225 research outputs found

    Spectra associated to symmetric monoidal bicategories

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    We show how to construct a Gamma-bicategory from a symmetric monoidal bicategory, and use that to show that the classifying space is an infinite loop space upon group completion. We also show a way to relate this construction to the classic Gamma-category construction for a bipermutative category. As an example, we use this machinery to construct a delooping of the K-theory of a bimonoidal category as defined by Baas-Dundas-Rognes.Comment: 27 pages; originally submitted as: "An Infinite Loop Space Structure for K-theory of Bimonoidal Categories", this version has essentially the same content, but the organization is differen

    Pseudomyxoma-type Invasion in Gastrointestinal Adenocarcinomas of Endometrium and Cervix: A Report of 2 Cases

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    Summary: This paper presents a clinicopathologic and immunohistochemical report of 2 gastrointestinal-type tumors, one in the endometrium and the other in the cervix. Both showed extensive invasion into the pelvic structures with acellular mucin, identical to pseudomyxoma but in the absence of appendiceal or ovarian tumors. Case 1 was an 81- yr-old female with a Stage III endometrial gastrointestinal-type adenocarcinoma who had had an endometrial polyp with intestinal metaplasia 4 yr previously. Case 2 was a 68-yr-old female with Stage IIIB endocervical gastrointestinal-type adenocarcinoma. Both were associated with a pseudomyxoma type of invasion, which in the endometrial case was transmural through the myometrium, and in the cervical case involved parametria, pelvic floor, and lymph nodes. Immunohistochemically, both tumors had a gastrointestinal phenotype coexpressing cytokeratins 7 and 20, CDX2, villin, MUC2, MUC5AC, and MUC6 and were negative for human papillomavirus, analyzed by realtime polymerase chain reaction. The first case exemplifies intestinal endometrial metaplasia as a precursor lesion of the rare gastrointestinal type of adenocarcinoma and also proves its progression into carcinoma. The second case exemplifies the highly aggressive nature of cervical invasion forming mucin lakes. Extensive pseudomyxoma in the uterus and cervix was associated with high clinical stages with marked lymphovascular invasion and lymph node metastase

    An Explicit Framework for Interaction Nets

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    Interaction nets are a graphical formalism inspired by Linear Logic proof-nets often used for studying higher order rewriting e.g. \Beta-reduction. Traditional presentations of interaction nets are based on graph theory and rely on elementary properties of graph theory. We give here a more explicit presentation based on notions borrowed from Girard's Geometry of Interaction: interaction nets are presented as partial permutations and a composition of nets, the gluing, is derived from the execution formula. We then define contexts and reduction as the context closure of rules. We prove strong confluence of the reduction within our framework and show how interaction nets can be viewed as the quotient of some generalized proof-nets

    W196 and the ß -Hairpin Motif Modulate the Redox Switch of Conformation and the Biomolecular Interaction Network of the Apoptosis-Inducing Factor

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    The human apoptosis-inducing factor (hAIF) is a moonlight flavoprotein involved in mitochondrial respiratory complex assembly and caspase-independent programmed cell death. These functions might be modulated by its redox-linked structural transition that enables hAIF to act as a NAD(H/+) redox sensor. Upon reduction with NADH, hAIF undergoes a conformational reorganization in two specific insertions - the flexible regulatory C-loop and the 190-202 ß-harpin - promoting protein dimerization and the stabilization of a long-life charge transfer complex (CTC) that modulates its monomer-dimer equilibrium and its protein interaction network in healthy mitochondria. In this regard, here, we investigated the precise function of the ß-hairpin in the AIF conformation landscape related to its redox mechanism, by analyzing the role played by W196, a key residue in the interaction of this motif with the regulatory C-loop. Mutations at W196 decrease the compactness and stability of the oxidized hAIF, indicating that the ß-hairpin and C-loop coupling contribute to protein stability. Kinetic studies complemented with computational simulations reveal that W196 and the ß-hairpin conformation modulate the low efficiency of hAIF as NADH oxidoreductase, contributing to configure its active site in a noncompetent geometry for hydride transfer and to stabilize the CTC state by enhancing the affinity for NAD+. Finally, the ß-hairpin motif contributes to define the conformation of AIF's interaction surfaces with its physiological partners. These findings improve our understanding on the molecular basis of hAIF''s cellular activities, a crucial aspect for clarifying its associated pathological mechanisms and developing new molecular therapies

    Evaluación de los riegos de la Comunidad de Regantes V del Canal de las Bardenas

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    14 Pag., 2 Tabl., 1 Fig.[ES] En este artículo se presentan los resultados de las evaluaciones de riego que se han llevado a cabo dentro de la segunda fase del trabajo denominado “Mejora de la Gestión Integral del Agua de Riego en la Comunidad de Regantes V del Canal de Bardenas”. El 80 % de la superficie de esta comunidad está ocupado por suelos de plataformas residuales, mientras que el resto son suelos de aluvial. Para caracterizar la capacidad de retención de agua de los suelos (CRA) se realizó un muestro en el que se describieron 50 perfiles. Para determinar la infiltración de los suelos y los índices de calidad del riego por superficie se realizaron 50 evaluaciones de riego. Un adecuado manejo del agua a nivel de parcela y unas texturas francas-franco arenosas permiten alcanzar niveles de eficiencia medios en las parcelas de las plataformas (53 % de media), cuyos suelos se caracterizan por una baja CRA (60 mm de media). En aluviales la eficiencia llega hasta un 80 % de media, gracias a las elevadas capacidades de retención de agua de estos suelos (182 mm de media). Actualmente se está realizado un reaprovechamiento de las aguas de desagüe que posiblemente provoque que la eficiencia a nivel de comunidad sea mayor que la obtenida a nivel de parcela. Estos resultados permiten pensar que la modernización de los regadíos, mediante el cambio a un sistema de riego presurizado, tendría un fuerte impacto sobre la eficiencia en parcela, aunque el impacto sobre la eficiencia en la comunidad sería menor. La modernización tendría resultados muy beneficiosos social y económicamente para los agricultores, además de mejorar la calidad de las aguas de los ríos que atraviesan la comunidad.[EN] Results of the irrigation evaluations performed in the second phase of the project “Improvement of the Water Irrigation Integral Management in the Comunidad de Regantes V del Canal de Bardenas” are presented in this paper. An 80 % of the area of the Irrigation District is occupied by soils of residual platforms, and the rest of the soils are alluvial. A soil survey was performed for characterising the water holding capacity (WHC) of the soils, using 50 soil profiles. A total of 50 irrigation evaluations was performed for determining soil infiltration and the performance indexes of surface irrigation in the study area. An adequate water management in border irrigation and loam-sandy loam textures permit to attain 53 % application efficiency in platforms, whose soils are characterized by a low WHC (with an average of 60 mm). In alluvial soils the application efficiency is higher, with an average of 80 %, due to the high water holding capacity of these soils (an average of 182 mm). Currently, The district is enforcing a program for irrigation return flows reuse. This program surely results in an irrigation district efficiency substantially higher that the average application efficiency. With these results is possible to think that an irrigation modernization, through a change to a pressurized irrigation system will severely improve the application efficiency, but the effect on the irrigation district efficiency will only be moderate. However, this modernisation would have great social and economical benefits for farmers, and also, the water quality of rivers crossing the irrigation district will be improved.Este proyecto de investigación ha sido cofinanciado por la CICYT, por Fondos FEDER, por el CONSI+D y por la Comunidad de Regantes V de Bardenas.Peer reviewe

    Identification of inhibitors targeting ferredoxin-NADP+ reductase from the xanthomonas citri subsp. Citri phytopathogenic bacteria

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    Ferredoxin-NADP(H) reductases (FNRs) deliver NADPH or low potential one-electron donors to redox-based metabolism in plastids and bacteria. Xanthomonas citri subsp. citri (Xcc) is a Gram-negative bacterium responsible for citrus canker disease that affects commercial citrus crops worldwide. The Xcc fpr gene encodes a bacterial type FNR (XccFPR) that contributes to the bacterial response to oxidative stress conditions, usually found during plant colonization. Therefore, XccFPR is relevant for the pathogen survival and its inhibition might represent a strategy to treat citrus canker. Because of mechanistic and structural differences from plastidic FNRs, XccFPR is also a potential antibacterial target. We have optimized an activity-based high-throughput screening (HTS) assay that identifies XccFPR inhibitors. We selected 43 hits from a chemical library and narrowed them down to the four most promising inhibitors. The antimicrobial effect of these compounds was evaluated on Xcc cultures, finding one with antimicrobial properties. Based on the functional groups of this compound and their geometric arrangement, we identified another three XccFPR inhibitors. Inhibition mechanisms and constants were determined for these four XccFPR inhibitors. Their specificity was also evaluated by studying their effect on the plastidic Anabaena PCC 7119 FNR, finding differences that can become interesting tools to discover Xcc antimicrobials

    On the braiding of an Ann-category

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    A braided Ann-category \A is an Ann-category \A together with the braiding cc such that (\A, \otimes, a, c, (I,l,r)) is a braided tensor category, and cc is compatible with the distributivity constraints. The paper shows the dependence of the left (or right) distributivity constraint on other axioms. Hence, the paper shows the relation to the concepts of {\it distributivity category} due to M. L. Laplaza and {\it ring-like category} due to A. Frohlich and C.T.C Wall. The center construction of an almost strict Ann-category is an example of an unsymmetric braided Ann-category.Comment: 20 page

    Simulación computacional para la predicción de acoplamiento enzima-sustrato: Identificación del sitio de unión del coenzima en la FNR del patógeno Leptospira interrogans

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    La actividad catalítica de la ferredoxina-NADP+ reductasa de la bacteria patógena Leptospira interrogans (LepFNR) comprende la transferencia de electrones entre el coenzima NADPH y aceptores de un solo electrón y bajo potencial. Para ello, en la primera etapa de reacción, debe tener lugar la transferencia de un hidruro desde el anillo de nicotinamida del NADPH y el anillo de isoaloxazina del cofactor FAD de la enzima. Esto requiere una aproximación del carbono 4N (C4N) de la nicotinamida al nitrógeno 5 (N5) de la isoaloxazina por la cara re de dicho anillo. Sin embargo, la cara re del anillo se encuentra protegida por el aminoácido C-terminal, Tyr314, que interacciona por apilamiento π con la flavina. Por el momento, no se dispone experimentalmente de una estructura cristalográfica del complejo LepFNR:NADPH en una disposición catalíticamente competente. Por similitud con los miembros de la familia tipo plastídico, se ha propuesto un mecanismo en tres etapas para el acoplamiento, en el que el extremo 2’P-AMP del ligando interaccionaría en primer lugar, induciendo cambios conformacionales en la enzima que permitirían el acceso del anillo de nicotinamida del coenzima al sitio activo. Con objeto de validar esta posibilidad para el acoplamiento, en este trabajo se han utilizado técnicas basadas en mecánica molecular, incluyendo acoplamiento molecular enzima-sustrato y dinámica molecular con campos de fuerzas CHARMm. A través de las diferentes simulaciones moleculares realizadas se han descrito las principales interacciones de reconocimiento entre NADPH y LepFNR, así como los cambios conformacionales producidos por la unión de la mitad 2’P-AMP del coenzima NADPH. Los resultados computacionales que aquí se aportan indican que la unión del coenzima a LepFNR ocurre de forma similar a la descrita en el caso de las FNRs fotosintéticas

    Quantum Speedup and Categorical Distributivity

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    This paper studies one of the best known quantum algorithms - Shor's factorisation algorithm - via categorical distributivity. A key aim of the paper is to provide a minimal set of categorical requirements for key parts of the algorithm, in order to establish the most general setting in which the required operations may be performed efficiently. We demonstrate that Laplaza's theory of coherence for distributivity provides a purely categorical proof of the operational equivalence of two quantum circuits, with the notable property that one is exponentially more efficient than the other. This equivalence also exists in a wide range of categories. When applied to the category of finite dimensional Hilbert spaces, we recover the usual efficient implementation of the quantum oracles at the heart of both Shor's algorithm and quantum period-finding generally; however, it is also applicable in a much wider range of settings.Comment: 17 pages, 11 Figure

    Balancing the dilution and oddity effects: Decisions depend on body size

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    Background Grouping behaviour, common across the animal kingdom, is known to reduce an individual's risk of predation; particularly through dilution of individual risk and predator confusion (predator inability to single out an individual for attack). Theory predicts greater risk of predation to individuals more conspicuous to predators by difference in appearance from the group (the ‘oddity’ effect). Thus, animals should choose group mates close in appearance to themselves (eg. similar size), whilst also choosing a large group. Methodology and Principal Findings We used the Trinidadian guppy (Poecilia reticulata), a well known model species of group-living freshwater fish, in a series of binary choice trials investigating the outcome of conflict between preferences for large and phenotypically matched groups along a predation risk gradient. We found body-size dependent differences in the resultant social decisions. Large fish preferred shoaling with size-matched individuals, while small fish demonstrated no preference. There was a trend towards reduced preferences for the matched shoal under increased predation risk. Small fish were more active than large fish, moving between shoals more frequently. Activity levels increased as predation risk decreased. We found no effect of unmatched shoal size on preferences or activity. Conclusions and Significance Our results suggest that predation risk and individual body size act together to influence shoaling decisions. Oddity was more important for large than small fish, reducing in importance at higher predation risks. Dilution was potentially of limited importance at these shoal sizes. Activity levels may relate to how much sampling of each shoal was needed by the test fish during decision making. Predation pressure may select for better decision makers to survive to larger size, or that older, larger fish have learned to make shoaling decisions more efficiently, and this, combined with their size relative to shoal-mates, and attractiveness as prey items influences shoaling decisions
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