183 research outputs found

    Continental degassing of helium in an active tectonic setting (northern Italy): the role of seismicity

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    In order to investigate the variability of helium degassing in continental regions, its release from rocks and emission into the atmosphere, here we studied the degassing of volatiles in a seismically active region of northern Italy (MwMAX = 6) at the Nirano-Regnano mud volcanic system. The emitted gases in the study area are CH4–dominated and it is the carrier for helium (He) transfer through the crust. Carbon and He isotopes unequivocally indicate that crustal-derived fluids dominate these systems. An high-resolution 3-dimensional reconstruction of the gas reservoirs feeding the observed gas emissions at the surface permits to estimate the amount of He stored in the natural reservoirs. Our study demonstrated that the in-situ production of 4He in the crust and a long-lasting diffusion through the crust are not the main processes that rule the He degassing in the region. Furthermore, we demonstrated that micro-fracturation due to the field of stress that generates the local seismicity increases the release of He from the rocks and can sustain the excess of He in the natural reservoirs respect to the steady-state diffusive degassing. These results prove that (1) the transport of volatiles through the crust can be episodic as function of rock deformation and seismicity and (2) He can be used to highlight changes in the stress field and related earthquakes

    Narrazioni e rappresentazioni del sacro femminile. Atti del convegno internazionale di studi in memoria di Giuseppe Martorana

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    Con Il riso di Demetra (1985), Giuseppe Martorana, professore ordinario di Storia delle Religioni presso l’Università degli studi di Palermo, esplorava le forme di religiosità al femminile in Sicilia, individuando tracce di continuità e persistenza che dai culti locali anellenici conducevano fino a forme di devozione cristiana. I contributi raccolti in questo volume intendono rendere omaggio alla sua memoria e riprendere criticamente i temi delle sue ricerche, indagando le narrazioni e le modalità di rappresentazione del sacro e del divino che coinvolgono l’elemento femminile, lungo un arco cronologico che dall’età del bronzo giunge all’età contemporanea e attraversa uno spazio geografico che dal Vicino Oriente conduce fino alla Grecia peninsulare e alla Sicilia. Tra le questioni sollevate, vi sono le minacce legate al mondo femminile; la consapevolezza del potenziale di rischio che alle donne è attribuito; l’agentività ad esse riconosciuta nello svolgimento dei rituali e nella partecipazione agli stessi; il ruolo del femminile nella tradizione narrativa. Ricorrenti sono inoltre i tentativi di ricostruzione degli spazi riservati al femminile, all’interno di culti specifici. Insieme a questi temi si avanzano riflessioni sulle continuità e sulle risemantizzazioni di elementi pertinenti a una religiosità antica al femminile osservabili in pratiche rituali tutt’ora vigenti. Un filo rosso attraversa questi i saggi: il necessario inquadramento storiografico di categorie e nozioni abusate come quella di “Grande madre”, di “religione mediterranea”, di “sostrato”, insieme a un ripensamento della categoria, fluida e sfuggente, di “sacro”.With Il Riso di Demetra (1985), Giuseppe Martorana, full professor of the History of Religions at the University of Palermo, explored the forms of feminine religiosity in Sicily, identifying traces of continuity and persistence that led from local annellenic cults to to forms of Christian devotion. The contributions collected in this volume intend to pay homage to her memory and critically resume the themes of her research, investigating the narratives and ways of representing the sacred and the divine that involve the female element, along a chronological span that from the age of bronze reaches the contemporary age and crosses a geographical space that from the Near East leads to peninsular Greece and Sicily. Among the issues raised, there are threats linked to the world of women; awareness of the risk potential that is attributed to women; the agency recognized to them in carrying out the rituals and participating in them; the role of the feminine in the narrative tradition. There are also recurrent attempts to reconstruct the spaces reserved for women, within specific cults. Along with these themes, reflections are advanced on the continuity and re-semantization of elements pertinent to an ancient feminine religiosity that can be observed in ritual practices that are still in force today. A common thread runs through these essays: the necessary classification historiographical of abused categories and notions such as that of "Great mother", of "Mediterranean religion", of "substratum", together with a rethinking of the fluid and elusive category of "sacred"

    Combinatorial control of temporal gene expression in the Drosophila wing by enhancers and core promoters

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    Abstract Background The transformation of a developing epithelium into an adult structure is a complex process, which often involves coordinated changes in cell proliferation, metabolism, adhesion, and shape. To identify genetic mechanisms that control epithelial differentiation, we analyzed the temporal patterns of gene expression during metamorphosis of the Drosophila wing. Results We found that a striking number of genes, approximately 50% of the Drosophila transcriptome, exhibited changes in expression during a time course of wing development. While cis-acting enhancer sequences clearly correlated with these changes, a stronger correlation was discovered between core-promoter types and the dynamic patterns of gene expression within this differentiating tissue. In support of the hypothesis that core-promoter type influences the dynamics of expression, expression levels of several TATA-box binding protein associated factors (TAFs) and other core promoter-associated components changed during this developmental time course, and a testes-specific TAF (tTAF) played a critical role in timing cellular differentiation within the wing. Conclusions Our results suggest that the combinatorial control of gene expression via cis-acting enhancer sequences and core-promoter types, determine the complex changes in gene expression that drive morphogenesis and terminal differentiation of the Drosophila wing epithelium.http://deepblue.lib.umich.edu/bitstream/2027.42/112935/1/12864_2012_Article_4965.pd

    A slow lopsided bar in the interacting dwarf galaxy IC 3167

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    We present surface photometry and stellar kinematics of IC 3167, a dwarf galaxy hosting a lopsided weak bar and infalling into the Virgo cluster. We measured the bar radius and strength from broad-band imaging and bar pattern speed by applying the Tremaine-Weinberg method to stellar-absorption integral-field spectroscopy. We derived the ratio of the corotation radius to bar radius (R = 1.7 + 0.5 - 0.3) from stellar kinematics and bar pattern speed. The probability that the bar is rotating slowly is more than twice as likely as that the bar is fast. This allows us to infer that the formation of this bar was triggered by the ongoing interaction rather than to internal processes.Comment: Accepted for pubblication in MNRAS Letter

    Hydrogeochemistry and Groundwater Quality Assessment in the High Agri Valley (Southern Italy)

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    The High Agri Valley (southern Italy) is one of the largest intermontane basin of the southern Apennines affected by intensive agricultural and industrial activities. The study of groundwater chemical features provides much important information useful in water resource management. In this study, hydrogeochemical investigations coupled with multivariate statistics, saturation indices, and stable isotope composition (δD and δ18O) were conducted in the High Agri Valley to determine the chemical composition of groundwater and to define the geogenic and anthropogenic influences on groundwater quality. Twenty-four sampling point ( including well and spring waters) have been examined. The isotopic data revealed that groundwater has a meteoric origin. Well waters, located on recent alluvial-lacustrine deposits in shallow porous aquifers at the valley floor, are influenced by seasonal rainfall events and show shallow circuits; conversely, spring waters from fissured and/or karstified aquifers are probably associated to deeper and longer hydrogeological circuits. The R -mode factor analysis shows that three factors explain 94% of the total variance, and F1 represents the combined effect of dolomite and silicate dissolution to explain most water chemistry. In addition, very low contents of trace elements were detected, and their distribution was principally related to natural input. Only two well waters, used for irrigation use, show critical issue for NO3- concentrations, whose values are linked to agricultural activities. Groundwater quality strongly affects the management of water resources, as well as their suitability for domestic, agricultural, and industrial uses. Overall, our results were considered fulfilling the requirements for the inorganic component of the Water Framework Directive and Italian legislation for drinking purposes. The water quality for irrigation is from "good to permissible" to "excellent to good" although salinity and relatively high content of Mg2+ can occasionally be critical

    Caenorhabditis elegans Cyclin D/CDK4 and Cyclin E/CDK2 Induce Distinct Cell Cycle Re-Entry Programs in Differentiated Muscle Cells

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    Cell proliferation and differentiation are regulated in a highly coordinated and inverse manner during development and tissue homeostasis. Terminal differentiation usually coincides with cell cycle exit and is thought to engage stable transcriptional repression of cell cycle genes. Here, we examine the robustness of the post-mitotic state, using Caenorhabditis elegans muscle cells as a model. We found that expression of a G1 Cyclin and CDK initiates cell cycle re-entry in muscle cells without interfering with the differentiated state. Cyclin D/CDK4 (CYD-1/CDK-4) expression was sufficient to induce DNA synthesis in muscle cells, in contrast to Cyclin E/CDK2 (CYE-1/CDK-2), which triggered mitotic events. Tissue-specific gene-expression profiling and single molecule FISH experiments revealed that Cyclin D and E kinases activate an extensive and overlapping set of cell cycle genes in muscle, yet failed to induce some key activators of G1/S progression. Surprisingly, CYD-1/CDK-4 also induced an additional set of genes primarily associated with growth and metabolism, which were not activated by CYE-1/CDK-2. Moreover, CYD-1/CDK-4 expression also down-regulated a large number of genes enriched for catabolic functions. These results highlight distinct functions for the two G1 Cyclin/CDK complexes and reveal a previously unknown activity of Cyclin D/CDK-4 in regulating metabolic gene expression. Furthermore, our data demonstrate that many cell cycle genes can still be transcriptionally induced in post-mitotic muscle cells, while maintenance of the post-mitotic state might depend on stable repression of a limited number of critical cell cycle regulators

    Context-Dependent Requirement for dE2F during Oncogenic Proliferation

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    The Hippo pathway negatively regulates the cell number in epithelial tissue. Upon its inactivation, an excess of cells is produced. These additional cells are generated from an increased rate of cell division, followed by inappropriate proliferation of cells that have failed to exit the cell cycle. We analyzed the consequence of inactivation of the entire E2F family of transcription factors in these two settings. In Drosophila, there is a single activator, dE2F1, and a single repressor, dE2F2, which act antagonistically to each other during development. While the loss of the activator dE2F1 results in a severe impairment in cell proliferation, this defect is rescued by the simultaneous loss of the repressor dE2F2, as cell proliferation occurs relatively normally in the absence of both dE2F proteins. We found that the combined inactivation of dE2F1 and dE2F2 had no significant effect on the increased rate of cell division of Hippo pathway mutant cells. In striking contrast, inappropriate proliferation of cells that failed to exit the cell cycle was efficiently blocked. Furthermore, our data suggest that such inappropriate proliferation was primarily dependent on the activator, de2f1, as loss of de2f2 was inconsequential. Consistently, Hippo pathway mutant cells had elevated E2F activity and induced dE2F1 expression at a point when wild-type cells normally exit the cell cycle. Thus, we uncovered a critical requirement for the dE2F family during inappropriate proliferation of Hippo pathway mutant cells
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