1,271 research outputs found
Missing Lensed Images and the Galaxy Disk Mass in CXOCY J220132.8-320144
The CXOCY J220132.8-320144 system consists of an edge-on spiral galaxy
lensing a background quasar into two bright images. Previous efforts to
constrain the mass distribution in the galaxy have suggested that at least one
additional image must be present (Castander et al. 2006). These extra images
may be hidden behind the disk which features a prominent dust lane. We present
and analyze Hubble Space Telescope (HST) observations of the system. We do not
detect any extra images, but the observations further narrow the observable
parameters of the lens system. We explore a range of models to describe the
mass distribution in the system and find that a variety of acceptable model
fits exist. All plausible models require 2 magnitudes of dust extinction in
order to obscure extra images from detection, and some models may require an
offset between the center of the galaxy and the center of the dark matter halo
of 1 kiloparsec. Currently unobserved images will be detectable by future James
Webb Space Telescope (JWST) observations and will provide strict constraints on
the fraction of mass in the disk.Comment: 10 pages, 8 figures, 6 tables. Minor changes, version accepted for
publication in Ap
The China shock and employment in portuguese firms
This paper considers the effects of Chinese import competition on firm-level labor market outcomes in Portugal. We examine direct competition in the Portuguese market and indirect competition Portugal's largest export markets in Western Europe. Using rich employer-employee data matched to firm-level trade transactions, we measure the degree to which different Portuguese firms faced Chinese import competition, based on firm product mix and distribution of sales across countries. We find economically and statistically significant employment declines in firms with more exposure to Chinese competition in European export markets, but minimal effects of direct competition in Portugal. Our findings also suggest a centrally important role for Portugal's stringent labor market regulations in limiting firms' ability to adjust to competitive shocks. In our earlier sample period (1995-2000), firms have limited ability to adjust employment, hours, or wages, and the primary adjustment margin is firm exit. In the later period (2000-2007), when more flexible temporary contracts comprise a larger share of employment, we find employment reductions among more exposed firms. Those employment reductions are entirely accounted for by changes in temporary employment, with no effect on permanent employment. We expect these findings to be informative for other peripheral European countries that had specialized in labor-intensive manufacturing industries operating under inflexible labor market regimes.info:eu-repo/semantics/publishedVersio
Dietary treatment of Crohnâs disease: perceptions of families with children treated by exclusive enteral nutrition, a questionnaire survey
Background: Diet is strongly associated with the aetiology of Crohnâs Disease (CD) and exclusive enteral nutrition (EEN) is the primary induction treatment in paediatric CD. This study explored opinions around the use of EEN and alternative novel, solid food-based diets (SFDs) expressed by paediatric patients with CD, previously treated with EEN and their parents. Methods: This anonymous questionnaire surveyed families of CD patients treated with EEN over 1 year. Two questionnaire forms were completed; one asking the patientsâ opinions and another referring to their main carer. This questionnaire explored participantsâ demographic characteristics; acceptability of a repeat EEN course to treat a future flare (EEN repeat); their opinion on how difficult EEN would be compared to an example SFD; and their intention to participate in a future clinical trial assessing the therapeutic efficacy of an SFD in CD. Results: Forty-one families of CD patients were approached with 29 sending replies (71%). Most of our participants were positive on completing another EEN course, however the majority would choose an SFD alternative (Patients: 66, Parents:72%). Both patients and their parents rated EEN to be more difficult to adhere to compared to an example SFD (p < 0.05), and their ratings were strongly correlated (EEN:r = 0.83, SFD:r = 0.75, p < 0.001). The majority of our respondents would agree to participate in a clinical trial assessing an SFDâs effectiveness (Patients:79, Parents:72%) for the management of active CD. Conclusions: While patients with CD and their families would accept an EEN repeat, the majority would prefer an SFD alternative. CD families surveyed are supportive of the development of solid food-based dietary treatments
A Distinct Intron-DNA Structure in Simian Virus 40 T-Antigen and Adenovirus 2 E1A Genes
Distinct structures delineating the introns of simian virus 40 T-antigen and adenovirus 2 E1A genes have been discovered. The structures, which are centered around the branch points of the genes inserted in supercoiled double-stranded plasmids, are specifically targeted through photoactivated strand cleavage by the metal complex tris(4,7-diphenyl-1,10-phenanthroline)rhodium(III). The DNA sites that are recognized lack sequence homology but are similar in demarcating functionally important sites on the
RNA level. The single-stranded DNA fragment corresponding to the coding strand of the E1A gene was also found to fold into a structure apparently identical to that in the supercoiled E1A gene based on the recognition by the metal complex. Further investigation of different single-stranded DNA fragments showed that the structure requires the sequences at both ends of the intron plus the flanking sequences but not the middle of the intron. These results provide direct evidence that the positions of these introns are structurally encoded on the DNA level
Modeling Marine Protected Areas for Threatened Eiders in a Climatically Changing Bering Sea
Delineating protected areas for sensitive species is a growing challenge as changing climate alters the geographic pattern of habitats as well as human responses to those shifts. When human impacts are expected within projected ranges of threatened species, there is often demand to demarcate the minimum habitat required to ensure the species\u27 persistence. Because diminished or wide-ranging populations may not occupy all viable (and needed) habitat at once, one must identify thresholds of resources that will support the species even in unoccupied areas. Long-term data on the shifting mosaic of critical resources may indicate ranges of future variability. We addressed these issues for the Spectacled Eider (Somateria fischeri), a federally threatened species that winters in pack ice of the Bering Sea. Changing climate has decreased ice cover and severely reduced the eiders\u27 benthic prey and has increased prospects for expansion of bottom trawling that may further affect prey communities. To assess long-term changes in habitats that will support eiders, we linked data on benthic prey, sea ice, and weather from 1970 to 2001 with a spatially explicit simulation model of eider energy balance that integrated field, laboratory, and remote-sensing studies. Areas estimated to have prey densities adequate for eiders in 1970â1974 did not include most areas that were viable 20 years later (1993â1994). Unless the entire area with adequate prey in 1993â1994 had been protected, the much reduced viable area in 1999â2001 might well have been excluded. During long non-foraging periods (as at night), eiders can save much energy by resting on ice vs. floating on water; thus, loss of ice cover in the future might substantially decrease the area in which prey densities are adequate to offset the eiders\u27 energy needs. For wide-ranging benthivores such as eiders, our results emphasize that fixed protected areas based on current conditions can be too small or inflexible to subsume long-term shifts in habitat conditions. Better knowledge of patterns of natural disturbance experienced by prey communities, and appropriate allocation of human disturbance over seasons or years, may yield alternative strategies to large-scale closures that may be politically and economically problemati
Internet-based Intervention to Improve Dietary Habits in Women of Color: SAving Lives Staying Active (SALSA)
Background: The Internet is an inexpensive method to distribute information that spans large distances. With 2/3 of the country currently overweight or obese, the Internet is the obvious choice to delivering health information to those that need it most. Purpose: The aim of this study was to determine the effectiveness of an Internet-based intervention to increase fruit and vegetable (FV) and decrease fat consumption in women of color. Method: Women (N=50) were middle-aged (M=41.2 years, SD=9.6), overweight (M=29.6 kg/m2, SD=5.3) and well educated (74% were college graduates). Participants completed measures of FV and fat consumption at 4 time points (spaced 4 weeks apart). All were randomized to a (1) 4-week web-based dietary education or (2) bi-weekly Latin dance group. After 4 weeks of intervention, women switched groups to ensure that everyone received both treatments. Women logged onto the SALSA website, where information on improving dietary habits, tools and activities were posted weekly. A total number of visits was logged for each participant and coded as visited less than once a week or one or more times per week for analyses. Results: Women were not meeting FV (M=4.2 servings, SD=5.2) or fat (M=30.9% kcal from fat, SD=3.1) consumption recommendations at baseline, with no differences between groups. Women who visited the site at least once per week increased FV consumption over time (F (3,93)=.587, p=.019) compared to women who did not visit the site at least once a week, regardless of intervention order. Women who visited the website as the first intervention saw greater decreases in fat consumption (p=.046). Conclusion: Greater access and awareness of dietary habits information online increased FV consumption and decreased fat consumption. Internet-based interventions may be used in at least some groups of women of color to change dietary habits. Future studies are needed to determine which website features are most important for behavior change
Walruses Attack Spectacled Eiders Wintering in Pack Ice of the Bering Sea
We observed walruses (Odobenus rosmarus) pursuing spectacled eiders (Somateria fischeri) within pack ice of the Bering Sea, 70â90 km from the nearest land. We used both direct observations from a helicopter and a heligimbal camera system that can film animals from a helicopter at high altitudes. The eiders were in monospecific flocks of thousands of birds within large leads. The walruses apparently tried to catch the eiders from below; the eiders responded with a âflash expansionâ (explosive radial movement), wing-flapping and running along the water surface to escape. Disturbance by individual walruses could restrict flocks of thousands of birds to small portions of the open water. In eight such events that we witnessed over 75 min of observations, we were unable to confirm that walruses captured any of these full-grown, flight-capable eiders. However, the high rate of attacks and the eidersâ dramatic escape response suggest that walruses can at times be effective predators on them, and may affect the eidersâ dispersion and energy balance.Nous avons observĂ© des morses (Odobenus rosmarus) en train de pourchasser des eiders Ă lunettes (Somateria fischeri) sur la banquise de la mer de BĂ©ring, soit Ă une distance de 70 Ă 90 kilomĂštres de la terre ferme la plus prĂšs. Nous nous sommes servis Ă la fois dâobservations directes faites Ă partir dâun hĂ©licoptĂšre et dâun appareil hĂ©ligimbal capable de filmer les animaux Ă partir dâun hĂ©licoptĂšre Ă haute altitude. Les eiders se tenaient en bandes monospĂ©cifiques constituĂ©es de milliers dâoiseaux faisant partie de gros groupements. Il semblait que les morses essayaient dâattraper les eiders par en-dessous; les eiders rĂ©agissaient en faisant une « expansion Ă©clair » (un mouvement radial explosif), en battant des ailes et en courant le long de la surface de lâeau afin de sâĂ©chapper. Les perturbations exercĂ©es par les morses individuels pouvaient avoir pour effet de restreindre les bandes de milliers dâoiseaux Ă de petites nappes dâeau libre. Dans huit cas de telle nature dont nous avons Ă©tĂ© tĂ©moins pendant plus de 75 minutes dâobservation, nous nâavons pas Ă©tĂ© en mesure de confirmer si les morses avaient rĂ©ussi Ă capturer des eiders adultes en Ă©tat de voler. Cependant, le taux Ă©levĂ© dâattaques de mĂȘme que la rĂ©action dramatique des eiders qui tentaient de sâĂ©chapper laissent entrevoir que les morses pourraient ĂȘtre des prĂ©dateurs efficaces en ce qui les concerne, ce qui pourrait exercer une influence sur lâexpansion des eiders et sur leur bilan Ă©nergĂ©tique
Ultrafast carrier phonon dynamics in NaOH-reacted graphite oxide film
NaOH-reacted graphite oxide film was prepared by decomposing epoxy groups in
graphite oxide into hydroxyl and -ONa groups with NaOH solution. Ultrafast
carrier dynamics of the sample were studied by time-resolved transient
differential reflection (\DeltaR/R). The data show two exponential relaxation
processes. The slow relaxation process (\sim2ps) is ascribed to low energy
acoustic phonon mediated scattering. The electron-phonon coupling and
first-principles calculation results demonstrate that - OH and -ONa groups in
the sample are strongly coupled. Thus, we attribute the fast relaxation process
(\sim0.17ps) to the coupling of hydroxyl and -ONa groups in the sample
Molecular Epidemiology of Escherichia coli Producing CTX-M and pAmpC ÎČ-Lactamases from Dairy Farms Identifies a Dominant Plasmid Encoding CTX-M-32 but No Evidence for Transmission to Humans in the Same Geographical Region
Third-generation cephalosporin resistance (3GC-R) in Escherichia coli is a rising problem in human and farmed-animal populations. We conducted whole-genome sequencing analysis of 138 representative 3GC-R isolates previously collected from dairy farms in southwest England and confirmed by PCR to carry acquired 3GC-R genes. This analysis identified bla(CTX-M) (131 isolates encoding CTX-M-1, -14, -15, -and 32 and the novel variant CTX-M-214), bla(CMY-2) (6 isolates), and bla(DHA-1) (1 isolate). A highly conserved plasmid was identified in 73 isolates, representing 27 E. coli sequence types. This novel âŒ220-kb IncHI2 plasmid carrying bla(CTX-M-32) was sequenced to closure and designated pMOO-32. It was found experimentally to be stable in cattle and human transconjugant E. coli even in the absence of selective pressure and was found by multiplex PCR to be present on 26 study farms representing a remarkable range of transmission over 1,500 square kilometers. However, the plasmid was not found among human urinary E. coli isolates we recently characterized from people living in the same geographical location, collected in parallel with farm sampling. There were close relatives of two bla(CTX-M) plasmids circulating among eight human and two cattle isolates, and a closely related bla(CMY-2) plasmid was found in one cattle and one human isolate. However, phylogenetic evidence of recent sharing of 3GC-R strains between farms and humans in the same region was not found. IMPORTANCE Third-generation cephalosporins (3GCs) are critically important antibacterials, and 3GC resistance (3GC-R) threatens human health, particularly in the context of opportunistic pathogens such as Escherichia coli. There is some evidence for zoonotic transmission of 3GC-R E. coli through food, but little work has been done examining possible transmission via interaction of people with the local near-farm environment. We characterized acquired 3GC-R E. coli found on dairy farms in a geographically restricted region of the United Kingdom and compared these with E. coli from people living in the same region, collected in parallel. While there is strong evidence for recent farm-to-farm transmission of 3GC-R strains and plasmidsâincluding one epidemic plasmid that has a remarkable capacity to be transmittedâthere was no evidence that 3GC-R E. coli found on study farms had a significant impact on circulating 3GC-R E. coli strains or plasmids in the local human population
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