On the 2:1 Orbital Resonance in the HD 82943 Planetary System

We present an analysis of the HD 82943 planetary system based on a radial velocity data set that combines new measurements obtained with the Keck telescope and the CORALIE measurements published in graphical form. We examine simultaneously the goodness of fit and the dynamical properties of the best-fit double-Keplerian model as a function of the poorly constrained eccentricity and argument of periapse of the outer planet's orbit. The fit with the minimum chi_{nu}^2 is dynamically unstable if the orbits are assumed to be coplanar. However, the minimum is relatively shallow, and there is a wide range of fits outside the minimum with reasonable chi_{nu}^2. For an assumed coplanar inclination i = 30 deg. (sin i = 0.5), only good fits with both of the lowest order, eccentricity-type mean-motion resonance variables at the 2:1 commensurability, theta_1 and theta_2, librating about 0 deg. are stable. For sin i = 1, there are also some good fits with only theta_1 (involving the inner planet's periapse longitude) librating that are stable for at least 10^8 years. The libration semiamplitudes are about 6 deg. for theta_1 and 10 deg. for theta_2 for the stable good fit with the smallest libration amplitudes of both theta_1 and theta_2. We do not find any good fits that are non-resonant and stable. Thus the two planets in the HD 82943 system are almost certainly in 2:1 mean-motion resonance, with at least theta_1 librating, and the observations may even be consistent with small-amplitude librations of both theta_1 and theta_2.Comment: 24 pages, including 10 figures; accepted for publication in Ap

Characterizing Deep-Learning I/O Workloads in TensorFlow

The performance of Deep-Learning (DL) computing frameworks rely on the performance of data ingestion and checkpointing. In fact, during the training, a considerable high number of relatively small files are first loaded and pre-processed on CPUs and then moved to accelerator for computation. In addition, checkpointing and restart operations are carried out to allow DL computing frameworks to restart quickly from a checkpoint. Because of this, I/O affects the performance of DL applications. In this work, we characterize the I/O performance and scaling of TensorFlow, an open-source programming framework developed by Google and specifically designed for solving DL problems. To measure TensorFlow I/O performance, we first design a micro-benchmark to measure TensorFlow reads, and then use a TensorFlow mini-application based on AlexNet to measure the performance cost of I/O and checkpointing in TensorFlow. To improve the checkpointing performance, we design and implement a burst buffer. We find that increasing the number of threads increases TensorFlow bandwidth by a maximum of 2.3x and 7.8x on our benchmark environments. The use of the tensorFlow prefetcher results in a complete overlap of computation on accelerator and input pipeline on CPU eliminating the effective cost of I/O on the overall performance. The use of a burst buffer to checkpoint to a fast small capacity storage and copy asynchronously the checkpoints to a slower large capacity storage resulted in a performance improvement of 2.6x with respect to checkpointing directly to slower storage on our benchmark environment.Comment: Accepted for publication at pdsw-DISCS 201

New Central American and Mexican Enaphalodes Haldeman, 1847 (Coleoptera: Cerambycidae) with taxonomic notes and a key to species

A review of Enaphalodes Haldeman, 1847 is presented. Descriptions of four new species of Enaphalodes are included: E. antonkozlovi, sp. nov. from Costa Rica, E. bingkirki, sp. nov. from Nicaragua, E. monzoni, sp. nov. from Guatemala, and E. cunninghami, sp. nov. from Mexico. Enaphalodes senex (Bates, 1884) is revalidated and it is newly recorded from Nicaragua and Guatemala. A key to the 15 currently recognized species of Enaphalodes is included

Hand-to-hand: an intermanual illusion of movement

Apparent tactile motion has been shown to occur across many contiguous parts of the body, such as fingers, forearms, and back. A recent study demonstrated the possibility of eliciting the illusion of movement from one hand to the other when interconnected by a tablet. In this paper, we explore intermanual apparent tactile motion without any object between them. In a series of psychophysical experiments, we determine the control space for generating smooth and consistent motion, using two vibrating handles which we refer to as the Hand-to-Hand vibrotactile device. In a first experiment, we investigated the occurrence of the phenomenon (i.e., movement illusion) and the generation of a perceptive model. In a second experiment, based on those results, we investigated the effect of hand postures on the illusion. Finally, in a third experiment, we explored two visuo-tactile matching tasks in a multimodal VR setting. Our results can be applied in VR applications with intermanual tactile interactions

Lesbian, Gays, Bisexuals, Transgendered, and Queer (LGBTQ) People and Adult Education: An Examination of Literature in Adult Education 2010-2020

We discuss our review of LGBTQ issues in adult education journals between 2010 and 2020. We pose several topics for discussion based on our findings

Factores competitivos: mergulhando no turismo de surf

O objectivo principal deste estudo é aprofundar o conhecimento sobre o turismo de surf através da compreensão dos seus factores competitivos. O estudo procura também compreender se a satisfação dos turistas de surf tem uma influência positiva nas recomendações feitas a outras pessoas e se as recomendações de destinos feitas por turistas de surf influenciam positivamente as decisões de compra doutros turistas de surf. A metodologia foi utilizada no sentido de inquirir a população de pessoas para quem a participação activa no surf é a motivação primária para a escolha do destino de viagem. Obteve-se uma amostra de 201 indivíduos. Os resultados comprovaram que uma surf trip que ofereça os principais factores competitivos do turismo de surf, nomeadamente a segurança pessoal, a qualidade do meio ambiente, as preocupações com a saúde, as datas fiáveis, a qualidade das refeições, a cultura local, o preço, a probabilidade de encontrar locais secretos, a facilidade de acesso, a possibilidade de encontrar outros surfistas, a taxa local de câmbio, o leque de actividades alternativas, as condições para famílias, e a reputação do destino de surf, conduz à satisfação dos consumidores. As conclusões desta dissertação poderão apoiar a tomada de decisões sobre a composição do produto e aumentar o conhecimento sobre as necessidades e expectativas reais dos turistas de surf.The main purpose of this study is to increase the knowledge of surf tourism by understanding its competitive factors. The study also aims at understanding whether the satisfaction of surf tourists has a positive influence on recommendations made to other people, and whether recommendations made by surf tourists have a positive impact on the purchase decisions of other surf tourists. The methodology was used to question the population of people for whom the active participation in the sport of surfing is the primary motivation for destination selection. A sample of 201 surf tourists was analysed. Results showed that a surf trip that offers the main competitive factors of surf tourism, namely personal safety, quality of natural environment, health concerns, reliable dates, high quality meals, local culture, price, secret locations, ease of access, meeting other travellers, local rate of exchange, range of activities available, facilities for families, and reputation of the surf destination, leads to consumer satisfaction. The findings may support product decision-making and increase the knowledge of the needs and expectations of surf tourists.http://hdl.handle.net/10071/407

Studies Needed to Address Public Health Challenges of the 2009 H1N1 Influenza Pandemic: Insights from Modeling

In light of the 2009 influenza pandemic and potential future pandemics, Maria Van Kerkhove and colleagues anticipate six public health challenges and the data needed to support sound public health decision making.The authors acknowledge support from the Bill & Melinda Gates Foundation (MDVK, CF, NMF); Royal Society (CF); Medical Research Council (MDVK, CF, PJW, NMF); EU FP7 programme (NMF); UK Health Protection Agency (PJW); US National Institutes of Health Models of Infectious Disease Agent Study program through cooperative agreement 1U54GM088588 (ML); NIH Director's Pioneer Award, DP1-OD000490-01 (DS); EU FP7 grant EMPERIE 223498 (DS); the Wellcome Trust (DS); 3R01TW008246-01S1 from Fogerty International Center and RAPIDD program from Fogerty International Center with the Science & Technology Directorate, Department of Homeland Security (SR); and the Institut de Veille Sanitaire Sanitaire funded by the French Ministry of Health (J-CD). The funders played no role in the decision to submit the article or in its preparation

Stable isotope analysis of multiple tissues from chick carcassess of three pygoscelid penguins in Antarctica

Varios tipos de tejidos animales son empleados para el análisis de isótopos estables, considerando el período de tiempo que cada tejido refleja y dependiendo de su disponibilidad para colección. Aquí, hemos investigado los valores isotópicos (δ13C y δ15N) de cuatro tejidos (pluma, piel, uña y hueso) colectados de cadáveres de pichones de las tres especies de pingüinos pigoscélidos con el objetivo de comparar precisión y variabilidad de la información obtenida. Las muestras fueron colectadas en la Isla 25 de Mayo/King George durante el verano austral 2017/18. Los cadáveres de pichones son comúnmente encontrados alrededor de colonias activas y el muestreo oportunista puede fácilmente ser realizado minimizando el disturbio en la colonia. Un total de 25–36 cadáveres por especie fueron muestreados en colonias de Pingüinos Adelia Pygoscelis adeliae, Pingüinos Papúa P. papua, y Pingüinos Barbijo P. antarcticus. Un modelo lineal mixto mostró que los valores de δ13C variaron dependiendo del tejido presumiblemente debido a la discriminación isotópica específica a cada uno de ellos. En cambio, el único tejido significativamente diferente para δ15N fue la uña. La información reveló diferencias dietarias entre especies, exhibiendo el Pingüino Papúa los valores más altos. Asimismo, los Pingüinos Barbijo mostraron valores más altos de δ13C que los Pingüinos Adelia, aunque esta diferencia no fue significativa. Los Papúa mostraron la mayor variabilidad para todos los tejidos. La piel exhibió la mayor variabilidad en las tres especies y fue el tejido menos confiable para análisis de isótopos estables; mientras que las uñas mostraron la menor variabilidad. Los valores obtenidos de dos huesos distintos (tibiatarso y coracoides) no mostraron diferencias significativas, indicando que el muestreo de otros huesos probablemente resultará en valores similares. Nuestros resultados brindan información para poder estimar la composición de la dieta con precisión y comparar diferentes especies y/o colonias abandonadas y activas mediante el muestreo oportunista.Many types of animal tissues are increasingly being used for stable isotope analysis, with their application dependent on the time frame they reflect and their availability for collection. Here, we investigated the isotopic values (δ13C and δ15N) of four tissues (feather, skin, toenail, and bone) collected from fledgling-period chick carcasses of three species of pygoscelid penguins to compare the variability and accuracy of the data among tissues. Samples were collected at 25 de Mayo/King George Island during the 2017/18 austral summer. Chick carcasses are commonly found at active penguin colonies, and “opportunistic sampling” can easily be performed without disturbing nesting penguins. A total of 25-36 carcasses per species were sampled at active colonies of Adélie Pygoscelis adeliae, Gentoo P. papua, and Chinstrap P. antarcticus penguins. A linear mixed model showed that δ13C values varied significantly between tissues, presumably due to tissue-specific isotopic discrimination. In contrast, the only tissue with significantly different δ15N values was toenail. Stable isotope data revealed dietary differences among species, with Gentoo Penguins having higher average isotopic values in tissues compared to Adélie and Chinstrap penguins. In addition, Chinstrap Penguins showed a consistent, but not statistically significant, trend in having higher δ13C values compared to Adélie Penguins. Gentoo Penguins displayed the highest isotopic variability of any species for all tissues. Isotopic composition was most variable in skin in all three species making skin the least reliable tissue for isotope analysis, whereas isotopic values were least variable in toenails. Comparison of isotopic values between two bones (tibiotarsus and coracoid) showed no significant differences in isotopic values, indicating that when the same bone is not available for sampling from carcasses, sampling of any major skeletal element is likely to provide a meaningful comparison. These results allow for more informed opportunistic sampling to accurately estimate and compare penguin diet among species and between ancient and active colonies.Fil: Ciriani, Yanina Anabella. University of North Carolina; Estados UnidosFil: Juares, Mariana Alejandra. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Santos, Maria Mercedes. Ministerio de Relaciones Exteriores, Comercio Internacional y Culto. Direccion Nacional del Antártico; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Emslie, Steven Douglas. University of North Carolina; Estados Unido