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Showing papers by "University of Rhode Island published in 1993"


Journal ArticleDOI
TL;DR: The Fundamentals of Statistical Signal Processing: Estimation Theory as mentioned in this paper is a seminal work in the field of statistical signal processing, and it has been used extensively in many applications.
Abstract: (1995). Fundamentals of Statistical Signal Processing: Estimation Theory. Technometrics: Vol. 37, No. 4, pp. 465-466.

14,342 citations


Journal ArticleDOI
TL;DR: The authors summarizes research on self-initiated and professionally-trained individuals who intentionally change addictive behaviors with and without treatment, using self-training and self-awareness as a tool.
Abstract: How people intentionally change addictive behaviors with and without treatment is not well understood by behavioral scientists. This article summarizes research on self-initiated and professionally...

1,526 citations


Journal ArticleDOI
01 Jul 1993-Nature
TL;DR: The ice-core record of local temperature, dust accumulation and air composition at Vostok station, Antarctica, now extends back to the penultimate glacial period (∼140-200 kyr ago) and the end of the preceding interglacial as discussed by the authors.
Abstract: The ice-core record of local temperature, dust accumulation and air composition at Vostok station, Antarctica, now extends back to the penultimate glacial period (∼140–200 kyr ago) and the end of the preceding interglacial. This yields a new glaciological timescale for the whole record, which is consistent with ocean records. Temperatures at Vostok appear to have been more uniformly cold in the penultimate glacial period than in the most recent one. Concentrations of CO2 and CH4 correlate well with temperature throughout the record.

555 citations


Journal ArticleDOI
TL;DR: If traditional scientific criteria relevant to quantitative studies are used to critique qualitative methods, the development and acceptance of this paradigm-transcending research will be hindered.
Abstract: The three criteria of credibility, fittingness, and auditability have been focused on in the hope of facilitating the critique of qualitative research. Once criteria that are appropriate to qualitative methodologies are developed, the scientific merit of these research studies can truly be appreciated. If traditional scientific criteria relevant to quantitative studies are used to critique qualitative methods, the development and acceptance of this paradigm-transcending research will be hindered.

440 citations


Journal ArticleDOI
TL;DR: The central characteristics, three major approaches to action research that exist today and how action research has been used and can be used in nursing are addressed.
Abstract: Action research has enjoyed increasing popularity across a wide variety of disciplines including nursing. Action research was designed specifically to bridge the gap between theory, research and practice and incorporates both humanistic and naturalistic scientific methods. As such, action research is a highly compelling method for nursing. However, action research does not easily lend itself to definition. A variety of approaches, definitions and uses have emerged since it was created by Kurt Lewin and have given rise to much debate within social and behavioural sciences. This confusion has carried over into nursing literature without any systematic identification of or debate about the core characteristics of action research or the multitude of approaches or uses that have come to be associated with this method. Thus this paper addresses the central characteristics, three major approaches to action research that exist today and how action research has been used and can be used in nursing.

396 citations


Journal ArticleDOI
TL;DR: Somma is a single-operator multiparameter metabolic analyzer as discussed by the authors that combines high accuracy and precision (± 1.5 μmol/kg for total carbon dioxide ≥ 2000 μmol /kg) with a high rate of analysis.

353 citations


Journal ArticleDOI
TL;DR: The Pathways to Change system (PTC) is an expert system intervention for smoking cessation that demonstrates the efficacy of this intervention in a general population, with cessation rates of 22 to 26%.

314 citations


Journal ArticleDOI
TL;DR: In this article, the authors examined the distribution of surface pigment fields in the entire southern ocean over a seasonal cycle and identified the occurrence of intense phytoplankton blooms during austral summer months and during other seasons in different regions.
Abstract: Climatological data on the distribution of surface pigment fields in the entire southern ocean over a seasonal cycle are examined. The occurrence of intense phytoplankton blooms during austral summer months and during other seasons in different regions is identified and analyzed. The highest pigment concentrations are observed at high latitudes and over regions with water depths usually less than 600 m. Basin-scale pigment distribution shows a slightly asymmetric pattern of enhanced pigment concentrations about Antarctica, with enhanced concentrations extending to lower latitudes in the Atlantic and Indian sectors than in the Pacific sector. A general increase in pigment concentrations is evident from the low latitudes toward the Antarctic circumpolar region. Spatial relationships between pigment and archived geophysical data reveal significant correlation between pigment distributions and both bathymetry and wind stress, while general hemispheric scale patterns of pigment distributions are most coherent with the geostrophic flow of the Antarctic Circumpolar Current.

294 citations


Journal ArticleDOI
TL;DR: The authors unify and simplify this previous result and derive a unified expression based on the original data parameters to derive a tractable expression for the mean-squared DOA estimation error for the multiple signal classification.
Abstract: Subspace based direction-of-arrival (DOA) estimation has motivated many performance studies, but limitations such as the assumption of an infinite amount of data and analysis of individual algorithms generally exist in these performance studies. The authors have previously proposed a unified performance analysis based on a finite amount of data and achieved a tractable expression for the mean-squared DOA estimation error for the multiple signal classification (MUSIC). Min-Norm, estimation of signal parameters using rotational invariance techniques (ESPRIT), and state-space realization algorithms. However, this expression uses the singular values and vectors of a data matrix, which are obtained by the highly nonlinear transformation of the singular value decomposition (SVD). Thus the effects of the original data parameters such as numbers of sensors and snapshots, source coherence and separations were not explicitly analyzed. The authors unify and simplify this previous result and derive a unified expression based on the original data parameters. They analytically observe the effects of these parameters on the estimation error. >

286 citations


Journal ArticleDOI
TL;DR: During a 25 d Lagrangian study in May and June 1990 in the Northeast Atlantic Ocean, marine snow aggregates were collected using a novel water bottle, and the composition was determined microscopically, revealing a characteristic signature of a matrix of bacteria, cyanobacteria and autotrophic picoplankton with inter alia inclusions of the tintiniid Dictyocysta elegans and large pennate diatoms.
Abstract: During a 25 d Lagrangian study in May and June 1990 in the Northeast Atlantic Ocean, marine snow aggregates were collected using a novel water bottle, and the composition was determined microscopically. The aggregates contained a characteristic signature of a matrix of bacteria, cyanobacteria and autotrophic picoplankton with inter alia inclusions of the tintiniid Dictyocysta elegans and large pennate diatoms. The concentration of bacteria and cyanobacteria was much greater on the aggregates than when free-living by factors of 100 to 6000 and 3000 to 2 500 000, respectively, depending on depth. Various species of crustacean plankton and micronekton were collected, and the faecal pellets produced after capture were examined. These often contained the marine snow signature, indicating that these organisms had been consuming marine snow. In some cases, marine snow material appeared to dominate the diet. This implies a food-chain short cut wherby material, normally too small to be consumed by the mesozooplankton, and considered to constitute the diet of the microplankton can become part of the diet of organisms higher in the food-chain. The micronekton was dominated by the amphipod Themisto compressa, whose pellets also contained the marine snow signature. Shipboard incubation experiments with this species indicated that (1) it does consume marine snow, and (2) its gut-passage time is sufficiently long for material it has eaten in the upper water to be defecated at its day-time depth of several hundred meters. Plankton and micronekton were collected with nets to examine their vertical distribution and diel migration and to put into context the significance of the flux of material in the guts of migrants. “Gut flux” for the T. compressa population was calculated to be up to 2% of the flux measured simultaneously by drifting sediment traps and 0.6 mm) was examined photographically. A sharp concentration peak was usually encountered in the depth range 40 to 80 m which was not associated with peaks of in situ fluorescence or attenuation but was just below or at the base of the upper mixed layer. The feeding behaviour of zooplankton and nekton may influence these concentration gradients to a considerable extent, and hence affect the flux due to passive settling of marine snow aggregates.

262 citations


Journal ArticleDOI
TL;DR: The following basic minimization problem is studied: Given a DFA (deterministic FA), find a minimum equivalent FA (FA) that is Turing-complete and Turing-supervised.
Abstract: Finite automata (FA’s) are of fundamental importance in theory and in applications. The following basic minimization problem is studied: Given a DFA (deterministic FA), find a minimum equivalent no...

Journal ArticleDOI
TL;DR: Using the grounded theory method, a substantive theory of postpartum depression was developed that attempted to cope with the problem of loss of control through the four-stage process of teetering on the edge.
Abstract: Using the grounded theory method, a substantive theory of postpartum depression was developed. Data were obtained through participant observation in a postpartum depression support group over an 18-month period. In addition, 12 in-depth taped interviews were conducted with mothers who had attended the support group. Analysis of the data by the constant comparative method revealed loss of control as the basic social psychological problem. Women suffering from postpartum depression attempted to cope with the problem of loss of control through the four-stage process of teetering on the edge. The stages that emerged from the data included (a) encountering terror, (b) dying of self, (c) struggling to survive, and (d) regaining control.

Journal ArticleDOI
TL;DR: This paper presents a profile of violence toward children in the United States, based on the results from the Second National Family Violence Survey, which found the highest rates of abusive violence occurred in families located in the East.

Journal ArticleDOI
TL;DR: In this paper, les AA. proposent une analyse des portefeuilles dans le cadre de la formation des enseignants, expliquent comment les portefeilles peuvent servir a l'evaluation des programmes de formation, decrivent les characteristiques d'un portefoeille educatif and presentent la maniere dont un portefeiille se definit et se developpe.
Abstract: Les AA. proposent une analyse des portefeuilles dans le cadre de la formation des enseignants. Ils expliquent comment les portefeuilles peuvent servir a l'evaluation des programmes de formation, ils decrivent les characteristiques d'un portefeuille educatif et presentent la maniere dont un portefeuille se definit et se developpe

Journal ArticleDOI
TL;DR: This article analyzed the major, trace, and rare earth element composition of surface sediments collected from a transect across the Equator at 135°W longitude in the Pacific Ocean.

Journal ArticleDOI
TL;DR: In this article, Japanese bidders and U.S. targets increase with bidder's leverage, the bidder's ties to financial institutions through borrowings, and the depreciation of the dollar in relation to the Japanese yen.

Journal ArticleDOI
TL;DR: In the permanently stratified Pettaquamscutt estuary, 40% of the total Hg was found to be produced by methylation, sedimentation, methylation and HgO production as discussed by the authors.
Abstract: Total Hg in the permanently stratified Pettaquamscutt estuary was 40% of the total Hg. Reactive Hg (Hg,) was generally <3 pM and decreased with depth, but there is Hg, even in the anoxic bottom waters. Elemental Hg (HgO) was highest in the mixed layer and below the detection limit at depth. Demethylation is not an important source of Hg” in this estuary. Dimethylmercury was not detected. Monomethylmercury (MMHg) was near the detection limit in the mixed layer and increased rapidly in the low oxygen region. Dissolved MMHg correlated with bacteriochlorophyll pigments, suggesting that the microbial community plays an important role in MMHg production in this estuary. The overall distributions of dissolved and particulate Hg species result from the interaction with Fe and Mn redox cycling, particulate scavenging and sinking, and MMHg production in the pycnocline. The estimated rate of MMHg production from Hg, in the pycnocline region is 1.7% d-l. Hg” and MMHg are formed principally in the mixed layer and in the pycnocline region, respectively. Particulate scavenging is important, and sedimentation, methylation, and HgO production are the principal sinks for Hg,.

Journal ArticleDOI
TL;DR: The factors that affect the bioadhesion power of a polymer, the methods that permit the evaluation of a bioadhesive system and the methods for surface characterization of biomaterials are discussed.
Abstract: Pharmaceutical aspects of mucoadhesion have been the subject of great interest during recent years because mucoadhesion could be a solution for bioavailability problems that result from a too short length of stay of the pharmaceutical dosage form at the absorption site within the gastro-intestinal tract.This paper describes some aspects of bioadhesion such as mucus structure, stages of adhesion and the theories proposed that attempt to explain the adhesion mechanism. The factors that affect the bioadhesive power of a polymer, the methods that permit the evaluation of a bioadhesive system and the methods for surface characterization of biomaterials are discussed. Finally, the various polymers used and the bioadhesive systems designed for several therapeutic purposes are presented.

Journal ArticleDOI
24 Jun 1993-Nature
TL;DR: In this paper, the authors show that abundant diatom (Rhizosolenia) mats migrate vertically between surface waters and deep nitrate pools in the central North Pacific Ocean, and conclude that these mats may transport the equivalent of 50% of the new nitrogen requirements into the surface waters of the North Pacific gyre.
Abstract: PHYTOPLANKTON production in the surface waters of stratified oceans is fed mainly by nitrogen that has been recycled within the euphotic zone1. The nitrogen that is lost from surface waters as organic matter exported to the deep ocean must be balanced by inputs of new nitrogen to the upper ocean2,3. Sediment trap studies2 have shown that the 15N/14N ratio (δ15N) of the exported organic matter is higher than that of the suspended particulates, and suggest that the rich nitrate pool below the euphotic zone is the source of 'new' nitrogen for the upper ocean. Yet steep vertical concentration gradients suggest that diffusive upward transport of nitrate is extremely limited, raising the question of how the nitrate reaches the surface waters. Here we present evidence that abundant diatom (Rhizosolenia) mats migrate vertically between surface waters and deep nitrate pools in the central North Pacific Ocean. Rising mats contain significantly larger internal nitrate pools than sinking mats. Mat δ15N is similar to that of the sub-nitricline nitrate, and consistently heavier than that of near-surface particulate organic matter. We conclude that Rhizosolenia mats may transport the equivalent of 50% of the new nitrogen requirements into the surface waters of the North Pacific gyre.

Journal ArticleDOI
TL;DR: The concentrations of thirtynine elements in 324 samples show large variations in sediments down the 24.3 m length of LL44-GPC3, a piston core of pelagic clay from the central North Pacific (30°19'N, 157°49.9'W) that contains a relatively continuous record of sedimentation since the late Cretaceous.


Journal ArticleDOI
TL;DR: In this paper, a contingent choice survey based on paired comparisons is used to construct a utility index to rank sites consistent with predicting results of a hypothetical referendum based on the attributes of the sites.

Book
21 Jan 1993
TL;DR: The Two-Parent Advantage: A Two-parent Advantage for Parenting Gender, Individuality and Identity Nurturance, Discipline, and Morality Intelligence and Creativity Family, School, and Education Assertiveness and Independence Body Image, Athletics, and Fitness Intimacy, Sexuality, and Social Adjustment Child and Family Problems Family, Community, and Society Suggestions for Further Reading Developmental Implications Risk Factors Constructive Approaches Summary
Abstract: Preface The Two-Parent Advantage Father, Mother, and Infant Partners in Parenting Gender, Individuality, and Identity Nurturance, Discipline, and Morality Intelligence and Creativity Family, School, and Education Assertiveness and Independence Body Image, Athletics, and Fitness Intimacy, Sexuality, and Social Adjustment Child and Family Problems Family, Community, and Society Suggestions for Further Reading Developmental Implications Risk Factors Constructive Approaches Summary

Journal ArticleDOI
TL;DR: Results from this pilot study were consistent with prior applications of the Transtheoretical Model to the cessation of such problem behaviors as smoking and to the adoption of positive health behaviors such as exercise acquisition.
Abstract: A synergistic approach was taken to examine contraceptive use adoption for two related behaviors: pregnancy prevention and the prevention of sexually transmitted diseases (STDs), including human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS). One hundred twenty-three young adults responded to questionnaire items based on two constructs from the Trans-theoretical Model of Change, the Stages of Change and Decisional Balance, as well as other pertinent variables. In Phase 1, two Decisional Balance measures were developed: One for the prevention of pregnancy and one for disease prevention. Final versions of both measures consisted of two 10-item scales: one representing the positive aspects (PROS) and one representing the negative aspects (CONS) of contraceptive and condom use. In Phase 2, the same individuals were staged for both pregnancy and disease prevention according to their readiness to change for contraceptive and condom use. MANOVAs and ANOVAs indicated that the PROS and CONS for both measures were related to stage of change for both contraceptive and condom use. Results from this pilot study were consistent with prior applications of the Trans-theoretical Model to the cessation of such problem behaviors as smoking and to the adoption of positive health behaviors such as exercise acquisition.

Journal ArticleDOI
TL;DR: The mass-particle size distributions of up to 17 trace elements in aerosol particle samples from dust storm and non-dust storm periods were determined for three sites in or near the source regions of Chinese dust.

Journal ArticleDOI
TL;DR: It is suggested that estrogen users have a more healthy profile than do nonusers, and the prevalence of postmenopausal estrogen use appears to be substantially lower in women with natural versus surgical menopause throughout the period studied.
Abstract: Correlates and prevalence of current postmenopausal estrogen use were examined in two southeastern New England communities for the period 1981 through 1990. Data were obtained from five biennial cross-sectional household health surveys, with current use of postmenopausal estrogen determined by inspection of medication bottles. Analysis included 3,279 women aged 40-64 years, of whom 2,215 (67.6%) were postmenopausal. The prevalence of estrogen use among all postmenopausal women increased from 5.3% (95% confidence interval (CI) 3.2-7.4) in 1981-1982 to 10.9% (95% CI 7.5-14.4) in 1989-1990. Among women with surgical menopause, prevalence increased from 11.4% (95% CI 6.6-16.2) to 20.3% (95% CI 13.6-27.0), while use among women with natural menopause increased from 1.5% (95% CI 0.04-2.9) to 3.5% (95% CI 0.74-6.2). Logistic regression was used to compute age-adjusted prevalence of estrogen use according to demographic characteristics and cardiovascular risk factors. Postmenopausal estrogen use was positively associated with income, and a positive trend with education was suggested. Estrogen use was positively associated with high density lipoprotein cholesterol and was inversely associated with body mass index. Nonsmokers, women who exercised at least once per week, and women who reported having their cholesterol checked in the past year were more likely to use estrogen. These findings suggest that estrogen users have a more healthy profile than do nonusers. In addition, the prevalence of postmenopausal estrogen use appears to be substantially lower in women with natural versus surgical menopause throughout the period studied.

Journal ArticleDOI
TL;DR: In this article, the effects of various contact laws on the wave propagation behavior including wave attenuation and dispersion characteristics were compared with experimental data from dynamic photoelastic and strain gage experiments.
Abstract: The microstructural wave propagation behavior of a granular medium is modeled using the distinct element method. This technique simulates the discrete behavior of the medium by assuming that the motion of each particle may be modeled using Newtonian rigid-body mechanics with particular force-deformation and force-deformation rate contact laws. The present work provides a comparison of the effects of various contact laws on the wave propagational behaviors including wave attenuation and dispersion characteristics. Specific cases which have been studied include linear, non-linear and non-linear hysteretic force-deformation contact laws along with velocity proportional damping. Numerical results are compared with experimental data from dynamic photoelastic and strain gage experiments. Since velocity-dependent contact damping is not a reasonable model for dry cohesionless granular media, it was desired to determine if a non-linear hysteretic contact law could be used to replace the velocity damping. Results indicate that such a non-linear law does provide a damping mechanism which can predict experimental attenuation data, and that the dispersion characteristics are modeled more accurately with this hysteretic model.

Journal ArticleDOI
TL;DR: The authors show that any hyperbolic TF representation is related to both the wideband ambiguity function and a "hyperbolic ambiguity function" and are shown to be the class of all quadratic TF representations which are invariant to "Hyperbolic time-shifts" and TF scalings, operations which are important in the analysis of Doppler-invariant signals and self-similar random processes.
Abstract: The time-frequency (TF) version of the wavelet transform and the "affine" quadratic/bilinear TF representations can be used for a TF analysis with constant-Q characteristic. The paper considers a new approach to constant-Q TF analysis. A specific TF warping transform is applied to Cohen's class of quadratic TF representations, which results in a new class of quadratic TF representations with constant-Q characteristic. The new class is related to a "hyperbolic TF geometry" and is thus called the hyperbolic class (HC). Two prominent TF representations previously considered in the literature, the Bertrand P/sub 0/ distribution and the Altes-Marinovic Q-distribution, are members of the new HC. The authors show that any hyperbolic TF representation is related to both the wideband ambiguity function and a "hyperbolic ambiguity function". It is also shown that the HC is the class of all quadratic TF representations which are invariant to "hyperbolic time-shifts" and TF scalings, operations which are important in the analysis of Doppler-invariant signals and self-similar random processes. The paper discusses the definition of the HC via constant-Q warping, some signal-theoretic fundamentals of the "hyperbolic TF geometry", and the description of the HC by 2D kernel functions. Several members of the HC are considered, and a list of desirable properties of hyperbolic TF representations is given together with the associated kernel constraints. >

Journal ArticleDOI
TL;DR: A review of surface modification with beams of gas cluster ions is given in this article, where damage, implantation, and surface erosion with 5-30 kV cluster ions of Ar and CO 2 are discussed in the context of earlier results obtained at higher energies.
Abstract: A review of recent data on surface modification with beams of gas cluster ions is given. Damage, implantation, and surface erosion with 5–30 kV cluster ions of Ar and CO 2 are discussed in the context of earlier results obtained at higher energies. It is concluded that gas cluster ion beams may find new interesting applications for very shallow implantation, amorphization and surface smoothing.

Journal ArticleDOI