2,313 research outputs found
The ability of fifth grade children to discriminate between fact and opinion statement
Thesis (Ed.M.)--Boston Universit
EFFICACY TEST PROTOCOLS FOR EVALUATION OF ULTRASONIC RODENT REPELLENT DEVICES
Controlled laboratory and field test protocols were developed to assess the repellent efficacies of six commercially manufactured ultrasonic rodent repellent devices. The laboratory test structure (68.7 sq m) was divided into two rooms (32.5 sq m each) with a central harborage area (3.5 sq m) containing a colony of 12 wild Norway rats (Rattus norvegicus). For each test, a single ultrasonic device was attached to the far end of one room and rat activity measures (oat consumption, packet damage, photocell counts) were taken during 1-week baseline and 2-1/2-week test periods. Field test structures varied in floor area (6.5 to 197 sq m) and were of either metal or wood construction. All contained existing Norway rat, house mouse (Mus musculus), or field mouse (Peromyscus maniculatus) infestations. No rodent control was conducted at these sites other than the application of selected ultrasonic devices. Rodent activity (packet damage, food consumption, rodent tracks) was measured twice per week during three successive 3-week intervals with devices operating only during the second interval. Repeated measures analysis of variance and chi square were used to statistically evaluate the reliability of ultrasound effects
Fluticasone/salmeterol reduces remodelling and neutrophilic inflammation in severe equine asthma
Broadband quadrature-squeezed vacuum and nonclassical photon number correlations from a nanophotonic device
We report the first demonstrations of both quadrature squeezed vacuum and
photon number difference squeezing generated in an integrated nanophotonic
device. Squeezed light is generated via strongly driven spontaneous four-wave
mixing below threshold in silicon nitride microring resonators. The generated
light is characterized with both homodyne detection and direct measurements of
photon statistics using photon number-resolving transition edge sensors. We
measure ~dB of broadband quadrature squeezing (~dB inferred
on-chip) and ~dB of photon number difference squeezing (~dB
inferred on-chip). Nearly-single temporal mode operation is achieved, with raw
unheralded second-order correlations as high as measured
(~when corrected for noise). Multi-photon events of over 10 photons
are directly detected with rates exceeding any previous quantum optical
demonstration using integrated nanophotonics. These results will have an
enabling impact on scaling continuous variable quantum technology.Comment: Significant improvements and updates to photon number squeezing
results and discussions, including results on single temporal mode operatio
Two-dimensional electron gas formation in undoped In[0.75]Ga[0.25]As/In[0.75]Al[0.25]As quantum wells
We report on the achievement of a two-dimensional electron gas in completely
undoped In[0.75]Al[0.25]As/In[0.75]Ga[0.25]As metamorphic quantum wells. Using
these structures we were able to reduce the carrier density, with respect to
reported values in similar modulation-doped structures. We found experimentally
that the electronic charge in the quantum well is likely due to a deep-level
donor state in the In[0.75]Al[0.25]As barrier band gap, whose energy lies
within the In[0.75]Ga[0.25]As/In[0.75]Al[0.25]As conduction band discontinuity.
This result is further confirmed through a Poisson-Schroedinger simulation of
the two-dimensional electron gas structure.Comment: 17 pages, 6 figures, to be published in J. Vac. Sci. Technol.
Single pulse sampling valve measurements of wall layer hydrocarbons in a combustion bomb
The processes occurring during head-on flame quench at a cold combustion chamber wall have been studied in a cylindrical combustion bomb. Gas samples were withdrawn from the wall layer using an electrohydraulic sampling valve and were analyzed by gas chromatography. Propane was used as fuel and the experiments were performed at fuel lean ([Phi] = 0.9) conditions. The results indicate that hydrocarbons present in the quench layer are substantially oxidized within 4 ms of flame arrival.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25329/1/0000774.pd
Review of existing numerical methods and validation procedure available for bird strike modelling
Summary This paper reviews numerical methods that are currently available to simulate bird strike as well as the theory of the event. It also summarizes important parameters and provides guidelines as to how to set up the analysis and how to evaluate a model. The information provided is based on physical properties and available results regarding a bird and its behaviour upon impact. The simulations have been performed with LS-DYNA 970 but can be done in similar dynamic finite elements analysis codes
Comparative hydrolysis of P2 receptor agonists by NTPDases 1, 2, 3 and 8
Nucleoside triphosphate diphosphohydrolases 1, 2, 3 and 8 (NTPDases 1, 2, 3 and 8) are the dominant ectonucleotidases and thereby expected to play important roles in nucleotide signaling. Distinct biochemical characteristics of individual NTPDases should allow them to regulate P2 receptor activation differentially. Therefore, the biochemical and kinetic properties of these enzymes were compared. NTPDases 1, 2, 3 and 8 efficiently hydrolyzed ATP and UTP with Km values in the micromolar range, indicating that they should terminate the effects exerted by these nucleotide agonists at P2X1- and P2Y2,4,11 receptors. Since NTPDase1 does not allow accumulation of ADP, it should terminate the activation of P2Y1,12,13 receptors far more efficiently than the other NTPDases. In contrast, NTPDases 2, 3 and 8 are expected to promote the activation of ADP specific receptors, because in the presence of ATP they produce a sustained (NTPDase2) or transient (NTPDases 3 and 8) accumulation of ADP. Interestingly, all plasma membrane NTPDases dephosphorylate UTP with a significant accumulation of UDP, favoring P2Y6 receptor activation. NTPDases differ in divalent cation and pH dependence, although all are active in the pH range of 7.0-.5. Various NTPDases may also distinctly affect formation of extracellular adenosine and therefore adenosine receptor-mediated responses, since they generate different amounts of the substrate (AMP) and inhibitor (ADP) of ecto-5-nucleotidase, the rate limiting enzyme in the production of adenosine. Taken together, these data indicate that plasma membrane NTPDases hydrolyze nucleotides in a distinctive manner and may therefore differentially regulate P2 and adenosine receptor signaling
Morphological Variation Among Herring Gulls (Larus Argentatus) And Great Black-Backed Gulls (Larus Marinus) In Eastern North America
Herring Gull (Larus argentatus) and Great Black-backed Gull (L. marinus) morphometric data from various eastern North American locations was collected to examine the sources of variation in body size within and among geographic regions. For Herring Gulls, significant differences in all commonly taken measurements at local and regional scales were found. However, most of the variation in measurements was due to sex differences and the natural variance seen within local populations. Herring Gulls breeding in the Arctic did not show any evidence of being morphologically different from other groups. A discriminant function derived from a Newfoundland, Canada, breeding population of Herring Gulls successfully assigned the sex of birds in Atlantic Canada and Nunavut, Canada, further emphasizing that most of the variation seen is between sexes and not among local or even regional populations. It also indicates that the evitable variation introduced by inter-individual differences in measurements was insufficient to compromise the utility of the discriminant function. The correct classification rate was lower for Great Lakes breeding Herring Gulls, indicating that these birds have different morphologies than those of populations in easterly regions. In contrast, few differences and no clear geographic patterns were found in measurements for Great Black-backed Gulls. These results were consistent with recent genetic information, suggesting an older west to east radiation of Herring Gulls across North America and a lack of isolation among Great Black-Backed Gull populations
Combined Effects of Acute Temperature Change and Elevated pCO2 on the Metabolic Rates and Hypoxia Tolerances of Clearnose Skate (Rostaraja eglanteria), Summer Flounder (Paralichthys dentatus), and Thorny Skate (Amblyraja radiata)
Understanding how rising temperatures, ocean acidification, and hypoxia affect the performance of coastal fishes is essential to predicting species-specific responses to climate change. Although a population’s habitat influences physiological performance, little work has explicitly examined the multi-stressor responses of species from habitats differing in natural variability. Here, clearnose skate (Rostaraja eglanteria) and summer flounder (Paralichthys dentatus) from mid-Atlantic estuaries, and thorny skate (Amblyraja radiata) from the Gulf of Maine, were acutely exposed to current and projected temperatures (20, 24, or 28 °C; 22 or 30 °C; and 9, 13, or 15 °C, respectively) and acidification conditions (pH 7.8 or 7.4). We tested metabolic rates and hypoxia tolerance using intermittent-flow respirometry. All three species exhibited increases in standard metabolic rate under an 8 °C temperature increase (Q10 of 1.71, 1.07, and 2.56, respectively), although this was most pronounced in the thorny skate. At the lowest test temperature and under the low pH treatment, all three species exhibited significant increases in standard metabolic rate (44–105%; p \u3c 0.05) and decreases in hypoxia tolerance (60–84% increases in critical oxygen pressure; p \u3c 0.05). This study demonstrates the interactive effects of increasing temperature and changing ocean carbonate chemistry are species-specific, the implications of which should be considered within the context of habitat.
Associated dataset:
Gail D. Schweiterman, Daniel P. Crear et al. 2019. Metabolic Rates and Hypoxia Tolerences of clearnose skate (Rostaraja eglanteria), summer flounder (Paralichthys dentatus), and thorny skate (Amblyraja radiata)
https://doi.org/10.25773/qmew-c18
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