Optical properties of chalcopyrite-type intermediate transition metal band materials from first principles

The optical properties of a novel potential high-efficiency photovoltaic material have been studied. This material is based on a chalcopyrite-type semiconductor (CuGaS2) with some Ga atom substituted by Ti and is characterized by the formation of an isolated transition-metal band between the valence band and the conduction band. We present a study in which ab-initio density functional theory calculations within the generalized gradient approximation are carried out to determine the optical reflectivity and absorption coefficient of the materials of interest. Calculations for the host semiconductor are in good agreement with experimental results within the limitations of the approach. We find, as desired, that because of the intermediate band, the new Ti-substituted material would be able to absorb photons of energy lower than the band-gap of the host chalcopyrite. We also analyze the partial contributions to the main peaks of its spectrum

Does social context impact metacognition? Evidence from stereotype threat in a visual search task

While recent studies have emphasized the role of metacognitive judgments in social interactions, whether social context might reciprocally impact individuals’ metacognition remains an open question. It has been proposed that such might be the case in situations involving stereotype threat. Here, we provide the first empirical test of this hypothesis. Using a visual search task, we asked participants, on a trial-by-trial basis, to monitor the unfolding and accuracy of their search processes, and we developed a computational model to measure the accuracy of their metacognition. Results indicated that stereotype threat enhanced metacognitive monitoring of both outcomes and processes. Our study thus shows that social context can actually affect metacognition

Production of Long Chain Fatty Alcohols Found in Bumblebee Pheromones by Yarrowia lipolytica

Fatty alcohols (FA-OH) are aliphatic unbranched primary alcohols with a chain of four or more carbon atoms. Besides potential industrial applications, fatty alcohols have important biological functions as well. In nature, fatty alcohols are produced as a part of a mixture of pheromones in several insect species, such as moths, termites, bees, wasps, etc. In addition, FA-OHs have a potential for agricultural applications, for example, they may be used as a suitable substitute for commercial insecticides. The insecticides have several drawbacks associated with their preparation, and they exert a negative impact on the environment. Currently, pheromone components are prepared mainly through the catalytic hydrogenation of plant oils and petrochemicals, which is an unsustainable, ecologically unfriendly, and highly expensive process. The biotechnological production of the pheromone components using engineered microbial strains and through the expression of the enzymes participating in the biosynthesis of these components is a promising approach that ensures ecological sustenance as well. The present study was aimed at evaluating the production of FA-OHs in the oleaginous yeast, Yarrowia lipolytica, with different lengths of fatty-acyl chains by expressing the fatty acyl-CoA reductase (FAR) BlapFAR4 from B. lapidarius, producing C16:0-OH, C16:1Δ9-OH, and lower quantities of both C14:0-OH and C18:1Δ9-OH, and BlucFAR1 from B. lucorum, producing FA-OHs with a chain length of 18–26 carbon atoms, in this yeast. Among the different novel Y. lipolytica strains used in the present study, the best results were obtained with JMY7086, which carried several lipid metabolism modifications and expressed the BlucFAR1 gene under the control of a strong constitutive promoter 8UAS-pTEF. JMY7086 produced only saturated fatty alcohols with chain lengths from 18 to 24 carbon atoms. The highest titer and accumulation achieved were 166.6 mg/L and 15.6 mg/g DCW of fatty alcohols, respectively. Unlike JMY7086, the BlapFAR4-expressing strain JMY7090 produced only 16 carbon atom-long FA-OHs with a titer of 14.6 mg/L

Welding dynamics in an atomistic model of an amorphous polymer blend with polymer-polymer interface

We consider an atomistic model of thermal welding at the polymer-polymer interface of a polyetherimide/polycarbonate blend, motivated by applications to 3D manufacturing in space. We follow diffusion of semiflexible chains at the interface and analyze strengthening of the samples as a function of the welding time tw by simulating the strain-stress and shear viscosity curves. The time scales for initial wetting, and for fast and slow diffusion, are revealed. It is shown that each component of the polymer blend has its own characteristic time of slow diffusion at the interface. Analysis of strainstress demonstrates saturation of the Young’s modulus at tw = 240 ns, while the tensile strength continues to increase. The shear viscosity is found to have a very weak dependence on the welding time for tw > 60 ns. It is shown that both strain-stress and shear viscosity curves agree with experimental data

Reasons and Means to Model Preferences as Incomplete

Literature involving preferences of artificial agents or human beings often assume their preferences can be represented using a complete transitive binary relation. Much has been written however on different models of preferences. We review some of the reasons that have been put forward to justify more complex modeling, and review some of the techniques that have been proposed to obtain models of such preferences

Quantification of the response of circulating epithelial cells to neodadjuvant treatment for breast cancer: a new tool for therapy monitoring

INTRODUCTION: In adjuvant treatment for breast cancer there is no tool available with which to measure the efficacy of the therapy. In contrast, in neoadjuvant therapy reduction in tumour size is used as an indicator of the sensitivity of tumour cells to the agents applied. If circulating epithelial (tumour) cells can be shown to react to therapy in the same way as the primary tumour, then this response may be exploited to monitor the effect of therapy in the adjuvant setting. METHOD: We used MAINTRAC(® )analysis to monitor the reduction in circulating epithelial cells during the first three to four cycles of neoadjuvant therapy in 30 breast cancer patients. RESULTS: MAINTRAC(® )analysis revealed a patient-specific response. Comparison of this response with the decline in size of the primary tumour showed that the reduction in number of circulating epithelial cells accurately predicted final tumour reduction at surgery if the entire neoadjuvant regimen consisted of chemotherapy. However, the response of the circulating tumour cells was unable to predict the response to additional antibody therapy. CONCLUSION: The response of circulating epithelial cells faithfully reflects the response of the whole tumour to adjuvant therapy, indicating that these cells may be considered part of the tumour and can be used for therapy monitoring

Elicitation of Preferences under Ambiguity

This paper is about behaviour under ambiguity ‒ that is, a situation in which probabilities either do not exist or are not known. Our objective is to find the most empirically valid of the increasingly large number of theories attempting to explain such behaviour. We use experimentally-generated data to compare and contrast the theories. The incentivised experimental task we employed was that of allocation: in a series of problems we gave the subjects an amount of money and asked them to allocate the money over three accounts, the payoffs to them being contingent on a ‘state of the world’ with the occurrence of the states being ambiguous. We reproduced ambiguity in the laboratory using a Bingo Blower. We fitted the most popular and apparently empirically valid preference functionals [Subjective Expected Utility (SEU), MaxMin Expected Utility (MEU) and α­-MEU], as well as Mean-Variance (MV) and a heuristic rule, Safety First (SF). We found that SEU fits better than MV and SF and only slightly worse than MEU and α­-MEU

Stage and treatment variation with age in postmenopausal women with breast cancer: compliance with guidelines

Breast cancer-specific mortality is static in older women despite having fallen in younger age groups, possibly due to lack of screening and differences in treatment. This study compared stage and treatment between two cohorts of postmenopausal women (55–69 vs 470 years) in a single cancer network over 6 months. A total of 378 patients were studied (470: N ¼ 167, 55–69 years: N ¼ 210). Older women presented with more advanced disease (470: metastatic/locally advanced 12%, 55–69 years: 3%, Po0.01). Those with operable cancer had a worse prognosis (Nottingham Prognostic Index (NPI) 470: median NPI 4.4, 55–69 years: 4.25, Po0.03). These stage differences were partially explained by higher screening rates in the younger cohort. Primary endocrine therapy was used in 42% of older patients compared with 3% in the younger group (Po0.001). Older women with cancers suitable for breast conservation were more likely to choose mastectomy (470: 57.5% mastectomy rate vs 55–69 years: 20.6%, Po0.01). Nodal surgery was less frequent in older patients (470: 6.7% no nodal surgery, 55–69 years: 0.5%, Po0.01) and was more likely to be inadequate (470: 10.7% o4 nodes excised, 55–69 years: 3.4%, Po0.02). In summary, older women presented with more advanced breast cancer, than younger postmenopausal women and were treated less comprehensively

Revisiting the Transit Timing Variations in the TrES-3 and Qatar-1 Systems with TESS Data

We present and analyze 58 transit light curves of TrES-3b and 98 transit light curves of Qatar-1b, observed by the Transiting Exoplanet Survey Satellite, plus two transit light curves of Qatar-1b, observed by us, using a ground-based 1.23 m telescope. These light curves are combined with the best-quality light curves taken from the Exoplanet Transit Database and the literature. The precisely determined midtransit times from these light curves enable us to obtain the refined orbital ephemerides, with improved precision, for both hot Jupiters. From the timing analysis, we find indications of the presence of transit timing variations (TTVs) in both systems. Since the observed TTVs are unlikely to be short-term and periodic, the possibility of additional planets in orbits close to TrES-3b and Qatar-1b is ruled out. The possible causes of long-term TTVs, such as orbital decay, apsidal precession, the Applegate mechanism, and line-of-sight acceleration, are also examined. However, none of these possibilities are found to explain the observed TTV of TrES-3b. In contrast to this, line-of-sight acceleration appears to be a plausible explanation for the observed TTV of Qatar-1b. In order to confirm these findings, further high-precision transit and radial velocity observations of both systems would be worthwhile

Measuring loss aversion under ambiguity: a method to make prospect theory completely observable

We propose a simple, parameter-free method that, for the first time, makes it possible to completely observe Tversky and Kahneman’s (1992) prospect theory. While methods exist to measure event weighting and the utility for gains and losses separately, there was no method to measure loss aversion under ambiguity. Our method allows this and thereby it can measure prospect theory’s entire utility function. Consequently, we can properly identify properties of utility and perform new tests of prospect theory. We implemented our method in an experiment and obtained support for prospect theory. Utility was concave for gains and convex for losses and there was substantial loss aversion. Both utility and loss aversion were the same for risk and ambiguity, as assumed by prospect theory, and sign-comonotonic trade-off consistency, the central condition of prospect theory, held