223 research outputs found
Association of glycosylated hemoglobin (HbA1c) levels with Iinsulin resistance in obese children.
Objectives: We investigated the relationship between insulin resistance reflected by homeostasis model assessment (HOMA-IR) index and serum HbA1c levels of obese children.Material and Methods: This study included 70 obese and 60 normal weight healthy children between the ages of 3 and 15. Anthropometric measures and biochemical tests (fasting glucose, fasting insulin, HbA1c) were performed on all subjects. Plasma glucose levels were measured by the glucose oxidase method. Plasma insulin concentrations were measured by radioimmunoassay (RIA). HOMA-IR index was used to estimate insulin resistance. A cut-off HOMA-IR level of ≥2.5 was accepted. The HbA1c analysis was performed using high-pressure liquid chromatography. The statistical analysis was performed using SPSS 5. Student’s unpaired t-test and the Mann–Whitney U test were used to determine statistical significance.Results: Gender distribution did not reveal significant difference among the obese (F: 48.6%, M: 51.4%) and the non-obese (F: 46.7%, M: 53.3%) groups. The mean age value was significantly higher in the obese group (10.09± 3.09) (p>0.005) than the non-obese group (8.31±3.14) (p<0.05). The mean value of body mass index (BMI) was 25.55±4.3 in the obese group and 16.63±2.3 in the non-obese group. The mean HOMA-IR values of obese group (2.84±1.77) was significantly higher than the non-obese group (1.50±0.95) (p<0.005). Insulin resistance was significantly higher in the obese group. Subjects with HOMA-IR ≥2.5 levels in the obese group had significantly higher HbA1c values than those with HOMA-IR <2.5 levels.Conclusions: High HbA1c levels in obese children can be used as a screening tool to detect insulin sensitivity and resistance at an early stage.Key words: children, HbA1c protein, insulin resistance, obesity
Characterization of an embedded RF-MEMS switch
An RF-MEMS capacitive switch for mm-wave integrated circuits, embedded in the BEOL of 0.25μm BiCMOS process, has been characterized. First, a mechanical
model based on Finite-Element-Method (FEM) was developed by taking the residual stress of the thin film membrane into account. The pull-in voltage and the capacitance values obtained with the mechanical model agree very well with the
measured values. Moreover, S-parameters were extracted using Electromagnetic (EM) solver. The data observed in this way also agree well with the experimental ones measured up to 110GHz. The developed RF model was applied to a transmit/receive (T/R) antenna switch design. The results proved the feasibility of using the FEM model in circuit simulations for the development of RF-MEMS switch embedded, single-chip multi-band RF ICs
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Milk fatty acids estimated by mid-infrared spectroscopy and milk yield can predict methane emissions in dairy cows
Ruminant enteric methane emission contributes to global warming. Although breeding low methane-emitting cows appears to be possible through genetic selection, doing so requires methane emission quantification by using elaborate instrumentation (respiration chambers, SF6 technique, GreenFeed) not feasible on a large scale. It has been suggested that milk fatty acids are promising markers of methane production. We hypothesized that methane emission can be predicted from the milk fatty acid concentrations determined by mid-infrared spectroscopy, and the integration of energy-corrected milk yield would improve the prediction. Therefore, we examined relationships between methane emission of cows measured in respiration chambers and milk fatty acids, predicted by mid-infrared spectroscopy, to derive diet-specific and general prediction equations based on milk fatty acid concentrations alone and with the additional consideration of energy-corrected milk yield. Cows were fed diets differing in forage type and linseed supplementation to generate a large variation in both CH4 emission and milk fatty acids. Depending on the diet, equations derived from regression analysis explained 61 to 96% of variation of methane emission, implying the potential of milk fatty acid data predicted by mid-infrared spectroscopy as novel proxy for direct methane emission measurements. When data from all diets were analyzed collectively, the equation with energy-corrected milk yield (CH4 (L/day) = − 1364 + 9.58 × energy-corrected milk yield + 18.5 × saturated fatty acids + 32.4 × C18:0) showed an improved coefficient of determination of cross-validation R2 CV = 0.72 compared to an equation without energy-corrected milk yield (R2 CV = 0.61). Equations developed for diets supplemented by linseed showed a lower R2 CV as compared to diets without linseed (0.39 to 0.58 vs. 0.50 to 0.91). We demonstrate for the first time that milk fatty acid concentrations predicted by mid-infrared spectroscopy together with energy-corrected milk yield can be used to estimate enteric methane emission in dairy cows. © 2018, The Author(s)
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Methane prediction based on individual or groups of milk fatty acids for dairy cows fed rations with or without linseed
Milk fatty acids (MFA) are a proxy for the prediction of CH4 emission from cows, and prediction differs with diet. Our objectives were (1) to compare the effect of diets on the relation between MFA profile and measured CH4 production, (2) to predict CH4 production based on 6 data sets differing in the number and type of MFA, and (3) to test whether additional inclusion of energy-corrected milk (ECM) yield or dry matter intake (DMI) as explanatory variables improves predictions. Twenty dairy cows were used. Four diets were used based on corn silage (CS) or grass silage (GS) without (L0) or with linseed (LS) supplementation. Ten cows were fed CS-L0 and CS-LS and the other 10 cows were fed GS-L0 and GS-LS in random order. In feeding wk 5 of each diet, CH4 production (L/d) was measured in respiration chambers for 48 h and milk was analyzed for MFA concentrations by gas chromatography. Specific CH4 prediction equations were obtained for L0-, LS-, GS-, and CS-based diets and for all 4 diets collectively and validated by an internal cross-validation. Models were developed containing either 43 identified MFA or a reduced set of 7 groups of biochemically related MFA plus C16:0 and C18:0. The CS and LS diets reduced CH4 production compared with GS and L0 diets, respectively. Methane yield (L/kg of DMI) reduction by LS was higher with CS than GS diets. The concentrations of C18:1 trans and n-3 MFA differed among GS and CS diets. The LS diets resulted in a higher proportion of unsaturated MFA at the expense of saturated MFA. When using the data set of 43 individual MFA to predict CH4 production (L/d), the cross-validation coefficient of determination (R2 CV) ranged from 0.47 to 0.92. When using groups of MFA variables, the R2 CV ranged from 0.31 to 0.84. The fit parameters of the latter models were improved by inclusion of ECM or DMI, but not when added to the data set of 43 MFA for all diets pooled. Models based on GS diets always had a lower prediction potential (R2 CV = 0.31 to 0.71) compared with data from CS diets (R2 CV = 0.56 to 0.92). Models based on LS diets produced lower prediction with data sets with reduced MFA variables (R2 CV = 0.62 to 0.68) compared with L0 diets (R2 CV = 0.67 to 0.80). The MFA C18:1 cis-9 and C24:0 and the monounsaturated FA occurred most often in models. In conclusion, models with a reduced number of MFA variables and ECM or DMI are suitable for CH4 prediction, and CH4 prediction equations based on diets containing linseed resulted in lower prediction accuracy. © 2019 American Dairy Science Associatio
Measuring sustainable employability:psychometric properties of the capability set for work questionnaire
BACKGROUND: The capability set for work questionnaire (CSWQ) is being used to measure the new model of sustainable employability building on the capability approach. However, previous studies on the psychometric properties of the instrument are limited and cross-sectional. This two-way study aimed to (1) evaluate the convergent validity of the CSWQ with the theoretically related constructs person-job fit, strengths use, and opportunity to craft and (2) test the predictive and incremental validity of the questionnaire for the well-established work outcomes, including work ability, work engagement, job satisfaction, and task performance. METHODS: A representative sample of 303 Dutch workers, chosen with probably random sampling, were surveyed using a one-month follow-up, cross-lagged design via the Longitudinal Internet Studies for the Social Sciences panel. The convergent validity was assessed by exploring the strength of associations between the capability set for work questionnaire and the theoretically related constructs using Pearson’s correlations. The predictive and incremental validity was evaluated by performing a series of linear hierarchical regression analyses. RESULTS: We found evidence of the convergent validity of the capability set score by moderate correlations with person-job fit, strengths use, and opportunity to craft (r = 0.51–0.52). A series of multiple regression analyses showed that Time 1 capability set score and its constituents (i.e., importance, ability, and enablement) generally had predictive and incremental validity for work ability, work engagement, job satisfaction, and task performance measured at Time 2. However, the incremental power of the CSWQ over and above conceptually related constructs was modest. CONCLUSIONS: The findings support the convergent, predictive, and incremental validity of the capability set for work questionnaire with not previously investigated work constructs. This provided further evidence to support its utility for assessing a worker’s sustainable employability for future research and practical interventions
Expectations of mental illness disclosure outcomes in the work context:A cross-sectional study among Dutch workers
Purpose The decision whether to disclose mental illness at work can have important positive and negative consequences for sustainable employment and well-being. The aim of the study is (1) to examine workers’ expectations of outcomes of mental illness disclosure in the workplace and to evaluate their expectations regarding which factors are of influence on these outcomes, (2) to identify distinct subgroups of workers, and (3) to characterize these subgroups in terms of personal, sociodemographic, and work-related characteristics. Methods In this cross-sectional survey study, a sample of 1224 Dutch workers was used. Latent Class Analysis (LCA) was used to identify classes of workers based on expected workplace mental illness outcomes. A three-step approach LCA was chosen to investigate whether the classes differed in characteristics. Results The majority of workers expected predominantly positive outcomes of workplace mental illness disclosure (e.g., being able to be one’s authentic self; 82.4%), even though they simultaneously expected disclosure to lead to advancement-related discrimination (e.g., lower chances of contract renewal; or getting a promotion; 68.4% and 57%, respectively). Six distinct subgroups of workers were identified based on expected workplace mental illness disclosure outcomes: two positive classes (50.1%), two negative classes (33.3%), and two classes who indicated not to know what the outcomes would be (16.7%). Significant differences between the classes were found on personal experience, work-related association with mental illness, gender, educational level, and workplace atmosphere. Conclusion The disclosure process is complex, as most workers were optimistic (i.e., expected generally positive outcomes) whilst simultaneously expecting workplace discrimination. Subgroup differences in expectations regarding workplace mental illness disclosure outcomes were found
Flight-scheduling optimization and automation for AnadoluJet
AnadoluJet, a leading Turkish domestic airline carrier provides high-service, low-price flights to 28 locations within Turkey. Each winter and summer, AnadoluJet typically generates a new flight schedule. The company's primary scheduling concerns are aircraft fleet utilization and the waiting times of transfer passengers. Balancing the trade-off between these two criteria in a flight schedule is crucial for AnadoluJet's profitability. In this paper, we present the results of our study of AnadoluJet's flight-scheduling process. We provide a mathematical model that addresses this problem and then extend our studies and implement a heuristic algorithm for the development of a decision support system for the company. The objectives of the models we generated are to maximize fleet utilization, minimize waiting times for the majority of transfer passengers, and generate flight schedules subject to various constraints. The schedules that result from our models are superior to those that AnadoluJet's generated using its previous manual process. AnadoluJet currently uses our decision support system in its flight-scheduling process. © 2016 INFORMS
Turner syndrome and associated problems in turkish children: A multicenter study
Objective: Turner syndrome (TS) is a chromosomal disorder caused by complete or partial X chromosome monosomy that manifests various clinical features depending on the karyotype and on the genetic background of affected girls. This study aimed to systematically investigate the key clinical features of TS in relationship to karyotype in a large pediatric Turkish patient population. Methods: Our retrospective study included 842 karyotype-proven TS patients aged 0-18 years who were evaluated in 35 different centers in Turkey in the years 2013-2014. Results: The most common karyotype was 45,X (50.7%), followed by 45,X/46,XX (10.8%), 46,X,i(Xq) (10.1%) and 45,X/46,X,i(Xq) (9.5%). Mean age at diagnosis was 10.2±4.4 years. The most common presenting complaints were short stature and delayed puberty. Among patients diagnosed before age one year, the ratio of karyotype 45,X was significantly higher than that of other karyotype groups. Cardiac defects (bicuspid aortic valve, coarctation of the aorta and aortic stenosi) were the most common congenital anomalies, occurring in 25% of the TS cases. This was followed by urinary system anomalies (horseshoe kidney, double collector duct system and renal rotation) detected in 16.3%. Hashimoto’s thyroiditis was found in 11.1% of patients, gastrointestinal abnormalities in 8.9%, ear nose and throat problems in 22.6%, dermatologic problems in 21.8% and osteoporosis in 15.3%. Learning difficulties and/or psychosocial problems were encountered in 39.1%. Insulin resistance and impaired fasting glucose were detected in 3.4% and 2.2%, respectively. Dyslipidemia prevalence was 11.4%. Conclusion: This comprehensive study systematically evaluated the largest group of karyotype-proven TS girls to date. The karyotype distribution, congenital anomaly and comorbidity profile closely parallel that from other countries and support the need for close medical surveillance of these complex patients throughout their lifespan. © Journal of Clinical Research in Pediatric Endocrinology
Gas and seismicity within the Istanbul seismic gap
Understanding micro-seismicity is a critical question for earthquake hazard assessment. Since the devastating earthquakes of Izmit and Duzce in 1999, the seismicity along the submerged section of North Anatolian Fault within the Sea of Marmara (comprising the “Istanbul seismic gap”) has been extensively studied in order to infer its mechanical behaviour (creeping vs locked). So far, the seismicity has been interpreted only in terms of being tectonic-driven, although the Main Marmara Fault (MMF) is known to strike across multiple hydrocarbon gas sources. Here, we show that a large number of the aftershocks that followed the M 5.1 earthquake of July, 25th 2011 in the western Sea of Marmara, occurred within a zone of gas overpressuring in the 1.5–5 km depth range, from where pressurized gas is expected to migrate along the MMF, up to the surface sediment layers. Hence, gas-related processes should also be considered for a complete interpretation of the micro-seismicity (~M < 3) within the Istanbul offshore domain
An example of secondary fault activity along the North Anatolian Fault on the NE Marmara Sea Shelf, NW Turkey
Seismic data on the NE Marmara Sea Shelf indicate that a NNE-SSW-oriented buried basin and ridge system exist on the sub-marine extension of the Paleozoic Rocks delimited by the northern segment of the North Anatolian Fault (NS-NAF), while seismic and multi-beam bathymetric data imply that four NW-SE-oriented strike-slip faults also exist on the shelf area. Seismic data indicate that NW-SE-oriented strike-slip faults are the youngest structures that dissect the basin-ridge system. One of the NW-SE-oriented faults (F1) is aligned with a rupture of the North Anatolian Fault (NAF) cutting the northern slope of the Cinarcik Basin. This observation indicates that these faults have similar characteristics with the NS-NAF along the Marmara Sea. Therefore, they may have a secondary relation to the NAF since the principle deformation zone of the NAF follows the Marmara Trough in that region. The seismic energy recorded on these secondary faults is much less than that on the NAF in the Marmara Sea. These faults may, however, produce a large earthquake in the long term
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