17,914 research outputs found
Lensed CMB power spectra from all-sky correlation functions
Weak lensing of the CMB changes the unlensed temperature anisotropy and
polarization power spectra. Accounting for the lensing effect will be crucial
to obtain accurate parameter constraints from sensitive CMB observations.
Methods for computing the lensed power spectra using a low-order perturbative
expansion are not good enough for percent-level accuracy. Non-perturbative
flat-sky methods are more accurate, but curvature effects change the spectra at
the 0.3-1% level. We describe a new, accurate and fast, full-sky
correlation-function method for computing the lensing effect on CMB power
spectra to better than 0.1% at l<2500 (within the approximation that the
lensing potential is linear and Gaussian). We also discuss the effect of
non-linear evolution of the gravitational potential on the lensed power
spectra. Our fast numerical code is publicly available.Comment: 16 pages, 4 figures. Changes to match PRD version including new
section on non-linear corrections. CAMB code available at http://camb.info
Focus group methodology in a life course approach – individual accounts within a peer cohort group
This paper explores the use of focus group methodology as part of a life course approach building on Julia Brannen’s pioneering work in these two areas. Much life course research uses individual interviews, including biographical interview techniques. It is less usual to find focus groups used within the life course perspective. This paper draws on a PhD study of young British and Asian adults’ experiences of the transition from university to full-time employment, using focus groups as part of a multi-method approach, within a life course perspective. The study drew explicitly on Julia Brannen’s approach to life course transitions. Three focus group excerpts are presented and discussed to illustrate how focus group data can further the understanding of the ways in which a group of peers discuss the transition to work and especially future work–life balance. We show how focus group discussions about individual choice for future work and ‘life’ or ‘lifestyle’ can highlight shared assumptions of this birth cohort group as well as areas of disagreement and contention, rooted in both individual experiences and societal and socio-cultural expectations. We relate this to Julia Brannen’s conceptualisation of the three different modalities which young people draw on to talk about the future
SP-Sephadex equilibrium chromatography of bradykinin and related peptides: Application to trypsin-treated human plasma
An analytical method is deseribed for the separation of bradykinin, Lys-bradykinin, and Met-Lys-bradykinin by equilibrium chromatography on SP-Sephadex C-25 eluted in 0.02 Tris-HCl buffer, pH 8.10, 0.12 NaCl. A second elution buffer, 0.02 Tris-HCl buffer, pH 7.70, 0.06 NaCl, serves as a second parameter for the identification of bradykinin and also separates the hormone from plasma bradykinin-potentiating peptides. Ten to one-hundred nanomoles of each peptide can be recovered in high yields, identified by elution position, and measured by bioassay with the isolated guinea pig ileum. The identification of bradykinin as the peptide released by trypsin acting on acid-denatured plasma is documented as an illustration of the method
AN INDIVIDUALIZED MUSCULOSKELETAL MODEL FOR THE ANALYSIS OF AMPUTEE RUNNING
The purpose of this study was to develop and apply a three-dimensional full body model for the analysis of transtibial amputee athletes. Sprint running was used as an example with a female sprinter as a subject. Data were collected on a running track leading through a biomechanics laboratory with two force platforms in the runway. Inverse dynamics were calculated using a basic and an advanced model, the latter including detailed information on all important muscle groups. Results support what was published on submaximal running with regard to joint moments and power. The muscle model revealed highly asymmetric muscle forces around the hip joint which may explain the overuse injuries some of these runners experience. Future research is needed to improve the individualisation of the modeling approach
Combining DLC, Shot blasting, chemical dip and nano fullerene surface treatments to reduce wear and friction when used with bio-lubricants in automotive contacts
The interaction of three bio-lubricant base oil candidates with seventeen combinations of surface treatment was studied, comparing wear scar volumes and coefficient of friction results. Substrates were initially ground, then a combination of superfinished, Dymon-iC™ DLC, an impact technique of ultra-fine shot blasting method doped with Tin and Molybdenum Disulfide, a calcium based chemical dip containing calcium sulfate and nano fullerene, were used.DLC is well reported to reduce friction. Some reports suggest wear in coated contacts is independent of the type of lubricant used, whilst others report that bio-lubricants offer reduced friction and wear in combination with DLC. Shot blasting can also reduce wear and friction, due to the surface dimples acting as lubricant reservoirs, making hydrodynamic lubrication more likely. Previous work has also explored the performance of surface texturing in combination with coatings, some reporting higher friction when surface texturing and DLC is used. As a surface coating, fullerene has been shown to have significantly lower wear and friction than DLC coatings. The calcium based chemical treatment used has no published data.A ball on flat reciprocating wear tester was used with bio-lubricant base oil candidates, jojoba and soybean oil, with a mineral base oil used for comparison. Wear scars were analysed using a scanning electron microscope.Coefficient of friction results from testing with bio-lubricant base oil candidates’ soybean and jojoba oil were lower than tests with mineral base oil. A hybridized coating combination of superfinish, diamond like carbon and chemical dip gave the highest wear protection for tests with the mineral base oil and bio-lubricant base oil candidate soybean oil. A hybridized coating combination of superfinish, impact technique and chemical dip gave highest wear protection when tested with bio-lubricant base oil candidate jojoba oil. Results showed no overall improvement in wear protection when substrates were processed with the impact technique. Superfinishing substrates improved the performance of both the chemical dip and DLC
Comparisons of trace constituents from ground stations and the DC-8 aircraft during PEM-West B
Chemical data from ground stations in Asia and the North Pacific are compared with data from the DC-8 aircraft collected during the Pacific Exploratory Measurements in the Western Pacific Ocean (PEM-West B) mission. Ground station sampling took place on Hong Kong, Taiwan, Okinawa, and Cheju; and at three Pacific islands, Shemya, Midway, and Oahu. Aircraft samples were collected during 19 flights, most over the western North Pacific. Aluminum was used as an indicator of mineral aerosol, and even though the aircraft did sample Asian dust, strong dust storms were not encountered. The frequency distribution for non-sea-salt sulfate (nss SO4=) in the aircraft samples was bimodal: the higher concentration mode (∼1 μg m−3) evidently originated from pollution or, less likely, from volcanic sources, while the lower mode, with a peak at 0.040 μg m−3, probably was a product of biogenic emissions. In addition, the concentrations of aerosol sulfate varied strongly in the vertical: arithmetic mean SO4=concentrations above 5000 m ( = 0.21±0.69 μg m−3) were substantially lower than those below ( = 1.07±0.87 μg m−3), suggesting the predominance of the surface sources. Several samples collected in the stratosphere exhibited elevated SO4=, however, probably as a result of emissions from Mount Pinatubo. During some boundary layer legs on the DC-8, the concentrations of CO and O3 were comparable to those of clean marine air, but during other legs, several chemically distinct air masses were sampled, including polluted air in which O3was photochemically produced. In general, the continental outflow sampled from the aircraft was substantially diluted with respect to what was observed at the ground stations. Higher concentrations of aerosol species, O3, and CO at the Hong Kong ground station relative to the aircraft suggest that much of the continental outflow from southeastern Asia occurs in the lower troposphere, and extensive long-range transport out of this part of Asia is not expected. In comparison, materials emitted farther to the north apparently are more susceptible to long-range transport
Visions in monochrome: Families, marriage and the individualisation thesis
This paper takes issue with the way in which the individualisation thesis – in which it is assumed that close relationships have become tenuous and fragile - has become so dominant in ‘new’ sociological theorising about family life. Although others have criticised this thesis, in this paper the main criticism derives from empirical research findings carried out with members of transnational families living in Britain whose values and practices do not fit easily with ideas of individualisation. It is argued that we need a much more complex and less linear notion of how families change across generations and in time
Testing Mode-Coupling Theory for a Supercooled Binary Lennard-Jones Mixture II: Intermediate Scattering Function and Dynamic Susceptibility
We have performed a molecular dynamics computer simulation of a supercooled
binary Lennard-Jones system in order to compare the dynamical behavior of this
system with the predictions of the idealized version of mode-coupling theory
(MCT). By scaling the time by the temperature dependent -relaxation
time , we find that in the -relaxation regime and
, the coherent and incoherent intermediate scattering functions, for
different temperatures each follows a -dependent master curve as a function
of scaled time. We show that during the early part of the -relaxation,
which is equivalent to the late part of the -relaxation, these master
curves are well approximated by the master curve predicted by MCT for the
-relaxation. This part is also fitted well by a power-law, the so-called
von Schweidler law. We show that the effective exponent of this power-law
depends on the wave vector if is varied over a large range. The early
part of the -relaxation regime does not show the critical decay
predicted by MCT. The -dependence of the nonergodicity parameter for
and are in qualitative agreement with MCT. On the time
scale of the late -relaxation the correlation functions show a
Kohlrausch-Williams-Watt behavior (KWW). The KWW exponent is
significantly different from the effective von Schweidler exponent . At low
temperatures the -relaxation time shows a power-law behavior
with a critical temperature that is the same as the one found previously for
the diffusion constant [Phys. Rev. Lett. {\bf 73}, 1376 (1994)]. The critical
exponent of this power-law and the von Schweidler exponent fulfill the
connection proposed by MCT between these two quantities. We also show that theComment: 28 Pages of REVTEX, Figures available from W. Ko
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