209 research outputs found

    The Absolute Relativity Theory

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    This paper is a first presentation of a new approach of physics that we propose to refer as the Absolute Relativity Theory (ART) since it refutes the idea of a pre-existing space-time. It includes an algebraic definition of particles, interactions and Lagrangians. It proposed also a purely algebraic explanation of the passing of time phenomenon that leads to see usual Euler-Lagrange equations as the continuous version of the Knizhnik-Zamolodchikov monodromy. The identification of this monodromy with the local ones of the Lorentzian manifolds gives the Einstein equation algebraically explained in a quantized context. A fact that could lead to the unification of physics. By giving an algebraic classification of particles and interactions, the ART also proposes a new branch of physics, namely the Mass Quantification Theory, that provides a general method to calculate the characteristics of particles and interactions. Some examples are provided. The MQT also predicts the existence of as of today not yet observed particles that could be part of the dark matter. By giving a new interpretation of the weak interaction, it also suggests an interpretation of the so-called dark energy

    Specific fibre composition and metabolism of the rectus abdominis muscle of bovine Charolais cattle

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    Background: An important variability of contractile and metabolic properties between muscles has been highlighted. In the literature, the majority of studies on beef sensorial quality concerns M. longissimus thoracis. M. rectus abdominis (RA) is easy to sample without huge carcass depreciation and may appear as an alternative to M. longissimus thoracis for fast and routine physicochemical analysis. It was considered interesting to assess the muscle fibres of M. rectus abdominis in comparison with M. longissimus thoracis (LT) and M. triceps brachii (TB) on the basis of metabolic and contractile properties, area and myosin heavy chain isoforms (MyHC) proportions. Immunohistochemical, histochemical, histological and enzymological techniques were used. This research concerned two populations of Charolais cattle: RA was compared to TB in a population of 19 steers while RA was compared to LT in a population of 153 heifers. Results: RA muscle had higher mean fibre areas (3350 μm2 vs 2142 to 2639 μm2) than the two other muscles. In RA muscle, the slow-oxidative fibres were the largest (3957 μm2) and the fast-glycolytic the smallest (2868 μm2). The reverse was observed in TB muscle (1725 and 2436 μm2 respectively). In RA muscle, the distinction between fast-oxidative-glycolytic and fast-glycolytic fibres appeared difficult or impossible to establish, unlike in the other muscles. Consequently the classification based on ATPase and SDH activities seemed inappropriate, since the FOG fibres presented rather low SDH activity in this muscle in comparison to the other muscles of the carcass. RA muscle had a higher proportion of I fibres than TB and LT muscles, balanced by a lower proportion either of IIX fibres (in comparison to TB muscle) or of IIA fibres (in comparison to LT muscle). However, both oxidative and glycolytic enzyme activities were lower in RA than in TB muscle, although the LDH/ICDH ratio was higher in RA muscle (522 vs 340). Oxidative enzyme activities were higher in RA than in LT muscle, whereas glycolytic enzyme activity was lower. In RA muscle, contractile and metabolic properties appeared to be less well-correlated than in the two other muscles. Conclusions: RA muscle has some particularities in comparison to the LT and TB muscles, especially concerning the unusual large cross-section surface of SO fibres and the very low oxidative activity of intermediate IIA fibres

    The effect of dopamine therapy on ventral and dorsal striatum-mediated cognition in Parkinson\u27s disease: support from functional MRI.

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    The central aim of our study was to elucidate functions mediated by the ventral and dorsal striatum, respectively, to better understand the cognitive effects of dopamine replacement in Parkinson\u27s disease. We proposed that the ventral striatum underlies general learning of stimulus associations, whereas the dorsal striatum promotes integration of various influences on selecting. In Parkinson\u27s disease, dopamine depletion is substantially less notable in the ventral relative to the dorsal striatum, and therefore greater improvements are expected for dorsal striatum-mediated functions with dopamine replacement. Using a simple selection task, we found that dopamine replacement impaired encoding and facilitation of consistent stimulus-stimulus relations across trials. This finding was in line with our contention that ventral striatum mediates learning stimulus associations, even when explicit feedback or reward is not provided. In contrast, dopamine replacement enhanced interference related to assimilating conflicting influences on selection across trials, consistent with our hypothesis that the dorsal striatum supports deciding in ambiguous contexts. We further confirmed these separable roles for the ventral and dorsal striatum in our selection task with healthy young volunteers using functional magnetic resonance imaging. In summary, we present a within-subject, double dissociation of the effects of dopamine replacement in patients with Parkinson\u27s disease for ventral striatum-mediated facilitation and dorsal striatum-mediated interference, confirmed in a separate functional magnetic resonance imaging experiment. Defining the distinct functions of the ventral and dorsal striatum will have direct clinical implications. Titration of therapy in Parkinson\u27s disease is generally geared towards optimizing dorsal striatum-mediated motor symptoms, possibly at the expense of ventral striatum operations, a consequence that is only beginning to be recognized. Enhanced awareness of these different processes will translate into medication strategies that take into account those symptoms that dopamine replacement might hinder, as well as improve. Here, we show impairments in learning new stimulus associations compared with improvements in integrating varied influences related to selection. Ultimately, this knowledge will lead clinicians to survey a broader range of symptoms in determining optimal therapy based on individual patient priorities

    Examining dorsal striatum in cognitive effort using Parkinson\u27s disease and fMRI.

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    OBJECTIVE: Understanding cognition mediated by the striatum can clarify cognitive deficits in Parkinson\u27s disease (PD). Previously, we claimed that dorsal striatum (DS) mediates cognitive flexibility. To refute the possibility that variation in cognitive effort confounded our observations, we reexamined our data to dissociate cognitive flexibility from effort. PD provides a model for exploring DS-mediated functions. In PD, dopamine-producing cells supplying DS are significantly degenerated. DS-mediated functions are impaired off and improved on dopamine replacement medication. Functional magnetic resonance imaging (fMRI) can confirm striatum-mediated functions. METHODS: Twenty-two PD patients, off-on dopaminergic medication, and 22 healthy age-matched controls performed a number selection task. Numerical distance between number pairs varied systematically. Selecting between two numbers that are closer versus distant in magnitude is more effortful: the symbolic distance effect. However, selecting between closer versus distant number pairs is equivalent in the need to alter attention or response strategies (i.e., cognitive flexibility). In Experiment 2, 28 healthy participants performed the same task with simultaneous measurement of brain activity with fMRI. RESULTS: The symbolic distance effect was equivalent for PD versus control participants and across medication sessions. Furthermore, symbolic distance did not correlate with DS activation using fMRI. In this dataset, we showed previously that integrating conflicting influences on decision making is (1) impaired in PD and improved by dopaminergic therapy and (2) associated with preferential DS activation using fMRI. INTERPRETATION: These findings support the notion that DS mediates cognitive flexibility specifically, not merely cognitive effort, accounting for some cognitive deficits in PD and informing treatment

    Perception of cultured “meat” by Italian, Portuguese and Spanish consumers

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    The aim of this study was to investigate how consumers (n = 2,171) originated from South-Western Europe (Italy, Portugal, and Spain) perceive cultured “meat” (CM) and if their demographic characteristics (origin, gender, age, education, occupation, and meat consumption) are related to their willingness to try (WTT), to regularly eat (WTE) and to pay (WTP) for CM. We found the current respondents had an initially positive attitude towards CM: 49% of them perceived CM as “promising and/or acceptable” and 23% “fun and/or intriguing” whereas 29% considered it as “absurd and/or disgusting”. In addition, 66 and 25% would be willing and not willing to try CM, respectively. However, 43% had no WTE for CM and, 94% would not pay more for CM compared to conventional meat. Age and especially occupation were good indicators of consumer acceptance of CM. Respondents of 18–30 years of age had the highest acceptance. Respondents outside the meat sector had the highest WTE and people working within the meat sector had the lowest WTE, scientists (within or outside the meat sector) had the highest WTT, people not scientists but within the meat sector had the lowest WTT. Additionally, we found that men are more likely to accept CM than women, Spanish-speaking consumers had the highest WTT and WTE, people with vegan and vegetarian diets may pay more for CM but generally no more than for conventional meat. The perceptions that CM may be more eco-friendly, ethical, safe and healthy than conventional meat, and to a lower extent, the perception that current meat production causes ethical and environmental problems are likely to be major motives for the current respondents to try, regularly eat and pay for CM. On the opposite, lower perceptions of CM benefits and of conventional meat weaknesses more generally, plus emotional resistance towards CM are main barriers to accept CM

    Current situation and future prospects for beef production in Europe — A review

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    Publication history: Accepted - 26 April 2018; Published online - 24 May 2018.The European Union (EU) is the world’s third largest producer of beef. This contributes to the economy, rural development, social life, culture and gastronomy of Europe. The diversity of breeds, animal types (cows, bulls, steers, heifers) and farming systems (intensive, extensive on permanent or temporary pastures, mixed, breeders, feeders, etc) is a strength, and a weakness as the industry is often fragmented and poorly connected. There are also societal concerns regarding animal welfare and environmental issues, despite some positive environmental impacts of farming systems. The EU is amongst the most efficient for beef production as demonstrated by a relative low production of greenhouse gases. Due to regional differences in terms of climate, pasture availability, livestock practices and farms characteristics, productivity and incomes of beef producers vary widely across regions, being among the lowest of the agricultural systems. The beef industry is facing unprecedented challenges related to animal welfare, environmental impact, origin, authenticity, nutritional benefits and eating quality of beef. These may affect the whole industry, especially its farmers. It is therefore essential to bring the beef industry together to spread best practice and better exploit research to maintain and develop an economically viable and sustainable beef industry. Meeting consumers’ expectations may be achieved by a better prediction of beef palatability using a modelling approach, such as in Australia. There is a need for accurate information and dissemination on the benefits and issues of beef for human health and for environmental impact. A better objective description of goods and services derived from livestock farming is also required. Putting into practice “agroecology” and organic farming principles are other potential avenues for the future. Different future scenarios can be written depending on the major driving forces, notably meat consumption, climate change, environmental policies and future organization of the supply chain

    SR120819A, an orally-active and selective neuropeptide Y Y1 receptor antagonist

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    AbstractAn orally-active antagonist of neuropeptide Y (NPY) Y1 receptors, SR 120819A, has been characterized. This compound displays highly selective and competitive affinity for rat, guinea-pig and human (Ki = 15 nM) NPY Y1 receptors. In vitro, SR 120819A blocks the inhibitory effect of NPY on adenylyl cyclase activity in human SK-N-MC cells and that of the selective Y1 agonist, [Leu31,Pro34]NPY, on rabbit vas deferens contraction (pA2 = 7.20 ± 0.07). In vivo, by intravenous route, this compound acts as an antagonist in anesthetized guinea-pigs and, notably, after oral administration, SR 120819A counteracts the pressor response of [Leu31,Pro34]NPY (5 μg/kg i.v.) with a long duration of action (>4 h at 5 mg/kg p.o.). Thus, SR 120819A is the first orally-effective NPY Y1 receptor antagonist yet descrobed. It could be a useful tool for exploring the role of NPY and the therapeutic relevance of an antagonist at NPY Y1 receptors

    Various Statistical Approaches to Assess and Predict Carcass and Meat Quality Traits

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    Publication history: Accepted - 8 April 2020; Published - 22 April 2020.The beef industry is organized around di erent stakeholders, each with their own expectations, sometimes antagonistic. This article first outlines these di ering perspectives. Then, various optimization models that might integrate all these expectations are described. The final goal is to define practices that could increase value for animal production, carcasses and meat whilst simultaneously meeting the main expectations of the beef industry. Di erent models previously developed worldwide are proposed here. Two new computational methodologies that allow the simultaneous selection of the best regression models and the most interesting covariates to predict carcass and/or meat quality are developed. Then, a method of variable clustering is explained that is accurate in evaluating the interrelationships between di erent parameters of interest. Finally, some principles for the management of quality trade-o s are presented and the Meat Standards Australia model is discussed. The “Pareto front” is an interesting approach to deal jointly with the di erent sets of expectations and to propose a method that could optimize all expectations togethe

    Correlação clínico e radiológica dos nódulos de Heberden e Bouchard na osteoartrite de mãos/ Clinical radiological correlation of Heberden and Bouchard’s nodes in hand osteoarthritis

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    Objetivo: Verificar a associação entre achados clínicos ao exame articular de mãos e os achados radiológicos no raio-x correspondente, em pacientes com osteoartrite de mãos.Métodos: Avaliados 13 pacientes em acompanhamento ambulatorial com diagnóstico de osteoartrite de mãos segundo critérios do Colégio Americano de Reumatologia (ACR). Dados clínico-demográficos como: sexo, idade e duração da doença foram obtidos. Exame clínico das mãos para a detecção dos nódulos de Heberden e Bouchard e anotado sua localização na mão foi realizada por examinador independente da avaliação radiológica. O estudo radiológico constou de raio-x simples de mãos de frente e bilateral. A presença ou não de redução de espaço articular (REA), erosões (E), esclerose óssea subcondral (ESC) e osteófitos (OST ) foram avaliados por examinador independente. Na análise estatística utilizou-se o teste do Qui-Quadrado corrigido pelo método de Yates.Resultados: Nos 13 pacientes estudados avaliamos 234 articulações, sendo encontrados nódulos em 184 (78%) pacientes e em 50 (22%) não. Nas 184 articulações, em 81 (34%) havia concordância do exame clínico com o exame radiológico e em 9  (3,8%) não. 23% dos pacientes eram do sexo masculino e 77% do sexo feminino, média de idade dos pacientes de 63 anos. A duração de doença em média de 6,76 anos. REA) associada ã ESC) foi encontrada em 42 de 81 articulações com nódulos e alteração no exame radiológico, respondendo por 51% das articulações com correlação clínico-radiológica. REA associada a ESC associada a Osteófito (OST) em 15 (16,6%). REA isolada em 14,4%. REA associada a ESC associada a Erosão (E) em 5,5%. REA associada a ESC associada a E associada a OST em 5 (5,5%). REA associada a E associada a OST em 3 (3,3%). ESC isolada em 2 (2,2%). REA associada a E em 2 (2,2%). ESC associada a OST em 1 (1,1%). OST isolada em 1 (1,1%) das articulações com nódulos e alteração no exame radiológico. A análise dos resultados mostrou que existe associação clínico-radiológica na OA em relação aos nódulos de Heberden e Bouchard (p = 0,001).Conclusão: A alterações radiológicas mais prevalente foram a redução do espaço articular associada à esclerose subcondral, representando 51,8% das alterações radiológicas associadas aos nódulos de Heberden e Bouchard. Nossos resultados demonstram haver uma correlação entre o achado clínico de nódulos de Heberden e Bouchard e alterações radiológicas em pacientes com osteoartrite de mãos
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