996 resultados para Sobolev-type orthogonal polynomials


Relevância:

20.00% 20.00%

Publicador:

Resumo:

ABSTRACT In order to solve the affinities of the species of Isotes Weise, 1922, a detailed morphological comparative study was carried out based on type-species of Isotes and its junior synonym,Synbrotica Bechyné, 1956. Isotes tetraspilota (Baly, 1865) and Isotes borrei (Baly, 1889) had their morphology of mouthparts, endosternites, wings and both male and female genitalia compared by the first time. A new synonymy is established between Isotes borrei (Baly, 1889) and Isotes crucigera (Weise, 1916) syn. nov. based on external and genitalia morphology. New structures for Section Diabroticites Chapuis, 1875 are presented and discussed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

It is known that, in a locally presentable category, localization exists with respect to every set of morphisms, while the statement that localization with respect to every (possibly proper) class of morphisms exists in locally presentable categories is equivalent to a large-cardinal axiom from set theory. One proves similarly, on one hand, that homotopy localization exists with respect to sets of maps in every cofibrantly generated, left proper, simplicial model category M whose underlying category is locally presentable. On the other hand, as we show in this article, the existence of localization with respect to possibly proper classes of maps in a model category M satisfying the above assumptions is implied by a large-cardinal axiom called Vopënka's principle, although we do not know if the reverse implication holds. We also show that, under the same assumptions on M, every endofunctor of M that is idempotent up to homotopy is equivalent to localization with respect to some class S of maps, and if Vopënka's principle holds then S can be chosen to be a set. There are examples showing that the latter need not be true if M is not cofibrantly generated. The above assumptions on M are satisfied by simplicial sets and symmetric spectra over simplicial sets, among many other model categories.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

1. Pesquisamos a atividade antibacteriana em 14 amostras de Aspergillus niger da National Collection of Type Cultures. 2. Em meio de Raulin e Mosseray, sete amostras apresentaram atividade total, nunca superior a 1:10, contra Staphylococcus aureus nº 553, sendo que as amostras 1.161 e 2.390 permaneceram ativas por mais de 40 dias. 3. A utilização do meio de Czapek-Dox com 5% de "corn-steep" não melhorou os resultados obtidos com o meio de Raulin e Mosseray. 4. No meio de levedo peptonado, todas as amostras apresentaram-se inativas.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Maximal-length binary sequences have been known for a long time. They have many interesting properties, one of them is that when taken in blocks of n consecutive positions they form 2ⁿ-1 different codes in a closed circular sequence. This property can be used for measuring absolute angular positions as the circle can be divided in as many parts as different codes can be retrieved. This paper describes how can a closed binary sequence with arbitrary length be effectively designed with the minimal possible block-length, using linear feedback shift registers (LFSR). Such sequences can be used for measuring a specified exact number of angular positions, using the minimal possible number of sensors that linear methods allow.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

R.P. Boas has found necessary and sufficient conditions of belonging of function to Lipschitz class. From his findings it turned out, that the conditions on sine and cosine coefficients for belonging of function to Lip α(0 & α & 1) are the same, but for Lip 1 are different. Later his results were generalized by many authors in the viewpoint of generalization of condition on the majorant of modulus of continuity. The aim of this paper is to obtain Boas-type theorems for generalized Lipschitz classes. To define generalized Lipschitz classes we use the concept of modulus of smoothness of fractional order.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

To a finite graph there corresponds a free partially commutative group: with the given graph as commutation graph. In this paper we construct an orthogonality theory for graphs and their corresponding free partially commutative groups. The theory developed here provides tools for the study of the structure of partially commutative groups, their universal theory and automorphism groups. In particular the theory is applied in this paper to the centraliser lattice of such groups.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Creptotrema creptotrema Travassos, Artigas & Pereira, 1928, a digenetic trematode parasite of Leporinus elongatus, is redescribed from the type-material with additional morphological data and original figures.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

MicroRNAs (miRNAs) have been shown to play important roles in both brain development and the regulation of adult neural cell functions. However, a systematic analysis of brain miRNA functions has been hindered by a lack of comprehensive information regarding the distribution of miRNAs in neuronal versus glial cells. To address this issue, we performed microarray analyses of miRNA expression in the four principal cell types of the CNS (neurons, astrocytes, oligodendrocytes, and microglia) using primary cultures from postnatal d 1 rat cortex. These analyses revealed that neural miRNA expression is highly cell-type specific, with 116 of the 351 miRNAs examined being differentially expressed fivefold or more across the four cell types. We also demonstrate that individual neuron-enriched or neuron-diminished RNAs had a significant impact on the specification of neuronal phenotype: overexpression of the neuron-enriched miRNAs miR-376a and miR-434 increased the differentiation of neural stem cells into neurons, whereas the opposite effect was observed for the glia-enriched miRNAs miR-223, miR-146a, miR-19, and miR-32. In addition, glia-enriched miRNAs were shown to inhibit aberrant glial expression of neuronal proteins and phenotypes, as exemplified by miR-146a, which inhibited neuroligin 1-dependent synaptogenesis. This study identifies new nervous system functions of specific miRNAs, reveals the global extent to which the brain may use differential miRNA expression to regulate neural cell-type-specific phenotypes, and provides an important data resource that defines the compartmentalization of brain miRNAs across different cell types.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background. Accurate quantification of the prevalence of human immunodeficiency virus type 1 (HIV-1) drug resistance in patients who are receiving antiretroviral therapy (ART) is difficult, and results from previous studies vary. We attempted to assess the prevalence and dynamics of resistance in a highly representative patient cohort from Switzerland. Methods. On the basis of genotypic resistance test results and clinical data, we grouped patients according to their risk of harboring resistant viruses. Estimates of resistance prevalence were calculated on the basis of either the proportion of individuals with a virologic failure or confirmed drug resistance (lower estimate) or the frequency-weighted average of risk group-specific probabilities for the presence of drug resistance mutations (upper estimate). Results. Lower and upper estimates of drug resistance prevalence in 8064 ART-exposed patients were 50% and 57% in 1999 and 37% and 45% in 2007, respectively. This decrease was driven by 2 mechanisms: loss to follow-up or death of high-risk patients exposed to mono- or dual-nucleoside reverse-transcriptase inhibitor therapy (lower estimates range from 72% to 75%) and continued enrollment of low-risk patients who were taking combination ART containing boosted protease inhibitors or nonnucleoside reverse-transcriptase inhibitors as first-line therapy (lower estimates range from 7% to 12%). A subset of 4184 participants (52%) had 1 study visit per year during 2002-2007. In this subset, lower and upper estimates increased from 45% to 49% and from 52% to 55%, respectively. Yearly increases in prevalence were becoming smaller in later years. Conclusions. Contrary to earlier predictions, in situations of free access to drugs, close monitoring, and rapid introduction of new potent therapies, the emergence of drug-resistant viruses can be minimized at the population level. Moreover, this study demonstrates the necessity of interpreting time trends in the context of evolving cohort populations.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

To specifically induce a mucosal antibody response to purified human papillomavirus type 16 (HPV16) virus-like particles (VLP), we immunized female BALB/c mice orally, intranasally, and/or parenterally and evaluated cholera toxin (CT) as a mucosal adjuvant. Anti-HPV16 VLP immunoglobulin G (IgG) and IgA titers in serum, saliva, and genital secretions were measured by enzyme-linked immunosorbent assay (ELISA). Systemic immunizations alone induced HPV16 VLP-specific IgG in serum and, to a lesser extent, in genital secretions but no secretory IgA. Oral immunization, even in the presence of CT, was inefficient. However, three nasal immunizations with 5 microgram of VLP given at weekly intervals to anesthetized mice induced high (>10(4)) and long-lasting (>15 weeks) titers of anti-HPV16 VLP antibodies in all samples, including IgA and IgG in saliva and genital secretions. CT enhanced the VLP-specific antibody response 10-fold in serum and to a lesser extent in saliva and genital secretions. Nasal immunization of conscious mice compared to anesthetized mice was inefficient and correlated with the absence of uptake of a marker into the lung. However, a 1-microgram VLP systemic priming followed by two 5-microgram VLP intranasal boosts in conscious mice induced both HPV16 VLP-specific IgG and IgA in secretions, although the titers were lower than in anesthetized mice given three intranasal immunizations. Antibodies in serum, saliva, and genital secretions of immunized mice were strongly neutralizing in vitro (50% neutralization with ELISA titers of 65 to 125). The mucosal and systemic/mucosal HPV16 VLP immunization protocols that induced significant titers of neutralizing IgG and secretory IgA in mucosal secretions in mice may be relevant to genital HPV VLP-based human vaccine trials.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We show that the classifying category C(T)of a dependent type theory T with axioms for identity types admits a nontrivial weak factorisation system. After characterising this weak factorisation system explicitly, we relate it to the homotopy theory of groupoids.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A dengue outbreak started in March, 1986 in Rio de Janeiro and spread very rapidly to other parts of the country. The great majority of cases presented classical dengue fever but there was one fatal case, confirmed by virus isolation. Dengue type 1 strains were isolated from patients and vectors (Aedes aegypti) in the area by cultivation in A. albopictus C6/36 cell line. The cytopathic effect (CPE) was studied by electron microscopy. An IgM capture test (MAC-ELISA) was applied with clear and reproducible results for diagnosis and evaluation of virus circulation; IgM antibodies appeared soon after start of clinical disease, and persisted for about 90 days in most patients. The test was type-specific in about 50% of the patients but high levels of heterologous response for type 3 were observed. An overall isolation rate of 46,8% (813 virus strains out of 1734 specimens) was recorded. The IgM test increased the number of confirmed cases to 58,2% (1479 out of 2451 suspected cases). The importance of laboratory diagnosis in all regions where the vectors are present is emphasized.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A 3D in vitro model of rat organotypic brain cell cultures in aggregates was used to investigate neurotoxicity mechanisms in glutaric aciduria type I (GA-I). 1 mM glutarate (GA) or 3-hydroxyglutarate (3OHGA) were repeatedly added to the culture media at two different time points. In cultures treated with 3OHGA, we observed an increase in lactate in the medium, pointing to a possible inhibition of Krebs cycle and respiratory chain. We further observed that 3OHGA and to a lesser extend GA induced an increase in ammonia production with concomitant decrease of glutamine concentrations, which may suggest an inhibition of the astrocytic enzyme glutamine synthetase. These previously unreported findings may uncover a pathogenic mechanism in this disease which has deleterious effects on early stages of brain development. By immunohistochemistry we showed that 3OHGA increased non-apoptotic cell death. On the cellular level, 3OHGA and to a lesser extend GA led to cell swelling and loss of astrocytic fibers whereas a loss of oligodendrocytes was only observed for 3OHGA. We conclude that 3OHGAwas the most toxic metabolite in our model for GA-I. 3OHGA induced deleterious effects on glial cells, an increase of ammonia production, and resulted in accentuated cell death of non-apoptotic origin.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

T-type Ca2+ channels (T channels) underlie rhythmic burst discharges during neuronal oscillations that are typical during sleep. However, the Ca2+-dependent effectors that are selectively regulated by T currents remain unknown. We found that, in dendrites of nucleus reticularis thalami (nRt), intracellular Ca2+ concentration increases were dominated by Ca2+ influx through T channels and shaped rhythmic bursting via competition between Ca2+-dependent small-conductance (SK)-type K+ channels and Ca2+ uptake pumps. Oscillatory bursting was initiated via selective activation of dendritically located SK2 channels, whereas Ca2+ sequestration by sarco/endoplasmic reticulum Ca2+-ATPases (SERCAs) and cumulative T channel inactivation dampened oscillations. Sk2-/- (also known as Kcnn2) mice lacked cellular oscillations, showed a greater than threefold reduction in low-frequency rhythms in the electroencephalogram of non-rapid-eye-movement sleep and had disrupted sleep. Thus, the interplay of T channels, SK2 channels and SERCAs in nRt dendrites comprises a specialized Ca2+ signaling triad to regulate oscillatory dynamics related to sleep.