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1.
The growth of Brazilian scientific production in recent years is remarkable, which motivates an investigation on the factors, inside and outside the country, that helped shape this wealthy research environment. This article provides a thorough analysis of the education of researchers that constitute the main Brazilian research groups, using data on about 6,000 researchers involved in the country’s National Institutes of Science and Technology (INCT) initiative. Data on the steps taken by each researcher in her education, from the bachelor’s degree to doctorate, including a possible postdoctoral experience, and employment, are extracted from an official curriculum vitae repository. The location and the time at which each career step occurred define spatiotemporal career trajectories. We then analyze such trajectories considering additional data, including the area of knowledge of the INCTs to which each researcher is associated. We found an increasing prevalence of Brazilian institutions in the education of Brazilian scientists, as the number of doctorates earned abroad is decreasing over time. Postdoctoral stages, on the other hand, often take place in Europe or in the United States. Taking an international postdoctoral position after a full education in Brazil suggests a drive towards seeking higher-level exchange and cooperation with foreign groups in a more advanced career stage. Results also show that Brazilian researchers tend to seek employment in regions that are close to the institutions at which they received their bachelor’s degrees, suggesting low mobility within the country. This study can be instrumental in defining public policies for correcting distortions, and can help other developing countries that aim to improve their national science systems.  相似文献   

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The paper describes one of the central areas of research of Professor Natal’ya N. Traugott, a famous Russian neurophysiologist. In particular, Prof. Traugott identified the general neurophysiological mechanisms responsible for speech disorders in children with alalia and in adults with aphasia caused by focal brain lesions. Physiological experiments showed that both sensory alalia in children and sensory aphasia in adults are associated with the deficiency of auditory analyzer; such deficiency leads to disorders in the formation of conditional reactions to sounds and sound complexes. Moreover, a general development pattern was identified in the ontogeny of interaction of signal systems and in the degradation of such interaction caused by the lesions of particular analyzers. This finding of Prof. Traugott is very important in both theory of cerebral speech mechanisms and speech therapy practices aimed at speech system development and rehabilitation following cerebral dysfunctions.  相似文献   

3.
The early Eocene of the southern Bighorn Basin, Wyoming, is notable for its nearly continuous record of mammalian fossils. Microsyopinae (?Primates) is one of several lineages that shows evidence of evolutionary change associated with an interval referred to as Biohorizon A. Arctodontomys wilsoni is replaced by a larger species, Arctodontomys nuptus, during the biohorizon interval in what is likely an immigration/emigration or immigration/local extinction event. The latter is then superseded by Microsyops angustidens after the end of the Biohorizon A interval. Although this pattern has been understood for some time, denser sampling has led to the identification of a specimen intermediate in morphology between A. nuptus and M. angustidens, located stratigraphically as the latter is appearing. Because specimens of A. nuptus have been recovered approximately 60 m above the appearance of M. angustidens, it is clear that A. nuptus did not suffer pseudoextinction. Instead, evidence suggests that M. angustidens branched off from a population of A. nuptus, but the latter species persisted. This represents possible evidence of cladogenesis, which has rarely been directly documented in the fossil record. The improved understanding of both evolutionary transitions with better sampling highlights the problem of interpreting gaps in the fossil record as punctuations.  相似文献   

4.
Animal stereotypies have long been used in the study of obsessive–compulsive disorder (OCD) in humans. These studies have led to the understanding of some of the molecular pathways in the disorder and the use of selective serotonin reuptake inhibitors and myo-inositol in the treatment of these conditions. If animal models, especially nonhuman primate models, were used to study human disorders and if the resulting treatments were successful, then conversely one should be able to treat nonhuman primate stereotypies with similar methods. We here summarize animal models of OCD (including nonhuman primate models) and human OCD treatments, and using successful human treatment by myo-inositol as models, recommend the use of myo-inositol in good captive management practice and the treatment of nonhuman primate stereotypies. We believe that this would be particularly useful in the treatment of stereotypies in nonhuman primates because they are physiologically so similar to humans.  相似文献   

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This article discusses potential Ukrainian rights of passage through Kerch Strait against the background of restrictions on passage imposed by Russia since the annexation of Crimea, taking into account the ongoing arbitral proceedings under Annex VII of the UN Convention on the Law of the Sea. The article addresses first the question of the status of Kerch Strait and the Sea of Azov under the international law of the sea. In a second step, the article deals with the issue of potential Ukrainian passage rights through Kerch Strait based on the legal status discussed in the first section as well as relevant bilateral treaties between Ukraine and Russia.  相似文献   

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Background

Guatemala is a multiethnic and multilingual country located in Central America. The main population groups separate ‘Ladinos’ (mixed Native American-African-Spanish), and Native indigenous people of Maya descent. Among the present-day Guatemalan Maya, there are more than 20 different ethnic groups separated by different languages and cultures. Genetic variation of these communities still remains largely unexplored. The principal aim of this study is to explore the genetic variability of the Maya and ‘Ladinos’ from Guatemala by means of uniparental and ancestry informative markers (AIMs).

Results

Analyses of uniparental genetic markers indicate that Maya have a dominant Native American ancestry (mitochondrial DNA [mtDNA]: 100%; Y-chromosome: 94%). ‘Ladino’, however, show a clear gender-bias as indicated by the large European ancestry observed in the Y-chromosome (75%) compared to the mtDNA (0%). Autosomal polymorphisms (AIMs) also mirror this marked gender-bias: (i) Native American ancestry: 92% for the Maya vs. 55% for the ‘Ladino’, and (ii) European ancestry: 8% for the Maya vs. 41% for the ‘Ladino’. In addition, the impact of the Trans-Atlantic slave trade on the present-day Guatemalan population is very low (and only occurs in the ‘Ladino’; mtDNA: 9%; AIMs: 4%), in part mirroring the fact that Guatemala has a predominant orientation to the Pacific Ocean instead of a Caribbean one. Sequencing of entire Guatemalan mitogenomes has led to improved Native American phylogeny via the addition of new haplogroups that are mainly observed in Mesoamerica and/or the North of South America.

Conclusions

The data reveal the existence of a fluid gene flow in the Mesoamerican area and a predominant unidirectional flow towards South America, most likely occurring during the Pre-Classic (1800 BC-200 AD) and the Classic (200–1000 AD) Eras of the Mesoamerican chronology, coinciding with development of the most distinctive and advanced Mesoamerican civilization, the Maya. Phylogenetic features of mtDNA data also suggest a demographic scenario that is compatible with moderate local endogamy and isolation in the Maya combined with episodes of gene exchange between ethnic groups, suggesting an ethno-genesis in the Guatemalan Maya that is recent and supported on a cultural rather than a biological basis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1339-1) contains supplementary material, which is available to authorized users.  相似文献   

8.
The characteristics of the formation of the superoxide radical anion (\(\rm{O}_2^{\bullet-}\)) and hydrogen peroxide by xanthine oxidases isolated from microorganisms and from cow’s milk were investigated. The increase in pH led to an increase in the rate of xanthine oxidation with oxygen by both xanthine oxidases. The functioning of xanthine oxidase from milk along with the two-electron reduction of O2 to H2O2 carries through the one-electron reduction of O2 to \(\rm{O}_2^{\bullet-}\), and the rate and the fraction of generation of \(\rm{O}_2^{\bullet-}\) increased with increasing pH. Under operation of the microbial xanthine oxidase, the \(\rm{O}_2^{\bullet-}\) radical was not detected in the medium. The results suggest a difference in the operation of active centers of enzyme from different sources.  相似文献   

9.
Vegetation with Cardaminopsis petraea was sampled by phytosociological relevés at almost all the known Czech sites, and characterized by indicator values, influence of potential direct solar irradiation, and bedrock type with the aid of multivariate methods. It has been declared that C. petraea prefers open natural or seminatural drier to mesophilous habitats without some preference to the bedrock. It occupies habitats with various slopes, but it prefers more extreme slants and northerly exposed slopes. The classification and ordination methods showed clear distinction between Moravian and Bohemian habitats. Apart from other types, in Bohemia this species occurs uniquely in acidophilous rock communities, whereas in Moravia it grows uniquely within calcareous grasslands. Relictness of the species was discussed in relation to the specific site conditions (light supply, disturbance regime, and geographical isolation) and to the occurrence of other rare taxa and habitats. Occurrence on some man-made habitats was also observed.  相似文献   

10.
Ibragimova  D. V.  Lyapkov  S. M. 《Biology Bulletin》2018,45(8):831-838
Biology Bulletin - We analyzed the variations in the demographic and morphological characteristics of mature Rana arvalis individuals from natural and transformed habitats near Surgut. Female frogs...  相似文献   

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Two highly conserved structural motifs observed in members of the EF-hand family of calcium binding proteins. The motifs provide a supporting scaffold for the Ca2+ binding loops and contribute to the hydrophobic core of the EF-hand domain. Each structural motif represents a cluster of three amino acids called cluster I (‘black’ cluster) and cluster II (‘grey’ cluster). Cluster I is more conserved and mostly incorporates aromatic amino acids. In contrast, cluster II is noticeably less conserved and includes a mix of aromatic, hydrophobic, and polar amino acids of different sizes. In the human calcium binding S100 P protein, these ‘black’ and ‘gray’ clusters include residues F15, F71, and F74 and L33, L58, and K30, respectively. To evaluate the effects of these clusters on structure and functionality of human S100 P, we have performed Ala scanning. The resulting mutants were studied by a multiparametric approach that included circular dichroism, scanning calorimetry, dynamic light scattering, chemical crosslinking, and fluorescent probes. Spectrofluorimetric Ca2+-titration of wild type S100 P showed that S100 P dimer has 1–2 strong calcium binding sites (K1 = 4 × 106 M−1) and two cooperative low affinity (K2 = 4 × 104 M−1) binding sites. Similarly, the S100 P mutants possess two types of calcium binding sites. This analysis revealed that the alanine substitutions in the clusters I and II caused comparable changes in the S100 P functional properties. However, analysis of heat- or GuHCl-induced unfolding of these proteins showed that the alanine substitutions in the cluster I caused notably more pronounced decrease in the protein stability compared to the changes caused by alanine substitutions in the cluster II. Opposite to literature data, the F15 A substitution did not cause the S100 P dimer dissociation, indicating that F15 is not crucial for dimer stability. Overall, similar to parvalbumins, the S100 P cluster I is more important for protein conformational stability than the cluster II.  相似文献   

14.
Trypanosome infections were sought in 46 non-human primates captured principally in Amazonian Brazil. Twenty-two (47.8%) were infected with four Trypanosoma species: T. cruzi, T. minasense, T. devei and T. rangeli. These preliminary results confirmed the high prevalence and diversity of natural infections with trypanosomes in primates from Brazilian Amazon and were the first formal record of simian infections with trypanosomes in the State of Acre. The presence of T. cruzi-like and T. rangeli-like parasites are recorded in four new hosts.  相似文献   

15.
Summary The microorganisms responsible for the fermentation of iru, obtained from local producers, were isolated and identified. Only bacteria were involved in the fermentation; the species areMicrococcus luteus, Staphylococcus aureus, Bacillus subtilis, Lactobacillus plantarum, Citrobacter freundii, Lactobacillus salivarius andStreptococcus pyogenes. Microbial population, temperature, pH and moisture content increased with increase in period of fermentation. A progressive in titratable acidity accompanied the fermentation.
Resumen Se aislaron e identificaron los microorganismos responsables de la fermentación de iru obtenido de productores locales. En el proceso de fermentación unicamente estaban implicadas bacterias que se identificaron como:Micrococcus luteus, Staphylococcus aureus, Bacillus subtilis, Lactobacillus plantarum, Citrobacter freundii, Lactobacillus salivarius yStreptococcus pyogenes. La población microbiana, la temperatura, el pH y el contenido en humedad se incrementaron al aumentar el periodo de fermentación. Se observó un decremento progresivo del título de acidez a lo largo de la fermentación.

Résumé Les microorganismes responsables de la fermentation des iru obtenus de producteurs locaux ont été isolés et identifiés. Seules des bactéries sont impliquées dans la fermentation. Les espèces sontMicrococcus luteus, Staphylococcus aureus, Bacillus subtilis, Lactobacillus plantarum, Citrobacter freundii, Lactobacillus salivarius etStreptococcus pyogenes. La population microbienne, la température, le pH et la teneur en eau agumentent avec l'augmentation du temps de fermentation. Une baisse progressive de l'acidité titrable accompagne la fermentation.
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DetectionandAnalysisofanEstrous-associatedOviductalGlycoproteinDNAFragmentfromPrimatesbyPCR¥CHENQing-xuan(陈清轩);ClaytonE.Walto...  相似文献   

18.
Fossil primates have been known from the late Miocene locality of Rudabánya since 1965. Numerous campaigns of collecting, sampling and excavation have been carried out since that time by several teams of researchers, but the sample of primates has never been fully catalogued and published. Here we provide a comprehensive list of all primate specimens from Rudabánya with provenience data and allocation to individuals. At the main locality of R II 16 individuals are attributed to Anapithecus and nine to Dryopithecus, based on dental remains. Anapithecus comes mostly from a layer of gray to black marl and Dryopithecus is found mostly in a less consolidated overlying black mud. However, both taxa are found in both layers. Anapithecus is represented by larger proportions of juveniles and females, and Dryopithecus by more adult and subadult males. Both species are represented primarily by dental remains, but those of Dryopithecus are more commonly associated with mandibles and maxillae, while in Anapithecus most individuals are represented by associated dentitions. Dryopithecus is better represented by postcrania other than phalanges. Anapithecus age and sex frequency distributions are more typical of those of carnivore and chimpanzee prey assemblages than Dryopithecus.  相似文献   

19.
A new genus,Siemensichthys, from the Upper Jurassic of southern Germany is described. The new genus includes two species,S. macrocephalus (Agassiz) which was formerly in the genusPholidophorus, andS. siemensi n. sp. The two species share synapomorphies such as only one supramaxillary bone covering the dorsal margin of the maxilla. Both species are described, and their phylogenetic position is analyzed. The phylogenetic analyses, based on 27 taxa and 141 characters, show thatAnkylophorus from the Kimmeridgian of Cerin,Siemensichthys andEurycormus from the Solnhofen Lithographic Limestone of Bavaria, form a monophyletic group. The new extinct clade (preliminarily identified as theSiemensichthys- group) is proposed as the sister-group ofPholidophorus s. str. plus more advanced teleosts. This sister-group relationship is supported by eight characters (e.g., supraoccipital bone extending forward in the roof of the otic region; articular bone fused with both the angular and retroarticular; presence of an elongated posteroventral process of quadrate; presence of dorsal processes at the base of the innermost caudal rays of upper lobe; mobile premaxillary bone). Comparisons with species ofPholidophorus s. str. provide a new understanding of the genusPholidophorus. At least four synapomorphies are proposed to support the monophyly ofPholidophorus. As a consequence of this new interpretation, the European Late Jurassic species previously assigned to the Pholidophoridae and to the genusPholidophorus (e.g., ‘Ph.’armatus, ‘Ph.’ falcifer, ‘Ph.’ micronyx, ‘Ph.’ microps) should be reexamined because they do not belong to the family nor to the genus. The order PholidophoriformesBerg is not a monophyletic group as currently constructed. Therefore, all so-called pholidophoriforms are in need of revision.  相似文献   

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