49 research outputs found
Neutron spectra and H*(10) around an 18 MV LINAC by ANNs
Neutron spectra and ambient dose equivalent H*(10) were calculated for a radiotherapy room in
16 point-like detectors, 15 located inside the vault room and 1 located outside the bunker. The
calculation was carried out using Monte Carlo Methods with the MCNP5 code for a generic
radiotherapy room model operating with a 18 MV Linac, obtaining 16 neutron spectra with 47
energy bins, the H*(10) values were calculated from the neutron spectra by the use of the
fluence-dose conversion factors. An Artificial Neural Network (ANN) were designed and trained
to determine the neutron H*(10) in 15 different locations inside the vault room from the H*(10)
dose calculated for the detector located outside the room, using the calculated dose values as
training set, using the scaled conjugated gradient training algorithm The mean squared error
(mse) set for the network training was 1E(-14), adjusting the data in 99.992 %. In the treatment
hall, as the distance respect to the isocenter is increased, the amount of neutrons and the H*(10)
are reduced, neutrons in the high-energy region are shifted to lower region peaking around 0.1
MeV, however the epithermal and thermal neutrons remain constant due to the room-return
effect. In the maze the spectra are dominated by epithermal and thermal neutrons that contributes
to produce activation and the production of prompt gamma-rays. The results shows the using this
Artificial Intelligence technic as a useful tool for the neutron spectrometry and dosimetry by the
simplification on the neutronic fields characterization inside radiotherapy rooms avoiding the use
of traditional spectrometric systems. And once the H*(10) doses have been calculated, to take the
appropriated actions to reduce or prevent the patient and working staff exposure to this
undesirable neutron radiatio
Neutron area monitor with passive detector
Using Monte Carlo methods the responses of a passive neutron monitor area has been calculated. To detect thermal neutrons the monitor has a gold foil that is located at the center of a polyethylene cylinder. Impinging neutrons are moderated by polyethylene nuclei reaching the gold foil with the energy to induce activation through the reaction 197Au (n,γ) 198Au. The198Au decays emitting 0.411 MeV gamma rays with a half life of 2.7 days. The induced activity is intended to be measured with a gamma-ray spectrometer with a 3”Ø×3” NaI(Tl) scintillator and the saturation activity is correlated to the ambient dose equivalent. The response was calculated for 47 monoenergetic neutron sources ranging from 1×10−9 to 20 MeV. Calculated fluence response was compared with the response of neutron monitor area LB 6411. = Se utilizó el método de Monte Carlo para calcular las respuestas de un monitor de neutrones pasivo. Para detectar los neutrones térmicos el monitor tiene una lámina de oro que se encuentra en el centro de un cilindro de polietileno. Los neutrones que inciden son moderados por los núcleos de polietileno que llega a la lámina de oro con la energía para inducir la activación a través de la 197Au reacción (n,γ)198 Au. El 197Au decae emitiendo rayos gamma de 0.411 MeV con una vida media de 2.7 días. La actividad inducida se destina a medir con un espectrómetro de rayos gamma con un detector de centelleo de 3”Ø×3” NaI (Tl) y la actividad de saturación se correlaciona con la dosis equivalente ambiental. La respuesta se calculó para 47 fuentes de neutrones monoenergéticos desde 1×10−9 a 20 MeV. La respuesta a la fluencia se comparó con la respuesta del monitor de área LB 6411
Passive neutron area monitor with TLD pairs
The response of a passive neutron area monitor with pairs of thermoluminescent dosimeters has been calculated using the Monte Carlo code MCNP5. The response was calculated for one TLD 600 located at the center of a polyethylene moderator. The response was calculated for 47 monoenergetic neutron sources ranging from 1E(-9) to 20 MeV. Response was calculated using two irradiation geometries, one with an
upper source and another with a lateral source. For both irradiation schemes the response was calculated with the TLD in two positions, one parallel to the source and another perpendicular to the source. The advantage of this passive neutron monitor area is that can be used in locations with intense, pulsed and mixed radiation fields like those in radiotherapy vault rooms with linear accelerators.
La respuesta de un monitor de área pasivo para neutrones con pares de dosímetros termoluminiscentes TLDs ha sido calculada mediante métodos Montecarlo con el código MCNP5. La respuesta fue calculada para un TLD 600 localizado en el centro del moderador cilíndrico de polietileno. La respuesta se calculó para 47 fuentes mono energéticas de neutrones con energías de 1E (-9) a 20 MeV. La respuesta se calculó para dos geometrías de irradiación, una con una fuente superior y la otra con una fuente lateral, para ambas geometrías la respuesta se obtuvo con el TLD en dos posiciones respecto a la fuente, una perpendicular y la otra paralela. La ventaja del monitor pasivo es que puede ser usado en instalaciones con campos de radiación intensos, pulsados y mixtos como los que se producen en los bunkers de radioterapia con aceleradores lineales
The Mont-Blanc prototype: an alternative approach for high-performance computing systems
High-performance computing (HPC) is recognized as one of the pillars for further advance of science, industry, medicine, and education. Current HPC systems are being developed to overcome emerging challenges in order to reach Exascale level of performance,which is expected by the year 2020. The much larger embedded and mobile market allows for rapid development of IP blocks, and provides more flexibility in designing an application-specific SoC, in turn giving possibility in balancing performance, energy-efficiency and cost. In the Mont-Blanc project, we advocate for HPC systems be built from such commodity IP blocks, currently used in embedded and mobile SoCs.
As a first demonstrator of such approach, we present the Mont-Blanc prototype; the first HPC system built with commodity SoCs, memories, and NICs from the embedded and mobile domain, and off-the-shelf HPC networking, storage, cooling and integration solutions. We present the system’s architecture, and evaluation including both performance and energy efficiency. Further, we compare the system’s abilities against a production level supercomputer. At the end, we discuss parallel scalability, and estimate the maximum scalability point of this approach across a set of HPC applications.Postprint (published version
Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study
Background: Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies. Methods: For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia. Findings: Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified. Interpretation: Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life
ARIA digital anamorphosis: Digital transformation of health and care in airway diseases from research to practice
Digital anamorphosis is used to define a distorted image of health and care that may be viewed correctly using digital tools and strategies. MASK digital anamorphosis represents the process used by MASK to develop the digital transformation of health and care in rhinitis. It strengthens the ARIA change management strategy in the prevention and management of airway disease. The MASK strategy is based on validated digital tools. Using the MASK digital tool and the CARAT online enhanced clinical framework, solutions for practical steps of digital enhancement of care are proposed
Anomalies thymiques de la voie Rel/NF-KappaB dans l'auto-immunité
AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF
Impacto económico del dengue y del dengue hemorrágico en el Estado de Zulia, Venezuela, 1997-2003 Economic impact of dengue and dengue hemorrhagic fever in the State of Zulia, Venezuela, 1997-2003
OBJETIVOS: Determinar los costos directos e indirectos asociados con la atención de los casos de dengue y de dengue hemorrágico o síndrome de choque por dengue (DH/SCD) entre los años 1997 y 2003 en el Estado de Zulia, Venezuela. MÉTODOS: El número total de pacientes con dengue y DH/SCD se obtuvo de los registros de la Dirección Regional de Epidemiología del Estado de Zulia y de los informes de casos confirmados en la Sección de Virología del Instituto de Investigaciones Clínicas Dr. Américo Negrette, de la Facultad de Medicina, Universidad del Zulia, Maracaibo, entre el 1.° de enero de 1997 y el 31 de diciembre de 2003. Como costos directos se consideraron el costo de la atención médica de urgencia de todos los casos y los costos de hospitalización de los casos con DH/SCD (costo por día-cama y costos de laboratorio). Los costos asociados con la ausencia laboral de los enfermos mayores de 15 años y de las madres acompañantes de los enfermos menores de 15 años conformaron los costos indirectos, ajustados según la proporción de hombres y mujeres en la fuerza laboral activa del país. Para el cálculo se utilizó el salario mínimo anual y los resultados se expresaron en dólares estadounidenses, según la tasa de cambio promedio de cada año. RESULTADOS: En el período estudiado se atendieron 33 857 casos de dengue y de DH/SCD; de ellos, 30 251 (89,35%) fueron de dengue y 3 606 (10,65%) de DH/SCD. Seis de estos fallecieron (letalidad 0,2 por 100 casos de DH/SCD). Los costos directos fueron US 132 042,30 correspondieron a la atención en los servicios de urgencia y US 873 825,84 y representaron 64,8% del gasto total (US 474 251.70; of these costs, US 342 209.40 on the hospital costs of DHF/DSS cases. Indirect costs were US 1 348 077.54) connected to this disease during the study years. CONCLUSIONS: This is the first study on the economic impact of dengue in the state of Zulia and in Venezuela. In spite of some limitations, results show that dengue is an important public health problem that causes great expense because of temporary absenteeism from work and that undermines regional and national economic development
ESPAT Vers une estimation des précipitations par satellite au Sahel EPSAT-Niger : campagne 1990
La saison des pluies 1990 a été déficitaire presque partout au Sahel et la zone étudiée (environ 10 000 km2), autour de Niamey, n'est pas une exception. Sur le plan expérimental, le réseau de pluviographes a été fiable, tandis que la chaîne radar a été fragile. A l'aval des acquisitions ont été développées des banques de données sol (BADINAGE) et radar (BADORA). (Résumé d'auteur