1,294 research outputs found
Coordination Dependence of Hyperfine Fields of 5sp Impurities on Ni Surfaces
We present first-principles calculations of the magnetic hyperfine fields H
of 5sp impurities on the (001), (111), and (110) surfaces of Ni. We examine the
dependence of H on the coordination number by placing the impurity in the
surfaces, on top of them at the adatom positions, and in the bulk. We find a
strong coordination dependence of H, different and characteristic for each
impurity. The behavior is explained in terms of the on-site s-p hybridization
as the symmetry is reduced at the surface. Our results are in agreement with
recent experimental findings.Comment: 4 pages, 3 figure
Decreased soluble guanylate cyclase contributes to cardiac dysfunction induced by chronic doxorubicin treatment in mice
Aims: The use of doxorubicin, a potent chemotherapeutic agent, is limited by cardiotoxicity. We tested the hypothesis that decreased soluble guanylate cyclase (sGC) enzyme activity contributes to the development of doxorubicin-induced cardiotoxicity. Results: Doxorubicin administration (20 mg/kg, intraperitoneally [IP]) reduced cardiac sGC activity in wild-type (WT) mice. To investigate whether decreased sGC activity contributes to doxorubicin-induced cardiotoxicity, we studied mice with cardiomyocyte-specific deficiency of the sGC alpha 1-subunit (mice with cardiomyocyte-specific deletion of exon 6 of the sGC alpha 1 allele [sGC alpha 1(-/-CM)]). After 12 weeks of doxorubicin administration (2 mg/kg/week IP), left ventricular (LV) systolic dysfunction was greater in sGC alpha 1(-/-CM) than WT mice. To further assess whether reduced sGC activity plays a pathogenic role in doxorubicin-induced cardiotoxicity, we studied a mouse model in which decreased cardiac sGC activity was induced by cardiomyocyte-specific expression of a dominant negative sGC alpha 1 mutant (DNsGC alpha 1) upon doxycycline removal (Tet-off). After 8 weeks of doxorubicin administration, DNsGC alpha 1(tg/+), but not WT, mice displayed LV systolic dysfunction and dilatation. The difference in cardiac function and remodeling between DNsGC alpha 1(tg/+) and WT mice was even more pronounced after 12 weeks of treatment. Further impairment of cardiac function was attenuated when DNsGC alpha 1 gene expression was inhibited (beginning at 8 weeks of doxorubicin treatment) by administering doxycycline. Furthermore, doxorubicin-associated reactive oxygen species generation was higher in sGC alpha 1-deficient than WT hearts. Innovation and Conclusion: These data demonstrate that a reduction in cardiac sGC activity worsens doxorubicin-induced cardiotoxicity in mice and identify sGC as a potential therapeutic target. Various pharmacological sGC agonists are in clinical development or use and may represent a promising approach to limit doxorubicin-associated cardiotoxicity
Physical activity to improve cognition in older adults: can physical activity programs enriched with cognitive challenges enhance the effects? A systematic review and meta-analysis
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Dementia and detectives: Alzheimer's disease in crime fiction
Fictional representations of dementia have burgeoned in recent years, and scholars have amply explored their double-edged capacity to promote tragic perspectives or normalising images of ‘living well’ with the condition. Yet to date, there has been only sparse consideration of the treatment afforded dementia within the genre of crime fiction. Focusing on two novels, Emma Healey’s Elizabeth is Missing and Alice LaPlante’s Turn of Mind, this article considers what it means in relation to the ethics of representation that these authors choose to cast as their amateur detective narrators women who have dementia. Analysing how their narrative portrayals frame the experience of living with dementia, it becomes apparent that features of the crime genre inflect the meanings conveyed. While aspects of the novels may reinforce problem-based discourses around dementia, in other respects they may spur meaningful reflection about it among the large readership of this genre
Polar and hydrogen-bonding effects of alcohols on the emission spectrum of styrene-triethylamine system
The emission spectra of styrene (ST)-triethylamine (TEA) systems were measured under steady-state illumination conditions in some THF-protic solvent mixtures. The fluorescence spectrum of the ST-TEA system in THF consists of two bands (band A at 304 nm (fluorescence of ST) and band B at 460 nm (emission from an exciplex)). The intensity of band A increased and that of band B decreased with increasing amounts of protic solvents in THF-protic solvent mixtures. The increase in the intensity of band A was explained by the decrease in the concentration of free amine owing to the hydrogen-bonding interaction (or protonation) between TEA and protic solvents. The decrease in the intensity of band B was considered to be caused by the decrease in the concentration of free amine on the addition of protic solvents and the enhanced conversion of the exciplex to an ion pair with increasing solvent polarity. The polar effect was expressed as a function of the relative permittivity of the solution.</p
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Transition and Agriculture
The overall objectives of our proposed paper is to: (a) systematically document the post-reform trends in agricultural performance in Asia, Europe, and the Former Soviet Union; (b) identify the main reform strategies and institutional innovations that have contributed to the successes and failures of the sector; (c) analyze the mechanisms by which reform policies and initial conditions have affected the transition process in agriculture; and (d) draw lessons and policy implications from the experiment and identify the gaps in our understanding of the role and performance of agriculture in transition.As part of this effort, we attempt to address a number of intriguing and important questions on the performance of individual countries or regions during transition. Why has China been so successful in its reforms, while Russia has not? Why is it that some CEECs have rebounded and showing robust productivity growth, while others have not? Why has agriculture in so many FSU nations continued to perform so poorly?In addition, we will address questions about the process of reform. Why has land restitution predominated in Europe but not in Russia or China? Why did institutions of exchange collapse in the non-Asian economies in the early stages of reform but continued to function in Vietnam and China? What explains the apparent divergence in the performance effects after the first year of reform in China and Vietnam, on the one hand, and much of the rest of the transitional world on the other? In particular, how have land reform and rural input-supply/procurement enterprise restructuring affected productivity? Which institutions of exchange and contracting have or have not emerged, and why? How has the structure of the economy at the outset of transition, and other initial conditions, affected the transition process?To meet our objectives and answer some of the questions, we will begin by laying out the record on performance — examining the main bodies of data that demonstrate the changes in agricultural output, income, and productivity in the years after transition. In doing so, we will show how some of the countries have recorded similar performances, while others have developed quite differently. We will identify several “patterns of transition” based on these performance indicators and much of our subsequent discussion will analyze the success of transition according to these classifications.Next, as the first step in our search for answers as to what explains these different patterns, we examine differences in the points of departure of the transition countries as well as the nature of the policy reforms that have affected agriculture. The initial conditions that we hypothesize may explain part of the transition period’s performance include the nature of agricultural technology at the beginning of the reforms (its scale; its labor intensiveness; etc.), the structure of the economy (the extent of industrialization), the extent of collectivization, and the magnitude of trade distortions. The key policy interventions that we should expect to affect agriculture’s performance during transition include land right reforms and farm restructuring; price and subsidization policies; the approach to the liberalization of agricultural commodity and input markets; general macro-economic and general institutional reforms; and the attention of sectoral leaders to the level of new and maintenance-oriented public goods investment (in agricultural research, irrigation, roads, and other infrastructure projects).After documenting the dramatic differences in initial conditions and in reform policies among the transitional countries, we seek to demonstrate which of the differences determine the path a country’s agriculture takes. In other words, we offer answers to the question why transition in agriculture in some countries has been successful and not in others. Here, we seek to generalize about the main causes for differences between the countries and the mechanisms that have affected performance. In particular, we argue that the debate on the optimality of Big-Bang versus gradualism oversimplifies the reform problem. The empirical evidence suggests that the road to a successful transition is more subtle and successful transitions in Asia and Europe have elements of both gradual and radical reforms. To explain the reform successes and failures we emphasize the role of the political environment in the early reform years and the potential for agricultural growth that exists at the start of reforms. We find that both have not only influenced the choice of the reform policies, but also the effect of the reform policies. We also conclude that the initial level of price distortions and the pace of market liberalization were especially influential in explaining differences in the early stages of transition but that the influence of the factors has diminished over time. Investment, land rights, and farm restructuring policies, in contrast, are assuming a more important role as the agricultural reforms have matured.In the last section we draw policy implications and lessons from the agricultural transition experiences. We argue that one should be careful about which indicator to use for measuring success and failure of transition. We conclude that all reform strategies in order to be successful need to include some certain policy ingredients (such as continued investment, etc.). However, a powerful lesson is that although all the pieces are ultimately needed, there is a lot of room for variation in the form of institutions that can be successful, and optimal policies and institutions may vary according to initial conditions. In other words, there is no single optimal transition path
Absence of thrombospondin-2 causes age-related dilated cardiomyopathy
BACKGROUND: The progressive shift from a young to an aged heart is characterized by alterations in the cardiac matrix. The present study investigated whether the matricellular protein thrombospondin-2 (TSP-2) may affect cardiac dimensions and function with physiological aging of the heart. METHODS AND RESULTS: TSP-2 knockout (KO) and wild-type mice were followed up to an age of 60 weeks. Survival rate, cardiac function, and morphology did not differ at a young age in TSP-2 KO compared with wild-type mice. However, >55% of the TSP-2 KO mice died between 24 and 60 weeks of age, whereas <10% of the wild-type mice died. In the absence of TSP-2, older mice displayed a severe dilated cardiomyopathy with impaired systolic function, increased cardiac dilatation, and fibrosis. Ultrastructural analysis revealed progressive myocyte stress and death, accompanied by an inflammatory response and replacement fibrosis, in aging TSP-2 KO animals, whereas capillary or coronary morphology or density was not affected. Importantly, adeno-associated virus-9 gene-mediated transfer of TSP-2 in 7-week-old TSP-2 KO mice normalized their survival and prevented dilated cardiomyopathy. In TSP-2 KO animals, age-related cardiomyopathy was accompanied by increased matrix metalloproteinase-2 and decreased tissue transglutaminase-2 activity, together with impaired collagen cross-linking. At the cardiomyocyte level, TSP-2 deficiency in vivo and its knockdown in vitro decreased the activation of the Akt survival pathway in cardiomyocytes. CONCLUSIONS: TSP-2 expression in the heart protects against age-dependent dilated cardiomyopath
Transfer of learning between unimanual and bimanual rhythmic movement coordination: transfer is a function of the task dynamic.
Under certain conditions, learning can transfer from a trained task to an untrained version of that same task. However, it is as yet unclear what those certain conditions are or why learning transfers when it does. Coordinated rhythmic movement is a valuable model system for investigating transfer because we have a model of the underlying task dynamic that includes perceptual coupling between the limbs being coordinated. The model predicts that (1) coordinated rhythmic movements, both bimanual and unimanual, are organised with respect to relative motion information for relative phase in the coupling function, (2) unimanual is less stable than bimanual coordination because the coupling is unidirectional rather than bidirectional, and (3) learning a new coordination is primarily about learning to perceive and use the relevant information which, with equal perceptual improvement due to training, yields equal transfer of learning from bimanual to unimanual coordination and vice versa [but, given prediction (2), the resulting performance is also conditioned by the intrinsic stability of each task]. In the present study, two groups were trained to produce 90° either unimanually or bimanually, respectively, and tested in respect to learning (namely improved performance in the trained 90° coordination task and improved visual discrimination of 90°) and transfer of learning (to the other, untrained 90° coordination task). Both groups improved in the task condition in which they were trained and in their ability to visually discriminate 90°, and this learning transferred to the untrained condition. When scaled by the relative intrinsic stability of each task, transfer levels were found to be equal. The results are discussed in the context of the perception–action approach to learning and performance
Subsidies and agricultural productivity in the EU
This paper investigates the relationship between EU agricultural subsidies and agricultural labor productivity growth by estimating a conditional convergence growth model. We use more representative subsidy indicators and a wider coverage (panel data from 213 EU regions over the period 2004\u20132014) than have been used before. We find that, on average, EU's Common Agricultural Policy (CAP) subsidies increase agricultural labor productivity growth, but this aggregate effect hides important heterogeneity of effects of different types of subsidies. The positive effect on productivity comes from decoupled subsidies, that is, Pillar I decoupled payments and some Pillar II payments. Coupled Pillar I subsidies have the opposite effect: they slow down productivity growth
Comparative study: the effect of annealing conditions on the properties of P3HT:PCBM blends
This paper presents a detailed study on the role of various annealing treatments on organic poly(3-hexylthiophene) and [6]-phenyl-C61-butyric acid methyl ester blends under different experimental conditions. A combination of analytical tools is used to study the alteration of the phase separation, structure and photovoltaic properties of the P3HT:PCBM blend during the annealing process. Results showed that the thermal annealing yields PCBM ‘‘needle-like’’ crystals and that prolonged heat treatment leads to extensive phase separation, as demonstrated by the growth in the size and quantity of PCBM crystals. The substrate annealing method demonstrated an optimal morphology by eradicating and suppressing the formation of fullerene clusters across the film, resulting in longer P3HT fibrils with smaller diameter. Improved optical constants, PL quenching and a decrease in the P3HT optical bad-gap were demonstrated for the substrate annealed films due to the limited diffusion of the PCBM molecules. An effective strategy for determining an optimized morphology through substrate annealing treatment is therefore revealed for improved device efficiency.Web of Scienc
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