Showing papers by "University of Rhode Island published in 2000"

A quantitative analysis of fishing impacts on shelf-sea benthos

Abstract: 1. The effects of towed bottom-fishing gear on benthic communities is the subject of heated debate, but the generality of trawl effects with respect to gear and habitat types is poorly understood. To address this deficiency we undertook a meta-analysis of 39 published fishing impact studies. 2. Our analysis shows that inter-tidal dredging and scallop dredging have the greatest initial effects on benthic biota, while trawling has less effect. Fauna in stable gravel, mud and biogenic habitats are more adversely affected than those in less consolidated coarse sediments. 3. Recovery rate appears most rapid in these less physically stable habitats, which are generally inhabited by more opportunistic species. However, defined areas that are fished in excess of three times per year (as occurs in parts of the North Sea and Georges Bank) are likely to be maintained in a permanently altered state. 4. We conclude that intuition about how fishing ought to affect benthic communities is generally supported, but that there are substantial gaps in the available data, which urgently need to be filled. In particular, data on impacts and recovery of epifaunal structure-forming benthic communities are badly needed.

Global Carbon Sinks and Their Variability Inferred from Atmospheric O2 and δ13C

Abstract: Recent time-series measurements of atmospheric O2 show that the land biosphere and world oceans annually sequestered 1.4 ± 0.8 and 2.0 ± 0.6 gigatons of carbon, respectively, between mid-1991 and mid-1997. The rapid storage of carbon by the land biosphere from 1991 to 1997 contrasts with the 1980s, when the land biosphere was approximately neutral. Comparison with measurements of δ13CO2 implies an isotopic flux of 89 ± 21 gigatons of carbon per mil per year, in agreement with model- and inventory-based estimates of this flux. Both the δ13C and the O2 data show significant interannual variability in carbon storage over the period of record. The general agreement of the independent estimates from O2and δ13C is a robust signal of variable carbon uptake by both the land biosphere and the oceans.

Real-Case Simulations of Hurricane-Ocean Interaction Using A High-Resolution Coupled Model: Effects on Hurricane Intensity

Abstract: In order to investigate the effect of tropical cyclone‐ocean interaction on the intensity of observed hurricanes, the GFDL movable triply nested mesh hurricane model was coupled with a high-resolution version of the Princeton Ocean Model. The ocean model had 1 /68 uniform resolution, which matched the horizontal resolution of the hurricane model in its innermost grid. Experiments were run with and without inclusion of the coupling for two cases of Hurricane Opal (1995) and one case of Hurricane Gilbert (1988) in the Gulf of Mexico and two cases each of Hurricanes Felix (1995) and Fran (1996) in the western Atlantic. The results confirmed the conclusions suggested by the earlier idealized studies that the cooling of the sea surface induced by the tropical cyclone will have a significant impact on the intensity of observed storms, particularly for slow moving storms where the SST decrease is greater. In each of the seven forecasts, the ocean coupling led to substantial improvements in the prediction of storm intensity measured by the storm’s minimum sea level pressure. Without the effect of coupling the GFDL model incorrectly forecasted 25-hPa deepening of Gilbert as it moved across the Gulf of Mexico. With the coupling included, the model storm deepened only 10 hPa, which was much closer to the observed amount of 4 hPa. Similarly, during the period that Opal moved very slowly in the southern Gulf of Mexico, the coupled model produced a large SST decrease northwest of the Yucatan and slow deepening consistent with the observations. The uncoupled model using the initial NCEP SSTs predicted rapid deepening of 58 hPa during the same period. Improved intensity prediction was achieved both for Hurricanes Felix and Fran in the western Atlantic. For the case of Hurricane Fran, the coarse resolution of the NCEP SST analysis could not resolve Hurricane Edouard’s wake, which was produced when Edouard moved in nearly an identical path to Fran four days earlier. As a result, the operational GFDL forecast using the operational SSTs and without coupling incorrectly forecasted 40-hPa deepening while Fran remained at nearly constant intensity as it crossed the wake. When the coupled model was run with Edouard’s cold wake generated by imposing hurricane wind forcing during the ocean initialization, the intensity prediction was significantly improved. The model also correctly predicted the rapid deepening that occurred as Fran began to move away from the cold wake. These results suggest the importance of an accurate initial SST analysis as well as the inclusion of the ocean coupling, for accurate hurricane intensity prediction with a dynamical model. Recently, the GFDL hurricane‐ocean coupled model used in these case studies was run on 163 forecasts during the 1995‐98 seasons. Improved intensity forecasts were again achieved with the mean absolute error in the forecast of central pressure reduced by about 26% compared to the operational GFDL model. During the 1998 season, when the system was run in near‐real time, the coupled model improved the intensity forecasts for all storms with central pressure higher than 940 hPa although the most significant improvement (;60%) occurred in the intensity range of 960‐970 hPa. These much larger sample sets confirmed the conclusion from the case studies, that the hurricane‐ocean interaction is an important physical mechanism in the intensity of observed tropical cyclones.

Validation of Bupropion Hydroxylation as a Selective Marker of Human Cytochrome P450 2B6 Catalytic Activity

Abstract: The purpose of this study was to establish bupropion (BUP) hydroxylation as a selective in vitro marker of cytochrome P450 (CYP) 2B6 catalytic activity. Among a panel of 16 human liver microsomes (HLMs), BUP hydroxylase activity varied 80-fold when assayed at 500 microM substrate and significantly correlated with CYP2B6 blotting density (r(2) = 0.99) and S-mephenytoin N-demethylase activity (r(2) = 0.98). Kinetic analysis of BUP hydroxylation was performed in a subset of seven HLMs representative of the 80-fold range in activity. Sigmoidal kinetics suggestive of allosteric activation was observed in five HLMs exhibiting low or high activity; the mean apparent K(m) for BUP hydroxylation in these HLMs (130 microM) was similar to the K(m) for cDNA-expressed CYP2B6 (156 microM). Nonsaturable, biphasic kinetics was observed in two HLMs exhibiting low activity. Among a panel of cDNA-expressed P450 isoforms, CYP2B6 and CYP2E1 demonstrated the highest rates of BUP hydroxylation at 12 mM BUP (7.0 and 2.4 pmol/min/pmol of P450, respectively). The relative contributions of CYP2B6 and CYP2E1 to BUP hydroxylation were estimated by using immunoinhibitory monoclonal antibodies (MAB) to these enzymes. MAB-2B6 produced 88% maximum inhibition of BUP hydroxylation when assayed at 12 mM BUP in a high activity HLM, whereas MAB-2E1 produced 81% maximum inhibition in a low activity HLM. However, negligible inhibition by MAB-2E1 was observed when low and high activity HLMs were assayed at 500 microM BUP. These results demonstrate selectivity of BUP hydroxylation for CYP2B6 at 500 microM BUP, thereby validating its use as a diagnostic in vitro marker of CYP2B6 catalytic activity.

Are multispecies models an improvement on single-species models for measuring fishing impacts on marine ecosystems?

Abstract: We review the application of multispecies models as tools for evaluating impacts of fishing on marine communities. Four types of model are identified: descriptive multispecies, dynamic multispecies, aggregate system, and dynamic system models. The strengths and weaknesses of multispecies models and their ability to evaluate the causal mechanisms underlying shifts in production are examined. This comparison provides a basis for assessing the benefits of each modelling approach as a tool for evaluating impacts of fishing in marine ecosystems. Benefits of multispecies models include: improved estimates of natural mortality and recruitment; better understanding of spawner–recruit relationships and of variability in growth rates; alternative views on biological reference points; and a framework for evaluating ecosystem properties. Populations are regulated by competition (food limitation), predation, and environmental variability. Each factor may influence different life-history stages, locally or regionally. However, most multispecies models address only a subset of these factors, often aggregated over functionally different species or age groups. Models that incorporate the important interactions at specific stages and scales will be necessary if they are to continue to supplement the information provided by single-species models. 2000 International Council for the Exploration of the Sea

The Heroic Client: A Revolutionary Way to Improve Effectiveness Through Client-Directed, Outcome-Informed Therapy

Abstract: Foreword to the Revised Edition (Bruce E. Wampold).Foreword to the First Edition (Larry E. Beutler).Preface.1. Therapy at the Crossroads.2. The Myth of the Medical Model.3. Becoming Client Directed.4. Becoming Outcome Informed with Lynn Johnson, Jeb Brown, and Morten Anker.5 The Client's Theory of Change with Susanne Coleman, Lisa Kelledy, and Steven Kopp.6 The Myth of the Magic Pill with Grace Jackson, Roger P. Greenberg, and Karen Kinchin.7 Planet Mental Health.Epilogue: A Tale of Two Therapies.Appendixes.I. A First-Person Account of Mental Health Services (Ronald Bassman).II. Consumer/Survivor/Ex-Patient Resource Information (Ronald Bassman).III. Five Questions About Psychotherapy.IV. Outcome Rating Scale and Session Rating Scale Experimental Versions for Children.References.About the Authors.Name Index.Subject Index.

Distribution and fate of selected oxygenated organic species in the troposphere and lower stratosphere over the Atlantic

Abstract: A large number of oxygenated organic chemicals (peroxyacyl nitrates, alkyl nitrates, acetone, formaldehyde, methanol, methylhydroperoxide, acetic acid and formic acid) were measured during the 1997 Subsonic Assessment (SASS) Ozone and Nitrogen Oxide Experiment (SONEX) airborne field campaign over the Atlantic. In this paper, we present a first picture of the distribution of these oxygenated organic chemicals (Ox-organic) in the troposphere and the lower stratosphere, and assess their source and sink relationships. In both the troposphere and the lower stratosphere, the total atmospheric abundance of these oxygenated species (ΣOx-organic) nearly equals that of total nonmethane hydrocarbons (ΣNMHC), which have been traditionally measured. A sizable fraction of the reactive nitrogen (10–30%) is present in its oxygenated organic form. The organic reactive nitrogen fraction is dominated by peroxyacetyl nitrate (PAN), with alkyl nitrates and peroxypropionyl nitrate (PPN) accounting for <5% of total NOy. Comparison of observations with the predictions of the Harvard three-dimensional global model suggests that in many key areas (e.g., formaldehyde and peroxides) substantial differences between measurements and theory are present and must be resolved. In the case of CH3OH, there appears to be a large mismatch between atmospheric concentrations and estimated sources, indicating the presence of major unknown removal processes. Instrument intercomparisons as well as disagreements between observations and model predictions are used to identify needed improvements in key areas. The atmospheric chemistry and sources of this group of chemicals is poorly understood even though their fate is intricately linked with upper tropospheric NOx and HOx cycles.

Contraindicated use of cisapride: impact of food and drug administration regulatory action.

Abstract: ContextCisapride, a gastrointestinal tract promotility agent, can cause life-threatening cardiac arrhythmias in patients susceptible either because of concurrent use of medications that interfere with cisapride metabolism or prolong the QT interval or because of the presence of other diseases that predispose to such arrhythmias. In June 1998, the US Food and Drug Administration (FDA) determined that use of cisapride was contraindicated in such patients and informed practitioners through additions to the boxed warning in the label and a "Dear Health Care Professional" letter sent by the drug's manufacturer.ObjectiveTo evaluate the impact of the FDA's 1998 regulatory action regarding contraindicated use of cisapride.Design and SettingAnalysis of data for the 1-year periods before (July 1997-June 1998) and after (July 1998-June 1999) the regulatory action from the population-based, pharmacoepidemiology research databases of 2 managed care organizations (sites A and B) and a state Medicaid program (site C).ParticipantsPatients with at least 180 days of prior enrollment in 1 of the 3 sites who were prescribed cisapride at least once in the period before (n = 24 840) or after (n = 22 459) regulatory action. Patients could be included in both cohorts.Main Outcome MeasuresProportion of cisapride users in each period for whom cisapride use was contraindicated by the product label, based on computerized patient medical encounter records.ResultsIn the year prior to regulatory action, cisapride use was contraindicated for 26%, 30%, and 60% of users in study sites A, B, and C, respectively. In the year after regulatory action, use was contraindicated for 24%, 28%, and 58% of users, a reduction in contraindicated use of approximately 2 per 100 cisapride users at each site. When the analysis was restricted to new users of cisapride after regulatory action, only minor reductions in contraindicated use were found.ConclusionThe FDA's 1998 regulatory action regarding cisapride use had no material effect on contraindicated cisapride use. More effective ways to communicate new information about drug safety are needed.

Spatial patterns in abundance of a damselfish reflect availability of suitable habitat.

Abstract: For species with metapopulation structures, variation in abundance among patches can arise from variation in the input rate of colonists. For reef fishes, variability in larval supply frequently is invoked as a major determinant of spatial patterns. We examined the extent to which spatial variation in the amount of suitable habitat predicted variation in the abundance of the damselfish Dascyllus aruanus, an abundant planktivore that occupies live, branched coral throughout the Indo-Pacific. Reef surveys established that size, branching structure and location (proximity to sand) of the coral colonies together determined the "suitability" of microhabitats for different ontogenetic stages of D. aruanus. Once these criteria were known, patterns of habitat use were quantified within lagoons of five Pacific islands. Availability of suitable habitat generally was an excellent predictor of density, and patterns were qualitatively consistent at several spatial scales, including among different lagoons on the same island, among different islands and between the central (French Polynesia and Rarotonga) and western (Great Barrier Reef, Australia) South Pacific. A field experiment that varied the amount of suitable coral among local plots indicated that habitat for settlers accounted for almost all of the spatial variation in the number of D. aruanus that settled at that location, suggesting that spatial patterns of abundance can be established at settlement without spatial variation in larval supply. Surveys of four other species of reef-associated fish revealed that a substantial fraction of their spatial variation in density also was explained by availability of suitable reef habitat, suggesting that habitat may be a prevalent determinant of spatial patterns. The results underscore the critical need to identify accurately the resource requirements of different species and life stages when evaluating causes of spatial variation in abundance of reef fishes.

Microbial food web structure in the Arabian Sea: a US JGOFS study

Abstract: One of the main objectives of the Joint Global Ocean Flux Studies (JGOFS) program is to develop an understanding of the factors controlling organic carbon production in the ocean and the time-varying vertical #ux of carbon from surface waters (US JGOFS (1990) US JGOFS Planning Report Number 11; Sarmiento and Armstrong (1997) US JGOFS Synthesis and Modeling Project Implementation Plan). A considerable amount of evidence suggests that carbon cycling and the potential for exporting carbon from ocean systems is a function of food web structure. As part of the US JGOFS Arabian Sea Studies, the biomass of planktonic organisms, ranging from heterotrophic bacteria through microplankton-sized organisms, was estimated using a variety of methods including #ow cytometry and microscopy. This is a "rst attempt to combine biomass data from a number of sources, evaluate the structure of the food

Gender Differences in Student Attitudes toward Computers.

Abstract: This study reports the development of a student computer attitude survey The instrument highlighted gender differences in computer attitudes of 462 middle and high school students The principal components analysis confirmed five expected factors: confidence, perception of computers as male domain, positive teacher attitudes, negative teacher attitudes, and perceived usefulness of computers The main gender differences related to greater confidence among males and the perception of computers as a male domain supported by males and rejected by females Male students reported high levels of negative interactions with teachers, though this did not affect their confidence or skill level

Can detectability be improved by adding noise

Abstract: It is shown that under certain conditions the performance of a suboptimal detector may be improved by adding noise to the received data. The reasons for this counterintuitive result are explained and a computer simulation example given.

Citizen Participation and Community Organizations

Abstract: The noted black educator Benjamin Mays said: “nobody is wise enough, nobody is good enough, and nobody cares enough about you, for you to turn over to them your future or your destiny.” Citizen participation creates the potential for schools, neighborhoods, and other institutions, environments, and services responsive to individuals and families. Citizen participation is defined as “a process in which individuals take part in decision making in the institutions, programs, and environments that affect them” (Heller, Price, Reinharz, Riger, & Wandersman, 1984, p. 339; see Churchman, 1987, for definitions of participation in different disciplines)

Development and Validation of a Stages of Change Measure for Men in Batterer Treatment

Abstract: The Transtheoretical Model of Change offers a promising stage-based approach to client–treatment matching to increase the efficacy of batterer treatment. This paper describes the development and validation of the URICA–Domestic Violence (URICA-DV), a four-dimensional stage measure assessing batterers' readiness to end their violence. Two hundred fifty-eight batterers in treatment at two Rhode Island agencies completed a questionnaire that included the URICA-DV, demographics, and measures expected to vary systematically with stage in a manner predicted by the Transtheoretical Model. A cross-validated cluster analysis yielded seven stage clusters based on URICA-DV scores: Reluctant, Immotive, Nonreflective Action, Unprepared Action, Preparticipation, Decision-making, and Participation. Findings provide preliminary evidence of validity of the URICA-DV. For example, participants in the most advanced stage clusters were most likely to have used strategies to end the violence in the last year. They engaged in less partner blame and valued the Pros and minimized the Cons of changing more than counterparts in the earlier stage clusters. Longitudinal research to assess the predictive validity of the URICA-DV is necessary.

Photochemistry of HOx in the upper troposphere at northern midlatitudes

Abstract: The factors controlling the concentrations of HOx radicals (= OH + peroxy) in the upper troposphere (8–12 km) are examined using concurrent aircraft observations of OH, HO2, H2O2, CH3OOH, and CH2O made during the Subsonic Assessment Ozone and Nitrogen Oxide Experiment (SONEX) at northern midlatitudes in the fall. These observations, complemented by concurrent measurements of O3, H2O, NO, peroxyacetyl nitrate (PAN), HNO3, CH4, CO, acetone, hydrocarbons, actinic fluxes, and aerosols, allow a highly constrained mass balance analysis of HOx and of the larger chemical family HOy (= HOx + 2 H2O2 + 2 CH3OOH + HNO2 + HNO4). Observations of OH and HO2 are successfully simulated to within 40% by a diel steady state model constrained with observed H2O2 and CH3OOH. The model captures 85% of the observed HOx variance, which is driven mainly by the concentrations of NOx (= NO + NO2) and by the strength of the HOx primary sources. Exceptions to the good agreement between modeled and observed HOx are at sunrise and sunset, where the model is too low by factors of 2–5, and inside cirrus clouds, where the model is too high by factors of 1.2–2. Heterogeneous conversion of NO2 to HONO on aerosols (γNO2 = 10−3) during the night followed by photolysis of HONO could explain part of the discrepancy at sunrise. Heterogeneous loss of HO2 on ice crystals (γice_HO2 = 0.025) could explain the discrepancy in cirrus. Primary sources of HOx from O(1D)+H2O and acetone photolysis were of comparable magnitude during SONEX. The dominant sinks of HOy were OH+HO2 (NOx 50 pptv). Observed H2O2 concentrations are reproduced by model calculations to within 50% if one allows in the model for heterogeneous conversion of HO2 to H2O2 on aerosols (γHO2 = 0.2). Observed CH3OOH concentrations are underestimated by a factor of 2 on average. Observed CH2O concentrations were usually below the 50 pptv detection limit, consistent with model results; however, frequent occurrences of high values in the observations (up to 350 pptv) are not captured by the model. These high values are correlated with high CH3OH and with cirrus clouds. Heterogeneous oxidation of CH3OH to CH2O on aerosols or ice crystals might provide an explanation (γice_CH3OH ∼ 0.01 would be needed).

On the recursive sequence

Abstract: We investigate the global stability, and the periodicity of the recursive sequence where the parameters α,β and A and the initial condition x-1 and Xo are non negative real numbers.

Phase changes in 38 atom Lennard-Jones clusters. II: A parallel tempering study of equilibrium and dynamic properties in the molecular dynamics and microcanonical

Abstract: We study the 38-atom Lennard-Jones cluster with parallel tempering Monte Carlo methods in the microcanonical and molecular dynamics ensembles. A new Monte Carlo algorithm is presented that samples rigorously the molecular dynamics ensemble for a system at constant total energy, linear and angular momenta. By combining the parallel tempering technique with molecular dynamics methods, we develop a hybrid method to overcome quasi-ergodicity and to extract both equilibrium and dynamical properties from Monte Carlo and molecular dynamics simulations. Several thermodynamic, structural and dynamical properties are investigated for LJ$_{38}$, including the caloric curve, the diffusion constant and the largest Lyapunov exponent. The importance of insuring ergodicity in molecular dynamics simulations is illustrated by comparing the results of ergodic simulations with earlier molecular dynamics simulations.

Early onset and tropical forcing of 100,000-year Pleistocene glacial cycles

Abstract: Between 1.5 and 0.6 Myr ago, the period of the Earth's glacial cycles changed from 41 kyr, the period of the Earth's obliquity cycles, to 100 kyr, the period of the Earth's orbital eccentricity, which has a much smaller effect on global insolation. The timing of this transition and its causes pose one of the most perplexing problems in palaeoclimate research. Here we use complex demodulation to examine the phase evolution of precession and semiprecession cycles--the latter of which are phase-coupled to both precession and eccentricity--in the tropical and extratropical Atlantic Ocean. We find that about 1.5 Myr ago, tropical semiprecession cycles (with periods of about 11.5 kyr) started to propagate to higher latitudes, coincident with a growing amplitude envelope of the 100-kyr cycles. Evidence from numerical models suggests that cycles of about 10 kyr in length may be required to explain the high amplitude of the 100-kyr cycles. Combining our results with consideration of a modern analogue, we conclude that increased heat flow across the equator or from the tropics to higher latitudes around 1.5 Myr ago strengthened the semiprecession cycle in the Northern Hemisphere, and triggered the transition to sustained 100-kyr glacial cycles.

Climatology and seasonal variability of ocean fronts in the East China, Yellow and Bohai seas from satellite SST data

Abstract: Front detection and declouding algorithms developed at the URI have been applied to the 12-year (1985–1996) Pathfinder SST data set to produce the first comprehensive, objectively derived, year-round climatology of ocean thermal fronts in the eastern China Seas, from 24°N to 41°N. Ten fronts have been distinguished, namely Kuroshio, Zhejiang-Fujian, Jiangsu, Shandong Peninsula, Bohai Sea, Seohan Bay, Kyunggi Bay, Western and Eastern Chejudo (South Korean Coastal Front), and Yangtze Bank Ring Front. The fronts are seasonally persistent: they emerge and disappear in the same seasons of different years. The frontal pattern remains fairly stable from one year to another, whereas individual fronts display different modes of seasonal variability.

Measurement of photographic quality and individual distinctiveness for the photographic identification of humpback whales, megaptera novaeangliae

Abstract: Accurate identification of humpback whales from photographic identification data depends on the quality of the photographs and the distinctiveness of the flukes. Criteria for evaluating photographic quality and individual distinctiveness were developed involving judgments about overall quality or distinctiveness and about specific aspects of each. These criteria were tested for the level of agreement among judges. The distinctiveness scheme was tested for the independence of distinctiveness judgments and photographic quality. Our results show that judges could agree when evaluating specific and overall aspects of photographic quality and individual distinctiveness. The level of agreement varied for different pairs of judges, and less adept judges were identified. Ability to agree on evaluations of photographic quality was independent of the experience of the judges. Overall photographic quality and overall distinctiveness were successfully predicted from more specific variables, but the agreement between judges for these was not significantly greater than the agreement for the overall measures judged directly. There was no correlation between individual distinctiveness and photographic quality for four of the five judges, but the power of this rest may be low. Analyses of photographic identification data frequently require evaluations of photographic quality and individual distinctiveness. To obtain reliable results from such analyses, evaluation schemes and judges should be tested to ensure reliable and consistent evaluations.