158 research outputs found

    Testing the b-value variability in Italy and its influence on Italian PSHA

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    The supposed b-value spatial variability is the central topic of many scientific works dealing with forecasting modeling applications or geological correlations. If used for seismicity rates determination, the b-value plays an important role in probabilistic seismic hazard assessment, but how much does it influence PSHA? In the logic tree approach used for the new probabilistic seismic hazard map of Italy, named MPS04 (MPS Working Group, 2004), one of the sources of epistemic uncertainty considered was the procedure for computing seismicity rates. Two alternatives were adopted: 1) compute the activity rates for each binned magnitude class and 2) compute a Gutenberg-Richter (1944) distribution. In the logic tree branches where Gutenberg-Richter distribution was adopted, the corresponding bvalue was evaluated for each seismogenic zone: it spans between 0.63 and 2.01. After analysing the b-value variability in the Italian region, this work evaluates the impact of setting the b-value equal to 1 on the results of seismic hazard assessment in terms of PGA and energy release compared to the choices adopted for MPS04 (MPS Working Group, 2004)

    Non-coding RNAs as prognostic markers for endometrial cancer

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    Endometrial cancer (EC) has been classified over the years, for prognostic and therapeutic purposes. In recent years, classification systems have been emerging not only based on EC clinical and pathological characteristics but also on its genetic and epigenetic features. Noncoding RNAs (ncRNAs) are emerging as promising markers in several cancer types, including EC, for which their prognostic value is currently under investigation and will likely integrate the present prognostic tools based on protein coding genes. This review aims to underline the importance of the genetic and epigenetic events in the EC tumorigenesis, by expounding upon the prognostic role of ncRNAs

    Y RNA: an overview of their role as potential biomarkers and molecular targets in human cancers

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    Y RNA are a class of small non-coding RNA that are largely conserved. Although their discovery was almost 40 years ago, their function is still under investigation. This is evident in cancer biology, where their role was first studied just a dozen years ago. Since then, only a few contributions were published, mostly scattered across different tumor types and, in some cases, also suffering from methodological limitations. Nonetheless, these sparse data may be used to make some estimations and suggest routes to better understand the role of Y RNA in cancer formation and characterization. Here we summarize the current knowledge about Y RNA in multiple types of cancer, also including a paragraph about tumors that might be included in this list in the future, if more evidence becomes available. The picture arising indicates that Y RNA might be useful in tumor characterization, also relying on non-invasive methods, such as the analysis of the content of extracellular vesicles (EV) that are retrieved from blood plasma and other bodily fluids. Due to the established role of Y RNA in DNA replication, it is possible to hypothesize their therapeutic targeting to inhibit cell proliferation in oncological patients

    Non-coding RNAs and endometrial cancer

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    Non-coding RNAs (ncRNAs) are involved in the regulation of cell metabolism and neoplastic transformation. Recent studies have tried to clarify the significance of these information carriers in the genesis and progression of various cancers and their use as biomarkers for the disease; possible targets for the inhibition of growth and invasion by the neoplastic cells have been suggested. The significance of ncRNAs in lung cancer, bladder cancer, kidney cancer, and melanoma has been amply investigated with important results. Recently, the role of long non-coding RNAs (lncRNAs) has also been included in cancer studies. Studies on the relation between endometrial cancer (EC) and ncRNAs, such as small ncRNAs or micro RNAs (miRNAs), transfer RNAs (tRNAs), ribosomal RNAs (rRNAs), antisense RNAs (asRNAs), small nuclear RNAs (snRNAs), Piwi-interacting RNAs (piRNAs), small nucleolar RNAs (snoRNAs), competing endogenous RNAs (ceRNAs), lncRNAs, and long intergenic ncRNAs (lincRNAs) have been published. The recent literature produced in the last three years was extracted from PubMed by two independent readers, which was then selected for the possible relation between ncRNAs, oncogenesis in general, and EC in particular

    Influence of Coulomb and Phonon Interaction on the Exciton Formation Dynamics in Semiconductor Heterostructures

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    A microscopic theory is developed to analyze the dynamics of exciton formation out of incoherent carriers in semiconductor heterostructures. The carrier Coulomb and phonon interaction is included consistently. A cluster expansion method is used to systematically truncate the hierarchy problem. By including all correlations up to the four-point (i.e. two-particle) level, the fundamental fermionic substructure of excitons is fully included. The analysis shows that the exciton formation is an intricate process where Coulomb correlations rapidly build up on a picosecond time scale while phonon dynamics leads to true exciton formation on a slow nanosecond time scale.Comment: 18 pages, 7 figure

    Bose-Einstein statistics in thermalization and photoluminescence of quantum well excitons

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    Quasi-equilibrium relaxational thermodynamics is developed to understand LA-phonon-assisted thermalization of Bose-Einstein distributed excitons in quantum wells. We study the quantum-statistical effects in the relaxational dynamics of the effective temperature of excitons T=T(t)T = T(t). When TT is less than the degeneracy temperature T0T_0, well-developed Bose-Einstein statistics of quantum well excitons leads to nonexponential and density-dependent thermalization. At low bath temperatures Tb0T_b \to 0 the thermalization of quantum-statistically degenerate excitons effectively slows down and T(t)1/lntT(t) \propto 1 / \ln t. We also analyze the optical decay of Bose-Einstein distributed excitons in perfect quantum wells and show how nonclassical statistics influences the effective lifetime τopt\tau_{opt}. In particular, τopt\tau_{opt} of a strongly degenerate gas of excitons is given by 2τR2 \tau_R, where τR\tau_R is the intrinsic radiative lifetime of quasi-two-dimensional excitons. Kinetics of resonant photoluminescence of quantum well excitons during their thermalization is studied within the thermodynamic approach and taking into account Bose-Einstein statistics. We find density-dependent photoluminescence dynamics of statistically degenerate excitons. Numerical modeling of the thermalization and photoluminescence kinetics of quasi-two-dimensional excitons are given for GaAs/AlGaAs quantum wells.Comment: 19 pages, 9 figures. Phys. Rev. B (accepted for publication

    Spazju

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    Ġabra ta’ poeżiji u proża li tinkludi: Meditation ta’ Wallace Ph. Gulia – Iċ-ċimiteru ta’ Lazzarett ta’ Patri Mattew – Niftakar ta’ C. Cassar – Ilsna ta’ C. Cassar – Ħsieb fix-xtajta ta’ Manwel u Josephine Cassar – Imħabba dejjiema ta’ Vincent Caruana – Ir-radda taż-żmien ta’ Vincent Ungaro – “Buona Pasqua!” ta’ Ġużè Borg Pantalleresco – Spazju ta’ Vincent Caruana.peer-reviewe

    Disa’ sinfonija ta’ Beethoven

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    Ġabra ta’ poeżiji u proża li tinkludi: It-trabokk ta’ W. Borg – Il-merħla tal-bnedmin ta’ Pawlu Aquilina – Versi ta’ Marċell Mizzi – Fuq ix-xmara Mersey, Manchester ta’ Wallace Ph. Gulia – Ħolma ta’ Peter A. Caruana – “Ma jiġix iżjed” ta’ A. Tabone – Id-dinja u l-bniedem ta’ Ġużè Chetcuti – Il-ġlied tal-ħbieb ta’ Marċell Mizzi – Lil ibni Danjel ta’ Manwel Cassar – Li kieku!!! ta’ C. Cassar – Id-disa’ sinfonija ta’ Beethoven ta’ Karmenu Mallia.peer-reviewe

    The Neuropeptide Allatostatin A Regulates Metabolism and Feeding Decisions in Drosophila

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    Coordinating metabolism and feeding is important to avoid obesity and metabolic diseases, yet the underlying mechanisms, balancing nutrient intake and metabolic expenditure, are poorly understood. Several mechanisms controlling these processes are conserved in Drosophila, where homeostasis and energy mobilization are regulated by the glucagon-related adipokinetic hormone (AKH) and the Drosophila insulin-like peptides (DILPs). Here, we provide evidence that the Drosophila neuropeptide Allatostatin A (AstA) regulates AKH and DILP signaling. The AstA receptor gene, Dar-2, is expressed in both the insulin and AKH producing cells. Silencing of Dar-2 in these cells results in changes in gene expression and physiology associated with reduced DILP and AKH signaling and animals lacking AstA accumulate high lipid levels. This suggests that AstA is regulating the balance between DILP and AKH, believed to be important for the maintenance of nutrient homeostasis in response to changing ratios of dietary sugar and protein. Furthermore, AstA and Dar-2 are regulated differentially by dietary carbohydrates and protein and AstA-neuronal activity modulates feeding choices between these types of nutrients. Our results suggest that AstA is involved in assigning value to these nutrients to coordinate metabolic and feeding decisions, responses that are important to balance food intake according to metabolic needs
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