13,432 research outputs found

    A Unified Model For Developmental Robotics

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    We present the architecture and distributed algorithms of an implemented system called NeuSter, that unifies learning, perception and action for autonomous robot control. NeuSter comprises several sub-systems that provide online learning for networks of million neurons on machine clusters. It extracts information from sensors, builds its own representations of the environment in order to learn non-predefined goals

    The Role Of Stakeholders On Implementing Universal Services In Vietnam

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    This paper examines the role of stakeholders on implementing the universal services policy in Vietnam (interval 2005-2010) in order to clarify their impact and their position on performing the policy. The stakeholder theory is employed to identify and categorize the stakeholders. The authors are to look at the role of the stakeholders such as the national government, international organizations, policy intermediaries, companies, and customers/citizens via applying the qualitative method to gather data and analyse the secondary document. The qualitative approach of interviews on some officers who participated in building up and operating the policy was also conducted. The results demonstrate that stakeholders have a huge impact on the success of the universal service policy

    Near-Infrared Variability Study of the Central 2.3 arcmin x 2.3 arcmin of the Galactic Centre II. Identification of RR Lyrae Stars in the Milky Way Nuclear Star Cluster

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    Because of strong and spatially highly variable interstellar extinction and extreme source crowding, the faint (K>15) stellar population in the Milky Way's nuclear cluster is still poorly studied. RR Lyrae stars provide us with a tool to estimate the mass of the oldest, relative dim stellar population. Recently, we analyzed HST/WFC3/IR observations of the central 2.3'x2.3' of the Milky Way and found 21 variable stars with periods between 0.2 and 1d. Here, we present a further comprehensive analysis of these stars. The period-luminosity relationship of RR Lyrae is used to derive their extinctions and distances. Using multiple approaches, we classify our sample as four RRc, four RRab and three candidates, ten binaries. Especially, the four RRabs show sawtooth light curves and fall exactly onto the Oosterhoff I division in the Bailey diagram. Compared to the RRabs reported by Minniti et al, 2016, our new RRabs have higher extinction (A_K>1.8) and should be closer to the Galactic Centre. The extinction and distance of one RRab match those for the nuclear star cluster given in previous works. We perform simulations and find that after correcting for incompleteness, there could be no more than 40 RRabs within the nuclear star cluster and in our field-of-view. Through comparing with the known globular clusters of the Milky Way, we estimate that if there exists an old, metal-poor (-1.5<[Fe/H]<-1) stellar population in the Milky Way nuclear star cluster on a scale of 5x5pc, then it contributes at most 4.7x10^5 solar mass, i.e., ~18% of the stellar mass.Comment: 33 pages, 10 figures. The paper has been accepted to be published in MNRA

    Widespread association between the ericoid mycorrhizal fungus Rhizoscyphus ericae and a leafy liverwort in the maritime and sub-Antarctic

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    A recent study identified a fungal isolate from the Antarctic leafy liverwort Cephaloziella varians as the ericoid mycorrhizal associate Rhizoscyphus ericae. However, nothing is known about the wider Antarctic distribution of R. ericae in C. varians, and inoculation experiments confirming the ability of the fungus to form coils in the liverwort are lacking. Using direct isolation and baiting with Vaccinium macrocarpon seedlings, fungi were isolated from C. varians sampled from eight sites across a 1875-km transect through sub- and maritime Antarctica. The ability of an isolate to form coils in aseptically grown C. varians was also tested. Fungi with 98–99% sequence identity to R. ericae internal transcribed spacer (ITS) region and partial large subunit ribosomal (r)DNA sequences were frequently isolated from C. varians at all sites sampled. The EF4/Fung5 primer set did not amplify small subunit rDNA from three of five R. ericae isolates, probably accounting for the reported absence of the fungus from C. varians in a previous study. Rhizoscyphus ericae was found to colonize aseptically-grown C. varians intracellularly, forming hyphal coils. This study shows that the association between R. ericae and C. varians is apparently widespread in Antarctica, and confirms that R. ericae is at least in part responsible for the formation of the coils observed in rhizoids of field-collected C. varians

    Near-Infrared Variability Study of the Central 2.3 arcmin x 2.3 arcmin of the Galactic Centre I. Catalog of Variable Sources

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    We used four-year baseline HST/WFC3 IR observations of the Galactic Centre in the F153M band (1.53 micron) to identify variable stars in the central ~2.3'x2.3' field. We classified 3845 long-term (periods from months to years) and 76 short-term (periods of a few days or less) variables among a total sample of 33070 stars. For 36 of the latter ones, we also derived their periods (<3 days). Our catalog not only confirms bright long period variables and massive eclipsing binaries identified in previous works, but also contains many newly recognized dim variable stars. For example, we found \delta Scuti and RR Lyrae stars towards the Galactic Centre for the first time, as well as one BL Her star (period < 1.3 d). We cross-correlated our catalog with previous spectroscopic studies and found that 319 variables have well-defined stellar types, such as Wolf-Rayet, OB main sequence, supergiants and asymptotic giant branch stars. We used colours and magnitudes to infer the probable variable types for those stars without accurately measured periods or spectroscopic information. We conclude that the majority of unclassified variables could potentially be eclipsing/ellipsoidal binaries and Type II Cepheids. Our source catalog will be valuable for future studies aimed at constraining the distance, star formation history and massive binary fraction of the Milky Way nuclear star cluster.Comment: has been accepted to be published in MNRAS, 64 pages, 26 figures. The complete lists of table 3, 4, 8 and 9 will be published onlin

    Implantation of a three-dimensional fibroblast matrix improves left ventricular function and blood flow after acute myocardial infarction

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    This study was designed to determine if a viable biodegradable three-dimensional fibroblast construct (3DFC) patch implanted on the left ventricle after myocardial infarction (MI) improves left ventricular (LV) function and blood flow. We ligated the left coronary artery of adult male Sprague-Dawley rats and implanted the 3DFC at the time of the infarct. Three weeks after MI, the 3DFC improved LV systolic function by increasing (p < 0.05) ejection fraction (37 +/- 3% to 62 +/- 5%), increasing regional systolic displacement of the infarcted wall (0.04 +/- 0.02 to 0.11 +/- 0.03 cm), and shifting the passive LV diastolic pressure volume relationship toward the pressure axis. The 3FDC improved LV remodeling by decreasing (p < 0.05) LV end-systolic and end-diastolic diameters with no change in LV systolic pressure. The 3DFC did not change LV end-diastolic pressure (LV EDP; 25 +/- 2 vs. 23 +/- 2 mmHg) but the addition of captopril (2mg/L drinking water) lowered (p < 0.05) LV EDP to 12.9 +/- 2.5 mmHg and shifted the pressure-volume relationship toward the pressure axis and decreased (p < 0.05) the LV operating end-diastolic volume from 0.49 +/- 0.02 to 0.34 +/- 0.03 ml. The 3DFC increased myocardial blood flow to the infarcted anterior wall after MI over threefold (p < 0.05). This biodegradable 3DFC patch improves LV function and myocardial blood flow 3 weeks after MI. This is a potentially new approach to cell-based therapy for heart failure after MI

    Identification of causes of postharvest carrot losses in the retail market

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    As perdas pós-colheita de cenoura em 4 lojas de uma rede de supermercados de Brasília foram avaliadas pelo período de um ano. A amostragem foi realizada em duas etapas: antes da exposição do produto na área de vendas (amostra Qualidade Inicial) e após o descarte das perdas do produto (amostra Descarte). Foram quantificadas a proporção de raízes pequenas, médias e grandes e a incidência dos danos: bifurcação, rachadura, defeitos de formato, doença, praga, dano mecânico e outros. A cenoura comprada pelo supermercado apresentou cerca de 86,88 + 0,66% das raízes na faixa de 12-22 cm. No descarte, diminuiu a proporção de cenouras médias e grandes, enquanto aumentou a proporção de cenouras pequenas e quebradas. A proporção de raízes com ombro verde foi reduzida de 23,74 + 1,11% na amostra Qualidade Inicial para 13,29 + 1,37% na amostra Descarte, indicando que grande parte das raízes com ombro verde foi adquirida pelo consumidor, e neste caso não parece ter sido um fator indutor de perda. Cerca de 51% das cenouras recebidas no supermercado apresentavam algum tipo de dano, sendo os mais importantes defeitos de formato (31,0 + 1,16%), dano mecânico (9,46 + 0,4%) e murcha (4,66 + 0,99%). As principais causas de descarte foram dano mecânico (37,4 + 2,47%), defeitos de formato (32,0 + 2,58%) e murcha (7,6 + 1,59%). _________________________________________________________________________________ ABSTRACTCarrot post-harvest losses were evaluated for one year in four stores of a supermarket chain in Brasilia, Brazil. Sampling was performed at two stages: at reception in the store and after exclusion or removal from retail displays. The proportion of large, middle, small and broken roots was measured. Damaged roots were classified in one of the following categories and measured: splitting, forking, mishaped roots, pathological breakdown, pest damage, mechanical damage, and unidentified damage. About 86,88 + 0,66% of the roots were 12-22 cm long (middle size). Wastage presented a higher proportion of small and broken roots and a lower proportion of middle and large roots. The incidence of green top in waste decreased, when compared to the sample taken before marketing, from 23,74 + 1,11% to 13,29 + 1,37%. This is an indication that a substantial proportion of roots with green tops were sold and therefore this defect do not seem to be a factor inducing loss. About 51% of the roots delivered at the supermarket were damaged and the most important defects were mishaped roots (31,0 + 1,16%), mechanical damage (9,46 + 0,4%), and wilting (4,66 + 0,99%). The main causes of waste were mechanical damage (37,4 + 2,47%), mishaped roots (32,0 + 2,58%) and wilting (7,6 + 1,59%)

    Can the Prechtl method for the qualitative assessment of general movements be used to predict neurodevelopmental outcome, at eighteen months to three years, of infants born preterm?

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    Background: Preterm infants are more at risk of atypical neurodevelopment and diagnosis of impairment often occurs later in life. The Prechtl method for the qualitative assessment of general movements has been found to predict neurodevelopmental outcome in full term infants. Despite this, it is not clear whether the Prechtl assessment is predictive of neurodevelopmental outcome when used for preterm infants. Objectives: To review the literature regarding the use of the Prechtl method for the qualitative assessment of general movements in predicting neurodevelopmental outcome, at eighteen months to three years, of infants born preterm. Methods: A systematic search of MEDLINE, CINAHL, Science Citation Index, PsycINFO, Science Direct, Scopus, Social Sciences Index, Education Source, ERIC, SPORTDiscus, SciELO and SocINDEX was conducted in November 2015. The methodological quality of the included studies was critically appraised using a modified version of the Downs and Black quality index. Results: Five articles met the inclusion criteria. The Prechtl method of assessment was found to be predictive of both neuromotor and cognitive impairments at eighteen months to three years. The writhing period was found to have higher sensitivity but lower specificity and correlation to neurodevelopmental outcomes compared to the fidgety period. Combining both periods of assessment led to higher predictive power. The assessment was also found to be more predictive of severe impairment as opposed to minor impairment. Conclusions: The results of this systematic review suggest that Prechtl method of assessment can be used to predict neurodevelopmental outcome in preterm infants
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