2,451 research outputs found
Non-Gaussianity detections in the Bianchi VIIh corrected WMAP 1-year data made with directional spherical wavelets
Many of the current anomalies reported in the Wilkinson Microwave Anisotropy
Probe (WMAP) 1-year data disappear after `correcting' for the best-fit embedded
Bianchi type VII_h component (Jaffe et al. 2005), albeit assuming no dark
energy component. We investigate the effect of this Bianchi correction on the
detections of non-Gaussianity in the WMAP data that we previously made using
directional spherical wavelets (McEwen et al. 2005a). As previously discovered
by Jaffe et al. (2005), the deviations from Gaussianity in the kurtosis of
spherical Mexican hat wavelet coefficients are eliminated once the data is
corrected for the Bianchi component. This is due to the reduction of the cold
spot at Galactic coordinates (l,b)=(209^\circ,-57\circ), which Cruz et al.
(2005) claim to be the source of non-Gaussianity introduced in the kurtosis.
Our previous detections of non-Gaussianity observed in the skewness of
spherical wavelet coefficients are not reduced by the Bianchi correction.
Indeed, the most significant detection of non-Gaussianity made with the
spherical real Morlet wavelet at a significant level of 98.4% remains (using a
very conservative method to estimate the significance). We make our code to
simulate Bianchi induced temperature fluctuations publicly available.Comment: 11 pages, 8 figures, replaced to match version accepted by MNRA
From Feynman Proof of Maxwell Equations to Noncommutative Quantum Mechanics
In 1990, Dyson published a proof due to Feynman of the Maxwell equations
assuming only the commutation relations between position and velocity. With
this minimal assumption, Feynman never supposed the existence of Hamiltonian or
Lagrangian formalism. In the present communication, we review the study of a
relativistic particle using ``Feynman brackets.'' We show that Poincar\'e's
magnetic angular momentum and Dirac magnetic monopole are the consequences of
the structure of the Lorentz Lie algebra defined by the Feynman's brackets.
Then, we extend these ideas to the dual momentum space by considering
noncommutative quantum mechanics. In this context, we show that the
noncommutativity of the coordinates is responsible for a new effect called the
spin Hall effect. We also show its relation with the Berry phase notion. As a
practical application, we found an unusual spin-orbit contribution of a
nonrelativistic particle that could be experimentally tested. Another practical
application is the Berry phase effect on the propagation of light in
inhomogeneous media.Comment: Presented at the 3rd Feynman Festival (Collage Park, Maryland,
U.S.A., August 2006
Metabolic and hormonal studies of Type 1 (insulin-dependent) diabetic patients after successful pancreas and kidney transplantation
Long-term normalization of glucose metabolism is necessary to prevent or ameliorate diabetic complications. Although pancreatic grafting is able to restore normal blood glucose and glycated haemoglobin, the degree of normalization of the deranged diabetic metabolism after pancreas transplantation is still questionable. Consequently glucose, insulin, C-peptide, glucagon, and pancreatic polypeptide responses to oral glucose and i.v. arginine were measured in 36 Type 1 (insulin-dependent) diabetic recipients of pancreas and kidney allografts and compared to ten healthy control subjects. Despite normal HbA1 (7.2±0.2%; normal <8%) glucose disposal was normal only in 44% and impaired in 56% of the graft recipients. Normalization of glucose tolerance was achieved at the expense of hyperinsulinaemia in 52% of the subjects. C-peptide and glucagon were normal, while pancreatic polypeptide was significantly higher in the graft recipients. Intravenous glucose tolerance (n=21) was normal in 67% and borderline in 23%. Biphasic insulin release was seen in patients with normal glucose tolerance. Glucose tolerance did not deteriorate up to 7 years post-transplant. In addition, stress hormone release (cortisol, growth hormone, prolactin, glucagon, catecholamines) to insulin-induced hypoglycaemia was examined in 20 graft recipients and compared to eight healthy subjects. Reduced blood glucose decline indicates insulin resistance, but glucose recovery was normal, despite markedly reduced catecholamine and glucagon release. These data demonstrate the effectiveness of pancreatic grafting in normalizing glucose metabolism, although hyperinsulinaemia and deranged counterregulatory hormone response are observed frequently
Non-deterministic density classification with diffusive probabilistic cellular automata
We present a probabilistic cellular automaton (CA) with two absorbing states
which performs classification of binary strings in a non-deterministic sense.
In a system evolving under this CA rule, empty sites become occupied with a
probability proportional to the number of occupied sites in the neighborhood,
while occupied sites become empty with a probability proportional to the number
of empty sites in the neighborhood. The probability that all sites become
eventually occupied is equal to the density of occupied sites in the initial
string.Comment: 4 pages, 4 figure
Cosmic Microwave Background, Accelerating Universe and Inhomogeneous Cosmology
We consider a cosmology in which a spherically symmetric large scale
inhomogeneous enhancement or a void are described by an inhomogeneous metric
and Einstein's gravitational equations. For a flat matter dominated universe
the inhomogeneous equations lead to luminosity distance and Hubble constant
formulas that depend on the location of the observer. For a general
inhomogeneous solution, it is possible for the deceleration parameter to differ
significantly from the FLRW result. The deceleration parameter can be
interpreted as ( for a flat matter dominated universe) in a
FLRW universe and be as inferred from the inhomogeneous enhancement
that is embedded in a FLRW universe. A spatial volume averaging of local
regions in the backward light cone has to be performed for the inhomogeneous
solution at late times to decide whether the decelerating parameter can be
negative for a positive energy condition. The CMB temperature fluctuations
across the sky can be unevenly distributed in the northern and southern
hemispheres in the inhomogeneous matter dominated solution, in agreement with
the analysis of the WMAP power spectrum data by several authors. The model can
possibly explain the anomalous alignment of the quadrupole and octopole moments
observed in the WMAP data.Comment: 20 pages, no figures, LaTex file. Equations and typos corrected and
references added. Additional material and some conclusions changed. Final
published versio
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The programming of sequences of saccades
Saccadic eye movements move the high-resolution fovea to point at regions of interest. Saccades can only be generated serially (i.e., one at a time). However, what remains unclear is the extent to which saccades are programmed in parallel (i.e., a series of such moments can be planned together) and how far ahead such planning occurs. In the current experiment, we investigate this issue with a saccade contingent preview paradigm. Participants were asked to execute saccadic eye movements in response to seven small circles presented on a screen. The extent to which participants were given prior information about target locations was varied on a trial-by-trial basis: participants were aware of the location of the next target only, the next three, five, or all seven targets. The addition of new targets to the display was made during the saccade to the next target in the sequence. The overall time taken to complete the sequence was decreased as more targets were available up to all seven targets. This was a result of a reduction in the number of saccades being executed and a reduction in their saccade latencies. Surprisingly, these results suggest that, when faced with a demand to saccade to a large number of target locations, saccade preparation about all target locations is carried out in paralle
Complete genome sequence of the Medicago microsymbiont Ensifer (Sinorhizobium) medicae strain WSM419
Ensifer (Sinorhizobium) medicae is an effective nitrogen fixing microsymbiont of a diverse range of annual Medicago (medic) species. Strain WSM419 is an aerobic, motile, non-spore forming, Gram-negative rod isolated from a M. murex root nodule collected in Sardinia, Italy in 1981. WSM419 was manufactured commercially in Australia as an inoculant for annual medics during 1985 to 1993 due to its nitrogen fixation, saprophytic competence and acid tolerance properties. Here we describe the basic features of this organism, together with the complete genome sequence, and annotation. This is the first report of a complete genome se-quence for a microsymbiont of the group of annual medic species adapted to acid soils. We reveal that its genome size is 6,817,576 bp encoding 6,518 protein-coding genes and 81 RNA only encoding genes. The genome contains a chromosome of size 3,781,904 bp and 3 plasmids of size 1,570,951 bp, 1,245,408 bp and 219,313 bp. The smallest plasmid is a fea-ture unique to this medic microsymbiont
The New ‘Hidden Abode’: Reflections on Value and Labour in the New Economy
In a pivotal section of Capital, volume 1, Marx (1976: 279) notes that, in order to understand the capitalist production of value, we must descend into the ‘hidden abode of production’: the site of the labour process conducted within an employment relationship. In this paper we argue that by remaining wedded to an analysis of labour that is confined to the employment relationship, Labour Process Theory (LPT) has missed a fundamental shift in the location of value production in contemporary capitalism. We examine this shift through the work of Autonomist Marxists like Hardt and Negri, Lazaratto and Arvidsson, who offer theoretical leverage to prize open a new ‘hidden abode’ outside employment, for example in the ‘production of organization’ and in consumption. Although they can open up this new ‘hidden abode’, without LPT's fine-grained analysis of control/resistance, indeterminacy and structured antagonism, these theorists risk succumbing to empirically naive claims about the ‘new economy’. Through developing an expanded conception of a ‘new hidden abode’ of production, the paper demarcates an analytical space in which both LPT and Autonomist Marxism can expand and develop their understanding of labour and value production in today's economy. </jats:p
Preparing to work: dramaturgy, cynicism and normative ‘remote’ control in the socialization of graduate recruits in management consulting
online) This paper examines the socialization of graduate recruits into a knowledge intensive labour
process and organizational culture. Theoretically the paper draws upon the idea of ‘preparing
for work’ to position this early socialization as a crucial moment in the production of
subjectivities suited (and booted) for the labour process of management consulting. Empirically
the paper reports on a two-day induction session for new graduate recruits joining a global
management consultancy and their responses to this training. Particular attention is given to
the use of role-play and a dramaturgical workshop used in part of the training process. The paper
argues that the utilization of dramaturgy in training is consistent with the overall approach to
control developed in the firm in response to the fact that the labour process of consulting is
often conducted on client sites, away from any direct supervisory gaze. As such, the consultants
were subjected to a form of cultural control that was designed to function independently of
direct supervision. This control did not operate directly upon the new employees professed
values, however, but at one step removed so that a ‘cynical distance’ from the content of the
organization’s culture was accepted so long as a professional ‘ethic of behaviour’ was
established. By focusing on an ‘ethic of behaviour’ these young professionals were encouraged
to internalize a self-control akin to that of an actor, rather than internalizing the corporate values
entirely
THERMAL DENATURATION OF MONOMERIC AND TRIMERIC PHYCOCYANINS STUDIED BY STATIC AND SPECTROSCOPY POLARIZED TIME-RESOLVED FLUORESCENCE
C-Phycocyanin (PC) and allophycocyanin (APC). as well as the a-subunit of PC. have been
isolated from the blue-green alga (cyanobacterium). Spirulina platensis. The effects of partial thermal
denaturation of PC and of its state of aggregation have been studied by ps time-resolved, polarized
fluorescence spectroscopy. All measurements have been performed under low photon fluxes (< 10’ ’
photonsipulse x cm’) to minimize singlet-singlet annihilation processes. A complex decay is obtained
under most conditions, which can be fitted satisfactorily with a bi-exponential (7’ = 70400 ps. T? =
1000-3000 ps) for both the isotropic and the polarized part, but with different intensities and time
constants for the two decay curves. The data are interpreted in the frameworkof the model first developed
by Teak and Dale (Biochern. J. 116, 161 (1970)], which divides the spectroscopically different
chromophores in (predominantly) sensitizing (s) and fluorescing U, ones. If one assumes temperature
dependent losses in the energy transfer from the s to the f and between f chromophores. both the
biexponential nature of the isotropic fluorescence decay and the polarization data can be rationalized. In
the isotropic emission (corresponding to the population of excited states) the short lifetime is related to the
s-,f transfer. the longer one to the “free“ decay of the final acceptor(s) (= f). The polarized part is
dominated by an extremely short decay time. which is related to s+f transfer, as well as to resonance
transfer between the f-chromophores
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