64 research outputs found

    Quantisations of piecewise affine maps on the torus and their quantum limits

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    For general quantum systems the semiclassical behaviour of eigenfunctions in relation to the ergodic properties of the underlying classical system is quite difficult to understand. The Wignerfunctions of eigenstates converge weakly to invariant measures of the classical system, the so called quantum limits, and one would like to understand which invariant measures can occur that way, thereby classifying the semiclassical behaviour of eigenfunctions. We introduce a class of maps on the torus for whose quantisations we can understand the set of quantum limits in great detail. In particular we can construct examples of ergodic maps which have singular ergodic measures as quantum limits, and examples of non-ergodic maps where arbitrary convex combinations of absolutely continuous ergodic measures can occur as quantum limits. The maps we quantise are obtained by cutting and stacking

    Anatomy of quantum chaotic eigenstates

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    The eigenfunctions of quantized chaotic systems cannot be described by explicit formulas, even approximate ones. This survey summarizes (selected) analytical approaches used to describe these eigenstates, in the semiclassical limit. The levels of description are macroscopic (one wants to understand the quantum averages of smooth observables), and microscopic (one wants informations on maxima of eigenfunctions, "scars" of periodic orbits, structure of the nodal sets and domains, local correlations), and often focusses on statistical results. Various models of "random wavefunctions" have been introduced to understand these statistical properties, with usually good agreement with the numerical data. We also discuss some specific systems (like arithmetic ones) which depart from these random models.Comment: Corrected typos, added a few references and updated some result

    Efeito da concentração de hipoclorito de sódio na desisfestação de sementes de Brachiaria brizantha para cultivo in vitro.

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    A Brachiaria brizantha È uma das mais importantes forrageiras cultivadas no Brasil sendo respons·vel por grande parte da ·rea coberta por pastagens. A utilizaÁ„o da biotecnologia est· sendo cada vez mais demandada no melhoramento vegetal e neste contexto a cultura de tecidos tem importante papel. A contaminaÁ„o È um dos principais fatores que dificultam o cultivo in vitro, em especial quando se trata da introduÁ„o de sementes no meio de cultura, pois os agentes patogÍnicos dificultam a germinaÁ„o bem como o desenvolvimento das pl‚ntulas. O objetivo do trabalho foi determinar a melhor concentraÁ„o de hipoclorito de sÛdio para desinfestaÁ„o de sementes para cultivo in vitro de B.brizantha. Foram utilizadas sementes da cultivar Marandu, as quais foram tratadas com trÍs concentraÁıes do agente, 1%, 1,5% e 2%, durante 16 horas de submers„o. O delineamento utilizado foi inteiramente casualizado com 4 repetiÁıes. ApÛs tratadas, as sementes foram introduzidas em meio de cultivo sob condiÁıes assÈpticas e mantidas em c‚mara de crescimento. As observaÁıes foram realizadas aos sete dias e o tratamento que apresentou a melhor porcentagem de germinaÁ„o e menor contaminaÁ„o, foi com a concentraÁ„o de 2% de hipoclorito de sÛdi

    Efeito da concentração de hipoclorito de sódio na desinfestação de sementes de Brachiaria brizantha para cultivo in vitro.

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    A Brachiaria brizantha é uma das mais importantes forrageiras cultivadas no Brasil sendo responsável por grande parte da área coberta por pastagens. A utilização da biotecnologia está sendo cada vez mais demandada no melhoramento vegetal e neste contexto a cultura de tecidos tem importante papel. A contaminação é um dos principais fatores que dificultam o cultivo in vitro, em especial quando se trata da introdução de sementes no meio de cultura, pois os agentes patogênicos dificultam a germinação bem como o desenvolvimento das plântulas. O objetivo do trabalho foi determinar a melhor concentração de hipoclorito de sódio para desinfestação de sementes para cultivo in vitro de Brachiaria brizantha. Foram utilizadas sementes da cultivar Marandu, as quais foram tratadas com três concentrações do agente, 1%, 1,5% e 2%, durante 16 horas de submersão. O delineamento utilizado foi inteiramente casualizado com 4 repetições. Após tratadas, as sementes foram introduzidas em meio de cultivo sob condições assépticas e mantidas em câmara de crescimento. As observações foram realizadas aos sete dias e o tratamento que apresentou a melhor porcentagem de germinação e menor contaminação, foi com a concentração de 2% de hipoclorito de sódio

    Aluminum induces inflammatory and proteolytic alterations in human monocytic cell line

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    none4noThe increasing exposure to aluminum has been linked with the development of different human pathologies (e.g., breast cancer, myofasciitis, neurodegenerative diseases), probably due to the consistent presence of aluminum salts in widely diffused cosmetic products and vaccines. However, the mechanisms underlying immunologic and proliferative alterations still remain unknown. In the present study we investigated the ability of different aluminum compounds (i.e., aluminum chloride vs Imject® Alum, a mixture of aluminum and magnesium hydroxide) to trigger both inflammatory and proteolytic responses in U-937 human monocytic cell line. We demonstrated, by multiplex immunoassay analyses, that monocytic cells treated with both Imject Alum and aluminum chloride showed different and peculiar expression profiles of 27 inflammatory mediators and 5 matrix metalloproteinases, with respect to untreated control cells. In particular, we found dose-dependent significantly increased levels of pro-inflammatory cytokines, growth factors, and chemoattractant chemokines; whereas among metalloproteinases, only collagenolytic protease showed a significant dose-dependent increase in Imject-treated cells with respect to controls and Al-chloride treated cells. Noteworthy, we found only in Imject Alum-treated cells the significant positive correlations among collagenolytic metalloproteinase and increased expression of pro-inflammatory chemokines, suggesting a possible involvement of aluminum in regulating the acute inflammatory responses. In agreement to emerging evidences, for the first time we demonstrated that the treatment of monocyte cells with aluminum-based adjuvant is able to induce an inflammatory status and a proteolytic cascade activation. In fact, the cell treatment with Imject Alum induced increased levels of several cytokines and proteinases, suggesting these monocyte mediators as possible biomarkers for aluminum-linked diseases. The identification of the biochemical pathways involved in Al-induced cell injury pave the way for improving the knowledge on the potential impact of aluminum in human physio-pathology.openLigi, D; Santi, M; Croce, L; Mannello, FLigi, Daniela; Santi, Martina; Croce, L; Mannello, Ferdinand

    A review of hyperfibrinolysis in cats and dogs

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    The fibrinolytic system is activated concurrently with coagulation; it regulates haemostasis and prevents thrombosis by restricting clot formation to the area of vascular injury and dismantling the clot as healing occurs. Dysregulation of the fibrinolytic system, which results in hyperfibrinolysis, may manifest as clinically important haemorrhage. Hyperfibrinolysis occurs in cats and dogs secondary to a variety of congenital and acquired disorders. Acquired disorders associated with hyperfibrinolysis, such as trauma, cavitary effusions, liver disease and Angiostrongylus vasorum infection, are commonly encountered in primary care practice. In addition, delayed haemorrhage reported in greyhounds following trauma and routine surgical procedures has been attributed to a hyperfibrinolytic disorder, although this has yet to be characterised. The diagnosis of hyperfibrinolysis is challenging and, until recently, has relied on techniques that are not readily available outside referral hospitals. With the recent development of point‐of‐care viscoelastic techniques, assessment of fibrinolysis is now possible in referral practice. This will provide the opportunity to target haemorrhage due to hyperfibrinolysis with antifibrinolytic drugs and thereby reduce associated morbidity and mortality. The fibrinolytic system and the conditions associated with increased fibrinolytic activity in cats and dogs are the focus of this review article. In addition, laboratory and point‐of‐care techniques for assessing hyperfibrinolysis and antifibrinolytic treatment for patients with haemorrhage are reviewed

    Mis-spliced transcripts generate de novo proteins in TDP-43–related ALS/FTD

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    Functional loss of TDP-43, an RNA binding protein genetically and pathologically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), leads to the inclusion of cryptic exons in hundreds of transcripts during disease. Cryptic exons can promote the degradation of affected transcripts, deleteriously altering cellular function through loss-of-function mechanisms. Here, we show that mRNA transcripts harboring cryptic exons generated de novo proteins in TDP-43–depleted human iPSC–derived neurons in vitro, and de novo peptides were found in cerebrospinal fluid (CSF) samples from patients with ALS or FTD. Using coordinated transcriptomic and proteomic studies of TDP-43–depleted human iPSC–derived neurons, we identified 65 peptides that mapped to 12 cryptic exons. Cryptic exons identified in TDP-43–depleted human iPSC–derived neurons were predictive of cryptic exons expressed in postmortem brain tissue from patients with TDP-43 proteinopathy. These cryptic exons produced transcript variants that generated de novo proteins. We found that the inclusion of cryptic peptide sequences in proteins altered their interactions with other proteins, thereby likely altering their function. Last, we showed that 18 de novo peptides across 13 genes were present in CSF samples from patients with ALS/FTD spectrum disorders. The demonstration of cryptic exon translation suggests new mechanisms for ALS/FTD pathophysiology downstream of TDP-43 dysfunction and may provide a potential strategy to assay TDP-43 function in patient CSF

    A Uniform Strong Spectral Gap for Congruence Covers of a Compact Quotient of

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