165 research outputs found

    Far fronte all’aggressività dei clienti in servizi in cambiamento: i Management Standards proteggono il benessere degli operatori?

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    Questo contributo analizza le relazioni tra aggressivit\ue0 dei clienti, risorse lavorative e benessere degli operatori in servizi pubblici che affrontano riconfigurazioni della loro missione. Basandosi sul modello Job Demands-Resources, lo studio ha esplorato: a) se il grado di esposizione percepita all'aggressivit\ue0 verbale influisse su esaurimento emotivo e soddisfazione al lavoro; b) se risorse del contesto lavorativo (controllo, chiarezza di ruolo, supporto dei colleghi, supporto dei superiori, modalit\ue0 di gestione del cambiamento) attenuassero gli esiti negativi; c) se tali risorse sostenessero maggiormente la soddisfazione lavorativa in condizioni di alta aggressivit\ue0. I dati, raccolti attraverso un questionario inviato a 279 lavoratori di biblioteche pubbliche italiane (154 rispondenti), sono stati analizzati mediante una serie di regressioni gerarchiche moderate. I risultati confermano che all\u2019aumentare dell\u2019aggressivit\ue0 dei clienti, percepita dagli operatori, cresce l\u2019esaurimento emotivo e decresce la soddisfazione lavorativa. Solo due risorse tra quelle considerate (modalit\ue0 di gestione del cambiamento organizzativo e supporto dei colleghi) hanno mostrato effetti protettivi sull\u2019esaurimento emotivo, mentre il legame tra risorse lavorative e soddisfazione lavorativa non \ue8 risultato modificarsi al variare dell\u2019intensit\ue0 di esposizione all\u2019aggressivit\ue0.This paper analyses the relations among perceived customers aggression, job resources and employees wellbeing in public services that are dealing with a changes in their mission towards customers. Based on the Job Demands \u2013 Resources model, the research explored a) if the level of exposure to verbal aggression by customers is related to employees\u2019 emotional exhaustion and job satisfaction; b) if a set of resources (control, clarity in role, support from colleagues and supervisors, change) contributes to buffering the negative impact of verbal aggression on burnout; c) if such resources are most beneficial in boosting job satisfaction under conditions of high aggressiveness. Data, gathered through a self-report questionnaire administered to 279 librarians in Italian public libraries (154 respondents), were analysed with a set of moderated hierarchical regression analyses. The results showed that increasing levels of perceived customer aggression are related to higher emotional exhaustion and lower job satisfactions. Only two of the organizational resources taken into consideration (change and support from colleagues) showed protective effects on emotional exhaustion, while the boosting effect was not confirmed

    Rapid South Atlantic spreading changes and coeval vertical motion in surrounding continents: Evidence for temporal changes of pressure-driven upper mantle flow

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    International audienceThe South Atlantic region displays (1) a topographic gradient across the basin, with Africa elevated relative to South America, (2) a bimodal spreading history with fast spreading rates in Late Cretaceous and Eo-Oligocene, and (3) episodic regional uplift events in the adjacent continents concentrated in Late Cretaceous and Oligocene. Here we show that these observations can be linked by dynamic processes within Earth's mantle, through temporal changes in asthenosphere flow beneath the region. The topographic gradient implies westward, pressure-driven mantle flow beneath the basin, while the rapid spreading rate changes, on order 10 million years, require significant decoupling of regional plate motion from the large-scale mantle buoyancy distribution through a mechanically weak asthenosphere. Andean topographic growth in late Miocene can explain the most recent South Atlantic spreading velocity reduction, arising from increased plate boundary forcing associated with the newly elevated topography. But this mechanism is unlikely to explain the Late Cretaceous/Tertiary spreading variations, as changes in Andean paleoelevation at the time are small. We propose an unsteady pressure-driven flow component in the asthenosphere beneath the South Atlantic region to explain the Late Cretaceous/Tertiary spreading rate variations. Temporal changes in mantle flow due to temporal changes in regional mantle pressure gradients imply a correlation of horizontal and vertical motions: we find that this prediction from our models agrees with geologic and geophysical observations of the South Atlantic region, including episodes of passive margin uplift, regional basin reactivation, and magmatic activity

    Fe-Ni-bearing serpentines from the saprolite horizon of Caribbean Ni-laterite deposits: new insights from thermodynamic calculations

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    Fe-Ni-bearing serpentine from the saprolite horizon is the main Ni ores in hydrous silicate-type Ni laterites and formed by chemical weathering of partially serpentinized ultramafic rocks under tropical conditions. During lateritization, Mg, Si, and Ni are leached from the surface and transported downwards. Fe2+ is oxidized to Fe3+ and fixed as insoluble Feoxyhydroxides (mostly goethite) that incorporate Ni. This Ni is later leached from goethite and incorporated in secondary serpentine and garnierite. As a result, a serpentine-dominated saprolite horizon forms over the ultramafic protolith, overlapped by a Fe-oxyhydroxide-dominated limonite horizon. The serpentine from the protolith (serpentine I) is of hydrothermal origin and yields similar Ni (0.10-0.62 wt.% NiO) and lower Fe (mostly 1.37-5.81 wt.% FeO) concentrations than the primary olivine. In contrast, Fe-Ni-bearing serpentine from the saprolite (serpentine II) shows significantly higher and variable Fe and Ni contents, typically ranging from 2.23 to 15.59 wt.% Fe2O3 and from 1.30 to 7.67 wt.% NiO, suggesting that serpentine get enriched in Fe and Ni under supergene conditions. This study presents detailed mineralogical, textural, and chemical data on this serpentine II, as well as new insights by thermodynamic calculations assuming ideal solution between Fe-, Ni- and Mg-pure serpentines. The aim is to assess if at atmospheric pressure and temperature Fe-Ni-bearing serpentine can be formed by precipitation. Results indicate that the formation of serpentine II under atmospheric pressure and temperature is thermodynamically supported, and pH, Eh, and the equilibrium constant of the reaction are the parameters that affect the results more significantly

    Diversidad de invertebrados bentónicos del Río de la Plata

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    The Rio de la Plata river present along the south coastal fringe different invertebrate assemblages related with substrate type, size sediment grains and organic matter content into the bedsediments. Other important factors influencing the distribution of benthos community in this river are the salinity and suspended solids of the water and the proximity to the riverside which increases the diversity of the habitats. The purpose of this study is to describe the taxonomic composition and ecological characteristics of the meso and macrobenthos associated with the river bed from Delta del Paraná to Magdalena, in Buenos Aires province. The listed taxa are the result of the revised literature and original data obtained from periodical samplings since 1993 till 1998. The principal components of the zoobenthos in the studied area were the allochthonous molluscs Corbicula fluminea on sandy and muddy bottoms and Limnoperna fortunei on hard substrates of the riverside. The nematods and oligochaetes dominated sediments with high allochthonous organic matter content imported from urban effluents. Palaemonetes argentinus, Macrobrachium borelli, Claudicuma platensis, Sinelobus stanfordi, Basphaeroma rhonbofrontale and Trichodactylus panoplus were the more common crustaceans in non polluted areas

    Development of a Synthetic Earth Gravity Model by 3D mass optimisation based on forward modelling

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    Several previous Synthetic Earth Gravity Model (SEGM) simulations are based on existing information about the Earth’s internal mass distribution. However, currently available information is insufficient to model the Earth’s anomalous gravity field on a global scale. The low-frequency information is missing when modelling only topography, bathymetry and crust (including the Mohorovičić discontinuity), but the inclusion of information on the mantle and core does not seem to significantly improve this situation. This paper presents a method to determine a more realistic SEGM by considering simulated 3D mass distributions within the upper mantle as a proxy for all unmodelled masses within the Earth.The aim is to improve an initial SEGM based on forward gravity modelling of the topography, bathymetry and crust such that the missing low-frequency information is now included. The simulated 3D mass distribution has been derived through an interactive and iterative mass model optimisation algorithm, which minimises geoid height differences with respect to a degree-360 spherical harmonic expansion of the EGM2008 global external gravity field model. We present the developed optimisation algorithm by applying it to the development of a global SEGM that gives a reasonably close fit to EGM2008, and certainly closer than a SEGM based only on the topography, bathymetry and crust

    Humanized Rag1−/−γc−/− Mice Support Multilineage Hematopoiesis and Are Susceptible to HIV-1 Infection via Systemic and Vaginal Routes

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    Several new immunodeficient mouse models for human cell engraftment have recently been introduced that include the Rag2−/−γc−/−, NOD/SCID, NOD/SCIDγc−/− and NOD/SCIDβ2m−/− strains. Transplantation of these mice with CD34+ human hematopoietic stem cells leads to prolonged engraftment, multilineage hematopoiesis and the capacity to generate human immune responses against a variety of antigens. However, the various mouse strains used and different methods of engrafting human cells are beginning to illustrate strain specific variations in engraftment levels, duration and longevity of mouse life span. In these proof-of-concept studies we evaluated the Balb/c-Rag1−/−γ−/− strain for engraftment by human fetal liver derived CD34+ hematopoietic cells using the same protocol found to be effective for Balb/c-Rag2−/−γc−/− mice. We demonstrate that these mice can be efficiently engrafted and show multilineage human hematopoiesis with human cells populating different lymphoid organs. Generation of human cells continues beyond a year and production of human immunoglobulins is noted. Infection with HIV-1 leads to chronic viremia with a resultant CD4 T cell loss. To mimic the predominant sexual viral transmission, we challenged humanized Rag1−/−γc−/− mice with HIV-1 via vaginal route which also resulted in chronic viremia and helper T cell loss. Thus these mice can be further exploited for studying human pathogens that infect the human hematopoietic system in an in vivo setting

    The utility of the new generation of humanized mice to study HIV-1 infection: transmission, prevention, pathogenesis, and treatment

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    Substantial improvements have been made in recent years in the ability to engraft human cells and tissues into immunodeficient mice. The use of human hematopoietic stem cells (HSCs) leads to multi-lineage human hematopoiesis accompanied by production of a variety of human immune cell types. Population of murine primary and secondary lymphoid organs with human cells occurs, and long-term engraftment has been achieved. Engrafted cells are capable of producing human innate and adaptive immune responses, making these models the most physiologically relevant humanized animal models to date. New models have been successfully infected by a variety of strains of Human Immunodeficiency Virus Type 1 (HIV-1), accompanied by virus replication in lymphoid and non-lymphoid organs, including the gut-associated lymphoid tissue, the male and female reproductive tracts, and the brain. Multiple forms of virus-induced pathogenesis are present, and human T cell and antibody responses to HIV-1 are detected. These humanized mice are susceptible to a high rate of rectal and vaginal transmission of HIV-1 across an intact epithelium, indicating the potential to study vaccines and microbicides. Antiviral drugs, siRNAs, and hematopoietic stem cell gene therapy strategies have all been shown to be effective at reducing viral load and preventing or reversing helper T cell loss in humanized mice, indicating that they will serve as an important preclinical model to study new therapeutic modalities. HIV-1 has also been shown to evolve in response to selective pressures in humanized mice, thus showing that the model will be useful to study and/or predict viral evolution in response to drug or immune pressures. The purpose of this review is to summarize the findings reported to date on all new humanized mouse models (those transplanted with human HSCs) in regards to HIV-1 sexual transmission, pathogenesis, anti-HIV-1 immune responses, viral evolution, pre- and post-exposure prophylaxis, and gene therapeutic strategies

    Adherence to antibiotic treatment guidelines and outcomes in the hospitalized elderly with different types of pneumonia

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    Background: Few studies evaluated the clinical outcomes of Community Acquired Pneumonia (CAP), Hospital-Acquired Pneumonia (HAP) and Health Care-Associated Pneumonia (HCAP) in relation to the adherence of antibiotic treatment to the guidelines of the Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) in hospitalized elderly people (65 years or older). Methods: Data were obtained from REPOSI, a prospective registry held in 87 Italian internal medicine and geriatric wards. Patients with a diagnosis of pneumonia (ICD-9 480-487) or prescribed with an antibiotic for pneumonia as indication were selected. The empirical antibiotic regimen was defined to be adherent to guidelines if concordant with the treatment regimens recommended by IDSA/ATS for CAP, HAP, and HCAP. Outcomes were assessed by logistic regression models. Results: A diagnosis of pneumonia was made in 317 patients. Only 38.8% of them received an empirical antibiotic regimen that was adherent to guidelines. However, no significant association was found between adherence to guidelines and outcomes. Having HAP, older age, and higher CIRS severity index were the main factors associated with in-hospital mortality. Conclusions: The adherence to antibiotic treatment guidelines was poor, particularly for HAP and HCAP, suggesting the need for more adherence to the optimal management of antibiotics in the elderly with pneumonia
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