Resolving the Controversy Over the Core Radius of 47 Tucanae (NGC 104)

This paper investigates the discrepancy between recent measurements of the density profile of the globular cluster 47 Tuc that have used HST data sets. Guhathakurta et al. (1992) used pre-refurbishment WFPC1 V-band images to derive r_c = 23" +/- 2". Calzetti et al. (1993) suggested that the density profile is a superposition of two King profiles (r_c = 8" and r_c = 25") based on U-band FOC images. De Marchi et al. (1996) used deep WFPC1 U-band images to derive r_c = 12" +/- 2". Differences in the adopted cluster centers are not the cause of the discrepancy. Our independent analysis of the data used by De Marchi et al. reaches the following conclusions: (1) De Marchi et al.'s r_c ~ 12" value is spuriously low, a result of radially-varying bias in the star counts in a magnitude limited sample -- photometric errors and a steeply rising stellar luminosity function cause more stars to scatter across the limiting magnitude into the sample than out of it, especially near the cluster center where crowding effects are most severe. (2) Changing the limiting magnitude to the main sequence turnoff, away from the steep part of the luminosity function, partially alleviates the problem and results in r_c = 18". (3) Combining such a limiting magnitude with accurate photometry derived from PSF fitting, instead of the less accurate aperture photometry employed by De Marchi et al., results in a reliable measurement of the density profile which is well fit by r_c = 22" +/- 2". Archival WFPC2 data are used to derive a star list with a higher degree of completeness, greater photometric accuracy, and wider areal coverage than the WFPC1 and FOC data sets; the WFPC2-based density profile supports the above conclusions, yielding r_c = 24" +/- 1.9".Comment: 22 pages, 5 figures, 1 table; accepted for publication in PASP; see http://www.ucolick.org/~raja/hgg.tar.gz for full-resolution figure

Genome sequences of 15 Gardnerella vaginalis strains isolated from the vaginas of women with and without bacterial vaginosis

Gardnerella vaginalis is a predominant species in bacterial vaginosis, a dysbiosis of the vagina that is associated with adverse health outcomes, including preterm birth. Here, we present the draft genome sequences of 15 Gardnerella vaginalis strains (now available through BEI Resources) isolated from women with and without bacterial vaginosis

Kinematic Comparison of Dolphin Kicking Performed in a Prone and Supine Body Position

Underwater dolphin kicking has become an essential element in competitive swimming but little research has been performed to provide an understanding of this movement. PURPOSE: To examine hip and knee kinematics of prone and supine dolphin kicking as they relate to speed. METHODS: Six collegiate swimmers (1.77±0.07 m, 72.4±7.6 kg, 19.8±1.0 yrs) experienced with dolphin kicking completed six 10 m maximal effort underwater kicking trials; three trials in a prone position and three trials in a supine position. An underwater camera was calibrated using a projective scaling technique and subsequently used to record each trial at 60 Hz. Twelve body landmarks were digitized from the video recordings to determine whole body center of mass location and hip and knee joint angles. Data were filtered using a fourth order Butterworth low-pass digital filter with cutoff frequencies individually determined for each coordinate or each landmark. Linear velocity of the center of mass was computed using the first central difference method. Hip and knee joint ranges of motion (ROM) were compared between body positions using a 2x2 (joint x body position) repeated measures ANOVA. Kick rate (KR) and horizontal velocity of the center of mass were compared between body positions using a two-tailed dependent t-test. RESULTS: Neither horizontal velocity (t(4)=0.308, p=0.774) nor kicking rate (t(4)=0.371, p=0.730) were different between body positions (Table 1). ROM was significantly greater in the knee than the hip (F(1,4)=110.967, p 2=0.965). ROM was not affected by body position (F(1,4)=1.068, p=0.36, 2=0.211). ROM did not interact between joint and body position (F(1,4)=1.461, p=0.818, 2=0.015). CONCLUSION: Despite some recent suggestions that a supine dolphin kick may be more effective than a prone dolphin kick, no kinematic difference were observed in this sample of swimmers. Table 1. Dolphin Kicking Kinematics. PRONE SUPINE KNEE ROM (degrees) 69.7±4.5 73.6.7±6.7 HIP ROM (degrees) 37.7±8.3 40.5±9.0 HORIZONTAL VELOCITY (m/s) 1.82±1.13 1.80±1.04 KICK RATE (kicks/min) 135.0±71.9 136.4±67.

Schumann\u27s Dichterliebe: A Revelation of a Great Composer\u27s Life and Passion

From a young age, German composer Robert Schumann’s passions for music, drama, and literature were evident. Through personal tragedies and an uncertain career path, these talents guided Schumann into a successful career in composition. Childhood interests in literature and the influence of German author Jean Paul Richter had a profound effect on Schumann’s compositional style. His view that music was the most effective aesthetic vehicle for expression was combined with Jean Paul’s definition of Romanticism to create a philosophy of music Schumann would come to live by. In the face of poverty, commercial failure, and artistic frustration with piano composition, Schumann took up a new compositional medium in the form of songwriting. The resulting Year of the Song in 1840 produced over 120 vocal compositions, including the Dichterliebe song cycle. This masterpiece of German Lieder and Romantic song cycle tradition is widely regarded as one of the greatest ever written. Dichterliebe, song settings of poems by German poet Heinrich Heine, displays Schumann’s distinctive ability to set text to music. His use of tonal relationships utilizes modality to guide the narrative along its trajectory. His affinity for romantic irony is evident in the creative ways in which he expresses this literary concept musically. Finally, Schumann’s unique talents in creating complex piano arrangements to provide musical imagery and aesthetic atmosphere set this work apart from others of the time. This paper will explore the life of Robert Schumann, how his passions, interests, and heartaches shaped his compositional style, examine his techniques and unique approach to text painting, and discuss considerations for the performer of Dichterliebe

Analytical and experimental study of FRP honeycomb sandwich panels with sinusoidal core

Fiber reinforced plastic (FRP) composite materials and structures have been increasingly used in highway bridge applications. Recent applications have demonstrated that FRP honeycomb sandwich panels with sinusoidal core can be effectively and economically used for highway bridge deck systems. In this study, analytical and experimental characterizations are presented for a FRP honeycomb panel with sinusoidal core geometry in the plane and extending vertically between face laminates. To verify the accuracy of the a closed-form solution, several honeycomb sandwich beams with sinusoidal core waves either in the longitudinal or transverse directions are tested in bending and torsion. Also, a deck panel is tested under both symmetric and asymmetric patch loading. Finite element models are further developed to simulate the actual sandwich geometry and also to simplify the structure as an equivalent three-layer laminate. The explicit and FE predictions are compared with experimental results. The present analysis and characterization procedures can be used in design applications and optimizations of honeycomb structures

Miniature exoplanet radial velocity array I: design, commissioning, and early photometric results

The MINiature Exoplanet Radial Velocity Array (MINERVA) is a US-based observational facility dedicated to the discovery and characterization of exoplanets around a nearby sample of bright stars. MINERVA employs a robotic array of four 0.7 m telescopes outfitted for both high-resolution spec- troscopy and photometry, and is designed for completely autonomous operation. The primary science program is a dedicated radial velocity survey and the secondary science objective is to obtain high precision transit light curves. The modular design of the facility and the flexibility of our hardware allows for both science programs to be pursued simultaneously, while the robotic control software provides a robust and efficient means to carry out nightly observations. In this article, we describe the design of MINERVA including major hardware components, software, and science goals. The telescopes and photometry cameras are characterized at our test facility on the Caltech campus in Pasadena, CA, and their on-sky performance is validated. New observations from our test facility demonstrate sub-mmag photometric precision of one of our radial velocity survey targets, and we present new transit observations and fits of WASP-52b—a known hot-Jupiter with an inflated radius and misaligned orbit. The process of relocating the MINERVA hardware to its final destination at the Fred Lawrence Whipple Observatory in southern Arizona has begun, and science operations are expected to commence within 2015

Formation, Survival, and Detectability of Planets Beyond 100 AU

Direct imaging searches have begun to detect planetary and brown dwarf companions and to place constraints on the presence of giant planets at large separations from their host star. This work helps to motivate such planet searches by predicting a population of young giant planets that could be detectable by direct imaging campaigns. Both the classical core accretion and the gravitational instability model for planet formation are hard-pressed to form long-period planets in situ. Here, we show that dynamical instabilities among planetary systems that originally formed multiple giant planets much closer to the host star could produce a population of giant planets at large (~100 AU - 100000 AU) separations. We estimate the limits within which these planets may survive, quantify the efficiency of gravitational scattering into both stable and unstable wide orbits, and demonstrate that population analyses must take into account the age of the system. We predict that planet scattering creates a population of detectable giant planets on wide orbits that decreases in number on timescales of ~10 Myr. We demonstrate that several members of such populations should be detectable with current technology, quantify the prospects for future instruments, and suggest how they could place interesting constraints on planet formation models.Comment: 13 pages (emulateapj format), 10 figures, accepted for publication in Ap

Hsp70 Oligomerization Is Mediated by an Interaction between the Interdomain Linker and the Substrate-Binding Domain

Oligomerization in the heat shock protein (Hsp) 70 family has been extensively documented both in vitro and in vivo, although the mechanism, the identity of the specific protein regions involved and the physiological relevance of this process are still unclear. We have studied the oligomeric properties of a series of human Hsp70 variants by means of nanoelectrospray ionization mass spectrometry, optical spectroscopy and quantitative size exclusion chromatography. Our results show that Hsp70 oligomerization takes place through a specific interaction between the interdomain linker of one molecule and the substrate-binding domain of a different molecule, generating dimers and higher-order oligomers. We have found that substrate binding shifts the oligomerization equilibrium towards the accumulation of functional monomeric protein, probably by sequestering the helical lid sub-domain needed to stabilize the chaperone: substrate complex. Taken together, these findings suggest a possible role of chaperone oligomerization as a mechanism for regulating the availability of the active monomeric form of the chaperone and for the control of substrate binding and release. © 2013 Aprile et al.FAA was recipient of a graduate fellowship from the Italian Ministry of Education, University and Research. AD is grateful for support from Murray Edwards College, Cambridge, through a Junior Research Fellowship. FS is a Sir Henry Wellcome Fellow. CR acknowledges financial support by the Spanish Ministry of Health according to the 'Plan Nacional de I+D+I 2008-2011', through ISCIII with cofunding by FEDER (CP10/00527). JLPB is a Royal Society University Research Fellow. FAA and PT are grateful for support from Regione Lombardia (NEDD and >Network Tecnologico integrato per lo studio proteomico e trascrittomico di malattie neurodegenerative correlate a deposizioni di amiloidi>). CMD acknowledges support from BBSRC (BB/E019927/1), the Wellcome Trust (094425/Z/10/Z), the European Commission (project LSHM-CT-2006-037525). NC acknowledges support from Human Frontiers Science Program (HFSP) through a Long-term Fellowship (LT000795/2009).Peer Reviewe