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Search Results: 1 - 10 of 224021 matches for " Tanis R Fenton "
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A new growth chart for preterm babies: Babson and Benda's chart updated with recent data and a new format
Tanis R Fenton
BMC Pediatrics , 2003, DOI: 10.1186/1471-2431-3-13
Abstract: The literature was searched from 1980 to 2002 for more recent data to complete the pre and post term sections of the chart. Data were selected from population studies with large sample sizes. Comparisons were made between the new chart and the Babson and Benda graph. To validate the growth chart the growth results from the National Institute of Child Health and Human Development Neonatal Research Network (NICHD) were superimposed on the new chart.The new data produced curves that generally followed patterns similar to the old growth graph. Mean differences between the curves of the two charts reached statistical significance after term. Babson's 10th percentiles fell between the new data percentiles: the 5th to 17th for weight, the 5th and 15th for head circumference, and the 6th and 16th for length. The growth patterns of the NICHD infants deviated away from the curves of the chart in the first weeks after birth. When the infants reached an average weight of 2 kilograms, those with a birthweight in the range of 700 to 1000 grams had achieved greater than the 10th percentile on average for head growth, but remained below the 3rd percentile for weight and length.The updated growth chart allows a comparison of an infant's growth first with the fetus as early as 22 weeks and then with the term infant to 10 weeks. Comparison of the size of the NICHD infants at a weight of 2 kilograms provides evidence that on average preterm infants are growth retarded with respect to weight and length while their head size has caught up to birth percentiles. As with all meta-analyses, the validity of this growth chart is limited by the heterogeneity of the data sources. Further validation is needed to illustrate the growth patterns of preterm infants to older ages.Growth monitoring is a part of the medical and nutritional assessment of preterm infants. Growth charts provide the basis for this assessment by providing a comparison to a reference which allows for a visual picture of both
Cord blood calcium, phosphate, magnesium, and alkaline phosphatase gestational age-specific reference intervals for preterm infants
Tanis R Fenton, Andrew W Lyon, M Sarah Rose
BMC Pediatrics , 2011, DOI: 10.1186/1471-2431-11-76
Abstract: Cross-sectional study. 702 babies were identified as candidates for this study in a regional referral neonatal unit. After exclusions (for anomalies, asphyxia, maternal magnesium sulfate administration, and death), relationships were examined between cord blood serum laboratory analytes (calcium, phosphate, magnesium, alkaline phosphatase, and albumin-adjusted calcium) with gestation age and also with maternal and neonatal variables using multiple linear regression. Infants with influential pathological conditions were omitted from the development of gestational age specific reference intervals for the following categories: 23-27, 28-31, 32-34, 35-36 and > 36 weeks.Among the 506 preterm and 54 terms infants included in the sample. Phosphate, magnesium, and alkaline phosphatase in cord blood serum decreased with gestational age, calcium increased with gestational age. Those who were triplets, small for gestational age, and those whose mother had pregnancy-induced hypertension were influential for most of the analytes. The reference ranges for the preterm infants ≥ 36 weeks were: phosphate 1.5 to 2.6 mmol/L (4.5 to 8.0 mg/dL), calcium: 2.1 to 3.1 mmol/L (8.3 to 12.4 mg/dL); albumin-adjusted calcium: 2.3 to 3.2 mmol/L (9.1 to 12.9 mg/dL); magnesium 0.6 to 1.0 mmol/L (1.4 to 2.3 mg/dL), and alkaline phosphatase 60 to 301 units/L.These data suggest that gestational age, as well as potentially pathogenic maternal and neonatal variables should be considered in the development of reference intervals for preterm infants.In addition to the structural roles calcium, phosphate, and magnesium have in bone, these minerals also have key roles in most cellular, physiological and biochemical processes. Pediatric Societies recommend that preterm infants grow similar to the fetus [1-3], and maintain fetal concentrations in blood and tissues [1,2]. Experts on bone mineralization of preterm infants recommend that cord blood serum phosphate be maintained greater than 1.5 mmol/L (4.5 mg/d
Phosphate decreases urine calcium and increases calcium balance: A meta-analysis of the osteoporosis acid-ash diet hypothesis
Tanis R Fenton, Andrew W Lyon, Michael Eliasziw, Suzanne C Tough, David A Hanley
Nutrition Journal , 2009, DOI: 10.1186/1475-2891-8-41
Abstract: Literature was identified through computerized searches regarding phosphate with surrogate and/or direct markers of bone health, and was assessed for methodological quality. Multiple linear regression analyses, weighted for sample size, were used to combine the study results. Tests of interaction included stratification by calcium intake and degree of protonation of the phosphate supplement.Twelve studies including 30 intervention arms manipulated 269 subjects' phosphate intakes. Three studies reported net acid excretion. All of the meta-analyses demonstrated significant decreases in urine calcium excretion in response to phosphate supplements whether the calcium intake was high or low, regardless of the degree of protonation of the phosphate supplement. None of the meta-analyses revealed lower calcium balance in response to increased phosphate intakes, whether the calcium intake was high or low, or the composition of the phosphate supplement.All of the findings from this meta-analysis were contrary to the acid ash hypothesis. Higher phosphate intakes were associated with decreased urine calcium and increased calcium retention. This meta-analysis did not find evidence that phosphate intake contributes to demineralization of bone or to bone calcium excretion in the urine. Dietary advice that dairy products, meats, and grains are detrimental to bone health due to "acidic" phosphate content needs reassessment. There is no evidence that higher phosphate intakes are detrimental to bone health.Phosphate is generously supplied in the diet through meat, grains and dairy products, and increasingly in recent decades, it is added to foods as food additives [1]. However, the understanding of dietary phosphate's role on bone health is not clear. While phosphate is a fundamental mineral component of hydroxyapatite, the principal structural element of bone, the acid-ash hypothesis posits that dietary phosphate, a marker of the metabolic production of acid, is detrimental to bone [
Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill's epidemiologic criteria for causality
Tanis R Fenton, Suzanne C Tough, Andrew W Lyon, Misha Eliasziw, David A Hanley
Nutrition Journal , 2011, DOI: 10.1186/1475-2891-10-41
Abstract: Systematic review and meta-analysis. We systematically searched published literature for randomized intervention trials, prospective cohort studies, and meta-analyses of the acid-ash or acid-base diet hypothesis with bone-related outcomes, in which the diet acid load was altered, or an alkaline diet or alkaline salts were provided, to healthy human adults. Cellular mechanism studies were also systematically examined.Fifty-five of 238 studies met the inclusion criteria: 22 randomized interventions, 2 meta-analyses, and 11 prospective observational studies of bone health outcomes including: urine calcium excretion, calcium balance or retention, changes of bone mineral density, or fractures, among healthy adults in which acid and/or alkaline intakes were manipulated or observed through foods or supplements; and 19 in vitro cell studies which examined the hypothesized mechanism. Urine calcium excretion rates were consistent with osteoporosis development; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion. Several weaknesses regarding the acid-ash hypothesis were uncovered: No intervention studies provided direct evidence of osteoporosis progression (fragility fractures, or bone strength as measured using biopsy). The supporting prospective cohort studies were not controlled regarding important osteoporosis risk factors including: weight loss during follow-up, family history of osteoporosis, baseline bone mineral density, and estrogen status. No study revealed a biologic mechanism functioning at physiological pH. Finally, randomized studies did not provide evidence for an adverse role of phosphate, milk, and grain foods in osteoporosis.A causal association between dietary acid load and osteoporotic bone disease is not supported by evidence and there is no evidence that an alkaline diet is protective of bone health.The concept that the modern diet produces excess acid, which causes several diseases of modern socie
Low urine pH and acid excretion do not predict bone fractures or the loss of bone mineral density: a prospective cohort study
Tanis R Fenton, Misha Eliasziw, Suzanne C Tough, Andrew W Lyon, Jacques P Brown, David A Hanley
BMC Musculoskeletal Disorders , 2010, DOI: 10.1186/1471-2474-11-88
Abstract: The objectives of this study were to determine whether 1) low urine pH, or 2) acid excretion in urine [sulfate + chloride + 1.8x phosphate + organic acids] minus [sodium + potassium + 2x calcium + 2x magnesium mEq] in fasting morning urine predict: a) fragility fractures; and b) five-year change of bone mineral density (BMD) in adults.Design: Cohort study: the prospective population-based Canadian Multicentre Osteoporosis Study. Multiple logistic regression was used to examine associations between acid excretion (urine pH and urine acid excretion) in fasting morning with the incidence of fractures (6804 person years). Multiple linear regression was used to examine associations between acid excretion with changes in BMD over 5-years at three sites: lumbar spine, femoral neck, and total hip (n = 651). Potential confounders controlled included: age, gender, family history of osteoporosis, physical activity, smoking, calcium intake, vitamin D status, estrogen status, medications, renal function, urine creatinine, body mass index, and change of body mass index.There were no associations between either urine pH or acid excretion and either the incidence of fractures or change of BMD after adjustment for confounders.Urine pH and urine acid excretion do not predict osteoporosis risk.Osteoporosis is a disease that causes pain, disability, reduced quality of life [1], mortality [2], and places substantial demands on health care budgets [3,4]. According to the acid-ash hypothesis, the modern diet produces residual acid after metabolism [5-7]. This diet-derived acid is thought to be buffered by bicarbonate from bone, followed by bone calcium excretion in the urine [5-7].Numerous papers in the medical literature (experimental trials [6-14], cross sectional studies [5,15], prospective studies [16-19], and animal models [20]) identify the potential acid load of the diet as a risk factor for osteoporosis. Well-respected textbooks [21] and reference works [22,23] uphold this concept
Effect of adult leader participation on physical activity in children  [PDF]
Tanis J. Hastmann, Karla E. Foster, Richard R. Rosenkranz, Sara K. Rosenkranz, David A. Dzewaltowski
Open Journal of Preventive Medicine (OJPM) , 2012, DOI: 10.4236/ojpm.2012.24061
Abstract: Background: Participation in physically active games is one way to increase energy expendture in children. However, it is unknown whether adult leader participation (LP) in games can impact children’s physical activity (PA) levels. The purpose of this study was to examine the influence of LP compared to no LP on PA levels among children participating in organized active games. Methods: Children (n = 14) in grades 4-6 (Male = 42.8%, White = 50%, Overweight/ Obese = 42.8%) participated in four active games across two consecutive days. Each day, children participated in two 16-minute games and received verbal encouragement from an adult leader. Each game was divided into four-minute intervals alternating between LP or no LP. LP was counter-balanced across two days. Each child wore an Actigraph GT1M accelerometer. Time spent in moderate-to-vigorous PA (MVPA), vigorous PA (VPA), and sedentary behavior (SB) was determined by Freedson’s MET prediction. Data were analyzed using a condition (LP or no LP) by game repeated-measures ANCOVA. Results: Children participated in MVPA 52.3% of game time across all games. There were no differences in MVPA, VPA, and SB by gender, weight status, or ethnicity. LP and no LP conditions were not different for MVPA, VPA, or SB. Conclusions: These results show no effect of LP on PA in children during active games. It may be that LP could not increase PA because the children were already exhibiting high levels of MVPA.
Magnetic analyses of isosceles tricobalt(II) complexes containing two types of octahedral high-spin cobalt(II) ions  [PDF]
Hiroshi Sakiyama, Harry Adams, David E. Fenton, Laura R. Cummings, Paul E. McHugh, Hisashi Okawa
Open Journal of Inorganic Chemistry (OJIC) , 2011, DOI: 10.4236/ojic.2011.13005
Abstract: The observed magnetic data for two isosceles tricobalt(II) complexes have been successfully analyzed, considering the axial distortion around each cobalt(II) ion, the local spin-orbit coupling, the anisotropic exchange interactions, and the intermolecular exchange interactions. The complexes each contains two types of octahedral high-spin cobalt(II) ions (CoA and CoB) in the shape of an isosceles triangle (CoA1–CoB–CoA2), and the contribution of the orbital angular momentum is significant. The exchange interaction between the CoA and CoB ions is practically negligible (J = ~ 0), whereas the interaction between the CoA1 and CoA2 ions is ferromagnetic (J’ > 0) for both complexes.
Five Dwarf Novae with Orbital Periods Below Two Hours
J. R. Thorstensen,W. H. Fenton
Physics , 2002, DOI: 10.1086/345103
Abstract: We give mean spectra and report orbital periods Porb based on radial velocities taken near minimum light for five dwarf novae, all of which prove to have Porb less than 2 hr. The stars and their periods are KX Aql, 0.06035(3) d; FT Cam, 0.07492(8) d; PU CMa, 0.05669(4) d; V660 Her, 0.07826(8) d;, and DM Lyr, 0.06546(6). The emission lines in KX Aql are notably strong and broad, and the other stars' spectra appear generally typical for short-period dwarf novae. We observed FT Cam, PU CMa, and DM Lyr on more than one observing run and constrain their periods accordingly. Differential time-series photometry of FT Cam shows strong flickering but rules out deep eclipses. Although dwarf novae in this period range generally show the superhumps and superoutbursts characteristic of the SU UMa subclass of dwarf novae, none of these objects have well-observed superhumps.
The American Dutch, their church, and the revolution
J. Tanis
BMGN : Low Countries Historical Review , 1982,
Effective equidistribution for some unipotent flows in PSL(2, R)^k mod cocompact, irreducible lattice
James Tanis
Mathematics , 2014,
Abstract: Let $k \geq 2$, and let $\Gamma \subset \operatorname{PSL}(2, \mathbb{R})^k$ be an irreducible, cocompact lattice. We prove effective equidistribution for coordinate horocycle flows on $\Gamma \backslash \operatorname{PSL}(2, \mathbb{R})^k$. This is the simplest case for proving effective equidistribution of unipotent flows in this setting. The main ingredients are Flaminio-Forni's study of the equidistribution of the horocycle flow and a result by Kelmer-Sarnak on the strong spectral gap property of $\Gamma$ in $\operatorname{PSL}(2, \mathbb{R})^k$.
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