Relativistic Equilibrium Distribution by Relative Entropy Maximization

The equilibrium state of a relativistic gas has been calculated based on the maximum entropy principle. Though the relativistic equilibrium state was long believed to be the Juttner distribution, a number of papers have been published in recent years proposing alternative equilibrium states. However, some of these papers do not pay enough attention to the covariance of distribution functions, resulting confusion in equilibrium states. Starting from a fully covariant expression to avoid this confusion, it has been shown in the present paper that the Juttner distribution is the maximum entropy state if we assume the Lorentz symmetry.Comment: Six pages, no figure

Estimation of Mechanical Vibrations of the LHC Fast Magnetic Measurement System

Current installation of the Large Hadron Collider (LHC) particle accelerator at CERN has required the use of a harmonic coil magnetic measurement system to quantify the magnetic field harmonic quality of the superconducting, twin aperture LHC dipoles. Current and future needs for measuring fast changing magnetic fields necessitates the use of a rotating unit (RU) and associated electronics to drive this long shaft with increased speed and measurement bandwidth. Therefore, the Fast Magnetic Measurement Equipment (FAME) project has been launched to deliver such a system. A primary obstacle to achieving the goals of the FAME project is the possibility of amplifying mechanical vibrations due to increased speeds. This paper presents the methodology and results of an experimental investigation conducted to estimate mechanical vibrations of the long shaft within a cold-bore mounted anti-cryostat at various rotational speeds using magnetic measurements

The Simple Non-degenerate Relativistic Gas: Statistical Properties and Brownian Motion

This paper shows a novel calculation of the mean square displacement of a classical Brownian particle in a relativistic thermal bath. The result is compared with the expressions obtained by other authors. Also, the thermodynamic properties of a non-degenerate simple relativistic gas are reviewed in terms of a treatment performed in velocity space.Comment: 6 pages, 2 figure

Hydrodynamic length-scale selection in microswimmer suspensions

A universal characteristic of mesoscale turbulence in active suspensions is the emergence of a typical vortex length scale, distinctly different from the scale invariance of turbulent high-Reynolds number flows. Collective length-scale selection has been observed in bacterial fluids, endothelial tissue, and active colloids, yet the physical origins of this phenomenon remain elusive. Here, we systematically derive an effective fourth-order field theory from a generic microscopic model that allows us to predict the typical vortex size in microswimmer suspensions. Building on a self-consistent closure condition, the derivation shows that the vortex length scale is determined by the competition between local alignment forces, rotational diffusion, and intermediate-range hydrodynamic interactions. Vortex structures found in simulations of the theory agree with recent measurements in Bacillus subtilis suspensions. Moreover, our approach yields an effective viscosity enhancement (reduction), as reported experimentally for puller (pusher) microorganisms

Stationarity, soft ergodicity, and entropy in relativistic systems

Recent molecular dynamics simulations show that a dilute relativistic gas equilibrates to a Juettner velocity distribution if ensemble velocities are measured simultaneously in the observer frame. The analysis of relativistic Brownian motion processes, on the other hand, implies that stationary one-particle distributions can differ depending on the underlying time-parameterizations. Using molecular dynamics simulations, we demonstrate how this relativistic phenomenon can be understood within a deterministic model system. We show that, depending on the time-parameterization, one can distinguish different types of soft ergodicity on the level of the one-particle distributions. Our analysis further reveals a close connection between time parameters and entropy in special relativity. A combination of different time-parameterizations can potentially be useful in simulations that combine molecular dynamics algorithms with randomized particle creation, annihilation, or decay processes.Comment: 4 page

The Genetic Basis of Delayed Puberty.

The genetic control of puberty remains an important but mostly unanswered question. Late pubertal timing affects over 2% of adolescents and is associated with adverse health outcomes including short stature, reduced bone mineral density, and compromised psychosocial health. Self-limited delayed puberty (DP) is a highly heritable trait, which often segregates in an autosomal dominant pattern; however, its neuroendocrine pathophysiology and genetic regulation remain unclear. Some insights into the genetic mutations that lead to familial DP have come from sequencing genes known to cause gonadotropin-releasing hormone (GnRH) deficiency, most recently via next-generation sequencing, and others from large-scale genome-wide association studies in the general population. Investigation of the genetic control of DP is complicated by the fact that this trait is not rare and that the phenotype is likely to represent a final common pathway, with a variety of different pathogenic mechanisms affecting the release of the puberty "brake." These include abnormalities of GnRH neuronal development and function, GnRH receptor and luteinizing hormone/follicle-stimulating hormone abnormalities, metabolic and energy homeostatic derangements, and transcriptional regulation of the hypothalamic-pituitary-gonadal axis. Thus, genetic control of pubertal timing can range from early fetal life via development of the GnRH network to those factors directly influencing the puberty brake during mid-childhood

Intraocular Nematodiasis in a Llama (\u3cem\u3eLama glama\u3c/em\u3e)

This report describes a unique case of presumed migration of Parelaphastrongylus tenuis through the spinal cord into the eye of a llama where it survived and matured within the ocular environment. Blindness of the eye was most likely attributable to migration of the parasite through the central nervous tissue. Résumé Infestation par les nématodes intraoculaire chez un lama (Lama glama). Ce rapport décrit un cas unique de migration présumée de Parelaphastrongylus tenuis dans la colonne vertébrale jusque dans l’œil d’un lama où il a survécu et est parvenu à maturité dans l’environnement oculaire. La cécité de l’œil a été le plus probablement attribuable à la migration du parasite dans les tissus du système nerveux central. (Traduit par Isabelle Vallières

Management of hypogonadism from birth to adolescence.

Management of patients with hypogonadism is dependent on the underlying cause. Whilst functional hypogonadism presenting as delayed puberty in adolescence is relatively common, permanent hypogonadism presenting in infancy or adolescence is unusual. The main differential diagnoses of delayed puberty include self-limited delayed puberty (DP), idiopathic hypogonadotropic hypogonadism (IHH) and hypergonadotropic hypogonadism. Treatment of self-limited DP involves expectant observation or short courses of low dose sex steroid supplementation. More complex and involved management is required in permanent hypogonadism to achieve both development of secondary sexual characteristics and to maximize the potential for fertility. This review will cover the options for management involving sex steroid or gonadotropin therapy, with discussion of benefits, limitations and specific considerations of the different treatment options

ENDO-ERN expert opinion on the differential diagnosis of pubertal delay.

The differential diagnoses of pubertal delay include hypergonadotropic hypogonadism and congenital hypogonadotropic hypogonadism (CHH), as well as constitutional delay of growth and puberty (CDGP). Distinguishing between CDGP and CHH may be challenging, and the scientific community has been struggling to develop diagnostic tests that allow an accurate differential diagnosis. Indeed, an adequate and timely management is critical in order to enable optimal clinical and psychosocial outcomes of the different forms of pubertal delays. In this review, we provide an updated insight on the differential diagnoses of pubertal delay, including the available tests, their meanings and accuracy, as well as some clues to effectively orientate towards either constitutional pubertal delay or pathologic CHH and hypergonadotropic hypogonadism