Microrheological Characterisation of Anisotropic Materials

We describe the measurement of anisotropic viscoelastic moduli in complex soft materials, such as biopolymer gels, via video particle tracking microrheology of colloid tracer particles. The use of a correlation tensor to find the axes of maximum anisotropy, and hence the mechanical director, is described. The moduli of an aligned DNA gel are reported, as a test of the technique; this may have implications for high DNA concentrations in vivo. We also discuss the errors in microrheological measurement, and describe the use of frequency space filtering to improve displacement resolution, and hence probe these typically high modulus materials.Comment: 5 pages, 5 figures. Replaced after refereeing/ improvement. Main results are the same. The final, published version of the paper is here http://link.aps.org/abstract/PRE/v73/e03190

Evolution of the Gas Mass Fraction of Progenitors to Today's Massive Galaxies: ALMA Observations in the CANDELS GOODS-S Field

We present an ALMA survey of dust continuum emission in a sample of 70 galaxies in the redshift range z=2-5 selected from the CANDELS GOODS-S field. Multi-Epoch Abundance Matching (MEAM) is used to define potential progenitors of a z = 0 galaxy of stellar mass 1.5 10^11 M_sun. Gas masses are derived from the 850um luminosity. Ancillary data from the CANDELS GOODS-S survey are used to derive the gas mass fractions. The results at z<=3 are mostly in accord with expectations: The detection rates are 75% for the z=2 redshift bin, 50% for the z=3 bin and 0% for z>=4. The average gas mass fraction for the detected z=2 galaxies is f_gas = 0.55+/-0.12 and f_gas = 0.62+/-0.15 for the z=3 sample. This agrees with expectations for galaxies on the star-forming main sequence, and shows that gas fractions have decreased at a roughly constant rate from z=3 to z=0. Stacked images of the galaxies not detected with ALMA give upper limits to f_gas of <0.08 and <0.15, for the z=2 and z=3 redshift bins. None of our galaxies in the z=4 and z=5 sample are detected and the upper limit from stacked images, corrected for low metallicity, is f_gas<0.66. We do not think that lower gas-phase metallicities can entirely explain the lower dust luminosities. We briefly consider the possibility of accretion of very low-metallicity gas to explain the absence of detectable dust emission in our galaxies at z>4.Comment: Accepted for publication in the Astrophysical Journal. 33 pages; 11 figure

Towards a resolved Kennicutt-Schmidt law at high redshift

Massive galaxies in the distant Universe form stars at much higher rates than today. Although direct resolution of the star forming regions of these galaxies is still a challenge, recent molecular gas observations at the IRAM Plateau de Bure interferometer enable us to study the star formation efficiency on subgalactic scales around redshift z = 1.2. We present a method for obtaining the gas and star formation rate (SFR) surface densities of ensembles of clumps composing galaxies at this redshift, even though the corresponding scales are not resolved. This method is based on identifying these structures in position-velocity diagrams corresponding to slices within the galaxies. We use unique IRAM observations of the CO(3-2) rotational line and DEEP2 spectra of four massive star forming distant galaxies - EGS13003805, EGS13004291, EGS12007881, and EGS13019128 in the AEGIS terminology - to determine the gas and SFR surface densities of the identifiable ensembles of clumps that constitute them. The integrated CO line luminosity is assumed to be directly proportional to the total gas mass, and the SFR is deduced from the [OII] line. We identify the ensembles of clumps with the angular resolution available in both CO and [OII] spectroscopy; i.e., 1-1.5". SFR and gas surface densities are averaged in areas of this size, which is also the thickness of the DEEP2 slits and of the extracted IRAM slices, and we derive a spatially resolved Kennicutt-Schmidt (KS) relation on a scale of ~8 kpc. The data generally indicates an average depletion time of 1.9 Gyr, but with significant variations from point to point within the galaxies.Comment: 6 pages, 4 figures, 2 tables, accepted by Astronomy and Astrophysic

Optimization and activation of renewable durian husk for biosorption of lead (II) from a aqueous medium

Background: Biosorption of lead Pb(II) by durian husk activated carbon (DHAC) was investigated. The main aim of this work is to explore the effect of operating variables such as pH, biosorbent dose, temperature, initial metal ion concentration and contact time on the removal of Pb(II) from synthesized aqueous medium using a response surface methodology (RSM) technique. The experimentation was performed in two sets, namely set 1 and set 2. Results: For experimental set 1, pH was set to 7.0. The optimum conditions for the remaining parameters were determined to be 0.39 g DHAC dose, 60 min contact time and 100 mg L−1 of initial metal ion concentration, which yielded maximum biosorption capacity of 14.6 mg g−1. For experimental set 2, 41.27 °C, 8.95 and 99.96 mg L−1 were the optimum conditions determined for temperature, pH and initial Pb(II) concentration, respectively; which revealed a maximum adsorption capacity of 9.67 mg g−1. Characterization of the adsorbent revealed active functional groups such as hydroxyl, carboxylic, alcohol and hemicellulose. The equilibrium adsorption data obeyed the Langmuir isotherm and pseudo‐second‐order kinetic models with maximum Langmuir uptake of 36.1 mg g−1. Conclusions: The biosorbent was capable of reuse, so that the abundant durian husk could be utilized effectively for the removal of Pb(II) from polluted water

Scandinavian clinical practice guideline on fluid and drug therapy in adults with acute respiratory distress syndrome.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.The objective of the Scandinavian Society of Anaesthesiology and Intensive Care Medicine (SSAI) task force on fluid and drug therapy in adults with acute respiratory distress syndrome (ARDS) was to provide clinically relevant, evidence-based treatment recommendations according to standards for trustworthy guidelines.The guideline was developed according to standards for trustworthy guidelines, including a systematic review of the literature and use of the GRADE methodology for assessment of the quality of evidence and for moving from evidence to recommendations.A total of seven ARDS interventions were assessed. We suggest fluid restriction in patients with ARDS (weak recommendation, moderate quality evidence). Also, we suggest early use of neuromuscular blocking agents (NMBAs) in patients with severe ARDS (weak recommendation, moderate quality evidence). We recommend against the routine use of other drugs, including corticosteroids, beta2 agonists, statins, and inhaled nitric oxide (iNO) or prostanoids in adults with ARDS (strong recommendations: low- to high-quality evidence). These recommendations do not preclude the use of any drug or combination of drugs targeting underlying or co-existing disorders.This guideline emphasizes the paucity of evidence of benefit - and potential for harm - of common interventions in adults with ARDS and highlights the need for prudence when considering use of non-licensed interventions in this patient population.Scandinavian Society of Anaesthesiology and Intensive Care Medicine (SSAI

Dark Matter Fraction in Disk-Like Galaxies Over the Past 10 Gyr

We present an observational study of the dark matter fraction in star-forming disk-like galaxies up to redshift $z \sim 2.5$, selected from publicly available integral field spectroscropic surveys, namely KMOS3D}, KGES, and KROSS. We provide novel observational evidence, showing that at a fixed redshift, the dark matter fraction gradually increases with radius, indicating that the outskirts of galaxies are dark matter dominated, similarly to local star-forming disk galaxies. This observed dark matter fraction exhibits a decreasing trend with increasing redshift. However, on average, the fraction within the effective radius (upto outskirts) remains above 50\%, similar to locals. Furthermore, we investigated the relationships between the dark matter, baryon surface density, and circular velocity of galaxies. We observe a decreasing trend in the dark matter fraction as baryon surface densities increase, which is consistent across all stellar masses, redshift ranges, and radii, with a scatter of 0.13 dex. On the other hand, the correlation between the circular velocity at the outermost radius and the dark matter fraction within this radius has a relatively low scatter (0.11 dex), but its slope varies with stellar mass and with redshift, providing observational evidence of the dynamical evolution of the interplay between the baryonic and dark matter distributions with cosmic time. We observe that low stellar mass galaxies ($\log(M_{\star}/\mathrm{M_\odot}) \leq 10.0$) undergo a higher degree of evolution, which may be attributed to the hierarchical merging of galaxies.Comment: Comments are welcom