Eutrophication-induced phosphorus limitation in the Mississippi River plume: Evidence from fast repetition rate fluorometry

We assessed nutrient limitation in the Mississippi River plurne and Louisiana continental shelf during the summer of 2002 (04-08 July). We measured nutrient concentrations, alkaline phosphatase (AP) activities, chlorophyll a (Chl a) concentrations, and four fast repetition rate fluorescence (FRRF) parameters: the maximum quantum yield of photochemistry in photosystem II (PSII), F-v:F-m; the functional absorption cross section for PSII, sigma(psII); the time for photosynthetic electron transport on the acceptor side of PSII, tau(Qa); and the connectivity factor, p, in 24-h-long nutrient addition bioassays near the Mississippi River delta. Low phosphorus (P) concentrations, elevated inorganic nitrogen-to-phosphorus ratios, high AP activities, and Chl a increases in response to P additions in the bioassays all indicated phosphorus limitation that was confirmed by the response of FRRF parameters. This is the first study to use FRRF to confirm results from basic oceanographic methods to demonstrate phosphorus limitation in a marine setting. F-v:F-m and p responded positively to phosphorus addition, while sigma(psII) and tau(Qa) decreased in the same treatments. When nitrate alone was added, none of the measured parameters differed significantly from the control. We therefore suggest that FRRF can be used to rapidly detect phosphorus limitation in marine ecosystems

Microbes and the marine phosphorus cycle

Author Posting. © Oceanography Society, 2007. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 20, 2 (2007): 110-116.Phosphorus (P) is fundamental to life, and years of study in marine systems have built a broad understanding of the marine P cycle. Various aspects of marine P biogeochemistry have been reviewed previously (Benitez-Nelson, 2000; Paytan and McLaughlin, 2007). Here, we focus on recent advances in our understanding of marine P and the interactions between microbes and the P cycle. These advances come from a variety of disciplines, but generally highlight three main themes: (1) ocean microbes are adapted for surviving in a variable P environment, (2) the dissolved organic phosphorus (DOP) pool likely plays a critical role in driving growth, metabolism, and community composition of ocean microorganisms, and (3) P is very rapidly cycled, which highlights its importance in marine systems

Effects of a Tailored Follow-Up Intervention on Health Behaviors, Beliefs, and Attitudes

Background: The high rates of relapse that tend to occur after short-term behavioral interventions indicate the need for maintenance programs that promote long-term adherence to new behavior patterns. Computer-tailored health messages that are mailed to participants or given in brief telephone calls offer an innovative and time-efficient alternative to ongoing face-to-face contact with healthcare providers. Methods: Following a 1-year behavior change program, 22 North Carolina health departments were randomly assigned to a follow-up intervention or control condition. Data were collected from 1999 to 2001 by telephone-administered surveys at preintervention and postintervention for 511 low-income, midlife adult women enrolled in the Well-Integrated Screening and Evaluation for Women Across the Nation (WISEWOMAN) program at local North Carolina health departments. During the year after the behavior change program, intervention participants were mailed six sets of computer-tailored health messages and received two computer-tailored telephone counseling sessions. Main outcomes of dietary and physical activity behaviors, beliefs, and attitudes were measured. Results: Intervention participants were more likely to move forward into more advanced stages of physical activity change (p = 0.02); control participants were more likely to increase their level of dietary social support at follow-up (p = 0.05). Both groups maintained low levels of reported saturated fat and cholesterol intake at follow-up. No changes were seen in physical activity in either group. Conclusions: Mailed computer-tailored health messages and telephone counseling calls favorably modified forward physical activity stage movement but did not appreciably affect any other psychosocial or behavioral outcomes

Association Between Physical Activity and Proximity to Physical Activity Resources Among Low-Income, Midlife Women

INTRODUCTION: The association between levels of physical activity and perceived and objectively measured proximity to physical activity resources is unclear. Clarification is important so that future programs can intervene upon the measure with the greatest association. We examined correlations between perceived and objectively measured proximity to physical activity resources and then examined associations between both measures of proximity and objectively measured physical activity. METHODS: Participants (n = 199) were underinsured women from three counties in southeastern North Carolina. Perceived proximity to physical activity resources (e.g., parks, gyms, schools) was measured using surveys. Objectively measured proximity included geographic information systems road network distance to the closest resource and existence of resources within 1- and 2-mile buffers surrounding participants' homes. To examine the association between proximity to resources and activity, the dependent variable in multiple linear regression models was the natural logarithm of accelerometer-measured moderate to vigorous physical activity in minutes per day. RESULTS: Pearson correlation coefficients for perceptions of distance and objectively measured distance to physical activity resources ranged from 0.40 (gyms, schools) to 0.54 (parks). Perceived distance to gyms and objective number of schools within 1-mile buffers were negatively associated with activity. No statistically significant relationships were found between activity and perceived or objectively measured proximity to parks. CONCLUSION: Results indicate the need for both individual and environmental intervention strategies to increase levels of physical activity among underinsured, midlife women. More work is needed to determine the most effective strategies

Impact of lipid-based nutrient supplementation (LNS) on children\u27s diet adequacy in Western Uganda

Lipid-based nutrient supplements (LNS) can help treat undernutrition; however, the dietary adequacy of children supplemented with LNS, and household utilisation patterns are not well understood. We assessed diet adequacy and the quality of complementary foods by conducting a diet assessment of 128 Ugandan children, ages 6-59 months, who participated in a 10-week programme for children with moderate acute malnutrition (MAM, defined as weight-for-age z-score \u3c -2). Caregivers were given a weekly ration of 650 kcal day (-1) (126 g day(-1)) of a peanut/ soy LNS. Two 24-h dietary recalls were administered per child. LNS was offered to 86% of targeted children at least once. Among non-breastfed children, over 90% met their estimated average requirement (EAR) cut-points for all examined nutrients. Over 90% of breastfed children met EAR cut-points for nutrient density for most nutrients, except for zinc where 11.7% met cut-points. A lower proportion of both breastfed and non-breastfed children met adjusted EARs for the specific nutritional needs of MAM. Fewer than 20% of breastfed children met EAR nutrient-density guidelines for MAM for zinc, vitamin C, vitamin A and folate. Underweight status, the presence of a father in the child\u27s home, and higher programme attendance were all associated with greater odds of feeding LNS to targeted children. Children in this community-based supplemental feeding programme who received a locally produced LNS exhibited substantial micronutrient deficiencies given the special dietary needs of this population. These results can help inform programme strategies to improve LNS targeting, and highlight potential nutrient inadequacies for consumers of LNS in community-based settings

Best-fitting prediction equations for basal metabolic rate: informing obesity interventions in diverse populations

Basal Metabolic Rate (BMR) represents the largest component of total energy expenditure and is a major contributor to energy balance. Therefore, accurately estimating BMR is critical for developing rigorous obesity prevention and control strategies. Over the past several decades, numerous BMR formulas have been developed targeted to different population groups. A comprehensive literature search revealed 248 BMR estimation equations developed using diverse ranges of age, gender, race, fat free mass, fat mass, height, waist-to-hip ratio, body mass index, and weight. A subset of 47 studies included enough detail to allow for development of meta-regression equations. Utilizing these studies, meta-equations were developed targeted to twenty specific population groups. This review provides a comprehensive summary of available BMR equations and an estimate of their accuracy. An accompanying online BMR prediction tool (available at http://www.sdl.ise.vt.edu/tutorials.html) was developed to automatically estimate BMR based on the most appropriate equation after user-entry of individual age, race, gender, and weight

Food Store Environment Modifies Intervention Effect on Fruit and Vegetable Intake among Low-Income Women in North Carolina

Background. The aim of the study is to determine how the food store environment modifies the effects of an intervention on diet among low-income women. Study Design. A 16-week face-to-face behavioral weight loss intervention was delivered among low income midlife women. Methods. The retail food environment for all women was characterized by (1) the number and type of food stores within census tracts; (2) availability of healthy foods in stores where participants shop; (3) an aggregate score of self-reported availability of healthy foods in neighborhood and food stores. Statistical Analyses. Multivariable linear regression was used to model the food store environment as an effect modifier between the intervention effect of fruit and vegetable serving change. Results. Among intervention participants with a low perception of availability of healthy foods in stores, the intervention effect on fruit and vegetable serving change was greater [1.89, 95% CI (0.48, 3.31)] compared to controls. Among intervention participants residing in neighborhoods with few super markets, the intervention effect on fruit and vegetable serving change was greater [1.62, 95% CI (1.27, 1.96)] compared to controls. Conclusion. Results point to how the food store environment may modify the success of an intervention on diet change among low-income women

Identification of a Framework for Best Practices in Nutrition Education for Low-Income Audiences

To promote effective low-income nutrition education programs, an expert panel of nutrition education and public health researchers built consensus around 28 best practices grouped into 5 domains (Program Design, Program Delivery, Educator Characteristics, Educator Training, and Evaluation) targeting direct delivery of nutrition education. These best practices can be used to assess program strengths, promote fidelity in delivery and evaluation, and design research to strengthen programs’ evidence base. A survey of Supplemental Nutrition Assistance Program–Education nutrition education leaders helped identify staff development needs and interest relative to specific best practices. Best practices can be used to identify staff development needs among frontline educators, supervisors, and program leaders in Supplemental Nutrition Assistance Program–Education, Expanded Food and Nutrition Education Program, and other programs targeting low-income audiences

Physical activity opportunities within the schedule of early care and education centers

Background: Physical activity has many benefits for young children's health and overall development, but few studies have investigated how early care and education centers allot time for physical activity, along with measured individual physical activity levels for indoor/outdoor activities during a typical day. Methods: Fifty early care and education centers in central North Carolina participated in 4 full-day observations, and 559 children aged 3-5 years within centers wore accelerometers assessing physical activity during observation days. Observation and physical activity data were linked and analyzed for associations between child activity and type of classroom activity. Results: Children averaged 51 (13) minutes per day of moderate to vigorous physical activity and 99 (18) minutes per day of light physical activity while in child care. Children averaged 6 (10) and 10 (13) minutes per day of observed outdoor and indoor daily teacher-led physical activity, respectively. Outdoor time averaged 67 (49) minutes per day, and physical activity levels were higher during outdoor time than during common indoor activities (center time, circle time, and TV time). Conclusions: Physical activity levels varied between indoor and outdoor class activities. Policy and program-related efforts to increase physical activity in preschoolers should consider these patterns to leverage opportunities to optimize physical activity within early care and education centers