Hasil untuk "Literature (General)"

Magdalena van den Berg, W. Wendel-Vos, M. Poppel et al.

E. Berner, M. Graber

D. Bhatkhande, V. G. Pangarkar, A. Beenackers

A. Carmeli

F. Solis, R. Wets

J. V. Bradley

J. Stewart Black, M. Mendenhall

J. Simón, L. Verde, R. Jimenez

We develop a formalism to characterize the shape and the redshift evolution of the dark energy potential. Our formalism makes use of quantities similar to the horizon-flow parameters in inflation and is general enough that can deal with multiscalar quintessence scenarios, exotic matter components, and higher-order curvature corrections to General Relativity. We show how the shape of the dark energy potential can be recovered nonparametrically using this formalism and we present approximations analogous to the ones relevant to slow-roll inflation. Since presently available data do not allow a nonparametric and exact reconstruction of the potential, we consider a general parametric description. This reconstruction can also be used in other approaches followed in the literature (e.g., the reconstruction of the redshift evolution of the dark energy equation of state $w(z)$). Using observations of passively evolving galaxies and supernova data we derive constraints on the dark energy potential shape in the redshift range $0.1lzl1.8$. Our findings show that at the $1\ensuremath{\sigma}$ level the potential is consistent with being constant, although at the same level of confidence variations cannot be excluded with current data. We forecast constraints achievable with future data from the Atacama Cosmology Telescope.

T. Vogelsang

M. Pigliucci, C. Murren, C. Schlichting

N. P. Padhy

S. Valentine, J. Shipherd

Transgender and gender non-conforming (TGNC) populations, including those who do not identify with gender binary constructs (man or woman) are increasingly recognized in health care settings. Research on the health of TGNC people is growing, and disparities are often noted. In this review, we examine 77 studies published between January 1, 1997 and March 22, 2017 which reported mental health outcomes in TGNC populations to (a) characterize what is known about mental health outcomes and (b) describe what gaps persist in this literature. In general, depressive symptoms, suicidality, interpersonal trauma exposure, substance use disorders, anxiety, and general distress have been consistently elevated among TGNC adults. We also used the minority stress model as a framework for summarizing existing literature. While no studies included all elements of the Minority Stress Model, this summary gives an overview of which studies have looked at each element. Findings suggest that TGNC people are exposed to a variety of social stressors, including stigma, discrimination, and bias events that contribute to mental health problems. Social support, community connectedness, and effective coping strategies appear beneficial. We argue that routine collection of gender identity data could advance our understanding mental health risk and resilience factors among TGNC populations.

S. Bahamonde, K. Dialektopoulos, C. Escamilla-Rivera et al.

Teleparallel gravity (TG) has significantly increased in popularity in recent decades, bringing attention to Einstein’s other theory of gravity. In this Review, we give a comprehensive introduction to how teleparallel geometry is developed as a gauge theory of translations together with all the other properties of gauge field theory. This relates the geometry to the broader metric-affine approach to forming gravitational theories where we describe a systematic way of constructing consistent teleparallel theories that respect certain physical conditions such as local Lorentz invariance. We first use TG to formulate a teleparallel equivalent of general relativity (GR) which is dynamically equivalent to GR but which may have different behaviors for other scenarios, such as quantum gravity. After setting this foundation, we describe the plethora of modified teleparallel theories of gravity that have been proposed in the literature. We attempt to connect them together into general classes of covariant gravitational theories. Of particular interest, we highlight the recent proposal of a teleparallel analogue of Horndeski gravity which offers the possibility of reviving all of the regular Horndeski contributions. In the second part of the Review, we first survey works in teleparallel astrophysics literature where we focus on the open questions in this regime of physics. We then discuss the cosmological consequences for the various formulations of TG. We do this at background level by exploring works using various approaches ranging from dynamical systems to Noether symmetries, and more. Naturally, we then discuss perturbation theory, firstly by giving a concise approach in which this can be applied in TG theories and then apply it to a number of important theories in the literature. Finally, we examine works in observational and precision cosmology across the plethora of proposal theories. This is done using some of the latest observations and is used to tackle cosmological tensions which may be alleviated in teleparallel cosmology. We also introduce a number of recent works in the application of machine learning to gravity, we do this through deep learning and Gaussian processes, together with discussions about other approaches in the literature.

S. Adami, Xiangyu Y. Hu, N. Adams

T. Beehr, J. E. Newman

R. Bouncken, J. Gast, S. Kraus et al.

Stephen J. Redding, M. Turner

Melissa A. Polusny, V. Follette

L. Dickinson

Shuai Wang, Lihong Cui

For a (molecular) graph $G$ and any real number $α\ne 0$ , the zero-order general Randić index , denote by $^0R_α$, is defined by the following equation: \begin{align*} {^0R_α} (G) =\sum_{v\in G}d_G (v) ^α (α\in \mathbb{R}-\left\{0\right\}) . \end{align*} In this paper, we use this index to give sufficient conditions for a graph $G$ to satisfy the Hamiltonian (or $k$-Hamiltonian) property, and show that none of these conditions can be dropped. Finally we give similar results for the case when $G$ is a balanced bipartite graph.