557 research outputs found

    Palaeoenvironmental changes based on foraminifera during the late Holocene at the Beagle Channel, Argentina

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    A foraminiferal faunal study was carried out in a Holocene marine section from Arroyo Baliza, located on the northwest coast of the Beagle Channel, to contribute to the knowledge of the palaeoenvironmental conditions during the marine Holocene event. Foraminiferal assemblage was represented by 32 species distributed among 21 genera. The assemblage was dominated by Elphidium macellum (Fichtel & Moll) Elphidium alvarezianum (d’Orbigny), Cribroelphidium excavatum (Terquem) and Buccella peruviana (d’Orbigny), accompanied by Cibicides fletcheri Galloway & Wissler and Cibicidoides dispars (d’Orbigny) in low proportion. The predominance of Peridiniales dinocysts in the marine palynomorphs assemblage, suggested inner neritic conditions with cooler and more nutrient-rich waters. The distribution of the foraminiferal species was variable throughout the section indicating palaeoenvironmental changes in Arroyo Baliza between 3499–2595 cal yr BP. A gradual passage from high energy, cold and well-oxygenated marine waters towards a shallower environment with low energy and low to moderate salinity of the waters were linked to the regressive phase. This study complements and supports the previous palynological data from this section, which reflects an increase in number and diversity of dinocyst species indicating marine environmental conditions during the late Holocene as it exists today in the Beagle Channel.Fil: Bernasconi, Emiliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Candel, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Borromei, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; Argentin

    Integrating Topological Proofs with Model Checking to Instrument Iterative Design

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    System development is not a linear, one-shot process. It proceeds through refinements and revisions. To support assurance that the system satisfies its requirements, it is desirable that continuous verification can be performed after each refinement or revision step. To achieve practical adoption, formal verification must accommodate continuous verification efficiently and effectively. Model checking provides developers with information useful to improve their models only when a property is not satisfied, i.e., when a counterexample is returned. However, it is desirable to have some useful information also when a property is instead satisfied. To address this problem we propose TOrPEDO, an approach that supports verification in two complementary forms: model checking and proofs. While model checking is typically used to pinpoint model behaviors that violate requirements, proofs can instead explain why requirements are satisfied. In our work, we introduce a specific notion of proof, called Topological Proof. A topological proof produces a slice of the original model that justifies the property satisfaction. Because models can be incomplete, TOrPEDO supports reasoning on requirements satisfaction, violation, and possible satisfaction (in the case where satisfaction depends on unknown parts of the model). Evaluation is performed by checking how topological proofs support software development on 12 modeling scenarios and 15 different properties obtained from 3 examples from literature. Results show that: (i) topological proofs are ≈60% smaller than the original models; (ii) after a revision, in ≈78% of cases, the property can be re-verified by relying on a simple syntactic check

    Non-parametric estimation of survival probabilities with a time-dependent exposure switch: application to (simulated) heart transplant data

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    Background: To summarize the survival experience of patients waiting for heart transplant and to compare it with the post-transplant survival it is not possible to use the Kaplan-Meier estimator considering the intervention status as fixed in time because of the well known "immortaltime bias" issue.Methods: We reviewed and applied to a simulated dataset the available methods to perform a non-parametric analysis accounting for the time-varying nature of the transplant status. Specifically we considered the Simon-Makuch estimator and the recently proposed "clock-back" estimator.Results: We showed that the Simon-Makuch estimator for the survival of patients on list is unbiased but the corresponding estimator of the post-transplant survival is not reliable for non-markov contexts like the one considered. Instead, if the semi-Markov assumption could be postulated (the post-transplant mortality depends mainly on the time since transplant and not on the waiting time to the intervention), the "clock-back" estimator produces valid results.Conclusion: We enlightened the importance of testing the process memory assumptions (e.g. Markov properties) in order to choose the approach more reliable. Moreover, we recommend the use of the Simon-Makuch method to study the survival of patients before the interventionand the use of the "clock back" estimator for the post-intervention survival in semi-markovian contexts

    What's the name? Weight stigma and the battle against obesity

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    Childhood obesity has spread worldwide, it is on the rise, starts earlier and is more severe, despite all treatment attempts.According to recent studies, weight stigma is a factor that can hinder the success of therapies. Healthcare workers, mainly paediatricians, need to feel the urgency of anti-stigma training. The use of non-stigmatizing terminologies and images in various areas (school, sports clubs, healthcare, media, society in general) can improve disease management

    Justicia penal de menores. Análsis de la situacion actual y los futuros cambios que se pretenden instaurar en la responsabilidad penal de menores.

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    96 p.Este trabajo tiene por objeto el análisis del actual sistema de responsabilidad de menores. Esto implica analizar la legislación aplicable a los menores infractores de la ley penal, y establecer cuáles son las deficiencias y problemas que presenta en relación a las normas de Convención Internacional de Derechos del Niño. También se analizarán los cambios que se han intentado realizar por el gobierno, especialmente a través del proyecto de ley que establece un sistema de responsabilidad de los adolescentes infractores de la ley penal, que actualmente se encuentra en el Parlamento. La investigación también pretende anticipar la situación en la que quedarán los menores en caso de aprobarse esta nueva iniciativa legal. En consecuencia, este trabajo pretende sintetizar al actual sistema jurídico de menores, tanto en lo referente a derechos, garantías y procedimientos, del sistema actual y del que se pretende implementar

    Chemical contaminants in breast milk: a brief critical overview

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    Breast milk is the reference food for the infant both for its content in nutrients, necessary for normal growth and development, and for the presence of biologically active substances that provide protection from infections and a lower susceptibility to several non-communicable diseases typical of adulthood. However, substances that the mother assimilates from the environment, and which can be potentially harmful, can be concentrated in breast milk. In fact, for a long time, breast milk has been considered a reliable biomarker of the environment. The huge increase in the production and use of chemicals that has occurred in recent decades with consequent wide dispersion in the soil, water and air makes it necessary to carefully evaluate the levels of contamination. Based on a synthetic review of current knowledge, it can be confirmed that breast milk is always the first choice. However, various aspects remain to be clarified based on more robust scientific data. This review aims to stimulate further research, managed by multi-disciplinary teams which, with the use of the most modern chemical analysis tools, determine the presence of exogenous chemicals in longitudinal studies during pregnancy and lactation, clarifying their metabolic fate and evaluating them in the 'scope of global exposure (exposome). To this end, the gaps present in the studies conducted so far are also highlighted to make future scientific approaches increasingly robust

    Endocrine Disrupting Chemicals' Effects in Children: What We Know and What We Need to Learn?

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    Thousands of natural or manufactured chemicals were defined as endocrine-disrupting chemicals (EDCs) because they can interfere with hormone activity and the endocrine system. We summarize and discuss what we know and what we still need to learn about EDCs' pathogenic mechanisms of action, as well as the effects of the most common EDCs on endocrine system health in childhood. The MEDLINE database (PubMed) was searched on 13 May 2022, filtering for EDCs, endocrine diseases, and children. EDCs are a group of compounds with high heterogeneity, but usually disrupt the endocrine system by mimicking or interfering with natural hormones or interfering with the body's hormonal balance through other mechanisms. Individual EDCs were studied in detail, while humans' "cocktail effect" is still unclear. In utero, early postnatal life, and/or pubertal development are highly susceptible periods to exposure. Human epidemiological studies suggest that EDCs affect prenatal growth, thyroid function, glucose metabolism, obesity, puberty, and fertility through several mechanisms. Further studies are needed to clarify which EDCs can mainly act on epigenetic processes. A better understanding of EDCs' effects on human health is crucial to developing future regulatory strategies to prevent exposure and ensure the health of children today, in future generations, and in the environment

    Effects of Cord Serum Insulin, IGF-II, IGFBP-2, IL-6 and Cortisol Concentrations on Human Birth Weight and Length: Pilot Study

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    The IGF system is recognised to be important for fetal growth. We previously described increased Insulin-like growth factor binding protein (IGFBP)-2 cord serum concentrations in intra-uterine growth retardation (IUGR) compared with appropriate for gestational age (AGA) newborns, and a positive relationship of IGFBP-2 with Interleukin (IL)-6. The role of cortisol in the fetus at birth is largely unknown, and interactions among peptides are their real effect on birth size is unknown. Furthermore, almost all studies have previously assayed peptides in serum several years after birth, and follow-up data from pregnancy are always lacking. This study aimed at establishing and clarifying the effect of cord serum insulin, IGF-II, IGFBP-2, cortisol and IL-6 concentrations on birth length and weight.23 IUGR and 37 AGA subjects were followed up from the beginning of pregnancy, and were of comparable gestational age. Insulin, IGF-II, IGFBP-2, cortisol and IL-6 concentrations were assayed in cord serum at birth, and a multiple regression model was designed and applied to assess which were the significant biochemical determinants of birth size.Insulin, cortisol, and IL-6, showed similar concentrations in IUGR and AGA as previously described, whereas IGF-II was lower, and IGFBP-2 increased in IUGR compared with AGA. IGF-II serum concentration was found to have a significant positive effect on both birth length (r:(:)0.546; p: 0.001) and weight (r:0.679; p: 0.0001). IGFBP-2 had a near significant negative effect on both birth weight (r:-0.342; p: 0.05) and length (r:-0.372; p:0.03).IGF-II cord serum concentration was shown to have a significant positive effect on both birth length and weight, whereas IGFBP-2 had a significant negative effect. Insulin, cortisol, and IL-6 cord serum concentrations had no significant effect on birth size
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