303 research outputs found

    Symmetry reduction, integrability and reconstruction in k-symplectic field theory

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    We investigate the reduction process of a k-symplectic field theory whose Lagrangian is invariant under a symmetry group. We give explicit coordinate expressions of the resulting reduced partial differential equations, the so-called Lagrange-Poincare field equations. We discuss two issues about reconstructing a solution from a given solution of the reduced equations. The first one is an interpretation of the integrability conditions, in terms of the curvatures of some connections. The second includes the introduction of the concept of a k-connection to provide a reconstruction method. We show that an invariant Lagrangian, under suitable regularity conditions, defines a `mechanical' k-connection.Comment: 37 page

    An Innovative Photovoltaic Luminescent Solar Concentrator Window: Energy and Environmental Aspects

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    Over the years, different types of smart windows have been tested and developed. In this study, an innovative prototype of a photovoltaic smart window, that integrates luminescent solar concentrators, was analysed. The device independently regulates the movement of the shading system and allows energy surplus, through the electricity generated by modules. Considering the peculiar structure (characterized by the presence of a light shelf) and the thermal characteristics of the device, the analyses focused on optical, thermal, and electrical performances, comparing them with those of a traditional window. The analysis followed an experimental approach that involved lighting and electrical monitoring studies in a real test room, to create validated models for conducting simulations in larger buildings. The results were expressed through the study of illuminance maps, electricity generation obtainable from the integrated photovoltaic technology and in terms of energy savings. Energy generation accounts for around 10 Wh/month, with up to 50% improvement from the perspective of energy use for heating and cooling. The technology proves effective in allowing efficient overall energy performances while generating enough energy to operate the smart window control systems

    Life Cycle Assessment of Luminescent Solar Concentrators Integrated into a Smart Window

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    The main goal of this paper is to assess the life cycle environmental impacts of a multifunctional smart window luminescent solar concentrator (SW-LSC) prototype through the application of the Life Cycle Assessment methodology. To the authors' knowledge, this is one of the first studies on the topic. The analysis followed a cradle to gate approach, considering the assembly and maintenance phase as well as the end of life, examined separately through a recycling/landfill scenario. A comparison of the impacts of LSC modules with those of some building-integrated photovoltaic technologies was carried out. Results showed that the global warming potential (100 years) for SW-LSC was 5.91 x 10(3) kg CO2eq and the manufacturing phase had the greatest impact (about 96%). The recycling/landfill scenario results showed the possibility to reduce impacts by an average of 45%. A dominance analysis of SW-LSC components showed that the aluminum frame was the main hotspot (about 60% contribution), followed by the light-shelf (about 19%). Batteries and motors for the shading system were the biggest contributors in the abiotic depletion potential category (36% and 30%, respectively). An alternative scenario, which involved the use of 75% recycled aluminum for the window frame, highlighted the possibility to reduce environmental impacts from 3% to 46%. Finally, the comparison results showed that the LSC modules' impacts were on average 870% lower than that of various PV technologies when compared on the basis of m(2); on the contrary, LSC modules had the highest impacts in all categories (from 200% to 1900%) when compared with other PV technologies on the basis of 1 kWh of energy generated. The results could be used for the definition of eco-design strategies for the examined device, in order to support the scaling-up process and to put "greener" systems onto the market

    Gene discovery in Triatoma infestans

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    Background: Triatoma infestans is the most relevant vector of Chagas disease in the southern cone of South America. Since its genome has not yet been studied, sequencing of Expressed Sequence Tags ( ESTs) is one of the most powerful tools for efficiently identifying large numbers of expressed genes in this insect vector. Results: In this work, we generated 826 ESTs, resulting in an increase of 47% in the number of ESTs available for T. infestans. These ESTs were assembled in 471 unique sequences, 151 of which represent 136 new genes for the Reduviidae family. Conclusions: Among the putative new genes for the Reduviidae family, we identified and described an interesting subset of genes involved in development and reproduction, which constitute potential targets for insecticide development

    The Ramazzini Institute 13-week study on glyphosate-based herbicides at human-equivalent dose in Sprague Dawley rats: Study design and first in-life endpoints evaluation

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    Background: Glyphosate-based herbicides (GBHs) are the most widely used pesticides worldwide, and glyphosate is the active ingredient of such herbicides, including the formulation known as Roundup. The massive and increasing use of GBHs results in not only the global burden of occupational exposures, but also increased exposure to the general population. The current pilot study represents the first phase of a long-term investigation of GBHs that we are conducting over the next 5 years. In this paper, we present the study design, the first evaluation of in vivo parameters and the determination of glyphosate and its major metabolite aminomethylphosphonic acid (AMPA) in urine. Methods: We exposed Sprague-Dawley (SD) rats orally via drinking water to a dose of glyphosate equivalent to the United States Acceptable Daily Intake (US ADI) of 1.75 mg/kg bw/day, defined as the chronic Reference Dose (cRfD) determined by the US EPA, starting from prenatal life, i.e. gestational day (GD) 6 of their mothers. One cohort was continuously dosed until sexual maturity (6-week cohort) and another cohort was continuously dosed until adulthood (13-week cohort). Here we present data on general toxicity and urinary concentrations of glyphosate and its major metabolite AMPA. Results: Survival, body weight, food and water consumption of the animals were not affected by the treatment with either glyphosate or Roundup. The concentration of both glyphosate and AMPA detected in the urine of SD rats treated with glyphosate were comparable to that observed in animals treated with Roundup, with an increase in relation to the duration of treatment. The majority of glyphosate was excreted unchanged. Urinary levels of the parent compound, glyphosate, were around 100-fold higher than the level of its metabolite, AMPA. Conclusions: Glyphosate concentrations in urine showed that most part of the administered dose was excreted as unchanged parent compound upon glyphosate and Roundup exposure, with an increasing pattern of glyphosate excreted in urine in relation to the duration of treatment. The adjuvants and the other substances present in Roundup did not seem to exert a major effect on the absorption and excretion of glyphosate. Our results demonstrate that urinary glyphosate is a more relevant marker of exposure than AMPA in the rodent model

    Effect of Support Supervision on Maternal and Newborn Health Services and Practices in Rural Eastern Uganda

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    Background: Support supervision is one of the strategies used to check the quality of services provided at health facilities. From 2013 to 2015, Makerere University School of Public Health strengthened support supervision in the district of Kibuku, Kamuli and Pallisa in Eastern Uganda to improve the quality of maternal and newborn services. Objective: This article assesses quality improvements in maternal and newborn care services and practices during this period. Methods: District management teams were trained for two days on how to conduct the supportive supervision. Teams were then allocated particular facilities, which they consistently visited every quarter. During each visit, teams scored the performance of each facility based on checklists; feedback and corrective actions were implemented. Support supervision focused on maternal health services, newborn care services, human resources, laboratory services, availability of Information, education and communication materials and infrastructure. Support supervision reports and checklists from a total of 28 health facilities, each with at least three support supervision visits, were analyzed for this study and 20 key-informant interviews conducted. Results: There was noticeable improvement in maternal and newborn services. For instance, across the first, second and third quarters, availability of parenteral oxytocin increased from 57% to 75% and then to 82%. Removal of retained products increased from 14% to 50% to 54%, respectively. There was perceived improvement in the use of standards and guidelines for emergency obstetric care and quality of care provided. Qualitatively, three themes were identified that promote the success of supportive supervision: changes in the support supervision style, changes in the adherence to clinical standards and guidelines, and multi-stakeholder engagement. Conclusion: Support supervision helped district health managers to identify and address maternal and newborn service-delivery gaps. However, issues beyond the jurisdiction of district health managers and facility managers may require additional interventions beyond supportive supervision.DFI

    Characteristics of community savings groups in rural Eastern Uganda: opportunities for improving access to maternal health services

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    Background: Rural populations in Uganda have limited access to formal financial Institutions, but a growing majority belong to saving groups. These saving groups could have the potential to improve household income and access to health services. Objective: To understand organizational characteristics, benefits and challenges, of savings groups in rural Uganda. Methods: This was a cross-sectional descriptive study that employed both quantitative and qualitative data collection techniques. Data on the characteristics of community-based savings groups (CBSGs) were collected from 247 CBSG leaders in the districts of Kamuli, Kibukuand Pallisa using self-administered open-ended questionnaires. To triangulate the findings, we conducted in-depth interviews with seven CBSG leaders. Descriptive quantitative and content analysis for qualitative data was undertaken respectively. Results: Almost a quarter of the savings groups had 5–14 members and slightly more than half of the saving groups had 15–30 members. Ninety-three percent of the CBSGs indicated electing their management committees democratically to select the group leaders and held meetings at least once a week. Eighty-nine percent of the CBSGs had used metallic boxes to keep their money, while 10% of the CBSGs kept their money using mobile money and banks, respectively. The main reasons for the formation of CBSGs were to increase household income, developing the community and saving for emergencies. The most common challenges associated with CBSG management included high illiteracy (35%) among the leaders, irregular attendance of meetings (22%), and lack of training on management and leadership (19%). The qualitative findings agreed with the quantitative findings and served to triangulate the main results. Conclusions: Saving groups in Uganda have the basic required structures; however, challenges exist in relation to training and management of the groups and their assets. The government and development partners should work together to provide technical support to the groups

    Timing of Symptoms of Early-Onset Sepsis after Intrapartum Antibiotic Prophylaxis: Can It Inform the Neonatal Management?

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    The effectiveness of “inadequate” intrapartum antibiotic prophylaxis (IAP administered < 4 h prior to delivery) in preventing early-onset sepsis (EOS) is debated. Italian prospective surveillance cohort data (2003–2022) were used to study the type and duration of IAP according to the timing of symptoms onset of group B streptococcus (GBS) and E. coli culture-confirmed EOS cases. IAP was defined “active” when the pathogen yielded in cultures was susceptible. We identified 263 EOS cases (GBS = 191; E. coli = 72). Among GBS EOS, 25% had received IAP (always active when beta-lactams were administered). Most IAP-exposed neonates with GBS were symptomatic at birth (67%) or remained asymptomatic (25%), regardless of IAP duration. Among E. coli EOS, 60% were IAP-exposed. However, IAP was active in only 8% of cases, and these newborns remained asymptomatic or presented with symptoms prior to 6 h of life. In contrast, most newborns exposed to an “inactive” IAP (52%) developed symptoms from 1 to >48 h of life. The key element to define IAP “adequate” seems the pathogen’s antimicrobial susceptibility rather than its duration. Newborns exposed to an active antimicrobial (as frequently occurs with GBS infections), who remain asymptomatic in the first 6 h of life, are likely uninfected. Because E. coli isolates are often unsusceptible to beta-lactam antibiotics, IAP-exposed neonates frequently develop symptoms of EOS after birth, up to 48 h of life and beyond
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