bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics of the mean Asian summer monsoon in a maximally simplified model
Authors: Mak Mankin 
Published: April 2008

AbstractA two‐layer quasi‐geostrophic model, containing the bare essential orographic and thermal forcings, is used as a maximally simplified model for delineating the nature of the mean Asian summer monsoon circulation (ASM). The solution reveals that the prototype ASM circulation consists of two main components. The western part of it is a greatly elongated and skewed baroclinic vortical circulation. The lower and upper features of the baroclinic vortex are the model counterparts of the Monsoon Low and the Tibetan High respectively. The eastern part of the model ASM is a composite baroclinic Rossby wave‐packet which manifests itself at the lower and upper levels as the model counterparts of the surface Subtropical High and upper‐level Monsoon Trough. The centre of the skewed vortex and the root of the wave‐packet are collocated over East Asia arising from a common source of excitation. This overall circulation is interpreted in terms of potential vorticity dynamics. Furthermore, the ascending motion field is consistent with the notion that the thermal forcing is largely self‐reinforcing. The descending motion over the model Middle East supports the notion that the desert climate is an integral part of the ASM. The roles of the individual model forcing elements are also delineated and the caveats of the analysis elaborated. Copyright © 2008 Royal Meteorological Society
Circumglobal teleconnections and wave packets associated with Israeli winter precipitation
Authors: Feldstein Steven B. , Dayan Uri 
Published: April 2008

AbstractThis investigation performs diagnostic analyses with NCEP/NCAR reanalysis data and Israeli precipitation data to examine the dynamical processes that drive the teleconnection pattern associated with Israeli winter precipitation anomalies.A dipole teleconnection pattern with one centre of action over western Europe and another centre of action over the eastern Mediterranean (EM) is found to be associated with the winter precipitation anomalies in Israel. This pattern is referred to as the southern Levant (SL) pattern. The positive (negative) phase of the SL pattern is found to be closely associated with enhanced (reduced) precipitation in Israel. Composites of the 300 hPa stream‐function field show that both phases of the SL pattern are associated with eastward propagating wave packets that traverse about three‐quarters of the distance across the globe. These wave packets, which have a phase speed that is close to zero, originate over the northeast Pacific (the east coast of North America) for the positive (negative) SL phase, and propagate eastward across the North Atlantic, western Europe, the EM, and southern Asia, until they eventually decay over the northwest Pacific. As these wave packets pass over western Europe and the EM, the SL pattern is triggered and anomalies in Israeli winter precipitation occur.The SL pattern is found to have an e‐folding time‐scale of 4 days, which is determined by the group velocity of the wave packet. The time‐averaged spatial structure of the circumglobal wave packet closely resembles the first empirical orthogonal function of the hemispheric 300 hPa meridional wind field. This suggests that the circumglobal wave packet may be a fundamental pattern of variability which is relevant for the entire Northern Hemisphere. Copyright © 2008 Royal Meteorological Society
Noise due to the Monte Carlo independent‐column approximation: short‐term and long‐term impacts in ECHAM5
Authors: Räisänen P. , Järvenoja S. , Järvinen H. 
Published: April 2008

AbstractThe Monte Carlo independent‐column approximation (McICA), as a method for computing domain‐average radiative fluxes, allows a flexible treatment of unresolved cloud structure, and is unbiased with respect to the full independent‐column approximation, but its flux estimates contain conditional random noise. In our previous study with the ECHAM5 atmospheric general‐circulation model with prescribed sea‐surface temperatures (SSTs), McICA noise caused a slight reduction in low‐cloud fraction. Here, we first demonstrate that this feature originates from an immediate, nonlinear response of precipitation formation to McICA's random errors in radiative‐heating rates, and is subsequently amplified by a radiative feedback. We then study the long‐term impacts of McICA noise on climate in ECHAM5 simulations employing a mixed‐layer ocean model. The use of interactive rather than prescribed SST somewhat amplifies the reduction in low‐cloud fraction, which contributes to an overall warming of simulated climate with increasing McICA noise. For a typical implementation of McICA, the global‐mean 2 m air temperature is 0.33 K higher than for a low‐noise reference simulation. A 0.1 µm systematic increase in cloud‐droplet effective radius re causes a similar global‐mean warming (0.31 K), with generally similar spatial patterns. However, in the eastern tropical Pacific, McICA noise has locally larger effects than the uniform perturbation in re. It is concluded that the climatic impacts of McICA noise mainly represent a straightforward response to the systematic perturbation in the surface and top‐of‐atmosphere energy budget related to the initial reduction in low cloudiness. Copyright © 2008 Royal Meteorological Society
Effect of surface modification of montmorillonite on the properties of aromatic polyamide/clay nanocomposites
Authors: Zulfiqar Sonia , Ishaq Muhammad , Sarwar Muhammad Ilyas 
Published: April 2008

AbstractThe surface modification of montmorillonite clay was carried out through ion‐ exchange reaction using p‐phenylenediamine as a modifier. This modified clay was employed to prepare aromatic polyamide/organoclay nanocomposite materials. The dispersion behavior of clay was examined in the polyamide matrix. Polyamide chains were synthesized from 4‐aminophenyl sulfone and isophthaloyl chloride (IPC) in dimethylacetamide. These amide chains were suitably end‐capped with carbonyl chloride end groups to interact chemically with modified montmorillonite clay. The resulting nanocomposite films containing 2–20 wt% of organoclay were characterized by TEM, X‐ray diffraction (XRD), thin‐film tensile testing; thermogravimetric analysis (TGA), differential scanning calorimetric (DSC) and water absorption measurements. Mechanical testing revealed that modulus and strength improved up to 6 wt% organoclay loading while elongation and toughness of nanocomposites decreased with the addition of clay content in the matrix. Thermal decomposition temperatures of the nanocomposites were in the range 225–450 °C. These nanocomposites expressed increase in the glass‐transition temperature values relative to pure polyamide describing interfacial interactions among the phases. The percent water uptake of these composites reduced upon the addition of modified layered silicate depicting improved barrier properties. Copyright © 2008 John Wiley & Sons, Ltd.
Serum prolactin as a tool for the follow‐up of treated DHPR‐deficient patients
Authors: Concolino D. , Muzzi G. , Rapsomaniki M. , Moricca M. T. , Pascale M. G. , Strisciuglio P. 
Published: April 2008

SummaryDeficiency of dihydropteridine reductase causes a variant form of phenylketonuria associated with a devastating neurological disease characterized by mental retardation, hypokinesis and other features relating to basal ganglia disorder. Hyperphenylalaninaemias with tetrahydrobiopterin deficiency make up about 1–3% of all hyperphenylalaninaemias. We describe three patients from Calabria, a southern region of Italy, who have a dihydropteridine reductase deficiency, caused by the same mutation (p.L14P) also found in the nearby region of Sicily. We report the evolution of clinical and biochemical data during the treatment of these patients where we used prolactin serum determination to adapt the specific therapy. This report suggests that serum prolactin levels can be a good biomarker for optimal dosage of hydroxylated precursors in long‐term treatment monitoring.
Identity‐in‐context is not yet identity development‐in‐context
Authors: Bosma Harke A. , Kunnen E. Saskia 
Published: April 2008

ABSTRACTIn this discussion, we summarize the main aspects of the research presented in the papers and discuss what we see as their strong points. To analyze recent developments in identity research, we compared the present issue with the special issue of the Journal of Adolescence in 1996 on ‘Identity Development in Context’. In that issue it was concluded that further research is necessary to “detail the ways in which contextual variables may interact both with one another as well as with individual personality variables to determine the course of the identity formation process”.In the papers in this issue, the influence of the context has received much more attention than 20 years ago. However, they still have serious limitations with regard to the study of the developmental process. Not more than one study uses a longitudinal design. To stimulate research into developmental processes we conclude with a plea for longitudinal studies over long periods, with enough measurement points to distinguish between different patterns, and for more conceptual attention for what identity development is about.
Equilibria in the system Au–Ag–S–fluid: computed and experimental data
Authors: Laptev Yu.V. 
Published: April 2008

Abstract
We present results of computations on the interaction of solid-phase electrum–argentite–pyrite (weight ratios 2⋅10−5/2⋅10−3/1 and 2⋅10−5/4⋅10−2/1) association with Cl-containing aqueous moderately acid solutions (0.5m NaCl, pH = 3.08) at 300 °C and 500 bars. These data are a physicochemical basis for predicting the geochemical behavior of Au and Ag during the hydrothermal-metasomatic transformation of Au-Ag-pyrite. We also propose a technique of study of this process based on the phase equilibria of the subsystem Au–Ag–S with the aqueous solution at different liquid/solid (l/s) ratios, with the use of new graphic diagrams. The relationship of the composition of the solid-phase association with l/s ratio in real boundary conditions (Au = 17 ppm, mAu/mAg = 10–3.57–10–2.28) is shown. The maximum l/s values for complete leaching of gold and silver (l/smax = 200–800) are estimated. It has been established that argentite is the first to dissolve when mAu/mAg(s) &gt; mAu/mAg(sol), and electrum, when mAu/mAg(s) &lt; mAu/mAg(sol).
The experimental results showed that at 300 °C, the conversion of electrum (NAu = 300‰) nonequilibrated with pyrite into an Au-richer form (NAu = 730‰) and argentite follows an intricate kinetic scheme. Using the Pilling-Bedwords kinetic equation for processing data yielded the process rate constant K = 2.8(±0.5)⋅10−5 g2⋅cm−4⋅day−1. With this equation, the time of the complete conversion of 200 μm thick flat gold grains is 604 days. These data evidence a significant role of kinetic factors in hydrothermal-metasomatic processes involving native gold, which requires combination of thermodynamic and kinetic approaches on the construction of geologo-genetic models for hydrothermal sulfide formation.
Simulating the heating of z-pinch plasmas with short laser pulses
Authors: WIENEKE S. , BRÜCKNER S. , VIÖL W. 
Published: April 2008

AbstractThe longitudinal heating of a z-pinch plasma with short laser pulses is simulated using COMSOL Multiphysics. The heating of an existing pinch plasma for different electron densities with a short laser pulse is shown. It is illustrated that the initial electron density of the plasma has a significant impact on penetration of the pulse and subsequent heating of the plasma. With a Nd:YAG laser pulse the most effective heating occurs when the initial electron density is about 1/15 of the critical electron density of the plasma. It is shown that by increasing the initial electron density by even a factor of two above this level causes the absorption to increase dramatically, preventing penetration of the laser pulse and greatly limiting the heating of the plasma.
High Expression of Complement Components in Omental Adipose Tissue in Obese Men
Authors: Gabrielsson Britt G. , Johansson Jenny M. , Lönn Malin , Jernås Margareta , Olbers Torsten , Peltonen Markku , Larsson Ingrid , Lönn Lars , Sjöström Lars , Carlsson Björn , Carlsson Lena M.S. 
Published: April 2008

AbstractObjective: Accumulation of visceral fat is recognized as a predictor of obesity‐related metabolic disturbances. Factors that are predominantly expressed in this depot could mediate the link between visceral obesity and associated diseases.Research Methods and Procedures: Paired subcutaneous and omental adipose tissue biopsies were obtained from 10 obese men. Gene expression was analyzed by DNA microarrays in triplicate and by real‐time polymerase chain reaction. Serum C3 and C4 were analyzed by radial immunodiffusion assays in 91 subjects representing a cross section of the general population. Body composition was measured by computerized tomography.Results: Complement components C2, C3, C4, C7, and Factor B had higher expression in omental compared with subcutaneous adipose tissue (∼2‐, 4‐, 17‐, 10‐, and 7‐fold, respectively). In addition, adipsin, which belongs to the alternative pathway, and the classical pathway components C1QB, C1R, and C1S were expressed in both depots. Analysis of tissue distribution showed high expression of C2, C3, and C4 in omental adipose tissue, and only liver had higher expression of these genes. Serum C3 levels correlated with both visceral and subcutaneous adipose tissue in both men (r = 0.65 and p < 0.001 and r = 0.52 and p < 0.001, respectively) and women (r = 0.34 and p = 0.023 and r = 0.49 and p < 0.001, respectively), whereas C4 levels correlated with only visceral fat in men (r = 0.36, p = 0.015) and with both depots in women (visceral: r = 0.58, p < 0.001; and subcutaneous: r = 0.51, p < 0.001).Discussion: Recent studies show that the metabolic syndrome is associated with chronically elevated levels of several immune markers, some of which may have metabolic effects. The high expression of complement genes in intra‐abdominal adipose tissue might suggest that the complement system is involved in the development of visceral adiposity and/or contributes to the metabolic complications associated with increased visceral fat mass.
Medium‐Chain Oil Reduces Fat Mass and Down‐regulates Expression of Adipogenic Genes in Rats
Authors: Han Jianrong , Hamilton James A. , Kirkland James L. , Corkey Barbara E. , Guo Wen 
Published: April 2008

AbstractObjective: To test the hypothesis that adipose tissue could be one of the primary targets through which medium‐chain fatty acids (MCFAs) exert their metabolic influence.Research Methods and Procedures: Sprague‐Dawley rats were fed a control high‐fat diet compared with an isocaloric diet rich in medium‐chain triglycerides (MCTs). We determined the effects of MCTs on body fat mass, plasma leptin and lipid levels, acyl chain composition of adipose triglycerides and phospholipids, adipose tissue lipoprotein lipase activity, and the expression of key adipogenic genes. Tissue triglyceride content was measured in heart and gastrocnemius muscle, and whole body insulin sensitivity and glucose tolerance were also measured. The effects of MCFAs on lipoprotein lipase activity and adipogenic gene expression were also assessed in vitro using cultured adipose tissue explants or 3T3‐L1 adipocytes.Results: MCT‐fed animals had smaller fat pads, and they contained a considerable amount of MCFAs in both triglycerides and phospholipids. A number of key adipogenic genes were down‐regulated, including peroxisome proliferator activated receptor γ and CCAAT/enhancer binding protein α and their downstream metabolic target genes. We also found reduced adipose tissue lipoprotein lipase activity and improved insulin sensitivity and glucose tolerance in MCT‐fed animals. Analogous effects of MCFAs on adipogenic genes were found in cultured rat adipose tissue explants and 3T3‐L1 adipocytes.Discussion: These results suggest that direct inhibitory effects of MCFAs on adiposity may play an important role in the regulation of body fat development.
Obesity in 70‐Year‐Old Subjects as a Risk Factor for 15‐Year Coronary Heart Disease Incidence
Authors: Dey Debashish K. , Lissner Lauren 
Published: April 2008

AbstractObjective: To investigate the role of obesity in general and waist circumference (WC) and BMI in particular as risk factors for 15‐year incidence of coronary heart disease (CHD) in the elderly.Research Methods and Procedures: This prospective study was based on 1597 (737 males and 860 females) 70‐year‐olds free from CHD and participants of three birth cohorts examined in 1971 to 1972 (Cohort I), 1976 to 1977 (Cohort II), and 1981 to 1982 (Cohort III) at Göteborg, Sweden. Fifteen‐year incidence of CHD (fatal and nonfatal) was ascertained from follow‐up examinations and registers. Relative risk (RR) for first ever CHD in reference to the lowest quartiles of WC and BMI was calculated from Cox regression.Results: In males, RRs for CHD in the highest WC and BMI quartiles were 1.36 [95% confidence interval (CI) 1.00 to 1.85] and 1.42 (95% CI 1.04 to 1.92), respectively, after adjustment for cohorts, smoking habits, diabetes, systolic blood pressure, and total cholesterol. In men, the risk associated with WC was independent of BMI. Neither WC nor BMI was related to CHD risk in females. After exclusion of first 5‐year all‐cause deaths, the adjusted RRs in the highest WC and BMI quartiles in males were 1.47 (95% CI 1.06 to 2.04) and 1.42 (1.04 to 1.92), respectively. In females, a significantly higher RR of 1.41 (95% CI 1.02 to 1.94) was observed in the second BMI quartile only after such exclusions.Discussion: WC, an indicator of both central and general obesity, appears to be a stronger predictor of CHD than BMI in elderly males, but in females, obesity was not a risk factor for CHD.
Meal Pattern Analysis of Diet‐Induced Obesity in Susceptible and Resistant Rats
Authors: Farley Constance , Cook John A. , Spar Brian D. , Austin Theodore M. , Kowalski Timothy J. 
Published: April 2008

AbstractObjective: To characterize the meal patterns of free feeding Sprague‐Dawley rats that become obese or resist obesity when chronically fed a high‐fat diet.Research Methods and Procedures: Male Sprague‐Dawley rats (N = 120) were weaned onto a high‐fat diet, and body weight was monitored for 19 weeks. Rats from the upper [diet‐induced obese (DIO)] and lower [diet‐resistant (DR)] deciles for body‐weight gain were selected for study. A cohort of chow‐fed (CF) rats weight‐matched to the DR group was also studied. Food intake was continuously monitored for 7 consecutive days using a BioDAQ food intake monitoring system.Results: DIO rats were obese, hyperphagic, hyperleptinemic, hyperinsulinemic, hyperglycemic, and hypertriglyceridemic relative to the DR and CF rats. The hyperphagia of DIOs was caused by an increase in meal size, not number. CF rats ate more calories than DR rats; however, this was because of an increase in meal number, not size. When expressed as a function of lean mass, CF and DR rats consumed the same amount of calories. The intermeal intervals of DIO and DR rats were similar; both were longer than CF rats. The nocturnal satiety ratio of DIO rats was significantly lower than DR and CF rats. The proportion of calories eaten during the nocturnal period did not differ among groups.Discussion: The hyperphagia of a Sprague‐Dawley rat model of chronic diet‐induced obesity is caused by an increase in meal size, not number. These results are an important step toward understanding the mechanisms underlying differences in feeding behavior of DIO and DR rats.
Weekend Eating in the United States Is Linked with Greater Energy, Fat, and Alcohol Intake
Authors: Haines Pamela S. , Hama Mary Y. , Guilkey David K. , Popkin Barry M. 
Published: April 2008

AbstractObjectives: To determine if macronutrient consumption for the U.S. population is greater on weekend days than weekdays.Research Methods and Procedures: The nationally representative 1994 to 1996 Continuing Survey of Food Intakes by Individuals was used for this analysis. Dietary intake was assessed using two independent days of dietary recall data. Ordinary least squares multivariate analysis was used to analyze dietary outcome variables to explore the effect of weekend day vs. weekday intake.Results: This study's results indicate that statistically significant dietary intake differences occur for different days of the week but not for all age groups—nor for all nutrients. The average American, 2 years and older, consumes 82 kcal more per day on each weekend day (Friday through Sunday) than they do on weekdays (Monday through Thursday). These overall increases in dietary intake are significant for the overall sample and are largest for the 19‐ to 50‐year‐old age group; among this age group, the weekend day increase (vs. weekday) is 115 kcal/d. The increased proportions of energy from fat and alcohol consumed on weekends are greater for this adult age group by 0.7% and 1.4%, respectively, whereas the proportion of energy from carbohydrate decreases 1.6%.Discussion: The effects of weekend days on nutrient intake are substantial and should be considered in future clinical and population‐based interventions and in dietary monitoring and research in the U.S.
Patterns of Overweight, Inactivity, and Snacking in Chinese Children
Authors: Waller Carrie E. , Du Shufa , Popkin Barry M. 
Published: April 2008

AbstractObjective: To examine patterns of inactivity and snacking and their relationship with overweight status in Chinese children.Research Methods and Procedures: The study population was drawn from the 1997 China Health National Survey (1385 children, ages 6 to 11 years), conducted with a representative sample from nine provinces. The 2000 Centers for Disease Control and Prevention BMI charts were used to calculate “at risk of overweight” as those above the 85th percentile. Three days of 24‐hour recall dietary data and detailed questions on physical activity and inactivity for the previous 7 days were used.Results: 9.4% of the children were classified as overweight. Weekly mean and range of hours spent watching television/videos, playing video games, studying, and in inactive transport were 5.1 (0 to 35), 0.3 (0 to 10), 4.7 (0 to 60), and 0.14 (0 to 4.2), respectively. Television/video viewing and studying did not differ in any meaningful manner between overweight and normal weight children. Snacking is inconsequential in China, comprising only 0.9% of energy intake.Discussion: Chinese children are less overweight, less inactive, and less likely to ingest calories as snacks than children in the U.S. The absence of impact of these measures of inactivity, which are below an hour per day for the average Chinese child, indicate the possible value of limiting television viewing and other types of inactivity in other countries. Modern Western‐style television programming and advertising started to come to China after 1997; therefore, extensive changes in television viewing patterns are expected to emerge.