bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of high temperatures on cause-specific mortality in England and Wales
Authors: Gasparrini Antonio , Armstrong Ben , Kovats Sari , Wilkinson Paul
Published: March 2011

Objectives

Several observational studies have suggested an association between high temperatures and all-cause mortality. However, estimates on more specific mortality outcomes are sparse, and frequently assessed in studies using different analytical methods.

Methods

A time series analysis was performed on 10 regions in England and Wales during the summers (June–September) of 1993–2006. Average percentage linear increases in risk for a 1°C increase in temperature above region-specific thresholds and attributable deaths were computed by cause-specific mortality and age groups (0–64, 65–74, 75–84, 85+).

Results

There was evidence of increased mortality with heat for almost all cause-of-death groups examined, with an overall increase in all-cause mortality of 2.1% (95% CI 1.6% to 2.6%) for a 1°C rise above the regional heat threshold. Among main causes, the steepest increase in risk was for respiratory mortality (+4.1% (3.5% to 4.8%) per 1°C). It was much smaller for cardiovascular causes (+1.8% (1.2% to 2.5%)) and myocardial infarction (+1.1% (0.7% to 1.5%)), but comparatively high for arrhythmias (+5.0% (3.2% to 6.9%)) and pulmonary heart disease (+8.3% (2.7% to 14.3%)). Among non- cardiorespiratory causes, the strongest effects were for genitourinary (+3.8% (2.9% to 4.7%)) and nervous system (+4.6% (3.7% to 5.4%)) disorders. 33.9% of heat deaths were attributable to cardiovascular causes, 24.7% to respiratory causes and 41.3% to all other causes combined.

Conclusions

These results suggest that the risk of heat-related mortality is distributed across a wide range of different causes, and that targeting of preventative actions based on pre-existing disease is unlikely to be efficient.
Water disinfection by-products and bladder cancer: is there a European specificity? A pooled and meta-analysis of European case–control studies
Authors: Costet N , Villanueva C M , Jaakkola J J K , Kogevinas M , Cantor K P , King W D , Lynch C F , Nieuwenhuijsen M J , Cordier S
Published: March 2011

Several epidemiological studies suggested an association between the risk of bladder cancer and the exposure to trihalomethanes (THMs), the main disinfection by-products (DBPs) of chlorinated water. A previous pooled analysis of case-control studies from North America and Europe estimated a summarized dose-response relation. For policy guidance of drinking water disinfection in Europe and because major differences exist in water disinfection practices and DBPs occurrence between both continents, specific risk estimates for bladder cancer in relation to DBPs exposure for European populations were needed. We conducted a pooled and a two-stage random-effect meta-analyses of three European case-control studies from France, Finland, and Spain (5467 individuals: 2381 cases and 3086 controls). Individual exposure to THMs was calculated combining information on residential history, estimates of the average total THMs (TTHM) level in tap water at the successive residences and personal water consumption. A significant odds-ratio was observed for men exposed to an average residential TTHM level > 50 μg/l (OR=1.47 (1.05; 2.05)) when compared to men exposed to levels ≤ 5 μg/l. The linear trend of the exposure-risk association was significant (p=0.01). Risks increased significantly for exposure levels above 25 μg/l and with more than 30 years of exposure to chlorinated water, but were mainly driven by the level rather than the duration of exposure. No significant association was found among women or with cumulative exposure through ingestion. There was no evidence of a differential exposure-response relation for TTHM and bladder cancer in Europe and North America. Consequently, a global exposure-risk relation based on 4351 cases and 7055 controls is now available.
Comparison of three methods of injecting the proximal interphalangeal joint in horses
Authors: Poore L. A. B. , Lambert K. L. , Shaw D. J. , Weaver M. P.
Published: March 2011

The efficacy of three methods of injecting the equine proximal interphalangeal (pastern) joint was compared using cadaver limbs. Five veterinary students without prior experience attempted to inject an aqueous radiographic contrast medium into the joint using five limbs for each technique. The number of attempts was recorded and successful injection of the joint was confirmed by the presence of intra‐articular contrast on radiographic examination. Levels of accuracy for the dorsal, dorsolateral and palmaroproximal approaches were 32, 48 and 36 per cent, respectively. There was inadvertent injection of the digital flexor tendon sheath using the palmaroproximal approach in 64 per cent of injections. The dorsolateral approach was associated with fewer needle manipulations.
CIRCULAR GEODESICS IN SCHWARZSCHILD-LIKE SPACETIMES
Authors: RADOSZ A. , SIWEK A. , POLONYI J. , OSTASIEWICZ K.
Published: March 2011

A special solution of Hořava–Lifshitz gravity is a black hole that in a certain limit reproduces Schwarzschild spacetime. It is shown here that the common feature of this class of Schwarzschild-like spacetimes is the presence of three distinct, non-overlapping sectors of circular geodesics corresponding to three distinct types of objects. It is also found that a photon sphere which separates ordinary matter and tachyonic sectors turns out to be a point of no return for massive particles' geodesics.
THE SIMPLE NONDEGENERATE RELATIVISTIC GAS: STATISTICAL PROPERTIES AND BROWNIAN MOTION
Authors: SANDOVAL-VILLALBAZO A. , ARAGONÉS-MUÑOZ A. , GARCÍA-PERCIANTE A. L.
Published: March 2011

This paper shows a novel calculation of the mean square displacement of a classical Brownian particle in a relativistic thermal bath. Also, the thermodynamic properties of a nondegenerate simple relativistic gas are reviewed in terms of a treatment performed in velocity space.
THE PERFORMANCE OF A MICRO GAS BEARING WITH VELOCITY SLIP AT THE SOLID BOUNDARY
Authors: HAI HUANG , GUANG MENG
Published: March 2011

Considering the velocity slip effect of the gas film at the solid boundary, the performance of a micro gas bearing is given. For the length scale of the micro gas bearing, the gas flow in the bearing is dominated by the slip regime instead of the continuum one. With different slip models, the modified Reynold's equations are obtained. Solving the Reynold's equation with finite difference method, the bearing forces are compared between the different models, and the second order slip model is found to fit the microelectromechanical systems (MEMS) case very well. Adopting the second order slip model, the dynamical coefficients and the stable threshold speed of the system are estimated based on the linear bearing force. And the dynamical response of the micro gas bearing is acquired with fourth-rank Runge–Kutta method. Compared with the results of the second order slip flow, the continuum flow overestimates the dynamical coefficients and underestimates the threshold speed. What is more, the period of the journal oscillation rose for the slip effect.
STUDY OF MAGNETIC PROPERTIES OF DILUTED FERRIMAGNETIC SPINELS SYSTEMS BY: HIGH TEMPERATURE SERIES EXPANSIONS
Authors: MASROUR RACHID , HAMEDOUN MOHAMED , BENYOUSSEF ABDELILAH
Published: March 2011

The ferrimagnetic spinels systems Co x Fe 1-x Cr 2 S 4 has been studied by high-temperature series expansions method in the range 0 ≤x ≤1. The exchange interactions and exchange energies are calculated by using the probability law. The high-temperature series expansions have been applied in the spinels systems Co x Fe 1-x Cr 2 S 4, combined with the Padé approximants method, to determine the magnetic phase diagram, i.e., TC versus dilution x. The critical exponent associated with the magnetic susceptibility (γ) is deduced.
LINEAR AND NONLINEAR GENERALIZED SYNCHRONIZATION OF CHAOTIC SYSTEMS
Authors: WANG XING-YUAN , ZHANG JING
Published: March 2011

In this paper, the linear and nonlinear generalized synchronization of chaotic systems is investigated. Based on the modified state observer method, a new synchronization approach is proposed with more extensive application scope. The proposed synchronization scheme can realize the linear and nonlinear generalized synchronizations of same dimensional or different dimensional chaotic systems. Sufficient conditions of global asymptotic generalized synchronization between the drive system and the response system are gained on the basis of the state observer theory. Numerical simulations further illustrate the effectiveness of the proposed scheme.
ESR OF A MAGNETIC PROBE IN THE NEIGHBORHOOD OF AN ANDERSON IMPURITY
Authors: PINTO J. W. M. , FROTA H. O.
Published: March 2011

The renormalization group formalism was applied to calculate the spin lattice relaxation rate [Formula: see text] of a magnetic probe located in the neighborhood of a spin degenerate Anderson impurity. In the Kondo regime, [Formula: see text] as a function of the temperature T presents a peak at the Kondo temperature TK. For T≪TK, the system behaves as a heavy Fermi liquid, with an enhanced density of states, which increases with the decrease in the Kondo temperature; [Formula: see text] is a universal function of T/ΓK up to temperatures of the order of 100 ΓK, where ΓK is the Kondo width for temperatures lower than TK. The spin relaxation rate [Formula: see text] is proportional to the product of the magnetic susceptibility and temperature χT. Moreover, in the peak, [Formula: see text] at the Kondo temperature decreases with the increase in the distance between the Anderson impurity and the magnetic probe.
FOUR QUADRANT ANALOG MULTIPLIER USING DUAL-CURRENT-CONTROLLED CURRENT DIFFERENCING BUFFERED AMPLIFIER
Authors: LAHIRI ABHIRUP , CHOWDHURY ANKUSH
Published: March 2011

A novel four quadrant analog multiplier (FQAM) is presented using the recently proposed active building block (ABB), namely the dual-current-controlled current differencing buffered amplifier (DCC-CDBA). The inputs to the circuit are two bipolar current signals and current and voltage outputs are available as multiplication of the input signals. The use of DCC-CDBA in four quadrant multiplier design is attractive, since the circuit structure is very simple and uses reduced number of components, viz. only one DCC-CDBA, which is constructed using two second-generation current controlled conveyors (CCCIIs). The circuit operation is current-tunable and ideally temperature insensitive. The workability of the circuit is verified using PSPICE simulations.
A FPGA CORE GENERATOR FOR EMBEDDED CLASSIFICATION SYSTEMS
Authors: ANGUITA DAVIDE , CARLINO LUCA , GHIO ALESSANDRO , RIDELLA SANDRO
Published: March 2011

We describe in this work a Core Generator for Pattern Recognition tasks. This tool is able to generate, according to user requirements, the hardware description of a digital architecture, which implements a Support Vector Machine, one of the current state-of-the-art algorithms for Pattern Recognition. The output of the Core Generator consists of a high-level language hardware core description, suitable to be mapped on a reconfigurable device, like a Field Programmable Gate Array (FPGA). As an example of the use of our tool, we compare different solutions, by targeting several reconfigurable devices, and implement the recognition part of a machine vision system for automotive applications.
NEW CONCEPT OF 3.2–4.8 GHz IMPULSE GENERATOR FOR UWB TRANSMITTER
Authors: ISSA DALENDA BEN , KACHOURI ABDENNACEUR , SAMET MOUNIR
Published: March 2011

A new design of Ultra-Wide band (UWB) generator is described in this paper. The UWB impulse generator circuit is the most essential block in a mono-band UWB transmitter. The proposed ultra wide band impulse generator circuit utilizes the performances of the CMOS technology effectively, it is composed of a voltage controlled oscillator (VCO), and a rectangular pulse generator (RPG) and mixer. The RPG circuit consists of a frequency divider 1/128 circuit, time delay, N-inverters and AND gate function. The impulse UWB generator is based on the rectangular pulse modulated with the aim of generating the UWB impulse signal. This proposed circuit generates an output signal which is defined by the bandwidth of 1.6 GHz at centered frequency of 4 GHz and the limited Power Spectral Density (PSD) is −41.47 dBm/MHz. The peak-to-peak amplitude of the UWB impulse signal is 528 mV, the output impulse width of 2 ns and the impulse repetition period (PRP) is 32 ns. The power consumption is about 12.5 mW at 2.5 V voltage supply.
CASCADABLE ALL-PASS AND NOTCH FILTER CONFIGURATIONS EMPLOYING TWO PLUS-TYPE DDCCs
Authors: MAHESHWARI SUDHANSHU , MOHAN JITENDRA , CHAUHAN DURG SINGH
Published: March 2011

In this paper, twelve new circuit configurations for realization of first-order, second-order voltage-mode all-pass and notch filters with high input impedance and low output impedance are presented. The proposed circuit configurations use two plus type DDCCs, and two impedances. The circuits use one grounded capacitor and two grounded resistors for realizing first-order all-pass filters, and two grounded capacitors and two resistors for realizing second-order all-pass/notch filters. High input impedance and low output impedance of the configuration enable the circuits to be cascaded without additional buffers. As an application, a quadrature oscillator is realized. The theoretical results are verified with PSPICE simulations using 0.5 μm CMOS parameters.
THE STRUCTURE OF INVARIANT TORI IN A 3D GALACTIC POTENTIAL
Authors: KATSANIKAS M. , PATSIS P. A.
Published: March 2011

We study in detail the structure of phase space in the neighborhood of stable periodic orbits in a rotating 3D potential of galactic type. Using the color and rotation method to investigate the properties of the invariant tori in 4D spaces of the section, we compare our results with those of previous works and we describe the morphology of the rotational, as well as of the tube tori in 4D space. We find sticky chaotic orbits in the immediate neighborhood of sets of invariant tori surrounding 3D stable periodic orbits. Particularly useful for galactic dynamics is the behavior of chaotic orbits trapped for long time between 4D invariant tori. We find that they support during this time the same structure as the quasi-periodic orbits around the stable periodic orbits, contributing however to a local increase of the dispersion of velocities. Finally, we find that the tube tori do not appear in the 3D projections of the spaces of the section in the axisymmetric Hamiltonian we examined.
VALIDATED STUDY OF THE EXISTENCE OF SHORT CYCLES FOR CHAOTIC SYSTEMS USING SYMBOLIC DYNAMICS AND INTERVAL TOOLS
Authors: GALIAS ZBIGNIEW , TUCKER WARWICK
Published: March 2011

We show that, for a certain class of systems, the problem of establishing the existence of periodic orbits can be successfully studied by a symbolic dynamics approach combined with interval methods. Symbolic dynamics is used to find approximate positions of periodic points, and the existence of periodic orbits in a neighborhood of these approximations is proved using an interval operator. As an example, the Lorenz system is studied; a theoretical argument is used to prove that each periodic orbit has a distinct symbol sequence. All periodic orbits with the period p ≤ 16 of the Poincaré map associated with the Lorenz system are found. Estimates of the topological entropy of the Poincaré map and the flow, based on the number and flow-times of short periodic orbits, are calculated. Finally, we establish the existence of several long periodic orbits with specific symbol sequences.
EXISTENCE AND COMPUTATION OF TOURS THROUGH IMPRECISE POINTS
Authors: LÖFFLER MAARTEN
Published: March 2011

Assume that an ordered set of imprecise points is given, where each point is specified by a region in which the point may lie. This set determines an imprecise polygon. We show that it is NP-hard to decide whether it is possible to place the points inside their regions in such a way that the resulting polygon is simple. Furthermore, it is NP-hard to minimize the length of a simple tour visiting the regions in order, when the connections between consecutive regions are not needed to be straight line segments. We also present two linear-time algorithms to compute the shortest and longest possible tour for the case where the polygon is not required to be simple and the regions are squares.
COMPUTATIONAL AND STRUCTURAL ADVANTAGES OF CIRCULAR BOUNDARY REPRESENTATION
Authors: AICHHOLZER OSWIN , AURENHAMMER FRANZ , HACKL THOMAS , JÜTTLER BERT , RABL MARGOT , ŠÍR ZBYNEK
Published: March 2011

Boundary approximation of planar shapes by circular arcs has quantitative and qualitative advantages compared to using straight-line segments. We demonstrate this by way of three basic and frequent computations on shapes – convex hull, decomposition, and medial axis. In particular, we propose a novel medial axis algorithm that beats existing methods in simplicity and practicality, and at the same time guarantees convergence to the medial axis of the original shape.
A COMPLETE ALGORITHM FOR SEARCHLIGHT SCHEDULING
Authors: OBERMEYER KARL J. , GANGULI ANURAG , BULLO FRANCESCO
Published: March 2011

This article develops an algorithm for a group of guards statically positioned in a non-convex polygonal environment with holes. Each guard possesses a single searchlight, a ray sensor which can rotate about the guard's position but cannot penetrate the boundary of the environment. A point is detected by a searchlight if and only if the point is on the ray at some instant. Targets are points which move arbitrarily fast. The objective of the proposed algorithm is to compute a schedule to rotate a set of searchlights in such a way that any target in an environment will necessarily be detected in finite time. This is known as the Searchlight Scheduling Problem and was described originally in 1990 by Sugihara et al. We take an approach known as exact cell decomposition in the motion planning literature. The algorithm operates by decomposing the searchlights' joint configuration space and the environment, and then by constructing a so-called information graph. Searching the information graph for a path between desired states yields a search schedule. We also introduce a new problem called the ϕ-Searchlight Scheduling Problem in which ϕ-searchlights sense not just along a ray, but over a finite field of view. We show that our results for searchlight scheduling can be directly extended for ϕ-searchlight scheduling. Proofs of completeness, complexity bounds, and computed examples are presented.
SOLVING CONSTRAINED GLOBAL OPTIMIZATION VIA ARTIFICIAL IMMUNE SYSTEM
Authors: WU JUI-YU
Published: March 2011

Artificial immune systems (AISs) are computational intelligence (CI) oriented methods using information based on biological immune systems. In this study, an AIS, which combines the metaphor of clonal selection with idiotypic network theories, is developed. Although they are contradictory approaches, clonal selection and idiotypic network may prove useful in designing a stochastic global optimization tool. The AIS method consists of idiotypic network selection, somatic hypermuation, receptor editing and bone marrow operators. The idiotypic network selection operator determines the number of good solutions. The somatic hypermutation and receptor editing operators comprise the searching mechanisms for the exploration of the solution space. Diversity on the population of solutions is ensured by the bone marrow operator. The performance of the proposed AIS method is tested on a set of global constrained optimization problems (GCO), comprising of four benchmark nonlinear programming problems and four generalized polynomial programming (GPP) problems, where GPP problems are nonconvex optimization problems. The best solution found by the AIS algorithm is compared with the known global optimum. Numerical results show that the proposed method converged to the global optimal solution to each tested CGO problem. Moreover, this study compares the numerical results obtained by the AIS approach with those taken from published CI approaches, such as alternative AIS methods and genetic algorithms.
DIRECT ALGORITHMS FOR FINDING MINIMAL UNSATISFIABLE SUBSETS IN OVER-CONSTRAINED CSPs
Authors: SHAH I.
Published: March 2011

In many situations, an explanation of the reasons behind inconsistency in an overconstrained CSP is required. This explanation can be given in terms of minimal unsatisfiable subsets (MUSes) of constraints. This paper presents algorithms for finding minimal unsatisfiable subsets (MUSes) of constraints in overconstrained CSPs with finite domains and binary constraints. The approach followed is to generate subsets in the subset space, test them for consistency and record the inconsistent subsets found. We present three algorithms as variations of this basic approach. Each algorithm generates subsets in the subset space in a different order and curtails search by employing various search pruning mechanisms. The proposed algorithms are anytime algorithms: a time limit can be set on an algorithm's search and the algorithm can be made to find a subset of MUSes. Experimental evaluation of the proposed algorithms demonstrates that they perform two to three orders of magnitude better than the existing indirect algorithms. Furthermore, the algorithms are able to find MUSes in large CSP benchmarks.
FINDING REPRESENTATIVE WEB PAGES BASED ON A SOM AND A REVERSE CLUSTER ANALYSIS
Authors: RÍOS SEBASTIÁN A. , VELÁSQUEZ JUAN D.
Published: March 2011

Enhancing the content and structure of a web site is a very important task which can help to maintain people visiting a web site and gain new visits (or customers). Web mining area helps to enhance a web site organization and contents using data mining algorithms. In particular we may perform Web Mining using a Self Organizing Feature Map (SOFM or SOM) it is always needed an analysis phase by experts. To help analysts to perform this phase after SOFMs' training, many post-processing techniques have been developed (component planes, labels, etc.); however, none of these techniques are useful when working in web mining for off-line enhancements of a web site. In this paper an algorithm called Reverse Cluster Analysis (RCA) will be provided. It aims to identify important web pages based on a self organizing feature map (SOFM) when performing web text mining (WTM) and web usage mining (WUM). We successfully applied this technique in a real web site to show its effectiveness. We have extended previous work performing a comparison with another unsupervised technique, administrators survey and an extended survey.
CLUSTERING WITH MINIMUM SPANNING TREES
Authors: ZHOU YAN , GRYGORASH OLEKSANDR , HAIN THOMAS F.
Published: March 2011

We propose two Euclidean minimum spanning tree based clustering algorithms — one a k-constrained, and the other an unconstrained algorithm. Our k-constrained clustering algorithm produces a k-partition of a set of points for any given k. The algorithm constructs a minimum spanning tree of a set of representative points and removes edges that satisfy a predefined criterion. The process is repeated until k clusters are produced. Our unconstrained clustering algorithm partitions a point set into a group of clusters by maximally reducing the overall standard deviation of the edges in the Euclidean minimum spanning tree constructed from a given point set, without prescribing the number of clusters. We present our experimental results comparing our proposed algorithms with k-means, X-means, CURE, Chameleon, and the Expectation-Maximization (EM) algorithm on both artificial data and benchmark data from the UCI repository. We also apply our algorithms to image color clustering and compare them with the standard minimum spanning tree clustering algorithm as well as CURE, Chameleon, and X-means.
MENDÈS FRANCE AND THERMODYNAMICAL SPECTRA: A COMPARATIVE STUDY OF CONTRACTIVE AND EXPANSIVE FRACTAL PROCESSES
Authors: PIACQUADIO MARÍA N. , HANSEN ROBERTA
Published: March 2011

This paper presents a comparative study of two families of curves in ℝn. The first ones comprise self-similar bounded fractals obtained by contractive processes, and have a non-integer Hausdorff dimension. The second ones are unbounded, locally rectifiable, locally smooth, obtained by expansive processes, and characterized by a fractional dimension defined by M. Mendès France. We present a way to relate the two types of curves and their respective non-integer dimensions. Thus, to one fractal bounded curve we associate, at first, a finite range of Mendès France dimensions, identifying the minimal and the maximal ones. Later, we show that this discrete spectrum can be made continuous, allowing it to be compared with some other multifractal spectra encountered in the literature. We discuss the corresponding physical interpretations.
CALCULUS ON FRACTAL CURVES IN Rn
Authors: PARVATE ABHAY , SATIN SEEMA , GANGAL A. D.
Published: March 2011

A new calculus on fractal curves, such as the von Koch curve, is formulated. We define a Riemann-like integral along a fractal curve F, called Fα-integral, where α is the dimension of F. A derivative along the fractal curve called Fα-derivative, is also defined. The mass function, a measure-like algorithmic quantity on the curves, plays a central role in the formulation. An appropriate algorithm to calculate the mass function is presented to emphasize its algorithmic aspect.

Several aspects of this calculus retain much of the simplicity of ordinary calculus. We establish a conjugacy between this calculus and ordinary calculus on the real line. The Fα-integral and Fα-derivative are shown to be conjugate to the Riemann integral and ordinary derivative respectively. In fact, they can thus be evalutated using the corresponding operators in ordinary calculus and conjugacy. Sobolev Spaces are constructed on F, and Fα-differentiability is generalized. Finally we touch upon an example of absorption along fractal paths, to illustrate the utility of the framework in model making.
BEZIER AND B-SPLINE CURVES WITH KNOTS IN THE COMPLEX PLANE
Authors: TSIANOS KONSTANTINOS I. , GOLDMAN RON
Published: March 2011

We extend some well known algorithms for planar Bezier and B-spline curves, including the de Casteljau subdivision algorithm for Bezier curves and several standard knot insertion procedures (Boehm's algorithm, the Oslo algorithm, and Schaefer's algorithm) for B-splines, from the real numbers to the complex domain. We then show how to apply these polynomial and piecewise polynomial algorithms in a complex variable to generate many well known fractal shapes such as the Sierpinski gasket, the Koch curve, and the C-curve. Thus these fractals also have Bezier and B-spline representations, albeit in the complex domain. These representations allow us to change the shape of a fractal in a natural manner by adjusting their complex Bezier and B-spline control points. We also construct natural parameterizations for these fractal shapes from their Bezier and B-spline representations.
MONETARY VALUATION OF CASH FLOWS UNDER KNIGHTIAN UNCERTAINTY
Authors: FÖLLMER HANS , PENNER IRINA
Published: March 2011

The classical valuation of an uncertain cash flow in discrete time consists in taking the expectation of the sum of the discounted future payoffs under a fixed probability measure, which is assumed to be known. Here we discuss the valuation problem in the context of Knightian uncertainty. Using results from the theory of convex risk measures, but without assuming the existence of a global reference measure, we derive a robust representation of concave valuations with an infinite time horizon, which specifies the interplay between model uncertainty and uncertainty about the time value of money.
CONDITIONAL CERTAINTY EQUIVALENT
Authors: FRITTELLI MARCO , MAGGIS MARCO
Published: March 2011

In a dynamic framework, we study the conditional version of the classical notion of certainty equivalent when the preferences are described by a stochastic dynamic utility u(x,t,ω). We introduce an appropriate mathematical setting, namely Orlicz spaces determined by the underlying preferences and thus provide a systematic method to go beyond the case of bounded random variables. Finally we prove a conditional version of the dual representation which is a crucial prerequisite for discussing the dynamics of certainty equivalents.
INITIAL INVESTMENT CHOICE AND OPTIMAL FUTURE ALLOCATIONS UNDER TIME-MONOTONE PERFORMANCE CRITERIA
Authors: MUSIELA M. , ZARIPHOPOULOU T.
Published: March 2011

The paper offers a new perspective on optimal portfolio choice by investigating how and to what extent knowledge of an investor's desirable initial investment choice can be used to determine his future optimal portfolio allocations. Optimality of investment decisions is built on the so-called forward investment performance criteria and, in particular, on the time-monotone ones. It is shown that for this class of forward criteria the desired initial allocations completely characterize the future optimal investment strategies. The analysis uses the connection between a nonlinear equation, satisfied by the local risk tolerance, and the backward heat equation. Complete solutions are provided as well as various examples.
COMPOSITION OF TIME-CONSISTENT DYNAMIC MONETARY RISK MEASURES IN DISCRETE TIME
Authors: CHERIDITO PATRICK , KUPPER MICHAEL
Published: March 2011

In discrete time, every time-consistent dynamic monetary risk measure can be written as a composition of one-step risk measures. We exploit this structure to give new dual representation results for time-consistent convex monetary risk measures in terms of one-step penalty functions. We first study risk measures for random variables modelling financial positions at a fixed future time. Then we consider the more general case of risk measures that depend on stochastic processes describing the evolution of financial positions or cumulated cash flows. In both cases the new representations allow for a simple composition of one-step risk measures in the dual. We discuss several explicit examples and provide connections to the recently introduced class of dynamic variational preferences.
QUANTIZATION NOISE IN STATISTICAL KEY EXCHANGE
Authors: LIU PAO-LO , JOSAN MADHUR S.
Published: March 2011

Ideally, signals in statistical key exchange should be band-limited to prevent leak. During digitization, however, the broadband quantization noise gets incorporated. In this study, the security risk posed by the quantization noise is analyzed. The Savitzky–Golay filtering technique is used to reduce the quantization noise. Although the noise can be reduced, it cannot be eliminated. Legitimate users must take evasive measures. The adversary can perform exhaustive search. Once how signals are processed is identified, the security can be breached.
SVM-BASED METHOD FOR PROTEIN STRUCTURAL CLASS PREDICTION USING SECONDARY STRUCTURAL CONTENT AND STRUCTURAL INFORMATION OF AMINO ACIDS
Authors: MOHAMMAD TABREZ ANWAR SHAMIM , NAGARAJARAM HAMPAPATHALU ADIMURTHY
Published: March 2011

The knowledge collated from the known protein structures has revealed that the proteins are usually folded into the four structural classes: all-α, all-β, α/β and α + β. A number of methods have been proposed to predict the protein's structural class from its primary structure; however, it has been observed that these methods fail or perform poorly in the cases of distantly related sequences. In this paper, we propose a new method for protein structural class prediction using low homology (twilight-zone) protein sequences dataset. Since protein structural class prediction is a typical classification problem, we have developed a Support Vector Machine (SVM)-based method for protein structural class prediction that uses features derived from the predicted secondary structure and predicted burial information of amino acid residues. The examination of different individual as well as feature combinations revealed that the combination of secondary structural content, secondary structural and solvent accessibility state frequencies of amino acids gave rise to the best leave-one-out cross-validation accuracy of ~81% which is comparable to the best accuracy reported in the literature so far.
Incision rate of the Yellow River in Northeastern Tibet constrained by
10
Be and
26
Al cosmogenic isotope dating of fluvial terraces: implications for catchment evolution and plateau building
Authors: Perrineau A. , Woerd J. Van Der , Gaudemer Y. , Liu-Zeng Jing , Pik R. , Tapponnier P. , Thuizat R. , Rongzhang Zheng
Published: March 2011

Unlike other large rivers flowing out of Tibet, the Yellow River escapes from the plateau towards the NE crossing no less than five NW–SE striking, actively growing ranges and intervening basins. Thick Plio-Quaternary deposits and fluvial terraces testify to a phase of aggradation and sediment infill up to the average surface elevation (3200–3250 m a.s.l.) of the Gonghe, Guide and Qinghai Lake basins. A set of seven main terraces across the Gonghe Basin suggests progressive down-cutting of the Yellow River carving the 500 m deep Longyang gorge at the basin exit.
10
Be and
26
Al concentrations in quartz of surface and sub-surface samples of four terraces constrain the timing of incision by determining the burial age of the deposit and the exposure age of its surface. Modelling the depth dependence of the
10
Be concentration and the
26
Al/
10
Be ratio allows us to constrain the onset of the ongoing phase of incision to 120–250 ka. These ages suggest long-term incision rates between 2–6 mm a
−1
. Together with the present morphology of the Yellow River terraces across the Gonghe basin and the Longyang gorge, our results imply rapid river catchment evolution and interaction between river dynamics, tectonic and climate in northeastern Tibet.
Discontinuous low-velocity zones in southern Tibet question the viability of the channel flow model
Authors: Hetényi György , Vergne Jérôme , Bollinger Laurent , Cattin Rodolphe
Published: March 2011

Low-velocity zones (‘bright spots’) imaged by the INDEPTH seismic experiment in southern Tibet are extensively interpreted as widespread partial melt within the crust, which has given a strong support for the channel flow model. These suggest that a continuous seismic low-velocity zone underlies Tibet on the large scale. Here we take advantage of the Hi-CLIMB seismic experiment which includes a dense south–north profile and a lateral 2D seismic network to assess the vertical and the horizontal extension of low-velocity zones in southern Tibet. Several approaches including migration, amplitude analysis and waveform inversion of receiver functions are performed to detect crustal low-velocity zones using this new seismological dataset. Our results reveal localized and discontinuous low-velocity zones in Tibet. They indicate that the vertical extension of the low-velocity zones is about 10 km, and their maximum horizontal length appears to be
c
. 50 km. Our study suggests a partial correlation between the location of these low-velocity zones and the spatial distribution of Tibetan grabens. These results, especially the non-continuity of low-velocity zones, together with the observed regular value of mean crustal V
P
/V
S
ratio, question the existence of widespread partial melt of the southern Tibetan crust and, therefore, the viability of the channel flow model.
The seismological structure of the Tibetan Plateau crust and mantle down to 700 km depth
Authors: Mechie J. , Kind R. , Saul J.
Published: March 2011

A seismic velocity cross-section down to 700 km depth beneath the Tibetan Plateau has been constructed. Beneath the cover layer, felsic rocks rich in α quartz exist down to 15–25 km depth. Beneath these depths, temperatures are probably high enough for ductile flow and partial melting to occur. The velocity increase across the boundary at 30–40 km depth marks the interface between felsic upper crust and more mafic lower crust. Crustal thickness is greatest (
c
. 74 km) south of
c
. 31.5°N, where Indian lower crust forms the basal layer. Northwards, crustal thickness decreases to
c
. 66 km around 33°N, before increasing to
c
. 70 km beneath northern Tibet. Crossing the Kunlun, the crust thins to
c
. 54 km beneath the Qaidam basin. High-velocity, dense, cold Indian lithospheric mantle extends northwards until about the Banggong-Nujiang suture, where it downwells to 350–400 km depth. The lithosphere–asthenosphere boundary occurs at 160–225 km depth. The apparent northwards deepening of the 410 and 660 km discontinuities implies that the upper mantle beneath northern Tibet is slower, less dense and warmer than under southern Tibet which, in turn, could provide some of the isostatic support for the high elevations in northern Tibet where the crust is thinner than under southern Tibet.
Parathyroid hormone (PTH) rapidly enhances CFTR-mediated HCO3− secretion in intestinal epithelium-like Caco-2 monolayer: a novel ion regulatory action of PTH
Authors: Laohapitakworn Suparerk , Thongbunchoo Jirawan , Nakkrasae La-iad , Krishnamra Nateetip , Charoenphandhu Narattaphol
Published: March 2011

Besides being a Ca2+-regulating hormone, parathyroid hormone (PTH) has also been shown to regulate epithelial transport of certain ions, such as Cl−, HCO3−, and Na+, particularly in the kidney. Although the intestinal epithelium also expressed PTH receptors, little was known regarding its mechanism in the regulation of intestinal ion transport. We investigated the ion regulatory role of PTH in intestinal epithelium-like Caco-2 monolayer by Ussing chamber technique and alternating current impedance spectroscopy. It was found that Caco-2 cells rapidly responded to PTH within 1 min by increasing apical HCO3− secretion. CFTR served as the principal route for PTH-stimulated apical HCO3− efflux, which was abolished by various CFTR inhibitors, namely, NPPB, glycine hydrazide-101 (GlyH-101), and CFTRinh-172, as well as by small interfering RNA against CFTR. Concurrently, the plasma membrane resistance was decreased with no changes in the plasma membrane capacitance or paracellular permeability. HCO3− was probably supplied by basolateral uptake via the electrogenic Na+-HCO3− cotransporter and by methazolamide-sensitive carbonic anhydrase, while the resulting intracellular H+ might be extruded by both apical and basolateral Na+/H+ exchangers. Furthermore, the PTH-stimulated HCO3− secretion was markedly reduced by protein kinase A (PKA) inhibitor (PKI 14–22 amide) and phosphoinositide 3-kinase (PI3K) inhibitors (wortmannin and LY-294002), but not by intracellular Ca2+ chelator (BAPTA-AM) or protein kinase C inhibitor (GF-109203X). In conclusion, the present study provided evidence that PTH directly and rapidly stimulated apical HCO3− secretion through CFTR in PKA- and PI3K-dependent manner, which was a novel noncalciotropic, ion regulatory action of PTH in the intestinal epithelium.
p300 Acetyltransferase activity differentially regulates the localization and activity of the FOXO homologues in skeletal muscle
Authors: Senf Sarah M. , Sandesara Pooja B. , Reed Sarah A. , Judge Andrew R.
Published: March 2011

The Forkhead Box O (FOXO) transcription factors regulate diverse cellular processes, and in skeletal muscle are both necessary and sufficient for muscle atrophy. Although the regulation of FOXO by Akt is well evidenced in skeletal muscle, the current study demonstrates that FOXO is also regulated in muscle via the histone acetyltransferase (HAT) activities of p300/CREB-binding protein (CBP). Transfection of rat soleus muscle with a dominant-negative p300, which lacks HAT activity and inhibits endogenous p300 HAT activity, increased FOXO reporter activity and induced transcription from the promoter of a bona fide FOXO target gene, atrogin-1. Conversely, increased HAT activity via transfection of either wild-type (WT) p300 or WT CBP repressed FOXO activation in vivo in response to muscle disuse, and in C2C12 cells in response to dexamethasone and acute starvation. Importantly, manipulation of HAT activity differentially regulated the expression of various FOXO target genes. Cotransfection of FOXO1, FOXO3a, or FOXO4 with the p300 constructs further identified p300 HAT activity to also differentially regulate the activity of the FOXO homologues. Markedly, decreased HAT activity strongly increased FOXO3a transcriptional activity, while increased HAT activity repressed FOXO3a activity and prevented its nuclear localization in response to nutrient deprivation. In contrast, p300 increased FOXO1 nuclear localization. In summary, this study provides the first evidence to support the acetyltransferase activities of p300/CBP in regulating FOXO signaling in skeletal muscle and suggests that acetylation may be an important mechanism to differentially regulate the FOXO homologues and dictate which FOXO target genes are activated in response to varying atrophic stimuli.
Lipid raft-dependent activation of dual oxidase 1/H2O2/NF-κB pathway in bronchial epithelial cells
Authors: Wang Lifen , Zhen Hongtao , Yao Wanjing , Bian Fang , Zhou Fan , Mao Xiaofang , Yao Ping , Jin Si
Published: March 2011

The present study addressed whether dual oxidase 1 (Duox1), a predominant isoform of NADPH oxidase in bronchial epithelial cells, is also activated through assembling of Duox1 and its partners such as p47 phox due to lipid raft (LR) clustering. By gradient ultracentrifugation to isolate LR fractions in bronchial epithelial cells, it was found that Duox1 or p47 phox was translocated into LR fractions when stimulated by tumor necrosis factor-α (TNF-α). Confocal microscopic analysis revealed that LRs were aggregated or clustered in the membrane, which were colocalized with Duox1 or p47 phox. Ceramide, a hydrolysis product of sphingomyelin, was also found colocalized with Duox1 or p47 phox upon stimulation. In the presence of the commonly used LR disruptor, methyl-β-cyclodextrin (MCD), or the acid sphingomyelinase (ASMase) inhibitor, desipramine (DES), TNF-α-stimulated aggregation, translocation, and colocalization of LR components and Duox1 or its partners was abolished. Functionally, TNF-α-stimulated H2O2 production was also blocked by MCD and DES (194.6 ± 15.4% vs. 90.6 ± 15.9% and 148.8 ± 20.4%), and the activation of the pivotal proinflammatory transcription factor, NF-κB, by TNF-α was reversed by MCD and DES as well as by small interfering RNAs of Duox1 or ASMase. Our results for the first time demonstrate that Duox1-mediated redox signaling in bronchial epithelial cells is associated with LR clustering dependent on the production of ceramide through ASMase.
Increased contractility of hepatic stellate cells in cirrhosis is mediated by enhanced Ca2+-dependent and Ca2+-sensitization pathways
Authors: Iizuka Masateru , Murata Takahisa , Hori Masatoshi , Ozaki Hiroshi
Published: March 2011

Activation of hepatic stellate cells (HSCs) results in cirrhosis and portal hypertension due to intrahepatic resistance. Activated HSCs increase their contraction after receptor agonist stimulation; however, the signaling pathways for the regulation of contraction are not fully understood. The aim of this study was to elucidate the change in contractile mechanisms of HSCs after cirrhotic activation. The expression pattern of contractile regulatory proteins was analyzed with quantitative RT-PCR and Western blotting. The phosphorylation levels of myosin light chain (MLC), 17-kDa PKC-potentiated protein phosphatase 1 inhibitor protein (CPI-17), and MLC phosphatase targeting subunit 1 (MYPT1) after endothelin-1 (ET-1) stimulation in culture-activated HSCs were measured using phosphorylation-specific antibodies. In vivo-activated HSCs were isolated from rats subjected to bile duct ligation and repeated dimethylnitrosoamine injections. HSCs showed increased expression of not only α-smooth muscle actin, but also the contractile regulatory proteins MLC kinase (MLCK), Rho kinase 2 (ROCK2), and CPI-17 during HSC activation in vitro. In culture-activated HSCs, ET-1 increased phosphorylation of CPI-17 at Thr18, which was markedly inhibited by the PKC inhibitor Ro-31–8425. ET-1 induced phosphorylation of MYPT1 at Thr853, which was suppressed by the ROCK inhibitor Y-27632. ET-1 induced sustained phosphorylation of MLC at Thr18/Ser19, which was inhibited by both Ro-31–8425 and Y-27632. Consistent with the data obtained from the in vitro study, HSCs isolated from cirrhotic rats showed increased expression of α-smooth muscle actin, MLCK, CPI-17, and ROCK2 compared with HSCs from nontreated rats. Furthermore, MLC phosphorylation in in vivo-activated HSCs was increased, according to enhanced phosphorylation of CPI-17 and MYPT1 in the presence of ET-1. These results suggest that activated HSCs may participate in constriction of hepatic sinusoids in the cirrhotic liver through both Ca2+-dependent (MLCK pathway) and Ca2+-sensitization mechanism (CPI-17 and MYPT1 pathways).
Rat diaphragm mitochondria have lower intrinsic respiratory rates than mitochondria in limb muscles
Authors: Garcia-Cazarin Mary L. , Gamboa Jorge L. , Andrade Francisco H.
Published: March 2011

The mitochondrial content of skeletal muscles is proportional to activity level, with the assumption that intrinsic mitochondrial function is the same in all muscles. This may not hold true for all muscles. For example, the diaphragm is a constantly active muscle; it is possible that its mitochondria are intrinsically different compared with other muscles. This study tested the hypothesis that mitochondrial respiration rates are greater in the diaphragm compared with triceps surae (TS, a limb muscle). We isolated mitochondria from diaphragm and TS of adult male Sprague Dawley rats. Mitochondrial respiration was measured by polarography. The contents of respiratory complexes, uncoupling proteins 1, 2, and 3 (UCP1, UCP2, and UCP3), and voltage-dependent anion channel 1 (VDAC1) were determined by immunoblotting. Complex IV activity was measured by spectrophotometry. Mitochondrial respiration states 3 (substrate and ADP driven) and 5 (uncoupled) were 27 ± 8% and 24 ± 10%, respectively, lower in diaphragm than in TS ( P < 0.05 for both comparisons). However, the contents of respiratory complexes III, IV, and V, UCP1, and VDAC1 were higher in diaphragm mitochondria (23 ± 6, 30 ± 8, 25 ± 8, 36 ± 15, and 18 ± 8% respectively, P ≤ 0.04 for all comparisons). Complex IV activity was 64 ± 16% higher in diaphragm mitochondria ( P ≤ 0.01). Mitochondrial UCP2 and UCP3 content and complex I activity were not different between TS and diaphragm. These data indicate that diaphragm mitochondria respire at lower rates, despite a higher content of respiratory complexes. The results invalidate our initial hypothesis and indicate that mitochondrial content is not the only determinant of aerobic capacity in the diaphragm. We propose that UCP1 and VDAC1 play a role in regulating diaphragm aerobic capacity.