821 research outputs found
Use of prescription drugs and future delinquency among adolescent offenders
Non-medical use of prescription drugs (NMUPD) by adolescents is a significant public health concern. The present study investigated the profile of NMUPD in 1349 adolescent offenders from the Pathways to Desistance project, and whether NMUPD predicted future delinquency using longitudinal data. Results indicated that increased frequency and recency of NMUPD in adolescent offenders are related to some demographic factors, as well as increased risk for violence exposure, mental health diagnoses, other drug use, and previous delinquency, suggesting that severity of NMUPD is important to consider. However, ANCOVA analyses found that NMUPD was not a significant predictor of drug-related, non-aggressive, or aggressive delinquency 12 months later beyond other known correlates of delinquency. Age, sex, exposure to violence, lower socioeconomic status, more alcohol use, and having delinquency histories were more important than NMUPD in predicting future delinquency. These findings suggest that although NMUPD is an important risk factor relating to many correlates of delinquency, it does not predict future delinquency beyond other known risk factors
Lifetimes of electrons in the Shockley surface state band of Ag(111)
We present a theoretical many-body analysis of the electron-electron (e-e)
inelastic damping rate of electron-like excitations in the Shockley
surface state band of Ag(111). It takes into account ab-initio band structures
for both bulk and surface states. is found to increase more rapidly as
a function of surface state energy E than previously reported, thus leading to
an improved agreement with experimental data
Interaction of the Electromagnetic p-Waves with Thin Metal Films
For the first time it is shown that for thin metallic films thickness of
which not exceed thickness of skin-layer, the problem allows analytical
solution for arbitrary boundary value problems. The analysis of dependence of
coefficients of transmission, reflection and absorbtion on angle incidence,
thickness of films and coefficient of specular reflection is carried out.Comment: 15 pages, 9 figure
Interaction of Electromagnetic S-Wave with a Metal Film Located Between Two Dielectric Mediums
Generalization of the theory of interaction of electromagnetic S-wave with a
metal film on a case of the film concluded between two dielectric environments
is developed.Comment: 13 pages, 10 figure
Electromagnetic field correlations near a surface with a nonlocal optical response
The coherence length of the thermal electromagnetic field near a planar
surface has a minimum value related to the nonlocal dielectric response of the
material. We perform two model calculations of the electric energy density and
the field's degree of spatial coherence. Above a polar crystal, the lattice
constant gives the minimum coherence length. It also gives the upper limit to
the near field energy density, cutting off its divergence. Near an
electron plasma described by the semiclassical Lindhard dielectric function,
the corresponding length scale is fixed by plasma screening to the Thomas-Fermi
length. The electron mean free path, however, sets a larger scale where
significant deviations from the local description are visible.Comment: 15 pages, 7 figure files (.eps), \documentclass[global]{svjour},
accepted in special issue "Optics on the Nanoscale" (Applied Physics B, eds.
V. Shalaev and F. Tr\"ager
Metabolic effects of elevated temperature on organic acid degradation in ripening <em>Vitis vinifera</em> fruit
First published online: September 1, 2014Berries of the cultivated grapevine Vitis vinifera are notably responsive to temperature, which can influence fruit quality and hence the future compatibility of varieties with their current growing regions. Organic acids represent a key component of fruit organoleptic quality and their content is significantly influenced by temperature. The objectives of this study were to (i) manipulate thermal regimes to realistically capture warming-driven reduction of malate content in Shiraz berries, and (ii) investigate the mechanisms behind temperature-sensitive malate loss and the potential downstream effects on berry metabolism. In the field we compared untreated controls at ambient temperature with longer and milder warming (2-4 °C differential for three weeks; Experiment 1) or shorter and more severe warming (4-6 °C differential for 11 days; Experiment 2). We complemented field trials with control (25/15 °C) and elevated (35/20 °C) day/night temperature controlled-environment trials using potted vines (Experiment 3). Elevating maximum temperatures (4-10 °C above controls) during pre-véraison stages led to higher malate content, particularly with warmer nights. Heating at véraison and ripening stages reduced malate content, consistent with effects typically seen in warm vintages. However, when minimum temperatures were also raised by 4-6 °C, malate content was not reduced, suggesting that the regulation of malate metabolism differs during the day and night. Increased NAD-dependent malic enzyme activity and decreased phosphoenolpyruvate carboxylase and pyruvate kinase activities, as well as the accumulation of various amino acids and γ-aminobutyric acid, suggest enhanced anaplerotic capacity of the TCA cycle and a need for coping with decreased cytosolic pH in heated fruit.C. Sweetman, V. O. Sadras, R. D. Hancock, K. L. Soole and C. M. For
Quantum Phase Extraction in Isospectral Electronic Nanostructures
Quantum phase is not a direct observable and is usually determined by
interferometric methods. We present a method to map complete electron wave
functions, including internal quantum phase information, from measured
single-state probability densities. We harness the mathematical discovery of
drum-like manifolds bearing different shapes but identical resonances, and
construct quantum isospectral nanostructures possessing matching electronic
structure but divergent physical structure. Quantum measurement (scanning
tunneling microscopy) of these "quantum drums" [degenerate two-dimensional
electron states on the Cu(111) surface confined by individually positioned CO
molecules] reveals that isospectrality provides an extra topological degree of
freedom enabling robust quantum state transplantation and phase extraction.Comment: Published 8 February 2008 in Science; 13 page manuscript (including 4
figures) + 13 page supplement (including 6 figures); supplementary movies
available at http://mota.stanford.ed
Simultaneous non-negative matrix factorization for multiple large scale gene expression datasets in toxicology
Non-negative matrix factorization is a useful tool for reducing the dimension of large datasets. This work considers simultaneous non-negative matrix factorization of multiple sources of data. In particular, we perform the first study that involves more than two datasets. We discuss the algorithmic issues required to convert the approach into a practical computational tool and apply the technique to new gene expression data quantifying the molecular changes in four tissue types due to different dosages of an experimental panPPAR agonist in mouse. This study is of interest in toxicology because, whilst PPARs form potential therapeutic targets for diabetes, it is known that they can induce serious side-effects. Our results show that the practical simultaneous non-negative matrix factorization developed here can add value to the data analysis. In particular, we find that factorizing the data as a single object allows us to distinguish between the four tissue types, but does not correctly reproduce the known dosage level groups. Applying our new approach, which treats the four tissue types as providing distinct, but related, datasets, we find that the dosage level groups are respected. The new algorithm then provides separate gene list orderings that can be studied for each tissue type, and compared with the ordering arising from the single factorization. We find that many of our conclusions can be corroborated with known biological behaviour, and others offer new insights into the toxicological effects. Overall, the algorithm shows promise for early detection of toxicity in the drug discovery process
Nuclear receptors in vascular biology
Nuclear receptors sense a wide range of steroids and hormones (estrogens, progesterone, androgens, glucocorticoid, and mineralocorticoid), vitamins (A and D), lipid metabolites, carbohydrates, and xenobiotics. In response to these diverse but critically important mediators, nuclear receptors regulate the homeostatic control of lipids, carbohydrate, cholesterol, and xenobiotic drug metabolism, inflammation, cell differentiation and development, including vascular development. The nuclear receptor family is one of the most important groups of signaling molecules in the body and as such represent some of the most important established and emerging clinical and therapeutic targets. This review will highlight some of the recent trends in nuclear receptor biology related to vascular biology
Second primary malignancies in patients with male breast cancer
An international multicentre study of first and second primary neoplasms associated with male breast cancer was carried out by pooling data from 13 cancer registries. Among a total of 3409 men with primary breast cancer, 426 (12.5%) developed a second neoplasia; other than breast cancer, a 34% overall excess risk of second primary neoplasia, affecting the small intestine (standardised incidence ratio, 4.95, 95% confidence interval, 1.35–12.7), rectum (1.78, 1.20–2.54), pancreas (1.93, 1.14–3.05), skin (nonmelanoma, 1.65, 1.16–2.29), prostate (1.61, 1.34–1.93) and lymphohaematopoietic system (1.63, 1.12–2.29). A total of 225 male breast cancers was recorded after cancers other than breast cancer, but an increase was found only after lymphohaematopoietic neoplasms. BRCA2 (and to some extent BRCA1) mutations may explain the findings for pancreatic and prostate cancers. Increases at other sites may be related to unknown factors or to chance. This large study shows that the risks for second discordant tumours after male breast cancer pose only a moderate excess risk
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