411 research outputs found
The Hubble Constant
I review the current state of determinations of the Hubble constant, which
gives the length scale of the Universe by relating the expansion velocity of
objects to their distance. There are two broad categories of measurements. The
first uses individual astrophysical objects which have some property that
allows their intrinsic luminosity or size to be determined, or allows the
determination of their distance by geometric means. The second category
comprises the use of all-sky cosmic microwave background, or correlations
between large samples of galaxies, to determine information about the geometry
of the Universe and hence the Hubble constant, typically in a combination with
other cosmological parameters. Many, but not all, object-based measurements
give values of around 72-74km/s/Mpc , with typical errors of 2-3km/s/Mpc.
This is in mild discrepancy with CMB-based measurements, in particular those
from the Planck satellite, which give values of 67-68km/s/Mpc and typical
errors of 1-2km/s/Mpc. The size of the remaining systematics indicate that
accuracy rather than precision is the remaining problem in a good determination
of the Hubble constant. Whether a discrepancy exists, and whether new physics
is needed to resolve it, depends on details of the systematics of the
object-based methods, and also on the assumptions about other cosmological
parameters and which datasets are combined in the case of the all-sky methods.Comment: Extensively revised and updated since the 2007 version: accepted by
Living Reviews in Relativity as a major (2014) update of LRR 10, 4, 200
Search for Gravitational Waves from Primordial Black Hole Binary Coalescences in the Galactic Halo
We use data from the second science run of the LIGO gravitational-wave
detectors to search for the gravitational waves from primordial black hole
(PBH) binary coalescence with component masses in the range 0.2--.
The analysis requires a signal to be found in the data from both LIGO
observatories, according to a set of coincidence criteria. No inspiral signals
were found. Assuming a spherical halo with core radius 5 kpc extending to 50
kpc containing non-spinning black holes with masses in the range 0.2--, we place an observational upper limit on the rate of PBH coalescence
of 63 per year per Milky Way halo (MWH) with 90% confidence.Comment: 7 pages, 4 figures, to be submitted to Phys. Rev.
Vocal quality description of senile characters from Hollywood movies
PURPOSE: to describe the vocal quality of Hollywood movies characters playing elderly people roles. METHODS: a total of 50 aged character voice samples were used, 11 female and 39 male, from 38 Hollywood movies from the period between 1993 and 2001. Twenty speech therapists performed a perceptual auditory analysis. The listener's task required classifying each character either as elderly or as adult by their speech features, and also assessing their voices following the parameters that are most frequently addressed in the literature as being disordered at an old age. The parameters were hoarseness, vocal fry, breathiness, strain, roughness, vocal weakness, nasal resonance, tremor, vocal modulation, pitch and fundamental frequency stability. RESULTS: after the perceptual auditory analysis we noted that a great number of actors (82%) used senile voices indicating old age, even though not all of them were elderly. The most salient voice set altered was vocal quality (92%), demonstrated by vocal fry (80%), breathiness (54%), strain (38%), hoarseness (30%), and weak voice (28%). The second vocal set most used by the actors for their roles was extensive vocal modulation (44%). It was also observed that vocal instability (64%) was used by the actors. CONCLUSION: it can be concluded from the results that Hollywood movies characterize the elderly characters through evident deviations in vocal quality and modulation, using disordered types of voices and vocal unstable and extensive modulation.OBJETIVO: descrever a qualidade vocal de personagens idosos dos filmes de Hollywood. MÉTODOS: foram colhidas 50 amostras de fala de personagens idosos, 11 do sexo feminino e 39 do masculino, de 38 filmes hollywoodianos dos anos de 1993 a 2001. Através da análise perceptivo-auditiva das amostras de fala, 20 fonoaudiólogos treinados classificaram cada personagem em idoso e não idoso, além de avaliarem as vozes quanto aos seguintes parâmetros citados pela literatura como mais alterados: rouquidão, crepitação, soprosidade, tensão, aspereza, astenia, nasalidade, tremor, modulação, pitch e estabilidade da frequência fundamental. RESULTADOS: após a análise perceptivo-auditiva, foi observado que a grande maioria dos atores (82%) utilizou voz de idoso para representar seus papéis. O marcador mais evidente nas vozes foi alteração na qualidade vocal (92%), demonstrada por crepitação (80%), soprosidade (54%), tensão (38%), rouquidão (30%) e astenia (28%). O segundo marcador mais utilizado pelos atores nas suas representações foi a modulação vocal ampla e variada (44%). Também foram observadas alterações no controle da voz (36%) e instabilidade da frequência fundamental (38%). CONCLUSÃO: a partir dos resultados obtidos pode-se concluir que os filmes de Hollywood caracterizam o idoso através de desvios evidentes na qualidade e modulação da voz, utilizando tipos de vozes alteradas e modulação vocal ampla e instável.Universidade Federal de São Paulo (UNIFESP) Centro de Estudos da VozUNIFESP, Centro de Estudos da VozSciEL
Infestation of shore crab gills by a free-living mussel species
Parasitic and commensal species can impact the structure and function of ecological communities and are typically highly specialized to overcome host defences. Here, we report multiple instances of a normally free-living species, the blue mussel Mytilus edulis Linnaeus, 1758, inhabiting the branchial chamber of the shore crab Carcinus maenas (Linnaeus, 1758) collected from widely separated geographical locations. A total of 127 C. maenas were examined from four locations in the English Channel, one location in the Irish Sea and two locations at the entrance of the Baltic Sea. The branchial chambers of three crabs (one from the English Channel and two from Gullmar Fjord, Sweden) were infested with mussels resembling the genus Mytilus. Sequencing at the Me15/16 locus on the polyphenolic adhesive protein gene confirmed the identity as M. edulis. Bivalve infestation always occurred in larger red male individuals. Up to 16 mussels, ranging from 2 to 11 mm in shell length, were found in each individual, either wedged between gill lamellae or attached to the branchial chamber inner wall. This is one of the first reports of a bivalve inhabiting crustacean gills and is an intriguing case of a normally free-living prey species infesting its predato
A supramolecular helix that disregards chirality
The functions of complex crystalline systems derived from supramolecular biological and non-biological assemblies typically emerge from homochiral programmed primary structures via first principles involving secondary, tertiary and quaternary structures. In contrast, heterochiral and racemic compounds yield disordered crystals, amorphous solids or liquids. Here, we report the self-assembly of perylene bisimide derivatives in a supramolecular helix that in turn self-organizes in columnar hexagonal crystalline domains regardless of the enantiomeric purity of the perylene bisimide. We show that both homochiral and racemic perylene bisimide compounds, including a mixture of 21 diastereomers that cannot be deracemized at the molecular level, self-organize to form single-handed helical assemblies with identical single-crystal-like order. We propose that this high crystalline order is generated via a cogwheel mechanism that disregards the chirality of the self-assembling building blocks. We anticipate that this mechanism will facilitate access to previously inaccessible complex crystalline systems from racemic and homochiral building blocks
Differential glucocorticoid metabolism in patients with persistent versus resolving inflammatory arthritis
Introduction: Impairment in the ability of the inflamed synovium to generate cortisol has been proposed to be a factor in the persistence and severity of inflammatory arthritis. In the inflamed synovium, cortisol is generated from cortisone by the 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme. The objective of this study was to determine the role of endogenous glucocorticoid metabolism in the development of persistent inflammatory arthritis. Methods: Urine samples were collected from patients with early arthritis (symptoms ≤12 weeks duration) whose final diagnostic outcomes were established after clinical follow-up and from patients with established rheumatoid arthritis (RA). All patients were free of disease-modifying anti-rheumatic drugs at the time of sample collection. Systemic measures of glucocorticoid metabolism were assessed in the urine samples by gas chromatography/mass spectrometry. Clinical data including CRP and ESR were also collected at baseline. Results: Systemic measures of 11β-HSD1 activity were significantly higher in patients with early arthritis whose disease went on to persist, and also in the subgroup of patients with persistent disease who developed RA, when compared with patients whose synovitis resolved over time. We observed a significant positive correlation between systemic 11β-HSD1 activity and ESR/CRP in patients with established RA but not in any of the early arthritis patients group. Conclusions: The present study demonstrates that patients with a new onset of synovitis whose disease subsequently resolved had significantly lower levels of systemic 11β-HSD1 activity when compared with patients whose synovitis developed into RA or other forms of persistent arthritis. Low absolute levels of 11β-HSD1 activity do not therefore appear to be a major contributor to the development of RA and it is possible that a high total body 11β-HSD1 activity during early arthritis may reduce the probability of disease resolution
SETD2 loss-of-function promotes renal cancer branched evolution through replication stress and impaired DNA repair
The research leading to these results is supported by Cancer Research UK (XYG, RAB, EG, PM, PE, SG, C Santos, AJR, NM, PAB, AS and C Swanton), Breast Cancer Research Foundation (C Swanton and NK), Medical Research Council (ID: G0902275 to MG and C Santos; ID: G0701935/2 to AJR and C Swanton), the Danish Cancer Society (AMM, J Bartkova and J Bartek), the Lundbeck Foundation (R93-A8990 to J Bartek), the Ministry of the interior of the Czech Republic (grant VG20102014001 to MM and J Bartek), the National Program of Sustainability (grant LO1304 to MM and J Bartek), the Danish Council for Independent Research (grant DFF-1331-00262 to J Bartek), NIHR RMH/ICR Biomedical Research Centre for Cancer (JL), the EC Framework 7 (PREDICT 259303 to XYG, EG, PM, MG, TJ and C Swanton; DDResponse 259892 to J Bartek and J Bartkova and RESPONSIFY ID:259303 to C Swanton), UCL Overseas Research Scholarship (SG). C Swanton is also supported by the European Research Council, Rosetrees Trust and The Prostate Cancer Foundation. This research is supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
Inflammatory regulation of glucocorticoid metabolism in mesenchymal stromal cells
OBJECTIVE: Tissue glucocorticoid levels are regulated by the glucocorticoid activating enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). This enzyme is expressed in cells and tissues arising from mesenchymal stromal cells. Proinflammatory cytokines dramatically increase expression of 11β-HSD1 in stromal cells, an effect implicated in inflammatory arthritis, osteoporosis, obesity and myopathy. Additionally, glucocorticoids act synergistically with pro-inflammatory cytokines to further increase enzyme expression. The mechanisms underlying this regulation are unknown. METHODS: 5' RACE, gene reporter analyses, chemical inhibitors and genetic disruption of intracellular signalling pathways in mouse embryonic fibroblasts (MEFs) were used to define the molecular mechanisms underlying the regulation of 11β-HSD1 expression. RESULTS: 5' RACE, gene reporter and chemical inhibitor studies demonstrated that the increase in 11β-HSD1 expression with TNFα/IL-1β?was via the proximal HSD11B1 gene promoter and depended on NF-κB signalling. These findings were confirmed using MEFs with targeted disruption of NF-κB signalling where RelA(p65) deletion prevented TNFα/IL-1β induction of 11β-HSD1? Glucocorticoids were unable to prevent TNFα-induced NF-κB nuclear translocation. The synergistic enhancement of TNFα-induced 11β-HSD1 expression with glucocorticoids was reproduced by specific inhibitors of p38MAPK. Inhibitor and gene deletion studies indicated that effects of glucocorticoids on p38MAPK activity were primarily through induction of dual specificity MAPK phosphatase-1 (DUSP1) expression. CONCLUSION: The mechanism by which stromal cell expression of 11β-HSD1 is regulated is novel and distinct from that in other tissues. These findings open up new opportunities to inhibit or stimulate local glucocorticoid levels in cells of mesenchymal stromal lineage during inflammation. © 2012 American College of Rheumatology
Baby Food Pouches, Baby-Led Weaning, and Iron Status in New Zealand Infants: An Observational Study.
Iron deficiency in infants can impact development, and there are concerns that the use of baby food pouches and baby-led weaning may impair iron status. First Foods New Zealand (FFNZ) was an observational study of 625 New Zealand infants aged 6.9 to 10.1 months. Feeding methods were defined based on parental reports of infant feeding at "around 6 months of age": "frequent" baby food pouch use (five+ times per week) and "full baby-led weaning" (the infant primarily self-feeds). Iron status was assessed using a venepuncture blood sample. The estimated prevalence of suboptimal iron status was 23%, but neither feeding method significantly predicted body iron concentrations nor the odds of iron sufficiency after controlling for potential confounding factors including infant formula intake. Adjusted ORs for iron sufficiency were 1.50 (95% CI: 0.67-3.39) for frequent pouch users compared to non-pouch users and 0.91 (95% CI: 0.45-1.87) for baby-led weaning compared to traditional spoon-feeding. Contrary to concerns, there was no evidence that baby food pouch use or baby-led weaning, as currently practiced in New Zealand, were associated with poorer iron status in this age group. However, notable levels of suboptimal iron status, regardless of the feeding method, emphasise the ongoing need for paying attention to infant iron nutrition.fals
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