scholarly journals Challenging Vertical Turbulence Mixing Schemes in a Tidally Energetic Environment: 1. 3‐D Shelf‐Sea Model Assessment

2019 ◽  
Vol 124 (8) ◽  
pp. 6360-6387 ◽  
Author(s):  
Maria V. Luneva ◽  
Sarah Wakelin ◽  
Jason T. Holt ◽  
Mark E. Inall ◽  
Igor E. Kozlov ◽  
...  
Keyword(s):  
Model Assessment ◽  
Turbulence Mixing ◽  
Shelf Sea ◽  
Vertical Turbulence ◽  
Mixing Schemes

scholarly journals Validation and intercomparison of two vertical-mixing schemes in the Mediterranean Sea

2006 ◽  
Vol 3 (6) ◽  
pp. 1945-1976 ◽  
Author(s):  
V. Fernández ◽  
L. Umlauf ◽  
S. Dobricic ◽  
H. Burchard ◽  
N. Pinardi
Keyword(s):  
Mediterranean Sea ◽  
Vertical Mixing ◽  
Weather Forecast ◽  
Shortwave Radiation ◽  
Medium Range Weather Forecast ◽  
Column Dynamics ◽  
Vertical Turbulence ◽  
Non Local ◽  
Mixing Schemes ◽  
The Mediterranean

Abstract. In this study, two types of vertical turbulence closure models are tested in the Mediterranean Sea in a one-dimensional configuration. The numerical experiments are performed at different locations in the Mediterranean for which the year 2004 is simulated. The model results are then compared and validated with in-situ temperature observations. For the model simulations, initial profiles of temperature and salinity come from the ARGO (Array for Real-time Geostrophic Oceanography) profiles. The surface forcing (momentum, heat) is calculated from bulk formulae using 6-hourly atmospheric data from the European Center for Medium Range Weather Forecast (ECMWF). The vertical mixing schemes tested in this study are a second-order statistical model (k-ε) and the non-local K-profile parameterization (KPP). Both schemes yield similar results in terms of reproducing the water column dynamics. A major source of discrepancy between model and observations comes from the uncertainties in the atmospheric forcing parameterization. At this point, net shortwave radiation data from NCEP atmospheric reanalysis has been used obtaining a more realistic Sea Surface Temperature (SST) compared with satellite observations for the summer months.

Dissolution of a CO2 lake, modeled by using an advanced vertical turbulence mixing scheme

2008 ◽  
Vol 2 (4) ◽  
pp. 511-519 ◽  
Author(s):  
Lars Inge Enstad ◽  
Kristin Rygg ◽  
Peter Mosby Haugan ◽  
Guttorm Alendal
Keyword(s):  
Turbulence Mixing ◽  
Vertical Turbulence

Therapeutic Effect of Metformin and Vitamin E Versus Prescriptive Diet in Obese Adolescents with Fatty Liver

2011 ◽  
Vol 81 (6) ◽  
pp. 398-406 ◽  
Author(s):  
Akcam ◽  
Boyaci ◽  
Pirgon ◽  
Kaya ◽  
Uysal ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Vitamin E ◽  
Fatty Liver ◽  
Liver Steatosis ◽  
Tnf Alpha ◽  
Dietary Advice ◽  
Model Assessment ◽  
Fasting Insulin ◽  
Alcoholic Fatty Liver ◽  
Obese Adolescents

Objective: The aim of the study was to determine whether metformin or vitamin E treatment for six months is effective in reducing body weight, blood pressure, and also ameliorating insulin resistance, adiponectin, and tumor necrosis factor (TNF)-alpha in obese adolescents with non-alcoholic fatty liver disease (NAFLD). Methods: Sixty-seven obese adolescents with liver steatosis (age range, 9 - 17 years) were included in the study. The metformin group received an 850-mg dose of metformin daily and the vitamin E group received 400 U vitamin E /daily, in capsule form for 6 months, plus an individually tailored diet, exercise, and behavioral therapy. Results: After 6 months later, there was a significant decline in body mass index, and fasting insulin and homeostatic model assessment (HOMA) values in all three groups. Moreover, in comparingson of changes in HOMA among the groups, the metformin- treated group showed significantly improved metabolic control and insulin sensitivity (HOMA) at the end of the study. There were no significant differences for changes of adiponectin, TNF-alpha, in all three groups after 6 months study. Conclusion: These data suggest that metformin treatment is more effective than dietary advice and vitamin E treatment in reducing insulin resistance, and also in ameliorating metabolic parameters such as fasting insulin and lipid levels, in obese adolescents having NAFLD.

Clinical factors correlated with vitamin D deficiency in patients with obesity scheduled for bariatric surgery: A single center experience

2020 ◽  
Vol 90 (3-4) ◽  
pp. 346-352
Author(s):  
Vincenzo Pilone ◽  
Salvatore Tramontano ◽  
Carmen Cutolo ◽  
Federica Marchese ◽  
Antonio Maria Pagano ◽  
...  
Keyword(s):  
Bariatric Surgery ◽  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Serum Vitamin ◽  
Inverse Correlation ◽  
Model Assessment ◽  
Cross Sectional ◽  
Serum Vitamin D ◽  
Female Sex ◽  
Vitamin D Levels

Abstract. We aim to assess the prevalence of vitamin D deficiency (VDD) in patients scheduled for bariatric surgery (BS), and to identify factors that might be associated with VDD. We conducted a cross-sectional observational study involving all consecutive patients scheduled for BS from 2017 to 2019. The exclusion criteria were missing data for vitamin D levels, intake of vitamin D supplements in the 3 months prior to serum vitamin D determination, and renal insufficiency. A total of 206 patients (mean age and body mass index [BMI] of 34.9 ± 10.7 years, and 44.3 ± 6.99 kg/m2, respectively) met the inclusion criteria and were enrolled for data analysis. VDD (<19.9 ng/mL), severe VDD (<10 ng/mL), and vitamin D insufficiency (20–29.9 ng/mL) were present in 68.8 %, 12.5 %, and 31.2 % of patients, respectively. A significant inverse correlation was found between vitamin D levels and initial BMI, parathyroid hormone, and homeostatic model assessment of insulin resistance (r = −0.280, p < 0.05; r = −0.407, p = 0.038; r = −0.445, p = 0.005), respectively. VDD was significantly more prevalent in patients with higher BMI [−0.413 ± 0.12, CI95 % (−0.659; −0.167), p = 0.006], whereas no significant association between hypertension [−1.005 ± 1.65, CI95 % (−4.338; 2.326), p = 0.001], and diabetes type 2 (T2D) [−0.44 ± 2.20, CI95 % (−4.876; 3.986), p = 0.841] was found. We observed significant association between female sex and levels of vitamin D [6.69 ± 2.31, CI95 % (2.06; 11.33), p = 0.006]. The present study shows that in patients scheduled for BS, VDD deficiency is common and was associated with higher BMI, and female sex.

The Weight Loss Effects of Branched Chain Amino Acids and Vitamin B6: A Randomized Controlled Trial on Obese and Overweight Women

2018 ◽  
Vol 88 (1-2) ◽  
pp. 80-89 ◽  
Author(s):  
Zahra Shakibay Novin ◽  
Saeed Ghavamzadeh ◽  
Alireza Mehdizadeh
Keyword(s):  
Amino Acids ◽  
Weight Loss ◽  
Body Composition ◽  
Vitamin B6 ◽  
Controlled Trial ◽  
Density Lipoprotein ◽  
Branched Chain Amino Acids ◽  
Model Assessment ◽  
Waist To Hip Ratio ◽  
Branched Chain

Abstract. Branched chain amino acids (BCAA), with vitamin B6 have been reported to improve fat metabolism and muscle synthesis. We hypothesized that supplementation with BCAA and vitamin B6 would result in more weight loss and improve body composition and blood markers related to cardiovascular diseases. Our aim was to determine whether the mentioned supplementation would affect weight loss, body composition, and cardiovascular risk factors during weight loss intervention. To this end, we performed a placebo-controlled randomized clinical trial in 42 overweight and obese women (BMI = 25–34.9 kg/m2). Taking a four-week moderate deficit calorie diet (–500 kcal/day), participants were randomized to receive BCAA (6 g/day) with vitamin B6 (40 mg/day) or placebo. Body composition variables measured with the use of bioelectrical impedance analysis, homeostatic model assessment, and plasma insulin, Low density lipoprotein, High density lipoprotein, Total Cholesterol, Triglyceride, and fasting blood sugar were measured. The result indicated that, weight loss was not significantly affected by BCAA and vitamin B6 supplementation (–2.43 ± 1.02 kg) or placebo (–1.64 ± 1.48 kg). However, significant time × treatment interactions in waist to hip ratio (P = 0.005), left leg lean (P = 0.004) and right leg lean (P = 0.023) were observed. Overall, supplementation with BCAA and vitamin B6 could preserve legs lean and also attenuated waist to hip ratio.

The interaction between dietary approaches to stop hypertension and MC4R gene variant in predicting cardiovascular risk factors

2020 ◽  
pp. 1-9
Author(s):  
Habib Yarizadeh ◽  
Alireza Bahiraee ◽  
Sara Asadi ◽  
Niloofar Sadat Maddahi ◽  
Leila Setayesh ◽  
...  
Keyword(s):  
Risk Factors ◽  
Cardiovascular Risk ◽  
Cardiovascular Risk Factors ◽  
Model Assessment ◽  
Iranian Women ◽  
Cvd Risk ◽  
Dash Diet ◽  
Melanocortin 4 Receptor Gene ◽  
Significant Difference ◽  
High Adherence

Abstract. Objective: The genetic variants near the melanocortin-4 receptor gene (MC4R), a key protein regulating energy balance and adiposity, have been related to obesity and cardiovascular risk factors. However, qualitative and quantitative aspects of diet may modulate the association of this polymorphism with obesity and cardiovascular diseases (CVDs). The aim of this study was to evaluate interactions among MC4R rs17782313, the Dietary Approaches to Stop Hypertension (DASH) diet and risk factors for CVDs. Method: This cross-sectional study was conducted on 266 Iranian women categorized by body mass index (BMI) range of 25–40 kg/m2 as overweight or obese. CVD risk factors included waist circumference (WC), lipid profile, blood pressure, insulin circulation and fasting blood sugar (FBS). Insulin and FBS were used to calculate homeostatic model assessment insulin resistance (HOMA-IR) Body composition was assessed by a multi-frequency bioelectrical impedance analyzer, InBody 770 scanner. Results: The findings of this study show that high adherence to the DASH diet in the CC groups were associated with decreased SBP and DBP compared to the TT group. In addition, a significant difference between women with high adherence to the DASH diet compared to low adherence was observed for body weight (p < 0.001), fat free mass (FFM) (p = 0.01) and BMI (p = 0.02). Women with the CC genotype had higher insulin (mg/dl) (mean and SD, for TT: 14.6 ± 4.6, TC: 17.3 ± 9.2, CC: 15.3 ± 4.8, p = 0.04) and HOMA-IR (mean for and SD, TT: 3.1 ± 1.07, TC: 3.9 ± 2.4, CC: 3.2 ± 1.1, p = 0.01) than TT group. Inclusion of potential confounding variables (age, physical activity, BMI and daily caloric intake) did not attenuate the difference. Conclusion: Among overweight/obese Iranian women with the CC genotype, incorporating the DASH diet may serve as a dietary prescription to decrease CVD risk. A dietary intervention trial is warranted.

Early Renal Dysfunction in Obese Patients with Insulin Resistance

2019 ◽  
Vol 26 (3) ◽  
pp. 261-265
Author(s):  
Natalia Pertseva ◽  
Mariia Rokutova
Keyword(s):  
Insulin Resistance ◽  
Renal Function ◽  
Renal Dysfunction ◽  
Filtration Rate ◽  
Diagnostic Value ◽  
Glomerular Hyperfiltration ◽  
Model Assessment ◽  
Homa Index ◽  
Obese Patients ◽  
Homeostasis Model Assessment

Abstract Background and aims. Obese individuals have insulin resistance status assessed in the present study by the HOMA index (“Homeostasis model assessment”). This prospective study assessed renal disorders in the insulin resistance in obese patients. Material and Methods. The study included 73 young obese patients. The assessment included the HOMA index before meal and parameters of renal function (glomerular filtration rate, albuminuria, β2-microglobulinuria). Results. In young obese, insulin-resistance patients, glomerular hyperfiltration and β2-microglobulinuria are found in 77.0 and 93.4% of cases respectively. The albuminuria is noted in some cases, which reduces diagnostic value. Conclusions. In young obese patients with insulin resistance, glomerular hyperfiltration and β2-microglobulinuria are main diagnostic markers of renal dysfunction.

Risk assessment models with functionally different influences on natural and technical systems

2020 ◽  
Vol 89 ◽  
pp. 8-19
Author(s):  
V. A. Minaev ◽  
◽  
N. G. Topolsky ◽  
A. O. Faddeev ◽  
R. O. Stepanov ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Differential Equations ◽  
Research Area ◽  
Practical Implementation ◽  
Model Assessment ◽  
Mathematical Functions ◽  
Effective Response ◽  
Risk Assessment Models ◽  
Technical Systems ◽  
Material Values

Introduction. The complex combination of natural and technogenic factors that lead to dangerous threats to the health and life of the population, as well as to material values, creates a need to develop special mathematical models for risk assessment in the relevant territories. Herewith it is important to take into account the significant differences between these factors. The new areas of research are models that describe natural and technogenic risks using differential equations that reflect different types of functions. The article presents the development of this research area. Goals and objectives. The goal of the article is to create a model for risk assessment in natural and technical systems (PTS), based on taking into account the influences of different natural and technogenic factors on them. Objectives include justification, construction and practical implementation of the mathematical model of risk assessment in the form of differential equations system. Methods include interpretation of the considered influences on PTS in terms of risks and assessment of the dynamic interaction of natural and technogenic factors in the form of inhomogeneous differential equations. Results and discussion. Solutions for models of assessing complex natural and technogenic risks in relation to two cases that differ in NTS are found: functionally different external natural and technogenic influences on PTS, which are understood as their type, in which the effects of both natural and technogenic factors are described by different mathematical functions. Conclusions. The first model considers parabolic (reflecting threats whose intensity gradually decreases with distance from the epicenter) and linear types of influences (reflecting sudden threats). The second model considers parabolic and hyperbolic (reflecting threats, the intensity of which decreases sharply over time) types of influences. It is concluded that it is necessary to create a special computer album of complex influences on the PTS in order to prevent "replay" of various situations and develop the most effective response to emerging dangers from the EMERCOM units and other structures. Key words: model, assessment, natural and technogenic risks, functionally different influences, counteraction, EMERCOM units.

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