Observations of Hierarchical Solar-Type Multiple Star Systems

Twenty multiple stellar systems with solar-type primaries were observed at high angular resolution using the PALM-3000 adaptive optics system at the 5 m Hale telescope. The goal was to complement the knowledge of hierarchical multiplicity in the solar neighborhood by confirming recent discoveries by the visible Robo-AO system with new near-infrared observations with PALM-3000. The physical status of most, but not all, of the new pairs is confirmed by photometry in the Ks band and new positional measurements. In addition, we resolved for the first time five close sub-systems: the known astrometric binary in HIP 17129AB, companions to the primaries of HIP 33555, and HIP 118213, and the companions to the secondaries in HIP 25300 and HIP 101430. We place the components on a color-magnitude diagram and discuss each multiple system individually.Comment: Accepted to Astronomical Journa

Direct measurements of the polarization of terrestrial kilometric radiation from Voyagers 1 and 2

Terrestrial radiation measurements obtained with planetary radio astronomy experiments on Voyager-1 and 2 during the early portions of each flight show the signals to be predominantly left-hand circularly polarized. Since these emissions were most probably generated above the Northern Hemisphere auroral zone, it is concluded that the radiation is emitted primarily in the extraordinary mode

Phylogenetic structure of vertebrate communities across the A ustralian arid zone

Aim To understand the relative importance of ecological and historical factors in structuring terrestrial vertebrate assemblages across the A ustralian arid zone, and to contrast patterns of community phylogenetic structure at a continental scale. Location Australia. Methods We present evidence from six lineages of terrestrial vertebrates (five lizard clades and one clade of marsupial mice) that have diversified in arid and semi‐arid A ustralia across 37 biogeographical regions. Measures of within‐lineage community phylogenetic structure and species turnover were computed to examine how patterns differ across the continent and between taxonomic groups. These results were examined in relation to climatic and historical factors, which are thought to play a role in community phylogenetic structure. Analyses using a novel sliding‐window approach confirm the generality of processes structuring the assemblages of the A ustralian arid zone at different spatial scales. Results Phylogenetic structure differed greatly across taxonomic groups. Although these lineages have radiated within the same biome – the A ustralian arid zone – they exhibit markedly different community structure at the regional and local levels. Neither current climatic factors nor historical habitat stability resulted in a uniform response across communities. Rather, historical and biogeographical aspects of community composition (i.e. local lineage persistence and diversification histories) appeared to be more important in explaining the variation in phylogenetic structure. While arid‐zone assemblages show an overall tendency towards phylogenetic clustering, this pattern was less pronounced at finer spatial scales. Main conclusions By focusing within different taxonomic groups and between those groups within regions, we show that although the vertebrate lineages we examined exhibited high diversity and low turnover across the arid zone, the underlying phylogenetic structure differs between regions and taxonomic groups, suggesting that taxon‐specific histories are more important than habitat stability in determining patterns of phylogenetic community relatedness.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98265/1/jbi12077.pd

Tropospheric gravity waves observed by three closely spaced ST radars

Clear-air radar experiments were carried out on the southern coast of France during the (ALPEX) Alpine experiment program vertically directed stratosphere-troposphere-radars were set up with spacings of about 5 to 6 km. The temporal and spectral characteristics of the vertical velocity fluctuations were examined. The horizontal and vertical properties of gravity waves in the lower atmosphere were analyzed. The techniques used and the first results from this wave study are described

Know the Star, Know the Planet. III. Discovery of Late-Type Companions to Two Exoplanet Host Stars

We discuss two multiple star systems that host known exoplanets: HD 2638 and 30 Ari B. Adaptive optics imagery revealed an additional stellar companion to both stars. We collected multi-epoch images of the systems with Robo-AO and the PALM-3000 adaptive optics systems at Palomar Observatory and provide relative photometry and astrometry. The astrometry indicates that the companions share common proper motion with their respective primaries. Both of the new companions have projected separations less than 30 AU from the exoplanet host star. Using the projected separations to compute orbital periods of the new stellar companions, HD 2638 has a period of 130 yrs and 30 Ari B has a period of 80 years. Previous studies have shown that the true period is most likely within a factor of three of these estimated values. The additional component to the 30 Ari makes it the second confirmed quadruple system known to host an exoplanet. HD 2638 hosts a hot Jupiter and the discovery of a new companion strengthens the connection between hot Jupiters and binary stars. We place the systems on a color-magnitude diagram and derive masses for the companions which turn out to be roughly 0.5 solar mass stars.Comment: Accepted to Astronomical Journal, 16 pages, 5 Figure

Hypoxia-Inducible Factor-1α Restricts the Anabolic Actions of Parathyroid Hormone

The hypoxia inducible factors (Hifs) are evolutionarily conserved transcriptional factors that control homeostatic responses to low oxygen. In developing bone, Hif-1 generated signals induce angiogenesis necessary for osteoblast specification, but in mature bone, loss of Hif-1 in osteoblasts resulted in a more rapid accumulation of bone. These findings suggested that Hif-1 exerts distinct developmental functions and acts as a negative regulator of bone formation. To investigate the function of Hif-1α in osteoanabolic signaling, we assessed the effect of Hif-1α loss-of-function on bone formation in response to intermittent parathyroid hormone (PTH). Mice lacking Hif-1α in osteoblasts and osteocytes form more bone in response to PTH, likely through a larger increase in osteoblast activity and increased sensitivity to the hormone. Consistent with this effect, exposure of primary mouse osteoblasts to PTH resulted in the rapid induction of Hif-1α protein levels via a post-transcriptional mechanism. The enhanced anabolic response appears to result from the removal of Hif-1α-mediated suppression of β-catenin transcriptional activity. Together, these data indicate that Hif-1α functions in the mature skeleton to restrict osteoanabolic signaling. The availability of pharmacological agents that reduce Hif-1α function suggests the value in further exploration of this pathway to optimize the therapeutic benefits of PTH

Voyager spacecraft radio observations of Jupiter: Initial cruise results

Jupiter's low-frequency radio emission were detected by the planetary radio astronomy instruments onboard the two Voyager spacecraft. The emission is surprisingly similar in morphology but opposite in polarization to the high-frequency Jovian radio noise that were observed with ground-based telescopes for more than two decades. Several possible explanations for the behavior of the low-frequency emission are examined, but none of them is completely satisfactory

Current Surgical Management of Hidradenitis Suppurativa: A Systematic Review and Meta-Analysis

BACKGROUND: Hidradenitis suppurativa (HS) is a chronic dermatologic condition that often necessitates surgical treatment. Surgical approaches vary substantially with little data on efficacy and safety. OBJECTIVE: Summarize the literature on HS surgery with regards to patient characteristics, surgical approaches, and study quality. Compare postsurgical recurrence rates with a meta-analysis. METHODS: PubMed, Embase, and Scopus were searched for studies on surgical HS management published after 2004. A random effects meta-analysis of recurrence rates was performed on eligible studies. RESULTS: Of 715 identified studies, 59 were included in the review and 33 in the meta-analysis. Twenty-two studies of wide excision had the lowest pooled recurrence rate at 8% (95% confidence interval [CI] 2%-16%); local excision had the highest at 34% (95% CI 24%-44%). For studies of wide/radical excision, flap repair had the lowest pooled recurrence rate at 0% (95% CI 0%-4%); delayed primary closure had the highest at 38% (95% CI 20%-59%). CONCLUSIONS: Wide excision and flap-based reconstruction are associated with a lower postsurgical HS recurrence, although this must be balanced against potentially higher morbidity of extensive procedures. Heterogeneity and methodological limitations of the evidence limit the ability to make a strong conclusion about the relative recurrence rates associated with surgical techniques. REGISTRATION: PROSPERO ID: CRD42020159948