Higher-dimensional study of extensions via torsors

Let S be a site. First we define the 3-category of torsors under a Picard S-2-stack and we compute its homotopy groups. Using calculus of fractions we define also a pure algebraic analogue of the 3-category of torsors under a Picard S-2-stack. Then we describe extensions of Picard S-2-stacks as torsors endowed with a group law on the fibers. As a consequence of such a description, we show that any Picard S-2-stack admits a canonical free partial left resolution that we compute explicitly. Moreover we get an explicit right resolution of the 3-category of extensions of Picard S-2-stacks in terms of 3-categories of torsors. Using the homological interpretation of Picard S-2-stacks, we rewrite this three categorical dimensions higher right resolution in the derived category of abelian sheaves on S.Comment: We change the title and we add new result

Feeding habits of three seal species at the Danco Coast, Antarctica: A re-assessment

The analysis of prey overlap among Weddell, Antarctic fur and leopard seals was conducted using fecal samples collected at the Danco Coast, Antarctic Peninsula, in 1998 and 2000. The re-occurrence of prey species was moderate in samples collected in 1998, and low in 2000, and reflects resource partitioning among seal species. Prey species that mostly co-occurred in seals' diet were the Antarctic krill Euphausia superba, bivalves, and the myctophids Gymnoscopelus nicholsi and Electrona antarctica. A dietary similarity index of prey overlap has been calculated and demonstrates evident fluctuations in pairwise comparisons between the seal species. The highest and lowest values of prey overlap were observed between Antarctic fur seals and leopard seals, and between Weddell seals and leopard seals, respectively. Prey overlap between Antarctic fur seals and Weddell seals was moderate in both seasons.Fil: Casaux, Ricardo Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Bertolin, María Lila. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Carlini, A.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentin

Uniqueness properties for discrete equations and Carleman estimates

Using Carleman estimates, we give a lower bound for solutions to the discrete Schrödinger equation in both dynamic and stationary settings that allows us to prove uniqueness results, under some assumptions on the decay of the solutions

A higher Angiogenin expression is associated with a non-nuclear Maspin location in laryngeal carcinoma

Objectives. In numerous malignancies, angiogenin (ANG) and Maspin are important proangiogenic and antiangiogenic regulators, respectively. The aim of this study was to identify potential relationships between the biological roles of these two proteins in laryngeal squamous cell carcinoma (LSCC). Methods. Immunohistochemical staining for ANG and Maspin was performed on specimens from 76 consecutive LSCC patients treated with surgery alone, considering the subcellular pattern of Maspin expression. Univariate and multivariate statistical models were used for prognostic purposes. Results. On univariate analysis, a different level of ANG expression was seen for patients stratified by subcellular Maspin expression pattern: the mean ANG expression was higher in cases with a nonnuclear MASPIN expression than in those with a nuclear pattern (P=0.002). Disease-free survival (DFS; in months) differed significantly when patients were stratified by N stage (P=0.01). Patients whose Maspin expression was nonnuclear (i.e., it was cytoplasmic or there was none) had a significantly higher recurrence rate (P<0.001), and shorter DFS (P=0.01) than those with a nuclear Maspin pattern. The mean ANG expression was significantly higher in cases with loco-regional recurrent disease (P=0.007); and patients with an ANG expression 655.0% had a significantly shorter DFS than those with an ANG expression <5.0% (P=0.007). On multivariate analysis, ANG expression 655.0% was a significant, independent, negative prognostic factor in terms of DFS (P=0.041). Conclusion. Our results support the hypothesis that a higher ANG expression is associated with a nonnuclear Maspin expression pattern in patients with LSCC. Further studies are needed to clarify the relationship between the ANG and Maspin pathways, and their potential diagnostic and therapeutic role in LSCC

Plants from the Brazilian Cerrado with antimycobacterial effect

Tuberculosis constitutes a serious public health problem because it has multi-resistant forms that require treatment that is both difficult and extensive. There is a need to develop new antimycobacterial compounds, and plants represent a source of therapeutic resources. This study analyzed antimycobacterial action in eight extracts from plants found in the Brazilian Cerrado. The results showed significant inhibitory concentrations in relation to Mycobacterium tuberculosis, especially from the extracts of Apuleia molaris and Ouratea spectabilis, both of which presented reduced cytotoxic effects. Fractionation revealed a hexane fraction of A. molaris with significant and promising activity regarding future in vivo assays