Modeling the RXTE light curve of η\eta Carinae from a 3-D SPH simulation of its binary wind collision

The very massive star system $\eta$ Carinae exhibits regular 5.54-year (2024-day) period disruptive events in wavebands ranging from the radio to X-ray. There is a growing consensus that these events likely stem from periastron passage of an (as yet) unseen companion in a highly eccentric ($\epsilon \sim 0.9$) orbit. This paper presents three-dimensional (3-D) Smoothed Particle Hydrodynamics (SPH) simulations of the orbital variation of the binary wind-wind collision, and applies these to modeling the X-ray light curve observed by the Rossi X-ray Timing Explorer (RXTE). By providing a global 3-D model of the phase variation of the density of the interacting winds, the simulations allow computation of the associated variation in X-ray absorption, presumed here to originate from near the apex of the wind-wind interaction cone. We find that the observed RXTE light curve can be readily fit if the observer's line of sight is within this cone along the general direction of apastron. Specifically, the data are well fit by an assumed inclination $i = 45^{\circ}$ for the orbit's polar axis, which is thus consistent with orbital angular momentum being along the inferred polar axis of the Homunculus nebula. The fits also constrain the position angle $\phi$ that an orbital-plane projection makes with the apastron side of the semi-major axis, strongly excluding positions $\phi < 9^{\circ}$ along or to the retrograde side of the axis, with the best fit position given by $\phi = 27^{\circ}$. Overall the results demonstrate the utility of a fully 3-D dynamical model for constraining the geometric and physical properties of this complex colliding-wind binary system.Comment: 5 pages, 4 figures, accepted to MNRAS Letter

Acute complete heart block in dogs

A study has been conducted immediately and up to 18 days after the surgical production of complete heart block in dogs. Immediately after surgery cardiac output, coronary flow, and mean arterial pressure were reduced in rough proportion to the degree of bradycardia. In time, these measures began to return toward preoperative levels. Paralleling the diminished left ventricular work was a diminished left ventricular oxygen consumption with little consequent change in myocardial efficiency. Small rises were detected in central venous pressure. At autopsy, the only unequivocal abnormality was myocardial hypertrophy which became measurable between 2 and 18 days after operation

On the changes in the physical properties of the ionized region around the Weigelt structures in Eta Carinae over the 5.54-yr spectroscopic cycle

We present HST/STIS observations and analysis of two prominent nebular structures around the central source of Eta Carinae, the knots C and D. The former is brighter than the latter for emission lines from intermediate or high ionization potential ions. The brightness of lines from intermediate and high ionization potential ions significantly decreases at phases around periastron. We do not see conspicuous changes in the brightness of lines from low ionization potential (<13.6 eV) that the total extinction towards the Weigelt structures is that the total extinction towards the Weigelt structures is AsubV =2/0. that the total extinction towards the Weigelt structures is AV = 2.0. Weigelt C and D are characterized by an electron density of that the total extinction towards the Weigelt structures is AV = 2.0. Weigelt C and D are characterized by an electron density of 10exp6.9 cm-3 that does not significantly change throughout the orbital cycle. The electron temperature varies from 5500 K (around periastron) to 7200 K (around apastron). The relative changes in the brightness of He I lines are well reproduced by the variations in the electron temperature alone. We found that, at phases around periastron, the electron temperature seems to be higher for Weigelt C than that of D. The Weigelt structures are located close to the Homunculus equatorial plane, at a distance of about 1240 AU from the central source. From the analysis of proper motion and age, the Weigelt complex can be associated with the equatorial structure called the Butterfly Nebula surrounding the central binary system.Comment: 19 pages, 18 figure

Dementia management: an occupational therapy home-based intervention for caregivers.

This paper describes an occupational therapy intervention designed for family caregivers of persons with dementia. The intervention, based on the framework of a competence-environmental press model and the principle of collaboration, was implemented during 5 home visits. Each visit was designed to build caregiving skills through collaboration in identifying problem areas, developing and implementing environmental strategies, and modifying management approaches. A case vignette illustrates the therapeutic process and outcomes. The theoretical rationale and structure of the intervention and innovative documentation for evaluation of the theoretic process are also presented

Justice for the Forgotten: Saving the Women of Darfur

Since 2003, Darfur has lost nearly half of its six million inhabitants. As many as 500,000 people have been slaughtered, 2.2 million have been displaced, and an untold number have been savagely raped—all victims of a brutal five-year genocide orchestrated by the Sudanese government. The women of Darfur have borne the brunt of the violence: constantly targeted for rape, left physically and emotionally broken. The use of rape as a weapon of war should have shocked the conscience of the world, but we have failed to act, and instead have allowed the women of Darfur to be victimized repeatedly. This note argues that the international community must take two steps to save the women of Darfur: (1) continue criminal prosecutions of those responsible for the genocide in the International Criminal Court and (2) immediately undertake humanitarian solutions in Darfur, including aid disbursement, reparations, military intervention, and political pressure. It is only by combining legal and restorative solutions that the forgotten women of Darfur will truly receive justice

Gender differences in dementia management plans of spousal caregivers: implications for occupational therapy.

Occupational therapists treating older people with Alzheimer disease know that they must also consider the others who are affected by the disease, the informal caregivers. Intervention is most effective when it enables both the impaired person and the primary caregiver to manage the secondary symptoms of dementia. Unfortunately, little is understood about how caregivers approach and carry out their tasks and about why male and female caregivers respond differently to their caregiving role in terms of depression, burden, stress, and substance abuse. This paper discusses the effects of gender on dementia management plans of spousal caregivers. Husbands and wives have different approaches to caregiving; each approach has consequences. Male caregivers adopt a task-oriented approach to their duties and carry out their activities in a linear fashion; female caregivers use a parent-child approach and nest activities inside one another in a constant stream of work. Two cases are presented to illustrate gender differences in dementia management plans. Implications for occupational therapy include suggestions for supporting men and women in their caregiving role, modulating the negative consequences of caregiving, and conducting research to demonstrate the efficacy of an occupational therapy approach