Showing papers by "San Francisco State University published in 2000"

Simple rules yield complex food webs

Abstract: Several of the most ambitious theories in ecology1,2,3,4,5,6,7,8,9,10,11,12,13,14 describe food webs that document the structure of strong and weak trophic links9 that is responsible for ecological dynamics among diverse assemblages of species4,11,12,13. Early mechanism-based theory asserted that food webs have little omnivory and several properties that are independent of species richness1,2,3,4,6. This theory was overturned by empirical studies that found food webs to be much more complex5,7,8,9,14,15,16,17,18, but these studies did not provide mechanistic explanations for the complexity9. Here we show that a remarkably simple model fills this scientific void by successfully predicting key structural properties of the most complex and comprehensive food webs in the primary literature. These properties include the fractions of species at top, intermediate and basal trophic levels, the means and variabilities of generality, vulnerability and food-chain length, and the degrees of cannibalism, omnivory, looping and trophic similarity. Using only two empirical parameters, species number and connectance, our ‘niche model’ extends the existing ‘cascade model’3,19 and improves its fit ten-fold by constraining species to consume a contiguous sequence of prey in a one-dimensional trophic niche20.

DIVERSIFICATION OF RAINFOREST FAUNAS: An Integrated Molecular Approach

Abstract: ▪ Abstract Understanding the evolutionary processes that generate and sustain diversity in tropical faunas has challenged biologists for over a century and should underpin conservation strategies. Molecular studies of diversity within species and relationships among species, when integrated with more traditional approaches of biogeography and paleoecology, have much to contribute to this challenge. Here we outline the current major hypotheses, develop predictions relevant to integrated molecular approaches, and evaluate the current evidence, focusing on central African, Australian, and South American systems. The available data are sparse relative to the scale of the questions. However, the following conclusions can be drawn: (a) in most cases, the divergence of extant sister taxa predates the Pleistocene; (b) areas with high habitat heterogeneity and recent climatic or geological instability appear to harbor more species of recent origin; (c) there is support for both allopatric and gradient models of di...

Opportunity Recognition: An Exploratory Investigation of a Component of the Entrepreneurial Process in the Context of the Health Care Industry

Abstract: In this study we build upon a conceptualization of part of the entrepreneurship process that is frequently labeled “entrepreneurial attitude orientation.” This study uses a contextually rich concep...

Individuals–area relationships: the relationship between animal population density and area

Abstract: We compiled studies that report data on the relationship between animal population density and patch or island area for 287 individual species and 21 faunas. We tested the assumption of the equilibrium theory of island biogeography that population densities are independent of area by performing a meta-analysis using the linear correlation coefficient,r, as a measure of the effect of area on population density. We fit meta-analyses that used a random-effects model to these data to test for the effects of taxa, habitat, latitude, spatial scale, and overall population density. We also fit meta-analyses that used a fixed- effect model to the same data to estimate the repeatability of measurements of the correlation between population density and area within species. Contrary to the equilibrium theory of island biogeography, our results indicate that, on average, animal population densities are positively correlated with area, which suggests that density compensation may be uncommon. This result was found for individual species, but not for faunas. We found taxonomic differences in the correlation between population density and area, with insects and birds having on average large or moderately large positive correlations, respectively, and mammals having correlations near zero. Observations within individual species showed considerable repeatability. The observed overall positive cor- relation between the population density of individual animal species and area is best ex- plained in the context of the resource concentration hypothesis. Our results imply that the regional abundance and persistence of animal populations may depend strongly on the presence and continued persistence of a few large patches of suitable habitat, rather than on a regional network of small and large habitat patches.

A New Test to Measure Emotion Recognition Ability: Matsumoto and Ekman's Japanese and Caucasian Brief Affect Recognition Test (JACBART)

Abstract: In this article, we report the development of a new test designed to measure individual differences in emotion recognition ability (ERA), five studies examining the reliability and validity of the scores produced using this test, and the first evidence for a correlation between ERA measured by a standardized test and personality. Utilizing Matsumoto and Ekman's (1988) Japanese and Caucasian Facial Expressions of Emotion (JACFEE) and Neutral Faces (JACNeuF), we call this measure the Japanese and Caucasian Brief Affect Recognition Test (JACBART). The JACBART improves on previous measures of ERA by (1) using expressions that have substantial validity and reliability data associated with them, (2) including posers of two visibly different races (3) balanced across seven universal emotions (4) with equal distribution of poser race and sex across emotions (5) in a format that eliminates afterimages associated with fast exposures. Scores derived using the JACBART are reliable, and three studies demonstrated a correlation between ERA and the personality constructs of Openness and Conscientiousness, while one study reports a correlation with Extraversion and Neuroticism.

Rapid and early export of Phaeocystis antarctica blooms in the Ross Sea, Antarctica

Abstract: The Southern Ocean is very important for the potential sequestration of carbon dioxide in the oceans1 and is expected to be vulnerable to changes in carbon export forced by anthropogenic climate warming2. Annual phytoplankton blooms in seasonal ice zones are highly productive and are thought to contribute significantly to pCO2 drawdown in the Southern Ocean. Diatoms are assumed to be the most important phytoplankton class with respect to export production in the Southern Ocean; however, the colonial prymnesiophyte Phaeocystis antarctica regularly forms huge blooms in seasonal ice zones and coastal Antarctic waters3. There is little evidence regarding the fate of carbon produced by P. antarctica in the Southern Ocean, although remineralization in the upper water column has been proposed to be the main pathway in polar waters4,5. Here we present evidence for early and rapid carbon export from P. antarctica blooms to deep water and sediments in the Ross Sea. Carbon sequestration from P. antarctica blooms may influence the carbon cycle in the Southern Ocean, especially if projected climatic changes lead to an alteration in the structure of the phytoplankton community6,7.

Predators, parasitoids and pathogens: species richness, trophic generality and body sizes in a natural food web

Abstract: Summary 1. A food web is presented which describes trophic interactions among the herbivores, parasitoids, predators and pathogens associated with broom, Cytisus scoparius (L.) Link. The data come from published work on the community at a single site. The web comprises a total of 154 taxa: one plant, 19 herbivores, 66 parasitoids, 60 predators, five omnivores and three pathogens. There are 370 trophic links between these taxa in the web. The taxa form 82 functionally distinct groups, called trophic species. 2. Predators consumed significantly more species than did parasitoids: a median of two prey species per species of predator (range = 1–9), compared to a median of one host species per species of parasitoid (range = 1–4). Significant differences in the number of species consumed were also found among the five predator groups: birds (median = 4), spiders (median = 5), Coleoptera (median = 1), Diptera (median = 2) and Hemiptera (median = 7). 3. Vulnerability, measured by numbers of consumer species, was significantly affected by the herbivores’ feeding styles: externally feeding herbivores were most vulnerable and the concealed herbivores were least vulnerable. Miners were vulnerable to the most parasitoid species and externally feeding herbivores were the most vulnerable to predators. 4. Resource species had a median vulnerability of 13 consumer species, a figure far higher than that in most published food webs. No significant relationship was found between species’ vulnerability to predators and vulnerability to parasitoids. However, there was a strong negative relationship between the percentage mortality due to predation and percentage mortality due to parasitism. 5. The broom food web contains nine orders of insects, a figure higher than previously recorded. The web also contains vertebrates, arachnids, bacteria and fungi. Most of the interactions between the orders were weak. Connectance was calculated for the complete web, the parasitoid sub-web and the predator sub-web. The connectance of the predator sub-web, a value of 0·0364, was more than an order of magnitude larger than the connectance of the entire web (0·0156) or the parasitoid sub-web (0·018). 6. The body lengths of 52 species in the food web were estimated from field guides or museum specimens. Larger predators consumed smaller prey in 93% of predator–prey interactions. Smaller parasitoids consumed larger hosts in 79% of parasitoid–host interactions. Parasitoids were significantly smaller than predators. 7. The 52 species were arranged in order of increasing body length along the columns and down the rows of a food web matrix. The predator sub-web was predominantly upper triangular with 8% of non-zero elements falling below the leading diagonal. The parasitoid sub-web was predominantly lower triangular with 21% non-zero elements falling above the leading diagonal. The entire web contains entries both above and below the main diagonal and thus violates a central assumption of the cascade model.

Brief Strategic Family Therapy: Twenty-Five Years of Interplay Among Theory, Research and Practice in Adolescent Behavior Problems and Drug Abuse

Abstract: This article describes a systematic program of research that focuses on Brief Strategic Family Therapy (BSFT) and the adaptations that were developed based on BSFT principles. The culture-specific origins of BSFT are reviewed, as well as its broader applications to the field of family therapy. Research is reviewed demonstrating that BSFT is a promising family-based approach to treating Hispanic youth behavior problems and drug abuse. Treatment innovations are described that address the combination of intergenerational and cultural differences that occur among youths and their Hispanic parents. Programmatic work is described that challenges basic principles of family therapy by expanding BSFT to a One Person modality and a strategic engagement procedure. Both of these novel approaches are intended to add tools to therapists' repertoire in working with difficult-to-engage families. A preview discussion of results is presented from a randomized clinical trial that is an application of an ecosystemic prevention version of BSFT. The implications of the work of the Center for Family Studies are discussed in the context of the broader service system. Ultimately, this article articulates a way of thinking about adolescent problem behavior, its social interactional determinants, and a range of theoretically consistent family-centered strategies that attempt to change social ecological processes that impact adolescent developmental trajectories.

Social Dominance Orientation and the Legitimization of Inequality Across Cultures

Abstract: The authors tested three hypotheses from social dominance theory in four cultures: (a) that individual differences in social dominance orientation (SDO), or the preference for group-based inequality, can be reliably measured in societies that are group-based hegemonies; (b) that SDO correlates positively with attitudes supporting hegemonic groups and correlates negatively with attitudes supporting oppressed groups; and (c) that men are higher on SDO than women. For the most part, the results confirmed the hypotheses. SDO scales were internally reliable and were administered in English, Chinese, and Hebrew. SDO scores correlated with sexism, measured in culturally appropriate ways, in every culture, and with ethnic prejudice and other attitudes concerning the local hegemony except in China. Men were higher on SDO than women in most samples. Findings are discussed in terms of ideological and psychological facilitators of group dominance.

A critical review of the critical period research

Abstract: Two decades of international research in applied linguistics provides a large number and variety of topics from which to choose for this special anniversary edition, but certainly one of the most significant among these choices is the critical period hypothesis (CPH). Few topics in applied linguistics have continued to captivate the interests of researchers and practitioners so intensively and for such a long period of time as the CPH. Indeed, one could easily go back to reviewing three, not two decades of sustained research and continuous interest in this topic (Lenneberg 1967, Scovel 1969). If number and diversity of publications is indicative, the CPH has engendered even more interest and controversy now than in any previous decade. Why is this so?

Measurement of fat mass using DEXA: a validation study in elderly adults.

Abstract: The accuracy of total body fat mass and leg fat mass measurements by fan-beam dual-energy X-ray absorptiometry (DEXA) was assessed in 60 healthy elderly subjects (aged 70–79 yr). Total fat and leg ...

Accountability and automation bias

Abstract: Although generally introduced to guard against human error, automated devices can fundamentally change how people approach their work, which in turn can lead to new and different kinds of error. The present study explored the extent to which errors of omission (failures to respond to system irregularities or events because automated devices fail to detect or indicate them) and commission (when people follow an automated directive despite contradictory information from other more reliable sources of information because they either fail to check or discount that information) can be reduced under conditions of social accountability. Results indicated that making participants accountable for either their overall performance or their decision accuracy led to lower rates of “automation bias”. Errors of omission proved to be the result of cognitive vigilance decrements, whereas errors of commission proved to be the result of a combination of a failure to take into account information and a belief in the superior judgement of automated aids.

Seed dispersal and movement patterns in two species of Ceratogymna hornbills in a West African tropical lowland forest.

Abstract: We studied two species of Ceratogymna hornbills, the black-casqued hornbill, C. atrata, and the white-thighed hornbill, C. cylindricus, in the tropical forests of Cameroon, to understand their movement patterns and evaluate their effectiveness as seed dispersers. To estimate hornbill contribution to a particular tree species' seed shadow we combined data from movements, determined by radio-tracking, with data from seed passage trials. For 13 individuals tracked over 12 months, home range varied between 925 and 4,472 ha, a much larger area than reported for other African avian frugivores. Seed passage times ranged from 51 to 765 min, with C. atrata showing longer passage times than C. cylindricus, and larger seeds having longer gut retention times than smaller seeds. Combining these data, we estimated that seed shadows were extensive for the eight tree species examined, with approximately 80% of seeds moved more than 500 m from the parent plant. Maximum estimated dispersal distances for larger seeds were 6,919 and 3,558 m for C. atrata and C. cylindricus, respectively. The extent of hornbill seed shadows suggests that their influence in determining forest structure will likely increase as other larger mammalian dispersers are exterminated.

Internet-Based Evaluation of Tourism Web Site Effectiveness: Methodological Issues and Survey Results

Abstract: There is growing reliance on the Internet and Web sites for promotion of tourism. Evaluation of Web site effectiveness is necessary because of the significant costs for setup, advertising, and maintenance. Research suggests there is a great need for evaluations to go beyond hits and page viewings. The objectives of this study were to develop and apply a low-cost, automated, Internet-based survey methodology to investigate effectiveness of a tourism promotional Web site. Both online and email surveys were used to gather data from visitors to a state Web site. Although responses were received from 833 persons, response rates were low. A check for nonresponse bias indicated that respondents were different from nonrespondents. Respondents primarily learned about the Web site through two sources and reported that the Web site significantly influenced their travel plans. However, study findings suggest that there are substantial methodological challenges in conducting Web-based surveys. Suggestions to improve e...

Genetic evidence for the effect of a postglacial population expansion on the phylogeography of a North American songbird

Abstract: Phylogeographical studies of Nearctic songbirds conducted to date have yielded unexpectedly low levels of genetic differentiation and weak phylogeographical structure in mitochondrial DNA lineages as compared with species studied in Neotropical areas. Factors leading to this pattern may include (i) gene flow, (ii) population expansions from bottlenecked populations, and (iii) selective sweeps. Here we provide evidence for the role played by Pleistocene postglacial population expansions on the phylogeography of MacGillivray's warbler (Oporornis tolmiei), a long-distance migratory bird. Samples from 12 breeding localities in the temperate USA were compared with those from two localities in north-eastern Mexico. The former showed evidence of a Late Pleistocene population expansion as indicated by low haplotype and nucleotide diversity, a star-like phylogeny of alleles, and a mismatch distribution indicating a sudden increase in effective population size. By contrast, the Mexican population showed high levels of genetic diversity and a mismatch distribution as expected for a population unaffected by sudden demographic change. Haplotypes from the two regions formed two distinct phylogroups which separated roughly one million years ago according to a conventional molecular clock for songbirds. This study provides support for the Pleistocene expansion hypothesis in MacGillivray's warbler and suggests that postglacial expansion of bottlenecked populations is responsible for the lack of variation and structure reported for most North American songbird species.

The magical age of 10.

Abstract: Developmental processes of "puberty" and their cultural contexts in understanding the emergence of sexual subjectivity, especially sexual attraction, prior to gonadarche are critically examined. In particular, we consider the hypothesis that "sexual attraction" follows the onset of adrenal puberty, termed adrenarche, precipitating the development of stable and memorable attraction toward others approximately by the age of 10. In a prior study, the authors suggested that adrenarche is a significant source of this developmental change in sexuality (McClintock, M., and Herdt, G., 1996). The inferential evidence from New Guinea is compared with recent studies from the United States, including clinical findings on "precocious puberty." We conclude with the question of whether the age of 10 is a human universal in the development of attraction and sexuality.

Heterogeneity of variance in clinical data.

Abstract: Traditional parametric (t, F) and nonparametric (Mann-Whitney-Wilcoxon U, Kruskal-Wallis H) statistics are sensitive to heterogeneity of variance (heteroscedasticity). Moreover, there are theoretical reasons to expect, and empirical results to document, the existence of heteroscedasticity in clinical data. Transformations to reduce heteroscedasticity are problematic. This article reviews the literature on robust methods that are available and that should be widely used to control rate of Type I error and maintain power. No one robust method is ideal for all situations, but such methods are superior to the traditional tests. Specific recommendations are made for application under various conditions of heteroscedasticity.

First Results from the Anglo-Australian Planet Search - A Brown Dwarf Candidate and a 51 Peg-like Planet

Abstract: We report results from the Anglo-Australian Planet Search -- a survey for planets around 200 solar-type stars in the southern hemisphere, which is being carried out on the 3.9m Anglo-Australian Telescope. Limiting Doppler precisions of 3m/s have been demonstrated from the first 2.5 years of operation, making this the highest precision planet search in the southern hemisphere. From these data we report results for two new sub-stellar detections. The first is a "51 Peg"-like planet around the star HD179949 with Msin i = 0.84 Mjup. Photometric study reveals this is not a transiting system. The second is a brown dwarf or very low-mass star companion to HD164427 in an eccentric orbit with Msin i = 46Mjup. Hipparcos data indicate this latter object is unlikely to have a mass greater than 0.18 Msol.

Nutrient regulation of phytoplankton productivity in Monterey Bay, California

Abstract: A series of nutrient enrichment grow-out experiments were conducted in Monterey Bay, California, to assess the relative importance of nutrient availability on growth rates and biomass accumulation of the natural phytoplankton assemblage. During a series of four cruises, enrichments with nitrogen (as nitrate and ammonium), silicate, and Guillard's “ f ” medium consistently demonstrated that the phytoplankton were nitrogen limited, and that the addition of nitrate provided the most potential for growth and biomass accumulation. Contrary to previous reports for Monterey Bay, silicate was not found to limit the accumulation of biomass in this diatom-dominated system, although there was evidence that silicate additions can modify the uptake rates of the biomass-limiting substrate (nitrogen). We conclude that silicate is a regulating, but not limiting, nutrient in this study site. Our results are consistent with both the “shift-up” and “detrital” explanations for changes in specific uptake rates. During upwelling periods (May, September) when the biomass was dominated by phytoplankton, a shift-up type physiological response was observed that was not dependent on the uptake normalization procedure (e.g. chlorophyll versus PN). During the winter months (March, November), characterized by deep mixing, low light, and higher detrital N levels, the apparent shift-up response could be attributed to a change in the PN : Chl ratios and alleviation of light limitation due to the stable light regime provided by the enclosures.

Modeling Intercategory and Generational Dynamics for A Growing Information Technology Industry

Abstract: Previous studies dealing with product growth have dealt only with substitution effects among successive generations of one product category and not with complementarity and competition provided by related product categories. Based on a broadened concept of the competitive information technology IT market, we develop a dynamic market growth model that is able to incorporate both interproduct category and technological substitution effects simultaneously. The market potential for each category or generation is treated as a variable rather than a constant parameter, which is typical of recently growing IT sectors such as wireless telecommunications. The model is calibrated, its plausibility discussed, and its face and predictive validity assessed using data on wireless telecommunications services from two Asian markets. Results show that the market potential and sales growth of one category or generation is significantly affected by others and by the overall structure of a geographic market. The model is shown to make relatively good predictions even when the data from recently introduced categories/generations are limited.

Phosphatidylinositol 3-kinase and mTOR mediate lipopolysaccharide-stimulated nitric oxide production in macrophages via interferon-beta.

Abstract: Bacterial lipopolysaccharide (LPS) elicits responses by macrophages that help the body repel infections. Recent evidence indicates that phosphatidylinositol 3-kinase (PI 3-kinase) may mediate some of these responses. Here, we show that exposing macrophages to LPS rapidly increased membrane-associated PI 3-kinase activity and also elevated p70 S6 kinase activity. Inhibitors of PI 3-kinase or the mammalian target of rapamycin (mTOR) fully blocked p70 S6 kinase activation, implying that this kinase is controlled by PI 3-kinase and mTOR. These inhibitors also substantially reduced LPS-induced nitric oxide (NO) production. This inhibition was, in part, attributable to impaired LPS-stimulated secretion of interferon-beta, an autocrine co-factor for NO production. However, the addition of exogenous interferon-beta did not fully restore NO production, indicating that the NO response was being inhibited by another mechanism as well. Together, these data suggest that PI 3-kinase, mTOR, and possibly p70 S6 kinase mediate LPS-induced NO production by regulating the secretion of interferon-beta and by a second undefined mechanism.

Management of Pacific Rockfish

Abstract: POLICY The American Fisheries Society (AFS) recognizes the need for conservative and robust management of Pacific rockfishes because of naturally low population growth, the overfished state of many of the stocks, and complex nature of the mixed-stock fisheries (60-plus species). The AFS recommends that catch information be collected on a species-specific basis, and that management targets also be established on a species-specific basis including species taken as bycatch. Such management will require accurate studies of discards at sea. Reduction in rockfish discards should be a management priority in all fisheries which capture significant numbers of rockfish. The AFS further recommends establishment of adequate fishery independent surveys to more accurately assess and monitor rockfish stocks. The AFS supports the establishment of systems of Marine Protected Areas to protect the habitat of Pacific rockfish and to promote recovery of stocks. Such areas should be established along with traditional management measures to control fishing mortality. Regardless of the management strategy used, substantial decreases in fishing mortality must be achieved soon to avoid stock collapses. The AFS encourages its members to become involved by providing technical information needed for protection of rockfish to international, federal, state, and provincial policy makers so decisions are made on a scientific, rather than emotional or political, basis.

Dynamics of piecewise isometries

Abstract: We begin a systematic study of Euclidean piecewise isometric dynamical systems (p.i.d.s.) with a particular focus on the interplay between geometry, symbolic dynamics, and the group of isometries associated with p.i.d.s. We investigate various aspects of the dynamical information contained in the coding: symbolic growth and the periodic behavior of codings and cells. This theoretical investigation is motivated by the many examples of piecewise isometric dynamical systems found recently in the literature. Piecewise isometric dynamical systems are direct generalizations of interval exchange transformations to non-invertible, higher dimensional maps.

Friendship in childhood and adulthood: lessons across the life span.

Abstract: Friendship occupies an important place in the growing body of literature in child development and gerontological research. As such, it may be useful for researchers from both fields to consider what can be learned from work carried out in each tradition. Therefore, we present a selected review of topics in friendship research across the life span. Through discussion of the value of friendship, the development of friendship, challenges to friendship, the gendered nature of friendship, and the connection between friends and family, points of commonality and contrast are identified. We conclude by presenting possible avenues for future investigation for researchers interested in friendship at any point in the life span.

The McCoy Female Sexuality Questionnaire

Abstract: The McCoy Female Sexuality Questionnaire (MFSQ) was developed from the questionnaire used in a longitudinal study of the menopausal transition and designed to measure aspects of female sexuality likely to be affected by changing sex hormone levels The original questionnaire was revised to insure that questions were easy to understand and that labels for the Likert scales described a continuum The revised MFSQ contains 19 questions, 18 items using 7-point Likert scales with labels at the center and endpoints and one item requesting a frequency of activity Seven studies involving both clinical and convenience samples and two with double blind randomized controlled trials used 7, 9, 10 or 17 MFSQ items and demonstrated acceptable reliability, internal consistency, apparent face and content validity as well as considerable evidence of construct validity Results showed selected MFSQ item ratings decreased as women progressed through the menopausal transition, varied positively with endogenous estradiol and androgen levels, were higher in postmenopausal women receiving hormone replacement therapy (HRT), and differentiated between different types of oral contraceptives and the presence or absence of ovaries Convergent validity was demonstrated for change in 9-item MFSQ score with change in psychological general well-being (PGWB) score and the Women's Health Questionnaire (WHQ) sex life subscale

Quantification, Qualification and Context A Reply to Stanley and Szabó

Abstract: Rejetant l'approche semantique de la restriction du domaine de quantification defendue par J. Stanley et Z. G. Szabo, l'A. definit le discours vague en termes de non-litteralite de la phrase et adopte la conception pragmatique de la quantification implicite. Examinant le role de la qualification et du contexte, l'A. avance l'hypothese de domaines variables, en reponse a la critique qui lui adressent Stanley et Szabo dans l'article precedent.

Biomass and productivity in Monterey Bay, California: contribution of the large phytoplankton

Abstract: The contribution of large phytoplankton to the standing stock and productivity of the eastern-boundary ecosystem of Monterey Bay, California, was evaluated during 1992 and 1993, using size fractionation. Eight cruises sampled the variability of the bay both spatially (within the upwelling plume and offshore) and temporally (during upwelling and non-upwelling seasons, El Nino and non-El Nino years). The larger cell sized (>5 μm) autotrophs contributed significantly to chlorophyll, particulate nitrogen, and new and primary productivity in most cruises. This was especially noticeable above a threshold nutrient concentration of 10–12 μM nitrate. Pooling the entire dataset, there were good linear relationships between biomass and productivity parameters measured using GF/F and 5 μm filters. The contribution of the >5 μm size fraction was greatest at higher biomass concentrations and productivity rates, supporting the idea that to reach maximal values, large cells are required. There were linear trends with Chl : PON ratio of close to 1, and 14 C : 15 NO 3 uptake ratio of about 10 in both total and >5 μm size fractions. These large cells are major contributors to carbon and nitrogen productivity in Monterey Bay.

Entering Preschool: Family and Professional Experiences in This Transition Process:

Abstract: Important changes in services occur for children with disabilities at age 3. A qualitative cross-site approach was used to investigate the experiences of families of these children and their service providers as they made the transition from Part C to Part B programs. Issues investigated were families' and professionals' experiences and expectations for the transition process, and the process of decision-making related to service selection. A sample of 22 families was followed as they entered, participated in, and exited the transition process. Results indicated that families and professionals experienced this transition as an event, not as a process. The shift in service delivery models from infant-toddler services to preschool services was often problematic, and information exchange and communication was crucial to family involvement and decision making. In general, families were given limited choices with respect to preschool programs; Only few programs offered inclusive service models. Families' and p...