241 research outputs found
Market orientation and the synergistic effect of mediating and moderating factors on performance : the case of the fashion cluster
It is commonly accepted that a market-oriented behaviour has a positive impact on organizational performance. This study provides additional support for the classical relationship between market orientation and organizational performance and goes further by not only including in the model the mediating role of both the organizational learning and organizational innovation, but also examining the potential moderating impact of the environmental conditions in the previous relationship.The analysis is based on data collected from a sample of 130 Portuguese SME operating in the fashion cluster. Implications and future research questions based on the findings are offered at the conclusion of the paper
Responses of woody species to spatial and temporal ground water changes in coastal sand dune systems
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 (&#936;<sub>pre</sub>) and bulk leaf &delta;<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 &#936;<sub>pre</sub> and bulk leaf &delta;<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
Deformation capacity evaluation for flat slab seismic design
The authors acknowledge the dedicated and careful work carried out by the Associate Editor and Reviewers whose constructive criticism contributed to a very significant improvement of the quality of the paper. Authors wish to dedicate this work to the memory of their co-author Prof. Ion Radu Pascu, UTCB Bucharest, who passed away on June 10, 2021.
Publisher Copyright:
© 2021, The Author(s).In flat-slab frames, which are typically designed as secondary seismic structures, the shear failure of the slab around the column (punching failure) is typically the governing failure mode which limits the deformation capacity and can potentially lead to a progressive collapse of the structure. Existing rules to predict the capacity of flat slab frames to resist imposed lateral displacements without losing the capability to bear gravity loads have been derived empirically from the results of cyclic tests on thin members. These rules account explicitly only for the ratio between acting gravity loads and resistance against concentric punching shear (so-called Gravity Shear Ratio). Recent rational models to estimate the deformation capacity of flat slabs show that other parameters can play a major role and predict a significant size effect (reduced deformation for thick slabs). In this paper, a closed-form expression to predict the deformation capacity of internal slab-column connections as a function of the main parameters is derived from the same model that has been used to develop the punching shear formulae for the second generation of Eurocode 2 for concrete structures. This expression is compared to an existing database of isolated internal slab-column connections showing fine accuracy and allowing to resolve the shortcomings of existing rules. In addition, the results of a testing programme on a full-scale flat-slab frame with two stories and 12 columns are described. The differences between measured interstorey drifts and local slab rotations influencing their capacity to resist shear forces are presented and discussed. With respect to the observed deformation capacities, similar values are obtained as in the isolated specimens and the predictions are confirmed for the internal columns, but significant differences are observed between internal, edge and corner slab-column connections. The effects of punching shear reinforcement and of integrity reinforcement (required according to Eurocode 2 to prevent progressive collapse after punching) are also discussed.publishersversionpublishe
Avaliação de genótipos de milheto para silagem no semiárido.
Objetivou-se com esta pesquisa avaliar o rendimento forrageiro, as características agronômicas e morfométricas das plantas e as perdas, perfil fermentativo e composição bromatológica de silagens de genótipos de milheto. Para avaliação das características agronômicas e morfométricas dos genótipos utilizou-se o delineamento experimental em blocos casualizados, com cinco repetições. Na fase de avaliação dos silos experimentais o delineamento passou a ser inteiramente casualizado, com quatro repetições. Foram testados os cultivares Sauna B, CMS 01, ADR 500, BRS 1501 e CMS 03. Não houve diferença para a PMV, PMS e MS. Os genótipos de milheto apresentaram uma média de PMV de 9.073 kg/ha no primeiro ciclo e de 10.054kg/ha na rebrota. Quanto à lâmina foliar e a produção de colmo não houve iferença em ambos os cortes. Os teores médios de AL variaram de 1,98 a 5,17%, para os genótipos SAUNA B e CMS 01, respectivamente. Para os teores de PB verificou-se efeito significativo entre os genótipos estudados, com valores variando de 11,56 a 7,90%. Os genótipos estudados se equivaleram tanto na avaliação das plantas como na avaliação das silagens, podendo ser utilizados como uma alternativa forrageira em regiões semiáridas
The NAD+-dependent deacetylase SIRT2 attenuates oxidative stress and mitochondrial dysfunction and improves insulin sensitivity in hepatocytes
Funding Information: European Regional Development Fund (ERDF), Centro 2020 Regional Operational Programme (CENTRO-01-0145-FEDER-000012: HealthyAging2020); COMPETE 2020 - Operational Programme for Competitiveness and Internationalisation and Portuguese national funds via FCT – Fundação para a Ciência e a Tecnologia (POCI-01-0145-FEDER-007440, SFRH/BPD/109347/ 2015 to R.M.O., SFRH/BD/86655/2012 to L.N. and SFRH/BPD/ 111815/2015 to P.G.); FLAD Life Science 2020 Grant to A.C.R.; European Molecular Biology Organization (EMBO Installation Grant to T.F.O.); DFG Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB) to T.F.O.Insulin resistance is a major predictor of the development of metabolic disorders. Sirtuins (SIRTs) have emerged as potential targets that can be manipulated to counteract age-related diseases, including type 2 diabetes. SIRT2 has been recently shown to exert important metabolic effects, but whether SIRT2 regulates insulin sensitivity in hepatocytes is currently unknown. The aim of this study is to investigate this possibility and to elucidate underlying molecular mechanisms. Here, we show that SIRT2 is downregulated in insulin-resistant hepatocytes and livers, and this was accompanied by increased generation of reactive oxygen species, activation of stress-sensitive ERK1/2 kinase, and mitochondrial dysfunction. Conversely, SIRT2 overexpression in insulin-resistant hepatocytes improved insulin sensitivity, mitigated reactive oxygen species production and ameliorated mitochondrial dysfunction. Further analysis revealed a reestablishment of mitochondrial morphology, with a higher number of elongated mitochondria rather than fragmented mitochondria instigated by insulin resistance. Mechanistically, SIRT2 was able to increase fusion-related protein Mfn2 and decrease mitochondrial-associated Drp1. SIRT2 also attenuated the downregulation of TFAM, a key mtDNA-associated protein, contributing to the increase in mitochondrial mass. Importantly, we found that SIRT2 expression in PBMCs of human subjects was negatively correlated with obesity and insulin resistance. These results suggest a novel function for hepatic SIRT2 in the regulation of insulin sensitivity and raise the possibility that SIRT2 activators may offer novel opportunities for preventing or treating insulin resistance and type 2 diabetes.publishersversionpublishe
The NAD+-dependent deacetylase SIRT2 attenuates oxidative stress and mitochondrial dysfunction and improves insulin sensitivity in hepatocytes
Insulin resistance is a major predictor of the development of metabolic disorders. Sirtuins (SIRTs) have emerged as potential targets that can be manipulated to counteract age-related diseases, including type 2 diabetes. SIRT2 has been recently shown to exert important metabolic effects, but whether SIRT2 regulates insulin sensitivity in hepatocytes is currently unknown. The aim of this study is to investigate this possibility and to elucidate underlying molecular mechanisms. Here, we show that SIRT2 is downregulated in insulin-resistant hepatocytes and livers, and this was accompanied by increased generation of reactive oxygen species, activation of stress-sensitive ERK1/2 kinase, and mitochondrial dysfunction. Conversely, SIRT2 overexpression in insulin-resistant hepatocytes improved insulin sensitivity, mitigated reactive oxygen species production and ameliorated mitochondrial dysfunction. Further analysis revealed a reestablishment of mitochondrial morphology, with a higher number of elongated mitochondria rather than fragmented mitochondria instigated by insulin resistance. Mechanistically, SIRT2 was able to increase fusion-related protein Mfn2 and decrease mitochondrial-associated Drp1. SIRT2 also attenuated the downregulation of TFAM, a key mtDNA-associated protein, contributing to the increase in mitochondrial mass. Importantly, we found that SIRT2 expression in PBMCs of human subjects was negatively correlated with obesity and insulin resistance. These results suggest a novel function for hepatic SIRT2 in the regulation of insulin sensitivity and raise the possibility that SIRT2 activators may offer novel opportunities for preventing or treating insulin resistance and type 2 diabetes.European Regional Development Fund (ERDF), Centro 2020 Regional Operational Programme (CENTRO-01-0145-FEDER-000012: HealthyAging2020); COMPETE 2020 - Operational Programme for Competitiveness and Internationalisation and Portuguese national funds via FCT – Fundação para a Ciência e a Tecnologia (POCI-01-0145-FEDER-007440, SFRH/BPD/109347/2015 to R.M.O., SFRH/BD/86655/2012 to L.N. and SFRH/BPD/111815/2015 to P.G.); FLAD Life Science 2020 Grant to A.C.R.; European Molecular Biology Organization (EMBO Installation Grant to T.F.O.); DFG Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB) to T.F.O
Simulation study of the inhomogeneous Olami-Feder-Christensen model of earthquakes
Statistical properties of the inhomogeneous version of the
Olami-Feder-Christensen (OFC) model of earthquakes is investigated by numerical
simulations. The spatial inhomogeneity is assumed to be dynamical. Critical
features found in the original homogeneous OFC model, e.g., the
Gutenberg-Richter law and the Omori law are often weakened or suppressed in the
presence of inhomogeneity, whereas the characteristic features found in the
original homogeneous OFC model, e.g., the near-periodic recurrence of large
events and the asperity-like phenomena persist.Comment: Shortened from the first version. To appear in European Physical
Journal
Cholesteryl Hemiazelate Present in Cardiovascular Disease Patients Causes Lysosome Dysfunction in Murine Fibroblasts
Funding Information: This work was financially supported by the FCT (Foundation for Science and Technology of the Portuguese Ministry of Science and Higher Education), Refs. 2022.01305.PTDC and 2022.03249.PTDC. The Coimbra Chemistry Centre (CQC) is supported by the FCT through projects UIDB/00313/2020 and UIDP/00313/2020. E.L. is the holder of a PhD fellowship from the FCT (2021.06265.BD). A.R.A.M. was funded by the FCT Stimulus of Scientific Employment Individual Support Call 2017 (CEECIND/01006/2017). R.P. was funded by the NHLBI Division of Intramural Research (ZIA HL006151-10). Publisher Copyright: © 2023 by the authors.There is growing evidence supporting the role of fibroblasts in all stages of atherosclerosis, from the initial phase to fibrous cap and plaque formation. In the arterial wall, as with macrophages and vascular smooth muscle cells, fibroblasts are exposed to a myriad of LDL lipids, including the lipid species formed during the oxidation of their polyunsaturated fatty acids of cholesteryl esters (PUFA-CEs). Recently, our group identified the final oxidation products of the PUFA-CEs, cholesteryl hemiesters (ChE), in tissues from cardiovascular disease patients. Cholesteryl hemiazelate (ChA), the most prevalent lipid of this family, is sufficient to impact lysosome function in macrophages and vascular smooth muscle cells, with consequences for their homeostasis. Here, we show that the lysosomal compartment of ChA-treated fibroblasts also becomes dysfunctional. Indeed, fibroblasts exposed to ChA exhibited a perinuclear accumulation of enlarged lysosomes full of neutral lipids. However, this outcome did not trigger de novo lysosome biogenesis, and only the lysosomal transcription factor E3 (TFE3) was slightly transcriptionally upregulated. As a consequence, autophagy was inhibited, probably via mTORC1 activation, culminating in fibroblasts’ apoptosis. Our findings suggest that the impairment of lysosome function and autophagy and the induction of apoptosis in fibroblasts may represent an additional mechanism by which ChA can contribute to the progression of atherosclerosis.publishersversionpublishe
Isokinetic muscle function comparison of lower limbs among elderly fallers and non-fallers
O objetivo deste estudo foi identificar se há diferenças entre o desempenho muscular de tornozelo, joelho e quadril em idosos com e sem relato de queda nos últimos seis meses. Foram incluídos 81 idosos com 65 anos ou mais: 56 negaram quedas (G1) e 25 relataram quedas (G2). Utilizou-se o questionário perfil de atividade humana para medir o nível de atividade física, e o dinamômetro isocinético para mensurar os parâmetros físicos da função muscular. Os grupos não diferiram entre si em relação à idade (p=0,925), duração (p=0,065) e frequência (p=0,302) da prática do exercício físico, índice de massa corpórea (p=0,995) e nível de atividade física (p=0,561). O G2 apresentou menor desempenho para as variáveis pico de torque de flexão e extensão de joelho esquerdo (p=0,027 e p=0,030, respectivamente) e trabalho por peso corporal (p=0,040) de flexão de joelho esquerdo a 60°/s; pico de torque e trabalho por peso corporal de flexão e extensão de joelho a 180°/s bilateralmente (p<0,050); e potência média de flexão de joelhos direito e esquerdo (p=0,030). A maioria das variáveis do tornozelo e quadril não apresentou diferenças entre os grupos. Apenas a variável pico de torque de extensão de quadril esquerdo foi significativamente maior no G1 (p=0,035). É importante considerar a função muscular do joelho na avaliação clínica de idosos para direcionar a intervenção terapêutica e a prevenção de quedas.The aim of this study was to identify whether there are differences between the performance of muscular groups of ankle, knee and hip among elderly people who didn't have falls and individuals who reported falls in the last six months. The study included 81 elderly aged 65 or older: 56 non-faller subjects (G1) and 25 faaller subjects (G2). To obtain the level of physical activity, the questionnaire Human Activity Profile was used, and the muscle function of the lower limbs was assessed using isokinetic dynamometer. The groups did not differ regarding age (p=0.925), duration (p=0.065) and frequency (p=0.302) of the practice of physical exercise, body mass index (BMI) (p=0.995) and level of physical activity (p=0.561). The G2 showed a lower performance of peak torque of left knee flexion and extension (p=0.027 and p=0.030, respectively) and work proportional to body weight (p=0.040) of left knee flexion at 60°/s; peak torque and work proportional to body weight of bilaterally knee flexion and extension at 180°/s (p<0.05) and average power of right and left knee extension (p=0.03). Most variables of ankle and hip joints did not differ between groups. Only peak torque of left hip extension was significantly higher in the non-faller group (p=0.035). It is important to consider knee muscle function in the clinical evaluation of elderly in order to make the intervention more assertive and thus to prevent falls
Trends in prevalence, mortality, and morbidity associated with high systolic blood pressure in Brazil from 1990 to 2017 : estimates from the “Global Burden of Disease 2017” (GBD 2017) study
Background: Hypertension remains the leading risk factor for cardiovascular disease (CVD) worldwide, and its impact in Brazil should be assessed in order to better address the issue. We aimed to describe trends in prevalence and burden of disease attributable to high systolic blood pressure (HSBP) among Brazilians ≥ 25 years old according to sex and federal units (FU) using the Global Burden of Disease (GBD) 2017 estimates. Methods: We used the comparative risk assessment developed for the GBD study to estimate trends in attributable deaths and disability-adjusted life-years (DALY), by sex, and FU for HSBP from 1990 to 2017. This study included 14 HSBP-outcome pairs. HSBP was defined as ≥ 140 mmHg for prevalence estimates, and a theoretical minimum risk exposure level (TMREL) of 110–115 mmHg was considered for disease burden. We estimated the portion of deaths and DALYs attributed to HSBP. We also explored the drivers of trends in HSBP burden, as well as the correlation between disease burden and sociodemographic development index (SDI). Results: In Brazil, the prevalence of HSBP is 18.9% (95% uncertainty intervals [UI] 18.5–19.3%), with an annual 0.4% increase rate, while age-standardized death rates attributable to HSBP decreased from 189.2 (95%UI 168.5–209.2) deaths to 104.8 (95%UI 94.9–114.4) deaths per 100,000 from 1990 to 2017. In spite of that, the total number of deaths attributable to HSBP increased 53.4% and HSBP raised from 3rd to 1st position, as the leading risk factor for deaths during the period. Regarding total DALYs, HSBP raised from 4th in 1990 to 2nd cause in 2017. The main driver of change of HSBP burden is population aging. Across FUs, the reduction in the age-standardized death rates attributable to HSBP correlated with higher SDI. Conclusions: While HSBP prevalence shows an increasing trend, age-standardized death and DALY rates are decreasing in Brazil, probably as results of successful public policies for CVD secondary prevention and control, but suboptimal control of its determinants. Reduction was more significant in FUs with higher SDI, suggesting that the effect of health policies was heterogeneous. Moreover, HSBP has become the main risk factor for death in Brazil, mainly due to population aging
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