bluuebunny/crossref_metadata_2025 huggingface dataset:
An outbreak of rubella in the Federation of Bosnia and Herzegovina between December 2009 and May 2010 indicates failure to vaccinate during wartime (1992–1995)
Authors: HUKIC M. , HÜBSCHEN J. M. , SEREMET M. , SALIMOVIC-BESIC I. , MULAOMEROVIC M. , MEHINOVIC N. , KARAKAS S. , CHARPENTIER E. , MULLER C. P.
Published: April 2011

A rubella outbreak involving 1900 cases was recorded in the Federation of Bosnia and Herzegovina between mid-December 2009 and the end of May 2010. Sera from 389 suspected rubella cases were examined for the presence of rubella-specific IgM and IgG antibodies. A total of 32 throat swabs from suspected rubella cases were tested by RT–PCR and were used to attempt virus isolation. Most patients (945/1900, 49·73%) had never received rubella vaccination or had an unknown vaccination status (563/1900, 29·63%). About 45% (178/389) of suspected rubella patients were IgM positive. From 13 of the throat swabs a virus isolate and E1 gene sequences attributed to genotype 2B were obtained. The rubella outbreak was due to failure to vaccinate during the war period (1992–1995) and emphasizes the need for additional vaccination opportunities.
Topics in structure-preserving discretization
Authors: Christiansen Snorre H. , Munthe-Kaas Hans Z. , Owren Brynjulf
Published: April 2011

In the last few decades the concepts of structure-preserving discretization, geometric integration and compatible discretizations have emerged as subfields in the numerical approximation of ordinary and partial differential equations. The article discusses certain selected topics within these areas; discretization techniques both in space and time are considered. Lie group integrators are discussed with particular focus on the application to partial differential equations, followed by a discussion of how time integrators can be designed to preserve first integrals in the differential equation using discrete gradients and discrete variational derivatives.

Lie group integrators depend crucially on fast and structure-preserving algorithms for computing matrix exponentials. Preservation of domain symmetries is of particular interest in the application of Lie group integrators to PDEs. The equivariance of linear operators and Fourier transforms on non-commutative groups is used to construct fast structure-preserving algorithms for computing exponentials. The theory of Weyl groups is employed in the construction of high-order spectral element discretizations, based on multivariate Chebyshev polynomials on triangles, simplexes and simplicial complexes.

The theory of mixed finite elements is developed in terms of special inverse systems of complexes of differential forms, where the inclusion of cells corresponds to pullback of forms. The theory covers, for instance, composite piecewise polynomial finite elements of variable order over polyhedral grids. Under natural algebraic and metric conditions, interpolators and smoothers are constructed, which commute with the exterior derivative and whose product is uniformly stable in Lebesgue spaces. As a consequence we obtain not only eigenpair approximation for the Hodge–Laplacian in mixed form, but also variants of Sobolev injections and translation estimates adapted to variational discretizations.
Mathematical and computational methods for semiclassical Schrödinger equations
Authors: Jin Shi , Markowich Peter , Sparber Christof
Published: April 2011

We consider time-dependent (linear and nonlinear) Schrödinger equations in a semiclassical scaling. These equations form a canonical class of (nonlinear) dispersive models whose solutions exhibit high-frequency oscillations. The design of efficient numerical methods which produce an accurate approximation of the solutions, or at least of the associated physical observables, is a formidable mathematical challenge. In this article we shall review the basic analytical methods for dealing with such equations, including WKB asymptotics, Wigner measure techniques and Gaussian beams. Moreover, we shall give an overview of the current state of the art of numerical methods (most of which are based on the described analytical techniques) for the Schrödinger equation in the semiclassical regime.
Sparse tensor discretizations of high-dimensional parametric and stochastic PDEs
Authors: Schwab Christoph , Gittelson Claude Jeffrey
Published: April 2011

Partial differential equations (PDEs) with random input data, such as random loadings and coefficients, are reformulated as parametric, deterministic PDEs on parameter spaces of high, possibly infinite dimension. Tensorized operator equations for spatial and temporalk-point correlation functions of their random solutions are derived. Parametric, deterministic PDEs for the laws of the random solutions are derived. Representations of the random solutions' laws on infinite-dimensional parameter spaces in terms of ‘generalized polynomial chaos’ (GPC) series are established. Recent results on the regularity of solutions of these parametric PDEs are presented. Convergence rates of bestN-term approximations, for adaptive stochastic Galerkin and collocation discretizations of the parametric, deterministic PDEs, are established. Sparse tensor products of hierarchical (multi-level) discretizations in physical space (and time), and GPC expansions in parameter space, are shown to converge at rates which are independent of the dimension of the parameter space. A convergence analysis of multi-level Monte Carlo (MLMC) discretizations of PDEs with random coefficients is presented. Sufficient conditions on the random inputs for superiority of sparse tensor discretizations over MLMC discretizations are established for linear elliptic, parabolic and hyperbolic PDEs with random coefficients.
Variationally consistent discretization schemes and numerical algorithms for contact problems
Authors: Wohlmuth Barbara
Published: April 2011

We consider variationally consistent discretization schemes for mechanical contact problems. Most of the results can also be applied to other variational inequalities, such as those for phase transition problems in porous media, for plasticity or for option pricing applications from finance. The starting point is to weakly incorporate the constraint into the setting and to reformulate the inequality in the displacement in terms of a saddle-point problem. Here, the Lagrange multiplier represents the surface forces, and the constraints are restricted to the boundary of the simulation domain. Having a uniform inf-sup bound, one can then establish optimal low-ordera prioriconvergence rates for the discretization error in the primal and dual variables. In addition to the abstract framework of linear saddle-point theory, complementarity terms have to be taken into account. The resulting inequality system is solved by rewriting it equivalently by means of the non-linear complementarity function as a system of equations. Although it is not differentiable in the classical sense, semi-smooth Newton methods, yielding super-linear convergence rates, can be applied and easily implemented in terms of a primal–dual active set strategy. Quite often the solution of contact problems has a low regularity, and the efficiency of the approach can be improved by using adaptive refinement techniques. Different standard types, such as residual- and equilibrated-baseda posteriorierror estimators, can be designed based on the interpretation of the dual variable as Neumann boundary condition. For the fully dynamic setting it is of interest to apply energy-preserving time-integration schemes. However, the differential algebraic character of the system can result in high oscillations if standard methods are applied. A possible remedy is to modify the fully discretized system by a local redistribution of the mass. Numerical results in two and three dimensions illustrate the wide range of possible applications and show the performance of the space discretization scheme, non-linear solver, adaptive refinement process and time integration.
Still “Plenty of Room at the Bottom” for Aberration-Corrected TEM
Authors: Jinschek Joerg R. , Yucelen Emrah , Freitag Bert , Calderon Hector A. , Steinbach Andy
Published: April 2011

In his now-famous 1959 speech on nanotechnology, Richard Feynman proposed that it should be possible to see the individual atoms in a material, if only the electron microscope could be made 100 times better. With the development of aberration correctors on transmission electron microscopes (TEMs) over the last decade, this dream of microscopists to directly image structures atom-by-atom has come close to an everyday reality. Figure 1 shows such a high-resolution transmission electron microscope (HR-TEM) image of a single-wall carbon nanotube obtained with an aberration-corrected TEM. Now that atomic-resolution images have become possible with aberration-corrector technology in both TEM and STEM, we can ask ourselves if we truly have achieved the goal of seeing individual atoms. Most aberration-corrected images exhibiting atomic resolution are not distinguishing individual atoms, but columns of a small number of atoms, so despite this remarkable achievement, there is still “plenty of room at the bottom” in order to move toward seeing, counting, and quantifying individual atoms. In fact, there never has been a more exciting time for electron microscopists.
Use of the Rise Distance Method to Measure Beam Size of a FIB
Authors: Orloff J. , Roussel L.
Published: April 2011

The performance metric of greatest interest to the user of a focused ion beam (FIB) system is generally its resolution. Because of the difficulty in defining and measuring the resolution of a FIB system directly, its performance is often assessed using a method related to the beam quality instead. This consists of the measurement of the rise distance of the beam current as the beam passes across an edge, which, for low currents where spherical aberration can be neglected, is closely related to the full width at half maximum (FWHM) of the current density of the ion beam. The edge, also known as the “knife edge,” corresponds to a sharp discontinuity in a specimen, as can be practically found on the surface of a graphite specimen. Because the rise distance can be used to obtain an idea of the dimension of the waist of a beam, it is, perhaps, an indication of the quality of an instrument. Because the rise distance depends on the quality of an edge, it is sometimes called edge sharpness. This concept bears similarities with the image sharpness method developed to assess the performance of SEMs, usually on gold nanoparticles on carbon specimen. Rise distance is actually a convolution of the current density distribution with the properties of the knife edge and depends strongly on the spatial distribution of the secondary electron yield of the edge. By using the rise distance, different systems can be compared in a quantitative way. To compare instruments, the identical specimen must be used and the measurements must be done in an identical way. This article discusses the method and some pitfalls in its application.
Nanoparticles and Public Health
Authors: Cliff Graham
Published: April 2011

I write this as a materials scientist concerned about the inadequacy of regulation, monitoring, and control of what are known as nanoparticles (NPs). This is not because present particulate legislation is “inadequate” but because it is inadequately policed and does NOT extend to small enough particulates. I have analyzed these very small particles in the analytical electron microscope (AEM) for over thirty-seven years. A graduate student, with whom I worked over thirty years ago, described in her thesis the conclusion that these particles would have “long-range environmental impact.” We did not then have the benefit of hindsight.
Pioneers in Optics: Joseph Jackson Lister and Maksymilian Pluta
Authors: Davidson Michael W.
Published: April 2011

Though microscopes and telescopes had been invented in the late sixteenth century, various optical difficulties meant that the devices were more commonly considered novelties than useful scientific instruments for many years. Chief among these problems were aberrations in the images caused by optical errors from the lenses. Many scientists had attempted to rectify such difficulties, but the nineteenth-century amateur microscopist Joseph Jackson Lister is credited with making some of the most important advances toward correcting image aberrations and establishing the microscope as a powerful means of carrying out serious scientific investigations.
Manipulating Spectra with DTSA-II
Authors: Ritchie Nicholas W. M.
Published: April 2011

The previous article in this series introduced DTSA-II and provided some background information including how to configure DTSA-II for your x-ray detector and how to read spectra from disk. This article presents more basic background material. It discusses how to display and perform basic manipulations on spectra including reading the contextual properties of spectra, visualizing spectra, labeling characteristic x-ray lines, and exporting the results as publication-quality graphics. You are encouraged to follow along using DTSA-II and example spectra, which may be downloaded for free from http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html or equivalently http://goo.gl/MI1Ku. With this background material, we will be ready to consider more sophisticated tasks like spectrum quantification and simulation in upcoming articles.
A Design-of-Experiments Approach to Characterizing Beam-Induced Deposition in the Helium Ion Microscope
Authors: Scipioni Larry , Sanford Colin , van Veldhoven Emile , Maas Diederik
Published: April 2011

Charged particle microscopes have been used extensively for the creation of nanostructures. As a subset of the techniques for this, the process of beam-induced chemistry offers almost endless flexibility for both additive (by beam-driven precursor deposition) and subtractive (by beam-catalyzed etching) processing. A recent review article makes it evident simply by its massive page count the number of materials that have been used to deposit a variety of conductive, insulating, magnetic, photonic, and other structures. To take advantage of these capabilities, though, the nanoarchitect must select the correct settings for a large number of parameters. One key figure of interest is the size of features that can be written by deposition of conducting material: how small can we go? Process development is complex, however: a standard beam-induced deposition process using the system described below calls for the control of sixteen different parameters! Several of these are used to set the flow of the reactant, several are required for defining the particle beam, and yet another set of parameters call out the routine by which the beam is scanned over the pattern of interest. In the end, the result provides just one recipe for one chemistry with one beam type. The wide scatter of reported outcomes in the review article mentioned above indicates the complexity of the problem, where each result given can be considered just a snapshot of one small corner of the parameter space. Our goal here is to apply a quantitative optimization methodology for the determination of beam chemistry processes in the helium ion microscope (HIM). In this article, we discuss efforts toward finding the minimum obtainable line width and gap width between line pairs of deposited platinum lines and giving a predictive formulation of the same.
NetNotes
Authors: Phillips Thomas E.
Published: April 2011

Selected postings from the Microscopy Listserver from January 1, 2011 to March 2, 2011. Complete listings and subscription information can be obtained at http://www.microscopy.com. Postings may have been edited to conserve space or for clarity.
‘Bad Tendencies’ in the ECtHR's ‘Hate Speech’ Jurisprudence
Authors: Sottiaux Stefan
Published: April 2011

European Court of Human Rights – Canadian Charter of Rights and Freedoms – ‘Hate speech’ – Féret – Le Pen – Keegstra – Commonalities between Canadian and ECtHR jurisprudence –Development of uniform test of incitement – Sharp distinction from US Supreme Court jurisprudence on freedom of expression
Human Rights in the EU: Rethinking the Role of the European Convention on Human Rights after Lisbon
Authors: Weiß Wolfgang
Published: April 2011

Treaty of Lisbon – Fundamental Rights Charter – European Convention on Human Rights – Partial incorporation of Convention in Charter – Incorporation of Charter into EU law with Lisbon – Questions of loss of autonomy for the EU legal order – Gain in direct effect of Convention in EU member states
Court of Justice of the European Union: Decision of 2 March 2010, Case C-315/08, Janko Rottman v. Freistaat BayernCase Note 1 Decoupling Nationality and Union Citizenship? Case Note 2 The Consequences of the Rottmann Judgment on Member State Autonomy – The European Court of Justice's Avant-Gardism in Nationality Matters
Authors: Jessurun d'Oliveira H.U. , de Groot Gerard René , Seling Anja
Published: April 2011

This reference for a preliminary ruling raises for the first time the question of the extent of the discretion available to the Member States to determine who their nationals are. In so far as citizenship of the European Union, which depends, admittedly, on enjoyment of the status of national of a Member State, is established by the Treaty, can the powers of the Member States to lay down the conditions for the acquisition and loss of nationality still be exercised without any right of supervision for Community law? That is, in essence, the point at issue in this case. This case therefore calls for clarification of the relationship between the concepts of nationality of a Member State and of citizenship of the Union, a question which, it need hardly be emphasised, to a large extent determines the nature of the European Union.
A novel LTCC differentially Fed UWB antenna for the 60 GHz band
Authors: Yang Bill , Yarovoy Alexander G. , Valavan A. Shenario Ezil , Buisman Koen , Shoykhetbrod Oleksiy
Published: April 2011

In this paper a novel differentially fed Ultra-Wide Band (UWB) antenna in low-temperature co-fired ceramics (LTCC) technology to be used in the 60 GHz band for integrated RF front-ends is presented. The antenna is based on the aperture stacked patch fed via H-shaped aperture to achieve more than 10 GHz operational bandwidth. The antenna is fed by a parallel-wire transmission line which enables the antenna to be directly integrated with differential Monolithic Microwave Integrated Circuits (MMICs). To alleviate influence of the surface waves (efficiently excited in LTCC material due to its high dielectric constant) on the antenna radiation and realize uni-directional radiation patterns, a dedicated shield is added to the antenna. The measured results of the shielded antenna showed that the antenna has an operational bandwidth from 51 GHz to over 65 GHz, the gain is about 3.5–8 dBi, and −5 dB beamwidth is about ±30°. The measurement results also demonstrated that the shield indeed improves the antenna impedance bandwidth, gain, and radiation patterns substantially.
A Typology of Caregiving Situations and Service Use in Family Carers of Older People in Six European Countries
Authors: Di Rosa Mirko , Kofahl Christopher , McKee Kevin , Bień Barbara , Lamura Giovanni , Prouskas Costis , Döhner Hanneli , Mnich Eva
Published: April 2011

This paper presents the EUROFAMCARE study findings, examining a typology of care situations for family carers of older people, and the interplay of carers with social and health services. Despite the complexity of family caregiving situations across Europe, our analyses determined the existence of seven “caregiving situations,” varying on a range of critical indicators. Our study also describes the availability and use of different support services for carers and care receivers, and carers’ preferences for the characteristics of support services. Our findings have relevance for policy initiatives in Europe, where limited resources need to be more equitably distributed and services should be targeted to caregiving situations reflecting the greatest need, and organized to reflect the preferences of family carers.
Protective Factors in Midlife
Authors: Dainese Sara M. , Allemand Mathias , Ribeiro Nadja , Bayram Sanem , Martin Mike , Ehlert Ulrike
Published: April 2011

The detection of psychological variables with a positive impact on health during middle age is of great interest. The data of 393 middle-aged participants (aged 35–45 at T1 and 45–55 at T2) of the National Survey of Midlife Development in the United States (MIDUS) were analyzed to investigate the associations between health, optimism, positive affect, social support, and a cumulative burden score. Results show a positive association of the protective factors and a predictive value of positive emotions on health over time. The burden score showed no unique association with health. Overall, the predictors explained 17% of the variance of physical health and 33% of the variance of mental health. These findings emphasize the importance of investigating protective pathways.
Liquid water content estimates using simultaneous S and Kaband radar measurements
Authors: Ellis Scott M. , Vivekanandan Jothiram
Published: April 2011

A technique for the estimation of total liquid water content (LWC; the sum of cloud water and rainwater contents) using simultaneous S and Kaband scanning radar observations is proposed and tested using the National Center for Atmospheric Research simultaneous S band and Kaband dual‐polarimetric (S‐PolKa) radar system. The sources of error for this wavelength pair are evaluated, and the methods to mitigate them are discussed. The results are LWC estimates at each radar volume that are equivalent to specifying a reflectivity (Z) – LWC relation constrained by the measured attenuation over 2 km radar ray segments. Because the radars are scanning, the LWC can be mapped out over the spatial volume and temporal evolution of the clouds. The method produces reasonable results that qualitatively compare well to in situ aircraft observations.
Reading the tea leaves of Congress
Authors: Suran Melissa
Published: April 2011

The increasing influence of the Tea Party in Congress and politics has potential repercussions for public funding of scientific research in the USA
The ribosomal protein RACK1 is required for microRNA function in both C. elegans and humans
Authors: Jannot Guillaume , Bajan Sarah , Giguère Nellie J , Bouasker Samir , Banville Isabelle H , Piquet Sandra , Hutvagner Gyorgy , Simard Martin J
Published: April 2011

Despite the importance of microRNAs (miRNAs) in gene regulation, it is unclear how the miRNA–Argonaute complex—or miRNA‐induced silencing complex (miRISC)—can regulate the translation of their targets in such diverse ways. We demonstrate here a direct interaction between the miRISC and the ribosome by showing that a constituent of the eukaryotic 40S subunit, receptor for activated C‐kinase (RACK1), is important for miRNA‐mediated gene regulation in animals. In vivo studies demonstrate that RACK1 interacts with components of the miRISC in nematodes and mammals. In both systems, the alteration of RACK1 expression alters miRNA function and impairs the association of the miRNA complex with the translating ribosomes. Our data indicate that RACK1 can contribute to the recruitment of miRISC to the site of translation, and support a post‐initiation mode of miRNA‐mediated gene repression.
Bad light stops play
Authors: Peirson Stuart N , Foster Russell G
Published: April 2011

The smooth extrapolation of results from mouse to man faces many significant obstacles, not least that humans are diurnally active primates whereas mice are nocturnally active rodents.
Subtelomeric repetitive elements determine TERRA regulation by Rap1/Rif and Rap1/Sir complexes in yeast
Authors: Iglesias Nahid , Redon Sophie , Pfeiffer Verena , Dees Martina , Lingner Joachim , Luke Brian
Published: April 2011

Telomeric repeat‐containing RNA (TERRA) has been implicated in the control of heterochromatin and telomerase. We demonstrate that yeast TERRA is regulated by telomere‐binding proteins in a chromosome‐end‐specific manner that is dependent on subtelomeric repetitive DNA elements. At telomeres that contain only X‐elements, the Rap1 carboxy‐terminal domain recruits the Sir2/3/4 and Rif1/2 complexes to repress transcription in addition to promoting Rat1‐nuclease‐dependent TERRA degradation. At telomeres that contain Y′ elements, however, Rap1 represses TERRA through recruitment of Rif1 and Rif2. Our work emphasizes the importance of subtelomeric DNA in the control of telomeric protein composition and telomere transcription.
The HARP domain dictates the annealing helicase activity of HARP/SMARCAL1
Authors: Ghosal Gargi , Yuan Jingsong , Chen Junjie
Published: April 2011

Mutations in HepA‐related protein (HARP, or SMARCAL1) cause Schimke immunoosseous dysplasia (SIOD). HARP has ATP‐dependent annealing helicase activity, which helps to stabilize stalled replication forks and facilitate DNA repair during replication. Here, we show that the conserved tandem HARP (2HP) domain dictates this annealing helicase activity. Furthermore, chimeric proteins generated by fusing the 2HP domain of HARP with the SNF2 domain of BRG1 or HELLS show annealing helicase activity in vitro and, when targeted to replication forks, mimic the functions of HARP in vivo. We propose that the HARP domain endows HARP with this ATP‐driven annealing helicase activity.
A Comparison of the Metabolic Response to Abdominal Obesity in Two Canadian Inuit and First Nations Population
Authors: Chateau‐Degat Marie‐Ludivine , Dannenbaum David A. , Egeland Grace M. , Nieboer Evert , Laouan‐Sidi Elhadji A. , Abdous Belkacem , Dewailly éric
Published: April 2011

Inuit and Cree populations are known for high obesity rates despite markedly different rates of type 2 diabetes (T2DM). To document this apparent discrepancy we evaluated the impact of body size parameters and fasting insulin (FI) on several T2DM risk factors among Inuit and Cree populations (Québec, Canada). A total of 1,104 adults (≥18 years) Inuit and Cree individuals participated in a cross‐sectional investigation. Interestingly, across both genders, across all levels of waist circumference (WC), Inuit showed lower levels of FI (age‐adjusted, P < 0.0001) and fasting glucose (P < 0.0001) than Cree individuals. In both groups, a comparison of multi‐sample structural equation models confirmed the predominant influence of WC on other traditional risk factors, compared to BMI. A preponderant direct impact of WC was observed on blood pressure (BP) parameters (P < 0.0001), high‐density lipoprotein cholesterol (HDL‐C) (P < 0.0001), and FI (P < 0.0001). Fasting glucose level appear to be influenced by WC via FI in both ethnic groups (P < 0.0001), while triacylglycerol (TAG) level was predominantly impacted by WC via FI, but only in Cree individuals (P < 0.0001). The main ethnic difference found was the strength of the impact of WC on FI, which was considerably higher among the Cree (λ = 2.4, P < 0.0001) than the Inuit (λ = 1.8, P < 0.0001). These results confirm the predominant role of abdominal adiposity in the complex and tenuous links of different traditional T2DM determinants. However, the ethnic difference in the impact of abdominal obesity on insulin levels across all WCs needs to be explored further.
A QTL for Genotype by Sex Interaction for Anthropometric Measurements in Alaskan Eskimos (GOCADAN Study) on Chromosome 19q12–13
Authors: Voruganti V. Saroja , Diego Vincent P. , Haack Karin , Cole Shelley A. , Blangero John , Göring Harald H.H. , Laston Sandra , Wenger Charlotte R. , Ebbesson Sven O.E. , Fabsitz Richard R. , Devereux Richard B. , Howard Barbara V. , Umans Jason G. , MacCluer Jean W. , Comuzzie Anthony G.
Published: April 2011

Variation in anthropometric measurements due to sexual dimorphism can be the result of genotype by sex interactions (G×S). The purpose of this study was to examine the sex‐specific genetic architecture in anthropometric measurements in Alaskan Eskimos from the Genetics of Coronary Artery Disease in Alaska Natives (GOCADAN) study. Maximum likelihood‐based variance components decomposition methods, implemented in SOLAR, were used for G×S analyses. Anthropometric measurements included BMI, waist circumference (WC), waist/height ratio, percent body fat (%BF), and subscapular and triceps skinfolds. Except for WC, mean values of all phenotypes were significantly different in men and women (P < 0.05). All anthropometric measures were significantly heritable (P < 0.001). In a preliminary analysis not allowing for G×S interaction, evidence of linkage was detected between markers D19S414 and D19S220 on chromosome 19 for WC (logarithm of odds (lod) = 3.5), %BF (lod = 1.7), BMI (lod = 2.4), waist/height ratio (lod = 2.5), subscapular (lod = 2.1), and triceps skinfolds (lod = 1.9). In subsequent analyses which allowed for G×S interaction, linkage was again found between these traits and the same two markers on chromosome 19 with significantly improved lod scores for: WC (lod = 4.5), %BF (lod = 3.8), BMI (lod = 3.5), waist/height ratio (lod = 3.2), subscapular (lod = 3.0), and triceps skinfolds (lod = 2.9). These results support the evidence of a G×S interaction in the expression of genetic effects resulting in sexual dimorphism in anthropometric phenotypes and identify the chromosome 19q12–13 region as important for adiposity‐related traits in Alaskan Eskimos.
Melanocortin Receptor 4 Deficiency Affects Body Weight Regulation, Grooming Behavior, and Substrate Preference in the Rat
Authors: Mul Joram D. , van Boxtel Ruben , Bergen Dylan J.M. , Brans Maike A.D. , Brakkee Jan H. , Toonen Pim W. , Garner Keith M. , Adan Roger A.H. , Cuppen Edwin
Published: April 2011

Obesity is caused by an imbalance between energy intake and expenditure and has become a major health‐care problem in western society. The central melanocortin system plays a crucial role in the regulation of feeding and energy expenditure, and functional loss of melanocortin receptor 4 (MC4R) is the most common genetic cause of human obesity. In this study, we present the first functional Mc4r knockout model in the rat, resulting from an N‐ethyl‐N‐nitrosourea mutagenesis–induced point mutation. In vitro observations revealed impaired membrane‐binding and subsequent nonfunctionality of the receptor, whereas in vivo observations showed that functional loss of MC4R increased body weight, food intake, white adipose mass, and changed substrate preference. In addition, intracerebroventricular (ICV) administration of Agouti‐Related Protein79–129 (AgRP79–129), an MC4R inverse agonist, or Melanotan‐II (MTII), an MC4R agonist, did affect feeding behavior in wild‐type rats but not in homozygous mutant rats, confirming complete loss of MC4R function in vivo. Finally, ICV administration of MTII induced excessive grooming behavior in wild‐type rats, whereas this effect was absent in homozygous mutant rats, indicating that MTII‐induced grooming behavior is exclusively regulated via MC4R pathways. Taken together, we expect that the MC4R rat model described here will be a valuable tool for studying monogenic obesity in humans. More specifically, the relative big size and increased cognitive capacity of rats as compared to mice will facilitate complex behavioral studies and detailed mechanistic studies regarding central function of MC4R, both of which ultimately may help to further understand the specific mechanisms that induce obesity during loss of MC4R function.
Changing BMI Categories and Healthcare Expenditures Among Elderly Medicare Beneficiaries
Authors: Wilkins Tricia Lee , Rust George S. , Sambamoorthi Usha
Published: April 2011

To examine the association between changes in BMI categories and health‐care expenditures among elderly Medicare beneficiaries using longitudinal data of the Medicare Current Beneficiary Survey (MCBS) 2000–2005. Changes in BMI were (i) Stayed Normal: individuals with a normal BMI at baseline and follow‐up; (ii) Stayed Overweight individuals with overweight BMI at baseline and follow‐up; (iii) Stayed Obese individuals with obese BMI at baseline and follow‐up; (iv) Normal‐Overweight: individuals with normal BMI at baseline and overweight BMI at follow‐up; (v) Overweight‐Obese: individuals with overweight BMI at baseline and obese BMI at follow‐up; (vi) Overweight‐Normal: individuals with overweight BMI at baseline and normal BMI at follow‐up; (vii) Obese‐Overweight: individuals with obese BMI at baseline and overweight BMI at follow‐up. Ordinary Least Squares (OLS) models on logged Year 3 expenditures were used to analyze changes in expenditures between BMI categories. Overall, 35% Stayed Normal, 34% Stayed Overweight, 18% Stayed Obese, 4% gained weight from Normal‐Overweight BMI, 3% gained weight from Overweight‐Obese BMI, 5% lost weight from Overweight‐Normal BMI, and 3% lost weight from Obese‐Overweight BMI. Adjusted models revealed those who Stayed Obese had increased total and multiple expenditure types that were significantly higher than Stayed Normal including total (11%), outpatient (25%), prescription (9%), and medical provider (4%). Compared to Stayed Normal, total expenditures were both 26% higher for Obese‐Overweight and Overweight‐Obese. The current findings highlight the importance of maintaining a normal BMI in the elderly.
Predictors of Long‐Term Weight Loss in Adults With Modest Initial Weight Loss, by Sex and Race
Authors: Svetkey Laura P. , Ard Jamy D. , Stevens Victor J. , Loria Catherine M. , Young Deb Y. , Hollis Jack F. , Appel Lawrence J. , Brantley Phillip J. , Kennedy Betty M. , Kumanyika Shiriki K. , Batch Bryan C. , Corsino Leonor , Lien Lillian F. , Vollmer William M. ,   For the Weight Loss Maintenance Collaborative Research Group
Published: April 2011

Effective weight management interventions could reduce race—sex disparities in cardiovascular disease (CVD), yet little is known about factors associated with successful weight loss maintenance in race—sex subgroups. In the Weight Loss Maintenance trial (WLM), overweight/obese (BMI 25–45 kg/m2) adults who lost ≥4 kg in a 6‐month behavioral weight loss intervention (phase I) were randomized into one of three 30‐month maintenance interventions (phase II). To investigate predictors in subgroups, randomized groups were combined for this analysis. Of 1,685 phase I participants, 1,032 (61%) entered phase II, including 12% black men (BM), 26% black women (BW), 25% white men (WM), and 37% white women (WW). Weight change over the 36‐month study ranged from −2.3% (95% confidence interval = −3.1 to −1.5%) in BW to −4.5% (95% confidence interval = −5.7 to −4.0%) in WM, the result of differential weight loss during phase I. Within race, men lost significantly more weight than women, but within sex group, weight loss did not differ significantly between races. Although participants regained weight during phase II, regain did not differ by race—sex group, and mean weight at the end of the study was significantly lower than phase I entry weight for each subgroup. In regression models, phase I weight loss predicted overall 36‐month weight loss in all race—sex groups. Healthy dietary pattern at entry, improvement in dietary pattern, or both were predictive in three of four race—sex groups. Few other variables other than initial weight loss and dietary pattern were predictive. Future research should identify additional modifiable influences on long‐term maintenance after a modest weight loss.
Blood Pressure and Heart Rate Effects, Weight Loss and Maintenance During Long‐Term Phentermine Pharmacotherapy for Obesity
Authors: Hendricks Ed J. , Greenway Frank L. , Westman Eric C. , Gupta Alok K.
Published: April 2011

There is a perception that phentermine pharmacotherapy for obesity increases blood pressure and heart rate (HR), exposing treated patients to increased cardiovascular risk. We collected data from phentermine‐treated (PT) and phentermine‐untreated (P0) patients at a private weight management practice, to examine blood pressure, HR, and weight changes. Records of 300 sequential returning patients were selected who had been treated with a low‐carbohydrate ketogenic diet if their records included complete weight, blood pressure, and HR data from seven office examinations during the first 12 weeks of therapy. The mean time in therapy, time range, and mode was 92 (97.0), 12–624, and 52 weeks. 14% were normotensive, 52% were prehypertensive, and 34% were hypertensive at their first visit or had a previous diagnosis of hypertension. PT subjects systolic blood pressure/diastolic blood pressure (SBP/DBP) declined from baseline at all data points (SBP/DBP −6.9/−5.0 mm Hg at 26, and −7.3/−5.4 at 52 weeks). P0 subjects' declines of SBP/DBP at both 26 and 52 weeks were −8.9/−6.3 but the difference from the treated cohort was not significant. HR changes in treated/untreated subjects at weeks 26 (−0.9/−3.5) and 52 (+1.2/−3.6) were not significant. Weight loss was significantly greater in the PT cohort for week 1 through 104 (P = 0.0144). These data suggest phentermine treatment for obesity does not result in increased SBP, DBP, or HR, and that weight loss assisted with phentermine treatment is associated with favorable shifts in categorical blood pressure and retardation of progression to hypertension in obese patients.
Injectorless quantum cascade lasers
Authors: Katz Simeon , Vizbaras Augustinas , Meyer Ralf , Amann Markus-Christian
Published: April 2011

This review focuses on recent progress on injectorless quantum cascade lasers, an increasingly attractive approach in comparison to the “classical” injectorbased concepts. This particularly holds for the wavelength range between 7 and 12 μm, where fundamental vibrational modes of many important molecules exist, so that sensor systems for medical, industrial and military applications highly benefit from these laser sources. The atmospheric transmission window between 8 and 12 μm, with very low damping, also enables free space applications like communication, military countermeasures, and environmental sensors. Injectorless devices operate closer to the original design principle for intersubband lasers as suggested by Suris and Kazarinov [Sov. Phys. Semicond. 5, 707 (1971)]. Therefore, a short description of their features is given in comparison to injectorbased devices. Within recent years, injectorless devices have seen rapid improvement in performance. Best injectorless devices reach threshold current densities of 450 A/cm2 at 300 K, a factor of 1.6 smaller than that for the best injectorbased devices. Their output efficiency has also increased from 2% to more than 7% within the last 2 years, reaching comparable levels and making the injectorless device concept competitive and very attractive for applications.
Transverse jet injection into a supersonic turbulent cross-flow
Authors: Rana Z. A. , Thornber B. , Drikakis D.
Published: April 2011

Jet injection into a supersonic cross-flow is a challenging fluid dynamics problem in the field of aerospace engineering which has applications as part of a rocket thrust vector control system for noise control in cavities and fuel injection in scramjet combustion chambers. Several experimental and theoretical/numerical works have been conducted to explore this flow; however, there is a dearth of literature detailing the instantaneous flow which is vital to improve the efficiency of the mixing of fluids. In this paper, a sonic jet in a Mach 1.6 free-stream is studied using a finite volume Godunov type implicit large eddy simulations technique, which employs fifth-order accurate MUSCL (Monotone Upstream-centered Schemes for Conservation Laws) scheme with modified variable extrapolation and a three-stage second-order strong-stability-preserving Runge–Kutta scheme for temporal advancement. A digital filter based turbulent inflow data generation method is implemented in order to capture the physics of the supersonic turbulent boundary layer. This paper details the averaged and instantaneous flow features including vortex structures downstream of the jet injection, along with the jet penetration, jet mixing, pressure distributions, turbulent kinetic energy, and Reynolds stresses in the downstream flow. It demonstrates that Kelvin–Helmholtz type instabilities in the upper jet shear layer are primarily responsible for mixing of the two fluids. The results are compared to experimental data and recently performed classical large eddy simulations (LES) with the same initial conditions in order to demonstrate the accuracy of the numerical methods and utility of the inflow generation method. Results here show equivalent accuracy for 1∕45th of the computational resources used in the classical LES study.
Controlling chaotic behavior of the equilibrium electrons by simultaneous using of two guiding fields in a free-electron laser with an electromagnetic-wave wiggler
Authors: Nasr N. , Mehdian H. , Hasanbeigi A.
Published: April 2011

In the present paper the effects of the combination of the axial-guide magnetic field and the ion-channel guiding on the chaotic trajectories in a free-electron laser with electromagnetic-wave wiggler have been considered. It is shown that the simultaneous using of the two guiding fields in the certain conditions causes chaotic behavior in the electron motion. It is also illustrated that the chaotic trajectories decrease as the ion-channel density or the strength of the axial magnetic field increases. The transition from the chaotic trajectories to regular trajectories, occurs at a special ion-channel density, ω−it, or a particular amount of the strength of the axial magnetic field, at. Furthermore numerically calculation shows that the normalized ion-channel frequency of the transition, ω−it, reduces by increasing the axial magnetic field. Also ω−i increase causes the trajectories to be regular at the weaker at. The electron motion has been altered significantly by the self-fields effects. It is demonstrated that, the self-fields cause a decrement in the chaotic trajectories. This is in contrast to the idealized helical wiggler FEL with the axial magnetic field guiding.
Optimal proton acceleration from lateral limited foil sections and different laser pulse durations at relativistic intensity
Authors: Toncian T. , Swantusch M. , Toncian M. , Willi O. , Andreev A. A. , Platonov K. Y.
Published: April 2011

The proton acceleration from a thin foil irradiated by a laser pulse at relativistic intensities is a process highly dependent on the electron dynamic at the rear side of the foil. By reducing the lateral size of the laser irradiated foil the hot electrons are confined in a small volume leading to an enhancement of both the maximum proton energy and the conversion efficiency in the target normal sheath acceleration regime. In this paper we demonstrate that an optimal lateral size of the target can be found. While a smaller target surface leads to a better hot electron confinement and enhances the Debye sheath accelerating the protons, it also leads to an increase of preplasma formation due to limited laser contrast available experimentally and hence to a decrease of the proton acceleration. The experimentally found optimum is in good agreement with analytic theory and 2D particle in cell simulations. In addition, the maximum proton energy as a function of pulse duration has been investigated. The experimental results fit to an analytical model.
Quasilinear theory and simulation of Buneman instability
Authors: Pavan J. , Yoon P. H. , Umeda T.
Published: April 2011

In a recently developed nonlinear theory of Buneman instability, a simplifying assumption of self-similarity was imposed for the electron distribution function, based upon which, a set of moment kinetic equations was derived and solved together with nonlinear wave kinetic equation [P. H. Yoon and T. Umeda, Phys. Plasmas 17, 112317 (2010)]. It was found that the theoretical result compared reasonably against one-dimensional electrostatic Vlasov simulation. In spite of this success, however, the simulated distribution deviated appreciably from the assumed self-similar form during the late stages of nonlinear evolution. In order to rectify this shortcoming, in this paper, the distribution function is computed on the basis of rigorous velocity space diffusion equation. A novel theoretical scheme is developed so that both the quasilinear particle diffusion equation and the adiabatic dispersion relation can be solved for an arbitrary particle distribution function. Comparison with Vlasov simulation over relatively early quasilinear phase of the instability shows a reasonable agreement, despite the fact that quasilinear theory lacks coherent nonlinear effects as well as mode–mode coupling effects.
Laser-ion acceleration through controlled surface contamination
Authors: Hou Bixue , Nees John A. , He Zhaohan , Petrov George , Davis Jack , Easter James H. , Thomas Alexander G. R. , Krushelnick Karl M.
Published: April 2011

In laser-plasma ion accelerators, control of target contamination layers can lead to selection of accelerated ion species and enhancement of acceleration. To demonstrate this, deuterons up to 75 keV are accelerated from an intense laser interaction with a glass target simply by placing 1 ml of heavy water inside the experimental chamber prior to pumping to generate a deuterated contamination layer on the target. Using the same technique with a deuterated-polystyrene-coated target also enhances deuteron yield by a factor of 3 to 5, while increasing the maximum energy of the generated deuterons to 140 keV.
A spectral method for halo particle definition in intense mismatched beams
Authors: Dorf Mikhail A. , Davidson Ronald C. , Startsev Edward A.
Published: April 2011

An advanced spectral analysis of a mismatched charged particle beam propagating through a periodic focusing transport lattice is utilized in particle-in-cell (PIC) simulations. It is found that the betatron frequency distribution function of a mismatched space-charge-dominated beam has a bump-on-tail structure attributed to the beam halo particles. Based on this observation, a new spectral method for halo particle definition is proposed that provides the opportunity to carry out a quantitative analysis of halo particle production by a beam mismatch. In addition, it is shown that the spectral analysis of the mismatch relaxation process provides important insights into the emittance growth attributed to the halo formation and the core relaxation processes. Finally, the spectral method is applied to the problem of space-charge transport limits.
Experimental realization of all-dielectric composite cubes/rods left-handed metamaterial
Authors: Wang Jun , Xu Zhuo , Yu Zhenhua , Wei Xiaoyong , Yang Yiming , Wang Jiafu , Qu Shaobo
Published: April 2011

We present a novel all-dielectric left-handed metamaterial (LHM) in the X-band microwave regime. The LHM is formed by cubes and square rods, which are made of microwave ceramic with high permittivity and low loss. Both Mie theory and dielectric resonator theory are found to play important roles in generating negative effective parameters. The effective permeability is negative in the designed frequency range due to the first Mie resonance associated with the cubes, while the effective permittivity is negative below the plasma frequency owing to the second resonance mode of the square rods. The parameter retrieval method, transmission spectra method and wedge-shaped negative refraction method are used to demonstrate that the composite has a double-negative regime. Experiments are carried out to verify the designed all-dielectric LHM. The proposed method presents new ways to realize all-dielectric LHMs.
Quality factor in clamping loss of nanocantilever resonators
Authors: Ko Jin Hwan , Jeong Joonho , Choi Jinbok , Cho Maenghyo
Published: April 2011

Clamping loss caused by elastic wave radiation to a support is one of the most dominant loss mechanisms in predicting the quality factor of very or ultra high frequency nanocantilever resonators. To consider nanosurface effects and different scales of the resonator and support, we propose a multiscale model combining a scale-bridging model for the resonator and a perfectly matched layer to estimate the loss in the support. The proposed model is used to investigate the surface effect on the nanoresonator and also shows the tradeoff between the resonant frequency and the quality factor with or without the surface effects.