2,354 research outputs found
Development of sound analysis equipment for sonar research, part II
Late in 1955 the Deep Water Propagation Committee recommended procurement of 10 sets of sound analysis equipment to be distributed to laboratories working in the field of underwater acoustics. This recommendation was made to be one of the objectives of Contract Nonr-2129. The equipment, including filters for spectrum analysis, was to compute the time integral of the square of the filter output voltages as discussed by Officer and Dietz (1953), WHOI Ref. No. 53-46. In view of the fact that correlation studies are becoming more important it was recommended that the equipment have an optional mode of operation in which it could compute the time integral of the product of two voltages. Multichannel computers were recommended because analysis of data from one hydrophone for one frequency band at one time is much too slow in view of the large amount of data to be processed. Eight channels per computer were chosen because this is the largest number available in standard direct-writing recorders.Undersea Warfare Branch, Office of Naval Research, under Contract Nonr- 2129(00) (NR 261-104)
Remote acoustic sensing of the particulate phase of industrial chemical wastes and sewage sludge : report on the seasonal variability of the dispersion of the particulate phase as observed from three cruises, July 1977, January-February 1978, and April 1978
The seasonal variability of the dispersion of the particulate
phase of industrial chemical waste has been studied with acoustic
backscattering techniques at Deep Water Dumpsite 106 (DWD 106).
The vertical dispersion of the particulates has been found to be
strongly dependent on the depth of the mixed layer and the magnitude
of the density gradient associated with the seasonal thermocline.
The horizontal dispersion of the particulates as a function of
depth has been found to be strongly dependent on the shear present
in the water column. Entire waste plumes have been found to be
advected out of the dumpsite in less than 24 hours when the area
is occupied by a warm core ring.
Simple calculations based upon Stoke's law are presented to
reveal the impact of variable oceanic density structure on the
sink rate of particles and to indicate the need for incorporating
these considerations into numerical models.
A short discussion is presented on (1) the need to make field
measurements on the magnitude of both turbulence and shear in the
water column and (2) the need to incorporate shear and turbulence-dependent
calculations for the sink rates of particles into those
numerical models which may be used to predict the particulate
and effluent dispersion rates at DWD 106.Prepared for the National Oceanic and Atmospheric Administration
under Grants 04-7-158-44054, NA79AA-D-00030 and Ocean
Dumping Grant 04-8-MOl-43
Mortality of fish subjected to explosive shock as applied to oil well severance on Georges Bank
A very extensive bibliography of papers on underwater explosions
and their effects on marine life has been collected and
summarized. When exposed to blast effects, vertebrates with swim
bladders or lungs that contain gas are at least an order of
magnitude more sensitive than other life. Regression analysis of
several different experiments on explosive damage to fish has been
combined with reports of fish concentrations and explosives used
in oil well severance in order to estimate the probable extent of
damage to fish populations from a limited number of severance
explosions. Damage per explosion should not be significant and is
probably considerably less than that caused by a one hour tow of a
bottom trawl net.Prepared for the Technology Assessment and
Research Program of the Minerals Management
Service, Department of the Interior, under
Contract 14-08-0001-18920
Sound channel propagation through eddies southeast of the Gulf Stream
Also published as: Journal of the Acoustical Society of America 68 (1980): 1750-1767Acoustical signals at 270 Hz from SOFAR floats drifting in the region southeast of the Gulf Stream were recorded during most of 1975 from a near axis sound channel hydrophone near Bermuda. The amplitude levels received exhibit a large increase (12â18 dB) commencing about 24 July, following a long period (March to July) of relatively lower peak level amplitudes. A major part of the increase can be attributed to the influence of a large cyclonic eddy (Gulf Stream ring) that passed slowly between the SOFAR floats and Bermuda. Such an eddy produces a large sound speed anomaly that extends to depths below the axis of the sound channel. On 24 July, two SOFAR floats were known to have approximately the same sound transmission path through the edge of the large eddy. The sound transmission peaks occur when no ocean eddy is between the SOFAR floats and the receiver. Their spacing shows they occur at regular refraction caustics in the sound channel. When the sound transmission path passes through an eddy, these transmission focal distances are shifted to greater range and the signal level may be greatly enhanced. The decrease of caustic peak intensities with range is 5 dB per double distance, and this agrees with theory. Several different levels of peak acoustic intensity occur and these result from two float depths and oceanic thermocline oscillations.Prepared for the Office of Naval Research under Contract
N00014-74-C-0262; NR 083-004¡
Communication Structures of Supplemental Voluntary Kin Relationships
Although scholars have constructed typologies of voluntary (fictive) kin, few have considered challenges and opportunities of interaction and relationships between biolegal and voluntary kin. This study focused on one type of voluntary kin, supplemental voluntary kin, relationships that often arise because of differing values, underperformed roles, or physical distance from the biolegal family, and wherein relationships are maintained with biolegal and voluntary kin. We examined how these family systems are constructed via interactions in relational triads of âlinchpinâ persons between biolegal family and voluntary kin. From in-depth interviews with 36 supplemental voluntary kin, we examined themes in the linchpinsâ discourse surrounding the interaction, rituals, and ideal relationship between biolegal family and voluntary kin. We constructed a typology of four relational triads representing these relationships: intertwined, limited, separate, and hostile. We describe the structure and communication within each type, and implications for helping families with these triangulated voluntary kin relationships
Territorial Developments Based on Graffiti: a Statistical Mechanics Approach
We study the well-known sociological phenomenon of gang aggregation and
territory formation through an interacting agent system defined on a lattice.
We introduce a two-gang Hamiltonian model where agents have red or blue
affiliation but are otherwise indistinguishable. In this model, all
interactions are indirect and occur only via graffiti markings, on-site as well
as on nearest neighbor locations. We also allow for gang proliferation and
graffiti suppression. Within the context of this model, we show that gang
clustering and territory formation may arise under specific parameter choices
and that a phase transition may occur between well-mixed, possibly dilute
configurations and well separated, clustered ones. Using methods from
statistical mechanics, we study the phase transition between these two
qualitatively different scenarios. In the mean-field rendition of this model,
we identify parameter regimes where the transition is first or second order. In
all cases, we have found that the transitions are a consequence solely of the
gang to graffiti couplings, implying that direct gang to gang interactions are
not strictly necessary for gang territory formation; in particular, graffiti
may be the sole driving force behind gang clustering. We further discuss
possible sociological -- as well as ecological -- ramifications of our results
"It's making contacts" : notions of social capital and implications for widening access to medical education
Acknowledgements Our thanks to the Medical Schools Council (MSC) of the UK for funding Study A; REACH Scotland for funding Study B; and Queen Mary University of London, and to the medical school applicants and students who gave their time to be interviewed. Our thanks also to Dr Sean Zhou and Dr Sally Curtis, and Manjul Medhi, for their help with data collection for studies A and B respectively. Our thanks also to Dr Lara Varpio, Uniformed Services University of the USA, for her advice and guidance on collating data sets and her comments on the draft manuscript.Peer reviewedPublisher PD
A Randomised Trial Comparing Genotypic and Virtual Phenotypic Interpretation of HIV Drug Resistance: The CREST Study
OBJECTIVES: The aim of this study was to compare the efficacy of different HIV drug resistance test reports (genotype and virtual phenotype) in patients who were changing their antiretroviral therapy (ART). DESIGN: Randomised, open-label trial with 48-week followup. SETTING: The study was conducted in a network of primary healthcare sites in Australia and New Zealand. PARTICIPANTS: Patients failing current ART with plasma HIV RNA > 2000 copies/mL who wished to change their current ART were eligible. Subjects were required to be > 18 years of age, previously treated with ART, have no intercurrent illnesses requiring active therapy, and to have provided written informed consent. INTERVENTIONS: Eligible subjects were randomly assigned to receive a genotype (group A) or genotype plus virtual phenotype (group B) prior to selection of their new antiretroviral regimen. OUTCOME MEASURES: Patient groups were compared for patterns of ART selection and surrogate outcomes (plasma viral load and CD4 counts) on an intention-to-treat basis over a 48-week period. RESULTS: Three hundred and twenty seven patients completing > one month of followup were included in these analyses. Resistance tests were the primary means by which ART regimens were selected (group A: 64%, group B: 62%; p = 0.32). At 48 weeks, there were no significant differences between the groups for mean change from baseline plasma HIV RNA (group A: 0.68 log copies/mL, group B: 0.58 log copies/mL; p = 0.23) and mean change from baseline CD4+ cell count (group A: 37 cells/mm(3), group B: 50 cells/mm(3); p = 0.28). CONCLUSIONS: In the absence of clear demonstrated benefits arising from the use of the virtual phenotype interpretation, this study suggests resistance testing using genotyping linked to a reliable interpretive algorithm is adequate for the management of HIV infection
Expert Premier League soccer managersâ use of transformational leadership behaviours and attitude towards sport integrity: An intrinsic case study
The present study is the first to examine transformational leadership behaviours and integrity attitudes of expert, Premier League and International level football managers. To provide a rich, detailed exploration of the expert managersâ experiences, a qualitative approach was adopted utilising holistic content analysis. Constructed narratives revealed that the key behaviours demonstrated were inspirational messages or team talks (i.e. inspirational motivation), empathy (i.e. individualised consideration), introducing new training methods (i.e. intellectual stimulation), using exemplar players (i.e. appropriate role modelling), and goal setting (i.e. high performance expectations). However, the use and effect of such behaviours varied greatly between managers. Each of the managers also claimed to have been willing to âbend the rulesâ as a player and frequently used euphemistic labels to describe such behaviour. However, upon entering management, all three managers claimed to have adjusted such attitudes without providing an explanation for this
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