869 research outputs found

    Diagnóstico del deterioro de la piedra en el patrimonio construido. Datos y perspectivas

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    Stone and other materials used for the construction of historic buildings, memorial statues, gravestones and similar are exposed to weathering and polluting agents and, therefore, progressive decay. Such deterioration, whether physical, chemical or biological, involves mineral phases and their interrelationships (structure and texture).A review of the analytical procedures applied in scientific research on stone damage has revealed the need for appropriate tools and tests (each with a specific scope, depending on the extant damage) to identify decay processes and apply the correct “therapy”, i.e. temporary and/or permanent protection (cleaning, protection, reinforcement, repair and/or replacement). A number of case histories of famous components of the Italian built heritage are discussed in the context of the use of integrated methodologies for researching decay in different kinds of stone.La piedra y otros materiales utilizados para construir edificios históricos, estatuas conmemorativas, lápidas, etc. sufren la acción de los agentes atmosféricos y contaminantes y, por tanto, a una degradación progresiva. En dicha degradación, ya sea física, química o biológica, intervienen las fases minerales de la piedra y sus correspondientes interrelaciones (estructura y textura).Un análisis de los procedimientos analíticos aplicados en la investigación científica sobre los daños en la piedra ha puesto de manifiesto la necesidad de herramientas y pruebas adecuadas (cada una con un objetivo concreto, según el daño existente) para identificar los procesos de degradación y aplicar la «terapia» adecuada; es decir, una protección provisional o definitiva (limpieza, protección, refuerzo, reparación o sustitución).Se comentan varios casos prácticos relacionados con conocidos elementos del patrimonio construido italiano en el contexto del empleo de metodologías integradas para la investigación de la degradación en distintos tipos de piedra

    Hydrochemical and Isotopic Features of the Khaung Daing Hot Spring (Inle lake, Southern Shan State, Myanmar)

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    Abstract The Inle lake watershed develops along a right-lateral strike-slip fault running parallel to the Sangaing fault, a major continental transform fault between the India and Sunda Plates. Located on the northwestern border of the Inle lake basin, the Khaung Daing hot spring outflows at a temperature of about 70C. This contribution represents a reconnaissance study of the spring and describes its main hydrochemical and isotopic features, compared to surface and ground waters in the watershed. The water pH is slightly acidic, and, compared to the other water samples from the watershed, shows an EC in the high range (57-1284μS/cm), the lowest pH and Eh values, and is Na-HCO 3 , whereas surface and ground waters are Ca(Mg)-HCO 3 type. The hot spring isotopic composition falls close to the Yangon Meteoric Water Line, indicating that, despite its temperature, it is not strongly modified by water-rock interaction processes. Preliminary results suggest that this hydrothermal water is likely related to deep meteoric and ground water circulation within a fault zone, in a region characterized by an elevated geothermal gradient

    Weathering geochemistry and Sr-Nd fingerprints of equatorial upper Nile and Congo muds

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    This study investigates processes of sediment generation in equatorial central Africa. An original, complete and integrated mineralogical-geochemical database on silt-sized sediments derived from different parent rocks (basalt, granite, gneiss, metapsammite, sandstone) along the East African Rift from 5°S in Tanzania to 5°N in Sudan is presented and used to assess the incidence of diverse factors controlling sediment composition (source-rock lithology, geomorphology, hydraulic sorting, grain size, recycling), with particular emphasis on chemical weathering

    Potentially Toxic Elements (PTEs) in Cultivated Soils from Lombardy (Northern Italy): Spatial Distribution, Origin, and Management Implications

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    This work aims to quantify the contribution of agricultural practices to diffuse pollution in cultivated soils. Two samples (the first from the top layer and the second from a depth of about 100 cm) were retrieved from about 1000 soil profiles and analyzed for their potentially toxic elements (PTEs) content (Cd, Cu, Ni, Pb, Zn, Mn). In addition, we collected dedicated soil profiles for three specific types of land use and agronomic practice, namely vine-, cereal- and rice-growing areas. Baseline concentrations and distribution maps were produced. Statistical data treatment, coupled with the results of the dedicated soil profiles, enabled the identification of precise pollution sources and processes. In cultivated soils, PTEs contents prove to be generally well below the Italian regulatory limits, with the exception of Cu in vineyard soils, due to the long-lasting use of Cu-based pesticides. South of Milan and in other urban areas, we attribute the top soil enrichment in Cd, Cu, Pb, and Zn to industrial activities and urban settlement. Ni sporadically exceeds regulatory standards, but its association with Mn and its depth distribution point to a natural origin, mostly due to the occurrence of serpentine. The project demonstrates that although agriculture, especially in the form of vineyards and of intensive cultivation, certainly contributes to pollution, such contribution is exceeded by that deriving from industry and road traffic

    Depósitos salinos naturales como promotores en la enseñanza­-aprendizaje

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    La enseñanza y el aprendizaje de la química en carreras universitarias con orientaciones no químicas se dificulta muchas veces por la falta de interés de los estudiantes hacia la disciplina. Los temas aplicados atraen la atención porque forman parte del contexto cotidiano, de estrecha relación con el entorno, en el cual quien estudia, aprende o enseña se encuentra inmersa. Un estudio aplicado a su vez otorga la posibilidad de usar activamente los conocimientos adquiridos. En este trabajo se partió de varios ecosistemas salinos naturales: Laguna Mar Chiquita, Córdoba, Laguna Epecuén, provincia Buenos Aires, y Laguna Guatraché, La Pampa, Argentina. Se tomaron muestras de depósitos salinos costeros localizados a diferentes distancias de la costa, más una muestra de agua de la laguna, a las cuales se analizó su composición química mediante difracción de rayos X, espectroscopía infrarroja y análisis químicos. Esta información se aportó a estudiantes de cursos de química general universitarios quienes trabajaron aspectos teóricos, con una guía de estudio, y llevaron a cabo una serie de ensayos experimentales sencillos, que les permitieron concluir sobre los distintos ecosistemas naturales y hacer una comparación entre los mismos.Facultad de Humanidades y Ciencias de la Educació

    The impact of mindfulness on psychosomatic complaints among firefighters: The mediator role of vicarious traumatisation

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    Firefighters are at risk to develop post-traumatic and psychosomatic symptoms. But in order to face negative health effects they have psychological resources at their disposal, such as mindfulness. This study aims to test the a model by which intrusion predicts general dysphoria in response to mindfulness. Self-report measures were administered to Italian firefighters. Structural equation modelling shown that mindfulness did not directly influence general dysphoria: mediation analyses revealed its meaningful indirect effect via intrusion. The results suggest that mindfulness can lead to reduced symptoms of general dysphoria through low levels of intrusive thoughts

    Proactive personality and training motivation among older workers

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    Purpose – This paper aims at examining the relationship between proactive personality and training motivation among older workers (aged over 55 years) in a context characterized by the growing ageing of the global population. First, the authors hypothesized that proactive personality predicts the motivation to learn among older workers and that this relationship is mediated by goal orientation. In particular, the authors hypothesized that learning goal orientation may mediate the relationship between proactive personality and learning motivation. Design/methodology/approach – The employees of an Italian bank completed an online questionnaire. AMOS 17 was used to carry out confirmatory factor analysis, and the SPSS macro was used to test the meditational model. Findings – The results confirmed both the hypotheses, demonstrating the influence of proactive personality on training motivation of older workers, as mediated by goal orientation and, in particular, by learning goal orientation. Practical implications – From an applicative point of view, this study may have implications for organizations that aim to increase the employability of older people by encouraging them to undertake more training. In particular, interventions aimed at increasing learning goal orientation could contribute in strengthening proactive personality that, in turn, may affect levels of training motivation. Originality/value – Even if proactive personality has already been found as a predictor of learning motivation, to the best of the authors’ knowledge, the present study demonstrates that the relationship between proactive personality and training motivation is mediated by goal orientation among older workers

    Entropy perturbations and large-scale magnetic fields

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    An appropriate gauge-invariant framework for the treatment of magnetized curvature and entropy modes is developed. It is shown that large-scale magnetic fields, present after neutrino decoupling, affect curvature and entropy perturbations. The evolution of different magnetized modes is then studied across the matter-radiation transition both analytically and numerically. From the observation that, after equality (but before decoupling) the (scalar) Sachs-Wolfe contribution must be (predominantly) adiabatic, constraints on the magnetic power spectra are deduced. The present results motivate the experimental analysis of more general initial conditions of CMB anisotropies (i.e. mixtures of magnetized adiabatic and isocurvature modes during the pre-decoupling phase). The role of the possible correlations between the different components of the fluctuations is partially discussed.Comment: 43 pages, 9 figure

    High sperm DNA fragmentation: do we have robust evidence to support antioxidants and testicular sperm extraction to improve fertility outcomes? a narrative review

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    To date, infertility affects 10% to 15% of couples worldwide. A male factor is estimated to account for up to 50% of cases. Oral supplementation with antioxidants could be helpful to improve sperm quality by reducing oxidative damage. At the same time, there is a growing interest in the literature on the use of testicular sperm in patients with high DNA fragmentation index (DFI). This narrative review aims to evaluate the effectiveness of supplementation of oral antioxidants in infertile men with high DFI compared to testicular sperm retrieval. The current evidence is non-conclusive because of serious risk of bias due to small sample sizes and statistical methods. Further large well-designed randomised placebo-controlled trials are still required to clarify the exact role of these to different therapeutic approaches

    Treatment with human, recombinant FSH improves sperm DNA fragmentation in idiopathic infertile men depending on the FSH receptor polymorphism p.N680S: A pharmacogenetic study

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    Study question: Does the spermDNAfragmentation index (DFI) improve depending on the FSH receptor (FSHR) genotype as assessed by the nonsynonymous polymorphisms rs6166 (p.N680S) after 3 months of recombinant FSH treatment in men with idiopathic infertility? summary answer: FSH treatment significantly improves sperm DFI only in idiopathic infertile men with the p.N680S homozygous N FSHR. what is known already: FSH, fundamental for spermatogenesis, is empirically used to treat male idiopathic infertility and several studies suggest that DFI could be a candidate predictor of response to FSH treatment, in terms of probability to conceive. Furthermore, it is known that the FSHR single nucleotide polymorphism (SNP) rs6166 (p.N680S) influences ovarian response in women and testicular volume in men. study design, size and duration: Amulticenter, longitudinal, prospective, open-label, two-arm clinical trial was performed. Subjects enrolled were idiopathic infertile men who received 150 IU recombinant human FSH s.c. every other day for 12 weeks and were followed-up for a further 12 weeks after FSH withdrawal. Patients were evaluated at baseline, at the end of treatment and at the end of follow-up. participants/materials, setting, methods: Eighty-nine men with idiopathic infertility carrier of the FSHR p.N680S homozygousNor S genotype, FSH 64 8 IU/l and DFI >15%,were enrolled. A total of 66 patients had DFI analysis completed on at least two visits. DFI was evaluated in one laboratory by TUNEL/PI (propidium iodide) assay coupled to flow cytometry, resolving two different fractions of sperm, namely the 'brighter' and 'dimmer' sperm DFI fractions. main results and the roleof chance: Thirty-eightmen(57.6%)were carriers of the p.N680S homozygousNand 28 (42.4%) of the homozygous S FSHR. Sperm concentration/number was highly heterogeneous and both groups included men ranging from severe oligozoospermia to normozoospermia. Total DFI was significantly lower at the end of the study in homozygous carriers of the p.N680SNversus p.N680S S allele (P = 0.008). Total DFI decreased significantly from baseline to the end of the study (P = 0.021) only in carriers of the p.N680S homozygous N polymorphism, and this decrease involved the sperm population containing vital sperm (i.e. brighter sperm) (P = 0.008). The dimmer sperm DFI fraction, including only nonvital sperm, was significantly larger in p.N680S S homozygous patients than in homozygous N men (P = 0.018). Total DFIwas inversely related to total sperm number (P = 0.020) and progressive sperm motility (P = 0.014).Whenpatients were further stratified according to sperm concentration (normoozospermic versus oligozoospermic) or -211G>T polymorphism in the FSHB gene (rs10835638) (homozygous Gversus others), the significant improvement of sperm DFI in FSHR p.N680S homozygousNmen was independent of sperm concentration and associated with the homozygous FSHB -211G>T homozygous G genotype. limitations, reasons for caution: The statistical power of the study is 86.9% with alpha error 0.05. This is the first pharmacogenetic study suggesting that FSH treatment induces a significant improvement of total DFI in men carriers of the p.N680S homozygousNFSHR; however, the results need to be confirmed in larger studies using a personalized FSH dosage and treatment duration. wider implications of the findings: The evaluation of sperm DFI as a surrogate marker of sperm quality, and of the FSHR SNP rs6166 (p.N680S), might be useful to predict the response to FSH treatment in men with idiopathic infertility. study funding/competing interest(s): The study was supported by an unrestricted grant to M.S. and H.M.B. from Merck Serono that provided the drug used in the study. MS received additional grants from Merck Serono and IBSA as well as honoraria from Merck Serono. The remaining authors declare that no conflicts of interest are present. trial registration number: EudraCT number 2010-020240-35
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