1,264 research outputs found

    MAPM: A coherent dual CO2 laser DIAL system

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    The Mobile Atmospheric Pollutant Mapping System (MAPM) is a dual CO2 laser DIAL system with heterodyne detection that is being developed for large distance range resolved measurement of organic solvent vapors and aerosol clouds. The components have been chosen to allow measurements to be made to distances of 6 to 7 km in a period of 20 to 30 s. The major components of the system are listed. MAPM is being integrated into a system and will be tested with several organic solvent gases and vapors in a remotely positioned sample chamber and with a free release of ethylene. Experimental results and system performance are discussed

    CAUGHT BETWEEN A ROCK AND A HARD MINERAL ENCRUSTATION: LONG-LIVED AQUATIC INSECTS ACCUMULATE CALCIUM CARBONATE DEPOSITS IN A MONTANE DESERT STREAM

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    Aquatic ecosystems overlying regions of limestone bedrock can feature active deposition of calcium carbonate in the form of travertine or tufa. Although most travertine deposits form a cement-like layer on stream substrates, mineral deposits can also form on benthic invertebrates. However, little is known about which taxa may be prone to calcium carbonate encrustation and which life history traits may make taxa more susceptible to becoming encrusted. Here we report the presence of calcium carbonate deposits on live insects collected from a montane stream in the Madrean Sky Islands (Huachuca Mountains) of Arizona between 2011 and 2013. Life history differences are examined between taxa with and without travertine deposits. Thirteen genera of aquatic insects were found with calcium carbonate deposits on the exoskeleton as well as 22 other genera, also encountered in the study stream, that have not previously been found with such deposits. Taxa with calcium carbonate encrustation had significantly longer-lived aquatic stages than those without encrustation. Furthermore, encrustation presence did not differ among aerial dispersal modes. These results suggest that the extent of calcium carbonate deposition on aquatic insects is primarily related to the length of time they are in the stream. Since mineral encrustation may reduce predation pressure and mobility, changes in patterns of travertine formation in these systems may have profound effects on ecological interactions. Los ecosistemas dulceacuícolas ubicados en regiones de roca caliza pueden contener depósitos de carbonato de calcio en forma de travertino o tufa. Aunque muchos depósitos de travertino se encuentran como una capa o manto de cemento sobre el fondo del arroyo, los depósitos también pueden formarse sobre los invertebrados bentónicos. Sin embargo, poco se sabe acerca de las especies que son propensas a los depósitos de travertino, o acerca de las características de estas especies que influyen en tal proceso. En este manuscrito reportamos la presencia de depósitos de travertino en insectos vivos y recolectados en un arroyo montañoso en el Archipiélago Madrense de Arizona durante 2011–2013 y examinamos las diferencias en las historias de vida entre taxones con o sin depósitos de travertino. Encontramos trece géneros de insectos acuáticos con travertino sobre el exoesqueleto y vientedos géneros sin travertino. Los taxones con travertino tienen una fase acuática significativamente más larga que los taxones sin travertino. Además, la presencia de travertino no difirió entre especies con distintas maneras de dispersión aérea. Estos resultados sugieren que las diferencias en los depósitos de travertino en insectos acuáticos ocurren principalmente a causa de la duración del período de vida acuática del insecto. Aunque los depósitos de travertino pueden reducir la presión por depredación y movilidad, cambios en los patrones de formación de travertino en estos sistemas pueden afectar profundamente las interacciones ecológicas

    Enhanced charge detection of spin qubit readout via an intermediate state

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    We employ an intermediate excited charge state of a lateral quantum dot device to increase the charge detection contrast during the qubit state readout procedure, allowing us to increase the visibility of coherent qubit oscillations. This approach amplifies the coherent oscillation magnitude but has no effect on the detector noise resulting in an increase in the signal to noise ratio. In this letter we apply this scheme to demonstrate a significant enhancement of the fringe contrast of coherent Landau-Zener-Stuckleberg oscillations between singlet S and triplet T+ two-spin states.Comment: 3 pages, 3 figure

    Team Gender Diversity and Investment Decision Making Behavior

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    We investigate whether the gender composition of a fund management team influences investment decision making behavior. Using an experimental economics approach, we examine the relationship between gender diversity and investment decisions. We find evidence that a male presence increases the probability of selecting a higher risk investment. However, the all male teams are not the most risk seeking. Moreover, having a male presence can increase loss aversion. In the context of workforce composition, these results could have important implications for team investment decisions driven by the assessment of risk and return trade-offs. (JEL: G11

    Chronic Administration of a Leupeptin-Derived Calpain Inhibitor Fails to Ameliorate Severe Muscle Pathology in a Canine Model of Duchenne Muscular Dystrophy

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    Calpains likely play a role in the pathogenesis of Duchenne muscular dystrophy (DMD). Accordingly, calpain inhibition may provide therapeutic benefit to DMD patients. In the present study, we sought to measure benefit from administration of a novel calpain inhibitor, C101, in a canine muscular dystrophy model. Specifically, we tested the hypothesis that treatment with C101 mitigates progressive weakness and severe muscle pathology observed in young dogs with golden retriever muscular dystrophy (GRMD). Young (6-week-old) GRMD dogs were treated daily with either C101 (17 mg/kg twice daily oral dose, n = 9) or placebo (vehicle only, n = 7) for 8 weeks. A battery of functional tests, including tibiotarsal joint angle, muscle/fat composition, and pelvic limb muscle strength were performed at baseline and every 2 weeks during the 8-week study. Results indicate that C101-treated GRMD dogs maintained strength in their cranial pelvic limb muscles (tibiotarsal flexors) while placebo-treated dogs progressively lost strength. However, concomitant improvement was not observed in posterior pelvic limb muscles (tibiotarsal extensors). C101 treatment did not mitigate force drop following repeated eccentric contractions and no improvement was seen in the development of joint contractures, lean muscle mass, or muscle histopathology. Taken together, these data do not support the hypothesis that treatment with C101 mitigates progressive weakness or ameliorates severe muscle pathology observed in young dogs with GRMD

    Comparison of EMP and HERO programs

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    Because of the unique features of electromagnetic pulse (EMP) and Hazardous Electromagnetic Effects on Ordnance (HERO), much research and money has gone into protecting weapon systems and ordnance against it. The EMP and HERO phenomena do have a variety of differences and require differences of hardening technique to protect against it. However, they both involve radiation effects and can prematurely initiate ordnance via the electroexplosive device (EED). Protection of weapon systems and ordnance against electronic damage and upset plus EED initiation takes on more of an art form rather than science once basic principles are applied. Nevertheless by relating these two programs via the initiating temperature of the EED. they can be accurately compared with each other. Because of this observation, the two programs can be effectively combined to work jointly on ordnance hardening and protection including all forms of radiation type hazards, present and future.http://archive.org/details/comparisonofemph00bogaLieutenant. United States NavyApproved for public release; distribution is unlimited
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