Terahertz photoconductivity and plasmon modes in double-quantum-well field-effect transistors

Double-quantum-well field-effect transistors with a grating gate exhibit a sharply resonant, voltage tuned terahertz photoconductivity. The voltage tuned resonance is determined by the plasma oscillations of the composite structure. The resonant photoconductivity requires a double-quantum well but the mechanism whereby plasma oscillations produce changes in device conductance is not understood. The phenomenon is potentially important for fast, tunable terahertz detectors

An analysis of precipitation isotope distributions across Namibia using historical data

Global precipitation isoscapes based on the Global Network for Isotopes in Precipitation (GNIP) network are an important toolset that aid our understanding of global hydrologiccycles. Although the GNIP database is instrumental in developing global isoscapes, data coverage in some regions of hydrological interest (e.g., drylands) is low or non-existent thus the accuracy and relevance of global isoscapes to these regions is debatable. Capitalizing on existing literature isotope data, we generated rainfall isoscapes for Namibia (dryland) using the cokriging method and compared it to a globally fitted isoscape (GFI) downscaled to country level. Results showed weak correlation between observed and predicted isotope values in the GFI model (r2 < 0.20) while the cokriging isoscape showed stronger correlation (r2 = 0.67). The general trend of the local cokriging isoscape is consistent with synoptic weather systems (i.e., influences from Atlantic Ocean maritime vapour, Indian Ocean maritime vapour, Zaire Air Boundary, the Intertropical Convergence Zone and Tropical Temperate Troughs) and topography affecting the region. However, because we used the unweighted approach in this method, due to data scarcity, the absolute values could beimproved in future studies. A comparison of local meteoric water lines (LMWL) constructed from the cokriging and GFI suggested that the GFI model still reflects the global averageeven when downscaled. The cokriging LMWL was however more consistent with expectations for an arid environment. The results indicate that although not ideal, for data deficientregions such as many drylands, the unweighted cokriging approach using historical local data can be an alternative approach to modelling rainfall isoscapes that are more relevantto the local conditions compared to using downscaled global isoscapes

An evaluation of |Vus| and precise tests of the Standard Model from world data on leptonic and semileptonic kaon decays

We present a global analysis of leptonic and semileptonic kaon decay data, including all recent results published by the BNL-E865, KLOE, KTeV, ISTRA+ and NA48 experiments. This analysis, in conjunction with precise lattice calculations of the hadronic matrix elements now available, leads to a very precise determination of |Vus| and allows us to perform several stringent tests of the Standard Model.Comment: LaTeX, 25 pages, 12 figures, 16 tables. Submitted to EPJC. v2: Minor changes for accepted version. No numerical results change

Precision tests of the Standard Model with leptonic and semileptonic kaon decays

We present a global analysis of leptonic and semileptonic kaon decays data, including all recent results by BNL-E865, KLOE, KTeV, ISTRA+, and NA48. Experimental results are critically reviewed and combined, taking into account theoretical (both analytical and numerical) constraints on the semileptonic kaon form factors. This analysis leads to a very accurate determination of Vus and allows us to perform several stringent tests of the Standard Model

Market structure, ESG performance, and corporate efficiency: Insights from Brazilian publicly traded companies

Using a sample of Brazilian listed companies, our study investigates the directional cause–effect relationship between market structure, ESG performance, and firm efficiency under a Stochastic Structural Relationship Programming (SSRP) model. Our empirical evidence is threefold. First, our findings indicate that firms with better environmental performance are more efficient, whereas lower ESG performance and poorer corporate governance practices are associated with a higher level of efficiency. Second, our study suggests that market structure measures (i.e., competition, concentration, and market power) have heterogeneous impacts on various ESG indexes. Specifically, higher market competition is associated with a lower concentration, better ESG performance and environmental performance, but worse corporate governance performance, although market power can only enhance the environmental and governance performance of firms. Third, the market structure proxies employed in this study are significantly attributed to firm efficiency. Our findings provide practical implications for various stakeholders and suggest avenues for future studies that can build on our evidence

Motif effects in Affymetrix GeneChips seriously affect probe intensities

An Affymetrix GeneChip consists of an array of hundreds of thousands of probes (each a sequence of 25 bases) with the probe values being used to infer the extent to which genes are expressed in the biological material under investigation. In this article, we demonstrate that these probe values are also strongly influenced by their precise base sequence. We use data from >28 000 CEL files relating to 10 different Affymetrix GeneChip platforms and involving nearly 1000 experiments. Our results confirm known effects (those due to the T7-primer and the formation of G-quadruplexes) but reveal other effects. We show that there can be huge variations from one experiment to another, and that there may also be sizeable disparities between batches within an experiment and between CEL files within a batch. © 2012 The Author(s)

Inactivation of Pseudomonas aeruginosa in mineral water by DP1 bacteriophage immobilized on ethylene-vinyl acetate copolymer used as seal caps of plastic bottles

Pseudomonas aeruginosa has been found in bottled natural mineral water, even though its presence is not allowed in this product by different food regulations. This study aimed to investigate the inactivation of P. aeruginosa present in mineral water by vB_PaeM_CEB_DP1 (short name DP1) bacteriophage immobilized on ethylenevinyl acetate (EVA) copolymer used as seal caps of plastic bottles. EVA was chemically modified using microwaveassisted alcoholysis, improving polymerphage binding. After that, DP1 phage was attached to EVA and EVAOH copolymers and both surfaces were tested for plaque formation using P. aeruginosa. Then, both materials containing immobilized phages were used as seal caps of plastic bottles and its antimicrobial capacity was tested against P. aeruginosa contaminating mineral water. The EVAOH resulted in higher hydrogen bond density that contributed significantly to the phage immobilization on the polymer surface. The polymers containing immobilized phages were able to reduce 0.53 log of P. aeruginosa population present inside mineral water bottles after 14days.The authors thank CAPES for scholarships to Cesar H. Wanke and Junia Novello. CNPq—National Council for Scientific and Technological Development, Brazil for financial support (grant numbers 308241/2015-0 and 306086/2018-2). Sanna Sillankorva acknowledges funding from the European Union’s Horizon 2020 research and innovation programme (grant number 713640).info:eu-repo/semantics/publishedVersio

Nonequilibrium Green's function theory for transport and gain properties of quantum cascade structures

The transport and gain properties of quantum cascade (QC) structures are investigated using a nonequilibrium Green's function (NGF) theory which includes quantum effects beyond a Boltzmann transport description. In the NGF theory, we include interface roughness, impurity, and electron-phonon scattering processes within a self-consistent Born approximation, and electron-electron scattering in a mean-field approximation. With this theory we obtain a description of the nonequilibrium stationary state of QC structures under an applied bias, and hence we determine transport properties, such as the current-voltage characteristic of these structures. We define two contributions to the current, one contribution driven by the scattering-free part of the Hamiltonian, and the other driven by the scattering Hamiltonian. We find that the dominant part of the current in these structures, in contrast to simple superlattice structures, is governed mainly by the scattering Hamiltonian. In addition, by considering the linear response of the stationary state of the structure to an applied optical field, we determine the linear susceptibility, and hence the gain or absorption spectra of the structure. A comparison of the spectra obtained from the more rigorous NGF theory with simpler models shows that the spectra tend to be offset to higher values in the simpler theories.Comment: 44 pages, 16 figures, appearing in Physical Review B Dec 200

Dating the Cryptococcus gattii Dispersal to the North American Pacific Northwest.

The emergence of Cryptococcus gattii, previously regarded as a predominantly tropical pathogen, in the temperate climate of the North American Pacific Northwest (PNW) in 1999 prompted several questions. The most prevalent among these was the timing of the introduction of this pathogen to this novel environment. Here, we infer tip-dated timing estimates for the three clonal C.&nbsp;gattii populations observed in the PNW, VGIIa, VGIIb, and VGIIc, based on whole-genome sequencing of 134 C.&nbsp;gattii isolates and using Bayesian evolutionary analysis by sampling trees (BEAST). We estimated the nucleotide substitution rate for each lineage (1.59 × 10-8, 1.59 × 10-8, and 2.70 × 10-8, respectively) to be an order of magnitude higher than common neutral fungal mutation rates (2.0 × 10-9), indicating a microevolutionary rate (e.g., successive clonal generations in a laboratory) in comparison to a species' slower, macroevolutionary rate (e.g., when using fossil records). The clonal nature of the PNW C.&nbsp;gattii emergence over a narrow number of years would therefore possibly explain our higher mutation rates. Our results suggest that the mean time to most recent common ancestor for all three sublineages occurred within the last 60 to 100&nbsp;years. While the cause of C.&nbsp;gattii dispersal to the PNW is still unclear, our research estimates that the arrival is neither ancient nor very recent (i.e., &lt;25 years ago), making a strong case for an anthropogenic introduction. IMPORTANCE The recent emergence of the pathogenic fungus Cryptococcus gattii in the Pacific Northwest (PNW) resulted in numerous investigations into the epidemiological and enzootic impacts, as well as multiple genomic explorations of the three primary molecular subtypes of the fungus that were discovered. These studies lead to the general conclusion that the subtypes identified likely emerged out of Brazil. Here, we conducted genomic dating analyses to determine the ages of the various lineages seen in the PNW and propose hypothetical causes for the dispersal events. Bayesian evolutionary analysis strongly suggests that these independent fungal populations in the PNW are all 60 to 100 years old, providing a timing that is subsequent to the opening of the Panama Canal, which allowed for more direct shipping between Brazil and the western North American coastline, a possible driving event for these fungal translocation events

Dyslipidemia among HIV-infected Patients with Tuberculosis Taking Once-daily Nonnucleoside Reverse-Transcriptase Inhibitor–Based Antiretroviral Therapy in India

HIV-infected patients with tuberculosis who initiate nonnucleoside reverse-transcriptase-based anti-retroviral treatment in combination with rifampicin-based antituberculosis treatment demonstrate increases in total cholesterol, low-density cholesterol, and high-density cholesterol levels but no change in blood glucose level after 1 year. Cholesterol increases were more frequent among patients receiving efavirenz