bluuebunny/crossref_metadata_2025 huggingface dataset:
On‐line state estimation for nonlinear dynamical systems
Authors: Dmitruk Natalia M.
Published: August 2008

A problem of estimation of states of a dynamical object on the base of incomplete and inexact measurements is studied. The focus is on a set‐based estimation of states required for construction of optimal guaranteeing feedbacks. In particular, the aim is to construct at every current time instant polyhedral approximations of sets of all states consistent with the obtained measurements. A problem of constructing estimates, associated with these approximations, is called an optimal observation problem. This note presents a numerical method for solving optimal observation problems for nonlinear dynamical systems. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bifurcations on a spring‐pendulum oscillator
Authors: Gonzalez‐Buelga A. , Kyrychko Y. , Wagg D.J.
Published: August 2008

In this paper we study experimentally the dynamics of a non linear system: a spring pendulum coupled to an oscillator. The system was tested using a hybrid technique called Real Time Dynamic Substructuring (RTDS)[1, 2]. RTDS is a testing technique that involves splitting the system under study into two subsystems: one will be physically tested (physical substructure) and the other will be simulated in the computer (numerical model). These substructures interact in real time through a set of transfer systems. RTDS is a very powerful experimental methodology that not only allows full scale and real time testing but also real‐time bifurcation tracking in complex engineering systems [3, 4]. In our hybrid experiment the spring pendulum is taken to be the physical substructure while oscillator is the simulated numerical model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐order accurate iterative solution of the Navier–Stokes equations for incompressible flows
Authors: Henniger Rolf , Obrist Dominik , Kleiser Leonhard
Published: August 2008

An iterative solution scheme for the incompressible Navier–Stokes equations is presented. It is split into inner and outer iteration cycles, such that the momentum and continuity equations are satisfied within prescribed accuracy. The spatial discretization is based on high‐order finite differences which makes it well suited for massively parallel computers. This is demonstrated in a scaling test. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical analysis of uncertainties in the effective material behaviour of disordered structural foams
Authors: Hohe Jörg , Hardenacke Volker
Published: August 2008

The present contribution is concerned with a numerical analysis of the uncertainties in the structural response of threedimensional structural foams with partially open cells. The effective thermo mechanical material response is determined by means of an energy based homogenization procedure. Stochastic effects in the geometry and topology of the microstructure are treated by means of a repeated analysis of small‐scale representative volume elements with prescribed relative density and prescribed cell size distribution. The results are evaluated by stochastic methods. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of contact line dynamics for two‐phase flow
Authors: Kreiss Gunilla
Published: August 2008

We introduce a new model for capillary dominated two‐phase flow. Numerical computations demonstrate that it is capable of qualitatively capturing the dynamics of contact lines. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Finite‐element method simulation of rotating disk flow: effect of the transport of a chemical species
Authors: Pontes José , Rabello dos Anjos Gustavo , Mangiavacchi Norberto
Published: August 2008

Electrochemical cells containing an iron rotating disk electrode which is dissolved in the electrolyte, an 1 M H2SO4 solution present a current instability in the plateau region, where the current is controlled by the mass transport. Dissolution of the electrode gives rise to a thin concentration boundary layer, due to a Schmidt number Sc = 2000. This boundary layer, together with the potential applied to the electrode, leads to an increase in the fluid viscosity and in a decrease in the diffusion coefficient, coupling the concentration and the chemical species field. Since the current is proportional to the concentration gradient at the interface, an instability of the coupled fields at Reynolds numbers attained in experimental conditions could be responsible for the current instability. Mangiavacchi [1] performed a linear stability analysis of the problem and showed that this is indeed the case. In this paper we review the main results of the stability analysis and present the main features of the FEM code recently developed in our group, to proceed with the investigation of the current instability observed in electrochemical cells. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Residual distribution schemes for Bondi‐Hoyle accretion
Authors: Rossmanith James A.
Published: August 2008

Black hole accretion is a key component in astrophysical phenomena such as gamma‐ray bursts and quasars. As a step towards understanding such phenomena, accurate and efficient computational methods for simulating gas dynamics in the presence of black holes must be developed. In this work a residual distribution scheme on unstructured grids is constructed for solving the general relativistic version of the compressible Euler equations. In particular, we simulate Bondi‐Hoyle accretion onto a Schwarzschild black hole. Presented here are preliminary results in a larger effort to develop high‐order methods on unstructured meshes for general relativistic flows. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bayesian flux balance analysis applied to a skeletal muscle metabolic model
Authors: Calvetti Daniela , Heino Jenni , Somersalo Erkki , Tunyan Knarik
Published: August 2008

The steady state condition of two‐compartment skeletal muscle model is considered. The inverse problem is to estimate the reaction and transport fluxes, as well as the concentrations in venous blood when the stoichiometry and bound constraints for the fluxes and the concentrations are given. A new methodology based on a Bayesian statistical approach to the flux balance analysis (FBA) is proposed. We show how the bound constraints and optimality condition can be incorporated into the model in the Bayesian framework by proper construction of the prior densities. An effective Markov Chain Monte Carlo (MCMC) scheme to explore the posterior densities is proposed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
SIMS and MALDI MS imaging of the spinal cord
Authors: Monroe Eric B. , Annangudi Suresh P. , Hatcher Nathan G. , Gutstein Howard B. , Rubakhin Stanislav S. , Sweedler Jonathan V.
Published: August 2008

The application of MS to imaging, or MS imaging (MSI), allows for the direct investigation of tissue sections to identify biological compounds and determine their spatial distribution. We present an approach to MSI that combines secondary ion MS (SIMS) and MALDI MS for the imaging and analysis of rat spinal cord sections, thereby enhancing the chemical coverage obtained from an MSI experiment. The spinal cord is organized into discrete, anatomically defined areas that include motor and sensory networks composed of chemically diverse cells. The MSI data presented here reveal the spatial distribution of multiple phospholipids, proteins, and neuropeptides obtained within single, 20 μm sections of rat spinal cord. Analyte identities are initially determined by primary mass match and confirmed in follow‐up experiments using LC MS/MS from extracts of adjacent spinal cord sections. Additionally, a regional analysis of differentially localized signals serves to rapidly screen compounds of varying intensities across multiple spinal regions. These MSI analyses reveal new insights into the chemical architecture of the spinal cord and set the stage for future imaging studies of the chemical changes induced by pain, anesthesia, and drug tolerance.
Protein and peptides in pictures: Imaging with MALDI mass spectrometry
Authors: Goodwin Richard J. A. , Pennington Stephen R. , Pitt Andrew R.
Published: August 2008

Imaging using MS has the potential to deliver highly parallel, multiplexed data on the specific localization of molecular ions in tissue samples directly, and to measure and map the variations of these ions during development and disease progression or treatment. There is an intrinsic potential to be able to identify the biomarkers in the same experiment, or by relatively simple extension of the technique. Unlike many other imaging techniques, no a priori knowledge of the markers being sought is necessary. This review concentrates on the use of MALDI‐MS for MS imaging (MSI) of proteins and peptides, with an emphasis on mammalian tissue. We discuss the methodologies used, their potential limitations, overall experimental considerations and progress that has been made towards establishing MALDI‐MSI as a routine technique for the spatially resolved measurement of peptides and proteins. As well as determining the local abundance of individual molecular ions, there is the potential to determine their identity within the same experiment using relatively simple extensions of the basic techniques. In this way MSI offers an important opportunity for biomarker discovery and identification.
Iterative cluster‐NMA: A tool for generating conformational transitions in proteins
Authors: Schuyler Adam D. , Jernigan Robert L. , Qasba Pradman K. , Ramakrishnan Boopathy , Chirikjian Gregory S.
Published: August 2008

Computational models provide insight into the structure–function relationship in proteins. These approaches, especially those based on normal mode analysis, can identify the accessible motion space around a given equilibrium structure. The large magnitude, collective motions identified by these methods are often well aligned with the general direction of the expected conformational transitions. However, these motions cannot realistically be extrapolated beyond the local neighborhood of the starting conformation. In this article, the iterative cluster‐NMA (icNMA) method is presented for traversing the energy landscape from a starting conformation to a desired goal conformation. This is accomplished by allowing the evolving geometry of the intermediate structures to define the local accessible motion space, and thus produce an appropriate displacement. Following the derivation of the icNMA method, a set of sample simulations are performed to probe the robustness of the model. A detailed analysis of β1,4‐galactosyltransferase‐T1 is also given, to highlight many of the capabilities of icNMA. Remarkably, during the transition, a helix is seen to be extended by an additional turn, emphasizing a new unknown role for secondary structures to absorb slack during transitions. The transition pathway for adenylate kinase, which has been frequently studied in the literature, is also discussed. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Evaluating spatial methods for investigating global clustering and cluster detection of cancer cases
Authors: Huang Lan , Pickle Linda W. , Das Barnali
Published: August 2008

There have been articles on comparing methods for global clustering evaluation and cluster detection in disease surveillance, but power and sample size (SS) requirements have not been explored for spatially correlated data in this area. We are developing such requirements for tests of spatial clustering and cluster detection for regional cancer cases. We compared global clustering methods including Moran'sI, Tango's and Besag–Newell'sRstatistics, and cluster detection methods including circular and elliptic spatial scan statistics (SaTScan), flexibly shaped spatial scan statistics, Turnbull's cluster evaluation permutation procedure, local indicators of spatial association, and upper‐level set scan statistics. We identified eight geographic patterns that are representative of patterns of mortality due to various types of cancer in the U.S. from 1998 to 2002. We then evaluated the selected spatial methods based on state‐ and county‐level data simulated from these different spatial patterns in terms of geographic locations and relative risks, and varying SSs using the 2000 population in each county. The comparison provides insight into the performance of the spatial methods when applied to varying cancer count data in terms of power and precision of cluster detection. Copyright © 2008 John Wiley & Sons, Ltd.
Analyses of cumulative incidence functions via non‐parametric multiple imputation
Authors: Ruan Ping K. , Gray Robert J.
Published: August 2008

We describe a non‐parametric multiple imputation method that recovers the missing potential censoring information from competing risks failure times for the analysis of cumulative incidence functions. The method can be applied in the settings of stratified analyses, time‐varying covariates, weighted analysis of case‐cohort samples and clustered survival data analysis, where no current available methods can be readily implemented. The method uses a Kaplan–Meier imputation method for the censoring times to form an imputed data set, so cumulative incidence can be analyzed using techniques and software developed for ordinary right censored survival data. We discuss the methodology and show from both simulations and real data examples that the method yields valid estimates and performs well. The method can be easily implemented via available software with a minor programming requirement (for the imputation step). It provides a practical, alternative analysis tool for otherwise complicated analyses of cumulative incidence of competing risks data. Copyright © 2008 John Wiley & Sons, Ltd.
Long‐term survivor model with bivariate random effects: Applications to bone marrow transplant and carcinoma study data
Authors: Lai Xin , Yau Kelvin K. W.
Published: August 2008

Cured patients (or the so‐called long‐term survivors) are increasingly being observed in clinical trial studies. As exemplified in two data sets, the bone marrow transplantation study for leukaemia patients and the multi‐centre study for patients with carcinoma in the oropharynx, a considerable portion of the patients in these studies are deemed to be cured. With the presence of random hospital/centre effects, a long‐term survivor model with bivariate random effects is proposed to analyse clustered survival data with a possible portion of cured patients. This model extends earlier work by allowing random effects in both the cured fraction and the hazard function parts to follow a bivariate normal distribution, which gives a generalized model with an additional correlation parameter governing the relationship between the recovery probability and the instantaneous failure rate due to the hospital/centre effects. By adopting the GLMM formulation, random effects are incorporated in the model via the linear predictor terms. REML estimation of parameters is achieved via the EM algorithm. Application to the two sets of data illustrates the usefulness of the proposed model. A simulation study is conducted to assess the performance of the estimators, under the proposed numerical estimation scheme. Copyright © 2008 John Wiley & Sons, Ltd.
Improving the efficiency of inductive logic programming systems
Authors: Fonseca Nuno A. , Costa Vítor Santos , Rocha Ricardo , Camacho Rui , Silva Fernando
Published: August 2008

Inductive logic programming (ILP) is a sub‐field of machine learning that provides an excellent framework for multi‐relational data mining applications. The advantages of ILP have been successfully demonstrated in complex and relevant industrial and scientific problems. However, to produce valuable models, ILP systems often require long running times and large amounts of memory. In this paper we address fundamental issues that have direct impact on the efficiency of ILP systems. Namely, we discuss how improvements in the indexing mechanisms of an underlying logic programming system benefit ILP performance. Furthermore, we propose novel data structures to reduce memory requirements and we suggest a new lazy evaluation technique to search the hypothesis space more efficiently. These proposals have been implemented in the April ILP system and evaluated using several well‐known data sets. The results observed show significant improvements in running time without compromising the accuracy of the models generated. Indeed, the combined techniques achieve several order of magnitudes speedup in some data sets. Moreover, memory requirements are reduced in nearly half of the data sets. Copyright © 2008 John Wiley & Sons, Ltd.
ISTA13—International interlaboratory comparative evaluation of microbial assay for risk assessment (MARA)
Authors: Wadhia K.
Published: August 2008

The microbial assay for risk assessment (MARA) is an innovative system based on an array of 11 different microbial species freeze‐dried in a 96‐well micro‐titer plate. Developed for testing the toxicity of chemicals, mixtures, and environmental samples, the assay employs species of a taxonomically diverse range. In addition to 10 prokaryotic species, a eukaryote (yeast) is included in the range. The MARA's innate scope of a multi‐dimensional test allows determination of toxicity based on a unique assay fingerprint or index, numerically expressed as the mean microbial toxic concentration (MTC). The most significant potential of the test is in the additional inference that can be conveyed to the toxicity evaluation because of the presence of each of the constituent species. The performance of MARA was evaluated to ascertain its capability and potential scope in an intralaboratory trial. Sensitivity to toxicants and different environmental samples was assessed. Evaluation included comparison with other tests; namely Microtox®, invertebrate (Daphnia magna and Thamnocephalus platyurus) microbiotests, and respiration‐ and nitrification‐inhibition tests. MARA's performance was further assessed with the implementation of an international interlaboratory trial. This involved the participation of 13 laboratories ranging from academic establishments to regulatory agencies. The results of the testing will be presented with assessment of the extent of variability and specific assay components. The trial evaluation indicated that performance of the assay was satisfactory and the results were within the acceptable range. MARA is a robust multispecies assay offering scope for toxicity assessment of a diverse range of samples. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008.
Differential Dynamic Logic for Hybrid Systems
Authors: Platzer André
Published: August 2008

Hybrid systems are models for complex physical systems and are defined as dynamical systems with interacting discrete transitions and continuous evolutions along differential equations. With the goal of developing a theoretical and practical foundation for deductive verification of hybrid systems, we introduce a dynamic logic for hybrid programs, which is a program notation for hybrid systems. As a verification technique that is suitable for automation, we introduce a free variable proof calculus with a novel combination of real-valued free variables and Skolemisation for lifting quantifier elimination for real arithmetic to dynamic logic. The calculus is compositional, i.e., it reduces properties of hybrid programs to properties of their parts. Our main result proves that this calculus axiomatises the transition behaviour of hybrid systems completely relative to differential equations. In a case study with cooperating traffic agents of the European Train Control System, we further show that our calculus is well-suited for verifying realistic hybrid systems with parametric system dynamics.
Grade of adiposity affects the impact of fat mass on resting energy expenditure in women
Authors: Bosy-Westphal Anja , Müller Manfred J. , Boschmann Michael , Klaus Susanne , Kreymann Georg , Lührmann Petra M. , Neuhäuser-Berthold Monika , Noack Rudolf , Pirke Karl M. , Platte Petra , Selberg Oliver , Steiniger Jochen
Published: August 2008

Body fat mass (FM) adds to the variance in resting energy expenditure (REE). However, the nature and extent of this relationship remains unclear. Using a database of 1306 women and a linear regression model, we systematically analysed the contribution of FM to the total variance in REE at different grades of adiposity (ranges of body %FM). After adjusting for age, the relative contribution of FM on REE variance increased from low ( ≤ 10 %FM) to normal (>10– ≤ 30 %FM) and moderately elevated (>30– ≤ 40 %FM) grades of adiposity but decreased sharply at high (>40– ≤ 50 %FM) and very high (>50 %FM) grades of adiposity according to the ratio between regression coefficients. These data suggest that the specific metabolic rate of fat tissue is reduced at high adiposity. This should be considered when REE is normalized for FM in obesity.
Consumption of mate tea (Ilex paraguariensis) decreases the oxidation of unsaturated fatty acids in mouse liver
Authors: Martins Fernanda , Suzan Amanda Janaína , Cerutti Suzete Maria , Arçari Demétrius Paiva , Ribeiro Marcelo Lima , Bastos Débora Helena Markowicz , Carvalho Patrícia de Oliveira
Published: August 2008

Mate (Ilex paraguariensis) is rich in polyphenolic compounds, which are thought to contribute to the health benefits of tea. Mate tea was administered orally to mice at a dose of 0·5, 1·0 or 2·0 g/kg for 60 d, and changes both in serum lipid concentration and fatty acid composition of liver and kidney were examined. The effects of mate tea on serum and tissue lipid peroxidation were assessed by the evaluation of thiobarbituric acid-reactive substances (TBARS). In tea-consuming mice, both MUFA (18 : 1n-9) and PUFA (18 : 2n-6 and 20 : 4n-6) were increased (P < 0·05) in the liver lipid (approximately 90 and 60 %, respectively), whereas only MUFA (approximately 20 %) were increased in the kidney lipid. The most altered PUFA class wasn-6 PUFA, which increased by approximately 60–75 % (P < 0·05). This difference in the fatty acid profile in the liver is reflected in the increased PUFA:SFA ratio. Consistent with these results, mice fed with mate tea had much lower TBARS in the liver. No differences (P>0·05) were found in the levels of serum cholesterol, HDL-cholesterol and TAG under the conditions of the present study. These results suggest that treatment with mate tea was able to protect unsaturated fatty acids from oxidation and may have selective protective effects within the body, especially on the liver.
The effects of a reduced-sodium, high-potassium salt substitute on food taste and acceptability in rural northern China
Authors: Li Nicole , Prescott John , Wu Yangfeng , Barzi Federica , Yu Xuequn , Zhao Liancheng , Neal Bruce ,   for the China Salt Substitute Study Collaborative Group
Published: August 2008

A potassium chloride-containing salt substitute lowers blood pressure levels, but its overall acceptability has been of concern due to its potential adverse effects on food taste. In a large-scale, blinded randomised trial evaluating the comparative effects of a salt substitute (65 % sodium chloride, 25 % potassium chloride and 10 % magnesium sulphate) and a normal salt (100 % sodium chloride) on blood pressure, we collected data on the saltiness, flavour and overall acceptability of food. We performed this at baseline, 1, 6 and 12 months post-randomisation using 100 mm visual analogue scales for assessments of both home-cooked foods and a standard salty soup. The mean age of the 608 participants from rural northern China was 60 years and 56 % of them were females. In the primary analyses, the changes in the saltiness, flavour and overall acceptability of both home-cooked foods and a standard salty soup were not different between the randomised groups (all P>0·08). In the secondary analyses, weighting each of the data points according to the lengths of the respective follow-up intervals, the flavour of both home-cooked foods (mean difference = − 1·8 mm, P = 0·045) and a standard salty soup (mean difference = − 1·9 mm, P = 0·03) was slightly weaker in the salt substitute group. We conclude that salt substitution is both an effective and an acceptable means of blood pressure control. Possible small differences in flavour did not importantly deter the use of the salt substitute in this study group, although the acceptability of the salt substitute by a more general population group would need to be confirmed.
Effects of dietary supplementation with the green tea polyphenol epigallocatechin-3-gallate on insulin resistance and associated metabolic risk factors: randomized controlled trial
Authors: Brown A. Louise , Lane Joan , Coverly Jacqueline , Stocks Janice , Jackson Sarah , Stephen Alison , Bluck Les , Coward Andy , Hendrickx Hilde
Published: August 2008

Animal evidence indicates that green tea may modulate insulin sensitivity, with epigallocatechin-3-gallate (EGCG) proposed as a likely health-promoting component. The purpose of this study was to investigate the effect of dietary supplementation with EGCG on insulin resistance and associated metabolic risk factors in man. Overweight or obese male subjects, aged 40–65 years, were randomly assigned to take 400 mg capsules of EGCG (n46) or the placebo lactose (n42), twice daily for 8 weeks. Oral glucose tolerance testing and measurement of metabolic risk factors (BMI, waist circumference, percentage body fat, blood pressure, total cholesterol, LDL-cholesterol, HDL-cholesterol, TAG) was conducted pre- and post-intervention. Mood was evaluated weekly using the University of Wales Institute of Science and Technology mood adjective checklist. EGCG treatment had no effect on insulin sensitivity, insulin secretion or glucose tolerance but did reduce diastolic blood pressure (mean change: placebo − 0·058 (se0·75) mmHg; EGCG − 2·68 (se0·72) mmHg;P = 0·014). No significant change in the other metabolic risk factors was observed. The EGCG group also reported feeling in a more positive mood than the placebo group across the intervention period (mean score for hedonic tone: EGCG, 29·11 (se0·44); placebo, 27·84 (se0·46);P = 0·048). In conclusion, regular intake of EGCG had no effect on insulin resistance but did result in a modest reduction in diastolic blood pressure. This antihypertensive effect may contribute to some of the cardiovascular benefits associated with habitual green tea consumption. EGCG treatment also had a positive effect on mood. Further studies are needed to confirm the findings and investigate their mechanistic basis.
Pioneering American Studies: Ten Years of the Bulletin, 1956–1966
Authors: BILLINGTON LOUIS
Published: August 2008

The Bulletin of the British Association for American Studies (1956–66) provided a valuable platform for many British pioneers in the study of American history, politics and literature, and laid the ground for a more professional and permanent American studies journal when the field had become well established in this country. Here I have both attempted to analyse the Bulletin's content and commented on the professional background and intellectual interest of its contributors, including the very limited number of women whose work appeared in its pages.
AN ECONOMIC THEORISTS' READING OF SIMONE WEIL
Authors: Heifetz Aviad , Minelli Enrico
Published: August 2008

In Economics individuals are defined by their preferences over the consequences of their own actions and the actions carried out by others. In contrast, Simone Weil depicts the individual as continuously re-constituted by the contact that he establishes with reality via his action. Such an action is aimed at achieving an effect in the physical world, but what makes ithumanis not success per se, but rather the fact that it stems from reasoning and planning.Afflictionis caused by effort carried out mechanically like that of a beast of burden, when the individual has no opportunity to exercise reason for choosing how to confront reality's ever-challenging hazards andnecessity.

Simone Weil also emphasizes the importance of the socially forgedlanguagein affecting the individual's horizon and his ability to act meaningfully. In particular, foresight cannot be assumed in situations of oppression and affliction, which are extremely hard to communicate exactly because they imply an alienation between reason and action.

These observations of Simone Weil suggest new dimensions which standard economic modelling has hitherto avoided.
Generation of tropical instability waves in the Atlantic Ocean
Authors: von Schuckmann K. , Brandt P. , Eden C.
Published: August 2008

The spatial and temporal distributions of tropical instability waves (TIWs) in the Atlantic Ocean are investigated using a combination of current observations with moored instruments deployed at the equator at 23°W and a realistic eddy‐resolving (1/12°) general circulation model of the Atlantic Ocean. The meridional and vertical shears of the zonal current system contribute to the eddy production rates and thus to the generation of TIWs in the central tropical Atlantic Ocean. In the Southern Hemisphere, TIWs are forced only by baroclinic instability associated with the vertical shear of the central part of the South Equatorial Current (SEC). In the Northern Hemisphere, baroclinic instability due to the vertical shear of the northern SEC (nSEC) as well as barotropic instabilities due to horizontal shears of the Equatorial Undercurrent (EUC)/nSEC and nSEC/North Equatorial Countercurrent (NECC) contribute to the generation of the TIWs. Since seasonal changes of the instability production rates related to the EUC/nSEC are comparable low while the rates related to the nSEC/NECC are high, we suggest that the seasonality of the NECC dominates the seasonal modulation of the TIWs.
Comment on “Improving How Scientists Communicate About Climate Change”
Authors: Sedgemore Francis
Published: August 2008

In a recent issue of Eos (89(11), 11 March 2008), Susan Joy Hassol argued that climate researchers are failing in their efforts to communicate effectively with the public.

As a space physicist turned freelance journalist, I know how researchers think and act, and also how media workers function. From informal discussions with journalists, bloggers, and members of the general public, it is clear to me that the public is crying out for hard information. But people will instinctively mistrust those who feed them science‐lite.
Disentangling leaf area and environmental effects on the response of the net ecosystem CO2 exchange to diffuse radiation
Authors: Wohlfahrt Georg , Hammerle Albin , Haslwanter Alois , Bahn Michael , Tappeiner Ulrike , Cernusca Alexander
Published: August 2008

There is an ongoing discussion about why the net ecosystem CO2 exchange (NEE) of some ecosystems is less sensitive to diffuse radiation than others and about the role other environmental factors play in determining the response of NEE to diffuse radiation. Using a six‐year data set from a temperate mountain grassland in Austria we show that differences between ecosystems may be reconciled based on their green area index (GAI; square meter green plant area per square meter ground area) ‐ the sensitivity to diffuse radiation increasing with GAI. Our data suggest diffuse radiation to have a negligible influence on NEE below a GAI of 2 m2 m−2. Changes in air/soil temperature and air humidity concurrent with the fraction of diffuse radiation were found to amplify the sensitivity of the investigated temperate mountain grassland ecosystem to diffuse radiation.
Efficiency of Intermittent Exercise on Adiposity and Fatty Liver in Rats Fed With High‐fat Diet
Authors: Sene‐Fiorese Marcela , Duarte Fernanda O. , Scarmagnani Flavia R.R. , Cheik Nadia C. , Manzoni Marla S.J. , Nonaka Keico O. , Rossi Eliseu A. , De Duarte Ana C.G. Oliveira , Dâmaso Ana R.
Published: August 2008

Objective: This study aimed to examine and compare the effects of continuous or intermittent exercises on adiposity and fatty liver in rats fed with high‐fat diet.

Methods and Procedures: Wistar rats were divided according to diet composition—chow diet (C) or high‐fat diet (H)—and kinds of exercise—sedentary (S), continuous (CE), or intermittent (IE) exercises. The CE group swam 90 min/day, and the IE group swam 3 × 30 min/day (at 4‐h intervals between sessions); both groups exercised 5 days/week during 8 weeks. Body weight and food intake were recorded daily. Lipogenesis rate in vivo was determined by the incorporation of 3H2O into saponified lipids in retroperitoneal (RET), epididymal (EPI), and visceral (VIS) white adipose tissues, brown adipose tissue (BAT), liver (L), and gastrocnemius muscle (GAST) using the gravimetric method. Total cholesterol, high‐density lipoprotein (HDL)‐cholesterol, and triacylglycerol (TG) were analyzed.

Results: The major finding of this study is that IE was more efficient than CE in reducing the adverse effects of high‐fat diet and sedentarism. There was an improvement in the lipid profile and a reduction in food intake, body weight gain, visceral and central adiposity, and fatty liver, contributing to the control of obesity and other comorbidities, including nonalcoholic fat liver diseases.

Discussion: Earlier studies have discussed the effects of diet consumption on adiposity and their relation to chronic diseases and obesity. This study discusses the effects of high‐fat diet consumption and the different kinds of exercise on weight gain, adiposity, fatty liver, and lipid profile in rats. The results may depend on the exercise, time of each session, age, gender, and experimental period.
Association of ADIPOR2 With Liver Function Tests in Type 2 Diabetic Subjects
Authors: López‐Bermejo Abel , Botas‐Cervero Patricia , Ortega‐Delgado Francisco , Delgado Elías , García‐Gil Maria M. , Funahashi Tohru , Ricart Wifredo , Fernández‐Real José M.
Published: August 2008

Objective: Adiponectin protects against liver dysfunction in insulin‐resistant states such as obesity and type 2 diabetes (T2DM), but the role of adiponectin receptors in this disorder is largely unknown. We studied whether common single‐nucleotide polymorphisms (SNPs) in ADIPOR1 and ADIPOR2 are associated with liver function tests (LFTs) in human subjects with various degrees of insulin resistance.

Methods and Procedures: Serum alanine (ALT) and aspartate (AST) aminotransferases, homeostasis model assessment of insulin resistance (HOMA‐IR), −8503 G/A (rs6666089) and +5843 C/T (rs1342387) SNPs in ADIPOR1, −64,241 T/G (rs1029629) and +33447 C/T (rs1044471) SNPs in ADIPOR2 were assessed in 700 white subjects from a population‐based study.

Results: In nondiabetic subjects, the at‐risk alleles for the common −64,241 T/G and +33447 C/T SNPs in ADIPOR2 were associated with increased circulating adiponectin (P < 0.05 to P < 0.005), but not with LFT. Conversely, in T2DM subjects (who are at risk for liver dysfunction), the same alleles were associated with increased serum ALT and AST (P < 0.05 to P < 0.0001), but not with circulating adiponectin. No significant associations with these parameters were evident for the common −8503 G/A and +5843 C/T SNPs in ADIPOR1. In a replication study, the −64,241 T/G and +33447 C/T SNPs in ADIPOR2 were associated with ALT and AST (P < 0.05 to P < 0.0001) in pooled obese and T2DM subjects.

Discussion: Common SNPs in ADIPOR2 are associated with LFT in T2DM subjects, which suggests a possible role of this receptor in liver dysfunction associated with insulin resistance.
Psychiatric and Cardiovascular Comorbidities in Patients With Diabetes Mellitus Starting Antiobesity Drugs
Authors: Willemen Marjolein J. , Mantel‐Teeuwisse Aukje K. , Straus Sabine M. , Leufkens Hubert G. , Egberts Antoine C.
Published: August 2008

The aim of the study was to assess whether the baseline risk of psychiatric and cardiovascular disease in patients with diabetes mellitus differs between those starting to use antiobesity drugs and those not starting to use these drugs. A retrospective nested case‐control study within the General Practice Research Database (1987–2002) was done. The cohort included all patients with diabetes mellitus (n = 141,164). Information on patient characteristics (general, cardiovascular, and psychiatric characteristics) was extracted from the medical records. Crude odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. A total of 511 patients starting to use antiobesity drugs (cases) and 3,065 controls were included in the study cohort. Starters were younger and more frequently female. Of the starters, 91.8% did not receive any dietary advice before starting treatment. Depression (in the year before index date) was associated with the use of antiobesity drugs (OR 2.2; 95% CI 1.7–2.8), as was anxiety (OR 1.6; 95% CI 1.1–2.4). Of the cases, 25.2% had multiple cardiovascular risk factors (>4) compared to 19.0% of the controls. The baseline risk for psychiatric disorders and cardiovascular disease was found to be higher in patients with diabetes mellitus starting to use antiobesity drugs compared to patients with diabetes mellitus not starting such treatment.
Epicardial Adipose Tissue Extent: Relationship With Age, Body Fat Distribution, and Coronaropathy
Authors: Silaghi Alina , Piercecchi‐Marti Marie‐Dominique , Grino Michel , Leonetti Georges , Alessi Marie C. , Clement Karine , Dadoun Frederic , Dutour Anne
Published: August 2008

Epicardial fat is a relatively neglected component of the heart and could be an important risk factor of cardiac disease. The objective of our study was to assess the relationship between epicardial adipose tissue (EAT) extent, fat distribution, and coronaropathy in a group of adult victims of accidental or suspicious sudden death. In 56 cadavers, we performed 34 measurements of EAT from five computerized photographs of the heart (anterior and posterior faces, and three ventricle transversal slices) and analyzed their relationship with anthropometric markers of adiposity (BMI, waist and leg circumference, thickness of abdominal and thigh subcutaneous adipose tissue (SAT)), with the presence and staging of coronary artery disease (CAD), and with markers of myocardial hypertrophy. Simple linear regressions showed that EAT measurements are highly intercorrelated (r from 0.4 to 0.6, P < 0.001), and correlate with age, waist circumference, and heart weight, and to a lesser extent, with BMI, abdominal SAT thickness, and leg SAT thickness. Multiple regression showed that age, waist circumference, and heart weight significantly and independently correlate with EAT (P < 0.0001). No other anthropometric measurement was found independently correlated with EAT. The EAT/myocardium ratios correlated positively with age and waist circumference. Anterior and posterior areas of EAT were found significantly increased in patients with CAD and correlated positively with CAD staging (P = 0.0034, r = 0.38). Anterior EAT surface was found positively associated with CAD (P = 0.01), independently of age and other adiposity measurements. Prospective studies are needed to assess the risk of occurrence/progression of CAD that relate to EAT excess.
Effects on Food Intake and Blood Lipids of Cannabinoid Receptor 1 Antagonist Treatment in Lean Rats
Authors: Bennetzen Marianne F. , Nielsen Maria P. , Richelsen Bjørn , Pedersen Steen B.
Published: August 2008

Endocannabinoids act through the cannabinoid receptor 1 (CB1) and has both orexigenic and peripheral metabolic effects. It is not yet fully understood whether all the beneficial effects on the metabolic profile by CB1 antagonism are induced by the weight loss or also by direct peripheral effects. The present study was intended to further elucidate this question and to investigate whether tolerance development to the hypophagic effect could be attenuated by cyclic treatment. We performed an intervention study in 40 lean rats over 4 weeks. The rats were divided in four groups: a control group, two groups treated with the CB1 antagonist Rimonabant either continuously or cyclically, and one group pair fed with the continuous Rimonabant group to obtain the same body weight. During the first 6 days, food intake was less in the continuous Rimonabant group compared to the control group (P < 0.01). Throughout the study period, the cyclic Rimonabant group had a smaller food intake than the continuous Rimonabant group (P < 0.05). After 4 weeks, the cyclic Rimonabant group had a reduced weight gain compared to the control group (P < 0.05). Serum levels of glycerol and free fatty acids (nonesterified fatty acid, NEFA) were significantly reduced in both treated groups compared to the untreated groups, and levels of triglycerides showed the same tendency. Cyclic treatment with Rimonabant is able to inhibit tolerance development on food intake, which resulted in reduction in body weight. Rimonabant treatment is associated with reduced serum levels of glycerol, NEFA, and triglyceride which seem independent of body weight changes.
An analytical approach to computing biomolecular electrostatic potential. I. Derivation and analysis
Authors: Fenley Andrew T. , Gordon John C. , Onufriev Alexey
Published: August 2008

Analytical approximations to fundamental equations of continuum electrostatics on simple shapes can lead to computationally inexpensive prescriptions for calculating electrostatic properties of realistic molecules. Here, we derive a closed-form analytical approximation to the Poisson equation for an arbitrary distribution of point charges and a spherical dielectric boundary. The simple, parameter-free formula defines continuous electrostatic potential everywhere in space and is obtained from the exact infinite-series (Kirkwood) solution by an approximate summation method that avoids truncating the infinite series. We show that keeping all the terms proves critical for the accuracy of this approximation, which is fully controllable for the sphere. The accuracy is assessed by comparisons with the exact solution for two unit charges placed inside a spherical boundary separating the solute of dielectric 1 and the solvent of dielectric 80. The largest errors occur when the source charges are closest to the dielectric boundary and the test charge is closest to either of the sources. For the source charges placed within 2 Å from the boundary, and the test surface located on the boundary, the root-mean-square error of the approximate potential is less than 0.1 kcal/mol/|e| (per unit test charge). The maximum error is 0.4 kcal/mol/|e|. These results correspond to the simplest first-order formula. A strategy for adopting the proposed method for realistic biomolecular shapes is detailed. An extensive testing and performance analysis on real molecular structures are described in Part II that immediately follows this work as a separate publication. Part II also contains an application example.
The influence of process parameters on electromigration lifetime statistics
Authors: Hauschildt M. , Gall M. , Justison P. , Hernandez R. , Ho P. S.
Published: August 2008

Even after the successful introduction of Cu-based metallization, the electromigration failure risk has remained one of the important reliability concerns for advanced process technologies mostly due to ever increasing operating current densities. The main factors that require understanding are the activation energy related to the dominating diffusion mechanism, the median lifetimes, and the lognormal standard deviation sigma of experimentally obtained lifetime distributions. This study investigates the effect of different process parameters on electromigration lifetime statistics in Cu interconnects. First, the failure distributions of single damascene interconnects with smaller line height are examined, followed by an analysis of the influence of different passivation layers on electromigration statistics. A third part focuses on samples with dual damascene technology. It is observed that the first two process modifications change the median time to failure but do not alter the sigma value. Geometrical and kinetic models developed to describe the electromigration characteristics in Cu/SiN interconnects are successfully employed to explain this observation. These models imply that the lifetime statistics depend on variations in void sizes, geometrical and experimental factors of the electromigration test, and kinetic aspects of the mass transport process. The sigma value in dual damascene interconnects is found to be larger compared to corresponding single damascene structures as a result of an increase in possible void shapes and sizes for void growth into the via in addition to evolution along the line. Furthermore, simulations of expected characteristics of lifetime distributions for future technology nodes using the above models and current electromigration data are discussed.
Numerical assessment of local forcing on the heat transfer in a turbulent channel flow
Authors: Araya Guillermo , Leonardi Stefano , Castillo Luciano
Published: August 2008

The influence of local forcing on an incompressible turbulent channel flow is numerically investigated. The extensive information provided by the direct numerical simulations enables us to have a better understanding of the physical mechanism responsible for local heat transfer enhancement. Time-periodic blowing/suction is applied by means of thin spanwise slots located at the lower and upper walls. The molecular Prandtl number is 0.71 and the Reynolds number based on the wall friction velocity and the channel half-height, Reτ, is 394 for the unforced case. The normal perturbing velocity is varied sinusoidally in time at several perturbing frequencies between 0.16<f¯<1.6 or 0.011<f+<0.11 and at a fixed amplitude of Ao=0.2. A phase-averaging procedure is employed to discriminate between the coherent and incoherent fluctuating components. It is shown that coherent thermal fluctuations reach peak values near the forcing slot, then sharply decay and almost disappear in a short distance downstream. The incoherent thermal fluctuations also show peak values next the source; however, they decay downstream to resemble the incoherent fluctuations of the unperturbed channel. It was concluded that the forcing frequency of f¯=0.64 or f+=0.044 produced the largest local increase in the skin friction in the region 0.1<x/Lx<0.3 (where Lx is the channel length), followed by the highest augmentation of the Stanton number. It is found that augmentation of the wall shear stress fluctuations is the major cause of skin friction, wall heat flux, and Stanton number enhancement downstream from the local forcing source. On the other hand, local maxima of Reynolds shear stresses, wall-normal turbulent heat fluxes, and the incoherent component of streamwise vorticity fluctuations exhibited analogous behavior along the streamwise direction.
Effect of postannealing on the performance of pentacene single-crystal ambipolar transistors
Authors: Takenobu Taishi , Watanabe Kazuhiro , Yomogida Yohei , Shimotani Hidekazu , Iwasa Yoshihiro
Published: August 2008

Ambipolar organic field-effect transistors (OFETs) with comparable hole and electron mobilities were fabricated using pentacene single crystals. Ambipolar single-crystal transistors enable us to determine the intrinsic effect of postannealing on the performance of OFETs, which remains controversial. The results confirm that postannealing predominantly causes hole dedoping due to oxygen desorption.
High efficiency, color stability, and stable efficiency roll off in three color hybrid white organic light emitting diodes
Authors: Yook Kyoung Soo , Jeon Soon Ok , Joo Chul Woong , Lee Jun Yeob
Published: August 2008

High efficiency, good color stability, and stable efficiency roll off were achieved in three color white organic light emitting diodes by developing a device architecture with red and green phosphorescent materials codoped in a mixed host emitting structure. A fluorescent blue material was used in a blue emitting layer and a mixed interlayer structure was applied. A high quantum efficiency of 9.7% was obtained and color coordinate of (0.40, 0.40) was kept constant up to luminance of 10000cd∕m2. In addition, efficiency decrease at 10000cd∕m2 was only 2% of the maximum quantum efficiency.