735 research outputs found
Repulsive Casimir force between silicon dioxide and superconductor
We have presented a detailed investigation of the Casimir interaction between
the superconductor Bi2Sr2CaCu2O8+{\delta} (BSCCO) and silicon dioxide with the
presence of bromobenzene in between. We found the dispersion force is repulsive
and the magnitude of the force can be changed by varying the thickness of
object and temperature. The repulsive force would provide a method to deal with
the stiction problems and bring much meaningful from practical views.Comment: 3 pages, 2 figure
Berry phase and quantum criticality in Yang--Baxter systems
Spin interaction Hamiltonians are obtained from the unitary Yang--Baxter
-matrix. Based on which, we study Berry phase and quantum
criticality in the Yang--Baxter systems.Comment: 7 pages, no figures. Accepted for publication in Annals of Physic
A new multi-center approach to the exchange-correlation interactions in ab initio tight-binding methods
A new approximate method to calculate exchange-correlation contributions in
the framework of first-principles tight-binding molecular dynamics methods has
been developed. In the proposed scheme on-site (off-site) exchange-correlation
matrix elements are expressed as a one-center (two-center) term plus a {\it
correction} due to the rest of the atoms. The one-center (two-center) term is
evaluated directly, while the {\it correction} is calculated using a variation
of the Sankey-Niklewski \cite{Sankey89} approach generalized for arbitrary
atomic-like basis sets. The proposed scheme for exchange-correlation part
permits the accurate and computationally efficient calculation of corresponding
tight-binding matrices and atomic forces for complex systems. We calculate bulk
properties of selected transition (W,Pd), noble (Au) or simple (Al) metals, a
semiconductor (Si) and the transition metal oxide Ti with the new method
to demonstrate its flexibility and good accuracy.Comment: 17 pages, 5 figure
Adherence to Mediterranean Diet Pattern among Spanish Adults Attending a Medical Centre: Nondiabetic Subjects and Type 1 and 2 Diabetic Patients.
Objective. To identify adherence to Mediterranean diet among two groups of Spanish adults: diabetic patients and nondiabetic subjects. Methods. Adherence to Mediterranean diet was measured by a 14-item screener (scale: 0–14; =5: low, 6–9: moderate, and =10: high) in 351 volunteers. Results. Mean age was 50.97±12.58 in nondiabetics (n=154) and 59.50±13.34 in diabetics (n = 197). The whole sample scored 8.77 ± 1.82. Score was 9.19 ± 1.84 in nondiabetic females (n = 58) and 8.15 ± 1.79 in diabetic females (n = 85) (p = 0 003), due to lower consumption of olive oil (p = 0 005) and nuts (p = 0 000). Type 2 diabetic males (n = 79; 8.76 ± 1.88) consumed less olive oil than healthy males (n = 28; 9.36 ± 1.59) (p = 0 046). Up to 30-year-old nondiabetics scored lower than more than 60-year-old nondiabetics (8.40 ± 1.5 versus 9.74 ± 2.03; p = 0 047). The youngest ate less olive oil (p = 0 002) and more pastries (p = 0 007). Conclusions. The sample presented moderate adherence to Mediterranean diet in all subgroups. Scientific evidence about the benefits of Mediterranean diet, olive oil, and nuts supports the recommendation to increase consumption of olive oil and nuts in diabetic women and of daily olive oil in type 2 diabetic men, reducing consumption of red meat, butter, and pastries, and to promote Mediterranean diet among the youngest of the sample studie
Entanglement entropy in quantum spin chains with finite range interaction
We study the entropy of entanglement of the ground state in a wide family of
one-dimensional quantum spin chains whose interaction is of finite range and
translation invariant. Such systems can be thought of as generalizations of the
XY model. The chain is divided in two parts: one containing the first
consecutive L spins; the second the remaining ones. In this setting the entropy
of entanglement is the von Neumann entropy of either part. At the core of our
computation is the explicit evaluation of the leading order term as L tends to
infinity of the determinant of a block-Toeplitz matrix whose symbol belongs to
a general class of 2 x 2 matrix functions. The asymptotics of such determinant
is computed in terms of multi-dimensional theta-functions associated to a
hyperelliptic curve of genus g >= 1, which enter into the solution of a
Riemann-Hilbert problem. Phase transitions for thes systems are characterized
by the branch points of the hyperelliptic curve approaching the unit circle. In
these circumstances the entropy diverges logarithmically. We also recover, as
particular cases, the formulae for the entropy discovered by Jin and Korepin
(2004) for the XX model and Its, Jin and Korepin (2005,2006) for the XY model.Comment: 75 pages, 10 figures. Revised version with minor correction
Método Fl-pmc (fourier Lapped - Perceptron Multicamadas) Para A Estimação De Qualidade De Voz
A Patente de invenção para a estimação da qualidade subjetiva dos sinais de voz é compreendida por: a) técnicas de processamento de sinais aplicadas ao alinhamento (1) e ajustes para igualar o nível de energia (2) dos sinais de voz; aplicação das transformadas FFT (3) e MLT (4) e adaptação dos padrões resultantes às características auditivas humanas, a fim de revelar as informações espectrais e perceptuais dos sinais de voz; extração da diferença entre as SNR segmentadas (5) entre os sinais de voz; extração da distância espectral perceptual (6), após a aplicação da FFT e da MLT; extração da distância cepstral perceptual (7), após a aplicação da FFT e da MLT; cálculo da medida objetiva MOQV1 (8) após a aplicação da FFT e da MLT e cálculo da medida objetiva MOQV2 (9) após a aplicação da FFT e da MLT; implementação da rede neural Perceptron multicamadas para o mapeamento multidimensional e não-linear dos dez parâmetros extraídos dos sinais de voz numa correspondente estimativa da qualidade subjetiva dos sinais de voz (MOS ou CMOS) ou por um código binário associado aos valores MOS e CMOS (10).BR0204932 (A)G10L19/02G10L7/06BR20020204932G10L19/02G10L7/0
Reduced Bone Mass and Muscle Strength in Male 5α-Reductase Type 1 Inactivated Mice
Androgens are important regulators of bone mass but the relative importance of testosterone (T) versus dihydrotestosterone (DHT) for the activation of the androgen receptor (AR) in bone is unknown. 5α-reductase is responsible for the irreversible conversion of T to the more potent AR activator DHT. There are two well established isoenzymes of 5α-reductase (type 1 and type 2), encoded by separate genes (Srd5a1 and Srd5a2). 5α-reductase type 2 is predominantly expressed in male reproductive tissues whereas 5α-reductase type 1 is highly expressed in liver and moderately expressed in several other tissues including bone. The aim of the present study was to investigate the role of 5α-reductase type 1 for bone mass using Srd5a1−/− mice. Four-month-old male Srd5a1−/− mice had reduced trabecular bone mineral density (−36%, p<0.05) and cortical bone mineral content (−15%, p<0.05) but unchanged serum androgen levels compared with wild type (WT) mice. The cortical bone dimensions were reduced in the male Srd5a1−/− mice as a result of a reduced cortical periosteal circumference compared with WT mice. T treatment increased the cortical periosteal circumference (p<0.05) in orchidectomized WT mice but not in orchidectomized Srd5a1−/− mice. Male Srd5a1−/− mice demonstrated a reduced forelimb muscle grip strength compared with WT mice (p<0.05). Female Srd5a1−/− mice had slightly increased cortical bone mass associated with elevated circulating levels of androgens. In conclusion, 5α-reductase type 1 inactivated male mice have reduced bone mass and forelimb muscle grip strength and we propose that these effects are due to lack of 5α-reductase type 1 expression in bone and muscle. In contrast, the increased cortical bone mass in female Srd5a1−/− mice, is an indirect effect mediated by elevated circulating androgen levels
Measurement of D-s(+) and D-s(*+) production in B meson decays and from continuum e(+)e(-) annihilation at √s=10.6 GeV
This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APSNew measurements of Ds+ and Ds*+ meson production rates from B decays and from qq̅ continuum events near the Υ(4S) resonance are presented. Using 20.8 fb-1 of data on the Υ(4S) resonance and 2.6 fb-1 off-resonance, we find the inclusive branching fractions B(B⃗Ds+X)=(10.93±0.19±0.58±2.73)% and B(B⃗Ds*+X)=(7.9±0.8±0.7±2.0)%, where the first error is statistical, the second is systematic, and the third is due to the Ds+→φπ+ branching fraction uncertainty. The production cross sections σ(e+e-→Ds+X)×B(Ds+→φπ+)=7.55±0.20±0.34pb and σ(e+e-→Ds*±X)×B(Ds+→φπ+)=5.8±0.7±0.5pb are measured at center-of-mass energies about 40 MeV below the Υ(4S) mass. The branching fractions ΣB(B⃗Ds(*)+D(*))=(5.07±0.14±0.30±1.27)% and ΣB(B⃗Ds*+D(*))=(4.1±0.2±0.4±1.0)% are determined from the Ds(*)+ momentum spectra. The mass difference m(Ds+)-m(D+)=98.4±0.1±0.3MeV/c2 is also measured.This work was supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the Swiss NSF, A. P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation
Functional molecules in mesothelial to mesenchymal transition revealed by transcriptome analyses
Peritoneal fibrosis is a common complication of abdominal and pelvic surgery, and can also be triggered by peritoneal dialysis, resulting in treatment failure. In these settings, fibrosis is driven by activated myofibroblasts that are considered to be partly derived by mesothelial‐to‐mesenchymal transition (MMT). We hypothesized that, if the molecular signature of MMT could be better defined, these insights could be exploited to block this pathological cellular transition. Rat peritoneal mesothelial cells were purified by the use of an antibody against HBME1, a protein present on mesothelial cell microvilli, and streptavidin nanobead technology. After exposure of sorted cells to a well‐known mediator of MMT, transforming growth factor (TGF)‐β1, RNA sequencing was undertaken to define the transcriptomes of mesothelial cells before and during early‐phase MMT. MMT was associated with dysregulation of transcripts encoding molecules involved in insulin‐like growth factor (IGF) and bone morphogenetic protein (BMP) signalling. The application of either recombinant BMP4 or IGF‐binding protein 4 (IGFBP4) ameliorated TGF‐β1‐induced MMT in culture, as judged from the retention of epithelial morphological and molecular phenotypes, and reduced migration. Furthermore, peritoneal tissue from peritoneal dialysis patients showed less prominent immunostaining than control tissue for IGFBP4 and BMP4 on the peritoneal surface. In a mouse model of TGF‐β1‐induced peritoneal thickening, BMP4 immunostaining on the peritoneal surface was attenuated as compared with healthy controls. Finally, genetic lineage tracing of mesothelial cells was used in mice with peritoneal injury. In this model, administration of BMP4 ameliorated the injury‐induced shape change and migration of mesothelial cells. Our findings demonstrate a distinctive MMT signature, and highlight the therapeutic potential for BMP4, and possibly IGFBP4, to reduce MMT
Water quality is a poor predictor of recreational hotspots in England
Maintaining and improving water quality is key to the protection and restoration of aquatic ecosystems, which provide important benefits to society. In Europe, the Water Framework Directive (WFD) defines water quality based on a set of biological, hydro-morphological and chemical targets, and aims to reach good quality conditions in all river bodies by the year 2027. While recently it has been argued that achieving these goals will deliver and enhance ecosystem services, in particular recreational services, there is little empirical evidence demonstrating so. Here we test the hypothesis that good water quality is associated with increased utilization of recreational services, combining four surveys covering walking, boating, fishing and swimming visits, together with water quality data for all water bodies in eight River Basin Districts (RBDs) in England. We compared the percentage of visits in areas of good water quality to a set of null models accounting for population density, income, age distribution, travel distance, public access, and substitutability. We expect such association to be positive, at least for fishing (which relies on fish stocks) and swimming (with direct contact to water). We also test if these services have stronger association with water quality relative to boating and walking alongside rivers, canals or lakeshores. In only two of eight RBDs (Northumbria and Anglian) were both criteria met (positive association, strongest for fishing and swimming) when comparing to at least one of the null models. This conclusion is robust to variations in dataset size. Our study suggests that achieving the WFD water quality goals may not enhance recreational ecosystem services, and calls for further empirical research on the connection between water quality and ecosystem services
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