4,557 research outputs found

    Is the source-sink relationship in transplanted rice receiving deep-placed urea supergranules dependent upon the geometry of transplanting?

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    Deep placement of urea supergranules in wetland rice (Oryza sativa L.) or correct urea band application enables to protect nitrogen (N) from various loss mechanisms, but recovering of fertilizer N by plants depends upon geometric and agronomic factors. The objective of this study was to characterize the diffusion of ammoniacal N from the two urea sources, point or line application, in a typical paddy soil. A model of ammonia diffusion was developed for the two geometries. The relation between the N application rate and the transplanting geometry was studied in two fields using probes attached to urea supergranule of different mass (2 and 4 g). The transplanting pattern was adapted for obtaining 58 or 116 kg N ha(-1) in the 4 g application. The ammoniacal nitrogen concentration was compared to the diffusion model prediction. The values of the diffusion coefficient were found to be 1.160 and 1.107 cm(2) d(-1). Ammonia disappearance below 10 mmol L-1 did not follow the same kinetics in the two treatments corresponding to 4 g application. Relative to the 2 g treatment, root ammonia uptake in the 4 g treatment was delayed and slowed in the classical geometry of 20 cm x 20 cm (116 kg N ha(-1)) when it was mainly delayed in the geometry provided with 58 kg N ha(-1). This manipulation of the source-sink relationship enables to foresee possibilities for the development of new fertilizers adapted to wetland rice cultivation

    Analisi dinamiche in tensioni efficaci con il codice "SCOSSA"

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    L’incremento di pressioni interstiziali indotto da azioni sismiche in depositi sabbio-limosi determina la progressiva riduzione delle tensioni efficaci e di conseguenza della rigidezza e della resistenza dei terreni, fino a condurre alla completa liquefazione. Un metodo sviluppato per la stima di tale incremento si basa su un parametro semi-empirico, detto ‘parametro di danno’, che consente di applicare direttamente i risultati di prove cicliche di laboratorio per predire l’incremento di pressione interstiziale generato in sito dall’azione sismica. Tale procedura, implementata all’interno di un codice di calcolo non lineare, consente di effettuare analisi monodimensionali in tensioni efficaci senza adottare sofisticati modelli costitutivi del terreno. L’applicazione ad un argine danneggiato dal terremoto emiliano del 2012 ha consentito di evidenziare fenomeni di degradazione ciclica degli strati sabbiosi profondi che non sarebbe stato possibile osservare con le tradizionali analisi in tensioni totali

    Bimodality in low-luminosity E and S0 galaxies

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    Stellar population characteristics are presented for a sample of low-luminosity early-type galaxies (LLEs) in order to compare them with their more luminous counterparts. Long-slit spectra of a sample of 10 LLEs were taken with the ESO New Technology Telescope, selected for their low luminosities. Line strengths were measured on the Lick standard system. Lick indices for these LLEs were correlated with velocity dispersion (σ), alongside published data for a variety of Hubble types. The LLEs were found to fall below an extrapolation of the correlation for luminous ellipticals and were consistent with the locations of spiral bulges in plots of line strengths versus σ. Luminosity weighted average ages, metallicities and abundance ratios were estimated from χ2 fitting of 19 Lick indices to predictions from simple stellar population models. The LLEs appear younger than luminous ellipticals and of comparable ages to spiral bulges. These LLEs show a bimodal metallicity distribution, consisting of a low-metallicity group (possibly misclassified dwarf spheroidal galaxies) and a high-metallicity group (similar to spiral bulges). Finally, they have low α-element to iron peak abundance ratios indicative of slow, extended star formation

    1D Seismic Response Analysis of Soil-building Systems Including Failure Shear Mechanisms

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    Modelling of soil shear rupture due to an earthquake is not generally implemented in the common codes for 1D seismic response analysis. It requires the use of advanced plasticity-based constitutive models of soil, that are often neglected in practice. A good balance between simplicity and reliability can be achieved with methods based on simplified formulations of the mathematical equations and of the constitutive models. The paper presents a computer code based on this philosophy conceived, addressed and optimised to reliably model both the 'transient' seismic response ('stick' mode) and the permanent deformation mechanisms accounting for the coupled effects of deformability and strength ('slip' mode). The code can be adopted to evaluate the seismic performance of different geotechnical systems that can be reasonably approximated to a 1D problem. In the paper, the code is applied to model a soft-storey failure occurred in a framed structure heavily damaged during a strong-motion earthquake

    BSM physics at the LHeC and the FCC-he

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    Electron-proton (e-p) colliders are an ideal laboratory to study common features of electron and quarks with production via electroweak bosons, leptoquarks, multi-jet final states and very forward physics, due to their impressive pseudorapidity coverage. In addition to these physics cases, there exist a broad Beyond the Standard Model (BSM) program aimed at exploring the capabilities of the LHeC [1] and FCC-he [2] for several New Physics scenarios. Although their centre-of-mass energy is down with respect to a pp collider by a factor of √Ep/Ee ∼ 10 (30) for the LHeC (FCC-he), they can be an invaluable tool to characterize BSM physics hints at ee and pp machines. The aim of this talk is to provide, on behalf of the BSM e-p Working Group, an overview of the aforementioned BSM program, by briefly summarizing the existing studies and reporting on the most recent progress. We expect that the ample scope in terms of NP models to be tested would enhance the synergies between the BSM and e-p communities

    Physiological changes induced by either pre- or post-veraison deficit irrigation in 'Merlot' vines grafted on two different rootstocks

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    Reduced summer precipitations and higher evapotranspiration due to elevated temperatures are expected to enhance the impact of water deficit in modern viticulture. We investigated the effect of the timing of deficit irrigation on vine growth, water relations, yield and grape composition in 'Merlot' vines grafted on 1103P or SO4. In both years we did not measure any differences between rootstocks in stem water potential (SWP). Vegetative growth was decreased by the restriction of irrigation between fruit set and veraison. Stomatal conductance (gs) was affected by irrigation, but not by the rootstock. During the pre-veraison period there was a clear inverse relationship between gs and SWP. The leaf non photochemical quenching readily responded to the stress imposed on 1103P rootstock. Vines subjected to water deficit between fruit set and veraison produced smaller berries than well irrigated ones, whereas deficit applied after veraison determined about 10 % differences in berry weight. The highest and lowest values of pH and TA were measured in berries from pre-veraison deficit irrigated vines grafted on both 1103P and SO4, respectively

    Emission Line Galaxies and Active Galactic Nuclei in WINGS clusters

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    We present the analysis of the emission line galaxies members of 46 low redshift (0.04 < z < 0.07) clusters observed by WINGS (WIde-field Nearby Galaxy cluster Survey, Fasano et al. 2006). Emission line galaxies were identified following criteria that are meant to minimize biases against non-star forming galaxies and classified employing diagnostic diagrams. We have examined the emission line properties and frequencies of star forming galaxies, transition objects and active galactic nuclei (AGNs: LINERs and Seyferts), unclassified galaxies with emission lines, and quiescent galaxies with no detectable line emission. A deficit of emission line galaxies in the cluster environment is indicated by both a lower frequency with respect to control samples, and by a systematically lower Balmer emission line equivalent width and luminosity (up to one order of magnitude in equivalent width with respect to control samples for transition objects) that implies a lower amount of ionised gas per unit mass and a lower star formation rate if the source is classified as Hii region. A sizable population of transition objects and of low-luminosity LINERs (approx. 10 - 20% of all emission line galaxies) is detected among WINGS cluster galaxies. With respect to Hii sources they are a factor of approx. 1.5 more frequent than (or at least as frequent as) in control samples. Transition objects and LINERs in cluster are most affected in terms of line equivalent width by the environment and appear predominantly consistent with "retired" galaxies. Shock heating can be a possible gas excitation mechanism able to account for observed line ratios. Specific to the cluster environment, we suggest interaction between atomic and molecular gas and the intracluster medium as a possible physical cause of line-emitting shocks.Comment: Astronomy and Astrophysics, accepte

    Robot Assistive Therapy Strategies for Children with Autism

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    Background: Autism spectrum disorder (ASD) is a category of neurodevelopmental disorder characterized by persistent deficits in social communication and social interaction across multiple contexts as well as restricted, repetitive patterns of behaviour, interests, or activities. Social robots offer clinicians new ways to interact and work with people with ASD. Robot-Assisted Training (RAT) is a growing body of research in HRI, which studies how robots can assist and enhance human skills during a task-centred interaction. RAT systems have a wide range of application for children with ASD. Aims: In a pilot RCT with an experimental group and a control group, research aims will be: to assess group differences in repetitive and maladaptive behaviours (RMBs), affective states and performance tasks across sessions and within each group; to assess the perception of family relationships between two groups before and post robot interaction; to develop a robotic app capable to run Raven’s Progressive Matrices (RPM), a test typically used to measure general human intelligence and to compare the accuracy of the robot to capture the data with that run by psychologists. Material and Methods: Patients with mild or moderate level of ASD will be enrolled in the study which will last 3&nbsp;years. The sample size is: 60 patients (30 patients will be located in the experimental group and 30 patients will be located in the control group) indicated by an evaluation of the estimated enrolment time. Inclusion criteria will be the following: eligibility of children confirmed using the Autism Diagnostic Observation Schedule −2; age ≥ 7&nbsp;years; clinician judgment during a clinical psychology evaluation; written parental consent approved by the local ethical committee. The study will be conducted over 10&nbsp;weeks for each participant, with the pretest and post test conducted during the first and last weeks of the study. The training will be provided over the intermediate eight weeks, with one session provided each week, for a total of 8 sessions. Baseline and follow-up evaluation include: socioeconomic status of families will be assessed using the Hollingshead scale; Social Communication Questionnaire (SCQ) will be used to screen the communication skills and social functioning in children with ASD; Vineland Adaptive Behavior Scale, 2nd edition (VABS) will be used to assess the capabilities of children in dealing with everyday life; severity and variety of children’s ripetitive behaviours will be also assessed using Repetitive Behavior Scale-Revised (RBS-R). Moreover, the perception of family relationships assessment will be run by Portfolio for the validation of parental acceptance and refusal (PARENTS). Expected Results: 1) improbe communication skills; 2) reduced repetitive and maladaptive behaviors; 3) more positive perception of family relationships; 4) improved performance. Conclusions: Robot-Assisted Training aims to train and enhance user (physical or cognitive) skills, through the interaction, and not assist users to complete a task thus a target is to enhance user performance by providing personalized and targeted assistance towards maximizing training and learning effects. Robotics systems can be used to manage therapy sessions, gather and analyse data and like interactions with the patient and generate useful information in the form of reports and graphs, thus are a powerful tool for the therapist to check patient’s progress and facilitate diagnosis
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