The characteristic cohomology class of a triangulated category

This is the final version of a series of papers uploaded in May 25, 2005. We have splitted the long last paper of the previous version in two parts to make it easier to understand. The results are essentially the same, although the presentation has changed substantially. The first three papers have not changed. This is a collection of five papers on the foundation of triangulated categories in the context of groupoid-enriched categories, termed track categories, and characteristic cohomology classes. As a main result it is shown that given an additive category A with a translation functor t: A --> A and a class V in translation cohomology H^3(A,t) then two simple properties of V imply that (A,t) is a triangulated category. The cohomology class V yields an equivalence class (B,[s]) where B is a track category with homotopy category A and [s] is the homotopy class of a pseudofunctor s: B --> B inducing t. The two properties of V correspond to natural axioms on B and s which again imply that (A,t) is a triangulated category. The five papers of this volume depend on each other by cross references, but each paper can be read independently of the others so that the reader is free to choose one of the papers to start. Each paper has its own abstract, introduction and literature.Comment: 166 pages, some diagrams do not appear correctly in the DVI fil

The Drosophila DIAP1 protein is required to prevent accumulation of a continuously generated, processed form of the apical caspase DRONC

Although loss of the inhibitor of apoptosis (LAP) protein DIAP1 has been shown to result in caspase activation and spontaneous cell death in Drosophila cells and embryos, the point at which DIAP1 normally functions to inhibit caspase activation is unknown. Depletion of the DIAP1 protein in Drosophila S2 cells or the Sf-IAP protein in Spodoptera frugiperda Sf21 cells by RNA interference (RNAi) or cycloheximide treatment resulted in rapid and widespread caspase-dependent apoptosis. Co-silencing of dronc or dark largely suppressed this apoptosis, indicating that DIAP1 is normally required to inhibit an activity dependent on these proteins. Silencing of dronc also inhibited DRICE processing following stimulation of apoptosis, demonstrating that DRONC functions as an apical caspase in S2 cells. Silencing of diap1 or treatment with UV light induced DRONC processing, which occurred in two steps. The first step appeared to occur continuously even in the absence of an apoptotic signal and to be dependent on DARK because full-length DRONC accumulated when dark was silenced in non-apoptotic cells. In addition, treatment with the proteasome inhibitor MG132 resulted in accumulation of this initially processed form of DRONC, but not full-length DRONC, in non-apoptotic cells. The second step in DRONC processing was observed only in apoptotic cells. These results indicate that the initial step in DRONC processing occurs continuously via a DARK-dependent mechanism in Drosophila cells and that DIAP1 is required to prevent excess accumulation of this first form of processed DRONC, presumably through its ability to act as a ubiquitin-protein ligase

Cleavage of the apoptosis inhibitor DIAP1 by the apical caspase DRONC in both normal and apoptotic drosophila cells

In Drosophila S2 cells, the apical caspase DRONC undergoes a low level of spontaneous autoprocessing. Unintended apoptosis is prevented by the inhibitor of apoptosis DIAP1, which targets the processed form of DRONC for degradation through its E3 ubiquitin protein ligase activity. Recent reports have demonstrated that shortly after the initiation of apoptosis in S2 cells, DIAP1 is cleaved following aspartate residue Asp-20 by the effector caspase DrICE. Here we report a novel caspase-mediated cleavage of DIAP1 in S2 cells. In both living and dying S2 cells, DIAP1 is cleaved by DRONC after glutamate residue Glu-205, located between the first and second BIR domains. The mutation of Glu-205 prevented the interaction of DIAP1 and processed DRONC but had no effect on the interaction with full-length DRONC. The mutation of Glu-205 also had a negative effect on the ability of overexpressed DIAP1 to prevent apoptosis stimulated by the proapoptotic protein Reaper or by UV light. These results expand our knowledge of the events that occur in the Drosophila apoptosome prior to and after receiving an apoptotic signal

Utilización de una pasta oral en el tratamiento de la septicemiacutánea ulcerativa

Se presenta un caso de septicemia cutánea ulcerativa en una tortuga de caparazón blando (Apalone ferox)

Toda brackets and cup-one squares for ring spectra

In this paper we prove the laws of Toda brackets on the homotopy groups of a connective ring spectrum and the laws of the cup-one square in the homotopy groups of a commutative connective ring spectrum.Comment: 22 page

Energy Discovery-Innovation Institutes: A Step Toward America's Energy Sustainability

Newsletter format, part of the "Blueprint for American Prosperity"http://deepblue.lib.umich.edu/bitstream/2027.42/88631/1/2009_Brookings_Energy_Summary.pd

Hubs of Transformation: Leveraging the Great Lakes Research Complex for Energy Innovation

http://deepblue.lib.umich.edu/bitstream/2027.42/88817/1/2010_Brookings_Hubs_of_Innovation.pd

Efecto de la defoliación en el cultivo de puerro (Allium porrum L.)

The foliar area loss is a typical damage in crops caused by fungus, insects or hailstorm. A lot of studies have been carried out to describe the effect of defoliation in the main herbaceous and woody crops. The results of two trials carried out in Valle Medio of the Ebro (Spain) are described in this study to determine the effects of different levels of defoliation in several phenological stages in leek crop. Four levels of defoliation were applied: control, slight, moderate and heavy, in six different phenological stages. Defoliations were carried out by means of a jet of water under pressure. According to the results observed, a close relationship between the yield loss with the percentage of defoliation and the crop stage was found. The most critical stage was at the beginning of the stem thickening in which there are maximum losses of 41% with 100% of defoliation. These experimental results were used to obtain regression equations in which the percentage of yield reduction is calculated in relation with the phenological stage and the percentage of defoliation. These equations can be used to improve simulation patterns of the leek growth in case of foliar damages caused by fungus, insect attacks or hailstorm.La pérdida de área foliar es un daño típico en los cultivos causado por ataques de hongos e insectos o por granizo. Se han realizado numerosos estudios para describir los efectos de la defoliación en los principales cultivos herbáceos y leñosos. En este trabajo se describen los resultados obtenidos en dos ensayos, llevados a cabo en el Valle Medio del Ebro (España), para determinar el efecto en el cultivo de puerro de diferentes niveles de defoliación aplicados en varios estados fenológicos. Se aplicaron cuatro niveles de defoliación: control, leve, medio y alto en seis estados fenológicos diferentes. La defoliación se llevó a cabo con una maquina de agua a presión. Se observó una estrecha relación entre la pérdida de cosecha, el porcentaje de defoliación y el estado fenológico en que se aplicó. El estado más crítico fue al inicio del engrosamiento del tallo en el cual se alcanzaron las mayores pérdidas, de un 41% para un 100% de defoliación. Estos resultados experimentales se utilizaron para obtener ecuaciones de regresión en las que se calculó el porcentaje de pérdida de cosecha en relación con el estado fenológico y el porcentaje de defoliación aplicado. Estas ecuaciones pueden ser utilizadas para mejorar los patrones de simulación de crecimiento del puerro en caso de daños foliares provocados por ataques de hongos o insectos o por granizo

Structural Modification and Metamagnetic Anomaly in the Ordered State of CeOs2Al10

A caged compound CeOs2Al10, crystallizing in the orthorhombic YbFe2Al10-type structure, undergoes a mysterious phase transition at T_0=29 K. We report the results of electron diffraction, magnetization, and magnetoresistance for single crystals. Superlattice reflections characterized by a wave vector q = (0, -2/3, 2/3) observed at 15 K indicate a structural modification in the ordered state. Activation-type behavior of the electrical resistivity along the three principal axes below 50 K suggests gap opening in the conduction band. The magnetic susceptibility \chi = M/B is highly anisotropic, \chi_a>\chi_c>\chi_b, all of which sharply decrease on cooling below T_0. Furthermore, a metamagnetic anomaly in the magnetization and a step in the magnetoresistance occur at B=6-8 T only when the magnetic field is applied parallel to the orthorhombic c axis. However, T_0 hardly changes under magnetic fields up to 14 T, irrespective of the field direction. By using these data, we present a B-T phase diagram and discuss several scenarios for the mysterious transition.Comment: 6 pages, 7 figures, accepted for publication in Phys. Rev.

Secondary homotopy groups

Secondary homotopy groups supplement the structure of classical homotopy groups. They yield a track functor on the track category of pointed spaces compatible with fiber sequences, suspensions and loop spaces. They also yield algebraic models of homotopy types with homotopy groups concentrated in two consecutive dimensions.Comment: We added further commets and references to make the paper more easily readabl