422 research outputs found
Microbes as engines of ecosystem function : When does community structure enhance predictions of ecosystem processes?
FUNDING This work was supported by NSF grant DEB-1221215 to DN, as well as grants supporting the generation of our datasets as acknowledged in their original publications and in Supplementary Table S1. ACKNOWLEDGMENT We thank the USGS Powell Center âNext Generation Microbesâ working group, anonymous reviews, Brett Melbourne, and Alan Townsend for valuable feedback on this project.Peer reviewedPublisher PD
Scalable, Shape-Specific, Top-Down Fabrication Methods for the Synthesis of Engineered Colloidal Particles
The search for a method to fabricate non-spherical colloidal particles from a variety of materials is of growing interest. As the commercialization of nanotechnology continues to expand, the ability to translate particle fabrication methods from a laboratory to an industrial scale is of increasing significance. In this article, we examine several of the most readily scalable top-down methods for the fabrication of such shape specific particles and compare their capabilities with respect to particle composition, size, shape and complexity as well as the scalability of the method. We offer an extensive examination of Particle Replication In Non-wetting Templates (PRINTÂź) with regards to the versatility and scalability of this technique. We also detail the specific methods used in PRINT particle fabrication, including harvesting, purification and surface modification techniques, with examination of both past and current methods
Control and systems software for the Cosmology Large Angular Scale Surveyor (CLASS)
The Cosmology Large Angular Scale Surveyor (CLASS) is an array of
polarization-sensitive millimeter wave telescopes that observes ~70% of the sky
at frequency bands centered near 40GHz, 90GHz, 150GHz, and 220GHz from the
Atacama desert of northern Chile. Here, we describe the architecture of the
software used to control the telescopes, acquire data from the various
instruments, schedule observations, monitor the status of the instruments and
observations, create archival data packages, and transfer data packages to
North America for analysis. The computer and network architecture of the CLASS
observing site is also briefly discussed. This software and architecture has
been in use since 2016, operating the telescopes day and night throughout the
year, and has proven successful in fulfilling its design goals.Comment: 19 pages, 8 figures, to appear in Proc. SPI
Prime movers : mechanochemistry of mitotic kinesins
Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation
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Association of Genetic Variants With Primary Open-Angle Glaucoma Among Individuals With African Ancestry.
Importance:Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders. Objectives:To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma. Design, Settings, and Participants:A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14âŻ917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma. Exposures:Genetic variants associated with primary open-angle glaucoma. Main Outcomes and Measures:Presence of primary open-angle glaucoma. Genome-wide significance was defined as Pâ<â5âĂâ10-8 in the discovery stage and in the meta-analysis of combined discovery and validation data. Results:A total of 2320 individuals with primary open-angle glaucoma (mean [interquartile range] age, 64.6 [56-74] years; 1055 [45.5%] women) and 2121 individuals without primary open-angle glaucoma (mean [interquartile range] age, 63.4 [55-71] years; 1025 [48.3%] women) were included in the discovery GWAS. The GWAS discovery meta-analysis demonstrated association of variants at amyloid-ÎČ A4 precursor protein-binding family B member 2 (APBB2; chromosome 4, rs59892895T>C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; Pâ=â2âĂâ10-8). The association was validated in an analysis of an additional 6937 affected individuals and 14âŻ917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; Pâ<â.001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; Pâ=â4âĂâ10-13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry. Conclusions and Relevance:In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies
Two Year Cosmology Large Angular Scale Surveyor (CLASS) Observations: Long Timescale Stability Achieved with a Front-End Variable-delay Polarization Modulator at 40 GHz
The Cosmology Large Angular Scale Surveyor (CLASS) is a four-telescope array
observing the largest angular scales () of the
cosmic microwave background (CMB) polarization. These scales encode information
about reionization and inflation during the early universe. The instrument
stability necessary to observe these angular scales from the ground is achieved
through the use of a variable-delay polarization modulator (VPM) as the first
optical element in each of the CLASS telescopes. Here we develop a demodulation
scheme used to extract the polarization timestreams from the CLASS data and
apply this method to selected data from the first two years of observations by
the 40 GHz CLASS telescope. These timestreams are used to measure the
noise and temperature-to-polarization () leakage present in the
CLASS data. We find a median knee frequency for the pair-differenced
demodulated linear polarization of 15.12 mHz and a leakage of
(95\% confidence) across the focal plane. We examine the
sources of noise present in the data and find the component of due
to atmospheric precipitable water vapor (PWV) has an amplitude of for 1 mm of PWV when evaluated at 10 mHz;
accounting for of the noise in the central pixels of the focal
plane. The low level of leakage and noise achieved
through the use of a front-end polarization modulator enables the observation
of the largest scales of the CMB polarization from the ground by the CLASS
telescopes.Comment: Submitted to Ap
Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC
The uncertainty on the calorimeter energy response to jets of particles is
derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the
calorimeter response to single isolated charged hadrons is measured and
compared to the Monte Carlo simulation using proton-proton collisions at
centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009
and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter
response to specific types of particles (positively and negatively charged
pions, protons, and anti-protons) is measured and compared to the Monte Carlo
predictions. Finally, the jet energy scale uncertainty is determined by
propagating the response uncertainty for single charged and neutral particles
to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3%
for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table,
submitted to European Physical Journal
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ENIGMA and global neuroscience: A decade of large-scale studies of the brain in health and disease across more than 40 countries.
This review summarizes the last decade of work by the ENIGMA (Enhancing NeuroImaging Genetics through Meta Analysis) Consortium, a global alliance of over 1400 scientists across 43 countries, studying the human brain in health and disease. Building on large-scale genetic studies that discovered the first robustly replicated genetic loci associated with brain metrics, ENIGMA has diversified into over 50 working groups (WGs), pooling worldwide data and expertise to answer fundamental questions in neuroscience, psychiatry, neurology, and genetics. Most ENIGMA WGs focus on specific psychiatric and neurological conditions, other WGs study normal variation due to sex and gender differences, or development and aging; still other WGs develop methodological pipelines and tools to facilitate harmonized analyses of "big data" (i.e., genetic and epigenetic data, multimodal MRI, and electroencephalography data). These international efforts have yielded the largest neuroimaging studies to date in schizophrenia, bipolar disorder, major depressive disorder, post-traumatic stress disorder, substance use disorders, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorders, epilepsy, and 22q11.2 deletion syndrome. More recent ENIGMA WGs have formed to study anxiety disorders, suicidal thoughts and behavior, sleep and insomnia, eating disorders, irritability, brain injury, antisocial personality and conduct disorder, and dissociative identity disorder. Here, we summarize the first decade of ENIGMA's activities and ongoing projects, and describe the successes and challenges encountered along the way. We highlight the advantages of collaborative large-scale coordinated data analyses for testing reproducibility and robustness of findings, offering the opportunity to identify brain systems involved in clinical syndromes across diverse samples and associated genetic, environmental, demographic, cognitive, and psychosocial factors
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