bluuebunny/crossref_metadata_2025 huggingface dataset:
The setting up and running of a cross-county out-of-hours gastrointestinal bleed service: a possible blueprint for the future
Authors: Shokouhi Bahman N , Khan Mohammad , Carter Martyn J , Khan Nasser Q , Mills Philip , Morris Danielle , Rowlands David E , Samsheer Kote , Sargeant Ian R , McIntyre Peter B , Greenfield Simon M
Published: November 2012

Objective

Acute upper gastrointestinal bleeding (AUGIB) results in 25 000 hospital admissions annually. Patients admitted at weekends with AUGIB have increased mortality, and guidelines advise out-of-hours endoscopy. We present retrospective data from our service involving the interhospital transfer of patients.

Design

We pooled resources of two neighbouring general hospitals, just north of London. Emergency endoscopy is performed at the start of the list followed by elective endoscopy in the endoscopy unit on Saturday and Sunday mornings. From Friday evening to Sunday morning, patients admitted to Queen Elizabeth II Hospital (QEII) are medically stabilised and transferred to Lister Hospital by ambulance.

Results

240 endoscopies were performed out of hours from December 2007 to March 2011. Of these, 54 patients were transferred: nine had emergency endoscopy at QEII as they were medically unstable; eight of the patients transferred required therapeutic intervention for active bleeding. The mean pre-endoscopy Rockall score of those transferred was 2.5. We examined the records of 51 of the 54 patients transferred. There were three deaths within 30 days after endoscopy not associated with the transfer process. 19 (37%) patients had reduced hospitalisation after having their endoscopy at the weekend.

Conclusions

The introduction of the out-of-hours endoscopy service in our trust has had multiple benefits, including patients consistently receiving timely emergency endoscopy, significantly reduced disruption to emergency operating theatres, and participation of endoscopy nurses ensures a better and safer experience for patients, and better endoscopy decontamination. We suggest our model is safe and feasible for other small units wishing to set up their own out-of-hours endoscopy service to adopt.
Dependence of the clustering properties of galaxies on star formation rate and specific star formation rate
Authors: Deng Xin-Fa
Published: November 2012

The primary goal of this study is to explore the dependence of the clustering properties of galaxies on star formation rate (SFR) and specific star formation rate (SSFR). From the main galaxy sample of the Sloan Digital Sky Survey Data Release 7, we construct two volume-limited samples with absolute magnitudes above and below [Formula: see text], and then divide each volume-limited main galaxy sample into two subsamples with low SFRs and high SFRs or low SSFRs and high SSFRs. A strong dependence of the clustering properties on SFR and SSFR is found: high SFR and SSFR galaxies are preferentially isolated or found in close pairs and small groups, whereas low SFR and SSFR galaxies preferentially inhabit dense groups and clusters.
Sublinear optimization for machine learning
Authors: Clarkson Kenneth L. , Hazan Elad , Woodruff David P.
Published: November 2012

In this article we describe and analyze sublinear-time approximation algorithms for some optimization problems arising in machine learning, such as training linear classifiers and finding minimum enclosing balls. Our algorithms can be extended to some kernelized versions of these problems, such as SVDD, hard margin SVM, andL2-SVM, for which sublinear-time algorithms were not known before. These new algorithms use a combination of a novel sampling techniques and a new multiplicative update algorithm. We give lower bounds which show the running times of many of our algorithms to be nearly best possible in the unit-cost RAM model.
A quantum Lovász local lemma
Authors: Ambainis Andris , Kempe Julia , Sattath Or
Published: November 2012

The Lovász Local Lemma (LLL) is a powerful tool in probability theory to show the existence of combinatorial objects meeting a prescribed collection of “weakly dependent” criteria. We show that the LLL extends to a much more general geometric setting, where events are replaced with subspaces and probability is replaced with relative dimension, which allows to lower bound the dimension of the intersection of vector spaces under certain independence conditions.

Our result immediately applies to the
k
-
qsat
problem (quantum analog of
k
-
sat
): For instance we show that any collection of rank-1 projectors, with the property that each qubit appears in at most 2

k

/(
e
ċ
k
) of them, has a joint satisfiable state.

We then apply our results to the recently studied model of random
k
-
qsat
. Recent works have shown that the satisfiable region extends up to a density of 1 in the large
k
limit, where the density is the ratio of projectors to qubits. Using a hybrid approach building on work by Laumann et al. [2009, 2010] we greatly extend the known satisfiable region for random
k
-
qsat
to a density of Ω(2

k

/
k
2
). Since our tool allows us to show the existence of joint satisfying states without the need to construct them, we are able to penetrate into regions where the satisfying states are conjectured to be entangled, avoiding the need to construct them, which has limited previous approaches to product states.
Fixed-point definability and polynomial time on graphs with excluded minors
Authors: Grohe Martin
Published: November 2012

We give a logical characterization of the polynomial-time properties of graphs embeddable in some surface. For every surfaceS, a property P of graphs embeddable inSis decidable in polynomial time if and only if it is definable in fixed-point logic with counting. It is a consequence of this result that for every surfaceSthere is aksuch that a simple combinatorial algorithm, namely “thek-dimensional Weisfeiler-Lehman algorithm”, decides isomorphism of graphs embeddable inSin polynomial time.

We also present (without proof) generalizations of these results to arbitrary classes of graphs with excluded minors.
Demo hour
Authors: Hoinkis Monika , Ibars Roger , Nakamura Hiromi , Miyashita Homei , Heimerl Kurtis , Gawalt Brian , Chen Kuang , Parikh Tapan , Hartmann Björn
Published: November 2012

Demo Hour highlights new prototypes and projects that exemplify innovation and novel forms of interaction.

Leah Maestri, Editor
The CRISPRs, They Are A-Changin': How Prokaryotes Generate Adaptive Immunity
Authors: Westra Edze R. , Swarts Daan C. , Staals Raymond H.J. , Jore Matthijs M. , Brouns Stan J.J. , van der Oost John
Published: November 2012

All organisms need to continuously adapt to changes in their environment. Through horizontal gene transfer, bacteria and archaea can rapidly acquire new traits that may contribute to their survival. However, because new DNA may also cause damage, removal of imported DNA and protection against selfish invading DNA elements are also important. Hence, there should be a delicate balance between DNA uptake and DNA degradation. Here, we describe prokaryotic antiviral defense systems, such as receptor masking or mutagenesis, blocking of phage DNA injection, restriction/modification, and abortive infection. The main focus of this review is on CRISPR (clustered regularly interspaced short palindromic repeats)/Cas (CRISPR-associated), a prokaryotic adaptive immune system. Since its recent discovery, our biochemical understanding of this defense system has made a major leap forward. Three highly diverse CRISPR/Cas types exist that display major structural and functional differences in their mode of generating resistance against invading nucleic acids. Because several excellent recent reviews cover all CRISPR subtypes, we mainly focus on a detailed description of the type I-E CRISPR/Cas system of the model bacterium Escherichia coli K12.
Active Transposition in Genomes
Authors: Huang Cheng Ran Lisa , Burns Kathleen H. , Boeke Jef D.
Published: November 2012

Transposons are DNA sequences capable of moving in genomes. Early evidence showed their accumulation in many species and suggested their continued activity in at least isolated organisms. In the past decade, with the development of various genomic technologies, it has become abundantly clear that ongoing activity is the rule rather than the exception. Active transposons of various classes are observed throughout plants and animals, including humans. They continue to create new insertions, have an enormous variety of structural and functional impact on genes and genomes, and play important roles in genome evolution. Transposon activities have been identified and measured by employing various strategies. Here, we summarize evidence of current transposon activity in various plant and animal genomes.
Variational Methods for NLEV Approximation Near a Bifurcation Point
Authors: Chiappinelli Raffaele
Published: November 2012

We review some more and less recent results concerning bounds on nonlinear eigenvalues (NLEV) for gradient operators. In particular, we discuss the asymptotic behaviour of NLEV (as the norm of the eigenvector tends to zero) in bifurcation problems from the line of trivial solutions, considering perturbations of linear self-adjoint operators in a Hilbert space. The proofs are based on the Lusternik-Schnirelmann theory of critical points on one side and on the Lyapounov-Schmidt reduction to the relevant finite-dimensional kernel on the other side. The results are applied to some semilinear elliptic operators in bounded domains ofℝN. A section reviewing some general facts about eigenvalues of linear and nonlinear operators is included.
Convergence and Stability in Collocation Methods of Equation u′(t) = au(t) + bu([t])
Authors: Yan Han , Ma Shufang , Liu Yanbin , Sun Hongquan
Published: November 2012

This paper is concerned with the convergence, global superconvergence, local superconvergence, and stability of collocation methods for u′(t) = au(t) + bu([t]). The optimal convergence order and superconvergence order are obtained, and the stability regions for the collocation methods are determined. The conditions that the analytic stability region is contained in the numerical stability region are obtained, and some numerical experiments are given.
Development of Robots with Soft Sensor Flesh for Achieving Close Interaction Behavior
Authors: Yoshikai Tomoaki , Hayashi Marika , Ishizaka Yui , Fukushima Hiroko , Kadowaki Asuka , Sagisaka Takashi , Kobayashi Kazuya , Kumagai Iori , Inaba Masayuki
Published: November 2012

In order to achieve robots' working around humans, safe contacts against objects, humans, and environments with broad area of their body should be allowed. Furthermore, it is desirable to actively use those contacts for achieving tasks. Considering that, many practical applications will be realized by whole-body close interaction of many contacts with others. Therefore, robots are strongly expected to achieve whole-body interaction behavior with objects around them. Recently, it becomes possible to construct whole-body tactile sensor network by the advancement of research for tactile sensing system. Using such tactile sensors, some research groups have developed robots with whole-body tactile sensing exterior. However, their basic strategy is making a distributed 1-axis tactile sensor network covered with soft thin material. Those are not sufficient for achieving close interaction and detecting complicated contact changes. Therefore, we propose “Soft Sensor Flesh.” Basic idea of “Soft Sensor Flesh” is constructing robots' exterior with soft and thick foam with many sensor elements including multiaxis tactile sensors. In this paper, a constructing method for the robot systems with such soft sensor flesh is argued. Also, we develop some prototypes of soft sensor flesh and verify the feasibility of the proposed idea by actual behavior experiments.
Salvianolic Acid B Attenuates Rat Hepatic Fibrosis via Downregulating Angiotensin II Signaling
Authors: Li Shu , Wang Lina , Yan Xiuchuan , Wang Qinglan , Tao Yanyan , Li Junxia , Peng Yuan , Liu Ping , Liu Chenghai
Published: November 2012

The renin-angiotensin system (RAS) plays an important role in hepatic fibrosis. Salvianolic acid B (Sal B), one of the water-soluble components from Radix Salviae miltiorrhizae, has been used to treat hepatic fibrosis, but it is still not clear whether the effect of Sal B is related to angiotensin II (Ang II) signaling pathway. In the present study, we studied Sal B effect on rat liver fibrosis and Ang-II related signaling mediators in dimethylnitrosamine-(DMN-) induced rat fibrotic modelin vivoand Ang-II stimulated hepatic stellate cells (HSCs)in vitro, with perindopril or losartan as control drug, respectively. The results showed that Sal B and perindopril inhibited rat hepatic fibrosis and reduced expression of Ang II receptor type 1 (AT1R) and ERK activation in fibrotic liver. Sal B and losartan also inhibited Ang II-stimulated HSC activation including cell proliferation and expression of type I collagen I (Col-I) andα-smooth muscle actin (α-SMA) productionin vitro, reduced the gene expression of transforming growth factor beta (TGF-β), and downregulated AT1R expression and ERK and c-Jun phosphorylation. In conclusion, our results indicate that Sal B may exert an antihepatic fibrosis effect via downregulating Ang II signaling in HSC activation.
An Attempt at Quantifying Factors that Affect Efficiency in the Management of Solid Waste Produced by Commercial Businesses in the City of Tshwane, South Africa
Authors: Worku Yohannes , Muchie Mammo
Published: November 2012

Objective. The objective was to investigate factors that affect the efficient management of solid waste produced by commercial businesses operating in the city of Pretoria, South Africa.Methods. Data was gathered from 1,034 businesses. Efficiency in solid waste management was assessed by using a structural time-based model designed for evaluating efficiency as a function of the length of time required to manage waste. Data analysis was performed using statistical procedures such as frequency tables, Pearson’s chi-square tests of association, and binary logistic regression analysis. Odds ratios estimated from logistic regression analysis were used for identifying key factors that affect efficiency in the proper disposal of waste.Results. The study showed that 857 of the 1,034 businesses selected for the study (83%) were found to be efficient enough with regards to the proper collection and disposal of solid waste. Based on odds ratios estimated from binary logistic regression analysis, efficiency in the proper management of solid waste was significantly influenced by 4 predictor variables. These 4 influential predictor variables are lack of adherence to waste management regulations, wrong perception, failure to provide customers with enough trash cans, and operation of businesses by employed managers, in a decreasing order of importance.
Solving Singular Two‐Point Boundary Value Problems Using Continuous Genetic Algorithm
Authors: Abu Arqub Omar , Abo-Hammour Zaer , Momani Shaher , Shawagfeh Nabil
Published: November 2012

In this paper, the continuous genetic algorithm is applied for the solution of singular two‐point boundary value problems, where smooth solution curves are used throughout the evolution of the algorithm to obtain the required nodal values. The proposed technique might be considered as a variation of the finite difference method in the sense that each of the derivatives is replaced by an appropriate difference quotient approximation. This novel approach possesses main advantages; it can be applied without any limitation on the nature of the problem, the type of singularity, and the number of mesh points. Numerical examples are included to demonstrate the accuracy, applicability, and generality of the presented technique. The results reveal that the algorithm is very effective, straightforward, and simple.
Lag Synchronization of Hyperchaotic Systems via Intermittent Control
Authors: Huang Junjian , Li Chuandong , Zhang Wei , Wei Pengcheng , Han Qi
Published: November 2012

Different from the most existing results, in this paper an intermittent control scheme is designed to achieve lag synchronization of coupled hyperchaotic systems. Several sufficient conditions ensuring lag synchronization are proposed by rigorous theoretical analysis with the help of the Lyapunov stability theory. Numerical simulations are also presented to show the effectiveness and feasibility of the theoretical results.
Computational Fluid Dynamic Analysis of a Vibrating Turbine Blade
Authors: Alshroof Osama N. , Forbes Gareth L. , Sawalhi Nader , Randall Robert B. , Yeoh Guan H.
Published: November 2012

This study presents the numerical fluid-structure interaction (FSI) modelling of a vibrating turbine blade using the commercial software ANSYS-12.1. The study has two major aims: (i) discussion of the current state of the art of modelling FSI in gas turbine engines and (ii) development of a “tuned” one-way FSI model of a vibrating turbine blade to investigate the correlation between the pressure at the turbine casing surface and the vibrating blade motion. Firstly, the feasibility of the complete FSI coupled two-way, three-dimensional modelling of a turbine blade undergoing vibration using current commercial software is discussed. Various modelling simplifications, which reduce the full coupling between the fluid and structural domains, are then presented. The one-way FSI model of the vibrating turbine blade is introduced, which has the computational efficiency of a moving boundary CFD model. This one-way FSI model includes the corrected motion of the vibrating turbine blade under given engine flow conditions. This one-way FSI model is used to interrogate the pressure around a vibrating gas turbine blade. The results obtained show that the pressure distribution at the casing surface does not differ significantly, in its general form, from the pressure at the vibrating rotor blade tip.
Urea‐Based Combustion Process for the Synthesis of Nanocrystalline Ni‐La‐Fe‐O Catalysts
Authors: Abu-Zied Bahaa , Asiri Abdullah M.
Published: November 2012

Nanocrystalline Ni‐La‐Fe‐O catalysts having the general formula NiLaxFe2−xO4 (0.00 ≤ x ≤ 2.00) were synthesized by the combustion route employing urea as a combustion fuel. The calcination process was affected at 500°C. The structural properties of the obtained catalysts were systematically investigated by X‐ray powder diffraction (XRD), scanning electronic microscopy (SEM), energy‐dispersive X‐ray spectra (EDX), and nitrogen adsorption at −196°C. Crystalline NiFe2O4 and La2NiO4 phases were detected for the catalysts having x = 0.00 and 2.00, respectively, as a result of solid‐solid interaction between mixtures precursors. The activity of the obtained catalysts was checked for hydrogen peroxide decomposition at 35–55°C. A synergic effect was observed for the catalysts having x‐value of 1.00 and 1.50. Such effect was attributed to the increase in the number of the active constituents involved in the catalytic decomposition of H2O2.
Train Stop Scheduling in a High‐Speed Rail Network by Utilizing a Two‐Stage Approach
Authors: Fu Huiling , Nie Lei , Sperry Benjamin R. , He Zhenhuan
Published: November 2012

Among the most commonly used methods of scheduling train stops are practical experience and various “one‐step” optimal models. These methods face problems of direct transferability and computational complexity when considering a large‐scale high‐speed rail (HSR) network such as the one in China. This paper introduces a two‐stage approach for train stop scheduling with a goal of efficiently organizing passenger traffic into a rational train stop pattern combination while retaining features of regularity, connectivity, and rapidity (RCR). Based on a three‐level station classification definition, a mixed integer programming model and a train operating tactics descriptive model along with the computing algorithm are developed and presented for the two stages. A real‐world numerical example is presented using the Chinese HSR network as the setting. The performance of the train stop schedule and the applicability of the proposed approach are evaluated from the perspective of maintaining RCR.
Getting Started with Taiji: Investigating Students Expectations and Teachers Appraisals of Taiji Beginners Courses
Authors: Nedeljkovic Marko , Bürgler Christina , Wirtz Petra H. , Seiler Roland , Streitberger Konrad M. , Ausfeld-Hafter Brigitte
Published: November 2012

In recent years, Taiji has been frequently investigated and considered as a stress management intervention. Although health care providers’ appraisals and consumers’ expectations are regarded as essential for treatment outcome, little attention has been drawn to this issue in Taiji research. In our study we have conducted two surveys to explore beginners’ (n=74) expectations and teachers’ (n=136) appraisals of their Taiji courses in general as well as more particularly related to stress management. Qualitative data analysis revealed that beginners mainly expected to learn a new method that is applicable in their daily life to foster peace of mind and to enhance their stress management. Congruently moderate-to-high improvements in stress management have also been found in quantitative analysis, whereby a lower educational level predicted higher expectations (P=0.016). Taiji-teachers stated body- and mind-related benefits most frequently and appraised moderate-to-high improvements in stress management. Higher appraisals were predicted by a shorter teaching experience (P=0.024). Our results inform about beginners’ expectations and teachers’ appraisals related to a Taiji-beginners course and highlight the role of educational background and teaching experience in shaping stress-management-related beginners’ expectations and teachers’ appraisals.
Attenuation of TRPV1 and TRPV4 Expression and Function in Mouse Inflammatory Pain Models Using Electroacupuncture
Authors: Chen Wei-Hsin , Tzen Jason T. C. , Hsieh Ching Liang , Chen Yung Hsiang , Lin Tzu-Jou , Chen Shih-Yin , Lin Yi-Wen
Published: November 2012

Although pain is a major human affliction, our understanding of pain mechanisms is limited. TRPV1 (transient receptor potential vanilloid subtype 1) and TRPV4 are two crucial receptors involved in inflammatory pain, but their roles in EA- (electroacupuncture-) mediated analgesia are unknown. We injected mice with carrageenan (carra) or a complete Freund’s adjuvant (CFA) to model inflammatory pain and investigated the analgesic effect of EA using animal behavior tests, immunostaining, Western blotting, and a whole-cell recording technique. The inflammatory pain model mice developed both mechanical and thermal hyperalgesia. Notably, EA at the ST36 acupoint reversed these phenomena, indicating its curative effect in inflammatory pain. The protein levels of TRPV1 and TRPV4 in DRG (dorsal root ganglion) neurons were both increased at day 4 after the initiation of inflammatory pain and were attenuated by EA, as demonstrated by immunostaining and Western blot analysis. We verified DRG electrophysiological properties to confirm that EA ameliorated peripheral nerve hyperexcitation. Our results indicated that the AP (action potential) threshold, rise time, and fall time, and the percentage and amplitude of TRPV1 and TRPV4 were altered by EA, indicating that EA has an antinociceptive role in inflammatory pain. Our results demonstrate a novel role for EA in regulating TRPV1 and TRPV4 protein expression and nerve excitation in mouse inflammatory pain models.
Schwarz‐Pick Estimates for Holomorphic Mappings with Values in Homogeneous Ball
Authors: Wang Jianfei
Published: November 2012

Let BX be the unit ball in a complex Banach space X. Assume BX is homogeneous. The generalization of the Schwarz‐Pick estimates of partial derivatives of arbitrary order is established for holomorphic mappings from the unit ball Bn to BX associated with the Carathéodory metric, which extend the corresponding Chen and Liu, Dai et al. results.
Multiple Linear Regression Model Based on Neural Network and Its Application in the MBR Simulation
Authors: Li Chunqing , Yang Zixiang , Deng Yiquan , Wang Tao
Published: November 2012

The computer simulation of the membrane bioreactor MBR has become the research focus of the MBR simulation. In order to compensate for the defects, for example, long test period, high cost, invisible equipment seal, and so forth, on the basis of conducting in‐depth study of the mathematical model of the MBR, combining with neural network theory, this paper proposed a three‐dimensional simulation system for MBR wastewater treatment, with fast speed, high efficiency, and good visualization. The system is researched and developed with the hybrid programming of VC++ programming language and OpenGL, with a multifactor linear regression model of affecting MBR membrane fluxes based on neural network, applying modeling method of integer instead of float and quad tree recursion. The experiments show that the three‐dimensional simulation system, using the above models and methods, has the inspiration and reference for the future research and application of the MBR simulation technology.
An Extended Analytic Solution of Combined Refraction andDiffraction of Long Waves Propagating over Circular Island
Authors: Kuo Yu-Shu , Hsu Tai-Wen , Tsai Chia-Cheng , Huang Yu-Hsuan
Published: November 2012

An analytic solution of long waves scattering by a cylindrical island mounted on a permeable circular shoal was obtained by solving the linear long wave equation (LWE). The solution is in terms of the Bessel function expressed by complex variables. The present solution is suitable for arbitrary bottom configurations described by a power function with two independent parameters. For the case of the paraboloidal shoal, there exists a singular point (α = 2) which can be removed using Frobenius series, where α is a real constant. The present solution is reduced to Yu and Zhang’s (2003) solution for impermeable circular shoal. The numerical results show some special features of the combined effect of wave refraction and diffraction caused by a porous circular island. The effect of key parameters of the island dimension, the shoal slope, and permeability on wave scattering was discussed based on the analytic solution.
An Integrated Multicriterion hp‐Adaptive Pseudospectral Method for Direct Optimal Control Problems Solving
Authors: Liu Hongfu , Chen Shaofei , Shen Lincheng , Chen Jing
Published: November 2012

Pseudospectral methods (PMs) for solving general optimal control problems (OCPs) attract an increasing amount of research and application in engineering. It is challenging to improve the convergence rate, the solution accuracy, and the applicability of PMs, especially for nonsmooth problems. Existing hp‐adaptive PMs consider only one heuristic criterion, which cannot produce satisfactory performance in many cases. In this paper, we propose a novel method which integrates multicriterion to hp‐adaptive PM, in order to further improve the performance. For this purpose, we first devise an OCP solving framework of hp‐adaptive PM. We then design a multicriterion hp‐adaptive strategy which introduces prior knowledge, intermediate error and curvature as useful criterions for adaptive refinement. We last present an iterative procedure for solving general nonlinear OCPs. Results from two examples show that our method significantly outperforms competitors on the convergence rate and the solution accuracy. The method is practical and effective for direct solving of various OCPs in a broad range of engineering.
Simulation of Land-Use Development, Using a Risk-Regarding Agent-Based Model
Authors: Hosseinali F. , Alesheikh A. A. , Nourian F.
Published: November 2012

The aim of this paper is to study the spatial consequences of applying different Attitude Utility Functions (AUFs), which reflect peoples’ simplified psychological frames, to investment plans in land-use decision making. For this purpose, we considered and implemented an agent-based model with new methods for searching landscapes, for selecting parcels to develop, and for allowing competitions among agents. Besides this, GIS (Geographic Information Systems) as a versatile and powerful medium of analyzing and representing spatial data is used. Our model is implemented on an artificial landscape in which land is being developed by agents. The agents are assumed to be mobile developers that are equipped with several land-related objectives. In this paper, agents mimic various risk-bearing attitudes and sometimes compete for developing the same parcel. The results reveal that patterns of land-use development are different in the two cases of regarding and disregarding AUFs. Therefore, it is considered here that using the attitudes of people towards risk helps the model to better simulate the decision making of land-use developers. The different attitudes toward risk used in this study can be attributed to different categories of developers based on sets of characteristics such as income, age, or education.
Paraoxonase and Arylesterase Activities, Lipid Profile, and Oxidative Damage in Experimental Ischemic Colitis Model
Authors: Unal Ethem , Eris Cengiz , Kaya Bülent , Uzun Hafize , Cavdar Faruk , Yildar Murat , Kiziler Ali Riza , Aydemir Birsen , Gunes Pembegul , Kutanis Riza , Titiz Izzet
Published: November 2012

Objective. In the present study, since PON1 is known as an HDL-associated antioxidant enzyme that inhibits the oxidative modification of LDL and oxidative stress plays a role in the pathogenesis of mesenteric ischemia, we investigated the changes in PON1 activity and lipid profile in an experimental ischemic colitis model.Methods. Forty male Wistar albino rats were divided into two groups: the control group (N=15) and the experimental group (N=25). All animals were anesthetized with ether and ketamine anesthesia to undergo a midline laparotomy. Ischemic colitis was induced by marginal vessel ligation in the splenic flexura (devascularization process). A sham laparotomy was performed in the control group. All animals were sacrificed on the seventh postoperative day. Oxidative stress marker (malonyldialdehyde, MDA), lipid profile, and paraoxonase (PON-1) and arylesterase activities were determined. Histopathological evaluation was done under light microscopy, after sectioning and staining with hematoxyline and eosin. Statistical analysis was conducted using Student’st-test and Mann-WhitneyUtest, andP<0.05was considered as statistically significant.Results. There was a significant decrease in both serum and tissue PON1 activity in ischemic colitis group (P<0.01, for each). Similarly, arylesterase levels showed a parallel decrease in both tissue and serum of the experimental group (P<0.01andP<0.001, retrospectively). MDA, an oxidative stress marker, was seen to increase in the experimental group (P<0.01, tissue;P<0.05, serum). In experimental group, there was a significant rise in serum total cholesterol and LDL levels (P<0.001, for each). However, HDL level decreased significantly (P<0.001). Triglycerides did not show any change between the groups (P>0.05).Conclusions. PON1 and arylesterase play an important role in the pathophysiology of ischemic colitis.
CdS Loaded an Iranian Clinoptilolite as a Heterogeneous Catalyst in Photodegradation of p‐Aminophenol
Authors: Nezamzadeh-Ejhieh Alireza , Shirvani Khodarahm
Published: November 2012

Natural clinoptilolite, zeolite  CdS‐incorporated  was prepared by ion exchange and precipitation procedures and it was characterized by FT‐IR, XRD, and thermal methods. The prepared composite was used as a catalyst in the photodegradation process of p‐aminophenol in aqueous solution under UV irradiation. The effect of some key operating parameters such as catalyst dosage, temperature, the initial concentration of the pollutant, and initial pH of the solutions on the degradation process of the pollutant was studied. The primary objective was to determine the optimal conditions for each of the parameters. UV‐vis spectrophotometric measurements were performed for the determination of degradation and mineralization extents. The optimal operation parameters were found as follows: pH 5, 17.5 mg·L−1 of catalyst loading, and 10 ppm of dye concentration. The CdS particles out of zeolite framework do not show significant degradation efficiency. The degradation process obeyed first‐order kinetics.
Potentiometric and Thermodynamic Studies of Some Schiff‐Base Derivatives of 4‐Aminoantipyrine and Their Metal Complexes
Authors: El-Bindary A. A. , El-Sonbati A. Z. , Diab M. A. , Abd El-Kader M. K.
Published: November 2012

The proton‐ligand dissociation constant of 4‐(4‐amino‐1,5‐dimethyl‐2‐phenyl‐1,2‐dihydro‐pyrazol‐3‐ylideneamino)‐phenol (L1) and 4‐(4‐amino‐1,5‐dimethyl‐2‐phenyl‐1,2‐dihydro‐pyrazol‐3‐ylideneamino)‐benzoic acid (L2) and metal‐ligand stability constants of their complexes with metal ions (Mn2+, Co2+, Ni2+, and Cu2+) have been determined potentiometrically in 0.1 mol·dm−3 KCl and 10% (by volume) ethanol‐water mixture and at 298, 308, and 318 K. The stability constants of the formed complexes increase in the order Mn2+, Co2+, Ni2+, and Cu2+. The effect of temperature was studied, and the corresponding thermodynamic parameters (ΔG, ΔH, and ΔS) were derived and discussed. The dissociation process is nonspontaneous, endothermic, and entropically unfavourable. The formation of the metal complexes has been found to be spontaneous, endothermic, and entropically favourable.
Biosorption Behavior of Basic Red 46 and Violet 3 by Dead Pleurotus mutilus from Single‐ and Multicomponent Systems
Authors: Yeddou Mezenner N. , Hamadi A. , Kaddour S. , Bensaadi Z. , Bensmaili A.
Published: November 2012

The performance of nonviable P. mutilus for removal of Crystal Violet (CV) and Basic Red 46 (BR46) was investigated in single and binary systems. Batch kinetic studies were carried out as a function of pH, temperature, biomass amount, and dye concentration to determine the decolorization efficiency of biosorbent. In single system, the biosorption capacities of P. M. reached 166 and 76.92 mg/g for CV and BR46, respectively. A comparison of kinetic models applied to the adsorption of basic dyes onto P. Mutilus was evaluated for the pseudo‐second‐order and intraparticle diffusion kinetics models. The experimental data fitted very well the pseudo‐second‐order kinetic model, whereas diffusion is not only the rate‐controlling step. The thermodynamic study indicates that the adsorption of dyes is spontaneous and endothermic process. In binary system, the biosorption capacities of P. Mutilus for both dyes decreased significantly compared to that in single system. Competitive coefficients calculated on a concentration basis using Sheindorf‐Rebhun‐Sheintuch (SRS) equation were useful for describing the degree of competitive interaction in P. M.
Age, Sex, and Hypertension-Related Remodeling Influences Left Ventricular Torsion Assessed by Tagged Cardiac Magnetic Resonance in Asymptomatic Individuals
Authors: Yoneyama Kihei , Gjesdal Ola , Choi Eui-Young , Wu Colin O. , Hundley W. Gregory , Gomes Antoinette S. , Liu Chia-Ying , McClelland Robyn L. , Bluemke David A. , Lima Joao A.C.
Published: November 2012

Background—

The aim of the present study was to evaluate how torsion is influenced by left ventricular (LV) remodeling associated with age, sex, and hypertension in a large community-based population.

Methods and Results—

Myocardial shortening and torsion were assessed by tagged cardiac magnetic resonance in 1478 participants without clinically apparent cardiovascular disease in the Multi-Ethnic Study of Atherosclerosis (MESA). Torsion was defined as the difference between apical and basal rotation divided by slice distance. In multivariable linear regression models, older age was associated with lower stroke volume (−3.6 mL per decade;
P
<0.001) and higher LV mass-to-volume ratio (0.03 g/mL per decade;
P
<0.001), along with lower circumferential shortening (−0.17% per decade;
P
<0.05). Torsion, however, was greater at older ages (0.14° per decade;
P
<0.001) and in women (0.37°/cm versus men;
P
<0.001). Hypertensive participants had higher LV mass and LV mass-to-volume ratio (15.5 g and 0.07 g/mL, respectively;
P
<0.001 for both). Circumferential shortening was lower in hypertensive (−0.42%;
P
<0.01), whereas torsion was higher after adjustment for age and sex (0.17°/cm;
P
<0.05).

Conclusions—

Older age is associated with lower LV volumes and greater relative wall thickness and is accompanied by lower circumferential myocardial shortening, whereas torsion is greater with older age. Hypertensive individuals have greater LV volumes and relative wall thickness and lower circumferential shortening. Torsion, however, is greater in hypertension independently of age and sex. Torsion may therefore represent a compensatory mechanism to maintain an adequate stroke volume and cardiac output in the face of the progressively reduced LV volumes and myocardial shortening associated with hypertension and aging.
Supervised Learning in Multilayer Spiking Neural Networks
Authors: Sporea Ioana , Grüning André
Published: November 2012

We introduce a supervised learning algorithm for multilayer spiking neural networks. The algorithm overcomes a limitation of existing learning algorithms: it can be applied to neurons firing multiple spikes in artificial neural networks with hidden layers. It can also, in principle, be used with any linearizable neuron model and allows different coding schemes of spike train patterns. The algorithm is applied successfully to classic linearly nonseparable benchmarks such as the XOR problem and the Iris data set, as well as to more complex classification and mapping problems. The algorithm has been successfully tested in the presence of noise, requires smaller networks than reservoir computing, and results in faster convergence than existing algorithms for similar tasks such as SpikeProp.
Accelerated Spike Resampling for Accurate Multiple Testing Controls
Authors: Harrison Matthew T.
Published: November 2012

Controlling for multiple hypothesis tests using standard spike resampling techniques often requires prohibitive amounts of computation. Importance sampling techniques can be used to accelerate the computation. The general theory is presented, along with specific examples for testing differences across conditions using permutation tests and for testing pairwise synchrony and precise lagged-correlation between many simultaneously recorded spike trains using interval jitter.
Temporal Order Detection and Coding in Nervous Systems
Authors: Stiefel Klaus M. , Tapson Jonathan , van Schaik André
Published: November 2012

This letter discusses temporal order coding and detection in nervous systems. Detection of temporal order in the external world is an adaptive function of nervous systems. In addition, coding based on the temporal order of signals can be used as an internal code. Such temporal order coding is a subset of temporal coding. We discuss two examples of processing the temporal order of external events: the auditory location detection system in birds and the visual direction detection system in flies. We then discuss how somatosensory stimulus intensities are translated into a temporal order code in the human peripheral nervous system. We next turn our attention to input order coding in the mammalian cortex. We review work demonstrating the capabilities of cortical neurons for detecting input order. We then discuss research refuting and demonstrating the representation of stimulus features in the cortex by means of input order. After some general theoretical considerations on input order detection and coding, we conclude by discussing the existing and potential use of input order coding in neuromorphic engineering.
Multidecadal to Centennial Variability of the AMOC: HadCM3 and a Perturbed Physics Ensemble
Authors: Jackson Laura , Vellinga Michael
Published: November 2012

Multidecadal to centennial variability of the Atlantic meridional overturning circulation (AMOC) is investigated in a multi-thousand-year simulation of the third version of the Hadley Centre Coupled Model (HadCM3) and in an ensemble of general circulation models (GCMs) based on HadCM3 with perturbed physics. Large changes in the AMOC in the standard HadCM3 are strongly related to salinity anomalies in the deep-water formation regions, with anomalies arriving via two pathways. The first is from a coupled feedback in the equatorial Atlantic Ocean, described previously by Vellinga and Wu, and the second is from variability in the Arctic Ocean, possibly driven by stochastic sea level pressure. The low-frequency variability of the AMOC in HadCM3 is well predicted from salinity anomalies from these two pathways. The sensitivity of these processes to model physics is investigated using a small ensemble based on HadCM3 where parameters relating to physical processes are varied. The AMOC responds consistently to the salinity anomalies in the ensemble members. However, 1) the timing of the response depends on the background climate state and 2) some ensemble members have significantly larger AMOC and salinity variability than in standard HadCM3 simulations. In this small ensemble, the presence and strength of multidecadal to centennial AMOC variability is associated with the variability of salinity exported from the Arctic, with little multidecadal to centennial variability of either in the coldest members. This demonstrates how the background climate state can alter the frequency and strength of AMOC variability and is a first step toward understanding how AMOC variability differs within a multimodel context.
The Role of Oceans and Sea Ice in Abrupt Transitions between Multiple Climate States
Authors: Rose Brian E. J. , Ferreira David , Marshall John
Published: November 2012

The coupled climate dynamics underlying large, rapid, and potentially irreversible changes in ice cover are studied. A global atmosphere–ocean–sea ice general circulation model with idealized aquaplanet geometry is forced by gradual multi-millennial variations in solar luminosity. The model traverses a hysteresis loop between warm ice-free conditions and cold glacial conditions in response to ±5 W m−2 variations in global, annual-mean insolation. Comparison of several model configurations confirms the importance of polar ocean processes in setting the sensitivity and time scales of the transitions. A “sawtooth” character is found with faster warming and slower cooling, reflecting the opposing effects of surface heating and cooling on upper-ocean buoyancy and, thus, effective heat capacity. The transition from a glacial to warm, equable climate occurs in about 200 years.

In contrast to the “freshwater hosing” scenario, transitions are driven by radiative forcing and sea ice feedbacks. The ocean circulation, and notably the meridional overturning circulation (MOC), does not drive the climate change. The MOC (and associated heat transport) collapses poleward of the advancing ice edge, but this is a purely passive response to cooling and ice expansion. The MOC does, however, play a key role in setting the time scales of the transition and contributes to the asymmetry between warming and cooling.
The Relationship between ITCZ Location and Cross-Equatorial Atmospheric Heat Transport: From the Seasonal Cycle to the Last Glacial Maximum
Authors: Donohoe Aaron , Marshall John , Ferreira David , Mcgee David
Published: November 2012

The authors quantify the relationship between the location of the intertropical convergence zone (ITCZ) and the atmospheric heat transport across the equator (AHTEQ) in climate models and in observations. The observed zonal mean ITCZ location varies from 5.3°S in the boreal winter to 7.2°N in the boreal summer with an annual mean position of 1.65°N while the AHTEQ varies from 2.1 PW northward in the boreal winter to 2.3 PW southward in the boreal summer with an annual mean of 0.1 PW southward. Seasonal variations in the ITCZ location and AHTEQ are highly anticorrelated in the observations and in a suite of state-of-the-art coupled climate models with regression coefficients of −2.7° and −2.4° PW−1 respectively. It is also found that seasonal variations in ITCZ location and AHTEQ are well correlated in a suite of slab ocean aquaplanet simulations with varying ocean mixed layer depths. However, the regression coefficient between ITCZ location and AHTEQ decreases with decreasing mixed layer depth as a consequence of the asymmetry that develops between the winter and summer Hadley cells as the ITCZ moves farther off the equator.

The authors go on to analyze the annual mean change in ITCZ location and AHTEQ in an ensemble of climate perturbation experiments including the response to CO2 doubling, simulations of the Last Glacial Maximum, and simulations of the mid-Holocene. The shift in the annual average ITCZ location is also strongly anticorrelated with the change in annual mean AHTEQ with a regression coefficient of −3.2° PW−1, similar to that found over the seasonal cycle.
Variational Estimation of Land–Atmosphere Heat Fluxes and Land Surface Parameters Using MODIS Remote Sensing Data
Authors: Meng Chunlei , Zhang Chaolin , Tang Ronglin
Published: November 2012

A variational data assimilation algorithm for assimilating the land surface temperature (LST) into the Common Land Model (CLM) was implemented using the land surface energy balance equation as the adjoint physical constraint. In this data assimilation algorithm, the evaporative fractions of the soil and canopy were adjusted according to the remotely sensed surface temperature observations. This paper developed a very simple analytical algorithm to characterize the errors’ weighting matrices in the cost function. The leaf area index (LAI) retrieved from the Moderate Resolution Imaging Spectroradiometer (MODIS) was also assimilated into CLM using the direct insertion method. The analysis results from the CLM with the LST assimilation algorithm compare well with MODIS and field observations for the Yucheng site, especially in daytime. On the basis of the histogram of the error of the LST, it can be concluded that after assimilation, the LST was greatly improved in comparison with the MODIS observations, especially in daytime. These results indicate that this surface temperature assimilation method is efficient and effective, even when only one time observational LST data point is available for each day, especially in daytime. The regional spatial patterns of evapotranspiration and soil surface moisture were also compared before assimilation on the basis of LAI data calculated using the empirical formula, before assimilation on the basis of MODIS LAI data, and after assimilation on the basis of MODIS LAI data.
Using a rate equations approach to model World population trends
Authors: Gonzalo Julio A , Muñoz Felix-Fernando , Santos David J
Published: November 2012

According to UN data and projections, the World population will begin to decrease by the middle of this century. This paper uses rate equations (fully analogous to those employed in condensed matter physics) to simulate the time evolution of World population, making use of UN population data in the time interval 1900–2010, and to extrapolate the evolution of World population into the near future. This approach has not been used in economics and population dynamics. The simulation predicts a population decline by mid-century. The economic consequences of a population decline would be far reaching.