Back reaction of a long range force on a Friedmann-Robertson-Walker background

It is possible that there may exist long-range forces in addition to gravity. In this paper we construct a simple model for such a force based on exchange of a massless scalar field and analyze its effect on the evolution of a homogeneous Friedmann-Robertson-Walker cosmology. The presence of such an interaction leads to an equation of state characterized by positive pressure and to resonant particle production similar to that observed in preheating scenarios.Comment: 14 pages, 6 color Postscript figures, LaTe

Observational evidence for self-interacting cold dark matter

Cosmological models with cold dark matter composed of weakly interacting particles predict overly dense cores in the centers of galaxies and clusters and an overly large number of halos within the Local Group compared to actual observations. We propose that the conflict can be resolved if the cold dark matter particles are self-interacting with a large scattering cross-section but negligible annihilation or dissipation. In this scenario, astronomical observations may enable us to study dark matter properties that are inaccessible in the laboratoryComment: 4 pages, no figures; added references, pedagogical improvements, to appear in PR

Employment-Precipitated Heart Attacks: A Few Legal Issues in Establishing Compensability

I. [Introduction] II. Compensability … A. In General … B. Usual versus Unusual Exertion in Heart Attack Cases … 1. Legislative Development … 2. Judicial Analogy III. Rules of Evidence … A. In General … B. Spontaneous Declarations and Res Gestae … C. The “State of Mind” Exception … D. “Habit” … E. The “Dead Man’s Statute” … F. Uniform Business Records as Evidence Ac

Employment-Precipitated Heart Attacks: A Few Legal Issues in Establishing Compensability

I. [Introduction] II. Compensability … A. In General … B. Usual versus Unusual Exertion in Heart Attack Cases … 1. Legislative Development … 2. Judicial Analogy III. Rules of Evidence … A. In General … B. Spontaneous Declarations and Res Gestae … C. The “State of Mind” Exception … D. “Habit” … E. The “Dead Man’s Statute” … F. Uniform Business Records as Evidence Ac

Linear and non-linear perturbations in dark energy models

I review the linear and second-order perturbation theory in dark energy models with explicit interaction to matter in view of applications to N-body simulations and non-linear phenomena. Several new or generalized results are obtained: the general equations for the linear perturbation growth; an analytical expression for the bias induced by a species-dependent interaction; the Yukawa correction to the gravitational potential due to dark energy interaction; the second-order perturbation equations in coupled dark energy and their Newtonian limit. I also show that a density-dependent effective dark energy mass arises if the dark energy coupling is varying.Comment: 12 pages, submitted to Phys. Rev; v2: added a ref. and corrected a typ

Defense styles from the perspective of affective neuroscience

To our knowledge, no study has been carried out to observe which subcortical basic affective systems are related to which defense styles. Such a perspective may have the potential to reveal how defenses may interact with subcortical primary emotional systems (PES) and how they contribute to affect regulation. We aimed to analyze the relationship of immature, neurotic, and mature defenses with basic subcortical affects (CARE, PLAY, SEEK, SADNESS, FEAR, ANGER) within an affective neuroscientific perspective. In addition, we sought to explore the effect of psychiatric disorders in relation to PES and defenses, and observe gender effects, if any. The sample consisted of 703 university students, recruited online. The materials included the Turkish translations of the Affective Neuroscience Personality Scales (ANPS) and the Defense Style Questionnaire (DSQ). The correlations between ANPS and DSQ showed that the immature defenses increase as all negative emotions increase, whereas mature defenses increase as all positive emotions (except CARE) increase and all negative affects decrease (except ANGER). On the other hand, as neurotic defenses increase, CARE, FEAR and SADNESS simultaneously increase. Subjects who reported the presence of psychiatric disorders also reported higher FEAR, SADNESS, ANGER accompanied by higher immature defenses. Finally, male subjects reported higher immature defenses, whereas the females reported higher neurotic defenses, accompanied by higher CARE, SEEK, SADNESS, FEAR, and slightly lower PLAY. Investigating defenses through the lens of affective neuroscience offers the opportunity to link the abstract concept of defenses to increasingly well-understood neurobiology

The Chromatin Modifier MSK1/2 Suppresses Endocrine Cell Fates during Mouse Pancreatic Development

Type I diabetes is caused by loss of insulin-secreting beta cells. To identify novel, pharmacologically-targetable histone-modifying proteins that enhance beta cell production from pancreatic progenitors, we performed a screen for histone modifications induced by signal transduction pathways at key pancreatic genes. The screen led us to investigate the temporal dynamics of ser-28 phosphorylated histone H3 (H3S28ph) and its upstream kinases, MSK1 and MSK2 (MSK1/2). H3S28ph and MSK1/2 were enriched at the key endocrine and acinar promoters in E12.5 multipotent pancreatic progenitors. Pharmacological inhibition of MSK1/2 in embryonic pancreatic explants promoted the specification of endocrine fates, including the beta-cell lineage, while depleting acinar fates. Germline knockout of both Msk isoforms caused enhancement of alpha cells and a reduction in acinar differentiation, while monoallelic loss of Msk1 promoted beta cell mass. Our screen of chromatin state dynamics can be applied to other developmental contexts to reveal new pathways and approaches to modulate cell fates

The developmental regulator Pax6 is essential for maintenance of islet cell function in the adult mouse pancreas

The transcription factor Pax6 is a developmental regulator with a crucial role in development of the eye, brain, and olfactory system. Pax6 is also required for correct development of the endocrine pancreas and specification of hormone producing endocrine cell types. Glucagon-producing cells are almost completely lost in Pax6-null embryos, and insulin-expressing beta and somatostatin-expressing delta cells are reduced. While the developmental role of Pax6 is well-established, investigation of a further role for Pax6 in the maintenance of adult pancreatic function is normally precluded due to neonatal lethality of Pax6-null mice. Here a tamoxifen-inducible ubiquitous Cre transgene was used to inactivate Pax6 at 6 months of age in a conditional mouse model to assess the effect of losing Pax6 function in adulthood. The effect on glucose homeostasis and the expression of key islet cell markers was measured. Homozygous Pax6 deletion mice, but not controls, presented with all the symptoms of classical diabetes leading to severe weight loss requiring termination of the experiment five weeks after first tamoxifen administration. Immunohistochemical analysis of the pancreata revealed almost complete loss of Pax6 and much reduced expression of insulin, glucagon, and somatostatin. Several other markers of islet cell function were also affected. Notably, strong upregulation in the number of ghrelin-expressing endocrine cells was observed. These findings demonstrate that Pax6 is essential for adult maintenance of glucose homeostasis and function of the endocrine pancreas

Electromechanical Behavior of Al/Al2_{2}O3_{3} Multilayers on Flexible Substrates: Insights from In Situ Film Stress and Resistance Measurements

A series of Al and Al/Al$_{2}$O$_{3}$ thin-film multilayer structures on flexible polymer substrates are fabricated with a unique deposition chamber combining magnetron sputtering (Al) and atomic layer deposition (ALD, Al$_{2}$O$_{3}$, nominal thickness 2.4–9.4 nm) without breaking vacuum and thoroughly characterized using transmission electron microscopy (TEM). The electromechanical behavior of the multilayers and Al reference films is investigated in tension with in situ X-ray diffraction (XRD) and four-point probe resistance measurements. All films exhibit excellent interfacial adhesion, with no delamination in the investigated strain range (12%). For the first time, an adhesion-promoting naturally forming amorphous interlayer is confirmed for thin films sputter deposited onto polymers under laboratory conditions. The evolution of Al film stresses and electrical resistance reveal changes in the deformation behavior as a function of oxide thickness. Strengthening of Al is observed with increasing oxide thickness. Significant embrittlement can be avoided for oxide layer thicknesses ≤2.4 nm