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51.
俄罗斯联邦高等教育包括大学教育(分为5年专家学历和4年本科学历加2年硕士学历,两种学历学制并存)和研究生(大学后)教育(分为3年副博士和3年博士两阶段)。高等教育实行双轨制,并积极与西方教育接轨。主要形式有全日制、夜校、函授、自考、网络和远程教育等,但主体是高校,特别是国家型高校及分校。奖学金额度相对较低,大学生通过非全日制方式完成高等教育较为盛行。近年随着俄罗斯人口出生率的下降,众多高校面临招生困境,很多高校将被关闭或重组。由于中俄两国的历史渊源关系以及良好的政治经济合作基础,未来中俄两国高等教育合作的前景广阔。  相似文献   
52.
The motivation for this paper was the introduction of novel short‐term models to trade the FTSE 100 and DAX 30 exchange‐traded funds (ETF) indices. There are major contributions in this paper which include the introduction of an input selection criterion when utilizing an expansive universe of inputs, a hybrid combination of partial swarm optimizer (PSO) with radial basis function (RBF) neural networks, the application of a PSO algorithm to a traditional autoregressive moving model (ARMA), the application of a PSO algorithm to a higher‐order neural network and, finally, the introduction of a multi‐objective algorithm to optimize statistical and trading performance when trading an index. All the machine learning‐based methodologies and the conventional models are adapted and optimized to model the index. A PSO algorithm is used to optimize the weights in a traditional RBF neural network, in a higher‐order neural network (HONN) and the AR and MA terms of an ARMA model. In terms of checking the statistical and empirical accuracy of the novel models, we benchmark them with a traditional HONN, with an ARMA, with a moving average convergence/divergence model (MACD) and with a naïve strategy. More specifically, the trading and statistical performance of all models is investigated in a forecast simulation of the FTSE 100 and DAX 30 ETF time series over the period January 2004 to December 2015 using the last 3 years for out‐of‐sample testing. Finally, the empirical and statistical results indicate that the PSO‐RBF model outperforms all other examined models in terms of trading accuracy and profitability, even with mixed inputs and with only autoregressive inputs. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
53.
M M Lo  D L Niehoff  M J Kuhar  S H Snyder 《Nature》1983,306(5938):57-60
A number of studies have suggested the existence of multiple benzodiazepine binding sites in the brain. We have recently reported the physical separation of two apparent benzodiazepine binding site subtypes, the pharmacological properties, and distribution in tissue sections of which correspond to the putative type I and type II sites. Benzodiazepine and gamma-aminobutyric acid (GABA) receptors have been shown to interact, and lesions of the GABAergic striatonigral pathway, which lead to GABA supersensitivity, both increase the numbers of GABA binding sites and enhance GABA-stimulated benzodiazepine binding. We demonstrate here that degeneration of striatonigral fibres increases the density of putative type I benzodiazepine binding sites in the substantia nigra and decreases the density of the putative type II sites. This suggests that type I sites that increase after denervation are postsynaptic, whereas the type II sites reduced by the lesion may be localized to axons or terminals of the striatonigral pathways.  相似文献   
54.
Myeloproliferative disorders are clonal haematopoietic stem cell malignancies characterized by independency or hypersensitivity of haematopoietic progenitors to numerous cytokines. The molecular basis of most myeloproliferative disorders is unknown. On the basis of the model of chronic myeloid leukaemia, it is expected that a constitutive tyrosine kinase activity could be at the origin of these diseases. Polycythaemia vera is an acquired myeloproliferative disorder, characterized by the presence of polycythaemia diversely associated with thrombocytosis, leukocytosis and splenomegaly. Polycythaemia vera progenitors are hypersensitive to erythropoietin and other cytokines. Here, we describe a clonal and recurrent mutation in the JH2 pseudo-kinase domain of the Janus kinase 2 (JAK2) gene in most (> 80%) polycythaemia vera patients. The mutation, a valine-to-phenylalanine substitution at amino acid position 617, leads to constitutive tyrosine phosphorylation activity that promotes cytokine hypersensitivity and induces erythrocytosis in a mouse model. As this mutation is also found in other myeloproliferative disorders, this unique mutation will permit a new molecular classification of these disorders and novel therapeutical approaches.  相似文献   
55.
本文研究了α-FeOOH微晶的热处理最后一个过程--Fe2O4→γ-Fe2O3这一氧化过程的工艺,考察了时间和反应温度对γ一Fe2O3磁粉性能的影响,确定了适宜的氧化工艺条件为;Fe3O4在180-200℃下通过空气氧化10-30min,并得到最佳性能产物组合为介于Fe3O4和γ-Fe2O3之间的固溶体。  相似文献   
56.
We investigated the mechanisms for glucocorticoid regulation of rat renal NaK-ATPase activity. Our findings suggest that the magnitudes of corticosterone-induced increases in 1 mRNA and 1 mRNA levels are similar in the kidney of the adult adrenalectomized rats. The results also suggest that corticosterone restores NaK-ATPase activity in adrenalectomized rats prior to any enhanced sodium delivery.  相似文献   
57.
ABSTRACT

The subgenus Mantidactylus is a group of frogs endemic to Madagascar, including the largest anuran species on the island. Although these frogs are common and widely distributed, their taxonomy remains unclear. Two species are currently recognised, M. grandidieri and M. guttulatus, with another available name, Rana pigra, considered to be a synonym of M. grandidieri. However, molecular studies have suggested the presence of several cryptic species within the group. Additionally, due to the lack of prominent morphological features, allocating the available names to evolutionary lineages has proven challenging. In the present study, we take a first step towards solving these problems by using fragments of the 16S mitochondrial gene and RAG1 nuclear gene from all over the range of the subgenus to describe its genetic diversity. We also use a newly designed target enrichment laboratory protocol to sequence three mitochondrial fragments from five name-holding museum specimens (as old as 120 years) in order to determine to which lineages the existing names should be applied. The study of the 16S mitochondrial gene revealed 7 geographically separated lineages, distinct enough to be considered candidate species. Out of the five museum specimens analysed, four successfully yielded DNA sequences and could be attributed to one of the aforementioned lineages. Therefore, the name Mantidactylus grandidieri should be applied to the populations from North-Eastern Madagascar, while M. guttulatus refers to populations from inland localities along the Eastern coast of the island. On the other hand, the holotype of Rana pigra did not yield enough genetic material to allow definitive identification. While our data were not sufficient to assess the status of the four lineages distributed along the Eastern coast, the populations from North-Western Madagascar were highly distinct on both the mitochondrial and nuclear markers. We thus describe them as a new species, M. radaka sp. nov.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:1EDDAF0D-FE37-490A-B09E-E136A0C5CB35  相似文献   
58.
In recent years,e-learning system has been adopted as a training tool in many firms,as it can help employees to complete training in a short time and at a low cost.Within this context,since 2003 the Industrial Development Bureau(IDB) of the Ministry of Economic Affairs(MOEA) in Taiwan sponsored more than 50 enterprises each year to help them implement customized e-learning systems. Past research on e-learning mostly focused on one criterion and adopted regression approach,such as examining the relationsh...  相似文献   
59.
L E Klein  C S Lo 《Experientia》1992,48(8):768-773
We investigated the mechanisms for glucocorticoid regulation of rat renal NaK-ATPase activity. Our findings suggest that the magnitudes of corticosterone-induced increases in alpha 1 mRNA and beta 1 mRNA levels are similar in the kidney of the adult adrenalectomized rats. The results also suggest that corticosterone restores NaK-ATPase activity in adrenalectomized rats prior to any enhanced sodium delivery.  相似文献   
60.
Stem cells reside in a specialized regulatory microenvironment or niche, where they receive appropriate support for maintaining self-renewal and multi-lineage differentiation capacity. The niche may also protect stem cells from environmental insults including cytotoxic chemotherapy and perhaps pathogenic immunity. The testis, hair follicle and placenta are all sites of residence for stem cells and are immune-suppressive environments, called immune-privileged sites, where multiple mechanisms cooperate to prevent immune attack, even enabling prolonged survival of foreign allografts without immunosuppression. We sought to determine if somatic stem-cell niches more broadly are immune-privileged sites by examining the haematopoietic stem/progenitor cell (HSPC) niche in the bone marrow, a site where immune reactivity exists. We observed persistence of HSPCs from allogeneic donor mice (allo-HSPCs) in non-irradiated recipient mice for 30?days without immunosuppression with the same survival frequency compared to syngeneic HSPCs. These HSPCs were lost after the depletion of FoxP3 regulatory T (T(reg)) cells. High-resolution in vivo imaging over time demonstrated marked co-localization of HSPCs with T(reg) cells that accumulated on the endosteal surface in the calvarial and trabecular bone marrow. T(reg) cells seem to participate in creating a localized zone where HSPCs reside and where T(reg) cells are necessary for allo-HSPC persistence. In addition to processes supporting stem-cell function, the niche will provide a relative sanctuary from immune attack.  相似文献   
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