2,247 research outputs found
Taxonomic Notes on the Ants Ponera leae Forel and Ponera norfolkensis (Wheeler) (Hymenoptera-Formicidae)
Volume: 14Start Page: 178End Page: 18
Analysis of meteorological data from RRS Charles Darwin cruises CD46 and CD47 (BOFS experiment)
The IOSDL MultiMet meteorological instrumentation system was used during the BOFS experiment on RRS Charles Darwin cruises 46 and 47. This report describes and evaluates the quality of the meteorological data obtained. Recommendations for using the data include a 0.45°C correction to the forward dry bulb temperature and the use of wind directions from the main mast wind vane rather than the foremast propellor -vane. The temperature difference between the foremast and wheelhousetop psychrometer measurements was found to be a function of solar radiation and wind speed. A model of this effect was developed. From anemometer comparisons acceleration of the air flow over the ship was estimated to be 4%. The solar radiation sensors
agreed to within a few W/m2 except for anomalous values on two days
Quantum dot emission from site-controlled ngan/gan micropyramid arrays
InxGa1−xN quantum dots have been fabricated by the selective growth of GaN micropyramid arrays topped with InGaN/GaN quantum wells. The spatially, spectrally, and time-resolved emission properties of these structures were measured using cathodoluminescence hyperspectral imaging and low-temperature microphotoluminescence spectroscopy. The presence of InGaN quantum dots was confirmed directly by the observation of sharp peaks in the emission spectrum at the pyramid apices. These luminescence peaks exhibit decay lifetimes of approximately 0.5 ns, with linewidths down to 650 me
Effect of Density Inhomogeneity on YORP: The case of Itokawa
The effect of density inhomogeneity on the YORP effect for a given shape
model is investigated. A density inhomogeneity will cause an offset between the
center of figure and the center of mass and a re-orientation of the principal
axes away from those associated with the shape alone. Both of these effects can
alter the predicted YORP rate of change in angular velocity and obliquity. We
apply these corrections to the Itokawa shape model and find that its YORP
angular velocity rate is sensitive to offsets between its center of mass and
center of figure, with a shift on the order of 10 meters being able to change
the sign of the YORP effect for that asteroid. Given the non-detection of YORP
for Itokawa as of 2008, this can shed light on the density distribution within
that body. The theory supports a shift of the asteroid center of mass towards
Itokawa's neck region, where there is an accumulation of finer gravels.
Detection of the YORP effect for Itokawa should provide some strong constraints
on its density distribution. This theory could also be applied to asteroids
visited by future spacecraft to constrain density inhomogeneities.Comment: 23 pages, 3 figure
Novel POLG variants associated with late-onset de novo status epilepticus and progressive ataxia
Mitochondrial disease is phenotypically and genetically heterogeneous with an estimated prevalence of 1 in 4,300.1 Mutations in the POLG gene, encoding the catalytic subunit of DNA polymerase gamma, are an important cause of mitochondrial disease. The spectrum of clinical manifestations in POLG-related mitochondrial disease is variable,2 with disease onset ranging from adulthood-onset dominant or recessive progressive external ophthalmoplegia (chronic progressive external ophthalmoplegia), ataxia-neuropathy spectrum, myoclonic epilepsy, myopathy, and sensory ataxia to childhood-onset Alpers syndrome, which is characterized by intractable seizures, psychomotor regression, and hepatic impairment. Epilepsy is a poor prognostic factor in POLG mutations,3 and the onset of epilepsy often clusters in childhood (<5 years) and teenage.4 However, late-onset epileptic encephalopathy is uncommon.4,5 Herein, we describe a patient who died of de novo, late-onset refractory status epilepticus with the identification of 2 novel variants in the POLG gene
Exact Numerical Solution of the BCS Pairing Problem
We propose a new simulation computational method to solve the reduced BCS
Hamiltonian based on spin analogy and submatrix diagonalization. Then we
further apply this method to solve superconducting energy gap and the results
are well consistent with those obtained by Bogoliubov transformation method.
The exponential problem of 2^{N}-dimension matrix is reduced to the polynomial
problem of N-dimension matrix. It is essential to validate this method on a
real quantumComment: 7 pages, 3 figure
Pulsar Timing and its Application for Navigation and Gravitational Wave Detection
Pulsars are natural cosmic clocks. On long timescales they rival the
precision of terrestrial atomic clocks. Using a technique called pulsar timing,
the exact measurement of pulse arrival times allows a number of applications,
ranging from testing theories of gravity to detecting gravitational waves. Also
an external reference system suitable for autonomous space navigation can be
defined by pulsars, using them as natural navigation beacons, not unlike the
use of GPS satellites for navigation on Earth. By comparing pulse arrival times
measured on-board a spacecraft with predicted pulse arrivals at a reference
location (e.g. the solar system barycenter), the spacecraft position can be
determined autonomously and with high accuracy everywhere in the solar system
and beyond. We describe the unique properties of pulsars that suggest that such
a navigation system will certainly have its application in future astronautics.
We also describe the on-going experiments to use the clock-like nature of
pulsars to "construct" a galactic-sized gravitational wave detector for
low-frequency (f_GW ~1E-9 - 1E-7 Hz) gravitational waves. We present the
current status and provide an outlook for the future.Comment: 30 pages, 9 figures. To appear in Vol 63: High Performance Clocks,
Springer Space Science Review
Magazine and reader constructions of 'metrosexuality' and masculinity: a membership categorisation analysis
Since the launch of men's lifestyle magazines in the 1980s, academic literature has predominantly focused on them as a cultural phenomenon arising from entrepreneurial and commercial initiatives and/or as cultural texts that proffer representations of masculinity such as 'new lad' and 'new dad'. This paper steps aside from the focus on culture and, instead, treats magazine content as a discursive space in which gender and sexuality are oriented to, negotiated, and accomplished within and beyond the magazine itself (i.e. through readers' responses). Specifically, membership categorisation analysis is deployed to explore how the relatively new (and perhaps alternative) category for men - 'metrosexual' - is presented and received. Our analysis suggests that masculinity concerns are central in debates about 'metrosexuality', with self-identified 'metrosexuals' invoking heterosexual prowess and self-respect on the one hand, and critics (e.g. selfidentified 'real men') lamenting 'metrosexuality' for its perceived effeminacy and lack of authenticity on the other. Implications for understanding contemporary masculinities are discussed
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