1,251 research outputs found

    Galaxy clusters in different dynamical state: a multiband view from MeerKAT and uGMRT

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    Galaxy clusters are the largest gravitationally bound systems in the Universe, they are special laboratories where is it possible to investigate the evolution and the properties of galaxies in different environments, starting from their centre, going out to the virial radius and beyond. The properties of radio galaxies can be related to their environment and its dynamical status: nowdays, understand whether the observed properties of radio galaxies arise at formation (nature scenario), or they are an end-product of physical processes (nurture scenario) coming into play after galaxies have become part of a `group' or a `cluster' is difficult and much debated. We started this work, analyzing a sample of eleven Brightes Cluster Galaxies (BCGs) from ten galaxy clusters in the redshift range 0.2 < z < 0.4. They were selected because of the overlap between the Extended GMRT Radio Halo Survey (EGRHS) and the Cluster Lensing and Supernovae Survey with Hubble (CLASH). The main aim is to examine the radio properties of these galaxies considered `special' because of their position at the very centre of galaxy cluster potential well. In particular, to understand whether the main mechanism responsible for the radio emission, when detected, is mainly due to AGN activity or to Star Formation activity and which is the interplay between the two mechanisms, since both are of fundamental importance for the feedback phenomena

    H2O2 Signature and Innate Antioxidative Profile Make the Difference Between Sensitivity and Tolerance to Salt in Rice Cells

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    Salt tolerance is a complex trait that varies between and within species. H2O2 profiles as well as antioxidative systems have been investigated in the cultured cells of rice obtained from Italian rice varieties with different salt tolerance. Salt stress highlighted differences in extracellular and intracellular H2O2 profiles in the two cell cultures. The tolerant variety had innate reactive oxygen species (ROS) scavenging systems that enabled ROS, in particular H2O2, to act as a signal molecule rather than a damaging one. Different intracellular H2O2 profiles were also observed: in tolerant cells, an early and narrow peak was detected at 5 min; while in sensitive cells, a large peak was associated with cell death. Likewise, the transcription factor salt-responsive ethylene responsive factor 1 (TF SERF1), which is known for being regulated by H2O2, showed a different expression profile in the two cell lines. Notably, similar H2O2 profiles and cell fates were also obtained when exogenous H2O2 was produced by glucose/glucose oxidase (GOX) treatment. Under salt stress, the tolerant variety also exhibited rapid upregulation of K+ transporter genes in order to deal with K+/Na+ impairment. This upregulation was not detected in the presence of oxidative stress alone. The importance of the innate antioxidative profile was confirmed by the protective effect of experimentally increased glutathione in salt-treated sensitive cells. Overall, these results underline the importance of specific H2O2 signatures and innate antioxidative systems in modulating ionic and redox homeostasis for salt stress tolerance

    Analgesia and/or anaesthesia during piglet castration &#8211; part II: practicability of farm protocols, resource efficiency and economic implications

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    Pain alleviation associated with castration of piglets is a debated welfare issue. This study compares practical aspects, resource efficiency and economic implications of two protocols involving both analgesia and anaesthesia compared to a control group: conventional castration without pain relief (CTRL); joint administration of azaperone and meloxicam (AZA-MEL), i.m.; procaine (PROC-MEL), s.c., and meloxicam, i.m. A total number of 356 male piglets (56 L), was involved. Labour, mortality during the lactation period and costs for procedures were analysed. The total amount of labour required for each single male piglet and the risk of recording at least one dead piglet during lactation in litters were significantly higher in AZA-MEL and PROC-MEL groups than in CTRL group (labour: 02:04 and 02:04 vs. 01:18 min, respectively, p <.001; mortality risk: (RR = 1.48; CI 95% = 1.02 12 2.16; p =.029). The cost estimated for the castration of each male piglet in CRTL group was 0.32 \u20ac, whereas was 3.14 \u20ac for AZA-MEL group and 3.30 \u20ac for PROC-MEL group. The results suggest that adopting analgesia and anaesthesia showed notable cost increases for farmers. This might be expected and justifiable when the management is improved to reach a higher standard quality, such as in the case of welfare-friendly surgical castration, but might be questionable when also considering the result of increased piglet mortality in the lactation period.HIGHLIGHTS To use meloxicam + azaperone or + procaine on farm during piglets castration, increases labour of workers by 76.8 and 56.5%, respectively. At the same time, also piglets mortality risk increases by 48% during lactation. Total costs for each male piglet castrated with meloxicam + azaperone or + procaine increased by 3.14 and 3.30 \u20ac, respectively

    Pullulan for advanced sustainable body- and skin-contact applications

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    The present review had the aim of describing the methodologies of synthesis and properties of biobased pullulan, a microbial polysaccharide investigated in the last decade because of its interesting potentialities in several applications. After describing the implications of pullulan in nano-technology, biodegradation, compatibility with body and skin, and sustainability, the current applications of pullulan are described, with the aim of assessing the potentialities of this biopolymer in the biomedical, personal care, and cosmetic sector, especially in applications in contact with skin

    Change point detection in dynamic Gaussian graphical models: the impact of COVID-19 pandemic on the US stock market

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    Reliable estimates of volatility and correlation are fundamental in economics and finance for understanding the impact of macroeconomics events on the market and guiding future investments and policies. Dependence across financial returns is likely to be subject to sudden structural changes, especially in correspondence with major global events, such as the COVID-19 pandemic. In this work, we are interested in capturing abrupt changes over time in the dependence across US industry stock portfolios, over a time horizon that covers the COVID-19 pandemic. The selected stocks give a comprehensive picture of the US stock market. To this end, we develop a Bayesian multivariate stochastic volatility model based on a time-varying sequence of graphs capturing the evolution of the dependence structure. The model builds on the Gaussian graphical models and the random change points literature. In particular, we treat the number, the position of change points, and the graphs as object of posterior inference, allowing for sparsity in graph recovery and change point detection. The high dimension of the parameter space poses complex computational challenges. However, the model admits a hidden Markov model formulation. This leads to the development of an efficient computational strategy, based on a combination of sequential Monte-Carlo and Markov chain Monte-Carlo techniques. Model and computational development are widely applicable, beyond the scope of the application of interest in this work

    Adopting educational robotics and coding to open dialogic spaces in lower secondary education

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    This article explores how the adoption of educational robotics, cloud-based animation software, and simplified visual programming software can provide valuable opportunities for dialogic interaction and learning. The potentialities of this type of activity are often overlooked in dialogic investigations. Based on empirical illustration, we discuss how open-ended educational tasks involving the creation of material-digital artifacts can promote the expression of the students' voices and the emergence of a dialogic space in which both human and non-human Others, as well as chronotropic dynamics and materiality, play a crucial role. To provide a polyphonic account of the dialogical processes detected, we analyzed excerpts from two group interviews with seven lower secondary school students (aged 11-12) and excerpts taken from meetings with their teacher. Our qualitative analysis shows that the technology-mediated activity provided valuable opportunities for opening a dialogic space in which the students could express their own voice in interaction with both human and non-human Others. The material world (including the virtual materiality of computer-generated objects) seems to play a twofold role. First, the resistance of the virtual and material objects can contribute to the opening of a dialogical space between the child and the world; second, the chronotopic relations seem to have an impact on the dialogic learning process. These are valid opportunities for educationally relevant dialogic interaction. They should be cultivated and supported to further advance the pedagogical value of educational robotics and coding.Peer reviewe

    Some aspects of Relativistic Astrometry from within the Solar System

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    In this article we outline the structure of a general relativistic astrometric model which has been developed to deduce the position and proper motion of stars from 1-microarcsecond optical observations made by an astrometric satellite orbiting around the Sun. The basic assumption of our model is that the Solar System is the only source of gravity, hence we show how we modeled the satellite observations in a many-body perturbative approach limiting ourselves to the order of accuracy of (v/c)2(v/c)^2. The microarcsecond observing scenario outlined is that for the GAIA astrometric mission.Comment: 11 pages, 2 figures, accepted by Cel. Me

    Mechanical properties of the most common European woods: a literature review

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    Wood is an orthotropic material used since ancient time. A literature research about the mechanical properties of density, fracture toughness, modulus of elasticity, and Poisson’s ratio has been done to have a broader view on the subject. The publications relating to the topic were found through the two search engines Scopus and Google Scholar that have yielded several papers, including articles and book sections. In general, there is no standardization on the method of analysis carried out on wood, underlining the great difficulty in studying this complex material. The parameter of density has a great variability and needs a deeper investigation; fracture toughness is not always available in literature, not even in the different directions of the wood sample. Interesting is the modulus of elasticity, which provides a correlation with density, especially in longitudinal section but, again, it needs to be studied in detail. The parameter of Poisson’s ratio is provided as single values in three different directions, but mainly for softwood. All the parameters require a more in-depth study for both softwood and hardwood. Furthermore, the type of analysis, whether experimental or modelling, needs to be standardized to have more comparable results

    Spiral drawing analysis with a smart ink pen to identify Parkinson's disease fine motor deficits

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    Introduction: Since the uptake of digitizers, quantitative spiral drawing assessment allowed gaining insight into motor impairments related to Parkinson's disease. However, the reduced naturalness of the gesture and the poor user-friendliness of the data acquisition hamper the adoption of such technologies in the clinical practice. To overcome such limitations, we present a novel smart ink pen for spiral drawing assessment, intending to better characterize Parkinson's disease motor symptoms. The device, used on paper as a normal pen, is enriched with motion and force sensors. Methods: Forty-five indicators were computed from spirals acquired from 29 Parkinsonian patients and 29 age-matched controls. We investigated between-group differences and correlations with clinical scores. We applied machine learning classification models to test the indicators ability to discriminate between groups, with a focus on model interpretability. Results: Compared to control, patients' drawings were characterized by reduced fluency and lower but more variable applied force, while tremor occurrence was reflected in kinematic spectral peaks selectively concentrated in the 4-7 Hz band. The indicators revealed aspects of the disease not captured by simple trace inspection, nor by the clinical scales, which, indeed, correlate moderately. The classification achieved 94.38% accuracy, with indicators related to fluency and power distribution emerging as the most important. Conclusion: Indicators were able to significantly identify Parkinson's disease motor symptoms. Our findings support the introduction of the smart ink pen as a time-efficient tool to juxtapose the clinical assessment with quantitative information, without changing the way the classical examination is performed

    Impact of nonstationarities on short heart rate variability recordings during obstructive sleep apnea

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    Obstructive sleep apnea (OSA) is a sleep disorder characterized by breathing pauses due to collapse of the upper airways. During OSA the autonomic modulation, as noninvasively assessed through heart period (HP) variability, is altered in a time-varying way even though time-varying properties of HP fluctuations are often disregarded by HP variability studies. We performed a time domain analysis computed over very short epochs corresponding to the sole OSA events explicitly accounting for HP variability nonstationarities. Length-matched epochs were extracted during OSA and quiet sleep (SLEEP) in 13 subjects suffering from OSA (11 males, age 55±11, apnea-hypopnea index 44±19). Mean HP, variance and variance of the residual after exponential detrending were assessed as well as the parameters a and b of the exponential fitting in the form y(n)=a·exp(b·n). HP mean and the parameter a increased during OSA compared to SLEEP. The variance of the residual was significantly lower than original variance during both OSA and SLEEP, while the dispersion of the parameter b was significantly larger. Nonstationarities were evident during both SLEEP and OSA but more dramatically apparent during OSA, thus stressing the need of accounting for them when the autonomic control during OSA is under scrutiny
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