160 research outputs found
corr2D: Implementation of Two-Dimensional Correlation Analysis in R
In the package corr2D two-dimensional correlation analysis is implemented in R. This paper describes how two-dimensional correlation analysis is done in the package and how the mathematical equations are translated into R code. The paper features a simple tutorial with executable code for beginners, insight into the calculations done before the correlation analysis, a detailed look at the parallelization of the fast Fourier transformation based correlation analysis and a speed test of the calculation. The package corr2D offers the possibility to preprocess, correlate and postprocess spectroscopic data using exclusively the R language. Thus, corr2D is a welcome addition to the toolbox of spectroscopists and makes two-dimensional correlation analysis more accessible and transparent
A PCR Survey of Xenoturbella bocki Hox Genes
Xenoturbella bocki has recently been identified as one of the most basal deuterostomes, although an even more basal phylogenetic position cannot be ruled out. Here we report on a polymerase chain reaction survey of partial Hox homeobox sequences of X. bocki. Surprisingly, we did not find evidence for more than five Hox genes, one clear labial/PG1 ortholog, one posterior gene most similar to the PG9/10 genes of Ambulacraria, and three central group genes whose precise assignment to a specific paralog group remains open. We furthermore report on a re‐evaluation of the available published evidence of Hox genes in other basal deuterostomes
Quark Mass Ratios and Mixing Angles from SU(3) Family Gauge Symmetry
We explore a framework for the computation of quark mass ratios and CKM
mixing angles based on an SU(3) family gauge symmetry. The four ratios md/mb,
ms/mb, mu/mt, and mc/mt can be fit at one-loop in the family gauge interaction.
The same is true of the quark mixing angles theta12 and theta23, although the
result for theta13 is too small. The CP violating phase is naturally O(1).Comment: 6 pages, 1 table, small corrections, added reference
The mitochondrial DNA of Xenoturbella bocki: genomic architecture and phylogenetic analysis
The phylogenetic position of Xenoturbella bocki has been a matter of controversy since its description in 1949. We sequenced a second complete mitochondrial genome of this species and performed phylogenetic analyses based on the amino acid sequences of all 13 mitochondrial protein-coding genes and on its gene order. Our results confirm the deuterostome relationship of Xenoturbella. However, in contrast to a recently published study (Bourlat et al. in Nature 444:85–88, 2006), our data analysis suggests a more basal branching of Xenoturbella within the deuterostomes, rather than a sister-group relationship to the Ambulacraria (Hemichordata and Echinodermata)
A realistic formulation of approximate CP
CP violation in the SM is naturally implemented as a small imaginary
perturbation to real Yukawa couplings. For example, a large CP asymmetry in B_d
decays can arise if the imaginary parts of quark mass matrices are of order
10^(-3)m_t,b or smaller. Applying the same principle of ``additive CP
violation'' to soft SUSY-breaking terms, the electric dipole moments of the
neutron and mercury atom are predicted near current experimental limits; for
nonuniversal A-terms, EDM bounds can be satisfied given certain flavour
structures. The proposal is conveniently formulated in a democratic basis, with
Yukawas and soft terms of the form const. x (1+eps+i zeta) where eps<<1,
zeta<~10^(-3), motivated by approximate permutation x CP symmetry.Comment: 28 pages, 2 tables v3: improved notation and discussion of
'removability' v2: revised discussion of USY, improved notation of SUSY
section, added acknowledgements and reference
Consequences of Triplet Seesaw for Leptogenesis
We present the various leptogenesis scenarios which may occur if, in addition
to the ordinary heavy right-handed neutrinos, there exists a heavy scalar
SU(2)_L triplet coupled to leptons. We show that the contributions of the
right-handed neutrinos and the triplet to the lepton asymmetry are proportional
to their respective contributions to the neutrino mass matrix. A consequence of
the triplet contribution to the lepton asymmetry is that there is no more upper
bound on the neutrino masses from leptogenesis due to the fact that the
neutrino mass constraints do not necessarily induce asymmetry washout effects.
We also show how such a triplet leptogenesis mechanism may emerge naturally in
the framework of the left-right symmetric theories, such as Pati-Salam or
SO(10).Comment: 13 pages; references added, 2 footnotes modifie
Are Two Gluons the QCD Pomeron?
Collider experiments have recently measured the production cross section of
hard jets separated by a rapidity gap as a function of transverse momentum and
gap size. We show that these measurements reveal the relative frequencies for
the production of rapidity gaps in quark-quark, quark-gluon and gluon-gluon
interactions. The results are at variance with the idea that the exchange of 2
gluons is a first order approximation for the mechanism producing colorless
states, i.e. the hard QCD Pomeron. They do qualitatively support the "soft
color" or "color evaporation" scheme developed in the context of bound-state
heavy quark production.Comment: 17 pages, Latex 2.09, uses epsfig.sty, 10 postscript files include
Towards a Quality Indicator for Research Data publications and Research Software publications -- A vision from the Helmholtz Association
Research data and software are widely accepted as an outcome of scientific
work. However, in comparison to text-based publications, there is not yet an
established process to assess and evaluate quality of research data and
research software publications. This paper presents an attempt to fill this
gap. Initiated by the Working Group Open Science of the Helmholtz Association
the Task Group Helmholtz Quality Indicators for Data and Software Publications
currently develops a quality indicator for research data and research software
publications to be used within the Association. This report summarizes the
vision of the group of what all contributes to such an indicator. The proposed
approach relies on generic well-established concepts for quality criteria, such
as the FAIR Principles and the COBIT Maturity Model. It does - on purpose - not
limit itself to technical implementation possibilities to avoid using an
existing metric for a new purpose. The intention of this paper is to share the
current state for further discussion with all stakeholders, particularly with
other groups also working on similar metrics but also with entities that use
the metrics.Comment: 21 pages, 1 figur
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