2,268 research outputs found
An approach to complex texts in multiple documents
This entry gives a link to the full publication, free to read from this link. You may NOT repost the link on social media, etc.SSHRC, CFIPeer ReviewedThis article describes an approach to the treatment of texts in complex large textual traditions. Editors are interested in the text as it appears line-by-line in each document, and in how the versions of the text differ from document to document. It is useful to define a text as the record of an act of communication, inscribed in a document: thus, the instance of the act of communication we identify as Geoffrey Chaucer’s Canterbury Tales, as it appears in the Hengwrt manuscript. In this view, every text has a dual aspect: it is both the words as they are inscribed in a particular document, and as they constitute an act of communication and its parts. This presents challenges for scholars who wish to record both aspects. In encoding implementations, these two aspects are commonly treated as ‘overlapping hierarchies’. However, the ‘overlapping hierarchy’ model does not deal with cases where text segments are not contiguous in either aspect and cannot overlap cleanly. To meet these cases, the Textual Communities project developed an architecture in which the two aspects are represented as distinct and independent hierarchies (trees), with text segments referenced to nodes on each tree. The linking of text segments to the two trees is managed by a JSON database, accessed through transcription and collation tools presented in a Web interface. Textual Communities does not implement the whole of this architecture in terms of validation, ingestion, and processing. Full exploration and implementation of the architecture here described are challenges for future scholars
HST Imaging Polarimetry of the Gravitational Lens FSC10214+4724
We present imaging polarimetry of the extremely luminous, redshift 2.3 IRAS
source FSC10214+4724. The observations were obtained with HST's Faint Object
Camera in the F437M filter, which is free of strong emission lines. The 0.7
arcsec long arc is unresolved to 0.04 arcsec FWHM in the transverse direction,
and has an integrated polarization of 28 +/- 3 percent, in good agreement with
ground-based observations. The polarization position angle varies along the arc
by up to 35 deg. The overall position angle is 62 +/- 3 deg east of north. No
counterimage is detected to B = 27.5 mag (), giving an observed arc to
counterimage flux ratio greater than 250, considerably greater than the flux
ratio of 100 measured previously in the I-band. This implies that the
configuration of the object in the source plane at the B-band is different from
that at I-band, and/or that the lensing galaxy is dusty.Comment: 17 pages, 3 figures. Accepted for publication in Astronomical
Journal, February 199
Isomerization dynamics of a buckled nanobeam
We analyze the dynamics of a model of a nanobeam under compression. The model
is a two mode truncation of the Euler-Bernoulli beam equation subject to
compressive stress. We consider parameter regimes where the first mode is
unstable and the second mode can be either stable or unstable, and the
remaining modes (neglected) are always stable. Material parameters used
correspond to silicon. The two mode model Hamiltonian is the sum of a
(diagonal) kinetic energy term and a potential energy term. The form of the
potential energy function suggests an analogy with isomerisation reactions in
chemistry. We therefore study the dynamics of the buckled beam using the
conceptual framework established for the theory of isomerisation reactions.
When the second mode is stable the potential energy surface has an index one
saddle and when the second mode is unstable the potential energy surface has an
index two saddle and two index one saddles. Symmetry of the system allows us to
construct a phase space dividing surface between the two "isomers" (buckled
states). The energy range is sufficiently wide that we can treat the effects of
the index one and index two saddles in a unified fashion. We have computed
reactive fluxes, mean gap times and reactant phase space volumes for three
stress values at several different energies. In all cases the phase space
volume swept out by isomerizing trajectories is considerably less than the
reactant density of states, proving that the dynamics is highly nonergodic. The
associated gap time distributions consist of one or more `pulses' of
trajectories. Computation of the reactive flux correlation function shows no
sign of a plateau region; rather, the flux exhibits oscillatory decay,
indicating that, for the 2-mode model in the physical regime considered, a rate
constant for isomerization does not exist.Comment: 42 pages, 6 figure
Atrial fibrillation in hemodialysis patients: clinical features and associations with anticoagulant therapy
Using data from the international Dialysis Outcomes and Practice Patterns Study (DOPPS), we determined incidence, prevalence, and outcomes among hemodialysis patients with atrial fibrillation. Cox proportional hazards models, to identify associations with newly diagnosed atrial fibrillation and clinical outcomes, were stratified by country and study phase and adjusted for descriptive characteristics and comorbidities. Of 17,513 randomly sampled patients, 2188 had preexisting atrial fibrillation, with wide variation in prevalence across countries. Advanced age, non-black race, higher facility mean dialysate calcium, prosthetic heart valves, and valvular heart disease were associated with higher risk of new atrial fibrillation. Atrial fibrillation at study enrollment was positively associated with all-cause mortality and stroke. The CHADS2 score identified approximately equal-size groups of hemodialysis patients with atrial fibrillation with low (less than 2) and higher risk (more than 4) for subsequent strokes on a per 100 patient-year basis. Among patients with atrial fibrillation, warfarin use was associated with a significantly higher stroke risk, particularly in those over 75 years of age. Our study shows that atrial fibrillation is common and associated with elevated risk of adverse clinical outcomes, and this risk is even higher among elderly patients prescribed warfarin. The effectiveness and safety of warfarin in hemodialysis patients require additional investigation
A Novel Strategy for Determining Protective Antigens of the Parapoxvirus, Orf Virus
AbstractWe investigated the feasibility of using vaccinia virus (VAC) recombinants containing large multigene fragments of orf virus DNA to identify protective antigens of orf virus (OV). Sixteen OV strain NZ2 DNA fragments with an average size of 11.4 kb were recombined into VAC strain Lister. Each fragment was mapped relative to OV restriction endonuclease maps but was otherwise uncharacterized. Together the recombinants represent 95% of the OV genome in an overlapping manner. Immunofluorescence showed all 16 constructs expressed products recognized by OV antiserum and radioimmune precipitation with the same antiserum allowed the localization of the major antigens of OV to specific recombinants. These data indicated the approximate genomic locations of the genes encoding the OV major antigens and showed that their expression was authentic rather than resulting from read through from VAC sequences adjacent to the site of recombination. Vaccination of OV-naive sheep with the recombinant library provided protection against a subsequent challenge with virulent OV. These data confirm the feasibility of the proposed strategy
Silicon and Nickel Enrichment in Planet-Host Stars: Observations and Implications for the Core-Accretion Theory of Planet Formation
We present evidence that stars with planets exhibit statistically significant
silicon and nickel enrichment over the general metal-rich population. We also
present simulations which predict silicon enhancement of planet hosts within
the context of the core-accretion hypothesis for giant planet formation.
Because silicon and oxygen are both alpha elements, [Si/Fe] traces [O/Fe], so
the silicon enhancement in planet hosts predicts that these stars are
oxygen-rich as well. We present new numerical simulations of planet formation
by core accretion that establish the timescale on which a Jovian planet reaches
rapid gas accretion, t_rga, as a function of solid surface density sigma_solid:
(t_rga / 1 Myr) = (sigma_solid / 25.0 g cm^{-2})^{-1.44}. This relation enables
us to construct Monte Carlo simulations that predict the fraction of star-disk
systems that form planets as a function of [Fe/H], [Si/Fe], disk mass, outer
disk radius and disk lifetime. Our simulations reproduce both the known
planet-metallicity correlation and the planet-silicon correlation reported in
this paper. The simulations predict that 16% of Solar-type stars form
Jupiter-mass planets, in agreement with 12% predicted from extrapolation of the
observed planet frequency-semimajor axis distribution. Although a simple
interpretation of core accretion predicts that the planet-silicon correlation
should be much stronger than the planet-nickel correlation, we observe the same
degree of silicon and nickel enhancement in planet hosts. If this result
persists once more planets have been discovered, it might indicate a complexity
in the chemistry of planet formation beyond the simple accumulation of solids
in the core accretion theory.Comment: 45 pages, including 12 figures, accepted for publication in the
Astrophysical Journa
Broad anti-hepatitis C virus (HCV) antibody responses are associated with improved clinical disease parameters in chronic HCV infection
During hepatitis C virus (HCV) infection broadly neutralizing antibody (bNAb) responses targeting E1E2 envelope glycoproteins are generated in many individuals. It is unclear if these antibodies play a protective or a pathogenic role during chronic infection. In this study, we investigated whether bNAb responses in individuals with chronic infection were associated with differences in clinical presentation. Patient-derived purified serum IgG was used to assess the breadth of HCV E1E2 binding and neutralization activity of HCV pseudoparticles. Two panels were compared, bearing viral envelope proteins representing either an inter-genotype or an intra-genotype (gt) 1 group. We found that HCV viral load was negatively associated with strong cross-genotypic E1E2 binding (P=0.03). Overall we observed only modest correlation between total E1E2 binding and neutralizing ability. The breadth of inter-genotype neutralization did not correlate with any clinical parameters, however, analysis of individuals with gt 1 HCV infection (n=20), using an intra-genotype pseudoparticle panel, found a strong association between neutralization breadth and reduced liver fibrosis (P=0.006). Broad bNAb response in our chronic cohort was associated with a single nucleotide polymorphism (SNP) in the HLA-DQB1 gene (P=0.038) as previously reported in an acute cohort. Furthermore bNAbs in these individuals targeted more than one region of E2 neutralizing epitopes as assessed through cross-competition of patient bNAbs with well-characterized E2 antibodies. We conclude that bNAb responses in chronic gt1 infection are associated with lower rates of fibrosis and host genetics may play a role in the ability to raise such responses.
IMPORTANCE: Globally there are 130-150 million people with chronic HCV infection. Typically the disease is progressive and is a major cause of severe liver cirrhosis and hepatocellular carcinoma. While it is known that neutralizing antibodies have a role in spontaneous clearance during acute infection, little is known about their role in chronic infection. In the present work we investigate the antibody response in a cohort of chronically infected individuals and find that a broad neutralizing antibody response is protective, with reduced levels of liver fibrosis and cirrhosis. We also find an association with SNPs in class II HLA genes and the presence of a broad neutralizing response indicating that antigen presentation may be important for production of HCV neutralizing antibodies
Individual hurricane evacuation intentions during the COVID-19 pandemic: insights for risk communication and emergency management policies
The U.S. 2020 hurricane season was extraordinary because of a record number of named storms coinciding with the COVID-19 pandemic. This study draws lessons on how individual hurricane preparedness is influenced by the additional risk stemming from a pandemic, which turns out to be a combination of perceptions of flood and pandemic risks that have opposite effects on preparedness behavior. We conducted a survey in early June 2020 of 600 respondents in flood-prone areas in Florida to obtain insights into households’ risk perceptions and preparedness for the upcoming hurricane season under COVID-19. The results show that concerns over COVID-19 dominated flood risk perceptions and negatively impacted people’s evacuation intentions. Whereas hotel costs were the main obstacle to evacuating during Hurricane Dorian in 2019 in the same geographic study area, the main evacuation obstacle identified in the 2020 hurricane season is COVID-19. Our statistical analyses investigating the factors influencing evacuation intentions show that older individuals are less likely to evacuate under a voluntary order, because they are more concerned about the consequences of becoming infected by COVID-19. We observe similar findings based on a real-time survey we conducted in Florida with another group of respondents under the threat of Hurricane Eta at the end of the hurricane season in November 2020. We discuss the implications of our findings for risk communication and emergency management policies that aim to improve hurricane preparedness when dealing with additional health risks such as a pandemic, a situation that may be exacerbated under the future climate
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