53,447 research outputs found
Photometric Redshifts for an Optical/Near-Infrared Catalogue in the Chandra Deep Field South
Photometric redshifts have proven a powerful tool in identifying galaxies
over a large range of lookback times. We have been generalising this technique
to incorporate the selection of candidate high redshift QSOs. We have applied
this to a large optical/near-infrared imaging survey in 6 wavebands aiming to
push farther in redshift (and fainter in luminosity) than previous studies. We
believe that study of these very faint and distant objects provides valuable
insights into galaxy formation and evolution.
Here we present work in progress and preliminary results for a catalogue of
objects detected as part of the Las Campanas Infrared Survey. This is a
stepping stone to the type of survey data that will become available in the
next few years from projects such as UKIDSS and VISTA.Comment: 4 pages LaTeX, submitted to the "Eurokiel 2002: Galaxy Evolution III:
From Simple Models to Self Consistant Approaches" Conference Proceeding
Systematic review of new medics’ clinical task experience by country
OBJECTIVES: There is a need for research which informs on the overall size and significance of clinical skills deficits among new medics, globally. There is also the need for a meta-review of the similarities and differences between countries in the clinical skills deficits of new medics.
DESIGN: A systematic review of published literature produced 68 articles from Google/Scholar, of which 9 met the inclusion criteria (quantitative clinical skills data about new medical doctors).
PARTICIPANTS: 1329 new medical doctors (e.g., foundation year-1s, interns, PGY1s).
SETTING: Ten countries/regions.
MAIN OUTCOME MEASURES: 123 data points and representation of a broad range of clinical procedures.
RESULTS: The average rate of inexperience with a wide range of clinical procedures was 35.92% (lower CI 30.84%, upper CI 40.99%). The preliminary meta-analysis showed that the overall deficit in experience is significantly different from 0 in all countries. Focusing on a smaller selection of clinical skills such as catheterisation, IV cannulation, nasogastric tubing and venepuncture, the average rate of inexperience was 26.75% (lower CI 18.55%, upper CI 35.54%) and also significant. England presented the lowest average deficit (9.15%), followed by New Zealand (18.33%), then South Africa (19.53%), Egypt, Kuwait, Gulf Cooperation Council countries and Ireland (21.07%), after which was Nigeria (37.99%), then USA (38.5%), and Iran (44.75%).
CONCLUSION: A meta-analysis is needed to include data not yet in the public domain from more countries. These results provide some support for the UK General Medical Council’s clear, detailed curriculum, which has been heralded by other countries as good practice
Nociceptive-Evoked Potentials Are Sensitive to Behaviorally Relevant Stimulus Displacements in Egocentric Coordinates.
Feature selection has been extensively studied in the context of goal-directed behavior, where it is heavily driven by top-down factors. A more primitive version of this function is the detection of bottom-up changes in stimulus features in the environment. Indeed, the nervous system is tuned to detect fast-rising, intense stimuli that are likely to reflect threats, such as nociceptive somatosensory stimuli. These stimuli elicit large brain potentials maximal at the scalp vertex. When elicited by nociceptive laser stimuli, these responses are labeled laser-evoked potentials (LEPs). Although it has been shown that changes in stimulus modality and increases in stimulus intensity evoke large LEPs, it has yet to be determined whether stimulus displacements affect the amplitude of the main LEP waves (N1, N2, and P2). Here, in three experiments, we identified a set of rules that the human nervous system obeys to identify changes in the spatial location of a nociceptive stimulus. We showed that the N2 wave is sensitive to: (1) large displacements between consecutive stimuli in egocentric, but not somatotopic coordinates; and (2) displacements that entail a behaviorally relevant change in the stimulus location. These findings indicate that nociceptive-evoked vertex potentials are sensitive to behaviorally relevant changes in the location of a nociceptive stimulus with respect to the body, and that the hand is a particularly behaviorally important site
Comparison between the lattice dynamics and molecular dynamics methods: Calculation results for MgSiO3 perovskite
The lattice dynamics (LD) and molecular dynamics (MD) methods have been used to calculate the structure, bulk modulus, and volume thermal expansivity of MgSiO3 perovskite, in order to investigate the reliability of the two simulation techniques over a wide range of temperature and pressure conditions. At an intermediate temperature of 500 K and zero pressure, the LD and MD values are in exellent agreement for both the structure and bulk modulus of MgSiO3 perovskite. At high temperatures and zero pressure, however, the LD method, which is based on the quasi-harmonic approximation, increasingly overestimates the molar volume of MgSiO3 perovskite because of the neglect of higher-order anharmonic terms. At the high temperatures and high pressures prevailing in the lower mantle, the errors in the LD values for both the molar volume and bulk modulus, relative to the MD values, are generally small or negligible. However, since anharmonicity decreases substantially with pressure but increases rapidly with temperature, the error in the LD simulated volume thermal expansivity is serious, especially in the lower pressure region
The interferon-stimulated gene IFITM3 restricts West Nile virus infection and pathogenesis
The interferon-induced transmembrane protein (IFITM) family of proteins inhibit infection of several different enveloped viruses in cell culture by virtue of their ability to restrict entry and fusion from late endosomes. As few studies have evaluated the importance of Ifitm3 in vivo in restricting viral pathogenesis, we investigated its significance as an antiviral gene against West Nile virus (WNV), an encephalitic flavivirus, in cells and mice. Ifitm3(−/−) mice were more vulnerable to lethal WNV infection, and this was associated with greater virus accumulation in peripheral organs and central nervous system tissues. As no difference in viral burden in the brain or spinal cord was observed after direct intracranial inoculation, Ifitm3 likely functions as an antiviral protein in nonneuronal cells. Consistent with this, Ifitm3(−/−) fibroblasts but not dendritic cells resulted in higher yields of WNV in multistep growth analyses. Moreover, transcomplementation experiments showed that Ifitm3 inhibited WNV infection independently of Ifitm1, Ifitm2, Ifitm5, and Ifitm6. Beyond a direct effect on viral infection in cells, analysis of the immune response in WNV-infected Ifitm3(−/−) mice showed decreases in the total number of B cells, CD4(+) T cells, and antigen-specific CD8(+) T cells. Finally, bone marrow chimera experiments demonstrated that Ifitm3 functioned in both radioresistant and radiosensitive cells, as higher levels of WNV were observed in the brain only when Ifitm3 was absent from both compartments. Our analyses suggest that Ifitm3 restricts WNV pathogenesis likely through multiple mechanisms, including the direct control of infection in subsets of cells. IMPORTANCE As part of the mammalian host response to viral infections, hundreds of interferon-stimulated genes (ISGs) are induced. The inhibitory activity of individual ISGs varies depending on the specific cell type and viral pathogen. Among ISGs, the genes encoding interferon-induced transmembrane protein (IFITM) have been reported to inhibit multiple families of viruses in cell culture. However, few reports have evaluated the impact of IFITM genes on viral pathogenesis in vivo. In this study, we characterized the antiviral activity of Ifitm3 against West Nile virus (WNV), an encephalitic flavivirus, using mice with a targeted gene deletion of Ifitm3. Based on extensive virological and immunological analyses, we determined that Ifitm3 protects mice from WNV-induced mortality by restricting virus accumulation in peripheral organs and, subsequently, in central nervous system tissues. Our data suggest that Ifitm3 restricts WNV pathogenesis by multiple mechanisms and functions in part by controlling infection in different cell types
Depressive symptoms and obesity: instrumental variable analysis using mother–offspring pairs in the 1970 British Cohort Study
Background: The extent to which depression and obesity are causally related remains to be determined. We used intergenerational data on mother–offspring pairs in an instrumental variable analysis to examine the longitudinal association between adolescent depressive symptoms and body mass index (BMI) in adulthood.
Methods: A total of 4733 mother–offspring pairs were identified from the 1970 British Cohort Study. Mothers completed the Malaise Inventory to assess depressive symptoms on three occasions across their offsprings' childhood/adolescence (aged 5, 10 and 16 years). Height and weight were recorded in mother and offspring (aged 16 years). Measures of height, weight and the Malaise Inventory were repeated in the participant at the age of 42 years.
Results: Maternal malaise score was associated with offspring malaise score, thus confirming the validity of the chosen instrumental variable. A higher mother’s malaise score was associated with higher offspring BMI at follow-up (B=0.043; 95% confidence interval (CI): 0.013, 0.072). There was a higher risk of adulthood offspring obesity in mothers with two or three episodes of depression compared with one or none (odds ratio, 1.42; 95% CI: 1.14, 1.76). The maternal malaise–offspring BMI association remained (P=0.003) after adjustment for offspring malaise score, suggesting that maternal mental health influences offspring obesity through mechanisms other than depression. Results from standard and instrumental variable analyses did not support a causal pathway in a direction from BMI to depression.
Conclusions: Our data support a causal pathway linking adolescent depressive symptoms to adiposity in adulthood over 26 years follow-up. The reverse direction, that is, adiposity to depression, was not supported
Role of the mesoamygdaloid dopamine projection in emotional learning
Amygdala dopamine is crucially involved in the acquisition of Pavlovian associations, as measured via conditioned approach to the location of the unconditioned stimulus (US). However, learning begins before skeletomotor output, so this study assessed whether amygdala dopamine is also involved in earlier 'emotional' learning. A variant of the conditioned reinforcement (CR) procedure was validated where training was restricted to curtail the development of selective conditioned approach to the US location, and effects of amygdala dopamine manipulations before training or later CR testing assessed. Experiment 1a presented a light paired (CS+ group) or unpaired (CS- group) with a US. There were 1, 2 or 10 sessions, 4 trials per session. Then, the US was removed, and two novel levers presented. One lever (CR+) presented the light, and lever pressing was recorded. Experiment 1b also included a tone stimulus. Experiment 2 applied intra-amygdala R(+) 7-OH-DPAT (10 nmol/1.0 A mu l/side) before two training sessions (Experiment 2a) or a CR session (Experiment 2b). For Experiments 1a and 1b, the CS+ group preferred the CR+ lever across all sessions. Conditioned alcove approach during 1 or 2 training sessions or associated CR tests was low and nonspecific. In Experiment 2a, R(+) 7-OH-DPAT before training greatly diminished lever pressing during a subsequent CR test, preferentially on the CR+ lever. For Experiment 2b, R(+) 7-OH-DPAT infusions before the CR test also reduced lever pressing. Manipulations of amygdala dopamine impact the earliest stage of learning in which emotional reactions may be most prevalent
Class II Phosphoinositide 3-Kinases Contribute to Endothelial Cells Morphogenesis
PMCID: PMC3539993This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Fusion of Range and Stereo Data for High-Resolution Scene-Modeling
This work has received funding from Agence Nationale de la Recherche under the MIXCAM project number ANR-13-BS02-0010-01. Georgios Evangelidis is the corresponding author
Climate tolerances and trait choices shape continental patterns of urban tree biodiversity
Aim: We propose and test a climate tolerance and trait choice hypothesis of urban macroecological variation in which strong filtering associated with low winter temperatures restricts urban biodiversity while weak filtering associated with warmer temperatures and irrigation allows dispersal of species from a global source pool, thereby increasing urban biodiversity. Location: Twenty cities across the USA and Canada. Methods: We examined variation in tree community taxonomic diversity, origins and production of an aesthetic ecosystem service trait in a cross-section of urban field surveys. We correlated urban tree community composition indicators with a key climate restriction, namely mean minimum winter temperature, and evaluated alternative possible drivers: precipitation, summer maximum temperature, population size and the percentage of adults with a college education. Results: Species accumulation curves differed substantially among cities, with observed richness varying from 22 to 122 species. Similarities in tree communities decreased exponentially with increases in climatic differences. Ordination of tree communities showed strong separation among cities with component axes correlated with minimum winter temperature and annual precipitation. Variation among urban tree communities in richness, origins and the provisioning of an aesthetic ecosystem service were all correlated with minimum winter temperature. Main conclusions: The urban climate tolerance and trait choice hypothesis provides a coherent mechanism to explain the large variation among urban tree communities resulting from an interacting environment, species and human decisions. Reconciling the feedbacks between human decision making and biophysical limitations provides a foundation for an urban ecological theory that can better understand and predict the dynamics of other linked biotic communities, associated ecosystem dynamics and resulting services provided to urban residents
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