Проблемы нуклеосинтеза. Куда исчез литий?

В данной статье рассматриваются проблемы нуклеосинтеза во Вселенной - процесса образованияядер химических элементов тяжелее водорода в ходе реакции ядерного синтеза. В статье анализируютсяактуальные научные работы, выдвигающие или опровергающие различные гипотезы, объясняющиевозможные причины дисбаланса лития во Вселенной. Проведенный анализ и составленный обзор научныхработ позволили сделать общий вывод о современном состоянии и перспективах исследований по проблеметеории большого взрыва.Im vorliegenden Artikel werden die Probleme der Nucleosynthese im Weltall - der Entstehung vonAtomkernen kurz nach dem Urknall - betrachtet. Im Artikel werden auch die neuesten wissenschaftlichen Arbeitenzum Thema "Abgleichfehler von Lithium im Universum", die verschiedene Hypothesen vom angegebenen Probleminterpretieren, analysiert. Aufgrund der durchgefuhrten Analyse wird die allgemeine Schlussfolgerung uber dasProblem von der Urknall-Theorie und die Perspektiven ihrer weiteren Erforschung gemacht

Instantons on sine-cones over Sasakian manifolds

We investigate instantons on sine-cones over Sasaki-Einstein and 3-Sasakian manifolds. It is shown that these conical Einstein manifolds are K"ahler with torsion (KT) manifolds admitting Hermitian connections with totally antisymmetric torsion. Furthermore, a deformation of the metric on the sine-cone over 3-Sasakian manifolds allows one to introduce a hyper-K"ahler with torsion (HKT) structure. In the large-volume limit these KT and HKT spaces become Calabi-Yau and hyper-K"ahler conifolds, respectively. We construct gauge connections on complex vector bundles over conical KT and HKT manifolds which solve the instanton equations for Yang-Mills fields in higher dimensions.Comment: 1+15 pages, 2 figure

Overburdening of peer review: A multi-stakeholder perspective on causes and effects

Peer review of manuscripts is labour-intensive and time-consuming. Individual reviewers might feel themselves overburdened with the amount of reviewing they are requested to do. Aiming to explore how stakeholder groups perceive reviewing burden and what they believe to be the causes of a potential overburdening of reviewers, we conducted focus groups with early-, mid-, and senior career scholars, editors, and publishers. By means of a thematic analysis, we aimed to identify the causes of overburdening of reviewers. First, we show that, across disciplines and roles, stakeholders believed that the reviewing burden is distributed unequally across members of the academic community, resulting in the overburdening of small groups of reviewers. Second, stakeholders believed this to be caused by (i) an increase in manuscript submissions; (ii) inefficient manuscript handling; (iii) lack of institutionalization of peer review; (iv) lack of reviewing instructions and (v) inadequate reviewer recruiting strategies. These themes were assumed to relate to an inadequate incentive structure in academia that favours publications over peer review. In order to alleviate reviewing burden, a holistic approach is required that addresses both the increased demand for and the insufficient supply of reviewing resources

Syk-dependent Phosphorylation of CLEC-2: A Novel Mechanism of Hem-Immunoreceptor Tyrosine-Based Activation Motif Signaling

The C-type lectin-like receptor CLEC-2 signals via phosphorylation of a single cytoplasmic YXXL sequence known as a hem-immunoreceptor tyrosine-based activation motif (hemITAM). In this study, we show that phosphorylation of CLEC-2 by the snake toxin rhodocytin is abolished in the absence of the tyrosine kinase Syk but is not altered in the absence of the major platelet Src family kinases, Fyn, Lyn, and Src, or the tyrosine phosphatase CD148, which regulates the basal activity of Src family kinases. Further, phosphorylation of CLEC-2 by rhodocytin is not altered in the presence of the Src family kinase inhibitor PP2, even though PLCγ2 phosphorylation and platelet activation are abolished. A similar dependence of phosphorylation of CLEC-2 on Syk is also seen in response to stimulation by an IgG mAb to CLEC-2, although interestingly CLEC-2 phosphorylation is also reduced in the absence of Lyn. These results provide the first definitive evidence that Syk mediates phosphorylation of the CLEC-2 hemITAM receptor with Src family kinases playing a critical role further downstream through the regulation of Syk and other effector proteins, providing a new paradigm in signaling by YXXL-containing receptors

ERP implementations and their impact upon management accountants

This paper considers the impact of ERP implementations upon the role of management accountants, upon management accounting in general, and upon business processes. It does so in the context of the perceived success of the ERP implementation. A postal questionnaire was circulated to almost 700 management accountants working in large UK-based organisations. It finds that under successful ERP implementations, management accountants have time for other, less mundane activities and their role becomes more enriching. In contrast, when the implementation is unsuccessful, the role of the management accountant increases: the ERP system deficiencies require increased activity on their part without any noticeable reduction in the tasks they traditionally perform