bluuebunny/crossref_metadata_2025 huggingface dataset:
TWO-BODY RANDOM ENSEMBLE FOR NUCLEI
Authors: PAPENBROCK T. , WEIDENMÜLLER H. A.
Published: January 2007

The nuclear shell model exhibits dynamical and geometrical aspects. The former are determined by the two-body matrix elements of the residual interaction while the latter are due to the two-body operators that couple pairs of fermions to good quantum numbers of spin, isospin, and parity. We analyze the geometric aspects of the shell model and understand some of its generic properties regarding the generation of chaos in nuclear spectra and correlations between spectra with different quantum numbers. In particular, we address the preponderance of spin-0 ground states.
IMPORTANCE OF CORIOLIS INTERACTION IN DEFORMED PROTON EMITTERS
Authors: COSTA LOPES M. , FERREIRA L. S. , MAGLIONE E.
Published: January 2007

The decay by proton emission of deformed nuclei is discussed. The Coriolis coupling term is included in the non-adiabatic approach and calculations with non-spherical spin-orbit interactions are performed. Within this model, the half-lives of deformed drip-line odd-even nuclei are shown to be in good agreement with experimental data.
YRAST STATES IN 188,190Os NUCLEI
Authors: MOHAMMADI S. , DE ANGELIS G. , AXIOTIS M. , BAZZACCO D. , BIZZETI P. G. , BRANDOLINI F. , BRODA R. , BUCURESCU D. , FARNEA E. , GELLETLY W. , GADEA A. , IONESCU-BUJOR M. , IORDACHESCU A. , KRÖLL TH. , LONGDOWN S. , LUNARDI S. , MARGINEAN N. , MARTINEZ T. , MEDINA N. , PODOLYÁK Zs. , QUINTANA B. , REGAN P. H. , RUBIO B. , UR C. A. , VALIENTE DOBON J.-J. , WALKER P. M. , ZHANG Y. H.
Published: January 2007

Yrast states in neutron rich nuclei 188 Os and 190 Os have been populated using the deep-inelastic reaction 82 Se + 192 Os at 460 MeV beam bombarding energy. A thick 192 Os target (>50 mg/cm 2) with 0.2 mm Ta backing was used to stop all of the recoils in the target, minimising the broadening of the lines due to Doppler shift. High fold γ-γ coincidences were aquired with the 4π spectrometer GASP detector array. Three and two dimensional gamma-ray matrices were used to construct level schemes of the nuclei of interest up to an yrast state of 22.
STUDY OF β DECAY FROM EVEN-EVEN 124Ba TO ODD-ODD 124Cs IN THE INTERACTING BOSON-FERMION-FERMION MODEL
Authors: YOSHIDA N. , ZUFFI L. , BRANT S.
Published: January 2007

We study the β decay from an even-even nucleus 124 Ba to an odd-odd nucleus 124 Cs in the interacting boson-fermion-fermion model (IBFFM). The even-even nucleus is described by the proton-neutron interacting boson model (IBM2) while the odd-odd nucleus is by the proton-neutron interacting boson-fermion-fermion model (IBFFM2). The result shows that the model is applicable to β-decay as well as the energy levels and the electromagnetic properties.
GAMMA-RAY SPECTROSCOPY AT GANIL
Authors: DE FRANCE G.
Published: January 2007

Gamma-ray spectroscopy associated to the clear identification of the emitting nuclei is a key to understand in a coherent way the nuclear structure of the elements located far from stability. The coupling of very efficient gamma-ray arrays and spectrometers has pushed away the limits and opened up new possibilities in nuclear physics studies. These combinations give access to a comprehensive picture of both the reaction mechanism and the nuclear structure of a given nucleus. In this talk, the various possibilities offered at GANIL with such a coupling will be given.
ROTATIONAL DRIVEN NUCLEAR SHAPE PHASE TRANSITION OF THE YRAST STATES OF INDIVIDUAL NUCLEUS IN INTERACTING BOSON MODEL
Authors: ZHAO YUE , LIU YANG , MU LIANG-ZHU , LIU YU-XIN
Published: January 2007

With the intrinsic coherent state formalism and the angular momentum projection, we study the shape phase structure of the yrast states in the dynamical symmetries of the IBM. We found that the states in the U (5) symmetry can undergo a rotation driven vibrational to axially rotational shape phase transition if the interaction parameters take negative values smaller than the critical ones. It shows that the U (5) symmetry of the IBM1 is an appropriate approach to describe the rotation driven shape phase transition along the yrast line of individual nucleus as the interaction parameters are taken in a special region. The O (6) symmetric yrast states may involve a phase transition from γ-soft rotation to triaxial rotation as the angular momentum increases, if the interaction parameters are specially chosen. And the yrast states in SU (3) symmetry always appear in the axially prolate shape phase.
EVIDENCE FOR X(5) CRITICAL POINT SYMMETRY IN 128Ce
Authors: BALABANSKI D. L. , GLADNISHKI K. A. , LO BIANCO G. , SALTARELLI A. , ZAMFIR N. V. , McCUTCHAN E. A. , AI H. , CASTEN R. F. , HEINZ A. , MEYER D. A. , PLETTNER C. , QIAN J. , WERNER V. , WILLIAMS E. , AKKUS B. , AMON L. , CAKIRLI R. B. , ERDURAN M. N. , OKTEM Y. , ASHLEY S. F. , REGAN P. H. , RAINOVSKI G.
Published: January 2007

Lifetimes of excited states in 128 Ce were measured using the recoil distance Doppler-shift (RDDS) and the Doppler-shift attenuation (DSAM) methods. The experiments were performed at the Wright Nuclear Structure Laboratory of Yale University. Excited states of 128 Ce were populated in the 100 Mo (32 Si ,4 n ) reaction at 120 MeV and the nuclear γ decay was measured with an array of eight Clover detectors positioned at forward and backward angles. The deduced yrast transition strengths together with the energies of the levels within the ground-state (gs) band of 128 Ce are in agreement with the predicted values for the X (5) critical point symmetry. Thus, we suggest 128 Ce as a benchmark X (5) nucleus in the mass A ≈ 130 region.
ANALYSIS OF RAINFALL RECORDS IN INDIA: SELF-ORGANIZED CRITICALITY AND SCALING
Authors: SARKAR A. , BARAT P.
Published: January 2007

The time series data of the monthly rainfall records (for the time period 1871–2002) in All India and different regions of India are analyzed. It is found that the distributions of the rainfall intensity exhibit perfect power law behavior. The scaling analysis revealed two distinct scaling regions in the rainfall time series.
IMAGE COMPRESSION USING AFFINE FRACTAL INTERPOLATION ON RECTANGULAR LATTICES
Authors: DRAKOPOULOS V. , BOUBOULIS P. , THEODORIDIS S.
Published: January 2007

Two methods for representing discrete image data on rectangular lattices using fractal surfaces are proposed. They offer the advantage of a more general fractal modeling compared to previous one-dimensional fractal interpolation techniques resulting in higher compression ratios. Theory, implementation and analytical study of the proposed methods are also presented.
A FRACTAL APPROXIMATION TO PERIODICITY
Authors: NAVASCUÉS M. A.
Published: January 2007

Periodicity is recurrent in nature and society. The problem of the periodicity is faced here with the support of fractal methodology. Some analytical tools for the understanding of the one-dimensional projections of periodic phenomena are proposed. The reconstruction of an unknown periodic sampled variable is approached, assuming a deterministic self-affine nature in its small oscillations. Fractal trigonometric polynomials are defined by means of suitable iterated function systems. These objects are fractal perturbations of the classical circular functions. The coefficients of the system enable the control and modification of the properties of the originals. Additionally, Fourier parameters and approximants for sampled signals are computed and the density of the fractal trigonometric polynomials in the most common spaces of periodic functions is proved.
A NEW MEASURE OF LACUNARITY FOR GENERALIZED FRACTALS AND ITS IMPACT IN THE ELECTROMAGNETIC BEHAVIOR OF KOCH DIPOLE ANTENNAS
Authors: SENGUPTA KAUSHIK , VINOY K. J.
Published: January 2007

In recent years, fractal geometries have been explored in various branches of science and engineering. In antenna engineering several of these geometries have been studied due to their purported potential of realizing multi-resonant antennas. Although due to the complex nature of fractals most of these previous studies were experimental, there have been some analytical investigations on the performance of the antennas using them. One such analytical attempt was aimed at quantitatively relating fractal dimension with antenna characteristics within a single fractal set. It is however desirable to have all fractal geometries covered under one framework for antenna design and other similar applications. With this objective as the final goal, we strive in this paper to extend an earlier approach to more generalized situations, by incorporating the lacunarity of fractal geometries as a measure of its spatial distribution. Since the available measure of lacunarity was found to be inconsistent, in this paper we propose to use a new measure to quantize the fractal lacunarity. We also demonstrate the use of this new measure in uniquely explaining the behavior of dipole antennas made of generalized Koch curves and go on to show how fundamental lacunarity is in influencing electromagnetic behavior of fractal antennas. It is expected that this averaged measure of lacunarity may find applications in areas beyond antennas.
CERTAIN QUANTUM KEY DISTRIBUTION ACHIEVED BY USING BELL STATES
Authors: LI CHONG , WANG ZHEN , WU CHUNFENG , SONG HE-SHAN , ZHOU LING
Published: January 2007

A new protocol for quantum key distribution based on entanglement swapping is proposed. In this protocol, both certain key and random key can be generated without any loss of security.
LINEAR QUANTUM CODES OF MINIMUM DISTANCE THREE
Authors: LI RUIHU , LI XUELIANG , XU ZONGBEN
Published: January 2007

We give elementary recursive constructions of quaternary self-orthogonal codes with dual distance three for all n ≥ 5. Consequently, good linear quantum codes of minimum distance three for such length n are obtained. Almost all of these linear quantum codes are optimal or near optimal.
AN EFFICIENT PROTOCOL FOR SECURE AND DETERMINISTIC QUANTUM KEY EXPANSION
Authors: WANG XIANG-BIN
Published: January 2007

We present a protocol for secure quantum key expansion. Our protocol costs almost zero classical communication and less qubits than that in the standard protocols. Since the bit value of the expanded key is deterministic, this protocol can also be used for direct communication. Our protocol includes the authentication steps, therefore, we do not worry about the case that Alice and Bob are completely isolated.
M-BODY PURE STATE ENTANGLEMENT
Authors: PAN FENG , DRAAYER J. P.
Published: January 2007

The simple entanglement of N-body N-particle pure states is extended to the more general M-body or M-body N-particle states where N ≠ M. Some new features of the M-body N-particle pure states are discussed. An application of the measure to quantify quantum correlations in a Bose–Einstien condensate model is demonstrated.
IMPLEMENTATION OF QUANTUM LOGIC OPERATIONS AND CREATION OF ENTANGLEMENT BETWEEN TWO NUCLEAR SPIN QUBITS WITH CONSTANT INTERACTION
Authors: BERMAN G. P. , BROWN G. W. , HAWLEY M. E. , KAMENEV D. I. , TSIFRINOVICH V. I.
Published: January 2007

We describe how to implement quantum logic operations in a silicon-based quantum computer with phosphorus atoms serving as qubits. The information is stored in the states of nuclear spins and the conditional logic operations are implemented through the electron spins using nuclear–electron hyperfine and electron–electron exchange interactions. The electrons in our computer should stay coherent only during implementation of one Controlled-NOT gate. The exchange interaction is constant, and selective excitations are provided by a magnetic field gradient. The quantum logic operations are implemented by rectangular radio-frequency pulses. This architecture is scalable and does not require manufacturing nanoscale electronic gates. As shown in this paper, parameters of a quantum protocol can be derived analytically even for a computer with a large number of qubits using our perturbation approach. We present the protocol for initialization of the nuclear spins and the protocol for creation of entanglement. All analytical results are tested numerically using a two-qubit system.
ON THE AUTOMORPHISM GROUPS OF A FAMILY OF BINARY QUANTUM ERROR-CORRECTING CODES
Authors: LIU TAILIN , WEN FENGTONG , WEN QIAOYAN
Published: January 2007

Based on the classical binary simplex code [Formula: see text] and any fixed-point-free element f of [Formula: see text], Calderbank et al. constructed a binary quantum error-correcting code [Formula: see text]. They proved that [Formula: see text] has a normal subgroup H, which is a semidirect product group of the centralizer Z(f) of f in GLm(2) with [Formula: see text], and the index [Formula: see text] is the number of elements of Ff = {f, 1 - f, 1/f, 1 - 1/f, 1/(1 - f), f/(1 - f)} that are conjugate to f. In this paper, a theorem to describe the relationship between the quotient group [Formula: see text] and the set Ff is presented, and a way to find the elements of Ff that are conjugate to f is proposed. Then we prove that [Formula: see text] is isomorphic to S3 and H is a semidirect product group of [Formula: see text] with [Formula: see text] in the linear case. Finally, we generalize a result due to Calderbank et al.
CONTINUOUS-TIME QUANTUM WALKS ON ULTRAMETRIC SPACES
Authors: KONNO NORIO
Published: January 2007

We introduce a continuous-time quantum walk on an ultrametric space corresponding to the set of p-adic integers and compute its time-averaged probability distribution. It is shown that localization occurs for any location of the ultrametric space for the walk. This result presents a striking contrast to the classical random walk case. Moreover, we clarify a difference between the ultrametric space and other graphs, such as cycle graph, line, hypercube and complete graph, for the localization of the quantum case. Our quantum walk may be useful for a quantum search algorithm on a tree-like hierarchical structure.
ENTANGLEMENT IN A DIMERIZED ANTIFERROMAGNETIC HEISENBERG CHAIN
Authors: HAO XIANG , ZHU SHIQUN
Published: January 2007

The entanglement properties in an antiferromagnetic dimerized Heisenberg spin-1/2 chain are investigated. The entanglement gap, which is the difference between the ground-state energy and the minimal energy that any separable state can attain, is calculated to detect the entanglement. It is found that the entanglement gap can be increased by varying the alternation parameter. Through thermal energy, the witness of the entanglement can determine a characteristic temperature below which an entangled state can be obtained. The entanglement detected by the energy can provide a lower bound for that determined by the concurrence. If the alternation parameter is smaller than a critical value, there is always no inter-dimer entanglement in the chain.
SPECTROELECTROCHEMICAL RECOGNITION OF CHEMICAL DOPANTS IN THE INNER SPACE OF CARBON NANOSTRUCTURES
Authors: KALBÁČ MARTIN , KAVAN LADISLAV , ZUKALOVÁ MARKÉTA , DUNSCH LOTHAR
Published: January 2007

By in situ Raman spectroelectrochemistry the state of chemical dopants in the inner space of potassium vapor treated single-walled carbon nanotubes (SWCNT), double-walled carbon nanotubes (DWCNT) and C 60 fullerene peapods was followed. We show that the spectroelectrochemistry is a method of choice to locate the dopant within carbon nanostructures. The presence of potassium inside the carbon nanostructures was found to be associated with a characteristic response of the tangential (TG) mode of SWCNT to electrochemical doping after treatment of the sample with the water. Our study confirmed the presence of residual potassium in peapods even after treatment with water. On the other hand, potassium was not found in the interior of the water-treated DWCNT and SWCNT.
QUENCHING OF SURFACE PLASMON MODES IN COLLOIDAL SILVER NANOPARTICLES ON OZONIZATION
Authors: RAKSHIT R. K. , BHATTACHARYA SAYANTANI , BUDHANI R. C.
Published: January 2007

Oxidation characteristics of colloidal silver nanoparticles produced by pulsed laser ablation in pure and chemically treated water are studied as a function of the degree of ozonization. The bright yellow colloidal solution of silver characterized by a sharp surface plasmon mode at ~400 nm, becomes colorless in the initial stages of O 3 flow, and then acquires a brown hue with a broad plasmon peak centered at ~440 to ~450 nm on further ozonization. The solution again becomes colorless in a few days once the O 3 flow is stopped. We present a qualitative model for the reaction dynamics and analyze the optical absorption in the framework of an effective medium theory. The aqueous phase laser ablation chemistry described here provides a unique means to produce ionic silver for enhanced antimicrobial effects.
CONTROLLED ELECTRIC FIELD-ASSISTED JETTING FROM VISCOUS AND NANOSUSPENSION MEDIA DROPLETS
Authors: JAYASINGHE S. N.
Published: January 2007

This paper reports a study into forming a jet-on-demand to continuous microthreads by subjecting electric fields on high viscosity and low conducting media (concentrated nanosuspensions and dielectric mediums) droplets, placed on a conducting copper plate, which has a similar plate above at a distance of ~ 10 mm. The media used in this investigation has a viscosity ≫ 1000 mPa s and an electrical conductivity ≪ 10-6 Sm-1 and in the case of nanomaterial loading in suspension is 003E; 15 wt.%. The investigation illustrates both the ability to form jets in this configuration and the importance of the volume of media placed as a droplet which has a direct result on the formation of a jet subsequently fragmentating to droplets. At a droplet volume of < Q0, the resting droplet when under the influence of an applied electric field deforms forming a cone, much like those referred to as the "Taylor Cones". On increasing the volume of the droplet to Q0 and applying a voltage of ~ 4.6 kV across the plates, the apex of the cone was observed to pulsate. On further increasing the applied voltage, giving rise to an electric field strength of ~ 0.55 kV/mm, the pulsating apex stabilizes to evolve a stable jet which undergoes instabilities promoting the generation of droplets. Consequently, a fine jet-on-demand is obtained. On increasing the droplet volume to > Q0, forms jets on both plates. The study elucidates the importance of this jetting approach for forming droplet relics containing self-assembled nanoparticles to continuous microthreads from concentrated nanosuspensions and dielectric media for forming structures by deposition that are most useful and have widespread applications in materials science and engineering. Hence, the physical behavior of this droplet deformation — jetting — forming droplets under an imposed field, outlines the discussion presented in this paper.
PHOTON-ASSISTED TRANSPORT CHARACTERISTICS THROUGH QUANTUM DOT COUPLED TO SUPERCONDUCTING RESERVOIRS
Authors: ATALLAH A. S. , PHILLIPS A. H. , AMIN A. F. , SEMARY M. A.
Published: January 2007

The influence of time-varying fields on the transport through a mesoscopic device has been investigated. This mesoscopic device is modeled as a quantum dot coupled to superconducting reservoirs via quantum point contact. The effect of a magnetic field and the Andreev reflection process were taken into account. The conductance was deduced by using Landuaer–Buttiker equation. A numerical calculation has been performed that shows a resonant tunneling behavior. Such investigation is important for fabricating photoelectron mesoscopic devices.
NF-κB activation by depolarization of skeletal muscle cells depends on ryanodine and IP3 receptor-mediated calcium signals
Authors: Valdés Juan Antonio , Hidalgo Jorge , Galaz José Luis , Puentes Natalia , Silva Mónica , Jaimovich Enrique , Carrasco M. Angélica
Published: January 2007

Depolarization of skeletal muscle cells by either high external K+ or repetitive extracellular field potential pulses induces calcium release from internal stores. The two components of this release are mediated by either ryanodine receptors or inositol 1,4,5-trisphosphate (IP3) receptors and show differences in kinetics, amplitude, and subcellular localization. We have reported that the transcriptional regulators including ERKs, cAMP/Ca2+-response element binding protein, c- fos, c- jun, and egr-1 are activated by K+-induced depolarization and that their activation requires IP3-dependent calcium release. We presently describe the activation of the nuclear transcription factor NF-κB in response to depolarization by either high K+ (chronic) or electrical pulses (fluctuating). Calcium transients of relative short duration activate an NF-κB reporter gene to an intermediate level, whereas long-lasting calcium increases obtained by prolonged electrical stimulation protocols of various frequencies induce maximal activation of NF-κB. This activation is independent of extracellular calcium, whereas calcium release mediated by either ryanodine or IP3 receptors contribute in all conditions tested. NF-κB activation is mediated by IκBα degradation and p65 translocation to the nucleus. Partial blockade by N-acetyl-l-cysteine, a general antioxidant, suggests the participation of reactive oxygen species. Calcium-dependent signaling pathways such as those linked to calcineurin and PKC also contribute to NF-κB activation by depolarization, as assessed by blockade through pharmacological agents. These results suggest that NF-κB activation in skeletal muscle cells is linked to membrane depolarization and depends on the duration of elevated intracellular calcium. It can be regulated by sequential activation of calcium release mediated by the ryanodine and by IP3 receptors.
Src and focal adhesion kinase mediate mechanical strain-induced proliferation and ERK1/2 phosphorylation in human H441 pulmonary epithelial cells
Authors: Chaturvedi Lakshmi S. , Marsh Harold M. , Basson Marc D.
Published: January 2007

Pulmonary epithelial cells are exposed to repetitive deformation during physiological breathing and mechanical ventilation. Such deformation may influence pulmonary growth, development, and barotrauma. Although deformation stimulates proliferation and activates extracellular signal-regulated kinases (ERK1/2) in human pulmonary epithelial H441 cells, the upstream mechanosensors that induce ERK activation are poorly understood. We investigated whether c-Src or focal adhesion kinase (FAK) mediates cyclic mechanical strain-induced ERK1/2 activation and proliferation in human pulmonary epithelial (NCI-H441) cells. The H441 and A549 cells were grown on collagen I-precoated membranes and were subjected to an average 10% cyclic mechanical strain at 20 cycles/min. Cyclic strain activated Src within 2 min by increasing phosphorylation at Tyr418, followed by rapid phosphorylation of FAK at Tyr397 and Tyr576 and ERK1/2 at Thr202/Tyr204 ( n = 5, P < 0.05). Twenty-four (A549 cells) and 24–72 h (H441 cells) of cyclic mechanical strain increased cell numbers compared with static culture. Twenty-four hours of cyclic strain also increased H441 FAK, Src, and ERK phosphorylation without affecting total FAK, Src, or ERK protein. The mitogenic effect was blocked by Src (10 μmol/l PP2 or short interfering RNA targeted to Src) or MEK (50 μmol/l PD-98059) inhibition. PP2 also blocked strain-induced phosphorylation of FAK-Tyr576 and ERK-Thr202/Tyr204 but not FAK-Tyr397. Reducing FAK by FAK-targeted short interfering RNA blocked mechanical strain-induced mitogenicity and significantly attenuated strain-induced ERK activation but not strain-induced Src phosphorylation. Together, these results suggest that repetitive mechanical deformation induced by ventilation supports pulmonary epithelial proliferation by a pathway involving Src, FAK, and then ERK signaling.
Changes in regulation of sodium/calcium exchanger of avian ventricular heart cells during embryonic development
Authors: Shepherd Neal , Graham Victoria , Trevedi Bhavya , Creazzo Tony L.
Published: January 2007

It has been suggested that the sodium/calcium exchanger NCX1 may have a more important physiological role in embryonic and neonatal hearts than in adult hearts. However, in chick heart sarcolemmal vesicles, sodium-dependent calcium transport is reported to be small and, moreover, to be 3–12 times smaller in hearts at embryonic day (ED) 4–5 than at ED18, the opposite of what would be expected of a transporter that is more important in early development. To better assess the role of NCX1 in calcium regulation in the chick embryonic heart, we measured the activity of NCX1 in chick embryonic hearts as extracellular calcium-activated exchanger current ( INCX) under controlled ionic conditions. With intracellular calcium concentration ([Ca2+]i) = 47 nM, INCX density increased from 1.34 ± 0.28 pA/pF at ED2 to 3.22 ± 0.55 pA/pF at ED11 ( P = 0.006); however, with [Ca2+]i = 481 nM, the increase was small and statistically insignificant, from 4.54 ± 0.77 to 5.88 ± 0.73 pA/pF ( P = 0.20, membrane potential = 0 mV, extracellular calcium concentration = 2 mM). Plots of INCX density against [Ca2+]i were well fitted by the Michaelis-Menton equation and extrapolated to identical maximal currents for ED2 and ED11 cells (extracellular calcium concentration = 1, 2, or 4 mM). Thus the increase in INCX at low [Ca2+]i appeared to reflect a developmental change in allosteric regulation of the exchanger by intracellular calcium rather than an increase in the membrane density of NCX1. Supporting this conclusion, RT-PCR demonstrated little change in the amount of mRNA encoding NCX1 expression from ED2 through ED18.
Substantia nigra osmoregulation: taurine and ATP involvement
Authors: Morales Ingrid , Dopico Jose G. , Sabate Magdalena , Gonzalez-Hernandez Tomas , Rodriguez Manuel
Published: January 2007

An extracellular nonsynaptic taurine pool of glial origin was recently reported in the substantia nigra (SN). There is previous evidence showing taurine as an inhibitory neurotransmitter in the SN, but the physiological role of this nonsynaptic pool of taurine has not been explored. By using microdialysis methods, we studied the action of local osmolarity on the nonsynaptic taurine pool in the SN of the rat. Hypoosmolar pulses (285-80 mosM) administered in the SN by the microdialysis probe increased extrasynaptic taurine in a dose-dependent way, a response that was counteracted by compensating osmolarity with choline. The opposite effect (taurine decrease) was observed when osmolarity was increased. Under basal conditions, the blockade of either the AMPA-kainate glutamate receptors with 6-cyano-7-nitroquinoxaline-2,3-dionine disodium or the purinergic receptors with pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid modified the taurine concentration, suggesting that both receptors modulate the extrasynaptic pool of taurine. In addition, these drugs decreased the taurine response to hypoosmolar pulses, suggesting roles for glutamatergic and purinergic receptors in the taurine response to osmolarity. The participation of purinergic receptors was also supported by the fact that ATP (which, under basal conditions, increased the extrasynaptic taurine in a dose-dependent way) administered in doses saturating purinergic receptors also decreased the taurine response to hypoosmolarity. Taken together, present data suggest osmoregulation as a role of the nonsynaptic taurine pool of the SN, a function that also involves glutamate and ATP and that could influence the nigral cell vulnerability in Parkinson's disease.
Intraspinal Stimulation Caudal to Spinal Cord Transections in Rats. Testing the Propriospinal Hypothesis
Authors: Yakovenko Sergiy , Kowalczewski Jan , Prochazka Arthur
Published: January 2007

Many laboratories have reported the successful regeneration of neurons across damaged portions of the spinal cord. Associated improvements in hindlimb locomotor movements have been attributed to the formation of functional neuronal connections with the locomotor central pattern generator (CPG). However, regenerating axons generally extend no more than 10 mm caudal to the lesion sites, terminating about 20 mm short of the lumbar segments thought to contain the CPG. It has therefore tacitly been assumed that the locomotor improvements arose from activation of propriospinal neurons relaying excitation to the CPG. Here we report a test of this assumption, which we call the propriospinal hypothesis. Intraspinal microstimulation (ISMS) was used to activate the putative propriospinal relay neurons. Approximately 2–3 wk after complete spinal cord transection at T8–T9 in rats, an array of six Pt–Ir microwires was chronically implanted in the intermediate and ventral gray matter of T10–T12 segments. ISMS pulse trains with amplitudes of 0.8–0.9 times threshold for activating axial muscles were delivered during open-field locomotor tests (BBB). ISMS significantly increased BBB scores over control tests, but did not produce limb coordination and weight bearing sufficient for locomotion. These results support the main assumption of the propriospinal hypothesis: that neuronal activity elicited in thoracic spinal segments caudal to a complete spinal cord transection may propagate caudally and activate the locomotor CPG.
Characteristics and Mechanisms of Locomotion Induced by Intraspinal Microstimulation and Dorsal Root Stimulation in Spinal Cats
Authors: Barthélemy D. , Leblond H. , Rossignol S.
Published: January 2007

Intraspinal microstimulation (ISMS) through a single microelectrode can induce locomotion in cats spinalized at T131 wk before (untrained) or after 3–5 wk of treadmill training. Here we study the optimal parameters of ISMS and the characteristics of locomotion evoked. ISMS was applied in the dorsal region of segments L3–S1at different lateralities (midline to 2.5 mm) and after an intravenous injection of clonidine (noradrenergic agonist). Kinematics and electromyographic recordings were used to characterize locomotion. ISMS could induce a bilateral locomotor pattern similar to that obtained with perineal stimulation, and the characteristics of locomotion varied according to the spinal segment stimulated. Mechanisms by which ISMS could evoke locomotion were then investigated by stimulating, inactivating, or lesioning different spinal structures. Dorsal root stimulation (DRS), just like ISMS, could evoke a variety of ipsi- and bilateral nonlocomotor movements as well as locomotor responses. This suggests that sensory afferent pathways are involved in the production of locomotion by ISMS. Microinjections of yohimbine (noradrenergic antagonist) in L3and L4segments or a complete second spinal lesion at L3–L4abolished all locomotor activity evoked by ISMS applied at more caudal segments. Progressive dorsoventral spinal lesions at L3or L4and restricted ventral lesions at L4further suggest that the integrity of the ventral or ventrolateral funiculi as well as the L3–L4segments are critical for the induction of locomotion by ISMS at L5to S1or by DRS at these caudal segments.
Two Cases of Ampulla (Takotsubo-Shaped) Cardiomyopathy Associated with Hemophagocytic Lymphohistiocytosis
Authors: Takeoka Yasunobu , Nakamae Mika , Nakamae Hirohisa , Hagihara Kiyoyuki , Sakamoto Erina , Nakane Takahiko , Koh Hideo , Koh Ki-Ryang , Ohta Kensuke , Yamane Takahisa , Hino Masayuki
Published: January 2007

There have been many reports of patients with ampulla cardiomyopathy described as takotsubo-shaped cardiomyopathy in the cardiovascular field. This unique cardiomyopathy is characterized by transient apical ballooning and hypokinesis of the left ventricle. We describe 2 cases of ampulla cardiomyopathy associated with hemophagocytic lymphohistiocytosis (HLH). In both of the patients, ventricular dysfunction suddenly occurred during the active phase of HLH. In each case, the findings on ECG, echocardiogram and left ventriculogram were compatible with ampulla cardiomyopathy. To our knowledge, this communication is the first to report cases of ampulla cardiomyopathy associated with HLH. Our cases suggest that HLH hypercytokinemia may have a role in causing ampulla cardiomyopathy.
Development of Cerebral Infarction Shortly after Intracerebral Hemorrhage
Authors: Kim Chul H. , Kim Jong S.
Published: January 2007

Background and Purpose: Cerebral infarction (CI) occurring soon after intracerebral hemorrhage (ICH) has been rarely reported. The purpose of the present study was to characterize this condition and discuss the possible pathophysiology. Method: We retrospectively studied 6 patients who developed CI within 10 days after the onset of ICH. Results: The initial ICHs were located in the putamen (n = 3), thalamus (n = 2) and cerebellum (n = 1), and were considered to be caused by hypertension in all of the patients. They showed sudden worsening (n = 4) or change in neurologic symptoms (n = 2) within 10 days after the initial ICH. Follow-up imaging revealed corresponding lacunar (n = 2) and territorial (n = 4) infarcts. Possible factors related to the development of new CIs included mechanical compression of cerebral vessels (n = 2), dehydration (n = 4), hypotension (n = 2), infection (n = 2) and concomitant small-vessel pathology (n = 2). Conclusions: ICH may predispose certain patients to the development of infarcts through a combination of mechanisms, including mechanical compression of cerebral vessels, hemodynamic instability, inflammation and concomitant small-vessel pathology.
Carotid Ultrasound Criteria for Detecting Intracranial Carotid Stenosis
Authors: Lee Jiann-Der , Ryu Shan-Jin , Chang Yeu-Jhy , Hsu Kai-Cheng , Chen Yi-Chun , Huang Ying-Chih , Lee Meng , Hsiao Ming-Chang , Lee Tsong-Hai
Published: January 2007

Background/Aims: This study attempted to establish carotid ultrasound criteria for identifying stenosis of the intracranial internal carotid artery (ICA) and middle cerebral artery (MCA). Methods: Two hundred and fifty-five patients were enrolled. Ultrasound measurements for common carotid artery (CCA) and ICA were as follows: flow volume (FV), peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI) and resistance index (RI). The sensitivity and specificity of the ultrasound criteria for determining intracranial ICA or MCA ≧50% stenosis were calculated. Results: The criteria identified for detecting intracranial ICA ≧50% stenosis were ICA FV <159 ml/min, ICA PSV <33 cm/s and CCA PSV <42 cm/s. When ICA PSV <33 cm/s was combined with CCA PSV <42 cm/s, sensitivity increased to 82%, with 91% specificity. The criteria identified for detecting MCA ≧50% stenosis were CCA FV <285 ml/min, ICA FV <179 ml/min, ICA PSV <33 cm/s, >35% reduction in FV in the CCA, >40% reduction in FV in ICA, and >35% reduction in PSV in ICA. When these criteria were combined, sensitivity increased to 69%, with 85% specificity. Conclusion: This study demonstrated that ultrasound criteria are sensitive and specific for detecting intracranial ICA and MCA significant obstruction.
IREL – A Psychometric Instrument for Measuring Life Themes
Authors: Hammelstein Philipp , Berger Ruth , Buergy Martin , Fiedler Peter , Mundt Christoph
Published: January 2007

Background: Although biographical narratives and work involving the meaning of biographical episodes is a central focus in any psychotherapy, there remains a lack of psychometric instruments for measuring the autobiographical construction as such. We will be presenting a theoretical model of an autobiographical construction of life themes and the Interview of Retrospective Exploration of Life themes (IREL) will be used as the basis of a psychometric instrument. The IREL takes about 90–120 min. The interrater reliability and test-retest reliability will be examined. Methods: Two samples of 21 and 23 mentally healthy subjects were recruited. In addition to the IREL, the Beck Depression Inventory (BDI) and SCID were also used to control for psychopathological status and depressive mood. Results: According to our data, biographical events can be explored objectively and reliably using the IREL. Minor test-retest variability of the affective valence of life themes is not state-dependent. Conclusions: Setting aside limitations due to the small sample sizes, the results suggest that the proposed interview is an objective and reliable instrument for measuring central issues within the subjective biographical construction (life themes).
Discriminant Ability and Criterion Validity of the HoNOS in Italian Psychiatric Residential Facilities
Authors: Gigantesco A. , Picardi A. , de Girolamo G. , Morosini P.
Published: January 2007

Background: The Health of the Nation Outcomes Scales (HoNOS) was developed as an inclusive and comprehensive instrument to assess patient outcomes in 4 main domains: behaviour, cognitive and physical impairment, symptoms and social functioning/context. Concerns about the reliability and validity of the HoNOS have been raised. The aim of this study was to further investigate the discriminatory ability of the HoNOS; criterion validity was also examined. Sampling and Methods: A broad sample of patients with psychotic disorders, admitted to 265 Italian residential facilities, were rated by trained research assistants and local staff on the HoNOS, Global Assessment of Functioning, Life Skills Profile, and Physical Health Index. Discriminant function analysis was used to examine the ability of the HoNOS items to correctly classify patients with positive symptoms, substantial psychosocial impairment or physical disability. The HoNOS criterion validity was also examined. Results: On the whole, the pattern of correlations between the HoNOS and the other corresponding measures was consistent. However, the majority of the correlations were only moderate. In discriminant function analysis, the classification procedure correctly classified 55.7% of the patients. Conclusions: Although the HoNOS has many advantages in its brevity, it may lack sufficient discriminatory ability for certain patient groups. Further, it correlates only moderately with measures of disability and physical health status. These findings suggest that the HoNOS alone might be insufficient for routine evaluation and should probably be supplemented by additional measures.
Disability Evolution in Multiple Sclerosis: How to Deal with Missing Transition Times in the Markov Model?
Authors: Petiot V. , Quantin C. , Le Teuff G. , Chavance M. , Binquet C. , Abrahamowicz M. , Moreau T.
Published: January 2007

Markov modeling of disability progression in multiple sclerosis requires knowledge of all times of transitions from a given level of disability to the next level, but such data are often missing. We address methodological challenges due to partly missing transition times. To estimate the effects of prognostic factors on the risk of transitions between three consecutive disability levels, two methods were used to deal with missing data. Listwise deletion limited the analysis to subjects with complete data. Multiple imputation of missing data revealed that data were missing at random (MAR mechanism) and imputed the missing transition times from the Weibull model. The results were then compared with the full data set with the actual times established through chart review. Multiple imputation estimates were systematically closer to those from the full data set than the listwise deletion estimates.
Saxatilin, a Snake Venom Disintegrin, Regulates Platelet Activation Associated with Human Vascular Endothelial Cell Migration and Invasion
Authors: Jang Yoon-Jung , Jeon Ok-Hee , Kim Doo-Sik
Published: January 2007

Background: Platelet activation results in platelet aggregation and the secretion of granules, which contain a variety of constituents including nonprotein molecules, adhesive proteins and hydrolases. The platelet-derived supernatant (PDS), which contains these granules, is known to trigger the activation of endothelium and chemotaxis of monocytes. Methods and Results: PDS derived from collagen-activated platelets stimulated human umbilical vein endothelial cell (HUVEC) migration and invasion, as measured through the use of a Boyden chamber. This collagen-induced PDS also triggered integrin αvβ3 upregulation in HUVECs. The inclusion of a neutralizing antibody to platelet-derived growth factor (PDGF)-B abolished HUVEC migration/invasion and integrin αvβ3 upregulation, showing that PDGF-AB mediates the proangiogenic effects of collagen-activated PDS. Saxatilin, a snake venom disintegrin known to interrupt platelet aggregation by antagonizing integrin αIIbβ3, inhibited the collagen-induced platelet activation and abolished the angiogenic properties of PDS. Saxatilin also inhibited the collagen-induced phosphorylation of Syk, a key mediator of inside-out signaling in platelet activation. Conclusion: Saxatilin inhibits platelet activation, platelet PDGF-AB release as well as subsequent endothelial cell migration and invasion.
Intraseasonal and Seasonally Persisting Patterns of Indian Monsoon Rainfall
Authors: Krishnamurthy V. , Shukla J.
Published: January 2007

The space–time structure of the active and break periods of the Indian monsoon has been studied using 70-yr-long high-resolution gridded daily rainfall data over India. The analysis of lagged composites of rainfall anomalies based on an objective categorization of active and break phases shows that the active (break) cycle, with an average life of 16 days, starts with positive (negative) rainfall anomalies over the Western Ghats and eastern part of central India and intensifies and expands to a region covering central India and parts of north India during the peak phase, while negative (positive) anomalies cover the sub-Himalayan region and southeast India. During the final stage of the active (break) period, the positive (negative) rainfall anomalies move toward the foothills of the Himalayas while peninsular India is covered with opposite sign anomalies. The number of days on which lows and depressions are present in the region during active and break periods is consistent with the rainfall analysis. The number of depressions during the active phase is about 7 times that during the break phase.

Using multichannel singular spectrum analysis of the daily rainfall anomalies, the seasonal monsoon rainfall is found to consist of two dominant intraseasonal oscillations with periods of 45 and 20 days and three seasonally persisting components. The 45- and 20-day oscillations are manifestations of the active and break periods but contribute very little to the seasonal mean rainfall. The seasonally persisting components with anomalies of the same sign, and covering all of India, have a very high interannual correlation with the total seasonal mean rainfall. These results support a conceptual model of the interannual variability of the monsoon rainfall consisting of seasonal mean components and a statistical average of the intraseasonal variations. The success in the prediction of seasonal mean rainfall depends on the relative strengths of the seasonally persisting components and intraseasonal oscillations.
The Frequency of Extreme Rain Events in Satellite Rain-Rate Estimates and an Atmospheric General Circulation Model
Authors: Wilcox Eric M. , Donner Leo J.
Published: January 2007

The frequency distributions of surface rain rate are evaluated in the Tropical Rainfall Measuring Mission (TRMM) and Special Sensor Microwave/Imager (SSM/I) satellite observations and the NOAA/GFDL global atmosphere model version 2 (AM2). Instantaneous satellite rain-rate observations averaged over the 2.5° latitude × 2° longitude model grid are shown to be representative of the half-hour rain rate from single time steps simulated by the model. Rain-rate events exceeding 10 mm h−1 are observed by satellites in most regions, with 1 mm h−1 events occurring more than two orders of magnitude more frequently than 10 mm h−1 events. A model simulation using the relaxed Arakawa–Schubert (RAS) formulation of cumulus convection exhibits a strong bias toward many more light rain events compared to the observations and far too few heavy rain events. A simulation using an alternative convection scheme, which includes an explicit representation of mesoscale circulations and an alternative formulation of the closure, exhibits, among other differences, an order of magnitude more tropical rain events above the 5 mm h−1 rate compared to the RAS simulation. This simulation demonstrates that global atmospheric models can be made to produce heavy rain events, in some cases even exceeding the observed frequency of such events. Additional simulations reveal that the frequency distribution of the surface rain rate in the GCM is shaped by a variety of components within the convection parameterization, including the closure, convective triggers, the spectrum of convective and mesoscale clouds, and other parameters whose physical basis is currently only understood to a limited extent. Furthermore, these components interact nonlinearly such that the sensitivity of the rain-rate distribution to the formulation of one component may depend on the formulation of the others. Two simulations using different convection parameterizations are performed using perturbed sea surface temperatures as a surrogate for greenhouse gas–forced climate warming. Changes in the frequency of rain events greater than 2 mm h−1 associated with changing the convection scheme in the model are greater than the changes in the frequency of heavy rain events associated with a 2-K warming using either model. Thus, uncertainty persists with respect to simulating intensity distributions for precipitation and projecting their future changes. Improving the representation of the frequency distribution of rain rates will rely on refinements in the formulation of cumulus closure and the other components of convection schemes, and greater certainty in predictions of future changes in both total rainfall and in rain-rate distributions will require additional refinements in those parameterizations that determine the cloud and water vapor feedbacks.
Trends in Block-Seasonal Extreme Rainfall over the Iberian Peninsula in the Second Half of the Twentieth Century
Authors: García JoséAgustín , Gallego María Cruz , Serrano Antonio , Vaquero JoséManuel
Published: January 2007

In this study trends in extreme rainfall over the Iberian Peninsula at a daily scale in the second half of the twentieth century have been detected and analyzed. For this goal 35 stations evenly distributed over the region of study covering the period 1958–97 have been studied. Two different approaches have been used. The first one consists of the nonparametric Mann–Kendall test and the Sen method. The second approach is based on the statistical theory of extreme values, involving time-dependent parameters in order to be able to reflect possible temporal changes in the frequency distribution. Results from both methods agree, confirming the reliability of the analysis. Negative trends are found for the west and southwest of the Iberian Peninsula in spring and winter. In autumn a spatial dipolar pattern appears, but trends are not so evident.
British science, Chinese skill and Assam tea
Authors: Sharma Jayeeta
Published: January 2007

This article traces the workings of science, ideology and economy which integrated Assam into imperial and global commodity networks as a tea ‘garden’. It discusses how imperial botanists and their colonial subordinates conceived of botanic gardens as a conduit for transplanting plants such as tea into British-ruled territories. While this clearly served British economic interests, they stressed its vital scientific and strategic implications. The East India Company was willing to finance the Indian tea enterprise when its profitable China monopoly ended. Although the tea plant was found growing wild in Assam, importing Chinese plants and skilled growers was a priority. Nineteenth-century ideas about race science had an important impact, denigrating Assam's plants and people as wild and uncultured, as compared to the civilised lineage of the Chinese. However, as the British acquired greater knowledge about tea cultivation, planters began to prefer bringing cheap, unskilled labourers from other parts of India as indentured coolies to work on harsh terms. For Assam's local people, their high hopes of the tea garden were belied. Their participation in the colonial tea enterprise was mostly limited to subsidiary roles as the region became a dependent outpost of global extractive capitalism.