319 research outputs found
Primordial Black Holes as All Dark Matter
We argue that a primordial black hole is a natural and unique candidate for
all dark matter. We show that, in a smooth-hybrid new double inflation model, a
right amount of the primordial black holes, with a sharply-defined mass, can be
produced at the end of the smooth-hybrid regime, through preheating. We first
consider masses < 10^(-7)M_sun which are allowed by all the previous
constraints. We next discuss much heavier mass 10^5 M_sun hinted at by entropy,
and galactic size evolution, arguments. Effects on the running of the scalar
spectral index are computed.Comment: 14 pages, 2 figures, a version to appear in JCAP
Trends in diabetic retinopathy screening attendance and associations with vision impairment attributable to diabetes in a large nationwide cohort
AIMS: To investigate diabetic retinopathy screening attendance and trends in certified vision impairment caused by diabetic eye disease. METHODS: This was a retrospective study of attendance in three urban UK diabetic eye screening programmes in England. A survival analysis was performed to investigate time from diagnosis to first screen by age and sex. Logistic regression analysis of factors influencing screening attendance during a 15-month reporting period was conducted, as well as analysis of new vision impairment certifications (Certificate of Vision Impairment) in England and Wales from 2009 to 2019. RESULTS: Of those newly registered in the Routine Digital Screening pathway (n = 97 048), 80% attended screening within the first 12 months and 88% by 36 months. Time from registration to first eye screening was longer for people aged 18-34 years, and 20% were unscreened after 3 years. Delay in first screen was associated with increased risk of referable retinopathy. Although 95% of participants (n = 291 296) attended during the 15-month reporting period, uptake varied considerably. Younger age, social deprivation, ethnicity and duration of diabetes were independent predictors of non-attendance and referable retinopathy. Although the last 10 years has seen an overall reduction in vision impairment certification attributable to diabetic eye disease, the incidence of vision impairment in those aged <35 years was unchanged. CONCLUSIONS: Whilst the majority of participants are screened in a timely manner, there is considerable variation in uptake. Young adults, have sub-optimal attendance, and levels of vision impairment in this population have not changed over the last 10 years. There is an urgent need to explore barriers to/enablers of attendance in this group to inform policy initiatives and tailored interventions to address this issue
Trends in diabetic retinopathy screening attendance and associations with vision impairment attributable to diabetes in a large nationwide cohort
AIMS: To investigate diabetic retinopathy screening attendance and trends in certified vision impairment caused by diabetic eye disease. METHODS: This was a retrospective study of attendance in three urban UK diabetic eye screening programmes in England. A survival analysis was performed to investigate time from diagnosis to first screen by age and sex. Logistic regression analysis of factors influencing screening attendance during a 15-month reporting period was conducted, as well as analysis of new vision impairment certifications (Certificate of Vision Impairment) in England and Wales from 2009 to 2019. RESULTS: Of those newly registered in the Routine Digital Screening pathway (n = 97 048), 80% attended screening within the first 12 months and 88% by 36 months. Time from registration to first eye screening was longer for people aged 18-34 years, and 20% were unscreened after 3 years. Delay in first screen was associated with increased risk of referable retinopathy. Although 95% of participants (n = 291 296) attended during the 15-month reporting period, uptake varied considerably. Younger age, social deprivation, ethnicity and duration of diabetes were independent predictors of non-attendance and referable retinopathy. Although the last 10 years has seen an overall reduction in vision impairment certification attributable to diabetic eye disease, the incidence of vision impairment in those aged <35 years was unchanged. CONCLUSIONS: Whilst the majority of participants are screened in a timely manner, there is considerable variation in uptake. Young adults, have sub-optimal attendance, and levels of vision impairment in this population have not changed over the last 10 years. There is an urgent need to explore barriers to/enablers of attendance in this group to inform policy initiatives and tailored interventions to address this issue
Procedures for the salvage and necropsy of the Dugong (Dugong Dugon)-second edition 2007
This manual provides a detailed guide for dugong (Dugong dugon) carcass handling and
necropsy procedures. It is intended to be used as a resource and training guide for anyone
involved in dugong incidents including management officers, biologists, parks and wildlife field
staff, and veterinarians and pathologists who may lack dugong expertise. Because of the wide
range of professionals this book is targeting, information and the use of technical terms is
extensive. Section 8.0 provides definitions of various terms used which are italicised throughout
the text
The interstellar medium and feedback in the progenitors of the compact passive galaxies at z~2
Quenched galaxies at z>2 are nearly all very compact relative to z~0,
suggesting a physical connection between high stellar density and efficient,
rapid cessation of star-formation. We present restframe UV spectra of
Lyman-break galaxies (LBGs) at z~3 selected to be candidate progenitors of
quenched galaxies at z~2 based on their compact restframe optical sizes and
high surface density of star-formation. We compare their UV properties to those
of more extended LBGs of similar mass and star formation rate (non-candidates).
We find that candidate progenitors have faster ISM gas velocities and higher
equivalent widths of interstellar absorption lines, implying larger velocity
spread among absorbing clouds. Candidates deviate from the relationship between
equivalent widths of Lyman-alpha and interstellar absorption lines in that
their Lyman-alpha emission remains strong despite high interstellar absorption,
possibly indicating that the neutral HI fraction is patchy such that
Lyman-alpha photons can escape. We detect stronger CIV P-Cygni features
(emission and absorption) and HeII emission in candidates, indicative of larger
populations of metal rich Wolf-Rayet stars compared to non-candidates. The
faster bulk motions, broader spread of gas velocity, and Lyman-alpha properties
of candidates are consistent with their ISM being subject to more energetic
feedback than non-candidates. Together with their larger metallicity (implying
more evolved star-formation activity) this leads us to propose, if
speculatively, that they are likely to quench sooner than non-candidates,
supporting the validity of selection criteria used to identify them as
progenitors of z~2 passive galaxies. We propose that massive, compact galaxies
undergo more rapid growth of stellar mass content, perhaps because the gas
accretion mechanisms are different, and quench sooner than normally-sized LBGs
at these early epochs.Comment: Accepted for publication in the Astrophysical Journa
The Asiago-ESO/RASS QSO Survey. III. Clustering analysis and its theoretical interpretation
This is the third paper of a series describing the Asiago-ESO/RASS QSO survey
(AERQS), a project aimed at the construction of an all-sky statistically
well-defined sample of relatively bright QSOs (B<15) at z<0.3. We present here
the clustering analysis of the full spectroscopically identified database (392
AGN). The clustering signal at 0.02<z<0.22 is detected at a 3-4 sigma level and
its amplitude is measured to be r_0=8.6\pm 2.0 h^{-1} Mpc (in a LambdaCDM
model). The comparison with other classes of objects shows that low-redshift
QSOs are clustered in a similar way to Radio Galaxies, EROs and early-type
galaxies in general, although with a marginally smaller amplitude. The
comparison with recent results from the 2QZ shows that the correlation function
of QSOs is constant in redshift or marginally increasing toward low redshift.
We discuss this behavior with physically motivated models, deriving interesting
constraints on the typical mass of the dark matter halos hosting QSOs, M_DMH=
10^{12.7} h^{-1} M_sun (10^{12.0}-10^{13.5}h^{-1} M_sun at 1 sigma confidence
level). Finally, we use the clustering data to infer the physical properties of
local AGN, obtaining M_BH=2 10^8 h^{-1} M_sun (10^7-3 10^9 h^{-1} M_sun) for
the mass of the active black holes, tau_{AGN}= 8 10^6 yr (2 10^{6}-5 10^{7} yr)
for their life-time and eta = 0.14 for their efficiency (always for a LambdaCDM
model).Comment: 37 pages, Astronomical Journal in press. Changes to match the referee
comment
Observational Limits on Machos in the Galactic Halo
We present final results from the first phase of the EROS search for
gravitational microlensing of stars in the Magellanic Clouds by unseen
deflectors (machos: MAssive Compact Halo Objects). The search is sensitive to
events with time scales between 15 minutes and 200 days corresponding to
deflector masses in the range 1.e-7 to a few solar masses. Two events were
observed that are compatible with microlensing by objects of mass of about 0.1
Mo. By comparing the results with the expected number of events for various
models of the Galaxy, we conclude that machos in the mass range [1.e-7, 0.02]
Mo make up less than 20% (95% C.L.) of the Halo dark matter.Comment: 4 pages, 3 Postscript figures, to be published in Astronomy &
Astrophysic
Segmentação de pele e reconhecimento de gestos para interação humano-computador
This paper presents the development of a new approach to skin segmentation and hand gesture recognition in order to compose applications for Human Computer Interaction requiring real-time computing. Tests performed indicate the possibility of using the approach with low-cost equipment
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