2,064 research outputs found

    Participatory Guarantee System and Social Capital for Sustainable Development in Brazil: The Case Study of OPAC Orgânicos Sul de Minas

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    In recent years there has been a growing international interest in alternative certification strategies for organic products. Specifically, participatory guarantee systems (PGS) have proved to be particularly suitable not only to simplify bureaucratic procedures for small organic producers and reduce the cost of certification, but also to generate empowerment, social inclusion and mutual support among farmers. The purpose of this paper is to study the elements of social capital (SC) found in a PGS through the use of social network indicators using the Organizaçao Participativa de Acreditaçao e Certificaçao "Orgânicos Sul de Minas" (OPAC-OSM) as a case study. The research was carried out in the southern part of Minas Gerais, one of the states of the Brazilian Federation, where organic production represents a viable alternative for small and medium-sized farmers. In particular, a survey was carried out to capture the opinions of managers (presidents or directors) about their participation in the OPAC-OSM, and about the level of interaction and degree of trust between members. Relational skills, which are the basis of structural SC, were analyzed both at the level of individual units and at the level of the general network of the OPAC-OSM. An in-degree centrality score assigned to OPAC-OSM members was obtained from each network. These scores have been correlated with variables of the database that were chosen due to their relevance in assessing the level of social capital. According to the results, the factors that most reinforced the proof of SC among the OPAC-OSM members were the level of information and the degree of trust and collaboration networks, with special emphasis on female participation. From the analysis carried out, it is possible to conclude that PGS are powerful tools in the strengthening of SC far beyond the aspect of quality assurance, which remains the main objective of the OPAC

    Fabrication of MEMS Directional Acoustic Sensors for Underwater Operation

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    The article of record as published may be found at https://doi.org/10.3390/s20051245In this work, microelectromechanical systems (MEMS)-based directional acoustic sensors operating in an underwater environment are explored. The studied sensors consist of a free-standing single wing or two wings pivoted to a substrate. The sensors operate in a narrow frequency band determined by the resonant frequency of the mechanical structure. The electronic readout of the mechanical response is obtained using interdigitated comb finger capacitors attached to the wings. The characteristics of MEMS sensors immersed in silicone oil are simulated using finite element modeling. The performance of the sensors is evaluated both in air and underwater. For underwater testing and operation, the sensors are packaged in a housing containing silicone oil, which was specially developed to present near unity acoustic transmission. The measurements show that the resonant frequency of the sensors obtained in air shifts to a lower frequency when immersed in silicone oil, which is primarily due to the mass loading of the liquid. The peak sensitivity of the MEMS sensors is approximately 6 mV/Pa or −165 dB re 1 V/μPa, and the directional response shows a dipole pattern. The signal-to-noise ratio was found to be about 200 or 23 dB at 1 Pa incident sound pressure. The results show the potential of MEMS sensors to be used in underwater applications for sound source localization

    Design of two retention basins along the torrent Liera on the Gares Valley (Dolomites, North East Italy) after the storm Vaia

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    A storm called “Vaia” affected the North East Italy and South West of Austria at the end of October 2018. On the Gares Valley (Canale d’Agordo, North East Italian Alps), the abundant runoff triggered several in-channel debris flows that transported hundreds of thousands of cubic meters of sediments on the valley bottom. Some control works for retaining the sediment volume have then been built in the most threatened sites. Herein we show the design of two retention basins that should protect both the Liera torrent and the main road parallel to it. We computed the debris-flow volume to be retained both using an empirical law and simulated solid-liquid hydrographs corresponding to a return period of 300 years. The estimate of the debris-flow volume in the empirical law depends on the basin area upstream of the deposition zone, whereas, in the solid-liquid hydrographs, it depends on the area of the basin closed at the initiation area, as well as on the design rainfall

    First Measurements of a Prototype of a New Generation Pixel Readout ASIC in 65 nm CMOS for Extreme Rate HEP Detectors at HL-LHC

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    A first prototype of a readout ASIC in CMOS 65nm for a pixel detector at High Luminosity LHC is described. The pixel cell area is 50x50 um2 and the matrix consists of 64x64 pixels. The chip was designed to guarantee high efficiency at extreme data rates for very low signals and with low power consumption. Two different analogue front-end designs, one synchronous and one asynchronous, were implemented, both occupying an area of 35x35 um2. ENC value is below 100e- for an input capacitance of 50 fF and in-time threshold below 1000e-. Leakage current compensation up to 50 nA with power consumption below 5 uW. A ToT technique is used to perform charge digitization with 5-bit precision using either a 40 MHz clock or a local Fast Oscillator up to 800 MHz. Internal 10-bit DAC's are used for biasing, while monitoring is provided by a 12-bit ADC. A novel digital architecture has been developed to ensure above 99.5% hit efficiency at pixel hit rates up to 3 GHz/cm2, trigger rates up to 1 MHz and trigger latency of 12.5 us. The total power consumption per pixel is below 5uW. Analogue dead-time is below 1%. Data are sent via a serializer connected to a CMOS-to-SLVS transmitter working at 320 MHz. All IP-blocks and front-ends used are silicon-proven and tested after exposure to ionizing radiation levels of 500-800 Mrad. The chip was designed as part of the Italian INFN CHIPIX65 project and in close synergy with the international CERN RD53 and was submitted in July 2016 for production. Early test results for both front-ends regarding minimum threshold, auto-zeroing and low-noise performance are high encouraging and will be presented in this paper

    Pressure and Flow Properties of Cannulae for Extracorporeal Membrane Oxygenation I: Return (Arterial) Cannulae

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    Adequate extracorporeal membrane oxygenation support in the adult requires cannulae permitting blood flows up to 6-8 L/minute. In accordance with Poiseuille's law, flow is proportional to the fourth power of cannula inner diameter and inversely proportional to its length. Poiseuille's law can be applied to obtain the pressure drop of an incompressible, Newtonian fluid (such as water) flowing in a cylindrical tube. However, as blood is a pseudoplastic non-Newtonian fluid, the validity of Poiseuille's law is questionable for prediction of cannula properties in clinical practice. Pressure-flow charts with non-Newtonian fluids, such as blood, are typically not provided by the manufacturers. A standardized laboratory test of return (arterial) cannulae for extracorporeal membrane oxygenation was performed. The aim was to determine pressure-flow data with human whole blood in addition to manufacturers' water tests to facilitate an appropriate choice of cannula for the desired flow range. In total, 14 cannulae from three manufacturers were tested. Data concerning design, characteristics, and performance were graphically presented for each tested cannula. Measured blood flows were in most cases 3-21% lower than those provided by manufacturers. This was most pronounced in the narrow cannulae (15-17 Fr) where the reduction ranged from 27% to 40% at low flows and 5-15% in the upper flow range. These differences were less apparent with increasing cannula diameter. There was a marked disparity between manufacturers. Based on the measured results, testing of cannulae including whole blood flows in a standardized bench test would be recommended.info:eu-repo/semantics/publishedVersio

    Connections between Classical and Parametric Network Entropies

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    This paper explores relationships between classical and parametric measures of graph (or network) complexity. Classical measures are based on vertex decompositions induced by equivalence relations. Parametric measures, on the other hand, are constructed by using information functions to assign probabilities to the vertices. The inequalities established in this paper relating classical and parametric measures lay a foundation for systematic classification of entropy-based measures of graph complexity

    Measuring subjective well-being from a multidimensional and temporal perspective: Italian adaptation of the I COPPE scale

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    Background: The objective of this study is to present the psychometric and cultural adaptation of the I COPPE scale to the Italian context. The original 21-item I COPPE was developed by Isaac Prilleltensky and colleagues to integrate a multidimensional and temporal perspective into the quantitative assessment of people’s subjective well-being. The scale comprises seven domains (Overall, Interpersonal, Community, Occupation, Psychological, Physical, and Economic well-being), which tap into past, present, and future self-appraisals of well-being. Methods: The Italian adapted version of the I COPPE scale underwent translation and backtranslation procedure. After a pilot study was conducted on a local sample of 683 university students, a national sample of 2432 Italian citizens responded to the final translated version of the I COPPE scale, 772 of whom re-completed the same survey after a period of four months. Respondents from both waves of the national sample were recruited partly through on-line social networks (i.e. Facebook, Twitter, and SurveyMonkey) and partly by university students who had been trained in Computer-Assisted Survey Information Collection. Results: Data were first screened for non-valid cases and tested for multivariate normality and missing data. The correlation matrix revealed highly significant correlation values, ranging from medium to high for nearly all congeneric variables of the I COPPE scale. Results from a series of nested and non-nested model comparisons supported the 7-factor correlated-traits model originally hypothesised, with factor loadings and inter-item reliability ranging from medium to high. In addition, they revealed that the I COPPE scale has strong internal reliability, with composite reliability always higher than .7, satisfactory construct validity, with average variance extracted nearly always higher than .5, and and full strict invariance across time. Conclusions: The Italian adaptation of the I COPPE scale presents appropriate psychometric properties in terms of both validity and reliability, and therefore can be applied to the Italian context. Some limitation and recommendations for future studies are discussed

    Neutrality and the Response of Rare Species to Environmental Variance

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    Neutral models and differential responses of species to environmental heterogeneity offer complementary explanations of species abundance distribution and dynamics. Under what circumstances one model prevails over the other is still a matter of debate. We show that the decay of similarity over time in rocky seashore assemblages of algae and invertebrates sampled over a period of 16 years was consistent with the predictions of a stochastic model of ecological drift at time scales larger than 2 years, but not at time scales between 3 and 24 months when similarity was quantified with an index that reflected changes in abundance of rare species. A field experiment was performed to examine whether assemblages responded neutrally or non-neutrally to changes in temporal variance of disturbance. The experimental results did not reject neutrality, but identified a positive effect of intermediate levels of environmental heterogeneity on the abundance of rare species. This effect translated into a marked decrease in the characteristic time scale of species turnover, highlighting the role of rare species in driving assemblage dynamics in fluctuating environments

    Regulation of Bestrophins by Ca2+: A Theoretical and Experimental Study

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    Bestrophins are a recently discovered family of Cl− channels, for which no structural information is available. Some family members are activated by increased intracellular Ca2+ concentration. Bestrophins feature a well conserved Asp-rich tract in their COOH terminus (Asp-rich domain), which is homologous to Ca2+-binding motifs in human thrombospondins and in human big-conductance Ca2+- and voltage-gated K+ channels (BKCa). Consequently, the Asp-rich domain is also a candidate for Ca2+ binding in bestrophins. Based on these considerations, we constructed homology models of human bestrophin-1 (Best1) Asp-rich domain using human thrombospondin-1 X-ray structure as a template. Molecular dynamics simulations were used to identify Asp and Glu residues binding Ca2+ and to predict the effects of their mutations to alanine. We then proceeded to test selected mutations in the Asp-rich domain of the highly homologous mouse bestrophin-2. The mutants expressed in HEK-293 cells were investigated by electrophysiological experiments using the whole-cell voltage-clamp technique. Based on our molecular modeling results, we predicted that Asp-rich domain has two defined binding sites and that D301A and D304A mutations may impact the binding of the metal ions. The experiments confirmed that these mutations do actually affect the function of the protein causing a large decrease in the Ca2+-activated Cl− current, fully consistent with our predictions. In addition, other studied mutations (E306A, D312A) did not decrease Ca2+-activated Cl− current in agreement with modeling results
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