1,934 research outputs found

    Glacio and hydro-isostasy in the Mediterranean Sea: Clark’s zones and role of remote ice sheets

    Get PDF
    Solving the sea-level equation for a spherically symmetric Earth we study the relative sea-level curves in the Mediterranean Sea in terms of Clark’s zones and we explore their sensitivity to the time-history of Late-Pleistocene ice aggregates. Since the Mediterranean is an intermediate field region with respect to the former ice sheets, glacio- and hydro-isostasy both contribute to sea-level variations throughout the Holocene. In the bulk of the basin, subsidence of the sea floor results in a monotonous sea-level rise, whereas along continental margins water loading produces the effect of «continental levering», which locally originates marked highstands followed by a sea-level fall. To describe such peculiar pattern of relative sea-level in this and other mid-latitude closed basins we introduce a new Clark’s zone (namely, Clark’s zone VII). Using a suite of publicly available ice sheet chronologies, we identify for the first time a distinct sensitivity of predictions to the Antarctic ice sheet. In particular, we show that the history of mid to Late Holocene sea-level variations along the coasts of SE Tunisia may mainly reflect the melting of Antarctica, by a consequence of a mutual cancellation of the effects from the Northern Hemisphere ice-sheets at this specific site. Ice models incorporating a delayed melting of Antarctica may account for the observations across the Mediterranean, but fail to reproduce the SE Tunisia highstand

    Elastoplastic Damaging Model for Adhesive Anchor Systems. II: Numerical and Experimental Validation

    Get PDF
    This paper presents the numerical and experimental validation of the analytical elastoplastic damaging model proposed in the companion paper (Part I). The validation was carried out by describing the pullout failure of epoxy adhesive anchors. Pullout tests were simulated numerically and performed experimentally. Several specimens made of a rebar embedded in a hardened concrete cylinder by means of polyester resin were tested. Conventional strain gauges and acoustic emission (AE) sensors were used to evaluate the structural response of the system and to monitor the onset and progression of structural damage, respectively. The parametric analysis and the moment tensor analysis of the AE data were used to discriminate among different sources of damage. The results show the ability of the model to predict the response of the anchors and the suitability of the AE method to monitor damage onset and propagation and to discriminate among different source of damage

    Clinical case seminar - Hypogonadotropic hypogonadism as a presenting feature of late-onset X-linked adrenal hypoplasia congenita

    Get PDF
    Mutations in the orphan nuclear receptor DAX-1 cause X-linked adrenal hypoplasia congenita. Affected boys usually present with primary adrenal failure in early infancy or childhood. Impaired sexual development because of hypogonadotropic hypogonadism becomes apparent at the time of puberty. We report adult-onset adrenal hypoplasia congenita in a patient who presented with hypogonadism at 28 yr of age. Although he had no clinical evidence of adrenal dysfunction, compensated primary adrenal failure was diagnosed by biochemical testing. Semen analysis showed azoospermia, and he did not achieve fertility after 8 months of treatment with gonadotropins. A novel Y380D DAX-1 missense mutation, which causes partial loss of function in transient gene expression assays, was found in this patient. This case demonstrates that partial loss-of-function mutations in DAX1 can present with hypogonadotropic hypogonadism and covert adrenal failure in adulthood. Further, an important role for DAX-1 in spermatogenesis in humans is confirmed, supporting findings in the Dax1 (Ahch) knockout mouse

    Creep, Relaxation and Viscosity Properties for Basic Fractional Models in Rheology

    Full text link
    The purpose of this paper is twofold: from one side we provide a general survey to the viscoelastic models constructed via fractional calculus and from the other side we intend to analyze the basic fractional models as far as their creep, relaxation and viscosity properties are considered. The basic models are those that generalize via derivatives of fractional order the classical mechanical models characterized by two, three and four parameters, that we refer to as Kelvin-Voigt, Maxwell, Zener, anti-Zener and Burgers. For each fractional model we provide plots of the creep compliance, relaxation modulus and effective viscosity in non dimensional form in terms of a suitable time scale for different values of the order of fractional derivative. We also discuss the role of the order of fractional derivative in modifying the properties of the classical models.Comment: 41 pages, 8 figure

    Post glacial readjustment, sea level variations, subsidence and erosion along the Italian coasts

    Get PDF
    Ongoing sea level variations and vertical land movements measured by tide gauges and continuous GPS stations along the Italian coasts stem from several factors acting on different spatiotemporal scales. Conversely to tectonics and anthropogenic effects, which are characterized by a heterogeneous signal, the adjustment of solid Earth and geoid to the melting of the late– Pleistocene ice sheets results in a smooth long–wavelength pattern of sea level variation and vertical deformation across the Mediterranean, mostly driven by the melt water load added to the basin. In this work we define upper and lower bounds of the effects of glacial isostatic adjustment (GIA) on current sea level variations and vertical ground movements along the coasts of Italy. For plausible mantle viscosity profiles we explore to what extent the spatial variability of observed rates may be attributed to delayed isostatic recovery of both solid Earth and geoid. In addition, we show that long–wavelength patterns of sea level change are tuned by the effects of GIA, and that coastal retreat in Italy is broadly correlated with the expected ongoing rates of post–glacial sea level variations

    Sea-level rise along the Emilia-Romagna coast (Northern Italy) in 2100: scenarios and impacts

    Get PDF
    As a consequence of climate change and land subsidence, coastal zones are directly impacted by sea-level rise. In some particular areas, the effects on the ecosystem and urbanisation are particularly enhanced. We focus on the Emilia-Romagna (E-R) coastal plain in Northern Italy, bounded by the Po river mouth to the north and by the Apennines to the south. The plain is  ∼ 130 km long and is characterised by wide areas below mean sea level, in part made up of reclaimed wetlands. In this context, several morphodynamic factors make the shore and back shore unstable. During next decades, the combined effects of land subsidence and of the sea-level rise as a result of climate change are expected to enhance the shoreline instability, leading to further retreat. The consequent loss of beaches would impact the economy of the region, which is tightly connected with tourism infrastructures. Furthermore, the loss of wetlands and dunes would threaten the ecosystem, which is crucial for the preservation of life and the environment. These specific conditions show the importance of a precise definition of the possible local impacts of the ongoing and future climate variations. The aim of this work is the characterisation of vulnerability in different sectors of the coastal plain and the recognition of the areas in which human intervention is urgently required. The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) sea-level scenarios are merged with new high-resolution terrain models, current data for local subsidence and predictions of the flooding model in_CoastFlood in order to develop different scenarios for the impact of sea-level rise projected to year 2100. First, the potential land loss due to the combined effect of subsidence and sea-level rise is extrapolated. Second, the increase in floodable areas as a result of storm surges is quantitatively determined. The results are expected to support the regional mitigation and adaptation strategies designed in response to climate change

    The Metacognitions about Binge Eating Questionnaire (MBEQ): investigation of the association between specific metacognitions and Binge Eating Disorder

    Get PDF
    Literature suggested that metacognitions are involved in eating problems and may be relevant to the understanding of Binge Eating Disorder (BED). The goal of the current studies was to develop the first self-report instrument on metacognitions about binge eating. In Study 1, a community sample completed the Metacognitions about Binge Eating Questionnaire (MBEQ); an Exploratory Factor Analysis (EFA) was performed. In study 2, a community sample completed the MBEQ and measures assessing severity of binge eating, irrational food beliefs, anxiety, depression, impulsiveness. A Confirmatory Factor Analysis (CFA) was performed. Concurrent and incremental validity were assessed. In study 3, a clinical sample of participants with a diagnosis of BED completed the MBEQ and other measures. Bivariate correlational analysis and hierarchical linear regression were performed. Participants from the general population and participants with a diagnosis of BED were compared. EFA and CFA supported a two-factor solution consisting of positive and negative metacognitions about binge eating. Concurrent and incremental validity were acceptable. The metacognitions factors correlated positively with anxiety, depression, irrational food beliefs, impulsiveness in the community sample, and anxiety, irrational food beliefs, impulsiveness in clinical sample. The metacognitions factors contributed to the prediction of binge eating disorders symptoms, in community and clinical samples, over and above age, gender, impulsiveness, anxiety, depression, irrational food beliefs. The MBEQ possesses good psychometric properties and appears a reliable and valid measure of positive and negative metacognitions about binge eating. Metacognitions about binge eating could be a therapeutic target to reduce the severity of binge eating episodes

    3D Graphic for promoting Cultural Heritages: the example of Petraro archaeological site in Villasmundo (Melilli-Siracusa, Sicily)

    Get PDF
    This work is part of a wider project aimed to studying and promoting the archeological area of “Petraro” in Villasmundo (Melilli – SR), in collaboration with LegambienteMelilli – Sezione TimpaDdieri. Explored for the first time in 1967 by the archeologist Giuseppe Voza[1], the site exhibits the remains of an interesting prehistoric fortified village dated at XVI – XV sec. B. C.; this structure has been evaluated as an unicum in Sicily for its architectonical characteristics and archeological records[2].Unfortunately, for many years, the area has been abandoned and made inaccessible to visitors, causing an important degrade of the site. In the last decade, the use of virtual reconstruction of Cultural Heritage has become a recurring custom for visualization of several features of an archaeological site[3, 4]. In particular, 3D computer graphics have been interpreted as a useful tool for the understanding of prehistoric remains[5], often characterized by bad preservation and absence of documentary sources. For aforementioned, the aim of this paper is to present the results of a virtual model of the prehistoric village of Petraro and the archeological records recovered in the site. In this context, 3D modeling could clarify some features of the area and offer a new tool for promoting this archeological site

    Depriving Mice of Sleep also Deprives of Food.

    Get PDF
    Both sleep-wake behavior and circadian rhythms are tightly coupled to energy metabolism and food intake. Altered feeding times in mice are known to entrain clock gene rhythms in the brain and liver, and sleep-deprived humans tend to eat more and gain weight. Previous observations in mice showing that sleep deprivation (SD) changes clock gene expression might thus relate to altered food intake, and not to the loss of sleep per se. Whether SD affects food intake in the mouse and how this might affect clock gene expression is, however, unknown. We therefore quantified (i) the cortical expression of the clock genes Per1, Per2, Dbp, and Cry1 in mice that had access to food or not during a 6 h SD, and (ii) food intake during baseline, SD, and recovery sleep. We found that food deprivation did not modify the SD-incurred clock gene changes in the cortex. Moreover, we discovered that although food intake during SD did not differ from the baseline, mice lost weight and increased food intake during subsequent recovery. We conclude that SD is associated with food deprivation and that the resulting energy deficit might contribute to the effects of SD that are commonly interpreted as a response to sleep loss

    Democracy Matters: Lessons from the 2015 Citizens' Assemblies on English Devolution

    Get PDF
    The Citizens’ Assembly pilots on local democracy and devolution were the first of their kind in the United Kingdom. Organised by Democracy Matters — an alliance of university researchers and civil society organisations led by Professor Matthew Flinders — and funded by the UK’s Economic and Social Research Council, the Assemblies took place in Southampton and Sheffield towards the end of 2015
    corecore