157 research outputs found
ADIPLS -- the Aarhus adiabatic oscillation package
Development of the Aarhus adiabatic pulsation code started around 1978.
Although the main features have been stable for more than a decade, development
of the code is continuing, concerning numerical properties and output. The code
has been provided as a generally available package and has seen substantial use
at a number of installations. Further development of the package, including
bringing the documentation closer to being up to date, is planned as part of
the HELAS Coordination Action.Comment: Astrophys. Space Sci., in the pres
Body Fixed Frame, Rigid Gauge Rotations and Large N Random Fields in QCD
The "body fixed frame" with respect to local gauge transformations is
introduced. Rigid gauge "rotations" in QCD and their \Sch equation are studied
for static and dynamic quarks. Possible choices of the rigid gauge field
configuration corresponding to a nonvanishing static colormagnetic field in the
"body fixed" frame are discussed. A gauge invariant variational equation is
derived in this frame. For large number N of colors the rigid gauge field
configuration is regarded as random with maximally random probability
distribution under constraints on macroscopic--like quantities. For the uniform
magnetic field the joint probability distribution of the field components is
determined by maximizing the appropriate entropy under the area law constraint
for the Wilson loop. In the quark sector the gauge invariance requires the
rigid gauge field configuration to appear not only as a background but also as
inducing an instantaneous quark-quark interaction. Both are random in the large
N limit.Comment: 29 pages LATEX, Weizmann Institute preprint WIS-93/40/Apr -P
Nonperturbative Renormalization and the QCD Vacuum
We present a self consistent approach to Coulomb gauge Hamiltonian QCD which
allows one to relate single gluon spectral properties to the long range
behavior of the confining interaction. Nonperturbative renormalization is
discussed. The numerical results are in good agreement with phenomenological
and lattice forms of the static potential.Comment: 23 pages in RevTex, 4 postscript figure
The position of graptolites within Lower Palaeozoic planktic ecosystems.
An integrated approach has been used to assess the palaeoecology of graptolites both as a discrete group and also as a part of the biota present within Ordovician and Silurian planktic realms. Study of the functional morphology of graptolites and comparisons with recent ecological analogues demonstrates that graptolites most probably filled a variety of niches as primary consumers, with modes of life related to the colony morphotype. Graptolite coloniality was extremely ordered, lacking any close morphological analogues in Recent faunas. To obtain maximum functional efficiency, graptolites would have needed varying degrees of coordinated automobility. A change in lifestyle related to ontogenetic changes was prevalent within many graptolite groups. Differing lifestyle was reflected by differing reproductive strategies, with synrhabdosomes most likely being a method for rapid asexual reproduction. Direct evidence in the form of graptolithophage 'coprolitic' bodies, as well as indirect evidence in the form of probable defensive adaptations, indicate that graptolites comprised a food item for a variety of predators. Graptolites were also hosts to a variety of parasitic organisms and provided an important nutrient source for scavenging organisms
The Hamiltonian limit of (3+1)D SU(3) lattice gauge theory on anisotropic lattices
The extreme anisotropic limit of Euclidean SU(3) lattice gauge theory is
examined to extract the Hamiltonian limit, using standard path integral Monte
Carlo (PIMC) methods. We examine the mean plaquette and string tension and
compare them to results obtained within the Hamiltonian framework of Kogut and
Susskind. The results are a significant improvement upon previous Hamiltonian
estimates, despite the extrapolation procedure necessary to extract
observables. We conclude that the PIMC method is a reliable method of obtaining
results for the Hamiltonian version of the theory. Our results also clearly
demonstrate the universality between the Hamiltonian and Euclidean formulations
of lattice gauge theory. It is particularly important to take into account the
renormalization of both the anisotropy, and the Euclidean coupling ,
in obtaining these results.Comment: 10 pages, 11 figure
ASTEC -- the Aarhus STellar Evolution Code
The Aarhus code is the result of a long development, starting in 1974, and
still ongoing. A novel feature is the integration of the computation of
adiabatic oscillations for specified models as part of the code. It offers
substantial flexibility in terms of microphysics and has been carefully tested
for the computation of solar models. However, considerable development is still
required in the treatment of nuclear reactions, diffusion and convective
mixing.Comment: Astrophys. Space Sci, in the pres
Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) and the direct CP asymmetry in B0 -> K*0 gamma
The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma
and Bs0 phi gamma has been measured using an integrated luminosity of 1.0 fb-1
of pp collision data collected by the LHCb experiment at a centre-of-mass
energy of sqrt(s)=7 TeV. The value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 ->
phi gamma) = 1.23 +/- 0.06(stat.) +/- 0.04(syst.) +/- 0.10(fs/fd), where the
first uncertainty is statistical, the second is the experimental systematic
uncertainty and the third is associated with the ratio of fragmentation
fractions fs/fd. Using the world average value for BR(B0 -> K*0 gamma), the
branching fraction BR(Bs0 -> phi gamma) is measured to be (3.5 +/- 0.4) x
10^{-5}.
The direct CP asymmetry in B0 -> K*0 gamma decays has also been measured with
the same data and found to be A(CP)(B0 -> K*0 gamma) = (0.8 +/- 1.7(stat.) +/-
0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the
previous experimental results and theoretical expectations.Comment: 21 pages, 3 figues, 4 table
Detection of long repeat expansions from PCR-free whole-genome sequence data
Identifying large expansions of short tandem repeats (STRs) such as those that cause amyotrophic lateral sclerosis (ALS) and fragile X syndrome is challenging for short-read whole-genome sequencing (WGS) data. A solution to this problem is an important step towards integrating WGS into precision medicine. We have developed a software tool called ExpansionHunter that, using PCR-free WGS short-read data, can genotype repeats at the locus of interest, even if the expanded repeat is larger than the read length. We applied our algorithm to WGS data from 3,001 ALS patients who have been tested for the presence of the C9orf72 repeat expansion with repeat-primed PCR (RP-PCR). Compared against this truth data, ExpansionHunter correctly classified all (212/212, 95% CI [0.98, 1.00]) of the expanded samples as either expansions (208) or potential expansions (4). Additionally, 99.9% (2,786/2,789, 95% CI [0.997, 1.00]) of the wild type samples were correctly classified as wild type by this method with the remaining three samples identified as possible expansions. We further applied our algorithm to a set of 152 samples where every sample had one of eight different pathogenic repeat expansions including those associated with fragile X syndrome, Friedreich's ataxia and Huntington's disease and correctly flagged all but one of the known repeat expansions. Thus, ExpansionHunter can be used to accurately detect known pathogenic repeat expansions and provides researchers with a tool that can be used to identify new pathogenic repeat expansions. The software is licensed under GPL v3.0 and the source code is freely available on GitHub
Stepped fans and facies-equivalent phyllosilicates in Coprates Catena, Mars
Stepped fan deposits and phyllosilicate mineralogies are relatively common features on Mars but have not previously been found in association with each other. Both of these features are widely accepted to be the result of aqueous processes, but the assumed role and nature of any water varies. In this study we have investigated two stepped fan deposits in Coprates Catena, Mars, which have a genetic link to light-toned material that is rich in FeâMg phyllosilicate phases. Although of different sizes and in separate, but adjacent, trough-like depressions, we identify similar features at these stepped fans and phyllosilicates that are indicative of similar formation conditions and processes. Our observations of the overall geomorphology, mineralogy and chronology of these features are consistent with a two stage formation process, whereby deposition in the troughs first occurs into shallow standing water or playas, forming fluvial or alluvial fans that terminate in delta deposits and interfinger with interpreted lacustrine facies, with a later period of deposition under sub-aerial conditions, forming alluvial fan deposits. We suggest that the distinctive stepped appearance of these fans is the result of aeolian erosion, and is not a primary depositional feature. This combined formation framework for stepped fans and phyllosilicates can also explain other similar features on Mars, and adds to the growing evidence of fluvial activity in the equatorial region of Mars during the Hesperian and Amazonian
A Historiometric Examination of Machiavellianism and a New Taxonomy of Leadership
Although researchers have extensively examined the relationship between charismatic leadership and Machiavellianism (Deluga, 2001; Gardner & Avolio, 1995; House & Howell, 1992), there has been a lack of investigation of Machiavellianism in relation to alternative forms of outstanding leadership. Thus, the purpose of this investigation was to examine the relationship between Machiavellianism and a new taxonomy of outstanding leadership comprised of charismatic, ideological, and pragmatic leaders. Using an historiometric approach, raters assessed Machiavellianism via the communications of 120 outstanding leaders in organizations across the domains of business, political, military, and religious institutions. Academic biographies were used to assess twelve general performance measures as well as twelve general controls and five communication specific controls. The results indicated that differing levels of Machiavellianism is evidenced across the differing leader types as well as differing leader orientation. Additionally, Machiavellianism appears negatively related to performance, though less so when type and orientation are taken into account.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
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