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A mediados del 2018 un grupo de investigadores e investigadoras del Centro de Investigaciones Geofísicas y de la Escuela de Física de la Universidad de Costa Rica iniciaron un proyecto para compartir conocimientos sobre las ciencias del tiempo y el clima con la comunidad cabécar de Pú Ksogë (9.591°N, 82.978°W, 114.4 m s. n. m.), Talamanca, Limón. La iniciativa fue apoyada por líderes y autoridades educativas de esa comunidad indígena a finales de ese año. Con el aporte laboral local y la autorización respectiva, se instaló y dejó en operación una estación meteorológica automática (Siwá Etka) en terrenos de la escuela comunal a principios de 2019. Se describen aquí detalles de este proyecto y se muestran los primeros datos atmosféricos observados en la historia de esa comunidad.La falta de un adecuado control comunal y el desinterés de las autoridades de la escuela en el cuido del instrumental provocaron problemas que no permitieron darle continuidad al proyecto y la estación tuvo que ser desinstalada en octubre de 2019. La experiencia tuvo resultados positivos, pero otros aspectos como la conectividad a celular e internet, en ocasiones de muy baja calidad o inexistente, también incidieron en la decisión de descontinuar la iniciativa. Los contactos realizados con una asociación de desarrollo integral de la región podrían ser una alternativa para darle continuidad al proyecto.

Understanding ecohydrological dynamics that result from land-use conversions is fundamental in managing ecosystem services. One common forest transformation in the tropics is the establishment of monospecific plantations with exotic species for timber exploitation, replacing highly diverse natural forests. The impacts of establishing forest plantations in hydrological processes and biogeochemical dynamics, have been highly controversial, with functions from structurally homogeneous plantations being sometimes assumed to be comparable to natural forests. To assess the effects of planting exotic conifer species versus natural forests on hydrological and biogeochemical functions, we measured incoming precipitation, throughfall and stemflow. To compare between forest types, we propose the use of basal area for standardization of hydrochemical fluxes. While net precipitation was similar among forest types, the transmission of water to the forest floor per basal area unit was significantly higher in native forests. Yet, nutrient concentrations were similar among them. However, greater nutrient enrichment per unit basal area was observed for the native species. This more efficient nutrient cycling could be related to native forests being better adapted to oligotrophic soils. The re-establishment of native species rather than with exotic species can result in more efficient hydrochemical regulation, improving the capacity of these ecosystems to produce services.

We introduce Dynamic Constrained Grid (DCGrid), a hierarchical and adaptive grid structure for fluid simulation combined with a scheme for effectively managing the grid adaptations. DCGrid is designed to be implemented on the GPU and used in high-performance simulations. Specifically, it allows us to efficiently vary and adjust the grid resolution across the spatial domain and to rapidly evaluate local stencils and individual cells in a GPU implementation. A special feature of DCGrid is that the control of the grid adaption is modeled as an optimization under a constraint on the maximum available memory, which addresses the memory limitations in GPU-based simulation. To further advance the use of DCGrid in high-performance simulations, we complement DCGrid with an efficient scheme for approximating collisions between fluids and static solids on cells with different resolutions. We demonstrate the effectiveness of DCGrid for smoke flows and complex cloud simulations in which terrain-atmosphere interaction requires working with cells of varying resolution and rapidly changing conditions. Finally, we compare the performance of DCGrid to that of alternative adaptive grid structures.

Due to the complex interplay of various meteorological phenomena, simulating weather is a challenging and open research problem. In this contribution, we propose a novel physics-based model that enables simulating weather at interactive rates. By considering atmosphere and pedosphere we can define the hydrologic cycle - and consequently weather - in unprecedented detail. Specifically, our model captures different warm and cold clouds, such as mammatus, hole-punch, multi-layer, and cumulonimbus clouds as well as their dynamic transitions. We also model different precipitation types, such as rain, snow, and graupel by introducing a comprehensive microphysics scheme. The Wegener-Bergeron-Findeisen process is incorporated into our Kessler-type microphysics formulation covering ice crystal growth occurring in mixed-phase clouds. Moreover, we model the water run-off from the ground surface, the infiltration into the soil, and its subsequent evaporation back to the atmosphere. We account for daily temperature changes, as well as heat transfer between pedosphere and atmosphere leading to a complex feedback loop. Our framework enables us to interactively explore various complex weather phenomena. Our results are assessed visually and validated by simulating weatherscapes for various setups covering different precipitation events and environments, by showcasing the hydrologic cycle, and by reproducing common effects such as Foehn winds. We also provide quantitative evaluations creating high-precipitation cumulonimbus clouds by prescribing atmospheric conditions based on infrared satellite observations. With our model we can generate dynamic 3D scenes of weatherscapes with high visual fidelity and even nowcast real weather conditions as simulations by streaming weather data into our framework.

Objectives. Congenital cytomegalovirus infection (cCMV) has been considered more prevalent among HIV-exposed children during pregnancy. Spanish national guidelines recommend the cCMV screening in these newborns. Nowadays, pregnant women have a better control of HIV infection compared to previous decades. We aim to analyze the prevalence and associated risk factors to cCMV in these children. Patients and methods. A retrospective cross-sectorial study was performed. All newborns exposed to HIV were assisted in a third-level hospital (2014-2020). Epidemiological and clinical data of the mother and newborn were recorded. Shell vial urine culture and/or CRP were performed along the two first weeks of life for the neonatal screening of cCMV. Results. Overall 69 newborns were enrolled. A high proportion (82.4%) of the mothers had been diagnosed with HIV before getting pregnant. All women received ART during the pregnancy. Median T-CD4 lymphocytes before delivery was 641/mm3 (IQR: 480-865) and the viral load was undetectable in 83.6%. Serological test for CMV along the first trimester of pregnancy was performed in 73.5% (positive IgG in 96%). There were no congenital cases of HIV neither cCMV (CI 95%:0-5.3%). Conclusions. The cCMV prevalence in newborns exposed to HIV was 0%, lower than reported before, probably related to a better and earlier ART during pregnancy, leading to a better immunological status.

Congenital Zika infection has been linked with a characteristic phenotype including neurologic sequelae. However, West syndrome has not been previously well described as a consequence. We aim to show this association through a retrospective descriptive study performed in Ecuador. Among 147 infants with congenital Zika infection, 7.5% suffered from West syndrome. Vigabatrin seems to be effective to control the spasms.

Rainfall mechanisms in the Central American Isthmus are controlled by complex physical interactions across spatial and temporal scales, which are reflected on the dynamics of atmospheric circulation patterns affecting the region. However, physical mechanisms and their relationships with thermodynamic distributions connected to overturning circulations remain elusive. Here, a set of six recurrent daily atmospheric patterns, or weather types (WT), is defined using a k-means++ clustering algorithm on standardized fields of Convective Available Potential Energy (CAPE) and winds at 925, 850, and 200 hPa. The relationships between these weather types, their temporal characteristics, and anomalous distributions of moisture flux divergence, equivalent potential temperature (saturated and unsaturated), and observed rainfall are used to describe physical processes controlling the latter, for all seasons. Regional observed rainfall is analysed from a set of 174 automatic stations from all countries from Mexico to Panama. By modulating vertically integrated moisture fluxes, these weather types, and the different climate drivers linked to them, control the temporal and spatial rainfall characteristics in the region, especially over the Pacific side of the isthmus. During some stages of the regional rainy season, described by two weather types, thermal anomalies in convective quasiequilibrium characteristic of the upward branch of the Hadley cell force westerly flow over Central America, enhancing rainfall. While during other stages, the enhancement of the trades and the displacement of convection to the ITCZ area over the eastern tropical Pacific, characteristic of the midsummer drought, diminishes rainfall. This study sets the stage for a better understanding of the mechanistic relationship between these weather types and rainfall characteristics in general, like onset, demise, and duration of rainy seasons. Hence, these results can inform process-based model diagnostics aiming at bias-correcting climate predictions at multiple timescales Universidad de Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI) UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Física UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR)

La construcción de las sociedades actuales ha sido posible gracias a los aportes de numerosos personajes a la política, a la economía, a las artes y a las ciencias. Considerado uno de los actores del proceso de independencia de Costa Rica, el bachiller Rafael Francisco Osejo tuvo una prolífica vida como político, educador y abogado; sin embargo, es relativamente poco lo que se conoce sobre su aporte al desarrollo de la ciencia de su época. Aquí se analizan sus escritos al tenor de la ciencia del periodo para responder a la pregunta: ¿fue Osejo un hombre de ciencia de su época? Se examinan y discuten sus dos principales obras relacionadas con temas como sismología, astronomía, matemática, física y meteorología, investigando, como complemento, los contenidos de algunas de las obras que este personaje tenía en su biblioteca. Osejo fue un personaje muy bien informado y educado en el conocimiento científico de su época. Logró, como hombre de ciencia, una activa participación personal e institucional en el inicio de una relevante época científica en el país. The construction of today's societies has been possible thanks to the contributions of numerous characters to politics, economics, the arts, and sciences. Considered one of the actors in the process of independence of Costa Rica, the Bachelor Rafael Francisco Osejo had a prolific life as a politician, educator, and lawyer, however, there is relatively little that is known about his contribution to the development of a science of his time. Here his writings are analyzed in the tenor of the science of the period to answer the question: Was Osejo a man of science of his time? His two main works related to topics such as seismology, astronomy, mathematics, physics, and meteorology are examined and discussed, investigating as a complement to the contents of some of the works that this character had in his library. Osejo was a very well-informed and educated character in the scientific knowledge of his time. As a man of science, he achieved an active personal and institutional participation at the beginning of a relevant scientific era in the country. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI)

Existen fuertes críticas a la baja relación que existe entre los procesos de investigación y el contexto empresarial en las facultades, los programas de administración y las escuelas de negocios poco posicionados. Este documento tiene como objetivo determinar los temas relevantes en ciencias administrativas mediante la aplicación de análisis de redes para identificar las instituciones que manejan temas recurrentes, aquellas que abordan temas especializados y los territorios con investigación en el campo administrativo. Se identificaron las mejores facultades, programas de administración y escuelas de negocios a nivel mundial y nacional y a partir de esta selección, se construyó un modelo relacional de las interacciones entre las instituciones y las temáticas utilizando la teoría de redes. Se implementó este tipo de análisis dadoque permite la revisión sistemática y sus resultados se convierten en insumos que contribuyen a la posterior toma de decisiones por parte de las instituciones inmersas en este campo. Entre los resultados se encuentran como nodos institucionales notables la Escuela de Negocios de Columbia, la Escuela de Negocios Insead, la Universidad de Negocios Cornell, la Escuela de Negocios de Harvard y, finalmente, la Escuela de Gestión SLOAN del Massachusetts Institute of Technology. Finalmente, se identificaron como nodos temáticos relevantes aquellos relacionados con finanzas, emprendimiento, globalización y liderazgo.

Background Few congenital Zika syndrome (CZS) cases have been notified in Ecuador and, to our knowledge, there are no significant published studies dealing with their clinical evolution. We present a detailed clinical characterization of 21 children with congenital Zika virus (ZIKV) infection born in Ecuador who were followed up until September 2019. Methods We did a retrospective longitudinal study of children attended by the infectious disease specialists of Francisco Icaza Bustamante Children’s Hospital (Guayaquil) due to congenital ZIKV infection suspicion. The inclusion criteria consisted of laboratory confirmed diagnosis of congenital ZIKV infection. Results Sixteen of these 21 cases of congenital ZIKV infection showed clinical, neuroimaging and laboratory findings strongly suggestive of CZS and 5 children showed laboratory findings compatible with congenital ZIKV infection without congenital manifestations associated to CZS. All children with CZS showed neurodevelopmental delay, spasticity and hyperreflexia during follow-up, whereas the majority of them (14/15) experienced recurrent epileptic seizures and dysphagia (12/13). Two CZS cases died during follow-up. Visual evoked potential and hearing screening with acoustically evoked auditory brainstem response were abnormal in 50% and 37.5% of CZS cases, respectively. Congenital ZIKV infection without findings consistent with CZS at birth was not clinically relevant at 23 months of age in the five cases of our cohort. Conclusions Severe neurodevelopmental delay, severe microcephaly, epileptic seizures and dysphagia were present at 2 years of age in most CZS cases of our cohort.

An improved understanding of ecosystem functions is increasingly needed as ecosystem management moves towards optimizing their capacity to provide services to society. Such a task requires the characterization of ecosystem functions in strategic systems such as tropical mountain forests, which are also subject to pressure due to both global and local environmental changes. In particular, transformation of native forests into pastures or agriculture, has been regarded as the type of transformation with the largest effects in ecosystem regulating and provision functions. However, the effects of other transformations such as those associated with replacement of native with planted forests, have been less studied. To evaluate the effect of forest type on key-ecosystem functions related to water resources, we studied the dynamics of rainfall partitioning and nutrient circulation on a suite of representative forest types in neotropical mountain systems: two plantations of exotic fast-growing species and two types of native forests. Our results illustrate that, when considered in a per-basal unit area, water transmission to the forest floor is significantly higher in both native forests. Similarly, native forests are more effective on circulating nutrients on the ecosystem as they are better adapted to oligotrophic soils such as those occurring in tropical mountains. These results suggest that the replacement of native forests with exotic tree plantations can potentially impact hydrological regulation and the nutrient cycling in these high Andean lands, affecting both directly and indirectly the capacity of ecosystems to produce services to society.

A theoretical study of the effect of the substituent Z on the gas phase acidity of substituted benzoic acids ZC6H4COOH in terms of density functional theory descriptors (chemical potential, softness and Fukui function) is presented. The calculated gas phase &Delta, acidG&deg, values obtained were close to the experimental ones reported in the literature. The good relationship between the &Delta, values and the electronegativity of ZC6H4COOH and its fragments, suggested a better importance of the inductive than polarizability contributions. The balance of inductive and resonance contributions of the substituent in the acidity of substituted benzoic acids showed that the highest inductive and resonance effects were for the -SO2CF3 and -NH2 substituents in the para- and ortho-position, respectively. The Fukui function confirmed that the electron-releasing substituent attached to the phenyl ring of benzoic acid decreased the acidity in the trend ortho &gt, meta &gt, para, and the electron-withdrawing substituent increased the acidity in the trend ortho &lt, meta &lt, para.

Lightning activity has been recognized to have, historically, social and environmental consequences around the globe. This work analyzes the space-time distribution of lightning-densities (D) in an extended Central America region (ECA). World Wide Lightning Location Network data was analyzed to link D with dominant climate patterns over the ECA for 2012–2020. D associated with cold surges entering the tropics dominate during boreal winter. The highest D (hot-spots) was found to agree well with previously known sites, such as the “Catatumbo” in Venezuela; however, D was lower here due to different detection efficiencies. Previously reported hot-spots showed strong continental signals in CA; however, in this work, they were over the oceans near to coastlines, especially in the eastern tropical Pacific (ETP). Most cold-spots, implying a minimum of vulnerability to human impacts and to some industries, were situated in the Caribbean Sea side of Central America. The Mid-Summer-Drought and the Caribbean-Low-Level-Jet (CLLJ) markedly reduced the D during July-August. The CLLJ in the central CS and across the Yucatan and the southern Gulf of Mexico acts as a lid inhibiting convection due to its strong vertical shear during the boreal summer. The CLLJ vertical wind-shear and its extension to the Gulf of Papagayo also diminished convection and considerably decreased the D over a region extending westward into the ETP for at least 400–450 km. A simple physical mechanism to account for the coupling between the CLLJ, the MSD, and lightning activity is proposed for the latter region. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI)

Context: The complexity in critical patient management and polypharmacy, raise the need for support from a clinical pharmacist to optimize drug therapies. Aims: To evaluate the clinical pharmacist participation in an Adult Intensive Care Unit in a local context where the practice is not well established. Methods: The study was conducted in a teaching hospital. Consisted of two stages a retrospective in which were collected of pharmacotherapy follow-up during a period of two years and a prospective phase of observational and cross-sectional character, which picked up the clinical history of patients and pharmaceutical interventions. These pharmaceutical interventions were evaluated by two intensive care physicians and two external pharmacist, using a default score to each one of these, the degree of concordance was obtained using the kappa coefficient. Results: In the retrospective phase were collected 182 patients, who were performed a total of 750 interventions, of which 99.7% was accepted by physician. In the prospective phase, were analyzed 53 patients that involved 263 pharmaceutical interventions with 96.6% of acceptance on the part of the medical staff. The degree of correlation of the interventions was κ = 0.61 between two physicians of the unit, and κ = 0.71 between two external pharmacists. Conclusions: The contribution that a clinical pharmacist can provide in an adult intensive care has a positive impact on the treatment of patients with a high percentage of acceptances on the part of the medical team.

Resumen Las exacerbaciones pulmonares de causa infecciosa son una de las mayores complicaciones en los pacientes con fibrosis quística (FQ). Estas se asocian a un progresivo aumento en la morbilidad y mortalidad. El tratamiento antimicrobiano se realiza dependiendo del microorganismo aislado. Con frecuencia se utilizan antimicrobianos β-lactámicos, los cuales no están exentos de reacciones adversas. A continuación, se describen dos casos de neutropenia tras el uso prolongado de cefepime en pacientes con FQ.

The Caribbean low‐level jet (CLLJ) is an important modulator of regional climate, especially precipitation, in the Caribbean and Central America. Previous work has inferred, due to their semiannual cycle, an association between CLLJ strength and meridional sea surface temperature (SST) gradients in the Caribbean Sea, suggesting that the SST gradients may control the intensity and vertical shear of the CLLJ. In addition, both the horizontal and vertical structure of the jet have been related to topographic effects via interaction with the mountains in Northern South America (NSA), including funneling effects and changes in the meridional geopotential gradient. Here we test these hypotheses, using an atmospheric general circulation model to perform a set of sensitivity experiments to examine the impact of both SST gradients and topography on the CLLJ. In one sensitivity experiment, we remove the meridional SST gradient over the Caribbean Sea and in the other, we flatten the mountains over NSA. Our results show that the SST gradient and topography have little or no impact on the jet intensity, vertical, and horizontal wind shears, contrary to previous works. However, our findings do not discount a possible one‐way coupling between the SST and the wind over the Caribbean Sea through friction force. We also examined an alternative approach based on barotropic instability to understand the CLLJ intensity, vertical, and horizontal wind shears. Our results show that the current hypothesis about the CLLJ must be reviewed in order to fully understand the atmospheric dynamics governing the Caribbean region. Consejo Superior Universitario Centroamericano/[805-A9-532]/CSUCA/Guatemala Agencia Sueca de Desarrollo Internacional/[805-A9-532]/ASDI/Suecia Universidad de Costa Rica/[805-B6-143]/UCR/Costa Rica Consejo Nacional para Investigaciones Científicas y Tecnológicas/[805-B6-143]/CONICIT/Costa Rica Ministerio de Ciencia, Tecnología y Telecomunicaciones/[805-B6-143]/MICITT/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI) UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Física

Context: Critically ill patients has a large number of pathophysiological changes product of commitment and organ systems. Therefore, knowledge of the pharmacological properties of antimicrobials is essential to choose the best treatment. In order to optimize the response of antibiotic therapy and these drugs, new strategies have been proposed dosage, the most used drug application of the model, called: Pharmacokinetics/Pharmacodynamics (PK/PD). In the case of β-lactam antibiotics, the PK/PD model is known as time-dependent on the Minimum Inhibitory Concentration (Time > MIC). For optimal concentrations in β-lactam antibiotics, prolonged or continuous infusions, thus exposing the drug on the pathogen is achieved in a longer optimal concentrations through are used. Aims: To evaluate the therapeutic response of β-lactam antibiotics in critically ill patients with prolonged infusions by applying the model PK/ PD. Methods: Prospective observational study (concurrent cohort), taking as a control non-concurrent historic cohort, conducted for a period of seven months in the intensive care unit of the Hospital Clínico San Borja Arriarán (HCSBA), Santiago, Chile. Results: It was found a significant difference in number of days of hospitalization in ICU for the group bolus versus infusion group (12.5 ± 5.4 vs. 18 ± 9.7 days, IC: 1.5-9.5; p = 0.009). Conclusions: This study suggests that there would be a therapeutic advantage in the use of prolonged infusion in ICU stay duration.

De acuerdo a referencias, existe una fuerte influencia del estrés con el desarrollo de enfermedades. En este trabajo se consideraron los atributos que hacen posible esa influencia para la elaboración de un modelo matemático que permite el planteamiento de escenarios que cambian con la frecuencia con la que un individuo implementa soluciones temporales para atender el estrés (pseudosoluciones) o cambia la frecuencia con la que recibe el tratamiento médico especializado para atender la enfermedad. Los resultados son concluyentes de la dinámica del comportamiento del sistema, permitiendo la configuración de escenarios en los que es posible que el paciente: 1) sane completamente, 2) alcance niveles estables de estrésenfermedad que puede sobrellevar sin riesgos pero con la implementación de diferentes pseudosoluciones y tratamientos médicos, o 3) ponga en riesgo su vida.

We explored the relationship between the precipitation anomalies during May to June as the first peak of the rainy season in the Pacific slope of Central America, and sea surface temperature (SST) fluctuations in the surrounding oceans, using canonical correlation analysis (CCA). With this approach, we studied variations in total precipitation, frequency of rainy days and the monthly occurrence of days with rainfall above (below) the 80th (20th) percentile, due to changes in the nearby SST. Composites of the sea-level pressure (SLP), geopotential heights (200 hPa), relative humidity (700 hPa), horizontal moisture flux and wind at 850 hPa were estimated to provide a dynamical analysis. The composites are calculated using the information obtained with CCA. In addition, we used a general circulation model forced with fixed SST to explore the sensitivity of the model to the SST patterns found using CCA. The results show that the SST over the tropical North Atlantic controls the precipitation fluctuations at interannual scales, due to its connection with the tropical upper tropospheric trough. Warmer (colder) temperatures result in SLP below normal in the Caribbean region, associated with an increase in the heights at 200 hPa. This vertical configuration reduces the wind shear between 850 and 200 hPa and increases the input of humidity to mid-levels, creating favourable conditions for deep convection, and favouring the generation of tropical cyclone activity. In the Pacific, a positive anomalous low-level moisture flux is observed from the ocean to the continental parts of the region and may enhance the formation of mesoscale systems. The classic prediction schemes show a lead time of 1 or 2 months; this is an advantage for climate services operative work. The atmospheric model outcomes replicate the main results found in the composite analysis, reflecting its potential use for model output statistics predictive schemes.

Although the hydric stress in Central America is generally low, there is a region relatively drier and prone to drought known as the Central America Dry Corridor (CADC). The area of interest is located mainly in the Pacific slope of Central America, from Chiapas in southern Mexico, to the Nicoya Peninsula in the Costa Rican North Pacific. Most of the region has experienced significant warming trends (1970–1999). On the contrary precipitation and the Palmer Drought Severity Index (PDSI) have mainly displayed non-significant trends. Analysis using the Standardized Precipitation Index and PDSI in the CADC, suggests a significant periodicity of severe and sustained droughts of around 10 years. The drought response has been associated with tropical heating that drives an atmospheric response through strengthening of the Hadley cell, which in turn produces higher pressure in the subtropical highs, and intensification of the trade winds (indexed by the Caribbean Low Level Jet). It is important to determine the commonness of severe and sustained droughts in the CADC to improve water resources planning, as this is a region that depends on subsistence agriculture and presents high social and economic vulnerabilities. Universidad de Costa Rica/[805-B7-286]/UCR/Costa Rica Universidad de Costa Rica/[805-B7-507]/UCR/Costa Rica Universidad de Costa Rica/[805-B6-143]/UCR/Costa Rica Universidad de Costa Rica/[805-A9-532 ]/UCR/Costa Rica Universidad de Costa Rica/[805-B4-227]/UCR/Costa Rica Universidad de Costa Rica/[805-B0-065]/UCR/Costa Rica Universidad de Costa Rica/[805-B4-227]/UCR/Costa Rica Universidad de Costa Rica/[805-B0-810]/UCR/Costa Rica Universidad de Costa Rica/[805-B8-766]/UCR/Costa Rica Universidad de Costa Rica/[805-B9-454 ]/UCR/Costa Rica Universidad de Costa Rica/[805-A4-906]/UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI) UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Física UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR)

Historical civilizations have evidenced different routes to the collapse mainly due to political, warfare, cultural and environmental damages. This has animated modern researches to study and understand social, economic, and environmental challenges that modern societies must adopt in order to avoid history from repeat itself, and even worst, irreversibly. Many of these researches are focused on modelling through sets of ordinary differential equations (ODE's) representing the dynamic interaction between natural resources and population in an isolated society. In this work, we introduce the fact of cooperation between two similar societies, modelled as sets of ODE's of the type Brander and Taylor (1998), in the sense that economical exchange can exist between them. We couple two societies by introducing a simple receive-and-protect rule in which one society receive the other's help under the condition of protecting its own resources. We set that this cooperation may be constant, when it does not change all over the time, or changes intermittently depending on the level of resources each society has at any time. When cooperation is constant, the resulting system is a 4-dimensional system of ODE's that evolves smoothly, but if cooperation is intermittent, the coupled 4-dimensional system becomes a Filippov system. In both cases, we found that under economic cooperation, societies can survive at least in the long run, different from what happens when both societies are treated in isolation for the same parameter values.

The local and condensed Fukui functions as well as the principle of hard and soft acids and bases were used to study the addition of free radicals to the exocyclic and endocyclic double bonds of seven monocyclic monoterpenes of formula C10H16. The results obtained showed that, in general, the most reactive double bond was the one with the most substituents on the double-bonded carbon atoms, and that the reaction of a double bond with an electrophile is a soft-soft interaction. The effects of substituents on the double-bonded carbon atoms and the stabilization of the monoterpenes were interpreted by invoking hyperconjugated structures, which led us to propose a simple rule: the larger the value of the Fukui function for the double bond, the greater the hyperconjugative stabilization and the susceptibility of the double bond to electrophilic attack. In general, our results are in good accordance with relevant experimental and theoretical results published in the literature. Graphical abstract The specific electrophilic addition to monocyclic monoterpenes.

Using the regional climate model WRF, and the NCEP-NCAR Reanalysis Project data as boundary and initial conditions, regional precipitation for Central America was estimated by means of the dynamical downscaling technique for two selected periods: January 2000 and September 2007. Four-nested domains, d01, d02, d03 and d04 with a grid-resolution of 90 km, 30 km, 10 km, and 3.3 km respectively, were configured over this region. The runs were reinitialized every 5 days with 6 h of spin-up time for adjustment of the model. A total of eight experiments (four per month) were tested in order to study: a) two important Cumulus Parameterization Schemes (CPS): Kain-Fritsch (KF) and Grell-Devenyi (GD); and b) the physical interaction between nested domains (one- and two-way nesting), during each simulated month. The modeled precipitation was in agreement with observations for January 2000, and also captured the mean climate features of rainfall concerning magnitude, and spatial distribution, such as the particular precipitation contrast between the Pacific and the Caribbean coast. Outputs of the coarse domains (d01, d02, and d03) for September 2007 revealed differences between experiments within the domains when a visual comparison of the spatial distribution was made. However, for the inner grid (d04), all the experiments, showed a similar spatial distribution and magnitude estimation, mainly in those runs using one-way nesting configuration. The results for the month of September differed substantially with the observations, which could be related to associated deficiencies in the boundary condition that do not reproduce well the transition periods from warm to cold ENSO episodes for the selected periods of study. In all the experiments, the KF scheme calculated more precipitation than the GD scheme and it was associated to the ability of the GD scheme to reproduce spotty but intense rainfall, and apparently, this scheme was reluctant to activate, showing frequent events of low intensity rain. However, when rainfall did develop, it was very intense. Also, the time series did not replicate specific precipitation events. Thus, the 5-days integration period used in this study was not enough to reproduce short-period precipitation events. Finally, physical interaction issues between the nested domains were reflected in discontinuities in the precipitation field, which have been associated with mass field adjustment in the CPS. Rev. Biol. Trop. 66(Suppl. 1): S231-S254. Epub 2018 April 01. Utilizando el modelo climático regional WRF y los datos del Proyecto de Reanálisis del NCEP-NCAR como condiciones iniciales y de frontera, se estimó la precipitación regional para Centroamérica mediante la técnica de reducción dinámica para dos períodos seleccionados, enero de 2000 y septiembre de 2007. Cuatro dominios anidados se configuraron en esta región, d01, d02, d03 y d04 con resoluciones de 90 km, 30 km, 10 km y 3.3 km respectivamente. Las simulaciones se reinicializaron cada 5 días con 6 horas de tiempo de ajuste del modelo. Un total de 8 experimentos (4 por mes) fueron probados con el fin de estudiar: a) dos importantes Esquemas de Parametrización de Cumulus: Kain-Fritsch (KF) y Grell-Devenyi (GD); y b) la interacción física entre dominios anidados (respuesta de un y doble sentido), durante cada mes simulado. En enero de 2000 los resultados mostraron que la precipitación modelada está de acuerdo con las observaciones y también capturó las características climáticas de la precipitación respecto a la magnitud y la distribución espacial, como el contraste de precipitación particular entre la costa del Pacífico y el Caribe. Los resultados de septiembre de 2007 revelaron diferencias significativas cuando se hace una comparación visual con la distribución espacial de cada dominio grueso (d01, d02 y d03) con su dominio respectivo en cada experimento. Sin embargo, los dominios d04 de todos los experimentos mostraron una distribución espacial y una estimación de magnitud similares, principalmente en aquellas series que usan una configuración de anidamiento unidireccional. Por otra parte, los resultados de este mes difieren sustancialmente con las observaciones, y este último podría estar relacionado con deficiencias asociadas en la condición de frontera que no reproducen bien los períodos de transición de los episodios de cálido a frío del ENOS. Además, en todos los experimentos, el esquema KF calculó más precipitación que el esquema GD y está asociado a la capacidad del esquema GD para reproducir lluvias irregulares pero intensas, y aparentemente este esquema es reacio a activarse, produciendo lluvia con poca frecuencia o ninguna. Sin embargo, cuando la lluvia se desarrolla, es muy intensa. Además, las series de tiempo no replican eventos de precipitación específicos, por lo tanto, el período de integración de 5 días usado en este estudio, no es suficiente para reproducir eventos de precipitación a corto plazo. Por último, los problemas de interacción física entre los dominios anidados se reflejan en las discontinuidades en el campo de precipitación, que se han asociado con el ajuste del campo de masa en el CPS. Swedish International Development Cooperation Agency/[54100006]/SIDA/Suecia Uppsala University/[54100006]//Suecia Universidad de Costa Rica/[805-B7-507]/UCR/Costa Rica Universidad de Costa Rica/[805-B6-143]/UCR/Costa Rica Universidad de Costa Rica/[805-B4-227]/UCR/Costa Rica Universidad de Costa Rica/[805-B0-065]/UCR/Costa Rica Universidad de Costa Rica/[805-A9-532]/UCR/Costa Rica Universidad de Costa Rica/[850-B7-286]/UCR/Costa Rica Universidad de Costa Rica/[805-B7-286]/UCR/Costa Rica Universidad de Costa Rica/[805-B0-810]/UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI) UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR)

"SECOND WORKSHOP ON CLIMATE CHANGE, VARIABILITY AND MODELING OVER CENTRAL AMERICA AND MEXICO What: International experts and attendees from several countries of Central America, Mexico, the Caribbean (CAM), and South America (SA) met to discuss regional issues on climate variability and climate change to learn the use of the non-hydrostatic version of the International Center for Theoretical Physics (ICTP) RegCM4.6 model, and to establish a regional modeling scientific community for understanding the physics of climate processes and the generation of regional climate change scenarios.When:14-18 November 2016.Where:Center for Geophysical Research (CIGEFI in Spanish) and School of Physics, University of Costa Rica (UCR), San José, Costa Rica."