3,301 research outputs found

    Thinking Adaptive: Towards a Behaviours Virtual

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    In this paper we name some of the advantages of virtual laboratories; and propose that a Behaviours Virtual Laboratory should be useful for both biologists and AI researchers, offering a new perspective for understanding adaptive behaviour. We present our development of a Behaviours Virtual Laboratory, which at this stage is focused in action selection, and show some experiments to illustrate the properties of our proposal, which can be accessed via Internet

    Role of Galaxy Mergers in Cosmic Star Formation History

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    We present a morphology study of intermediate-redshift (0.2<z<1.2) luminous infrared galaxies (LIRGs) and general field galaxies in the GOODS fields using a revised asymmetry measurement method optimized for deep fields. By taking careful account of the importance of the underlying sky-background structures, our new method does not suffer from systematic bias and offers small uncertainties. By redshifting local LIRGs and low-redshift GOODS galaxies to different higher redshifts, we have found that the redshift dependence of the galaxy asymmetry due to surface-brightness dimming is a function of the asymmetry itself, with larger corrections for more asymmetric objects. By applying redshift-, IR-luminosity- and optical-brightness-dependent asymmetry corrections, we have found that intermediate-redshift LIRGs generally show highly asymmetric morphologies, with implied merger fractions ~50% up to z=1.2, although they are slightly more symmetric than local LIRGs. For general field galaxies, we find an almost constant relatively high merger fraction (20-30%). The B-band LFs of galaxy mergers are derived at different redshifts up to z=1.2 and confirm the weak evolution of the merger fraction after breaking the luminosity-density degeneracy. The IR luminosity functions (LFs) of galaxy mergers are also derived, indicating a larger merger fraction at higher IR luminosity. The integral of the merger IR LFs indicates a dramatic evolution of the merger-induced IR energy density [(1+z)^(5-6)}], and that galaxy mergers start to dominate the cosmic IR energy density at z>~1.Comment: Accepted for publication in ApJ, 25 pages, 23 figures (2 colors). The high-resolution pdf is at http://cztsy.as.arizona.edu/~yong/Research/SHI_MERGER.pd

    Star Formation in a Stellar Mass Selected Sample of Galaxies to z=3 from the GOODS NICMOS Survey (GNS)

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    We present a study of the star-forming properties of a stellar mass-selected sample of galaxies in the GOODS NICMOS Survey (GNS), based on deep Hubble Space Telescope imaging of the GOODS North and South fields. Using a stellar mass selected sample, combined with HST/ACS and Spitzer data to measure both UV and infrared derived star formation rates (SFR), we investigate the star forming properties of a complete sample of ~1300 galaxies down to log M*=9.5 at redshifts 1.5<z<3. Eight percent of the sample is made up of massive galaxies with M*>10^11 Msun. We derive optical colours, dust extinctions, and ultraviolet and infrared SFR to determine how the star formation rate changes as a function of both stellar mass and time. Our results show that SFR increases at higher stellar mass such that massive galaxies nearly double their stellar mass from star formation alone over the redshift range studied, but the average value of SFR for a given stellar mass remains constant over this 2 Gyr period. Furthermore, we find no strong evolution in the SFR for our sample as a function of mass over our redshift range of interest, in particular we do not find a decline in the SFR among massive galaxies, as is seen at z < 1. The most massive galaxies in our sample (log M*>11) have high average SFRs with values, SFR(UV,corr) = 103+/-75 Msun/yr, yet exhibit red rest-frame (U-B) colours at all redshifts. We conclude that the majority of these red high-redshift massive galaxies are red due to dust extinction. We find that A(2800) increases with stellar mass, and show that between 45% and 85% of massive galaxies harbour dusty star formation. These results show that even just a few Gyr after the first galaxies appear, there are strong relations between the global physical properties of galaxies, driven by stellar mass or another underlying feature of galaxies strongly related to the stellar mass.Comment: 18 pages, 10 figures, accepted for publication in MNRA

    Differential and Cultivar-Dependent Antioxidant Response of Whole and Fresh-Cut Carrots of Different Root Colors to Postharvest UV-C Radiation

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    Fresh-cut produce have become widely popular, increasing vegetable consumption in many parts of the word. However, they are more perishable than unprocessed fresh vegetables, requiring cold storage to preserve their quality and palatability. In addition to cold storage, UV radiation has been used experimentally to try to increase nutritional quality and postharvest shelf life, revealing increased antioxidant levels in some fruits and vegetables, including orange carrots. Carrot is one of the main whole and fresh-cut vegetables worldwide. In addition to orange carrots, other root color phenotypes (e.g., purple, yellow, red) are becoming increasingly popular in some markets. The effect of the UV radiation and cold storage has not been explored in these root phenotypes. This study investigated the effect of postharvest UV-C radiation in whole and fresh-cut (sliced and shredded) roots of two purple, one yellow, and one orange-rooted cultivar, with regard to changes in concentration of total phenolics (TP) and hydroxycinnamic acids (HA), chlorogenic acid (CGA), total and individual anthocyanins, antioxidant capacity (by DPPH and ABTS), and superficial color appearance, monitoring such changes during cold storage. Results revealed that the UV-C radiation, the fresh-cut processing, and the cold storage influenced the content of antioxidant compounds and activities to varying extents, depending on the carrot cultivar, the degree of processing, and the phytochemical compound analyzed. UV-C radiation increased antioxidant capacity up to 2.1, 3.8, 2.5-folds; TP up to 2.0, 2.2, and 2.1-folds; and CGA up to 3.2, 6.6, and 2.5-folds, relative to UV-C untreated controls, for orange, yellow, and purple carrots, respectively. Anthocyanin levels were not significantly modified by the UV-C in both purple carrots evaluated. A moderate increase in tissue browning was found in some fresh-cut processed UV-C treated samples of yellow and purple but not orange roots. These data suggest variable potential for increasing functional value by UV-C radiation in different carrot root colors.EEA La ConsultaFil: Valerga, Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Valerga, Lucia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Gonzalez, Roxana Elizabeth. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Gonzalez, Roxana Elizabeth. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Pérez, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pérez, María Belén. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Concellón, Analía. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Concellón, Analía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Concellón, Analía. Universidad Nacional de La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Concellón, Analía. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; ArgentinaFil: Cavagnaro, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Cavagnaro, Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria La Consulta; Argentina.Fil: Cavagnaro, Pablo. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; Argentin

    Current State of Teledentistry in Chile

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    Chile is a country where the geography and territorial distribution of the population make healthcare a constant challenge. Despite a reported improvement on oral health indicators, some levels of inequality are still noted in terms of access to healthcare services. In this context, teledentistry has been considered an effective tool to respond to the population’s healthcare needs. The aim of this paper is to present the current state of teledentistry in Chile. This paper describes the initiatives and programmes of teledentistry developed in Chile, the ethical and legal aspects, financing sources and pending challenges for its consolidation. It is expected that teledentistry will contribute toward an increase in coverage and access to specialists, improve the appropriateness of referrals and reduce costs of specialist care

    Economic scoring formulae in multi-Attribute construction auctions

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    Copyright © 2017 ISEC Press. Public tendering implies the free concurrence and competition of bidding companies that certify their solvency, so that those companies proposing the most attractive bid, both technically and economically, are awarded the contracts and carry them out according to the same terms and conditions that they proposed. Generally, there is high competition in public tendering, both concerning the number of bidders (constantly increasing), as well as the profit margin (constantly decreasing). On the other side, handling the procurement process, there is a contracting authority that spends public money while trying to fulfill a particular socio-economic objective. This paper will take the contracting authority's (auctioneer's) point of view which is in charge of devising and implementing the awarding criteria, as well as choosing the best bidder. Particularly, this paper will focus on some aspects of the Economic Scoring Formula (ESF) design. The ESF constitutes a set of mathematical expressions that transform the economic bids submitted by the bidders into scores, so that, eventually, the bidders can be ranked and the best one selected. We will conclude that, despite apparently simple, how ESF are configured eventually have profound consequences on bidding behavior and some bidding results, like a higher or lower bid dispersion
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