Energy distributions of symbiotic novae

The IRAS low-resolution spectra of three recent symbiotic novae (HM Sge. V1016 Cyg, and RR Tel) are fitted with a dust continuum radiative transfer model. We find that the dust shells are detached from the photosphere and that the sizes of the inner radii are correlated with times since outburst. An analysis of the IUE spectra of HM Sge at different epochs suggests that the strength of the 2200 Å feature is decreasing with time and the grains responsible for the feature are probably formed in the white dwarf ejecta. A complete accounting of the entire energy budget from radio to X-ray shows that most of the energy is emitted by the cool component in the infrared, and a significant fraction of the flux of the hot component is escaping in the far-ultraviolet. The density-bounded nature of the circumstellar gas nebulae could be the result of a bipolar geometry of the nebulae. Unlike classical novae, the optical outburst of symbiotic novae is due to the ionization of the preexisting envelope of the cool component and is not the result of a sudden ejection by the hot component.published_or_final_versio

On the formation of carbon stars

We present an integrated model of asymptotic giant branch (AGB) evolution, using empirical formulae to allow for nuclear shell burning in the core, the dredge-up of heavy elements to the envelope, and mass loss from the surface. We emphasize the role of mass loss in the formation of carbon stars. The formation rate of carbon stars, for an assumed constant dredge-up every thermal pulse, is critically dependent on the mass-loss formula. The observed luminosity distribution of AGB stars, the initial-final mass relationship, the oxygen-rich-to-carbon-rich star ratio, and the total population of carbon stars can be reproduced by a new proposed mass-loss formula based upon the Reimers formula but with an initial mass- [M *(0)] dependent η value (η = 0.2875[M *(0) 2-10.6M *(0) + 10.2]). For initial masses between 1.25 and 8 M ⊙, our best fit is obtained with a carbon dredge-up of ∼6% by mass each thermal pulse. The observed data are, however, not consistent with any of the "superwind" mass-loss formulae where most of the envelope mass is removed near the end of the AGB. We also find that carbon stars primarily descended from a low-mass (<3 M ⊙) population, and high-mass (3-8 M ⊙) stars remain oxygen-rich for most of their AGB lifetime.published_or_final_versio

Reconstructing particle masses from pairs of decay chains

A method is proposed for determining the masses of the new particles N,X,Y,Z in collider events containing a pair of effectively identical decay chains Z to Y+jet, Y to X+l_1, X to N+l_2, where l_1, l_2 are opposite-sign same-flavour charged leptons and N is invisible. By first determining the upper edge of the dilepton invariant mass spectrum, we reduce the problem to a curve for each event in the 3-dimensional space of mass-squared differences. The region through which most curves pass then determines the unknown masses. A statistical approach is applied to take account of mismeasurement of jet and missing momenta. The method is easily visualized and rather robust against combinatorial ambiguities and finite detector resolution. It can be successful even for small event samples, since it makes full use of the kinematical information from every event.Comment: 12 pages, 5 figure

Cosmological Adaptive Mesh Refinement

We describe a grid-based numerical method for 3D hydrodynamic cosmological simulations which is adaptive in space and time and combines the best features of higher order--accurate Godunov schemes for Eulerian hydrodynamics with adaptive particle--mesh methods for collisionless particles. The basis for our method is the structured adaptive mesh refinement (AMR) algorithm of Berger & Collela (1989), which we have extended to cosmological hydro + N-body simulations. The resulting multiscale hybrid method is a powerful alternative to particle-based methods in current use. The choices we have made in constructing this algorithm are discussed, and its performance on the Zeldovich pancake test problem is given. We present a sample application of our method to the problem of first structure formation. We have achieved a spatial dynamic range $L_{box}/\Delta x > 250,000$ in a 3D multispecies gas + dark matter calculation, which is sufficient to resolve the formation of primordial protostellar cloud cores starting from linear matter fluctuations in an expanding FRW universe.Comment: 14 pages, 3 figures (incl. one large color PS) to appear in "Numerical Astrophysics 1998", eds. S. Miyama & K. Tomisaka, Tokyo, March 10-13, 199

Baryons in the warm-hot intergalactic medium

Approximately 30%-40% of all baryons in the present-day universe reside in a warm-hot intergalactic medium (WHIM), with temperatures in the range 105 \u3c T \u3c 107 K. This is a generic prediction from six hydrodynamic simulations of currently favored structure formation models having a wide variety of numerical methods, input physics, volumes, and spatial resolutions. Most of these warm-hot baryons reside in diffuse large-scale structures with a median overdensity around 10-30, not in virialized objects such as galaxy groups or galactic halos. The evolution of the WHIM is primarily driven by shock heating from gravitational perturbations breaking on mildly nonlinear, nonequilibrium structures such as filaments. Supernova feedback energy and radiative cooling play lesser roles in its evolution. WHIM gas may be consistent with observations of the 0.25 keV X-ray background without being significantly heated by nongravitational processes because the emitting gas is very diffuse. Our results confirm and extend previous work by Cen & Ostriker and Davé et al

Gender Differences in Emergency Department (ED) Patient Mechanical Fall Risk and Openness to Communication with Providers

Gender Differences in Emergency Department (ED) Patient Mechanical Fall Risk and Openness to Communication with Providers Bryan G Kane, MD, Michael C Nguyen MD, Robert D Barraco, MD MPH, Brian Stello MD, Arnold Goldberg MD, Clare M Lenhart, PhD MPH, Bernadette G Porter BA ,Anita Kurt PhD, RN, Marna Rayl Greenberg DO, MPH Objectives: The CDC reports that among older adults (≥65), falls are the leading cause of injury-related death and rates of fall-related fractures among older women are more than twice those for men. We set out to determine ED patient perceptions (analyzed by gender) about their personal fall risk compared to their actual risk and their comfort level in discussing their fall history or a home safety plan with their healthcare provider. Methods: After IRB approval, a convenience sample of ED patients (50 years or older) was surveyed at a suburban Level 1 Trauma center with an annual ED census of approximately 75,000. The survey included demographics, the Falls Efficacy Scale (FES), and questions about fall risk. The FES is a validated survey measuring concern of falling. Analysis included descriptive statistics and assessment of fall risk and fear of falling by gender using chi-square and t-tests as indicated. Significance was set at 0.05. Results: Of the 150 surveys collected, 149 indicated gender and were included in this analysis. Fifty-five percent of the sample was female (n=82); 45% (n=67) were male. Most (98%) were Caucasian and 22% reported living alone. There was not a difference in the mean age of female participants 69.79 years (SD=12.08) vs. males 68.06 (SD=10.36; p=0.355). See Table 1 for distribution of reported fall risk factors between genders. Collectively, these variables resulted in a mean risk of falling score of 3.37(SD=1.62) out of 9. On average, female participants had a significantly higher objective risk of falling than did male participants (3.65 vs. 3.02 p=0.018). Similarly, females also reported greater fear of falling than did males (FES score 12.33 vs. 9.62; p=0.005). Significantly more females (41.5%) than males (23.9%, p=0.037) reported having fallen in the past year. Of the 50 participants reporting past-year falls, only 19 (12 female and 7 male, p=0.793) sought treatment. The correlation between actual fall risk and fear of falling were greater among females (p The majority of patients (76.4%) were willing to speak to a provider about their fall risk. No significant difference was noted in willingness to discuss this topic with a provider based on gender (p=0.619), objective fall risk (p=0.145) or FES score (p=0.986). Similarly, many respondents indicated a willing to discuss a home safety evaluation with a provider (58.1%) and responses did not vary significantly by gender (p=.140), objective fall risk (p=0.168) or FES score (p=.584). Conclusion: In this study, female ED patients reported a greater fear of falling, had a significantly higher objective risk of falling, and had a higher correlation between their perceived risk and actual risk of falling than did males. The majority of both genders were amenable to discussing their fall risk and a home safety evaluation with their provider

Modified CAGE as a Screening Tool for Mechanical Fall Risk Assessment: A Pilot Survey

Modified CAGE as a Screening Tool for Mechanical Fall Risk Assessment: A Pilot Survey Marna Rayl Greenberg DO, MPH, Michael C Nguyen MD, Bernadette G Porter BA,Robert DBarraco, MD MPH, Brian Stello MD, Arnold Goldberg MD, Clare M Lenhart, PhD MPH,Anita Kurt PhD, RN, Bryan G Kane, MD Background: Falls in the elderly cause serious injury. The literature does not hold answers to patient perceptions about their personal fall risk, their comfort level in discussing their fall history, or a home safety plan with their healthcare provider. Existing risk-assessing tools may be prohibitive in the Emergency Department due to their length and complexity. Objective: We piloted a modified CAGE screen (Fig1) to identify adults at risk for falls. Methods: At a community health event, a convenience sample ofparticipants (50 years or older) was surveyed. The survey included demographics, the Falls Efficacy Scale (FES), the modified CAGEand questions about fall risk.The FES is a validated, but longer, survey metric for comparison. A modified CAGE score greater than or equal to 1 was considered positive. Analysis included descriptive statistics and modified CAGE groups were compared by gender, fall risk and history with chi-square. Results: One hundred sevensubjects (66.4%female, 32.7% male) with a mean age of 66 (SD7.9)participated; 98 (91.6%)were Caucasian. Twenty (18.7%) lived alone,43 (40.2%) had a cat or dog, and 91 (85%) had stairs at home. Six (5.6%) reported using assistive devices, 2 (1.9%) at-risk alcohol use; 9 (8.4%)taking blood thinners, 50 (46.7%) taking blood pressure medications, and 22 (20.6%) one or more medications that could make them drowsy. Thirty-threesubjects(30.8%) reported having fallen in the past year; only13 (39.4% of those fallen)sought treatment. Collectively, these variables resulted in a mean risk of falling score of 2.49 (SD=1.36) out of 9. Eleven (31.4%)femalesand27 (38.0%)malesrecorded ≥1 positive responses on the modified CAGE.A modified CAGE positive responsewas significantly greater among those with past-year falls (51.5%) than those without (29.7%), p=0.031.A positive modified CAGE screen was also associated with a higher mean FES score (10.82 v7.83, p More females than males reported past year falls (36.6% vs. 17.1%, p=0.04) yet no difference in fall risk was noted between genders (4.44 vs. 4.26, p=0.506). The proportion of modified CAGE positive participants did not vary between females and males (38% vs. 31%, p=0.505). Of those whoscreened positive on the modified CAGE, 36 (92.3%) reported comfort in speaking to their healthcare provider about their fall risk and 26 (66.7%) in having a home safety evaluation. Conclusions: In this pilot, a positive modified CAGE is associated with both higher FES scores and a willingness to discuss fall risk with a health care provider. The modifiedCAGE may be a usefulbrief screening tool to detect fall risk in adults. Further studies to determine the extent of its utility in an Emergency Department should be considered

Calmodulin-like proteins localized to the conoid regulate motility and cell invasion by Toxoplasma gondii

Toxoplasma gondii contains an expanded number of calmodulin (CaM)-like proteins whose functions are poorly understood. Using a combination of CRISPR/Cas9-mediated gene editing and a plant-like auxin-induced degron (AID) system, we examined the roles of three apically localized CaMs. CaM1 and CaM2 were individually dispensable, but loss of both resulted in a synthetic lethal phenotype. CaM3 was refractory to deletion, suggesting it is essential. Consistent with this prediction auxin-induced degradation of CaM3 blocked growth. Phenotypic analysis revealed that all three CaMs contribute to parasite motility, invasion, and egress from host cells, and that they act downstream of microneme and rhoptry secretion. Super-resolution microscopy localized all three CaMs to the conoid where they overlap with myosin H (MyoH), a motor protein that is required for invasion. Biotinylation using BirA fusions with the CaMs labeled a number of apical proteins including MyoH and its light chain MLC7, suggesting they may interact. Consistent with this hypothesis, disruption of MyoH led to degradation of CaM3, or redistribution of CaM1 and CaM2. Collectively, our findings suggest these CaMs may interact with MyoH to control motility and cell invasion