447 research outputs found

    Synthetic calcium carbonate improves the effectiveness of treatments with nanolime to contrast decay in highly porous limestone

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    Three synthetized polymorphs of calcium carbonate have been tested in combination with the suspension of nanolime particles as potential consolidating agents for contrasting stone decay and overcome some of the limitations of nanolime agents when applied to substrates with large porosity. The modifications induced in the pore network of the Maastricht limestone were analyzed with microscopy and in a non-invasive fashion with small angle neutron scattering and synchrotron radiation micro-computed tomography. A reduction in porosity and pore accessibility at the micrometric scale was detected with the latter technique, and ascribed to the improved pore-filling capacity of the consolidation agent containing CaCO3 particles. These were found to be effectively bound to the carbonated nanolime, strengthening the pore-matrix microstructure. Penetration depth and positive effect on porosity were found to depend on the particle size and shape. Absence of significant changes in the fractal nature of the pore surface at the nanoscale, was interpreted as indication of the negligible contribution of nanolime-based materials in the consolidation of stones with large porosity. However, the results indicate that in such cases, their effectiveness may be enhanced when used in combination with CaCO3 particles, owing to the synergic effect of chemical/structural compatibility and particle size distribution

    Reflexiones de estudiantes universitarios, docentes de Agroecología (U.N.Cuyo) y agentes de extensión del INTA en prácticas de intervención socioproductivas en las zonas de Luján de Cuyo y Valle de Uco, Mendoza

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    En el marco de la asignatura Agroecología y Ambientes Rurales de la carrera en Ingeniería en Recursos Naturales Renovables (FCA- UNCuyo), se han realizado durante 10 años académicos consecutivos, dos actividades consistentes en visitar a diferentes tipos sociales agrarios ubicados en Luján de Cuyo y el Valle de Uco. En las nombradas actividades, los estudiantes realizan una visita extendida a productores que integran diferentes cadenas productivas, con el objetivo de caracterizar el ecosistema, sociosistema y tecnosistema en cada caso, además de diferenciar manejos convencionales y agroecológicos. Con la información recabada y reflexionada, los estudiantes realizan un trabajo integrador, con carácter de condición obligatoria para rendir el examen final de la asignatura, que rescata una problemática detectada y propone una solución socio tecnológica con base agroecológica, ajustada a las características de tipo social agrario abordado. El nombrado material queda a disposición de los actores involucrados para ser utilizado como una herramienta de comprensión de la dinámica socio-productiva y territorial. En el presente relato realizamos una breve síntesis sobre las experiencias de cada visita a campo y se presentan las reflexiones de los actores involucrados acerca de esta experiencia.In the framework of agroecology and rural environments race course in Engineering in Renewable Natural Resources (FCA UNCuyo) were performed for 10 consecutive school years, two consistent activities visit different agricultural social types are located in Lujan de Cuyo and Uco Valley. In the named activities, students made an extended visit to producers that integrate different production chains, in order to characterize the ecosystem, sociosistema and Technosystem in each case, in addition to conventional agro differentiate and handling. With the information gathered and reflected, students take an integrative work, as an obligatory condition to take the final exam of the subject, who rescues a detected problem and proposes a solution partner agroecologically technological basis and adjusted to the characteristics of a social nature agricultural addressed. The named material is available to the actors involved to be used as a tool for understanding the socio-productive and territorial dynamics. In this story is a brief summary of experiences of each field visit and reflections of stakeholders about this experience are presented.Eje: A2: Paisajes, Territorios y AgroecologíaFacultad de Ciencias Agrarias y Forestale

    Reflexiones de estudiantes universitarios, docentes de Agroecología (U.N.Cuyo) y agentes de extensión del INTA en prácticas de intervención socioproductivas en las zonas de Luján de Cuyo y Valle de Uco, Mendoza

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    En el marco de la asignatura Agroecología y Ambientes Rurales de la carrera en Ingeniería en Recursos Naturales Renovables (FCA- UNCuyo), se han realizado durante 10 años académicos consecutivos, dos actividades consistentes en visitar a diferentes tipos sociales agrarios ubicados en Luján de Cuyo y el Valle de Uco. En las nombradas actividades, los estudiantes realizan una visita extendida a productores que integran diferentes cadenas productivas, con el objetivo de caracterizar el ecosistema, sociosistema y tecnosistema en cada caso, además de diferenciar manejos convencionales y agroecológicos. Con la información recabada y reflexionada, los estudiantes realizan un trabajo integrador, con carácter de condición obligatoria para rendir el examen final de la asignatura, que rescata una problemática detectada y propone una solución socio tecnológica con base agroecológica, ajustada a las características de tipo social agrario abordado. El nombrado material queda a disposición de los actores involucrados para ser utilizado como una herramienta de comprensión de la dinámica socio-productiva y territorial. En el presente relato realizamos una breve síntesis sobre las experiencias de cada visita a campo y se presentan las reflexiones de los actores involucrados acerca de esta experiencia.In the framework of agroecology and rural environments race course in Engineering in Renewable Natural Resources (FCA UNCuyo) were performed for 10 consecutive school years, two consistent activities visit different agricultural social types are located in Lujan de Cuyo and Uco Valley. In the named activities, students made an extended visit to producers that integrate different production chains, in order to characterize the ecosystem, sociosistema and Technosystem in each case, in addition to conventional agro differentiate and handling. With the information gathered and reflected, students take an integrative work, as an obligatory condition to take the final exam of the subject, who rescues a detected problem and proposes a solution partner agroecologically technological basis and adjusted to the characteristics of a social nature agricultural addressed. The named material is available to the actors involved to be used as a tool for understanding the socio-productive and territorial dynamics. In this story is a brief summary of experiences of each field visit and reflections of stakeholders about this experience are presented.Eje: A2: Paisajes, Territorios y AgroecologíaFacultad de Ciencias Agrarias y Forestale

    Reflexiones de estudiantes universitarios, docentes de Agroecología (U.N.Cuyo) y agentes de extensión del INTA en prácticas de intervención socioproductivas en las zonas de Luján de Cuyo y Valle de Uco, Mendoza

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    En el marco de la asignatura Agroecología y Ambientes Rurales de la carrera en Ingeniería en Recursos Naturales Renovables (FCA- UNCuyo), se han realizado durante 10 años académicos consecutivos, dos actividades consistentes en visitar a diferentes tipos sociales agrarios ubicados en Luján de Cuyo y el Valle de Uco. En las nombradas actividades, los estudiantes realizan una visita extendida a productores que integran diferentes cadenas productivas, con el objetivo de caracterizar el ecosistema, sociosistema y tecnosistema en cada caso, además de diferenciar manejos convencionales y agroecológicos. Con la información recabada y reflexionada, los estudiantes realizan un trabajo integrador, con carácter de condición obligatoria para rendir el examen final de la asignatura, que rescata una problemática detectada y propone una solución socio tecnológica con base agroecológica, ajustada a las características de tipo social agrario abordado. El nombrado material queda a disposición de los actores involucrados para ser utilizado como una herramienta de comprensión de la dinámica socio-productiva y territorial. En el presente relato realizamos una breve síntesis sobre las experiencias de cada visita a campo y se presentan las reflexiones de los actores involucrados acerca de esta experiencia.In the framework of agroecology and rural environments race course in Engineering in Renewable Natural Resources (FCA UNCuyo) were performed for 10 consecutive school years, two consistent activities visit different agricultural social types are located in Lujan de Cuyo and Uco Valley. In the named activities, students made an extended visit to producers that integrate different production chains, in order to characterize the ecosystem, sociosistema and Technosystem in each case, in addition to conventional agro differentiate and handling. With the information gathered and reflected, students take an integrative work, as an obligatory condition to take the final exam of the subject, who rescues a detected problem and proposes a solution partner agroecologically technological basis and adjusted to the characteristics of a social nature agricultural addressed. The named material is available to the actors involved to be used as a tool for understanding the socio-productive and territorial dynamics. In this story is a brief summary of experiences of each field visit and reflections of stakeholders about this experience are presented.Eje: A2: Paisajes, Territorios y AgroecologíaFacultad de Ciencias Agrarias y Forestale

    Measurement of event shapes in deep inelastic scattering at HERA

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    Inclusive event-shape variables have been measured in the current region of the Breit frame for neutral current deep inelastic ep scattering using an integrated luminosity of 45.0 pb^-1 collected with the ZEUS detector at HERA. The variables studied included thrust, jet broadening and invariant jet mass. The kinematic range covered was 10 < Q^2 < 20,480 GeV^2 and 6.10^-4 < x < 0.6, where Q^2 is the virtuality of the exchanged boson and x is the Bjorken variable. The Q dependence of the shape variables has been used in conjunction with NLO perturbative calculations and the Dokshitzer-Webber non-perturbative corrections (`power corrections') to investigate the validity of this approach.Comment: 7+25 pages, 6 figure

    Angular and Current-Target Correlations in Deep Inelastic Scattering at HERA

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    Correlations between charged particles in deep inelastic ep scattering have been studied in the Breit frame with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb-1. Short-range correlations are analysed in terms of the angular separation between current-region particles within a cone centred around the virtual photon axis. Long-range correlations between the current and target regions have also been measured. The data support predictions for the scaling behaviour of the angular correlations at high Q2 and for anti-correlations between the current and target regions over a large range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations and Monte Carlo models correctly describe the trends of the data at high Q2, but show quantitative discrepancies. The data show differences between the correlations in deep inelastic scattering and e+e- annihilation.Comment: 26 pages including 10 figures (submitted to Eur. J. Phys. C

    Adjuvant trastuzumab in the treatment of her-2-positive early breast cancer: a meta-analysis of published randomized trials

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    <p>Abstract</p> <p>Background</p> <p>Breast cancer is the most common cancer in women in the U.S. and Western Europe. Amplification of the her-2/neu gene occurs in approximately 25% of invasive ductal carcinomas of the breast. The first HER-2/neu-targeted approach to reach the clinic was trastuzumab, a humanized monoclonal antibody directed against the extracellular domain of the HER-2/neu protein. Trastuzumab therapy prolongs the survival of patients with metastático HER-2/neu-overexpressing breast cancer when combined with chemotherapy and has recently been demonstrated to lead to dramatic improvements in disease-free survival when used in the adjuvant therapy setting in combination with or following chemotherapy. Here, we performed a meta-analysis of completed clinical trials of adjuvant trastuzumab in the adjuvant setting. Survival, recurrence, brain metastases, cardiotoxicity and directions for future research are discussed.</p> <p>Methods</p> <p>A meta-analysis of randomized controlled trials (RCT) was performed comparing adjuvant trastuzumab treatment for HER2-positive early breast cancer (EBC) to observation. The MEDLINE, EMBASE, CANCERLIT and Cochrane Library databases, and abstracts published in the annual proceedings were systematically searched for evidence. Relevant reports were reviewed by two reviewers independently and the references from these reports were searched for additional trials, using guidelines set by QUOROM statement criteria.</p> <p>Results</p> <p>Pooled results from that five randomized trials of adjuvant Trastuzumab showed a significant reduction of mortality (p < 0.00001), recurrence (p < 0.00001), metastases rates (p < 0.00001) and second tumors other than breast cancer (p = 0.007) as compared to no adjuvant Trastuzumab patients. There were more grade III or IV cardiac toxicity after trastuzumab (203/4555 = 4.5%) versus no trastuzumab (86/4562 = 1.8%). The likelihood of cardiac toxicity was 2.45-fold higher (95% CI 1.89 – 3.16) in trastuzumab arms, however that result was associated with heterogeneity. The likelihood of brain metastases was 1.82-fold higher (95% CI 1.16 – 2.85) in patients who received trastuzumab.</p> <p>Conclusion</p> <p>The results from this meta-analysis are sufficiently compelling to consider 1 year of adjuvant trastuzumab treatment for women with HER-2-positive EBC based on the risk: benefit ratio demonstrated in these studies. Adequate assessment of HER-2/neu status is critical, and careful cardiac monitoring is warranted because of cardiac toxicity. Clinical trials should be designed to answer unsolved questions.</p

    Trastuzumab in the Adjuvant Treatment of HER2-Positive Early Breast Cancer Patients: A Meta-Analysis of Published Randomized Controlled Trials

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    BACKGROUND: Adjuvant trastuzumab therapy has yielded conflicting results for overall survival, concerns about central nervous system (CNS) metastasis, and questions about optimal schedule. Therefore, we carried out a meta-analysis to assess the benefits of concurrent or sequential trastuzumab with adjuvant chemotherapy for early breast cancer patients with HER2-positive tumors. METHODS: Computerized and manual searches were performed to identify randomized clinical trials comparing adjuvant chemotherapy with or without trastuzumab in HER2-positive early breast cancer patients. Odds ratios were used to estimate the association between the addition of trastuzumab to adjuvant chemotherapy and various survival outcomes. The fixed-effects or random-effects model was used to combine data. FINDINGS: With six eligible studies identified, this analysis demonstrated that patients with HER2-positive breast cancer derived benefit in disease-free survival, overall survival, locoregional recurrence and distant recurrence (all P<0.001) from the addition of trastuzumab to adjuvant chemotherapy, whereas trastuzumab did worse in CNS recurrence as compared to the control group (P = 0.018). Furthermore, concomitant use of trastuzumab significantly lowered the hazard of death (P<0.001) but bore a higher incidence of CNS recurrence (P = 0.010), while statistical significance failed to be discerned for either overall survival (P = 0.069) or CNS metastasis (P = 0.374) between the sequential and observation arms. CONCLUSION: This analysis verifies the efficacy of trastuzumab in the adjuvant setting. Additionally, our findings indirectly corroborate the superiority of concurrent trastuzumab to sequential use and also illuminate that prolonged survival is the possible reason for the higher incidence of CNS with trastuzumab versus observation

    Differential Effects of Migration and Deportation on HIV Infection among Male and Female Injection Drug Users in Tijuana, Mexico

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    HIV prevalence is rising, especially among high risk females in Tijuana, Baja California, a Mexico-US border city situated on major migration and drug trafficking routes. We compared factors associated with HIV infection among male and female injection drug users (IDUs) in Tijuana in an effort to inform HIV prevention and treatment programs. IDUs aged ≥18 years were recruited using respondent-driven sampling and underwent testing for HIV, syphilis and structured interviews. Logistic regression identified correlates of HIV infection, stratified by gender. Among 1056 IDUs, most were Mexican-born but 67% were born outside Tijuana. Reasons for moving to Tijuana included deportation from the US (56% for males, 29% for females), and looking for work/better life (34% for females, 15% for males). HIV prevalence was higher in females versus males (10.2% vs. 3.5%, p = 0.001). Among females (N = 158), factors independently associated with higher HIV prevalence included younger age, lifetime syphilis infection and living in Tijuana for longer durations. Among males (N = 898), factors independently associated with higher HIV prevalence were syphilis titers consistent with active infection, being arrested for having ‘track-marks’, having larger numbers of recent injection partners and living in Tijuana for shorter durations. An interaction between gender and number of years lived in Tijuana regressed on HIV infection was significant (p = 0.03). Upon further analysis, deportation from the U.S. explained the association between shorter duration lived in Tijuana and HIV infection among males; odds of HIV infection were four-fold higher among male injectors deported from the US, compared to other males, adjusting for all other significant correlates (p = 0.002). Geographic mobility has a profound influence on Tijuana's evolving HIV epidemic, and its impact is significantly modified by gender. Future studies are needed to elucidate the context of mobility and HIV acquisition in this region, and whether US immigration policies adversely affect HIV risk
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