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Showing papers by "University of Rhode Island published in 2001"


Journal ArticleDOI
TL;DR: Close links between psychological control and adjustment were more complex: high levels of psychological control were associated with more delinquent problems for girls and for teens who were low in preadolescent delinquent problems, and with more anxiety/depression forGirls and for girls who were high in preAdolescent anxiety/Depression.
Abstract: The early childhood antecedents and behavior-problem correlates of monitoring and psychological control were examined in this prospective, longitudinal, multi-informant study. Parenting data were collected during home visit interviews with 440 mothers and their 13-year-old children. Behavior problems (anxiety/depression and delinquent behavior) were assessed via mother, teacher, and/or adolescent reports at ages 8 through 10 years and again at ages 13 through 14. Home-interview data collected at age 5 years were used to measure antecedent parenting (harsh/reactive, positive/proactive), family background (e.g., socioeconomic status), and mother-rated child behavior problems. Consistent with expectation, monitoring was anteceded by a proactive parenting style and by advantageous family-ecological characteristics, and psychological control was anteceded by harsh parenting and by mothers' earlier reports of child externalizing problems. Consistent with prior research, monitoring was associated with fewer delinquent behavior problems. Links between psychological control and adjustment were more complex: High levels of psychological control were associated with more delinquent problems for girls and for teens who were low in preadolescent delinquent problems, and with more anxiety/depression for girls and for teens who were high in preadolescent anxiety/depression.

933 citations


Journal ArticleDOI
TL;DR: In this paper, two intense dust storms were generated over the Gobi desert by springtime low-pressure systems descending from the northwest, and the windblown dust was detected and its evolution followed by its yellow color on SeaWiFS satellite images, routine surface-based monitoring and through serendipitous observations.
Abstract: On April 15 and 19, 1998, two intense dust storms were generated over the Gobi desert by springtime low-pressure systems descending from the northwest. The windblown dust was detected and its evolution followed by its yellow color on SeaWiFS satellite images, routine surface-based monitoring, and through serendipitous observations. The April 15 dust cloud was recirculating, and it was removed by a precipitating weather system over east Asia. The April 19 dust cloud crossed the Pacific Ocean in 5 days, subsided to the surface along the mountain ranges between British Columbia and California, and impacted severely the optical and the concentration environments of the region. In east Asia the dust clouds increased the albedo over the cloudless ocean and land by up to 10–20%, but it reduced the near-UV cloud reflectance, causing a yellow coloration of all surfaces. The yellow colored backscattering by the dust eludes a plausible explanation using simple Mie theory with constant refractive index. Over the West Coast the dust layer has increased the spectrally uniform optical depth to about 0.4, reduced the direct solar radiation by 30–40%, doubled the diffuse radiation, and caused a whitish discoloration of the blue sky. On April 29 the average excess surface-level dust aerosol concentration over the valleys of the West Coast was about 20–50 μg/m3 with local peaks >100 μg/m3. The dust mass mean diameter was 2–3 μm, and the dust chemical fingerprints were evident throughout the West Coast and extended to Minnesota. The April 1998 dust event has impacted the surface aerosol concentration 2–4 times more than any other dust event since 1988. The dust events were observed and interpreted by an ad hoc international web-based virtual community. It would be useful to set up a community-supported web-based infrastructure to monitor the global aerosol pattern for such extreme aerosol events, to alert and to inform the interested communities, and to facilitate collaborative analysis for improved air quality and disaster management.

795 citations


Journal ArticleDOI
TL;DR: In this paper, the authors build propositions of price's role vis-a-vis customer value, satisfaction, and behavioral intentions and then test these propositions using empirical data from the banking industry in the United States and New Zealand.
Abstract: Compared to the emphasis that service quality research has received in service marketing, much less work has been done on the role of price perceptions and their effect on customer retention. This article seeks to fill this gap in the literature. The authors build propositions of price’s role vis-a-vis customer value, satisfaction, and behavioral intentions and then test these propositions using empirical data from the banking industry in the United States and New Zealand. Their findings indicate that (a) price perceptions have a stronger influence on customer value perceptions than quality, and (b) price perceptions, when measured on a comparative basis, have a significant direct effect on customer satisfaction and behavioral intentions— over and above their mediated effect through the construct of customer value. These results indicate that price perceptions significantly affect customer retention and suggest that managers may benefit from actively managing consumers’ price perceptions, in addition to c...

515 citations


Journal ArticleDOI

429 citations


Journal ArticleDOI
TL;DR: In this paper, a study was conducted of 45 community-based marine protected areas in Philippines and several success measures were developed and analyzed in relation to a number of independent variables categorized as contextual or project intervention factors.

390 citations


Journal ArticleDOI
26 Apr 2001-Nature
TL;DR: The tropospheric composition of oxygenated organic species is characterized, using data from a recent airborne survey conducted over the tropical Pacific Ocean, and it is suggested that oxygenated species could be formed via the oxidation of hydrocarbons in the atmosphere, the photochemical degradation of organic matter in the oceans, and direct emissions from terrestrial vegetation.
Abstract: The presence of oxygenated organic compounds in the troposphere strongly influences key atmospheric processes. Such oxygenated species are, for example, carriers of reactive nitrogen and are easily photolysed, producing free radicals1,2,3—and so influence the oxidizing capacity and the ozone-forming potential of the atmosphere4,5,6—and may also contribute significantly to the organic component of aerosols7,8. But knowledge of the distribution and sources of oxygenated organic compounds, especially in the Southern Hemisphere, is limited. Here we characterize the tropospheric composition of oxygenated organic species, using data from a recent airborne survey9 conducted over the tropical Pacific Ocean (30° N to 30° S). Measurements of a dozen oxygenated chemicals (carbonyls, alcohols, organic nitrates, organic pernitrates and peroxides), along with several C2–C8 hydrocarbons, reveal that abundances of oxygenated species are extremely high, and collectively, oxygenated species are nearly five times more abundant than non-methane hydrocarbons in the Southern Hemisphere. Current atmospheric models are unable to correctly simulate these findings, suggesting that large, diffuse, and hitherto-unknown sources of oxygenated organic compounds must therefore exist. Although the origin of these sources is still unclear, we suggest that oxygenated species could be formed via the oxidation of hydrocarbons in the atmosphere, the photochemical degradation of organic matter in the oceans, and direct emissions from terrestrial vegetation.

380 citations


Journal ArticleDOI
TL;DR: The results of the diffusion experiments indicate that there is a close relationship between total porosity and the effective diffusion coefficient of a rock (analogous to Archie's Law), and the tortousity factor can be expressed as a function oftotal porosity.

345 citations


Journal ArticleDOI
TL;DR: It is recommended that secondary production rates of Calanus finmarchicus and possibly other lipid-storing copepods not be estimated from egg production mea- surements alone, as has been suggested for other species of copepod, because growth, including structural growth, is not equivalent for all stages.
Abstract: Development rates, nitrogen- and carbon-specific growth rates, size, and condition were determined for the copepod Calanus finmarchicus reared at 3 temperatures (4, 8, and 12°C) at non-limiting food concentrations and 2 limiting food concentrations at 8°C in the laboratory. Devel- opment rates were equiproportional, but not isochronal. Naupliar stage durations were similar, except for non-feeding stages, which were of short duration, and the first feeding stage, which was prolonged, while copepodite stage durations increased with increasing stage of development. Under limiting food concentrations at 8°C, development rates were prolonged but similar relative patterns in stage durations were observed. Body size (length and weight) was inversely related to temperature and positively related to food concentration. Condition measurements were not affected by tempera- ture, but were positively related to food concentration. Growth rates increased with increasing tem- perature and increased asymptotically with increasing food concentration. At high food concentra- tions, growth rates of naupliar stages were high (except for individuals molting from the final naupliar stage to the first copepodite stage, in which growth rates were depressed), while growth of copepodites decreased with increasing stage of development. Neither nitrogen nor carbon growth rates, the former a proxy for structural growth, were exponential over the entire life cycle, but rather sigmoidal. Carbon-specific growth rates were greater than nitrogen-specific growth rates, and this difference increased with increasing stage of development, reflecting an augmentation in lipid depo- sition in the older stages. However, nitrogen and carbon growth rates were more similar under food- limited conditions. Based on this study, we recommend that secondary production rates of Calanus finmarchicus and possibly other lipid-storing copepods not be estimated from egg production mea- surements alone, as has been suggested for other species of copepods, because growth, including structural growth, is not equivalent for all stages.

321 citations


Journal ArticleDOI
TL;DR: A proactive home-based stage-matched expert system smoking cessation program can produce both high participation rates and relatively high abstinence rates.

317 citations


Journal ArticleDOI
TL;DR: Results indicate that experiencing peer rejection in elementary school and greater involvement with antisocial peers in early adolescence are correlated but that these peer relationship experiences may represent two different pathways to adolescent externalizing behavior problems.
Abstract: A longitudinal, prospective design was used to examine the roles of peer rejection in middle childhood and antisocial peer involvement in early adolescence in the development of adolescent externalizing behavior problems. Both early starter and late starter pathways were considered. Classroom sociometric interviews from ages 6 through 9 years, adolescent reports of peers' behavior at age 13 years, and parent, teacher, and adolescent self-reports of externalizing behavior problems from age 5 through 14 years were available for 400 adolescents. Results indicate that experiencing peer rejection in elementary school and greater involvement with antisocial peers in early adolescence are correlated but that these peer relationship experiences may represent two different pathways to adolescent externalizing behavior problems. Peer rejection experiences, but not involvement with antisocial peers. predict later externalizing behavior problems when controlling for stability in externalizing behavior. Externalizing problems were most common when rejection was experienced repeatedly. Early externalizing problems did not appear to moderate the relation between peer rejection and later problem behavior. Discussion highlights multiple pathways connecting externalizing behavior problems from early childhood through adolescence with peer relationship experiences in middle childhood and early adolescence.

311 citations


Journal ArticleDOI
TL;DR: In this article, an accurate three-dimensional numerical model, applicable to strongly non-linear waves, is proposed, where boundary geometry and field variables are represented by 16-node cubic ‘sliding’ quadrilateral elements, providing local inter-element continuity of the first and second derivatives.
Abstract: An accurate three-dimensional numerical model, applicable to strongly non-linear waves, is proposed. The model solves fully non-linear potential flow equations with a free surface using a higher-order three-dimensional boundary element method (BEM) and a mixed Eulerian–Lagrangian time updating, based on second-order explicit Taylor series expansions with adaptive time steps. The model is applicable to non-linear wave transformations from deep to shallow water over complex bottom topography up to overturning and breaking. Arbitrary waves can be generated in the model, and reflective or absorbing boundary conditions specified on lateral boundaries. In the BEM, boundary geometry and field variables are represented by 16-node cubic ‘sliding’ quadrilateral elements, providing local inter-element continuity of the first and second derivatives. Accurate and efficient numerical integrations are developed for these elements. Discretized boundary conditions at intersections (corner/edges) between the free surface or the bottom and lateral boundaries are well-posed in all cases of mixed boundary conditions. Higher-order tangential derivatives, required for the time updating, are calculated in a local curvilinear co-ordinate system, using 25-node ‘sliding’ fourth-order quadrilateral elements. Very high accuracy is achieved in the model for mass and energy conservation. No smoothing of the solution is required, but regridding to a higher resolution can be specified at any time over selected areas of the free surface. Applications are presented for the propagation of numerically exact solitary waves. Model properties of accuracy and convergence with a refined spatio-temporal discretization are assessed by propagating such a wave over constant depth. The shoaling of solitary waves up to overturning is then calculated over a 1:15 plane slope, and results show good agreement with a two-dimensional solution proposed earlier. Finally, three-dimensional overturning waves are generated over a 1:15 sloping bottom having a ridge in the middle, thus focusing wave energy. The node regridding method is used to refine the discretization around the overturning wave. Convergence of the solution with grid size is also verified for this case. Copyright © 2001 John Wiley & Sons, Ltd.

Journal ArticleDOI
TL;DR: The Transtheoretical Model has the potential to do for organizational change what it has done for individual behavior change and conceptually the stages-of-change dimension can be used to integrate principles and processes of change from divergent models of change.
Abstract: Several authors have reflected on the underdeveloped state of organizational change theory, research, and practice. This field needs an integrative framework that can synthesize major approaches to change. The Transtheoretical Model has the potential to do for organizational change what it has done for individual behavior change. Conceptually the stages-of-change dimension can be used to integrate principles and processes of change from divergent models of change. Practically, the stages-of-change dimension can be applied by leaders to reduce resistance, increase participation, reduce dropout, and increase change progress among employees.

Journal ArticleDOI
TL;DR: The findings demonstrate the unique and relative contribution of active and passive social influences and provide limited support for a hypothesized process by which social factors influence cognitions and alcohol-related behaviors.
Abstract: Objective: Social influences are among the most robust predictors of adolescent substance use and misuse. Studies with early adolescent samples have supported the need to distinguish among various types of social influences to better delineate relations between social factors and alcohol use and problems. Method: The first major goal of the present study (N = 399, 263 women) was to examine unique relations between particular facets of social influence and alcohol use and problems in a relatively heavy-drinking population (i.e., college students). We hypothesized that active social influences (offers to drink alcohol) and passive social influences (social modeling and perceived norms) would demonstrate positive associations with measures of alcohol use and problems. We also tested the hypothesis that alcohol outcome expectancies would mediate associations between social influences and drinking behaviors. Results: Structural equation modeling analyses provided strong support for the first hypothesis. Social...

Journal ArticleDOI
TL;DR: McCrane et al. as discussed by the authors proposed an integrated theory of parent involvement in family support programs, which integrates relevant factors within four distinct domains: individual, program, provider, and neighborhood.
Abstract: FEATURE ARTICLE Parent Involvement in Family Support Programs: An Integrated Theory* This article outlines a conceptual model of parental involvement in family support programs, anchored in ecological and family systems frameworks. After summarizing the current attrition literature, the article proposes that parental decisions to enroll and remain in support programs are shaped by a variety of factors at different "levels" of influence: individual characteristics of the parent and family, provider attributes, program characteristics, and neighborhood characteristics. The conclusion discusses the implications of this line of study for research, practice, and policy. Key Words: attrition theory, family support programs, parent involvement. Many can agree on the need to cast a broad net in examining how a vulnerable infant becomes a responsible adult. Few can agree on the most salient factors, however, and, most important for our purpose, how to manipulate these factors so as to increase the likelihood that parents will seek out and effectively utilize the supports they need to better care for their children. Family support programs now abound to help parents with their daily struggles, yet providers often cannot fill all program slots nor keep parents consistently involved for any length of time. Because the dual issues of low enrollment and retention in voluntary, family support programs are endemic to the family support field (Clinton, 1992; Lyons-Ruth, Connell, Grunebaum, & Botein, 1990, Marcenko & Spence, 1994; McCurdy & Jones, 2000; Olds & Kitzman, 1993; Ramey et al., 1992; Seigel, Bauman, Schaefer, Saunders, & Ingram, 1980; Seitz, Rosenbaum, & Apfel, 1985), the need to establish a strong, theoretically driven research base to explain these outcomes is urgent. Attrition, broadly defined here as premature departure from services, has been examined across a variety of family-related contexts, including the home, school, and community. Most studies examine correlates of attrition (i.e., factors observed to have some type of relationship to dropping out; Bean, 1982; Harris, 1998). This approach produces a laundry list of factors that may influence parent involvement but relatively little direction about the individual determinants or cluster of factors that play the most prominent role. In the family support field, literature reviews note several attrition correlates at both the provider and parent level (Clark & Winje, 1998; McCurdy, Hurvis, & Clark, 1996). To date, these studies have failed to integrate these factors into a coherent and testable theory. Although the absence of a theory to explain attrition is not specific to the family support field (cf., Harris), it has hindered the ability of voluntary support programs to develop the types of programmatic and policy reforms necessary for enhancing their enrollment and retention rates. If we know why and how individuals make decisions to use voluntary services, we can begin to form new approaches to service delivery that increase retention rates and the effectiveness of parenting programs. This article addresses the need for a conceptual framework by proposing a theory of parent involvement in family support programs. We begin by reviewing the current attrition literature to identify the multiple influences on enrollment and retention. Borrowing from the work of health behavior theorists, we next develop an ecological theory that integrates relevant factors within four distinct domains--individual, program, provider, and neighborhood. The conclusion discusses the implications of this line of study for research, practice, and policy. The Empirical Context Despite growing interest in understanding the wide range of domains that influence human behavior, current efforts to investigate attrition have suffered from a restricted conceptual framework both in terms of the areas explored and in the definition of the engagement process. …

Journal ArticleDOI
TL;DR: It is hypothesized that CAP, a large joint arthropathy, may be associated with ineffective boundary lubrication provided by synovial fluid, and both SZP and lubricin occupy a new class of biomolecules termed tribonectins.

Journal ArticleDOI
TL;DR: In this article, the role of the board of directors, the audit committee, and the executive committee in preventing earnings management was examined, and they concluded that board and audit committee activity and their members' financial sophistication may be important factors in constraining the propensity of managers to engage in earnings management.
Abstract: We examine the role of the board of directors, the audit committee, and the executive committee in preventing earnings management. Supporting an SEC Panel Report's conclusion that audit committee members need financial sophistication, we show that the composition of a board in general and of an audit committee more specifically, is related to the likelihood that a firm will engage in earnings management. Board and audit committee members with corporate or financial backgrounds are associated with firms that have smaller discretionary current accruals. Board and audit committee meeting frequency is also associated with reduced levels of discretionary current accruals. We conclude that board and audit committee activity and their members' financial sophistication may be important factors in constraining the propensity of managers to engage in earnings management.

Journal ArticleDOI
TL;DR: In this article, the authors examined the quality of evidence supporting these assertions and found that fishers would not leave fishing for an alternative occupation, citing income as well as non-income factors for resisting the change.

Journal ArticleDOI
TL;DR: In this paper, a standardized method for assessing direct economic expenditures and impacts associated with tourist events is presented, which addresses critical and often overlooked methodological issues that distinguish analysis of impacts from tourism in general and analysis of impact from tourist events.
Abstract: This article outlines a standardized method for assessing direct economic expenditures and impacts associated with tourist events. The method addresses critical and often overlooked methodological issues that distinguish analysis of impacts from tourism in general and analysis of impacts from tourist events. These issues involve a common failure to account for sources, origins, destinations, and causes of expenditures. The corresponding errors in impact estimation will carry through into subsequent input-output or multiplier models and are of particular significance when one considers impacts of tourism events in regions dominated by other tourist sites or attractions, such as heavily visited coastal communities. Implications of the framework for impact estimation are illustrated using examples drawn from recent Rhode Island tourist events, including the 1997 Newport Folk Festival.

Journal ArticleDOI
TL;DR: It is concluded that diet and phenotypic flexibility in both body composition and the digestive system of migratory birds are important in allowing birds to successfully overcome the often-conflicting physiological challenges of migration.
Abstract: Birds during migration must satisfy the high energy and nutrient demands associated with repeated, intensive flight while often experiencing unpredictable variation in food supply and food quality. Solutions to such different challenges may often be physiologically incompatible. For example, increased food intake and gut size are primarily responsible for satisfying the high energy and nutrient demands associated with migration in birds. However, short-term fasting or food restriction during flight may cause partial atrophy of the gut that may limit utilization of ingested food energy and nutrients. We review the evidence available on the effects of long- and short-term changes in food quality and quantity on digestive performance in migratory birds, and the importance of digestive constraints in limiting the tempo of migration in birds. Another important physiological consequence of feeding in birds is the effect of diet on body composition dynamics during migration. Recent evidence suggests that birds utilize and replenish both protein and fat reserves during migration, and diet quality influences the rate of replenishment of both these reserves. We conclude that diet and phenotypic flexibility in both body composition and the digestive system of migratory birds are important in allowing birds to successfully overcome the often-conflicting physiological challenges of migration.

Journal ArticleDOI
TL;DR: The patterns found across the stages of change were consistent with the theoretical predictions of the TTM and replicated the patterns observed in previous studies.

Journal ArticleDOI
TL;DR: This is the first study to the authors' knowledge that has been effective in reducing objective measures of passive smoke exposure in households with healthy children, and these findings have important implications for pediatric health care providers, who play an important role in working with parents to protect children's health.
Abstract: Objective. Passive smoke exposure among children is widespread in the United States; estimates suggest that almost 40% of children who are younger than 5 years live with a smoker. Few randomized studies of passive smoke exposure reduction among children have been conducted, and the impact of interventions that have been evaluated has been limited. The objective of this study was to determine whether a motivational intervention for smoking parents of young children will lead to reduced household passive smoke exposure. Methods. Project KISS (Keeping Infants Safe From Smoke), a theory-driven exposure reduction intervention targeting low-income families with young children, was a randomized controlled study in which participants—smoking parents/caregivers ( N = 291) who had children who were younger than 3 years and who were recruited through primary care settings—were randomly assigned to either the motivational intervention (MI) or a self-help (SH) comparison condition was used. Follow-up assessments were conducted at 3 and 6 months. The MI condition consisted of a 30- to 45-minute motivational interviewing session at the participant9s home with a trained health educator and 4 follow-up telephone counseling calls. Feedback from baseline household air nicotine assessments and assessment of the participant9s carbon monoxide level was provided as part of the intervention. Participants in the SH group received a copy of the smoking cessation manual, the passive smoke reduction tip sheet, and the resource guide in the mail. Household nicotine levels were measured by a passive diffusion monitor. Results. The 6-month nicotine levels were significantly lower in MI households. Repeated measures analysis of variance across baseline, 3-month, and 6-month time points showed a significant time-by-treatment interaction, whereby nicotine levels for the MI group decreased significantly and nicotine levels for the SH group increased but were not significantly different from baseline. Conclusions. This study targeted a large sample of racially and ethnically diverse low-income families, in whom both exposure and disease burden is likely to be significant. This is the first study to our knowledge that has been effective in reducing objective measures of passive smoke exposure in households with healthy children. These findings have important implications for pediatric health care providers, who play an important role in working with parents to protect children9s health. Providers can help parents work toward reducing household passive smoke exposure using motivational strategies and providing a menu of approaches regardless of whether the parents are ready to quit.

Journal ArticleDOI
TL;DR: Moore et al. as mentioned in this paper presented new insights into deformation and fluid flow processes in the Nankai Trough accretionary prism, using the results of Ocean Drilling Program Leg 190.
Abstract: Moore, G. F., Taira, A., Klaus, A., Becker, L., Boeckel, B., Cragg, B. A., Dean, A., Fergusson, C. L., Henry, P., Hirano, S., Hisamitsu, T. et al. (2001). New insights into deformation and fluid flow processes in the Nankai Trough accretionary prism: Results of Ocean Drilling Program Leg 190. Geochemistry, Geophysics, Geosystems, 2, Article No: 2001GC000166.

Journal ArticleDOI
TL;DR: In this article, the authors describe the economic dimension of the virtual water concept as an application of comparative advantage, with particular emphasis on water as the key factor of production and extend the discussion of virtual water by describing a nation's goals regarding food security within a broader framework that includes other objectives such as providing national security, promoting economic growth, and improving the quality of life for citizens.

Journal ArticleDOI
29 Jun 2001-Science
TL;DR: Results indicate that the interaction between buoyantly upwelling diapirs and subduction-induced flow in the mantle creates a network of low-density, low-viscosity conduits through which buoyant flow is rapid, yielding transport times commensurate with those indicated by uranium-thorium studies.
Abstract: Recent geochemical studies of uranium-thorium series disequilibrium in rocks from subduction zones require magmas to be transported through the mantle from just above the subducting slab to the surface in as little as ∼30,000 years. We present a series of laboratory experiments that investigate the characteristic time scales and flow patterns of the diapiric upwelling model of subduction zone magmatism. Results indicate that the interaction between buoyantly upwelling diapirs and subduction-induced flow in the mantle creates a network of low-density, low-viscosity conduits through which buoyant flow is rapid, yielding transport times commensurate with those indicated by uranium-thorium studies.

Journal ArticleDOI
TL;DR: In this article, a model- predicted sequence of transitions (bifurcations) in the dynamic behavior of a population from stable equilibria to quasiperiodic and periodic cycles to chaos to three-cycles using cultures of the flour beetle Tribolium.
Abstract: A defining hypothesis of theoretical ecology during the past century has been that population fluctuations might largely be explained by relatively low-dimensional, non- linear ecological interactions, provided such interactions could be correctly identified and modeled. The realization in recent decades that such nonlinear interactions might result in chaos and other exotic dynamic behaviors has been exciting but tantalizing, in that attri- buting the fluctuations of a particular real population to the complex dynamics of a particular mathematical model has proved to be an elusive goal. We experimentally tested a model- predicted sequence of transitions (bifurcations) in the dynamic behavior of a population from stable equilibria to quasiperiodic and periodic cycles to chaos to three-cycles using cultures of the flour beetle Tribolium. The predictions arose from a system of difference equations (the LPA model) describing the nonlinear life-stage interactions, predominantly cannibalism. We built a stochastic version of the model incorporating demographic vari- ability and obtained conditional least-squares estimates for the model parameters. We gen- erated 2000 ''bootstrapped data sets'' with a time-series bootstrap technique, and for each set we reestimated the model parameters. The resulting 2000 bootstrapped parameter vectors were used to obtain confidence intervals for the model parameters and estimated distri- butions of the Liapunov exponents for the deterministic portion (the skeleton) of the model as well as for the full stochastic model. Frequency distributions of estimated dynamic behaviors of the skeleton at each experimental treatment were produced. For one treatment, over 83% of the bootstrapped parameter estimates corresponded to chaotic attractors, and the remainder of the estimates yielded high-period cycles. The low-dimensional skeleton accounted for at least 90% of the variability in the population abundances and accurately described the responses of populations to experimental demographic manipulations, in- cluding treatments for which the predicted dynamic behavior was chaos. Demographic stochasticity described the remaining noise quite well. We conclude that the fluctuations of experimental flour beetle populations are explained largely by known nonlinear forces involving cannibalistic-stage interactions. Claims of dynamic behavior such as periodic cycles or chaos must be accompanied by a consideration of the reliability of the estimated parameters and a realization that the population fluctuations are a blend of deterministic forces and stochastic events.

Book ChapterDOI
TL;DR: This work proposes a set of specific hypotheses that help to guide future research on the feeding biology of sharks, and suggests that similar hydrodynamic constraints in bony fishes and sharks result in convergent morphological and functional specializations for suction feeding in both groups.
Abstract: Sharks as a group have a long history as highly successful predatory fishes. Although, the number of recent studies on their diet, feeding behavior, feeding mechanism, and mechanics have increased, many areas still require additional investigation. Dietary studies of sharks are generally more abundant than those on feeding activity patterns, and most of the studies are confined to relatively few species, many being carcharhiniform sharks. These studies reveal that sharks are generally asynchronous opportunistic feeders on the most abundant prey item, which are primarily other fishes. Studies of natural feeding behavior are few and many observations of feeding behavior are based on anecdotal reports. To capture their prey sharks either ram, suction, bite, filter, or use a combination of these behaviors. Foraging may be solitary or aggregate, and while cooperative foraging has been hypothesized it has not been conclusively demonstrated. Studies on the anatomy of the feeding mechanism are abundant and thorough, and far exceed the number of functional studies. Many of these studies have investigated the functional role of morphological features such as the protrusible upper jaw, but only recently have we begun to interpret the mechanics of the feeding apparatus and how it affects feeding behavior. Teeth are represented in the fossil record and are readily available in extant sharks. Therefore much is known about their morphology but again functional studies are primarily theoretical and await experimental analysis. Recent mechanistic approaches to the study of prey capture have revealed that kinematic and motor patterns are conserved in many species and that the ability to modulate feeding behavior varies greatly among taxa. In addition, the relationship of jaw suspension to feeding behavior is not as clear as was once believed, and contrary to previous interpretations upper jaw protrusibility appears to be related to the morphology of the upper jaw-chondrocranial articulation rather than the type of jaw suspension. Finally, we propose a set of specific hypotheses including: (1) The functional specialization for suction feeding hypothesis that morphological and functional specialization for suction feeding has repeatedly arisen in numerous elasmobranch lineages, (2) The aquatic suction feeding functional convergence hypothesis that similar hydrodynamic constraints in bony fishes and sharks result in convergent morphological and functional specializations for suction feeding in both groups, (3) The feeding modulation hypothesis that suction capture events in sharks are more stereotyped and therefore less modulated compared to ram and bite capture events, and (4) The independence of jaw suspension and feeding behavior hypothesis whereby the traditional categorization of jaw suspension types in sharks is not a good predictor of jaw mobility and prey capture behavior. Together with a set of questions these hypotheses help to guide future research on the feeding biology of sharks.

Journal ArticleDOI
TL;DR: Benefits associated with delayed clamping in preterm infants included higher hematocrit and hemoglobin levels, blood pressure, and blood volume, with better cardiopulmonary adaptation and fewer days of oxygen and ventilation and fewer transfusions needed.

Journal ArticleDOI
TL;DR: A variety of mathematical programming models, representative of the many ways in which the recycling industry currently operates, have been proposed along with numerical illustrations and can be used by recyclers and processors for optimizing recycling operations and thus contribute towards the economic sustainability of electronics recycling.
Abstract: Increasing environmental concerns about the disposal of mass produced products have resulted in efforts to take back end-of-life consumer products. Legislation aimed at forcing manufacturers to take back electronics products at the end of their useful lives has either been adopted or is impending in many countries. This, along with shrinking landfill capacity and the reluctance of communities to open new waste sinks underscores the importance of developing methods and models for the management of end-of-life materials and products. This paper reports a study of the reverse channels for recycling of electronics products. The economics of electronics recycling are modeled from the viewpoints of the generators, recyclers, and material processors separately. A variety of mathematical programming models, representative of the many ways in which the recycling industry currently operates, have been proposed along with numerical illustrations. Models integrating disassembly and material recovery decisions are also presented. These models can be used by recyclers and processors for optimizing recycling operations and thus contribute towards the economic sustainability of electronics recycling.

Journal ArticleDOI
TL;DR: This work derives explicit definitions of fractional convolution and correlation operations in a systematic and comprehensive manner and provides alternative formulations of those fractional operations that suggest efficient algorithms for discrete implementation.
Abstract: Using operator theory methods together with our previously introduced unitary fractional operator, we derive explicit definitions of fractional convolution and correlation operations in a systematic and comprehensive manner. Via operator manipulations, we also provide alternative formulations of those fractional operations that suggest efficient algorithms for discrete implementation. Through simulation examples, we demonstrate how well the proposed efficient method approximates the continuous formulation of fractional autocorrelation. It is also shown that the proposed fractional autocorrelation corresponds to radial slices of the ambiguity function (AF). We also suggest an application of the fast fractional autocorrelation for detection and parameter estimation of linear FM signals.

Journal ArticleDOI
TL;DR: In this paper, the effects of message framing on beliefs, attitudes, and behaviors relevant to cigarette smoking were examined. But, they focused on the benefits of adopting a health behavior rather than the risks of not adopting it (losses).
Abstract: Persuasive health messages can be framed to emphasize the benefits of adopting a health behavior (gains) or the risks of not adopting it (losses). This study examined the effects of message framing on beliefs, attitudes, and behaviors relevant to cigarette smoking. In video presentations about tobacco smoking, visual images and auditory voiceover content were framed either as gains or losses, yielding 4 message conditions. Undergraduates (N= 437) attending a public university in New England were assigned randomly to view one of these messages. Gain-framed messages about smoking in visual and auditory modalities shifted smoking-related beliefs, attitudes, and behaviors in the direction of avoidance and cessation. Health-communication experts, when promoting prevention behaviors like smoking avoidance or cessation, may wish to diverge from the tradition of using loss-framed messages and fear appeals in this domain, and instead consider using gain-framed appeals that present the advantages of not smoking.