258 research outputs found
Software Process Simulation Modeling: Systematic literature review
Changes and continuous progress in logistics and productive systems make the realization of improvements in
decision making necessary. Simulation is a good support tool for this type of decisions because it allows reproducing
processes virtually to study their behavior, to analyze the impact of possible changes or to compare
different design alternatives without the high cost of scale experiments. Although process simulation is usually
focused on industrial processes, over the last two decades, new proposals have emerged to bring simulation
techniques into software engineering. This paper describes a Systematic Literature Review (SLR) which returned
8070 papers (published from 2013 to 2019) by a systematic search in 4 digital libraries. After conducting this
SLR, 36 Software Process Simulation Modeling (SPSM) works were selected as primary studies and were
documented following a specific characterization scheme. This scheme allows characterizing each proposal
according to the paradigm used and its technology base as well as its future line of work. Our purpose is to
identify trends and directions for future research on SPSM after identifying and studying which proposals in this
topic have been defined and the relationships and dependencies between these proposals in the last five years.
After finishing this review, it is possible to conclude that SPSM continues to be a topic that is very much
addressed by the scientific community, but each contribution has been proposed with particular goals. This
review also concludes that Agent-Based Simulation and System Dynamics paradigm is increasing and decreasing,
respectively, its trend among SPSM proposals in the last five years. Regarding Discrete-Event Simulation paradigm,
it seems that it is strengthening its position among research community in recent years to design new
approaches.Ministerio de Economía y Competitividad TIN2016-76956-C3-2-
Lithospheric contraction concentric to Tharsis: 3D structural modeling of large thrust faults between Thaumasia highlands and Aonia Terra, Mars
Large thrust faults on Mars are caused by lithospheric planetary contraction. The geometry of these faults is linked with the mechanical behavior of the lithosphere. Tharsis, the largest volcano-tectonic province on Mars, controls the global tectonic pattern of the planet. Here, we present a study of five large thrust faults concentric to Tharsis, located between the Thaumasia Highlands and the Argyre impact basin. We applied a 3D structural modeling, using a combination of fault-parallel flow and trishear algorithms to estimate the geometry and kinematics of the faults at depth. The modeled faults show an upper planar part dipping 33° to 40°, rooting with a listric geometry into horizontal levels at 13–27 km depth, with fault slips of 801–3366 m. The general out-of-Tharsis vergence, the listric fault geometries and the deepening of the depth of faulting toward Thaumasia outline an incipient thrust wedge architecture. Assuming that the largest faults rooted at the Brittle-Ductile Transition, we calculate a heat flow at the time of faulting of 24–54 mW m−2. The obtained strength envelopes for dry and wet conditions show that all the strength of the lithosphere was located in the upper half of the crust.This research has been supported by the project TECTOMARS PGC2018-095340-B-I00, funded by the Spanish Ministry of Science, Innovation and Universities
Present-day and early heat flows and the thermal evolution of Mars
Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu
Evolving spectrum but persistent high mortality of COVID-19 among patients on kidney replacement therapy in the vaccine era: the Spanish COVID-19 KRT Registry
COVID-19; Kidney transplant; DialysisCOVID-19; Trasplantament de ronyó; DiàlisiCOVID-19; Trasplante de riñón; DiálisisBackground
Kidney replacement therapy (KRT) conferred a high risk for coronavirus disease 2019 (COVID-19) related mortality early in the pandemic. We evaluate the presentation, treatment and outcomes of COVID-19 in patients on KRT over time during the pandemic.
Methods
This registry-based study involved 6080 dialysis and kidney transplant (KT) patients with COVID-19, representing roughly 10% of total Spanish KRT patients. Epidemiology, comorbidity, infection, vaccine status and treatment data were recorded, and predictors of hospital admission, intensive care unit (ICU) admission and mortality were evaluated.
Results
Vaccine introduction decreased the number of COVID-19 cases from 1747 to 280 per wave. Of 3856 (64%) COVID-19 KRT patients admitted to the hospital, 1481/3856 (38%) were admitted during the first of six waves. Independent predictors for admission included KT and the first wave. During follow-up, 1207 patients (21%) died, 500/1207 (41%) during the first wave. Among vaccinated patients, mortality was 19%, mostly affecting KT recipients. Overall, independent predictors for mortality were older age, disease severity (lymphopaenia, pneumonia) and ICU rejection. Among patient factors, older age, male sex, diabetes, KT and no angiotensin receptor blockers (ARB) were independent predictors of death. In KT recipients, individual immunosuppressants were independent predictors of death. Over time, patient characteristics evolved and in later pandemic waves, COVID-19 was mainly diagnosed in vaccinated KT recipients; in the few unvaccinated dialysis patients, ICU admissions increased and mortality decreased (28% for the first wave and 16–22% thereafter).
Conclusions
The clinical presentation and outcomes of COVID-19 during the first wave no longer represent COVID-19 in KRT patients, as the pandemic has become centred around vaccinated KT recipients. Vaccines lowered the incidence of diagnosed COVID-19 and mortality. However, mortality remains high despite increased access to ICU care.We want to thank all the implicated Spanish centres for their altruist collaboration. A.O. research is supported by FIS/Fondos FEDER [PI18/01366, PI19/00588, PI19/00815, DTS18/00032, ERA-PerMed-JTC2018 (KIDNEY ATTACK AC18/00064 and PERSTIGAN AC18/00071, ISCIII-RETIC REDinREN RD016/0009)], Sociedad Española de Nefrología, FRIAT, Comunidad de Madrid en Biomedicina B2017/BMD-3686 CIFRA2-CM. Instituto de Salud Carlos III (ISCIII) RICORS program to RICORS2040 (RD21/0005/0001), FEDER funds
Validation of surrogate anthropometric indices in older adults: what is the best indicator of high cardiometabolic risk factor clustering?
Incluye correccionesThe present study evaluated the ability of five obesity-related parameters, including a body shape index (ABSI), conicity index (CI), body roundness index (BRI), body mass index (BMI), and waist-to-height ratio (WtHR) for predicting increased cardiometabolic risk in a population of elderly Colombians. A cross-sectional study was conducted on 1502 participants (60.3% women, mean age 70 ± 7.6 years) and subjects’ weight, height, waist circumference, serum lipid indices, blood pressure, and fasting plasma glucose were measured. A cardiometabolic risk index (CMRI) was calculated using the participants’ systolic and diastolic blood pressure, triglycerides, high-density lipoprotein and fasting glucose levels, and waist circumference. Following the International Diabetes Federation definition, metabolic syndrome was defined as having three or more metabolic abnormalities. All surrogate anthropometric indices correlated significantly with CMRI (p < 0.01). Receiver operating characteristic curve analysis of how well the anthropometric indices identified high cardiometabolic risk showed that WtHR and BRI were the most accurate indices. The best WtHR and BRI cut-off points in men were 0.56 (area under curve, AUC 0.77) and 4.71 (AUC 0.77), respectively. For women, the WtHR and BRI cut-off points were 0.63 (AUC 0.77) and 6.20 (AUC 0.77), respectively. In conclusion, BRI and WtHR have a moderate discriminating power for detecting high cardiometabolic risk in older Colombian adults, supporting the idea that both anthropometric indices are useful screening tools for use in the elderly
Calcineurin inhibitors cyclosporine A and tacrolimus induce vascular inflammation and endothelial activation through TLR4 signaling
The introduction of the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus greatly reduced the
rate of allograft rejection, although their chronic use is marred by a range of side effects, among them
vascular toxicity. In transplant patients, it is proved that innate immunity promotes vascular injury
triggered by ischemia-reperfusion damage, atherosclerosis and hypertension. We hypothesized that
activation of the innate immunity and inflammation may contribute to CNI toxicity, therefore we
investigated whether TLR4 mediates toxic responses of CNIs in the vasculature. Cyclosporine and
tacrolimus increased the production of proinflammatory cytokines and endothelial activation markers
in cultured murine endothelial and vascular smooth muscle cells as well as in ex vivo cultures of murine
aortas. CNI-induced proinflammatory events were prevented by pharmacological inhibition of TLR4.
Moreover, CNIs were unable to induce inflammation and endothelial activation in aortas from TLR4−/−
mice. CNI-induced cytokine and adhesion molecules synthesis in endothelial cells occurred even in the
absence of calcineurin, although its expression was required for maximal effect through upregulation
of TLR4 signaling. CNI-induced TLR4 activity increased O2
−/ROS production and NF-κB-regulated
synthesis of proinflammatory factors in cultured as well as aortic endothelial and VSMCs. These data
provide new insight into the mechanisms associated with CNI vascular inflammationThis work was supported by grants from the Instituto de Salud Carlos III (Ministerio de Economía Competitividad, Gobierno de España): FEDER funds ISCIII RETIC REDINREN RD12/0021, PI11/02242, PI13/00047, PI14/0041, PI14/00386, PI15/01460; Comunidad de Madrid (CIFRA S2010/BMD-2378); Sociedad Española de Nefrología. Salary support: RR-D:
CIFRA; CO-S: Fundación Conchita Rábago de Jiménez Díaz; CG-G and RRR-D: REDINREN; AO: Programa Intensificación Actividad Investigadora (ISCIII/Agencia Laín-Entralgo/CM); JE and MRO: Universidad Autónoma de Madrid; AMR: Contrato Miguel Serve (ISCIII
Climate and subsurface sea temperature in Bahía Culebra, Costa Rica
Artículo científico -- Universidad de Costa Rica. Centro de Investigaciones Científicas, 2012Bahía Culebra, Golfo de Papagayo, Costa Rica is a seasonal upwelling area. To determine the relationship of climate and the subsurface temperature variability at Bahía Culebra, we analyzed nine records of sea subsurface temperature from the Bay, continuously recorded from 1998 to 2010. The analysis characterized the annual cycle and explored the influence of different climate variability sources on the subsurface sea temperature and air temperature recorded in Bahía Culebra. Data from an automatic meteorological station in the bay were studied, obtaining the annual and daily cycle for air surface temperature and wind speed. Sea surface temperature (SST) trend from 1854 to 2011 was calculated from reanalysis for the region that coverts 9-11°N, 85-87°W. Because of the positive SST trend identified in this region, results showed that annual and daily cycles in Bahía Culebra should be studied under a warming scenario since 1854, that is coherent with the global warming results and its climate variability is influenced by El Niño-Southern Oscillation (ENSO) in the Equatorial Pacific and by atmospheric forcing triggered by climate variability with Atlantic Ocean origin, because warm (cold) events in Bahía Culebra tend to occur in concordance with positive & negative (negative & positive) anomalies in Niño 3.4 (NAO) index. Rev. Biol. Trop. 60 (Suppl. 2): 159-171. Epub 2012 April 01.Bahía Culebra, Golfo de Papagayo, Costa Rica es una región de afloramiento estacional. Para determinar la relación entre el clima y la variabilidad de la temperatura sub-superficial, se analizaron los registros de la temperatura sub-superficial del mar de nueve estaciones localizadas en la Bahía. El análisis permitió caracterizar su ciclo anual y explorar su relación con fuentes de variabilidad climática que influencian el clima regional para el periodo 1998- 2010. Los resultados se contextualizaron usando además los datos de una estación meteorológica automática que funcionó en la bahía junto con el registro de la temperatura superficial del mar para una rejilla que cubre la región de 9-11°N, 85-87°W, para el periodo 1854-2011. Debido a la tendencia positiva encontrada en la región para la temperatura superficial del mar, se concluye que los resultados mostrados asociados a los ciclos anuales y diarios en Bahía Culebra deben ser interpretados bajo un escenario de cambio climático, asociado a un calentamiento ocurrido desde 1854, además coherente con lo observado globalmente, y que su variabilidad climática está influenciada no sólo por aquella ligada a la de El Niño-Oscilación del Sur, en el Pacífico Ecuatorial, sino también por influencias de tipo atmosférico relacionadas con la variabilidad en el Océano Atlántico, debido a que los eventos cálidos (fríos) en Bahía Culebra tienden a ocurrir en concordancia con anomalías positivas y negativas (negativas y positivas) de los índices Niño 3.4 y OAN, respectivamente.Universidad de Costa Rica. El estudio se realizó dentro del marco de los siguientes proyectos de la Vicerrectoría de Investigación de la Universidad de Costa Rica: 808-98-013, 808-B0-092, 805-B0-065, 805-A9- 532, 808-A9-180, 808-A9-070, 805-A8-606, 805-A7-002 y 808-B2-400, y CRN2050-IAI. El apoyo dado por Ecodesarrollo Papagayo ha sido invaluable para mantener este programa de monitoreo por todos estos años. Le agradecemos a todos los asistentes que han colaborado durante los años de este programa de monitoreo. Al Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) de la Universidad de Costa Rica se le agradece el apoyo logístico, y al Instituto Costarricense de Turismo por el uso de las instalaciones en Playa Panamá, Bahía Culebra. También a Laura Zúñiga, Natalie Mora, Aarón Vega y Elsie Troyo por su apoyo en el procesamiento de la información y la base de datos. A Vilma Castro por el aporte y asistencia de la estación meteorológica automática localizada en Playa Panamá.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI
Hydrodynamic Analysis on a Photocatalytic Reactor Using ANSYS Fluent<sup>®</sup>
Solar technology includes a wide variety of developments in environmental applications that include photovoltaic cells and photocatalytic devices, among others. Sunlight usage as a clean energy source is highly desirable in technology applications. The main interest of this proposal is to carry on with hydrodynamic analysis in photocatalytic reactors applications where sunlight is used to activate a chemical reaction to degrade water pollutants and calculations are based in computational fluid dynamics (CFD) using ANSYS®. The different steps, geometric domain, preprocessing steps, setup, and postprocessing steps, are described to display an analysis of a numerical calculation during the design of a photocatalytic reactor using the commercial software ANSYS Fluent®. This work may help as a guide for chemical reactor design and includes a numerical solution of one case for a photocatalytic reactor during its design process. In addition, simplifications are explained which enable the designer to make an efficient process of the numerical calculation. Calculations and analysis are carried over in ANSYS Fluent® a powerful multi-physics program suite to develop photocatalytic reactors
Uso de evaluación continua para incrementar la motivación del alumnado en asignaturas de Ingeniería
The guided and evaluated learning at the end of the course is a vestige inherited from the old curricula. With the reduction of the number of students, as well as with the implementation of the new curricula, the teaching system has to be changed, turning towards a way in which the student is the main actor and the teacher carries out a continuous feedback (guided process). In the present research it has been shown that the continued work of students, with real problems associated with Engineering, allows the learning process to be carried out with a greater motivation and, therefore, involvement by the students, improving their academic performanceEl aprendizaje guiado y evaluado al final del curso es un vestigio heredado de los antiguos planes de estudios. Con la reducción del número de alumnos, así como con la implementación de los nuevos planes de estudio se hace necesario cambiar el sistema de enseñanza, virando hacia un modeo en el que el alumno sea el protagonista y que el profesor lleve a cabo un proceso de retroalimentación (guiado) continuado. En el presente estudio queda demostrado que el trabajo continuo de los alumnos con problemas reales asociados a la Ingeniería permite que el proceso de aprendizaje lleve acarreado una mayor motivación y, por ende, implicación por parte de los estudiantes, mejorando el rendimiento de los mismos.Universidad de Sevilla. Ayuda 1.2.3 del III Plan Propio de Docenci
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