2,854 research outputs found
Hot methane line lists for exoplanet and brown dwarf atmospheres
We present comprehensive experimental line lists of methane (CH4) at high
temperatures obtained by recording Fourier transform infrared emission spectra.
Calibrated line lists are presented for the temperatures 300 - 1400 degC at
twelve 100 degC intervals spanning the 960 - 5000 cm-1 (2.0 - 10.4 microns)
region of the infrared. This range encompasses the dyad, pentad and octad
regions, i.e., all fundamental vibrational modes along with a number of
combination, overtone and hot bands. Using our CH4 spectra, we have estimated
empirical lower state energies (Elow in cm-1) and our values have been
incorporated into the line lists along with line positions (cm-1) and
calibrated line intensities (S' in cm molecule-1). We expect our hot CH4 line
lists to find direct application in the modeling of planetary atmospheres and
brown dwarfs.Comment: Supplementary material is provided via the Astrophysical Journal
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Leading the way: finding genes for neurologic disease in dogs using genome-wide mRNA sequencing
Because of dogs' unique population structure, human-like disease biology, and advantageous genomic features, the canine system has risen dramatically in popularity as a tool for discovering disease alleles that have been difficult to find by studying human families or populations. To date, disease studies in dogs have primarily employed either linkage analysis, leveraging the typically large family size, or genome-wide association, which requires only modest-sized case and control groups in dogs. Both have been successful but, like most techniques, each requires a specific combination of time and money, and there are inherent problems associated with each. Here we review the first report of mRNA-Seq in the dog, a study that provides insights into the potential value of applying high-throughput sequencing to the study of genetic diseases in dogs. Forman and colleagues apply high-throughput sequencing to a single case of canine neonatal cerebellar cortical degeneration. This implementation of whole genome mRNA sequencing, the first reported in dog, is additionally unusual due to the analysis: the data was used not to examine transcript levels or annotate genes, but as a form of target capture that revealed the sequence of transcripts of genes associated with ataxia in humans. This approach entails risks. It would fail if, for example, the relevant transcripts were not sufficiently expressed for genotyping or were not associated with ataxia in humans. But here it pays off handsomely, identifying a single frameshift mutation that segregates with the disease. This work sets the stage for similar studies that take advantage of recent advances in genomics while exploiting the historical background of dog breeds to identify disease-causing mutations
Optimizing the ensemble for equilibration in broad-histogram Monte Carlo simulations
We present an adaptive algorithm which optimizes the statistical-mechanical
ensemble in a generalized broad-histogram Monte Carlo simulation to maximize
the system's rate of round trips in total energy. The scaling of the mean
round-trip time from the ground state to the maximum entropy state for this
local-update method is found to be O([N log N]^2) for both the ferromagnetic
and the fully frustrated 2D Ising model with N spins. Our new algorithm thereby
substantially outperforms flat-histogram methods such as the Wang-Landau
algorithm.Comment: 6 pages, 5 figure
Pelletizing
DURING the last 15 or 20 years we have witnessed an extra-ordinary increase in the quantity of artificial agglomera-tes used in blast-furnace burdens. This expansion has occurred in two fields, the first being sintering, a
technique applied particularly to the agglomeration of
low grade 'earthy' ores and to screenings from high quality
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Policing the COVID-19 pandemic: police officer well-being and commitment to democratic modes of policing
Police organisations have a wealth of experience in responding to emergencies, but COVID-19 is unprecedented in terms of the speed, scale and complexity of developing doctrine and its implementation by officers. The crisis also threw into sharp relief the fact that police policy and, crucially, practice are always implemented within wider social, political and economic contexts. Using online survey data collected from 325 police officers based at forces operating across different UK contexts (cities, conurbations, towns and rural areas), we seek to understand officer experiences and perceptions of policing COVID-19. In particular, we examine whether (internally) organisational climate and (externally) the UK government’s response to COVID-19 were important to (a) officers’ support for police use of force at times of emergency, (b) officer’s support for procedurally just policing at times of emergency, and (c) their health and well-being; and whether identification and perceptions of self-legitimacy mediate the associations between these variables. We show that a positive organisational climate was associated with less support for police use of force, more support for procedurally just policing and increased police officer health and well-being. Our results, however, suggest potential negative correlates of police officer self-legitimacy: higher levels of self-legitimacy were associated with poorer police officer health and well-being and increased support for police use of force. These results have important implications for our understanding of police officer well-being and police officers’ commitment to democratic modes of policing when faced with policing a pandemic
Random-cluster multi-histogram sampling for the q-state Potts model
Using the random-cluster representation of the -state Potts models we
consider the pooling of data from cluster-update Monte Carlo simulations for
different thermal couplings and number of states per spin . Proper
combination of histograms allows for the evaluation of thermal averages in a
broad range of and values, including non-integer values of . Due to
restrictions in the sampling process proper normalization of the combined
histogram data is non-trivial. We discuss the different possibilities and
analyze their respective ranges of applicability.Comment: 12 pages, 9 figures, RevTeX
Unravelling the spatial dependency of the complex solid-state chemistry of Pb in a paint micro-sample from Rembrandt's Homer using XRD-CT
Combination of improved multibondic method and the Wang-Landau method
We propose a method for Monte Carlo simulation of statistical physical models
with discretized energy. The method is based on several ideas including the
cluster algorithm, the multicanonical Monte Carlo method and its acceleration
proposed recently by Wang and Landau. As in the multibondic ensemble method
proposed by Janke and Kappler, the present algorithm performs a random walk in
the space of the bond population to yield the state density as a function of
the bond number. A test on the Ising model shows that the number of Monte Carlo
sweeps required of the present method for obtaining the density of state with a
given accuracy is proportional to the system size, whereas it is proportional
to the system size squared for other conventional methods. In addition, the new
method shows a better performance than the original Wang-Landau method in
measurement of physical quantities.Comment: 12 pages, 3 figure
Direct observation of the evolving metal–support interaction of individual cobalt nanoparticles at the titania and silica interface
Understanding the metal–support interaction (MSI) is crucial to comprehend how the catalyst support affects performance and whether this interaction can be exploited in order to design new catalysts with enhanced properties. Spatially resolved soft X-ray absorption spectroscopy (XAS) in combination with Atomic Force Microscopy (AFM) and Scanning Helium Ion-Milling Microscopy (SHIM) has been applied to visualise and characterise the behaviour of individual cobalt nanoparticles (CoNPs) supported on two-dimensional substrates (SiOxSi(100) (x < 2) and rutile TiO2(110)) after undergoing reduction–oxidation–reduction (ROR). The behaviour of the Co species is observed to be strongly dependent on the type of support. For SiOxSi a weaker MSI between Co and the support allows a complete reduction of CoNPs although they migrate and agglomerate. In contrast, a stronger MSI of CoNPs on TiO2 leads to only a partial reduction under H2 at 773 K (as observed from Co L3-edge XAS data) due to enhanced TiO2 binding of surface-exposed cobalt. SHIM data revealed that the interaction of the CoNPs is so strong on TiO2, that they are seen to spread at and below the surface and even to migrate up to ∼40 nm away. These results allow us to better understand deactivation phenomena and additionally demonstrate a new understanding concerning the nature of the MSI for Co/TiO2 and suggest that there is scope for careful control of the post-synthetic thermal treatment for the tuning of this interaction and ultimately the catalytic performance
Illuminating Choices for Library Prep: A Comparison of Library Preparation Methods for Whole Genome Sequencing of Cryptococcus neoformans Using Illumina HiSeq.
The industry of next-generation sequencing is constantly evolving, with novel library preparation methods and new sequencing machines being released by the major sequencing technology companies annually. The Illumina TruSeq v2 library preparation method was the most widely used kit and the market leader; however, it has now been discontinued, and in 2013 was replaced by the TruSeq Nano and TruSeq PCR-free methods, leaving a gap in knowledge regarding which is the most appropriate library preparation method to use. Here, we used isolates from the pathogenic fungi Cryptococcus neoformans var. grubii and sequenced them using the existing TruSeq DNA v2 kit (Illumina), along with two new kits: the TruSeq Nano DNA kit (Illumina) and the NEBNext Ultra DNA kit (New England Biolabs) to provide a comparison. Compared to the original TruSeq DNA v2 kit, both newer kits gave equivalent or better sequencing data, with increased coverage. When comparing the two newer kits, we found little difference in cost and workflow, with the NEBNext Ultra both slightly cheaper and faster than the TruSeq Nano. However, the quality of data generated using the TruSeq Nano DNA kit was superior due to higher coverage at regions of low GC content, and more SNPs identified. Researchers should therefore evaluate their resources and the type of application (and hence data quality) being considered when ultimately deciding on which library prep method to use
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