bluuebunny/crossref_metadata_2025 huggingface dataset:
Weekend admissions as an independent predictor of mortality: an analysis of Scottish hospital admissions
Authors: Handel Adam E , Patel Sunil V , Skingsley Andrew , Bramley Katrina , Sobieski Roma , Ramagopalan Sreeram V
Published: November 2012

Objectives

Weekend admissions have been shown to be associated with an increased risk of mortality compared with weekday admissions for many diagnoses. We analysed emergency department admissions within the Scottish National Health Service to investigate whether mortality is increased in case of weekend emergency department admissions.

Design

A cohort study.

Setting

Scotland National Health Service (NHS) emergency departments.

Participants

5 271 327 emergency department admissions between 1999 and 2009. We included all patients admitted via emergency departments recorded in the Scottish Morbidity Records (SMR01) in NHS, Scotland for whom complete demographic data were available.

Primary outcome measures

Death as recorded by the General Register Office (GRO).

Results

There was a significantly increased probability of death associated with a weekend emergency admission compared with admission on a weekday (unadjusted OR 1.27, 95% CI 1.26 to 1.28, p<0.0001; adjusted for year of admission, gender, age, deprivation quintile and number of comorbidities OR 1.42, 95% CI 1.40 to 1.43, p<0.0001).

Conclusions

Despite a general reduction in mortality over the last 11 years, there is still a significant excess mortality associated with weekend emergency admissions. Further research should be undertaken to identify the precise mechanisms underlying this effect so that measures can be put in place to reduce patient mortality.
Genetic and epigenetic markers in the evaluation of pancreatic masses
Authors: Ginestà Mireia M , Mora Josefina , Mayor Regina , Farré Antoni , Peinado Miquel Angel , Busquets Juli , Serrano Teresa , Capellá Gabriel , Fabregat Joan
Published: November 2012

Background

Methylation markers have shown promise in the early diagnosis of pancreatic carcinoma. The aim of this study was to assess the diagnostic utility of hypermethylation status of candidate genes in combination withKRASmutation detection in the evaluation of pancreatic masses.

Experimental design

Sixty-one fine needle aspirates of pancreatic masses (43 pancreatic adenocarcinomas and 18 chronic pancreatitis) were studied. Methylation status ofHRH2,EN1,SPARC,CDH13andAPCwere analysed using melting curve analysis after DNA bisulfite treatment.KRASmutations were also analysed.

Results

The methylation panel had a sensitivity of 73% (27 of 37, CI 95% 56 to 86%) and a specificity of 100% whenever two or more promoters were found hypermethylated.KRASmutations showed a sensitivity of 77% (33 of 43, CI 95% 62 to 88%) and a specificity of 100%. Both molecular analyses added useful information to cytology by increasing the number of informative cases. When genetic and epigenetic analyses were combined sensitivity was 84% (36 of 43 CI 95% 69 to 93%) maintaining a 100% specificity.

Conclusions

Analysis of hypermethylation status of a panel of genes andKRASmutation detection offer a similar diagnostic yield in the evaluation of pancreatic masses. The combined molecular analysis increases the number of informative cases without diminishing specificity.
Balloon remodeling for aneurysm coil embolization with the coaxial lumen Scepter C balloon catheter: initial experience at a high volume center
Authors: Spiotta Alejandro M , Miranpuri Amrendra , Hawk Harris , Chaudry M Imran , Turk Aquilla S , Turner Raymond D
Published: November 2012

Introduction

The use of balloon remodeling allows for the treatment of aneurysms that were previously considered to be poor candidates for coil embolization. The Scepter C (Microvention, Tustin, California, USA) is a novel temporary occlusion balloon system with a dual coaxial lumen catheter. The design accommodates a more steerable 0.014 inch guidewire with improved control for delivery to the target lesion. We describe our initial experience with the use of this device for balloon remodeling to assist during aneurysm coil embolization.

Methods

All aneurysms that were treated with balloon remodeling employing the Scepter C balloon at a single institution (Medical University of South Carolina) from the time it was available in October 2011 to July 2012 were evaluated. Patient demographics, aneurysm characteristics, procedural success, and adverse events were assessed.

Results

52 aneurysms were treated in 48 patients (45 women, three men) with a mean age of 59.3±11 years (mean±SD). Mean aneurysm height was 5.9±3 mm, width 4.4±2 mm with a 3.1±2 mm broad neck. A variety of aneurysms were treated. The most commonly utilized size was the 4 mm×10 mm (n=33) balloon. A Raymond 1 (complete occlusion) was achieved in the majority (n=44; 84.6%) of aneurysms, Raymond 2 (residual neck) in five, and Raymond 3 (residual aneurysm) in five. There was one complication (1.9%) attributed directly to balloon use.

Conclusions

Our initial experience with the dual coaxial lumen Scepter C occlusion balloon catheter demonstrates its feasibility for use in balloon remodeling for aneurysm coil embolization. A variety of aneurysms at different locations were treated with satisfactory initial angiographic results and adverse event rates.
Effect of temperament and prolonged transportation on endocrine and functional variables in young beef bulls
Authors: Fazio E. , Medica P. , Cravana C. , Cavaleri S. , Ferlazzo A.
Published: November 2012

The purpose of this study was to evaluate the effect of prolonged transportation on adrenocorticotropic hormone (ACTH), cortisol, total and free triiodothyronine (T3, fT3) and thyroxine (T4, fT4) concentrations, and functional variables (heart rate (HR), respiratory rate (RR) and rectal temperature (RT)) in calm and temperamental Limousin young beef bulls. Exit velocity measurement was used to classify bulls' temperament as calm (group I: consisted of eight slowest bulls) and temperamental (group II: consisted of five fastest bulls). Calm subjects showed an increase of ACTH (P<0.05) and T4 (P<0.01) concentrations after transportation compared with before transportation values. Temperamental subjects showed higher ACTH (P<0.01) concentrations before transportation, and lower T4 (P<0.05) and fT4 (P<0.001) concentrations after transportation than calm subjects. Related to functional variables, temperamental young beef bulls showed a decrease of RT (P<0.05) after transportation compared with before values, higher RT (P<0.001) before transportation, and higher HR (P<0.001) and RR (P<0.01) after transportation than calm subjects. Data obtained suggest that longer periods of transportation could minimise the magnitude and duration of the endocrine and functional responses to stress of young beef bulls; such responses probably decrease or disappear during transport, in accordance with animal temperament.
Efficacy of in‐feed medication with chlortetracycline in a farrow‐to‐finish herd against a clinical outbreak of respiratory disease in fattening pigs
Authors: Del Pozo Sacristán R. , Rodríguez A. L. , Sierens A. , Vranckx K. , Boyen F. , Dereu A. , Haesebrouck F. , Maes D. G. D.
Published: November 2012

The efficacy of chlortetracycline (CTC) in‐feed medication to treat pigs with clinical respiratory disease was investigated in a farrow‐to‐finish pig herd infected with Mycoplasma hyopneumoniae, and with clinical respiratory disease in growing pigs. In total, 533 pigs were included. The animals were vaccinated against M hyopneumoniae and porcine circovirus type 2 at weaning. At onset of clinical respiratory disease, they were randomly allocated to one of the following treatment groups: chlortetracycline 1 (CTC1) (two consecutive weeks, 500 ppm), chlortetracycline 2 (CTC2) (two non‐consecutive weeks, with a non‐medicated week interval in between, 500 ppm) or tylosin (T) (three consecutive weeks, 100 ppm). Performance (daily weight gain, feed conversion ratio), pneumonia lesions at slaughter and clinical parameters (respiratory disease score) were assessed. Only numeric differences in favour of the CTC2 group were obtained for the performance and the clinical parameters. The prevalence of pneumonia lesions was 20.5, 13.1 and 23.0 per cent (P<0.05) for the CTC1, CTC2 and T groups, respectively. The study demonstrated that CTC, when administered at onset of clinical respiratory disease via the feed at a dose of 500 ppm during two alternative weeks, was able to decrease the prevalence of pneumonia lesions, and numerically reduce performance losses and clinical signs.
Steroid diffusion into the navicular bursa occurs in horses affected by palmar foot pain
Authors: Manfredi J. M. , Boyce M. , Malone E. D. , Anderson C. , Anderson L. B. , Trumble T. N.
Published: November 2012

Palmar foot pain is frequently treated by steroid injections into the distal interphalangeal joint (DIPJ) in the anticipation that the steroid will diffuse to the navicular bursa and palmar foot structures. The object of this study was to determine if triamcinolone acetonide (TA) would in fact be able to locally diffuse from the DIPJ into the navicular bursa in horses affected by palmar foot pain. Both forelimb DIPJs (nine horses) were injected with 10 mg of TA. Navicular bursa fluid samples, both forelimb and one hind limb (systemic control), were analysed for TA with high‐performance liquid chromatography/tandem mass spectrometry (HPLC‐MS/MS) six hours later. Foot radiographs were graded (0–4) on severity of changes. Forelimb navicular bursa TA concentrations (mean±sd log10, 3.20±0.56) were significantly higher than systemic control concentrations (mean±sd log10, 1.89±0.3) (P<0.0001). Horses with a radiographic grade of >2 were four times as likely to have TA log10 concentrations less than 3.2 (158.49 ng/ml). TA locally diffused from the DIPJ into the navicular bursa in horses affected by palmar foot pain; TA concentrations decreased as radiographic severity increased.
Summer emigration and resource acquisition within a shared nursery lake by sockeye salmon (Oncorhynchus nerka) from historically discrete rearing environments
Authors: Simmons Ryan K. , Quinn Thomas P. , Seeb Lisa W. , Schindler Daniel E. , Hilborn Ray
Published: November 2012

Many fish species disperse broadly during juvenile life history stages. While this may enable persistence in variable environments, it may also produce novel competitive interactions in recipient habitats that contain conspecifics from other populations. Here we used genetics techniques to study the stock-specific movement and performance of juvenile sockeye salmon (Oncorhynchus nerka) between July and August of 2008 in an ecosystem characterized by extensive juvenile migration and environmental change: the Chignik Lake system, Alaska. Genetic composition of juvenile sockeye salmon in the lower nursery lake based on 45 single nucleotide polymorphism markers indicated that 2008 was characterized by earlier timing and larger magnitude of emigrations from the upper lake, where rearing conditions have become increasingly unstable in recent decades. However, the larger size of emigrants did not confer a clear advantage in foraging based on comparisons of growth and body condition with juveniles native to the lower lake. These results highlight how shifting environmental conditions may exert pressures on evolved behavior patterns and increase interactions between sympatric populations, a theme of increasing importance where ecological uncertainty is high.
A Voronoi tessellation based approach to generate hypothetical forest landscapes
Authors: Passolt Gregor , Fix Miranda J. , Tóth Sándor F.
Published: November 2012

Optimization models used for forest planning can be computationally complex and the demand for real forest data to test them far exceeds the supply. As a result, hypothetical forest landscapes are often used, although their capacity to match the characteristics of real forests is limited and they offer little control over important landscape metrics such as average adjacency. Using four landscape metrics that are believed to be relevant to the computational efficiency of forest harvest scheduling models, we describe a new method for generating hypothetical landscapes of prespecified characterization. The new approach produces landscapes based on Voronoi tessellation, created from points chosen by a combination of random point processes. Through a series of multiple regressions, the proposed algorithm determines appropriate control parameters to ensure that the output landscape will match target characteristics within a given statistical tolerance and with a predefined probability. The new method can produce landscapes with a wide range of specifications, covering the characteristics of real forests and extending into extreme cases unlikely to be encountered in reality. At the same time, the method provides greater flexibility and control over the generated landscapes than previous methods.
Metallogeny of the Marco zone, Corvet Est, disseminated gold deposit, James Bay, Quebec, Canada
Authors: Aucoin Martin , Beaudoin Georges , Creaser Robert A. , Archer Paul
Published: November 2012

The Corvet Est gold deposit is hosted by Archean rocks of the Superior Province in the James Bay region, northern Quebec, Canada. The Marco zone is hosted by amphibolite-grade, strongly foliated volcanic rocks and consists of disseminated gold, with an apparent thickness ranging from 1.8 to 39.5 m and gold grades up to 23 g·t–1 over 1 m, that is continuous along strike for ∼1.3 km. The lithotectonic sequence comprises footwall basaltic andesite amphibolite overlain by a lenticular unit of metadacite and then by hanging-wall basaltic andesite amphibolite, all intruded by quartz–feldspar porphyry dikes. Dacite, basaltic andesite amphibolite, and quartz–feldspar porphyry show a calc-alkaline to transitional affinity and plot in the plate margin arc basalt field, with typical volcanic arc trace element patterns. Mineralization consists of pyrite, arsenopyrite, pyrrhotite, chalcopyrite, and gold, disseminated in deformed dacite, in andesite amphibolite, and in quartz–feldspar porphyry dikes. Dacite and andesite display weak alteration characterized by silicification. Native gold forms inclusions in metamorphic quartz, garnet, feldspar, arsenopyrite, and pyrite or free grains interstitial to quartz, feldspar, pyrite, chalcopyrite, and arsenopyrite. Free gold in late quartz veins cut the sericitized metamorphic fabric. Inclusion and interstitial native gold within minerals annealed during metamorphism shows that gold mineralization is pre- to syn-metamorphic, with some gold remobilized in later veins. Rhenium–osmium dating of arsenopyrite yields an isochron age of 2663 ± 13 Ma for mineralization and a weighted average model age of 2632 ± 7 Ma for arsenopyrite formed during peak metamorphism. The ∼2663 Ma arsenopyrite has a low initial 187Os/188Os of 0.19 ± 0.10, suggesting a juvenile crust or a mantle Os source. The sulfur isotope composition of Marco zone pyrite and arsenopyrite shows that sulfur could have been leached from its volcanic host rocks or from reduction of Archean seawater. The Corvet Est deposit is interpreted to be an orogenic gold deposit (2663 Ma) deformed and recrystallized during amphibolite-grade metamorphism (2632 Ma).
Facies architecture in depositional systems resulting from the interaction of acidic springs, alkaline springs, and acidic lakes: case study of Lake Roto-a-Tamaheke, Rotorua, New Zealand
Authors: Jones Brian , Renaut Robin W.
Published: November 2012

The facies architecture in hot spring systems tends to become more varied and complicated as the degrees of freedom in the system increase. Discharge aprons fed by waters from a single vent will, for example, be characterized by predictable downslope facies changes that reflect downslope changes in water chemistry and temperature. The facies architecture, however, becomes exponentially more intricate when more factors start to impact the system. This phenomenon is readily apparent in the geothermal area around Lake Roto-a-Tamaheke (located in the Whakarewarewa Thermal Village, Rotorua, New Zealand) where the facies architecture developed in response to the interactions between acid lake, acid hot spring, and alkaline hot spring depositional regimes, with additional extraneous sediment being brought into the area by volcanic ash clouds, wind-blown pollen, and surface run-off from the surrounding drainage basin. Much of the complexity in the facies architecture of this system stems from the temporal variance in the lake level and the variable life cycles of the acid and alkaline hot springs. Fluctuations in lake level controlled the extent of lacustrine deposits, and flooding commonly quenched spring activity. During some periods various minerals precipitated around the acidic springs, whereas during other periods silica precipitated around the hot alkaline springs that are preferentially located along faults that transect the area. The interaction of all of these variables produces depositional regimes with largely unpredictable and highly variable facies architectures. As such, they contrast sharply with the more organized spring systems that develop when one type of water flows from a single vent.
KILLING FORMS ON THE FIVE-DIMENSIONAL EINSTEIN–SASAKI Y(p, q) SPACES
Authors: VISINESCU MIHAI
Published: November 2012

We present the complete set of Killing–Yano tensors on the five-dimensional Einstein–Sasaki Y(p, q) spaces. Two new Killing–Yano tensors are identified, associated with the complex volume form of the Calabi–Yau metric cone. The corresponding hidden symmetries are not anomalous and the geodesic equations are superintegrable.
SHRIMPS: OCCURRENCE, SCALING AND RELEVANCE
Authors: STOOP RUEDI , MARTIGNOLI STEFAN , BENNER PHILIPP , STOOP RALPH L. , UWATE YOKO
Published: November 2012

Shrimps are islands of periodicity within a chaotic sea in phase and parameter spaces of dimensions larger than one. Islands of different periodicities have recently been shown to be connected by spirals that emanate from a joint focal point, paving ways to wander around in parameter space without ever crossing the chaotic sea. We discuss the shrimp building and scaling principles as well as the influence of individual system properties. While the emergence of shrimps has abundantly been demonstrated for artificial systems, we discuss here in detail evidence of rich hierarchies of shrimps in experimental systems. We finally pinpoint the importance of shrimps in the field of bioinformatics.
COMPARATIVE STUDY OF VARIATIONAL CHAOS INDICATORS AND ODEs' NUMERICAL INTEGRATORS
Authors: DARRIBA L. A. , MAFFIONE N. P. , CINCOTTA P. M. , GIORDANO C. M.
Published: November 2012

The reader can find in the literature a lot of different techniques to study the dynamics of a given system and also, many suitable numerical integrators to compute them. Notwithstanding the recent work of [Maffione et al., 2011b] for mappings, a detailed comparison among the widespread indicators of chaos in a general system is still lacking. Such a comparison could lead to select the most efficient algorithms given a certain dynamical problem. Furthermore, in order to choose the appropriate numerical integrators to compute them, more comparative studies among numerical integrators are also needed.

This work deals with both problems. We first extend the work of [Maffione et al., 2011b] for mappings to the 2D [Hénon & Heiles, 1964] potential, and compare several variational indicators of chaos: the Lyapunov Indicator (LI); the Mean Exponential Growth Factor of Nearby Orbits (MEGNO); the Smaller Alignment Index (SALI) and its generalized version, the Generalized Alignment Index (GALI); the Fast Lyapunov Indicator (FLI) and its variant, the Orthogonal Fast Lyapunov Indicator (OFLI); the Spectral Distance (D) and the Dynamical Spectra of Stretching Numbers (SSNs). We also include in the record the Relative Lyapunov Indicator (RLI), which is not a variational indicator as the others. Then, we test a numerical technique to integrate Ordinary Differential Equations (ODEs) based on the Taylor method implemented by [Jorba & Zou, 2005] (called taylor), and we compare its performance with other two well-known efficient integrators: the [Prince & Dormand, 1981] implementation of a Runge–Kutta of order 7–8 (DOPRI8) and a Bulirsch–Stöer implementation. These tests are run under two very different systems from the complexity of their equations point of view: a triaxial galactic potential model and a perturbed 3D quartic oscillator.

We first show that a combination of the FLI/OFLI, the MEGNO and the GALI 2N succeeds in describing in detail most of the dynamical characteristics of a general Hamiltonian system. In the second part, we show that the precision of taylor is better than that of the other integrators tested, but it is not well suited to integrate systems of equations which include the variational ones, like in the computing of almost all the preceeding indicators of chaos. The result which induces us to draw this conclusion is that the computing times spent by taylor are far greater than the times consumed by the DOPRI8 and the Bulirsch–Stöer integrators in such cases. On the other hand, the package is very efficient when we only need to integrate the equations of motion (both in precision and speed), for instance to study the chaotic diffusion. We also notice that taylor attains a greater precision on the coordinates than either the DOPRI8 or the Bulirsch–Stöer.
CHARACTERIZATION OF CHAOTIC ATTRACTORS INSIDE BAND-MERGING SCENARIO IN A ZAD-CONTROLLED BUCK CONVERTER
Authors: TABORDA JOHN ALEXANDER , ANGULO FABIOLA , OLIVAR GERARD
Published: November 2012

Zero Average Dynamics (ZAD) control strategy has been developed, applied and widely analyzed in the last decade. Numerous and interesting phenomena have been studied in systems controlled by ZAD strategy. In particular, the ZAD-controlled buck converter has been a source of nonlinear and nonsmooth phenomena, such as period-doubling, merging bands, period-doubling bands, torus destruction, fractal basins of attraction or codimension-2 bifurcations. In this paper, we report a new bifurcation scenario found inside band-merging scenario of ZAD-controlled buck converter. We use a novel qualitative framework named Dynamic Linkcounter (DLC) approach to characterize chaotic attractors between consecutive crisis bifurcations. This approach complements the results that can be obtained with Bandcounter approaches. Self-similar substructures denoted as Complex Dynamic Links (CDLs) are distinguished in multiband chaotic attractors. Geometrical changes in multiband chaotic attractors are detected when the control parameter of ZAD strategy is varied between two consecutive crisis bifurcations. Linkcount subtracting staircases are defined inside band-merging scenario.
NONLINEAR DYNAMICS AND THE SYNTHESIS OF ZEBRA FINCH SONG
Authors: PERL YONATAN SANZ , ARNEODO EZEQUIEL M. , AMADOR ANA , MINDLIN GABRIEL B.
Published: November 2012

Behavior emerges as the interaction between a nervous system, a peripheral biomechanical device and the environment. In birdsong production, this observation is particularly important: songbirds are an adequate animal model to unveil how brain structures reconfigure themselves during learning of a complex behavior as song. Therefore, it is important to understand which features of behavior are controlled by independent tuning of neurophysiological parameters, and which are constrained by the biomechanics of the peripheral vocal organ. In this work, we show that many of the acoustic features in the Zebra finch song are in fact conditioned by the biomechanics involved.
PINNING IMPULSIVE SYNCHRONIZATION OF COMPLEX DYNAMICAL NETWORKS
Authors: MAHDAVI NARIMAN , MENHAJ MOHAMMAD B. , KURTHS JÜRGEN , LU JIANQUAN , AFSHAR AHMAD
Published: November 2012

In this paper, the problem of pinning impulsive synchronization for complex dynamical networks with directed or undirected but a strongly connected topology is investigated. To remedy this problem, we propose an efficient algorithm to find certain suitable nodes to be controlled via pinning and these selected nodes, in general, could be different at distinct impulsive time instants. The proposed algorithm guarantees the efficiency of the designed pinning impulsive strategy for the global exponential synchronization of state-coupled dynamical networks under an easily-verified condition. In other words, impulsive controllers and an efficient algorithm are designed to control a small fraction of the nodes, which successfully controls the whole dynamical network. Furthermore, we also estimate the upper bound of the number of pinning nodes, which is shown to be closely related to the impulsive intervals. The relationship implies that the required number of pinning nodes, which should be controlled for the successful control of the whole dynamical network, can be greatly reduced by reducing the impulses interval. Finally, simulations of scale-free and small-world networks are given to illustrate the effectiveness of the theoretical results.
ADVECTION OF PASSIVE TRACERS IN THE ATMOSPHERE: BATCHELOR SCALING
Authors: HASZPRA TÍMEA , KISS PÉTER , TÉL TAMÁS , JÁNOSI IMRE M.
Published: November 2012

Extensive numerical experiments are performed on tracer dispersion in global reanalysis wind fields. Particle trajectories are computed both along an isobaric (500 hPa) and an isentropic (315 K) surface in a time interval of one year. Besides mean quantities such as advection of the center of mass and growth of tracer clouds, special attention is paid to the evaluation of particle pair separation dynamics. The characteristic behavior for intermediate time scales is Batchelor's dispersion along both surfaces, where the zonal extent of the tracer cloud increases linearly in time. The long-time evolution after 70–80 days exhibits a slower, diffusive dispersion (Taylor regime), in agreement with expectations. Richardson–Obukhov scaling (superdiffusion with an exponent of 3/2) could not be identified in the numerical tests. The results confirm the classical prediction by Batchelor that the initial pair-separation determines subsequent time evolution of tracers. The quantitative dependence on the initial distance differs however from the prediction of the theory.
FUNDAMENTALS OF A CLASSICAL CHAOS-BASED CRYPTOSYSTEM WITH SOME QUANTUM CRYPTOGRAPHY FEATURES
Authors: VIDAL G. , BAPTISTA M. S. , MANCINI H.
Published: November 2012

We present the fundamentals of a cryptographic method based on a hyperchaotic system and a protocol which inherits some properties of the quantum cryptography that can be straightforwardly applied on the existing communication systems of nonoptical communication channels. It is an appropriate tool to provide security on software applications for VoIP, as in Skype, dedicated to voice communication through Internet. This would enable that an information packet be sent through Internet preventing attacks with strategies similar to that employed if this same packet is transferred in an optical channel under a quantum cryptographic scheme. This method relies on fundamental properties possessed by chaotic signals and coupled chaotic systems. Some of these properties have never been explored in secure communications.
FRACTIONAL DYNAMICS IN FINANCIAL INDICES
Authors: TENREIRO MACHADO J. , DUARTE FERNANDO B. , DUARTE GONÇALO M.
Published: November 2012

The goal of this study is the analysis of the dynamical properties of financial data series from 32 worldwide stock market indices during the period 2000–2009 at a daily time horizon. Stock market indices are examples of complex interacting systems for which a huge amount of data exists. The methods and algorithms that have been explored for the description of physical phenomena become an effective background in the analysis of economical data. In this perspective are applied the classical concepts of signal analysis, Fourier transform and methods of fractional calculus. The results reveal classification patterns typical of fractional dynamical systems.
FOUR LIMIT CYCLES FROM PERTURBING QUADRATIC INTEGRABLE SYSTEMS BY QUADRATIC POLYNOMIALS
Authors: YU PEI , HAN MAOAN
Published: November 2012

In this paper, we present four limit cycles in quadratic near-integrable polynomial systems. It is shown that when a quadratic integrable system has two centers and is perturbed by quadratic polynomials, it can generate at least four limit cycles with (3,1)-distribution. This result provides a positive answer to an open question in this research area.
GENERALIZED ARITHMETIC CODING USING DISCRETE CHAOTIC MAPS
Authors: LIN QIUZHEN , WONG KWOK-WO , CHEN JIANYONG
Published: November 2012

Making use of the Lebesgue measure preserving property of the piecewise linear chaotic map, a discrete piecewise linear chaotic map is employed to perform the generalized arithmetic coding, which is an optimal entropy coding algorithm adopted by international standards. After a number of message symbols have been encoded by the reverse interval mapping, an enlargement on the encoding interval is performed and some codeword bits are exported accordingly. Based on the enlarged encoding interval, the subsequent symbols are encoded with the modified chaotic maps, the lower and upper bounds of which are determined by the final encoding interval of the symbols already encoded. In the decoding process, the message symbols are recovered by iterating the corresponding chaotic map from an appropriate initial value. The encoding interval enlargement is tracked by performing reverse interval mapping on the decoded symbols. More codeword bits are shifted into the register to form the initial value for decoding the subsequent symbols. Simulation results verify that the compression performance of our scheme is very close to the entropy bound and is comparable to traditional finite-precision arithmetic coding. In addition, cryptographic capability can be integrated into our scheme to make it a joint compression and encryption scheme. Its security is enhanced when compared with the existing schemes based on traditional arithmetic coding.
CYCLIC-FOLD BIFURCATION AND BOUNDARY CRISIS IN DYNAMIC WALKING OF BIPED ROBOTS
Authors: GRITLI HASSENE , BELGHITH SAFYA , KHRAIEF NAHLA
Published: November 2012

The aim of this paper is to show that the onset/destruction of bipedal chaos in the dynamic walking of a passive compass-gait biped robot and a semi-passive torso-driven biped robot walking down a slope can occur via a transition mechanism known as boundary crisis. It is known that such biped robots exhibit a scenario of period-doubling bifurcations route to chaos as one of their geometrical or inertial parameters changes. In this paper, we show that a cyclic-fold bifurcation is the key of the occurrence of a double boundary crisis. We demonstrate through bifurcation diagrams how the same period-three unstable periodic orbit generated from the cyclic-fold bifurcation causes the sudden birth/death of the bipedal chaos in the dynamic walking of the two biped robots. We stress that a double boundary crisis is responsible for the fall of each biped robot while walking down an inclined surface and as some bifurcation parameter varies. Stability of the cyclic-fold bifurcation under small perturbations is also discussed.
PARRONDO'S GAME MODEL TO FIND NUMERICALLY STABLE ATTRACTORS OF A TUMOR GROWTH MODEL
Authors: DANCA MARIUS-F. , LAI DEJIAN
Published: November 2012

In this paper, we present a simple and accessible way to enhance the stable behaviors of a chaotic dynamical system which models a cancer growth, as presented in [Itik & Banks, 2010]. The algorithm presented in [Danca et al., 2012], approximates numerically any attractor of a system belonging to a defined class of dynamical systems, by alternating the control parameter in relatively short periods of time. When switching the control parameter within a set of values corresponding to some chaotic behaviors, the result may be a stable evolution or, reversely a chaotic behavior may be obtained by switching the parameter within a set of values corresponding to stable evolutions. This apparently surprising phenomenon is, in fact, a generalization of the known Parrondo's paradox.
HAWKING RADIATION AS A MECHANISM FOR INFLATION
Authors: MODAK SUJOY KUMAR , SINGLETON DOUGLAS
Published: November 2012

The Friedman–Robertson–Walker (FRW) spacetime exhibits particle creation similar to Hawking radiation of a black hole. In this essay we show that this FRW Hawking radiation leads to an effective negative pressure fluid which can drive an inflationary period of exponential expansion in the early universe. Since the Hawking temperature of the FRW spacetime decreases as the universe expands this mechanism naturally turns off and the inflationary stage transitions to a power law expansion associated with an ordinary radiation-dominated universe.
EFFECT OF MgO ON STRUCTURE AND DIELECTRIC PROPERTIES OF CaO–Al2O3–B2O3–SiO2 GLASSES
Authors: DU ZHAO , ZHANG XUEHONG , YUE YUNLONG , WU HAITAO
Published: November 2012

The effect of MgO on structure and dielectric properties of aluminoborosilicate glasses was investigated. FTIR data indicated that glass network was mainly built by tetrahedral [ SiO4 ], [ BO4 ], [ AlO4 ] and trigonal [ BO3 ]. A small amount of AlO5 or AlO6 units also existed. The glass system was characterized with lower dielectric constant (4.17 ~ 4.6) and dielectric loss (12.3 × 10-4 ~ 14.77 × 10-4) at 1 MHz. With the increase of MgO content, the quantity of AlO5 or AlO6 units decreased. The variation of density showed a decreasing tendency. The dielectric constant and loss were all found to decrease.
GROWTH OF In2O3 ON In METAL AND ON InSb BY THE ELECTRON IRRADIATION
Authors: HAMAIDA K. , BOUSLAMA M. , GHAFFOUR M. , BESAHRAOUI F. , CHELAHI-CHIKR Z. , OUERDANE A. , ABDELLAOUI A. , GENDRY M.
Published: November 2012

Recently, the development of indium oxide such as In2O3 on the III–V semiconductors shows successful technological applications as in the gas sensor field, the emission devices, the biotechnology, etc. The indium oxide In2O3 attracted considerable research due to many methods of its synthesis. In our study, we were interested in developing the indium oxide In2O3 on the In metal and InSb surfaces by electron beam stimulated oxidation. The formation of In2O3 on InSb was advantaged by a previous treatment due to the sputtering of the surface by the argon ions at low energy 300 eV with a current density 2 μA/cm2 followed by heating in UHV at 300°C. Our results were monitored by the analysis techniques including the Auger electron spectroscopy (AES) and the electron energy loss spectroscopy (EELS) well suited to study the surface with respect to physical structure and chemical composition.
A SINGULAR STURM–LIOUVILLE EQUATION INVOLVING MEASURE DATA
Authors: WANG HUI
Published: November 2012

Let α > 0 and let μ be a bounded Radon measure on the interval (-1, 1). We are interested in the equation -(|x|2αu′)′ + u = μ on (-1, 1) with boundary condition u(-1) = u(1) = 0. We identify an appropriate concept of solution for this equation, and we establish some existence and uniqueness results. The cases 0 < α < 1 and α ≥ 1 must be considered separately. We also study the limiting behavior of two different approximation schemes: one is the elliptic regularization and the other is to approximate a measure μ by a sequence of L∞-functions.
ESTIMATES FOR THE SUMS OF EIGENVALUES OF THE FRACTIONAL LAPLACIAN ON A BOUNDED DOMAIN
Authors: YILDIRIM YOLCU SELMA , YOLCU TÜRKAY
Published: November 2012

The purpose of this paper is two-fold. Firstly, we state and prove a Berezin–Li–Yau-type estimate for the sums of eigenvalues of [Formula: see text], the fractional Laplacian operators restricted to a bounded domain Ω ⊂ ℝd for d ≥ 2 and α ∈ (0, 2]. Secondly, we provide an improvement to this estimate by using a pure analytical approach.
BIEQUIVARIANT MAPS ON SPHERES AND TOPOLOGICAL COMPLEXITY OF LENS SPACES
Authors: GONZÁLEZ JESÚS , VELASCO MAURILIO , WILSON W.STEPHEN
Published: November 2012

Weighted cup-length calculations in singular cohomology led Farber and Grant in 2008 to general lower bounds for the topological complexity of lens spaces. We replace singular cohomology by connective complex K-theory, and weighted cup-length arguments by considerations with biequivariant maps on spheres to improve on Farber–Grant's bounds by arbitrarily large amounts. Our calculations are based on the identification of key elements conjectured to generate the annihilator ideal of the toral bottom class in the ku-homology of the classifying space for a rank-2 abelian 2-group.
CONSTRAINED SCHRÖDINGER–POISSON SYSTEM WITH NON-CONSTANT INTERACTION
Authors: PISANI LORENZO , SICILIANO GAETANO
Published: November 2012

In this paper we are dealing with a Schrödinger–Maxwell system in a bounded domain of R3; the unknowns are the charged standing waves ψ = e-iωtu(x) in equilibrium with a purely electrostatic potential ϕ. The system is not autonomous, in the sense that the coupling depends on a function q = q(x). The non-homogeneous Neumann boundary condition on ϕ prescribes the flux of the electric field 𝔉 and gives rise to a necessary condition. On the other hand we consider the usual normalizing condition in L2for u. Under mild assumptions involving 𝔉 and the function q = q(x), we prove that this problem has a variational framework: its solutions can be characterized as constrained critical points. Then, by means of the Ljusternick–Schnirelmann theory, we get the existence of infinitely many solutions.
GROUP INVARIANCE AND POHOZAEV IDENTITY IN MOSER-TYPE INEQUALITIES
Authors: CASSANI DANIELE , RUF BERNHARD , TARSI CRISTINA
Published: November 2012

We study the so-called limiting Sobolev cases for embeddings of the spaces [Formula: see text], where Ω ⊂ ℝn is a bounded domain. Differently from J. Moser, we consider optimal embeddings into Zygmund spaces: we derive related Euler–Lagrange equations, and show that Moser's concentrating sequences are the solutions of these equations and thus realize the best constants of the corresponding embedding inequalities. Furthermore, we exhibit a group invariance, and show that Moser's sequence is generated by this group invariance and that the solutions of the limiting equation are unique up to this invariance. Finally, we derive a Pohozaev-type identity, and use it to prove that equations related to perturbed optimal embeddings do not have solutions.
NEW ESTIMATES FOR EVANS' VARIATIONAL APPROACH TO WEAK KAM THEORY
Authors: BERNARDI OLGA , CARDIN FRANCO , GUZZO MASSIMILIANO
Published: November 2012

We consider a recent approximate variational principle for weak KAM theory proposed by Evans. As in the case of classical integrability, for one-dimensional mechanical Hamiltonian systems all the computations can be carried out explicitly. In this setting, we illustrate the geometric content of the theory and prove new lower bounds for the estimates related to its dynamic interpretation. These estimates also extend to the case of n degrees of freedom.
SOME GEOMETRIC ANALYSIS ON GENERIC RICCI SOLITONS
Authors: MASTROLIA PAOLO , RIGOLI MARCO , RIMOLDI MICHELE
Published: November 2012

We study the geometry of complete generic Ricci solitons with the aid of some geometric-analytical tools extending techniques of the usual Riemannian setting.
A COMBINATORIAL DGA FOR LEGENDRIAN KNOTS FROM GENERATING FAMILIES
Authors: HENRY MICHAEL B. , RUTHERFORD DAN
Published: November 2012

For a Legendrian knot L ⊂ ℝ3, with a chosen Morse complex sequence (MCS), we construct a differential graded algebra (DGA) whose differential counts "chord paths" in the front projection of L. The definition of the DGA is motivated by considering Morse-theoretic data from generating families. In particular, when the MCS arises from a generating family F, we give a geometric interpretation of our chord paths as certain broken gradient trajectories which we call "gradient staircases". Given two equivalent MCS's we prove the corresponding linearized complexes of the DGA are isomorphic. If the MCS has a standard form, then we show that our DGA agrees with the Chekanov–Eliashberg DGA after changing coordinates by an augmentation.
CALIBRATIONS IN HYPER-KÄHLER GEOMETRY
Authors: GRANTCHAROV GUEO , VERBITSKY MISHA
Published: November 2012

We describe a family of calibrations arising naturally on a hyper-Kähler manifold M. These calibrations calibrate the holomorphic Lagrangian, holomorphic isotropic and holomorphic coisotropic subvarieties. When M is an HKT (hyper-Kähler with torsion) manifold with holonomy SL (n, ℍ), we construct another family of calibrations Φi, which calibrates holomorphic Lagrangian and holomorphic coisotropic subvarieties. The calibrations Φi are (generally speaking) not parallel with respect to any torsion-free connection on M.
NON-FACTORIAL NODAL COMPLETE INTERSECTION THREEFOLDS
Authors: CYNK SŁAWOMIR , RAMS SŁAWOMIR
Published: November 2012

We give a bound on the minimal number of singularities of a nodal projective complete intersection threefold which contains a smooth complete intersection surface that is not a Cartier divisor.
SPECTRAL DEFORMATIONS FOR QUASICYLINDRICAL DOMAINS
Authors: KALVIN VICTOR
Published: November 2012

We consider quasicylindrical domains that outside a bounded set coincide with long-range geometric perturbations of semi-cylinders. On the example of Dirichlet Laplacians we show that the method of spectral deformations, originating from the theory of Schrödinger operators, can be used to study spectral properties of elliptic problems in quasicylindrical domains.
THE NATURAL ORDER FOR THE E-ORDER-PRESERVING TRANSFORMATION SEMIGROUPS
Authors: Pei Huisheng , Deng Weina
Published: November 2012

Let (X, ≤) be a totally ordered finite set, [Formula: see text] be the full transformation semigroup on X and E be an arbitrary equivalence on X. We consider a subsemigroup of [Formula: see text] defined by [Formula: see text] and call it the E-order-preserving transformation semigroup on X. In this paper, we endow EOPX with the so-called natural order ≤ and discuss when two elements in EOPX are related under this order, then determine those elements of EOPX which are compatible with ≤. Also, the maximal (minimal) elements are described.
PSEUDO-DIFFERENTIAL OPERATORS INVOLVING HANKEL–CLIFFORD TRANSFORMATION
Authors: Prasad Akhilesh , Singh V. K. , Dixit M. M.
Published: November 2012

Pseudo-differential operator (p.d.o) associated with the symbol a(x, y) whose derivatives satisfy certain growth condition is defined and the Zemanian-type spaces Hμ(I) and S(I) are introduced. It is shown that the p.d.o is continuous linear map of the space Hμ(I) and S(I) into itself. An integral representation of p.d.o h1, μ, a is obtained. Using the Hankel convolution it is shown that p.d.o h1, μ, a satisfies a certain [Formula: see text]-norm inequality. Properties of Sobolev-type space [Formula: see text] are studied.
ON FILTERS OF IMPLICATIVE n.p.o. SEMIGROUPS
Authors: Rao M. Sambasiva , Shum K. P.
Published: November 2012

The concepts of implicative filters and derivations are introduced in implicative n.p.o. semigroups and studied their properties in connection with each other. The relation between order filters and implicative filters is also studied. The notion of implicative congruences is introduced in implicative n.p.o. semigroups. Finally, the equivalency between the existences of idempotent derivations and implicative filters is obtained.
ON THE DIMENSIONS OF CARTESIAN SYMMETRY CLASSES
Authors: Zamani Yousef , Shahryari Mohammad
Published: November 2012

The notion of Cartesian symmetry classes is introduced in [T. G. Lei, Notes on Cartesian symmetry classes and generalized trace functions, Linear Algebra Appl.292 (1999) 281–288]. In this paper, we discuss these classes and compute the dimensions of these classes in terms of the fixed point character of Sm. Also, we give a formula for the dimension of Cartesian symmetry class Vχ(G) in terms of the rank of an idempotent matrix M(χ). Some properties of generalized trace functions of a matrix are concluded.
Influence of organic content and degree of decomposition on the engineering properties of a peat soil in NE China
Authors: Nie Lei , Lv Yan , Li Miao
Published: November 2012

Peat soil comprises a large percentage of decayed vegetable matter from dead plants, which is decomposed in the presence of oxygen and micro-organisms. It is found in wetland bogs, moors, muskegs, pocosins, mires and peat swamp, and is characterized by high moisture content and high compressibility. It is also rich in humic acid and organic material. The physical and mechanical characteristics of peat soil are studied herein by conducting various laboratory tests based on the level of organic content of the peat. The results show that the greater the organic content in the peat soil, the higher the moisture content, porosity, compressibility and internal cohesion. Inversely, with higher organic content, the lower will be the density, consolidation coefficient and permeability. This is because the porous sponginess of organic material and the cohesive effect of the humic acid transform the structure of the peat.
The effect of groundwater overexploitation on land subsidence and sinkhole occurrences, western Iran
Authors: Khanlari Gholamreza , Heidari Mojtaba , Momeni Ali Akbar , Ahmadi Mohammad , Taleb Beydokhti Alireza
Published: November 2012

The main objective of this study was to evaluate the relationship between the declining groundwater level and land subsidence and sinkhole collapse in the Hamedan central plain, western Iran. In the last three decades, the increase in the use of groundwater for agricultural and industrial expansion accompanied by successive droughts has greatly lowered the groundwater level in the area. This has resulted in land subsidence and increased sinkhole occurrence. In this paper, both hydrogeological and geotechnical investigations were performed to identify a mechanism to explain the changes in the occurrence of these geological hazards. This study identifies three main triggering factors for the development of land subsidence and sinkhole formation. These factors include the presence of fine-grained materials (for land subsidence) and karstic limestone bedrock (for sinkhole formation), increase of effective stress, and generation of turbulent groundwater flow at the soil–bedrock interface. Risk of the occurrence of sinkholes affects planning decisions for most types of development in the study area. As a result of this study a sinkhole susceptibility map was generated indicating the location of hazardous regions.
The impact of petrographic characteristics on the engineering properties of ultrabasic rocks from northern and central Greece
Authors: Rigopoulos I. , Tsikouras B. , Pomonis P. , Hatzipanagiotou K.
Published: November 2012

This paper investigates the influence of petrographic characteristics on the engineering properties of ultrabasic rocks from the Pindos, Vourinos and Koziakas ophiolites. The studied lithologies include dunites, olivine-rich harzburgites, typical harzburgites and plagioclase-bearing lherzolites. Quantitative petrographic analysis indicates that the samples display various percentages of secondary minerals. The peridotites are tested to determine the following engineering parameters: water absorption, apparent density, total porosity, point load index, Schmidt hammer value, aggregate abrasion value and polished stone value. The relationships between the petrographic features and the engineering parameters are determined using regression analysis. The micropetrographic index
I
rep
and the ratios of secondary to primary (
S
e
/
P
) and soft to hard (
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o
/
H
) minerals provide significant information about the impact of ocean-floor metamorphism on the strength and durability of peridotites. The correlations indicate that the formation of secondary minerals results in mechanically weaker rocks. The polished stone value is the only engineering parameter that is positively affected by the presence of low contents of alteration products. The results also imply that Cr-spinel grains are a major determinant for the preservation of the microroughness of aggregate particles owing to their very hard nature and different mechanical behaviour compared with the surrounding silicate minerals.