93 research outputs found

    Robotic Visual Tracking of Relevant Cues in Underwater Environments with Poor Visibility Conditions

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    Using visual sensors for detecting regions of interest in underwater environments is fundamental for many robotic applications. Particularly, for an autonomous exploration task, an underwater vehicle must be guided towards features that are of interest. If the relevant features can be seen from the distance, then smooth control movements of the vehicle are feasible in order to position itself close enough with the final goal of gathering visual quality images. However, it is a challenging task for a robotic system to achieve stable tracking of the same regions since marine environments are unstructured and highly dynamic and usually have poor visibility. In this paper, a framework that robustly detects and tracks regions of interest in real time is presented. We use the chromatic channels of a perceptual uniform color space to detect relevant regions and adapt a visual attention scheme to underwater scenes. For the tracking, we associate with each relevant point superpixel descriptors which are invariant to changes in illumination and shape. The field experiment results have demonstrated that our approach is robust when tested on different visibility conditions and depths in underwater explorations

    Equilibration of Concentrated Hard Sphere Fluids

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    We report a systematic molecular dynamics study of the isochoric equilibration of hard-sphere fluids in their metastable regime close to the glass transition. The thermalization process starts with the system prepared in a non-equilibrium state with the desired final volume fraction {\phi} but with a prescribed non-equilibrium static structure factor S_0(k; {\phi}). The evolution of the {\alpha}- relaxation time {\tau}{\alpha} (k) and long-time self-diffusion coefficient DL as a function of the evolution time tw is then monitored for an array of volume fractions. For a given waiting time the plot of {\tau}{\alpha} (k; {\phi}, tw) as a function of {\phi} exhibits two regimes corresponding to samples that have fully equilibrated within this waiting time ({\phi} \leq {\phi}(c) (tw)), and to samples for which equilibration is not yet complete ({\phi} \geq {\phi}(c) (tw)). The crossover volume fraction {\phi}(c) (tw) increases with tw but seems to saturate to a value {\phi}(a) \equiv {\phi}(c) (tw \rightarrow \infty) \approx 0.582. We also find that the waiting time t^(eq)_w({\phi}) required to equilibrate a system grows faster than the corresponding equilibrium relaxation time, t^(eq)({\phi}) \approx 0.27 \times [{\tau}{\alpha} (k; {\phi})]^1.43, and that both characteristic times increase strongly as {\phi} approaches {\phi}^(a), thus suggesting that the measurement of equilibrium properties at and above {\phi}(a) is experimentally impossible

    Amphibians and reptiles encountered during an expedition to Panama

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    Abstract.—During a recent expedition to five protected areas in Panama (Parque Nacional Volcán Barú andReserva Forestal Fortuna, Chiriquí Province; Parque Nacional Santa Fe, Veraguas Province; Parque Nacional Darien,Rancho Frío, Darien Province; and Mamoni Valley Private Reserve, Panama Province), we observed 95 species ofamphibians and reptiles (51 amphibians and 44 reptiles). We made opportunistic observations of many of them,including noteworthy updates on the conservation status of critically endangered or endangered taxa (Atelopus glyphus,A. limosus, A. varius, Isthmohyla angustilineata, I. tica, Oedipina grandis), the third and fourth distribution records forPanama of Trilepida macrolepis, the second distribution report of Leptophis cupreus for the country, the fourth countryrecord of Bachia blairi, new behavior and maximum size for Oophaga vicentei, and the second known specimen ofNorops triumphalis

    Planeamiento estratégico para el sector ganadero de la Región Cajamarca

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    El objetivo del presente trabajo de investigación es la de elaborar un planeamiento estratégico que permita al sector ganadero de la región Cajamarca pasar de una situación actual a una situación futura deseada, su desarrollo esto basado considerando su potencial ganadero, las condiciones de mercado existentes, en la disponibilidad de los diversos recursos presentes en la región, así como el interés por parte del gobierno en el desarrollo del sector. El desarrollo del plan estratégico ha considerado un análisis interno y externo que ha permitido determinar un marco situacional con el cual se establecieron estrategias que coadyuven al logro de objetivos de corto y largo plazo enfocados principalmente en el desarrollo del sector. Debe indicarse que la situación actual del sector presenta situaciones complejas como el hecho de que la producción ganadera se encuentra atomizada, además de la fuerte presencia de actividades contrarias como la minería, sin embargo el potencial e interés en desarrollar a la región como zona ganadera se presenta como una oportunidad que permitirá lograr desarrollo y bienestar para los diferentes grupos de interés. Finalmente, la situación presenta un escenario favorable para la implementación de medidas que permitan impulsar el desarrollo del sector, la mejoría en los procesos de producción, su posicionamiento en el mercado local, las alternativas de expansión a mercados de la región, la implementación de estándares internacionales en su cadena productiva y de comercialización serán la base para concretar el desarrollo, con todo ello se impulsará la intervención de sus principales actores, normalizando y regulando la operación de productores informales con el fin de incorporarlos a una propuesta de desarrollo conjunta de la regiónThe objective of this research is to develop a strategic planning that allows the livestock sector in the Cajamarca region move from a current state to a desired future state, its development this based considering its livestock potential, existing market conditions, in the availability of various resources in the region, as well as interest from the government in developing the sector. The development of the strategic plan has considered an internal and external analysis, it has identified a situational framework with which strategies that contribute to achieving short-term and long-term focused primarily on the development of the sector. It should be noted that the current situation of the sector presents complex situations such as the fact that livestock production is atomized, in addition to the strong presence of contrary activities such as mining, however the potential and interest in developing the region as livestock area, It presents an opportunity that will achieve development and prosperity for the different stakeholders. Finally, the situation is favorable for the implementation of measures to boost the sector's development, improved production processes, its position in the local market, alternative expansion to markets in the region, the implementation of standards international in their production and marketing chain will be the basis for concrete development, with all the intervention of the main actors it will be promoted, standardizing and regulating the operation of informal producers in order to incorporate them into a development proposal jointly in the regionTesi

    Mast Cell Changes the Phenotype of Microglia via Histamine and ATP

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    Background/Aims: Microglia are the dynamic motile phagocytes of the brain considered the first line of defense against threats or disturbances to the Central Nervous System (CNS). Microglia help orchestrate the immunological response by interacting with others immune cells. Mast cells (MCs) are effector cells of the innate immune system distributed in all organs and vascularized tissues, brain included. Several molecular mechanisms for potential interactions between MCs and microglia have been determined. However, the effect of MCs on regulated exocytosis and phagocytic clearance in microglia has not been explored. Methods: Cocktails of MCs mediators (MCM) obtained at 37°C and 53°C were used to induce microglia activation. Changes in intracellular calcium [Ca2+]i and ATP release were studied by calcium and quinacrine fluorescence imaging. Fluorescent latex beads were used to assay phagocytosis in microglia after MCM treatment and compared to that measured in the presence of histamine, ATP and lipopolysaccharide (LPS). Iba-1 expression and area were quantified by immunofluorescence and histamine levels evaluated by ELISA techniques. Results: Local application onto microglia of the MC mediator cocktail elicited Ca2+ transients and exocytotic release associated with quinacrine dye de-staining. Ca2+ signals were mimicked by histamine and blocked by the H1 receptor (H1R) antagonist, cetirizine. Hydrolysis of ATP by apyrase also affected Ca2+ transients to a lesser extent. Iba-1 fluorescence, cell area and phagocytosis were enhanced by histamine through H1R. However, ATP prevented iba-1 expression and microglial phagocytosis. MCM showed combined effects of histamine and ATP, increasing the number of internalized microbeads per cell and area without raising iba1 expression. Conclusion: Our results highlight the relevance of MC-derived histamine and ATP in the modulation of secretory and phagocytic activities that would explain the heterogeneity of microglial responses in different pathological contexts.Agencia Estatal de Investigación/ProyectoJunta de Andalucí

    Associations of dietary energy density with body composition and cardiometabolic risk in children with overweight and obesity: role of energy density calculations, under-reporting energy intake and physical activity

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    This study examined (1) the association of dietary energy density from solid (EDS) and solid plus liquids (EDSL) with adiposity and cardiometabolic risk factors (CRF) in children with overweight and obesity, (2) the effect of under-reporting on the mentioned associations and (3) whether the association between ED and body composition and CRF is influenced by levels of physical activity. In a cross-sectional design, 208 overweight and obese children (8-12-year-old; 111 boys) completed two non-consecutive 24 h recalls. ED was calculated using two different approaches: EDS and EDSL. Under-reporters were determined with the Goldberg method. Body composition, anthropometry and fasting blood sample measurements were performed. Moderate to vigorous physical activity (MVPA) was registered with accelerometers (7-d-register). Linear regressions were performed to evaluate the association of ED with the previously mentioned variables. Neither EDS nor EDSL were associated with body composition or CRF. However, when under-reporters were excluded, EDS was positively associated with BMI (P=0 019), body fat percentage (P=0 005), abdominal fat (P=0 008) and fat mass index (P=0 018), while EDSL was positively associated with body fat percentage (P=0 008) and fat mass index (P=0 026). When stratifying the group according to physical activity recommendations, the aforementioned associations were only maintained for non-compliers. Cluster analysis showed that the low-ED and high-MVPA group presented the healthiest profile for all adiposity and CRF. These findings could partly explain inconsistencies in literature, as we found that different ED calculations entail distinct results. Physical activity levels and excluding under-reporters greatly influence the associations between ED and adiposity in children with overweight and obesity.The research leading to these results has received funding from la Caixa Foundation and Triptolemos Foundation, the Ministry of Health (FIS PI081297), the Research Network on Preventative Activities and Health Promotion (RD06/0018/ 0038), the Henning and Johan Throne-Holst Foundation (F. B. O.), the Spanish Ministry of Education, Culture and Sport (FPU14/03329 to M. M.), the Spanish Ministry of Economy and Competitiveness (DEP2013-47540 and DEP2016-78377-R; BES-2014-068829 to C. C.-S.), Fondo de Investigacion Sanitaria del Instituto de Salud Carlos III (PI13/01335), Fondos Estructurales de la Union Europea (FEDER), Una manera de hacer Europa, the Spanish Ministry of Science and Innovation (RYC-2011-09011 to F. B. O.), the University of Granada, Plan Propio de Investigacion 2016, Excellence Actions: Units of Excellence, Unit of Excellence on Exercise and Health (UCEES), Programa de Captacion de Talento - UGR Fellows (L. G.-M.), the SAMID III network, RETICS (PN I +D+ I 2017-2021). This study has been partially funded by the University of Granada, Plan Propio de Investigacion 2016, Excellence actions: Units of Excellence; Unit of Excellence on Exercise and Health (UCEES), and by the Junta de Andalucia, Consejeria de Conocimiento, Investigacion y Universidades and European Regional Development Fund (ERDF), reference SOMM17/6107/UGR. ISCIII-Sub-Directorate General for Research Assessment and Promotion, the European Regional Development Fund (RD16/ 0022), the EXERNET Research Network on Exercise and Health in Special Populations (DEP2005-00046/ACTI), and the University of the Basque Country (GIU14/21). J. M.-G. is supported by the Spanish Ministry of Education, Culture and Sport (FPU14/06837). J. H. M. is supported by the Spanish Ministry of Education, Culture and Sport (FPU15/02645)
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