8,677 research outputs found

    Simplicial minisuperspace models in the presence of a massive scalar field with arbitrary scalar coupling

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    We extend previous simplicial minisuperspace models to account for arbitrary scalar coupling \eta R\phi^2.Comment: 24 pages and 9 figures. Accepted for publication by Classical and Quantum Gravit

    ANALYSIS OF THE PERFORMANCE OF ABOVE-KNEE AMPUTEES IN CLIMBING STAIRS

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    INTRODUCTION Although a large investment has been already made in the study of the walking performance of amputees a greater understanding of the capacities of these subjects is still needed. In this context we undertook the present study in order to analyse the performance of above-knee amputees (AKA) in tasks related to locomotion. We studied two groups of individuals, one of able bodied (AB) subjects and a AKA group, perform ing two different tasks, namely, level ground (LG) walking and climbing stairs (CS). METHODS For each individual and for each task three trials were recorded. The CS task corresponded to the. climbing of a staircase of three 16 cm in height steps. The performances were normalised by comparing a complete LG walking cycle and the climbing CS from the first to the second step. These performances were filmed by two video cameras, one located at the side and another at the back of the track. A thirteen segments body model is used to calculate the center of mass (CM). The percent values of the CM co-ordinates relative to the subject's height is calculated along the vertical (Z axis) , the horizontal antero-posterior (Y axis) and the (axis X) normal to the previous ones using a method developed by Enseberg et al. (1992). The sagittal and lateral inclinations of the trunk and the sagittal rotation of the knee are also computed. RESULTS AND DISCUSSIONS The CM for the AKA group performing the LG and CS tasks is located at a lower level (Z), further to the back (Y) and, generally, on the side of the prosthesis . (X) as compared with its location for the AB group performing the same tasks. These results agree with those obtained Engsberg et al. (1992) for the LG task. The CM location along the Z axis is determined fundamentally by the forward flexion of the trunk and, for both groups of subjects, is lower for the CS task than for the LG tasks as a result of the need to place this center on the vertical of the propulsive limb. For both tasks, the CM location along the Y axis is similar for the two groups and only slightly more posterior for the AKA group in result of the larger backwards rotation of the arm opposite to the prosthesis. The CM location along the X is, for the AKA group, always opposite to the prosthetic side as a result of the trunk compensating inclination in that direction. For the AB group, the CM oscillates naturally from side to side of the body sagittal plane. CONCLUSIONS We may conclude from these results that the two tasks correspond to significantly different performances and that the differences are more profound for the AKA group. The use of a staircase to test the performance of AKA subjects is clinically relevant as it brings up some of the most serious problems associated with the quality of adaptation of the prosthesis to the patient. REFERENCES Engsberg, J., K. Tedford & J. Harder (1992). Center of mass location and segment angular orientation of below-knee amputee and able-bodied children during walking. Arch. Phys. Med. Reahabili, 73, 1163-1168

    Mercapturate Pathway in the Tubulocentric Perspective of Diabetic Kidney Disease

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    BACKGROUND: The recent growing evidence that the proximal tubule underlies the early pathogenesis of diabetic kidney disease (DKD) is unveiling novel and promising perspectives. This pathophysiological concept links tubulointerstitial oxidative stress, inflammation, hypoxia, and fibrosis with the progression of DKD. In this new angle for DKD, the prevailing molecular mechanisms on proximal tubular cells emerge as an innovative opportunity for prevention and management of DKD as well as to improve diabetic dysmetabolism. SUMMARY: The mercapturate pathway (MAP) is a classical metabolic detoxification route for xenobiotics that is emerging as an integrative circuitry detrimental to resolve tubular inflammation caused by endogenous electrophilic species. Herein we review why and how it might underlie DKD. Key Messages: MAP is a hallmark of proximal tubular cell function, and cysteine-S-conjugates might represent targets for early intervention in DKD. Moreover, the biomonitoring of urinary mercapturates from metabolic inflammation products might be relevant for the implementation of preventive/management strategies in DKD.info:eu-repo/semantics/publishedVersio

    State transition and electrocaloric effect of BaZrx_{x}Ti1x_{1-x}O3_3: simulation and experiment

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    The electrocaloric effect (ECE) of BaZrx_{x}Ti1x_{1-x}O3_3 (BZT) is closely related to the relaxor state transition of the materials. This work presents a systematic study on the ECE and the state transition of the BZT, using a combined canonical and microcanonical Monte Carlo simulations based a lattice-based on a Ginzburg-Landau-type Hamiltonian. For comparison and verification, experimental measurements have been carried on BTO and BZT (x=0.12x=0.12 and 0.20.2) samples, including the ECE at various temperatures, domain patterns by Piezoresponse Force Microscopy at room temperature, and the P-E loops at various temperatures. Results show that the dependency of BZT behavior of the Zr-concentration can be classified into three different stages. In the composition range of 0x0.2 0 \leq x \leq 0.2 , ferroelectric domains are visible, but ECE peak drops with increasing Zr-concentration harshly. In the range of 0.3x0.7 0.3 \leq x \leq 0.7 , relaxor features become prominent, and the decrease of ECE with Zr-concentration is moderate. In the high concentration range of x0.8 x \geq 0.8 , the material is almost nonpolar, and there is no ECE peak visible. Results suggest that BZT with certain low range of Zr-concentration around x=0.120.3x=0.12 \sim 0.3 can be a good candidate with relatively high ECE and simutaneously wide temperature application range at rather low temperature

    Indução de gemas axilares de cajazeira (Spondias mombin L.) sob condições in vitro.

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    Este estudo tem por objetivo avaliar condicoes de desinfestacao que reduzam a incidencia de contaminantes e nao afetem as taxas de inducao de gemas e de formacao de brotos axilares em segmentos nodais de cajazeira.bitstream/CNPAT-2010/5392/1/Pa-061.pd

    Towards a Conceptualization of Sociomaterial Entanglement

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    In knowledge representation, socio-technical systems can be modeled as multiagent systems in which the local knowledge of each individual agent can be seen as a context. In this paper we propose formal ontologies as a means to describe the assumptions driving the construction of contexts as local theories and to enable interoperability among them. In particular, we present two alternative conceptualizations of the notion of sociomateriality (and entanglement), which is central in the recent debates on socio-technical systems in the social sciences, namely critical and agential realism. We thus start by providing a model of entanglement according to the critical realist view, representing it as a property of objects that are essentially dependent on different modules of an already given ontology. We refine then our treatment by proposing a taxonomy of sociomaterial entanglements that distinguishes between ontological and epistemological entanglement. In the final section, we discuss the second perspective, which is more challenging form the point of view of knowledge representation, and we show that the very distinction of information into modules can be at least in principle built out of the assumption of an entangled reality

    Children’s right to participate in early childhood care and education settings and relative innovatory supportive digital tools for ECCE professionals’ development

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    Young children’s participation is key to developing a culture of human rights, democracy, and rule of law and according to Council of Europe (2017) and United Nations (2005). In these terms, children’s right to participate is described as a key aspect in the framework of educational quality, and the positive relationship between children’s right to participate and early childhood care and education (ECCE) quality is already documented. Although this concept is not new to ECCE professionals, its application seems to remain a challenge within everyday activities. It is thus important for ECCE professionals to reflect on this right and on the practices towards its promotion, in order to be able to supply high quality education. The paper presents the innovatory attempts regarding the digital tools developed within the PARTICIPA Erasmus+ project (Professional development tools supporting participation rights in early childhood education) aiming to involve three target group -directors, teachers and teachers’ assistants- working in all types of early childhood care and education settings, so that have a digital space to reflect about children’s right to participate and its implementation. More specifically, the paper presents (a) a training program targeting the ECCE settings’ professionals provided through a massive open online course (MOOC) in 5 languages and disseminated in an online learning platform, focusing on the theoretical and practical aspects of children’s right to participate (i.e., state of the art, relevant pedagogical practices), (b) toolkits (i.e., validated self-assessment questionnaires) for ECCE directors and teachers and teacher assistants supported by discrete qualitative studies.info:eu-repo/semantics/publishedVersio

    Responses of woody species to spatial and temporal ground water changes in coastal sand dune systems

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    In spite of the relative importance of groundwater in costal dune systems, studies concerning the responses of vegetation to ground water (GW) availability variations, particularly in Mediterranean regions, are scarce. Thus, the main purpose of this study is to compare the responses of co-occurring species possessing different functional traits, to changes in GW levels (i.e. the lowering of GW levels) in a sand dune ecosystem. For that, five sites were established within a 1 km<sup>2</sup> area in a meso-mediterranean sand dune ecosystem dominated by a <i>Pinus pinaster</i> forest. Due to natural topographic variability and anthropogenic GW exploitation, substantial variability in depth to GW between sites was found. Under these conditions it was possible to identify the degree of usage and dependence on GW of different plant species (two deep-rooted trees, a drought adapted shrub, a phreatophyte and a non-native woody invader) and how GW dependence varied seasonally and between the heterogeneous sites. Results indicated that the plant species had differential responses to changes in GW depth according to specific functional traits (i.e. rooting depth, leaf morphology, and water use strategy). Species comparison revealed that variability in pre-dawn water potential (Ψ<sub>pre</sub>) and bulk leaf δ<sup>13</sup>C was related to site differences in GW use in the deep-rooted (<i>Pinus pinaster, Myrica faya</i>) and phreatophyte (<i>Salix repens</i>) species. However, such variation was more evident during spring than during summer drought. The exotic invader, <i>Acacia longifolia</i>, which does not possess a very deep root system, presented the largest seasonal variability in Ψ<sub>pre</sub> and bulk leaf δ<sup>13</sup>C. In contrast, the response of <i>Corema album</i>, an endemic understory drought-adapted shrub, seemed to be independent of water availability across seasons and sites. Thus, the susceptibility to lowering of GW due to anthropogenic exploitation, in plant species from sand dunes, is variable, being particularly relevant for deep rooted species and phreatophytes, which seem to depend heavily on access to GW

    Production of Cu/Diamond composites for first-wall heat sinks

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    Due to their suitable thermal conductivity and strength copper-based materials have been considered appropriate heat sinks for first wall panels in nuclear fusion devices. However, increased thermal conductivity and mechanical strength are demanded and the concept of property tailoring involved in the design of metal matrix composites advocates for the potential of nanodiamond dispersions in copper. Copper-nanodiamond composite materials can be produced by mechanical alloying followed by a consolidation operation. Yet, this powder metallurgy route poses several challenges: nanodiamond presents intrinsically difficult bonding with copper; contamination by milling media must be closely monitored; and full densification and microstructural homogeneity should be obtained with consolidation. The present line of work is aimed at an optimization of the processing conditions of Cu-nanodiamond composites. The challenges mentioned above have been addressed, respectively, by incorporating chromium in the matrix to form a stable carbide interlayer binding the two components; by assessing the contamination originating from the milling operation through particle-induced X-ray emission spectroscopy; and by comparing the densification obtained by spark plasma sintering with hot-extrusion data from previous studies
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