Structural and dielectric properties of Sr2_{2}TiO4_{4} from first principles

We have investigated the structural and dielectric properties of Sr$_{2}$TiO$_{4}$,the first member of the Sr$_{n+1}$Ti$_{n}$O$_{3n+1}$ Ruddlesden-Popper series, within density functional theory. Motivated by recent work in which thin films of Sr$_{2}$TiO$_{4}$ were grown by molecular beam epitaxy (MBE) on SrTiO$_{3}$ substrates, the in-plane lattice parameter was fixed to the theoretically optimized lattice constant of cubic SrTiO$_{3}$ (n=$\infty$), while the out-of-plane lattice parameter and the internal structural parameters were relaxed. The fully relaxed structure was also investigated. Density functional perturbation theory was used to calculate the zone-center phonon frequencies, Born effective charges, and the electronic dielectric permittivity tensor. A detailed study of the contribution of individual infrared-active modes to the static dielectric permittivity tensor was performed. The calculated Raman and infrared phonon frequencies were found to be in agreement with experiment where available. Comparisons of the calculated static dielectric permittivity with experiments on both ceramic powders and epitaxial thin films are discussed.Comment: 11 pages, 1 figure, 8 tables, submitted to Phys. Rev.

Increasing Short-Stay Unplanned Hospital Admissions among Children in England; Time Trends Analysis '97-'06

BACKGROUND: Timely care by general practitioners in the community keeps children out of hospital and provides better continuity of care. Yet in the UK, access to primary care has diminished since 2004 when changes in general practitioners' contracts enabled them to 'opt out' of providing out-of-hours care and since then unplanned pediatric hospital admission rates have escalated, particularly through emergency departments. We hypothesised that any increase in isolated short stay admissions for childhood illness might reflect failure to manage these cases in the community over a 10 year period spanning these changes. METHODS AND FINDINGS: We conducted a population based time trends study of major causes of hospital admission in children 2 days. By 2006, 67.3% of all unplanned admissions were isolated short stays <2 days. The increases in admission rates were greater for common non-infectious than infectious causes of admissions. CONCLUSIONS: Short stay unplanned hospital admission rates in young children in England have increased substantially in recent years and are not accounted for by reductions in length of in-hospital stay. The majority are isolated short stay admissions for minor illness episodes that could be better managed by primary care in the community and may be evidence of a failure of primary care services

Guidelines for the recording and evaluation of pharmaco-EEG data in man: the International Pharmaco-EEG Society (IPEG)

The International Pharmaco-EEG Society (IPEG) presents updated guidelines summarising the requirements for the recording and computerised evaluation of pharmaco-EEG data in man. Since the publication of the first pharmaco-EEG guidelines in 1982, technical and data processing methods have advanced steadily, thus enhancing data quality and expanding the palette of tools available to investigate the action of drugs on the central nervous system (CNS), determine the pharmacokinetic and pharmacodynamic properties of novel therapeutics and evaluate the CNS penetration or toxicity of compounds. However, a review of the literature reveals inconsistent operating procedures from one study to another. While this fact does not invalidate results per se, the lack of standardisation constitutes a regrettable shortcoming, especially in the context of drug development programmes. Moreover, this shortcoming hampers reliable comparisons between outcomes of studies from different laboratories and hence also prevents pooling of data which is a requirement for sufficiently powering the validation of novel analytical algorithms and EEG-based biomarkers. The present updated guidelines reflect the consensus of a global panel of EEG experts and are intended to assist investigators using pharmaco-EEG in clinical research, by providing clear and concise recommendations and thereby enabling standardisation of methodology and facilitating comparability of data across laboratories

Properties of B-Mesons in Lattice QCD

The results of an extensive study of B-meson properties in quenched lattice QCD are presented. The studies are carried out in the static quark limit where the b-quark is taken to be infinitely massive. Our computations rely on a multistate smearing method introduced previously, with smearing functions generated from a relativistic lattice quark model. Systematic errors arising from excited state contamination, finite volume effects, and the chiral extrapolation for the light quarks are estimated. We obtain continuum results for the mass splitting M_{B_s}- M_{B_u} = 86 (+/-)12(stat) {+7/-9}(syst) MeV, the ratio of decay constants f_{B_s}/f_{B_u} = 1.22 (+/-)0.04(stat) (+/-)0.02 (syst). For the B-meson decay constant we separately exhibit the sizable uncertainties in the extrapolation to the continuum limit a -> 0 and higher order perturbative matching. We obtain f_{B} = 188 (+/-)23(stat) (+/-)15(syst) {+26/-0}(extrap) (+/-)14 (pert) MeV. ----- [Postscript version of paper available by anonymous ftp at fncrd6.fnal.gov. The file is fb.ps in subdirectory theory.]Comment: 75 pages, FERMILAB-PUB-94/164-

Color and stellar population gradients in galaxies. Correlation with mass

We analyze the color gradients (CGs) of ~50000 nearby SDSS galaxies. From synthetic spectral models based on a simplified star formation recipe, we derive the mean spectral properties, and explain the observed radial trends of the color as gradients of the stellar population age and metallicity (Z). The most massive ETGs (M_* > 10^{11} Msun) have shallow CGs in correspondence of shallow (negative) Z gradients. In the stellar mass range 10^(10.3-10.5) < M_* < 10^(11) Msun, the Z gradients reach their minimum of ~ -0.5 dex^{-1}. At M_* ~ 10^{10.3-10.5} Msun, color and Z gradient slopes suddenly change. They turn out to anti-correlate with the mass, becoming highly positive at the very low masses. We have also found that age gradients anti-correlate with Z gradients, as predicted by hierarchical cosmological simulations for ETGs. On the other side, LTGs have gradients which systematically decrease with mass (and are always more negative than in ETGs), consistently with the expectation from gas infall and SN feedback scenarios. Z is found to be the main driver of the trend of color gradients, especially for LTGs, but age gradients are not negligible and seem to play a significant role too. We have been able to highlight that older galaxies have systematically shallower age and Z gradients than younger ones. Our results for high-mass galaxies are in perfect agreement with predictions based on the merging scenario, while the evolution of LTGs and younger and less massive ETGs seems to be mainly driven by infall and SN feedback. (Abridged)Comment: 20 pages, 16 figures, accepted for publication on MNRAS. This version includes revisions after the referee's report

Revisiting Brown Versus Board of Education: Differences in School Context and the influence of Racial Attitudes on Academic Attainment and Civic Engagement among Black Americans across the Lifespan

Since Brown versus the Board of Education 60 years ago, educators and social and behavioral scientists have tried to identify factors related to better achievement for Black Americans. Since the desegregation of schools in the U.S., Black American students have reported lower grade point averages, standardized test scores, and graduation rates (Allen, 1992). Previous research has investigated school context and climate as well as the influence of racial attitudes on academic achievement. Findings suggest that positive student perceptions of school climate and context (e.g., pride, social support, relationships with a teacher, access to resources) were related to better academic outcomes (Hurley & Lustbader, 1997). However, the research on the influence of racial attitudes have been inconclusive (Chavous et al., 2003; Fordham & Ogbu 1986). Thus, the purpose of this study is two-fold. First, to explore whether racial attitudes were related to academic attainment and civic engagement, and second, to examine whether there are differences in perceptions in school pride and school climate for students in historically black high schools and historically white high schools. To assess the aforementioned research questions, thirty-three Black American high school graduates from a historically white high school and eighty-two Black Americans from historically black high schools were sampled. Spearman Rho correlations and Independent sample T-tests were run to assess the relationship between the following. 1) Racial attitudes, educational attainment, and civic engagement. 2) Differences in perceptions of school climate for Blacks at historically White and Black high schools. Findings reveal statistically significant associations between racial attitudes and educational attainment as well as civic engagement. Moreover, differences were also found in perceptions of climate across school types. Given these results, further research is needed to explore the influence of students’ perception of their school experience and racial attitudes upon educational and life outcomes

Characterization of the rapid-onset type of behavioral sensitization to amphetamine in mice: Role of drug-environment conditioning

A rapid-onset type of behavioral sensitization (ROBS) has been demonstrated in rats treated with a single 'priming' injection of amphetamine (AMP). in that species, however, this phenomenon was restricted to AMP-induced stereotyped behavior (SB), not occurring for the locomotor-stimulant effect (LSE) of AMP and not reflecting environment-specific sensitization. in the present study, the ROBS was characterized in the mouse. Mice received a single 'priming' intraperitoneal injection of 5.0 mg/kg AMP which was paired or not with environment. At different intervals (3, 4 or 5 h) subgroups were tested for AMP (1.5 or 5.0 mg/kg)-induced SB or AMP (1.5 mg/kg)-induced open-field LSE. Results showed that: (1) in the absence of drug-environment association, a priming injection of AMP increased the SB induced by a 1.5 mg/kg AMP challenge injection given 3 h (but not 4 or 5 h) later; (2) when the dose of AMP challenge injection was increased to 5.0 mg/kg, an enhancement of SB was verified at all the intervals tested (3, 4, and 5 h); (3) when animals were tested in an open field, the priming injection of AMP produced an increase in the LSE of a 1.5 mg/kg AMP challenge injection, given 4 h later; (4) drug-environment association increased both SB and locomotion after a saline challenge injection and potentiated the rapid-onset sensitization of both behaviors in AMP-challenged mice. Collectively, these results demonstrate that the ROBS phenomenon also occurs in mice, is extended to AMP-induced LSE, and is markedly potentiated by (but does not depend on) environmental conditioning.Universidade Federal de São Paulo, Escola Paulista Med, Dept Farmacol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Farmacol, BR-04023062 São Paulo, BrazilWeb of Scienc

Formation of a morphine-conditioned place preference does not change the size of evoked potentials in the ventral hippocampus–nucleus accumbens projection

Abstract In opioid addiction, cues and contexts associated with drug reward can be powerful triggers for drug craving and relapse. The synapses linking ventral hippocampal outputs to medium spiny neurons of the accumbens may be key sites for the formation and storage of associations between place or context and reward, both drug-related and natural. To assess this, we implanted rats with electrodes in the accumbens shell to record synaptic potentials evoked by electrical stimulation of the ventral hippocampus, as well as continuous local-field-potential activity. Rats then underwent morphine-induced (10 mg/kg) conditioned-place-preference training, followed by extinction. Morphine caused an acute increase in the slope and amplitude of accumbens evoked responses, but no long-term changes were evident after conditioning or extinction of the place preference, suggesting that the formation of this type of memory does not lead to a net change in synaptic strength in the ventral hippocampal output to the accumbens. However, analysis of the local field potential revealed a marked sensitization of theta- and high-gamma-frequency activity with repeated morphine administration. This phenomenon may be linked to the behavioral changes—such as psychomotor sensitization and the development of drug craving—that are associated with chronic use of addictive drugs

Comprehensive and Integrated Genomic Characterization of Adult Soft Tissue Sarcomas

Summary Sarcomas are a broad family of mesenchymal malignancies exhibiting remarkable histologic diversity. We describe the multi-platform molecular landscape of 206 adult soft tissue sarcomas representing 6 major types. Along with novel insights into the biology of individual sarcoma types, we report three overarching findings: (1) unlike most epithelial malignancies, these sarcomas (excepting synovial sarcoma) are characterized predominantly by copy-number changes, with low mutational loads and only a few genes (TP53, ATRX, RB1) highly recurrently mutated across sarcoma types; (2) within sarcoma types, genomic and regulomic diversity of driver pathways defines molecular subtypes associated with patient outcome; and (3) the immune microenvironment, inferred from DNA methylation and mRNA profiles, associates with outcome and may inform clinical trials of immune checkpoint inhibitors. Overall, this large-scale analysis reveals previously unappreciated sarcoma-type-specific changes in copy number, methylation, RNA, and protein, providing insights into refining sarcoma therapy and relationships to other cancer types

Integrated genomic characterization of oesophageal carcinoma

Oesophageal cancers are prominent worldwide; however, there are few targeted therapies and survival rates for these cancers remain dismal. Here we performed a comprehensive molecular analysis of 164 carcinomas of the oesophagus derived from Western and Eastern populations. Beyond known histopathological and epidemiologic distinctions, molecular features differentiated oesophageal squamous cell carcinomas from oesophageal adenocarcinomas. Oesophageal squamous cell carcinomas resembled squamous carcinomas of other organs more than they did oesophageal adenocarcinomas. Our analyses identified three molecular subclasses of oesophageal squamous cell carcinomas, but none showed evidence for an aetiological role of human papillomavirus. Squamous cell carcinomas showed frequent genomic amplifications of CCND1 and SOX2 and/or TP63, whereas ERBB2, VEGFA and GATA4 and GATA6 were more commonly amplified in adenocarcinomas. Oesophageal adenocarcinomas strongly resembled the chromosomally unstable variant of gastric adenocarcinoma, suggesting that these cancers could be considered a single disease entity. However, some molecular features, including DNA hypermethylation, occurred disproportionally in oesophageal adenocarcinomas. These data provide a framework to facilitate more rational categorization of these tumours and a foundation for new therapies.ope