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PubMed1995

Forecasting requirements for physical therapists.

In response to the existing undersupply of physical therapists and the projected changes of the health care reform era, it is prudent for the profession to consider implementing a training strategy that would bring the supply of physical therapists in line with requirements. Before such a training strategy could be developed, however, the physical therapy community would need to produce a requirements forecast. This article compares the uses and limitations of the two major methods for generating health professions requirements--the "need-based" and "demand-based" approaches--and recommends a pragmatic, tailored approach to determining physical therapist requirements that uses easily obtainable data on staffing patterns of managed care plans. The proposed method draws from both need-based and demand-based models to produce complementary data on which to base policy formation.

Forecasting↗

PubMed1999

Radiation hybrid map of the mouse genome.

Radiation hybrid (RH) maps are a useful tool for genome analysis, providing a direct method for localizing genes and anchoring physical maps and genomic sequence along chromosomes. The construction of a comprehensive RH map for the human genome has resulted in gene maps reflecting the location of more than 30,000 human genes. Here we report the first comprehensive RH map of the mouse genome. The map contains 2,486 loci screened against an RH panel of 93 cell lines. Most loci (93%) are simple sequence length polymorphisms (SSLPs) taken from the mouse genetic map, thereby providing direct integration between these two key maps. We performed RH mapping by a new and efficient approach in which we replaced traditional gel- or hybridization-based assays by a homogeneous 5'-nuclease assays involving a single common probe for all genetic markers. The map provides essentially complete connectivity and coverage across the genome, and good resolution for ordering loci, with 1 centiRay (cR) corresponding to an average of approximately 100 kb. The RH map, together with an accompanying World-Wide Web server, makes it possible for any investigator to rapidly localize sequences in the mouse genome. Together with the previously constructed genetic map and a YAC-based physical map reported in a companion paper, the fundamental maps required for mouse genomics are now available.

Animals↗

PubMed2000

Physical model-based non-rigid registration incorporating statistical shape information.

This paper describes two new atlas-based methods of 2D single modality non-rigid registration using the combined power of physical and statistical shape models. The transformations are constrained to be consistent with the physical properties of deformable elastic solids in the first method and those of viscous fluids in the second, to maintain smoothness and continuity. A Bayesian formulation, based on each physical model, an intensity similarity measure, and statistical shape information embedded in corresponding boundary points, is employed to derive more accurate and robust approaches to non-rigid registration. A dense set of forces arises from the intensity similarity measure to accommodate complex anatomical details. A sparse set of forces constrains consistency with statistical shape models derived from a training set. A number of experiments were performed on both synthetic and real medical images of the brain and heart to evaluate the approaches. It is shown that statistical boundary shape information significantly augments and improves physical model-based non-rigid registration and the two methods we present each have advantages under different conditions.

Brain↗

PubMed2005

A decoy set for the thermostable subdomain from chicken villin headpiece, comparison of different free energy estimators.

BACKGROUND: Estimators of free energies are routinely used to judge the quality of protein structural models. As these estimators still present inaccuracies, they are frequently evaluated by discriminating native or native-like conformations from large ensembles of so-called decoy structures. RESULTS: A decoy set is obtained from snapshots taken from 5 long (100 ns) molecular dynamics (MD) simulations of the thermostable subdomain from chicken villin headpiece. An evaluation of the energy of the decoys is given using: i) a residue based contact potential supplemented by a term for the quality of dihedral angles; ii) a recently introduced combination of four statistical scoring functions for model quality estimation (FRST); iii) molecular mechanics with solvation energy estimated either according to the generalized Born surface area (GBSA) or iv) the Poisson-Boltzmann surface area (PBSA) method. CONCLUSION: The decoy set presented here has the following features which make it attractive for testing energy scoring functions:1) it covers a broad range of RMSD values (from less than 2.0 A to more than 12 A);2) it has been obtained from molecular dynamics trajectories, starting from different non-native-like conformations which have diverse behaviour, with secondary structure elements correctly or incorrectly formed, and in one case folding to a native-like structure. This allows not only for scoring of static structures, but also for studying, using free energy estimators, the kinetics of folding;3) all structures have been obtained from accurate MD simulations in explicit solvent and after molecular mechanics (MM) energy minimization using an implicit solvent method. The quality of the covalent structure therefore does not suffer from steric or covalent problems. The statistical and physical effective energy functions tested on the set behave differently when native simulation snapshots are included or not in the set and when averaging over the trajectory is performed.

Animals↗

PubMed1998

Health status after recovery from burn injury.

Outcome studies after burn injury have become increasingly important as overall mortality from injury has decreased. The present study, concerning physical and psychosocial aspects, is the second part of our larger survey of outcome after burn. The basis of our study instrument was the Abbreviated Burn Specific Health Scale. A postal survey was conducted among 315 patients aged 15-65 years, treated at Töölö Hospital Burns Unit between 11 November 1988 and 31 December 1994. The study series analysed consisted of 124 patients, whose mean total body surface area (TBSA) burned was 13.0%, mean full-thickness (FT) burns 6.2%, mean age 37 years and mean time of hospital treatment 16 days. Statistical analyses were performed with non-parametric tests and a probability level of 0.05 as the limit of statistical significance. Physical function was affected by the severity of the burn and by hand burns. Body image was influenced by FT burns but not by hand or facial injuries. Sexual life was affected by FT burns larger than 20%. Patients older than 25 years, those with TBSA greater than 30%, FT greater than 20% or time of hospitalization over one month were concerned about their general health. The effect of burns on patients' physical and psychosocial life was, however, slight, even with respect to severe injuries.

Abbreviated Injury Scale↗

PubMed2005

Bose-Einstein condensates and precision measurements.

An ongoing challenge in physics is to make increasingly accurate measurements of physical quantities. Bose-Einstein condensates in atomic gases are ideal candidates for use in precision measurement schemes since they are extremely cold and have laser-like coherence properties. In this paper, we review these two attributes and discuss how they could be exploited to improve the resolution in a range of different measurements.

Computer Simulation↗

PubMed2003

Application of negative binomial modeling for discrete outcomes: a case study in aging research.

We present a case study using the negative binomial regression model for discrete outcome data arising from a clinical trial designed to evaluate the effectiveness of a prehabilitation program in preventing functional decline among physically frail, community-living older persons. The primary outcome was a measure of disability at 7 months that had a range from 0 to 16 with a mean of 2.8 (variance of 16.4) and a median of 1. The data were right skewed with clumping at zero (i.e., 40% of subjects had no disability at 7 months). Because the variance was nearly 6 times greater than the mean, the negative binomial model provided an improved fit to the data and accounted better for overdispersion than the Poisson regression model, which assumes that the mean and variance are the same. Although correcting the variance and corresponding test statistics for overdispersion is a standard procedure in the Poisson model, the estimates of the regression parameters are inefficient because they have more sampling variability than is necessary. The negative binomial model provides an alternative approach for the analysis of discrete data where overdispersion is a problem, provided that the model is correctly specified and adequately fits the data.

Activities of Daily Living↗

PubMed2004

Advancing beyond the average: the importance of mentoring in professional achievement.

The profession of respiratory care is founded on rigorous scientific research, which in turn depends on rigorous training in research methods. Only a small part of that training is from written and audiovisual materials; the most important aspects of becoming a respiratory researcher are learned from. Becoming a thoroughly-involved respiratory care professional, then a researcher, and then a mentor is challenging but rich with the rewards of contributing to the advancement of science and, thereby, to the care and comfort of our patients. Becoming a respiratory researcher begins with. Only those with a burning desire to excel, to discover truth, and to contribute to the advancement of the profession will persevere through the setbacks and bring a research project to final fruition. The second requirement for long-term success is learning to maintain between enthusiasm and realism. It is crucial to avoid taking on more than you can realistically do, and it is necessary to devote adequate time to your family and/or non-work-related pursuits and recreation. The third aspect of becoming a contributor to respiratory care research is rigorous and ongoing education in the of respiratory care, the methods of medical research, and the basic sciences and mathematics that underlie the profession, including some calculus, engineering physics, and statistics. You must understand research design, critical analysis of research, and numerous aspects of presentation, including clear writing and concise speaking. The fourth aspect is : you must have a strong commitment to obtaining accurate, reproducible, and meaningful data. You must sustain strong attention to detail; mentors are essential because they teach the needed discipline, the required measurement skills, and how to select the appropriate equipment with which to conduct the research. is the fifth aspect. In addition to planning and using your time wisely, you must learn what are realistic expectations about how long a project will take, when to ask for help, and when to stop because you have reached your physical or mental limit and you need to rest and devote some time to your nutrition and recreation. The sixth aspect is : having achieved the basic skills and gained a fair amount of experience, your efficiency improves and you begin to achieve more in a day; you begin to start mentoring others; you can confidently and quickly handle multiple projects; if you don't know the answers you know where to find them; you are seen as an authority and people ask you for consultations and presentations and to participate in committees. The final aspect is, meaning that your practice of respiratory care reaches a level at which you meet challenges for which you feel you have no response in memory and yet you succeed.

Humans↗

PubMed2005

Modified constraint-induced movement therapy for young children with hemiplegic cerebral palsy: a pilot study.

The objective of the study was to evaluate the effectiveness of modified constraint-induced movement therapy in young children with hemiplegia. It was a single-case experimental design using children as their own controls. Assessment was at entry to the study and subsequently at 4-weekly intervals. A 4-week baseline period with no hand treatment, controlling for maturation, was followed by a 4-week treatment period and a second 4-week period with no hand treatment to measure carry-over. Treatment consisted of twice-weekly 1-hour sessions of structured activities with a therapist and a home programme for non-treatment days. Only verbal instruction and gentle restraint of the unaffected arm were used to encourage use of the affected arm. Nine children (six males, three females; median age 31 mo, age range 21 to 61 mo) presenting with congenital spastic hemiplegia (five right side, four left side) were involved in the study. Changes in hand function were evaluated with the Quality of Upper Extremity Skills Test. Improvement was seen throughout the study with statistical significance, using the Wilcoxon signed rank test, of 0.01 immediately after treatment. Results of this pilot study suggest that this modification of constraint-induced movement therapy may be an effective way of treating young children with hemiplegia. Future work is planned to consolidate and develop these results.

Cerebral Palsy↗

PubMed1999

From individuals to aggregations: the interplay between behavior and physics.

This paper analyses the processes by which organisms form groups and how social forces interact with environmental variability and transport. For aquatic organisms, the latter is especially important-will sheared or turbulent flows disrupt organism groups? To analyse such problems, we use individual-based models to study the environmental and social forces leading to grouping. The models are then embedded in turbulent flow fields to gain an understanding of the interplay between the forces acting on the individuals and the transport induced by the fluid motion. Instead of disruption of groups, we find that flows often enhance grouping by increasing the encounter rate among groups and thereby promoting merger into larger groups; the effect breaks down for strong flows. We discuss the transformation of individual-based models into continuum models for the density of organisms. A number of subtle difficulties arise in this process; however, we find that a direct comparison between the individual model and the continuum model is quite favorable. Finally, we examine the dynamics of group statistics and give an example of building an equation for the spatial and temporal variations of the group-size distribution from the individual-based simulations. These studies lay the groundwork for incorporating the effects of grouping into models of the large scale distributions of organisms as well as for examining the evolutionary consequences of group formation.

Animals↗

PubMed2004

Fechner as a statistician.

The work of Gustav Theodor Fechner (1801-1887) related to probability and statistics and, in particular, to the treatment of observations is described. From a mathematical point of view his arguments were often insufficient, but his work proved to be highly fruitful, and the relevant comments of such scholars as Pearson and von Mises are presented. As the originator of psychophysics, Fechner opened up a new field for quantification. Subsequent workers rejected some of his findings, while at the same time acknowledging their debt to him.

Differential Threshold↗

PubMed1991

Estimating the sensitivity of breast cancer screening--experience with the Honolulu BCDDP data.

The 'capture-recapture' models for estimating breast cancer screening sensitivity can be generalized to include factors that affect sensitivity such as cancer size. Including such factors can help reduce the covariance between mammographic and physical exam sensitivity, which will improve the estimates. One model relating sensitivity to cancer length is presented and tested using data from the Honolulu Breast Cancer Detection Demonstration Project (BCDDP). The model predicts sensitivity fairly well for large breast cancers, but underestimates sensitivity for small cancers. Using both mammography and physical examination, the total screening sensitivity is estimated as 0.91 +/- 0.03 for cancers longer than 12 mm (for the second through fifth screenings for Honolulu and Tucson screening data combined). Limited data suggest similar screening sensitivities for Orientals and Caucasians in Hawaii. Shortcomings of the BCDDP data include inaccurate measurements of cancer length. Suggestions to improve data for future work are given.

Breast Neoplasms↗

PubMedDate not supplied

[Selection of the SHF discharge type for the processing of carbon dioxide and hydrogen in a physical-chemical life support system].

Compared are contrasted are moving, stationary, and combined SHF-discharges, methods of discharge generation and diagnostics of the discharge temperature, electron concentration in the discharge tube. and SHF contribution. A combination of the SHF and arc discharges was selected for prototyping the carbon dioxide and hydrogen processor within a physical-chemical life support system. To sustain temperature in the interval between 1000 and 3500 degrees C to support the initial Bosch reaction, a low-power (30-50 mA) glow discharge will be used instead of the continuous current arc (3-5 A). This combination increases plasma efficiency and is suitable for designing a non-inertia air supply within the space life support system.

Atmosphere↗

PubMed2003

The physics of surfactant dissolution.

We have examined the early stages of surfactant dissolution and mesophase formation using a dimer-solvent model with phase behaviour representative of surfactant-water systems. We use an orientational order parameter to characterize systematically the appearance of mesophases. We find the process is diffusion controlled, and the appearance of mesophases is governed adiabatically by the equilibrium phase diagram from the earliest point at which the orientational order parameter can reliably distinguish between mesophases, when only a few repeat spacings of the mesophase microstructures are present. In real systems, such a stage would correspond to times of the order of a few microseconds after the initial contact.

Dimerization↗

PubMed2005

The fundamental constants and theory.

The Committee on Data for Science and Technology has recently recommended a new self-consistent set of values of basic constants and conversion factors of physics and chemistry. These values are based on a least-squares analysis that takes into account all of the latest relevant experimental and theoretical information in a consistent framework. Theory plays a role, because the experimental data are compared to the corresponding theoretical predictions which are functions of the fundamental constants. The best values of the constants are taken to be those that give the best agreement between the data and these predictions, in the least-squares sense. An overview of the calculations that influence the recommended values of the constants will be given.

Algorithms↗

PubMed2001

Composite membrane deformation on the mesoscopic length scale.

The physics of soft materials can be investigated using nuclear spin-lattice relaxation, which depends on the spectral densities of motion in the MHz range. For the first time, NMR relaxation has been used to study influences of the acyl length, polar head groups, a cosurfactant, and cholesterol on the viscoelastic properties of membrane lipids. The results imply the concept of elastic deformation is relevant on lengths approximately equal to the bilayer thickness and less, involving a broad spectrum of collective modes which contribute to the forces between lipid bilayers.

Biophysics↗

PubMed2005

Linkage mapping bovine EST-based SNP.

BACKGROUND: Existing linkage maps of the bovine genome primarily contain anonymous microsatellite markers. These maps have proved valuable for mapping quantitative trait loci (QTL) to broad regions of the genome, but more closely spaced markers are needed to fine-map QTL, and markers associated with genes and annotated sequence are needed to identify genes and sequence variation that may explain QTL. RESULTS: Bovine expressed sequence tag (EST) and bacterial artificial chromosome (BAC)sequence data were used to develop 918 single nucleotide polymorphism (SNP) markers to map genes on the bovine linkage map. DNA of sires from the MARC reference population was used to detect SNPs, and progeny and mates of heterozygous sires were genotyped. Chromosome assignments for 861 SNPs were determined by twopoint analysis, and positions for 735 SNPs were established by multipoint analyses. Linkage maps of bovine autosomes with these SNPs represent 4585 markers in 2475 positions spanning 3058 cM. Markers include 3612 microsatellites, 913 SNPs and 60 other markers. Mean separation between marker positions is 1.2 cM. New SNP markers appear in 511 positions, with mean separation of 4.7 cM. Multi-allelic markers, mostly microsatellites, had a mean (maximum) of 216 (366) informative meioses, and a mean 3-lod confidence interval of 3.6 cM Bi-allelic markers, including SNP and other marker types, had a mean (maximum) of 55 (191) informative meioses, and were placed within a mean 8.5 cM 3-lod confidence interval. Homologous human sequences were identified for 1159 markers, including 582 newly developed and mapped SNP. CONCLUSION: Addition of these EST- and BAC-based SNPs to the bovine linkage map not only increases marker density, but provides connections to gene-rich physical maps, including annotated human sequence. The map provides a resource for fine-mapping quantitative trait loci and identification of positional candidate genes, and can be integrated with other data to guide and refine assembly of bovine genome sequence. Even after the bovine genome is completely sequenced, the map will continue to be a useful tool to link observable phenotypes and animal genotypes to underlying genes and molecular mechanisms influencing economically important beef and dairy traits.

Alleles↗

PubMed1991

Improvement of lesion detection by echographic image processing: signal-to-noise-ratio imaging.

Signal-to-noise-ratio (SNR) images were constructed by a sliding window technique. Theoretical derivations of the first order statistical properties of SNR images are given for the case of intensity coding of the original images for low number densities and for the limit case of fully developed speckle. The original images were obtained by realistic simulations of backscattering by homogeneous media, while using a range of number densities of the scatterers (isotropic scattering). The SNR imaging method is illustrated by results obtained from simulated scattering media containing a lesion that is contrasting in reflectivity level or in number density of the scatterers. A considerable improvement in lesion detection is obtained if the primary difference from the background speckle is due to a different number density of the scatterers within the lesion.

Image Processing, Computer-Assisted↗