8,617 research outputs found

    Searches for Heavy Neutrinos at the CERN SPS

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    Searches for heavy neutrinos can be successfully performed by fixed target experiments at the CERN SPS. New results obtained by the NA62 and NA48/2 kaon experiments are summarized in this paper. The physics potential of future projects exploiting SPS protons with beam dump facilities to enlarge the sensitivity to heavy neutrinos above the kaon mass limit are also outlined.Comment: 10 pages, 6 figures, NuPhys2017 conference proceedings, reference added to section

    The Drosophila histone variant H2A.V works in concert with HP1 to promote kinetochore-driven microtubule formation

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    Unlike other organisms that have evolved distinct H2A variants for different functions, Drosophila melanogaster has just one variant which is capable of filling many roles. This protein, H2A.V, combines the features of the conserved variants H2A.Z and H2A.X in transcriptional control/heterochromatin assembly and DNA damage response, respectively. Here we show that mutations in the gene encoding H2A.V affect chromatin compaction and perturb chromosome segregation in Drosophila mitotic cells. A microtubule (MT) regrowth assay after cold exposure revealed that loss of H2A.V impairs the formation of kinetochore-driven (k) fibers, which can account for defects in chromosome segregation. All defects are rescued by a transgene encoding H2A.V that lacks the H2A.X function in the DNA damage response, suggesting that the H2A.Z (but not H2A.X) functionality of H2A.V is required for chromosome segregation. We also found that loss of H2A.V weakens HP1 localization, specifically at the pericentric heterochromatin of metaphase chromosomes. Interestingly, loss of HP1 yielded not only telomeric fusions but also mitotic defects similar to those seen in H2A.V null mutants, suggesting a role for HP1 in chromosome segregation. We also show that H2A.V precipitates HP1 from larval brain extracts indicating that both proteins are part of the same complex. Moreover, we found that the overexpression of HP1 rescues chromosome missegregation and defects in the kinetochore-driven k-fiber regrowth of H2A.V mutants indicating that both phenotypes are influenced by unbalanced levels of HP1. Collectively, our results suggest that H2A.V and HP1 work in concert to ensure kinetochore-driven MT growth

    Portfolio Selection with minimum transaction lots: an approach with dual expected utility

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    In this paper we analyse the portfolio selectionproblem with minimum transactionlots in the context of non-expected utility theory. We assume that the decisionmaker ranks the alternatives by using a specific DualExpectedUtility. This functionallows portfolio values less or equal a fixed benchmark tobe weighted inadifferent way from values greater than the fixedbenchmark. Under normallydistributedreturns and opportunechoice ofthe benchmark, the suggested approach leads to an NP-complete problemandhas the advantage ofusing mixed linear programming to obtainthe optimal portfolio. We also show resultsobtained by implementing the model on the Italian stock market. (keywords: dual expectedutility, portfolio selection, NP-completeness, linear programming with mixed variables)dual expected utility, portfolio selection, NP-completeness, linear programming with

    Exchange your knowledge on plant gene families

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    Genomic analysis of NAC transcription factors in banana (Musa acuminata) and definition of NAC orthologous groups for monocots and dicots

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    Identifying the molecular mechanisms underlying tolerance to abiotic stresses is important in crop breeding. A comprehensive understanding of the gene families associated with drought tolerance is therefore highly relevant. NAC transcription factors form a large plant-specific gene family involved in the regulation of tissue development and responses to biotic and abiotic stresses. The main goal of this study was to set up a framework of orthologous groups determined by an expert sequence comparison of NAC genes from both monocots and dicots. In order to clarify the orthologous relationships among NAC genes of different species, we performed an in-depth comparative study of four divergent taxa, in dicots and monocots, whose genomes have already been completely sequenced: Arabidopsis thaliana, Vitis vinifera, Musa acuminata and Oryza sativa. Due to independent evolution, NAC copy number is highly variable in these plant genomes. Based on an expert NAC sequence comparison, we propose forty orthologous groups of NAC sequences that were probably derived from an ancestor gene present in the most recent common ancestor of dicots and monocots. These orthologous groups provide a curated resource for large-scale protein sequence annotation of NAC transcription factors. The established orthology relationships also provide a useful reference for NAC function studies in newly sequenced genomes such as M. acuminata and other plant species

    Ultrasound-induced emulsification of subcritical carbon dioxide/water with and without surfactant as a strategy for enhanced mass transport

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    Pulsed ultrasound was used to disperse a biphasic mixture of CO2/H2O in a 1 dm3 high-pressure reactor at 30 °C/80 bar. A view cell positioned in-line with the sonic vessel allowed observation of a turbid emulsion which lasted approximately 30 min after ceasing sonication. Within the ultrasound reactor, simultaneous CO2-continuous and H2O-continuous environments were identified. The hydrolysis of benzoyl chloride was employed to show that at similar power intensities, comparable initial rates (1.6 ± 0.3 × 10–3 s–1 at 95 W cm–2) were obtained with those reported for a 87 cm3 reactor (1.8 ± 0.2 × 10–3 s–1 at 105 W cm–2), demonstrating the conservation of the physical effects of ultrasound in high-pressure systems (emulsification induced by the action of acoustic forces near an interface). A comparison of benzoyl chloride hydrolysis rates and benzaldehyde mass transport relative to the non-sonicated, ‘silent’ cases confirmed that the application of ultrasound achieved reaction rates which were over 200 times faster, by reducing the mass transport resistance between CO2 and H2O. The versatility of the system was further demonstrated by ultrasound-induced hydrolysis in the presence of the polysorbate surfactant, Tween, which formed a more uniform CO2/H2O emulsion that significantly increased benzoyl chloride hydrolysis rates. Finally, pulse rate was employed as a means of slowing down the rate of hydrolysis, further illustrating how ultrasound can be used as a valuable tool for controlling reactions in CO2/H2O solvent mixtures

    Guidelines for the Use of Native Mosses, Transplanted Mosses and Soils in Assessing Organic and Inorganic Contaminant Fallout

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    These guidelines on the use of mosses are of strategic importance in that they make it possible to harmonise the indications obtained from differing environments in terms of extent and, thereby, to compare them with results obtained using other methods. Thanks to their morphological features, mosses can be used as bioindicators to obtain fallout information for a significant number of organic and inorganic contaminants of human origin and determine the quantity of such contaminants deposited in soil. Analysis of both moss and soil is essential in identifying, and discriminating between, anthropic and natural sources of contaminant fallout.JRC.H.7-Land management and natural hazard

    Linee Guida per l'Utilizzo di Muschi Indigeni, Muschi Trapiantati e Suoli per Valutare le Ricadute di Contaminanti Organici e Inorganici

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    Le linee guida per i muschi rivestono una importanza strategica in quanto il loro utilizzo consente di uniformare le indicazioni che si ottengono in ambienti a differente estensione e pressione antropica, permettendo di raffrontare i risultati così ottenuti con altri metodi. Le caratteristiche morfologiche garantiscono il buon utilizzo dei muschi come bioaccumulatori per l¿ottenimento delle informazioni relative alle ricadute di un numero significativo di contaminanti organici e inorganici di origine antropica e di valutarne la quantità che si deposita al suolo. L¿abbinamento muschio-suolo è da ritenersi indispensabile per identificare e discriminare l¿origine delle ricadute dei contaminanti dovuta alle attività dell¿uomo da quella naturale. The guide lines for mosses present a strategic importance because their utilization permits to even the indications that obtain in different extension environments and human pressure, allowing to compare the results obtained with other methods. The morphological features guarantee the good utilization of mosses like bioindicators to obtain relevant information of fall out for a significant number of organic and inorganic contaminants of human origin and to appraise the quantity that is deposited to soil. Linking moss-soil is to retain indispensable to identify and discriminate the origin of contaminant fall out concerning man activities from soil origins.JRC.DDG.H.7-Land management and natural hazard
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