111 research outputs found
Adverse Childhood Experiences in the New Mexico Juvenile Justice Population
Faculty from the University of New Mexico (UNM) School of Law and the UNM School of Medicine, and New Mexico’s Children, Youth and Families Department (CYFD) initiated a joint project to look at the prevalence of Adverse Childhood Experiences (ACEs) nationally and in New Mexico. The study was intended to better establish the association between early childhood trauma and delinquency, as well as to explore the role that law and medicine can play in ensuring better health and juvenile justice outcomes for children who have experienced ACEs
Laboratory study on the drag force distribution within model forest canopies in turbulent shear flow, A
CER67-68GH-JHN50.March 1968.Includes bibliographical references (page 20).Prepared under U.S. Army Research Grant DA-AMC-28-043-65-G20 U.S. Army Material Command Washington 25, D.C.The objective of this study was to determine the distribution of the tree drag force within various model forest canopies subjected to various ambient wind conditions. Ultimately this information may be related to diffusion within the forest canopy. The influence on individual tree drag due to neighboring trees was investigated by arranging the trees in various configurations of columns and rows, the columns being parallel to the ambient wind and the rows being perpendicular. Two tree spacings for the columns and rows were investigated. Furthermore, a large forest canopy field was investigated that covered an area of twenty-one square meters. For this arrangement it was determined that the tree drag field can be classified into two zones - an initial zone and a steady decay zone. In order to study the influence of the boundary layer development on tree drag, the various arrangements of trees were tested under a thin boundary layer condition and under a thick boundary layer condition. In the course of this study a strain gage force dynamometer was developed that can reliably measure a drag force as small as 0.1 gram on a model tree.Under grant DA-AMC-28-043-65-G20
Study of wind loading on tall structures: Atlantic-Richfield Plaza buildings, A
CER68-69WZS-JEC-GH-36.August 1969.Includes bibliographical references.For Metronics Associates, Inc.Wind loading on a 1:384 scale model of Atlantic-Richfield Plaza Buildings 666 ft. high was investigated in a thick turbulent boundary-layer wind tunnel. Measurements of mean velocity, turbulence intensity and boundary-layer thickness upstream of the model structure verified that the wind-tunnel flow was an adequate simulation of the atmospheric-surface-layer conditions over the full-scale urban area. Mean pressure and pressure fluctuations were measured for three different wind directions (NE, N and NW). Generally, the mean pressure was found to be the largest near the top and smallest close to the base. An opposite variation was observed for the fluctuating and instantaneous peak pressures. The largest pressure fluctuations were obtained in the case of the N wind. The turbulence energy spectra of the upstream flow and surface pressure-fluctuations spectra exhibited consistently a similar qualitative behavior. This is suggestive that the upstream turbulence has a predominant role, together with the wake, in producing the pressure fluctuations. Direct measurement of mean and fluctuating overturning moment by means of a strain-gage dynamometer revealed that the latter ranged up to about ± 34% of the former. Root-mean square values of the fluctuating moment were also determined in an effort to relate it to the pressure fluctuations and upstream turbulence
Regulation of vascular smooth muscle cell function by mechanical strain
Thesis (Ph. D.)--Massachusetts Institute of Technology, Whitaker College of Health Sciences and Technology, 1996.Includes bibliographical references (p. 173-192).by George Chen-hsi Cheng.Ph.D
Perfect simulation from unbiased simulation
We show that any application of the technique of unbiased simulation becomes
perfect simulation when coalescence of the two coupled Markov chains can be
practically assured in advance. This happens when a fixed number of iterations
is high enough that the probability of needing any more to achieve coalescence
is negligible; we suggest a value of . This finding enormously
increases the range of problems for which perfect simulation, which exactly
follows the target distribution, can be implemented. We design a new algorithm
to make practical use of the high number of iterations by producing extra
perfect sample points with little extra computational effort, at a cost of a
small, controllable amount of serial correlation within sample sets of about 20
points. Different sample sets remain completely independent. The algorithm
includes maximal coupling for continuous processes, to bring together chains
that are already close. We illustrate the methodology on a simple, two-state
Markov chain and on standard normal distributions up to 20 dimensions. Our
technical formulation involves a nonzero probability, which can be made
arbitrarily small, that a single perfect sample point may have its place taken
by a "string" of many points which are assigned weights, each equal to ,
that sum to~. A point with a weight of is a "hole", which is an object
that can be cancelled by an equivalent point that has the same value but
opposite weight .Comment: 17 pages, 4 figures; for associated R scripts, see
https://github.com/George-Leigh/PerfectSimulatio
Estimating the natural mortality rate of saucer scallops (Ylistrum balloti) on the Queensland east coast from tag-recaptures
Saucer scallops (Ylistrum balloti) were tagged and released on four occasions inside two areas closed to fishing (Hervey Bay A, HBA; and Yeppoon B, YB) on the Queensland (Australia) east coast and their subsequent recaptures over the following months were used to measure the instantaneous rate of natural mortality (M). A total of 13,295 scallops were tagged and 526 recaptured over the 15 month-long experiment (May 2018 to August 2019). Three statistical approaches were applied to the experimental design and analysis of the tagging data, based on 1) the Brownie model, 2) a modified version of the Brownie model, and 3) a binomial logistic regression model of recaptures. Estimates of M based on the Brownie model were much higher for tagged scallops that were at liberty over summer months compared to those at liberty over the winter months, possibly indicating seasonal variation. The logistic model parameter estimates indicated the proportion of recaptures differed significantly with the lunar phase at recapture, scallop size class, the number of days the scallops were at liberty and the interaction between days-at-liberty and closure. All three approaches indicated M was higher in HBA compared to YB. Mean estimates of M for the whole fishery, derived by averaging estimates from both closures, ranged from a minimum of 1.461 year–1 for the logistic model, to 1.501 year–1 for the Brownie model, to 1.548 year–1 (variable recapture rate) and 1.594 year–1 (fixed recapture rate) for the modified Brownie model. Estimates from all three approaches were higher than the previous estimate that was published over 40 years ago and possible reasons for the increase are discussed
Stock assessments of bream, whiting and flathead (Acanthopagrus australis, Sillago ciliata and Platycephalus fuscus) in South East Queensland
Yellowfin bream, sand whiting and dusky flathead are major target species for both commercial and recreational fishers in south east Queensland. Their fishery and regional social and economic importance prompted stock assessments to inform on the sustainability of fishing. The assessments covered both estuarine and ocean-beach waters between Baffle Creek north of Bundaberg and Coolangatta on the Gold Coast.
Over the last five years (2013 to 2017), the South East Queensland total harvest for yellowfin bream, sand whiting and dusky flathead averaged 242, 272 and 121 tonnes per year respectively.
The catches split for bream was 54 per cent commercial versus 46 per cent recreational, 77 per cent commercial versus 23 per cent recreational for whiting and 36 per cent commercial versus 64 per cent recreational for flathead.
The stock assessments used commercial, recreational, charter and indigenous catch, and research data. Inputs to the model included fish harvest sizes (1945 to present), standardised catch rates from commercial net logbook data (1988 to present), and fish age–length data collected from the fishery (2007 to present).
All three assessments were challenging due to lack of contrast in the data since the commercial logbook system began in 1988. All three species had been subject to high harvests prior to that year, and commercial catch rates had not varied much since then. In addition, the only available catch rates came from net fishing, which can target whole schools of fish. Net catch rates may be ‘hyperstable’ and not sensitive to trends in fish population size.
Bream biomass was estimated to be at 33.8 per cent of unfished biomass. The equilibrium maximum sustainable yield (MSY) was estimated as 420 tonnes per year (commercial and recreational sectors combined, and Moreton and Fraser regions combined). The model indicated that maintenance of a harvest size of 220 t ⁄ yr will recover the biomass to 60 per cent of unfished in about 25 years. A lower harvest of 150 t ⁄ yr would recover to 60 per cent in about 12 years.
Whiting biomass in 2017 was estimated as 28.7 per cent of unfished biomass, which is approximately the biomass corresponding to MSY (denoted BMSY). The model’s estimate of equilibrium MSY was 452 t ⁄ yr. Current combined harvest size is approximately equal to the equilibrium harvest at 60 per cent unfished biomass (B60). Rebuilding of the stock from its current level to B60, however, would require the harvest to be reduced, ideally to about 150 t (commercial and recreational sectors combined, and Moreton and Fraser regions combined) to rebuild within about five years. Yearly harvests between 150 and 270 t ⁄ yr would recover the stock more slowly; the midpoint 210 t ⁄ yr would reach B60 in about seven years.
The status of flathead is more uncertain than bream and whiting. The precautionary estimate of dusky flathead biomass in the Moreton region in 2017 was between 36 per cent and 39 per cent of unfished spawning biomass, approximately equal to or slightly below BMSY. The estimated MSY was 104 t ⁄ yr to 112 t ⁄ yr, approximately equal to current harvests. Recovery of the spawning stock to 60 per cent in the Moreton region would require the harvest to be reduced, ideally to 63 t ⁄ yr (commercial and recreational sectors combined, Moreton region only) which would recover to B60 within eight years. An intermediate harvest level of 73 t ⁄ yr would reach B60 within 16 years. In the Fraser region, fishing pressure on flathead was lower, and 2017 estimated spawning biomass was 70 per cent of unfished.
Although the results for flathead are already precautionary, additional caution may be needed in view of fishing club catch rates which date back to the 1950s and indicate that flathead were already heavily fished by 1988
- …