7,226 research outputs found

    Epitaxial growth and thermodynamic stability of SrIrO3/SrTiO3 heterostructures

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    Obtaining high-quality thin films of 5d transition metal oxides is essential to explore the exotic semimetallic and topological phases predicted to arise from the combination of strong electron correlations and spin-orbit coupling. Here, we show that the transport properties of SrIrO3 thin films, grown by pulsed laser deposition, can be optimized by considering the effect of laser-induced modification of the SrIrO3 target surface. We further demonstrate that bare SrIrO3 thin films are subject to degradation in air and are highly sensitive to lithographic processing. A crystalline SrTiO3 cap layer deposited in-situ is effective in preserving the film quality, allowing us to measure metallic transport behavior in films with thicknesses down to 4 unit cells. In addition, the SrTiO3 encapsulation enables the fabrication of devices such as Hall bars without altering the film properties, allowing precise (magneto)transport measurements on micro- and nanoscale devices.Comment: 5 pages, 3 figure

    Perioperative hemodynamic goal-directed therapy and mortality: a systematic review and meta-analysis with meta-regression

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    INTRODUCTION: Recent data found that perioperative goal directed therapy (GDT) was effective only in higher control mortality rates (> 20%) with a relatively high heterogeneity that limited the strength of evidence. The aim of the present meta-analysis was to clearly understand which high risk patients may benefit of GDT.EVIDENCE ACQUISITION: Systematic review of randomized controlled trials with meta-analyses, including a meta-regression technique. MEDLINE, EMBASE, and The Cochrane Library databases were searched (1980-January 2015). Trials enrolling adult surgical patients and comparing the effects of GDT versus standard hemodynamic therapy were considered. The primary outcome measure was mortality. Data synthesis was obtained by using Odds Ratio (OR) with 95% confidence interval (CI) by random-effects model.EVIDENCE SYNTHESIS: Fifty eight studies met the inclusion criteria (8171 participants). Pooled OR for mortality was 0.70 (95% CI 0.56-0.88, P= 0.002, no statistical heterogeneity). GDT significantly reduced mortality when it is > 10% in control group (OR 0.43, 95% CI 0.30-0.61, P< 0.00001). The meta-regression model showed that the cut off of 10% of mortality rate in control group significantly differentiates 43 studies from the other 15, with a regression coefficient b of -0.033 and a P value of 0.0001. The significant effect of GDT was driven by high risk of bias studies (OR 0.48, 95% CI 0.34-0.67, P< 0.0001).CONCLUSIONS: The present meta-analysis, adopting the meta-regression technique, suggests that GDT significantly reduces mortality even when the event control rate is > 10%

    Paleolimnological evidence for increased sexual reproduction in chydorids (Chydoridae, Cladocera) under environmental stress

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    To investigate the extent to which anthropogenic perturbations such as eutrophication and trace metal pollution (i.e., environmental stress sensu Odum 1985) influence the reproductive modes of cladoceran populations, we analyzed the abundance of subfossils of the chydorids Alonella nana (Baird, 1850) and Alona affinis (Leydig, 1860) in sediment cores from three Finnish lakes. Reconstruction of lakes\u27 pollutant history and the biological response of chydorids indicate that in two of the lakes the proportion of individuals reproducing sexually increased with environmental stressors. More specifically, A. nana responded to eutrophication in Lake Hamptr?sk with greater production of ephippia, while A. affinis responded to aluminum pollution or acidification in Lake Pieni Majaslampi. In contrast, the reference lake, Lake Iso Lehm?lampi, showed no radical changes in sexual reproduction over the twomillennium long sediment record. We conclude that chydorids may use sexual reproduction as a strategy for overcoming unexpected environmental stresses

    Modelling the influence of peers’ attitudes on choice behaviour: theory and empirical application on electric vehicle preferences

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    While the importance of social influence on transport-related choices is commonly acknowledged within the transport and travel behaviour research community, there remain several challenges in modelling influence in practice. This paper proposes a new analytical approach to measure the effects of attitudes of peers on the decision making process of the individual. Indeed, while most of the previous literature focused its attention on capturing conformity to a certain real or hypothetical choice, we investigate the subtle effect of attitudes that underlies this choice. Specifically, the suggested measure enables us to model the correlated effect that might indirectly affect the individual’s choice within a social group. It combines detailed information on the attitudes in the individual’s social network and the social proximity of the individuals in the social network. To understand its behavioural implications on the individual’s choice, the individual’s peer attitude variable is tested in different components of a hybrid choice model. Our results show that the inclusion of this variable indirectly affects the decision making process of the individual as the peers’ attitudes are significantly related to the latent attitude of the individual. On the other hand, it does not seem to directly affect the utility of an alternative as a source of systematic heterogeneity nor does it work as a manifestation of the latent variable, i.e. as an indicator

    Towards Micromechanical Sensors with (La,Sr)MnO3 Epitaxial Films☆

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    Abstract The rich spectrum of functionalities exhibited by oxide thin films is an appealing feature for the development of micro and nanomechanical devices [1,2] . MEMS made of heterostructures of crystalline oxide materials having targeted physical properties may be applied as sensors having different integrated functionalities. In this work, we explore the feasibility of manganite thin film based epitaxial MEMS for magnetic micromechanical sensing. We investigate the electromechanical properties of LSMO freestanding structures for future applications in the field of micromechanical magnetic sensors

    Deterministic and stochastic P systems for modelling cellular processes

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    This paper presents two approaches based on metabolic and stochastic P systems, together with their associated analysis methods, for modelling biological sys- tems and illustrates their use through two case studies.Kingdom's Engineering and Physical Sciences Research Council EP/ E017215/1Biotechnology and Biological Sciences Research Council/United Kingdom BB/D019613/1Biotechnology and Biological Sciences Research Council/United Kingdom BB/F01855X/

    Ceramic Substrates for High-temperature Electronic Integration

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    One of the most attractive ways to increase power handling capacity in power modules is to increase the operating temperature using wide-band-gap semiconductors. Ceramics are ideal candidates for use as substrates in high-power high-temperature electronic devices. The present article aims to determine the most suitable ceramic material for this application

    Identification of hydrodynamic changes in rivers by means of freshwater mussels' behavioural response: An experimental investigation

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    The present work concerns the interaction between hydraulic processes and biological communities in rivers. In particular, the aim of this study is to investigate the interactions between flow dynamics and the freshwater mussels (FMs) to verify if the mussels' behavioural response to the hydrodynamic stress could be used to monitor natural extreme events in rivers. Although the influence of mussels on the kinematic characteristics of flow at the water–sediment interface was investigated by a certain number of studies, their behavioural response to flow, both in static and dynamic conditions, remains understudied. Laboratory experiments were performed in an artificial flume exposing Unio elongatulus to different values of flow discharge, both in steady and in unsteady conditions either with or without sediment transport. Mussels' behavioural responses were detected by using Hall sensor technology to measure gaping frequency, amplitude and duration, both in static conditions and under the effect of hydrodynamic stresses. Five categories of behavioural response were identified: Normal Activity (NA), Resting (Re), Transition (Tr), Adaptation (Ad) and Avoidance (Av). During NA (standard feeding and moving), FMs presented valve gaping, while during Re valves were kept constantly opened for water filtration. After a variation of flow discharge (ΔQ), FMs promptly reacted showing a transition from their normal behaviour, with constant gaping frequency (below 0.01 Hz), to higher valve gaping frequencies. The mean valves' gaping frequency increased as a function of ΔQ, and the highest values were reached in the presence of sediment transport. The mean valve opening amplitude was less sensitive to ΔQ. Its range of variation was very narrow with the highest values corresponding to the protrusion/retraction of the animals' foot to move or anchor to the substrate. The percentage of mussels responding to the discharge variation (Transition behaviour) increases with ΔQ confirming that mussels' behavioural response represents a promising tool for monitoring the occurrence of hydrodynamic stressors in fluvial systems

    Use of the multivariate discriminant analysis for genome-wide association studies in cattle

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    Genome-wide association studies (GWAS) are traditionally carried out by using the single marker regression model that, if a small number of individuals is involved, often lead to very few associations. The Bayesian methods, such as BayesR, have obtained encouraging results when they are applied to the GWAS. However, these approaches, require that an a priori posterior inclusion probability threshold be fixed, thus arbitrarily affecting the obtained associations. To partially overcome these problems, a multivariate statistical algorithm was proposed. The basic idea was that animals with different phenotypic values of a specific trait share different allelic combinations for genes involved in its determinism. Three multivariate techniques were used to highlight the differences between the individuals assembled in high and low phenotype groups: the canonical discriminant analysis, the discriminant analysis and the stepwise discriminant analysis. The multivariate method was tested both on simulated and on real data. The results from the simulation study highlighted that the multivariate GWAS detected a greater number of true associated single nucleotide polymorphisms (SNPs) and Quantitative trait loci (QTLs) than the single marker model and the Bayesian approach. For example, with 3000 animals, the traditional GWAS highlighted only 29 significantly associated markers and 13 QTLs, whereas the multivariate method found 127 associated SNPs and 65 QTLs. The gap between the two approaches slowly decreased as the number of animals increased. The Bayesian method gave worse results than the other two. On average, with the real data, the multivariate GWAS found 108 associated markers for each trait under study and among them, around 63% SNPs were also found in the single marker approach. Among the top 118 associated markers, 76 SNPs harbored putative candidate genes
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