Relaxation of quasi-stationary states in long range interacting systems and a classification of the range of pair interactions

International audienceSystems of particles interacting with long range interactions present generically "quasi-stationary states" (QSS), which are approximately time-independent out of equilibrium states. In this proceedings, we explore the generalization of the formation of such QSS and their relaxation from the much studied case of gravity to a generic pair interaction with the asymptotic form of the potential $v(r) \sim 1/r^\gamma$ with $\gamma > 0$ in $d$ dimensions. We compute analytic estimations of the relaxation time calculating the rate of two body collisionality in a virialized system approximated as homogeneous. We show that for $\gamma (d-1/2)$, it is dominated by small impact parameters. In addition, the lifetime of QSS increases with the number of particles if $\gamma d-1$. Using numerical simulations we confirm our analytic results. A corollary of our work gives a "dynamical" classification of interactions: the dynamical properties of the system depend on whether the pair force is integrable or not

Vlasov limit and discreteness effects in cosmological N-body simulations

We present the problematic of controlling the discreteness effects in cosmological N-body simulations. We describe a perturbative treatment which gives an approximation describing the evolution under self-gravity of a lattice perturbed from its equilibrium, which allows to trace the evolution of the fully discrete distribution until the time when particles approach one another ("shell-crossing"). Perturbed lattices are typical initial conditions for cosmological N-body simulations and thus we can describe precisely the early time evolution of these simulations. A quantitative comparison with fluid Lagrangian theory permits to study discreteness effects in the linear regime of the simulations. We show finally some work in progress about quantifying discreteness effects in the non-perturbative (highly non-linear) regime of cosmological N-body simulations by evolving different discretizations of the same continuous density field.Comment: 8 pages, proceedings (refereed) of "Vlasovia 2006", 2nd int'l workshop on the theory and applications of the Vlasov equation, Florence, September 2006. A more detailed report on recent progress may be found at arXiv:0805.135

Predictive Power of School Based Assessment Scores On Students’ Achievement In Junior Secondary Certificate Examination (JSCE) In English And Mathematics

The study investigated the predictive power of school based assessment scores on students’ achievement in Junior Secondary Certificate Examination (JSCE) in English and Mathematics. Two hypotheses tested at 0.05 level of significance guided the study. The study adopted an ex-post facto research design. A sample of 250 students were randomly drawn from ten (10) schools out of twenty (20) Junior secondary schools in Obio-Akpor Local Government Area of Rivers State. The instrument used for data collection was titled “Students Academic Record Inventory” (SARI). The instrument involves the students SBA score for JS1, JS2, JS3 and JSCE scores in English and Mathematics. The data generated were analyzed using multiple regression. The result revealed that the combination of the SBA scores significantly predicted students’ English and Mathematics achievement in JSCE, and there are relative effectiveness of SBA scores in students’ English and Mathematics achievement. Based on the findings of the study, recommendations were made including that school-based assessment should be encouraged and made compulsory for every secondary schools especially in core subjects which include English and Mathematics. Key words: Predictive power, school based, assessment, achievement

Conflitos em torno do Ministério da Educação: está em curso uma crise de hegemonia?

O presente texto tem como objetivo discutir se está em curso uma crise de hegemonia no Brasil, partindo dos conflitos para montagem da equipe a ocupar os cargos de primeiro, segundo e terceiro escalão no Ministério da Educação nos primeiros quatro meses do governo Bolsonaro. Para tanto, o texto está estruturado em quatro momentos: 1) na introdução, apresentamos o sentido conceitual sobre crise de hegemonia nos termos de Gramsci; 2) reconstituição dos conflitos no Ministério da Educação; 3) exposição e análise da Estratégia Democrático-Popular durante os governos petistas; 4) considerações finais, em que apresentamos a conclusão de que a crise de hegemonia pode ser vislumbrada como uma concreta perspectiva, a depender de fatores como a perda de apoio de demais frações da classe dominante e a irrupção da luta por parte da classe trabalhadora

Investment in innovation and its Influence on net sales: an analysis based on PINTEC data

The aim of this research is to analyze the influence of innovation investments on net sales from major national sectors. The data was collected from the free access to the Technological Innovation Research (PINTEC) database. To proceed the analysis, we collected the PINTEC data from the years 2000, 2003, 2005, 2008 and 2011, consolidating them in a specific way. The analysis were developed through regressions of panel data with fixed effects, according to Hausman test, and the definition of large scale sectors was based on the median of net sales. The results suggest that, on average, for the large scale sectors the acquisition of machinery & equipment and industrial projects & other technical improvements are statistically relevant variables to increase the net sales.

Trophic-mediated pelagic habitat structuring and partitioning by sympatric elasmobranchs

Funding provided by the TRIATLAS project through the European Union’s Horizon 2020 Research and Innovation Programme (grant No. 817578), the Conselho Nacional de Desenvolvimento Cientı́fico e Tecnológico - CNPq (478070/2008-0, 482557/2011-7), the Fundação Grupo Boticário (0760/2007.2), the Save Our Seas Foundation (66/2008), and the Fundação para a Ciência e Tecnologia – FCT (UIDB/04292/2020; UIDP/04292/2020), is deeply acknowledged. Scholarships granted by the FACEPE foundation to NPAB and by CNPq to BCLM (140567/2012-7) are also acknowledged. We acknowledge the Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio), the Brazilian Navy (SECIRM) and the Conselho Nacional de Desenvolvimento Cientı́fico e Tecnológico (CNPq) through the Pró-Arquipélago Program (557183/2009-0; 562062/20102-6; 405460/2012-0; 442884/2015-0) for providing precious logistic support.Pelagic elasmobranchs are key elements of oceanic ecosystems and must be preserved if marine trophic networks are to be kept in balance. Yet, they face intense fishing pressure that has been threatening their populations worldwide. Ensuring proper conservation management of these taxa depends on a better understanding of the strategies they use to explore the pelagic realm and their contributions to trophic web structuring across the ocean column. This study aimed at examining relationships between vertical habitat use and trophic attributes among six sympatric pelagic elasmobranchs using satellite transmitting tags in the western equatorial South Atlantic Ocean. The vertical movements of 35 elasmobranch individuals were tracked during an overall total of 1911 days. Clear relationships between species’ feeding habits, maximum diving depths, and proportion of time spent either in epipelagic or in surface waters were evidenced by Bayesian generalized linear mixed models and multivariate analysis. Filter-feeders made most use of deep waters from the mesopelagic and bathypelagic and shifted their diving depths in phase with diel vertical migrations of the deep scattering layer, i.e., shallower during the night and deeper during the day. Specialists exhibited distinct diving patterns in epipelagic and mesopelagic waters across the diel period which are potentially indicative of habitat partitioning, whereas generalists were more surface-oriented but also explored deeper waters compared to specialists. The trophic level also seemed to influence elasmobranch maximum diving depths, which tended to become shallower as species’ trophic level increased. These results corroborate previous evidence of widespread vertical habitat partitioning among sympatric pelagic predators and depict a trophicmediated structuring of the pelagic environment where top-down control may be exerted at different depths by distinct species. Further research is yet required to understand the role of elasmobranch vertical movements in structuring pelagic habitats as well as to guide ecosystem-based fisheries management aimed at reducing species susceptibility to fishing gear and at preserving the structure and functionality of marine trophic networks.info:eu-repo/semantics/publishedVersio

Absence of spontaneous magnetic order at non-zero temperature in one- and two-dimensional Heisenberg and XY systems with long-range interactions

The Mermin-Wagner theorem is strengthened so as to rule out magnetic long-range order at T>0 in one- or two-dimensional Heisenberg and XY systems with long-range interactions decreasing as R^{-alpha} with a sufficiently large exponent alpha. For oscillatory interactions, ferromagnetic long-range order at T>0 is ruled out if alpha >= 1 (D=1) or alpha > 5/2 (D=2). For systems with monotonically decreasing interactions ferro- or antiferromagnetic long-range order at T>0 is ruled out if alpha >= 2D.Comment: RevTeX, 4 pages. Further (p)reprints available from http://www.mpi-halle.de/~theory ; v2: revised versio

PT X PSDB: A ATUALIZAÇÃO DO EMBATE POLÍTICO NA ELEIÇÃO PRESIDENCIAL DE 2014

Partido da Social Democracia Brasileira (PSDB) e Partido dos Trabalhadores polarizam a disputa presidencial há 20 anos (PT). Entretanto, verifica-se uma tendência progressiva de crescimento de candidaturas de terceira via. Utilizando dados de surveys dos Estudos Eleitorais Brasileiros (ESEB), este trabalho examina como os sujeitos que não têm votado nas candidaturas do PT e do PSDB se posicionam sobre a política brasileira, e observa o comportamento político desses dois partidos, dentro das propagandas partidárias de  2014. Busca-se responder: quais são as opiniões demonstradas, entre 2002 e 2010, pelos eleitores das candidaturas de terceira via nas eleições nacionais? Como a disputa política, no espaço do horário eleitoral, contribuiu para a permanência da polarização PT x PSDB na eleição presidencial de 2014? Os eleitores de terceira via apresentaram, ainda que com queda em 2006, uma elevação da satisfação com a democracia, e da identificação e satisfação com partidos; maior rejeição ao PSDB do que ao PT. Em 2014, os partidos conseguiram atualizar o embate entre eles, construindo a ideia de que Marina podia ser relacionada a ambos e que a mudança simbolizada por ela era insegura

Quantifying the legacy of the Chinese Neolithic on the maternal genetic heritage of Taiwan and Island Southeast Asia

There has been a long-standing debate concerning the extent to which the spread of Neolithic ceramics and Malay-Polynesian languages in Island Southeast Asia (ISEA) were coupled to an agriculturally driven demic dispersal out of Taiwan 4000 years ago (4 ka). We previously addressed this question using founder analysis of mitochondrial DNA (mtDNA) control-region sequences to identify major lineage clusters most likely to have dispersed from Taiwan into ISEA, proposing that the dispersal had a relatively minor impact on the extant genetic structure of ISEA, and that the role of agriculture in the expansion of the Austronesian languages was therefore likely to have been correspondingly minor. Here we test these conclusions by sequencing whole mtDNAs from across Taiwan and ISEA, using their higher chronological precision to resolve the overall proportion that participated in the “out-of-Taiwan” mid-Holocene dispersal as opposed to earlier, postglacial expansions in the Early Holocene. We show that, in total, about 20 % of mtDNA lineages in the modern ISEA pool result from the “out-of-Taiwan” dispersal, with most of the remainder signifying earlier processes, mainly due to sea-level rises after the Last Glacial Maximum. Notably, we show that every one of these founder clusters previously entered Taiwan from China, 6–7 ka, where rice-farming originated, and remained distinct from the indigenous Taiwanese population until after the subsequent dispersal into ISEA

Naturalized Breeds in Brazil: Reports on the Origin and Genetic Diversity of the Pantaneiro Sheep

Brazil has several breeds of sheep, including animals that developed from breeds brought by settlers soon after their discovery. Over the years, these animals were under the process of natural selection, resulting in breeds that are considered naturalized. The Pantaneiro sheep shows rusticity and ability of adaptation to tropical climate regions and tolerance or resistance to disease and parasites. Molecular tools have marked the discovery of the origin and domestication processes of a wide variety of species, using both nuclear and mitochondrial molecular markers. These tools have aided in the understanding of evolutionary relationships, taxonomies, and demographics of various species and provided support to identify the most important areas for conservation programs, in addition to assisting in the analysis of genetic diversity in domestic, wildlife and endangered species. Researches using these tools show the importance of exploiting the potential of the genetic diversity found in locally adapted livestock. So far, a few studies were performed to observe that Pantaneiro sheep served as maternal basis for the origin of other breeds reared. Moreover, it is possible to suggest an European origin for the sheep populations studied; therefore, more studies using more markers are needed, so that it is possible to prove their origin