Multiband and impurity effects in infrared and optical spectra of MgB2

A short review of the optical and far-infrared measurements on MgB$_{2}$ is given. Multiband and multigap effects are analyzed by comparing optical properties with other experiments and {\em ab initio} calculations. The covered topics are: the plasma frequency, electron-phonon interaction, impurity scattering, the effects of C and Al substitution, interband transitions and the far-infrared signatures of the superconducting gaps.Comment: For the Special Physica C Issue on MgB2 (2007), 11 pages, 12 figure

Influence of topography on tide propagation and amplification in semi-enclosed basins

An idealized model for tide propagation and amplification in semi-enclosed rectangular basins is presented, accounting for depth differences by a combination of longitudinal and lateral topographic steps. The basin geometry is formed by several adjacent compartments of identical width, each having either a uniform depth or two depths separated by a transverse topographic step. The problem is forced by an incoming Kelvin wave at the open end, while allowing waves to radiate outward. The solution in each compartment is written as the superposition of (semi)-analytical wave solutions in an infinite channel, individually satisfying the depth-averaged linear shallow water equations on the f plane, including bottom friction. A collocation technique is employed to satisfy continuity of elevation and flux across the longitudinal topographic steps between the compartments. The model results show that the tidal wave in shallow parts displays slower propagation, enhanced dissipation and amplified amplitudes. This reveals a resonance mechanism, occurring when\ud the length of the shallow end is roughly an odd multiple of the quarter Kelvin wavelength. Alternatively, for sufficiently wide basins, also Poincaré waves may become resonant. A transverse step implies different wavelengths of the incoming and reflected Kelvin wave, leading to increased amplitudes in shallow regions and a shift of amphidromic points in the direction of the deeper part. Including the shallow parts near the basin’s closed end (thus capturing the Kelvin resonance mechanism) is essential to reproduce semi-diurnal and diurnal\ud tide observations in the Gulf of California, the Adriatic Sea and the Persian Gulf

Inconsistent boundaries

Research on this paper was supported by a grant from the Marsden Fund, Royal Society of New Zealand.Mereotopology is a theory of connected parts. The existence of boundaries, as parts of everyday objects, is basic to any such theory; but in classical mereotopology, there is a problem: if boundaries exist, then either distinct entities cannot be in contact, or else space is not topologically connected (Varzi in Noûs 31:26–58, 1997). In this paper we urge that this problem can be met with a paraconsistent mereotopology, and sketch the details of one such approach. The resulting theory focuses attention on the role of empty parts, in delivering a balanced and bounded metaphysics of naive space.PostprintPeer reviewe

"Homework feedback is...": Elementary and middle school teachers' conceptions of homework feedback

This study explored mathematics teachers' conceptions of the homework feedback focusing on four key aspects: definition, purpose, types, and perceived impact. Forty-seven teachers from elementary and middle schools participated in six focus groups. Data were analyzed using content analysis. To enhance the trustworthiness of findings, classroom observations were used for triangulation of data. Participants conceptualized homework feedback in three directions (i.e., teachers' feedback provided to students, students' feedback provided to teachers, and homework self-feedback), being teachers' monitoring of students' learning the purpose reported by most teachers. Participants also reported the types of homework feedback more frequently used in class (e.g., checking homework completion, checking homework on the board), and their perceived impact on students. Findings provide valuable information to deepen the understanding of the homework feedback process, which may help develop new avenues for future research.This study was conducted at Psychology Research Centre (UID/PSI/01662/2013), University of Minho, and supported by the Portuguese Foundation for Science and Technology and the Portuguese Ministry of Science, Technology and Higher Education through national funds and co-financed by FEDER through COMPETE2020 under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007653). JC was supported by a Ph.D. fellowship from the Portuguese Foundation for Science and Technology (FCT - SFRH/BD/95341/2013).info:eu-repo/semantics/publishedVersio

HIV-1 Vpr-Induced Apoptosis Is Cell Cycle Dependent and Requires Bax but Not ANT

The HIV-1 accessory protein viral protein R (Vpr) causes G(2) arrest and apoptosis in infected cells. We previously identified the DNA damage–signaling protein ATR as the cellular factor that mediates Vpr-induced G(2) arrest and apoptosis. Here, we examine the mechanism of induction of apoptosis by Vpr and how it relates to induction of G(2) arrest. We find that entry into G(2) is a requirement for Vpr to induce apoptosis. We investigated the role of the mitochondrial permeability transition pore by knockdown of its essential component, the adenine nucleotide translocator. We found that Vpr-induced apoptosis was unaffected by knockdown of ANT. Instead, apoptosis is triggered through a different mitochondrial pore protein, Bax. In support of the idea that checkpoint activation and apoptosis induction are functionally linked, we show that Bax activation by Vpr was ablated when ATR or GADD45α was knocked down. Certain mutants of Vpr, such as R77Q and I74A, identified in long-term nonprogressors, have been proposed to inefficiently induce apoptosis while activating the G(2) checkpoint in a normal manner. We tested the in vitro phenotypes of these mutants and found that their abilities to induce apoptosis and G(2) arrest are indistinguishable from those of HIV-1(NL4–3) vpr, providing additional support to the idea that G(2) arrest and apoptosis induction are mechanistically linked

CEO international experience and foreign IPOs

International audienceThis paper examines listing location as a managerial decision by using a sample of IPOs of Chinese entrepreneurial firms in mainland China, the United States and Hong Kong. We find that Chinese entrepreneurial firms managed by CEOs with international experience are more likely to undertake foreign IPOs, especially those returned from countries with more advanced legal institutions and those operating in high-tech industries. The credibility crisis for Chinese firms in 2010 switched the focus of foreign IPOs from the US to Hong Kong. These results are consistent across returnee CFOs and other senior executives with international experience

Underweight is independently associated with mortality in post-operative and non-operative patients admitted to the intensive care unit: a retrospective study

BACKGROUND: Low and high body mass index (BMI) have been recently shown to be associated with increased and decreased mortality after ICU admission, respectively. The objective of this study was to determine the impact of BMI on mortality and length of stay in patients admitted to the intensive care unit (ICU). METHODS: In this retrospective cohort study, the Acute Physiology and Chronic Health Evaluation (APACHE) III database of patients admitted to the ICUs of a tertiary academic medical center, from January 1997 to September 2002, was crossed with a Hospital Rule-based Systems database to obtain the height and weight of the patients on admission to the ICU. The cohort was divided in post-operative and non-operative groups. We created the following five subgroups based on the BMI: <18.5, 18.5 to 24.9, 25 to 29.9, 30.0 to 39.9, ≥ 40.0 Kg/m(2). A multiple logistic regression analysis was used to determine the independent impact of BMI on hospital mortality. The ICU length of stay ratio was defined as the ratio of the observed to the predicted LOS. P-value < 0.05 was considered significant. The 95% confidence interval (CI) was calculated for the odds ratio (OR). RESULTS: BMI was available in 19,669 of the 21,790 patients in the APACHE III database; 11,215 (57%) of the patients were admitted post-operatively. BMI < 18.5 was associated with increased mortality in both post-operative (OR = 2.14, 95% CI, 1.39 to 3.28) and non-operative (OR = 1.51, 95% CI, 1.13 to 2.01) patients. Post-operative patients with a BMI between 30.0 to 39.9 had a lower mortality rate (OR = 0.68, 95% CI, 0.49 to 0.94). Post-operative patients with BMI <18.5 or BMI ≥ 40 had an ICU length of stay ratio significantly higher than patients with BMI between 18.5 to 24.9. The addition of BMI < 18.5 did not improve significantly the accuracy of our prognostic model in predicting hospital mortality. CONCLUSIONS: Low BMI is associated with higher mortality in both post- and non-operative patients admitted to the ICU. LOS is increased in post-operative patients with low and high BMIs

Propensity score matching in estimating the effect of managerial education on academic planning behavior. Study design: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>In many academic settings teaching a particular topic is applied to every student enrolled in the same academic year, it is a difficult task for researchers to design a randomized control group study. This research aimed to estimate the effect of teaching management and planning on increasing academic planning behavior (APB), using propensity score matching (PSM).</p> <p>Methods</p> <p>In a cross-sectional survey utilizing a self-reported structured questionnaire on a systematic random sample of 421 students in Hanoi Medical University, one of the eight medical schools in Vietnam, this evaluation study adopted regression procedures to assess model fit, then PSM to create a matched control group in order to allow for evaluating the effect of management education.</p> <p>Results</p> <p>The study showed both direct and indirect effects of the education on behavior. After PSM to adjust for the possible confounders to balance statistically two groups - with and without management education, there is statistically a significant difference in APB between these two groups, making a net difference of 18.60% (p < .05). The estimated 18.6 percentage point increase can be translated into the practice of APB by 670 students in the population. This number of academic planners can be attributed to a high recall of important management and planning education.</p> <p>Conclusions</p> <p>The study provided theoretical as well as practical implications to guide the design of the education and evaluation of teaching.</p

Cag rnas induce dna damage and apoptosis by silencing nudt16 expression in polyglutamine degeneration

DNA damage plays a central role in the cellular pathogenesis of polyglutamine (polyQ) diseases, including Huntington's disease (HD). In this study, we showed that the expression of untranslatable expanded CAG RNA per se induced the cellular DNA damage response pathway. By means of RNA sequencing (RNA-seq), we found that expression of the Nudix hydrolase 16 (NUDT16) gene was down-regulated in mutant CAG RNA-expressing cells. The loss of NUDT16 function results in a misincorporation of damaging nucleotides into DNAs and leads to DNA damage. We showed that small CAG (sCAG) RNAs, species generated from expanded CAG transcripts, hybridize with CUG-containing NUDT16 mRNA and form a CAG-CUG RNA heteroduplex, resulting in gene silencing of NUDT16 and leading to the DNA damage and cellular apoptosis. These results were further validated using expanded CAG RNAexpressing mouse primary neurons and in vivo R6/2 HD transgenic mice. Moreover, we identified a bisamidinium compound, DB213, that interacts specifically with the major groove of the CAG RNA homoduplex and disfavors the CAG-CUG heteroduplex formation. This action subsequently mitigated RNA-induced silencing complex (RISC)-dependent NUDT16 silencing in both in vitro cell and in vivo mouse disease models. After DB213 treatment, DNA damage, apoptosis, and locomotor defects were rescued in HD mice. This work establishes NUDT16 deficiency by CAG repeat RNAs as a pathogenic mechanism of polyQ diseases and as a potential therapeutic direction for HD and other polyQ diseases