bluuebunny/crossref_metadata_2025 huggingface dataset:
The COgnitive-Pulmonary Disease (COgnitive-PD) study: protocol of a longitudinal observational comparative study on neuropsychological functioning of patients with COPD
Authors: Cleutjens Fiona A H M , Wouters Emiel F M , Dijkstra Jeanette B , Spruit Martijn A , Franssen Frits M E , Vanfleteren Lowie E G W , Ponds Rudolf W H M , Janssen Daisy J A
Published: March 2014

Introduction

Intact cognitive functioning is necessary for patients with chronic obstructive pulmonary disease (COPD) to understand the value of healthy lifestyle guidelines, to make informed decisions and subsequently act on it. Nevertheless, brain abnormalities and cognitive impairment have been found in patients with COPD. To date, it remains unknown which cognitive domains are affected and what the possible consequences are of cognitive impairment. Therefore, objectives of the study described are to determine neuropsychological functioning in patients with COPD, and its influence on health status, daily functioning and pulmonary rehabilitation outcome. Furthermore, structural and functional brain abnormalities and the relationship with cognitive and daily functioning will be explored.

Methods and analysis

A longitudinal observational comparative study will be performed in 183 patients with COPD referred for pulmonary rehabilitation and in 90 healthy control participants. Demographic and clinical characteristics, activities of daily living and knowledge about COPD will be assessed. Baseline cognitive functioning will be compared between patients and controls using a detailed neuropsychological testing battery. An MRI substudy will be performed to compare brain abnormalities between 35 patients with COPD with cognitive impairment and 35 patients with COPD without cognitive impairment. Patients will be recruited between November 2013 and November 2015.

Ethics and dissemination

The study has been approved by the Medical Ethics Committee of the University Hospital Maastricht and Maastricht University (NL45127.068.13/METC 13-3-035) and is registered in the Dutch trial register. All participants will provide written informed consent and can withdraw from the study at any point in time. Assessment and home visit data material will be managed anonymously. The results obtained can be used to optimise patient-oriented treatment for cognitively impaired patients with COPD. The findings will be disseminated in international peer-reviewed journals and through research conferences.
A guide to understanding polycystic ovary syndrome (PCOS)
Authors: Duncan W Colin
Published: March 2014

Polycystic ovary syndrome (PCOS) is the commonest endocrine disorder affecting women of reproductive age. Some 20% of women will have polycystic ovaries on an ultrasound scan and around 7% of women have the additional clinical or biochemical features of PCOS. As a complex multisystem disorder its background can be confusing to understand. They key feature, however, is an increased production of androgen by the ovaries. This review uses ovarian biology to describe a strategy to aid understanding and explanation of PCOS. This framework can be also be used to teach about PCOS and to inform different approaches to its management.
Development of a low‐dose fast‐dissolving tablet formulation of Newcastle disease vaccine for low‐cost backyard poultry immunisation
Authors: Lal M. , Zhu C. , McClurkan C. , Koelle D. M. , Miller P. , Afonso C. , Donadeu M. , Dungu B. , Chen D.
Published: March 2014

The immunisation of backyard poultry is critical for maintaining healthy flocks to provide nutrition and income for low‐resource farmers worldwide. A vaccine presentation for flocks of less than 50 birds could make it more affordable and accessible, increasing uptake and impact. Fast‐dissolving tablets (FDT) of Newcastle disease virus (NDV) vaccine were produced by freeze drying the LaSota NDV strain combined with excipients into tablets containing a small number of doses and packaged in polymer blister sheets. The NDV‐FDT vaccine maintained virus stability for more than six months at 4°C, based on plaque assay and egg infectivity dose data. Stability was further confirmed in a challenge study, where the tablet vaccine elicited a strong immune response and provided 100 per cent protection to vaccinated chickens infected with a virulent strain of NDV. The vaccine tablet can be diluted in water (no needle or syringe required) and administered either in drinking water or with a dropper via an intraocular and/or intransal route. Results indicate that FDTs containing a small number of doses are a feasible presentation for backyard poultry farmers. The compact packaging of the FDTs will also provide cost savings in storing and distributing the vaccine in the cold chain.
Origin of porcine circovirus type 2 (PCV2) from swine affected by PCV2‐associated diseases in Croatia
Authors: Novosel D. , Tuboly T. , Csagola A. , Lorincz M. , Cubric‐Curik V. , Jungic A. , Curik I. , Segalés J. , Cortey M. , Lipej Z.
Published: March 2014

Porcine circovirus type 2 (PCV2) causes some of the most significant economic losses in pig production. Several multisystemic syndromes have been attributed to PCV2 infection, which are known as PCV2‐associated diseases (PCVDs). This study investigated the origin and evolution of PCV2 sequences in domestic pigs and wild boars affected by PCVDs in Croatia. Viral sequences were recovered from three wild boars diagnosed with PCV2‐systemic disease (PCV2‐SD), 63 fetuses positive for PCV2 DNA as determined by PCR, 14 domestic pigs affected with PCV2‐SD (displaying severe interstitial nephritis) and five domestic pigs with proliferative and necrotising pneumonia. Seventeen complete PCV2 genomes were recovered. Phylogenetic and evolutionary analyses based on median‐joining phylogenetic networks, amino acid alignments and principal coordinate analysis were performed using complete genomes, as well as complete and partial ORF sequences for ORF1 and ORF2. Two of the 17 PCV2 sequences belonged to PCV2a, 14 to PCV2b and one was unclustered. PCV2b was the predominant genotype in Croatia and has been linked to international trade as a route of introduction. Correlation between particular viral strains with PCVDs is lacking.
John Tuzo Wilson: a Canadian who revolutionized Earth Sciences
Authors: Polat Ali
Published: March 2014

John Tuzo Wilson (1908–1993) was one of the greatest Canadian scientists of the 20th century. His contributions to Earth Sciences, leading the formulation of the theory of plate tectonics, have revolutionized our understanding of how the planet Earth works and evolved over the past 4 billion years. This 50th anniversary special issue of the Canadian Journal of Earth Sciences is dedicated in honour of John Tuzo Wilson, who inspired tens of thousands of students all around the world to study the Earth. This special issue contains 12 papers dealing with various aspects of the “Wilson Cycle” in the geologic record, plate tectonics, mantle plumes, and how John Tuzo Wilson accepted “continental drift” and formulated the theory of plate tectonics. The contributions have mostly been made by geoscientists who directly or indirectly associated with John Tuzo Wilson and have contributed significantly to the plate tectonics paradigm.
Animal perception in gravel-bed rivers: scales of sensing and environmental controls on sensory information
Authors: Johnson Matthew F. , Rice Stephen P.
Published: March 2014

Animals make decisions based on the sensory information that they obtain from the environment and other organisms within that environment. In a river, this information is transported, transmitted, masked, and filtered by fluvial factors and processes, such as relative roughness and turbulent flow. By interpreting the resultant signals, animals decide on the suitability of habitat and their reaction to other organisms. While a great deal is known about the sensory biology of animals, only limited attention has been paid to the environmental controls on the propagation of sensory information within rivers. Here, the potential transport mechanisms and masking processes of the sensory information used by animals in gravel-bed rivers are assessed by considering how the physical nature of sensory signals are affected by river hydromorphology. In addition, the physical processes that animals have the potential to directly perceive are discussed. Understanding the environmental phenomena that animals directly perceive will substantially improve understanding of what controls animal distributions, shifting emphasis from identifying correlations between biotic and abiotic factors to a better appreciation of causation, with benefits for successful management.
Grass carp in the Great Lakes region: establishment potential, expert perceptions, and re-evaluation of experimental evidence of ecological impact
Authors: Wittmann Marion E. , Jerde Christopher L. , Howeth Jennifer G. , Maher Sean P. , Deines Andrew M. , Jenkins Jill A. , Whitledge Gregory W. , Burbank Sarah R. , Chadderton William L. , Mahon Andrew R. , Tyson Jeffrey T. , Gantz Crysta A. , Keller Reuben P. , Drake John M. , Lodge David M.
Published: March 2014

Intentional introductions of nonindigenous fishes are increasing globally. While benefits of these introductions are easily quantified, assessments to understand the negative impacts to ecosystems are often difficult, incomplete, or absent. Grass carp (Ctenopharyngodon idella) was originally introduced to the United States as a biocontrol agent, and recent observations of wild, diploid individuals in the Great Lakes basin have spurred interest in re-evaluating its ecological risk. Here, we evaluate the ecological impact of grass carp using expert opinion and a suite of the most up-to-date analytical tools and data (ploidy assessment, eDNA surveillance, species distribution models (SDMs), and meta-analysis). The perceived ecological impact of grass carp by fisheries experts was variable, ranging from unknown to very high. Wild-caught triploid and diploid individuals occurred in multiple Great Lakes waterways, and eDNA surveillance suggests that grass carp are abundant in a major tributary of Lake Michigan. SDMs predicted suitable grass carp climate occurs in all Great Lakes. Meta-analysis showed that grass carp introductions impact both water quality and biota. Novel findings based on updated ecological impact assessment tools indicate that iterative risk assessment of introduced fishes may be warranted.
How variable is recruitment for exploited marine fishes? A hierarchical model for testing life history theory
Authors: Thorson James T. , Jensen Olaf P. , Zipkin Elise F.
Published: March 2014

Recruitment often varies substantially in fish populations, and residual variability may have serial autocorrelation due to environmental effects even after accounting for a stock–recruitment relationship. However, the likely magnitude of variability and autocorrelation in recruitment has yet to be formally estimated. We therefore developed a hierarchical model for recruitment variability and autocorrelation and applied it to data for 154 fish populations. Results were similar when using either the Ricker or Beverton–Holt stock–recruitment model, and showed that autocorrelated recruitment has a marginal standard deviation of 0.74 (SD = 0.35) and a mean autocorrelation of 0.43 (SD = 0.28) when predicting for an unobserved taxonomic order. Estimates differed somewhat among taxonomic orders and stocks, and also supported a hypothesized positive relationship between age at maturity and autocorrelation in recruitment. Our results can be used as a Bayesian prior for recruitment variability in models for data-poor stocks and to distinguish recruitment from other process errors in models for data-rich stocks. Estimates can also be used in the design of future simulation models and management strategy evaluations and in theoretical research regarding life history variation.
Dietary dependence of Williamson’s Sapsucker nestlings on ants associated with dead and decaying wood in British Columbia
Authors: Gyug Les W. , Higgins Robert J. , Todd Melissa A. , Meggs Jeff M. , Lindgren B. Staffan
Published: March 2014

Williamson’s Sapsucker (Sphyrapicus thyroideus (Cassin, 1852)) breeds primarily in managed forests in Canada. Its status as endangered will require reliable information to develop habitat management guidelines. Adults provision nestlings with ants gleaned from tree trunks, so we estimated the preferred nestling diet by comparing nestling fecal sac composition with the ant fauna collected in tree trunk traps. For ants, we determined nest densities and substrates by counts along transects within sapsucker nest areas. Ants made up 98% of >10 000 arthropods identified in Williamson’s Sapsucker fecal sacs. Of 11 ant taxa available, Williamson’s Sapsucker consumed six, of which two large-bodied ant taxa, carpenter ants of Camponotus subgenus Camponotus and ants of the Formica rufa species group, were preferred. Together these two taxa averaged 80% of the nestling diet by biomass and formed >48% of the nestling diet at every nest examined (n = 89). Preference varied regionally: west of the Okanagan Valley, only the two large-bodied ant taxa already mentioned were preferred, in the Okanagan–Boundary and East Kootenay regions, smaller bodied ants of the genus Lasius were also preferred, although these comprised ≤5% of the nestling diet by biomass. Camponotus (Camponotus) spp. nests were 3.3 times more common in wood than soil, and the F. rufa species group were entirely dependent on dead or decaying wood for nest substrate. Given the dependence of Williamson’s Sapsucker on these ants, retention and recruitment of dead and decaying wood should be considered a management priority for Williamson’s Sapsucker breeding habitat.
Developing generalized, calibratable, mixed-effects meta-models for large-scale biomass prediction
Authors: de-Miguel Sergio , Mehtätalo Lauri , Durkaya Ali
Published: March 2014

Large-scale prediction of forest biomass is of interest for forest science, ecology, and issues related to climate change. Previous research has attempted to provide allometric models suitable for large-scale biomass prediction using different methods. We present a new approach for meta-analysis of existing biomass equations using mixed-effects modelling on simulated data. The resulting generalized meta-models can be calibrated for local conditions. This meta-analytical approach allows for directly benefiting from previous research to minimize data collection and properly take into account the unknown differences between different locations within large areas. The approach is demonstrated by developing pan-Mediterranean mixed-effects meta-models for Pinus brutia Ten. The fixed part of the meta-models enables sound aboveground biomass predictions throughout practically the full native range of the species. Significant improvement in the predictive performance can be further gained by using small local datasets for model calibration. The calibration procedure for location-specific biomass prediction is based on best linear unbiased predictor of random effects. The predictive performance of the meta-models under different sampling strategies is validated in an independent dataset. The results show that mixed-effects meta-models may enable accurate and robust large-scale biomass predictions. Calibration for specific locations based on minimal data collection effort performs better than fitting location-specific equations based on much larger samples. The advantages of mixed-effects meta-models are of interest not only for further biomass-related research and applications, but also for other modelling disciplines within forest science.
How to improve allometric equations to estimate forest biomass stocks? Some hints from a central African forest
Authors: Moundounga Mavouroulou Quentin , Ngomanda Alfred , Engone Obiang Nestor Laurier , Lebamba Judicaël , Gomat Hugues , Mankou Géraud Sidoine , Loumeto Joël , Midoko Iponga Donald , Kossi Ditsouga Franck , Zinga Koumba Roland , Botsika Bobé Karl Henga , Lépengué Nicaise , Mbatchi Bertrand , Picard Nicolas
Published: March 2014

Predicting the biomass of a forest stand using forest inventory data and allometric equations involves a chain of propagation of errors going from the sampling error to the tree measurement error. Using a biomass data set of 101 trees in a tropical rain forest in Gabon, we compared two sources of error: the error due to the choice of allometric equation, assessed using Bayesian model averaging, and the biomass measurement error when tree biomass is calculated from tree volume rather than directly weighed. Differences between allometric equations resulted in a between-equation error of about 0.245 for log-transformed biomass compared with a residual within-equation error of 0.297. Because the residual error is leveled off when randomly accumulating trees whereas the between-equation error is incompressible, the latter turned out to be a major source of error at the scale of a 1 ha plot. Measuring volumes rather than masses resulted in an error of 0.241 for log-transformed biomass and an average overestimation of the biomass by 19%. These results confirmed the choice of the allometric equation as a major source of error but unexpectedly showed that measuring volumes could seriously bias biomass estimates.
p- and n-type microcrystalline silicon oxide (μc-SiOx:H) for applications in thin film silicon tandem solar cells
Authors: Smirnov V. , Lambertz A. , Tillmanns S. , Finger F.
Published: March 2014

We report on the development and application of p- and n-type hydrogenated microcrystalline silicon oxide (μc-SiOx:H) alloys in tandem thin film silicon solar cells. Our results show that the optical, electrical, and structural properties of μc-SiOx:H can be conveniently tuned over a wide range to fulfil the requirements for solar cell applications. We have shown that adding of PH3 gas during deposition tends to increase crystallinity of μc-SiOx:H layers, while additional trimethylboron (TMB) tends to suppress crystalline growth. When applied in tandem solar cells, both p- and n-type μc-SiOx:H lead to a remarkable increase in the top cell current. Taking advantage of low refractive index and high optical band gap of μc-SiOx:H allows the achievement of high efficiencies of 13.1% (initial) and 11.8% (stabilized).
Atorvastatin increases endothelial progenitor cells in balloon-injured mouse carotid artery
Authors: Zhou Jianpo , Chen Lei , Fan Yiling , Jiang Jiyao , Wan Jieqing
Published: March 2014

Here we aimed to investigate the effects of atorvastatin on accelerated reendothelialization after carotid balloon injury. A mouse model of carotid arterial injury was established, followed by intragastric administration of atorvastatin at a dose of 0.6 mg·(kg body mass)–1·d–1. Pathological sections of carotid artery stained with hematoxylin and eosin were observed under light microscopy. Expression levels of eNOS mRNA and protein were detected with real-time quantitative PCR and Western blot analysis, respectively. Proliferation and differentiation of endothelial progenitor cells (EPCs) were observed after treatment, in vitro. Reendothelialization appeared on the neovascular surface, while intimal hyperplasia was inhibited after treatment with atorvastatin. Numbers of CD31-positive cells increased after atorvastatin treatment, as did the number of leucocyte antigen positive cells. The expression of cell markers, such as CD34, eNOS, and VEGF-R, were higher in the atorvastatin-treated group of mononuclear cells. EPC numbers increased with the concentration of atorvastatin. The expression of eNOS mRNA was reduced in the mice with carotid artery injury that were treated with normal saline. The expression levels of eNOS protein were increased in atorvastatin treatment group. In conclusion, atorvastatin stimulates EPCs to differentiate into endothelial cells and promotes the repair of carotid arterial injury.
Fluoxetine treatment of rat neonates significantly reduces oxidative stress in the hippocampus and in behavioral indicators of anxiety later in postnatal life
Authors: da Silva Aline Isabel , Monteiro Galindo Ligia Cristina , Nascimento Luciana , Moura Freitas Cristiane , Manhaes-de-Castro Raul , Lagranha Claudia Jacques , Lopes de Souza Sandra
Published: March 2014

The brain, more than any other organ in the body, is vulnerable to oxidative stress damage, owing to its requirement for high levels of oxygenation. This is needed to fulfill its metabolic needs in the face of relatively low levels of protective antioxidants. Recent studies have suggested that oxidative stress is directly involved in the etiology of both eating and anxiety behavior. The aim of this study was to evaluate the effect of fluoxetine-inhibited serotonin reuptake in nursing rat neonates on behavior and on oxidative stress in the hypothalamus and the hippocampus; brain areas responsible for behavior related to food and anxiety, respectively. The results show that increased serotonin levels during a critical period of development do not induce significant differences in food-related behavior (intake and satiety), but do result in a in a significant decrease in anxiety. Measurements of oxidative stress showed a significant reduction of lipid peroxidation in the hippocampus (57%). In the hypothalamus, antioxidant enzymes were unchanged, but in the hippocampus, the activity of catalase and glutathione-S-transferase was increased (80% and 85% respectively). This suggests that protecting neural cells from oxidative stress during brain development contributes to the anxiolytic effects of serotonin.
Vector bundles on Fano threefolds of genus 7 and Brill–Noether loci
Authors: Brambilla Maria Chiara , Faenzi Daniele
Published: March 2014

Let X be a smooth prime Fano threefold of genus 7 and let Γ be its homologically projectively dual curve. We prove that, for d ≥ 6, an irreducible component of the moduli scheme MX(2, 1, d) of rank-2 stable sheaves on X with c1= 1, c2= d is birational to a generically smooth (2d - 9)-dimensional component of the Brill–Noether variety [Formula: see text] of stable vector bundles on Γ of rank d - 5 and degree 5d-24 with at least 2d - 10 independent global sections. The space MX(2, 1, 6) is proved to be isomorphic to [Formula: see text], and to be a smooth irreducible threefold if X is general enough.
Exponential dichotomies with respect to a sequence of norms and admissibility
Authors: Barreira Luis , Dragičević Davor , Valls Claudia
Published: March 2014

For a nonautonomous dynamics defined by a sequence of linear operators, we introduce the notion of an exponential dichotomy with respect to a sequence of norms and we characterize it completely in terms of the admissibility in lp spaces, both for the space of perturbations and the space of solutions. This allows unifying the notions of uniform and nonuniform exponential behavior. Moreover, we consider the general case of a noninvertible dynamics. As a nontrivial application we show that the conditional stability of a nonuniform exponential dichotomy persists under sufficiently small linear perturbations.
On the Bergman metric on bounded pseudoconvex domains an approach without the Neumann operator
Authors: Herbort Gregor
Published: March 2014

Let 0 < ε ≤ ½ be fixed. We prove that on a bounded pseudoconvex domain D ⋐ ℂn the Bergman metric grows at least like [Formula: see text] times the euclidean metric, provided that on D there exists a family (φδ)δ of smooth plurisubharmonic functions with a self-bounded complex gradient (uniformly in δ), such that for any δ the Levi form of φδ has eigenvalues ≥ δ-2ε on the set {z ∈ D | δD(z) < δ}. Here, δD denotes the boundary-distance function on D.
On 3-dimensional homotopy quantum field theory II: The surgery approach
Authors: Turaev Vladimir , Virelizier Alexis
Published: March 2014

Homotopy Quantum Field Theories (HQFTs) generalize more familiar Topological Quantum Field Theories (TQFTs). In generalization of the surgery construction of 3-dimensional TQFTs from modular categories, we use surgery to derive 3-dimensional HQFTs from G-modular categories.
THERMODYNAMIC LIMIT IN STATISTICAL PHYSICS
Authors: KUZEMSKY A. L.
Published: March 2014

The thermodynamic limit in statistical thermodynamics of many-particle systems is an important but often overlooked issue in the various applied studies of condensed matter physics. To settle this issue, we review tersely the past and present disposition of thermodynamic limiting procedure in the structure of the contemporary statistical mechanics and our current understanding of this problem. We pick out the ingenious approach by Bogoliubov, who developed a general formalism for establishing the limiting distribution functions in the form of formal series in powers of the density. In that study, he outlined the method of justification of the thermodynamic limit when he derived the generalized Boltzmann equations. To enrich and to weave our discussion, we take this opportunity to give a brief survey of the closely related problems, such as the equipartition of energy and the equivalence and nonequivalence of statistical ensembles. The validity of the equipartition of energy permits one to decide what are the boundaries of applicability of statistical mechanics. The major aim of this work is to provide a better qualitative understanding of the physical significance of the thermodynamic limit in modern statistical physics of the infinite and "small" many-particle systems.
On the moment system and a flexible Prandtl number
Authors: Machado Raúl
Published: March 2014

The Maxwell–Boltzmann moment system can be seen as a particular case of a mathematically more general moment system proposed by Machado.1These last moments, of which a suggested continuous distribution and an integral generating form are presented here for some orders, are used in this paper to theoretically show (one of) their usefulness: A flexible Prandtl number can be obtained in both the Boltzmann equation and in the lattice Boltzmann equation with a conventional single relaxation time Bhatnagar–Gross–Krook (BGK) collision model.
A NEW SIMPLE HYPERBOLIC SHEAR DEFORMATION THEORY FOR FUNCTIONALLY GRADED PLATES RESTING ON WINKLER–PASTERNAK ELASTIC FOUNDATIONS
Authors: SAID ABDERRAHMANE , AMEUR MOHAMMED , BOUSAHLA ABDELMOUMEN ANIS , TOUNSI ABDELOUAHED
Published: March 2014

An improved simple hyperbolic shear deformation theory involving only four unknown functions, as against five functions in case of first or other higher-order shear deformation theories, is introduced for the analysis of functionally graded plates resting on a Winkler–Pasternak elastic foundation. The governing equations are derived by employing the principle of virtual work and the physical neutral surface concept. The accuracy of the present analysis is demonstrated by comparing some of the present results with those of the classical, the first-order and the other higher-order theories.
Lightlike flat geometry of spacelike submanifolds in Lorentz–Minkowski space
Authors: Izumiya Shyuichi , Kasedou Masaki
Published: March 2014

In this paper, we investigate differential geometry on spacelike submanifolds in Lorentz–Minkowski space from the viewpoint of contact with lightlike hyperplanes. It is called the lightlike flat geometry which has been well established for the codimension-two case. In order to develop the theory for the general codimension-case, we introduce the notion of codimension-two spacelike canal submanifolds which is a main tool in this paper. We apply the theory of Lagrangian/Legendrian singularities to codimension-two spacelike canal submanifolds and obtain the relation with the previous results on the codimension-two case.
Hamiltonian expression of curvature tensors in the York canonical basis: (I) Riemann tensor and Ricci scalars
Authors: Lusanna Luca , Villani Mattia
Published: March 2014

By using the York canonical basis of ADM tetrad gravity, in a formulation using radar 4-coordinates for the parametrization of the 3+1 splitting of the space-time, it is possible to write the 4-Riemann tensor of a globally hyperbolic, asymptotically Minkowskian space-time as a Hamiltonian tensor, whose components are 4-scalars with respect to the ordinary world 4-coordinates, plus terms vanishing due to Einstein's equations. Therefore, "on-shell" we find the expression of the Hamiltonian 4-Riemann tensor. Moreover, the 3+1 splitting of the space-time used to define the phase space allows us to introduce a Hamiltonian set of null tetrads and to find the Hamiltonian expression of the 4-Ricci scalars of the Newman–Penrose formalism. This material will be used in the second paper to study the 4-Weyl tensor, the 4-Weyl scalars and the 4-Weyl eigenvalues and to clarify the notions of Dirac and Bergmann observables.
Hamiltonian expression of curvature tensors in the York canonical basis: (II) Weyl tensor, Weyl scalars, Weyl eigenvalues and the problem of the observables of the gravitational field
Authors: Lusanna Luca , Villani Mattia
Published: March 2014

We find the Hamiltonian expression in the York basis of canonical ADM tetrad gravity of the 4-Weyl tensor of the asymptotically Minkowskian space-time. Like for the 4-Riemann tensor we find a radar tensor (whose components are 4-scalars due to the use of radar 4-coordinates), which coincides with the 4-Weyl tensor on-shell on the solutions of Einstein's equations. Then, by using the Hamiltonian null tetrads, we find the Hamiltonian expression of the Weyl scalars of the Newman–Penrose approach and of the four eigenvalues of the 4-Weyl tensor. After having introduced the Dirac observables (DOs) of canonical gravity, whose determination requires the solution of the super-Hamiltonian and super-momentum constraints, we discuss the connection of the DOs with the notion of 4-scalar Bergmann observables (BOs). Due to the use of radar 4-coordinates these two types of observables coincide in our formulation of canonical ADM tetrad gravity. However, contrary to Bergmann proposal, the Weyl eigenvalues are shown not to be BOs, so that their relevance is only in their use (first suggested by Bergmann and Komar) for giving a physical identification as point-events of the mathematical points of the space-time 4-manifold. Finally we give the expression of the Weyl scalars in the Hamiltonian post-Minkowskian linearization of canonical ADM tetrad gravity in the family of (non-harmonic) 3-orthogonal Schwinger time gauges.
Enhanced photocatalytic ability from carbon-doped ZnO photocatalyst synthesized without an external carbon precursor
Authors: Zhang Dong En , Wang Ming Yan , Ma Juan Juan , Han Gui Quan , Li Shu An , Zhao Hong , Zhao Bin Yuan , Tong Zhi Wei
Published: March 2014

We report a simple synthesis of C -doped ZnO composite nanoparticles by a solvothermal treatment of Zn ( OAc )2 ⋅ 2 H 2 O that provides a source of both zinc and carbon. The photocatalytic activities of the composites were evaluated by the degree of degradation rhodamine B in aqueous solutions at room temperature with near UV light irradiation. These nanocomposites exhibit higher photocatalytic activity compared with pure ZnO nanoparticles. The enhancement of photocatalytic activity of C -doped ZnO nanoparticles is mainly attributed to their absorbed more photons and reduced electron hole pair recombination.
Natural diatomite modified as novel hydrogen storage material
Authors: Jin Jiao , Zheng Chenghui , Yang Huaming
Published: March 2014

Natural diatomite, subjected to different modifications, is investigated for hydrogen adsorption capacities at room temperature. An effective metal-modified strategy is developed to disperse platinum ( Pt ) and palladium ( Pd ) nanoparticles on the surface of diatomite. Hydrogen adsorption capacity of pristine diatomite (diatomite) is 0.463 wt.% at 2.63 MPa and 298 K, among the highest of the known sorbents, while that of acid-thermally activated diatomite (A-diatomite) could reach up to 0.833 wt.% due to the appropriate pore properties by activation. By incorporation with a small amount of Pt and Pd (~0.5 wt.%), hydrogen adsorption capacities are enhanced to 0.696 wt.% and 0.980 wt.%, respectively, indicating that activated diatomite shows interesting application in the field of hydrogen storage at room temperature.
Enhancing the efficiency of wastewater treatment by addition of Fe-based amorphous alloy powders with H2O2 in ferrofluid
Authors: Yang Chun-Cheng , Bian Xiu-Fang , Yang Jian-Fei
Published: March 2014

Using combination of ferrofluid (FF) and Fe -based amorphous alloy in the advanced treatment of high concentration, organic wastewater was investigated. The addition of Fe 73.5 Nb 3 Cu 1 Si 13.5 B 9 amorphous alloy powders into a FF give rise to a dramatic enhancement in decreasing chemical oxygen demand (COD) and decolorization. The removal rate of COD by using FF that combined Fe 73.5 Nb 3 Cu 1 Si 13.5 B 9 metallic glass (MG) particles reached 92% in the presence of H 2 O 2, nearly more than 50% higher than that by using only FF. Furthermore, compared with the FF, the decolorizing effect of the combination was 20% higher. It has been found that MG powders with the amorphous structures have high efficiency of waste water treatment and lead to high catalytic ability.
Preparation and gas sensing property of Ag-supported vanadium oxide nanotubes
Authors: Jin Wei , Yan Shilin , Chen Wen , Yang Shuang , Zhao Chunxia , Dai Ying
Published: March 2014

A facile microwave irradiation was used to synthesize Ag nanoparticle supported on vanadium oxide nanotubes (VONTs) in this paper. The VONTs on alumina tube installed with Pt electrodes were tested for gas sensing towards C 2 H 5 OH , NH 3 and C 6 H 5 CH 3 gases. Detailed studies showed that the sensing capabilities were greatly enhanced in comparison to those of pure nanotubes. It was found that the Ag nanoparticles supported on VONTs sensing films exhibited a high C 2 H 5 OH selectivity compared with NH 3 and C 6 H 5 CH 3 gases. When the sensor is exposed to C 2 H 5 OH , the ethanol molecules interact with the preadsorbed oxygen ions on the Ag nanoparticles surface. The ethanol oxidation on the Ag nanoparticles leads to the transfer of electrons into the semiconducting VONTs and this is reflected as the change in conductance of sensor. The presence of Ag nanoparticles on the surface of VONTs serves to enhance the C 2 H 5 OH oxidation due to a higher oxygen ion-chemisorption on the conductive Ag nanoparticle surfaces.
Can Science Fiction Ever Get the Science Right?
Authors: BBC News
Published: March 2014

New film Gravity promises to rekindle the debate over how "hard" — or accurate-science fiction should be. Should film-makers adhere to basic scientific principles, or should audiences just feel the magic instead, asks Peter Ray Allison.
Notes on the Writing of Scientific English for Japanese Physicists
Authors: Leggett Anthony J.
Published: March 2014

The main guiding principles I have used are the following. First, it is much more important that the English written by Japanese authors be clear and easily readable than that it be elegant. Therefore, in a situation where there is a choice between an elegant form of expression which, however, may easily lead to confusion if misused and a less elegant but practically "foolproof" one, I have never hesitated to recommend the latter. Secondly, the importance of avoiding a mistake is roughly proportional to the amount of misunderstanding it may entail and/or the amount of psychological "wear and tear" it may cause on the reader's nerves. Accordingly, I have spent a good deal of space on "macroscopic" points like sentence construction, and proportionately less on "microscopic" ones like the correct use of "a" and "the"; prepositions, which most Japanese writers seem to consider a major point of difficulty in writing English, I have scarcely mentioned, not only because this is the sort of point for which one can easily refer to dictionaries but because I believe the reader can usually correct any mistakes for himself with very little mental effort. Thirdly, the usefulness of a set of notes such as this is much reduced if the rules given become too complicated. Therefore, rather than give a complicated set of rules which would ensure correctness 100% of the time, I have often preferred to give a simple rule which will be right 95% of the time, provided that in the other 5% of cases, it is unlikely to lead to confusion. I do not claim that anyone who tries to follow the advice given here will write beautiful or even invariably correct English; but I hope that what he writes will be clear and readable and that any mistakes he does make will be minor ones.
Algebra-coalgebra duality in brzozowski's minimization algorithm
Authors: Bonchi Filippo , Bonsangue Marcello M. , Hansen Helle H. , Panangaden Prakash , Rutten Jan J. M. M. , Silva Alexandra
Published: March 2014

We give a new presentation of Brzozowski's algorithm to minimize finite automata using elementary facts from universal algebra and coalgebra and building on earlier work by Arbib and Manes on a categorical presentation of Kalman duality between reachability and observability. This leads to a simple proof of its correctness and opens the door to further generalizations. Notably, we derive algorithms to obtain minimal language equivalent automata from Moore nondeterministic and weighted automata.
A separability framework for analyzing community structure
Authors: Abrahao Bruno , Soundarajan Sucheta , Hopcroft John , Kleinberg Robert
Published: March 2014

Four major factors govern the intricacies of community extraction in networks: (1) the literature offers a multitude of disparate community detection algorithms whose output exhibits high structural variability across the collection, (2) communities identified by algorithms may differ structurally from real communities that arise in practice, (3) there is no consensus characterizing how to discriminate communities from noncommunities, and (4) the application domain includes a wide variety of networks of fundamentally different natures. In this article, we present a class separability framework to tackle these challenges through a comprehensive analysis of community properties. Our approach enables the assessment of the structural dissimilarity among the output of multiple community detection algorithms and between the output of algorithms and communities that arise in practice. In addition, our method provides us with a way to organize the vast collection of community detection algorithms by grouping those that behave similarly. Finally, we identify the most discriminative graph-theoretical properties of community signature and the small subset of properties that account for most of the biases of the different community detection algorithms. We illustrate our approach with an experimental analysis, which reveals nuances of the structure of real and extracted communities. In our experiments, we furnish our framework with the output of 10 different community detection procedures, representative of categories of popular algorithms available in the literature, applied to a diverse collection of large-scale real network datasets whose domains span biology, online shopping, and social systems. We also analyze communities identified by annotations that accompany the data, which reflect exemplar communities in various domain. We characterize these communities using a broad spectrum of community properties to produce the different structural classes. As our experiments show that community structure is not a universal concept, our framework enables an informed choice of the most suitable community detection method for identifying communities of a specific type in a given network and allows for a comparison of existing community detection algorithms while guiding the design of new ones.
Disambiguation of imprecise input with one-dimensional rotational text entry
Authors: Walmsley William S. , Snelgrove W. Xavier , Truong Khai N.
Published: March 2014

We introduce a distinction between disambiguation supporting continuous versus discrete ambiguous text entry. With continuous ambiguous text entry methods, letter selections are treated as ambiguous due to expected imprecision rather than due to discretized letter groupings. We investigate the simple case of a one-dimensional character layout to demonstrate the potential of techniques designed for imprecise entry. Our rotation-based sight-free technique, Rotext, maps device orientation to a layout optimized for disambiguation, motor efficiency, and learnability. We also present an audio feedback system for efficient selection of disambiguated word candidates and explore the role that time spent acknowledging word-level feedback plays in text entry performance. Through a user study, we show that despite missing on average by 2.46--2.92 character positions, with the aid of a
maximum a posteriori
(MAP) disambiguation algorithm, users can average a sight-free entry speed of 12.6wpm with 98.9% accuracy within 13 sessions (4.3 hours). In a second study, expert users are found to reach 21wpm with 99.6% accuracy after session 20 (6.7 hours) and continue to grow in performance, with individual phrases entered at up to 37wpm. A final study revisits the learnability of the optimized layout. Our modeling of ultimate performance indicates maximum overall sight-free entry speeds of 29.0wpm with audio feedback, or 40.7wpm if an expert user could operate without relying on audio feedback.
On the complexity of existential positive queries
Authors: Chen Hubie
Published: March 2014

We systematically investigate the complexity of model checking the existential positive fragment of first-order logic. In particular, for a set of existential positive sentences, we consider model checking where the sentence is restricted to fall into the set; a natural question is then to classify which sentence sets are tractable and which are intractable. With respect to fixed-parameter tractability, we give a general theorem that reduces this classification question to the corresponding question for primitive positive logic, for a variety of representations of structures. This general theorem allows us to deduce that an existential positive sentence set having bounded arity is fixed-parameter tractable if and only if each sentence is equivalent to one in bounded-variable logic. We then use the lens of classical complexity to study these fixed-parameter tractable sentence sets. We show that such a set can be NP-complete, and consider the length needed by a translation from sentences in such a set to bounded-variable logic; we prove superpolynomial lower bounds on this length using the theory of compilability, obtaining an interesting type of formula size lower bound. Overall, the tools, concepts, and results of this article set the stage for the future consideration of the complexity of model checking on more expressive logics.
A thermal-driven test application scheme for pre-bond and post-bond scan testing of three-dimensional ICs
Authors: Xiang Dong , Shen Kele
Published: March 2014

The three-dimensional (3-D) technology offers a new solution to the increasing density of integrated circuits (ICs). In this work, we propose novel scan architectures for 3-D IC pre-bond and post-bond testing by considering the interconnection overhead of through-silicon-vias (TSVs). Since hotspots in 3-D ICs often cause performance and reliability issues, we also develop different test ordering schemes for prebond and postbond testing to avoid applying test vectors that could worsen the temperature distribution. Experimental results show that the peak temperature can be lowered by 20% with the 3-D scan tree architecture. When combined with the test ordering scheme, the 3-D scan tree can further reduce peak temperature by over 30%.
RMDDS
Authors: Lin Chia-Chun , Jha Niraj K.
Published: March 2014

In this article, we propose a flexible and efficient reversible logic synthesizer. It exploits the complementary advantages of two methods: Reed-Muller Reversible Logic Synthesis (RMRLS) and Decision Diagram Synthesis (DDS), and is thus called Reed-Muller Decision Diagram Synthesis (RMDDS). RMRLS does not scale to a large number of qubits (i.e., quantum bits). DDS tools, even though efficient, add a large number of ancillary qubits and typically incur much higher quantum cost than necessary. RMDDS overcomes these obstacles. It is flexible in the sense that users can either optimize the number of qubits or the quantum cost in the circuit implementation. It is also efficient because the circuits can be synthesized within user-defined CPU times. This combination of flexibility and efficiency has been missing from synthesizers presented earlier. When used to synthesize reversible functions, RMDDS reduces the number of qubits by up to 79.2% (average of 54.6%) when the synthesis objective is to minimize the number of qubits and the quantum cost by up to 71.5% (average of 35.7%) when the synthesis objective is to minimize quantum cost, relative to DDS methods. For irreversible functions (which are automatically embedded in reversible functions), the corresponding best (average) reductions in the number of qubits is 42.1% (22.5%) when minimizing the number of qubits, and in quantum cost, it is 63.0% (25.9%) when minimizing quantum cost.
Delay-based processing-in-wire for design of QCA serial decimal arithmetic units
Authors: Gladshtein Michael
Published: March 2014

Quantum-dot cellular automata (QCA) technology is now considered to be one of the prospective technologies for a nanocomputer creation. The physical properties of QCA and its expanding range of computer applications make it expedient to use the novel paradigm of nanocomputer architecture: serial decimal storage-transfer-processing. The delay-based encoding of decimal digits allows the use a delay element as a main element of QCA serial arithmetic units. The simple implementation of the delay element by a short length of QCA wire results in reduction of complexity and of the area required for a QCA circuit. The theoretical basics of delay-based processing-in-wire and design examples of QCA serial decimal arithmetic units are presented.
Collaboratively designing assistive technology
Authors: Kane Shaun K. , Hurst Amy , Buehler Erin , Carrington Patrick A. , Williams Michele A.
Published: March 2014

In this forum we celebrate research that helps to successfully bring the benefits of computing technologies to children, older adults, people with disabilities, and other populations that are often ignored in the design of mass-marketed products. --
Juan Pablo Hourcade, Editor
Beyond video games for social change
Authors: Horn Michael S.
Published: March 2014

The boundaries between 'the digital' and our everyday physical world are dissolving as we develop more physical ways of interacting with computing. This forum presents some of the topics discussed in the colorful multidisciplinary field of tangible and embodied interaction. ---
Eva Hornecker, Editor
Reframing design culture and aging
Authors: Subasi Özge , Malmborg Lone , Fitzpatrick Geraldine , Östlund Britt
Published: March 2014

Community + Culture features practitioner perspectives on designing technologies for and with communities. We highlight compelling projects and provocative points of view that speak to both community technology practice and the interaction design field as a whole. ---
Christopher A. Le Dantec, Editor
Teaching design for development in computer science
Authors: Blake Edwin , Glaser Meryl , Freudenthal Adinda
Published: March 2014

When undertaking a project in community-based co-design, students and their teachers must embrace uncertainty.