309 research outputs found
On the classification of Kahler-Ricci solitons on Gorenstein del Pezzo surfaces
We give a classification of all pairs (X,v) of Gorenstein del Pezzo surfaces
X and vector fields v which are K-stable in the sense of Berman-Nystrom and
therefore are expected to admit a Kahler-Ricci solition. Moreover, we provide
some new examples of Fano threefolds admitting a Kahler-Ricci soliton.Comment: 21 pages, ancillary files containing calculations in SageMath; minor
correction
Pre-Cretaceous Agaricomycetes yet to be discovered: Reinvestigation of a putative Triassic bracket fungus from southern Germany
Identification of interface structure for a topological CoS<sub>2</sub> single crystal in oxygen evolution reaction with high intrinsic reactivity
Transition metal chalcogenides such as CoS2 have been reported as competitive catalysts for oxygen evolution reaction. It has been well confirmed that surface modification is inevitable in such a process, with the formation of different re-constructed oxide layers. However, which oxide species should be responsible for the optimized catalytic efficiencies and the detailed interface structure between the modified layer and precatalyst remain controversial. Here, a topological CoS2 single crystal with a well-defined exposed surface is used as a model catalyst, which makes the direct investigation of the interface structure possible. Cross-sectional transmission electron microscopy of the sample reveals the formation of a 2 nm thickness Co3O4 layer that grows epitaxially on the CoS2 surface. Thick CoO pieces are also observed and are loosely attached to the bulk crystal. The compact Co3O4 interface structure can result in the fast electron transfer from adsorbed O species to the bulk crystal compared with CoO pieces as evidenced by the electrochemical impedance measurements. This leads to the competitive apparent and intrinsic reactivity of the crystal despite the low surface geometric area. These findings are helpful for the understanding of catalytic origins of transition metal chalcogenides and the designing of high-performance catalysts with interface-phase engineering
Does working memory training have to be adaptive?
This study tested the common assumption that, to be most effective, working memory (WM) training should be adaptive (i.e., task difficulty is adjusted to individual performance). Indirect evidence for this assumption stems from studies comparing adaptive training to a condition in which tasks are practiced on the easiest level of difficulty only [cf. Klingberg (Trends Cogn Sci 14:317-324, 2010)], thereby, however, confounding adaptivity and exposure to varying task difficulty. For a more direct test of this hypothesis, we randomly assigned 130 young adults to one of the three WM training procedures (adaptive, randomized, or self-selected change in training task difficulty) or to an active control group. Despite large performance increases in the trained WM tasks, we observed neither transfer to untrained structurally dissimilar WM tasks nor far transfer to reasoning. Surprisingly, neither training nor transfer effects were modulated by training procedure, indicating that exposure to varying levels of task difficulty is sufficient for inducing training gains
Experimental signatures of the mixed axial-gravitational anomaly in the Weyl semimetal NbP
Weyl semimetals are materials where electrons behave effectively as a kind of
massless relativistic particles known asWeyl fermions. These particles occur in
two flavours, or chiralities, and are subject to quantum anomalies, the
breaking of a conservation law by quantum fluctuations. For instance, the
number of Weyl fermions of each chirality is not independently conserved in
parallel electric and magnetic field, a phenomenon known as the chiral anomaly.
In addition, an underlying curved spacetime provides a distinct contribution to
a chiral imbalance, an effect known as the mixed axial-gravitational anomaly,
which remains experimentally elusive. However, the presence of a mixed
gauge-gravitational anomaly has recently been tied to thermoelectrical
transport in a magnetic field, even in flat spacetime, opening the door to
experimentally probe such type of anomalies in Weyl semimetals. Using a
temperature gradient, we experimentally observe a positive longitudinal
magnetothermoelectric conductance (PMTC) in the Weyl semimetal NbP for
collinear temperature gradients and magnetic fields (DT || B) that vanishes in
the ultra quantum limit. This observation is consistent with the presence of a
mixed axial-gravitational anomaly. Our work provides clear experimental
evidence for the existence of a mixed axial-gravitational anomaly of Weyl
fermions, an outstanding theoretical concept that has so far eluded
experimental detection
The comorbidity and co-medication profile of patients with progressive supranuclear palsy
BackgroundProgressive supranuclear palsy (PSP) is usually diagnosed in elderly. Currently, little is known about comorbidities and the co-medication in these patients.ObjectivesTo explore the pattern of comorbidities and co-medication in PSP patients according to the known different phenotypes and in comparison with patients without neurodegenerative disease.MethodsCross-sectional data of PSP and patients without neurodegenerative diseases (non-ND) were collected from three German multicenter observational studies (DescribePSP, ProPSP and DANCER). The prevalence of comorbidities according to WHO ICD-10 classification and the prevalence of drugs administered according to WHO ATC system were analyzed. Potential drug-drug interactions were evaluated using AiDKlinik (R).ResultsIn total, 335 PSP and 275 non-ND patients were included in this analysis. The prevalence of diseases of the circulatory and the nervous system was higher in PSP at first level of ICD-10. Dorsopathies, diabetes mellitus, other nutritional deficiencies and polyneuropathies were more frequent in PSP at second level of ICD-10. In particular, the summed prevalence of cardiovascular and cerebrovascular diseases was higher in PSP patients. More drugs were administered in the PSP group leading to a greater percentage of patients with polypharmacy. Accordingly, the prevalence of potential drug-drug interactions was higher in PSP patients, especially severe and moderate interactions.ConclusionsPSP patients possess a characteristic profile of comorbidities, particularly diabetes and cardiovascular diseases. The eminent burden of comorbidities and resulting polypharmacy should be carefully considered when treating PSP patients
Socio-demographic and practice-oriented factors related to proficiency in problem solving: a lifelong learning perspective
This article explores the relative importance of different socio-demographic and practice-oriented factors that are related to proficiency in problem solving in technology-rich environments (PSTREs) and by extension may be related to complex problem solving (CPS). The empirical analysis focuses on the proficiency measurements of PSTRE made available by the Programme for the International Assessment of Adult Competencies, which is relevant for gaining insight on some of the factors related to CPS. The purpose was to examine the relationship between the broad information processing experience that individuals gather in different contexts over the lifespan, and the chances to develop problem-solving skills that adults receive in different socio-demographic profiles. Results reveal that socio-demographic factors such as age, education and immigration status as well as practice-oriented factors such as ICT use and reading practice at and outside work are strongly related to proficiency
Psychologische Erkenntnisse zum Umgang mit komplexen Problemstellungen und zu Bedingungen kreativer Problemlösungen
The role of prefrontal cortex in working-memory capacity, executive attention, and general fluid intelligence: An individual-differences perspective
Steering the future. The emergence of “Western” futures research and its production of expertise, 1950s to early 1970s
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