507 research outputs found
Frequency and risk factors for prevalent, incident, and persistent genital carcinogenic human papillomavirus infection in sexually active women: community based cohort study
Objective To investigate frequency and risk factors for prevalent, incident, and persistent carcinogenic human papillomavirus (HPV) in young women before the introduction of immunisation against HPV types 16 and 18 for schoolgirls
Early Radio and X-Ray Observations of the Youngest Nearby Type Ia Supernova PTF 11kly (SN 2011fe)
On 2011 August 24 (UT) the Palomar Transient Factory (PTF) discovered PTF11kly (SN 2011fe), the youngest
and most nearby Type Ia supernova (SN Ia) in decades. We followed this event up in the radio (centimeter and
millimeter bands) and X-ray bands, starting about a day after the estimated explosion time.We present our analysis
of the radio and X-ray observations, yielding the tightest constraints yet placed on the pre-explosion mass-loss rate
from the progenitor system of this supernova. We find a robust limit of áč ⟠10^(â8)(w/100 km s^(â1))M_â yr^(â1) from
sensitive X-ray non-detections, as well as a similar limit from radio data, which depends, however, on assumptions
about microphysical parameters. We discuss our results in the context of single-degenerate models for SNe Ia and
find that our observations modestly disfavor symbiotic progenitor models involving a red giant donor, but cannot
constrain systems accreting from main-sequence or sub-giant stars, including the popular supersoft channel. In
view of the proximity of PTF11kly and the sensitivity of our prompt observations, we would have to wait for a long
time (a decade or longer) in order to more meaningfully probe the circumstellar matter of SNe Ia
Constraints on the Progenitor System of the Type Ia Supernova SN 2011fe/PTF11kly
Type Ia supernovae (SNe) serve as a fundamental pillar of modern cosmology,
owing to their large luminosity and a well-defined relationship between
light-curve shape and peak brightness. The precision distance measurements
enabled by SNe Ia first revealed the accelerating expansion of the universe,
now widely believed (though hardly understood) to require the presence of a
mysterious "dark" energy. General consensus holds that Type Ia SNe result from
thermonuclear explosions of a white dwarf (WD) in a binary system; however,
little is known of the precise nature of the companion star and the physical
properties of the progenitor system. Here we make use of extensive historical
imaging obtained at the location of SN 2011fe/PTF11kly, the closest SN Ia
discovered in the digital imaging era, to constrain the visible-light
luminosity of the progenitor to be 10-100 times fainter than previous limits on
other SN Ia progenitors. This directly rules out luminous red giants and the
vast majority of helium stars as the mass-donating companion to the exploding
white dwarf. Any evolved red companion must have been born with mass less than
3.5 times the mass of the Sun. These observations favour a scenario where the
exploding WD of SN 2011fe/PTF11kly, accreted matter either from another WD, or
by Roche-lobe overflow from a subgiant or main-sequence companion star.Comment: 22 pages, 6 figures, submitte
PTF11eon/SN2011dh: Discovery of a Type IIb Supernova From a Compact Progenitor in the Nearby Galaxy M51
On May 31, 2011 UT a supernova (SN) exploded in the nearby galaxy M51 (the
Whirlpool Galaxy). We discovered this event using small telescopes equipped
with CCD cameras, as well as by the Palomar Transient Factory (PTF) survey, and
rapidly confirmed it to be a Type II supernova. Our early light curve and
spectroscopy indicates that PTF11eon resulted from the explosion of a
relatively compact progenitor star as evidenced by the rapid shock-breakout
cooling seen in the light curve, the relatively low temperature in early-time
spectra and the prompt appearance of low-ionization spectral features. The
spectra of PTF11eon are dominated by H lines out to day 10 after explosion, but
initial signs of He appear to be present. Assuming that He lines continue to
develop in the near future, this SN is likely a member of the cIIb (compact
IIb; Chevalier and Soderberg 2010) class, with progenitor radius larger than
that of SN 2008ax and smaller than the eIIb (extended IIb) SN 1993J progenitor.
Our data imply that the object identified in pre-explosion Hubble Space
Telescope images at the SN location is possibly a companion to the progenitor
or a blended source, and not the progenitor star itself, as its radius (~10^13
cm) would be highly inconsistent with constraints from our post-explosion
photometric and spectroscopic data
Metabolic profiling of aortic stenosis and hypertrophic cardiomyopathy identifies mechanistic contrasts in substrate utilization
Open Access via the Wiley Agreement UKRI | Medical Research Council (MRC), Grant/Award Number: MR/ P011705/1, MC_UP_A090_1006 and MR/S010483; British Heart Foundation (BHF); NIHR | NIHR Oxford Biomedical Research Centre (OxBRC)Peer reviewe
Metabolic profiling of aortic stenosis and hypertrophic cardiomyopathy identifies mechanistic contrasts in substrate utilization
Aortic stenosis (AS) and hypertrophic cardiomyopathy (HCM) are distinct disorders leading to left ventricular hypertrophy (LVH), but whether cardiac metabolism substantially differs between these in humans remains to be elucidated. We undertook an invasive (aortic root, coronary sinus) metabolic profiling in patients with severe AS and HCM in comparison with nonâLVH controls to investigate cardiac fuel selection and metabolic remodeling. These patients were assessed under different physiological states (at rest, during stress induced by pacing). The identified changes in the metabolome were further validated by metabolomic and orthogonal transcriptomic analysis, in separately recruited patient cohorts. We identified a highly discriminant metabolomic signature in severe AS in all samples, regardless of sampling site, characterized by striking accumulation of longâchain acylcarnitines, intermediates of fatty acid transport across the inner mitochondrial membrane, and validated this in a separate cohort. Mechanistically, we identify a downregulation in the PPARâα transcriptional network, including expression of genes regulating fatty acid oxidation (FAO). In silico modeling of ÎČâoxidation demonstrated that flux could be inhibited by both the accumulation of fatty acids as a substrate for mitochondria and the accumulation of mediumâchain carnitines which induce competitive inhibition of the acylâCoA dehydrogenases. We present a comprehensive analysis of changes in the metabolic pathways (transcriptome to metabolome) in severe AS, and its comparison to HCM. Our results demonstrate a progressive impairment of ÎČâoxidation from HCM to AS, particularly for FAO of longâchain fatty acids, and that the PPARâα signaling network may be a specific metabolic therapeutic target in AS
Late Holocene earthquakes on the Papatea Fault and its role in past earthquake cycles, Marlborough, New Zealand
Publicado dentro del nĂșmero especial "The KaikĆura earthquake", editado por Andrew Nicol, Andy Howell, Nicola Litchfield, Thomas Wilson, Stephen Bannister and Chris Massey.[EN] The north-striking sinistral reverse Papatea Fault ruptured with a very large (up to 12â
m) oblique slip as part of the 2016 MW 7.8 KaikĆura earthquake in the northeastern South Island. Paleoseismic studies were undertaken at three sites along the Papatea Fault, named Murrayâs roadcut, Jacquiâs Gully (both on the main strand), and Wharekiri trench (western strand). These sites provide evidence for up to three Late Holocene paleoearthquakes prior to 2016 (=E0) on this previously unmapped active fault, with preferred OxCal-modelled timings of 98â149 (E1), 546â645 cal yr BP (E2), and >738 cal yr BP (E3). Event correlations between the sites are generally consistent across these past events, implying that the two strands of the Papatea Fault link at depth and rupture together co-seismically as in 2016. Comparisons of its paleoseismic record with the Kekerengu Fault and uplift data from Waipapa Bay and KaikĆura, suggest that the Papatea Fault may have three distinct rupture modes: (i) KaikĆura-type multi-fault ruptures with multi-metre, anelastic block displacements and associated major landscape change; (ii) multi-fault earthquake ruptures with other regional fault combinations; and (iii) single-fault Papatea ruptures with metre-scale displacement. OxCal models offer the possibility that the E1 fault rupture occurred in 1855 CE.Funding was provided through a Natural Hazards Research Platform [grant number 2017-GNS-01-NHRP] to RML and GNS Science MBIE Strategic Science Investment Funding [grant number C05X1702].Peer reviewe
Uncovering Disease Mechanisms in a Novel Mouse Model Expressing Humanized APOEΔ4 and Trem2*R47H.
Late-onset Alzheimer\u27s disease (AD; LOAD) is the most common human neurodegenerative disease, however, the availability and efficacy of disease-modifying interventions is severely lacking. Despite exceptional efforts to understand disease progression via legacy amyloidogenic transgene mouse models, focus on disease translation with innovative mouse strains that better model the complexity of human AD is required to accelerate the development of future treatment modalities. LOAD within the human population is a polygenic and environmentally influenced disease with many risk factors acting in concert to produce disease processes parallel to those often muted by the early and aggressive aggregate formation in popular mouse strains. In addition to extracellular deposits of amyloid plaques and inclusions of the microtubule-associated protein tau, AD is also defined by synaptic/neuronal loss, vascular deficits, and neuroinflammation. These underlying processes need to be better defined, how the disease progresses with age, and compared to human-relevant outcomes. To create more translatable mouse models, MODEL-AD (Model Organism Development and Evaluation for Late-onset AD) groups are identifying and integrating disease-relevant, humanized gene sequences from public databases beginning with APOEΔ4 and Trem2*R47H, two of the most powerful risk factors present in human LOAD populations. Mice expressing endogenous, humanized APOEΔ4 and Trem2*R47H gene sequences were extensively aged and assayed using a multi-disciplined phenotyping approach associated with and relative to human AD pathology. Robust analytical pipelines measured behavioral, transcriptomic, metabolic, and neuropathological phenotypes in cross-sectional cohorts for progression of disease hallmarks at all life stages. In vivo PET/MRI neuroimaging revealed regional alterations in glycolytic metabolism and vascular perfusion. Transcriptional profiling by RNA-Seq of brain hemispheres identified sex and age as the main sources of variation between genotypes including age-specific enrichment of AD-related processes. Similarly, age was the strongest determinant of behavioral change. In the absence of mouse amyloid plaque formation, many of the hallmarks of AD were not observed in this strain. However, as a sensitized baseline model with many additional alleles and environmental modifications already appended, the dataset from this initial MODEL-AD strain serves an important role in establishing the individual effects and interaction between two strong genetic risk factors for LOAD in a mouse host
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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