98 research outputs found

    Geometric reduction in optimal control theory with symmetries

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    A general study of symmetries in optimal control theory is given, starting from the presymplectic description of this kind of system. Then, Noether's theorem, as well as the corresponding reduction procedure (based on the application of the Marsden-Weinstein theorem adapted to the presymplectic case) are stated both in the regular and singular cases, which are previously described.Comment: 24 pages. LaTeX file. The paper has been reorganized. Additional comments have been included in Section 3. The example in Section 5.2 has been revisited. Some references have been adde

    The BLLAST field experiment: Boundary-Layer late afternoon and sunset turbulence

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    Due to the major role of the sun in heating the earth's surface, the atmospheric planetary boundary layer over land is inherently marked by a diurnal cycle. The afternoon transition, the period of the day that connects the daytime dry convective boundary layer to the night-time stable boundary layer, still has a number of unanswered scientific questions. This phase of the diurnal cycle is challenging from both modelling and observational perspectives: it is transitory, most of the forcings are small or null and the turbulence regime changes from fully convective, close to homogeneous and isotropic, toward a more heterogeneous and intermittent state. These issues motivated the BLLAST (Boundary-Layer Late Afternoon and Sunset Turbulence) field campaign that was conducted from 14 June to 8 July 2011 in southern France, in an area of complex and heterogeneous terrain. A wide range of instrumented platforms including full-size aircraft, remotely piloted aircraft systems, remote-sensing instruments, radiosoundings, tethered balloons, surface flux stations and various meteorological towers were deployed over different surface types. The boundary layer, from the earth's surface to the free troposphere, was probed during the entire day, with a focus and intense observation periods that were conducted from midday until sunset. The BLLAST field campaign also provided an opportunity to test innovative measurement systems, such as new miniaturized sensors, and a new technique for frequent radiosoundings of the low troposphere. Twelve fair weather days displaying various meteorological conditions were extensively documented during the field experiment. The boundary-layer growth varied from one day to another depending on many contributions including stability, advection, subsidence, the state of the previous day's residual layer, as well as local, meso- or synoptic scale conditions. Ground-based measurements combined with tethered-balloon and airborne observations captured the turbulence decay from the surface throughout the whole boundary layer and documented the evolution of the turbulence characteristic length scales during the transition period. Closely integrated with the field experiment, numerical studies are now underway with a complete hierarchy of models to support the data interpretation and improve the model representations.publishedVersio

    Mycorrhization of fagaceae forests within mediterranean ecosystems

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    Mediterranean Fagaceae forests are valuable due to their ecological and socioeconomic aspects. Some profitable plant species, such as Castanea (timber and chestnut), Quercus (timber and cork), and Fagus (timber), encounter in this habitat the excellent edaphoclimatic conditions to develop. All Fagaceae plants are commonly associated to ECM fungal species, which are found in these forests in quite stable communities, mainly enriched in Russulaceae and Telephoraceae species. Currently, the Mediterranean Basin is considered as one of the global biodiversity hotspots, since many of their endemic plant species are not found elsewhere and are now under threat. Due to climate changing and introduction of disease agents, Fagaceae forests are facing an adaptation challenge to both biotic and abiotic threats. Although ECM communities are highly disturbed by climate factors and tree disease incidence, they could play an important role in increasing water availability to the plant and also improving plant tree defense against pathogens. Recent advances, namely, on genomics and transcriptomics, are providing tools for increasing the understanding of Fagaceae mycorrhization process and stress responses to biotic and abiotic stresses. Such studies can provide new information for the implementation of the most adequate management policies for protecting threaten Mediterranean forests.info:eu-repo/semantics/publishedVersio

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Determinación de los coeficientes de variación diaria y horaria de la planta de tratamiento de aguas residuales de la ciudad del Cusco ubicado en el distrito de San Jerónimo y su relación con la calidad de agua de ingreso y salida.

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    TesisEl presente trabajo de investigación tiene por objetivo la determinación y cálculo de los valores de los coeficientes de variación diaria y horaria reales presentes en la Planta de Tratamiento de Aguas Residuales de la ciudad del Cusco ubicado en el distrito de San Jerónimo evaluados en los puntos de ingreso y salida de todo este sistema de tratamiento el cual viene funcionando desde el mes de febrero del año 2014, así como los valores de dos de los parámetros de calidad de agua como son la Demanda Bioquímica de Oxigeno y los Solidos Totales en Suspensión para la evaluación de la calidad de agua y el cumplimiento de las normas establecidas en nuestro país según el Ministerio del Ambiente para la evacuación de aguas residuales municipales tratadas. Para dicha investigación se realizó la medición de caudales in situ, apoyado por la lectura de los medidores automatizados de flujo ultrasónico; el primero realizado en el canal de ingreso y el segundo en el canal Parshall, empleando los conceptos de hidráulica y mecánica de fluidos para el cálculo de los caudales. Mientras que para la medición de la Demanda Bioquímica de Oxigeno y Solidos Totales en Suspensión se realizó la toma de muestras en los puntos planteados según el manual de monitoreo establecido por la Empresa Prestadora de Servicios SEDACUSCO realizando los procedimientos para los cálculos respectivos en el laboratorio acreditado de dicha empresa

    Quantitative flow ratio en infarto de miocardio para la evaluación de lesiones en arterias no culpables.: Estudio piloto QIMERA

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    Introduction and objectives: Complete revascularization is recommended for the management of ST-segment elevation myocardial infarctions (STEMI). Although physiological evaluation is recommended for the assessment of nonculprit lesions, in this context, the use of fractional flow reserve (FFR) is limited. The quantitative flow ratio (QFR) is a new angiography-based tool for the assessment of functional severity. We evaluated the functional changes occurring in nonculprit lesions after the acute phase and the QFR/FFR correlation in non-infarct-related arteries. Methods: We recruited all patients with multivessel disease admitted to our institution due to STEMI from January 2016 through December 2017 who underwent staged interventions for the management of nonculprit lesions. We conducted a retrospective QFR assessment at both the index and the staged procedures and drew a comparison. Also, the QFR/FFR concordance and agreement were prospectively evaluated between January and May 2018 in a cohort of patients with STEMI and multivessel disease. Results: We analyzed a total of 131 lesions in 88 patients. During the initial procedure, 93.1% of the lesions were considered significant based on the angiography compared to only 56.3% studied through QFR (P ≤ .001). The QFR reassessment during the staged intervention brought this percentage down to 32.1%. All patients with QFR values ≥ 0.82 during the index procedure remained nonsignificant at the staged assessment. Both the FFR and the QFR were compared in 12 patients showing good agreement and a mean difference of 0.015 ± 0.02 (P > .1). Conclusions: The QFR-based physiological assessment of nonculprit lesions in STEMI patients led us to consider nonsignificant 40% of the lesions classified as significant by the angiography. Also, the QFR significantly increased from the acute phase to the staged procedure, indicative that in patients with QFR ≥ 0.82 in the acute phase a new coronary angiography procedure may be unnecessary.Introducción y objetivos: En pacientes con infarto agudo de miocardio con elevación del segmento ST y enfermedad multivaso se recomienda la revascularización completa. La evaluación funcional con reserva fraccional de flujo (RFF) de las arterias no culpables del infarto es limitada. El quantitative flow ratio (QFR) es una herramienta basada en la angiografía para valorar la gravedad funcional de las lesiones. Se analizaron la evolución funcional de las arterias no culpables del infarto tras la fase aguda y la correlación QFR/RFF en este contexto. Métodos: Se incluyeron pacientes ingresados con infarto agudo de miocardio con elevación del segmento ST entre enero de 2016 y diciembre de 2017, con enfermedad multivaso y revascularización diferida de lesiones no culpables. Se evaluaron retrospectivamente con QFR durante el procedimiento índice y el diferido, y se evaluó la concordancia QFR/RFF de manera prospectiva entre enero y mayo de 2018. Resultados: Se incluyeron 131 lesiones de 88 pacientes. Durante el procedimiento índice, el 93,1% de las lesiones se consideraron significativas de acuerdo con la angiografía, pero solo el 56,3% cuando se evaluaron con QFR (p 0,1). Conclusiones: La evaluación fisiológica mediante QFR de las lesiones en arterias no culpables del infarto descartó la significación en el 40% de las consideradas significativas por angiografía. El valor de QFR se incrementó significativamente del procedimiento índice al diferido, lo que sugiere que en pacientes con QFR ≥ 0,82 en la fase aguda podrían evitarse procedimientos diferidos innecesarios

    CD4 T cell responses to influenza infection

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    Immune responses to viral infections involve a complex orchestration between innate signals and adaptive responses of specific T and B cells. Anti-viral CD4 cells can direct CD8 responses by secreting a Type 1 panel of cytokines including IFN-γ, IL-2 and TNF- α and can drive B cell production of IgG2a to neutralize infective viral particles. This review will focus specifically on the role of CD4 cells in the immune response to influenza, an acute, localized respiratory viral infection. We suggest that CD4 cells act as direct effectors in protection against influenza, may contribute to immunopathology and generate functionally distinct memory subsets
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