Bleaching in foraminifera with algal symbionts: implications for reef monitoring and risk assessment

Abstrac

Fairness and Managerial Rights in Canadian Arbitral Jurisprudence

Cet article étudie le devoir d'équité lorsqu'il est applique aux clauses des droits de la direction des conventions collectives devant les cours civiles pour conclure, à partir de décisions arbitrales et judiciaires récentes, qu'il s'agit jusqu'à un certain point d'une affaire classée, même si elle peut exiger encore quelques clarifications. Le devoir d'équité, qui a été transpose du droit administratif dans la jurisprudence arbitrale, représentait une deuxième attaque contre la théorie des droits traditionnels ou résiduaires concernant l'exercice de la discrétion patronale. La pensée traditionnelle soutient que les arbitres ne peuvent pas reformer des décisions de l'employeur, à moins que cela ne soit prévu dans les conventions collectives. La première et plus importante attaque contre la théorie traditionnelle s'incarna dans la théorie des « droits partages », qui prit de l'ampleur vers le milieu des années 1950, mais déclina au cours de la décennie et demie suivante. Le deuxième défi se présenta quand le devoir d'équité s'est transpose dans la jurisprudence arbitrale vers la fin des années 1970. L'article décrit la jurisprudence entourant cet emprunt du droit administratif ainsi que son abandon subséquent de plus en plus généralise par beaucoup d'arbitres et de tribunaux. Après avoir analyse et critique ces décisions, l'auteur soutient qu'il devrait y avoir équité et uniformité de traitement dans les arbitrages et que la décision à suivre est celle de Metropolitan Toronto Board of Commissioners of Police, (1981) 124 D.L.R. (3d) 684. Ainsi, le devoir d'équité peut prendre place à l'intérieur des paramètres de la convention collective, mais là où la clause des droits de la direction confirme clairement ou confère à la direction le droit exclusif et sans entrave de décider certaines questions, un tribunal d'arbitrage est sans compétence pour réviser soit la justesse de la décision, soit le processus par lequel on y est arrive. Des textes explicites à l'effet contraire sont une condition préalable extrêmement importante pour qu'il y ait matière à reformation et les principes du droit administratif sont inappropriés. Au contraire, il faut suivre les règles de l'interprétation des contrats. De fait, la seule exception possible, soit en Colombie britannique, où quelques arbitres ont eu recours aux dispositions statutaires pour élargir leurs pouvoirs de réparation en cette matière, est rejetée par l'auteur. Enfin, si les parties désirent débattre une affaire dans les limites des droits exclusifs de la direction, ils doivent procéder devant le bon forum, c'est-à-dire les tribunaux et non devant un conseil d'arbitrage.This paper examines the duty of fairness as applied to management's rights under collective agreements in common law jurisdictions and concludes from recent arbitral and judicial decisions that it is somewhat of a dead issue, although clarification may be required

Electron transport in the dye sensitized nanocrystalline cell

Dye sensitised nanocrystalline solar cells (Gr\"{a}tzel cells) have achieved solar-to-electrical energy conversion efficiencies of 12% in diffuse daylight. The cell is based on a thin film of dye-sensitised nanocrystalline TiO$_2$ interpenetrated by a redox electrolyte. The high surface area of the TiO$_2$ and the spectral characteristics of the dye allow the device to harvest 46% of the solar energy flux. One of the puzzling features of dye-sensitised nano-crystalline solar cells is the slow electron transport in the titanium dioxide phase. The available experimental evidence as well as theoretical considerations suggest that the driving force for electron collection at the substrate contact arises primarily from the concentration gradient, ie the contribution of drift is negligible. The transport of electrons has been characterised by small amplitude pulse or intensity modulated illumination. Here, we show how the transport of electrons in the Gr\"{a}tzel cell can be described quantitatively using trap distributions obtained from a novel charge extraction method with a one-dimensional model based on solving the continuity equation for the electron density. For the first time in such a model, a back reaction with the I$_3^-$ ions in the electrolyte that is second order in the electron density has been included.Comment: 6 pages, 5 figures, invited talk at the workshop 'Nanostructures in Photovoltaics' to appear in Physica

Macroturbulent Instability of the Flux Line Lattice in Anisotropic Superconductors

A theory of the macroturbulent instability in the system containing vortices of opposite directions (vortices and antivortices) in hard superconductors is proposed. The origin of the instability is connected with the anisotropy of the current capability in the sample plane. The anisotropy results in the appearance of tangential discontinuity of the hydrodynamic velocity of vortex and antivortex motion near the front of magnetization reversal. As is known from the classical hydrodynamics of viscous fluids, this leads to the turbulization of flow. The examination is performed on the basis of the anisotropic power-law current-voltage characteristics. The dispersion equation for the dependence of the instability increment on the wave number of perturbation is obtained, solved, and analyzed analytically and numerically. It is shown that the instability can be observed even at relatively weak anisotropy.Comment: 10 pages, 5 figures, submitted to Physical Review

Response of HTS tapes to a parallel ac magnetic field in the vicinity of the superconducting transition

We have studied the temperature dependence of the ac magnetic susceptibility χ(T) = χ′(T) + iχ″(T) of YBCO tapes in a parallel magnetic field in both the Meissner and vortex states. For the vortex state, we have observed two maximums in the χ″(T) dependence. The position and the magnitude of one of these maxima are described well by the nonlocal critical state model. The second maximum and corresponding kink in the function χ′(T) observed close to the temperature Tc of the superconducting transition are unexpected. The origin of this maximum cannot be explained within the usual notions of the high-temperature superconductivity. We suppose that it is related to some magnetic restructuring in the superconducting layer just above Tc. Our results put a question on the correctness of the interpretation of some previous microwave experiments

Zero Temperature Glass Transition in the Two-Dimensional Gauge Glass Model

We investigate dynamic scaling properties of the two-dimensional gauge glass model for the vortex glass phase in superconductors with quenched disorder. From extensive Monte Carlo simulations we obtain static and dynamic finite size scaling behavior, where the static simulations use a temperature exchange method to ensure convergence at low temperatures. Both static and dynamic scaling of Monte Carlo data is consistent with a glass transition at zero temperature. We study a dynamic correlation function for the superconducting order parameter, as well as the phase slip resistance. From the scaling of these two functions, we find evidence for two distinct diverging correlation times at the zero temperature glass transition. The longer of these time scales is associated with phase slip fluctuations across the system that lead to finite resistance at any finite temperature, while the shorter time scale is associated with local phase fluctuations.Comment: 8 pages, 10 figures; v2: some minor correction

Investigating genome wide DNA methylation in bronchial and lung fibroblasts from healthy individuals and individuals with COPD

Rationale: Lung fibroblasts are implicated in respiratory disease pathology including chronic obstructive pulmonary disease (COPD). Phenotypic differences between fibroblasts isolated from the bronchi versus the lung parenchyma have been described but no studies have compared the cell types on a genome wide scale. DNA methylation is a reversible modification of the DNA structure with the ability to affect cell function via the alteration of gene expression. Here we compared genome wide DNA methylation profiles from bronchial and lung fibroblasts and assessed modification to these profiles in cells isolated from individuals with COPD. Methods: DNA was isolated from lung (LgF) and bronchial fibroblasts (BrF) at passage 4 and bisulphite treated. Site specific, quantitative genome wide methylation was determined using the Illumina 450K Infinium Methylation BeadChip array. Linear modelling and DMRcate functions identified differentially methylated sites and regions respectively between BrF and LgF and from cells isolated from healthy individuals versus those with COPD. Results: 3980 CpG (methylation) sites significantly differed, following Bonferroni correction, between BrF and LgF isolated from healthy individuals. These sites had a broad distribution of effect size, with 240 CpG sites displaying a difference in methylation of >50%. 78 of these sites were validated in a second cohort of matched BrF and LgF isolated from the same individuals. There was genomic proximity to these sites and DMRcate was used to refine the individual CpG sites to 5 regions of interest associated with 5 genes; HLX, TWIST1, CREB5, SKAP2 and PRDM16. Differences in methylation were less pronounced when comparing cells isolated from healthy individuals to those with COPD. In BrF 47 DMRcate regions were identified with a maximum difference in methylation of at least 20%. In LgF 3 DMRcate regions were identified with a maximum difference in methylation of at least 20%. Conclusions: DNA methylation profiles are significantly different between BrF and LgF but only small modifications are associated with COPD. Future work will focus on validating a methylation based marker of lung versus bronchial fibroblasts to differentiate cell types by validating our differential DNA methylation observations with gene/protein expression

An Asymptotic Expansion and Recursive Inequalities for the Monomer-Dimer Problem

Let (lambda_d)(p) be the p monomer-dimer entropy on the d-dimensional integer lattice Z^d, where p in [0,1] is the dimer density. We give upper and lower bounds for (lambda_d)(p) in terms of expressions involving (lambda_(d-1))(q). The upper bound is based on a conjecture claiming that the p monomer-dimer entropy of an infinite subset of Z^d is bounded above by (lambda_d)(p). We compute the first three terms in the formal asymptotic expansion of (lambda_d)(p) in powers of 1/d. We prove that the lower asymptotic matching conjecture is satisfied for (lambda_d)(p).Comment: 15 pages, much more about d=1,2,

Thermoelectric instability induced by a single pulse and alternating current in superconducting tapes of second generation

We have studied the instability of the current flow in a superconducting tape of the second generation and the transition of the tape into the resistive state. Contrary to usually studied quasisteady regimes of the instability development, we consider here the adiabatic case of fast sample heating. Two kinds of measurements of the current-voltage characteristics (CVC) have been performed, specifically, using the tape excitation by a single sineshaped current pulse I(t)=I₀sin(ωt) with different amplitudes I₀ and by a continuous ac current flow. The main results were obtained for the current amplitudes I₀ exceeding the critical current value Ic . We have found that the dynamic CVC are practically reversible for low amplitudes, whereas they become irreversible and assume the N -shaped form for higher current amplitudes. The dynamic CVC are found to change radically if the dissipated energy attains some threshold value Wth which is equal to about 5 mJ/cm for our tapes. Once achieving this energy, the tape transits to the resistive state due to a normal domain formation. The development of instability for a continuous ac current flow was studied for a relatively small amplitude when the energy dissipated per one half-cycle is much lower than Wth. Even in this case, the tape transition to the resistive state occurs owing to an effect of energy accumulation (heat pumping). Due to this pumping, the transition takes place after a definite number of ac current periods when the total accumulated energy reaches the same threshold value Wth. The specific features of dynamic CVC are qualitatively interpreted within an approach where the appearance of the resistive domain is taken into account. Estimations performed on the basis of the CVC agree well with our experimental data. The results obtained can be useful for the design of superconducting fault current limiters

Suppression of the vortex glass transition due to correlated defects with a persistent direction perpendicular to an applied magnetic field

It is found on the basis of the lowest Landau level approach for the Ginzburg-Landau model that, in bulk type II superconductors with strong line disorder directed {\it perpendicularly} to an applied field, the continuous vortex-glass transition is depressed to the low $T$ limit in the limit of weak {\it point} disorder. An anomalous resistive broadening in twin-free YBCO with columnar defects in a field parallel to the layers is discussed based on this theoretical finding. Other phenomena which, we argue, arise indirectly from this mechanism in type II superconductors including correlated defects are also discussed.Comment: 5 pages, 3 figures, Fig.2 and text were modified. To appear in Phys. Rev. B (Rapid Comunication