Revealing the Young Starburst in Haro 3 with Radio and Infrared Imaging

The Wolf-Rayet galaxy Haro 3 (Mrk 35, NGC 3353) was observed at the near-IR and radio wavelengths as part of ongoing program to study the earliest stages of starbursts. These observations confirm that the current episode of star formation is dominated by a single region (region A). While there are knots of recent (~10 Myr) star formation outside of region A, the sources of ionizing radiation as observed in both radio and Br-gamma observations are almost exclusively associated with region A. The derived ionizing flux implies a star formation rate of ~0.6 solar masses per year localized within a radius of ~0.1 kpc. A comparison with observations from HST indicates that one or more of the star clusters in region A are optically obscured. The star clusters in region A have ages at least as young as ~5 Myr, and possibly as young as ~0.1 Myr. The star cluster that appears to be the youngest also exhibits a near-IR excess in its colors, possibly indicating natal dust in very close proximity to the ionizing stars. The difference between optical- and radio-determined ionizing fluxes as well as the near-IR colors indicate an average extinction value of A_V ~2.5 in region A. The total stellar mass associated with the current starburst in region A is inferred from both the near-IR and radio observations to be ~10^6 solar masses. The other main stellar concentrations observed in the near-IR (Regions B1 and B2) are somewhat older than region A, with ages ~8-10 Myr, and the near-IR observations indicate they have stellar masses of ~8x10^4 and ~2x10^4 solar masses, respectively.Comment: 17 pages, 3 figures, to appear in AJ August 200

CORRELATION BETWEEN IMPAIRMENT AND MOTOR PERFORMANCE DURING REACHING TASKS IN SUBJECTS WITH SPASTIC HEMIPARESIS

Objective: The main purposes of this study were to examine, in subjects with chronic hemiparesis following a stroke: (i) the correlations between tests of muscle tone, stiffness, spasticity, paresis and co-contraction, and (ii) the correlations of these tests and measurements of impairment to upper extremity motor performance. Design: Prospective, cross-sectional, correlation matrix using sample of convenience. Subjects: Thirteen subjects with chronic hemiparesis secondary to a cerebrovascular accident (stroke) were tested. Methods: Subjects were assessed using the Fugl-Meyer Upper Extremity Motor Assessment, modified Ashworth scale, deep tendon reflexes, and muscle characteristics that included quantification of muscle stiffness, paresis and co-contraction during a voluntary reaching task and during passive movements. Surface electromyographic and myotonometric muscle stiffness data were obtained during movement trials. Results: Biceps and triceps brachii muscle paresis and excess biceps brachii co-contraction during voluntary reaching had the highest correlations to decreased motor performance. Muscle tone measurements did not have significant correlations to upper extremity performance. Conclusion: Paresis of elbow flexors and extensors and excess co-contraction of the biceps brachii during voluntary reaching appear to be most predictive of upper extremity motor performance. Results are discussed in relation to the specific challenges these findings pose for spastic paresis clinical management

Signatures of the Youngest Starbursts: Optically-thick Thermal Bremsstrahlung Radio Sources in Henize 2-10

VLA radio continuum imaging reveals compact (<8 pc) ~1 mJy radio sources in the central 5" starburst region of the blue compact galaxy Henize 2-10. We interpret these radio knots as extremely young, ultra-dense HII regions. We model their luminosities and spectral energy distributions, finding that they are consistent with unusually dense HII regions having electron densities, 1500 cm^-3 < n_e < 5000 cm^-3, and sizes of 3-8 pc. Since these H II regions are not visible in optical images, we propose that the radio data preferentially reveal the youngest, densest, and most highly obscured starforming events. Energy considerations imply that each of the five \HII regions contains ~750 O7V equivalent stars, greater than the number found in 30 Doradus in the LMC. The high densities imply an over-pressure compared to the typical interstellar medium so that such objects must be short-lived (<0.5 Myr expansion timescales). We conclude that the radio continuum maps reveal the very young (<0.5 Myr) precursors of ``super starclusters'' or ``proto globular clusters'' which are prominent at optical and UV wavelengths in He 2-10. If the ultra-dense HII regions are typical of those which we predict will be found in other starbursting systems, then super starclusters spend 15% of their lifetime in heavily-obscured environments, similar to Galactic ultra-compact HII regions. This body of work leads us to propose that massive extragalactic star clusters (i.e. proto globular clusters) with ages <10^6 yr may be most easily identified by finding compact radio sources with optically-thick thermal bremsstrahlung spectral signatures.Comment: AASTeX, 8 figures 2 included with psfig in text; other 6 in jpeg format; Postscript versions of figures may be found at http://zem.ucolick.org/chip/Research/young_clusters.html -- Accepted for publication in the Astrophysical Journa

Clusters of Extragalactic Ultra Compact HII Regions

We report on the detection of optically thick free-free radio sources in the galaxies M33, NGC 253, and NGC 6946 using data in the literature. We interpret these sources as being young, embedded star birth regions, which are likely to be clusters of ultracompact HII regions. All 35 of the sources presented in this article have positive radio spectral indices alpha>0 suggesting an optically thick thermal bremsstrahlung emission arising in the HII region surrounding hot stars. Energy requirements indicate a range of a several to >500 O7V star equivalents powering each HII region. Assuming a Salpeter IMF, this corresponds to integrated stellar masses of 0.1--60,000 Msun. For roughly half of the sources in our sample, there is no obvious optical counterpart, giving further support for their deeply embedded nature. Their luminosities and radio spectral energy distributions are consistent with HII regions having electron densities from 1500 cm^-3 to 15000 cm^-3 and radii of 1 - 7 pc. We suggest that the less luminous of these sources are extragalactic ultracompact HII region complexes, those of intermediate luminosity are similar to W49 in the Galaxy, while the brightest will be counterparts to 30 Doradus. These objects constitute the lower mass range of extragalactic ``ultradense HII regions'' which we argue are the youngest stages of massive star cluster formation yet observed. This sample is beginning to fill in the continuum of objects between small associations of ultracompact HII regions and the massive extragalactic clusters that may evolve into globular clusters.Comment: 37 pages, uses AASTeX; scheduled to appear in ApJ v. 559 October 2001. Full postscript version available from http://www.astro.wisc.edu/~chip/Papers/Johnson_Kobulnicky_etal_ApJ559.ps.g

Managing physical and mental health conditions: Consumer perspectives on integrated care

Despite the growing trend of integrating primary care and mental health services, little research has documented how consumers with severe mental illnesses (SMI) manage comorbid conditions or view integrated services. We sought to better understand how consumers perceive and manage both mental and physical health conditions and their views of integrated services. We conducted semi-structured interviews with consumers receiving primary care services integrated in a community mental health setting. Consumers described a range of strategies to deal with physical health conditions and generally viewed mental and physical health conditions as impacting one another. Consumers viewed integration of primary care and mental health services favorably, specifically its convenience, friendliness, and knowledge of providers, and collaboration between providers. Although integration was viewed positively, consumers with SMI may need a myriad of strategies and supports to both initiate and sustain lifestyle changes that address common physical health problems

Retired A Stars and Their Companions. III. Comparing the Mass-Period Distributions of Planets Around A-Type Stars and Sun-Like Stars

We present an analysis of ~5 years of Lick Observatory radial velocity measurements targeting a uniform sample of 31 intermediate-mass subgiants (1.5 < M*/Msun < 2.0) with the goal of measuring the occurrence rate of Jovian planets around (evolved) A-type stars and comparing the distributions of their orbital and physical characteristics to those of planets around Sun-like stars. We provide updated orbital solutions incorporating new radial velocity measurements for five known planet-hosting stars in our sample; uncertainties in the fitted parameters are assessed using a Markov Chain Monte Carlo method. The frequency of Jovian planets interior to 3 AU is 26 (+9,-8)%, which is significantly higher than the ~5-10% frequency observed around solar-mass stars. The median detection threshold for our sample includes minimum masses down to {0.2, 0.3, 0.5, 0.6, 1.3} MJup within {0.1, 0.3, 0.6, 1.0, 3.0} AU. To compare the properties of planets around intermediate-mass stars to those around solar-mass stars we synthesize a population of planets based on the parametric relationship dN ~ M^{alpha}P^{beta} dlnM dlnP, the observed planet frequency, and the detection limits we derived. We find that the values of alpha and beta for planets around solar-type stars from Cumming et al. fail to reproduce the observed properties of planets in our sample at the 4 sigma level, even when accounting for the different planet occurrence rates. Thus, the properties of planets around A stars are markedly different than those around Sun-like stars, suggesting that only a small (~ 50%) increase in stellar mass has a large influence on the formation and orbital evolution of planets.Comment: Accepted by the Astrophysical Journal; 15 pages, 15 figure

Expression of sterile-α and armadillo motif in rheumatoid arthritis monocytes correlates with TLR2 induced IL-1β and disease activity

Objective Cartilage and bone damage in rheumatoid arthritis (RA) are associated with elevated IL-1β. The effects of IL-1β can be reduced by biological therapies that target IL-1β or TNFα. However, the mechanisms responsible for increased IL-1β and the effect of anti-TNFα have not been fully elucidated. Recently, sterile-α and armadillo motif-containing protein (SARM) was identified as a negative regulator of toll-like receptor (TLR) induced IL-1β secretion through an interaction with the inflammasome. This study set out to investigate SARM during TLR induced IL-1β secretion in RA peripheral blood monocytes and in patients commencing anti-TNFα treatment. Methods Monocytes were isolated from RA patients and healthy controls; disease activity was measured by DAS28. IL-1β secretion was measured by ELISA following TLR1/2, TLR4 and TLR7/8 stimulation. The mRNA expression of SARM, IL-1β and the components of the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome were measured by quantitative PCR. SARM protein expression was measured by western blotting. Results TLR1/2 activation induced elevated IL-1β in RA monocytes compared with heathy controls (p= 0.0009), which negatively correlated with SARM expression (p = 0.0086). Lower SARM expression also correlated with higher disease activity (p = 0.0246). Additionally, patients responding to anti-TNFα treatment demonstrated a rapid upregulation of SARM, which was not observed in non-responders. Conclusion Together, these data highlight a potential contribution from SARM to RA pathophysiology where decreased SARM may lead to elevated IL-1β associated with RA pathogenesis. Furthermore, the data additionally present a potential mechanism by which TNFα blockade can modify IL-1β secretion

Retired A Stars and Their Companions VI. A Pair of Interacting Exoplanet Pairs Around the Subgiants 24 Sextanis and HD200964

We report radial velocity measurements of the G-type subgiants 24 Sextanis (=HD90043) and HD200964. Both are massive, evolved stars that exhibit periodic variations due to the presence of a pair of Jovian planets. Photometric monitoring with the T12 0.80m APT at Fairborn Observatory demonstrates both stars to be constant in brightness to <= 0.002 mag, thus strengthening the planetary interpretation of the radial velocity variations. 24 Sex b,c have orbital periods of 453.8 days and 883~days, corresponding to semimajor axes 1.333 AU and 2.08 AU, and minimum masses (Msini) 1.99 Mjup and 0.86 Mjup, assuming a stellar mass 1.54 Msun. HD200964 b,c have orbital periods of 613.8 days and 825 days, corresponding to semimajor axes 1.601 AU and 1.95 AU, and minimum masses 1.85 Mjup and 0.90 Mjup, assuming M* = 1.44 Msun. We also carry out dynamical simulations to properly account for gravitational interactions between the planets. Most, if not all, of the dynamically stable solutions include crossing orbits, suggesting that each system is locked in a mean motion resonance that prevents close encounters and provides long-term stability. The planets in the 24 Sex system likely have a period ratio near 2:1, while the HD200964 system is even more tightly packed with a period ratio close to 4:3. However, we caution that further radial velocity observations and more detailed dynamical modelling will be required to provide definitive and unique orbital solutions for both cases, and to determine whether the two systems are truly resonant.Comment: AJ accepte

Type Ia Supernova Rate Measurements To Redshift 2.5 From CANDELS: Searching For Prompt Explosions In The Early Universe

dThe Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope (HST) that surveyed a total area of -0.25 deg2 with -900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z 2.5. We classify -24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reaching for the first time beyond z =- 2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only -3 Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation ( 40 Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z > 1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20% of all SN Ia explosions-though further analysis and larger samples will be needed to examine that suggestion. Key words: infrared: general - supernovae:Astronom

Type Ia Supernova Distances at z > 1.5 from the Hubble Space Telescope Multi-Cycle Treasury Programs: The Early Expansion Rate

We present an analysis of 15 Type Ia supernovae (SNe Ia) at redshift z > 1 (9 at 1.5 < z < 2.3) recently discovered in the CANDELS and CLASH Multi-Cycle Treasury programs using WFC3 on the Hubble Space Telescope. We combine these SNe Ia with a new compilation of 1050 SNe Ia, jointly calibrated and corrected for simulated survey biases to produce accurate distance measurements. We present unbiased constraints on the expansion rate at six redshifts in the range 0.07 < z < 1.5 based only on this combined SN Ia sample. The added leverage of our new sample at z > 1.5 leads to a factor of ~3 improvement in the determination of the expansion rate at z = 1.5, reducing its uncertainty to ~20%, a measurement of H(z=1.5)/H0=2.67 (+0.83,-0.52). We then demonstrate that these six measurements alone provide a nearly identical characterization of dark energy as the full SN sample, making them an efficient compression of the SN Ia data. The new sample of SNe Ia at z > 1 usefully distinguishes between alternative cosmological models and unmodeled evolution of the SN Ia distance indicators, placing empirical limits on the latter. Finally, employing a realistic simulation of a potential WFIRST SN survey observing strategy, we forecast optimistic future constraints on the expansion rate from SNe Ia.Comment: 14 pages, 5 figures, 7 tables; submitted to Ap