosophila actin-related protein, Arp4, to the nucleus. It is most abundant during embryogenesis but is expressed at all developmental stages. Within the nucleus Arp4 is primarily localized to the centric heterochromatin. Polytene chromosome spreads indicate it is also present at much lower levels in numerous euchromatic bands. The only other protein in Drosophila reported to be primarily localized to centric heterochromatin in polytene nuclei is heterochromatin protein 1 (HP1), which genetic evidence has linked to heterochromatin-mediated gene silencing and alterations in chromatin structure. The relationship between Arp4 and heterochromatin protein 1 (HP1) was investigated by labeling embryos and larval tissues with antibodies to Arp4 and HP1. Arp4 and HP1 exhibit almost superimposable heterochromatin localization patterns, remain associated with the heterochromatin throughout prepupal development, and exhibit similar changes in localization during the cell cycle. Polytene chromosome spreads indicate that the set of euchromatic bands labeled by each antibody overlap but are not identical. Arp4 and HP1 in parallel undergo several shifts in their nuclear localization patterns during embryogenesis, shifts that correlate with developmental changes in nuclear functions. The significance of their colocalization was further tested by examining nuclei that express mutant forms of HP1. In these nuclei the localization patterns of HP1 and Arp4 are altered in parallel fashion. The morphological, developmental and genetic data suggest that, like HP1, Arp4 may have a role in heterochromatin functions. Keywords: Chromatin, Actin-related protein, Drosophila, Heterochromatin-protein 1, Position effect variegatio
Loss of murine Paneth cell function alters the immature intestinal microbiome and mimics changes seen in neonatal necrotizing enterocolitis
Necrotizing enterocolitis (NEC) remains the leading cause of gastrointestinal morbidity and mortality in premature infants. Human and animal studies suggest a role for Paneth cells in NEC pathogenesis. Paneth cells play critical roles in host-microbial interactions and epithelial homeostasis. The ramifications of eliminating Paneth cell function on the immature host-microbial axis remains incomplete. Paneth cell function was depleted in the immature murine intestine using chemical and genetic models, which resulted in intestinal injury consistent with NEC. Paneth cell depletion was confirmed using histology, electron microscopy, flow cytometry, and real time RT-PCR. Cecal samples were analyzed at various time points to determine the effects of Paneth cell depletion with and without Klebsiella gavage on the microbiome. Deficient Paneth cell function induced significant compositional changes in the cecal microbiome with a significant increase in Enterobacteriacae species. Further, the bloom of Enterobacteriaceae species that occurs is phenotypically similar to what is seen in human NEC. This further strengthens our understanding of the importance of Paneth cells to intestinal homeostasis in the immature intestine
The turn of the valve: representing with material models
Many scientific models are representations. Building on Goodman and Elginâs notion of representation-as we analyse what this claim involves by providing a general definition of what makes something a scientific model, and formulating a novel account of how they represent. We call the result the DEKI account of representation, which offers a complex kind of representation involving an interplay of, denotation, exemplification, keying up of properties, and imputation. Throughout we focus on material models, and we illustrate our claims with the Phillips-Newlyn machine. In the conclusion we suggest that, mutatis mutandis, the DEKI account can be carried over to other kinds of models, notably fictional and mathematical models
Policy Analytical Capacity Inside and Outside of Government: A Case Study of Colorado Climate and Energy Issues
This paper examines the policy analytical capacity
of government compared to the non-profit and private sectors
and to the research/academic community. Based on
original data from a 2011 questionnaire administered to
policy actors in the context of energy and climate issues in
the state of Colorado, the findings show that government is
not as âhollowed outâ as expected. While individuals from
academia and consulting firms may have higher analytical
capacity than government in conducting research, government
is higher across most other measures. Nonetheless,
nearly all respondents agree that government needs higher
levels of policy analytical capacity to address climate and
energy issues
Policy Analytical Capacity and Policy Activities
The study of policy process involves the study of
policy actors - people involved in the development of public
policy in a particular geographic area. This paper investigates
policy actors in the context of Colorado climate and
energy issues with a particular emphasis on the types and
levels of their engagement in policy activities. The conceptual
framework guiding this study centers on policy analytical
capacity, the ability to acquire and use information in the
policy process. High policy analytical capacity is expected to
be associated with high levels, and more diverse kinds, of
policy activities. The findings partly confirm the expectations.
Actors from government and the non-profit sector
report the highest policy analytical capacity and highest and
most diverse range of policy activities. However, researchers,
despite relatively high levels of policy analytical capacity,
report involvement in just a few activities beyond conducting
research. Actors with strong educational backgrounds in the
physical sciences are more likely to be involved in conducting
research whereas those with strong backgrounds in the
social sciences are more likely to be involved in evaluating
and appraising policies and working with the public. The
conclusion contextualizes the findings by focusing on the
relationship between technical and scientific complexity of
climate and energy issues and the necessity for participating
actors to possess high levels of policy analytical capacity
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