1,213 research outputs found
Isoscalar monopole excitations in O: -cluster states at low energy and mean-field-type states at higher energy
Isoscalar monopole strength function in O up to MeV is
discussed. We found that the fine structures at the low energy region up to
MeV in the experimental monopole strength function obtained
by the O reaction can be rather satisfactorily
reproduced within the framework of the cluster model, while the gross
three bump structures observed at the higher energy region ( MeV) look likely to be approximately reconciled by the mean-field
calculations such as RPA and QRPA. In this paper, it is emphasized that two
different types of monopole excitations exist in O; one is the monopole
excitation to cluster states which is dominant in the lower energy part ( MeV), and the other is the monopole excitation of the mean-field
type such as one-particle one-hole () which {is attributed} mainly to the
higher energy part ( MeV). It is found that this
character of the monopole excitations originates from the fact that the ground
state of O with the dominant doubly closed shell structure has a duality
of the mean-field-type {as well as} -clustering {character}. This dual
nature of the ground state seems to be a common feature in light nuclei.Comment: 35 pages, 5 figure
Division IX: Optical and infrared techniques
This document introduces the reports by the Commissions and Working Groups of Division IX. © 2007 International Astronomical Union
Damned if they do, damned if they don't: negotiating the tricky context of anti-social behaviour and keeping safe in disadvantaged urban neighbourhoods
Young people's relationship with anti-social behaviour (ASB) is complicated. While their behaviours are often stereotyped as anti-social (e.g. ‘hanging about’), they also experience ASB in their neighbourhood. In this study, we explore young people's own perspectives on ASB, comparing results from ‘go-along’ interviews and focus groups conducted in disadvantaged neighbourhoods in Glasgow, Scotland. This article discusses how young people's everyday experience of ASB was contextualised by social factors such as cultural stereotyping of marginalised groups, poor social connectivity and spatial marginalisation within their neighbourhood. Furthermore, we found that these social factors were mutually reinforcing and interacted in a way that appeared to leave young people in a ‘no-win’ situation regarding their association with ASB. Participation in ASB and attempts to avoid such involvement were seen to involve negative consequences: participation could entail violence and spatial restrictions linked to territoriality, but avoidance could lead to being ostracised from their peer group. Regardless of involvement, young people felt that adults stereotyped them as anti-social. Our findings therefore provide support for policies and interventions aimed at reducing ASB (perpetrated by residents of all ages); in part by better ensuring that young people have a clear incentive for avoiding such behaviours
Mesoscale eddies influence the movements of mature female white sharks in the Gulf Stream and Sargasso Sea
© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 7363, doi:10.1038/s41598-018-25565-8.Satellite-tracking of mature white sharks (Carcharodon carcharias) has revealed open-ocean movements spanning months and covering tens of thousands of kilometers. But how are the energetic demands of these active apex predators met as they leave coastal areas with relatively high prey abundance to swim across the open ocean through waters often characterized as biological deserts? Here we investigate mesoscale oceanographic variability encountered by two white sharks as they moved through the Gulf Stream region and Sargasso Sea in the North Atlantic Ocean. In the vicinity of the Gulf Stream, the two mature female white sharks exhibited extensive use of the interiors of clockwise-rotating anticyclonic eddies, characterized by positive (warm) temperature anomalies. One tagged white shark was also equipped with an archival tag that indicated this individual made frequent dives to nearly 1,000 m in anticyclones, where it was presumably foraging on mesopelagic prey. We propose that warm temperature anomalies in anticyclones make prey more accessible and energetically profitable to adult white sharks in the Gulf Stream region by reducing the physiological costs of thermoregulation in cold water. The results presented here provide valuable new insight into open ocean habitat use by mature, female white sharks that may be applicable to other large pelagic predators.This work was supported by the WHOI Ocean Life Institute and awards from NASA and NSF
Improved parametrization of Antarctic krill target strength models
Author Posting. © Acoustical Society of America, 2006. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 119 (2006): 232-242, doi:10.1121/1.2141229.There are historical discrepancies between empirical observations of Antarctic krill target strength and predictions using theoretical scattering models. These differences are addressed through improved understanding of key model parameters. The scattering process was modeled using the distorted-wave Born approximation, representing the shape of the animal as a bent and tapered cylinder. Recently published length-based regressions were used to constrain the sound speed and density contrasts between the animal and the surrounding seawater, rather than the earlier approach of using single values for all lengths. To constrain the parameter governing the orientation of the animal relative to the incident acoustic wave, direct measurements of the orientation of krill in situ were made with a video plankton recorder. In contrast to previous indirect and aquarium-based observations, krill were observed to orient themselves mostly horizontally. Averaging predicted scattering over the measured distribution of orientations resulted in predictions of target strength consistent with in situ measurements of target strength of large krill (mean length 40–43 mm) at four frequencies (43–420 kHz), but smaller than expected under the semi-empirical model traditionally used to estimate krill target strength.This project was
supported by NSF U.S. Antarctic Program Grant No. OPP-9910307. G. Lawson was supported by an Office of Naval
Research Graduate Traineeship Award in Ocean Acoustics (Grant No. N000 14-03-1-0212), a Fulbright Scholarship, a
Natural Sciences and Engineering Research Council of Canada Post-Graduate Scholarship, and the Woods Hole
Oceanographic Institution Academic Programs Office
Generating and testing ecological hypotheses at the pondscape with environmental DNA metabarcoding: A case study on a threatened amphibian
Background: Environmental DNA (eDNA) metabarcoding is revolutionizing biodiversity monitoring, but has unrealized potential for ecological hypothesis generation and testing. Aims: Here, we validate this potential in a large-scale analysis of vertebrate community data generated by eDNA metabarcoding of 532 UK ponds. Materials & Methods: We test biotic associations between the threatened great crested newt (Triturus cristatus) and other vertebrates as well as abiotic factors influencing T.cristatus detection at the pondscape. Furthermore, we test the status of T.cristatus as an umbrella species for pond conservation by assessing whether vertebrate species richness is greater in ponds with T.cristatus and higher T.cristatus Habitat Suitability Index (HSI) scores. Results: Triturus cristatus detection was positively correlated with amphibian and waterfowl species richness. Specifically, T.cristatus was positively associated with smooth newt (Lissotriton vulgaris), common coot (Fulica atra), and common moorhen (Gallinula chloropus), but negatively associated with common toad (Bufo bufo). Triturus cristatus detection did not significantly decrease as fish species richness increased, but negative associations with common carp (Cyprinus carpio), three-spined stickleback (Gasterosteus aculeatus), and ninespine stickleback (Pungitius pungitius) were identified. Triturus cristatus detection was negatively correlated with mammal species richness, and T.cristatus was negatively associated with gray squirrel (Sciurus carolinensis). Triturus cristatus detection was negatively correlated with larger pond area, presence of inflow, and higher percentage of shading, but positively correlated with HSI score, supporting its application to T.cristatus survey. Vertebrate species richness was significantly higher in T.cristatus ponds and broadly increased as T.cristatus HSI scores increased. Discussion: We reaffirm reported associations (e.g., T.cristatus preference for smaller ponds) but also provide novel insights, including a negative effect of pond inflow on T.cristatus. Conclusion: Our findings demonstrate the prospects of eDNA metabarcoding for ecological hypothesis generation and testing at landscape scale, and dramatic enhancement of freshwater conservation, management, monitoring, and research
Yield of Smear Microscopy and Radiological Findings of Male and Female Patients with Tuberculosis in Abuja, Nigeria
Objective. To describe the yield of smear-microscopy and radiological findings by male and female patients with symptoms of tuberculosis in Abuja, Nigeria. Methods. Patients ≥15 years old with cough for >3 weeks submitted 3 sputum samples for smear microscopy. One specimen was cultured using MGIT-960. All patients had lung X-rays and screened for HIV. Results. were more likely to be smear-positive than females (262/774 [34%] and 137/547 [25%], P < .01), but similar proportions of males and females were culture-positive (437/691 [63%] and 294/495 [59%], P = .09). 317/626 (50.6%) males and 249/419 (59.4%) females were HIV-positive (P < .005). Among culture-positives patients, HIV-infected males were less likely to have positive smears than HIV-negative males (49.2% versus 66%, P = .001). Among females, smear positivity did not vary with HIV (46.4% for HIV-positive and 52.9% for HIV-negative, P = .38). Of 274 culture-confirmed TB cases, 226 (82.5%) had cavities, and 271 (99%) had ≥1 lung areas affected. HIV-positive males were more likely to have lung cavities than HIV-positive females (85% versus 69%, P < .04) and to have ≥3 lung areas affected (P = .03).
Conclusion. Differences in the yield of smear-microscopy, culture and X-rays on presentation are due to several factors including HIV coinfection and gender
On-road Remote Sensing of Carbon Monoxide and Hydrocarbon Emissions During Several Vehicle Operating Conditions (Presentation)
Protein Geometry Database: a flexible engine to explore backbone conformations and their relationships to covalent geometry
The backbone bond lengths, bond angles, and planarity of a protein are influenced by the backbone conformation (φ,Ψ), but no tool exists to explore these relationships, leaving this area as a reservoir of untapped information about protein structure and function. The Protein Geometry Database (PGD) enables biologists to easily and flexibly query information about the conformation alone, the backbone geometry alone, and the relationships between them. The capabilities the PGD provides are valuable for assessing the uniqueness of observed conformational or geometric features in protein structure as well as discovering novel features and principles of protein structure. The PGD server is available at http://pgd.science.oregonstate.edu/ and the data and code underlying it are freely available to use and extend
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