1,566 research outputs found
Effects of macrofauna on acoustic backscatter from the seabed: Field manipulations in West Sound, Orcas Island, Washington, U.S.A.
Previous observations with a bottom-mounted, radially scanning sonar (BAMS) at 40 kHz suggested that macrofaunal activities influence low-angle, acoustic backscatter from seafloor sediments. In order to test that possibility experimentally, we measured and modeled time series of backscatter strength at both 40 and 300 kHz prior to manipulation and then introduced several macrofaunal species at known abundances to randomly selected locations within the ensonified area. We worked in West Sound, Orcas Island, Washington, at a water depth of 20.4 m and for the more frequently recorded 40-kHz series extracted effects by the time-series method known as intervention analysis, wherein the intervention was the experimental alteration. We observed increased backscatter from patches of the small protobranch bivalve Acila castrensis, and of the cockle Clinocardium nuttali, from bait used as chum for fishes and crabs, and from tethered crabs (Cancer magister); other treatments showed no significant change. All of the effective treatments involved increased backscatter at 300 kHz from animals that have obvious hard parts or air bladders. Power calculations for intervention analysis and geoacoustic modeling suggest that failure of other treatments to show significant effects on backscatter strength stems from the small size of the organisms and structures used relative to the 40-kHz wavelength (3.7 cm) and to low sound-speed contrasts between surficial sediments at this site and overlying water (at both frequencies), producing low backscatter levels from both volume heterogeneity and surface microtopography. This experiment demonstrates, however, that low-angle acoustic backscatter can be used to observe at least some populations of benthic animals over a large area (ca. 8000 m2) and that intervention analysis can be a useful tool where logistics permit repeated observation but few or no spatial replicates—frequently the case in ecological manipulations
Popular music, psychogeography, place identity and tourism: The case of Sheffield
Tourism and cultural agencies in some English provincial cities are promoting their popular music ‘heritage’ and, in some cases, contemporary musicians through the packaging of trails, sites, ‘iconic’ venues and festivals. This article focuses on Sheffield, a ‘post-industrial’ northern English city which is drawing on its associations with musicians past and present in seeking to attract tourists. This article is based on interviews with, among others, recording artists, promoters, producers and venue managers, along with reflective observational and documentary data. Theoretical remarks are made on the representations of popular musicians through cultural tourism strategies, programmes and products and also on the ways in which musicians convey a ‘psychogeographical’ sense of place in the ‘soundscape’ of the city
Adsorption of benzene on Si(100) from first principles
Adsorption of benzene on the Si(100) surface is studied from first
principles. We find that the most stable configuration is a
tetra--bonded structure characterized by one C-C double bond and four
C-Si bonds. A similar structure, obtained by rotating the benzene molecule by
90 degrees, lies slightly higher in energy. However, rather narrow wells on the
potential energy surface characterize these adsorption configurations. A
benzene molecule impinging on the Si surface is most likely to be adsorbed in
one of three different di--bonded, metastable structures, characterized
by two C-Si bonds, and eventually converts into the lowest-energy
configurations. These results are consistent with recent experiments.Comment: 4 pages, RevTex, 2 PostScript gzipped figure
韓国南部の水田における農業用殺虫剤撒布の数種蚊に対する毒性
A study carried out in rural areas of South Korea has revealed that farmer pesticide applications of fenitrothion, fenthion and certain other organophosphorus materials are highly toxic to mosquito larvae. The rates of application (0.3 to 0.9kg/ha), although not highly residual, are from 4 to 8 times higher than those required for Cu. tritaeniorhynchus control. The commonly used knapsack sprayer provides very thorough coverage on small (≤ 1ha) farmer plots. Application by power equipment and helicopters also provides excellent larval control. In comparison to previous years, the marked increase in pesticide usage may be a partial explanation for the much lower incidence of Japanese encephalitis in rural area.韓国南部の農村で行なった研究から,農民が撒布するフェニトロチオン,バイテックス及びその他の二,三の有機燐剤は蚊の幼虫に対して極めて有効であることがわかった.0.3-0.9kg/haの撒布は,残留性は大きくないけれども,コガタアカイエカの防除に必要な量の4-8倍に達する.普通に用いられている背負式噴霧機は狭い区画(1ha以下)に徹底して撒布するのに便利である.動力噴霧機やヘリコプターによる撒布もまた蚊の防除に優れた効果を示す.前年までと比較して,殺虫剤の使用量が増加したことが,農村での日本脳炎患者数の減少の1つの原因かもしれない
Veterinary students' views on animal patiens and human clients, using Q methodology
Veterinarians serve two masters: animal patients and human clients. Both animal patients and human clients have legitimate interests, and conflicting moral claims may flow from these interests. Earlier research concludes that veterinary students are very much aware of the complex and often paradoxical relationship they have and will have with animals. In this article the views of veterinary students about their anticipated relationship with animal patients and human clients are studied. The main part of the article describes discourses of first-year and fourth-year students about their (future) relationship with animals and their caretakers, for which Q-methodology is used. At the end of the article, the discourses are related to the students' gender and their workplace preferences. © 2007 AAVMC
The IUCF Cooler Project
This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440
The Hidden Curriculum of Veterinary Education: Mediators and Moderators of Its Effects
The “hidden curriculum” has long been supposed to have an effect on students' learning during their clinical education, and in particular in shaping their ideas of what it means to be a professional. Despite this, there has been little evidence linking specific changes in professional attitudes to the individual components of the hidden curriculum. This study aimed to recognize those components that led to a change in students' professional attitudes at a UK veterinary school, as well as to identify the attitudes most affected. Observations were made of 11 student groups across five clinical rotations, followed by semi-structured interviews with 23 students at the end of their rotation experience. Data were combined and analyzed thematically, taking both an inductive and deductive approach. Views about the importance of technical competence and communication skills were promoted as a result of students' interaction with the hidden curriculum, and tensions were revealed in relation to their attitudes toward compassion and empathy, autonomy and responsibility, and lifestyle ethic. The assessment processes of rotations and the clinical service organization served to communicate the messages of the hidden curriculum, bringing about changes in student professional attitudes, while student-selected role models and the student rotation groups moderated the effects of these influences
Self-build in the UK and Netherlands:mainstreaming self-development to address housing shortages?
This paper examines approaches to self or custom-build in the Netherlands and the UK to offer comparative insights into self- and custom-built housing contexts and cultures, and specifically, the relationships with local and strategic planning arrangements. The paper reviews arguments for self-build as a means to address housing shortages and examines the evidence of completions in practice. It positions the discussion in light of arguments that self-build can become a mainstream source of housing provision. The paper critically considers the role of think tanks in advocating housing policy solutions. Adopting a social constructionist perspective, the paper examines the work of the National Self-Build Association which has devised and implemented an action plan to promote the growth of self-build housing in the UK. Almere, which is located east of Amsterdam, is one of the case studies explored to inform thinking around self-build in the devolved UK. The conclusions tease out some of the implications for democratic and technocratic arguments around self-development and the right to design and build one’s home
Modifying the m6A brain methylome by ALKBH5-mediated demethylation: a new contender for synaptic tagging
Synaptic plasticity processes, which underlie learning and memory formation, require RNA to be translated local to synapses. The synaptic tagging hypothesis has previously been proposed to explain how mRNAs are available at specific activated synapses. However how RNA is regulated, and which transcripts are silenced or processed as part of the tagging process is still unknown. Modification of RNA by N6-methyladenosine (m6A/m) influences the cellular fate of mRNA. Here, by advanced microscopy, we showed that m6A demethylation by the eraser protein ALKBH5 occurs at active synaptic ribosomes and at synapses during short term plasticity. We demonstrated that at activated glutamatergic post-synaptic sites, both the YTHDF1 and YTHDF3 reader and the ALKBH5 eraser proteins increase in co-localisation to m6A-modified RNAs; but only the readers showed high co-localisation to modified RNAs during late-stage plasticity. The YTHDF1 and YTHFDF3 readers also exhibited differential roles during synaptic maturation suggesting that temporal and subcellular abundance may determine specific function. m6A-sequencing of human parahippocampus brain tissue revealed distinct white and grey matter m6A methylome profiles indicating that cellular context is a fundamental factor dictating regulated pathways. However, in both neuronal and glial cell-rich tissue, m6A effector proteins are themselves modified and m6A epitranscriptional and posttranslational modification processes coregulate protein cascades. We hypothesise that the availability m6A effector protein machinery in conjunction with RNA modification, may be important in the formation of condensed synaptic nanodomain assemblies through liquid-liquid phase separation. Our findings support that m6A demethylation by ALKBH5 is an intrinsic component of the synaptic tagging hypothesis and a molecular switch which leads to alterations in the RNA methylome, synaptic dysfunction and potentially reversible disease states
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