847 resultados para Weight locus of control
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Primary control is defined as changing the world to fit the self, while secondary control is defined as changing the self to fit the world. To understand why different individuals prefer different kinds of control processes, we proposed a research project looking at US, German and Indian young adults. We hypothesize that theories of self and the world (fixed vs. malleable; Dweck, 1999) affect the prevailing mode of control used. Furthermore, adolescents’ cultural background is assumed to affect their self-world theories as well as the adaptiveness of specific modes of control. For example, in the US, where the self is tended to be seen as fixed and the world as malleable, primary control prevails and is more adaptive than secondary control while the reverse is expected for India. We present the theoretical outline and methodology of the study as well as first results.
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Two studies investigated differences in the relationships between adolescents' fruit and vegetable intake (FVI) and the predictors specified in the Health Action Process Approach and Social-Cognitive Theory. Retrospective (Study 1; N = 502) and prospective (Study 2; N = 668) designs were applied. Among adolescents with overweight/obesity, intention was cross-sectionally associated with FVI (Study 1); no social or cognitive predictors explained FVI at 14-month follow-up (Study 2). The planning - FVI and self-efficacy - FVI relationships were stronger among adolescents who reduced their body weight to normal, compared to effects observed among those who maintained their body weight (Studies 1 and 2).
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Many of the tumorigenic effects that result from neonatal exposure to both natural and synthetic estrogens resemble those found in humans exposed to diethylstilbestrol (DES) in utero. Using this established DES neonatal mouse model, my goal was to investigate long-term molecular and morphological effects of certain polychlorinated biphenyls (PCBs) that are weakly estrogenic in adult mice. Focusing on the cervicovaginal (CV) tract, since this is where tumors develop in the BALB/c mouse, I first assessed the 17β-estradiol (E2) dose-response for expression of lactoferrin (LTF). LTF is a highly inducible estrogen biomarker that is permanently altered in uteri from neonatally treated mice. Treatments were administered via 5 subcutaneous injections beginning within 16 hrs after birth, days 1–5. ^ The ontogeny of LTF expression from mouse CV tracts was determined by examining three different stages of life: pups, immature, and mature mice. Northern RNA analysis and immunohistochemistry showed that neonatal E 2 treatment both increases and decreases LTF expression. Early expression of LTF in the CV tract at all doses occurred in pups. In both immature and adult mice, increased LTF expression was dependent on whether E2 induced ovary-dependent or ovary-independent persistent vaginal cornification. ^ Next, I studied biological responses from neonatally PCB exposed adult mice. As expected, using a neonatal uterine bioassay I showed that 2 ′4′6′-trichloro-4-biphenylol (OH-PCB-30), 2′3′4′ 5-tetrachloro-4-biphenyloI (OH-PCB-61), and OH-PCB-30/61 (50/50 mixture), were estrogenic causing a dose-dependent increase in uterine weight. ^ Long-term effects of OH-PCB 30 [200 μg/pup/day] were most similar to E2 as seen by an increased uterine wet weight in day 50 mice similar to E2 [5 μg/pup/day] (141% and 140% of control, respectively). Another similarity between OH-PCB 30 and E2 neonatally treated mice was found in those sacrificed at 20 months of age. At these same doses CV tract squamous cell carcinoma induction was 43% of E2 treated mice and 47% of OH-PCB 30 treated mice. Differences were noted in adenoaquamous; cell carcinoma development, where 16% of OH-PCB-30 neonatally treated mice developed tumors versus 8% for E2. Based on these results using the neonatal mouse model, I conclude that the OH-PCBs tested are strongly estrogenic and tumorigenic showing dose-response relationships when exposure occurs during development of the reproductive tract in mice. These results may have important implications for risk assessment in determining the effects of xenoestrogens exposure early versus later in life. ^
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A historical prospective study was designed to assess the man weight status of subjects who participated in a behavioral weight reduction program in 1983 and to determine whether there was an association between the dependent variable weight change and any of 31 independent variables after a 2 year follow-up period. Data was obtained by abstracting the subjects records and from a follow-up questionnaire administered 2 years following program participation. Five hundred nine subjects (386 females and 123 males) of 1460 subjects who participated in the program, completed and returned the questionnaire. Results showed that mean weight was significantly different (p < 0.001) between the measurement at baseline and after a 2 year follow-up period. The mean weight loss of the group was 5.8 pounds, 10.7 pounds for males and 4.2 pounds for females after a 2 year follow-up period. A total of 63.9% of the group, 69.9% of males and 61.9% of females were still below their initial weight after the 2 year follow-up period. Sixteen of the 31 variables assessed utilizing bivariate analyses were found to be significantly (p (LESSTHEQ) 0.05) associated with weight change after a 2 year follow-up period. These variables were then entered into a multivariate linear regression model. A total of 37.9% of the variance of the dependent variable, weight change, was accounted for by all 16 variables. Eight of these variables were found to be significantly (p (LESSTHEQ) 0.05) predictive of weight change in the stepwise multivariate process accounting for 37.1% of the variance. These variables included: Two baseline variables (percent over ideal body weight at enrollment and occupation) and six follow-up variables (feeling in control of eating habits, percent of body weight lost during treatment, frequency of weight measurement, physical activity, eating in response to emotions, and number of pounds of weight gain needed to resume a diet). It was concluded that a greater amount of emphasis should be placed on the six follow-up variables by clinicians involved in the treatment of obesity, and by the subjects themselves to enhance their chances of success at long-term weight loss. ^
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In this book, an international group of leading scientists present perspectives on the control of human behavior, awareness, consciousness, and the meaning and function of perceived control or self-efficacy in people's lives. The book breaks down the barriers between subdisciplines, and thus constitutes an occasion to reflect on various facets of control in human life. Each expert reviews his or her field through the lens of perceived control and shows how these insights can be applied in practice.
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Fasting dogs do transport vitamin A (VA) in plasma not only as retinol but predominantly as retinyl esters. Contrary to retinol, nothing is known concerning the effects of athletic performance on plasma retinyl ester concentrations. The aim of this study was therefore to examine whether physical stress because of exercise and modification of the oxidative stress by supplementation of alpha-tocopherol influences the concentrations of retinol and retinyl esters in plasma of sled dogs. The study was carried out on 41 trained adult sled dogs, which were randomly assigned into two groups. One group (19 dogs) was daily substituted with 50 mg dl-alpha-tocopheryl acetate per kilogram body weight and the control group (22 dogs) was maintained on a basal diet during 3 months prior to exercise. The plasma concentrations of retinol, retinyl esters, alpha-tocopherol and triglycerides were measured immediately before, directly after and 24 h after exercise. The supplementation of alpha-tocopheryl acetate had no effect on plasma retinol and retinyl ester concentrations at any measurement time point. However, retinyl ester levels doubled in the non-supplemented group immediately after the race (p < 0.001), whereas in the supplemented group similar high levels were observed not until 24 h post-racing (p < 0.001). The high levels of retinyl esters were paralleled to some extent by an increase in plasma triglyceride concentrations, which were significantly higher 24 h post-racing than immediately before (p < 0.001) and after exercise (p < 0.001) in both groups. The increase in retinyl ester concentrations might be indicative of their mobilization from liver and adipose tissue. Whether plasma retinyl esters can be used as an indicator for the extent of nutrient mobilization during and post-exercise in sled dogs remains to be elucidated.
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AIM To systematically assess the efficacy of patient-administered mechanical and/or chemical plaque control protocols in the management of peri-implant mucositis (PM). MATERIAL AND METHODS Randomized (RCTs) and Controlled Clinical Trials (CCTs) were identified through an electronic search of three databases complemented by manual search. Identification, screening, eligibility and inclusion of studies was performed independently by two reviewers. Studies without professional intervention or with only mechanical debridement professionally administered were included. Quality assessment was performed by means of the Cochrane Collaboration's tool for assessing risk of bias. RESULTS Eleven RCTs with a follow-up from 3 to 24 months were included. Definition of PM was lacking or heterogeneously reported. Complete resolution of PM was not achieved in any study. One study reported 38% of patients with complete resolution of PM. Surrogate end-point outcomes of PM therapy were often reported. The choice of control interventions showed great variability. The efficacy of powered toothbrushes, a triclosan-containing toothpaste and adjunctive antiseptics remains to be established. High quality of methods and reporting was found in four studies. CONCLUSIONS Professionally- and patient-administered mechanical plaque control alone should be considered the standard of care in the management of PM. Therapy of PM is a prerequisite for the prevention of peri-implantitis.
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A CDP-diacylglycerol dependent phosphatidylserine synthase was detected in three species of gram-positive bacilli, viz. Bacillus licheniformis, Bacillus subtilis and Bacillus megaterium; the enzyme in B. licheniformis was studied in detail. The subcellular distribution experiments in cell-free extracts of B. licheniformis using differential centrifugation, sucrose gradient centrifugation and detergent solubilization showed the phosphatidylserine synthase to be tightly associated with the membrane. The enzyme was shown to have an absolute requirement for divalent metal ion for activity with a strong preference for manganese. The enzyme activity was completely dependent upon the addition of CDP-diacylglycerol to the assay system; the role of the liponucleotide was rigorously shown to be that of phosphatidyl donor and not just a detergent-like stimulator. This enzyme was then solubilized from B. licheniformis membranes and purified to near homogeneity. The purification procedure consisted of CDP-diacylglycerol-Sepharose affinity chromatography followed by substrate elution from blue-dextran Sepharose. The purified preparation showed a single band with an apparent minimum molecular weight of 53,000 when subjected to SDS polyacrylamide gel electrophoresis. The preparation was free of any phosphatidylglycerophosphate synthase, CDP-diacylglycerol hydrolase and phosphatidylserine hydrolase activities. The utilization of substrates and formation of products occurred with the expected stoichiometry. Radioisotopic exchange patterns between related substrate and product pairs suggest a sequential BiBi reaction as opposed to the ping-pong mechanism exhibited by the well studied phosphatidylserine synthase of Escherichia coli. Proteolytic digestion of the enzyme yielded a smaller active form of the enzyme (41,000 daltons) which appears to be less prone to aggregation.^ This has been the first detailed study in a well-defined bacillus species of the enzyme catalyzing the CDP-diacylglycerol-dependent formation of phosphatidylserine; this reaction is the first committed step in the biosynthetic pathway to the major membrane component, phosphatidylethanolamine. Further study of this enzyme may lead to understanding of new mechanisms of phosphatidyl transfer and novel modes of control of phospholipid biosynthetic enzymes. ^
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This descriptive systematic review describes intervention trials for children and youth that targeted screen time (ST) as a way to prevent or control obesity and measured ST, and at least one of the following: physical activity, dietary intake, and adiposity. Both “hands-on” (e.g., video games) and “hands free” (e.g., television viewing) ST were included. Published, completed intervention trials (k=12), not-yet-published, completed trials (k=6), and in-progress trials (k=11) were identified through searches of electronic databases, including trial registries and bibliographies of eligible study reports. Study characteristics of the 29 identified trials were coded and presented in evidence tables. Considerable attention was paid to the type of ST addressed, measures used, and the type of interventions. Based on the number of in-progress and not-yet-published trials, the number of completed, published reports will double in the next three years. Most of the studies were funded by federal sources. General populations, not restricted by race, gender, or weight status, were targets of most interventions with children ages 9-12 yeas as the modal age group. Most trials used randomized control trials in which the majority of control or comparison group received an intervention. The mean number of participants was 242.8 (SD=314.7) and interventions were delivered over an average of 10.5 months and consisted of approximately 16 sessions, with a total time of about eight hours. The majority of completed trials evaluate each of the four constructs, however, most studies have more than one measure to assess each construct (e.g., BMI and tricep skinfold thickness to evaluate adiposity) and rarely did studies use the same measures. This is likely why the majority of studies produced at least one significant intervention effect on each outcome that was assessed. The four major outcomes should be evaluated in all interventions attempting to reduce screen time in order to determine the mechanisms involved that may contribute to obesity. More importantly researchers should work together to determine the best measures to evaluate the four main constructs to allow studies to be compared. Another area for consensus is the definition of ST. ^
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Maternal use of SSRIs for depression and anxiety during pregnancy has increased over the last decade. Recent studies have questioned the safety of these antidepressants when used in during pregnancy. The aim of this project is to assess the associations between maternal SSRI use and GH, SGA, and preterm birth using data from a U.S. population-based study with self-reported exposure information. ^ The study population is comprised of mothers of control infants from the NBDPS, an ongoing, multi-state, population-based case-control study. Mothers were asked about any use of medications during pregnancy, including the dates they started and stopped taking each medication. Maternal GH was self-reported, while gestational age and birth weight were calculated from information on birth certificates or medical records. ^ Our study found that women exposed to SSRIs in the first trimester and beyond had a higher odds of GH compared to unexposed women (aOR=1.96, 95% CI=1.02-3.74). Women who used SSRIs only in the first trimester had no increased odds of GH (aOR=0.77, 95% CI=0.24-2.50). Women who used SSRIs throughout their entire pregnancy had a two-fold increase in the odds of delivering an SGA infant compared to unexposed women (aOR=2.16, 95% CI=1.01-4.62), while women who reported SSRI use only in the first trimester had a decreased odds of delivering an SGA infant (aOR=0.56, 95% CI=0.14-2.34). Finally, both women who used SSRIs in the first trimester only (aOR=1.58, 95% CI=0.71-3.51) and women who used SSRIs in the first trimester and beyond (aOR=1.49, 95% CI=0.76-2.90) had an increased odds of delivering preterm compared to unexposed women. ^ Results from our study suggest that women who use SSRIs in the first trimester and beyond have an increased and significant odds of GH and SGA. An increase in the odds of preterm birth was also observed among women exposed in this period and is consistent with the results of previous studies which had much larger sample sizes. Women who use SSRIs only in the first trimester appear to have no increased odds of GH or SGA, but may have an increased odds of preterm birth. These findings are consistent with previous studies and highlight how exposure to SSRIs at different points in gestation may result in different risks for these outcomes. ^
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Problem. Recent statistics show that over a fifth of children aged 2-5 years in 2006-2008 were overweight, with 7% above the 97 th percentile of the BMI-for-age growth charts (extreme obesity). Because poor diet is an important environmental determinant of obesity and the preschool years are crucial developmentally, examination of factors related to diet in the pre-school years is important for obesity prevention efforts. ^ Objective. The goals of this study were to determine the association between BMI of the parents and the number of servings of fruits, vegetables, and whole grains (FVWG) packed; the nutrient content of preschool children’s lunches; and norms and expectations about FVWG intake.^ Methods. This study was a cross sectional analysis of parents enrolled in the Lunch is in the Bag program at baseline. The independent measure was weight status of the parents/caregivers, which was determined using body mass index (BMI) calculated from self-reported height and weight. BMI was classified as healthy weight (BMI <25) or overweight/obese (BMI ≥25). Outcomes for the study included the number of servings of fruits, vegetables and whole grains (FVWG) in sack lunches, as well as the nutrient content of the lunches, and psychosocial constructs related to FVWG consumption. Linear regression analysis was conducted and adjusted for confounders to examine the associations of these outcomes with parental weight status, the main predictor. ^ Results. A total of 132 parent/child dyads were enrolled in the study; 59.09% (n=78) of the parents/caregivers were healthy weight and 39.01% (n=54) of the parents/caregivers were overweight/obese. Parents/caregivers in the study were predominantly white (68%, n=87) and had at least some college education (98%, n=128). No significant associations were found between the weight status of the parents and the servings of fruits, vegetables and whole grain packed in preschool children’s lunchboxes. The results were similar for the association of parental weight status and the nutrient contents of the packed lunches. Both healthy weight and overweight/obese parents packed less than the recommended amounts of vegetables (mean servings = 0.49 and 0.534, respectively) and whole grains (mean servings = 0.58 and 0.511, respectively). However, the intentions of the obese/overweight parents were higher compare to the healthy for vegetables and whole grains.^ Conclusion. Results from this study indicate that there are few differences in the servings of fruits, vegetables and whole grains packed by healthy weight parents/caregivers compared to overweight/obese parents/caregivers in a high income, well-educated population, although neither group met the recommended number of servings of vegetables or whole grains. Thus, results indicate the need for behaviorally-based health promotion programs for parents, regardless of their weight status; however, this study should be replicated with larger and more diverse populations to determine if these results are similar with less homogenous populations.^
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The hypothesis that large fluctuations in weight during young adulthood are associated with the degree of coronary artery disease was investigated by comparing patterns of weight change of patients with angiographically defined diseased or normal arteries. Participants (n = 823) were selected from men and women aged 40-74 years who had undergone angiography at North Carolina Baptist Hospital during 1987-88. Weight history from age 20 to 40 was assessed with a mailed questionnaire. Per cent prevalence of "yo-yo dieting" adjusted for age, race, and coronary disease risk factors in patients who had 0, 1, 2, 3, or more than 3 diseased arteries was 8.6, 8.8, 3.7, 5.6 and 7.1 per cent respectively (p = 0.313). These results do not support the research hypothesis. However, since the results may have been confound by neuroticism, they should not be interpreted as strong evidence against this hypothesis. ^
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Like other simple retroviruses the murine sarcoma virus ts110 (MuSVts110) displays an inefficient mode of genome splicing. But, unlike the splicing phenotypic of other retroviruses, the splicing event effected upon the transcript of MuSVts110 is temperature sensitive. Previous work in this laboratory has established that the conditionally defective nature of MuSVts110 RNA splicing is mediated in cis by features in the viral transcript. Here we show that the 5$\sp\prime$ splice site of the MuSVts110 transcript acts as a point of control of the overall splicing efficiency at both permissive and nonpermissive temperatures for splicing. We strengthened and simultaneously weakened the nucleotide structure of the 5$\sp\prime$ splice site in an attempt to elucidate the differential effects each of the two known critical splicing components which interact with the 5$\sp\prime$ splice site have on the overall efficiency of intron excision. We found that a transversion of the sixth nucleotide, resulting in the formation of a near-consensus 5$\sp\prime$ splice site, dramatically increased the overall efficiency of MuSVts110 RNA splicing and abrogated the thermosensitive nature of this splicing event. Various secondary mutations within this original transversion mutant, designed to selectively decrease specific splicing component interactions, lead to recovery of inefficient and thermosensitive splicing. We have further shown that a sequence of 415 nucleotides lying in the downstream exon of the viral RNA and hypothesized to act as an element in the temperature-dependent inhibition of splicing displays a functional redundancy throughout its length; loss and/or replacement of any one sequence of 100 nucleotides within this sequence does not, with one exception detailed below, diminish the degree to which MuSVts110 RNA is inhibited to splice at the restrictive temperature. One specific deletion, though, fortuitously juxtaposed and activated cryptic consensus splicing signals for the excision of a cryptic intron within the downstream exon and markedly potentiated--across a newly defined cryptic exon--the splicing event effected upon the upstream, native intron. We have exploited this mutant of MuSVts110 to further an understanding of the process of exon definition and intron definition and show that the polypyrimidine tract and consensus 3$\sp\prime$ splice site, as well as the 5$\sp\prime$ splice site, within the intron at the 3$\sp\prime$ flank of the defined exon are required for the exon's definition; implying that definition of the downstream intron is required for the in vivo definition of the proximal, upstream exon. Finally; we have shown, through the construction of heterologous mutants of MuSVts110 employing a foreign 3$\sp\prime$ end-forming sequence, that efficiency of transcript splicing can be increased--to a degree which abrogates its thermosensitive nature--in direct proportion to increasing proximity of the 3$\sp\prime$ end-forming signal to the terminal 3$\sp\prime$ splice site. ^
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Antarctic terrestrial ecosystems have poorly developed soils and currently experience one of the greatest rates of climate warming on the globe. We investigated the responsiveness of organic matter decomposition in Maritime Antarctic terrestrial ecosystems to climate change, using two study sites in the Antarctic Peninsula region (Anchorage Island, 67°S; Signy Island, 61°S), and contrasted the responses found with those at the cool temperate Falkland Islands (52°S). Our approach consisted of two complementary methods: (1) Laboratory measurements of decomposition at different temperatures (2, 6 and 10 °C) of plant material and soil organic matter from all three locations. (2) Field measurements at all three locations on the decomposition of soil organic matter, plant material and cellulose, both under natural conditions and under experimental warming (about 0.8 °C) achieved using open top chambers. Higher temperatures led to higher organic matter breakdown in the laboratory studies, indicating that decomposition in Maritime Antarctic terrestrial ecosystems is likely to increase with increasing soil temperatures. However, both laboratory and field studies showed that decomposition was more strongly influenced by local substratum characteristics (especially soil N availability) and plant functional type composition than by large-scale temperature differences. The very small responsiveness of organic matter decomposition in the field (experimental temperature increase <1 °C) compared with the laboratory (experimental increases of 4 or 8 °C) shows that substantial warming is required before significant effects can be detected.
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This paper proposes a novel robotic system that is able to move along the outside of the oil pipelines used in Electric Submersible Pumps (ESP) and Progressive Cavity Pumps (PCP) applications. This novel design, called RETOV, proposes a light weight structure robot that can be equipped with sensors to measure environmental variables avoiding damage in pumps and wells. In this paper, the main considerations and methodology of design and implementation are discussed. Finally, the first experimental results that show RETOV moving in vertical pipelines are analyzed.