Exact Fermi coordinates for a class of spacetimes

We find exact Fermi coordinates for timelike geodesic observers for a class of spacetimes that includes anti-de Sitter spacetime, de Sitter spacetime, the constant density interior Schwarzschild spacetime with positive, zero, and negative cosmological constant, and the Einstein static universe. Maximal charts for Fermi coordinates are discussed.Comment: 15 page

Unsteady flow around a Rectangular Cylinder

This paper describes an investigation into the unsteady flow behaviour around a rectangular cylinder using particle image velocimetry (PIV). Instantaneous and average velocity fields were obtained from PIV images. Analysis of the structures observed in the instantaneous velocity fields reveals the presence of small scale (Kelvin-Helmholtz) vortex structures in the shear layer that separates at the leading edge of the rectangular cylinder, and evidence of von Karman vortex shedding was observed in the wake region

Ustekinumab in the therapy of chronic plaque psoriasis

Psoriasis is a chronic inflammatory disorder characterized by T cell dysregulation and a chronic inflammatory infiltrate within the epidermis. Several cytokines play an important role in the pathogenesis of psoriasis, including interleukin-12 (IL-12) and IL-23. These cytokines act via induction of pro-inflammatory cytokines which promote chronic inflammation and auto-reactivity. Ustekinumab is a fully human monoclonal antibody against the common p40 subunit of IL-12 and IL-23. Two randomized, double-blind, placebo-controlled trials of ustekinumab have demonstrated significant and prolonged efficacy in the treatment of plaque psoriasis. Adverse events were generally similar across treatment and control groups. Studies are ongoing to assess the long term safety and efficacy profiles of ustekinumab

Disruptive Mood Dysregulation Disorder

Disruptive mood dysregulation disorder (DMDD), a new diagnosis in The Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM–5; American Psychiatric Association [APA], 2013), is characterized by chronic, severe persistent irritability in children and adolescents. DMDD was added to the DSM-5, in part, to address concerns about potential over-diagnosis and overtreatment of bipolar disorder in children (APA, 2013). DMDD characterizes behavior that is considered outside of the normal range of childhood behavior; the major features of this disorder include severe recurrent temper outbursts manifested verbally (e.g., verbal rages) and/or behaviorally (e.g., physical aggression toward people or property) that are grossly out of proportion in intensity or duration to the situation or provocation (APA, 2013)

Disruptive Mood Dysregulation Disorder

Disruptive mood dysregulation disorder (DMDD), a new diagnosis in The Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM–5; American Psychiatric Association [APA], 2013), is characterized by chronic, severe persistent irritability in children and adolescents. DMDD was added to the DSM-5, in part, to address concerns about potential over-diagnosis and overtreatment of bipolar disorder in children (APA, 2013). DMDD characterizes behavior that is considered outside of the normal range of childhood behavior; the major features of this disorder include severe recurrent temper outbursts manifested verbally (e.g., verbal rages) and/or behaviorally (e.g., physical aggression toward people or property) that are grossly out of proportion in intensity or duration to the situation or provocation (APA, 2013)

The sectional curvature remains positive when taking quotients by certain nonfree actions

We study some cases when the sectional curvature remains positive under the taking of quotients by certain nonfree isometric actions of Lie groups. We consider the actions of the groups $S^1$ and $S^3$ such that the quotient space can be endowed with a smooth structure using the fibrations $S^3/S^1{\simeq}S^2$ and $S^7/S^3\simeq S^4$. We prove that the quotient space carries a metric of positive sectional curvature, provided that the original metric has positive sectional curvature on all 2-planes orthogonal to the orbits of the action.Comment: 26 pages, 1 figure. Changed the spelling of the author's nam

Financial objectives and satisfaction with life: A mixed-method study in surf lifestyle entrepreneurs

Tourism lifestyle entrepreneurs (TLEs) have introduced an innovation in business management based on the region, community, environmental sustainability, and extra financial factors. This type of entrepreneur allows the development of regions by attracting investment and presenting innovative products/services and is an important aid to the local economy. Based on the importance of TLEs, this study aims to explore factors influencing satisfaction with life as a key ingredient to attracting surf TLE. For this purpose, priority was given to obtaining primary data through a sequential approach of mixed methods, first with a quantitative study using survey data of 109 surf TLEs, followed by in-depth interviews. The results show that a good contact network and a strong link to a place influence satisfaction with life in a positive way. As a result, the moderating effect of financial objectives on these relationships alerts destination decision-makers about different entrepreneurial approaches regarding surf businessman attraction. This study makes an important contribution by providing empirical evidence regarding the ongoing discussion about financial vs. non-financial objectives for this type of entrepreneur, showing that both are important for their decision-making process. These results provide valuable insights for several industry stakeholders, namely funders (for grant approval), policymakers (alerting that these entrepreneurs should be addressed considering non-financial objectives), and entrepreneurs (alerting to goal definition patterns).info:eu-repo/semantics/publishedVersio

Effects of short and extended fasting periods and cattle breed on glycogenolysis, sarcomere shortening and Warner-Bratzler shear force

The effects of short (three hours) and extended (24 hours) feed withdrawal periods and three cattle breeds on muscle energy metabolism, sarcomere length, and meat quality were investigated. Brahman (Br), Nguni (Ng), and Simmental (Sm) bulls were subjected to ante-mortem feed withdrawal of three hours (Br3, n = 10; Ng3, n = 10; and Sm3, n = 10) or 24 hours (Br24, n = 10; Ng24, n = 10; and Sm24, n = 10). M. longissimus was used as the reference muscle for sampling. pH, and temperature was recorded at 1, 2, 3, 6, 9, and 24 hours post mortem. Samples for energy metabolites were removed at 3, 6, 9 and 24 hours post mortem. Glycogen, glucose-6-phosphate and creatine phosphate concentration were determined at each time interval as glycosyl units after hydrolysis. Samples to determine sarcomere length were removed at one and three days post mortem. Homogenates of the samples were placed under a 31,000 magnification microscope and sarcomere lengths were measured. Warner-Bratzler shear force (WBSF) was measured with an Instron meter at 1, 7 and 14 days post mortem. Glycogen was lower for Br24 and Ng24. There were no differences in glucose-6-phosphate, rate of creatine phosphate decline, average sarcomere length, or WBSF for Br24 and Ng24 compared with Br3 and Ng3. There were no differences for WBSF between Br3, Ng3 and Sm3. Glycogen concentration was higher for Sm24 compared with Sm3; glucose-6-phosphate was lower for Sm24 compared with Sm3; and the rate of creatine phosphate decline was higher for Sm24 compared with Sm3. Average sarcomere length was shorter and WBSF was higher for Sm24 compared with Sm3. The effect of prolonged ante-mortem feed withdrawal on tenderness is breed specific. Warner-Bratzler shear force was affected significantly by an extended feed withdrawal period in Simmental cattle only.Keywords: Acidification, creatine phosphate depletion, fasting, hypometabolism, meat tendernes

A note on the computation of geometrically defined relative velocities

We discuss some aspects about the computation of kinematic, spectroscopic, Fermi and astrometric relative velocities that are geometrically defined in general relativity. Mainly, we state that kinematic and spectroscopic relative velocities only depend on the 4-velocities of the observer and the test particle, unlike Fermi and astrometric relative velocities, that also depend on the acceleration of the observer and the corresponding relative position of the test particle, but only at the event of observation and not around it, as it would be deduced, in principle, from the definition of these velocities. Finally, we propose an open problem in general relativity that consists on finding intrinsic expressions for Fermi and astrometric relative velocities avoiding terms that involve the evolution of the relative position of the test particle. For this purpose, the proofs given in this paper can serve as inspiration.Comment: 8 pages, 2 figure

3D Simulations of MHD Jet Propagation Through Uniform and Stratified External Environments

We present a set of high-resolution 3D MHD simulations of steady light, supersonic jets, exploring the influence of jet Mach number and the ambient medium on jet propagation and energy deposition over long distances. The results are compared to simple self-similar scaling relations for the morphological evolution of jet-driven structures and to previously published 2D simulations. For this study we simulated the propagation of light jets with internal Mach numbers 3 and 12 to lengths exceeding 100 initial jet radii in both uniform and stratified atmospheres. The propagating jets asymptotically deposit approximately half of their energy flux as thermal energy in the ambient atmosphere, almost independent of jet Mach number or the external density gradient. Nearly one-quarter of the jet total energy flux goes directly into dissipative heating of the ICM, supporting arguments for effective feedback from AGNs to cluster media. The remaining energy resides primarily in the jet and cocoon structures. Despite having different shock distributions and magnetic field features, global trends in energy flow are similar among the different models. As expected the jets advance more rapidly through stratified atmospheres than uniform environments. The asymptotic head velocity in King-type atmospheres shows little or no deceleration. This contrasts with jets in uniform media with heads that are slowed as they propagate. This suggests that the energy deposited by jets of a given length and power depends strongly on the structure of the ambient medium. While our low-Mach jets are more easily disrupted, their cocoons obey evolutionary scaling relations similar to the high-Mach jets.Comment: Accepted in ApJ, 32 pages, 18 figures, animations available from: http://www.msi.umn.edu/Projects/twj/newsite/projects/radiojets/movies