5,748 research outputs found
Leptoquarks decaying to a top quark and a charged lepton at hadron colliders
We study the sensitivity of the Tevatron and the 7 TeV LHC to a leptoquark S
coupling to a top quark and a charged lepton L (= e, mu, or tau). For the
Tevatron, we focus on the case m_S < m_t, where the leptoquark pair production
cross section is large, and the decay is three-body: S --> W b L^{\pm}. We
argue that existing Tevatron observations could exclude m_S \lsim 160 GeV. For
m_S > m_t, we show that the LHC experiments with low integrated luminosity
could be sensitive to such leptoquarks decaying to tl^{\pm} with l= mu or tau.Comment: 13 pages, 6 figures, minor changes (typos
Interface relaxation in electrophoretic deposition of polymer chains: Effects of segmental dynamics, molecular weight, and field
Using different segmental dynamics and relaxation, characteristics of the
interface growth is examined in an electrophoretic deposition of polymer chains
on a three (2+1) dimensional discrete lattice with a Monte Carlo simulation.
Incorporation of faster modes such as crankshaft and reptation movements along
with the relatively slow kink-jump dynamics seems crucial in relaxing the
interface width. As the continuously released polymer chains are driven (via
segmental movements) and deposited, the interface width grows with the
number of time steps , (--,
which is followed by its saturation to a steady-state value . Stopping the
release of additional chains after saturation while continuing the segmental
movements relaxes the saturated width to an equilibrium value ().
Scaling of the relaxed interface width with the driving field , remains similar to that of the steady-state width. In
contrast to monotonic increase of the steady-state width , the relaxed
interface width is found to decay (possibly as a stretched exponential)
with the molecular weight.Comment: 5 pages, 7 figure
Derived categories of cubic fourfolds
We discuss the structure of the derived category of coherent sheaves on cubic
fourfolds of three types: Pfaffian cubics, cubics containing a plane and
singular cubics, and discuss its relation to the rationality of these cubics.Comment: 18 page
Measurement of Resonance Driving Terms from Turn-by-Turn Data
It has been shown that the Fourier analysis of recorded turn-by-turn tracking data can be used to derive resonance terms of an accelerator. Besides the resonance driving terms, the non-linear one-turn map can be obtained with all non-linearities arising from magnetic imperfections and correction elements. This could be interesting for the LHC which will be a machine that is dominated by strong non-linear fields. The methods works very well for tracking data and is expected to work equally well for turn-by-turn beam data. The precision to which these terms can be determined relies on the frequency analysis tool. To demonstrate the feasibility of the method, measurements of real accelerators are presented in which the beam is kicked once and the beam oscillations are recorded over several thousand turns. Besides the tune, the strengths of resonance driving terms have been measured and the results are compared with numerical calculation
The Importance of Hydration in Wound Healing: Reinvigorating the clinical perspective
Balancing skin hydration levels is important as any disruption in skin integrity will result in disturbance of the dermal water balance. The discovery that a moist wound healing environment actively supports the healing response when compared to a dry environment highlights the importance of water and good hydration levels for optimal wound healing.
The benefits of âwetâ or âhyper-hydratedâ wound healing appears to offer benefits that are similar to those offered by moist wound healing over wounds healing in a dry environment. This suggests that the presence of free water itself during wound healing may not be detrimental to healing but that any adverse effects of wound fluid on tissues is more likely related to the biological components contained within chronic wound exudate (e.g. elevated protease levels).
Appropriate dressings applied to wounds must be able to absorb not only the exudate but also retain this excess fluid together with its protease solutes while concurrently preventing desiccation. This is particularly important in the case of chronic wounds where peri-wound skin barrier properties are compromised and there is increased permeation across the injured skin barrier. This review discusses the importance of appropriate levels of hydration in skin with a particular focus on the need for optimal hydration levels for effective healing
Abel-Jacobi maps for hypersurfaces and non commutative Calabi-Yau's
It is well known that the Fano scheme of lines on a cubic 4-fold is a
symplectic variety. We generalize this fact by constructing a closed p-form
with p=2n-4 on the Fano scheme of lines on a (2n-2)-dimensional hypersurface Y
of degree n. We provide several definitions of this form - via the Abel-Jacobi
map, via Hochschild homology, and via the linkage class, and compute it
explicitly for n = 4. In the special case of a Pfaffian hypersurface Y we show
that the Fano scheme is birational to a certain moduli space of sheaves on a
p-dimensional Calabi--Yau variety X arising naturally in the context of
homological projective duality, and that the constructed form is induced by the
holomorphic volume form on X. This remains true for a general non Pfaffian
hypersurface but the dual Calabi-Yau becomes non commutative.Comment: 34 pages; exposition of Hochschild homology expanded; references
added; introduction re-written; some imrecisions, typos and the orbit diagram
in the last section correcte
Tame Functions with strongly isolated singularities at infinity: a tame version of a Parusinski's Theorem
Let f be a definable function, enough differentiable. Under the condition of
having strongly isolated singularities at infinity at a regular value c we give
a sufficient condition expressed in terms of the total absolute curvature
function to ensure the local triviality of the function f over a neighbourhood
of c and doing so providing the tame version of Parusinski's Theorem on complex
polynomials with isolated singularities at infinity.Comment: 20 page
Vaccinations par le B. C. G. dans le département du Cher. Une expérience sur le plan départemental
La rĂ©action dâhĂ©magglutination type Middlebrook- Dubos, effectuĂ©e chez 118 bovins avec des hĂ©maties de mouton et la tuberculine soit dite « prĂ©cipitĂ©e » soit I.P. 48 de l âInstitut Pasteur de Paris, a Ă©tĂ© positive dans 81 p. 100 des cas de tuberculose Ă©volutive, avec des pourcentages variables selon la nature des lĂ©sions puisquâelle a Ă©tĂ© maxima (100 p. 100) pour les lĂ©sions pleuro-pulmonaires, forte (87,3 p. 100) pour les lĂ©sions de plusieurs organes ou gĂ©nĂ©ralisĂ©es, et faible (50 p. 100) pour les lĂ©sions ganglio-pulmonaires . Par contre, elle a Ă©tĂ© le plus souvent nĂ©gative lorsque les lĂ©sions Ă©taient limitĂ©es aux ganglions pulmonaires et de type casĂ©o-calcaire. Cette rĂ©action a Ă©tĂ© trĂšs rarement (4,0 p. 100) positive chez des animaux apparemment sains, et toujours dâailleurs Ă des taux faibles. Bien que des recherches portant sur de nombreux sĂ©rums soient encore nĂ©cessaires (pour prĂ©ciser en particulier la signification des rĂ©actions positives chez les bovidĂ©s apparemment sains), on peut admettre, semble-t-il, dĂšs maintenant, quâune rĂ©action nettement positive (5> 1/147) traduit toujours une tuberculose Ă©volutive atteignant plusieurs organes. Elle paraĂźt pouvoir dĂšs maintenant rendre des services pour le diagnostic de la tuberculose et lâĂ©tude de la phtisiogenĂšse chez les bovidĂ©s
Corporate Hierarchies and the Size of Nations: Theory and Evidence
Corporate organization varies within a country and across countries with country size. The paper starts by establishing some facts about corporate organization based on unique data of 660 Austrian and German corporations. The larger country (Germany) has larger firms with flatter more decentral corporate hierarchies compared to the smaller country (Austria). Firms in the larger country change their organization less fast than firms in the smaller country. Over time firms have been introducing less hierarchical organizations by delegating power to lower levels of the corporation. We develop a theory which explains these facts and which links these features to the trade environment that countries and firms face. We introduce firms with internal hierarchies in a Krugman (1980) model of trade. We show that international trade and the toughness of competition in international markets induce a power struggle in firms which eventually leads to decentralized corporate hierarchies. We offer econometric evidence which is consistent with the models predictions
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