10,383 research outputs found
TNT equivalency of M10 propellant
Peak, side-on blast overpressure and scaled, positive impulse have been measured for M10 single-perforated propellant, web size 0.018 inches, using configurations that simulate the handling of bulk material during processing and shipment. Quantities of 11.34, 22.7, 45.4, and 65.8 kg were tested in orthorhombic shipping containers and fiberboard boxes. High explosive equivalency values for each test series were obtained as a function of scaled distance by comparison to known pressure, arrival time and impulse characteristics for hemispherical TNT surface bursts. The equivalencies were found to depend significantly on scaled distance, with higher values of 150-100 percent (pressure) and 350-125 percent (positive impulse) for the extremes within the range from 1.19 to 3.57 m/cube root of kg. Equivalencies as low as 60-140 percent (pressure) and 30-75 percent (positive impulse) were obtained in the range of 7.14 to 15.8 m/cube root of kg. Within experimental error, both peak pressure and positive impulse scaled as a function of charge weight for all quantities tested in the orthorhombic configuration
Intersection tests for single marker QTL analysis can be more powerful than two marker QTL analysis
BACKGROUND: It has been reported in the quantitative trait locus (QTL) literature that when testing for QTL location and effect, the statistical power supporting methodologies based on two markers and their estimated genetic map is higher than for the genetic map independent methodologies known as single marker analyses. Close examination of these reports reveals that the two marker approaches are more powerful than single marker analyses only in certain cases. Simulation studies are a commonly used tool to determine the behavior of test statistics under known conditions. We conducted a simulation study to assess the general behavior of an intersection test and a two marker test under a variety of conditions. The study was designed to reveal whether two marker tests are always more powerful than intersection tests, or whether there are cases when an intersection test may outperform the two marker approach. We present a reanalysis of a data set from a QTL study of ovariole number in Drosophila melanogaster. RESULTS: Our simulation study results show that there are situations where the single marker intersection test equals or outperforms the two marker test. The intersection test and the two marker test identify overlapping regions in the reanalysis of the Drosophila melanogaster data. The region identified is consistent with a regression based interval mapping analysis. CONCLUSION: We find that the intersection test is appropriate for analysis of QTL data. This approach has the advantage of simplicity and for certain situations supplies equivalent or more powerful results than a comparable two marker test
Nesting ecology of migratory golden eagles (Aquila chrysaetos) in Denali National Park, AK
Thesis (M.S.) University of Alaska Fairbanks, 1995Between 1988 and 1993 I measured occupancy of nesting territories and reproduction of golden eagles (Aquila chrysaetos) in Denali National Park, Alaska. I collected data occupancy of nesting territories and three reproductive variables (pairs nesting, pairs producing fledglings, and fledgling production) at 74 nesting territories using three aerial surveys each year. During my study, annual fledgling production varied nearly threefold, from 20 fledglings in 1992 to 58 fledglings in 1989. Although rates of nesting territory occupancy did not vary significantly among years (yj = 8.21, d.f. = 5, P = 0.114), I noted significant variation in the proportion of pairs laying eggs (X2 = 33.12, d.f. = 5, P < 0.001) and the proportion of pairs fledging young (X2 = 16.03, d.f. = 5, P = 0.007) among years. Decreases in pairs laying eggs were correlated with decreases in average daily numbers of snowshoe hare (Lepus americanus) and willow ptarmigan (Lagopus lagopus) observed in the study area (rs = 0.83, P = 0.04)
Osteopathic clinical reasoning: an ethnographic study of perceptual diagnostic judgments, metacognition, and reflective practice
A thesis submitted to the University of Bedfordshire in partial fulfilment of the requirements for the degree of Professional DoctorateThis thesis explores the use of reflective practice in osteopathic medicine and uses the
method to narrate my work as an osteopathic practitioner. It explores the development of
perceptual diagnostic judgments, and the role of metacognition, intuition and palpation in
osteopathic clinical reasoning.
A qualitative interpretive approach was used with a novel narrative method as an
organising structure. This was broadly based around reflective practice models of Gibbs,
(1988), Kolb, (1984) and Carper (1978) and the ideas of Schön (1983). Descriptive texts
were constructed from notes taken of my thoughts whilst in the presence of patients. This
allowed access, as closely as possible, to my decision making process. Finally, the
descriptive texts were expanded into narratives through dialogue with the existing
literature and peer review. The narratives were then analysed using thematic analysis to
derive an understanding of concepts arising from the data.
This thesis argues that osteopathic clinical reasoning involves multisensory perceptual
diagnostic judgments that begin as soon as the patient enters the clinic, and arise as a
result of the use of mental and visual imagery and embodied senses. The multisensory
information that is detected by a practitioner activates pattern recognition, analytic
reasoning and provides explicit feedback used in decision making. Diagnosis occurs as a result of piecing together and interpreting the multisensory information whilst maintaining
awareness of other diagnostic possibilities.
The findings also suggest that osteopathic clinical reasoning involves the supervision of
cognition by the metacognitive processes of meta-knowledge (MK), meta-experiences
(ME), and meta-skills (MS). The latter are used to plan, monitor, analyse, predict,
evaluate and revise the consultation and patient management as suggested by Pesut and
Herman (1992). ME is demonstrated by the presence of judgments of learning used to
ensure sufficient information has been gathered, and feelings of rightness that are used
to perceive the correctness of information arriving and decisions made.
The use of reflective practice in this research has developed the understanding of
osteopathic clinical reasoning, and demonstrated that it provides a powerful conduit for
change in practice. As a result, it enables the provision of better patient-centred
osteopathic healthcare incorporating the biopsychosocial model of healthcare. Although rooted in my own osteopathic practice style and strategies, it should have resonance for
those within the discipline of osteopathy and has implications for osteopathic education,
training and research
Self-pulsing dynamics in a cavity soliton laser
The dynamics of a broad-area vertical-cavity surface-emitting laser (VCSEL) with frequency-selective feedback supporting bistable spatial solitons is analyzed experimentally and theoretically. The transient dynamics of a switch-on of a soliton induced by an external optical pulse shows strong self-pulsing at the external-cavity round-trip time with at least ten modes excited. The numerical analysis indicates an even broader bandwidth and a transient sweep of the center frequency. It is argued that mode-locking of spatial solitons is an interesting and viable way to achieve three-dimensional, spatio-temporal self-localization and that the transients observed are preliminary indications of a transient cavity light bullet in the dynamics, though on a non negligible background
The Interaction between the ISM and Star Formation in the Dwarf Starburst Galaxy NGC 4214
We present the first interferometric study of the molecular gas in the
metal-poor dwarf starburst galaxy NGC 4214. Our map of the 12CO(1-0) emission,
obtained at the OVRO millimeter array, reveals an unexpected structural wealth.
We detected three regions of molecular emission in the north-west (NW),
south-east (SE) and centre of NGC 4214 which are in very different and distinct
evolutionary stages (total molecular mass: 5.1 x 10^6 M_sun). These differences
are apparent most dramatically when the CO morphologies are compared to optical
ground based and HST imaging: massive star formation has not started yet in the
NW region; the well-known starburst in the centre is the most evolved and star
formation in the SE complex started more recently. We derive a star formation
efficiency of 8% for the SE complex. Using high--resolution VLA observations of
neutral hydrogen HI and our CO data we generated a total gas column density map
for NGC 4214 (HI + H_2). No clear correlation is seen between the peaks of HI,
CO and the sites of ongoing star formation. This emphasizes the irregular
nature of dwarf galaxies. The HI and CO velocities agree well, so do the
H-alpha velocities. In total, we cataloged 14 molecular clumps in NGC 4214. Our
results from a virial mass analysis are compatible with a Galactic CO-to-H_2
conversion factor for NGC 4214 (lower than what is usually found in metal-poor
dwarf galaxies).Comment: accepted for publication in the AJ (February 2001), full ps file at:
ftp://ftp.astro.caltech.edu/users/fw/ngc4214/walter_prep.p
Blood lactate clearance during active recovery after an intense running bout depends on the intensity of the active recovery
High-intensity exercise training contributes to the production and accumulation of blood lactate, which is cleared by active recovery. However, there is no commonly agreed intensity or mode for clearing accumulated blood lactate. We studied clearance of accumulated blood lactate during recovery at various exercise intensities at or below the lactate threshold after high-intensity interval runs that prompted lactate accumulation. Ten males repeated 5-min running bouts at 90% of maximal oxygen uptake ([Vdot]O2max), which increased blood lactate concentration from 1.0 ± 0.1 to 3.9 ± 0.3 mmol · l-1. This was followed by recovery exercises ranging from 0 to 100% of lactate threshold. Repeated blood lactate measurements showed faster clearance of lactate during active versus passive recovery, and that the decrease in lactate was more rapid during higher (60-100% of lactate threshold) than lower (0-40% of lactate threshold) (P < 0.05) intensities. The more detailed curve and rate analyses showed that active recovery at 80-100% of lactate threshold had shorter time constants for 67% lactate clearance and higher peak clearance rates than 40% of lactate threshold or passive recovery (P < 0.05). Finally, examination of self-regulated intensities showed enhanced lactate clearance during higher versus lower intensities, further validating the intensity dependence of clearance of accumulated blood lactate. Therefore, active recovery after strenuous exercise clears accumulated blood lactate faster than passive recovery in an intensity-dependent manner. Maximum clearance occurred at active recovery close to the lactate threshold
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