631 research outputs found
Star Formation in a Stellar Mass Selected Sample of Galaxies to z=3 from the GOODS NICMOS Survey (GNS)
We present a study of the star-forming properties of a stellar mass-selected
sample of galaxies in the GOODS NICMOS Survey (GNS), based on deep Hubble Space
Telescope imaging of the GOODS North and South fields. Using a stellar mass
selected sample, combined with HST/ACS and Spitzer data to measure both UV and
infrared derived star formation rates (SFR), we investigate the star forming
properties of a complete sample of ~1300 galaxies down to log M*=9.5 at
redshifts 1.5<z<3. Eight percent of the sample is made up of massive galaxies
with M*>10^11 Msun. We derive optical colours, dust extinctions, and
ultraviolet and infrared SFR to determine how the star formation rate changes
as a function of both stellar mass and time. Our results show that SFR
increases at higher stellar mass such that massive galaxies nearly double their
stellar mass from star formation alone over the redshift range studied, but the
average value of SFR for a given stellar mass remains constant over this 2 Gyr
period. Furthermore, we find no strong evolution in the SFR for our sample as a
function of mass over our redshift range of interest, in particular we do not
find a decline in the SFR among massive galaxies, as is seen at z < 1. The most
massive galaxies in our sample (log M*>11) have high average SFRs with values,
SFR(UV,corr) = 103+/-75 Msun/yr, yet exhibit red rest-frame (U-B) colours at
all redshifts. We conclude that the majority of these red high-redshift massive
galaxies are red due to dust extinction. We find that A(2800) increases with
stellar mass, and show that between 45% and 85% of massive galaxies harbour
dusty star formation. These results show that even just a few Gyr after the
first galaxies appear, there are strong relations between the global physical
properties of galaxies, driven by stellar mass or another underlying feature of
galaxies strongly related to the stellar mass.Comment: 18 pages, 10 figures, accepted for publication in MNRA
Interlaboratory comparison of particle filtration efficiency testing equipment
This work presents the results of two interlaboratory comparisons of particle
filtration efficiency measurements performed by a network of laboratories
across Canada and Australia. Testing across multiple layers of a common
verification material demonstrates a constant size-resolved quality factor when
layering uncharged materials. Size-resolved filtration curves also match
expectations, with increasingly size-dependent curves and a predictable
increase in the PFE. Candidate reference materials with controlled material
properties were also tested across multiple laboratories. Each set of materials
sharing a common charge level show specific trends with the material basis
weight. Respirators showed more consistency between the laboratories than the
other filters. However, across a majority of the tests, dark uncertainties,
which are otherwise unexplained variability between laboratories, are
significant. This leaves room to improve the test method by developing improved
verification procedures and additional reference materials.Comment: 14 pages, 8 figure
Partitioning and Mobility of Chromium in Iron-Rich Laterites from an Optimized Sequential Extraction Procedure
Chromium (Cr) leached from iron (Fe) (oxyhydr)oxide-rich tropical laterites can substantially impact downstream groundwater, ecosystems, and human health. However, its partitioning into mineral hosts, its binding, oxidation state, and potential release are poorly defined. This is in part due to the current lack of well-designed and validated Cr-specific sequential extraction procedures (SEPs) for laterites. To fill this gap, we have (i) first optimized a Cr SEP for Fe (oxyhydr)oxide-rich laterites using synthetic and natural Cr-bearing minerals and laterite references, (ii) used a complementary suite of techniques and critically evaluated existing non-laterite and non-Cr-optimized SEPs, compared to our optimized SEP, and (iii) confirmed the efficiency of our new SEP through analyses of laterites from the Philippines. Our results show that other SEPs inadequately leach Cr host phases and underestimate the Cr fractions. Our SEP recovered up to seven times higher Cr contents because it (a) more efficiently dissolves metal-substituted Fe phases, (b) quantitatively extracts adsorbed Cr, and (c) prevents overestimation of organic Cr in laterites. With this new SEP, we can estimate the mineral-specific Cr fractionation in Fe-rich tropical soils more quantitatively and thus improve our knowledge of the potential environmental impacts of Cr from lateritic areas
The relationship between lipoprotein A and other lipids with prostate cancer risk:A multivariable Mendelian randomisation study
BACKGROUND: Numerous epidemiological studies have investigated the role of blood lipids in prostate cancer (PCa) risk, though findings remain inconclusive to date. The ongoing research has mainly involved observational studies, which are often prone to confounding. This study aimed to identify the relationship between genetically predicted blood lipid concentrations and PCa. METHODS AND FINDINGS: Data for low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides (TG), apolipoprotein A (apoA) and B (apoB), lipoprotein A (Lp(a)), and PCa were acquired from genome-wide association studies in UK Biobank and the PRACTICAL consortium, respectively. We used a two-sample summary-level Mendelian randomisation (MR) approach with both univariable and multivariable (MVMR) models and utilised a variety of robust methods and sensitivity analyses to assess the possibility of MR assumptions violation. No association was observed between genetically predicted concentrations of HDL, TG, apoA and apoB, and PCa risk. Genetically predicted LDL concentration was positively associated with total PCa in the univariable analysis, but adjustment for HDL, TG, and Lp(a) led to a null association. Genetically predicted concentration of Lp(a) was associated with higher total PCa risk in the univariable (OR(weighted median) per standard deviation (SD) = 1.091; 95% CI 1.028 to 1.157; P = 0.004) and MVMR analyses after adjustment for the other lipid traits (OR(IVW) per SD = 1.068; 95% CI 1.005 to 1.134; P = 0.034). Genetically predicted Lp(a) was also associated with advanced (MVMR OR(IVW) per SD = 1.078; 95% CI 0.999 to 1.163; P = 0.055) and early age onset PCa (MVMR OR(IVW) per SD = 1.150; 95% CI 1.015,1.303; P = 0.028). Although multiple estimation methods were utilised to minimise the effect of pleiotropy, the presence of any unmeasured pleiotropy cannot be excluded and may limit our findings. CONCLUSIONS: We observed that genetically predicted Lp(a) concentrations were associated with an increased PCa risk. Future studies are required to understand the underlying biological pathways of this finding, as it may inform PCa prevention through Lp(a)-lowering strategies
Asthma phenotyping in primary care : applying the International Severe Asthma Registry eosinophil phenotype algorithm across all asthma severities.
Funding: The OPCRD is established and maintained by Optimum Patient Care (OPC) Ltd. This study was funded by AstraZeneca and conducted collaboratively with the OPRI Pte Ltd and OPC Global Ltd. Acknowledgements We thank James Zangrilli, MD, and the entire ISAR Steering Committee for their valued contribution to the design of the study and interpretation of findingsPeer reviewedPublisher PD
A randomized phase II clinical trial of dendritic cell vaccination following complete resection of colon cancer liver metastasis
Surgically resectable synchronic and metachronic liver metastases of colon cancer have high risk of relapse in spite
of standard-of-care neoadjuvant and adjuvant chemotherapy regimens. Dendritic cell vaccines loaded with autologous
tumor lysates were tested for their potential to avoid or delay disease relapses (NCT01348256). Patients with surgically
amenable liver metastasis of colon adenocarcinoma (n = 19) were included and underwent neoadjuvant chemotherapy,
surgery and adjuvant chemotherapy. Fifteen patients with disease-free resection margins were randomized 1:1 to receive
two courses of four daily doses of dendritic cell intradermal vaccinations versus observation. The trial had been originally
designed to include 56 patients but was curtailed due to budgetary restrictions. Follow-up of the patients indicates a
clear tendency to fewer and later relapses in the vaccine arm (median disease free survival –DFS-) 25.26 months, 95% CI 8.
74-n.r) versus observation arm (median DFS 9.53 months, 95% CI 5.32–18.88)
ESMO Clinical Research Observatory (ECRO): improving the efficiency of clinical research through rationalisation of bureaucracy
During the last years, there has been a dramatic increase in the administrative and bureaucratic burden associated with cli
Motor Decline in Clinically Presymptomatic Spinocerebellar Ataxia Type 2 Gene Carriers
BACKGROUND: Motor deficits are a critical component of the clinical characteristics of patients with spinocerebellar ataxia type 2. However, there is no current information on the preclinical manifestation of those motor deficits in presymptomatic gene carriers. To further understand and characterize the onset of the clinical manifestation in this disease, we tested presymptomatic spinocerebellar ataxia type 2 gene carriers, and volunteers, in a task that evaluates their motor performance and their motor learning capabilities. METHODS AND FINDINGS: 28 presymptomatic spinocerebellar ataxia type 2 gene carriers and an equal number of control volunteers matched for age and gender participated in the study. Both groups were tested in a prism adaptation task known to be sensible to both motor performance and visuomotor learning deficits. Our results clearly show that although motor learning capabilities are intact, motor performance deficits are present even years before the clinical manifestation of the disease start. CONCLUSIONS: The results show a clear deficit in motor performance that can be detected years before the clinical onset of the disease. This motor performance deficit appears before any motor learning or clinical manifestations of the disease. These observations identify the performance coefficient as an objective and quantitative physiological biomarker that could be useful to assess the efficiency of different therapeutic agents
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