984 resultados para graded-index fiber lens


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OBJECTIVE: Body mass index does not discriminate body fat from fat-free mass or determine changes in these parameters with physical activity and aging. Body fat mass index (BFMI) and fat-free mass index (FFMI) permit comparisons of subjects with different heights. This study evaluated differences in body mass index, BFMI, and FFMI in physically active and sedentary subjects younger and older than 60 y and determined the association between physical activity, age, and body composition parameters in a healthy white population between ages 18 and 98 y. METHODS: Body fat and fat-free mass were determined in healthy white men (n = 3549) and women (n = 3184), between ages 18 and 98 y, by bioelectrical impedance analysis. BFMI and FFMI (kg/m2) were calculated. Physical activity was defined as at least 3 h/wk of endurance-type activity for at least 2 mo. RESULTS: Physically active as opposed to sedentary subjects were more likely to have a low BFMI (men: odds ratio [OR], 1.4; confidence interval [CI], 0.7-2.5; women: OR 1.9, CI 1.6-2.2) and less likely to have very high BFMI (men: OR, 0.2; CI, 0.1-0.2; women: OR, 0.1; CI, 0.02-0.2), low FFMI (men: OR, 0.5; CI, 0.3-0.9; women: OR, 0.7; CI, 0.6-0.9), or very high FFMI (men: OR, 0.6; CI, 0.4-0.8; women: OR, 0.7; CI, 0.5-1.0). Compared with subjects younger than 60 y, those older than 60 y were more like to have very high BFMI (men: OR, 6.5; CI, 4.5-9.3; women: OR, 14.0; CI, 9.6-20.5), and women 60 y and older were less likely to have a low BFMI (OR, 0.4; CI, 0.2-0.5). CONCLUSIONS: A clear association was found between low physical activity or age and height-normalized body composition parameters (BFMI and FFMI) derived from bioelectrical impedance analysis. Physically active subjects were more likely to have high or very high or low FFMI. Older subjects had higher body weights and BFMI.

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Markets, in the real world, are not efficient zero-sum games where hypotheses of the CAPM are fulfilled. Then, it is easy to conclude the market portfolio is not located on Markowitz"s efficient frontier, and passive investments (and indexing) are not optimal but biased. In this paper, we define and analyze biases suffered by passive investors: the sample, construction, efficiency and active biases and tracking error are presented. We propose Minimum Risk Indices (MRI) as an alternative to deal with to market index biases, and to provide investors with portfolios closer to the efficient frontier, that is, more optimal investment possibilities. MRI (using a Parametric Value-at-Risk Minimization approach) are calculated for three stock markets achieving interesting results. Our indices are less risky and more profitable than current Market Indices in the Argentinean and Spanish markets, facing that way the Efficient Market Hypothesis. Two innovations must be outlined: an error dimension has been included in the backtesting and the Sharpe"s Ratio has been used to select the"best" MRI

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Benthic macroinvertebrate assemblages do not appear to differ as markedly between coldwater and warmwater streams (in Iowa, at least) as do fish assemblages, and to our knowledge no parallel evaluation of benthic macroinvertebrate communities in coldwater streams has been conducted. What is known is that many taxa are exclusively collected in coldwater environments and are considered “rare” in Iowa from a biogeographical perspective. While the warmwater BMIBI has generally proven to work well as a diagnostic tool for Iowa’s streams, the streams of Iowa’s Paleozoic Plateau tend to group in the “excellent” to “good” qualitative rating categories. The streams of this area tend to be more ecologically intact than other areas of the state; however, there are some artifacts of the current warmwater BMIBI (most specifically metric scoring related to watershed size) that skew IBI values higher. Our objective is to develop a Coldwater Benthic Index (CBI) which will provide a more accurate assessment of streams classified, or potentially classifiable, as coldwater.

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BACKGROUND: Head and neck cancer (HNC) risk is elevated among lean people and reduced among overweight or obese people in some studies; however, it is unknown whether these associations differ for certain subgroups or are influenced by residual confounding from the effects of alcohol and tobacco use or by other sources of biases. METHODS: We pooled data from 17 case-control studies including 12 716 cases and the 17 438 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for associations between body mass index (BMI) at different ages and HNC risk, adjusted for age, sex, centre, race, education, tobacco smoking and alcohol consumption. RESULTS: Adjusted ORs (95% CIs) were elevated for people with BMI at reference (date of diagnosis for cases and date of selection for controls) 25.0-30.0 kg/m(2) (0.52, 0.44-0.60) and BMI >/=30 kg/m(2) (0.43, 0.33-0.57), compared with BMI >18.5-25.0 kg/m(2). These associations did not differ by age, sex, tumour site or control source. Although the increased risk among people with BMI 25 kg/m(2) was present only in smokers and drinkers. CONCLUSIONS: In our large pooled analysis, leanness was associated with increased HNC risk regardless of smoking and drinking status, although reverse causality cannot be excluded. The reduced risk among overweight or obese people may indicate body size is a modifier of the risk associated with smoking and drinking. Further clarification may be provided by analyses of prospective cohort and mechanistic studies.

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AIM: The resting metabolic rate (RMR) varies among pregnant women. The factors responsible for this variability are unknown. This study aimed to assess the influence of the prepregnancy body mass index (BMI) on the RMR during late pregnancy. METHODS: RMR, height, weight, and total (TEE) and activity (AEE) energy expenditures were measured in 46 healthy women aged 31 ± 5 years (mean ± SD) with low (<19.8), normal (19.8-26.0), and high (>26.0) prepregnancy BMI at 38.2 ± 1.5 weeks of gestation (t(gest)) and 40 ± 7 weeks postpartum (t(post)) (n = 27). RESULTS: The mean t(gest) RMR for the low-, normal-, and high-BMI groups was 1,373, 1,807, and 2,191 kcal/day, respectively (p = 0.001). The overall mean t(gest) RMR was 316 ± 183 kcal/day (21%), higher than the overall mean t(post) value and this difference was correlated with gestational weight gain (r = 0.78, p < 0.001). The scaled metabolic rate by allometry (RMR/kilograms⁰·⁷³) was similar in the low-, normal-, and high-BMI groups, respectively (p = 0.45). Changes in t(gest) TEE closely paralleled changes in t(gest) RMR (r = 0.84, p < 0.001). AEE was similar among the BMI groups. CONCLUSION: The RMR is significantly increased in the third trimester of pregnancy. The absolute gestational RMR is higher in women with high prepregnancy BMI due to increased body weight. The scaled metabolic rate (RMR/kilograms⁰·⁷³) is similar among the BMI groups of pregnant women.

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Obesity is globally prevalent and highly heritable, but its underlying genetic factors remain largely elusive. To identify genetic loci for obesity susceptibility, we examined associations between body mass index and ∼ 2.8 million SNPs in up to 123,865 individuals with targeted follow up of 42 SNPs in up to 125,931 additional individuals. We confirmed 14 known obesity susceptibility loci and identified 18 new loci associated with body mass index (P < 5 × 10⁻⁸), one of which includes a copy number variant near GPRC5B. Some loci (at MC4R, POMC, SH2B1 and BDNF) map near key hypothalamic regulators of energy balance, and one of these loci is near GIPR, an incretin receptor. Furthermore, genes in other newly associated loci may provide new insights into human body weight regulation.

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Obesity is heritable and predisposes to many diseases. To understand the genetic basis of obesity better, here we conduct a genome-wide association study and Metabochip meta-analysis of body mass index (BMI), a measure commonly used to define obesity and assess adiposity, in up to 339,224 individuals. This analysis identifies 97 BMI-associated loci (P < 5 × 10(-8)), 56 of which are novel. Five loci demonstrate clear evidence of several independent association signals, and many loci have significant effects on other metabolic phenotypes. The 97 loci account for ∼2.7% of BMI variation, and genome-wide estimates suggest that common variation accounts for >20% of BMI variation. Pathway analyses provide strong support for a role of the central nervous system in obesity susceptibility and implicate new genes and pathways, including those related to synaptic function, glutamate signalling, insulin secretion/action, energy metabolism, lipid biology and adipogenesis.

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RésuméLe PESI (Pulmonary Embolism Severity Index) est un score clinique pronostique s'appliquant à des patients présentant un diagnostic d'embolie pulmonaire. Notre objectif était de démontrer la reproductibilité de ce score entre différents médecins chez des patients présentant une embolie pulmonaire. Nous avons donc identifié, de façon prospective, des patients présentant une embolie pulmonaire nouvellement diagnostiquée aux urgences d'un Hôpital Universitaire (CHUV, Lausanne). Pour tous ces patients, le médecin assistant en charge ainsi que le chef de clinique superviseur ont individuellement collecté les différentes variables permettant d'établir le score selon le PESI. Ils ont, ensuite, de façon indépendante, classifié les patients dans 5 classes de risque (1-V) ainsi qu'en deux groupes à bas risque versus haut risque, respectivement les classes i-ll et les classes III à V.Nous avons examiné la reproductibilité des données entre deux groupes de médecins (médecins assistants vs chefs de clinique), pour chacune des variables constituant le PESI, pour le score total en points, pour l'attribution aux 5 classes de risque ainsi que pour la classification en deux groupes à haut risque versus bas risque. Cette évaluation de la reproductibilité des résultats obtenus par les différents médecins s'est basée sur le calcul du Kappa (K) ainsi sur les Coefficients de Corrélation Intra-classe (ICC).Parmi les 48 patients présentant une Embolie Pulmonaire inclus dans notre étude, les coefficients de reproductibilité entre médecins assistants et chefs de clinique étaient supérieurs à 0.60 pour 10 des 11 variables du PESI. La reproductibilité entre les 2 groupes de médecins, pour le total des points, pour l'attribution à une classe de risque I à V, ainsi que pour la classification en bas versus haut risque était presque parfaite.Nos résultats démontrent la haute reproductibilité du PESI, et appuient donc l'intérêt de son utilisation pour la stratification du risque chez des patients présentant une embolie pulmonaire.

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Background and Aims: Eosinophilic Esophagitis (EoE) is reported with increasing frequency over the last two decades. However, it is still unknown whether this reflects a true increase in incidence or just an increased awareness by gastroenterologists. Therefore, we evaluated the incidence and cumulative prevalence of EoE in Olten county over the last 20 years. Methods: Olten county is an area of approximately 91,000 inhabitants without pronounced demographic changes in the last two decades. EoE evaluation is based upon two gastroenterology centers and one pathology center. No public programs for increased EoE awareness were implemented in this region. All EoE patients diagnosed from 1989 to 2009 were entered prospectively into the Olten county database. Results: Fourty-six patients (76% males, mean age 41±16 yrs) were diagnosed with EoE from 1989 to 2009. Ninety-four percent presented with dysphagia. In 70% of the patients concomitant allergies were found. The number of upper endoscopies per year was stable during the entire observation period. An average annual incidence rate of 2/100,000 was found (range 0-8) with a marked increase in the period from 2001 to 2009. A current cumulative EoE prevalence of 43/100,000 inhabitants was calculated. The mean diagnostic delay (time from first symptoms to diagnosis) was 4.3 years from 1989 to 1998 and 4.8 years from 1999 to 2009. Conclusions: Over the last 20 years, a significant increase in EoE incidence was found in a stable indicator region of Switzerland. The constant rate of upper endoscopies, the constant diagnostic delay, as well as the lack of EoE awareness programs in Olten county indicate a true increase in EoE incidence.

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Sellun kuivatuksesta ei löydy paljoa tutkimustietoa. Työn tarkoituksena on antaa lyhyt teoriakuvaus sellun kuivatuksesta, kuivatukseen vaikuttavista tekijöistä jasellun kuivatuksen vaikutuksesta sellun laatuun. Käytännön osassa tutkittiin kuivauskoneen poikkiradan hienoainepitoisuuden ja vetolujuussuhteiden vaihtelua, suihkusuhteiden, kenkäpuristimen viivakuorman sekä paalipuristimen puristusvoimanvaikutusta sellun paperiteknisiin ominaisuuksiin. Sellun kuivauskone koostuu perälaatikosta, viiraosasta, puristinosasta sekä kuivausosasta.Perälaatikon tehtävä on syöttää massa tasaisesti viiraosalle. Viiraosalla poistuu suurin osa vedestä (noin 94 %) ja viiraosalla tapahtuu pohjan muodostus. Tässä työssä tutkittu suihkusuhde on yksi rainan muodostukseen vaikuttava tekijä. Puristinosalla voidaan sellun ominaisuuksiin vaikuttaa puristuksen voimalla ja kestolla ja tätä työssä tutkittiin kenkäpuristimen viivakuormaa muuttamalla. Varsinainen kuivatus voi tapahtua joko kuumia sylinteripintoja tai ilmaa hyödyntäen. Kuivauskoneen jälkeen on leikkuri, paalauspöytä ja paalipuristin. Paalipuristuksen vaikutusta sellun ominaisuuksiin tutkittiin keventämällä paalipuristusta nykyisestä.

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Common variants at only two loci, FTO and MC4R, have been reproducibly associated with body mass index (BMI) in humans. To identify additional loci, we conducted meta-analysis of 15 genome-wide association studies for BMI (n > 32,000) and followed up top signals in 14 additional cohorts (n > 59,000). We strongly confirm FTO and MC4R and identify six additional loci (P < 5 x 10(-8)): TMEM18, KCTD15, GNPDA2, SH2B1, MTCH2 and NEGR1 (where a 45-kb deletion polymorphism is a candidate causal variant). Several of the likely causal genes are highly expressed or known to act in the central nervous system (CNS), emphasizing, as in rare monogenic forms of obesity, the role of the CNS in predisposition to obesity.

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PURPOSE: To localize collagen types I, III, and IV, laminin and fibronectin in the anterior human lens capsule. MATERIAL AND METHODS: Twenty-one anterior capsules were sampled by capsulorhexis during extracapsular cataract extraction (mean age 71.5). All capsules were labelled by an immunostaining specific for each antibodies. Immunostaining of four capsules was revealed with immunoperoxydase and seventeen using indirect immunofluorescence. RESULTS: Labelling of collagen types I and III was observed throughout the entire thickness of the capsule for each technique, the strongest labelling was found in the base of the epithelial cells with immunofluorescence. Collagen type IV was observed at the base of the epithelial cells whichever technique was used. Laminin could be detected in the inner layer of the capsule, using immunoperoxydase or immunofluorescence. No specific labelling was found for fibronectin using the two techniques. CONCLUSIONS: Different kinds of collagens have been found in capsules, more particularly the type III. The latter does not appear on other ocular basement membrane. Because of this uneven distribution in the capsule's thickness, each collagen might have a specific function.