549 research outputs found
Laser-induced splittings in the nuclear magnetic resonance spectra of the rare gases
Circularly polarized laser field causes a shift in the nuclear magnetic
resonance (NMR) spectra of all substances. The shift is proportional to the
intensity of the laser beam and yields oppositely signed values for left- and
right-circularly polarized light, CPL -/+, respectively. Rapid switching -- in
the NMR time scale -- between CPL+ and CPL- gives rise to a splitting of the
NMR resonance lines. We present uncorrelated and correlated quadratic response
calculations of the splitting per unit of beam intensity in the NMR spectra of
Ne, Kr, and Xe. We study both the regions far away from
and near to optical resonance and predict off-resonance shifts of the order
0.01, 0.1, and Hz for Ne, Kr, and Xe,
respectively, for a beam intensity of 10 W/cm. Enhancement by several
orders of magnitude is predicted as the beam frequency approaches resonance.
Only then can the effect on guest Xe atoms be potentially useful as a
probe of the properties of the host material.Comment: 5 pages, 1 figur
Epidemiology of chronic hepatitis B and C in Victoria, Australia: insights and impacts from enhanced surveillance
Objective: To assess the impact of an enhanced viral hepatitis surveillance program on datacompleteness and on epidemiological assessment of affected populations.Methods: Notified cases of non-acute hepatitis B and C were analysed to determinedemographic characteristics and risk factors during the period prior to July 2015âJune 2016,and during enhanced surveillance of the period July 2016âJune 2017, during which timedoctors were contacted for information about new diagnoses.Results: During the enhanced period, completeness for country of birth and Indigenous statusdoubled for both hepatitis B and hepatitis C, from 18â37% to 48â65%. The incidence ratio ofhepatitis C among Aboriginal and Torres Strait Islander people increased from eight-fold to 11.4-fold, and the proportion of hepatitis B cases reported as born in China and Vietnam relative toother countries increased. New data fields identified that 12% of hepatitis C diagnoses occurredin a correctional facility, and 2% of hepatitis B cases were healthcare workers.Conclusions: Improved data completeness highlighted the underlying epidemiology ofchronic viral hepatitis, demonstrating the increased burden of infection among specific prioritypopulations.Implications for public health: Enhanced surveillance provides greater insight into theepidemiology of chronic viral hepatitis, identifying groups at risk and opportunities for publichealth action
Effect of Reduced versus Usual Lipid Emulsion Dosing on Bilirubin Neurotoxicity and Neurodevelopmental Impairment in Extremely Preterm Infants: Study Protocol for a Randomized Controlled Trial
BACKGROUND: Bilirubin neurotoxicity (BN) occurs in premature infants at lower total serum bilirubin levels than term infants and causes neurodevelopmental impairment. Usual dose lipid infusions in preterm infants may increase free fatty acids sufficiently to cause bilirubin displacement from albumin, increasing passage of unbound bilirubin (UB) into the brain leading to BN and neurodevelopmental impairment not reliably identifiable in infancy. These risks may be influenced by whether cycled or continuous phototherapy is used to control bilirubin levels.
OBJECTIVE: To assess differences in wave V latency measured by brainstem auditory evoked responses (BAER) at 34-36 weeks gestational age in infants bornââ€â750 g orâ\u3câ27 weeks\u27 gestational age randomized to receive usual or reduced dose lipid emulsion (half of the usual dose) irrespective of whether cycled or continuous phototherapy is administered.
METHODS: Pilot factorial randomized controlled trial (RCT) of lipid dosing (usual and reduced) with treatment groups balanced between cycled or continuous phototherapy assignment. Eligible infants are born atââ€â750 g orâ\u3câ27 weeks\u27 gestational age enrolled in the NICHD Neonatal Research Network RCT of cycled or continuous phototherapy. Infants will randomize 1:1 to reduced or usual dose lipid assignment during the first 2 weeks after birth and stratified by phototherapy assignment. Free fatty acids and UB will be measured daily using a novel probe. BAER testing will be performed at 34-36 weeks postmenstrual age or prior to discharge. Blinded neurodevelopmental assessments will be performed at 22-26 months. Intention-to-treat analyses will be performed with generalized linear mixed models with lipid dose and phototherapy assignments as random effects covariates, and assessment for interactions. Bayesian analyses will be performed as a secondary analysis.
DISCUSSION: Pragmatic trials are needed to evaluate whether lipid emulsion dosing modifies the effect of phototherapy on BN. This factorial design presents a unique opportunity to evaluate both therapies and their interaction. This study aims to address basic controversial questions about the relationships between lipid administration, free fatty acids, UB, and BN. Findings suggesting a reduced lipid dose can diminish the risk of BN would support the need for a large multicenter RCT of reduced versus usual lipid dosing
Can the gamma-ray source 3EG J2033+4118 be produced by the stellar system Cyg OB2 No.5?
We discuss the possibility that the stellar system Cyg OB2 No.5 can be a
gamma-ray source in the light of recent EGRET and radio data. This system is
formed by an O7 Ia + Ofpe/WN9 contact binary. A third star, probably a B0 V
star also associated with the system, is located at AU from the
primary. We estimate the expected gamma-ray luminosity from the colliding winds
region, the terminal shock of the wind, and the unstable zone at the base of
the wind, and conclude that, under very reasonable assumptions, Cyg OB2 No.5
can generate about a half of the gamma-ray flux detected from the positionally
coincident source 3EG J2033+4118. We suggest, then, that other O stars
belonging to the association, also placed within the 95 % probability EGRET
location contour, could contribute to the observed gamma-ray flux.Comment: Accepted for publication in Astronomy and Astrophysic
Supernovae and radio transients in M 82
We present optical and near-infrared (IR) photometry and near-IR spectroscopy
of SN 2004am, the only optically detected supernova (SN) in M 82. These
demonstrate that SN 2004am was a highly reddened type II-P SN similar to the
low luminosity type II-P events such as SNe 1997D and 2005cs. We show that SN
2004am was located coincident with the obscured super star cluster M 82-L, and
from the cluster age infer a progenitor mass of 12 +7/-3 Msun. In addition to
this, we present a high spatial resolution Gemini-N K-band adaptive optics
image of the site of SN 2008iz and a second transient of uncertain nature, both
detected so far only at radio wavelengths. Using image subtraction techniques
together with archival data from the Hubble Space Telescope, we are able to
recover a near-IR transient source co-incident with both objects. We find the
likely extinction towards SN 2008iz to be not more than Av ~ 10. The nature of
the second transient remains elusive and we regard an extremely bright
microquasar in M 82 as the most plausible scenario.Comment: 14 pages, 8 figures, accepted for publication in MNRA
Characterization and mapping of dwelling types for forest fire prevention
Définition des habitats isolés, diffus et groupés. Méthode de caractérisation et de cartographie de ces types d'habitat dans le contexte de prévention du risque d'incendie. Mise en relation des types d'habitat avec le risque d'incendie. / In a context of forest fire risk , the development of actions concerning wildfire prevention and land management is necessary and essential particularly in wildland urban interfaces (WUI). The term WUI' always includes components such as human presence and wildland vegetation. Both the hazard (probability of fire outbreak, distribution) and the vulnerability of urban areas can be characterized through the spatial organization of houses and vegetation. The first required step is to characterize and map WUI in large areas and at a large scale, which in turn requires qualifying different types of dwellings and mapping them. With this goal in view, the paper presents a brief synthesis of results coming from an exploratory process for the characterization of dwelling types (Lampin et al., 2007), and develops a method based on GIS-geo treatments to characterize different types of dwelling with regard to fire risk. Three types of dwellings were classified: isolated dwellings, scattered dwellings and clustered dwellings, using criteria based on the distance between houses, the size of clusters of houses and housing density, which can be mapped automatically. Within dwelling types, the density value of forest fire ignition changed and was twice as high for isolated dwellings as for clustered dwellings. The spatial organization of dwellings seems to have a real impact on fire occurrence. Thus maps of different dwelling types can be interpreted for use in developing fire fighting strategies or prevention actions concerning end-users such as forest and land planning managers or fire-fighters
Table S2: Differentially abundant OTUs within the gut of the mottled spinefoot (Siganus fuscescens).
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