5,050 research outputs found
Automatic signal range selector for metering devices Patent
Voltage range selection apparatus for sensing and applying voltages to electronic instruments without loading signal sourc
Ninja data analysis with a detection pipeline based on the Hilbert-Huang Transform
The Ninja data analysis challenge allowed the study of the sensitivity of
data analysis pipelines to binary black hole numerical relativity waveforms in
simulated Gaussian noise at the design level of the LIGO observatory and the
VIRGO observatory. We analyzed NINJA data with a pipeline based on the Hilbert
Huang Transform, utilizing a detection stage and a characterization stage:
detection is performed by triggering on excess instantaneous power,
characterization is performed by displaying the kernel density enhanced (KD)
time-frequency trace of the signal. Using the simulated data based on the two
LIGO detectors, we were able to detect 77 signals out of 126 above SNR 5 in
coincidence, with 43 missed events characterized by signal to noise ratio SNR
less than 10. Characterization of the detected signals revealed the merger part
of the waveform in high time and frequency resolution, free from time-frequency
uncertainty. We estimated the timelag of the signals between the detectors
based on the optimal overlap of the individual KD time-frequency maps, yielding
estimates accurate within a fraction of a millisecond for half of the events. A
coherent addition of the data sets according to the estimated timelag
eventually was used in a characterization of the event.Comment: Accepted for publication in CQG, special issue NRDA proceedings 200
Study of Space Station propulsion system resupply and repair Final report
Resupply and repair capabilities for orbital space station bipropellant propulsion syste
Seasonal temperature acclimatization in a semi-fossorial mammal and the role of burrows as thermal refuges.
Small mammals in habitats with strong seasonal variation in the thermal environment often exhibit physiological and behavioral adaptations for coping with thermal extremes and reducing thermoregulatory costs. Burrows are especially important for providing thermal refuge when above-ground temperatures require high regulatory costs (e.g., water or energy) or exceed the physiological tolerances of an organism. Our objective was to explore the role of burrows as thermal refuges for a small endotherm, the pygmy rabbit (Brachylagus idahoensis), during the summer and winter by quantifying energetic costs associated with resting above and below ground. We used indirect calorimetry to determine the relationship between energy expenditure and ambient temperature over a range of temperatures that pygmy rabbits experience in their natural habitat. We also measured the temperature of above- and below-ground rest sites used by pygmy rabbits in eastern Idaho, USA, during summer and winter and estimated the seasonal thermoregulatory costs of resting in the two microsites. Although pygmy rabbits demonstrated seasonal physiological acclimatization, the burrow was an important thermal refuge, especially in winter. Thermoregulatory costs were lower inside the burrow than in above-ground rest sites for more than 50% of the winter season. In contrast, thermal heterogeneity provided by above-ground rest sites during summer reduced the role of burrows as a thermal refuge during all but the hottest periods of the afternoon. Our findings contribute to an understanding of the ecology of small mammals in seasonal environments and demonstrate the importance of burrows as thermal refuge for pygmy rabbits
Search for Gravitational Waves from Intermediate Mass Binary Black Holes
We present the results of a weakly modeled burst search for gravitational waves from mergers of non-spinning intermediate mass black holes (IMBH) in the total mass range 100-450 solar Mass and with the component mass ratios between 1:1 and 4:1. The search was conducted on data collected by the LIGO and Virgo detectors between November of 2005 and October of 2007. No plausible signals were observed by the search which constrains the astrophysical rates of the IMBH mergers as a function of the component masses. In the most efficiently detected bin centered on 88 + 88 solar Mass , for non-spinning sources, the rate density upper limit is 0.13 per Mpc(exp 3) per Myr at the 90% confidence level
Possibilities for Measurement and Compensation of Stray DC Electric Fields Acting on Drag-Free Test Masses
DC electric fields can combine with test mass charging and thermal dielectric
voltage noise to create significant force noise acting on the drag-free test
masses in the LISA (Laser Interferometer Space Antenna) gravitational wave
mission. This paper proposes a simple technique to measure and compensate
average stray DC potentials at the mV level, yielding substantial reduction in
this source of force noise. We discuss the attainable resolution for both
flight and ground based experiments.Comment: To be published in Advances in Space Research, COSPAR 2002 conference
proceedings (6 pages, 3 figures
Efficacy of Online Training for Improving Camp Staff Competency
Preparing competent staff is a critical issue within the camp community. This quasi-experimental study examined the effectiveness of an online course for improving staff competency in camp healthcare practices among college-aged camp staff and a comparison group (N = 55). We hypothesized that working in camp would increase competency test scores due to opportunities for staff to experientially apply knowledge learned online. Hierarchical linear modeling was used to analyse the cross-level effects of a between-individuals factor (assignment to experimental or comparison group) and within-individual effects of time (pre-test, post-test #1, and post-test #2) on online course test scores. At post-test #2, the difference in average test scores between groups was ~30 points, with the treatment group scoring lower on average than the comparison group. Factors that may have influenced these findings are explored, including fatigue and the limited durability of online learning. Recommendations for research and practice are discussed
Electron–nuclear double resonance on copper (II) tetraimidazole
We have investigated the electron–nuclear double resonance (ENDOR) from frozen aqueous solutions of 65Cu++(imidazole)4, 65Cu++ (imidazole–15N)4, and 65Cu++(imidazole–Dn)4, where n = 1, 2, 3, and 4 for selectively deuterated imidazole. We have observed ENDOR associated with the imidazole protons and the two imidazole nitrogens. The selective deuteration has allowed us to attempt identification of the weakly coupled protons responsible for the ENDOR spectrum, and a comparison of the overall line shape of that spectrum taken at two extreme points of the EPR spectrum suggests that some of the imidazole planes are tilted with respect to the plane of the complex. The ENDOR arising from the nitrogen nearest the copper is primarily isotropic with A(g⊥) = 41.6±1.5 MHz and A(g∥) = 39.8±1.5 MHz. The resonance shows little structure and seems consistent with a picture that requires some inequivalence among the various imidazoles. The remote nitrogen ENDOR reveals both hyperfine and quadrupole effects with approximately isotropic A(14N) = 1.79 MHz, Qz′z′?0.360 MHz, and Qx′x′y′x′?0.349 MHz. These values are in agreement with the results of the nuclear modulation effect [J. Chem. Phys. 69, 4921 (1978)]. The values for the quadrupole constants are thought to be accurate within 10% and are the same as are found in free imidazole. It is also demonstrated that, in this instance, ENDOR and the nuclear modulation effect are complementary in that they have each provided different parts of the same hyperfine spectrum.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70838/2/JCPSA6-75-5-2098-1.pd
Intraoperative ultrasound in brain tumor surgery: A review and implementation guide.
Accurate and reliable intraoperative neuronavigation is crucial for achieving maximal safe resection of brain tumors. Intraoperative MRI (iMRI) has received significant attention as the next step in improving navigation. However, the immense cost and logistical challenge of iMRI precludes implementation in most centers worldwide. In comparison, intraoperative ultrasound (ioUS) is an affordable tool, easily incorporated into existing theatre infrastructure, and operative workflow. Historically, ultrasound has been perceived as difficult to learn and standardize, with poor, artifact-prone image quality. However, ioUS has dramatically evolved over the last decade, with vast improvements in image quality and well-integrated navigation tools. Advanced techniques, such as contrast-enhanced ultrasound (CEUS), have also matured and moved from the research field into actual clinical use. In this review, we provide a comprehensive and pragmatic guide to ioUS. A suggested protocol to facilitate learning ioUS and improve standardization is provided, and an outline of common artifacts and methods to minimize them given. The review also includes an update of advanced techniques and how they can be incorporated into clinical practice
Isotopic constraints on the role of hypohalous acids in sulfate aerosol formation in the remote marine boundary layer
Sulfate is an important component of global atmospheric aerosol, and has
partially compensated for greenhouse gas-induced warming during the
industrial period. The magnitude of direct and indirect radiative forcing of
aerosols since preindustrial times is a large uncertainty in climate models,
which has been attributed largely to uncertainties in the preindustrial
environment. Here, we report observations of the oxygen isotopic composition
(Δ<sup>17</sup>O) of sulfate aerosol collected in the remote marine boundary
layer (MBL) in spring and summer in order to evaluate sulfate production
mechanisms in pristine-like environments. Model-aided analysis of the
observations suggests that 33–50 % of sulfate in the MBL is formed via
oxidation by hypohalous acids (HOX  =  HOBr + HOCl), a production
mechanism typically excluded in large-scale models due to uncertainties in
the reaction rates, which are due mainly to uncertainties in reactive halogen
concentrations. Based on the estimated fraction of sulfate formed via HOX
oxidation, we further estimate that daily-averaged HOX mixing ratios on the
order of 0.01–0.1 parts per trillion (ppt  =  pmol/mol) in the remote MBL
during spring and summer are sufficient to explain the observations
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