bluuebunny/crossref_metadata_2025 huggingface dataset:
A numerical method for one-dimensional action functionals of photonic band-gap structures
Authors: Xie F , Reid G , Valluri S
Published: June 2004

Photonic band gaps (PBG), photonic analogues of electronic semiconductor band gaps, have attracted much attention recently because of numerous potential applications in communications and computing. Aközbek and John (Phys. Rev. E, 57, 2287 (1998).) developed a variational model of such band gaps, using action functionals, where solitary waves are expanded in terms of a finite orthonormal basis. These expansions to finite order N converged to solitary waves. The nonlinear polynomial equations for the coefficients in the expansions, have nonunique solutions. Our paper, makes a study of the multiplicity of the solutions for one-dimensional photonic band-gap structures. It is found that the nonuniqueness grows dramatically with the order of the expansion N. We use homotopy, which continuously deforms the solutions of exactly solvable systems, into the solutions of the systems to be solved with new results in numeric algebraic geometry, such that all solutions are determined. We used Maple 7 to obtain the polynomial equations for the variational coefficients, extending Aközbek and John's approach. A homotopy-based package PHCpack was used to solve the systems for N ≤ 4 and a linearization-extrapolation method was developed to find real solutions for N ≥ 5. The results are compared with the exact soliton solutions and their convergence behavior is discussed. The interplay of geometrical, topological and variational methods is seen in these interesting physical band-gap structures. PACS Nos.: 42.65.Tg, 42.70.Qs, 02.30.Xx, 02.70.Wz
Penetration of spheres into loose granular media
Authors: de Bruyn J R , Walsh A M
Published: June 2004

We study the penetration of steel spheres dropped vertically into a container of loosely packed, small glass beads. We find that the penetration depth of the spheres increases linearly with the incident momentum of the projectile, but with a zero-momentum intercept that can be either positive or negative. This behavior can be understood by modelling the granular medium as a non-Newtonian fluid with a yield stress and an effective viscosity. We derive the scaling behavior of the viscosity and find agreement with our experimental results. PACS Nos.: 45.70.n, 83.80.Fg, 47.50.+d
POSITIVE DEFINITE MAPS, REPRESENTATIONS AND FRAMES
Authors: DUTKAY DORIN ERVIN
Published: June 2004

We present a unitary approach to the construction of representations and intertwining operators. We apply it to the C*-algebras, groups, Gabor-type unitary systems and wavelets. We give an application of our method to the theory of frames, and we prove a general dilation theorem which is in turn applied to specific cases, and we obtain in this way a dilation theorem for wavelets.
TORSION AND GRAVITATION: A NEW VIEW
Authors: ARCOS H. I. , DE ANDRADE V. C. , PEREIRA J. G.
Published: June 2004

According to the teleparallel equivalent of general relativity, curvature and torsion are two equivalent ways of describing the same gravitational field. Though equivalent, they act differently: curvature yields a geometric description, in which the concept of gravitational force is absent whereas torsion acts as a true gravitational force, quite similar to the Lorentz force of electrodynamics. As a consequence, the right-hand side of a spinless-particle equation of motion (which would represent a gravitational force) is always zero in the geometric description, but not in the teleparallel case. This means that the gravitational coupling prescription can be minimal only in the geometric case. Relying on this property, a new gravitational coupling prescription in the presence of curvature and torsion is proposed. It is constructed in such a way to preserve the equivalence between curvature and torsion, and its basic property is to be equivalent to the usual coupling prescription of general relativity. According to this view, no new physics is connected with torsion, which is just an alternative to curvature in the description of gravitation. An application of this formulation to the equations of motion of both a spinless and a spinning particle is discussed.
EXACT SOLUTION OF THE MASSLESS DKP EQUATION IN A NONSTATIONARY GÖDEL-TYPE COSMOLOGICAL UNIVERSE
Authors: HAVARE ALI , AYDOGDU OKTAY , YETKIN TAYLAN
Published: June 2004

In this paper the massless Duffin–Kemmer–Petiau equation in a nonstationary rotating, causal Gödel-type cosmological background is studied. Exact solutions of the corresponding field equation are obtained and used to calculate the frequency spectrum of photon in nonstationary Gödel-type universe. To compare the results found with the classical field solutions, we also solved Maxwell's equations as given in the appendix.
CAN CONVENTIONAL FORCES REALLY EXPLAIN THE ANOMALOUS ACCELERATION OF PIONEER 10/11?
Authors: MBELEK J. P. , MICHALSKI M.
Published: June 2004

A conventional explanation of the correlation between the linear and the angular accelerations of Pioneer 10/11 spacecraft is given. First, the rotational Doppler shift analysis is improved. Finally, a relation between the radio beam reaction force and the spin-rate change is established. Computations are found in good agreement with observational data. Our analysis leads us to the conclusion that the Pioneer anomaly may not necessarily be due to systematics.
THE UNIVERSE AS A NONUNIFORM LATTICE IN FINITE-VOLUME HYPERCUBE I: FUNDAMENTAL DEFINITIONS AND PARTICULAR FEATURES
Authors: SHALYT-MARGOLIN A. E.
Published: June 2004

In this paper a new small parameter associated with the density matrix deformation (density pro-matrix) studied in previous works of the author is introduced into the Generalized Quantum Mechanics (GQM), i.e. quantum mechanics involving description of the Early Universe. It is noted that this parameter has its counterpart in the Generalized Statistical Mechanics. Both parameters offer a number of merits: they are dimensionless, varying over the interval from 0 to 1/4, and assuming in this interval a discrete series of values. Besides, their definitions contain all the fundamental constants. These parameters are very small for the conventional scales and temperatures, e.g. the value of the first parameter is on the order of ≈10-66+2n, where 10-n is the measuring scale and the Planck scale ~ 10-33cm is assumed. The second one is also too small for the conventional temperatures, that is those much below the Planck temperature. It is demonstrated that relative to the first of these parameters the Universe may be considered as a nonuniform lattice in the four-dimensional hypercube with dimensionless finite-length (1/4) edges. And the time variable is also described by one of the above-mentioned dimensions due to the second parameter and Generalized Uncertainty Relation in thermodynamics. In this context the lattice is understood as a deformation rather than approximation.
RESTRICTED PROBLEM OF THREE BODIES WITH NEWTONIAN + YUKAWA POTENTIAL
Authors: KOKUBUN FERNANDO
Published: June 2004

Trajectories of the third body in the Restricted Problem of Three Bodies including a Yukawa term to the Newtonian gravitational potential are analyzed. It is shown that this modified gravitational potential changes some important aspects of the Restricted Problem of Three Bodies. Depending of coupling constant α, motions obtained in the pure Newtonian case are qualitatively different when Yukawa term is included. Depending of coupling parameters α, the nature of dynamics change from regular to chaotic (α<0) or from chaotic to regular (α>0) and in both cases using the same length scales λ.
ON THE INSTANTANEOUS SPECTRUM OF GAMMA-RAY BURSTS
Authors: RUFFINI REMO , BIANCO CARLO LUCIANO , XUE SHE-SHENG , CHARDONNET PASCAL , FRASCHETTI FEDERICO , GURZADYAN VAHE
Published: June 2004

A theoretical attempt to identify the physical process responsible for the afterglow emission of Gamma-Ray Bursts (GRBs) is presented, leading to the occurrence of thermal emission in the comoving frame of the shock wave which gives rise to the bursts. The determination of the luminosities and spectra involves integration over an infinite number of Planckian spectra, weighted by appropriate relativistic transformations, each one corresponding to a different viewing angle in the past light cone of the observer. The relativistic transformations have been computed using the equations of motion of GRBs within our theory, giving special attention to the determination of the equitemporal surfaces. The only free parameter of the present theory is the "effective emitting area" in the shock wave front. A self-consistent model for the observed hard-to-soft transition in GRBs is also presented. When applied to GRB 991216 a precise fit (χ2≃1.078) of the observed luminosity in the 2–10 keV band is obtained. Similarly, detailed estimates of the observed luminosity in the 50–300 keV and in the 10–50 keV bands are obtained.
DYNAMICS OF RELATIVISTIC FLOWS
Authors: CHICONE C. , MASHHOON B. , PUNSLY B.
Published: June 2004

Dynamics of relativistic outflows along the rotation axis of a Kerr black hole is investigated using a simple model that takes into account the relativistic tidal force of the central source as well as the Lorentz force due to the large-scale electromagnetic field which is assumed to be present in the ambient medium. The evolution of the speed of the flow relative to the ambient medium is studied. In the force-free case, the resulting equation of motion predicts rapid deceleration of the initial flow and an asymptotic relative speed with a Lorentz factor of [Formula: see text]. In the presence of the Lorentz force, the long-term relative speed of the clump tends to the ambient electrical drift speed.
MODELING THE VOLATILITY AND EXPECTED VALUE OF A DIVERSIFIED WORLD INDEX
Authors: PLATEN ECKHARD
Published: June 2004

This paper considers a diversified world stock index in a continuous financial market with the growth optimal portfolio (GOP) as reference unit or benchmark. Diversified broadly based indices and portfolios, which include major world stock market indices, are shown to approximate the GOP. It is demonstrated that a key financial quantity is the trend of a world index. It turns out that it can be directly observed since the expected increments of the index equal four times those of the quadratic variation of its square root. Using a world stock index as approximation of the discounted GOP it is shown that, in reality, the trend of the discounted GOP does not vary greatly in the long term. This leads for a diversified world index to a natural model, where the index is a transformed square root process of dimension four. The squared index volatility appears then as the inverse of the square root process. This feature explains most of the properties of an index and its volatility.
Transferring Expert Knowledge: Interpersonal Knowledge Exchange between Extreme Knowledge Workers
Authors: McKenzie Kevin M.
Published: June 2004

This paper reports on a qualitative case study that investigated how consultants source, exchange and deliver specific knowledge within a medium-sized Australian consulting firm to solve client problems in context. This detailed examination of consultants as extreme knowledge workers resulted in the proposal of an eight-stage model of interpersonal knowledge exchange. Utilising the concept of "payload knowledge" (a concept that emerged from the research data as comprising that, specific distillation of knowledge, both tacit and explicit, required to resolve an applied problem in context), respondents described how the interpersonal knowledge exchange process allows them to decontextualise their knowledge and pass it to a requesting consultant, who is able to skilfully recontextualise the content close to its original full meaning. This negotiation process relies on the community's shared language, mental models, social etiquette and cultural norms to compress and funnel the meaning of the payload knowledge to a form that can be transferred meaningfully to a requesting consultant for application to meet the specific need of the client. The process is shown to be predicable in terms of passing through eight identifiable stages, yet unpredictable in terms of knowing how each community interaction will develop into payload knowledge. Within this process, the sourcing, handover, distillation and implementation of payload knowledge are seen as an artistic endeavour, characterised by social community based exchanges that 'hop' the consultants toward their specific contextual need.
Organizational Culture Types and their Relationship with Knowledge Flow and Knowledge Management Success: An Empirical Study in the U.S. Government and Nonprofit Sectors
Authors: Román Juan A. , Ribière Vincent M. , Stankosky Michael
Published: June 2004

The adoption of Knowledge Management programs and systems in the U.S. government and nonprofit sectors is rapidly growing. However, for them to truly be successful, involves more than just implementing a new technology that can be acquire in a box; it requires understanding and integrating the human aspect of it as well as the culture in which they operate. This paper characterizes and evaluates the enterprise culture composition using four organizational culture types (Clan, Adhocracy, Market, and Hierarchy), the existing strategic approach for knowledge flow, and the success of knowledge management systems. A total of 341 responses were collected using a questionnaire. Executives, knowledge managers, and many others can benefit by gaining better understanding and insight in these areas, integrating the human aspect of it to leverage the enterprise intellectual assets in the most efficient and effective way.
An Efficient Graph-Based Method for Parallel Mining Problems
Authors: Chang Chin-Chen , Lin Chih-Yang , Lin Pei-Yu
Published: June 2004

Parallel association rules mining is a noticeable problem in data mining. However, little work has been proposed to deal with three important issues: (1) less memory usage; (2) less communication, among the involved computers, over the network; and (3) load balance among computers. In this paper, we present a graph-based scheme to solve the parallel mining problem by applying independent groups (clusters of maximal cliques). To bring the three issues to a close, the purpose of the independent groups aims at dividing a database into several independent sub-databases, so each sub-database can be employed independently to perform mining algorithms. To emphasis the effectiveness of the graph-based scheme, we adopt the independent groups not only for maximal large itemsets mining but also for general large itemsets mining. The experimental results show that our scheme can improve the efficiency for parallel mining when the independent groups are well-organized and designed.
COMPLETELY AND PARTIALLY INTEGRABLE HAMILTONIAN SYSTEMS IN THE NONCOMPACT CASE
Authors: FIORANI EMANUELE
Published: June 2004

Action-angle coordinates are shown to exist around an instantly compact invariant submanifold of a time-dependent completely integrable Hamiltonian system. Partially integrable Hamiltonian systems are also considered in the noncompact case; a comparison is made with other possible approaches. Results on symplectically complete foliations contained in the Appendix A can be used to give alternative proofs of some propositions.
G2-INVARIANT 7D EUCLIDEAN SUPER YANG–MILLS THEORY AS 7-DIMENSIONAL ANALOGUE OF 3D SUPER-BF THEORY
Authors: MÜLSCH D. , GEYER B.
Published: June 2004

A formulation of NT=1, D=8 Euclidean super Yang–Mills theory with generalized self-duality and reduced Spin(7)-invariance is given which avoids the peculiar extra constraints introduced by Nishino and Rajpoot. Its reduction to seven dimensions leads to the G2-invariant NT=2, D=7 super Yang–Mills theory which may be regarded as a higher-dimensional analogue of the NT=2, D=3 super-BF theory. When further reducing that G2-invariant theory to three dimensions one gets the NT=2 super-BF theory coupled to a spinorial hypermultiplet.
BV QUANTIZATION OF COVARIANT (POLYSYMPLECTIC) HAMILTONIAN FIELD THEORY
Authors: BASHKIROV D.
Published: June 2004

Covariant (polysymplectic) Hamiltonian field theory is the Hamiltonian counterpart of classical Lagrangian field theory. They are quasi-equivalent in the case of almost-regular Lagrangians. This work addresses Batalin–Vilkoviski (BV) quantization of polysymplectic Hamiltonian field theory. We compare BV quantizations of associated Lagrangian and polysymplectic Hamiltonian field systems in the case of almost-regular quadratic Lagrangians.
ON SOME ASPECTS OF THE GEOMETRY OF DIFFERENTIAL EQUATIONS IN PHYSICS
Authors: GRÀCIA XAVIER , MUÑOZ-LECANDA MIGUEL C. , ROMÁN-ROY NARCISO
Published: June 2004

In this review paper, we consider three kinds of systems of differential equations, which are relevant in physics, control theory and other applications in engineering and applied mathematics; namely: Hamilton equations, singular differential equations, and partial differential equations in field theories. The geometric structures underlying these systems are presented and commented on. The main results concerning these structures are stated and discussed, as well as their influence on the study of the differential equations with which they are related. In addition, research to be developed in these areas is also commented on.
THE TIAN–YAU–ZELDITCH ASYMPTOTIC EXPANSION FOR REAL ANALYTIC KÄHLER METRICS
Authors: LOI ANDREA
Published: June 2004

Let M be a compact Kähler manifold endowed with a real analytic and polarized Kähler metric g and let Tmω(x) be the corresponding Kempf's distortion function. In this paper we compute the coefficients of Tian–Yau–Zelditch asymptotic expansion of Tmω(x) using quantization techniques alternative to Lu's computations in [10].
Interleukin-1β induces posttranslational carboxymethylation and alterations in subnuclear distribution of lamin B in insulin-secreting RINm5F cells
Authors: Veluthakal Rajakrishnan , Amin Rajesh , Kowluru Anjaneyulu
Published: June 2004

We examined the effects of interleukin-1β (IL-1β) treatment on the distribution and degradation of lamin B in the nuclear fraction from insulin-secreting RINm5F cells. Western blot analysis indicated that IL-1β treatment caused significant alterations in the redistribution of lamin B, specifically between the Triton X-100-soluble (membrane) and -insoluble (matrix) fractions of the nucleus. IL-1β treatment also increased the lamin carboxymethyltransferase activity and the relative abundance of the carboxymethylated lamin in the nuclear fraction. A significant increase in the relative abundance of lamin B degradation products was also observed in the nuclear fraction from the IL-1β-treated cells. These findings are compatible with a measurable increase in the lamin-degrading caspase-6 activity in IL-1β-treated cells. Confocal microscopic observation of IL-1β-treated cells suggested a significant dissociation of lamin B from the nuclear lamina and its subsequent association with the DNA-rich elements within the nucleus. NG-monomethyl-l-arginine, a known inhibitor of inducible nitric oxide synthetase (iNOS), markedly inhibited IL-1β-induced iNOS gene expression, NO release, caspase-3 and caspase-6 activation, lamin B degradation, and loss of metabolic cell viability, indicating that the observed IL-1β-induced effects on nuclear lamin B involve the intermediacy of NO. Together, our data support the hypothesis that IL-1β treatment results in significant increase in the carboxymethylation of lamin B, which would place lamin B in a strategic location for its degradation mediated by caspases. This could possibly lead to dissolution of the nuclear envelope, culminating in the demise of the effete β-cell.
Norepinephrine-induced calcium signaling and expression of adrenoceptors in avian tendon cells
Authors: Wall Michelle E. , Faber James E. , Yang Xi , Tsuzaki Mari , Banes Albert J.
Published: June 2004

Sympathetic efferent nerves are present in tendons, but their function within tendon is unknown. α1-Adrenoceptors are expressed by a variety of cell types. In the presence of norepinephrine (NE), adrenoceptors activate Gq/11 signaling pathways that subsequently increase intracellular Ca2+ concentration ([Ca2+]ic). It was hypothesized that avian tendon cells express functional adrenoceptors that respond to NE by increasing [Ca2+]ic. Avian tendon cells were analyzed for mRNA expression of α1-adrenoceptors by RT-PCR. Avian tendons expressed the α1A- and α1B-adrenoceptor subtypes. Furthermore, both tendon surface epitenon cells and internal fibroblasts infused with a Ca2+-sensitive dye, fura 2, and stimulated with NE responded by increasing [Ca2+]ic. KMD-3213, an α1A-adrenoceptor antagonist, significantly reduced the Ca2+ response. Other adrenoceptor antagonists had no effect on the Ca2+ response. The absence of extracellular Ca2+ also significantly reduced the response to NE, indicating that Ca2+ influx contributed to the rise in [Ca2+]ic. This study provides the first evidence that tendon cells express adrenoceptors and that the NE-induced Ca2+ response is coupled to the α1A-adrenoceptor subtype.
Induction of uPA release in human peripheral blood lymphocytes by [deamino-Cysl,d-Arg8]-vasopressin (dDAVP)
Authors: Yamaguchi Yoshitaka , Yamada Kenichi , Suzuki Toshikazu , Wu Yu-Ping , Kita Kazuko , Takahashi Shunji , Ichinose Masaharu , Suzuki Nobuo
Published: June 2004

[deamino-Cysl,d-Arg8]-vasopressin (dDAVP), known to be an arginine vasopressin (AVP) V2 receptor agonist, is an agent that increases fibrinolytic activity levels in plasma after its infusion into the human body. However, mechanisms underlying an increase and exact localization of the extrarenal dDAVP-responsive V2 receptor remain unclarified. Two AVP receptors, V1a and V2, and a related oxytocin (OT) receptor were found to be expressed in human lymphocytes. Furthermore, we found an increase of fibrinolytic activity in the medium of peripheral lymphocytes obtained from human volunteers less than 20 min after dDAVP infusion. The increased activity was also detected in the medium after incubating the lymphocytes in the presence of dDAVP in vitro, being highest at 20 min after the incubation. In accord with the increased fibrinolytic activity, the levels of urokinase-type plasminogen activator (uPA) in the medium were also increased. However, there was no significant difference of plasminogen activator inhibitor-1 (PAI-1), pro-uPA, and tissue-type plasminogen activator (tPA) concentrations in the medium between dDAVP treatment and control. When lymphocytes were preincubated with a V2 receptor antagonist [Adamantaneacetyl1,O-Et-d-Tyr2,Val4,Aminobutyryl6,Arg8,9]-vasopressin, the dDAVP-induced uPA increase was diminished. In contrast, preincubation with a V1 receptor antagonist, [β-Mercapto-β,β-cyclopentamethylenepropionyl1,O-Me-Tyr2,Arg8]-vasopressin, prior to dDAVP treatment resulted in a greater increase of the uPA concentration in the medium than with the dDAVP treatment alone. Thus it was suggested that dDAVP may induce uPA release from human lymphocytes via V2 receptor-mediated reaction, and also via cross-talk between V1 and V2 receptors.
Nonacute effects of H-FABP deficiency on skeletal muscle glucose uptake in vitro
Authors: Erol Erdal , Cline Gary W. , Kim Jason K. , Taegtmeyer Heinrich , Binas Bert
Published: June 2004

Heart-type fatty acid-binding protein (H-FABP) is required for high rates of skeletal muscle long-chain fatty acid (LCFA) oxidation and esterification. Here we assessed whether H-FABP affects soleus muscle glucose uptake when measured in vitro in the absence of LCFA. Wild-type and H-FABP null mice were fed a standard chow or high-fat diet before muscle isolation. With the chow, the mutation increased insulin-dependent deoxyglucose uptake by 141% ( P < 0.01) at 0.02 mU/ml of insulin but did not cause a significant effect at 2 mU/ml of insulin; skeletal muscle triglyceride and long-chain acyl-CoA (LCA-CoA) levels remained normal. With the high-fat diet, the mutation increased insulin-dependent deoxyglucose uptake by 190% ( P < 0.01) at 2 mU/ml of insulin, thus partially preventing insulin resistance, and it completely prevented the threefold ( P < 0.001) diet-induced increase of muscle triglyceride levels; however, muscle LCA-CoA levels showed little or no reduction. With both diets, the mutation reduced the basal (insulin-independent) soleus muscle deoxyglucose uptake by 28% ( P < 0.05). These results establish a close relation between FABP-dependent lipid pools and insulin sensitivity and indicate the existence of a nonacute, antagonistic, and H-FABP-dependent fatty acid regulation of basal and insulin-dependent muscle glucose uptake.
Expression of FOXC2 in adipose and muscle and its association with whole body insulin sensitivity
Authors: Di Gregorio Gina B. , Westergren Rickard , Enerback Sven , Lu Tong , Kern Philip A.
Published: June 2004

FOXC2 is a winged helix/forkhead transcription factor involved in PKA signaling. Overexpression of FOXC2 in the adipose tissue of transgenic mice protected against diet-induced obesity and insulin resistance. We examined the expression of FOXC2 in fat and muscle of nondiabetic humans with varying obesity and insulin sensitivity. There was no relation between body mass index (BMI) and FOXC2 mRNA in either adipose or muscle. There was a strong inverse relation between adipose FOXC2 mRNA and insulin sensitivity, using the frequently sampled intravenous glucose tolerance test ( r = −0.78, P < 0.001). However, there was no relationship between muscle FOXC2 and any measure of insulin sensitivity. To separate insulin resistance from obesity, we examined FOXC2 expression in pairs of subjects who were matched for BMI but who were discordant for insulin sensitivity. Compared with insulin-sensitive subjects, insulin-resistant subjects had threefold higher levels of adipose FOXC2 mRNA ( P = 0.03). In contrast, muscle FOXC2 mRNA expression was no different between insulin-resistant and insulin-sensitive subjects. There was no association of adipose or muscle FOXC2 mRNA with either circulating or adipose-secreted TNF-α, IL-6, leptin, adiponectin, or non-esterified fatty acids. Thus adipose FOXC2 is more highly expressed in insulin-resistant subjects, and this effect is independent of obesity. This association between FOXC2 and insulin resistance may be related to the role of FOXC2 in PKA signaling.
Differential regulation of fatty acid trapping in mouse adipose tissue and muscle by ASP
Authors: Faraj May , Cianflone Katherine
Published: June 2004

Acylation-stimulating protein (ASP) is a lipogenic hormone secreted by white adipose tissue (WAT). Male C3 knockout (KO; C3−/−) ASP-deficient mice have delayed postprandial triglyceride (TG) clearance and reduced WAT mass. The objective of this study was to examine the mechanism(s) by which ASP deficiency induces differences in postprandial TG clearance and body composition in male KO mice. Except for increased3H-labeled nonesterified fatty acid (NEFA) trapping in brown adipose tissue (BAT) of KO mice ( P = 0.02), there were no intrinsic tissue differences between wild-type (WT) and KO mice in3H-NEFA or [14C]glucose oxidation, TG synthesis or lipolysis in WAT, muscle, or liver. There were no differences in WAT or skeletal muscle hydrolysis, uptake, and storage of [3H]triolein substrate [in situ lipoprotein lipase (LPL) activity]. ASP, however, increased in situ LPL activity in WAT (+64.8%, P = 0.02) but decreased it in muscle (−35.0%, P = 0.0002). In addition, after prelabeling WAT with [3H]oleate and [14C]glucose, ASP increased3H-lipid retention, [3H]TG synthesis, and [3H]TG-to-[14C]TG ratio, whereas it decreased3H-NEFA release, indicating increased NEFA trapping in WAT. Conversely, in muscle, ASP induced effects opposite to those in WAT and increased lipolysis, indicating reduced NEFA trapping within muscle by ASP ( P < 0.05 for all parameters). In conclusion, novel data in this study suggest that 1) there is little intrinsic difference between KO and WT tissue in the parameters examined and 2) ASP differentially regulates in situ LPL activity and NEFA trapping in WAT and skeletal muscle, which may promote optimal insulin sensitivity in vivo.
Increased Na+ intake during gestation in rats is associated with enhanced vascular reactivity and alterations of K+ and Ca2+ function
Authors: Auger Karine , Beauséjour Annie , Brochu Michèle , St-Louis Jean
Published: June 2004

Gestation is associated with decreased blood pressure and resistance to the effects of vasoconstrictor agents. A recent study showed that pregnant rats, on increased sodium intake, present physiological changes that resemble those observed in preeclampsia. We investigated the effects of sodium supplementation on reactivity and on potassium and Ca2+ channel activity in blood vessels during gestation. Sodium supplements, 0.9% or 1.8% NaCl as drinking water, were given to nonpregnant and pregnant rats for 7 days (last week of gestation). Reactivity to phenylephrine (PE), KCl, arginine vasopressin (AVP), and tetraethylammonium (TEA) was measured in aortic rings under modulation of potassium and calcium channels. TEA, a nonselective K+ channel inhibitor, induced concentration-dependent responses in aortic rings from nonpregnant but not in those from pregnant rats. The response to TEA was restored in rings from pregnant rats after preincubation with 10 mmol/l KCl. Sodium supplementation did not affect the response to TEA in the aortas of pregnant animals. After sodium supplementation, maximum responses to PE and AVP were decreased and increased in aortic rings from nonpregnant and pregnant rats, respectively. Cromakalim (an ATP-sensitive K+ channel activator)-induced inhibition of the responses to the three vasoconstrictors was more striking in aorta from nonpregnant than pregnant rats on regular diet, whereas it produced similar inhibition in tissues from both groups of animals on 0.9% and 1.8% NaCl. NS-1619 (a Ca2+-sensitive K+ activator) elicited heightened effects in the aortas of pregnant animals receiving 0.9% NaCl supplementation. Nifedipine (a Ca2+ channel blocker) caused greater inhibition of the contractile responses in tissues from nonpregnant rats on regular diet, and its action was increased in pregnant rats on sodium-supplemented diets. These data demonstrate that augmented sodium intake during gestation in the rat is linked with the reversal of gestational-associated resistance to vasopressors and indicate that this is an experimental model showing some features of gestational hypertension.
Fullerene derivatives protect against oxidative stress in RAW 264.7 cells and ischemia-reperfused lungs
Authors: Chen Ya-Wen , Hwang Kuo Chu , Yen Cheng-Chieh , Lai Yih-Loong
Published: June 2004

Fullerene derivatives have often been used as effective scavengers for reactive oxygen species (ROS). This study was designed to test whether polyhydroxylated fullerene derivatives [C60(OH)7±2] protect against oxidative stress in cultured RAW 264.7 cells and ischemia-reperfused (IR) lungs. In RAW 264.7 cells, sodium nitroprusside (SNP, 1 mM) and H2O2 (400 μM) caused a marked (90%) decrease in cell viability, and this decrease was dose dependently reversed by pretreatment with C60(OH)7±2 (10–50 μM). The increase in ROS production induced by SNP and H2O2 was significantly suppressed by C60(OH)7±2. Also, the decrease in mitochondrial membrane potential induced by SNP and H2O2 was significantly reversed by C60(OH)7±2. However, high concentration of C60(OH)7±2 (1 and 1.5 mM) lead to cell death (apoptosis or necrosis). In the isolated rat lung, the increases in pulmonary artery pressure and capillary filtration pressure induced by SNP during IR were reversed significantly by C60(OH)7±2 (10 mg/kg). These results indicate that polyhydroxylated fullerene derivatives C60(OH)7±2 at low concentrations protect against oxidative stress in RAW 264.7 cells and IR lungs.
Caffeine Releasable Stores of Ca2+Show Depletion Prior to the Final Steps in Delayed CA1 Neuronal Death
Authors: Xing Hong , Azimi-Zonooz Aryan , Shuttleworth C. William , Connor John A.
Published: June 2004

In addition to their role in signaling, Ca2+ions in the endoplasmic reticulum also regulate important steps in protein processing and trafficking that are critical for normal cell function. Chronic depletion of Ca2+in the endoplasmic reticulum has been shown to lead to cell degeneration and has been proposed as a mechanism underlying delayed neuronal death following ischemic insults to the CNS. Experiments here have assessed the relative content of ryanodine receptor-gated stores in CA1 neurons by measuring cytoplasmic Ca2+increases induced by caffeine. These measurements were performed on CA1 neurons, in slice, from normal gerbils, and compared with responses from this same population of neurons 54–60 h after animals had undergone a standard ischemic insult: 5-min bilateral occlusion of the carotid arteries. The mean amplitude of responses in the postischemic population were less than one-third of those in control or sham-operated animals, and 35% of the neurons from postischemic animals showed very small responses that were ∼10% of the control population mean. Refilling of these stores after caffeine challenges was also impaired in postischemic neurons. These observations are consistent with our earlier finding that voltage-gated influx is sharply reduced in postischemic in CA1 neurons and the hypothesis that the resulting depletion in endosomal Ca2+is an important cause of delayed neuronal death.
Alternative Splicing in the Voltage-Sensing Region of N-Type CaV2.2 Channels Modulates Channel Kinetics
Authors: Lin Yingxin , McDonough Stefan I. , Lipscombe Diane
Published: June 2004

The CaV2.2 gene encodes the functional core of the N-type calcium channel. This gene has the potential to generate thousands of CaV2.2 splice isoforms with different properties. However, the functional significance of most sites of alternative splicing is not established. The IVS3-IVS4 region contains an alternative splice site that is conserved evolutionarily among CaVα1genes from Drosophila to human. In CaV2.2, inclusion of exon 31a in the IVS3-IVS4 region is restricted to the peripheral nervous system, and its inclusion slows the speed of channel activation. To investigate the effects of exon 31a in more detail, we generated four tsA201 cell lines stably expressing CaV2.2 splice isoforms. Coexpression of auxiliary CaVβ and CaVα2δ subunits was required to reconstitute currents with the kinetics of N-type channels from neurons. Channels including exon 31a activated and deactivated more slowly at all voltages. Current densities were high enough in the stable cell lines co-expressing CaVα2δ to resolve gating currents. The steady-state voltage dependence of charge movement was not consistently different between splice isoforms, but on gating currents from the exon 31a-containing CaV2.2 isoform decayed with a slower time course, corresponding to slower movement of the charge sensor. Exon 31a-containing CaV2.2 is restricted to peripheral ganglia; and the slower gating kinetics of CaV2.2 splice isoforms containing exon 31a correlated reasonably well with the properties of native N-type currents in sympathetic neurons. Our results suggest that alternative splicing in the S3-S4 linker influences the kinetics but not the voltage dependence of N-type channel gating.
Factors Governing the Form of the Relation Between Muscle Force and the EMG: A Simulation Study
Authors: Zhou Ping , Rymer William Zev
Published: June 2004

The dependence of the form of the EMG-force relation on key motoneuron and muscle properties was explored using a simulation approach. Surface EMG signals and isometric forces were simulated using existing motoneuron pool, muscle force, and surface EMG models, based primarily on reported properties of the first dorsal interosseous (FDI) muscle in humans. Our simulation results indicate that the relation between electrical and mechanical properties of the individual motor unit level plays the dominant role in determining the overall EMG amplitude-force relation of the muscle, while the underlying motor unit firing rate strategy appears to be a less important factor. However, different motor unit firing rate strategies result in substantially different relations between counts of the numbers of motoneuron discharges and the isometric force. Our simulation results also show that EMG amplitude (estimated as the average rectified value) increases as a result of synchronous discharges of different motor units within the pool, but the magnitude of this increase is determined primarily by the action potential duration of the synchronized motor units. Furthermore, when the EMG effects are normalized to their maximum levels, motor unit synchrony does not exert significant effects on the form of the EMG-force relation, provided that the synchrony level is held similar at different excitation levels.
Persistent Electrical Coupling and Locomotory Dysfunction in the Zebrafish Mutantshocked
Authors: Luna Victor M. , Wang Meng , Ono Fumihito , Gleason Michelle R. , Dallman Julia E. , Mandel Gail , Brehm Paul
Published: June 2004

On initial formation of neuromuscular junctions, slow synaptic signals interact through an electrically coupled network of muscle cells. After the developmental onset of muscle excitability and the transition to fast synaptic responses, electrical coupling diminishes. No studies have revealed the functional importance of the electrical coupling or its precisely timed loss during development. In the mutant zebrafish shocked ( sho) electrical coupling between fast muscle cells persists beyond the time that it would normally disappear in wild-type fish. Recordings from sho indicate that muscle depolarization in response to motor neuron stimulation remains slow due to the low-pass filter characteristics of the coupled network of muscle cells. Our findings suggest that the resultant prolonged muscle depolarizations contribute to the premature termination of swimming in sho and the delayed acquisition of the normally rapid touch-triggered movements. Thus the benefits of gap junctions during early synapse development likely become a liability if not inactivated by the time that muscle would normally achieve fast autonomous function.
Temporal Dynamics of Shape Analysis in Macaque Visual Area V2
Authors: Hegdé Jay , Van Essen David C.
Published: June 2004

The firing rate of visual cortical neurons typically changes substantially during a sustained visual stimulus. To assess whether, and to what extent, the information about shape conveyed by neurons in visual area V2 changes over the course of the response, we recorded the responses of V2 neurons in awake, fixating monkeys while presenting a diverse set of static shape stimuli within the classical receptive field. We analyzed the time course of various measures of responsiveness and stimulus-related response modulation at the level of individual cells and of the population. For a majority of V2 cells, the response modulation was maximal during the initial transient response (40–80 ms after stimulus onset). During the same period, the population response was relatively correlated, in that V2 cells tended to respond similarly to specific subsets of stimuli. Over the ensuing 80–100 ms, the signal-to-noise ratio of individual cells generally declined, but to a lesser degree than the evoked-response rate during the corresponding time bins, and the response profiles became decorrelated for many individual cells. Concomitantly, the population response became substantially decorrelated. Our results indicate that the information about stimulus shape evolves dynamically and relatively rapidly in V2 during static visual stimulation in ways that may contribute to form discrimination.
Class vs. Citizenship: Keywords in German Gender History
Authors: Canning Kathleen
Published: June 2004

Thereis perhaps no more fitting way to honor Vernon Lidtke than to demonstrate, in the form of this essay, that the questions he posed to his students years ago continue to provide a grid for contemplating and analyzing historical subjects, both familiar and new. One such question involved the impact of one concept's transformation upon another: would class persist as a crucial historical category once it had confronted the differences of gender? This question preoccupied me in previous work and I return to it here, taking stock of that which has changed since I first contemplated this question, in the fields of both German and European gender history. Another question that remains an object of debate is the longer-term trajectory of the history of women and gender: how might we define the point at which its work of subversion or revision is complete? What directions might this field take once “mainstream” histories have successfully incorporated its findings? This essay aims to compare the ways in which the keywords class, citizenship, and welfare state have been redefined, expanded, or circumscribed through the turn to culture, language, and gender. This comparative exercise allows me to expand Vernon's original questions to include citizenship, the critical concept in my more recent scholarship, and to review the potentials and promises of main-streaming across the so-called Atlantic divide.
“Hammer Blows”: Work, the Workplace, and the Culture of Masculinity Among Catholic Workers in the Weimar Republic
Authors: Sun Raymond C.
Published: June 2004

Inthe early 1930s German democracy was dying, mired in political gridlock, burdened by four million unemployed, and under assault by Nazis and Communists alike. In the midst of this crisis the Reich Association of Catholic Workers' Clubs and Working Youth (Reichsverband der katholischen Arbeitervereine und der Werkjugend) published a modest anthology entitledDie Arbeit(Work), “dedicated to the poetic glorification of labor.” Editorially justifying the decision to provide Catholic workers with verses at such a time, Ferdinand Göbel, one of the rising young leaders of the Catholic labor movement, argued that the poems, far from serving as a distraction or a momentary boost to morale, would enable workers to find the only true and lasting solution to their predicament. Poetry would lead to an inner, spiritual renewal, a rediscovery by workers that their labor was “not simply to earn bread, but… joyful participation in the act of creation, sacrificial service to humanity and a means of atonement that makes us strong and free within.” Because of this, said Göbel, The modern worker, this man of iron, has discovered his soul. He believes in loyalty and comradeship, in brotherhood and the courage to sacrifice. He hopes in a new humanity. Yes, out of his heavy everyday existence he hammers bridges to the eternal and the divine. He turns hard slave labor into an act of worship.
Crime and Coercion: A Test of Core Theoretical Propositions
Authors: Unnever James D. , Colvin Mark , Cullen Francis T.
Published: June 2004

In his recent Crime and Coercion, Colvin contends that individuals exposed to coercive environments develop social-psychological deficits that enhance their probability of engaging in criminal behavior. Using a sample of 2,472 students from six middle schools, the authors test core propositions of Colvin’s differential coercion theory. Thus, they assess whether delinquent involvement is related to four coercive environments: parental coercion, peer coercion, a coercive school environment, and a coercive neighborhood environment. The authors also assess whether the influence of these coercive environments on delinquency is mediated by four social-psychological deficits: coercive ideation, anger, school social bonds, and parental social bonds. The analysis revealed fairly consistent support for the core propositions of differential coercion theory. Thus, they found that students exposed to coercive environments develop social-psychological deficits and therefore engage in relatively serious delinquent behavior.
Community Boundedness, Personal Relevance, and the Knowledge Gap
Authors: Rucinski Dianne
Published: June 2004

Research on the knowledge gap has explored individual and social factors that may influence the creation, maintenance, and demise of socioeconomically based differences in information gained as the result of communication campaigns. Recent work by Viswanath and colleagues suggests that the extent to which an issue affects members of a community—termed “community boundedness”—may have an independent influence on knowledge acquisition for members of the affected community. This study finds that community boundedness had a positive impact on awareness of a medical insurance program targeted to lower income children, whereas personal relevance did not. Specifically, African Americans and Latinos were more likely to be aware of a medical assistance program during the course of a campaign than were non-Hispanic Whites, controlling for income and personal relevance. The study also documents an inverse knowledge gap in which persons of lower socioeconomic status had greater awareness than did persons of higher socioeconomic status.
Gender Inequality Across Local Wage Hierarchies
Authors: Huffman Matt L.
Published: June 2004

Is gender inequality more severe in higher paying jobs, where there is more at stake? Using a unique definition of jobs—local occupation-industry cells—and multilevel models, I offer the first investigation of how gender wage inequality varies as a function of a job’s ranking in its specific local labor-market context. The results suggest that net of various individual- and job-level controls, (a) female-dominated jobs pay less than comparable male-dominated jobs, (b) the penalty associated with female-dominated jobs is steeper for women, and (c) wage inequality increases as one ascends the wage hierarchy of local labor markets. However, there is no evidence that the tendency for female-dominated jobs to pay less than comparable male-dominated jobs is stronger in high-ranking jobs. Taken together, the results are consistent with the exclusion of women from high-ranking jobs as well as gender segregation within local occupation-industry cells.
Lay Persons’ Versus Psychologists’ Judgments of Psychologically Aggressive Actions by a Husband and Wife
Authors: Follingstad Diane R. , Helff Cynthia M. , Binford Robin V. , Runge Margaret M. , White Jeffrey D.
Published: June 2004

Literature assessing knowledge of and attitudes toward social issues has demonstrated that mental health professionals and lay persons often differ greatly. To add to the normative information in the field of psychological abuse and to determine whether the differences previously found between mental health professionals and lay persons extend to this field, a sample from each group rated psychologically aggressive items by a husband toward his wife. For the 102 items, psychologists were more likely to label the behaviors as “psychological abuse,” but this tendency was due to psychologists considering the behaviors as either “always” or “possibly” abusive, whereas lay persons demonstrated a bimodal response pattern of rating the behaviors as “always” or “never” psychological abuse. Lay persons were much more likely than psychologists to rate items high in terms of severity level, however. The two groups used different contextual factors for determining that a behavior was psychological abuse when they initially were uncertain that it was abusive.