408 research outputs found
Changes in the Occupational Structure of the Labour Market in Poland in 1995-2016
Within last few years Polish labour market has undergone significant structural changes, where the main labour markets policy challenges moved from the problem of fighting
unemployment to the problem of labour market shortages and the issue of increasing allocation effectiveness of labour force. This situation creates the need for building new and updating the
existing quantitative diagnostic tools that can be useful for providing labour market policy guidelines. As a result, the main objective of the article is to conduct re-specification of the
occupational model for major occupational groups with a high adjustment to empirical data and good statistical properties, which could be applied for forecasting purposes. To fulfil the aim of
the article the causal model econometric model for major occupational groups in Poland in the years 1995-2016 was re-specified. From the forecasting perspective the obtained model is
currently the most updated tool with respect to the occupational structure in Polish labour market, which in the same time is characterised with sufficient statistical quality. From the economic
perspective the research confirms the process of modernisation of Polish economy and the structural changes that are conducive to the tendencies observed in the EU-27 countries
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
A yeast-based tool for screening mammalian diacylglycerol acyltransferase inhibitors
Dysregulation of lipid metabolism is associated with obesity and metabolic diseases but there is also increasing evidence of a relationship between lipid body excess and cancer. Lipid body synthesis requires diacylglycerol acyltransferases (DGATs) which catalyze the last step of triacylglycerol synthesis from diacylglycerol and acyl-coenzyme A. The DGATs and in particular DGAT2, are therefore considered potential therapeutic targets for the control of these pathologies. Here, the murine and the human DGAT2 were overexpressed in the oleaginous yeast Yarrowia lipolytica deleted for all DGAT activities, to evaluate the functionality of the enzymes in this heterologous host and DGAT activity inhibitors. This work provides evidence that mammalian DGATs expressed in Y. lipolytica are a useful tool for screening chemical libraries to identify potential inhibitors or activators of these enzymes of therapeutic interest
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
Treatment of Myasthenia Gravis Based on Its Immunopathogenesis
The prognosis of myasthenia gravis (MG) has improved dramatically due to advances in critical-care medicine and symptomatic treatments. Its immunopathogenesis is fundamentally a T-cell-dependent autoimmune process resulting from loss of tolerance toward self-antigens in the thymus. Thymectomy is based on this immunological background. For MG patients who are inadequately controlled with sufficient symptomatic treatment or fail to achieve remission after thymectomy, remission is usually achieved through the addition of other immunotherapies. These immunotherapies can be classified into two groups: rapid induction and long-term maintenance. Rapid induction therapy includes intravenous immunoglobulin (IVIg) and plasma exchange (PE). These produce improvement within a few days after initiation, and so are useful for acute exacerbation including myasthenic crisis or in the perioperative period. High-dose prednisone has been more universally preferred for remission induction, but it acts more slowly than IVIg and PE, commonly only after a delay of several weeks. Slow tapering of steroids after a high-dose pulse offers a method of maintaining the state of remission. However, because of significant side effects, other immunosuppressants (ISs) are frequently added as "steroid-sparing agents". The currently available ISs exert their immunosuppressive effects by three mechanisms: 1) blocking the synthesis of DNA and RNA, 2) inhibiting T-cell activation and 3) depleting the B-cell population. In addition, newer drugs including antisense molecule, tumor necrosis factor alpha receptor blocker and complement inhibitors are currently under investigation to confirm their effectiveness. Until now, the treatment of MG has been based primarily on experience rather than gold-standard evidence from randomized controlled trials. It is hoped that well-organized studies and newer experimental trials will lead to improved treatments
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
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 αÂ-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 αÂ-MEU
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