Fibronectin modulates the endocannabinoid system through the cAMP/PKA pathway during human sperm capacitation

Fibronectin (Fn) enhances human sperm capacitation via the cAMP/PKA pathway, and the endocannabinoid system participates in this process. Moreover, Fn has been linked to endocannabinoid system components in different cellular models, even though no evidence of such interactions in human sperm is available. Normal semen samples were evaluated over a 4-year period. Our findings suggest that (a) the capacitating effects of Fn were reversed by preincubating the sperm with a cannabinoid receptor 1 (CB1) or transient receptor potential cation channel subfamily V member 1 (TRPV1) antagonist (p < 0.001 and p < 0.05, respectively); (b) cooperation between CB1 and TRPV1 may exist (p < 0.01); (c) the activity of specific fatty acid amide hydroxylase (FAAH) decreased after 1 min (p < 0.01) and increased after 60 min (p < 0.01) of capacitation in the presence of Fn; (d) the effects of Fn on FAAH activity were prevented by preincubating spermatozoa with a protein kinase A (PKA) inhibitor (p < 0.01); (e) Fn modulated both the cyclic adenosine monophosphate concentration and PKA activity (p < 0.05) during early capacitation; and (f) FAAH was a PKA substrate modulated by phosphorylation. These findings indicate that Fn stimulates human sperm capacitation via the cAMP/PKA pathway through modulation of the endocannabinoid system. Understanding the functional competence of human spermatozoa is essential for facilitating clinical advances in infertility treatment and for developing novel contraceptive strategies.Fil: Martínez León, Eduardo Antonio. Universidad de Antofagasta; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Osycka Salut, Claudia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Signorelli, Janetti. Universidad de Antofagasta; ChileFil: Kong, Milene. Universidad de Antofagasta; ChileFil: Morales, Patricio. Universidad de Antofagasta; ChileFil: Perez Martinez, Silvina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Díaz, Emilce Silvina. Universidad de Antofagasta; Chil

A simheuristic algorithm for solving an integrated resource allocation and scheduling problem

Modern companies have to face challenging configuration issues in their manufacturing chains. One of these challenges is related to the integrated allocation and scheduling of resources such as machines, workers, energy, etc. These integrated optimization problems are difficult to solve, but they can be even more challenging when real-life uncertainty is considered. In this paper, we study an integrated allocation and scheduling optimization problem with stochastic processing times. A simheuristic algorithm is proposed in order to effectively solve this integrated and stochastic problem. Our approach relies on the hybridization of simulation with a metaheuristic to deal with the stochastic version of the allocation-scheduling problem. A series of numerical experiments contribute to illustrate the efficiency of our methodology as well as their potential applications in real-life enterprise settings

An analysis of culture as a tourism commodity

The notion of culture has been the object of multidisciplinary studies attempting, with difficulty, to define this polyhedral social concept expressed in symbolic representations. Culture has a significant role in tourism functioning as an internationally promoted commodity, a role that has often been the subject of debates among academics concerned about the vilification of culture’s primary social role. This article analyzes the complexity of the concept of culture in combination with the characteristics of a product, as conceived in marketing, focusing on the levels of product theory from Kotler and Armstrong. The research is based on secondary data analysis in the discussion. This incorporates culture’s symbolic representations, its tangibility and intangibility, its multiplicity of interpretations and meanings, the ambiguous status of ownership by the buyer and its versatility to satisfy consumers’ needs while functioning as a unit of identification for a society. As a product culture presents a unique configuration with a construct of four different dimensions highlighting the need for special consideration in culture’s marketing process. The research could also be considered as a platform for future investigations on the subject and as supporting material in education

Slower-than-Light Spin-1/2 Particles Endowed with Negative Mass Squared

Extending in a straightforward way the standard Dirac theory, we study a quantum mechanical wave-equation describing free spinning particles --which we propose to call "Pseudotachyons" (PT's)-- which behave like tachyons in the momentum space, but like subluminal particles (v<c) in the ordinary space. This is allowed since, as it happens in every quantum theory for spin-1/2 particles, the momentum operator (that is conserved) and the velocity operator (that is not) are independent operators, which refer to independent quantities. As a consequence, at variance with ordinary Dirac particles, for PT's the average velocity is not equal to the classical velocity, but actually to the velocity "dual" of the classical velocity. The speed of PT's is therefore smaller than the speed of light. Since a lot of experimental data seems to involve a negative mass squared for neutrinos, we suggest that these particles might be PT's, travelling, because of their very small mass, at subluminal speeds very close to c. The present theory is shown to be separately invariant under the C, P, T transformations; the covariance under Lorentz transformations is also proved. Furthermore, we derive the kinematical constraints linking 4-impulse, 4-velocity and 4-polarization of free PT'sComment: LaTeX; 20 page

Droplet-shaped waves: Causal finite-support analogs of X-shaped waves

A model of steady-state X-shaped wave generation by a superluminal (supersonic) pointlike source infinitely moving along a straight line is extended to a more realistic causal scenario of a source pulse launched at time zero and propagating rectilinearly at constant superluminal speed. In the case of infinitely short (delta) pulse, the new model yields an analytical solution, corresponding to the propagation-invariant X-shaped wave clipped by a droplet-shaped support, which perpetually expands along the propagation and transversal directions, thus tending the droplet-shaped wave to the X-shaped one.Comment: 14 pages, 6 figure

An analog fluid model for some tachyonic effects in field theory

We consider the sound radiation from an acoustic point-like source moving along a supersonic ("space-like") trajectory in a fluid at rest. We call it an acoustic "tachyonic" source. We describe the radiation emitted by this supersonic source. After quantizing the acoustic perturbations, we present the distribution of phonons generated by this classical tachyonic source and the classical wave interference pattern.Comment: 14 pages, 5 figures, accepted for publication in Mod. Phys. Lett.

The Tolman "Antitelephone" Paradox: Its Solution by Tachyon Mechanics

Some recent experiments led to the claim that something can travel faster than light in vacuum. However, such results do not seem to place relativistic causality in jeopardy. Actually, it is possible to solve also the known causal paradoxes, devised for "faster than $c$" motion: even if this is not widely recognized. Here we want to show, in detail and rigorously, how to solve the oldest causal paradox, originally proposed by Tolman, which is the kernel of so many further tachyon paradoxes. The key to the solution is a careful application of {\em tachyon mechanics}, that can be unambiguously derived from special relativity

About Superluminal motions and Special Relativity: A Discussion of some recent Experiments, and the solution of the Causal Paradoxes

Some experiments, performed at Berkeley, Cologne, Florence, Vienna, Orsay, Rennes, etc., led to the claim that something seems to travel with a group velocity larger than the speed c of light in vacuum. Various other experimental results seem to point in the same direction: For instance, localized wavelet- type solutions to Maxwell equations have been found, both theoretically and experimentally, that travel with superluminal speed. [Even muonic and electronic neutrinos [it has been proposed] might be "tachyons", since their square mass appears to be negative]. With regard to the first-mentioned experiments, it was recently claimed by Guenter Nimtz that those results with evanescent waves (or tunneling photons) imply superluminal signal and impulse transmission, and therefore violate Einstein causality. In this note we want to stress that, on the contrary, all such results do not place relativistic causality in jeopardy, even if they referred to actual tachyonic motions: In fact, Special Relativity can cope even with superluminal objects and waves. For instance, it is possible (at least in microphysics) to solve also the known causal paradoxes, devised for faster than light motion, although this is not widely recognized yet. Here we show, in detail and rigorously, how to solve the oldest causal paradox, originally proposed by Tolman, which is the kernel of many further tachyon paradoxes (like J.Bell's, F.A.E.Pirani's, J.D.Edmonds' and others'). The key to the solution is a careful application of tachyon mechanics, as it unambiguously follows from special relativity. At Last, in one of the two Appendices, we propose how to evaluate the group-velocity in the case of evanescent waves. [PACS nos.: 03.30.+p; 03.50.De; 41.20.Jb; 73.40.Gk; 84.40.Az; 42.82.Et ]Comment: LaTeX file: 26 pages, with 5 Figures (and two Appendices). The original version of this paper appeared in the Journal below

Exact Microscopic Entropy of Non-Supersymmetric Extremal Black Rings

In this brief note we show that the horizon entropy of the largest known class of non-supersymmetric extremal black rings, with up to six parameters, is exactly reproduced for all values of the ring radius using the same conformal field theory of the four-charge four-dimensional black hole. A particularly simple case is a dipole black ring without any conserved charges. The mass gets renormalized, but the first corrections it receives can be easily understood as an interaction potential energy. Finally, we stress that even if the entropy is correctly reproduced, this only implies that one sector of chiral excitations has been identified, but an understanding of excitations in the other sector is still required in order to capture the black ring dynamics.Comment: 7 pages. v2: minor improvements, ref adde

Polyunsaturated fatty acid-derived lipid mediators and T cell function

Copyright © 2014 Nicolaou, Mauro, Urquhart and Marelli-Berg . This is an open- access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms