157 research outputs found
Recommended from our members
The social consequences of minor innovations in construction
Innovation studies in construction focus on a desire to increase economics and efficiency at a large scale. This has resulted in a skewed perspective that sees only major corporations with substantial R&D resources, complex projects, or national interests at the heart of innovation. By adopting anthropological methods, it becomes possible to examine the two aims of this paper: to demonstrate that an accumulation of minor innovations can have significant consequences; and to show that these are inherently social rather than purely economic. Results come from fieldwork studying the improvisatory house-building practices of the Kelabit people of rural Borneo, tracing changes to the technologies used for roofing and foundations, and describes how these are mutually entangled with new social structures. The conclusion is that we should think more broadly about the forms and effects of innovation in construction, and recognise the significance of improvisation at the level of the individual or small group
The Absolute Magnitude of RRc Variables From Statistical Parallax
We present the first definitive measurement of the absolute magnitude of RR
Lyrae c-type variable stars (RRc) determined purely from statistical parallax.
We use a sample of 247 RRc selected from the All Sky Automated Survey (ASAS)
for which high-quality light curves, photometry and proper motions are
available. We obtain high-resolution echelle spectra for these objects to
determine radial velocities and abundances as part of the Carnegie RR Lyrae
Survey (CARRS). We find that M_(V,RRc) = 0.52 +/- 0.11 at a mean metallicity of
[Fe/H] = -1.59. This is to be compared with previous estimates for RRab stars
(M_(V,RRab) = 0.75 +/- 0.13 and the only direct measurement of an RRc absolute
magnitude (RZ Cephei, M_(V, RRc) = 0.27 +/- 0.17). We find the bulk velocity of
the halo to be (W_pi, W_theta, W_z) = (10.9,34.9,7.2) km/s in the radial,
rotational and vertical directions with dispersions (sigma_(W_pi),
sigma_(W_theta), sigma_(W_z)) = (154.7, 103.6, 93.8) km/s. For the disk, we
find (W_pi, W_theta, W_z) = (8.5, 213.2, -22.1) km/s with dispersions
(sigma_(W_pi), sigma_(W_theta), sigma_(W_z)) = (63.5, 49.6, 51.3) km/s.
Finally, we suggest that UCAC2 proper motion errors may be overestimated by
about 25%Comment: Submitted to ApJ. 11 pages including 6 figure
Three Novel Pigmentation Mutants Generated by Genome-Wide Random ENU Mutagenesis in the Mouse
Three mutant mice with pigmentation phenotypes were recovered from a genomewide
random mouse chemical mutagenesis study. White toes (Whto; MGI:1861986),
Belly spot and white toes (Bswt; MGI:2152776) and Dark footpads 2 (Dfp2;
MGI:1861991) were identified following visual inspection of progeny from a male
exposed to the point mutagen ethylnitrosourea (ENU). In order to rapidly localize
the causative mutations, genome-wide linkage scans were performed on pooled
DNA samples from backcross animals for each mutant line. Whto was mapped to
proximal mouse chromosome (Mmu) 7 between Cen (the centromere) and D7Mit112
(8.0 cM from the centromere), Bswt was mapped to centric Mmul between D1Mit214
(32.1 cM) and D1Mit480 (32.8 cM) and Dfp2 was mapped to proximalMmu4 between
Cen and D4Mit18 (5.2 cM). Whto, Bswt and Dfp2 may provide novel starting
points in furthering the elucidation of genetic and biochemical pathways relevant
to pigmentation and associated biological processes
TESS Discovery of an ultra-short-period planet around the nearby M dwarf LHS 3844
Data from the newly-commissioned \textit{Transiting Exoplanet Survey
Satellite} (TESS) has revealed a "hot Earth" around LHS 3844, an M dwarf
located 15 pc away. The planet has a radius of and
orbits the star every 11 hours. Although the existence of an atmosphere around
such a strongly irradiated planet is questionable, the star is bright enough
(, ) for this possibility to be investigated with transit and
occultation spectroscopy. The star's brightness and the planet's short period
will also facilitate the measurement of the planet's mass through Doppler
spectroscopy.Comment: 10 pages, 4 figures. Submitted to ApJ Letters. This letter makes use
of the TESS Alert data, which is currently in a beta test phase, using data
from the pipelines at the TESS Science Office and at the TESS Science
Processing Operations Cente
A System of Three Super Earths Transiting the Late K-Dwarf GJ 9827 at 30 pc
We report the discovery of three small transiting planets orbiting GJ 9827, a bright (K = 7.2) nearby late K-type dwarf star. GJ 9827 hosts a 1.62 ± 0.11 R⊕ super Earth on a 1.2 day period, a 1.269^(+0.087)_(-0.089) R⊕ super Earth on a 3.6 day period, and a 2.07 ± 0.14 R⊕ super Earth on a 6.2 day period. The radii of the planets transiting GJ 9827 span the transition between predominantly rocky and gaseous planets, and GJ 9827 b and c fall in or close to the known gap in the radius distribution of small planets between these populations. At a distance of 30 pc, GJ 9827 is the closest exoplanet host discovered by K2 to date, making these planets well-suited for atmospheric studies with the upcoming James Webb Space Telescope. The GJ 9827 system provides a valuable opportunity to characterize interior structure and atmospheric properties of coeval planets spanning the rocky to gaseous transition
Recommended from our members
A 2 R_⊕ Planet Orbiting the Bright Nearby K Dwarf Wolf 503
Since its launch in 2009, the Kepler telescope has found thousands of planets with radii between that of Earth and Neptune. Recent studies of the distribution of these planets have revealed a gap in the population near 1.5–2.0 R⊕, informally dividing these planets into "super-Earths" and "sub-Neptunes." The origin of this division is difficult to investigate directly because the majority of planets found by Kepler orbit distant, dim stars and are not amenable to radial velocity follow-up or transit spectroscopy, making bulk density and atmospheric measurements difficult. Here, we present the discovery and validation of a newly found 2.03^(+0.08)_(-0.07) R⊕ planet in direct proximity to the radius gap, orbiting the bright (J = 8.32 mag), nearby (D = 44.5 pc) high proper motion K3.5V star Wolf 503 (EPIC 212779563). We determine the possibility of a companion star and false positive detection to be extremely low using both archival images and high-contrast adaptive optics images from the Palomar observatory. The brightness of the host star makes Wolf 503b a prime target for prompt radial velocity follow-up, and with the small stellar radius (0.690 ± 0.025R⊙), it is also an excellent target for HST transit spectroscopy and detailed atmospheric characterization with JWST. With its measured radius near the gap in the planet radius and occurrence rate distribution, Wolf 503b offers a key opportunity to better understand the origin of this radius gap as well as the nature of the intriguing populations of "super-Earths" and "sub-Neptunes" as a whole
A 2 Earth Radius Planet Orbiting the Bright Nearby K-Dwarf Wolf 503
Since its launch in 2009, the Kepler telescope has found thousands of planets
with radii between that of Earth and Neptune. Recent studies of the
distribution of these planets have revealed a rift in the population near
1.5-2.0, informally dividing these planets into "super-Earths"
and "sub-Neptunes". The origin of this division is not well understood, largely
because the majority of planets found by Kepler orbit distant, dim stars and
are not amenable to radial velocity follow-up or transit spectroscopy, making
bulk density and atmospheric measurements difficult. Here, we present the
discovery and validation of a newly found
planet in direct proximity to the radius gap, orbiting the bright
(~mag), nearby (~pc) high proper motion star Wolf 503 (EPIC
212779563). We classify Wolf 503 as a K3.5V star and member of the thick disc
population. We determine the possibility of a companion star and false positive
detection to be extremely low using both archival images and high-contrast
adaptive optics images from the Palomar observatory. The brightness of the host
star makes Wolf 503b a prime target for prompt radial velocity follow-up, HST
transit spectroscopy, as well as detailed atmospheric characterization with
JWST. With its measured radius near the gap in the planet radius and occurrence
rate distribution, Wolf 503b offers a key opportunity to better understand the
origin of this radius gap as well as the nature of the intriguing populations
of "super-Earths" and "sub-Neptunes" as a whole
- …