Showing papers by "University of Rhode Island published in 1998"

Chondrogenic Differentiation of Cultured Human Mesenchymal Stem Cells from Marrow

Abstract: In the adult human, mesenchymal stem cells (MSCs) resident in bone marrow retain the capacity to proliferate and differentiate along multiple connective tissue lineages, including cartilage. In this study, culture-expanded human MSCs (hMSCs) of 60 human donors were induced to express the morphology and gene products of chondrocytes. Chondrogenesis was induced by culturing hMSCs in micromass pellets in the presence of a defined medium that included 100 nM dexamethasone and 10 ng/ml transforming growth factor-beta(3) (TGF-beta(3)). Within 14 days, cells secreted an extracellular matrix incorporating type II collagen, aggrecan, and anionic proteoglycans. hMSCs could be further differentiated to the hypertrophic state by the addition of 50 nM thyroxine, the withdrawal of TGF-beta(3), and the reduction of dexamethasone concentration to 1 nM. Increased understanding of the induction of chondrogenic differentiation should lead to further progress in defining the mechanisms responsible for the generation of cartilaginous tissues, their maintenance, and their regeneration.

Timing of abrupt climate change at the end of the Younger Dryas interval from thermally fractionated gases in polar ice

Abstract: Rapid temperature change fractionates gas isotopes in unconsolidated snow, producing a signal that is preserved in trapped air bubbles as the snow forms ice The fractionation of nitrogen and argon isotopes at the end of the Younger Dryas cold interval, recorded in Greenland ice, demonstrates that warming at this time was abrupt This warming coincides with the onset of a prominent rise in atmospheric methane concentration, indicating that the climate change was synchronous (within a few decades) over a region of at least hemispheric extent, and providing constraints on previously proposed mechanisms of climate change at this time The depth of the nitrogen-isotope signal relative to the depth of the climate change recorded in the ice matrix indicates that, during the Younger Dryas, the summit of Greenland was 15 ± 3 °C colder than today

Identifying Marine Phytoplankton

Abstract: Until recently, anyone who needed to accurately identify marine phytoplankton had one of four choices: use the outdated Englishlanguage volumes by E. E. Cupp and N. I. Hendey plus the more recent book by J. Dodge, acquire a working knowledge of German and use the old volumes by Schiller and Hustedt, spend huge amounts of time in an exceedingly well-equipped marine science library trying in vain to keep up with the rapidly evolving field of phytoplankton systematics and taxonomy, or track down one of the rarest of endangered species—a phytoplankton taxonomist—and beg for help. To these unfortunate choices is added one considerably more hopeful: Identifying Marine Phytoplankton. This volume, which has seven contributing authors, contains most of the taxonomic groups that make up the planktonic autotrophs and some heterotrophs of the seas, coasts, and estuaries of the world (missing are cyanobacteria and some of the picoplankton groups).

Nested PCR Assay for Detection of Granulocytic Ehrlichiae

Abstract: A sensitive and specific nested PCR assay was developed for the detection of granulocytic ehrlichiae. The assay amplifies the 16S rRNA gene and was used to examine acute-phase EDTA-blood and serum samples obtained from seven humans with clinical presentations compatible with human granulocytic ehrlichiosis. Five of the seven suspected cases were positive by the PCR assay using DNA extracted from whole blood as the template, compared with a serologic assay that identified only one positive sample. The PCR assay using DNA extracted from the corresponding serum samples as the template identified three positive samples. The sensitivity of the assay on human samples was examined, and the limit of detection was shown to be fewer than 2 copies of the 16S rRNA gene. The application of the assay to nonhuman samples demonstrated products amplified from template DNA extracted from Ixodes scapularis ticks collected in Rhode Island and from EDTA-blood specimens obtained from white-tailed deer in Maryland. All PCR products were sequenced and identified as specific to granulocytic ehrlichiae. A putative variant granulocytic ehrlichia 16S rRNA gene sequence was detected among products amplified from both the ticks and the deer blood specimens.

An introduction to the chemistry of the sea

Abstract: Fully updated and expanded, this new edition provides students with an accessible introduction to marine chemistry. It highlights geochemical interactions between the ocean, solid earth, atmosphere and climate, enabling students to appreciate the interconnectedness of Earth's processes and systems and elucidates the huge variations in the oceans' chemical environment, from surface waters to deep water. Written in a clear, engaging way, the book provides students in oceanography, marine chemistry and biogeochemistry with the fundamental tools they need for a strong understanding of ocean chemistry. Appendices present information on seawater properties, key equations and constants for calculating oceanographic processes. New to this edition are end-of-chapter problems for students to put theory into practice, summaries to allow easy review of material and a comprehensive glossary. Supporting online resources include solutions to problems and figures from the book.

Blue Water Crime: Deterrence, Legitimacy, and Compliance in Fisheries

Abstract: This study adds to the limited body of empirical evidence on the effect that legitimacy and deterrence have on compliance behavior. The theoretical models of compliance behavior tested include the basic deterrence model, which focuses on the certainty and severity of sanctions as key determinants of compliance, and models which integrate economic theory with theories from social psychology to account for legitimacy, deterrence, and other motivations expected to influence indiv duals' decisions whether to comply. Probit and Tobit econometric estimators are used to examine the compliance behavior of 318 Peninsular Malaysian fishermen who face a regulation banning them from fishing in a zone along the coast. The results of the empirical analysis provide additional evidence on the relationship of deterrence and legitimacy to compliance. The findings are also used to draw implications for compliance policy for regulated fisheries. According to normative compliance theory, people tend to obey laws made and implemented by authorities perceived to be legitimate. A key determinant of perceived legitimacy, according to the procedural justice literature, is the fairness built into the procedures used to develop and implement laws and regulations.l Paternoster et al. (1997) note that while there are numerous theoretical perspectives suggesting that legitimacy is an important determinant of compliance, the empirical evidence making that connection is meager.2 Our study adds to this limited body of empirical evidence. The subjects of our study are fishermen. Fishermen are excellent subjects for the study of compliance. They are subject to numerous regulations that constrain their opportunities to earn income, and temptations and opportunities for offending repeatedly occur.3 Passion, inadvertence, and accident rarely cause a fishery violation; most are the result of deliberate choice. The behavior of fishermen offers good evidence on which to test the role deterrence, legitimacy, and other factors play in explaining compliance. Studying the compliance behavior of such regulated economic agents as fishermen is important for other reasons. Achieving compliance in regulated industries is both costly and difficult. Expenditures on enforcement commonly constitute the largest cost element in governmental regulatory programs. The viability of environmental protection and resource management programs is often threatened by low rates of compliance and high enforcement costs. This raises questions whether there are ways to improve the cost effectiveness of traditional enforcement and whether there are ways to secure compliance without heavy reliance on costly enforcement. Central to improving the cost effectiveness of enforcement and compliance programs is understanding the compliance behavior of the economic agents subject to regulations. To this end, we present tests of alternative models of compliance behavior. The models tested include the basic deterrence model, which focuses on the certainty and severity of sanctions as key determinants of compliance, and models which integrate economic theory with theories from social psychology to account for both intrinsic and extrinsic motivations influencing individuals' decisions whether to comply.4 The tests are conducted on data from interviews with fishermen in Peninsular Malaysia (selfreports of violations). Becker (1968) was the first to develop a formal theoretical framework for explaining criminal activity. Following Smith (1966 [1759], 1985 [1776]) and Bentham (1967 [1789]), Becker assumes that criminals behave basically like other individuals in that they attempt to maximize utility subject to a budget constraint. In Becker's model, an individual commits a crime if the expected utility from committing the crime exceeds the utility from engaging in legitimate activity.5 The basic deterrence framework used in these studies assumes that the threat of sanctions is the only policy mechanism available to improve compliance with regulations. …

Evaluation of motivationally tailored vs. standard self-help physical activity interventions at the workplace.

Abstract: Purpose. This study compares the efficacy of a self-help intervention tailored to the individual's stage of motivational readiness for exercise adoption with a standard self-help exercise promotion intervention. Design. Interventions were delivered at baseline and 1 month; assessments were collected at baseline and 3 months. Setting. Eleven worksites participating in the Working Healthy Research Trial. Subjects. Participants (n = 1559) were a subsample of employees at participating worksites, individually randomized to one of two treatment conditions. Intervention. Printed self-help exercise promotion materials either (1) matched to the individual's stage of motivational readiness for exercise adoption (motivationally tailored), or (2) standard materials (standard). Measures. Measures of stage of motivational readiness for exercise and items from the 7-Day Physical Activity Recall. Results. Among intervention completers (n = 903), chi-square analyses showed that, compared to the standard intervention, tho...

The influence of geomorphological heterogeneity on biodiversity. I. A patch-scale perspective.

Abstract: Landscapes composed of spatially heterogeneous abiotic conditions should provide a greater diver- sity of potential niches for plants and animals than do homogeneous landscapes. We tested this hypothesis in a deciduous forest ecosystem in the northeastern United States. We created an index that summarizes the col- lective variation in terrain and soil properties in 2-ha study plots. We measured woody plant species richness and diversity in 20 study plots that had high geomorphological heterogeneity and 20 plots that had low geo- morphological heterogeneity. The richness and diversity of trees and shrubs were significantly higher in sites with high geomorphological heterogeneity than in sites that exhibited little change in terrain or soil condi- tions. Variation in aspect and soil drainage were especially important predictors of biotic diversity. Our re- sults demonstrate an intimate association between abiotic and biotic diversity and have significant implica- tions for long-term conservation strategies.

Consumer Decision‐Making Styles of Young‐Adult Chinese

Abstract: The dimensions and profiles of consumer decision-making styles of young-adult Chinese are investigated using a modified model of consumer decision-making styles and data recently collected from five Chinese universities. The results are then compared with those of similar studies using American and Korean data. While the dimensions of consumer decision-making styles are similar in these three countries, differences in consumer purchasing power and, maturity of the consumer market may contribute to the differences in consumer decision-making styles.

Origin of upper-ocean warming and El Niño change on decadal scales in the tropical Pacific Ocean

Abstract: The cause of decadal-scale variability in the tropical Pacific Ocean—such as that marked by the 1976–77 shift in the El Nino/Southern Oscillation1,2,3,4,5,6,7—is poorly understood. Unravelling the mechanism of the recent decade-long warming in the tropical upper ocean is a particularly important challenge, given the link to El Nino variability, but establishing the hypothesized interannual/decadal oceanic connections between middle latitudes and tropics has proved elusive8. Here we present observational evidence that Pacific upper-ocean warming and decadal changes in the El Nino/Southern Oscillation after 1976 may originate from decadal mid-latitude variability. In the middle 1970s the North Pacific Ocean is observed to have undergone a clear phase-transition; a ‘see-saw’ subsurface temperature anomaly pattern that rotates clockwise around the subtropical gyre. At middle latitudes a subsurface warm anomaly formed in the early 1970s from subducted surface-waters and penetrated through the subtropics and into the tropics, thus perturbing the tropical thermocline and driving the formation of a warm surface-water anomaly that may have influenced El Nino in the 1980s. The identification of this teleconnection of extratropical thermal anomalies to the tropics, through a subsurface ocean ‘bridge’, may enable improved prediction of decadal-scale climate variability.

Controlled drug delivery by biodegradable poly (ester) devices: different preparative approaches

Abstract: There has been extensive research on drug delivery by biodegradable polymeric devices since bioresorbable surgical sutures entered the market two decades ago. Among the different classes of biodegradable polymers, the thermoplastic aliphatic poly (esters) such as poly(lactide) (PLA), poly(glycolide) (PGA), and especially the copolymer oflactide and glycolide referred to as poly(lactide-co-glycolide) (PLGA) have generated tremendous interest because of their excellent biocompatibility, biodegradability, and mechanical strength. They are easy to formulate into various devices for carrying a variety of drug classes such as vaccines, peptides, proteins, and micromolecules. Most importantly, they have been approved by the United States Food and Drug Administration (FDA) for drug delivery. This review presents different preparation techniques of various drug-loaded PLGA devices, with special emphasis on preparing microparticles. Certain issues about other related biodegradable polyesters are discussed.

Photochemistry in biomass burning plumes and implications for tropospheric ozone over the tropical South Atlantic

Abstract: Photochemistry occuring in biomass burning plumes over the tropical south Atlantic is analyzed using data collected during the Transport and Atmospheric Chemistry Near the Equator-Atlantic aircraft expedition conducted during the tropical dry season in September 1992 and a photochemical point model. Enhancement ratios (ΔY/ΔX, where Δ indicates the enhancement of a compound in the plume above the local background mixing ratio, Y are individual hydrocarbons, CO, O3, N2O, HNO3, peroxyacetyl nitrate (PAN), CH2O, acetone, H2O2, CH3OOH, HCOOH, CH3COOH or aerosols and X is CO or CO2) are reported as a function of plume age inferred from the progression of Δnon-methane hydrocarbons/ΔCO enhancement ratios. Emission, formation, and loss of species in plumes can be diagnosed from progression of enhancement ratios from fresh to old plumes. O3 is produced in plumes over at least a 1 week period with mean ΔO3/ΔCO = 0.7 in old plumes. However, enhancement ratios in plumes can be influenced by changing background mixing ratios and by photochemical loss of CO. We estimate a downward correction of ∼20% in enhancement ratios in old plumes relative to ΔCO to correct for CO loss. In a case study of a large persistent biomass burning plume at 4-km we found elevated concentrations of PAN in the fresh plume. The degradation of PAN helped maintain NOx mixing ratios in the plume where, over the course of a week, PAN was converted to HNO3. Ozone production in the plume was limited by the availability of NOx, and because of the short lifetime of O3 at 4-km, net ozone production in the plume was negligible. Within the region, the majority of O3 production takes place in air above median CO concentration, indicating that most O3 production occurs in plumes. Scaling up from the mean observed ΔO3/ΔCO in old plumes, we estimate a minimum regional O3 production of 17×1010molecules O3 cm−2 s−1. This O3 production rate is sufficient to fully explain the observed enhancement in tropospheric O3 over the tropical South Atlantic during the dry season.

Motivation Sources Inventory: Development and Validation of New Scales to Measure an Integrative Taxonomy of Motivation

Abstract: Scales are developed and tested based on an integrative taxonomy of motivation sources. The sources, as measured on the Motivation Sources Inventory include intrinsic process, instrumental, externa...

Marketing images of gender: A visual analysis

Abstract: An interpretive method drawing from social psychology, feminist theory and art criticism is developed to analyze contemporary images of gender. Utilizing and expanding upon visual research techniques, a selection of ads from contemporary fashion magazines and catalogs was assembled to illustrate particular themes suggested by research on the representation of gender in advertising. The body‐and what it expresses‐is a site of central concern, and discussion focuses on how female and male bodies are represented in advertising. The conventions of art history, when framed within a social science perspective, offer unique contributions to the study of advertising and gender, well suited for researchers interested in the culture of consumption.

Physical self-concept : assessment and external validity

Abstract: This chapter summarized knowledge about the physical SC, a variable that has assumed great importance in studying how self-esteem is related to physical activity participation. It discussed the advantages of employing component scales such as physical SCs, and reviewed research and theory on the development of the physical SC, age and sex differences, and relationships with life adjustment. Skill development and self-enhancement research were summarized. Leading physical SC scales were briefly reviewed. A thesis of the chapter is that SE and its associations with physical activity participation can be studied best by the employment of models that are hierarchical in their structure, and which contain SC components ranging from very specific to very broad constructs. This has implications for item and inventory selection and for an ultimate understanding of how physical activity leads to mental and emotional benefits.

Evaluating relationships: are satisfaction and quality enough?

Abstract: This paper examines the current literature and trends in the measurement of service relationships. The authors present evidence from two industry studies which suggests that satisfaction and/or quality as currently conceptualized are not sufficient diagnostic tools to assess the health of a relationship, certainly not sufficient when only one relationship partner’s outcomes are assessed. Two studies which explore service relationship satisfaction, are presented as illustrations to demonstrate that firms engaged in partnering relationships need to consider changing the way they evaluate the ability of their systems to satisfy partners as the relationship progresses. Process issues and value‐enhancing components in addition to satisfaction and quality are among the critical dimensions to evaluate in order to fully assess the health of a relationship.

Occurrence of male-specific bacteriophage in feral and domestic animal wastes, human feces, and human-associated wastewaters.

Abstract: Male-specific bacteriophage (MSB) densities were determined in animal and human fecal wastes to assess their potential impact on aquatic environments. Fecal samples (1,031) from cattle, chickens, dairy cows, dogs, ducks, geese, goats, hogs, horses, seagulls, sheep, and humans as well as 64 sewerage samples were examined for MSB. All animal species were found to harbor MSB, although the great majority excreted these viruses at very low levels. The results from this study demonstrate that in areas affected by both human and animal wastes, wastewater treatment plants are the principal contributors of MSB to fresh, estuarine, and marine waters.

A structural model of the relationships among stage of disease, age, coping, and psychological adjustment in women with breast cancer

Abstract: The present study used structural equation modeling to examine the relationships among disease stage (i.e. Stage II versus Stage IV), age, coping style, and psychological adjustment in 100 women diagnosed with breast cancer. Five separate models were examined: a full model, a mediational model, a demographic-disease model, a coping style model, and a regression model The analyses revealed that the present data best fit the mediational model in which age and stage of disease were not directly associated with psychological adjustment but, instead, were mediated by coping style (chi 2(25) = 45.776, AASR = 0.05, CFI = 0.94). The mediational model accounted for 56% of the variance in psychological adjustment. In particular, the model showed that younger women and women with an earlier disease stage used greater levels of the coping strategy characterized as a fighting spirit and lower levels of the coping strategies characterized as hopelessness/helplessness, anxious preoccupation, and fatalism which, in turn, were related to better psychological adjustment. Overall, these findings may offer an explanation for the conflicting findings regarding the relationship between age, stage of disease, and psychological adjustment to breast cancer by illustrating that coping strategies may be an essential mediating factor; in turn, a mediating model of psychological adaptation may offer useful information for clinicians as they implement interventions designed to improve patients coping efforts.

The annual cycle of SST in the Eastern Tropical Pacific, diagnosed in an ocean GCM

Abstract: The annual onset of the east Pacific cold tongue is diagnosed in an ocean GCM simulation of the tropical Pacific. The model uses a mixed-layer scheme that explicitly simulates the processes of vertical exchange of heat and momentum with the deeper layers of the ocean; comparison with observations of temperature and currents shows that many important aspects of the model fields are realistic. As previous studies have found, the heat balance in the eastern tropical Pacific is notoriously complicated, and virtually every term in the balance plays a significant role at one time or another. However, despite many complications, the three-dimensional ocean advection terms in the cold tongue region tend to cancel each other in the annual cycle and, to first order, the variation of SST can be described as simply following the variation of net solar radiation at the sea surface (sun minus clouds). The cancellation is primarily between cooling due to equatorial upwelling and warming due to tropical instability waves, both of which are strongest in the second half of the year (when the winds are stronger). Even near the equator, where the ocean advection is relatively intense, the terms associated with cloudiness variations are among the largest contributions to the SST balance. The annual cycle of cloudiness transforms the semiannual solar cycle at the top of the atmosphere into a largely 1 cycle yr 21 variation of insolation at the sea surface. However, the annual cycle of cloudiness appears closely tied to SST in coupled feedbacks (positive for low stratus decks and negative for deep cumulus convection), so the annual cycle of SST cannot be fully diagnosed in an ocean-only modeling context as in the present study. Zonal advection was found to be a relatively small influence on annual equatorial cold tongue variations; in particular, there was little direct (oceanic) connection between the Peru coastal upwelling and equatorial annual cycles. Meridional advection driven by cross-equatorial winds has been conjectured as a key factor leading to the onset of the cold tongue. The results suggest that the SST changes due to this mechanism are modest, and if meridional advection is in fact a major influence, then it must be through interaction with another process (such as a coupled feedback with stratus cloudiness). At present, it is not possible to evaluate this feedback quantitatively.