96 research outputs found
Age and development of active cryoplanation terraces in the alpine permafrost zone at Svartkampan, Jotunheimen, southern Norway
Schmidt-hammer exposure-age dating (SHD) of boulders on cryoplanation terrace treads and associated bedrock cliff faces revealed Holocene ages ranging from 0 ± 825 to 8890 ± 1185 yr. The cliffs were significantly younger than the inner treads, which tended to be younger than the outer treads. Radiocarbon dates from the regolith of 3854 to 4821 cal yr BP (2σ range) indicated maximum rates of cliff recession of ~0.1 mm/year, which suggests the onset of terrace formation prior to the last glacial maximum. Age, angularity and size of clasts, together with planation across bedrock structures and the seepage of groundwater from the cliff foot, all support a process-based conceptual model of cryoplanation terrace development in which frost weathering leads to parallel cliff recession and hence terrace extension. The availability of groundwater during autumn freeze-back is viewed as critical for frost wedging and/or the growth of segregation ice during prolonged winter frost penetration. Permafrost promotes cryoplanation by providing an impermeable frost table beneath the active layer, focusing groundwater flow, and supplying water for sediment transport by solifluction across the tread. Snowbeds are considered an effect rather than a cause of cryoplanation terraces and cryoplanation is seen as distinct from nivation
Vibrio aestuarianus clade A and clade B isolates are associated with Pacific oyster (Magallana gigas) disease outbreaks across Ireland
KELT-1b: A Strongly Irradiated, Highly Inflated, Short Period, 27 Jupiter-mass Companion Transiting a mid-F Star
We present the discovery of KELT-1b, the first transiting low-mass companion
from the wide-field Kilodegree Extremely Little Telescope-North (KELT-North)
survey. The V=10.7 primary is a mildly evolved, solar-metallicity, mid-F star.
The companion is a low-mass brown dwarf or super-massive planet with mass of
27.23+/-0.50 MJ and radius of 1.110+0.037-0.024 RJ, on a very short period
(P=1.21750007) circular orbit. KELT-1b receives a large amount of stellar
insolation, with an equilibrium temperature assuming zero albedo and perfect
redistribution of 2422 K. Upper limits on the secondary eclipse depth indicate
that either the companion must have a non-zero albedo, or it must experience
some energy redistribution. Comparison with standard evolutionary models for
brown dwarfs suggests that the radius of KELT-1b is significantly inflated.
Adaptive optics imaging reveals a candidate stellar companion to KELT-1, which
is consistent with an M dwarf if bound. The projected spin-orbit alignment
angle is consistent with zero stellar obliquity, and the vsini of the primary
is consistent with tidal synchronization. Given the extreme parameters of the
KELT-1 system, we expect it to provide an important testbed for theories of the
emplacement and evolution of short-period companions, and theories of tidal
dissipation and irradiated brown dwarf atmospheres.Comment: 30 pages, 19 figures. Submitted to Ap
KELT-2Ab: A Hot Jupiter Transiting the Bright (V=8.77) Primary Star of a Binary System
We report the discovery of KELT-2Ab, a hot Jupiter transiting the bright
(V=8.77) primary star of the HD 42176 binary system. The host is a slightly
evolved late F-star likely in the very short-lived "blue-hook" stage of
evolution, with \teff=6148\pm48{\rm K}, and
\feh=0.034\pm0.78. The inferred stellar mass is
\msun\ and the star has a relatively large radius
of \rsun. The planet is a typical hot Jupiter with
period days and a mass of \mj\ and
radius of \rj. This is mildly inflated as compared
to models of irradiated giant planets at the 4 Gyr age of the system.
KELT-2A is the third brightest star with a transiting planet identified by
ground-based transit surveys, and the ninth brightest star overall with a
transiting planet. KELT-2Ab's mass and radius are unique among the subset of
planets with host stars, and therefore increases the diversity of bright
benchmark systems. We also measure the relative motion of KELT-2A and -2B over
a baseline of 38 years, robustly demonstrating for the first time that the
stars are bound. This allows us to infer that KELT-2B is an early K-dwarf. We
hypothesize that through the eccentric Kozai mechanism KELT-2B may have
emplaced KELT-2Ab in its current orbit. This scenario is potentially testable
with Rossiter-McLaughlin measurements, which should have an amplitude of
44 m s.Comment: 9 pages, 2 tables, 4 figures. A short video describing this paper is
available at http://www.youtube.com/watch?v=wVS8lnkXXlE. Revised to reflect
the ApJL version. Note that figure 4 is not in the ApJL versio
Measuring sexual behaviours and attitudes in hard-to-reach groups. A comparison of a non-probability web survey with a national probability sample survey
Introduction: Hard-to-reach and minority groups are often at higher risk for adverse sexual health outcomes. While such groups are therefore of interest to sexual health researchers, it can be difficult to locate and recruit sufficient sample sizes using probability sampling methods. This study aims to establish whether web-panel surveys can provide a viable less resource intensive means of boosting sample sizes of two hard-to-reach groups (people of Black African ethnicity, and gay men) for a sexual health survey, and the extent of any bias.
Methods: Results from a national probability sample survey (Natsal-3, administered using a computer-assisted personal interview (CAPI) and self-interview (CASI) with 15,162 participants), which included 211 black African participants and 83 gay men, were compared with results from a web-panel survey (using identical questions) of 529 black Africans and 592 gay men. Web-panel survey results for socio-demographics were compared with external benchmarks, and for sexual behaviours and attitudes reported in Natsal-3. Odds ratios (ORs) were used to examine differences between variables and the average absolute OR, along with the number of estimates for which the web-panel survey differed significantly from the benchmarks, were used to summarise survey performance.
Results: At least 18% of estimates differed significantly between surveys for gay and black African men, and 28% for black African women. For black African women average absolute ORs were: 1.6 for attitudinal questions asked in CAPI, 1.5 for attitudinal CASI questions, 3.2 for behaviour questions asked in CAPI and for 1.7 for behaviour CASI. For black African men average absolute ORs were: 1.5 for attitudinal questions asked in CAPI, 1.8 for attitudinal CASI questions, 2.5 for behavioural questions asked in CAPI and 1.6 for behavioural questions asked in CASI=1.6. For gay men, average absolute ORs were: 2.2 for attitudinal questions asked in CAPI, 2.8 for attitudinal CASI questions, 1.8 for behavioural questions asked in CAPI to 1.6 for behavioural questions asked in CASI.
Discussion: Web-panel surveys may be able to sample hard-to-reach groups but may not be able to replace probability-sample surveys where accurate population-level estimates of sensitive sexual behaviours are required. Differences between web and CASI responses, where mode effects may be similar, suggest web-panel survey selection bias
Starting New Accreditation Council for Graduate Medical Education (ACGME) Residency Programs in a Teaching Hospital
Starting a new ACGME approved residency program can positively impact patient care, medical education, hospital operations, and the community as whole. This requires a significant amount of commitment, time, and preparation. The initial application and accreditation process should start early and requires a thorough understanding on the ACGME requirements. Building a new residency program involves collaboration among various stakeholders, starting with the teaching hospital, ACGME, and the Center of Medicare and Medicaid services (CMS). It is prudent to also consider the operational and logistical issues such as budget, faculty and administrative staff hire, faculty time for administrative duties, and educational space for faculty and residents. It is vital to recognize how the institution’s strengths and weaknesses match up to these requirements. A robust educational and clinical curriculum in line with ACGME’s core competencies and useful educational collaboration among various programs is critical for effective program. Recruiting and developing the appropriate faculty members is another important aspect for a successful program. The final challenge is recruiting residents that will fit well into the new residency program. Lastly, we discuss the challenges and tips to mitigate the risks of disappointment in the process of starting and creating a flagship residency program
Discovery and Rossiter-McLaughlin Effect of Exoplanet Kepler-8b
We report the discovery and the Rossiter-McLaughlin effect of Kepler-8b, a
transiting planet identified by the NASA Kepler Mission. Kepler photometry and
Keck-HIRES radial velocities yield the radius and mass of the planet around
this F8IV subgiant host star. The planet has a radius RP = 1.419 RJ and a mass,
MP = 0.60 MJ, yielding a density of 0.26 g cm^-3, among the lowest density
planets known. The orbital period is P = 3.523 days and orbital semima jor axis
is 0.0483+0.0006/-0.0012 AU. The star has a large rotational v sin i of 10.5
+/- 0.7 km s^-1 and is relatively faint (V = 13.89 mag), both properties
deleterious to precise Doppler measurements. The velocities are indeed noisy,
with scatter of 30 m s^-1, but exhibit a period and phase consistent with the
planet implied by the photometry. We securely detect the Rossiter-McLaughlin
effect, confirming the planet's existence and establishing its orbit as
prograde. We measure an inclination between the projected planetary orbital
axis and the projected stellar rotation axis of lambda = -26.9 +/- 4.6 deg,
indicating a moderate inclination of the planetary orbit. Rossiter-McLaughlin
measurements of a large sample of transiting planets from Kepler will provide a
statistically robust measure of the true distribution of spin-orbit
orientations for hot jupiters in general.Comment: 26 pages, 8 figures, 2 tables; In preparation for submission to the
Astrophysical Journa
Capturing protest in urban environments:The ‘police kettle’ as a territorial strategy
‘Kettling’ has emerged in recent decades as an established, if controversial, tactic of public order policing. Departing from a historical emphasis on dispersal, kettling instead acts to contain protesters within a police cordon for sustained periods of time. This article elaborates upon the spatial and temporal logics of kettling by investigating the conditions of is historical emergence. We argue that kettling should be understood as a territorial strategy that co-evolved in relation to forms of disruptive protest. Whereas techniques of crowd dispersal serve to diffuse a unified collective, ‘kettling’ aims to capture the volatile intensities of public dissent and exhaust its political energies. Drawing on police manuals, media coverage, accounts from activists and expert interviews, we show how the ‘kettle’ re-territorializes protest by acting on its spatio-temporal and affective constitution. By fabricating an inner outside of the urban milieu, freezing the time of collective mobilization and inducing debilitating affects such as fear and boredom, kettling intervenes into the scene of political subjectification that each congregation of protesting bodies seeks to fashion
Synthesis and properties of [Pt(4-CO<sub>2</sub>CH<sub>3</sub>-py)<sub>2</sub>(mnt)]: Comparison of pyridyl and bipyridyl-based dyes for solar cells
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