3,061 research outputs found
On the Bike Spreading Problem
A free-floating bike-sharing system (FFBSS) is a dockless rental system where an individual can borrow a bike and returns it anywhere, within the service area. To improve the rental service, available bikes should be distributed over the entire service area: a customer leaving from any position is then more likely to find a near bike and then to use the service. Moreover, spreading bikes among the entire service area increases urban spatial equity since the benefits of FFBSS are not a prerogative of just a few zones. For guaranteeing such distribution, the FFBSS operator can use vans to manually relocate bikes, but it incurs high economic and environmental costs. We propose a novel approach that exploits the existing bike flows generated by customers to distribute bikes. More specifically, by envisioning the problem as an Influence Maximization problem, we show that it is possible to position batches of bikes on a small number of zones, and then the daily use of FFBSS will efficiently spread these bikes on a large area. We show that detecting these zones is NP-complete, but there exists a simple and efficient 1-1/e approximation algorithm; our approach is then evaluated on a dataset of rides from the free-floating bike-sharing system of the city of Padova
Polynomial evaluation over finite fields: new algorithms and complexity bounds
An efficient evaluation method is described for polynomials in finite fields.
Its complexity is shown to be lower than that of standard techniques when the
degree of the polynomial is large enough. Applications to the syndrome
computation in the decoding of Reed-Solomon codes are highlighted.Comment: accepted for publication in Applicable Algebra in Engineering,
Communication and Computing. The final publication will be available at
springerlink.com. DOI: 10.1007/s00200-011-0160-
A soft sensor of cell concentration in a perfusion bioreactor via a digital twin
Please click Additional Files below to see the full abstract
Tradução da novela Der Tod des Kleinbürgers, de Franz Werfel, para o português
Franz Werfel was born in 1890 in Prague. His family belonged to the Jewish community of German Bohemia. A poet, storyteller and novelist, he was a member of the Prague group, a contemporary of Franz Kafka. He was editor of great German-speaking poets such as Georg Trakl. In the 1920s he married Alma Mahler and lived in Vienna until they realized how dangerous it had become to be Jewish in territories under the Nazis. They emigrated to the United States, where he became an American citizen in 1941. He died in 1945, at the age of 54, of a heart attack. Published in 1926, the novel "The Death of a Poor Man", is set in the period after the First War, a time of great demographic movement in the nations that originated from the Austro-Hungarian Empire, characterized by strong immigration of the Czech population of Germanic origin to Vienna. The rapid urban modernisation was not followed by the creation of jobs needed for the population. With the shattering of the Austro-Hungarian Empire the military lost their usefulness and prestige. Many had to be fired and they were lucky if they could receive a post as civil servants. Here is the translation of chapter 01 of the novel.Franz Werfel nasceu em 1890 em Praga. Sua família pertencia à comunidade judaica da Boêmia alemã. Poeta, contista e romancista, era membro do grupo de Praga, contemporâneo de Franz Kafka. Seu romance mais conhecido é Die vierzig Tage des Musa Dagh. Foi editor de grandes poetas em língua alemã tal como Georg Trakl. Na década de 1920 casa-se com Alma Mahler e vivem em Viena até perceberem como se tornara perigoso ser judeu em territórios sujeitos à Alemanha nazista. Emigram para os Estados Unidos, onde tornou-se cidadão norte-americano em 1941. Morreu em 1945, com 54 anos, de ataque cardíaco. Publicada em 1926, a novela “A morte do pequeno burguês”, está ambientada no período após a Primeira Guerra, época de grande movimento demográfico nas nações que se originam do Império Austro-Húngaro, caracterizada por uma forte imigração da população tcheca de origem germânica para Viena. A rápida modernização urbana não é acompanhada pela geração de empregos necessários para a população. Com o esfacelamento do império austro-húngaro os militares perdem a utilidade e o prestígio. Muitos tiveram de ser demitidos e se tivessem sorte receberiam um posto como funcionários públicos. Segue a tradução do capítulo 01 da novela
CONCESSÃO DE MICROCRÉDITO EM BANCOS DE INVESTIMENTO E DESENVOLVIMENTO NA AMÉRICA LATINA, COMO INSTRUMENTO DE CRESCIMENTO ECONÔMICO E DESENVOLVIMENTO HUMANO
RESUMOO objetivo deste artigo é analisar, por meio de dados oficiais, a concessão de empréstimos de microcrédito em bancos de desenvolvimento na América Latina, especificamente o Banco Compartamos do México e o Banco do Nordeste do Brasil S/A, da cidade de Fortaleza, Ceará. Cumpre salientar que se trata de empréstimo de baixo valor, destinado a pessoas vulneráveis com dificuldades de acesso ao crédito nas instituições financeiras. Inicialmente, apresentou-se a origem do empréstimo de microcrédito, a partir da ideia de Muhammad Yunus, em 1974, em Bangladesch, o qual emprestou do próprio bolso a quantia de U27 dollars to 42 artisans in order to buy bamboo straws and get rid of loan sharks. Subsequently, an analysis was made of the two largest microcredit concession in Latin America development banks: Banco Compartamos and Banco do Nordeste. This, with the Crediamigo program, which is recognized as the largest microcredit program in South America, serves around 16,000 people daily, with a portfolio of more than two million clients, which 67% are women. The other, reached the ranking of first place in Latin America by granting several modalities of loans. At the end, we discussed microcredit as an effective tool for economic growth and human development. We conclude that microcredit is the driving force behind employment, income and poverty. Through bibliographic theoretical and qualitative research, it was verified that microcredit loan is conditio sine qua non for just and solidary society realization. KEYWORDS: Microcredit; Latin America Development banks; Economic growth; Human development
CC-chemokine ligand 16 induces a novel maturation program in human immature monocyte-derived dendritic cells
Dendritic cells (DCs) are indispensable for initiation of primary T cell responses and a host's defense against infection. Many proinflammatory stimuli induce DCs to mature (mDCs), but little is known about the ability of chemokines to modulate their maturation. In the present study, we report that CCL16 is a potent maturation factor for monocyte-derived DCs (MoDCs) through differential use of its four receptors and an indirect regulator of Th cell differentiation. MoDCs induced to mature by CCL16 are characterized by increased expression of CD80 and CD86, MHC class II molecules, and ex novo expression of CD83 and CCR7. They produce many chemokines to attract monocytes and T cells and are also strong stimulators in activating allogeneic T cells to skew toward Th1 differentiation. Interestingly, they are still able to take up Ag and express chemokine receptors usually bound by inflammatory ligands and can be induced to migrate to different sites where they capture Ags. Our findings indicate that induction of MoDC maturation is an important property of CCL16 and suggest that chemokines may not only organize the migration of MoDCs, but also directly regulate their ability to prime T cell responses
Effects of environmental and physiological covariates on sex differences in unconditioned and conditioned anxiety and fear in a large sample of genetically heterogeneous (N/Nih-HS) rats
Physiological and environmental variables, or covariates, can account for an important portion of the variability observed in behavioural/physiological results from different laboratories even when using the same type of animals and phenotyping procedures. We present the results of a behavioural study with a sample of 1456 genetically heterogeneous N/Nih-HS rats, including males and females, which are part of a larger genome-wide fine-mapping QTL (Quantitative Trait Loci) study. N/Nih-HS rats have been derived from 8 inbred strains and provide very small distance between genetic recombinations, which makes them a unique tool for fine-mapping QTL studies. The behavioural test battery comprised the elevated zero-maze test for anxiety, novel-cage (open-field like) activity, two-way active avoidance acquisition (related to conditioned anxiety) and context-conditioned freezing (i.e. classically conditioned fear). Using factorial analyses of variance (ANOVAs) we aimed to analyse sex differences in anxiety and fear in this N/Nih-HS rat sample, as well as to assess the effects of (and interactions with) other independent factors, such as batch, season, coat colour and experimenter. Body weight was taken as a quantitative covariate and analysed by covariance analysis (ANCOVA). Obliquely-rotated factor analyses were also performed separately for each sex, in order to evaluate associations among the most relevant variables from each behavioural test and the common dimensions (i.e. factors) underlying the different behavioural responses. ANOVA analyses showed a consistent pattern of sex effects, with females showing less signs of anxiety and fear than males across all tests. There were also significant main effects of batch, season, colour and experimenter on almost all behavioural variables, as well as "sex × batch", "sex × season" and "sex × experimenter" interactions. Body weight showed significant effects in the ANCOVAs of most behavioural measures, but sex effects were still present in spite of (and after controlling for) these "body weight" effects. Factor analyses of relevant variables from each test showed a two-fold factor structure in both sexes, with the first factor mainly representing anxiety and conditioned fear in males, while in females the first factor was dominated by loadings of activity measures. Thus, besides showing consistent sex differences in anxiety-, fear- and activity-related responses in N/Nih-HS rats, the present study shows that females' behaviour is predominantly influenced by activity while males are more influenced by anxiety. Moreover, the results point out that, besides "sex" effects, physiological variables such as colour and body weight, and environmental factors as batch/season or "experimenter", have to be taken into account in both behavioural and quantitative genetic studies because of their demonstrated influences on phenotypic outcomes
VIALACTEA knowledge base homogenizing access to Milky Way data
The VIALACTEA project has a work package dedicated to "Tools and Infrastructure" and, inside it, a task for the "Database and Virtual Observatory Infrastructure". This task aims at providing an infrastructure to store all the resources needed by the, more purposely, scientific work packages of the project itself. This infrastructure includes a combination of: storage facilities, relational databases and web services on top of them, and has taken, as a whole, the name of VIALACTEA Knowledge Base (VLKB). This contribution illustrates the current status of this VLKB. It details the set of data resources put together; describes the database that allows data discovery through VO inspired metadata maintenance; illustrates the discovery, cutout and access services built on top of the former two for the users to exploit the data content
Vialactea Visual Analytics tool for Star Formation studies of the Galactic Plane
We present a visual analytics tool, based on the VisIVO suite, to exploit a
combination of all new-generation surveys of the Galactic Plane to study the
star formation process of the Milky Way. The tool has been developed within the
VIALACTEA project, founded by the 7th Framework Programme of the European
Union, that creates a common forum for the major new-generation surveys of the
Milky Way Galactic Plane from the near infrared to the radio, both in thermal
continuum and molecular lines. Massive volumes of data are produced by space
missions and ground-based facilities and the ability to collect and store them
is increasing at a higher pace than the ability to analyze them. This gap leads
to new challenges in the analysis pipeline to discover information contained in
the data. Visual analytics focuses on handling these massive, heterogeneous,
and dynamic volumes of information accessing the data previously processed by
data mining algorithms and advanced analysis techniques with highly interactive
visual interfaces offering scientists the opportunity for in-depth
understanding of massive, noisy, and high-dimensional data
- …