501 research outputs found

    Use of Cellular Automata Modelling Approaches to Understand Potential Impacts of GM Grasses on Grassland Communities

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    In order to predict the potential unintended ecological impacts of genetically modified (GM) grasses, we must understand how the engineered traits, in this case herbicide resistance, are expressed in an ecological context. It would be a daunting task to experimentally evaluate the full multiplicity of potential pair-wise interactions between GM plants and native plants under a broad variety of actual environmental conditions. We have employed the modelling methodology of cellular automata (CA), where a plant\u27s distribution within a two-dimensional environmental grid is determined by rules relating to phenomena such as seed dispersal, clonal expansion and interactions with adjacent plants. We have used CA simulation to model interactions between GM grasses and the natural environment by describing the plants and the effect of the GM trait in terms of plant functional types. This approach takes the external factors which limit the amount of plant material present in any habitat and classifies them into two categories: (1) stress, defined with regard to the availability of nutrients and (2) disturbance, which refers to the destruction of plant material. The ecological characteristics of all the plants can be described based on three functional types C (competitor), S (stress-tolerator) and R (ruderal) as determined by their quantifiable physiological relationships to stress and disturbance. By ascribing the large number of plant ecological characteristics to a smaller number of functional types the problem, of describing how the engineered trait of herbicide resistance is expressed in an ecological context, becomes tractable

    Estimate of the impact of background particles on the X-Ray Microcalorimeter Spectrometer on IXO

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    We present the results of a study on the impact of particles of galactic (GCR) and solar origin for the X-ray Microcalorimeter Spectrometer (XMS) aboard an astronomical satellite flying in an orbit at the second Lagrangian point (L2). The detailed configuration presented in this paper is the one adopted for the International X-Ray Observatory (IXO) study, however the derived estimates can be considered a conservative limit for ATHENA, that is the IXO redefined mission proposed to ESA. This work is aimed at the estimate of the residual background level expected on the focal plane detector during the mission lifetime, a crucial information in the development of any instrumental configuration that optimizes the XMS scientific performances. We used the Geant4 toolkit, a Monte Carlo based simulator, to investigate the rejection efficiency of the anticoincidence system and assess the residual background on the detector.Comment: 18 pages, 9 figure

    Natural based products for cleaning copper and copper alloys artefacts

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    Copper alloys objects can deteriorate their conservation state through irreversible corrosion. Since in the cultural heritage field every artefact is unique and any loss irreplaceable, solutions for conservation are needed. Hence, there is the necessity to stop the corrosion process with a suitable cleaning and conservation process to avoid further degradation processes without changing its morphological aspect. Chelating solutions are commonly used in chemical cleaning, mainly sodium salts of ethylenediaminetetraacetic acid (EDTA). However, it is resistant to water purification procedures and is not biodegradable. The goal of this study was to see if applying an ecologically friendly chelating agent as an alternative to EDTA cleaning procedures for cultural heritage was suitable. In this study were chosen six natural-based chelators that could be a new green non-toxic alternative to EDTA in corrosion-inhibiting properties. They were tested for cleaning copper artefacts exposed to atmospheric environment in polluted areas. The study considered four amino acids, a glucoheptonate (CSA) and an industrial green chelator (GLDA). The effectiveness was tested on corrosion copper compounds and on laboratory corroded copper sheets. Finally, the cleaning efficacy was tested on four Roman coins and a modern copper painting. To define the cleaning efficacy, surface analytical investigations have been carried out by means ICP-OES, UV-VIS, µ-Raman, spectro-colorimetry, XRD and FTIR. Among the amino acids, alanine was the most effective, showing an unaltered noble patina and a good effective copper recovery from corrosion patinas

    Substance abuse in first-episode schizophrenic patients: a retrospective study

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    Several studies suggest a high comorbidity of substance abuse and schizophrenia, associated with higher frequency of relapse, more positive symptoms and depression, cognitive impairment, poorer outcome and treatment response. A high incidence of substance abuse is also observed in first-episode patients. Among patients with substance abuse, the onset precedes the onset of psychosis of several years in most cases. All the patients with a first episode of schizophrenia, at first admission to the Psychiatric Service of Diagnosis and Treatment of Ospedale Maggiore of Milan during the years 1990 to 2004, have been included in our study. The clinical evaluation has been obtained considering the following items of Brief Psychiatric Rating Scale (BPRS): conceptual disorganization, depressed mood, hostility, hallucinations, unusual content of thought. The results showed that 34.7% of first-episode schizophrenic patients had a lifetime history of substance abuse. The age of onset of schizophrenia is significantly lower for drug abusers than for patients without any type of abuse and for alcohol abusers (p < 0.005). In multi drug abusers, cannabis resulted the most frequently used (49%), followed by alcohol (13%), and cocaine (4%). Substance abusers have obtained a significant higher score in "thought disturbance" item (p < 0.005) and in "hostility" item (p < 0.005) compared to non substance abusers. Non drug abusers showed lower mean scores of "hostility" item compared to cocaine abusers and multi drug abusers (p < 0.005). Our findings seem to indicate that substance abuse in the early course of illness determines an earlier onset of schizophrenia and increases severity of some psychotic symptoms like "hallucination" and "unusual content of thought". Therefore persons incurring a risk of schizophrenia may be warned of the possible relation between substances and psychosis and have to be counselled against the use of them

    Seismic analysis of Fujian Hakka Tulous

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    The overall earthquake response of Hakka Tulous, traditional earth constructions of the Fujian Province (China) and listed among the UNESCO World Heritage buildings, is investigated. Non-linear static analysis (pushover) with the equivalent frame approach is used. Although some rough approximations are assumed, this approach is well suited to model complex masonry structures, like Tulous. In fact, nonlinear analysis implemented by finite elements or by discrete elements would involve complex models hard to converge and needing long computational time. After carrying out seismic analysis of a Tulou prototype, its failure modes and overall seismic response were evaluated. The Tulou has shown to have good earthquake resistance with respect to the maximum seismic action that can be expected in the Fujian Province

    Emozioni e pensiero organizzativo

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    How to improve compliance with protective health measures during the covid-19 outbreak. Testing a moderated mediation model and machine learning algorithms

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    In the wake of the sudden spread of COVID-19, a large amount of the Italian population practiced incongruous behaviors with the protective health measures. The present study aimed at examining psychological and psychosocial variables that could predict behavioral compliance. An online survey was administered from 18–22 March 2020 to 2766 participants. Paired sample t-tests were run to compare efficacy perception with behavioral compliance. Mediation and moderated mediation models were constructed to explore the association between perceived efficacy and compliance, mediated by self-efficacy and moderated by risk perception and civic attitudes. Machine learning algorithms were trained to predict which individuals would be more likely to comply with protective measures. Results indicated significantly lower scores in behavioral compliance than efficacy perception. Risk perception and civic attitudes as moderators rendered the mediating effect of self-efficacy insignificant. Perceived efficacy on the adoption of recommended behaviors varied in accordance with risk perception and civic engagement. The 14 collected variables, entered as predictors in machine learning models, produced an ROC area in the range of 0.82–0.91 classifying individuals as high versus low compliance. Overall, these findings could be helpful in guiding age-tailored information/advertising campaigns in countries affected by COVID-19 and directing further research on behavioral compliance

    Monte-Carlo Simulations of the Suzaku-XRS Residual Background Spectrum

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    Cryogenic micro-calorimeters are suitable to detect small amounts of energy deposited by electromagnetic and nuclear interactions, which makes them attractive in a variety of applications on ground and in space. The only X-ray microcalorimeter that operated in orbit to date is the X-Ray Spectrometer on-board of the Japanese Suzaku satellite. We discuss the analysis of the components of its residual background spectrum with the support of Monte-Carlo simulations

    La Rete Sismica Mobile del Centro Nazionale Terremoti

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    Il monitoraggio sismico e vulcanico del territorio nazionale rappresenta uno dei principali compiti istituzionali dell’Istituto Nazionale di Geofisica e Vulcanologia (INGV). L’INGV svolge tale importante funzione attraverso la gestione e la manutenzione di reti sismiche di diversa tipologia e a differente scala che consentono di monitorare il territorio nazionale in tempo reale. Tre sale di sorveglianza, una sismica presso la sede centrale di Roma e due vulcaniche presso la Sezione di Catania e l’Osservatorio Vesuviano di Napoli, con personale qualificato in turno H24, consentono di elaborare e comunicare tempestivamente al Dipartimento della Protezione Civile Nazionale (DPC) e alle sue strutture regionali eventuali stati di allarme e il livello dell’emergenza. Il Centro Nazionale Terremoti (CNT) è la sezione dell’INGV preposta al monitoraggio sismico del territorio italiano ed interviene in questo importante servizio attraverso la gestione e la manutenzione della Rete Sismica Nazionale (RSN) in collaborazione con le altre sedi dell’INGV dislocate sul territorio e con gli uffici tecnici locali. Competenza del CNT è anche la rete sismica euro-mediterranea (MedNet): una rete di stazioni sismiche a larga banda dislocate nei Paesi che circondano il Mediterraneo in condivisione con molti istituti geofisici. Negli ultimi anni tali reti sono cresciute sia come numero di stazioni che come tecnologia, consentendo di controllare in maniera estesa lo spettro di frequenze emesse dalla sorgente sismica e la ciclicità delle strutture sismogenetiche. In alcune aree del territorio nazionale l’alta densità di tali reti sismiche rende possibile una soglia di detezione degli eventi molto bassa e localizzazioni di elevata precisione che permettono di associare la micro-sismicità alle strutture sismo-genetiche. Tuttavia questo non è tecnicamente ed economicamente possibile in maniera omogenea su tutto il territorio nazionale. Per tale motivo si fa spesso ricorso all’uso di reti temporanee in esperimenti mirati allo studio di aree a peculiare rischio sismico e vulcanico o, in caso di forti terremoti, per aumentare la densità della rete già presente e migliorare il monitoraggio in real-time in modo tale da analizzare con maggior dettaglio l’evoluzione della sequenza. Unità specializzate nella gestione di reti sismologiche temporanee sono presenti in diverse sedi dell’INGV. Esse lavorano in completa autonomia sul territorio di competenza ma sono in grado di realizzare un buon livello di sinergia là dove esperimenti ed emergenze sismiche richiedano una stretta collaborazione. La struttura più grande, sia come numero di strumenti a disposizione (più di 200 tra digitalizzatori e sensori) che come personale impegnato, è la Rete Sismica Mobile (RSM) del CNT che è organizzata in modo da rendere possibile l’impiego della strumentazione in più esperimenti mantenendo una quota di strumenti riservata per gli interventi di emergenza. In questo rapporto tecnico presentiamo la struttura organizzativa ed operativa della RSM del CNT, la strumentazione in uso presso di essa e le diverse configurazioni possibili per le stazioni sismometriche temporanee con l’obiettivo di fornire un manuale d’uso ai ricercatori, tecnologi e tecnici che si interfacciano con la RSM, sia durante l’attività scientifica ordinaria (esperimenti di sismica passiva e attiva) che straordinaria (emergenze sismiche)
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