Why are very short times so long and very long times so short in elastic waves?

In a first study of thermoelastic waves, such as on the textbook of Landau and Lifshitz, one might at first glance understand that when the given period is very short, waves are isentropic because heat conduction does not set in, while if the given period is very long waves are isothermal because there is enough time for thermalization to be thoroughly accomplished. When one pursues the study of these waves further, by the mathematical inspection of the complete thermoelastic wave equation he finds that if the period is very short, much shorter than a characteristic time of the material, the wave is isothermal, while if it is very long, much longer than the characteristic time, the wave is isentropic. One also learns that this fact is supported by experiments: at low frequencies the elastic waves are isentropic, while they are isothermal when the frequencies are so high that can be attained in few cases. The authors show that there is no contradiction between the first glance understanding and the mathematical treatment of the elastic wave equation: for thermal effects very long periods are so short and very short periods are so long.Comment: 7 pages, submitted to European Journal of Physic

Rapid Star Formation in the Presence of Active Galactic Nuclei

Recent observations reveal galaxies in the early Universe (2<z<6.4) with large reservoirs of molecular gas and extreme star formation rates. For a very large range of sources, a tight relationship exists between star formation rate and the luminosity of the HCN J=1-0 spectral line, but sources at redshifts of z~2 and beyond do not follow this trend. The deficit in HCN is conventionally explained by an excess of infrared (IR) radiation due to active galactic nuclei (AGN). We show in this letter not only that the presence of AGN cannot account for the excess of IR over molecular luminosity, but also that the observed abundance of HCN is in fact consistent with a population of stars forming from near-primordial gas.Comment: 4 pages, 1 figure. Accepted by the Astrophysical Journal Letter

Lifting the Fog: The Problem of Antipsychotic Drug Use in Nursing Facilities

With the rapid increase in the elder population nationwide, the problem of excessive dependence on risky antipsychotic drug treatment for dementia-related behavioral problems in nursing facilities must be addressed. At the federal level, the over-prescription of antipsychotics to the elderly in nursing homes is addressed first by regulation specific to nursing facilities, such as the Federal Nursing Home Reform Amendments (FNHRA), a part of the Ombudsman Budget Reconciliation Act of 1987 (OBRA ’87) as well as through the Centers for Medicare and Medicaid Services (CMS) guidelines. Secondarily, the Food and Drug Administration (FDA) has authority to issue black box warnings and regulation pertaining to off-label drug use for antipsychotics used to treat behavioral problems associated with dementia, a use that has not been approved by the FDA. Additionally, under state common law, these problems are addressed under the informed consent and right to refuse treatment doctrines. Despite the extensive multi-tiered body of law addressing this issue, no coherent and effective system has yet been devised to effectively protect patient rights. This paper suggests solutions to system failures via multi-faceted changes at federal and state levels in order to make the available framework more coherent and facilitate a shift to a nonpharmacologic treatment emphasis in the future

A three-dimensional symmetry result for a phase transition equation in the genuinely nonlocal regime

We consider bounded solutions of the nonlocal Allen-Cahn equation (-\Delta)^s u=u-u^3\qquad{\mbox{ in }}{\mathbb{R}}^3, under the monotonicity condition $\partial_{x_3}u>0$ and in the genuinely nonlocal regime in which~$s\in\left(0,\frac12\right)$. Under the limit assumptions \lim_{x_n\to-\infty} u(x',x_n)=-1\quad{\mbox{ and }}\quad \lim_{x_n\to+\infty} u(x',x_n)=1, it has been recently shown that~$u$ is necessarily $1$D, i.e. it depends only on one Euclidean variable. The goal of this paper is to obtain a similar result without assuming such limit conditions. This type of results can be seen as nonlocal counterparts of the celebrated conjecture formulated by Ennio De Giorgi

The statistical distribution of magnetic field strength in G-band bright points

G-band bright points are small-sized features characterized by high photometric contrast. Theoretical investigations indicate that these features have associated magnetic field strengths between 1-2 kG. Results from observations instead lead to contradictory results, indicating magnetic fields of only kG strength in some and including hG strengths in others. In order to understand the differences between measurements reported in the literature, and to reconcile them with results from theory, we analyze the distribution of magnetic field strength of G-band bright features identified on synthetic images of the solar photosphere, and its sensitivity to observational and methodological effects. We investigate the dependence of magnetic field strength distributions of G-band bright points identified in 3D magnetohydrodynamic simulations on feature selection method, data sampling, alignment and spatial resolution. The distribution of magnetic field strength of G-band bright features shows two peaks, one at about 1.5 kG and one below 1 hG. The former corresponds to magnetic features,the second mostly to bright granules. Peaks at several hG are obtained only on spatially degraded or misalligned data. Simulations show that magnetic G-band bright points have typically associated field strengths of few kG. Field strengths in the hG range can result from observational effects, thus explaining the discrepancies presented in the literature. Our results also indicate that outcomes from spectro-polarimetric inversions with imposed unit filling-factor should be employed with great caution