Asteroid Redirect Crewed Mission Space Suit and EVA System Architecture Trade Study

The Asteroid Redirect Crewed Mission (ARCM) requires a Launch/Entry/Abort (LEA) suit capability and short duration Extra Vehicular Activity (EVA) capability for Orion. The EVAs will involve a two-person crew for approximately four hours. Currently, two EVAs are planned with one contingency EVA in reserve. Providing this EVA capability is very challenging due to system level constraints and a new and unknown environment. The goal of the EVA architecture for ARCM is one that builds upon previously developed technologies and lessons learned, and that accomplishes the ARCM mission while providing a stepping stone to future missions and destinations. The primary system level constraints are to 1) minimize system mass and volume and 2) minimize the interfacing impacts to the baseline Orion design. In order to minimize the interfacing impacts and to not perturb the baseline Orion schedule, the concept of adding "kits" to the baseline system is proposed. These kits consist of: an EVA kit (converts LEA suit to EVA suit), EVA Servicing and Recharge Kit (provides suit consumables), the EVA Tools, Translation Aids & Sample Container Kit (the tools and mobility aids to complete the tasks), the EVA Communications Kit (interface between the EVA radio and the MPCV), and the Cabin Repress Kit (represses the MPCV between EVAs). This paper will focus on the trade space, analysis, and testing regarding the space suit (pressure garment and life support system). Historical approaches and lessons learned from all past EVA operations were researched. Previous and current, successfully operated EVA hardware and high technology readiness level (TRL) hardware were evaluated, and a trade study was conducted for all possible pressure garment and life support options. Testing and analysis was conducted and a recommended EVA system architecture was proposed. Pressure garment options that were considered for this mission include the currently in-use ISS EVA Mobility Unit (EMU), all variations of the Advanced Crew Escape Suit (ACES), and the Exploration Z-suit. For this mission, the pressure garment that was selected is the Modified ACES (MACES) with EVA enhancements. Life support options that were considered included short closed-loop umbilicals, long open-loop umbilicals, the currently in-use ISS EMU Portable Life Support System (PLSS), and the currently in development Exploration PLSS. For this mission, the life support option that was selected is the Exploration PLSS. The greatest risk in the proposed architecture is viewed to be the comfort and mobility of the baseline MACES and the delicate balance between adding more mobility features while not compromising landing safety. Feasibility testing was accomplished in low fidelity analogs and in the JSC Neutral Buoyancy Laboratory (NBL) to validate the concept before a final recommendation on the architecture was made. The proposed architecture was found to meet the mission constraints, but much more work is required to determine the details of the required suit upgrades, the integration with the PLSS, and the rest of the tools and equipment required to accomplish the mission. This work and further definition of the remaining kits will be conducted in government fiscal year 14

Molecular mechanism of Gαi activation by non-GPCR proteins with a Gα-Binding and Activating motif

Heterotrimeric G proteins are quintessential signalling switches activated by nucleotide exchange on Gα. Although activation is predominantly carried out by G-protein-coupled receptors (GPCRs), non-receptor guanine-nucleotide exchange factors (GEFs) have emerged as critical signalling molecules and therapeutic targets. Here we characterize the molecular mechanism of G-protein activation by a family of non-receptor GEFs containing a Gα-binding and -activating (GBA) motif. We combine NMR spectroscopy, computational modelling and biochemistry to map changes in Gα caused by binding of GBA proteins with residue-level resolution. We find that the GBA motif binds to the SwitchII/α3 cleft of Gα and induces changes in the G-1/P-loop and G-2 boxes (involved in phosphate binding), but not in the G-4/G-5 boxes (guanine binding). Our findings reveal that G-protein-binding and activation mechanisms are fundamentally different between GBA proteins and GPCRs, and that GEF-mediated perturbation of nucleotide phosphate binding is sufficient for Gα activation

Systematics of Moduli Stabilization, Inflationary Dynamics and Power Spectrum

We study the scalar sector of type IIB superstring theory compactified on Calabi-Yau orientifolds as a place to find a mechanism of inflation in the early universe. In the large volume limit, one can stabilize the moduli in stages using perturbative method. We relate the systematics of moduli stabilization with methods to reduce the number of possible inflatons, which in turn lead to a simpler inflation analysis. Calculating the order-of-magnitude of terms in the equation of motion, we show that the methods are in fact valid. We then give the examples where these methods are used in the literature. We also show that there are effects of non-inflaton scalar fields on the scalar power spectrum. For one of the two methods, these effects can be observed with the current precision in experiments, while for the other method, the effects might never be observable.Comment: 20 pages, JHEP style; v.2 and v.3: typos fixed, discussion and references adde

Genetic Architecture of Flowering-Time Variation in Arabidopsis thaliana

The onset of flowering is an important adaptive trait in plants. The small ephemeral species Arabidopsis thaliana grows under a wide range of temperature and day-length conditions across much of the Northern hemisphere, and a number of flowering-time loci that vary between different accessions have been identified before. However, only few studies have addressed the species-wide genetic architecture of flowering-time control. We have taken advantage of a set of 18 distinct accessions that present much of the common genetic diversity of A. thaliana and mapped quantitative trait loci (QTL) for flowering time in 17 F2 populations derived from these parents. We found that the majority of flowering-time QTL cluster in as few as five genomic regions, which include the locations of the entire FLC/MAF clade of transcription factor genes. By comparing effects across shared parents, we conclude that in several cases there might be an allelic series caused by rare alleles. While this finding parallels results obtained for maize, in contrast to maize much of the variation in flowering time in A. thaliana appears to be due to large-effect alleles

Chemical and kinematical properties of BSSs and HB stars in NGC 6397

We used three sets of high-resolution spectra acquired with the multifiber facility FLAMES at the Very Large Telescope of the European Southern Observatory to investigate the chemical and kinematical properties of a sample of 42 horizontal branch (HB) stars, 18 Blue Straggler Stars (BSSs) and 86 main sequence turn-off and sub-giant branch stars in the nearby globular cluster NGC 6397. We measured rotational velocities and Fe, O and Mg abundances. All the unevolved stars in our sample turn out to have low rotational velocites (v sin i< 10\kms), while HB stars and BSSs show a broad distribution, with values ranging from 0 to 70 \kms. For HB stars with T<10500 K there is a clear temperature-oxygen anti-correlation, that can be understood if the star position along the HB is mainly determined by the He content. The hottest BSSs and HB stars (with temperatures T>8200 K and T> 10500 K, respectively) also show significant deviations in their iron abundance with respect to the cluster metallicity (as traced by the unevolved stars, [Fe/H]=-2.12). While similar chemical patterns have been already observed in other hot HB stars, this is the first evidence ever collected for BSSs. We interprete these abundance anomalies as due to the metal radiative levitation, occurring in stars with shallow or no convective envelopes

Cover crop productivity and subsequent soybean yield in the western Corn Belt

Cover crops (CC) in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] rotations may prevent N loss and provide other ecosystem services but CC productivity in the western Corn Belt is limited by the short growing season. Our objective was to assess CC treatment and planting practice effects on CC biomass, spring soil nitrate concentrations, and soybean yield at two rainfed sites in eastern and one irrigated site in south-central Nebraska over 4 yr. Cover crop treatments (cereal rye [Secale cereale L.] [RYE] and a mix of rye, legume, and brassica species [MIX]) were planted by broadcast interseeding into corn stands in September (pre-harvest broadcast) or drilling after corn harvest (post-harvest drilled) and terminated 2 wk before planting soybean. Cover crop biomass and N uptake varied between years, but generally at the eastern sites, pre-harvest broadcasting produced more biomass than post-harvest drilling (1.64 and 0.79 Mg ha−1, respectively) and had greater N uptake (37 and 24 kg ha−1, respectively). At the south-central site, post-harvest drilling produced more than pre-harvest broadcasting (1.44 and 1.20 Mg ha−1, respectively). RYE had more biomass than MIX (1.41 and 1.09 Mg ha−1, respectively), but the same N uptake. Soil nitrate reductions after CC were small. In 3 of 12 site-years, soybean yielded less after pre-harvest CC. Yield reductions were not correlated to CC biomass, but were likely due to greater weed pressure. High CC productivity is necessary for high N uptake, and requires site-specific selection of planting practice and CC treatments

Distribution of espM and espT among enteropathogenic and enterohaemorrhagic Escherichia coli

Enterohaemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) translocate dozens of type III secretion system effectors, including the WxxxE effectors Map, EspM and EspT that activate Rho GTPases. While map, which is carried on the LEE pathogenicity island, is absolutely conserved among EPEC and EHEC strains, the prevalence of espM and espT is not known. Here we report the results of a large screen aimed at determining the prevalence of espM and espT among clinical EPEC and EHEC isolates. The results suggest that espM, detected in 51 % of the tested strains, is more commonly found in EPEC and EHEC serogroups that are linked to severe human infections. In contrast, espT was absent from all the EHEC isolates and was found in only 1.8 % of the tested EPEC strains. Further characterization of the virulence gene repertoire of the espT-positive strains led to the identification of a new ζ2 intimin variant. All the espT-positive strains but two contained the tccP gene. espT was first found in Citrobacter rodentium and later in silico in EPEC E110019, which is of particular interest as this strain was responsible for a particularly severe diarrhoeal outbreak in Finland in 1987 that affected 650 individuals in a school complex and an additional 137 associated household members. Comparing the protein sequences of EspT to that of E110019 showed a high level of conservation, with only three strains encoding EspT that differed in 6 amino acids. At present, it is not clear why espT is so rare, and what impact EspM and EspT have on EPEC and EHEC infection

Relación del transporte prehospitalario con las complicaciones y la mortalidad del infarto agudo de miocardio.

Introducción: el infarto agudo de miocardio es la principal afección cardiovascular que causa complicaciones letales si no se instaura el tratamiento de reperfusión oportuno. Es crucial el funcionamiento de un sistema médico de traslado hacia un centro hospitalario que permita aumentar la sobrevivencia y la calidad de vida de los afectados.Objetivo: relacionar el tipo de transporte prehospitalario con el municipio de procedencia, aplicación de trombolisis, complicaciones y mortalidad general en pacientes con infarto agudo de miocardio.Métodos: se realizó un trabajo descriptivo, transversal, analítico, en 100 pacientes ingresados con infarto agudo de miocardio en la unidad de cuidados intensivos del Hospital Docente “Aleida Fernández” de Güines, desde el primero de diciembre de 2011 hasta el 30 de noviembre de 2012. Las variables estudiadas fueron la edad, el sexo, tipo de traslado hacia el hospital, municipio de procedencia, aplicación de trombolítico, complicaciones y mortalidad general por insuficiencia cardiaca, choque cardiogénico y arritmias cardiacas. Se calcularon las frecuencias absolutas y relativas; se aplicó Ji Cuadrado para determinar la relación entre variables.Resultados: predominó la edad de 60 a 79 años y el sexo masculino. El transporte más utilizado fue el apoyo vital básico, prevalecieron los pacientes procedentes de Güines. Fue más numerosa la no aplicación de trombolítico. Se observó una elevada incidencia de complicaciones y mortalidad, estas predominaron en los traslados en el apoyo vital básico. Existió relación estadística significativa entre el tipo de transporte y el municipio de procedencia. Conclusión: el tipo de traslado prehospitalario incide en las complicaciones y la mortalidad general de pacientes con infarto agudo de miocardio

Intervención educativa sobre conocimientos de electrocardiografía básica en residentes de medicina general integral

Introducción: es importante que los residentes de medicina general integral muestren habilidades para la interpretación del electrocardiograma, dado el predominio en la población general de afecciones cardiovasculares. Objetivo: mostrar el nivel de conocimientos que alcanzan médicos residentes de medicina general integral en electrocardiografía después de recibir un curso de entrenamiento. Material y Método: estudio cuasi experimental analítico, de intervención educativa, con 25 residentes de medicina general integral del Policlínico Docente «Marta Martínez» de Güines; desde el primero de noviembre de 2017 hasta el 31 de enero del 2018. Los datos se obtuvieron de un cuestionario de examen aplicado antes y después de impartir a los residentes un curso de electrocardiografía básica. Se realizó un análisis de comparación de medias y de varianza de las calificaciones promedio entre los grupos. Se estableció un nivel de significación alfa de 0.05 con intervalo de confianza de 95 %. Resultados: predominaron los residentes de segundo año y del sexo femenino. Todos los médicos evaluados incrementaron sus calificaciones después del curso de entrenamiento. Los residentes masculinos de primer año obtuvieron las mejores calificaciones en el examen anterior y posterior al curso impartido. Los temas sobre electrocardiograma normal y los signos de crecimiento auricular mostraron las puntuaciones más elevadas, las manifestaciones de bloqueo de rama del haz de His tuvieron las más bajas. Conclusión: aunque existieron diferencias en la adquisición de conocimientos sobre electrocardiografía básica en residentes de medicina general integral, estos elevaron su nivel después del curso de entrenamiento

Intervención educativa sobre conocimientos de electrocardiografía básica en residentes de medicina general integral

Introducción: es importante que los residentes de medicina general integral muestren habilidades para la interpretación del electrocardiograma, dado el predominio en la población general de afecciones cardiovasculares. Objetivo: mostrar el nivel de conocimientos que alcanzan médicos residentes de medicina general integral en electrocardiografía después de recibir un curso de entrenamiento. Material y Método: estudio cuasi experimental analítico, de intervención educativa, con 25 residentes de medicina general integral del Policlínico Docente «Marta Martínez» de Güines; desde el primero de noviembre de 2017 hasta el 31 de enero del 2018. Los datos se obtuvieron de un cuestionario de examen aplicado antes y después de impartir a los residentes un curso de electrocardiografía básica. Se realizó un análisis de comparación de medias y de varianza de las calificaciones promedio entre los grupos. Se estableció un nivel de significación alfa de 0.05 con intervalo de confianza de 95 %. Resultados: predominaron los residentes de segundo año y del sexo femenino. Todos los médicos evaluados incrementaron sus calificaciones después del curso de entrenamiento. Los residentes masculinos de primer año obtuvieron las mejores calificaciones en el examen anterior y posterior al curso impartido. Los temas sobre electrocardiograma normal y los signos de crecimiento auricular mostraron las puntuaciones más elevadas, las manifestaciones de bloqueo de rama del haz de His tuvieron las más bajas. Conclusión: aunque existieron diferencias en la adquisición de conocimientos sobre electrocardiografía básica en residentes de medicina general integral, estos elevaron su nivel después del curso de entrenamiento