University System of Georgia

This article addresses Rönkkö and Evermann’s criticisms of the partial least squares (PLS) approach to structural equation modeling. We contend that the alleged shortcomings of PLS are not due to problems with the technique, but instead to three problems with Rönkkö and Evermann’s study: (a) the adherence to the common factor model, (b) a very limited simulation designs, and (c) overstretched generalizations of their findings. Whereas Rönkkö and Evermann claim to be dispelling myths about PLS, they have in reality created new myths that we, in turn, debunk. By examining their claims, our article contributes to reestablishing a constructive discussion of the PLS method and its properties. We show that PLS does offer advantages for exploratory research and that it is a viable estimator for composite factor models. This can pose an interesting alternative if the common factor model does not hold. Therefore, we can conclude that PLS should continue to be used as an important statistical tool for management and organizational research, as well as other social science disciplines.

The sudden and perhaps unexpected appearance of populist parties in the 1990s shows no sign of immediately vanishing. The lion’s share of the research on populism has focused on defining populism, on the causes for its rise and continued success, and more recently on its influence on government and on public policy. Less research has, however, been conducted on measuring populist attitudes among voters. In this article, we seek to fill this gap by measuring populist attitudes and to investigate whether these attitudes can be linked with party preferences. We distinguish three political attitudes: (1) populist attitudes, (2) pluralist attitudes, and (3) elitist attitudes. We devise a measurement of these attitudes and explore their validity by way of using a principal component analysis on a representative Dutch data set ( N = 600). We indeed find three statistically separate scales of political attitudes. We further validated the scales by testing whether they are linked to party preferences and find that voters who score high on the populist scale have a significantly higher preference for the Dutch populist parties, the Party for Freedom, and the Socialist Party.

BACKGROUND: HHT is an autosomal dominant disease with an estimated prevalence of at least 1/5000 which can frequently be complicated by the presence of clinically significant arteriovenous malformations in the brain, lung, gastrointestinal tract and liver. HHT is under-diagnosed and families may be unaware of the available screening and treatment, leading to unnecessary stroke and life-threatening hemorrhage in children and adults. OBJECTIVE: The goal of this international HHT guidelines process was to develop evidence-informed consensus guidelines regarding the diagnosis of HHT and the prevention of HHT-related complications and treatment of symptomatic disease. METHODS: The overall guidelines process was developed using the AGREE framework, using a systematic search strategy and literature retrieval with incorporation of expert evidence in a structured consensus process where published literature was lacking. The Guidelines Working Group included experts (clinical and genetic) from eleven countries, in all aspects of HHT, guidelines methodologists, health care workers, health care administrators, HHT clinic staff, medical trainees, patient advocacy representatives and patients with HHT. The Working Group determined clinically relevant questions during the pre-conference process. The literature search was conducted using the OVID MEDLINE database, from 1966 to October 2006. The Working Group subsequently convened at the Guidelines Conference to partake in a structured consensus process using the evidence tables generated from the systematic searches. RESULTS: The outcome of the conference was the generation of 33 recommendations for the diagnosis and management of HHT, with at least 80% agreement amongst the expert panel for 30 of the 33 recommendations.

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 307:273-306 (2006) - doi:10.3354/meps307273 Lipid storage in marine zooplankton Richard F. Lee1,*, Wilhelm Hagen2, Gerhard Kattner3 1Skidaway Institute of Oceanography, 10 Ocean Science Circle, Savannah, Georgia 31406, USA2Marine Zoologie, Universität Bremen (NW2), Postfach 330440, 28334 Bremen, Germany3Alfred-Wegener-Institut für Polar- und Meeresforschung, Postfach 120161, 27515 Bremerhaven, Germany *Email: dick@skio.peachnet.edu ABSTRACT: Zooplankton storage lipids play an important role during reproduction, food scarcity, ontogeny and diapause, as shown by studies in various oceanic regions. While triacylglycerols, the primary storage lipid of terrestrial animals, are found in almost all zooplankton species, wax esters are the dominant storage lipid in many deep-living and polar zooplankton taxa. Phospholipids and diacylglycerol ethers are the unique storage lipids used by polar euphausiids and pteropods, respectively. In zooplankton with large stores of wax esters, triacylglycerols are more rapidly turned over and used for short-term energy needs, while wax esters serve as long-term energy deposits. Zooplankton groups found in polar, westerlies, upwelling and coastal biomes are characterized by accumulation of large lipid stores. In contrast, zooplankton from the trades/tropical biomes is mainly composed of omnivorous species with only small lipid reserves. Diapausing copepods, which enter deep water after feeding on phytoplankton during spring/summer blooms or at the end of upwelling periods, are characterized by large oil sacs filled with wax esters. The thermal expansion and compressibility of wax esters may allow diapausing copepods and other deep-water zooplankton to be neutrally buoyant in cold deep waters, and they can thus avoid spending energy to remain at these depths. Lipid droplets are often noted in zooplankton ovaries, and a portion of these droplets can be transferred to developing oocytes. In addition to lipid droplets, zooplankton eggs have yolks with lipovitellin, a lipoprotein with approximately equal amounts of protein and lipid. The lipovitellin lipid is predominantly phosphatidylcholine, so during reproduction females must convert a portion of their storage lipid into this phospholipid. Developing embryos use their lipovitellin and lipid droplets for energy and materials until feeding begins. The various functions storage lipids serve during the different life history stages of zooplankton are very complex and still not fully understood and hence offer a multitude of fascinating research perspectives. KEY WORDS: Zooplankton · Lipids · Wax esters · Triacylglycerols · Diapause · Reproduction · Ontogeny · Biomes Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 307. Online publication date: January 24, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research.

This research asks whether codes of ethics affect computer abuse judgments and intentions of information systems (IS) employees. Codes of ethics examined include both company codes of ethics and those written specifically to deal with IS issues. In addition, since the intent of codes of ethics is to clarify responsibility and deter unethical behavior, both the psychological trait of responsibility denial and its moderating effect on codes was studied. While company codes did not affect the computer abuse judgments and intentions of all IS personnel, they did affect those IS personnel who tend to deny responsibility, thus suggesting that company codes may clarify responsibility and reduce rationalizations for some people. Unlike company codes, IS-specific codes of ethics had a direct effect on computer sabotage judgments and intentions, but had no differential effect on those high in responsibility denial. Finally, responsibility denial was directly related to all computer abuse judgments and intentions studied. Overall, codes had little effect on computer abuse judgments and intentions relative to the psychological trait of responsibility denial.

Historical streamflow and concentration data were used in regression models to estimate the annual flux of nitrogen (N) to the Gulf of Mexico and to determine where the nitrogen originates within the Mississippi Basin. Results show that for 1980-1996 the mean annual total N flux to the Gulf of Mexico was 1,568,000 t yr-1. The flux was about 61% nitrate N, 37% organic N, and 2% ammonium N. The flux of nitrate N to the Gulf has approximately tripled in the last 30 years with most of the increase occurring between 1970 and 1983. The mean annual N flux has changed little since the early 1980s, but large year-to-year variations in N flux occur because of variations in precipitation. During wet years the N flux can increase by 50% or more due to flushing of nitrate N that has accumulated in the soils and unsaturated zones in the basin. The principal source areas of N are basins in southern Minnesota, Iowa, Illinois, Indiana, and Ohio that drain agricultural land. Basins in this region yield 1500 to more than 3100 kg N km-2 yr-1 to streams, several times the N yield of basins outside this region.

In an effort to clarify the relationship between the experience of sexual assault and physical health, rape victims and a matched comparison group were repeatedly assessed for somatic symptoms, psychological distress, health care use, and self-rated health perceptions during the year immediately after the assault. Women who experienced sexual assault reported more somatic complaints, poorer perceptions of physical health, greater psychological distress, and increased use of medical services. However, victims did not show a significantly higher use of mental health services and continued to seek medical attention at the end of the year after the assault, when health perceptions and somatic symptoms were no longer significantly elevated. The use of mental health services and social support as moderating variables are examined, and implications for the medical and psychological treatment of sexual assault victims are discussed.

This article describes how farmers of Burkina Faso predict seasonal rainfall and examines how their forecasts relate to those produced by meteorological science. Farmers' forecasting knowledge encompasses shared and selective repertoires. Most farmers formulate expectations from observation of natural phenomena. Cultural and ritual spiritualists also predict rainfall from divination, visions, and dreams. Rather than positing local and scientific knowledge as self-exclusive, our research shows that farmers operate in multiple cognitive frameworks. Moreover, they are interested in receiving scientific information because they perceive local forecasts as becoming less reliable as a result of increasing climate variability. Some aspects of local forecasting knowledge, such as those stressing the relationship between temperatures, wind, and rainfall, can help explain meteorology-based forecasts. But significant discordance remains between scientific and local forecasts. The former predict total rainfall quantity at a regional scale, whereas the latter stress rainfall duration and distribution and are more attuned to crop-weather interactions. Local systems of thought stress the relationship between knowledge and social responsibility. This emphasizes the need for scientists to integrate information dissemination projects with efforts to improve farmers' capacity to respond to forecasts and to cope with suboptimal climate impacts.

BACKGROUND: For more than three decades, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) has provided a framework to quantify health loss due to diseases, injuries, and associated risk factors. This paper presents GBD 2023 findings on disease and injury burden and risk-attributable health loss, offering a global audit of the state of world health to inform public health priorities. This work captures the evolving landscape of health metrics across age groups, sexes, and locations, while reflecting on the remaining post-COVID-19 challenges to achieving our collective global health ambitions. METHODS: The GBD 2023 combined analysis estimated years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs) for 375 diseases and injuries, and risk-attributable burden associated with 88 modifiable risk factors. Of the more than 310 000 total data sources used for all GBD 2023 (about 30% of which were new to this estimation round), more than 120 000 sources were used for estimation of disease and injury burden and 59 000 for risk factor estimation, and included vital registration systems, surveys, disease registries, and published scientific literature. Data were analysed using previously established modelling approaches, such as disease modelling meta-regression version 2.1 (DisMod-MR 2.1) and comparative risk assessment methods. Diseases and injuries were categorised into four levels on the basis of the established GBD cause hierarchy, as were risk factors using the GBD risk hierarchy. Estimates stratified by age, sex, location, and year from 1990 to 2023 were focused on disease-specific time trends over the 2010-23 period and presented as counts (to three significant figures) and age-standardised rates per 100 000 person-years (to one decimal place). For each measure, 95% uncertainty intervals [UIs] were calculated with the 2·5th and 97·5th percentile ordered values from a 250-draw distribution. FINDINGS: Total numbers of global DALYs grew 6·1% (95% UI 4·0-8·1), from 2·64 billion (2·46-2·86) in 2010 to 2·80 billion (2·57-3·08) in 2023, but age-standardised DALY rates, which account for population growth and ageing, decreased by 12·6% (11·0-14·1), revealing large long-term health improvements. Non-communicable diseases (NCDs) contributed 1·45 billion (1·31-1·61) global DALYs in 2010, increasing to 1·80 billion (1·63-2·03) in 2023, alongside a concurrent 4·1% (1·9-6·3) reduction in age-standardised rates. Based on DALY counts, the leading level 3 NCDs in 2023 were ischaemic heart disease (193 million [176-209] DALYs), stroke (157 million [141-172]), and diabetes (90·2 million [75·2-107]), with the largest increases in age-standardised rates since 2010 occurring for anxiety disorders (62·8% [34·0-107·5]), depressive disorders (26·3% [11·6-42·9]), and diabetes (14·9% [7·5-25·6]). Remarkable health gains were made for communicable, maternal, neonatal, and nutritional (CMNN) diseases, with DALYs falling from 874 million (837-917) in 2010 to 681 million (642-736) in 2023, and a 25·8% (22·6-28·7) reduction in age-standardised DALY rates. During the COVID-19 pandemic, DALYs due to CMNN diseases rose but returned to pre-pandemic levels by 2023. From 2010 to 2023, decreases in age-standardised rates for CMNN diseases were led by rate decreases of 49·1% (32·7-61·0) for diarrhoeal diseases, 42·9% (38·0-48·0) for HIV/AIDS, and 42·2% (23·6-56·6) for tuberculosis. Neonatal disorders and lower respiratory infections remained the leading level 3 CMNN causes globally in 2023, although both showed notable rate decreases from 2010, declining by 16·5% (10·6-22·0) and 24·8% (7·4-36·7), respectively. Injury-related age-standardised DALY rates decreased by 15·6% (10·7-19·8) over the same period. Differences in burden due to NCDs, CMNN diseases, and injuries persisted across age, sex, time, and location. Based on our risk analysis, nearly 50% (1·27 billion [1·18-1·38]) of the roughly 2·80 billion total global DALYs in 2023 were attributable to the 88 risk factors analysed in GBD. Globally, the five level 3 risk factors contributing the highest proportion of risk-attributable DALYs were high systolic blood pressure (SBP), particulate matter pollution, high fasting plasma glucose (FPG), smoking, and low birthweight and short gestation-with high SBP accounting for 8·4% (6·9-10·0) of total DALYs. Of the three overarching level 1 GBD risk factor categories-behavioural, metabolic, and environmental and occupational-risk-attributable DALYs rose between 2010 and 2023 only for metabolic risks, increasing by 30·7% (24·8-37·3); however, age-standardised DALY rates attributable to metabolic risks decreased by 6·7% (2·0-11·0) over the same period. For all but three of the 25 leading level 3 risk factors, age-standardised rates dropped between 2010 and 2023-eg, declining by 54·4% (38·7-65·3) for unsafe sanitation, 50·5% (33·3-63·1) for unsafe water source, and 45·2% (25·6-72·0) for no access to handwashing facility, and by 44·9% (37·3-53·5) for child growth failure. The three leading level 3 risk factors for which age-standardised attributable DALY rates rose were high BMI (10·5% [0·1 to 20·9]), drug use (8·4% [2·6 to 15·3]), and high FPG (6·2% [-2·7 to 15·6]; non-significant). INTERPRETATION: Our findings underscore the complex and dynamic nature of global health challenges. Since 2010, there have been large decreases in burden due to CMNN diseases and many environmental and behavioural risk factors, juxtaposed with sizeable increases in DALYs attributable to metabolic risk factors and NCDs in growing and ageing populations. This long-observed consequence of the global epidemiological transition was only temporarily interrupted by the COVID-19 pandemic. The substantially decreasing CMNN disease burden, despite the 2008 global financial crisis and pandemic-related disruptions, is one of the greatest collective public health successes known. However, these achievements are at risk of being reversed due to major cuts to development assistance for health globally, the effects of which will hit low-income countries with high burden the hardest. Without sustained investment in evidence-based interventions and policies, progress could stall or reverse, leading to widespread human costs and geopolitical instability. Moreover, the rising NCD burden necessitates intensified efforts to mitigate exposure to leading risk factors-eg, air pollution, smoking, and metabolic risks, such as high SBP, BMI, and FPG-including policies that promote food security, healthier diets, physical activity, and equitable and expanded access to potential treatments, such as GLP-1 receptor agonists. Decisive, coordinated action is needed to address long-standing yet growing health challenges, including depressive and anxiety disorders. Yet this can be only part of the solution. Our response to the NCD syndemic-the complex interaction of multiple health risks, social determinants, and systemic challenges-will define the future landscape of global health. To ensure human wellbeing, economic stability, and social equity, global action to sustain and advance health gains must prioritise reducing disparities by addressing socioeconomic and demographic determinants, ensuring equitable health-care access, tackling malnutrition, strengthening health systems, and improving vaccination coverage. We live in times of great opportunity. FUNDING: Gates Foundation and Bloomberg Philanthropies.

This paper analyzes the responses enacted by families of the Central Plateau in Burkina Faso during the year that followed a severe drought in 1997. We illustrate the agro-ecological and socio-economic contexts that shape livelihood options and constraints in an area characterized by high levels of climatic risk and low natural resource endowment. A description of farmers' perceptions and official accounts identifies key criteria whereby farmers formulate evaluations and predictions of a season. We document how food procurement and management practices are shaped by household resource access profiles and livelihood portfolios. Livelihood diversification, encompassing migration, non-farm work and social support networks, in addition to livestock production, is shown to be a critical dimension of adaptation. Livelihood and production adjustments entail costs and risks for most, but also gains for those who have the resources needed to take advantage of distress sales and high prices of agricultural commodities. Household livelihood and risk management increasingly hinge on efforts by household members who traditionally have had marginal access to resources, especially women. The research points to the need for closer integration of drought preparedness efforts, farmers' understanding of climate-crop interactions and interventions that bolster the capacity of resource-limited households to respond. Affordable grain, locally adapted seed varieties, labor saving technology and flexible credit are among the most needed inputs.

Abstract Despite the challenged contention that consumers serve more onto larger dinnerware, it remains unclear what would cause this and who might be most at risk. The results of five studies suggest that the neglected Delboeuf illusion may explain how the size of dinnerware creates two opposing biases that lead people to overserve on larger plates and bowls and underserve on smaller ones. A countercyclical sinus-shaped relationship is shown to exist between these serving biases and the relative gap between the edge of the food and the edge of the dinnerware. Although these serving biases are difficult to eliminate with attention and education, changing the color of one’s dinnerware or tablecloth may help attenuate them. By showing that the Delboeuf illusion offers a mechanistic explanation for how dinnerware size can bias serving and intake, we open new theoretical opportunities for linking illusions to eating behavior and suggest how simple changes in design can improve consumer welfare.

Significance Plant cells are surrounded by an extracellular matrix known as the cell wall. We have analyzed the contribution of the Arabidopsis cell wall to disease resistance to pathogens with different parasitic styles. Here, we demonstrate that plant cell walls are determinants of immune responses since modification of their composition in a set of Arabidopsis cell wall mutants has an impact on their disease resistance and fitness phenotypes. In these genotypes, we identified specific correlations between the amounts of specific wall carbohydrate epitopes and disease resistance/fitness phenotypes through mathematical analyses. These data support the relevant and specific function of plant cell wall composition in plant immune responses and provide the basis for using wall traits in crop breeding programs.

This study evaluated the effect of 2% chlorhexidine digluconate (CHX) used as a therapeutic primer on the long-term bond strengths of two etch-and-rinse adhesives to normal (ND) and caries-affected (CAD) dentin. Forty extracted human molars with coronal carious lesions, surrounded by normal dentin, were selected for this study. The flat surfaces of two types of dentin (ND and CAD) were prepared with a water-cooled high-speed diamond disc, then acid-etched, rinsed and air-dried. In the control groups, the dentin was re-hydrated with distilled water, blot-dried and bonded with a three-step (Scotchbond Multi-Purpose-MP) or two-step (Single Bond 2-SB) etch-and-rinse adhesive. In the experimental groups, the dentin was rehydrated with 2% CHX (60 seconds), blot-dried and bonded with the same adhesives. Resin composite build-ups were made. The specimens were prepared for microtensile bond testing in accordance with the non-trimming technique, then tested either immediately or after six-months storage in artificial saliva. The data were analyzed by ANOVA/Bonferroni tests (alpha = 0.05). CHX did not affect the immediate bond strength to ND or CAD (p > 0.05). CHX treatment significantly lowered the loss of bond strength after six months as seen in the control bonds for ND (p < 0.05), but it did not alter the bond strength of CAD (p > 0.05). The application of MP on CHX-treated ND or CAD produced bonds that did not change over six months of storage.

This review compares rates of oxygen uptake and intrinsic growth of very small invertebrate species near 20 "C with those of larger invertebrate and unicellular animals by means of the allometric relation (rate a Mb where M = mass). Respiration rates of small species of major invertebrate taxa are lower than those extrapolated for larger invertebrates but generally higher than those for protozoans of the same mass. Mass-specific rates of small metazoans and protozoans are lowered accordingly; therefore, their total food and oxygen consumption is likely to be small relative to that of large metazoans in average pelagic and benthic communities where most of the biomass is in large animals. The exponent b for each of the major taxa treated here tends to be near 0.75 rather than close to unity. Thus, the respiration of these taxa is about as mass dependent as that of large animals. Metabolic reduction is set in relation to small adult size as such, and previous inferences about the phylogeny of metazoan metabolism do not seem warranted any more. Intrinsic growth rates of benthic rotifers and marine free-living nematodes are not only lower than those extrapolated for larger invertebrates but fall below those for protozoans of the same mass. Among benthic harpacticoid copepods, a slight reduction relative to mass-scaled large invertebrates is indicated. Pelagic freshwater rotifers do not exhibit this reduction. Intrinsic growth rates of pelagic freshwater cladocerans are independent of adult mass and not clearly higher than those of the few pelagic copepods studied. Future research into the physiological reasons for mass dependence of metabolism and growth should focus on unicellular or small multicellular species because of their short generation times O Inter-Research/Printed in F. R. Germany

The mechanisms underpinning forest biodiversity-ecosystem function relationships remain unresolved. Yet, in heterogeneous forests, ecosystem function of different strata could be associated with traits or evolutionary relationships differently. Here, we integrate phylogenies and traits to evaluate the effects of elevational diversity on above-ground biomass across forest strata and spatial scales. Community-weighted means of height and leaf phosphorous concentration and functional diversity in specific leaf area exhibited positive correlations with tree biomass, suggesting that both positive selection effects and complementarity occur. However, high shrub biomass is associated with greater dissimilarity in seed mass and multidimensional trait space, while species richness or phylogenetic diversity is the most important predictor for herbaceous biomass, indicating that species complementarity is especially important for understory function. The strength of diversity-biomass relationships increases at larger spatial scales. We conclude that strata- and scale- dependent assessments of community structure and function are needed to fully understand how biodiversity influences ecosystem function.

BACKGROUND AND OBJECTIVES: The extent to which racial and socioeconomic disparities in access to kidney transplantation are related to not being assessed for transplant suitability before or shortly after the time of initiation of dialysis is not known. The aims of this study were to determine whether there were disparities based on race, ethnicity, or type of insurance in delayed assessment for transplantation and whether delayed assessment was associated with lower likelihood of waitlisting and kidney transplantation. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This retrospective cohort study used data from the US Renal Data System and included 426,489 adult patients beginning dialysis in the United States between January 1, 2005 and September 30, 2009 without prior kidney transplant. RESULTS: Overall, 12.5% of patients had reportedly not been assessed for transplantation. Patients without private insurance were more likely to be reported as not assessed (multivariable adjusted odds ratio=1.33, 95% confidence interval=1.28-1.40 for Medicaid), with a pronounced racial disparity but no ethnic disparity among patients aged 18 to <35 years (odds ratio=1.27, 95% confidence interval=1.13-1.43; P<0.001 for interaction with age). Not being assessed for transplant around the time of dialysis initiation was associated with lower likelihood of waitlisting in multivariable analysis (hazard ratio=0.59, 95% confidence interval=0.57-0.62 in the first year) and transplantation (hazard ratio=0.46, 95% confidence interval=0.41-0.51 in the first year), especially within the first 2 years. CONCLUSIONS: Racial and insurance-related disparities in transplant assessment potentially delay transplantation, particularly among younger patients.

Iowa Tests of Basic Skills (ITBS) mathematics scores of eighth graders who had received music instruction were compared according to whether the students were given private lessons. Comparisons also were made between students whose lessons were on the keyboard versus other music lessons. Analyses indicated that students who had private lessons for two or more years performed significantly better on the composite mathematics portion of the ITBS than did students who did not have private lessons. In addition, students who received lessons on the keyboard had significantly higher ITBS mathematics scores than did students whose lessons did not involve the keyboard. These results are discussed in relation to previous research on music training and mathematics achievement.

The fish assemblage using shallow nursery habitats in the Ogeechee River-Ossabaw Sound salt-marsh estuary, Georgia, was investigated during the winter and spring of two successive years. High river discharges during these periods produced fully freshwater conditions (all tidal stages and amplitudes) in the upper portion of the study area for up to 4 months. Abundances of Atlantic croaker Micropogonias undulatus, southern flounder Paralichthys lethostigma, silver perch Bairdiella chrysoura, and hogchoker Trinectes maculatus recruits were highest in the upper estuary. Spots Leiostomus xanthurus were more evenly distributed, but continued to use upper-estuary nursery areas during periods of high river discharge. Although the recruitment of several species likely was inhibited during discharge peaks, only striped mullet Mugil cephalus avoided freshwater conditions. Spots, southern flounder, Atlantic menhaden, and silver perch utilized shallow nursery areas on a size-specific basis. Recruitment and utilization patterns of fishes spawned in deeper areas generally were maintained throughout prolonged periods (up to 100 days) of freshwater conditions. The precise function of upper-estuary nursery areas is governed by the timing and magnitude of discharge events, but remains essentially intact through the seasonal encroachment of fresh water. Received June 9, 1983 Accepted May 15, 1984

Four research studies of students and faculty engaged in fully online undergraduate courses are analyzed to generate best practices for teaching and learning online. These studies investigated the relationship of student background variables and online behaviors to student persistence and achievement in the online environment. Over 500 students enrolled in lower division, undergraduate courses offered online were included in the analyses. The courses were designed by faculty and instructional design experts and met standards of quality course design established by the offering colleges and universities. By combining the results of the study, guidelines for advising students and faculty for success in the online environment emerged.

Numerous studies have examined “whether” and “why” policies diffuse, or the reasons for the adoption in a given government of a policy that exists in another government. This study explored the “how” of policy diffusion by focusing on college completion policies, especially performance funding. In particular, we examined the roles that intermediaries play in state-level college completion policy diffusion. Data are from 3 states and include observations of policy events, documents, and interviews with 56 participants, including state policy actors and intermediary representatives. This analysis, grounded in conceptual models of policy diffusion, revealed that diffusion occurs at various stages of the policy process, not just adoption. The study also demonstrated the coercive roles that intermediaries can play in promoting policies and revealed how intermediaries facilitate, and sometimes limit, policy learning, which is one of the primary mechanisms by which policies diffuse. By focusing on an underexplored conceptual model of policy diffusion, the national interaction model, this analysis shed light on the role played by intermediaries in state-level college completion policymaking.