bluuebunny/crossref_metadata_2025 huggingface dataset:
Interspecific variation in the response of growth, crown morphology, and survivorship to light of six tree species in the conifer belt of the Bhutan Himalayas
Authors: Gratzer Georg , Darabant Andras , Chhetri Purna B , Rai Prem Bahadur , Eckmüllner Otto
Published: June 2004

The responses of radial and height growth, plant architecture, and the probability of mortality of saplings to varying light levels were quantified for six tree species in temperate conifer forests of the Bhutan Himalayas. Increases in growth with increasing light were comparable with those of high latitude tree species but lower than those of tropical tree species and temperate species in North America. The shade-tolerant species Tsuga dumosa (D. Don.) Eichler showed the strongest increase in radial growth at low light and reached asymptotic growth early. It had the deepest crowns in low light and a low decrease of leader growth with decreasing light. It represents a continuous growth type, which invests in height rather than lateral growth under low light conditions. Betula utilis D. Don. showed greater increases in radial growth and a higher mortality at low light than the more shade-tolerant Abies densa Griff., in keeping with the trade-off between survivorship and growth at low light. Picea spinulosa Griff, Larix griffithiana Carriére, and Pinus wallichiana A.B. Jackson showed small increases in growth at low light levels. The latter two species showed no capacity to adapt their morphology in response to changing light levels, which resulted in higher probabilities of mortality at lower light levels. Differences in the probability of mortality at different light levels were more pronounced than differences in the light-growth response, underlining the importance of survivorship at low light for successional dynamics.
Analytical methods for defining standclearcut edge effects demonstrated for N mineralization
Authors: Redding Todd E , Hope Graeme D , Schmidt Margaret G , Fortin Marie-Josée
Published: June 2004

Edge effects are becoming an important forest management consideration, but information regarding the influence of edges on N cycling variables has not been well documented. In addition, the quantification of edge effects can benefit from the application of complementary spatial analysis methods. Forest floor N mineralization and environmental variables were intensively measured 5 years after harvest along transects crossing the north and south edges of a 1-ha clearcut, in a high-elevation Engelmann spruce  subalpine fir forest. Wavelet analysis and depth-of-edge influence (DEI) methods were used to locate and measure the spatial extent of edge effects on N mineralization. Then variance partitioning (partial redundancy analysis) was used to examine the influence of edges on N mineralization relative to the influence of other environmental factors. Initial NO3-N content and net nitrification markedly increased in the opening within 26 m of each edge. Net ammonification did not exhibit obvious edge-related spatial patterns. Spatial patterns of nitrification appeared to be more closely related to spatial changes in substrate quality than to soil temperature and moisture. Results of the wavelet and DEI analyses provided quantification of locations and functional extents of edge effects.
Assessment of the frost hardiness of shoots of silver birch (Betula pendula) seedlings with and without controlled exposure to freezing
Authors: Luoranen Jaana , Repo Tapani , Lappi Juha
Published: June 2004

Frost hardiness (FH) of the shoots of silver birch (Betula pendula Roth) container seedlings was assessed by electrolyte leakage (EL), visual scoring of damage to the stem (SB), and whole-plant viability tests after controlled exposure to freezing during frost hardening. FH was calculated as the temperature causing a 50% or 10% increase in electrolyte leakage (ELT50, ELT10), stem browning (SBT50, SBT10), proportion of damaged seedlings (DT50, DT10) or mortality (LT50, LT10). Heterogeneous variances in error are considered in the estimation of the above indices by nonlinear regression of the logistic function. A method for computing the standard error of the estimated temperature causing 10% damage is described. The FH estimates by the most reliable method of assessment SBT50were then compared with electrical impedance parameters (EIS) and water contents (WC) measured without controlled exposure to freezing. Comparison of FH assessment methods showed that ELT50estimated the DT10, SBT50, and DT50well. The WC of the uppermost 10 cm of stem decreased in early autumn, when FH was above 10 °C. When the rapid increase in FH started, WC stabilized. Intracellular and extracellular resistance measured by EIS of unexposed stems correlated positively with FH.
Investigation of limestone ecotypes of white spruce based on a provenance test series
Authors: Lesser Mark R , Cherry Marilyn , Parker William H
Published: June 2004

Previous laboratory and field studies have presented evidence for the existence of limestone ecotypes in white spruce (Picea glauca (Moench) Voss). Remeasurements of the range-wide 410 series of provenance trials were used for further evaluation of the existence of these ecotypes. In 2001, heights were measured of 23 provenances grown at four test sites in Ontario, all located south of 46°N. Bedrock classification for test sites and provenances by limestone or non-limestone parent material was done using a 1993 data set of the Ontario Geological Survey. Analysis of variance revealed significant differences among test sites and provenances only. No significant interactions consistent with the existence of limestone ecotypes were detected. This finding is in contrast to that of an earlier field study that detected a strong interaction between test site and provenance bedrock type (p < 0.001). Examination of the relative performance of individual provenances from limestone and non-limestone bedrock types revealed differences in performance at the four different test sites but few instances supporting the existence of limestone ecotypes. Although these more recent results generally support a pattern of between-stand variation in southern Ontario, they do not disprove the existence of limestone ecotypes, owing to the nature of the 410-series test design and the classification of provenances according to bedrock type instead of actual soil analyses.
A mixture model-based approach to the classification of ecological habitats using Forest Inventory and Analysis data
Authors: Zhang Lianjun , Liu Chuangmin , Davis Craig J
Published: June 2004

A Gaussian mixture model (GMM) is used to classify Forest Inventory and Analysis (FIA) plots into six ecological habitats in the northeastern USA. The GMM approach captures intra-class variation by modeling each habitat class as a mixture of subclasses of Gaussian distributions. The classification is achieved based on the appropriate posterior probability. The GMM classifier outperforms a traditional statistical method (i.e., linear discriminant analysis or LDA), and produces similar overall accuracy rates to a commonly used neural network model (i.e., multi-layer perceptrons or MLP). For the classifications of individual ecological habitats, however, MLP produces better (or same) producers' classification accuracies for five of the six ecological habitats than does GMM. But the GMM's accuracy rates are more consistent (92%97%) across the six ecological habitats than those of the MLP model (82%99%). This study shows that GMM offers an attractive alternative for modeling the complex stand structure and relationships between variables in mixed-species forest stands.
Physiological involvement of placental endothelin-1 and prostaglandin F2αin uteroplacental circulatory disturbance in pregnant rats exposed to heat stress
Authors: Nakamura Hiroyuki , Matsuzaki Ichiyo , Hatta Kotaro , Ogino Keiki
Published: June 2004

Several studies suggest that heat stress affects placental functions including uteroplacental circulation, subsequently leading to pregnancy failure and birth weight reduction. To clarify the involvement of endothelin and placental prostaglandin (PG) systems in the uteroplacental circulation during heat stress, we examined the effects of i.v. administration of the endothelin receptor antagonist bosentan and the cyclooxygenase inhibitor indomethacin on uteroplacental blood flow and on placental PGE2and PGF2αlevels and their 13,14-dyhydro-15-keto-metabolites (PGEM and PGFM, respectively) in heat-exposed or non-heat-exposed pregnant rats. The administration of bosentan or indomethacin did not change uteroplacental blood flow in non-heat-exposed pregnant rats. In contrast, heat reduced uteroplacental blood flow in pregnant rats, but the reduction was reversed by the administration of bosentan or indomethacin before heat exposure. Heat did not change placental PGE2or PGEM levels, but in pregnant rats it increased placental PGF2αand PGFM levels, which were reversed by bosentan or indomethacin. Our results suggest that the activation of placental endothelin receptor and PGF2αsystems are involved in the uteroplacental circulatory disturbances produced by heat. PGF2αsystems activated by heat may be involved in the vasoconstricting effects of endothelin-A and -B receptors during heat exposure.Key words: blood flow, endothelin, placenta, pregnancy, prostaglandin.
Immediate constraint-induced movement therapy causes local hyperthermia that exacerbates cerebral cortical injury in rats
Authors: DeBow Suzanne B , McKenna John E , Kolb Bryan , Colbourne Frederick
Published: June 2004

Constraint-induced movement therapy (CIMT), which involves restraint of the nonimpaired arm coupled with physiotherapy for the impaired arm, lessens impairment and disability in stroke patients. Surprisingly, immediate ipsilateral forelimb immobilization exacerbates brain injury in rats. We tested whether immediate ipsilateral restraint for 7 days aggravates injury after a devascularization lesion in rats. Furthermore, we hypothesized that ipsilateral restraint aggravates injury by causing hyperthermia. In experiment 1, each rat received two lesions, one in the motor cortex and one in the visual cortex. Ipsilateral restraint increased only the motor cortex lesion. In additional rats, no differences in core temperature occurred after ipsilateral or contralateral restraint. Thus, ipsilateral restraint does not aggravate injury by a systemic side effect. In experiment 2, we hypothesized that ipsilateral restraint causes hyperthermia in the region surrounding the initial cortical lesion. Brain temperature, measured via telemetry, was significantly higher (~1 °C for 24 h) with ipsilateral restraint. A third experiment similarly found that ipsilateral restraint aggravates injury and causes local cortical hyperthermia and that contralateral restraint with externally induced mild hyperthermia aggravates injury. In conclusion, immediate ipsilateral restraint aggravates injury apparently by localized events that include hyperthermia. Caution must be exercised in applying early CIMT to humans, as hyperthermia is detrimental.Key words: stroke, rehabilitation, hyperthermia, physical therapy techniques, motor cortex.
Rapid biphasic arteriolar dilations induced by skeletal muscle contraction are dependent on stimulation characteristics
Authors: Mihok Marika L , Murrant Coral L
Published: June 2004

To test the hypothesis that measurable changes in microvasculature dilation occur in response to a single short-duration tetanic contraction, we contracted three to five skeletal muscle fibres of the hamster cremaster muscle microvascular preparation (in situ) and evaluated the response of an arteriole overlapping the active muscle fibres. Arteriolar diameter (baseline diameter = 16.4 ± 0.9 µm, maximum diameter = 34.7 ± 1.2 µm) was measured before and after a single contraction resulting from a range of stimulus frequencies (4, 10, 20, 30, 40, 60, and 80 Hz) within a 250- or 500-ms train. Four and 10 Hz produced a significant dilation at 2.9 ± 0.4 and 6.5 ± 2.8 s, respectively, within a 250-ms train and 3.0 ± 0.2 and 6.1 ± 1.3 s, respectively, within a 500-ms train. Biphasic dilations were observed within a 250-ms train at 20 Hz (at 3.9 ± 0.9 and 22.1 ± 4.3 s), 30 Hz (at 2.7 ± 0.3 and 17.5 ± 2.9 s), and 40 Hz (at 3.8 ± 0.4 and 23.2 ± 2.6 s) and within a 500-ms train at 20 Hz (at 4.8 ± 0.4 and 31.9 ± 3.8 s) and 30 Hz (at 3.4 ± 0.3 and 27.6 ± 3.0 s). A single dilation was observed within a 250-ms train at 60 Hz (at 5.1 ± 0.7 s) and 80 Hz (at 14.2 ± 3.3 s) and within a 500-ms train at 40 Hz (at 9.9 ± 3.2 s), 60 Hz (at 7.9 ± 2.1 s), and 80 Hz (at 13.4 ± 4.0 s). We have shown that a single contraction ranging from a single twitch (4 Hz, 250 ms) to fused tetanic contractions produces significant arteriolar dilations and that the pattern of dilation is dependent on the stimulus frequency and train duration.Key words: arteriole, skeletal muscle, hyperaemia, vasodilation, stimulus frequency.
Positive inotropism in mammalian skeletal muscle in vitro during and after fatigue
Authors: Reading S A , Murrant C L , Barclay J K
Published: June 2004

We tested the hypothesis that positive inotropic factors decrease fatigue and improve recovery from fatigue in mammalian skeletal muscle in vitro. To induce fatigue, we stimulated mouse soleus and extensor digitorum longus (EDL) to perform isometric tetanic contractions (50 impulses·s–1 for 0.5 s) at 6 contractions·min–1 for 60 min in soleus and 3 contractions·min–1 for 20 min in EDL. Muscles were submerged in Krebs–Henseleit bicarbonate solution (Krebs) at 27 °C gassed with 95% nitrogen – 5% carbon dioxide (anoxia). Before and for 67 min after the fatigue period, muscles contracted at 0.6 contractions·min–1 in 95% oxygen – 5% carbon dioxide (hyperoxia). We added a permeable cAMP analog (N6, 2′-O-dibutyryladenosine 3′:5′-cyclic monophosphate at 10–3 mol·L–1 (dcAMP)), caffeine (2×10–3 mol·L–1, or Krebs as vehicle control at 25 min before, during, or at the end of the fatigue period. In soleus and EDL, both challenges added before fatigue significantly increased developed force but only caffeine increased developed force when added during the fatigue period. At the end of fatigue, the decrease in force in challenged muscles was equal to or greater than in controls so that the force remaining was the same or less than in controls. EDL challenged with dcAMP or caffeine at any time recovered more force than controls. In soleus, caffeine improved recovery except when added before fatigue. With dcAMP added to soleus, recovery was better after challenges at 10 min and the end of the fatigue period. Thus, increased intracellular concentrations of cAMP and (or) Ca2+ did not decrease fatigue in either muscle but improved recovery from fatigue in EDL and, in some conditions, in soleus.Key words: skeletal muscle contractility, isometric tetanic contractions, hyperoxia, anoxia.
CALCULATIONS OF STRESS-DEFORMED STATE OF LOW-DENSITY MATERIALS AND ITS APPLICATIONS TO BORON CARBIDE DURING EXPLOSIVE LOADING
Authors: PEIKRISHVILI A. , LEMIS-PETROPOULOS P. , KAPAKLIS V. , POLITIS C.
Published: June 2004

Using hot explosive compacting technology and consolidating B 4 C powders in two stage at high temperatures enabled us to obtain compacts with high value of hardness and near theoretical density. This work contains results of calculations of B 4 C stress state under the shock loading that is being distributed evenly at a constant rate through the boundary retaining samples.
MAGNETO-TRANSPORT AND MAGNETO-OPTICAL PROPERTIES OF FERROMAGNETIC (III,Mn)V SEMICONDUCTORS: A REVIEW
Authors: SINOVA JAIRO , JUNGWIRTH T. , ČERNE JOHN
Published: June 2004

Rapid developments in material research of metallic ferromagnetic (III,Mn)V semiconductors over the past few years have brought a much better understanding of these complex materials. We review here some of the main developments and current understanding of the bulk properties of these systems within the metallic regime, focusing principally on the magneto-transport and magneto-optical properties. Although several theoretical approaches are reviewed, the bulk of the review uses the effective Hamiltonian approach, which has proven useful in describing many of these properties namely in (Ga,Mn)As and (In,Mn)As. The model assumes a ferromagnetic coupling between Mn d-shell local moments mediated by holes in the semiconductor valence band.
LONG-TIME RELAXATION ON SPIN LATTICE AS A MANIFESTATION OF CHAOTIC DYNAMICS
Authors: FINE BORIS V.
Published: June 2004

The long-time behavior of the infinite temperature spin correlation functions describing the free induction decay in nuclear magnetic resonance and intermediate structure factors in inelastic neutron scattering is considered. These correlation functions are defined for one-, two- and three-dimensional infinite lattices of interacting spins, both classical and quantum. It is shown that, even though the characteristic time-scale of the long-time decay of the correlation functions considered is non-Markovian, the generic functional form of this decay is either simple exponential or exponential multiplied by cosine. This work contains (i) the summary of the existing experimental and numerical evidence of the above asymptotic behavior; (ii) theoretical explanation of this behavior; and (iii) semi-empirical analysis of various factors discriminating between the monotonic and the oscillatory long-time decays. The theory is based on a fairly strong conjecture that, as a result of chaos generated by spin dynamics, a Brownian-like Markovian description can be applied to the long-time properties of ensemble average quantities on a non-Markovian time-scale. The formalism resulting from that conjecture can be described as "correlated diffusion in finite volumes."
IR AND RAMAN SPECTROSCOPIC INVESTIGATIONS OF Cr2O3-TeO2-B2O3-SrO GLASSES
Authors: ARDELEAN I. , MUREŞAN N. , PĂŞCUŢĂ P.
Published: June 2004

The Cr 2 O 3 content influence on the structure of 70 TeO 2·25 B 2 O 3·5 SrO glasses, was investigated by infrared and Raman spectroscopies. The results show that BO 3 and BO 4 are among the main structural units in the investigated glasses, together with TeO 3 and TeO 4 units. The presence of chromium ions located in the glass network is well evidenced in the IR and Raman spectra.
THE LANDAU–POMERANCHUK–MIGDAL EFFECT FOR AMORPHOUS AND CRYSTALLINE MATTER
Authors: UGGERHØJ ULRIK I.
Published: June 2004

Presented are the conclusions drawn from experimental investigations of the Landau–Pomeranchuk–Migdal (LPM) effect in amorphous and crystalline targets as well as the preceding and ensuing theoretical activities. In amorphous targets the phenomenon is by now well studied both experimentally and theoretically and is at a mature stage where extrapolations to other energies or materials are well founded. In crystalline targets, the effect is not as well studied as it is harder to deconvolute from other effects like e.g. multiple photon emission. Even in this case, though, a seemingly consistent picture of the suppression mechanism that alters the effective radiation length emerges. Due to the increased scattering, crystals might be used to explore hitherto untested regimes of the LPM effect.
A PARALLEL SOLVER FOR REACTION–DIFFUSION SYSTEMS IN COMPUTATIONAL ELECTROCARDIOLOGY
Authors: COLLI FRANZONE PIERO , PAVARINO LUCA F.
Published: June 2004

In this work, a parallel three-dimensional solver for numerical simulations in computational electrocardiology is introduced and studied. The solver is based on the anisotropic Bidomain cardiac model, consisting of a system of two degenerate parabolic reaction–diffusion equations describing the intra and extracellular potentials of the myocardial tissue. This model includes intramural fiber rotation and anisotropic conductivity coefficients that can be fully orthotropic or axially symmetric around the fiber direction. The solver also includes the simpler anisotropic Monodomain model, consisting of only one reaction–diffusion equation. These cardiac models are coupled with a membrane model for the ionic currents, consisting of a system of ordinary differential equations that can vary from the simple FitzHugh–Nagumo (FHN) model to the more complex phase-I Luo–Rudy model (LR1). The solver employs structured isoparametric Q1 finite elements in space and a semi-implicit adaptive method in time. Parallelization and portability are based on the PETSc parallel library. Large-scale computations with up to O(107) unknowns have been run on parallel computers, simulating excitation and repolarization phenomena in three-dimensional domains.
ON A LUBRICATION PROBLEM WITH FOURIER AND TRESCA BOUNDARY CONDITIONS
Authors: BOUKROUCHE MAHDI , ŁUKASZEWICZ GRZEGORZ
Published: June 2004

The asymptotic behavior of a Stokes flow with Fourier boundary condition on one part on the boundary and Tresca free boundary friction condition on the other, when one dimension of the fluid domain tends to zero is studied. The strong convergence of the velocity is proved, a specific Reynolds equation is obtained, and the uniqueness of the limit velocity and pressure distributions is established.
DUALITY, MONOTONICITY AND THE WIGNER–YANASE–DYSON METRICS
Authors: GRASSELLI M. R.
Published: June 2004

We show that, for each value of α∈(-1, 1), the only Riemannian metrics on the space of positive definite matrices for which the ∇(α) and ∇(-α) connections are mutually dual are matrix multiples of the Wigner–Yanase–Dyson metric. If we further impose that the metric be monotone, then this set is reduced to scalar multiples of the Wigner–Yanase–Dyson metric.
Autocorrelation and Volume in the Chinese Stock Market
Authors: Groenewold Nicolaas
Published: June 2004

This paper reports an empirical analysis of the relationship between return autocorrelation, trading volume and volatility, following the seminal paper by Campbell, Grossman and Wang (1992) using data for A shares traded on the Shanghai and Shenzhen stock exchanges for the period 1992–2002. Campbell et al. argue that autocorrelation of returns will be negatively related to trading volume given that market makers will need to be rewarded with higher returns for accommodating noise traders. For our full sample we find remarkably consistent support for the CGW hypothesis and results — return autocorrelations are negatively but non-linearly related to lagged trading volume and less strongly to volatility. These results are quite robust with respect to different messures of volume and volatility. We argue that this is a striking result in view of the substantial differences between the US market in the 1960s, 1970s and 1980s and the Chinese market of the 1990s. The relationship proves to be unstable over short sub-periods although whether this is due to the relatively short sample we use or to the inherent instability of the Chinese market in its first decade of operation will not be clear until much longer data sets are available for Chinese stock prices.
The Constant Elasticity of Variance Models: New Evidence from S&P 500 Index Options
Authors: Lee C. F. , Wu Ta-Peng , Chen Ren-Raw
Published: June 2004

The seminal work by Cox (1975, 1996), MacBeth and Merville (1979, 1980) and Emanuel and Macbeth (1982) show that, both theoretically and empirically, the constant elasticity of variance option model (CEV) is superior to the Black–Scholes model in explaining market prices. In this paper, we extend the MacBeth and Merville (1979, 1980) research by using a European contract (S&P 500 index options). We find supportive evidence to the MacBeth and Merville results although our sample is not subject to American premium biases. Furthermore, we reduce the approximation errors by using the non-central chi-square probability functions proposed by Shroder (1989).
LONG TERM BEHAVIOR OF DICHOTOMOUS STOCHASTIC DIFFERENTIAL EQUATIONS IN HILBERT SPACES
Authors: VAN GAANS ONNO , VERDUYN LUNEL SJOERD
Published: June 2004

We study existence of invariant measures for semilinear stochastic differential equations in Hilbert spaces. The noise is infinite dimensional, white in time, and colored in space. We show that if the equation is exponentially dichotomous in the sense that the semigroup generated by the linear part is hyperbolic and the Lipschitz constants of the nonlinearities are not too large, then existence of a solution with bounded mean squares implies existence of an invariant measure. Moreover, we show that every bounded solution satisfies a certain "Cauchy condition", which implies that its distributions converge weakly to a limit distribution.
THIS ELUSIVE OBJECTIVE EXISTENCE
Authors: MOHRHOFF ULRICH
Published: June 2004

Zurek's existential interpretation of quantum mechanics suffers from three classical prejudices, including the belief that space and time are intrinsically and infinitely differentiated. These compel him to relativize the concept of objective existence in two ways. The elimination of these prejudices makes it possible to recognize the quantum formalism's ontological implications — the relative and contingent reality of spatiotemporal distinctions and the extrinsic and finite spatiotemporal differentiation of the physical world — which in turn makes it possible to arrive at an unqualified objective existence. Contrary to a widespread misconception, viewing the quantum formalism as being fundamentally a probability algorithm does not imply that quantum mechanics is concerned with states of knowledge rather than states of Nature. On the contrary, it makes possible a complete and strongly objective description of the physical world that requires no reference to observers. What objectively exists, in a sense that requires no qualification, is (i) the trajectories of macroscopic objects, whose fuzziness is empirically irrelevant, (ii) the properties and values of whose possession these trajectories provide indelible records, and (iii) the fuzzy and temporally undifferentiated states of affairs that obtain between measurements and are described by counterfactual probability assignments.
PROBABILITIES FROM ENVARIANCE?
Authors: MOHRHOFF ULRICH
Published: June 2004

Zurek claims to have derived Born's rule noncircularly in the context of an ontological no-collapse interpretation of quantum states, without any "deus ex machina imposition of the symptoms of classicality". After a brief review of Zurek's derivation it is argued that this claim is exaggerated if not wholly unjustified. In order to demonstrate that Born's rule arises noncircularly from deterministically evolving quantum states, it is not sufficient to assume that quantum states are somehow associated with probabilities and then prove that these probabilities are given by Born's rule. One has to show how irreducible probabilities can arise in the context of an ontological no-collapse interpretation of quantum states. It is argued that the reason why all attempts to do this have so far failed is that quantum states are fundamentally algorithms for computing correlations between possible measurement outcomes, rather than evolving ontological states.
QUANTUM CODES CONSTRUCTED FROM BINARY CYCLIC CODES
Authors: LI RUIHU , LI XUELIANG
Published: June 2004

In this paper, we use 2-cyclotomic cosets of modulo n and generator polynomials to describe binary cyclic codes of length N=2αn with n odd. We discuss the conditions under which two cyclic codes [Formula: see text] and [Formula: see text] can be used to construct quantum codes by CSS construction or Steane's construction. Using the results of Chen, Promhouse and Tavares, and Castagnoli et al., we study the quantum codes that can be constructed from binary cyclic codes of length N=2αn with n odd and n≤99, and α≤2. We find that except the quantum codes constructed by Steane, there are also some very interesting quantum codes constructed from repeated-root cyclic codes, and some of the quantum codes constructed by Steane can be improved.
GEOMETRY OF DECOMPOSITION DEPENDENT EVOLUTIONS OF MIXED STATES
Authors: KULT DAVID , SJÖQVIST ERIK
Published: June 2004

We examine evolutions where each component of a given decomposition of a mixed quantal state evolves independently in a unitary fashion. The geometric phase and parallel transport conditions for this type of decomposition dependent evolution are delineated. We compare this geometric phase with those previously defined for unitarily evolving mixed states, and mixed state evolutions governed by completely positive maps.
GLOBAL DREAMS — LOCAL TEAMS: RHETORIC AND REALITIES OF TRANSNATIONAL INNOVATION
Authors: BERGGREN CHRISTIAN
Published: June 2004

This article challenges notions of transnational innovation and global project teams as imperatives for modern management of innovation. Proceeding from an account of the localised dynamics of a radical technology innovation project in the early 1970s, the article reviews the strategy theorists of the 1990s, who proclaimed the virtues of cross-border innovation processes. Their expectations of international synergies and world-wide learning are confronted with the realities and local harvesting in a transatlantic innovation project at a European multinational. An account follows of a radical innovation project at the firm, which was the scene of the introductory study. Now, 25 years later this industrial technology company had become part of a far-flung multinational, which according to popular management theorists was the model of international innovation. The case account highlights the surprising similarities between the two projects, and the sustained importance of intensive local interaction and commitment in uncertain innovation projects.
INNOVATION AND ORGANISATIONAL SIZE IN IRISH SMES: AN EMPIRICAL STUDY
Authors: MCADAM RODNEY , REID RENEE S. , GIBSON DAVID A.
Published: June 2004

The aim of this paper is to conduct an empirical study to explore the influence of size category on innovation incorporation in Irish SMEs. Changes in markets and in large organisation strategies have resulted in the need for SMEs to re-examine and modify their competitive strategies to increase innovation. Although there is some literature on innovation incorporation in SMEs, there is a lack of direct studies on this issue, with a reliance on related but indirect studies such as Reengineering and New product development in SMEs. Furthermore, there is a paucity of studies and data on the innovation incorporation in different organisational size categories within SMEs.

This study uses a grounded SME innovation model developed from earlier studies as the basis of a questionnaire survey of 2086 SMEs in Northern Ireland. The results indicate that SME organisational size categories has a significant effect on innovation incorporation in relation to leadership, people and culture, TQM/CI, product and process and Knowledge and information management.
Endothelium-derived reactive oxygen species and endothelin-1 attenuate NO-dependent pulmonary vasodilation following chronic hypoxia
Authors: Jernigan Nikki L. , Walker Benjimen R. , Resta Thomas C.
Published: June 2004

Vasodilatory responses to exogenous nitric oxide (NO) are diminished following exposure to chronic hypoxia (CH) in isolated, perfused rat lungs. We hypothesized that both endothelium-derived reactive oxygen species (ROS) and endothelin-1 (ET-1) mediate this attenuated NO-dependent pulmonary vasodilation following CH. To test this hypothesis, we examined vasodilatory and vascular smooth muscle (VSM) Ca2+ responses to the NO donor spermine NONOate in UTP-constricted, isolated pressurized small pulmonary arteries from control and CH rats. Consistent with our previous findings in perfused lungs, we observed attenuated NO-dependent vasodilation following CH in endothelium-intact vessels. However, in endothelium-denuded vessels, responses to spermine NONOate were augmented in CH rats compared with controls, thus demonstrating an inhibitory influence of the endothelium on NO-dependent reactivity following CH. Whereas both the ROS scavenger tiron and the ETA receptor antagonist BQ-123 augmented NO-dependent reactivity in endothelium-intact vessels from CH rats, neither fully restored vasodilatory responses to those observed following endothelium denudation in vessels from CH rats. In contrast, the combination of tiron and BQ-123 or the nonselective ET receptor antagonist PD-145065 enhanced NO responsiveness in endothelium-intact vessels from CH rats similar to that observed following endothelium denudation. We conclude that both endothelium-derived ROS and ET-1 attenuate NO-dependent pulmonary vasodilation following CH. Furthermore, CH augments pulmonary VSM reactivity to NO.
Intergenerational consequences of fetal programming by in utero exposure to glucocorticoids in rats
Authors: Drake Amanda J. , Walker Brian R. , Seckl Jonathan R.
Published: June 2004

Epidemiological studies linking low birth weight and subsequent cardiometabolic disease have given rise to the hypothesis that events in fetal life permanently program subsequent cardiovascular risk. The effects of fetal programming may not be limited to the first-generation offspring. We have explored intergenerational effects in the dexamethasone-programmed rat, a model in which fetal exposure to excess glucocorticoid results in low birth weight with subsequent adult hyperinsulinemia and hyperglycemia underpinned by increased activity of the key hepatic gluconeogenic enzyme, phospho enolpyruvate carboxykinase (PEPCK). We found that the male offspring of female rats that had been exposed prenatally to dexamethasone, but were not manipulated in their own pregnancy, also had reduced birth weight (5.66 ± 0.06 vs. 6.12 ± 0.06 g, P < 0.001), glucose intolerance, and elevated hepatic PEPCK activity (5.7 ± 0.6 vs. 3.3 ± 0.2 nmol·min−1·mg protein−1, P < 0.001). These effects resolved in a third generation. Similar intergenerational programming was observed in offspring of male rats exposed prenatally to dexamethasone mated with control females. The persistence of such programming effects through several generations, transmitted by either maternal or paternal lines, indicates the potential importance of epigenetic factors in the intergenerational inheritance of the “programming phenotype” and provides a basis for the inherited association between low birth weight and cardiovascular risk factors.
Absence of the cholecystokinin-A receptor deteriorates homeostasis of body temperature in response to changes in ambient temperature
Authors: Nomoto Shigeki , Ohta Minoru , Kanai Setsuko , Yoshida Yuki , Takiguchi Soichi , Funakoshi Akihiro , Miyasaka Kyoko
Published: June 2004

The circadian rhythm of the body core temperature (Tc) and the effects of changes in ambient temperatures on the homeostasis of Tc in Otsuka Long Evans Tokushima Fatty (OLETF) rats, which are naturally occurring cholecystokinin (CCK)-A receptor (CCK-AR) gene knockout (−/−) rats, were examined. In addition, the peripheral responses to warming or cooling of the preoptic and anterior hypothalamic region (PO/AH) were determined. The circadian rhythm of Tc in OLETF rats was similar to that in Long-Evans Tokushima (LETO) rats; this rhythm was characterized by a higher Tc during the dark period and a lower Tc during the light period. When the ambient temperature was changed within the limits of 0°C to 30°C, the changes in Tc of LETO rats were associated with the changes in ambient temperature, whereas those in OLETF rats were dissociated from the temperature changes. The OLETF rats showed a large hysteresis. The peripheral responses to warming or cooling of PO/AH, including shivering of the neck muscle and changes in skin temperature of the tail and footpad, were similar in OLETF and LETO rats. To confirm the role of CCK-AR in the regulation of body temperature, the values of Tc in the CCK-AR(−/−) mice were compared with those in CCK-B receptor (CCK-BR) (−/−), CCK-AR(−/−)BR(−/−), and wild-type mice. In the mice, the circadian rhythms of Tc were the same, regardless of the genotype. Mice without CCK-AR showed larger hysteresis than mice with CCK-AR. From these results, we conclude that the lack of CCK-AR causes homeostasis of Tc in rats and mice to deteriorate.
Independent and Convergent Signals From the Pontomedullary Reticular Formation Contribute to the Control of Posture and Movement During Reaching in the Cat
Authors: Schepens Bénédicte , Drew Trevor
Published: June 2004

We have addressed the nature of the postural control signals contained within the discharge activity of neurons in the pontomedullary reticular formation, including reticulospinal neurons, during a reaching task in the cat. We recorded the activity of 142 neurons during ipsilateral reaching movements that required anticipatory postural adjustments (APAs) in the supporting limbs to maintain equilibrium. Discharge activity in 82/142 (58%) neurons was significantly increased before the onset of the reach. Most of these neurons discharged either in a phasic (22/82), tonic (10/82), or phasic/tonic (41/82) pattern. In each of these 3 groups, the onset of the discharge activity in some neurons was temporally related either to the go signal or to the onset of the movement. In many neurons, one component of the discharge sequence was better related to the go signal and another to the onset of the movement. Based on our previous behavioral study during the same task, we suggest that reticular neurons in which the discharge activity is better related to the go signal contribute to the initiation of the APAs that precede the movement. Neurons in which the discharge activity is better related to the movement signal might contribute to the initiation of the movement and to the production of the postural responses that accompany that movement. Together our results suggest the existence of neurons that signal posture and movement independently and others that encode a convergent signal that contributes to the control of both posture and movement.
On non‐midpoint locally uniformly rotund normability in Banach spaces
Authors: Mirmostafaee A. K.
Published: June 2004

We will show that if X is a tree‐complete subspace of
ℓ∞, which contains c0, then it does not
admit any weakly midpoint locally uniformly convex
renorming. It follows that such a space has no
equivalent Kadec renorming.
A remark on the intersection of the conjugates of the base ofquasi‐HNN groups
Authors: Mahmood R. M. S.
Published: June 2004

Quasi‐HNN groups can be characterized as a generalization of HNN
groups. In this paper, we show that if G∗ is a quasi‐HNN
group of base G, then either any two conjugates of G are
identical or their intersection is contained in a conjugate of
an associated subgroup of G.
Tissue factor messenger RNA levels in leukocytes compared with tissue factor antigens in plasma from patients in hypercoagulable state caused by various diseases
Authors: Sase Tomohiro , Kamikura Yuko , Kaneko Toshihiro , Abe Yasunori , Nishioka Junji , Nobori Tsutomu , Shiku Hiroshi , Wada Hideo
Published: June 2004

We compared the levels of tissue factor (TF) mRNA in leukocytes with plasma TF antigens of patients in hypercoagulable state caused by various diseases. Flow cytometric analysis showed absence of TF antigen expression on neutrophils and monocytes in healthy subjects but strong expression in both cell types of patients with infections. TF mRNA levels in leukocytes were low in healthy subjects but they were significantly elevated in patients with underlying diseases of disseminated intravascular coagulation (DIC), especially in acute myeloid leukaemia (AML) and infections. TF mRNA levels in leukocytes were significantly high in patients with all diseases except those with thrombosis, and plasma TF antigen levels were significantly high in all diseases. TF mRNA in leukocytes and plasma TF antigen levels were significantly high in patients with overt-DIC, and TF mRNA/antigen ratio was significantly high in patients with overt-DIC. In patients with solid cancers, TF mRNA and TF mRNA/antigen ratio were significantly higher in patients with metastases than those without. TF mRNA levels in leukocytes and plasma levels of TF antigen did not correlate in normal subjects and all patients, but they tended to be correlated in patients with AML, infections or overt-DIC. Our analysis suggests that TF expression in leukocytes plays an important role in various diseases but the expression level does not always correlate with plasma levels of TF antigen.
Platelet activation, coagulation and angiogenesis in breast and prostate carcinoma
Authors: Caine Graham , Lip Gregory , Stonelake Paul , Ryan Peter , Blann Andrew
Published: June 2004

In health, haemostasis and angiogenesis are tightly regulated processes, but may become deregulated in cancer. Recent evidence suggests that platelet activation may link these processes as platelets can release angiogenic factors such as vascular endothelial growth factor (VEGF). Furthermore, inflammation has also been implicated in regulating both coagulation and angiogenesis, possibly by activating platelets directly and increasing, for example, plasma fibrinogen. We hypothesized relationships between plasma markers of the processes in two common forms of cancer. Plasma levels of VEGF (reflecting angiogenesis), soluble P-selectin, (marking platelet activation), tissue factor [TF], fibrinogen and fibrin D-dimer (coagulation markers), and serum levels of IL-6 (inflammation) were measured by ELISA in 30 patients with biopsy-proven breast cancer, 30 patients with biopsy-proven prostate cancer, and 30 ageand sex-matched controls for each group. Prostate specific antigen was also measured in the men. Release of VEGF from IL-6 stimulated platelets was assessed by ELISA. Plasma levels of IL-6 (P <0.02), VEGF, soluble P-selectin, fibrinogen, and fibrin D-dimer (all p <0.01) were significantly raised in breast cancer, whereas VEGF, soluble P-selectin, fibrin D-dimer (all p <0.01) and fibrinogen (p <0.05) were significantly raised in prostate cancer. Significant correlations were found between IL-6 and VEGF (p <0.01), and IL-6 and soluble P-selectin (p = 0.038) in breast cancer. Further experiments demonstrated an in vitro IL-6 induced dose-dependent release of VEGF from platelets. In conclusion, strong relationships between IL6 and VEGF, but not with coagulation or platelet markers, and release of VEGF from IL-6 stimulated platelets, suggest a role for inflammation and platelets in angiogenesis.
Manganese-induced integrin affinity maturation promotes recruitment of αVβ3 integrin to focal adhesions in endothelial cells: evidence for a role of phosphatidylinositol 3-kinase and Src
Authors: Dormond Olivier , Ponsonnet Lionel , Hasmim Meriem , Foletti Alessandro , Rüegg Curzio
Published: June 2004

Integrin activity is controlled by changes in affinity (i.e. ligand binding) and avidity (i.e. receptor clustering). Little is known, however, about the effect of affinity maturation on integrin avidity and on the associated signaling pathways. To study the effect of affinity maturation on integrin avidity, we stimulated human umbilical vein endothelial cells (HUVEC) with MnCl2 to increase integrin affinity and monitored clustering of β1 and β3 integrins. In unstimulated HUVEC, β1 integrins were present in fibrillar adhesions, while αVβ3 was detected in peripheral focal adhesions. Clustered β1 and β3 integrins expressed high affinity/ligand-induced binding site (LIBS) epitopes. MnCl2-stimulation promoted focal adhesion and actin stress fiber formation at the basal surface of the cells, and strongly enhanced mAb LM609 staining and expression of β3 high affinity/LIBS epitopes at focal adhesions. MnCl2-induced αVβ3 clustering was blocked by a soluble RGD peptide, by wortmannin and LY294002, two parmacological inhibitors of phosphatidylinositol 3-kinase (PI 3-K), and by over-expressing a dominant negative PI 3-K mutant protein. Conversely, over-expression of active PI 3-K and pharmacological inhibiton of Src with PP2 and CGP77675, enhanced basal and manganese-induced αVβ3 clustering. Transient increased phosphorylation of protein kinase B/Akt, a direct target of PI 3K, occurred upon manganese stimulation. MnCl2 did not alter β1 integrin distribution or β1 high-affinity/LIBS epitope expression. Based on these results, we conclude that MnCl2-induced αVβ3 integrin affinity maturation stimulates focal adhesion and actin stress fiber formation, and promotes recruitment of high affinity αVβ3 to focal adhesions. Affinity-modulated αVβ3 clustering requires PI3-K signaling and is negatively regulate by Src.
ADP secretion and subsequent P2Y12 receptor signalling play a crucial role in thrombin-induced ERK2 activation in human platelets
Authors: Fälker Knut , Lange Danica , Presek Peter
Published: June 2004

Stimulating human platelets with thrombin induces the activation of the extra cellular signal-regulated kinase 2 (ERK2). We demonstrate that this effect is highly dependent on ADP secretion and P2Y12 receptor signalling. AR-C69931MX (10 µM), a specific antagonist of the Gi-coupled P2Y12 ADP receptor, inhibits ERK2 activation induced by thrombin. Antagonists of the Gq-coupled P2Y1 ADP receptor, A3P5P (500 µM) and MRS2179 (100 µM), have no effect. ADP and its more potent analogue 2-methylthio-ADP alone (both up to 100 µM) do not induce ERK2 activation. Furthermore, we show that the inhibitory effect of AR-C69931MX on ERK2 activation induced by 0.1 U/ml thrombin as well as on platelet aggregation can be bypassed by epinephrine (1 and 10 µM), whereas epinephrine alone has no effect. Epinephrine acts on platelets mainly via α2A-adrenergic receptors, which, like P2Y12 receptors, couple to inhibitory G proteins. In addition, 2-methylthioADP as well as epinephrine provoke ERK2 activation at a thrombin concentration that alone has no detectable effect (0.05 U/ml). Thromboxane A2 (TXA2), which, like ADP, is released by activated platelets, acts as a positive feedback mediator. Stimulating the Gq-coupled TXA2-receptor with U46619 (10 µM), which leads to ADP secretion and P2Y12 receptor dependent platelet aggregation, also induces P2Y12-related ERK2 activation. The inhibition of U46619-induced ERK2 activation and platelet aggregation by AR-C69931MX are also rescued by epinephrine. Pretreatment with aspirin inhibits ERK2 activation induced by 0.1 U/ml thrombin, but has no effect at high concentrations of thrombin. The combination of U46619 and thrombin, at concentrations which alone have no effect, provokes ERK2 activation, suggesting that thrombin and released TXA2 act synergistically. Our data indicate that both primary signalling through Gq, which evokes ADP secretion, as well as subsequent coupling via Gi by the P2Y12 receptor are required for ERK2 activation.