285 research outputs found

    Performance Analysis of Tomographic Methods against Experimental Contactless Multistatic Ground Penetrating Radar

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    Ground-penetrating radar (GPR) technology for underground exploration consists of the transmission of an electromagnetic signal in the ground for sensing the presence of buried objects. While monostatic or bistatic configurations are usually adopted, a limited number of multistatic GPR systems have been proposed in the scientific literature. In this article, we investigate the recovery performance of a specific and unconventional contactless multistatic GPR system, designed at the Georgia Institute of Technology for the subsurface imaging of antitank and antipersonnel plastic mines. In particular, for the first time, tomographic approaches are tested against this experimental multistatic GPR system, while most GPR processing in the scientific literature processes multimonostatic experimental data sets. First, by mimicking the system at hand, an accurate theoretical as well as numerical analysis is performed in order to estimate the data information content and the performance achievable. Two different tomographic linear approaches are adopted, i.e., the linear sampling method and the Born approximation (BA) method, this latter enhanced by means of the compressive sensing (CS) theoretical framework. Then, the experimental data provided by the Georgia Institute of Technology are processed by means of a multifrequency CS- and BA-based method, thus generating very accurate 3D maps of the investigated underground scenario

    An integrated genetic-demographic model to unravel the origin of genetic structure in European eel (<i>Anguilla anguilla</i> L.)

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    The evolutionary enlightened management of species with complex life cycles often requires the development of mathematical models integrating demographic and genetic data. The genetic structure of the endangered European eel (Anguilla anguilla L.) has been thoroughly analyzed in several studies in the past years. However, the interpretation of the key demographic and biologic processes that determine the observed spatio-temporal genetic structure has been very challenging owing to the complex life cycle of this catadromous species. Here, we present the first integrated demographic-genetic model applied to the European eel that explicitly accounts for different levels of larval and adult mixing during oceanic migrations and allows us to explore alternative hypotheses on genetic differentiation. Our analyses show that (i) very low levels of mixing occurring during larval dispersal or adult migration are sufficient to erase entirely any genetic differences among sub-populations; (ii) small-scale temporal differentiation in recruitment can arise if the spawning stock is subdivided in distinct reproductive groups; and (iii) the geographic differentiation component might be overestimated if a limited number of temporal recruits are analyzed. Our study can inspire the scientific debate on the interpretation of genetic structure in other species characterized by complex life cycle and long-range migrations

    Psychosocial Risk Factors and Psychopathological Outcomes: Preliminary Findings in Italian Pregnant Women

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    The perinatal period may represent a particularly challenging time for expecting parents. Previous studies have highlighted an association between several perinatal risk conditions (e.g., childhood maltreatment, poor social support, and stress levels) and the development of psychopathological symptoms in pregnant women, especially depression symptoms. The current study examined the effects of psychosocial risk factors (childhood maltreatment, poor social support, and stressful events) on anxiety, depression, perceived stress, irritability/anger, relationship problems, psychosomatic symptoms, specific physiological problems, and addiction/at-risk behaviors. Sixty-one pregnant women (age range = 24–45) participating in a larger study completed questionnaires about childhood maltreatment (CECA Q.), Maternity Social Support Scale (MSSS), questionnaire on stressful events, and the Perinatal Assessment of Maternal Affectivity (PAMA) during their pregnancy. Results from regression analysis indicated that the presence of childhood maltreatment predicted elevated depressive symptoms, elevated irritability and anger, and elevated relationship problems. Further, stressful events in the year prior to pregnancy predicted elevated psychosomatic symptoms during pregnancy. No other significant associations were found. In this study, traumatic childhood events were strongly associated with mental health symptoms during pregnancy. This is an important finding that suggests the importance of screening and targeting psychotherapeutic interventions for vulnerable women during pregnancy

    Higher probability of compound flooding from precipitation and storm surge in Europe under anthropogenic climate change

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    In low-lying coastal areas, the co-occurrence of high sea level and precipitation resulting in large runoff may cause compound flooding (CF). When the two hazards interact, the resulting impact can be worse than when they occur individually. Both storm surges and heavy precipitation, as well as their interplay, are likely to change in response to global warming. Despite the CF relevance, a comprehensive hazard assessment beyond individual locations is missing, and no studies have examined CF in the future. Analyzing co-occurring high sea level and heavy precipitation in Europe, we show that the Mediterranean coasts are experiencing the highest CF probability in the present. However, future climate projections show emerging high CF probability along parts of the northern European coast. In several European regions, CF should be considered as a potential hazard aggravating the risk caused by mean sea level rise in the future

    An Ion Exchange Membrane Crystallisation reactor for Magnesium recovery from brines

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    CrIEM technology is a novel ion exchange application that allows reactive crystallization for separation of valuable species (e.g. Mg from brines) with a large flexibility in the choice of reactants

    Demonstrating the impact of a distributed leadership approach in higher education

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    © 2017 Association for Tertiary Education Management and the LH Martin Institute for Tertiary Education Leadership and Management. Higher education is under pressure to advance from a singular focus on assessment of outputs (measurements) to encompass the impact (influence) of initiatives across all aspects of academic endeavour (research, learning and teaching, and leadership). This paper focuses on the implications of this shift for leadership in higher education. Demonstrating the impact of leadership in higher education requires taking a step beyond measuring the skills, behaviours, and achievements of individual leaders to demonstrating how universities can evaluate the impact of actions taken to build leadership capacity across the institution. The authors extend the outcome of empirical research into how a distributed leadership approach can be enabled and evaluated in Australian higher education–to analyse the effectiveness of these processes for both measuring output and assessing the impact and influence of practice

    No apparent genetic bottleneck in the demographically declining European eel using molecular genetics and forward-time simulations

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    No apparent genetic bottleneck in the demographically declining European eel using molecular genetics and forward-time simulations

    Transcranial cortico-cortical paired associative stimulation (ccPAS) over ventral premotor-motor pathways enhances action performance and corticomotor excitability in young adults more than in elderly adults

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    Transcranial magnetic stimulation (TMS) methods such as cortico-cortical paired associative stimulation (ccPAS) can increase the strength of functional connectivity between ventral premotor cortex (PMv) and primary motor cortex (M1) via spike timing-dependent plasticity (STDP), leading to enhanced motor functions in young adults. However, whether this STDP-inducing protocol is effective in the aging brain remains unclear. In two groups of young and elderly healthy adults, we evaluated manual dexterity with the 9-hole peg task before and after ccPAS of the left PMv-M1 circuit. We observed that ccPAS enhanced dexterity in young adults, and this effect was anticipated by a progressive increase in motor-evoked potentials (MEPs) during ccPAS administration. No similar effects were observed in elderly individuals or in a control task. Across age groups, we observed that the magnitude of MEP changes predicted larger behavioral improvements. These findings demonstrate that left PMv-to-M1 ccPAS induces functionally specific improvements in young adults' manual dexterity and an increase in corticomotor excitability, but altered plasticity prevents the effectiveness of ccPAS in the elderly

    A pilot-plant for the selective recovery of magnesium and calcium from waste brines

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    The problem of brines disposal has raised great interest towards new strategies for their valorisation through the recovery of minerals or energy. As an example, the spent brine from ion exchange resins regeneration is often discharged into rivers or lakes, thus impacting on the process sustainability. However, such brines can be effectively reconcentrated, after removal of bivalent cations, and reused for the resins regeneration. This work focuses on developing and testing a pilot plant for selective recovery of magnesium and calcium from spent brines exploiting a novel proprietary crystallization unit. This is part of a larger treatment chain for the complete regeneration of the brine, developed within the EU-funded ZERO BRINE project. The pilot crystallizer was tested with the retentate of the nanofiltration unit processing the spent brine from the industrial water production plant of Evides Industriewater B.V. (Rotterdam, The Netherlands). Magnesium and calcium hydroxide were selectively precipitated by adding alkaline solution in two consecutive steps and controlling reaction pH. Performance was assessed in terms of recovery efficiency and purity of produced crystals, observing in most investigated cases a recovery of about 100% and 97% and a purity above 90% and 96%, for magnesium and calcium hydroxide, respectively

    Dextran-curcumin nanoparticles as a methotrexate delivery vehicle: A step forward in breast cancer combination therapy

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    With the aim to effectively deliver methotrexate (MTX) to breast cancer cells, we designed a nanocarrier system (DC) derived from the self-assembly of a dextran-curcumin conjugate prepared via enzyme chemistry with immobilized laccase acting as a solid biocatalyst. Nanoparticles consisted of homogeneously dispersed nanospheres with a mean diameter of 290 nm, as characterized by combined transmission electron microscopy and dynamic light scattering investigations. DC was able to control the MTX release overtime (t1/2 value of 310 min), with cell internalization studies proving its presence inside MCF-7 cytoplasm. Finally, improved MTX efficacy was obtained in viability assays, and attributed to the synergy of curcumin moieties and loaded MTX as underlined by a combination index (CI) < 1
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