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Showing papers by "University of Washington published in 1991"


Journal ArticleDOI
24 Oct 1991-Nature
TL;DR: In this article, the authors describe a photovoltaic cell, created from low-to medium-purity materials through low-cost processes, which exhibits a commercially realistic energy-conversion efficiency.
Abstract: THE large-scale use of photovoltaic devices for electricity generation is prohibitively expensive at present: generation from existing commercial devices costs about ten times more than conventional methods1. Here we describe a photovoltaic cell, created from low-to medium-purity materials through low-cost processes, which exhibits a commercially realistic energy-conversion efficiency. The device is based on a 10-µm-thick, optically transparent film of titanium dioxide particles a few nanometres in size, coated with a monolayer of a charge-transfer dye to sensitize the film for light harvesting. Because of the high surface area of the semiconductor film and the ideal spectral characteristics of the dye, the device harvests a high proportion of the incident solar energy flux (46%) and shows exceptionally high efficiencies for the conversion of incident photons to electrical current (more than 80%). The overall light-to-electric energy conversion yield is 7.1-7.9% in simulated solar light and 12% in diffuse daylight. The large current densities (greater than 12 mA cm-2) and exceptional stability (sustaining at least five million turnovers without decomposition), as well as the low cost, make practical applications feasible.

26,457 citations


Journal ArticleDOI
TL;DR: In this paper, the authors defined clinically significant change as the extent to which therapy moves someone outside the range of the dysfunctional population or within the ranges of the functional population, and proposed a reliable change index (RC) to determine whether the magnitude of change for a given client is statistically reliable.
Abstract: In 1984, Jacobson, Follette, and Revenstorf defined clinically significant change as the extent to which therapy moves someone outside the range of the dysfunctional population or within the range of the functional population. In the present article, ways of operationalizing this definition are described, and examples are used to show how clients can be categorized on the basis of this definition. A reliable change index (RC) is also proposed to determine whether the magnitude of change for a given client is statistically reliable. The inclusion of the RC leads to a twofold criterion for clinically significant change.

7,653 citations


Journal ArticleDOI
TL;DR: The Neuropathology Task Force of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) has developed a practical and standardized neuropathology protocol for the postmortem assessment of dementia and control subjects, which provides neuropathologic definitions of such terms as “definite Alzheimer's disease” (AD), “probable AD,” “possible AD” and “normal brain” to indicate levels of diagnostic certainty.
Abstract: The Neuropathology Task Force of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) has developed a practical and standardized neuropathology protocol for the postmortem assessment of dementia and control subjects. The protocol provides neuropathologic definitions of such terms as "definite Alzheimer's disease" (AD), "probable AD," "possible AD," and "normal brain" to indicate levels of diagnostic certainty, reduce subjective interpretation, and assure common language. To pretest the protocol, neuropathologists from 15 participating centers entered information on autopsy brains from 142 demented patients clinically diagnosed as probable AD and on eight nondemented patients. Eighty-four percent of the dementia cases fulfilled CERAD neuropathologic criteria for definite AD. As increasingly large numbers of prospectively studied dementia and control subjects are autopsied, the CERAD neuropathology protocol will help to refine diagnostic criteria, assess overlapping pathology, and lead to a better understanding of early subclinical changes of AD and normal aging.

4,837 citations


Journal ArticleDOI
TL;DR: These examinations in CHS permit evaluation of CVD risk factors in older adults, particularly in groups previously under-represented in epidemiologic studies, such as women and the very old.

3,631 citations


Journal ArticleDOI
TL;DR: In this article, an issue-contingent model containing a new set of variables called moral intensity was proposed, and the authors argue that moral intensity influences every component of moral decision making and behavior.
Abstract: Existing theoretical models of individual ethical decision making in organizations place little or no emphasis on characteristics of the ethical issue itself. This article (a) proposes an issue-contingent model containing a new set of variables called moral intensity; (b) using concepts, theory, and evidence derived largely from social psychology, argues that moral intensity influences every component of moral decision making and behavior; (c) offers four research propositions: and (d) discusses implications of the theory.

3,540 citations


Journal ArticleDOI
TL;DR: There has been much recent interest in Bayesian image analysis, including such topics as removal of blur and noise, detection of object boundaries, classification of textures, and reconstruction of two- or three-dimensional scenes from noisy lower-dimensional views as mentioned in this paper.
Abstract: There has been much recent interest in Bayesian image analysis, including such topics as removal of blur and noise, detection of object boundaries, classification of textures, and reconstruction of two- or three-dimensional scenes from noisy lower-dimensional views. Perhaps the most straightforward task is that of image restoration, though it is often suggested that this is an area of relatively minor practical importance. The present paper argues the contrary, since many problems in the analysis of spatial data can be interpreted as problems of image restoration. Furthermore, the amounts of data involved allow routine use of computer intensive methods, such as the Gibbs sampler, that are not yet practicable for conventional images. Two examples are given, one in archeology, the other in epidemiology. These are preceded by a partial review of pixel-based Bayesian image analysis.

3,255 citations


Journal ArticleDOI
TL;DR: Subjects who received dialectical behavior therapy had fewer incidences of parasuicide and less medically severe parasuicides, were more likely to stay in individual therapy, and had fewer inpatient psychiatric days.
Abstract: A randomized clinical trial was conducted to evaluate the effectiveness of a cognitive-behavioral therapy, ie, dialectical behavior therapy, for the treatment of chronically parasuicidal women who met criteria for borderline personality disorder. The treatment lasted 1 year, with assessment every 4 months. The control condition was "treatment as usual" in the community. At most assessment points and during the entire year, the subjects who received dialectical behavior therapy had fewer incidences of parasuicide and less medically severe parasuicides, were more likely to stay in individual therapy, and had fewer inpatient psychiatric days. There were no between-group differences on measures of depression, hopelessness, suicide ideation, or reasons for living although scores on all four measures decreased throughout the year.

1,979 citations




Journal ArticleDOI
TL;DR: Using data from a clinical trial of therapy for back pain, it is shown that reproducibility should generally be quantified with the intraclass correlation coefficient rather than the more common Pearson r.r. coefficient, and that reproduction by retest at one-to-two week intervals may result in more realistic estimates of the variability to be observed among control subjects in a longitudinal study.

1,363 citations


Journal Article
TL;DR: It is argued that an early step in tumor progression is one that induces a mutator phenotype, and an increased mutation rate in tumors could be the basis for the multiple mutations that characterize many cancers.
Abstract: There is increasing evidence that the pathogenesis of cancer proceeds by sequential steps from normal cells to premalignant foci to localized tumors to invasive tumors and to metastatic lesions. The concept of stages of tumor progression was initially analyzed by Foulds (1), and a model for tumor progression based on genetic instability and clonal selection has been pro posed by Nowell (2). Individual steps in tumor progression have been operationally delineated in mouse skin by the responses of cells to different chemicals (3). A progression of phenotypic changes has been described in human tumors, the anatomical localization of which has made it feasible to obtain serial biopsies (2, 4). Sequential somatic chromosomal abnormalities have been reported in human cancers including malignant mel anoma (5), colon cancer (6), gliomas (7), adenocarcinoma of the esophagus (8), and small cell carcinomas of the lung (9). In addition, a multiplicity of different mutations has been carefully documented in human breast cancer (10). The dilemma is that there are too many mutations in human tumors. In this perspective, I will consider the relationships between mutation rates and cancer. At least two mutations are required to account for the chromosomal changes observed in certain human inherited diseases (11). An analysis of the literature indicates that the spontaneous mutation rate in cells is of sufficient magnitude to account for a two mutation hypothesis for the initiation of cancer. However, a larger number of mu tations are observed in many human tumors. The spontaneous mutation rate in somatic cells is not sufficient to account for these multiple mutations. If the multiple mutations in tumors are causally associated with and not just an accompaniment of cancer, then I argue that an early step in tumor progression is one that induces a mutator phenotype. An increased mutation rate in tumors could be the basis for the multiple mutations that characterize many cancers.

Journal ArticleDOI
TL;DR: In this article, an artificial neural network (ANN) approach is presented for electric load forecasting, which is used to learn the relationship among past, current and future temperatures and loads.
Abstract: An artificial neural network (ANN) approach is presented for electric load forecasting. The ANN is used to learn the relationship among past, current and future temperatures and loads. In order to provide the forecasted load, the ANN interpolates among the load and temperature data in a training data set. The average absolute errors of the 1 h and 24 h-ahead forecasts in tests on actual utility data are shown to be 1.40% and 2.06%, respectively. This compares with an average error of 4.22% for 24 h ahead forecasts with a currently used forecasting technique applied to the same data. >

Journal ArticleDOI
TL;DR: This paper develops for the first time a rigorous algorithmic procedure for determining a robust decision policy in response to any weighting of the scenarios.
Abstract: A common approach in coping with multiperiod optimization problems under uncertainty where statistical information is not really enough to support a stochastic programming model, has been to set up and analyze a number of scenarios. The aim then is to identify trends and essential features on which a robust decision policy can be based. This paper develops for the first time a rigorous algorithmic procedure for determining such a policy in response to any weighting of the scenarios. The scenarios are bundled at various levels to reflect the availability of information, and iterative adjustments are made to the decision policy to adapt to this structure and remove the dependence on hindsight.

Journal ArticleDOI
TL;DR: The shoulders in which the repaired cuff was intact at the time of follow-up had better function during activities of daily living and a better range of active flexion compared with the shoulders that had a large recurrent defect.
Abstract: We evaluated the results of 105 operative repairs of tears of the rotator cuff of the shoulder in eighty-nine patients at an average of five years postoperatively. We correlated the functional result with the integrity of the cuff, as determined by ultrasonography. Eighty per cent of the repairs of a tear involving only the supraspinatus tendon were intact at the time of the most recent follow-up, while more than 50 per cent of the repairs of a tear involving more than the supraspinatus tendon had a recurrent defect. Older patients and patients in whom a larger tear had been repaired had a greater prevalence of recurrent defects. At the time of the most recent follow-up, most of the patients were more comfortable and were satisfied with the result of the repair, even when they had sonographic evidence of a recurrent defect. The shoulders in which the repaired cuff was intact at the time of follow-up had better function during activities of daily living and a better range of active flexion (129 +/- 20 degrees compared with 71 +/- 41 degrees) compared with the shoulders that had a large recurrent defect. Similar correlations were noted for the range of active external and internal rotation and for strength of flexion, abduction, and internal rotation. In the shoulders in which the cuff was not intact, the degree of functional loss was related to the size of the recurrent defect.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal ArticleDOI
TL;DR: In this paper, the authors extended the empirical expression of Sack et al. to allow the calculation of Fe-redox equilibrium in a natural silicate liquid as a function of composition, temperature, fo2 and pressure; a more formal thermodynamic expression is presented in the Appendix.
Abstract: Ultrasonic longitudinal acoustic velocities in oxidized silicate liquids indicate that the pressure derivative of the partial-molar volume of Fe2O3 is the same in iron-rich alkali-, alkaline earth- and natural silicate melt compositions at 1 bar. The dV/dP for multicomponent silicate liquids can be expressed as a linear combination of partial-molar constants plus a positive excess term for Na2O−Al2O3 mixing. Partial-molar properties for FeO and Fe2O3 components allow extension of the empirical expression of Sack et al. (1980) to permit the calculation of Fe-redox equilibrium in a natural silicate liquid as a function of composition, temperature, fo2 and pressure; a more formal thermodynamic expression is presented in the Appendix. The predicted equilibrium fo2 of natural silicate melts, of fixed oxygen content, closely parallels that defined by the metastable assemblage fayalite+magnetite+β-quartz (FMQ), in pressure-temperature space. A silicate melt initially equilibrated at 3 GPa and FMQ, will remain within approximately 0.5 log10 units of FMQ during its closed-system ascent. Thus, for magmas closed to oxygen, iron-redox equilibrium in crystal-poor pristine glassy lavas represents an excellent probe of the relative oxidation state of their source regions.

Journal ArticleDOI
TL;DR: It is suggested that the internal organization of phonetic categories around prototypic members is an ontogenetically early, species-specific, aspect of the speech code.
Abstract: Many perceptual categories exhibit internal structure in which category prototypes play an important role. In the four experiments reported here, the internal structure of phonetic categories was explored in studies involving adults, infants, and monkeys. In Experiment 1, adults rated the category goodness of 64 variants of the vowel /i/ on a scale from 1 to 7. The results showed that there was a certain location in vowel space where listeners rated the /i/ vowels as best instances, or prototypes. The perceived goodness of Iii vowels declined systematically as stimuli were further removed from the prototypic Iii vowel. Experiment 2 went beyond this initial demonstration and examined the effect of speech prototypes on perception. Either the prototypic or a nonprototypic IM vowel was used as the referent stimulus and adults’ generalization to other members of the category was examined. Results showed that the typicality of the speech stimulus strongly affected perception. When the prototype of the category served as the referent vowel, there was significantly greater generalization to other /i/ vowels, relative to the situation in which the nonprototype served as the referent. The notion of aperceptual magnet was introduced. The prototype of the category functioned like a perceptual magnet for other category members; it assimilated neighboring stimuli, effectively pulling them toward the prototype. In Experiment 3, the ontogenetic origins of the perceptual magnet effect were explored by testing 6-month-old infants. The results showed that infants’ perception of vowels was also strongly affected by speech prototypes. Infants showed significantly greater generalization when the prototype of the vowel category served as the referent; moreover, their responses were highly correlated with those of adults. In Experiment 4, Rhesus monkeys were tested to examine whether or not the prototype’s magnet effect was unique to humans. The animals did not provide any evidence of speech prototypes; they did not exhibit the magnet effect. It is suggested that the internal organization of phonetic categories around prototypic members is an ontogenetically early, species-specific, aspect of the speech code

Journal ArticleDOI
26 Jul 1991-Science
TL;DR: A hypothesis is proposed explaining how phosphatases might act synergistically with the kinases to elicit a full physiological response, without regard to the state of phosphorylation of the target proteins.
Abstract: Protein tyrosine phosphatases (PTPs) represent a diverse family of enzymes that exist as integral membrane and nonreceptor forms. The PTPs, with specific activities in vitro 10 to 1000 times greater than those of the protein tyrosine kinases would be expected to effectively control the amount of phosphotyrosine in the cell. They dephosphorylate tyrosyl residues in vivo and take part in signal transduction and cell cycle regulation. Most of the transmembrane forms, such as the leukocyte common antigen (CD45), contain two conserved intracellular catalytic domains; but their external segments are highly variable. The structural features of the transmembrane forms suggest that these receptor-linked PTPs are capable of transducing external signals; however, the ligands remain unidentified. A hypothesis is proposed explaining how phosphatases might act synergistically with the kinases to elicit a full physiological response, without regard to the state of phosphorylation of the target proteins.


Journal ArticleDOI
TL;DR: The role of bacteria in the initiation of periodontitis is well-documented and the end result, destruction of the alveolar bone and periodontal connective tissue, is readily observed; but the events occurring between these two points in time remain obscure and are the focus of this paper.
Abstract: The role of bacteria in the initiation of periodontitis is well-documented and the end result, destruction of the alveolar bone and periodontal connective tissue, is readily observed; but the events occurring between these two points in time remain obscure and are the focus of this paper. Bacteria induce tissue destruction indirectly by activating host defense cells, which in turn produce and release mediators that stimulate the effectors of connective tissue breakdown. Components of microbial plaque have the capacity to induce the initial infiltrate of inflammatory cells including lymphocytes, macrophages, and PMNs. Microbial components, especially lipopolysaccharide (LPS), have the capacity to activate macrophages to synthesize and secrete a wide array of molecules including the cytokines interleukin-1 (IL-1) and tumor-necrosis factor-alpha (TNF-alpha), prostaglandins, especially PGE2, and hydrolytic enzymes. Likewise, bacterial substances activate T lymphocytes and they produce IL-1 and lymphotoxin (LT), a molecule having properties very similar to TNF-alpha. These cytokines manifest potent proinflammatory and catabolic activities, and play key roles in periodontal tissue breakdown. They induce fibroblasts and macrophages to produce neutral metalloproteinases such as procollagenase and prostromelysin, the serine proteinase urokinase-type plasminogen activator (u-PA), tissue inhibitor of metalloproteinase (TIMP), and prostaglandins, u-PA converts plasminogen into plasmin, which can activate neutral metalloproteinase proenzymes, and these enzymes degrade the extracellular matrix components. TIMP inactivates the active enzymes and thereby blocks further tissue degradation. Several amplification and suppression mechanisms are involved in the process. While LPS activates macrophages to produce IL-1, IL-1 is autostimulatory and can therefore amplify and perpetuate its own production. Interferon-gamma (INF-gamma) suppresses autostimulation, but it enhances LPS-induced IL-1 production. PGE2 exerts a control over the whole process by suppressing production of both IL-1 and TNF-alpha. Furthermore, the activated cells produce an IL-1 receptor antagonist that binds to the IL-1 receptor but does not induce the biologic consequences of IL-1 binding. Other cytokines such as transforming growth factor-beta (TGF-beta) suppress production of metalloproteinases and u-PA. Thus the progression and extent of tissue degradation is likely to be determined in major part by relative concentrations and half-life of IL-1, TNF-alpha, and related cytokines, competing molecules such as the IL-1 receptor antagonist, and suppressive molecules such as TGF-beta and PGE2. These molecules control levels of latent and active metalloproteinase and u-PA, and the availability and concentration of TIMP determines the extent and duration of degradative activity.

Journal ArticleDOI
18 Dec 1991-JAMA
TL;DR: In this article, Carotid endarterectomy was used to prevent subsequent cerebral ischemia in men with ischemic symptoms in the distribution of significant (>50%) ipsilateral internal carotid artery stenosis.
Abstract: Objective. —To determine whether carotid endarterectomy provides protection against subsequent cerebral ischemia in men with ischemic symptoms in the distribution of significant (>50%) ipsilateral internal carotid artery stenosis. Design. —Prospective, randomized, multicenter trial. Setting. —Sixteen university-affiliated Veterans Affairs medical centers. Patients. —Men who presented within 120 days of onset of symptoms that were consistent with transient ischemic attacks, transient monocular blindness, or recent small completed strokes between July 1988 and February 1991. Among 5000 patients screened, 189 individuals were randomized with angiographic internal carotid artery stenosis greater than 50% ipsilateral to the presenting symptoms. Forty-eight eligible patients who refused entry were followed up outside of the trial. Outcome Measures. —Cerebral infarction or crescendo transient ischemic attacks in the vascular distribution of the original symptoms or death within 30 days of randomization. Intervention. —Carotid endarterectomy plus the best medical care (n = 91) vs the best medical care alone (n=98). Results. —At a mean follow-up of 11.9 months, there was a significant reduction in stroke or crescendo transient ischemic attacks in patients who received carotid endarterectomy (7.7%) compared with nonsurgical patients (19.4%), or an absolute risk reduction of 11.7% (P=.011). The benefit of surgery was more profound in patients with internal carotid artery stenosis greater than 70% (absolute risk reduction, 17.7%;P=.004). The benefit of surgery was apparent within 2 months after randomization, and only one stroke was noted in the surgical group beyond the 30-day perioperative period. Conclusions. —For a selected cohort of men with symptoms of cerebral or retinal ischemia in the distribution of a high-grade internal carotid artery stenosis, carotid endarterectomy can effectively reduce the risk of subsequent ipsilateral cerebral ischemia. The risk of cerebral ischemia in this subgroup of patients is considerably higher than previously estimated. (JAMA. 1991;266:3289-3294)

Journal ArticleDOI
TL;DR: The magnetic susceptibility of loess and paleosols in central China represents a proxy climate index closely related to past changes of precipitation and vegetation, and thus to summer monsoon intensity as discussed by the authors.

Book
01 Jan 1991
TL;DR: In this paper, a monograph on applications of mathematics is intended for students of mathematics, engineering and the sciences, which is intended to provide the basis for the reader to go on to solve new problems.
Abstract: This accessible work is intended to be used as a textbook and as a reference on singular perturbation methods and their uses in applications. It offers a constructive approach which is primarily analytical, but which is also related to current work in numerical computation. The applications discussed in the book are intended to provide the basis for the reader to go on to solve new problems. This monograph on applications of mathematics is intended for students of mathematics, engineering and the sciences.

Journal ArticleDOI
01 Aug 1991-Tellus A
TL;DR: In this paper, a three-dimensional global model for estimating the SO 4 = aerosol mass concentration, along with previously-acquired information on the scattering and back-scattering coefficients per unit mass concentration are presented.
Abstract: Anthropogenic sulfate (SO 4 = ) aerosol particles play two potential roles in the radiative climate of the earth. In cloud-free air, SO 4 = particles scatter sunlight, some of which is lost to space, thereby reducing solar irradiance at the ground. The same particles can act as cloud condensation nuclei (CCN), the number concentration of which is an important determinant of cloud albedo. This albedo effect, in turn, also influences incoming short-wave solar radiation. Development of a three-dimensional global model for estimating the SO 4 = aerosol mass concentration, along with previously-acquired information on the scattering and back-scattering coefficients per unit mass concentration allow calculation of the effects of anthropogenic SO 4 = aerosol on clear-sky optical depth. Subsequently, this can be used to estimate the change in hemispheric and global average reflected solar radiation. The conclusion is that the change of reflected solar flux due to anthropogenic SO 4 = averaged over the Northern Hemisphere is ca. − 1.1 Wm -2 , which is comparable but opposite in sign to the present-day radiative forcing by anthropogenic CO 2 , + 1.5 Wm -2 . Because of the spatial variability of the anthropogenic SO 4 = distribution, its meteorological effects must be studied regionally. That is, global models with regional resolution and regional data are required. Unlike the direct effect on solar irradiance, the relationship of CCN number concentration to mass concentration is not known. Thus it is not yet possible to make quantitatively reliable statements about anthropogenic forcing of cloud albedo, although there is qualitative evidence that the CCN effect may also be substantial. DOI: 10.1034/j.1600-0870.1991.00013.x

Journal ArticleDOI
TL;DR: The results of this study support the concept that endogenous bFGF is the major mitogen controlling the growth of vascular smooth muscle cells following injury, and may have implications for the observed failure of endarterectomy and angioplasty procedures.
Abstract: Proliferation of smooth muscle cells (SMCs) represents an important event in vascular lesion formation. Despite the common belief that growth factors contribute to the development of the atherosclerotic plaque, until now there has been no direct evidence for a role of mitogens in the development of arterial lesions. Balloon catheter injury of the rat carotid artery is accompanied by death of medial SMCs and is typically followed by proliferation of SMCs with subsequent formation of an intimal lesion. Our hypothesis is that injury causes mitogens to be released from dead cells, which then stimulate cell proliferation. One such mitogen that may be important in this process is basic fibroblast growth factor (bFGF), which can be detected immunocytochemically in SMCs and endothelial cells of adult rat carotid arteries. Systemic injection of a neutralizing antibody against bFGF prior to balloon catheterization significantly decreased the induced SMC proliferation by approximately 80%. The intimal lesion that developed within 8 days after injury, however, was not significantly reduced. The results of this study support the concept that endogenous bFGF is the major mitogen controlling the growth of vascular smooth muscle cells following injury. These data may have implications for the observed failure of endarterectomy and angioplasty procedures.

Journal ArticleDOI
TL;DR: It is suggested that tests for delayed recall may be particularly useful in the early detection of Alzheimer's disease and should be considered in screening batteries for dementia in community surveys.
Abstract: • The present study was designed to determine which of the memory tasks included in the CERAD ( C onsortium to E stablish a R egistry for A lzheimer's D isease) neuropsychological battery best differentiate patients with early Alzheimer's disease from cognitively normal elderly control subjects and also best distinguish between the various levels of severity of the dementia process. A sample of CERAD patients with Alzheimer's disease was stratified by disease severity into those with mild, moderate, or severe dementia and matched with control subjects for sex, age, and education. Using multivariate procedures and cutting scores, the efficacy of each memory measure in distinguishing between these groups and control subjects was determined. The test for delayed recall was found to be the best overall discriminatory measure. The other tests of memory, ie, immediate recall, intrusion errors, and recognition memory, had poor overall discriminability. None of the CERAD memory measures were found to be particularly powerful in staging the severity of dementia. These findings suggest that tests for delayed recall may be particularly useful in the early detection of Alzheimer's disease and should be considered in screening batteries for dementia in community surveys.


Journal ArticleDOI
01 Jan 1991-Spine
TL;DR: The findings emphasize the importance of adopting a broader approach to the multifaceted problem of back complaints in industry and help explain why past prevention efforts focusing on purely physical factors have been unsuccessful.
Abstract: A longitudinal, prospective study was conducted on 3,020 aircraft employees to identify risk factors for reporting acute back pain at work. The premorbid data included individual physical, psychosocial, and workplace factors. During slightly more than 4 years of follow-up, 279 subjects reported back problems. Other than a history of current or recent back problems, the factors found to be most predictive of subsequent reports in a multivariate model were work perceptions and certain psychosocial responses identified on the Minnesota Multiphasic Personality Inventory (MMPI). Subjects who stated that they "hardly ever" enjoyed their job tasks were 2.5 times more likely to report a back injury (P = 0.0001) than subjects who "almost always" enjoyed their job tasks. The quintile of subjects scoring highest on Scale-3 (Hy) of the MMPI were 2.0 times more likely to report a back injury (P = 0.0001) than subjects with the lowest scores. The multivariate model, including job task enjoyment, MMPI Scale-3, and history of back treatment, revealed that subjects in the highest risk group had 3.3 times the number of reports in the lowest risk group. These findings emphasize the importance of adopting a broader approach to the multifaceted problem of back complaints in industry and help explain why past prevention efforts focusing on purely physical factors have been unsuccessful.

Journal ArticleDOI
TL;DR: An automated code has been developed, in which curved-wave effects are treated exactly in terms of effective backscattering amplitudes, inelastic losses and self-energy shifts are incorporated with use of a Hedin-Lundqvist self- energy, an automated relativistic overlapping-atom muffin-tin potential is used, and the energy threshold is estimated from electron-gas theory.
Abstract: The most important elements of {ital ab} {ital initio} calculations of x-ray-absorption fine structure (XAFS) are studied. To obtain accurate results without {ital ad} {ital hoc} adjustable parameters, we find it essential to include (i) curved-wave effects, (ii) a complex, energy-dependent self-energy, (iii) an approximate molecular potential, and (iv) a fixed energy reference for the photoelectron wave number. Based on these findings, an automated code has been developed for {ital ab} {ital initio} calculations of single-scattering XAFS, in which curved-wave effects are treated exactly in terms of effective backscattering amplitudes, inelastic losses and self-energy shifts are incorporated with use of a Hedin-Lundqvist self-energy, an automated relativistic overlapping-atom muffin-tin potential is used, and the energy threshold is estimated from electron-gas theory. The efficiency of the code is made possible by analytic expressions for the Hedin-Lundqvist self-energy. This code replaces existing tables of XAFS phases and scattering amplitudes and yields reliable theoretical XAFS standards for arbitrary pairs of atoms throughout the Periodic Table ({ital Z}{le}94). These results are comparable to those from self-consistent calculations and are valid to within about 20 eV of the absorption edge. Comparisons with experiment are presented for Cu, Ge, Pt, Br{sub 2}, and GeCl{sub 4}. The calculatedmore » XAFS amplitudes are found to be accurate to within 15%; XAFS phases are accurate to within 0.2 rad; and nearest-neighbor distances are typically accurate to within 0.02 A.« less

Journal ArticleDOI
TL;DR: In this paper, the authors investigate the geochemistry of these metals by interpreting measurements from anoxic basins and sediment porewaters, and they estimate that the area of ocean sediment at present overlain by anoxic and near-anoxic water is accumulating 25 ± 15% and 8 ± 5% of the river influx of Mo and V, respectively.

Journal ArticleDOI
TL;DR: Individual drinking patterns and the perceived typical drinking patterns of close friends and reference groups were assessed in two different studies with college students and it was interpreted that reports of others' drinking were exaggerated.
Abstract: Individual drinking patterns and the perceived typical drinking patterns of close friends and reference groups were assessed in two different studies with college students. In both studies virtually all students reported that their friends drank more than they did. These effects were found across different levels of individual drinking, within different types of samples, across gender of subjects and with different types of questionnaire assessment. In addition, students' estimates of typical or average drinking within their own social living groups were significantly higher than average drinking within the group estimated from self-reports. Because of the consistent, asymmetrical pattern of reports of self and other drinking, it was interpreted that reports of others' drinking were exaggerated. These biases were particularly evident within organized social groups (i.e., fraternities and sororities) but were minimal in reference to "students in general" or "people in general." Results are discussed in terms of cognitive and motivational factors that potentially could promote or excuse excessive drinking practices among college students.