A New Measurement of the Stellar Mass Density at z~5: Implications for the Sources of Cosmic Reionization

We present a new measurement of the integrated stellar mass per comoving volume at redshift 5 determined via spectral energy fitting drawn from a sample of 214 photometrically-selected galaxies with z'<26.5 in the southern GOODS field. Following procedures introduced by Eyles et al. (2005), we estimate stellar masses for various sub-samples for which reliable and unconfused Spitzer IRAC detections are available. A spectroscopic sample of 14 of the most luminous sources with =4.92 provides a firm lower limit to the stellar mass density of 1e6 Msun/Mpc^3. Several galaxies in this sub-sample have masses of order 10^11 Msun implying significant earlier activity occurred in massive systems. We then consider a larger sample whose photometric redshifts in the publicly-available GOODS-MUSIC catalog lie in the range 4.4 <z 5.6. Before adopting the GOODS-MUSIC photometric redshifts, we check the accuracy of their photometry and explore the possibility of contamination by low-z galaxies and low-mass stars. After excising probable stellar contaminants and using the z'-J color to exclude any remaining foreground red galaxies, we conclude that 196 sources are likely to be at z~5. The implied mass density from the unconfused IRAC fraction of this sample, scaled to the total available, is 6e6 Msun/Mpc^3. We discuss the uncertainties as well as the likelihood that we have underestimated the true mass density. Including fainter and quiescent sources the total integrated density could be as high as 1e7 Msun/Mpc^3. Using the currently available (but highly uncertain) rate of decline in the star formationhistory over 5 <z< 10, a better fit is obtained for the assembled mass at z~5 if we admit significant dust extinction at early times or extend the luminosity function to very faint limits. [abridged]Comment: Accepted for Publication in ApJ, 39 page

Using deuterated PAH amendments to validate chemical extraction methods to predict PAH bioavailability in soils

Validating chemical methods to predict bioavailable fractions of polycyclic aromatic hydrocarbons (PAHs) by comparison with accumulation bioassays is problematic. Concentrations accumulated in soil organisms not only depend on the bioavailable fraction but also on contaminant properties. A historically contaminated soil was freshly spiked with deuterated PAHs (dPAHs). dPAHs have a similar fate to their respective undeuterated analogues, so chemical methods that give good indications of bioavailability should extract the fresh more readily available dPAHs and historic more recalcitrant PAHs in similar proportions to those in which they are accumulated in the tissues of test organisms. Cyclodextrin and butanol extractions predicted the bioavailable fraction for earthworms (Eisenia fetida) and plants (Lolium multiflorum) better than the exhaustive extraction. The PAHs accumulated by earthworms had a larger dPAH:PAH ratio than that predicted by chemical methods. The isotope ratio method described here provides an effective way of evaluating other chemical methods to predict bioavailability

A synoptic view of solar transient evolution in the inner heliosphere using the Heliospheric Imagers on STEREO

By exploiting data from the STEREO/heliospheric imagers (HI) we extend a well-established technique developed for coronal analysis by producing time-elongation plots that reveal the nature of solar transient activity over a far more extensive region of the heliosphere than previously possible from coronagraph images. Despite the simplicity of these plots, their power in demonstrating how the plethora of ascending coronal features observed near the Sun evolve as they move antisunward is obvious. The time-elongation profile of a transient tracked by HI can, moreover, be used to establish its angle out of the plane-of-the-sky; an illustration of such analysis reveals coronal mass ejection material that can be clearly observed propagating out to distances beyond 1AU. This work confirms the value of the time-elongation format in identifying/characterising transient activity in the inner heliosphere, whilst also validating the ability of HI to continuously monitor solar ejecta out to and beyond 1A

A case study using the model H+H2 and F+H2 reactions with aligned and anti- aligned H2

We propose a method to steer the outcome of reactive atom-diatom scattering, using rotational wavepackets excited by strong non-resonant laser pulses. Full close-coupled quantum mechanical scattering calculations of the D+H2 and F+H2 reactions are presented, where the H2 molecule exists as a coherent superposition of rotational states. The nuclear spin selective control over the molecular bond axis alignment afforded by the creation of rotational wavepackets is applied to reactive scattering systems, enabling a nuclear spin selective influence to be exerted over the reactive dynamics. The extension of the conventional eigenstate-to-eigenstate scattering problem to the case in which the initial state is composed of a coherent superposition of rotational states is detailed, and a selection of example calculations are discussed, along with their mechanistic implications. The feasibility of the corresponding experiments is considered, and a suitable simple two pulse laser scheme is shown to strongly differentiate the reactivities of o-H2 and p-H2

Glaciolacustrine Sedimentation During Advance and Retreat of the Cordilleran Ice Sheet in Central British Colombia

Thick (400+ m) and well exposed sediment fills in the Fraser and Chilcotin river valleys of central British Columbia record contrasting glaciolacustrine environments of at least two glaciations. The oldest glaciolacustrine sequence comprises deformed gravel, sand, mud, and diamict fades deposited, in part, on stagnant ice trapped in deep narrow valleys at the end of the penultimate glaciation (Early Wisconsinan or older). Younger glaciolacustrine sequences date from the advance and retreat phases of the Late Wisconsinan Fraser Glaciation {ca. 25-10 ka) and infill a Middle Wisconsinan drainage system cut across older sediments. The Late Wisconsinan advance sequence is dominated by diamict (debris-flow) fades that pass upward into silts. The diamict fades consist largely of reworked older Pleistocene drift and poorly lithified Cretaceous and Tertiary sediments. They record the focusing of large volumes of sediment into one or more glacial lakes occupying deep narrow troughs. Weakly bedded silts in the upper part of the sequence may have been deposited when the lake(s) deepened as glaciers continued to advance and thicken over the study area. It is possible that some advance glaciolacustrine sediments accumulated in subglacial water bodies. Late Wisconsinan deglacial lake sediments form a relatively thin, discontinuous capping in the area and conform to classical notions of gladolacustrine sedimentation involving a seasonal or 'varved' regime. In contrast, no seasonal pattern of sedimentation can be identified in older sequences where the overriding influence on deposition has been the presence of steep subaqueous slopes, buried ice masses, and high sediment fluxes; these, in combination, caused near-continuous downslope movement and resedimentation.Les épaisses accumulations de sédiments (400+ m) qui comblent les vallées du Fraser et de la Chilcotin River permettent de distinguer les milieux glaciola-custres issus d'au moins deux glaciations. La séquence glaciolacustre la plus ancienne comprend des faciès déformés de gravier, sable, boue et diamicton mis en place, en partie, sur une glace stagnante emprisonnée dans de profondes vallées étroites à la fin de l'avant-dernière glaciation (Wisconsinien inférieur ou avant). Les séquences glaciolacustres plus récentes datent des phases d'avancée et de retrait de la Glaciation de Fraser au Wisconsinien supérieur (vers 25-10 ka) et ont comblé un réseau de drainage du Wisconsinien moyen entaillé dans des sédiments plus anciens. La séquence d'avancée glaciaire du Wisconsinien supérieur est dominée par un faciès de diamicton (coulée de débris) remplacé vers le haut par des silts. Le faciès de diamicton est en grande partie constitué de dépôts glaciaires anciens du Pleistocene remaniés et de sédiments peu consolidés du Crétacé et du Tertiaire. Ils témoignent de l'accumulation de grandes quantités de sédiments dans un ou plusieurs lacs glaciaires resserrés dans des dépressions profondes et étroites. Dans la partie supérieure de la séquence, les silts faiblement stratifiés ont probablement été mis en place lorsque les lacs se sont approfondis avec l'avancée des glaciers. Il est possible que des sédiments glaciolacustres se soient accumulés dans des nappes sous-glaciaires au cours de l'avancée glaciaire. Les sédiments lacustres de retrait glaciaire du Wisconsinien supérieur forment une mince couverture discontinue et se sont déposés selon un régime saisonnier ou varvaire.Dicke (+ 400m) und gut ausgesetzte Sediment-fùllungen in den Fraser- und Chilcotin-Flusstalern im Zentrum von British Columbia bezeugen kontrastierende glaziallimnische Umwelten von mindestens zwei Vereisungen. Die àlteste glaziallimnische Sequenz besteht aus deformierten Fazies aus Kies, Sand, Schlamm und Diamikton, die zum Teil auf stagnierendem Eis abgelagert wurden, das in tiefen, engen Tàlern am Ende der vorletzten Vereisung (frûhes Wisconsin oder alter) fest-steckte. Jûngere glaziallimnische Sequenzen stammen von den Vorstoss- und Rùckzugsphasen der Fraser-Vereisung im spaten Wisconsin (etwa 25-10 ka) und haben ein Drânage-System des mittleren Wisconsin, das sich quer durch altère Sedimente eingekerbt hat, ausgefùiit. Die Vorstoss-Sequenz aus dem spaten Wisconsin wird von Diamikton (Trûmmer-Strômung)-Fazies beherrscht, die nach oben hin in Schlamm ùbergehen. Die Diamikton-Fazies bestehen weitgehend aus umgearbeiteten âlteren glazialen Ablagerungen aus dem Pleistozân und gering verfestigten Sedimenten aus der Kreidezeit und dem Tertiàr. Sie bezeugen die Konzentration grosser Sedimentvolumen in einem oder mehreren glazialen Seen, die sich in tiefen engen Trôgen befanden. Schwach geschichteter Schlamm im oberen Teil der Sequenz ist môglicherweise abgelagert worden, als der See/die Seen tiefer wurden, wàhrend die Gletscher ùber dem untersuchten Gebiet weiter vorstiessen und sich verdickten. Es ist môglich, dass einige glaziallimnische Vorstoss-Sedimente sich in subglazialen Wasserflâchen akkumulierten. Glaziale Seen-Rùckzugssedimente aus dem spaten Wisconsin bilden in dem Gebiet eine relativ dûnne, nichtkontinuierliche Decke und ent-sprechen der klassischen Vorstellung glazial-limnischer Sedimentierung mit periodischem oder "Warwen"-System

Atom-diatom scattering dynamics of spinning molecules

We present full quantum mechanical scattering calculations using spinning molecules as target states for nuclear spin selective atom-diatom scattering of reactive D+H2 and F+H2 collisions. Molecules can be forced to rotate uni- directionally by chiral trains of short, non-resonant laser pulses, with different nuclear spin isomers rotating in opposite directions. The calculations we present are based on rotational wavepackets that can be created in this manner. As our simulations show, target molecules with opposite sense of rotation are predominantly scattered in opposite directions, opening routes for spatially and quantum state selective scattering of close chemical species. Moreover, two-dimensional state resolved differential cross sections reveal detailed information about the scattering mechanisms, which can be explained to a large degree by a classical vector model for scattering with spinning molecules

'Targeting care: tailoring non-surgical management according to clinical presentation'

International evidence-based guidelines recommend a multitude of nonsurgical treatment options for the management of osteoarthritis. This article summarizes the evidence available for patient characteristics that have been analyzed as potential predictors of response to nonsurgical interventions for patients with hip and knee osteoarthritis. The specific variables targeted for this review include body mass index, psychological factors, muscle strength, tibiofemoral alignment, radiographic changes, and signs of inflammation. Several studies provide moderate to good evidence of potential predictors of response to nonsurgical treatments, and areas for future research are illuminated. Copyright 2013 Elsevier Inc. All rights reserved

'Targeting care: tailoring non-surgical management according to clinical presentation'

International evidence-based guidelines recommend a multitude of nonsurgical treatment options for the management of osteoarthritis. This article summarizes the evidence available for patient characteristics that have been analyzed as potential predictors of response to nonsurgical interventions for patients with hip and knee osteoarthritis. The specific variables targeted for this review include body mass index, psychological factors, muscle strength, tibiofemoral alignment, radiographic changes, and signs of inflammation. Several studies provide moderate to good evidence of potential predictors of response to nonsurgical treatments, and areas for future research are illuminated. Copyright 2013 Elsevier Inc. All rights reserved