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Background With the rapid increase in obesity rates, determining critical periods for weight gain and the effects of changes in fat mass is imperative. The purpose of this study was to examine changes in body weight and composition over the holiday season (Thanksgiving through New Year's) in male and female college students. Methods Subjects completed three visits: the first occurred within 2 weeks prior to Thanksgiving, the second occurred within 5 to 7 days following Thanksgiving, and the third occurred within 10 days following New Year's Day. A total of 82 healthy male and female college age subjects participated. Body composition by dual energy x-ray absorptiometry (DXA) was assessed at visits 1 and 3 while body weight was assessed at all three visits. Results Average body weight remained relatively unchanged from pre-Thanksgiving to post-New Year's (71.3 ± 14 kg vs. 71.2 ± 15 kg; P = 0.71) and, in fact, a subset of normal weight subjects lost a significant amount of body weight. However, percent body fat (25.9 ± 9 %fat vs. 27.0 ± 9 %fat; P < 0.01) and fat mass (18.3 ± 8 kg and 19.1 ± 8 kg; P < 0.01) significantly increased from pre-Thanksgiving to post-New Year's while fat-free mass (48.7 ± 12 kg and 48.3 ± 11 kg; P = 0.08) was not significantly different than the post-New Year's. A significant positive relationship (P < 0.001) between the change in BMI and percent fat, total fat mass, total fat free mass, and trunk fat mass for the pre-Thanksgiving and post-New Year's visits were found. The same significant positive relationships (P < 0.001) were also observed between the change in body weight and percent fat, total fat mass, total fat free mass, and trunk fat mass. Conclusion Despite the fact that body weight remained unchanged over the course of the holiday season, a significant increase in %body fat and fat mass was observed. With recent evidence showing marked morbidity and mortality to be associated with increased body fat (particularly abdominal adiposity), results from this study suggest body weight alone may underestimate the potentially deleterious effects of the holiday season.

Objective: To assess the validity of a new hand-held indirect calorimeter [MedGem (MG)] in the determination of resting energy expenditure (REE; kilocalories per day) in children. Research Methods and Procedures: One hundred male (n = 54) and female (n = 46) children (10.6 ± 3.2 years, 43.9 ± 19.0 kg, 146.1 ± 18.8 cm, 19.6 ± 4.9 kg/m2) participated. Children arrived at the University of Oklahoma body composition laboratory between 5:30 am and 6:15 am after an overnight fast. On arrival, subjects voided and remained quietly in the supine position for 15 minutes before testing. REE was measured by indirect calorimetry (in random order), with both the MG (sitting upright) and the criterion Delta Trac II (DT) (supine). Data are reported as the mean ± standard deviation. Results: The mean MG REE (1452 ± 355 kcal/d) was significantly higher than DT REE (1349 ± 296 kcal/d, p < 0.001). Bland-Altman analysis revealed a mean bias (MG − DT) of 104 kcal/d, with limits of agreement of −241 to +449 kcal/d. To examine the difference in subject positioning, an independent sample of 38 subjects performed the MG in its normal position (sitting) and holding the MG in a supine position. REE by the MG in the sitting position (1475 ± 350 kcal/d) was significantly (p < 0.05) higher than the MG in the supine position (1419 ± 286 kcal/d). Discussion: The mean difference in REE between MG and DT was relatively small (103 kcal/d) but significant; however, a portion of this difference may have been related to differences in subject positioning. These preliminary data indicate that the MG shows promise as a valid tool in the assessment of REE in children.

Objective To compare the accuracy of air displacement plethysmography (ADP) and dual energy x-ray absorptionmetry (DXA) in tracking changes in body composition after a 16 month weight loss intervention in overweight and obese females. Methods 93 healthy female subjects (38.9 ± 5.7 yr, 159.8 ± 5.6 cm, 76.7 ± 9.9 kg, 30.0 ± 3.4 kg/m2) completed a 16 month weight loss intervention. Eligible subjects attended 15 treatment sessions occurring over the course of 4 months with educational content including topics relating to physical activity and exercise, diet and eating behavior, and behavior modification. In the remaining 12 months, subjects underwent a lifestyle program designed to increase physical activity and improve eating habits. Before and after the intervention, subjects had their percent body fat (%fat), fat mass (FM), and fat-free mass (FFM)) assessed by DXA and ADP. Results Significant differences (p ≤ 0.001) were found between DXA and ADP at baseline %fat (46.0 % fat vs. 42.0 % fat), FM (35.3 kg vs. 32.5 kg) and FFM (40.8 kg vs. 44.2 kg) as well as at post intervention for %fat (42.1% fat vs. 38.3 % fat), FM (30.9 kg vs. 28.4 kg) and FFM (41.7 kg vs. 44.7 kg). At each time point, ADP %fat and total FM was significantly lower (p ≤ 0.001) than DXA while FFM was significantly higher (p ≤ 0.001). However, both techniques tracked %fat changes similarly considering that there were no differences between the two means. Furthermore, a Bland-Altman analysis was performed and no significant bias was observed, thus demonstrating the ability of ADP to measure body fat across a wide range of fatness. Conclusion At baseline and post weight loss, a significant difference was found between ADP and DXA. However, the results indicate both methods are highly related and track changes in %fat similarly after a weight loss program in overweight and obese females. Additionally, the mean changes in %fat were similar between the two techniques, suggesting that ADP can be translated to its use in clinical practice and research studies as DXA currently is used.

Background To determine the validity of the recently developed child-specific thoracic gas volume (TGV) prediction equations for use in air-displacement plethysmography (ADP) in diverse pediatric populations. Methods Three distinct populations were studied: European American and African American children living in Birmingham, Alabama and European children living in Lisbon, Portugal. Each child completed a standard ADP testing protocol, including a measured TGV according to the manufactures software criteria. Measured TGV was compared to the predicted TGV from current adult-based ADP proprietary equations and to the recently developed child-specific TGV equations of Fields et al. Similarly, percent body fat, derived using the TGV prediction equations, was compared to percent body fat derived using measured TGV. Results Predicted TGV from adult-based equations was significantly different from measured TGV in girls from each of the three ethnic groups (P < 0.05), however child-specific TGV estimates did not significantly differ from measured TGV in any of the ethnic or gender groups. Percent body fat estimates using adult-derived and child-specific TGV estimates did not differ significantly from percent body fat measures using measured TGV in any of the groups. Conclusion The child-specific TGV equations developed by Fields et al. provided a modest improvement over the adult-based TGV equations in an ethnically diverse group of children.

Air-displacement plethysmography holds promise as an alternative to more traditional body composition techniques, although our understanding of air-displacement plethysmography is less than complete. Specifically, factors that influence its validity and application in certain populations, for example children, the obese, and athletes, must be better understood. This review will summarize recent findings on the validity and precision of air-displacement plethysmography and will focus primarily on papers published since 2004, with particular attention on its use in infants.The most significant recent findings in the air-displacement plethysmography literature are mechanistic in nature specifically dealing with measurement issues such as heat, moisture, clothing, and recently, inter-device variability.It is important to recognize that air-displacement plethysmography can be a practical instrument in the evaluation of body composition in a wide range of populations. Therefore, based on the body of literature that has emerged, air-displacement plethysmography appears to be a suitable and reliable instrument in the assessment of body composition. Of particular interest is its use in pediatric and obese individuals, areas requiring further study. Research is also needed to help us better understand sources of measurement error.

Background The purpose of this study was to examine the accuracy of total body density and percent body fat (% fat) using air displacement plethysmography (ADP) and hydrostatic weighing (HW) in children. Methods Sixty-six male and female subjects (40 males: 12.4 ± 1.3 yrs, 47.4 ± 14.8 kg, 155.4 ± 11.9 cm, 19.3 ± 4.1 kg/m2; 26 females: 12.0 ± 1.9 yrs, 41.4 ± 7.7 kg, 152.1 ± 8.9 cm, 17.7 ± 1.7 kg/m2) were tested using ADP and HW with ADP always preceding HW. Accuracy, precision, and bias were examined in ADP with HW serving as the criterion method. Lohman's equations that are child specific for age and gender were used to convert body density to % fat. Regression analysis determined the accuracy of ADP and potential bias between ADP and HW using Bland-Altman analysis. Results For the entire group (Y = 0.835x + 0.171, R2 = 0.84, SEE = 0.007 g/cm3) and for the males (Y = 0.837x + 0.174, R2 = 0.90, SEE = 0.006 g/cm3) the regression between total body density by HW and by ADP significantly deviated from the line of identity. However in females, the regression between total body density by HW and ADP did not significantly deviate from the line of identity (Y = 0.750x + 0.258, R2 = 0.55, SEE = 0.008 g/cm3). The regression between % fat by HW and ADP for the group (Y = 0.84x + 3.81, R2 = 0.83, SEE = 3.35 % fat) and for the males (Y = 0.84x + 3.25, R2 = 0.90, SEE = 3.00 % fat) significantly deviated from the line of identity. However, in females the regression between % fat by HW and ADP did not significantly deviate from the line of identity (Y = 0.81x + 5.17, R2 = 0.56, SEE = 3.80 % fat). Bland-Altman analysis revealed no bias between HW total body density and ADP total body density for the entire group (R = 0.-22; P = 0.08) or for females (R = 0.02; P = 0.92), however bias existed in males (R = -0.37; P ≤ 0.05). Bland-Altman analysis revealed no bias between HW and ADP % fat for the entire group (R = 0.21; P = 0.10) or in females (R = 0.10; P = 0.57), however bias was indicated for males by a significant correlation (R = 0.36; P ≤ 0.05), with ADP underestimating % fat at lower fat values and overestimating at the higher % fat values. Conclusion A significant difference in total body density and % fat was observed between ADP and HW in children 10–15 years old with a potential gender difference being detected. Upon further investigation it was revealed that the study was inadequately powered, thus we recommend that larger studies that are appropriately powered be conducted to better understand this potential gender difference.

Background Air-displacement plethysmography (ADP) is becoming a popular method to assess body composition. Several studies have shown certain types of clothing can affect measurements of body density, however no study has specifically investigated the effect of cotton gym shorts and spandex bicycle shorts on body density. Methods Thirty-seven males (23.0 ± 3.2 yr., 177.3 ± 5.4 cm., 74.8 ± 7.5 kg.) and thirty-eight females (23.7 ± 5.3 yr., 163.6 ± 8.4 cm., 57.1 ± 7.0 kg.) had their body density measured by ADP in three clothing schemes: 1) a tight fitting Speedo® swim suit (criterion measure), 2) cotton gym shorts, and 3) spandex bicycle shorts. The clothing was provided by the University of Oklahoma Body Composition Laboratory and the testing schemes were performed in random order. Results The regression of body density by the criterion measure against body density while wearing cotton gym shorts for the entire group (y = 0.001 + 0.991x, SEE = 0.003 g/cm3) and the females (y = 0.059 + 0.934x, SEE = 0.003 g/cm3) did not significantly deviate from the line of identity. However in males the regression significantly deviated from the line of identity (y = 0.052 + 0.944x, SEE = 0.002 g/cm3). Body density by the criterion measure and body density while wearing spandex bicycle shorts did not significantly differ from the line of identity for the entire group (y = -0.018 + 1.013x SEE = 0.003 g/cm3), in males (y = -0.002 + 1.001x, SEE = 0.003 g/cm3), or females (y = 0.073 + 0.925x, SEE = 0.003 g/cm3). Residual plot analysis revealed no group or gender bias in either the cotton gym shorts or in the spandex bicycle shorts. Conclusion It would appear bicycle spandex shorts are an acceptable alternative to a Speedo® like swim suit, however we advise that subjects adhere to the strict clothing protocol that is recommended by the manufacturer.

Objective: To develop child-specific thoracic gas volume (TGV) prediction equations for use in air-displacement plethysmography in 6- to 17-year-old children. Research Methods and Procedures: Study 1 developed TGV prediction equations using anthropometric variables after completing a measured TGV and air-displacement plethysmography test in 224 healthy boys and girls (11.2 ± 3.2 years, 45.3 ± 18.7 kg, 149.9 ± 18.5 cm). Study 2 cross-validated the prediction equations in a separate cohort of 62 healthy boys and girls (11.2 ± 3.4 years, 44.2 ± 15.3 kg, 149.4 ± 19.3 cm). Results: In Study 1 (development of TGV prediction equations), the quadratic relationship using height as the independent variable and the measured TGV as the dependent variable yielded the highest adjusted R2 and the lowest SE of estimate in both genders, thus producing the following prediction equations: TGV = 0.00056 × H2 − 0.12422 × H + 8.15194 (boys) and TGV = 0.00044 × H2 − 0.09220 × H + 6.00305 (girls). In Study 2 (cross-validation), no significant difference between the predicted and measured TGVs (−0.018 ± 0.377 liters) was observed. The regression between the measured TGV and the predicted TGV yielded a slope and intercept that did not significantly differ from the line of identity. Prediction accuracy was good as indicated by a high R2 (0.862) and low SE of estimate (0.369 liters). Discussion: The new child-specific TGV prediction equations accurately, precisely, and without bias estimated the actual TGV of 6- to 17-year-old children.

Small detection distances coupled with rapid movements require copepods to respond to stimuli with behavioral latencies on the order of milliseconds. Receiving adequate sensory information in such a short time necessitates extremely rapid firing rates of the efferent receptors. Here we show that copepod mechanoreceptors can fire at frequencies up to 5 kHz in response to fluid mechanical stimuli. Neural activity at these frequencies enables these animals to code for a range of fluid velocities thus providing important information regarding the nature of different fluid disturbances.

Syringe pumps are traditionally used to infuse tracers in metabolic research because they are perceived to be more accurate and precise than peristaltic pumps. This study evaluated the accuracy (actual v programmed infusion rate) and precision (reproducibility of infusion) of a peristaltic pump (Gemini PC 2; IMED, San Diego, CA) and a syringe pump (Model 22; Harvard Apparatus, Natick, MA) for metabolic research. In one protocol, saline delivery was measured in vitro in 5 trials at 4 flow rates: 3, 30, 150, and 300 mL/h. In the second protocol, basal glycerol rate of appearance (Ra) was determined in vivo in 5 women on 2 consecutive days. On day 1, [2-(13C)]glycerol was infused with 1 pump and [1,1,2,3,3-(2H5)]glycerol with the other. On day 2, the opposite pattern was used. The accuracy of the 2 pumps was the same (error approximately 2%). In addition, both the syringe and the peristaltic pumps were very precise, with coefficients of variation (CV)

This review will focus chiefly on recently published studies utilizing air-displacement plethysmography (i.e. BOD POD) in geriatric populations. This innovative technology has been available commercially since 1995. As the test procedure is relatively easy to perform and quick, it may provide an improvement in body composition testing, especially in older individuals with poor ambulation and health.This review will explain in a concise and detailed manner the underlying principles of air-displacement plethysmography specifically related to the BOD POD. Second, it will review the studies using this new technology in comparison with more commonly used techniques (hydrostatic weighing, dual energy X-ray absorptiometry, deuterium oxide, multi-compartmental models) for body composition analysis in geriatric populations. Third, it will provide a direction for future studies.A review of the current body of literature in which air-displacement plethysmography was used is beginning to emerge with a clear picture. Although this technique is still new, it appears that air-displacement plethysmography is a valid and reliable alternative to more traditional body composition techniques, as indicated by small mean differences between techniques. This has special implications in a geriatric population because traditional techniques are difficult to perform in individuals with joint pain, ambulation issues, and overall poor health.

The main problem with terraforming is finding planets with workable initial parameters: large enough, temperate enough, wet enough, axial spin not too fast or too slow, a magnetic field, etc. We consider a novel method of creating habitable worlds for humanity by enclosing airless and sterile planets, moons, and even large asteroids within engineered shells supported by breathable atmospheres. Beneath the shell an earthlike environment could be formed similar in almost all respects to that of Earth except for gravity, regardless of the distance to the sun or other star. These would be natural worlds, not merely large habitats, stable across historic timescales at least, each comprising a full self‐sustaining ecology, which might evolve in interesting and distinct directions over time. This approach requires no fundamental breakthroughs in science or physics but does require progress in energy production, space transportation, and environmental and materials sciences.

The effect of relative body fat mass on exercise-induced stimulation of lipolysis and fatty acid oxidation was evaluated in 15 untrained men (5 lean, 5 overweight, and 5 obese with body mass indexes of 21 ± 1, 27 ± 1, and 34 ± 1 kg/m2, respectively, and %body fat ranging from 12 to 32%). Palmitate and glycerol kinetics and substrate oxidation were assessed during 90 min of cycling at 50% peak aerobic capacity (V̇o2 peak) by use of stable isotope-labeled tracer infusion and indirect calorimetry. An inverse relationship was found between %body fat and exercise-induced increase in glycerol appearance rate relative to fat mass ( r2= 0.74; P < 0.01). The increase in total fatty acid uptake during exercise [(μmol/kg fat-free mass) × 90 min] was ∼50% smaller in obese (181 ± 70; P < 0.05) and ∼35% smaller in overweight (230 ± 71; P < 0.05) than in lean (354 ± 34) men. The percentage of total fatty acid oxidation derived from systemic plasma fatty acids decreased with increasing body fat, from 49 ± 3% in lean to 39 ± 4% in obese men ( P < 0.05); conversely, the percentage of nonsystemic fatty acids, presumably derived from intramuscular and possibly plasma triglycerides, increased with increasing body fat ( P < 0.05). We conclude that the lipolytic response to exercise decreases with increasing adiposity. The blunted increase in lipolytic rate in overweight and obese men compared with lean men limits the availability of plasma fatty acids as a fuel during exercise. However, the rate of total fat oxidation was similar in all groups because of a compensatory increase in the oxidation of nonsystemic fatty acids.

Laboratory-based body-composition techniques include hydrostatic weighing (HW), dual-energy X-ray absorptiometry (DXA), measurement of total body water (TBW) by isotope dilution, measurement of total body potassium, and multicompartment models. Although these reference methods are used routinely, each has inherent practical limitations. Whole-body air-displacement plethysmography is a new practical alternative to these more traditional body-composition methods. We reviewed the principal findings from studies published between December 1995 and August 2001 that compared the BOD POD method (Life Measurement, Inc, Concord, CA) with reference methods and summarized factors contributing to the different study findings. The average of the study means indicates that the BOD POD and HW agree within 1% body fat (BF) for adults and children, whereas the BOD POD and DXA agree within 1% BF for adults and 2% BF for children. Few studies have compared the BOD POD with multicompartment models; those that have suggest a similar average underestimation of approximate 2-3% BF by both the BOD POD and HW. Individual variations between 2-compartment models compared with DXA and 4 -compartment models are partly attributable to deviations from the assumed chemical composition of the body. Wide variations among study means, -4.0% to 1.9% BF for BOD POD - HW and -3.0% to 1.7% BF for BOD POD - DXA, are likely due in part to differences in laboratory equipment, study design, and subject characteristics and in some cases to failure to follow the manufacturer's recommended protocol. Wide intersubject variations between methods are partly attributed to technical precision and biological error but to a large extent remain unexplained. On the basis of this review, future research goals are suggested.

This study was designed to compare the accuracy and bias in estimates of total body density (Db) by hydrostatic weighing (HW) and the BOD POD, and percent body fat (%fat) by the BOD POD with the four-compartment model (4C model) in 42 adult females. Furthermore, the role of the aqueous and mineral fractions in the estimation of body fat by the BOD POD was examined.Total body water was determined by isotope dilution ((2)H(2)0) and bone mineral was determined by dual-energy x-ray absorptiometry. Db and %fat were determined by the BOD POD and HW. The 4C model of Baumgartner was used as the criterion measure of body fat.HW Db (1.0352 g x cm(-3)) was not statistically different (P = 0.35) from BOD POD Db (1.0349 g x cm(-3)). The regression between Db by HW and the BOD POD significantly deviated from the line of identity (Db by HW = 0.90 x Db by BOD POD + 0.099; R(2) = 0.94). BOD POD %fat (28.8%) was significantly lower (P0.01) than %fat by the 4C model (30.6%). The regression between %fat by the 4C model and the BOD POD significantly deviated from the line of identity (%fat by 4C model = 0.88 x %fat by BOD POD + 5.41%; R(2) = 0.92). BOD POD Db and %fat showed no bias across the range of fatness. Only the aqueous fraction of the fat-free mass (FFM) had a significant correlation with the difference in %fat between the 4C model and the BOD POD.These data indicate that the BOD POD underpredicted body fat as compared with the 4C model, and the aqueous fraction of the FFM had a significant effect on estimates of %fat by the BOD POD.

Standardized methods for estimating the toxicity of anthropogenic compounds to aquatic organisms frequently fail to consider key elements of the test organisms' environment. Aquatic organisms exist in a fluid environment, and fluid dynamics may have an important influence on the response to toxicants. Rotifers are one of the three major groups of zooplankton and have been increasingly utilized in standardized toxicity testing. However, like other toxicity tests, assays with the species Brachionus calyciflorus are performed under static conditions in the absence of fluid motion. We investigated how fluid motion modifies pentachlorophenol (PCP) toxicity to B. calyciflorus using 24 h acute and 48 h reproductive toxicity tests. Estimates of PCP LC50s and reproduction EC50s in static conditions decreased from 738 and 1082 microg l(-1), respectively, to as low as 262 and 136 microg l(-1), respectively, in fluid motion. Flow analysis indicated that increased toxicant sensitivity can occur at ecologically relevant levels of fluid motion. Mechanistic studies indicated that fluid motion/toxicant interactions may result from the ability of fluid motion to cause shear stress, alter toxicant uptake, and/or alter the bioavailability of food. As fluid motion may have an important effect on the life histories of a wide variety of aquatic organisms, fluid motion/toxicant interactions may be an important consideration in other standard test organisms. These results raise questions about the accuracy of ecological risk assessments based on toxicity data from static conditions.

The purpose of this study was to determine what effects 26 wk of resistance training have on resting energy expenditure (REE), total free-living energy expenditure (TEE), activity-related energy expenditure (AEE), engagement in free-living physical activity as measured by the activity-related time equivalent (ARTE) index, and respiratory exchange ratio (RER) in 61- to 77-yr-old men ( n = 8) and women ( n = 7). Before and after training, body composition (four-compartment model), strength, REE, TEE (doubly labeled water), AEE (TEE − REE + thermic response to meals), and ARTE (AEE adjusted for energy cost of standard activities) were evaluated. Strength (36%) and fat-free mass (2 kg) significantly increased, but body weight did not change. REE increased 6.8%, whereas resting RER decreased from 0.86 to 0.83. TEE (12%) and ARTE (38%) increased significantly, and AEE (30%) approached significance ( P = 0.06). The TEE increase remained significant even after adjustment for the energy expenditure of the resistance training. In response to resistance training, TEE increased and RER decreased. The increase in TEE occurred as a result of increases in both REE and physical activity. These results suggest that resistance training may have value in increasing energy expenditure and lipid oxidation rates in older adults, thereby improving their metabolic profiles.

OBJECTIVE: The objective of this study was to examine the influence of body weight and body composition on aspects of aerobic fitness. Our hypothesis was that increased body weight, specifically increased fat mass (FM), would not limit VO2max relative to fat-free mass (FFM), but would reduce maximal and sub-maximal VO2max relative to body weight. DESIGN: We used data from two ongoing studies. In Study 1 a cross-sectional analysis of 129 children across a wide spectrum of body composition was performed. In Study 2 we examined data from 31 overweight women before and after weight loss. METHODS: VO2max was measured using a treadmill test. Sub-maximal aerobic capacity was evaluated with respiratory exchange ratio (RER), heart-rate (HR), and oxygen uptake relative to VO2max at a given workload (%VO2max). Body composition was assessed using dual energy X-ray absorptiometry (DXA) (Study 1) and a four-compartment model (Study 2). RESULTS: In Study 1, FFM was the strongest determinant of VO2max (r=0.87; P

A disciplina relativamente nova de avaliação de risco ambiental está sendo amplamente aplicada como uma ferramenta de gestão ambiental nos países mais industrializados da América do Norte, Europa e Ásia. Os benefícios de se considerar propriamente o risco ambiental na interpretação e comunicação dos resultados dos estudos e das simulações hidrológicas incluem um melhoramento na gestão da saúde pública e a proteção do meio ambiente em geral. Este artigo discute a importância da avaliação do risco ambiental nas sociedades modernas. Conceitos chave relativos à avaliação do risco ambiental são introduzidos e definidos.

For 10 years, the Centers for Disease Control and Prevention (CDC) and the American College of Sports Medicine (ACSM) have called on U.S. adults to incorporate moderate intensity physical activity (MPA) into their daily routine. Given that one fourth of U.S. women participate in no physical activities, it is important to assess whether messages promoting MPA, such as those in the mass media, help women adequately understand the intensity of activity required to meet the recommendation or whether additional methods may be needed.

The timing and magnitude of an escape reaction is often the determining factor governing a copepod’s success at avoiding predation. Copepods initiate rapid and directed escapes in response to fluid signals created by predators; however little is known about how copepods modulate their behavior in response to additional sensory input. This study investigates the effect of light level on the escape behavior of Calanus finmarchicus. A siphon flow was used to generate a consistent fluid signal and the behavioral threshold and magnitude of the escape response was quantified in the dark and in the light. The results show that C. finmarchicus initiated their escape reaction further from the siphon and traveled with greater speed in the light than in the dark. However, no difference was found in the escape distance. These results suggest that copepods use information derived from multiple sensory inputs to modulate the sensitivity and strength of the escape in response to an increase risk of predation. Population and IBM models that predict optimal vertical distributions of copepods in response to visual predators need to consider changes in the copepod’s behavioral thresholds when predicting predation risk within the water column.

e26333 UVB alters photosynthetic rate, fatty acid profiles and morphological characteristics of phytoplankton. Copepods, important grazers of primary production, select algal cells based upon their size, morphological traits, nutritional status, and motility. We investigated the grazing rates of the copepod Calanus finmarchicus on the diatom Thalassiosira weissflogii cultured under 3 levels of ultraviolet radiation (UVR): photosynthetically active radiation (PAR) only (4 kJ-m−2/day), and PAR supplemented with UVR radiation at two intensities (24 kJ-m−2/day and 48 kJ-m−2/day). There was no significant difference in grazing rates between the PAR only treatment and the lower UVR treatment. However, grazing rates were significantly (~66%) higher for copepods feeding on cells treated with the higher level of UVR. These results suggest that a short-term increase in UVR exposure results in a significant increase in the grazing rate of copepods and, thereby, potentially alters the flow rate of organic matter through this component of the ecosystem.

Background Years spent in college represents a critical time for obesity development though little information is known regarding how body weight and composition changes beyond the first year of college. The aim of this study was to investigate changes in body weight and composition and the factors influencing those changes among sophomore females. Methods Body composition by dual energy X-ray absorptiometry was obtained in participants beginning during their freshman year and continued through their sophomore year. Results No difference was observed between sophomore year fall and spring visits for body weight (60.4 versus 60.6 kg) or fat mass (19.3 versus 18.7 kg). However, a significant (P ≤ 0.05) decrease was observed for body fat (31.9 versus 30.9 %fat) and a significant increase was observed for fat-free mass (37.7 versus 38.4 kg). Participants living off campus significantly (P ≤ 0.05) declined in body fat (33.0 versus 31.0 %fat) and fat mass (19.4 versus 18.2 kg) and increased in fat-free mass (36.1 versus 37.2 kg) with no differences in those living on campus. Conclusion No change in body weight was observed in females during their sophomore year. However, an increase in fat-free mass accompanied with a decrease in fat mass resulted in a decrease in body fat. Participants living off campus had favorable changes in their body composition by means of decreasing %fat and fat mass while increasing fat-free mass. Participants living on campus did not demonstrate these favorable changes.

To investigate the effect of body temperature and moisture on body fat (%fat), volume and density by air-displacement plethysmography (BOD POD). %fat, body volume and density by the BOD POD before (BOD PODBH) and immediately following hydrostatic weighing (BOD PODFH) were performed in 32 healthy females (age (yr) 33 ± 11, weight (kg) 64 ± 14, height (cm) 167 ± 7). Body temperature and moisture were measured prior to BOD PODBH and prior to BOD PODFH with body moisture defined as the difference in body weight (kg) between the BOD PODBH and BOD PODFH measurements. BOD PODFH %fat (27.1%) and body volume (61.5 L) were significantly lower (P ≤ 0.001) and body density (1.0379 g/cm3) significantly higher (P ≤ 0.001) than BOD PODBH %fat (28.9%), body volume (61.7 L), and body density (1.0341 g/cm3). A significant increase in body temperature (~0.6°C; P ≤ 0.001) and body moisture (0.08 kg; P ≤ 0.01) were observed between BOD PODBH and BOD PODFH. Body surface area was positively associated with the difference in %fat independent of changes in body temperature and moisture, r = 0.30, P < 0.05. These data demonstrate for the first time that increases in body heat and moisture result in an underestimation of body fat when using the BOD POD, however, the precise mechanism remains unidentified.

A numerical model of seed dispersal by wind is presented which integrates the effects of wind speeds and directions during seed dispersal season, height of seed release, seed terminal velocities and effects of wind speed/atmospheric humidity on seed release rates. A histogram of terminal velocities of maple ( Acer spp.) seeds and climatic data of Minneapolis, MN, are used to derive a seed dispersal pattern for an isolated tree. Under these conditions seed dispersal is asymmetric around the seed source. Maximum seed deposition occurs 100 m northeast of the seed source (13 seeds m −2 per 10 6 seeds released); this declines to 1 seed m −2 at 300 m and 0.03 seeds m −2 at 600 m distance from the seed source.

We have predicted yearly, growing season, and growing season daylight normalized air concentrations ( C Q ) of an inert gas tracer for a point source release near Oak Ridge, Tennessee, using local meteorological data collected for the years 1967–1969. Pasquill-Gifford atmospheric stability categories were determined using the vertical temperature gradient method, and concentrations were determined assuming Gaussian plume transport of a nondepositing contaminant. A seasonal variability in the wind rose was found, and an accompanying variability in the geographical distribution of C Q was identified. Values of C Q typically changed by a factor of two between yearly and growing season daylight hours and for receptor points located up to km distance from the source. These results suggest that yearly average computations may in certain cases be inappropriate for determining compliance with air quality standards during the growing season or where a seasonal activity pattern exists.

Selection of appropriate values for model input parameters requires knowledge of the distribution of these parameters. The TERPED computer code is a versatile methodology for determining with what confidence a parameter set may be considered to have a normal or lognormal frequency distribution and for determining appropriate representative values. Several measures of central tendency are computed. Other options include computation of the chi-square statistic, the Kolmogorov-Smirnov (KS) non-parametric statistic, and Pearson's correlation coefficient. Our implementation of the KS test uses algorithms that yield results valid for both large and small sample size. Cumulative probability plots are produced either in high resolution (pen and ink for film) or in printer-plot form.

It is well known that a polynomial f ( X ) f(X) over a commutative ring R R with identity is nilpotent if and only if each coefficient of f ( X ) f(X) is nilpotent; and that f ( X ) f(X) is a zero divisor in R [ X ] R[X] if and only if f ( X ) f(X) is annihilated by a nonzero element of R R . This paper considers the problem of determining when a power series g ( X ) g(X) over R R is either nilpotent or a zero divisor in R [ [ X ] ] R[[X]] . If R R is Noetherian, then g ( X ) g(X) is nilpotent if and only if each coefficient of g ( X ) g(X) is nilpotent; and g ( X ) g(X) is a zero divisor in R [ [ X ] ] R[[X]] if and only if g ( X ) g(X) is annihilated by a nonzero element of R R . If R R has positive characteristic, then g ( X ) g(X) is nilpotent if and only if each coefficient of g ( X ) g(X) is nilpotent and there is an upper bound on the orders of nilpotency of the coefficients of g ( X ) g(X) . Examples illustrate, however, that in general g ( X ) g(X) need not be nilpotent if there is an upper bound on the orders of nilpotency of the coefficients of g ( X ) g(X) , and that g ( X ) g(X) may be a zero divisor in R [ [ X ] ] R[[X]] while g ( X ) g(X) has a unit coefficient.

each ie ω0} and we define A R [[X]] to be the ideal of R [[X]] which is generated by A. Then A R [[X]] = {f(X): Af S B for some finitely generated ideal B of R with B £ A}. It is clear that A iϋ [[X]] S A [[X]]; equality holds if and only if each countably generated ideal of R contained in A is contained in a finitely generated ideal of R contained in A. In particular, if V is a valuation ring containing an ideal A which is countably generated but not finitely generated, then A V[[X]] c A [[X]]. Finally, we note that if A is an ideal of i2, then R [[X]]/A [[X]] ~ (R/A) [[X]]; hence A [[X]] is a prime ideal of R [[X]] if and only if A is a prime ideal of R.

Background More people than ever are considered obese and the resulting health problems are evident. These facts highlight the need for identification of critical time periods for weight gain. Therefore the purpose was to assess potential changes that occur in body weight during the Thanksgiving holiday break in college students. Methods 94 college students (23.0 ± 4.6 yrs, 72.1 ± 14.0 kg, 172.6 ± 9.3 cm, 24.0 ± 3.9 kg/m2) reported to the human body composition laboratory at the University of Oklahoma following a 6-hour fast with testing occurring prior to, and immediately following the Thanksgiving holiday break (13 ± 3 days). Body weight (BW) was assessed using a balance beam scale while participants were dressed in minimal clothing. Paired t-tests were used to assess changes in BW pre and post Thanksgiving holiday with additional analysis by gender, body mass index (BMI), and class standing (i.e. undergraduate vs. graduate). Results Overall, a significant (P < 0.05) increase in BW was found between pre (72.1 kg) and post (72.6 kg) Thanksgiving holiday. When stratified by gender and class standing a significant (P < 0.05) increase in body weight was observed between the pre and post Thanksgiving holiday in males (0.6 kg), females (0.4 kg) and graduate students (0.8 kg). When participants were classified by BMI as normal or as overweight/obese, a significant 1.0 kg BW gain was found (P < 0.05) in the overweight/obese (≥25 kg/m2) group compared to a non significant 0.2 kg gain in the normal group (2). Conclusion These data indicate that participants in our study gained a significant amount of BW (0.5 kg) during the Thanksgiving holiday. While an increase in BW of half a kilogram may not be cause for alarm, the increase could have potential long-term health consequences if participants retained this weight gain throughout the college year. Additionally, because the overweight/obese participants gained the greatest amount of BW, this group may be at increased risk for weight gain and further obesity development during the holiday season.

(1958). Teaching the Accountant's Role in Budgeting. The Journal of Business Education: Vol. 33, No. 8, pp. 325-326.

SUMMARY A serologically distinct infectious bronchitis virus was isolated from clinically affected broilers in Arkansas. In each case the birds had been vaccinated 30 to 50 days previously with commercial Newcastle-bronchitis vaccines. The clinical history and isolation methods are described.