bluuebunny/crossref_metadata_2025 huggingface dataset:
An EMG-Driven Biomechanical Model That Accounts for the Decrease in Moment Generation Capacity During a Dynamic Fatigued Condition
Authors: Rao Guillaume , Berton Eric , Amarantini David , Vigouroux Laurent , Buchanan Thomas S.
Published: April 2010

Although it is well known that fatigue can greatly reduce muscle forces, it is not generally included in biomechanical models. The aim of the present study was to develop an electromyographic-driven (EMG-driven) biomechanical model to estimate the contributions of flexor and extensor muscle groups to the net joint moment during a nonisokinetic functional movement (squat exercise) performed in nonfatigued and in fatigued conditions. A methodology that aims at balancing the decreased muscle moment production capacity following fatigue was developed. During an isometric fatigue session, a linear regression was created linking the decrease in force production capacity of the muscle (normalized force/EMG ratio) to the EMG mean frequency. Using the decrease in mean frequency estimated through wavelet transforms between dynamic squats performed before and after the fatigue session as input to the previous linear regression, a coefficient accounting for the presence of fatigue in the quadriceps group was computed. This coefficient was used to constrain the moment production capacity of the fatigued muscle group within an EMG-driven optimization model dedicated to estimate the contributions of the knee flexor and extensor muscle groups to the net joint moment. During squats, our results showed significant increases in the EMG amplitudes with fatigue (+23.27% in average) while the outputs of the EMG-driven model were similar. The modifications of the EMG amplitudes following fatigue were successfully taken into account while estimating the contributions of the flexor and extensor muscle groups to the net joint moment. These results demonstrated that the new procedure was able to estimate the decrease in moment production capacity of the fatigued muscle group.
Marker-Based Reconstruction of the Kinematics of a Chain of Segments: A New Method That Incorporates Joint Kinematic Constraints
Authors: Klous Miriam , Klous Sander
Published: April 2010

The aim of skin-marker-based motion analysis is to reconstruct the motion of a kinematical model from noisy measured motion of skin markers. Existing kinematic models for reconstruction of chains of segments can be divided into two categories: analytical methods that do not take joint constraints into account and numerical global optimization methods that do take joint constraints into account but require numerical optimization of a large number of degrees of freedom, especially when the number of segments increases. In this study, a new and largely analytical method for a chain of rigid bodies is presented, interconnected in spherical joints (chain-method). In this method, the number of generalized coordinates to be determined through numerical optimization is three, irrespective of the number of segments. This new method is compared with the analytical method of Veldpaus et al. [1988, “A Least-Squares Algorithm for the Equiform Transformation From Spatial Marker Co-Ordinates,” J. Biomech., 21, pp. 45–54] (Veldpaus-method, a method of the first category) and the numerical global optimization method of Lu and O’Connor [1999, “Bone Position Estimation From Skin-Marker Co-Ordinates Using Global Optimization With Joint Constraints,” J. Biomech., 32, pp. 129–134] (Lu-method, a method of the second category) regarding the effects of continuous noise simulating skin movement artifacts and regarding systematic errors in joint constraints. The study is based on simulated data to allow a comparison of the results of the different algorithms with true (noise- and error-free) marker locations. Results indicate a clear trend that accuracy for the chain-method is higher than the Veldpaus-method and similar to the Lu-method. Because large parts of the equations in the chain-method can be solved analytically, the speed of convergence in this method is substantially higher than in the Lu-method. With only three segments, the average number of required iterations with the chain-method is 3.0±0.2 times lower than with the Lu-method when skin movement artifacts are simulated by applying a continuous noise model. When simulating systematic errors in joint constraints, the number of iterations for the chain-method was almost a factor 5 lower than the number of iterations for the Lu-method. However, the Lu-method performs slightly better than the chain-method. The RMSD value between the reconstructed and actual marker positions is approximately 57% of the systematic error on the joint center positions for the Lu-method compared with 59% for the chain-method.
The Effect of Target Strain Error on Plantar Tissue Stress
Authors: Pai Shruti , Ledoux William R.
Published: April 2010

Accurate quantification of soft tissue properties, specifically the stress relaxation behavior of viscoelastic tissues such as plantar tissue, requires precise testing under physiologically relevant loading. However, limitations of testing equipment often result in target strain errors that can contribute to large stress errors and confound comparative results to an unknown extent. Previous investigations have modeled this artifact, but they have been unable to obtain empirical data to validate their models. Moreover, there are no studies that address this issue for plantar tissue. The purpose of this research was to directly measure the difference in peak force for a series of small target strain errors within the range of our typical stress relaxation experiments for the subcutaneous plantar soft tissue. Five plantar tissue specimens were tested to seven incremental target strain error levels of −0.9%, −0.6%, −0.3%, 0.0%, 0.3%, 0.6%, and 0.9%, so as to undershoot and overshoot the target displacement in 0.3% increments. The imposed strain errors were accurately attained using a special compensation feature of our materials testing software that can drive the actuator to within 0% (1−2 μm) of the target level for cyclic tests. Since stress relaxation tests are not cyclic, we emulated the ramp portion of our stress relaxation tests with 5 Hz triangle waves. The average total stress variation for all specimens was 25±5%, with the highest and lowest stresses corresponding to the largest and smallest strain errors of 0.9% and −0.9%, respectively. A strain overshoot of 0.3%, the target strain error observed in our typical stress relaxation experiments, corresponded to an average stress overshoot of 3±1%. Plantar tissue in compression is sensitive to small target strain errors that can result in stress errors that are several fold larger. The extent to which the overshoot may affect the peak stress will likely differ in magnitude for other soft tissues and loading modes.
A Mechanism to Explain Physiological Lubrication
Authors: James David F. , Fick Garret M. , Baines W. Douglas
Published: April 2010

A new mechanism of physiological lubrication is proposed to explain how low-viscosity synovial fluid prevents articular surfaces from contacting and wearing. The new mechanism is based on the hypothesis that the hyaluronic acid chains in synovial fluid bind to the cartilage surfaces through electrostatic charges, with the phospholipid layer on an articular surface supplying the necessary attractive charges. The stationary hyaluronic acid network causes a large hydrodynamic resistance to outward flow from the gap. To determine the effectiveness of the network in preventing contact, squeeze-film flow between two incompressible, permeable disks is analyzed when a constant load is suddenly applied, and the solvent—synovial fluid minus the hyaluronic acid—escapes through the network and through the permeable disks. The analysis yields the approximate time for the gap distance to decrease to asperity size. For realistic physiological parameters, the time for the surfaces to contact is a minimum of several minutes and likely much longer. The role of albumin in the synovial fluid is included because the large protein molecules are trapped by the small openings in the hyaluronic acid network, which increases the flow resistance of the network and thereby delays contact of the surfaces.
Scanning electron microscope studies on four species of Ulota from AustraliaThis paper is one of a selection of papers published as part of the special Schofield Gedenkschrift.
Authors: Ramsay Helen P.
Published: April 2010

Ulota species are difficult to separate to species level on leaf characters alone. In this study, scanning electron microscopy of habit and leaves, capsules, peristomes, and spores proved useful in separating four Australian species. Details of capsule and peristome, particularly distinctive features of the endostome, are shown.
Responses of boreal epiphytic bryophytes to different levels of partial canopy harvestThis paper is one of a selection of papers published as part of the special Schofield Gedenkschrift.
Authors: Caners Richard T. , Macdonald S. Ellen , Belland René J.
Published: April 2010

Epiphytic mosses and liverworts contribute substantially to the bryophyte diversity of circumpolar boreal forests but are susceptible to altered growing conditions after forest harvesting. Management practices that retain some trees after harvest may enhance epiphyte survival; however, the effectiveness of this emerging method needs to be assessed. We examined the survival, composition, and nearest neighbour relationships of epiphytic bryophytes on trembling aspen ( Populus tremuloides Michx.) across a range (10%–100%) of dispersed green-tree retention 5 years after harvest in boreal mixed-wood forest. Growth of the forest floor moss Hylocomium splendens (Hedw.) Schimp. in B.S.G. was used as an indicator of changes in moisture availability for epiphytes following harvesting. Epiphyte richness and abundance increased with canopy retention and were positively correlated with local abundance of coniferous trees. Positive associations among neighbouring species in intact forest demonstrated that interspecies relationships form naturally. However, there was a shift in species composition after harvesting and fewer interspecific associations with declining retention. These trends were accompanied by reduced Hylocomium splendens growth, which implies that moisture may be an important driver of epiphyte response. Although different levels of canopy retention were similarly capable of maintaining some epiphytes, the loss of species associated with intact forest will require consideration of alternative management practices for their conservation.
Introduction and recent range expansion in the mossPtychomitrium serratum(Ptychomitriaceae) in the Southern and Eastern United StatesThis paper is one of a selection of papers published as part of the special Schofield Gedenkschrift.
Authors: Miller Norton G. , Robinson Sean C.
Published: April 2010

The moss Ptychomitrium serratum (C. Müll. Hal. ex Schimp.) Besch., is native to Mexico and parts of western Texas and southern New Mexico, and it is a rare adventive in the area from East Texas and Louisiana to Missouri, Tennessee, South Carolina, and northward to locations near the coast in New York State and Massachusetts. In the adventive part of this calcicole’s range, all collections are from the past 50 years. Concrete, mortar, and rarely asphalt shingle are its only known substrata in this region, which contrasts sharply with its common occurrence on limestone in the native portion of its range. These observations indicate recent, perhaps on-going, immigration into the eastern United States and dispersal from established populations in this region. This monoicous moss commonly produces spores, which are its primary means of spread. Given the low density occurrences in the adventive portion of the range of P. serratum, dispersal may be generally northeastward from Mexico – Texas – New Mexico, following northeastward storm tracks in the southern and eastern United States. The apparently recent spread of this moss does not show obvious reliance on any direct human activity.
Schwetschkea (Brachytheciaceae) in Africa, and new to South AmericaThis paper is one of a selection of papers published as part of the special Schofield Gedenkschrift.
Authors: Buck William R. , Pôrto Kátia Cavalcanti
Published: April 2010

The African species of the moss genus Schwetschkea are revised based on morphological features of the gametophye and sporophyte. The genus is placed in the Brachytheciaceae. Three species are recognized, S. fabronioides (S. schweinfurthii, S. monbuttoviae, S. brotheri, syn. nov.), S. usambarica, and S. grateloupii. A key to these species is provided. Schwetschkea fabronioides is reported for the first time from South America from a Brazilian collection.
Resilience of bryophyte communities in regenerating matrix forests after logging in temperate rainforests of coastal British ColumbiaThis paper is one of a selection of papers published as part of the special Schofield Gedenkschrift.
Authors: Baldwin L. K. , Bradfield G. E.
Published: April 2010

The resilience (measured as changes in functional group representation and species composition) of bryophyte communities found in the younger-aged (“matrix”) forests surrounding old-growth remnants was examined in two different forest types, warmer, drier (Nimpkish) versus cooler, wetter (Sayward), on Vancouver Island, British Columbia. Bryophytes were sampled within 10 m × 2 m belt transects (species composition only) and using 10 cm × 30 cm microplots (composition and abundance) in two age classes of matrix forest, clearcuts (age 7–20 years), and second-growth (age 25–49 years) as well as in remnant old-growth forest stands (age >300 years). The cover of all bryophytes was diminished and more patchily distributed in younger-aged stands; however, the richness and frequency of bryophyte functional groups showed different responses in the two younger age class forests. Disturbance-associated species exhibited both higher richness and frequency in clearcut plots and higher richness in second-growth plots. In comparison, the richness of species associated with old-growth was largely unchanged in younger-aged forests compared with old-growth forests; however, the frequency of occurrence of species associated with old-growth was significantly reduced in younger-aged forests. The cooler, wetter forests exhibited greater resilience, as the difference in species composition between second-growth and old-growth stands was less than that between second-growth and old-growth stands in the warmer, drier forests. The greater difference in second-growth species composition in the warmer, drier forests was attributed mainly to the persistence of disturbance-associated species.
Phylogenetic and haplotype analyses of four segregates within Cladonia arbuscula s.l.This paper is one of a selection of papers published as part of the special Schofield Gedenkschrift.
Authors: Piercey-Normore Michele D. , Ahti Teuvo , Goward Trevor
Published: April 2010

Cladonia arbuscula (Wallr.) Flotow sensu lato is a widespread species complex traditionally divided among several subspecies on the basis of thallus morphology and secondary chemistry. Here we examine the evolutionary relationships of four of these segregates, C. arbuscula subsp. beringiana Ahti, C. arbuscula subsp. squarrosa (Wallr.) Burgaz, C. mitis Sandst., and an unnamed subspecies (referred to as C. arbuscula subsp. squarrosa PD– strain) in an attempt to link them to specific genotypes. The internal transcribed spacer regions of the nuclear ribosomal DNA (ITS rDNA) and the β-tubulin genes were sequenced for phylogenetic and haplotype analyses. In addition, the ITS2 RNA region was folded and changes were applied to the evolutionary hypothesis. We conclude that morphological differentiation within C. arbuscula s.l. is largely independent of variation in ITS rDNA and β-tubulin sequences, notwithstanding the distinct albeit incomplete clade formed by C. mitis. Compensatory base changes in the ITS2 RNA secondary structure could not support reproductive isolation. It is recommended that C. mitis be recognized at the subspecific rank as C. arbuscula subsp. mitis , and that subsp. squarrosa be included in subsp. beringiana . The apparent lack of correlation in C. arbuscula between genetic variability in the mycobiont and observed morphological variation in the thallus is intriguing, and requires explanation.
Distribution patterns of disjunct and endemic vascular plants in the interior wetbelt of northwest North AmericaThis paper is one of a selection of papers published as part of the special Schofield Gedenkschrift.
Authors: Björk Curtis R.
Published: April 2010

A region of contrastively wetter and milder climate occurs in inland northwest North America, separated from similar climates of the Pacific coast by 200–400 km. Researchers have long noted that numerous vascular plants divide their ranges between the interior wetbelt and coastal regions, although many such disjunctions have hitherto gone undocumented. Here I summarize all vascular plants shared between coastal and interior wetbelt regions, disjunct by at least 200 km. These disjunct taxa are assigned to north-coast and south-coast lists according to whether the coastal portions of the ranges occur primarily north or south of the southern limits of maximum continental glaciation. A list of interior wetbelt endemic taxa is also presented, focusing on those that occur at forested elevations. Presence/absence for coastal disjunct and endemic taxa were assigned to grid of 1° × 1° latitude–longitude cells. Using this grid, concentrations of disjunct and endemic taxa were detected, and total values per cell were tested in linear regression for a relationship to mean annual precipitation. In total, 116 coastal disjunct taxa were detected, 31 of them north-coastal and 85 south-coastal. Interior wetbelt endemic and subendemic taxa total 95, and of these, 46 were found primarily at forested elevations. North-coast taxa were found over a wide latitudinal range both north and south of the glacial limits, and their distribution had a weak positive relationship with annual precipitation. South-coast and endemic taxa were found mostly south of the glacial limits, and their distribution did not correlate to annual precipitation. The greatest concentrations of south coastal disjunct and endemic taxa occurred in the Clearwater region of north-central Idaho; a region noted by previous researchers to be a likely ice-age refugium for wet-climate dependent plants and animals. Inferences are made from these patterns, both for biogeographical understanding of the roles played by the interior wetbelt and some regions connecting to the coast, as well as for preservation of biodiversity and ecosystem continuity.
DISTRIBUTION OF MAGNETIC MONOPOLES WITHIN CUBES IN COMPACT QED
Authors: HÖLLWIESER ROMAN , FABER MANFRIED
Published: April 2010

Earlier investigations [Int. J. Mod. Phys. A19, 5017 (2004)] showed local minima in the monopole–antimonopole potential in U(1) gauge theory on the lattice. In this paper we localize monopoles of Monte Carlo configurations. A statistical analysis of localization measurements gives us the probability density which we compare with the potential found in Ref. 1. We find the monopoles mainly located either in the center of three-dimensional cubes or on the interface between two cubes. This agrees with the position of minima and maxima of the monopole–antimonopole potential.
SOME NONCONFORMAL ACCELERATING PERFECT FLUID PLATES OF EMBEDDING CLASS 1 USING SIMILARITY TRANSFORMATIONS
Authors: GUPTA Y. K. , PRATIBHA  , KUMAR SACHIN
Published: April 2010

In view of renewed interest in the space–time embedded in higher-dimensional flat space which are useful in extrinsic gravity, string and brane theory, a set of six explicit solutions to Einstein's field equations for nonconformally flat accelerating and shearing perfect fluid plates is obtained using similarity transformations method by considering a five-dimensional flat metric. All the solutions thus obtained are analyzed physically. All the solutions are new in their respective category as far as authors are aware.
PHENOMENOLOGICAL ANALYSIS OF pp AND $\bar{p}p$ ELASTIC SCATTERING DATA IN THE IMPACT PARAMETER SPACE
Authors: CAMPOS S. D.
Published: April 2010

We use an almost model-independent analytical parametrization for pp and [Formula: see text] elastic scattering data to analyze the eikonal, profile and inelastic overlap functions in the impact parameter space. Error propagation in the fit parameters allows estimations of uncertainty regions, improving the geometrical description of the hadron–hadron interaction. Several predictions are shown and, in particular, the prediction for pp inelastic overlap function at [Formula: see text] shows the saturation of the Froissart–Martin bound at LHC energies.
LOW POWER CONTINUOUS TIME COMMON MODE SENSING FOR COMMON MODE FEEDBACK CIRCUITS
Authors: PRAMOD M. , LAXMINIDHI T.
Published: April 2010

Continuous common mode feedback (CMFB) circuits having high input impedance and low distortion are proposed. The proposed circuits are characterized for 0.18 μm CMOS process with 1.8 V supply. Simulation results indicate that the proposed common mode detector consumes no standby power and CMFB circuit consumes 27–34% less power than previous high swing CMFB circuits.
HISTORY AND PROGRESS OF THE TOW THOMAS BI-QUADRATIC FILTER PART III: GENERATION USING NAM EXPANSION
Authors: SOLIMAN AHMED M.
Published: April 2010

A new generation method of the Tow-Thomas (TT) circuit based on the nodal admittance matrix (NAM) expansion is given. The family of TT circuits defined includes four different types of generated circuits. All the advantages of the classical TT circuit namely, independent control on the frequency, selectivity factor Q and gain, besides having very low passive sensitivities are maintained. Besides, each of the family members of the generated circuits use grounded passive elements and has very high input impedance. It is found that there are eight circuits in each type implying a total of 32 TT circuits using current conveyors (CCII) and inverting current conveyors (ICCII). 24 circuits are new and four of them have a floating property.
SYNTHESIS OF CONTROLLED SOURCES BY ADMITTANCE MATRIX EXPANSION
Authors: SOLIMAN AHMED M.
Published: April 2010

The admittance matrix expansion method based on using nullors and pathological mirror elements is used to provide a systematic synthesis method of controlled sources. Four new realizations of the current controlled voltage source (CCVS) using a single grounded resistor are given. Three new nodal admittance matrix expansions (NAM) for the voltage controlled voltage source (VCVS) are introduced in this paper. The voltage mirror current mirror pair is used as intrinsic element in the NAM expansion. Eight new realizations for the noninverting VCVS using two grounded resistors are given. Eight realizations for the inverting VCVS using two grounded resistors are also given. Two new NAM expansions for the current controlled current source (CCCS) are introduced in this paper. The voltage mirror current mirror pair is used as an intrinsic element in the NAM expansion. Eight realizations for the CCCS using two grounded resistors are given. The generation of the controlled sources using a single building block is also discussed and the adjoint relations between VCVS and CCCS are summarized.
AN ENERGY EFFICIENT HALF-STATIC CLOCK-GATING D-TYPE FLIP-FLOP
Authors: TAM WING-SHAN , WONG OI-YING , MOK KA-YAN , KOK CHI-WAH , WONG HEI
Published: April 2010

This paper presents a new design of half-static clock-gating D-type flip-flop (DFF). The proposed DFF consists of a dynamic master and a half-static slave built with a pass-transistor clock-gating circuitry. The new circuit has a very compact size, and can achieve low-power dissipation, especially in the case of low data activity. SPICE simulation results of the proposed DFF implemented with 0.18 μm CMOS technology are presented, which shows that the overall performance of the present design is better than most of the DFFs reported in literatures.
INFLUENCE OF TRAFFIC CORRELATION ON THE PERFORMANCE OF NETWORK-ON-CHIP DESIGNS
Authors: WANG FANG
Published: April 2010

Advance in semiconductor technologies enables seamless integration of hundreds of cores on a single silicon die, which requires high communication performance. To deal with the increasing communication complexity of System-on-Chip (SoC), Network-on-Chip (NoC) has been recently proposed as an alternative to the conventional point-to-point links and bus based communication fabrics. In practice, to facilitate NoC design evaluation and optimization, Poisson traffic or Bernoulli traffic models are generally assumed. However, actual measurements showed that real high speed network traffic always has strong correlations. The objective of this paper is to investigate the impact of traffic correlations on the performance of NoC design. Experimental results show that traffic correlation degrades the performance of NoC design and unrealistic traffic assumptions may yield unacceptable designs.
ON BANDWIDTH ESTIMATION OF MULTISTAGE AMPLIFIERS VIA AN EXTENDED MILLER APPROXIMATION
Authors: WEY TODD A.
Published: April 2010

A new bandwidth estimation method based on the application of Miller theorem to single and multistage common source amplifiers is presented. This new method provides more accurate bandwidth estimation and circuit design insight than the traditional Miller, Elmore and open circuit time constant approaches.
A NOVEL ALLOCATION METHODOLOGY FOR PARTIAL AND DYNAMIC BITSTREAM GENERATION FOR FPGA ARCHITECTURES
Authors: SIOZIOS KOSTAS , SOUDRIS DIMITRIOS , THANAILAKIS ANTONIOS
Published: April 2010

Partial re-configuration is the process of configuring a portion of a FPGA while the rest of the device is still running/operating. This paper proposes a novel allocation methodology for realizing applications with partial and dynamic features on FPGAs. The methodology was implemented as a manager that incorporates two stages: the first one modifies the configuration data of each partial bitstream by replacing the associated application's functionalities (or slices), its goal being to compact the slice distribution, while keeping the same functionality. The second one determines the appropriate spatial location over the FPGA device where the previously optimized configuration data should be placed. The proposed manager is device independent, since it derives partial configuration data that can program dynamically any island-style or hierarchical FPGA. For demonstration purposes, the proposed manager was implemented as part of an existing bitstream generator tool, named DAGGER (part from the MEANDER framework) targeting to Virtex-like architectures.
TAILORING THE BIFURCATION DIAGRAM OF NONLINEAR DYNAMICAL SYSTEMS: AN OPTIMIZATION BASED APPROACH
Authors: ALTIMARI PIETRO , MANCUSI ERASMO , DI BERNARDO MARIO , RUSSO LUCIA , CRESCITELLI SILVESTRO
Published: April 2010

Bifurcation tailoring is a method developed to design control laws modifying the bifurcation diagram of a nonlinear dynamical system to a desired one. In its original formulation, this method does not account for the possible presence of constraints on state and/or manipulated inputs. In this paper, a novel formulation of the bifurcation tailoring method overcoming this limitation is presented. In accordance with the proposed approach, a feedforward control law generating an optimal bifurcation diagram is computed by constrained minimization of an objective functional. Then, a feedback control system enforcing stability of the computed equilibrium branch is designed. In this context, bifurcation analysis is exploited to select feedback controller parameters ensuring desired output behavior and, at the same time, preventing the occurrence of multistability. The method is numerically validated on the problem of tailoring the bifurcation diagram of an exothermic chemical reactor.
A HYPERCHAOTIC CRISIS
Authors: HONG LING , ZHANG YINGWU , JIANG JUN
Published: April 2010

A crisis is investigated in high dimensional chaotic systems by means of generalized cell mapping digraph (GCMD) method. The crisis happens when a hyperchaotic attractor collides with a chaotic saddle in its fractal boundary, and is called a hyperchaotic boundary crisis. In such a case, the hyperchaotic attractor together with its basin of attraction is suddenly destroyed as a control parameter passes through a critical value, leaving behind a hyperchaotic saddle in the place of the original hyperchaotic attractor in phase space after the crisis, namely, the hyperchaotic attractor is converted into an incremental portion of the hyperchaotic saddle after the collision. This hyperchaotic saddle is an invariant and nonattracting hyperchaotic set. In the hyperchaotic boundary crisis, the chaotic saddle in the boundary has a complicated pattern and plays an extremely important role. We also investigate the formation and evolution of the chaotic saddle in the fractal boundary, particularly concentrating on its discontinuous bifurcations (metamorphoses). We demonstrate that the saddle in the boundary undergoes an abrupt enlargement in its size by a collision between two saddles in basin interior and boundary. Two examples of such a hyperchaotic crisis are given in Kawakami map.
INVARIANT TORUS IN 3D LOTKA–VOLTERRA SYSTEMS: THE NONDEGENERACY CONDITION
Authors: LUBOWIECKI PAWEŁ , ŻOŁADEK HENRYK
Published: April 2010

We complete the description of bifurcations for the deformation X0 + ε1x(x - x*)∂x + ε2xz∂x of the Lotka–Volterra vector field X0 = x(y + 2z +15u/2)∂x + y(x - 2z - 7u/2)∂y - z(x + y + 4u)∂z, u = x + y + z - 1, which was initiated in [Gołaszewski et al., 2008]. In particular, we prove existence and uniqueness of an invariant torus which appears in this family.
ON THE METAPOPULATION DYNAMICS OF AUTOCATALYSIS: EXTINCTION TRANSIENTS RELATED TO GHOSTS
Authors: SARDANYÉS JOSEP , FONTICH ERNEST
Published: April 2010

One of the theoretical approaches to study spatially-extended ecosystems is given by metapopulation models, which consider fragmented populations inhabiting discrete patches linked by migration. Most of the metapopulation models assume exponential growth of the local populations and few works have explored the role of cooperation in fragmented ecosystems. In this letter, we study the dynamics and the bifurcation scenarios of a minimal, two-patch metapopulation Turing-like model given by nonlinear differential equations with an autocatalytic reaction term together with diffusion. We also analyze the extinction transients of the metapopulations focusing on the effect of coupling two local populations undergoing delayed transition phenomena due to ghost saddle remnants. We find that increasing diffusion rates enhance the delaying capacity of the ghosts. We finally propose the saddle remnant as a new class of transient generator mechanism for ecological systems.
STRIPE PATTERNS IN A MODEL FOR BLOCK COPOLYMERS
Authors: PELETIER MARK A. , VENERONI MARCO
Published: April 2010

We consider a pattern-forming system in two space dimensions defined by an energy [Formula: see text]. The functional [Formula: see text] models strong phase separation in AB diblock copolymer melts, and patterns are represented by {0, 1}-valued functions; the values 0 and 1 correspond to the A and B phases. The parameter ε is the ratio between the intrinsic, material length-scale and the scale of the domain Ω. We show that in the limit ε → 0 any sequence uε of patterns with uniformly bounded energy [Formula: see text] becomes stripe-like: the pattern becomes locally one-dimensional and resembles a periodic stripe pattern of periodicity O(ε). In the limit the stripes become uniform in width and increasingly straight.

Our results are formulated as a convergence theorem, which states that the functional [Formula: see text] Gamma-converges to a limit functional [Formula: see text]. This limit functional is defined on fields of rank-one projections, which represent the local direction of the stripe pattern. The functional [Formula: see text] is only finite if the projection field solves a version of the Eikonal equation, and in that case it is the L2-norm of the divergence of the projection field, or equivalently the L2-norm of the curvature of the field.

At the level of patterns the converging objects are the jump measures |∇uε| combined with the projection fields corresponding to the tangents to the jump set. The central inequality from Peletier and Röger, Arch. Rational Mech. Anal.193 (2009) 475–537, provides the initial estimate and leads to weak measure-function pair convergence. We obtain strong convergence by exploiting the non-intersection property of the jump set.
ON THE SHARP SURFACE MODEL FOR COULOMB AND NUCLEAR INTERACTIONS BETWEEN TWO DEFORMED NUCLEI
Authors: ISMAIL M. , ELLITHI A. Y. , EL GEBALY H. , BOTROS M. M. , ADEL A.
Published: April 2010

The Coulomb and nuclear heavy ion (HI) potentials are derived for an interacting pair of deformed nuclei assuming sharp surface model for each nucleus. The orientation and separation dependences of the Coulomb and nuclear interactions are studied. It is assumed 238 U + 238 U as an example, and the effect of quadrupole term is investigated. For the nuclear potential part based on M3Y nucleon–nucleon interaction, the sharp surface model shows much difference compared with the more accurate frequently used multipole expansion method while the success of this model in calculating the Coulomb potential between this deformed pair of nuclei exists in the physically important surface region.
QUANTUM CONTROL IN NUCLEAR REACTION
Authors: WANG QUAN-FANG
Published: April 2010

A frontier field beyond atom and molecular control will be concentrated on the controlling of nuclei. Both theoretical design and laboratory experiments extremely need to be developed with the great progress of quantum physics and laser technology. This work is to focus on the computational approach to achieve the quantum control in nuclear reaction with a stable semi-discrete numerical paradigm in high dimensions. A reasonable physical model is established by multi-Klein–Gordon Schrödinger dynamics. Demonstrative experiments would provide the confident guidance to control quantum system at nuclei scale in real laboratory.
VOID ANALYSIS OF TARGET RESIDUES AT SPS ENERGY
Authors: SARKAR SAMABRATA , GHOSH DIPAK , DEB ARGHA , HALDAR PRABIR KUMAR , DAS RUPA
Published: April 2010

This paper presents new data on void analysis of target residues in ultrarelativistic nucleus–nucleus interaction. The study reveals a set of interesting observations. Void probability shows a scaling behavior at high energy (32 S –AgBr interactions at 200 A GeV) in both forward and backward hemisphere. Whereas such behavior is absent at low energy (16 O –AgBr interactions at 60 A GeV) in backward hemisphere.
MICROSCOPIC LOCAL OPTICAL POTENTIALS AND THE NUCLEON–NUCLEUS SCATTERING AT 65 MeV
Authors: HAIDER W. , SHARMA MANJARI
Published: April 2010

Microscopic local optical potentials from two sources were calculated by folding the numerical g-matrices over point proton and neutron RMF densities of target nuclei. The hard-core Hamada–Johnston and the soft-core Urbana v-14 local inter-nucleon potentials have been used to generate numerical g-matrices by solving Bethe–Goldstone integral equation. The calculated potentials have been used to analyze successfully both the proton and neutron differential elastic scattering and polarization data at 65 MeV over a wide mass region of targets: 12 C –208 Pb . Comparison of the present results with a phenomenological optical model analyzes is also presented. Mass number dependence of the mean square radii of the two microscopic potentials are in close agreement with each other as well as with empirical results.
MASS TERMS OF CP-VIOLATING WEINBERG THREE-HIGGS-DOUBLET MODEL AT A CHARGE-BREAKING VACUUM
Authors: ZARRINKAMAR S. , HASSANABADI H. , RAJABI A. A.
Published: April 2010

Weinberg three-Higgs-doublet model attracts interest in many aspects including the study of CP-violation as well as calculating the muon transverse polarization and neutron electric dipole moment. In the present work, we calculate the mass terms of CP-violating Weinberg 3HDM at a charge-breaking vacuum using an elaboratre basis.
Pathogenesis of Insulin Resistance in Skeletal Muscle
Authors: Abdul-Ghani Muhammad A. , DeFronzo Ralph A.
Published: April 2010

Insulin resistance in skeletal muscle is manifested by decreased insulin-stimulated glucose uptake and results from impaired insulin signaling and multiple post-receptor intracellular defects including impaired glucose transport, glucose phosphorylation, and reduced glucose oxidation and glycogen synthesis. Insulin resistance is a core defect in type 2 diabetes, it is also associated with obesity and the metabolic syndrome. Dysregulation of fatty acid metabolism plays a pivotal role in the pathogenesis of insulin resistance in skeletal muscle. Recent studies have reported a mitochondrial defect in oxidative phosphorylation in skeletal muscle in variety of insulin resistant states. In this review, we summarize the cellular and molecular defects that contribute to the development of insulin resistance in skeletal muscle.
Secure P2P Data Storage and Maintenance
Authors: Oualha Nouha , Önen Melek , Roudier Yves
Published: April 2010

P2P data storage requires strong reliability and security assurances. Existing data storage solutions have been designed for centralized as well as distributed settings; yet they do not address the security and cooperation issues raised by self-organization. P2P systems also introduce new needs regarding data availability due to the dynamicity of the infrastructure, which are unaddressed so far. This paper first discusses the approaches for tackling these problems. A solution is then introduced that relies on self-organizing security mechanisms in conjunction with a data rejuvenation scheme using erasure codes.
On the Complex and Real Hessian Polynomials
Authors: Martínez-Ojeda Emigdio , Ortiz-Rodríguez Adriana
Published: April 2010

We study some realization problems related to the Hessian polynomials. In particular, we solve the Hessian curve realization problem for degrees zero, one, two, and three and the Hessian polynomial realization problem for degrees zero, one, and two.
Effect of Individualized Exercise Training Combined with Diet Restriction on Inflammatory Markers and IGF-1/IGFBP-3 in Obese Children
Authors: Ben Ounis Omar , Elloumi Mohamed , Zouhal Hassane , Makni Emna , Denguezli Myriam , Amri Mohamed , Lac Gérard , Tabka Zouhair
Published: April 2010

Aims: The present study was designed to examine the possible changes in body composition, insulin-like growth factor 1 (IGF-1), insulin-like growth factor-binding protein-3 (IGFBP-3) and inflammatory markers of obese children in response to a 2-month program of exercise training combined with dietary restriction. Methods: Twenty-eight obese children (age 13.2 ± 0.7 years, body mass index 30.9 ± 1.3) were randomly assigned to a diet/training group or a control group and were tested two times: once before and once at the end of the experimental period. They performed a progressive cycle ergometer test at each visit. Substrate oxidation was evaluated by indirect calorimetry. Training was individualized at the point when fat oxidation was maximal (Lipoxmax). Results: Diet/training induced a significant decrease in body weight and body fat (after vs. before, p < 0.01). Plasma concentrations of IGF-1, IGFBP-3 and inflammatory markers were significantly decreased after the completion of the program. The diet/training program resulted in an increase in VO2maxACSM (24.6 ± 2.5 to 33.1 ± 3.1 ml/min/kg, p < 0.001) at the end of the intervention period. Conclu- sion: These data suggest that in the presence of weight loss, exercise training improves inflammatory markers and IGF-1 and IGFBP-3 levels in obese children.
Trauma as Triggering Factor for Development of Melanocytic Nevi
Authors: Navarini Alexander A. , Kolm Isabel , Calvo Ximena , Kamarashev Jivko , Kerl Katrin , Conrad Curdin , French Lars E. , Braun Ralph P.
Published: April 2010

The mechanisms for the development of acquired melanocytic nevi remain mostly unclear. Here we report a case of eruptive nevi that developed after localized superficial trauma, and review the currently known cellular and triggering factors for acquired melanocytic nevi. A 66-year-old woman presented a linear arrangement of pigmented macules on her left calf that developed after a bloodless skin erosion on the same spot, resulting from friction with the lining of a ski boot. Dermatopathology identified multiple junctional proliferations of single or small nest-forming melanocytes with bridging, pigment incontinence and moderate cellular atypia. The number of a person’s nevi correlates with age, race and genetics, but blistering diseases, scarring processes, light exposure and immunosuppression can contribute to nevocellular growth as well. Damaged keratinocytes and inflammatory cells can release growth factors inducing nevus cell proliferation, and immunosuppression could end cellular surveillance keeping preexisting nevus cell nests in check. We conclude that in predisposed patients, the trigger for eruptive nevi can be reduced to a simple localized minor trauma.
Serial Perfusion Study Depicts Pulmonary Vascular Growth in the Survivors of Non-Extracorporeal Membrane Oxygenation-Treated Congenital Diaphragmatic Hernia
Authors: Pal Kamalesh , Gupta D.K.
Published: April 2010

Background: Pulmonary growth in the survivors of congenital diaphragmatic hernia (CDH) still remains an intriguing issue. In the literature there are conflicting reports on pulmonary vascular growth in CDH. Objective: In a cohort of CDH patients treated without extracorporeal membrane oxygenation (ECMO), serial perfusion studies were conducted prospectively to follow the growth of pulmonary vasculature. Material and Methods: Survivors of CDH repair between January 2000 and January 2003 were studied prospectively. Patient demography, time of presentation, arterioalveolar oxygen gradient (A-aDO2), time to complete lung expansion, and respiratory symptoms were noted. Lung perfusion studies were done at 3 months, 9 months, and 6 years of follow-up. Results: 24 neonates completed the study. Mean presentation was 6.9 h, and preoperative A-aDO2 was 288.8. 16/24 were managed by conventional ventilation and 8/24 required high-frequency ventilation and nitric oxide therapy (none were treated with ECMO). Mean duration of preoperative stabilization was 26.5 h, time to full lung expansion was 2.8 days, and postoperative ventilation was 3.7 days. Mean perfusion (%) of ipsilateral lung was 33.7% at 3 months, 43.2% at 9 months, and 46.8% at 6 years. Perfusion of ipsilateral lung improved by 9.4% from 3 to 9 months (p < 0.001), 13.1% from 3 months to 6 years (p < 0.001), and 3.7% from 9 months to 6 years postoperatively (p < 0.001). Respiratory symptoms were seen in 45% (11/24) of survivors at 3 months, 14% (4/24) at 9 months, and 12.5% (3/24) at 6 years postoperatively. Conclusions: There was reduced perfusion of affected lung at 3 months which improved significantly at 9 months and at 6 years. Recovery of pulmonary vascular function correlated with amelioration of respiratory symptoms. The majority of survivors showing a significant vascular growth lead a symptom-free life.
LRRK2 G2019S in the North African Population: A Review
Authors: Benamer Hani T.S. , de Silva Rajith
Published: April 2010

Parkinson’s disease (PD) is a common neurodegenerative disorder, for which environmental and/or genetic factors are postulated as possible causes. Over the past decade there has been a substantial increase in the knowledge of the genetics of PD. Mutations in Leucine-rich repeat kinase 2 (LRRK2) are the most frequent genetic causes of PD, and the common G2019S mutation has been identified in various ethnic groups with variable frequency. The aim of this article is to review the literature relating to LRRK2 G2019S in the North African population, which is composed of two main ethnic groups – the Berbers and the Arabs. The frequency of LRRK2 G2019S is 30–41% in familial PD and 30–39% in apparently sporadic PD in North Africa. Within healthy controls, Moroccan Berbers appear to have the highest carrier frequency at 3.3%. The majority of the available studies do not draw a clear distinction between the two ethnic groups, despite the distinct possibility that their ancestral origins are different. Further research looking at the respective prevalences of LRRK2 G2019S in Berbers and Arabs, and in different Arab populations, seems justified.
Sinusoidal Heart Rate Patterns as a Manifestation of Massive Fetomaternal Hemorrhage in a Monochorionic-Diamniotic Twin Pregnancy: A Case Report
Authors: Watanabe Noriyoshi , Jwa Seung Chik , Ozawa Nobuaki , Sago Haruhiko
Published: April 2010

Objective: A case of fetomaternal hemorrhage (FMH) in monochorionic twins is reported. Method: Case report. Result: The patient felt a decrease in fetal movements at 32 gestational weeks. Cardiotocography showed sinusoidal heart rate patterns in both fetuses. The fetal hemoglobin level in maternal blood was 6.6% (normal 0.0–1.0%). Since the patient was diagnosed with massive FMH, cesarean section was performed and both babies delivered to receive neonatal treatment. Severe anemia was apparent in both infants, based on red blood cell count, hemoglobin concentration, and hematocrit of 86 × 10 and 85 × 104/mm3 (normal 376–456 × 104/mm3), 3.1 g/dl each (normal 10.9–13.5 g/dl), and 10.7 and 10.4% (normal 32.2–41.2%), respectively. Severe anemia may develop in both fetuses following massive FMH in monochorionic twins. As such, if abnormal circulation is detected in 1 monochorionic twin, the other fetus will also require special attention.
Cognitive Screening in Asia: Recognizing the Role of the Patient-Family Unit
Authors: Ng A. , Earnest A. , Yeo D. , Kandiah N.
Published: April 2010

Background/Aims: Cognitive screening programmes may improve awareness and help at-risk subjects receive earlier medical attention. Cognitive profiles of subjects who attend cognitive screening by personal choice (self-referred) compared to those where the referral was initiated by family members (family-referred) were compared. Methods: A cross-sectional survey of community subjects attending a cognitive screening initiative. Performance on the MMSE, Frontal Assessment Battery (FAB), Elderly Cognitive Assessment Questionnaire (ECAQ) and Even Briefer Assessment Scale for Depression was evaluated. Results: A total of 342 subjects with a mean age of 59.2 ± 9.0 years were screened. Overrepresentation of Chinese and Indian subjects and underrepresentation of Malay subjects was noted. The prevalence of cognitive impairment ranged from 7.0 to 9.6% depending on the screening instrument used. Of the 342 subjects, 267 were self-referred, while 75 subjects were family-referred. Family-referred subjects had lower MMSE (p < 0.001), lower ECAQ (p < 0.001) and lower FAB (p < 0.001) scores but were not more depressed compared to self-referred subjects (p = 0.904). Only the difference in ECAQ scores remained significant after adjustment for baseline differences in age and education. The prevalence of hypertension, diabetes mellitus and hypercholesterolaemia was not statistically different between the 2 groups. Conclusions: Family members play a crucial role in the diagnosis of cognitive impairment, especially in older subjects with fewer years of education.
Antenatal Sonography and MRI of Iniencephaly apertus and clausus
Authors: Gadodia A. , Gupta P. , Sharma R. , Kumar S. , Gupta G.
Published: April 2010

Iniencephaly is a lethal and an extremely rare neural tube defect. It is characterized by fixed retroflection of the head, cervical dysraphism and occipital bone defect. Associated anomalies of the nervous and other systems are frequently present. Most cases are diagnosed prenatally by ultrasound. We report prenatal ultrasonographic, fetal MRI and pathological findings of 2 cases of iniencephaly (one each of iniencephaly apertus and clausus).