Políticas de cambio climático en Costa Rica, integrando esfuerzos para asumir los retos

Ante el fenómeno de cambio climático, que muchos consideran el mayor reto que la humanidad ha enfrentado, las políticas públicas son cruciales. Con el fin de establecer la capacidad de Costa Rica para alcanzar los objetivos de la Estrategia Nacional de Cambio Climático, se efectúa un análisis de las políticas públicas nacionales. Se hace una ubicación general de la normativa e iniciativas internacionales para abordar el fenómeno de cambio climático, destacando la falta de concreción de instrumentos efectivos para atacar este problema. Por otra parte, se define y describe el fenómeno climático y el calentamiento global que lleva al cambio climático

Experimental approach for the uncertainty assessment of 3D complex geometry dimensional measurements using computed tomography at the mm and sub-mm scales

The dimensional verification of miniaturized components with 3D complex geometries is particularly challenging. Computed Tomography (CT) can represent a suitable alternative solution to micro metrology tools based on optical and tactile techniques. However, the establishment of CT systems’ traceability when measuring 3D complex geometries is still an open issue. In this work, an alternative method for the measurement uncertainty assessment of 3D complex geometries by using CT is presented. The method is based on the micro-CT system Maximum Permissible Error (MPE) estimation, determined experimentally by using several calibrated reference artefacts. The main advantage of the presented method is that a previous calibration of the component by a more accurate Coordinate Measuring System (CMS) is not needed. In fact, such CMS would still hold all the typical limitations of optical and tactile techniques, particularly when measuring miniaturized components with complex 3D geometries and their inability to measure inner parts. To validate the presented method, the most accepted standard currently available for CT sensors, the Verein Deutscher Ingenieure/Verband Deutscher Elektrotechniker (VDI/VDE) guideline 2630-2.1 is applied. Considering the high number of influence factors in CT and their impact on the measuring result, two different techniques for surface extraction are also considered to obtain a realistic determination of the influence of data processing on uncertainty. The uncertainty assessment of a workpiece used for micro mechanical material testing is firstly used to confirm the method, due to its feasible calibration by an optical CMS. Secondly, the measurement of a miniaturized dental file with 3D complex geometry is carried out. The estimated uncertainties are eventually compared with the component’s calibration and the micro manufacturing tolerances to demonstrate the suitability of the presented CT calibration procedure. The 2U/T ratios resulting from the validation workpiece are, respectively, 0.27 (VDI) and 0.35 (MPE), by assuring tolerances in the range of +- 20–30 micro-m. For the dental file, the EN < 1 value analysis is favorable in the majority of the cases (70.4%) and 2U/T is equal to 0.31 for sub-mm measurands (L < 1 mm and tolerance intervals of +- 40–80 micro-m)

Functionalized Nanostructures with Application in Regenerative Medicine

In the last decade, both regenerative medicine and nanotechnology have been broadly developed leading important advances in biomedical research as well as in clinical practice. The manipulation on the molecular level and the use of several functionalized nanoscaled materials has application in various fields of regenerative medicine including tissue engineering, cell therapy, diagnosis and drug and gene delivery. The themes covered in this review include nanoparticle systems for tracking transplanted stem cells, self-assembling peptides, nanoparticles for gene delivery into stem cells and biomimetic scaffolds useful for 2D and 3D tissue cell cultures, transplantation and clinical application

Modelling the Dynamics of an Aedes albopictus Population

We present a methodology for modelling population dynamics with formal means of computer science. This allows unambiguous description of systems and application of analysis tools such as simulators and model checkers. In particular, the dynamics of a population of Aedes albopictus (a species of mosquito) and its modelling with the Stochastic Calculus of Looping Sequences (Stochastic CLS) are considered. The use of Stochastic CLS to model population dynamics requires an extension which allows environmental events (such as changes in the temperature and rainfalls) to be taken into account. A simulator for the constructed model is developed via translation into the specification language Maude, and used to compare the dynamics obtained from the model with real data.Comment: In Proceedings AMCA-POP 2010, arXiv:1008.314

Phosphomannosylation and the functional analysis of the extended Candida albicans MNN4-like gene family

We thank Luz A. López-Ramírez (Universidad de Guanajuato) for technical assistance. This work was supported by Consejo Nacional de Ciencia y Tecnología (ref. CB2011/166860; PDCPN2014-247109, and FC 2015-02-834), Universidad de Guanajuato (ref. 000025/11; 0087/13; ref. 1025/2016; Convocatoria Institucional para Fortalecer la Excelencia Académica 2015; CIFOREA 89/2016), Programa de Mejoramiento de Profesorado (ref. UGTO-PTC-261), and Red Temática Glicociencia en Salud (CONACYT-México). NG acknowledges the Wellcome Trust (086827, 075470, 101873, and 200208) and MRC Centre for Medical Mycology for funding (N006364/1). KJ was supported by a research visitor grant to Aberdeen from China Scholarship Council (CSC No. 201406055024). The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fmicb.2017.02156/full#supplementary-materialPeer reviewedPublisher PD

Social, clinical, and policy implications of ultra-processed food addiction

Key messages Ultra-processed foods high in refined carbohydrates and added fats are highly rewarding, appealing, and consumed compulsively and may be addictive Behaviours around ultra-processed food may meet the criteria for diagnosis of substance use disorder in some people •   Ultra-processed food addiction is estimated to occur in 14% of adults and 12% of children and is associated with biopsychological mechanisms of addiction and clinically significant problems Understanding of these foods as addictive could lead to novel approaches in the realm of social justice, clinical care, and policy approache

Thermal effects in Ni/Au and Mo/Au gate metallization AlGaN/GaN HEMT's reliability

AlGaN/GaN high electron mobility transistors (HEMT) are key devices for the next generation of high-power, high-frequency and high-temperature electronics applications. Although significant progress has been recently achieved [1], stability and reliability are still some of the main issues under investigation, particularly at high temperatures [2-3]. Taking into account that the gate contact metallization is one of the weakest points in AlGaN/GaN HEMTs, the reliability of Ni, Mo, Pt and refractory metal gates is crucial [4-6]. This work has been focused on the thermal stress and reliability assessment of AlGaN/GaN HEMTs. After an unbiased storage at 350 o C for 2000 hours, devices with Ni/Au gates exhibited detrimental IDS-VDS degradation in pulsed mode. In contrast, devices with Mo/Au gates showed no degradation after similar storage conditions. Further capacitance-voltage characterization as a function of temperature and frequency revealed two distinct trap-related effects in both kinds of devices. At low frequency (< 1MHz), increased capacitance near the threshold voltage was present at high temperatures and more pronounced for the Ni/Au gate HEMT and as the frequency is lower. Such an anomalous “bump” has been previously related to H-related surface polar charges [7]. This anomalous behavior in the C-V characteristics was also observed in Mo/Au gate HEMTs after 1000 h at a calculated channel temperatures of around from 250 o C (T2) up to 320 ºC (T4), under a DC bias (VDS= 25 V, IDS= 420 mA/mm) (DC-life test). The devices showed a higher “bump” as the channel temperature is higher (Fig. 1). At 1 MHz, the higher C-V curve slope of the Ni/Au gated HEMTs indicated higher trap density than Mo/Au metallization (Fig. 2). These results highlight that temperature is an acceleration factor in the device degradation, in good agreement with [3]. Interface state density analysis is being performed in order to estimate the trap density and activation energy

CARACTERIZACIÓN DE LA POBLACIÓN DE Dasypus novemcinctus Y FAUNA ASOCIADA A SUS MADRIGUERAS EN SONÁ, VERAGUAS, PANAMÁ

La evaluación de las poblaciones de armadillos en zonas perturbadas por asentamientos y ganadería, reciben poca importancia, lo que afecta el estado de conservación de la especie. En nuestro país no existen estudios sobre densidad poblacional, patrones de uso de madrigueras y comportamiento general en armadillos. Por ello, el presente estudio tuvo como objetivo caracterizar la población de armadillos Dasypus novemcinctus e inventariar las especies de vertebrados asociados a sus madrigueras, en una finca dedicada a la ganadería intensiva, en Soná, Veraguas, Panamá. Para la realización de esta investigación, se utilizó un método mixto de observación directa y cámaras trampa desde enero hasta junio de 2022. Se detectaron 47 armadillos y se determinó una densidad de 1.25 madrigueras/a y 0.38 ind/ha. Se registraron un total de 18 especies asociadas a las madrigueras de D. novemcinctus; nueve de aves, siete de mamíferos y dos de reptiles. Se presentan las primeras observaciones de Tamandúa mexicana, Procyon lotor y Conepatus semistriatus, los cuales no habían sido reportados en esta localidad. El presente estudio resalta la importancia de los armadillos como especie clave en ecosistemas, ya que por su actividad atraen múltiples especies, contribuyendo a mantener la biodiversidad; incluso en zonas intervenidas como fincas ganaderas

Effects of N2 Plasma Pretreatment on the SiN Passivation of AlGaN/GaN HEMT

The impact of in situ low-power plasma pretreatment, prior to silicon-nitride (SiN) deposition, was investigated in AlGaN/GaN high-electron mobility transistors (HEMTs). These studies reveal that the use of plasma in HEMT passivation reduces current-collapse and gate-lag effects. Such treatment is also beneficial to improve gate leakage, and from RF measurements, no degradation of was observed. These beneficial effects of the plasma pretreatment seem to be due to a significant reduction in interface charge density, as shown in this letter using GaN MIS devices, where a decrease of 60% was observed

La dimensión ética del desarrollo local

The nowadays conceptions about the community development, have a certain technocratic focus when conceiving just the economic, scientific, technic and environmental dimension bound to the knowledge management. This criteria doesn't recognize the central role that means the moral athics dimension in the social life. The aim of this research is to perform a critic analisis of the problem itself as it is showed in the nowadays Cuban society, beginning with Marti's and Marx's conception of the cultural development in the Cuban Revolution.Las concepciones actuales sobre el desarrollo local tienen cierto enfoque tecnocrático al concebir solo la dimensión económica, ecológica y científica tecnológica vinculada a la gestión del conocimiento. Este criterio no reconoce el papel medular que desempeña la dimensión ético moral en el ámbito social. El propósito fundamental de este trabajo es realizar un enfoque crítico del problema, tal y como se presenta en la realidad cubana actual, partiendo de la concepción martiana y marxista en la obra cultural de la Revolución Cubana