3,213 research outputs found

    Organisational and occupational risk factors associated with work related injuries among public hospital employees in Costa Rica

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    Aims: To explore the relation between occupational and organisational factors and work related injuries (WRI) among public hospital employees in Costa Rica.Methods: A cross-sectional survey was conducted among a stratified random sample of 1000 employees from 10 of the 29 public hospitals in Costa Rica. A previously validated, self-administered questionnaire which included occupational and organisational factors and sociodemographic variables was used. From the final eligible sample ( n = 859), a total of 842 ( response rate 98%) questionnaires were returned; 475 workers were analysed after excluding not-at-risk workers and incomplete questionnaires. WRI were computed for the past six months.Results: Workers exposed to chemicals (RR = 1.36) and physical hazards ( RR = 1.26) had higher WRI rate ratios than non-exposed workers. Employees reporting job tasks that interfered with safety practices ( RR = 1.46), and a lack of safety training ( RR = 1.41) had higher WRI rate ratios than their counterparts. Low levels of safety climate ( RR = 1.51) and safety practices ( RR = 1.27) were individually associated with an increased risk of WRI. Also, when evaluated jointly, low levels of both safety climate and safety practices showed the highest association with WRI ( RR = 1.92).Conclusions: When evaluated independently, most of the occupational exposures and organisational factors investigated were significantly correlated with an increased injury risk. As expected, some of these associations disappeared when evaluated jointly. Exposure to chemical and physical hazards, lack of safety training, and low levels of safety climate and safety practices remained significant risk factors for WRI. These results will be important to consider in developing future prevention interventions in this setting

    Calculation of the absolute hydration enthalpy and free energy of H+ and OH-

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    An ab initio density functional theory and a polarizable continuum model were used to calculate the hydration enthalpy and Gibbs free energy of proton and hydroxide. The proton hydration enthalpy data is found to be in agreement with the results from cluster-ion solvation data. It was found that the effect of adding explicit hydration molecules is more significant for the hydration free energies than for the enthalpies.Dirección General de Enseñanza Superior PB98-0326Junta de Andalucía FQ20

    Near infrared nadir retrieval of vertical column densities: methodology and application to SCIAMACHY

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    Nadir observations with the shortwave infrared channels of SCIAMACHY on-board the ENVISAT satellite can be used to derive information on atmospheric gases such as CO, CH<sub>4</sub>, N<sub>2</sub>O, CO<sub>2</sub>, and H<sub>2</sub>O. For the operational level 1b-2 processing of SCIAMACHY data, a new retrieval code BIRRA (Beer InfraRed Retrieval Algorithm) has been developed. BIRRA performs a nonlinear or separable least squares fit (with bound constraints optional) of the measured radiance, where molecular concentration vertical profiles are scaled to fit the observed data. Here we present the forward modeling (radiative transfer) and inversion (least squares optimization) fundamentals of the code along with the further processing steps required to generate higher level products such as global distributions and time series. Moreover, various aspects of level 1 (observed spectra) and auxiliary input data relevant for successful retrievals are discussed. BIRRA is currently used for operational analysis of carbon monoxide vertical column densities from SCIAMACHY channel 8 observations, and is being prepared for methane retrievals using channel 6 spectra. A set of representative CO retrievals and first CH<sub>4</sub> results are presented to demonstrate BIRRA's capabilities

    Relation among Caregivers’ Burden, Abuse and Behavioural Disorder in People with Dementia

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    Dementia produces a loss of independence to carry out the activities of daily life. The great demand for care that these people need usually falls on the family through informal care. This study aims to analyse the burden showed by the informal caregiver of a person with dementia. In addition, we analyse whether this burden present in informal caregivers could be related to abusive behaviour. We also study the relationship between the stage of the disease, the appearance of behavioural disorders and the level of burden in the caregiver using the Scales of Zarit, CASE and FAST. The data showed that 45.50 per cent of caregivers have light burden or burden. After the research, it was identified that the presence of behavioural disorders in patients with dementia showed a correlation with the increase in both the main caregiver burden and abuse. An increase in the level of burden is followed by an increase in the level of abuse (r = 0.844; p = 0.000). Furthermore, we analysed several conditions that could have a correlation with this burden and abuse. It was found that burden in the caregiver could be linked with the presence of behavioural disorders, like aggression (r = 0.577; p = 0.008) and irritability (r = 0.600; p = 0.005) at the moderate stage of the disease. On the other hand, there is a positive correlation between the probability that people with dementia suffer abuse in the moderate stage of the disease and the presence of aggression (r = 0.732; p = 0.000), lack of inhibition (r = 0.571; p = 0.009) and irritability (r = 0.827; p = 0.000). Taking this data into account, burden and abuse seem to be linked to the presence of behavioural disorders in patients with dementia in the moderate stage

    A heuristic approach to the decision-making process of energy prosumers in a circular economy

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    Renewable distributed energy and self-consumption are promising and sustainable solutions in the energy-transition scenario for moving toward a circular economy. In this future scheme, prosumers are expected to play a leading role in the forthcoming sustainable energy market, facing new technical, economic, and financial challenges as energy producers at a small scale. In fact, the adoption of photovoltaic (PV) self-consumption systems requires mobilizing capital for investment and their interaction with the market. In this scenario, the aim of this paper was to explore insights into the decision-making process of prosumers to enhance the understanding of self-consumption deployment and to support effective policymaking. This study contributes to the state of the art by defining and classifying determinants of the energy prosumers’ decision-making process and their relevance using a heuristic approach. Potential measuring tools and methods are analyzed through a specific case study of Spanish prosumers

    Gold catalyzed multicomponent reactions beyond A3 coupling

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    The preparation of complex architectures has inspired the search for new methods and new processes in organic synthesis. Multicomponent reactions have become an interesting approach to achieve such molecular diversity and complexity. This review intends to illustrate important gold-catalyzed examples for the past ten years leading to interesting skeletons involved in biologically active compounds

    CMOS Receiver Front-End Architecture for High-Speed SI-POF Links

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    This works presents a new CMOS analog front-end for short-reach high-speed optical communications which compensates the limited bandwidth of POF channels and is suitable for the required large area photodetectorf The proposed pseudo-differential architecture, formed by a preamplifier and an equalizer, has been designed in a standard 0.18-μm CMOS process with a 1-V supply voltage targeting gigabit transmission for NRZ modulation. The preamplifier is based on the flipped voltage follower stage to attain a very low input resistance in order to handle the large phodiode capacitance (3 pF). The equalizer can adjust the high-frequency boosting and the gain, to compensate for the variation of the characteristics of the channel due to length of the fiber, connections, etc. causing subtantial changes of the fiber bandwidth. Reliable electrical models are employed for a Mitsubishi GH SI-POF with 10-m to 50-m length and for a S5972 silicon photodiode from Hamamatsu suitable for such a fiber due to its large diameter (0.8 mm) and responsivity at 650 nm (0.44A/W). The bandwidth of the received signal can be enhanced from 100 MHz to 1.4 GHz and from 300 MHz to 1.4 GHz for a 50-m and 10-m POF respectively. The proposed circuit shows a transimpedance of 41.5 dBΩ while the theoretical sensitivity from noise performance is below -7.5 dBm with a BER = 10-12. The power consumption is below 16 mW from 1-V supply voltage. In conclusion it targets 1.25 Gbps through a 1-mm SI-POF up to 50-m length with a commercial Si PIN photodiode

    A case study of zeolitization process: 'Tufo Rosso a Scorie Nere' (Vico Volcano, Italy). Inferences for a general model

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    This paper focuses on the authigenic mineralization processes acting on 'Tufo Rosso a Scorie Nere' (TRS), i.e. one of the main pyroclastic units of the Vico stratovolcano (Latium, Italy). The pyroclastic deposits appear in general massive and made of 'black vitreous vesiculated juvenile scoriae', immersed in an ashy matrix lithified after zeolitization processes. The main minerals are chabazite and phillipsite, and the zeolitic content is locally variable, reaching 68 % wt. Zeolites grow replacing both amorphous fraction and pre-existing phases, occurring inside both matrix and scoriae. Concerning scoriae, zeolitization moves from the rim to the core of the scoriaceous fragment as a function of (a) temperature of the fluids and (b) permeability (primary or secondary). Composition of parental fresh glass and that of zeolitized rocks is compatible with trachyte chemistry, lightly undersaturated in SiO2, and the alteration processes modified the parental rock chemical features. Zeolites genesis is ascribed to a 'geoautoclave-like system', and zeolites display a Si/Al ratio similar to that of the parental glasses. TRS presents promising mineralogical characteristics as supplementary cementitious material in the production of mixed cements

    Thermodynamic properties of CO2 + SO2 + CH4 mixtures over wide ranges of temperature and pressure. Evaluation of CO2/SO2 co-capture in presence of CH4 for CCS

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    In this work, density, vapor-liquid equilibrium and speed of sound measurements of the mixtures [CO2+ 4.72 mol% SO2+ 1.85 mol% CH4] and [CO2+ 0.09 mol% SO2+ 1.54 mol% CH4] were performed over the temperature range 263-373 K and at pressures of up to 30 MPa for density and up to 190 MPa for speed of sound. For the speed of sound measurements, the mixtures were doped with congruent to 0.8 mol% CH3OH. We compared our results to the values calculated using an extended version of the equation of state for combustion gases (EOSCG) that includes binary models for the CO2+ SO2 and CO2+ CH4 subsystems, and a perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state, validating both equations in this way. From our experimental results, we evaluated the impact of the simultaneous presence of SO2 and CH4 as impurities in anthropogenic CO2 on selected parameters for carbon capture and storage technology. With the understanding that chemical effects have not been considered, we concluded that the presence of 4.72 mol% SO2 compensates for the negative effect of 1.85 mol% CH4 on most of the studied parameters, resulting in a favorable fluid for carbon, capture and storage, contrary to the mixture with 0.09 mol% SO2 and 1.54 mol% CH4

    Application of a flipped classroom for model-based learning in electronics

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    This paper investigates the effectiveness of the flipped classroom methodology to build conceptual knowledge mentalmodels. In particular, it examines the learning process and outcomes of 40 students of a course on Physical Electronics inthe last year of a bachelor’s degree program in Physics, for which specific educational resources have been developed toimplement the flipped classroom. Among them, non-interactive resources are better to present topics and ideas, whereasinteractive resources are more useful to establish links between them to build and check the models. The examined dataentail grades, laboratory reports and rubrics, outcomes of learning activities, and direct observation, showing that theflipped classroom improves the construction of mental models, providing teaching resources where the topics and mainideas are presented, developed and exercised, and allowing students to establish links to build and check the models.Furthermore, this strategy increases the personal commitment of the students, fostering autonomy and cooperation withpeers, all of which makes it an effective pedagogical tool to build knowledge mental models
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