7,228 research outputs found
Multi-scale path planning for a planetary exploration vehicle with multiple locomotion modes
Planetary exploration vehicles (rovers) can encounter with a great variety of
situations. Most of them are related to the terrain, which can cause the end of
the mission if these vehicles are not able to traverse it. It was the case of Spirit
rover, which got stuck in loose sand, making it impossible to continue advancing.
A solution to this is to make rovers capable of modifying their locomotion to
traverse terrains with particular terramechanic parameters.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Evaluación financiera de producción de pejelagarto (atractosteus tropicus): Caso cooperativa de producción pesquera acuícola "El pejelagarto", S.C. de R.L.
Se evalúo la rentabilidad de la producción de pejelagarto (Atractosteus tropicus) en dos modalidades de cultivo, en condiciones de cautiverio y en cautiverio en asociación con la mojarra castarrica y tilapia en la Sociedad Cooperativa de Producción Acuícola "El Pejelagarto", localizada en Sabancuy, municipio de Carmen, Campeche, México. Para tal efecto, se utilizaron los registros de 10 años para el cálculo de los indicadores de evaluación económica siguientes para el primer modo de cultivo: valor actual neto (VAN), relación beneficio-costo (B/C), relación beneficio-inversión neta (K/N) y la tasa interna de retorno (TIR). Los resultados obtenidos, para este período, fueron: VAN = 119,825.00, B/C = 1.08, N/K = 1.88 y TIR = 25.6%. Los indicadores para el cultivo en asociación fueron VAN = 629,254, B/C = 1.43, N/K = 10.15 y TIR = 145.0%. Con base en los resultados de los indicadores, se concluye que el proyecto productivo es viable en sus dos modalidades de cultivo, desde el punto de vista económico; por lo anterior, la cría, producción y comercialización de pejelagarto, tiene una gran oportunidad de negocio, por ser una especie con demanda, dentro y fuera de la región, por su rusticidad en la cría además de ser considerado un platillo exótico
OH rotational lines as a diagnostic of the warm neutral gas in galaxies
We present Infrared Space Observatory (ISO) observations of several OH, CH
and H2O rotational lines toward the bright infrared galaxies NGC253 and
NGC1068. As found in the Galactic clouds in SgrB2 and Orion, the extragalactic
far-IR OH lines change from absorption to emission depending on the physical
conditions and distribution of gas and dust along the line of sight. As a
result, most of the OH rotational lines that appear in absorption toward NGC253
are observed in emission toward NGC1068. We show that the far-IR spectrum of OH
can be used as a powerful diagnostic to derive the physical conditions of
extragalactic neutral gas. In particular, we find that a warm (Tk~150 K, n(H2)<
5 10^4 cm^-3) component of molecular gas with an OH abundance of 10^{-7} from
the inner <15'' can qualitatively reproduce the OH lines toward NGC253. Similar
temperatures but higher densities (5 10^5 cm^-3) are required to explain the OH
emission in NGC1068.Comment: 5 pages, 4 figures, accepted in ApJ Part I (2004, October 6
Extending and Measuring the Quality of Fresh-Cut Fruit and Vegetables: a Review
The market sales of ready - to - use vegetables have grown rapidly in recent decades as a result of changes in consumer attitudes especially consumption of fresh-cut lettuce and carrot due to their use in prepared salads. Chlorine solutions have been widely used to sanitise fruit and vegetables in the fresh-cut industry. However, the association of chlorine with the possible formation of carcinogenic chlorinated compounds in water has called into question the use of chlorine in food processing. There is a real need to find alternatives for preservation of fresh-cut fruit and vegetables in order to improve the efficacy of washing treatments. Alternatives or modified methods have been proposed as antioxidants, irradiation, ozone, organics acids, modified atmosphere packaging, whey permeate etc.: however, none have yet gained widespread acceptance by the industry. For this reason the devlopment of alternatives and markers in order to measure the efficacy of these alternatives are needed
EVALUACIÓN FINANCIERA DE PRODUCCIÓN DE PEJELAGARTO (Atractosteus tropicus): CASO COOPERATIVA DE PRODUCCIÓN PESQUERA ACUÃCOLA “EL PEJELAGARTOâ€, S.C. DE R.L.
The profitability of production of pejelagarto (Atractosteus tropicus) was evaluated in two types of cultivation, in captivity conditions and in captivity conditions in association with the Mojarra Castarrica and Tilapia at the Aquaculture Production Cooperative Society "El Pejelagarto", located in Sabancuy, municipality of Carmen, Campeche, Mexico. For this purpose, the records of 10 years ago were used to calculate the following indicators of economic evaluation for the first mode of cultivation: Net Present Value (NPV), Benefit-Cost Ratio (B / C), Net Benefit-Investment (K / N) and Internal Rate of Return (IRR). The results obtained for this period were: NPV = 119,825.00, B / C = 1.08, N / K = 1.88 and IRR = 25.6%. The indicators for cultivation in association were NPV = 629.254, B / C = 1.43, N / K = IRR = 10.15 and 145.0%. Based on the results of the indicators, it is concluded that the project is feasible in its two forms of cultivation, from the economic point of view thus, the breeding, production and marketing of pejelagarto, has a great business opportunity, because of being species with demand, both within and outside of the region, for their rusticity in breeding as well as being considered an exotic dish.Profitability, economic indicators, pejelagarto., Agribusiness,
Time-coded neurotransmitter release at excitatory and inhibitory synapses.
Communication between neurons at chemical synapses is regulated by hundreds of different proteins that control the release of neurotransmitter that is packaged in vesicles, transported to an active zone, and released when an input spike occurs. Neurotransmitter can also be released asynchronously, that is, after a delay following the spike, or spontaneously in the absence of a stimulus. The mechanisms underlying asynchronous and spontaneous neurotransmitter release remain elusive. Here, we describe a model of the exocytotic cycle of vesicles at excitatory and inhibitory synapses that accounts for all modes of vesicle release as well as short-term synaptic plasticity (STSP). For asynchronous release, the model predicts a delayed inertial protein unbinding associated with the SNARE complex assembly immediately after vesicle priming. Experiments are proposed to test the model's molecular predictions for differential exocytosis. The simplicity of the model will also facilitate large-scale simulations of neural circuits
Dynamic path planning for reconfigurable rovers using a multi-layered grid
Autonomy on rovers is desirable in order to extend the traversed distance, and therefore, maximize the number
of places visited during the mission. It depends heavily on the information that is available for the traversed
surface on other planet. This information may come from the vehicle’s sensors as well as from orbital images.
Besides, future exploration missions may consider the use of reconfigurable rovers, which are able to execute
multiple locomotion modes to better adapt to different terrains. With these considerations, a path planning
algorithm based on the Fast Marching Method is proposed. Environment information coming from different
sources is used on a grid formed by two layers. First, the Global Layer with a low resolution, but high extension
is used to compute the overall path connecting the rover and the desired goal, using a cost function that takes
advantage of the rover locomotion modes. Second, the Local Layer with higher resolution but limited distance
is used where the path is dynamically repaired because of obstacle presence. Finally, we show simulation and
field test results based on several reconfigurable and non-reconfigurable rover prototypes and a experimental
terrain
New Biochemical Insights into the Mechanisms of Pulmonary Arterial Hypertension in Humans
Diagnosis of pulmonary arterial hypertension (PAH) is difficult due to the lack of specific clinical symptoms and biomarkers, especially at early stages. We compared plasma metabolic fingerprints of PAH patients (n = 20) with matched healthy volunteers (n = 20) using, for the first time, untargeted multiplatform metabolomics approach consisting of high-performance liquid and gas chromatography coupled with mass spectrometry. Multivariate statistical analyses were performed to select metabolites that contribute most to groups' classification (21 from liquid in both ionization modes and 9 from gas chromatography-mass spectrometry). We found metabolites related to energy imbalance, such as glycolysis-derived metabolites, as well as metabolites involved in fatty acid, lipid and amino acid metabolism. We observed statistically significant changes in threitol and aminomalonic acid in PAH patients, which could provide new biochemical insights into the pathogenesis of the disease. The results were externally validated on independent case and control cohorts, confirming up to 16 metabolites as statistically significant in the validation study. Multiplatform metabolomics, followed by multivariate chemometric data analysis has a huge potential for explaining pathogenesis of PAH and for searching potential and new more specific and less invasive markers of the disease.This research was supported by the Polish National Science Center (2014/13/N/NZ7/04231), the Spanish Ministry of Economy and Competitiveness (MINECO) (SAF2014-58920R), by the Fondo de Investigacion Sanitaria del Instituto de Salud Carlos III and co-funding by Fondo Europeo de Desarrollo Regional (FEDER) (PI14-01427), and by the quality-promoting subsidy from the Ministry of Science and Higher Education of Poland, Leading National Research Centre (KNOW programme 2012-2017). The CNIC is supported by the Spanish Ministry of Economy and Competitiveness and the Pro-CNIC Foundation, and is a Severo Ochoa Center of Excellence (MINECO award SEV-2015-0505). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.S
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