401 research outputs found

    Observations on the urban ecology of the Neotropical stingless bee Tetragonisca angustula (Hymenoptera: Apidae: Meliponini)

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    This is the publisher's version, also available electronically from https://journals.ku.edu/index.php/melittology/indexTetragonisca angustula (Latreille) is a small, docile, cavity-nestingstingless bee that is widely distributed in the Neotropical region. This speciesis particularly abundant in disturbed environments, including humansettlements. Between August 2005 and March 2006, we located and followed duringeight months 59 nests of this species in Medellín, the second most populatedcity in Colombia. Herein, we document their foraging behavior, mortality, andincidence of predators and natural enemies. Also, to determine if higherambient temperature and light intensity in urban environments affect the dailyforaging activity of T. angustula, wecompared the daily foraging activity of bees from nests found in open areas in thecity and bees from nests from a nearby covered, forested area. Likewise, todetermine if urban nests of T. angustulaare largely undetected and undisturbed by people, we experimentally made themvisible by adding a ring color (white, red, or black) around the nest entrance tube.Our observations indicate that higher ambient temperature and light intensity inurban environments do not significantly affect the daily foraging activity of T. angustula. Nearly half of the markednests disappeared, thus suggesting that nests of T. angustula are often undetected by people in Medellín. We discussbriefly some features of the biology of T.angustula that might contribute to its success in urban environments

    A new paracolletine bee from Colombia (Hymenoptera: Colletidae), with an updated checklist of the tropical Andean bee fauna

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    A new species of the paracolletine genus Lonchopria Vachal, Lonchopria (Biglossa) comforti Gonzalez & Engel, new species, from high elevations in the Central Andes of Colombia is described and figured.  A preliminary key to the species of the Lonchopria subgenus Biglossa Friese is presented.  Recent records of bees occurring at elevations above 2500 m in Colombia and other Andean countries are also summarized

    Acute Postoperative Infectious Endophthalmitis: Advances in Diagnosis and Treatment

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    Acute postoperative infectious endophthalmitis remains one of the most dreaded complications of ophthalmic surgery. One of the keys to success in treating this complication is to make an early clinical diagnosis and, if possible, an etiologic diagnosis that can guide treatment with antibiotic therapy. Different antibiotic therapy modalities have emerged over the years that have made it possible to treat even resistant strains of various microorganisms that cause endophthalmitis. Another relevant advance made in the etiological diagnosis of endophthalmitis is the advent of molecular biology techniques, such as the real-time polymerase chain reaction, which can detect minimal amounts of the genetic material of the causative microorganism present in the vitreous in a short period of time, thus improving treatment outcomes with better-guided therapy with intravitreal antibiotics. Aside from advances in postoperative diagnosis methods, the surgical treatment of endophthalmitis has had significant improvements in vitrectomy techniques, and in many cases, it has been proposed as the first-line treatment concomitantly with intravitreal antibiotic therapy. Moreover, there is increasing evidence that prophylaxis with intracameral antibiotic therapy further decreases postoperative endophthalmitis incidence

    The 2HWC HAWC Observatory Gamma Ray Catalog

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    We present the first catalog of TeV gamma-ray sources realized with the recently completed High Altitude Water Cherenkov Observatory (HAWC). It is the most sensitive wide field-of-view TeV telescope currently in operation, with a 1-year survey sensitivity of ~5-10% of the flux of the Crab Nebula. With an instantaneous field of view >1.5 sr and >90% duty cycle, it continuously surveys and monitors the sky for gamma ray energies between hundreds GeV and tens of TeV. HAWC is located in Mexico at a latitude of 19 degree North and was completed in March 2015. Here, we present the 2HWC catalog, which is the result of the first source search realized with the complete HAWC detector. Realized with 507 days of data and represents the most sensitive TeV survey to date for such a large fraction of the sky. A total of 39 sources were detected, with an expected contamination of 0.5 due to background fluctuation. Out of these sources, 16 are more than one degree away from any previously reported TeV source. The source list, including the position measurement, spectrum measurement, and uncertainties, is reported. Seven of the detected sources may be associated with pulsar wind nebulae, two with supernova remnants, two with blazars, and the remaining 23 have no firm identification yet.Comment: Submitted 2017/02/09 to the Astrophysical Journa

    On the Design of a Web-Based Decision Support System for Brain Tumour Diagnosis Using Distributed Agents

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    This paper introduces HealthAgents, an EC-funded research project to improve the classification of brain tumours through multi-agent decision support over a distributed network of local databases or Data Marts. HealthAgents will not only develop new pattern recognition methods for a distributed classification and analysis of in vivo MRS and ex vivo/in vitro HRMAS and DNA data, but also define a method to assess the quality and usability of a new candidate local database containing a set of new cases, based on a compatibility score

    The Sensitivity of HAWC to High-Mass Dark Matter Annihilations

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    The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.Comment: 15 pages, 4 figures, version to be published in PR

    The search for transient astrophysical neutrino emission with IceCube-DeepCore

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    We present the results of a search for astrophysical sources of brief transient neutrino emission using IceCube and DeepCore data acquired between 2012 May 15 and 2013 April 30. While the search methods employed in this analysis are similar to those used in previous IceCube point source searches, the data set being examined consists of a sample of predominantly sub-TeV muon-neutrinos from the Northern Sky (-5 degrees < delta < 90 degrees) obtained through a novel event selection method. This search represents a first attempt by IceCube to identify astrophysical neutrino sources in this relatively unexplored energy range. The reconstructed direction and time of arrival of neutrino events are used to search for any significant self-correlation in the data set. The data revealed no significant source of transient neutrino emission. This result has been used to construct limits at timescales ranging from roughly 1 s to 10 days for generic soft-spectra transients. We also present limits on a specific model of neutrino emission from soft jets in core-collapse supernovae
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