Extraordinarily rapid proliferation of cultured muscle satellite cells from migratory birds

Migratory birds experience bouts of muscle growth and depletion as they prepare for, and undertake prolonged flight. Our studies of migratory bird muscle physiology in vitro led to the discovery that sanderling (Calidris alba) muscle satellite cells proliferate more rapidly than other normal cell lines. Here we determined the proliferation rate of muscle satellite cells isolated from five migratory species (sanderling; ruff, Calidris pugnax; western sandpiper, Calidris mauri; yellow-rumped warbler, Setophaga coronata; Swainson\u27s thrush, Catharus ustulatus) from two families (shorebirds and songbirds) and with different migratory strategies. Ruff and sanderling satellite cells exhibited rapid proliferation, with population doubling times of 9.3 ± 1.3 and 11.4 ± 2 h, whereas the remaining species\u27 cell doubling times were greater than or equal to 24 h. The results indicate that the rapid proliferation of satellite cells is not associated with total migration distance but may be related to flight bout duration and interact with lifespan

Towards Understanding Photodegradation Pathways in Lignins:The Role of Intramolecular Hydrogen Bonding in Excited States

The photoinduced dynamics of the lignin building blocks syringol, guaiacol, and phenol were studied using time-resolved ion yield spectroscopy and velocity map ion imaging. Following irradiation of syringol and guaiacol with a broad-band femtosecond ultraviolet laser pulse, a coherent superposition of out-of-plane OH torsion and/or OMe torsion/flapping motions is created in the first excited 1ππ* (S1) state, resulting in a vibrational wavepacket, which is probed by virtue of a dramatic nonplanar → planar geometry change upon photoionization from S1 to the ground state of the cation (D0). Any similar quantum beat pattern is absent in phenol. In syringol, the nonplanar geometry in S1 is pronounced enough to reduce the degree of intramolecular H bonding (between OH and OMe groups), enabling H atom elimination from the OH group. For guaiacol, H bonding is preserved after excitation, despite the nonplanar geometry in S1, and prevents O–H bond fission. This behavior affects the propensities for forming undesired phenoxyl radical sites in these three lignin chromophores and provides important insight into their relative “photostabilities” within the larger biopolymer

Assessment of cefazolin and cefuroxime tissue penetration by using a continuous intravenous infusion.

A continuous intravenous infusion was used to assess the tissue penetration of cefazolin (14 subjects) and cefuroxime (15 subjects) in orthopedic surgery patients. Subjects were randomly assigned to receive a continuous intravenous infusion of cefazolin (mean, 178.6 mg/h) orcefuroxime (mean, 330.0 mg/h) at a rate estimated to achieve a target steady-state total concentration of 50 micrograms/ml in serum. The infusion was initiated 12 to 14 h before surgery, and blood and muscle tissue samples were collected intraoperatively at the times of incision and wound closure. Although there was a significant difference between the free concentrations ofcefazolin (at incision, 9.3 micrograms/ml; at closure, 9.2 micrograms/ml) and cefuroxime in serum (at incision, 26.9 micrograms/ml; at closure, 31.8 micrograms/ml), there was no difference in the total concentrations in muscle at either surgical incision (cefazolin, 6.1 micrograms/g; cefuroxime, 5.6 micrograms/g) or wound closure (cefazolin, 7.7 micrograms/g; cefuroxime, 7.4 micrograms/g). There was a significant correlation between the pooled free serum and total muscle concentrations for cefazolin (P = 0.001); however, there was no correlation between these variables with the pooledcefuroxime data (P = 0.403). These findings indicate that the free drug concentration in serum alone is not consistently predictive of the total concentration of cephalosporin in muscle

Accurate Assignments of Excited-State Resonance Raman Spectra: A Benchmark Study Combining Experiment and Theory

This is an unofficial translation of an article that appeared in an ACS publication. ACS has not endorsed the content of this translation or the context of its use.Femtosecond stimulated Raman scattering (FSRS) probes the structural dynamics of molecules in electronically excited states by following the evolution of the vibrational spectrum. Interpreting the dynamics requires accurate assignments to connect the vibrational bands with specific nuclear motions of an excited molecule. However, the assignment of FSRS signals is often complicated by mode-specific resonance enhancement effects that are difficult to calculate for molecules in electronically excited states. We present benchmark results for a series of eight aryl-substituted thiophene derivatives to show that calculated off-resonance Raman spectra can be used to assign experimental bands on the basis of a comparison of structurally similar compounds and careful consideration of the resonance condition. Importantly, we show that direct comparison with the off-resonant calculations can lead to incorrect assignments of the experimental spectrum if the resonance condition is neglected. These results highlight the importance of resonance enhancement effects in assigning FSRS spectra

The Young and the Dustless: Interpreting Radio Observations of UltraViolet Luminous Galaxies

Ultraviolet Luminous Galaxies (UVLGs) have been identified as intensely star-forming, nearby galaxies. A subset of these, the supercompact UVLGs, are believed to be local analogs of high redshift Lyman Break Galaxies. Here we investigate the radio continuum properties of this important population for the first time. We have observed 42 supercompact UVLGs with the VLA, all of which have extensive coverage in the UV/optical by GALEX and SDSS. Our analysis includes comparison samples of multiwavelength data from the Spitzer First Look Survey and from the SDSS-Galex matched catalogs. In addition we have Spitzer MIPS data for 24 of our galaxies and find that they fall on the radio-FIR correlation of normal star-forming galaxies. We find that our galaxies have lower radio-to-UV ratios and lower Balmer decrements than other local galaxies with similar (high) star formation rates. Optical spectra show they have lower Dn(4000) and HdeltaA indices, higher Hbeta emission-line equivalents widths, and higher [OIII]5007/Hbeta emission-line ratios than normal star forming galaxies. Comparing these results to galaxy spectral evolution models we conclude that supercompact UVLGs are distinguished from normal star forming galaxies firstly by their high specific star formation rates. Moreover, compared to other types of galaxies with similar star formation rates, they have significantly less dust attenuation. In both regards they are similar to Lyman Break Galaxies. This suggests that the process that causes star formation in the supercompact UVLGs differs from other local star forming galaxies, but may be similar to Lyman Break Galaxies.Comment: 37 pages, 13 figures, accepted and scheduled to appear in ApJS December 2007 (GALEX Special Issue

Coronal hole boundaries at small scales: III. EIS and SUMER views

We report on the plasma properties of small-scale transient events identified in the quiet Sun, coronal holes and their boundaries. We use spectroscopic co-observations from SUMER/SoHO and EIS/Hinode combined with high cadence imaging data from XRT/Hinode. We measure Doppler shifts using single and multiple Gauss fits of transition region and coronal lines as well as electron densities and temperatures. We combine co-temporal imaging and spectroscopy to separate brightening expansions from plasma flows. The transient brightening events in coronal holes and their boundaries were found to be very dynamical producing high density outflows at large speeds. Most of these events represent X-ray jets from pre-existing or newly emerging coronal bright points at X-ray temperatures. The average electron density of the jets is logNe ~ 8.76 cm^-3 while in the flaring site it is logNe ~ 9.51 cm^-3. The jet temperatures reach a maximum of 2.5 MK but in the majority of the cases the temperatures do not exceed 1.6 MK. The footpoints of jets have temperatures of a maximum of 2.5 MK though in a single event scanned a minute after the flaring the measured temperature was 12 MK. The jets are produced by multiple microflaring in the transition region and corona. Chromospheric emission was only detected in their footpoints and was only associated with downflows. The Doppler shift measurements in the quiet Sun transient brightenings confirmed that these events do not produce jet-like phenomena. The plasma flows in these phenomena remain trapped in closed loops.Comment: 16 pages, accepted for publication in A&

The GALEX Ultraviolet Atlas of Nearby Galaxies

We present images, integrated photometry, and surface-brightness and color profiles for a total of 1034 nearby galaxies recently observed by the Galaxy Evolution Explorer (GALEX) satellite in its far-ultraviolet (FUV; λ_(eff) = 1516 Å) and near-ultraviolet (NUV; λ_(eff) = 2267 Å) bands. Our catalog of objects is derived primarily from the GALEX Nearby Galaxies Survey (NGS) supplemented by galaxies larger than 1' in diameter serendipitously found in these fields and in other GALEX exposures of similar of greater depth. The sample analyzed here adequately describes the distribution and full range of properties (luminosity, color, star formation rate [SFR]) of galaxies in the local universe. From the surface brightness profiles obtained we have computed asymptotic magnitudes, colors, and luminosities, along with the concentration indices C31 and C42. We have also morphologically classified the UV surface brightness profiles according to their shape. This data set has been complemented with archival optical, near-infrared, and far-infrared fluxes and colors. We find that the integrated (FUV − K) color provides robust discrimination between elliptical and spiral/irregular galaxies and also among spiral galaxies of different subtypes. Elliptical galaxies with brighter K-band luminosities (i.e., more massive) are redder in (NUV − K) color but bluer in (FUV − NUV) (a color sensitive to the presence of a strong UV upturn) than less massive ellipticals. In the case of the spiral/irregular galaxies our analysis shows the presence of a relatively tight correlation between the (FUV − NUV) color (or, equivalently, the slope of the UV spectrum, β) and the total infrared-to-UV ratio. The correlation found between (FUV − NUV) color and K-band luminosity (with lower luminosity objects being bluer than more luminous ones) can be explained as due to an increase in the dust content with galaxy luminosity. The images in this Atlas along with the profiles and integrated properties are publicly available through a dedicated Web page

Carbon-Enhanced Metal-Poor Stars. III. Main-Sequence Turn-Off Stars from the SDSS/SEGUE Sample

The chemical compositions of seven Carbon-Enhanced Metal-Poor (CEMP) turn-off stars are determined from high-resolution spectroscopy. Five of them are selected from the SDSS/SEGUE sample of metal-poor stars. The effective temperatures of these objects are all higher than 6000 K, while their metallicities, parametrized by [Fe/H], are all below -2. Six of our program objects exhibit high abundance ratios of barium ([Ba/H]> +1), suggesting large contributions of the products of former AGB companions via mass transfer across binary systems. Combining our results with previous studies provides a total of 20 CEMP main-sequence turn-off stars for which the abundances of carbon and at least some neutron-capture elements are determined. Inspection of the [C/H] ratios for this sample of CEMP turn-off stars show that they are generally higher than those of CEMP giants; their dispersion in this ratio is also smaller. We take these results to indicate that the carbon-enhanced material provided from the companion AGB star is preserved at the surface of turn-off stars with no significant dilution. In contrast, a large dispersion in the observed [Ba/H] is found for the sample of CEMP turn-off stars, suggesting that the efficiency of the s-process in very metal-poor AGB stars may differ greatly from star to star. Four of the six stars from the SDSS/SEGUE sample exhibit kinematics that are associated with membership in the outer-halo population, a remarkably high fraction.Comment: 45 pages, 10 figures, 10 tables, Astrophysical Journal, in pres

The Passing of Print

This paper argues that ephemera is a key instrument of cultural memory, marking the things intended to be forgotten. This important role means that when ephemera survives, whether accidentally or deliberately, it does so despite itself. These survivals, because they evoke all those other objects that have necessarily been forgotten, can be described as uncanny. The paper is divided into three main sections. The first situates ephemera within an uncanny economy of memory and forgetting. The second focuses on ephemera at a particular historical moment, the industrialization of print in the nineteenth century. This section considers the liminal place of newspapers and periodicals in this period, positioned as both provisional media for information as well as objects of record. The third section introduces a new configuration of technologies – scanners, computers, hard disks, monitors, the various connections between them – and considers the conditions under which born-digital ephemera can linger and return. Through this analysis, the paper concludes by considering digital technologies as an apparatus of memory, setting out what is required if we are not to be doubly haunted by the printed ephemera within the digital archive

Ongoing Formation of Bulges and Black Holes in the Local Universe: New Insights from GALEX

We analyze a volume-limited sample of massive bulge-dominated galaxies with data from both the Sloan Digital Sky Survey and the Galaxy Evolution Explorer (GALEX) satellite. The galaxies have central velocity dispersions greater than 100 km/s and stellar surface mass densities that lie above the value where galaxies transition from actively star forming to passive systems. The sample is limited to redshifts 0.03<z<0.07. At these distances, the SDSS spectra sample the light from the bulge-dominated central regions of the galaxies. The GALEX NUV data provide high sensitivity to low rates of global star formation in these systems. Our sample of bulge-dominated galaxies exhibits a much larger dispersion in NUV-r colour than in optical g-r colour. Nearly all of the galaxies with bluer NUV-r colours are AGN. Both GALEX images and SDSS colour profiles demonstrate that the excess UV light is associated with an extended disk. We find that galaxies with red outer regions almost never have a young bulge or a strong AGN. Galaxies with blue outer regions have bulges and black holes that span a wide range in age and accretion rate. Galaxies with young bulges and strongly accreting black holes almost always have blue outer disks. Our suggested scenario is one in which the source of gas that builds the bulge and black hole is a low mass reservoir of cold gas in the disk.The presence of this gas is a necessary, but not sufficient condition for bulge and black hole growth. Some mechanism must transport this gas inwards in a time variable way. As the gas in the disk is converted into stars, the galaxies will turn red, but further gas infall can bring them back into the blue NUV-r sequence.(Abridged)Comment: 34 pages, 16 figures. Accepted for the GALEX special issue of ApJ