Showing papers by "University of Rhode Island published in 1994"
01 Jan 1994
619 citations
TL;DR: Two principles for progressing from the precontemplation stage of change to the action stage were discovered and Discussion focuses on the implications of these principles for individual psychology and public health policy.
Abstract: Two principles for progressing from the precontemplation stage of change to the action stage were discovered. The strong principle states that progression from precontemplation to action is a function of approximately a 1 standard deviation increase in the pros of a health behavior change. The weak principle states that progression from precontemplation to action is a function of approximately a 1/2 standard deviation decrease in the cons of a health behavior change. In Study 1, these principles were derived from cross-sectional data on 12 problem behaviors relating the pros and cons of changing to the stages of change. In Study 2, these principles were validated on cross-sectional data from an independent sample of 1,466 smokers. Discussion focuses on the implications of these principles for individual psychology and public health policy.
522 citations
TL;DR: The global distribution pattern of coccolithophrid blooms was mapped in order to ascertain the prevalence of these blooms in the world oceans and to estimate their worldwide production of CaCO3 and dimethyl sulfide (DMS) as mentioned in this paper.
Abstract: The global distribution pattern of coccolithophrid blooms was mapped in order to ascertain the prevalence of these blooms in the world's oceans and to estimate their worldwide production of CaCO3 and dimethyl sulfide (DMS). Mapping was accomplished by classifying pixels of 5-day global composites of coastal zone color scanner imagery into bloom and nonbloom classes using a supervised, multispectral classification scheme. Surface waters with the spectral signature of coccolithophorid blooms annually covered an average of 1.4 x 10(exp 6) sq km in the world oceans from 1979 to 1985, with the subpolar latitudes accounting for 71% of this surface area. Classified blooms were most extensive in the Subartic North Atlantic. Large expanses of the bloom signal were also detected in the North Pacific, on the Argentine shelf and slope, and in numerous lower latitude marginal seas and shelf regions. The greatest spatial extent of classified blooms in subpolar oceanic regions occurred in the months from summer to early autumn, while those in lower latitude marginal seas occurred in midwinter to early spring. Though the classification scheme was effcient in separating bloom and nonbloom classes during test simulations, and biogeographical literature generally confirms the resulting distribution pattern of blooms in the subpolar regions, the cause of the bloom signal is equivocal in some geographic areas, particularly on shelf regions at lower latitudes. Standing stock estimates suggest that the presumed Emiliania huxleyi blooms act as a significant source of calcite carbon and DMS sulfur on a regional scale. On a global scale, however, the satellite-detected coccolithophorid blooms are estimated to play only a minor role in the annual production of these two compounds and their flux from the surface mixed layer.
504 citations
TL;DR: The transtheoretical model of health behavior change is described and supporting empirical work is presented that reviews the central constructs of the model: the stages of change, processes ofchange, decisional balance, confidence, and temptation.
Abstract: The transtheoretical model of health behavior change is described and supporting empirical work is presented that reviews the central constructs of the model: the stages of change, processes of change, decisional balance, confidence, and temptation. Model-based applications to a broad range of problem behaviors are summarized. Applications to human immunodeficiency virus (HIV) prevention behavior changes are highlighted for each variable. Finally, several questions about the area of sexual behavior change to reduce risk of HIV exposure are explored and future research ideas are described within the context of this model.
486 citations
TL;DR: This paper explored links between Greenland and Antarctic climate during the last glaciation using a high-resolution chronology derived by correlating oxygen isotope data for trapped O2 in the GISP2 and Vostok cores.
Abstract: THE ice cores recovered from central Greenland by the GRIP1,2 and GISP23 projects record 22 interstadial (warm) events during the part of the last glaciation spanning 20–105 kyr before present. The ice core from Vostok, east Antarctica, records nine interstadials during this period4,5. Here we explore links between Greenland and Antarctic climate during the last glaciation using a high-resolution chronology derived by correlating oxygen isotope data for trapped O2 in the GISP2 and Vostok cores. We find that interstadials occurred in east Antarctica whenever those in Greenland lasted longer than 2,000 years. Our results suggest that partial deglaciation and changes in ocean circulation are partly responsible for the climate teleconnection between Greenland and Antarctica. Ice older than 115 kyr in the GISP2 core shows rapid variations in the δ18O of O2 that have no counterpart in the Vostok record. The age–depth relationship, and thus the climate record, in this part of the GISP2, core appears to be significantly disturbed.
443 citations
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TL;DR: In this article, the authors present photographs and measurements from satellites, aircraft, ships and the Space Shuttle Atlantis which show dramatic biological responses to circulation and mixing processes associated with an open-ocean front.
Abstract: THE ocean has considerable spatial and temporal heterogeneity in biomass and productivity owing in part to the effects of ocean circulation and mixing1,2. Water mass boundaries (fronts) in coastal waters are well-known sites of enhanced biological activity3,4. Comparatively little is known of open-ocean fronts, and one of the few biological studies of an oceanic front showed phytoplankton biomass at only slightly higher densities than in surrounding waters5. Here we present photographs and measurements from satellites, aircraft, ships and the Space Shuttle Atlantis which show dramatic biological responses to circulation and mixing processes associated with an open-ocean front. Breaking waves (whitecaps) caused by water turbulence and mixing, and very dark green water caused by extremely high concentrations (>20 mg of chlorophyll a per m3) of buoyant diatoms (Rhizosolenia sp.) made a distinct line in the sea visible for hundreds of kilometres. The line traced the northern edge of a westward-progagating (50 km per day) tropical instability wave (1,000-km wavelength) delineating the boundary between cold, upwelled waters and warmer waters to the north. High phytoplankton biomass and primary production associated with the extensive diatom patches may explain anecdotal observations of high animal abundance along this frontal boundary.
323 citations
TL;DR: The authors found that community service work along with discussion of relevant moral issues is an effective means of moving students into the post-conventional stage of principled moral reasoning, as measured by Rest's Defining Issues Test.
Abstract: A study designed to test the effect of community service work on college ethics students found that community service work along with discussion of relevant moral issues is an effective means of moving students into the post‐conventional stage of principled moral reasoning, as measured by Rest's Defining Issues Test. Other benefits of community service work are also discussed in the paper.
310 citations
TL;DR: In this paper, the authors examined the stages of readiness to exercise and their relationship to self-efficacy, the costs and benefits of exercising, and self-report of physical activity in a sample of Rhode Island worksites.
Abstract: Exercise has important health benefits but a large proportion of the population is physically inactive. We examined the stages of readiness to exercise and their relationship to self-efficacy, the costs and benefits of exercising, and self-report of physical activity in a sample of Rhode Island worksites. Using a three-step model-building approach, exploratory principal components analyses were followed by an examination of the stages of change model with confirmatory structural equation modeling procedures. The model was then examined with longitudinal data. Confirmatory and longitudinal analyses showed an excellent tit between the model and the data. Results indicated that the costs and benefits of exercise and self-efficacy for exercise were related to physical activity only indirectly, through the mediation of stage of readiness to exercise. Structural modeling fit indices revealed that much of the variation and covariation in physical activity was explained by the model. There is the potential to enhance the impact of exercise interventions, by targeting them so as to address factors related to these different stages of readiness.
299 citations
TL;DR: The new oral controlled-release system shows, at least in vitro, good characetristics in relation to three parameters: controlled release of the drug, bioadhesiveness in the stomach and intestine of rabbits and buoyancy in an acid medium.
269 citations
TL;DR: In this paper, a hybrid mixing scheme based jointly on the Kraus-Turner-type mixed layer model and Price's dynamic instability model is introduced to aid in parameterization of vertical turbulent mixing in numerical ocean models.
Abstract: A novel hybrid vertical mixing scheme, based jointly on the Kraus–Turner-type mixed layer model and Price's dynamic instability model, is introduced to aid in parameterization of vertical turbulent mixing in numerical ocean models. The scheme is computationally efficient and is capable of simulating the three major mechanisms of vertical turbulent mixing in the upper ocean, that is, wind stirring, shear instability, and convective overturning. The hybrid scheme is first tested in a one-dimensional model against the Kraus–Turner-type bulk mixed layer model and the Mellor–Yamada level 2.5 (MY2.5) turbulence closure model. As compared with those two models, the hybrid model behaves more reasonably in both idealized experiments and realistic simulations. The improved behavior of the hybrid model can be attributed to its more complete physics. For example, the MY2.5 model underpredicts mixed layer depth at high latitudes due to its lack of wind stirring and penetrative convection, while the Kraus–Turn...
265 citations
TL;DR: Using an accurate formula for the error in approximating a low rank component, the performance of adaptive detection based on reduced-rank nulling is calculated and a generalized likelihood-ratio test (GLRT) is presented for adaptively detecting a lowRank signal in the presence of low rank interference.
Abstract: Using an accurate formula for the error in approximating a low rank component, we calculate the performance of adaptive detection based on reduced-rank nulling. In this principal component inverse (PCI) method, one temporarily regards the interference as a strong signal to be enhanced. The resulting estimate of the interference waveform is subtracted from the observed data, and matched filtering is used to detect signal components in the residual waveform. We also present a generalized likelihood-ratio test (GLRT) for adaptively detecting a low rank signal in the presence of low rank interference. This approach leads to a test which is closely related to the PCI method and extends the PCI method to the case where strong signal components are present in the data. A major accomplishment of the work is our calculation of the statistics of the output of the matched filter for the case in which interference cancellation and signal detection are carried out on the same observed data matrix. That is, no separate data is used for adaptation. Examples are presented using both simulated data and real, active-sonar reverberation data from the ARSRP, the Acoustic Reverberation Special Research Program of the Office of Naval Research. >
TL;DR: In this paper, the impact of Confucianism on the organizational communication in these nations, based on the four key principles of confucian teachings: the hierarchical relationship, the family system, Jen, and the emphasis on education, is explored.
Abstract: Confucianism has been identified as the major cultural factor that explains the economic success of the Asian Five Dragons. This paper explores the impact of Confucianism on the organizational communication in these nations, based on the four key principles of Confucian teachings: the hierarchical relationship, the family system, Jen, and the emphasis on education. This study further discusses the influence of these four principles of Confucianism on management behaviors and communication in the organization. Implications of Confucianism influence on organizational communication are also explained.
TL;DR: The results suggest that smokers are a particularly important target for health promotion interventions, and it may be possible to make initial contact with them through other health programs at the worksite, as well as mediators such as motivation for change.
01 May 1994
TL;DR: In this paper, the authors use biological simulation modelling as a tool for the analysis of spring plankton blooms in shallow, coastal waters in temperate latitudes of the North Atlantic, and show that interannual variability in bloom initiation arises from year-to-year differences in incident irradiation, as determined by weather.
Abstract: Established conceptual models of the initiation and progression of spring phytoplankton blooms are reconsidered in light of recent observations We use biological simulation modelling as a tool for the analysis of spring plankton blooms in shallow, coastal waters in temperate latitudes of the North Atlantic The model shows that interannual variability in the timing of bloom initiation arises from year-to-year differences in incident irradiation, as determined by weather (cloudiness) This variability in timing results in some years when the spring bloom occurs in cold water temperatures near 0°C Model results suggest that due to low temperature inhibition of heterotrophic consumption, more fresh organic material is delivered to the benthos in these cold-water blooms than when the bloom occurs in waters only 3°C warmer Thus we suggest that variable bloom timing can be important to the trophodynamic fate of bloom products We suggest that variability in timing of spring phytoplankton blooms in offshore and open ocean waters is also related to weather, through controls on the light field and wind mixing Our analyses of wind-driven vertical mixing demonstrate such blooms can begin following the winter period of deep convection, and prior to the vernal development of stratification, provided that wind speed is below a certain, predictable threshold, which we estimate In such cases, there may be several spring bloom pulses, each interrupted by self-shading light limitation or vertical mixing events Eventually the seasonal thermocline develops and nutrient exhaustion curtails bloom production This means that the spring phytoplankton bloom in offshore and open ocean areas may be significantly more productive, result in more export production, and be more important to the carbon cycle, than has been previously assumed Furthermore, these features of temperate marine planktonic ecosystems are not only sensitive to annual variations in weather, but also any trends that might result from greenhouse warming or other factors that affect the climate system
TL;DR: In this article, structural equation modeling (SEM) is discussed in relation to the conditions necessary for providing causal evidence, and the weaknesses and the strengths of the method are examined.
Abstract: As the use of structural equation modeling (SEM) has increased, confusion has grown concerning the correct use of and the conclusions that can be legitimately drawn from these methodologies. It appears that much of the controversy surrounding SEM is related to the degree of certainty with which causal statements can be drawn from these procedures. SEM is discussed in relation to the conditions necessary for providing causal evidence. Both the weaknesses and the strengths of SEM are examined. Although structural modeling cannot ensure that necessary causal conditions have been met, it is argued that SEM methods may offer the potential for tentative causal inferences to be drawn when used with carefully specified and controlled designs. Keeping in mind that no statistical methodology can in and of itself determine causality, specific guidelines are suggested to help researchers approach a potential for providing causal evidence with SEM procedures.
TL;DR: The Behavioral algorithm determines stage of change for fat reduction to < or = 30% of energy in populations with high fat intakes and could be used in dietary counseling to tailor interventions to a patient's stage ofchange.
Abstract: Objective To develop an algorithm that defines a person's stage of change for fat intake ≤30% of energy. The Stages of Change Model describes when and how people change problem behaviors; change is defined as a dynamic variable with five discrete stages. Design A stage of change algorithm for determining dietary fat intake ≤30% of energy was developed using one sample and was validated using a second sample. Subjects Sample 1 was a random sample of 614 adults who responded to mailed questionnaires. Sample 2 was a convenience sample of 130 faculty, staff, and graduate students. Statistics Subjects in sample 1 were initially classified in a stage of change using an algorithm based on their behavior related to avoiding high-fat foods. Dietary markers were selected for a Behavioral algorithm using logistic regression analyses. Sensitivity, specificity, and predictive value of the Behavioral algorithm were determined, then compared between samples using the Z test. Results The following dietary markers predicted intake ≤30% of fat ( Ξ 2 = 131; P 30% of energy from fat with 93% specificity in sample 1 and 87% in sample 2 ( Z = 1.36; P > .05). Predictive value was also validated; 64% and 58% of subjects meeting the behavioral criteria had fat intakes ≤30% of energy ( Z = 1.1; P > .05). The algorithm was not sensitive, however; most subjects with fat intakes ≤30% of energy from fat failed to meet the behavioral criteria. The sensitivity differed between samples 1 and 2 (44% and 27%, respectively; Z = 3.84; P Applications The Behavioral algorithm determines stage of change for fat reduction to ≤30% of energy in populations with high fat intakes. The algorithm could be used in dietary counseling to tailor interventions to a patient's stage of change.
TL;DR: In this article, primary and secondary amines are rapidly labelled by 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate to form highly fluorescent asymmetric urea derivatives which are readily amenable to analysis by liquid chromatography.
TL;DR: The results demonstrate that FA oxidation of SHR hearts is profoundly suppressed relative to that of the normotensive SD strain, particularly at high workloads, consistent with the hypothesis that a shift away from FA use toward glucose contributes to the preservation of energetic economy in stable, concentric LVH.
TL;DR: In this article, anoxic control cores were used to provide continuous checks on the magnitude of porewater de-gassing rates, and allowed measured rates of total N 2 flux to be corrected for this background flux.
Abstract: Nitrogen gas flux was measured from sediments taken from Narragansett Bay, Rhode Island, Boston Harbour, Massachusetts, and the Pawcatuck River Estuary, Rhode Island In addition to studies of field cores taken directly from these systems, intact sediments were taken from Narragansett Bay and maintained in control and nutrient enriched mesocosms Sediment denitrification was measured as a flux of N 2 gas from sediments in N 2 -free chambers The advantages of this technique are that it allows for the direct measurement of denitrification in undisturbed sediment cores under ambient conditions of dissolved nutrients, oxygen, and temperature The challenge of this technique has been to correctly distinguish between N 2 fluxes produced by denitrification activity and fluxes of N 2 caused by sediment porewater de-gassing In this study, anoxic 'control' cores were used to provide continuous checks on the magnitude of porewater de-gassing rates, and allowed measured rates of total N 2 flux to be corrected for this background flux The use of anoxic control cores allowed measurements to begin soon after core collection, without the need for long pre-incubations Observed rates of sediment denitrification ranged from 0 to 195 μmol N 2 m -2 h -1 Highest rates were found in the enriched mesocosms and at a sewage outfall site in Boston Harbour Denitrification rates increased exponentially with temperature and were enhanced by added nutrients Results from the anoxic control cores showed that even after 10 days, the background flux of N 2 from de-gassing porewaters (10-34 μmol N 2 m -2 h -1 ) remained a significant fraction of the overall N 2 flux Although rates of sediment denitrification were stimulated by added nutrients, the overall percentage loss of N from these systems through denitrification did not keep pace with N enrichment, generally accounting for less than 20% of N inputs Thus denitrification may not necessarily provide a significant pathway for alleviating eutrophication effects in coastal waters
TL;DR: Diverse clinical specialties of nursing have already proven fertile areas for phenomenological research such as medical-surgical, maternal-child, gerontological, and emergency room nursing.
TL;DR: In this paper, the authors examined the incidence of violence toward women and risk factors for violence towards women in black families and analyzed data from the Second National Family Violence Survey (SNFVS).
Abstract: This paper examines the incidence of violence toward women and risk factors for violence toward women in black families. Data from the Second National Family Violence Survey are analyzed. The Secon...
TL;DR: The performance of three groups of children on a battery of executive function tasks was investigated in this article, where a double dissociation paradigm was used to evaluate the performance of children with attention deficit hyperactivity disorder, 34 children with developmental language disorder, and 45 non-abled children.
Abstract: The performance of three groups of children on a battery of executive function tasks was investigated. A double dissociation paradigm was used, including six executive function tasks (Wisconsin Card Sorting Test, Matching Familiar Figures Test, visual search, verbal fluency, Tower of Hanoi, and mazes) and two vocabulary tasks (Peabody Picture Vocabulary Test‐Revised and the Boston Naming Test). Executive function was defined as goal‐directed behavior including strategic planning, impulse control, organized search, and flexibility of thought and action. One hundred and fifteen children, aged 6.0 to 12.11 years, participated in the study (36 children with attention deficit hyperactivity disorder, 34 children with developmental language disorder, and 45 nondisabled children). Four main results were found: (a) groups differed on three of the executive function tasks, (b) groups differed on both of the nonexecutive function tasks, (c) the relationship between age and performance was linear, and (d) discriminan...
TL;DR: Investigating psychosocial factors related to fruit and vegetable consumption to understand better who might be receptive and who might resist the national 5-A-Day campaign implies that stage of readiness to change should be considered as well as other factors in planning interventions for increasing fruit and vegetables consumption.
Abstract: A major national health campaign has recently been initiated to promote consumption of 5 or more servings of fruits and vegetables each day. This paper investigates psychosocial factors related to fruit and vegetable consumption to understand better who might be receptive and who might resist the national 5-A-Day campaign. We studied 405 adult respondents to a random-digit dial telephone survey. Applying the Transtheoretical Model, respondents were classified by stage of readiness to adopt the practice of eating 5 or more fruits and vegetables each day. Logistic regression models were developed for persons consuming 2 or fewer servings daily and for persons in the Precontemplation stage. Education was directly related to fruit and vegetable intake and indirectly related to being in the Precontemplation stage. Males were twice as likely as females to be in the Precontemplation stage and eat fewer than 2 servings a day. Of special interest, respondents with children at home were at greater risk of eating 2 or fewer servings a day than those without children at home (OR = 1.63; 95% CI, 1.06-2.52). These results imply that stage of readiness to change should be considered as well as other factors in planning interventions for increasing fruit and vegetable consumption.
TL;DR: In this paper, the last glacial-interglacial transition of sediment cores from the Academician Ridge region of Lake Baikal, Siberia was used to estimate the age of sediment beyond the range of radiocarbon method.
TL;DR: The children in the two experimental classes receiving training had significantly greater gains in phonological awareness at the end of kindergarten, were significantly more likely to be promoted to first grade rather than to pre-one, and had a trend toward better reading skills in first grade than did the smaller group of children promoted tofirst grade from the control classes.
Abstract: A small-scale, longitudinal, phonological awareness training study with inner-city kindergarten children was conducted in four classrooms. The central goals of the study were the creation and evaluation of a phonological awareness training program and a preliminary look at the consequence of that training on basic phonological processes.
TL;DR: The results strongly suggest that iron availability limits photochemrcal energy conversion efficiency and is the principal mechanism controlling rates of photosynthesis and growth in the nutrient-rich equatorial Pacific.
Abstract: On a transect study in the eastern equatorial Pacific, from the high-nutrient, low-chlorophyll tropical waters to the oligotrophic subtropical waters, we determined the variability in the maximum change in the quantum yield of chlorophyll fluorescence (A&,) by means of a fast repetition rate fluorometer. A& is a quantitative measure of photochemical energy conversion efficiency in photosystem 2, the variability of which is determined by the functional organization of the photosynthetic apparatus. The results revealed that A&,, was relatively low throughout the nutrient-rich equatorial waters, providing unequivocal evidence for physiological limitation of photochemical energy conversion efficiency in the natural phytoplankton populations. Shipboard enrichment studies showed that A&, increased following addition of nanomolar concentrations of inorganic iron as well as aerosol dust added at similar iron concentrations. This response reflects an iron-induced repair of photosystem 2 function in the enclosed bottle community. Low A&, at the top of the Equatorial Undercurrent indicated that the amount of iron upwelled to the surface was insufficient .t,o repair photosystem 2 function. Our results strongly suggest that iron availability limits photochemrcal energy conversion efficiency and is the principal mechanism controlling rates of photosynthesis and growth in the nutrient-rich equatorial Pacific.
TL;DR: In a constrained finger-tapping task, interresponse interval (IRI) was a nonlinear function of interstimulus interval (ISI), in agreement with the results of Collyer, Broadbent, and Church (1992).
Abstract: In a constrained finger-tapping task, in which a subject attempts to match the rate of tapping responses to the rate of a pacer stimulus, interresponse interval (IRI) was a nonlinear function of interstimulus interval (ISI), in agreement with the results of Collyer, Broadbent, and Church (1992). In an unconstrained task, the subjects were not given an ISI to match, but were instructed to tap at their preferred rate, one that seemed not too fast or too slow for comfortable production. The distribution of preferred IRIs was bimodal rather than unimodal, with modes at 272 and 450 msec. Preferred IRIs also tended to become shorter over successive sessions. Time intervals that were preferred in the unconstrained task tended to be intervals that were overproduced (IRI > ISI) when they were used as ISIs in the constrained task. A multiple-oscillator model of timing developed by Church and Broadbent (1990) was used to simulate the two tasks. The nonlinearity in constrained tapping, termed the oscillator signature, and the bimodal distribution in unconstrained tapping were both exhibited by the model. The nature of the experimental results and the success of the simulation in capturing them both provide further support for a multiple-oscillator view of timing.
TL;DR: The diatom biostratigraphy of fossil diatoms contributes important chronologic, paleolimnologic, and paleoclimatic information from Lake Baikal in southeastern Siberia.
Abstract: The biostratigraphy of fossil diatoms contributes important chronologic, paleolimnologic, and paleoclimatic information from Lake Baikal in southeastern Siberia. Diatoms are the dominant and best preserved microfossils in the sediments, and distinctive assemblages and species provide inter-core correlations throughout the basin at millennial to centennial scales, in both high and low sedimentation-rate environments. Distributions of unique species, once dated by radiocarbon, allow diatoms to be used as dating tools for the Holocene history of the lake. Diatom, pollen, and organic geochemical records from site 305, at the foot of the Selenga Delta, provide a history of paleolimnologic and paleoclimatic changes from the late glacial (15 ka) through the Holocene. Before 14 ka diatoms were very rare, probably because excessive turbidity from glacial meltwater entering the lake impeded productivity. Between 14 and 12 ka, lake productivity increased, perhaps as strong winds promoted deep mixing and nutrient regeneration. Pollen evidence suggests a cold shrub — steppe landscape dominated the central Baikal depression at this time. As summer insolation increased, conifers replaced steppe taxa, but diatom productivity declined between 11 and 9 ka perhaps as a result of increased summer turbidity resulting from violent storm runoff entering the lake via short, steep drainages. After 8 ka, drier, but more continental climates prevailed, and the modern diatom flora of Lake Baikal came to prominence. On Academician Ridge, a site of slow sedimentation rates, Holocene diatom assemblages at the top of 10-m cores reappear at deeper levels suggesting that such cores record at least two previous interglacial (or interstadial?) periods. Nevertheless, distinctive species that developed prior to the last glacial period indicate that the dynamics of nutrient cycling in Baikal and the responsible regional climatic environments were not entirely analogous to Holocene conditions. During glacial periods, the deep basin sediments of Lake Baikal are dominated by rapidly deposited clastics entering from large rivers with possibly glaciated headwaters. On the sublacustrine Academician Ridge (depth = 300 m), however, detailed analysis of the diatom biostratigraphy indicates that diastems (hiatuses of minor duration) and (or) highly variable rates of accumulation complicate paleolimnologic and paleoclimatic reconstructions from these records.
TL;DR: In order to help clarify reliability and validity from the phenomenological perspective, Colaizzi, Giorgi, and Van Kaam 's methodologies are compared and contrasted regarding their stance on these issues.
Abstract: Reliability and validity are two areas where the criteria of logical empiricism appear to be imposed upon phenomenology as a research method. Cross-paradigmatic communication can result in difficulties because the same words may have different meanings. It cannot be assumed that reliability and validity have the same meaning in logical empiricism and phenomenology. Even among the three most frequently used phenomenological methods in nursing research, lack of consensus exists regarding the issues of reliability and validity. In order to help clarify reliability and validity from the phenomenological perspective, Colaizzi, Giorgi, and VanKaam's methodologies are compared and contrasted regarding their stance on these issues. Lincoln and Guba's four major criteria for rigor in qualitative inquiry, truth value, applicability, consistency, and neutrality may offer phenomenologists an appropriate alternative to logical positivists' terminology.
TL;DR: Gut content analyses of field-collected specimens and a mesocosm experiment indicated that large prey, with escape speeds slower than the marginal flow velocities around the bell margins of A. aurita, made up a substantial fraction of the daily ration when they were available and may be more important to nutrition than the more abundant copepods and microzooplankton.
Abstract: We describe feeding behavior of Aurelia aurita (Linnaeus) using gut content analyses of field-collected specimens and a mesocosm experiment. The field studies were conducted in Narragansett Bay, Rhode Island, USA from March to April 1988, and the mesocosm studies were done at the Marine Ecosystems Research Laboratory at the University of Rhode Island. Patterns of prey selection changed with medusa diameter. Smaller medusae (12 mm diameter) consumed mostly hydromedusan prey whereas larger medusae (up to 30 mm diameter) ingested greater numbers of copepod prey. While larger medusae did feed on copepods, their diet also contained more barnacle nauplii and hydromedusae than expected from the relative abundances of these prey types in plankton samples. A marginal flow mechanism of feeding by A. aurita provided an explanation for the patterns of prey selection we observed in medusae of different sizes and among widely divergent prey types. Our data indicated that large prey, with escape speeds slower than the marginal flow velocities around the bell margins of A. aurita, made up a substantial fraction of the daily ration when they were available. Such prey species may be more important to nutrition than the more abundant copepods and microzooplankton. Successful development of young medusae may depend upon an adequate supply of slowly escaping prey.