51,733 research outputs found
Human ethics guidelines for schools
The article depicts the development, the process and the composition human ethics guidelines for schools in New Zealand. It states that the guidelines must be provided at schools for guiding school-based student research that requires human beings as participants in the research. The guidelines is also necessary in helping student and teacher researchers to plan their investigations with foresight and to alert school management to their responsibilities and possible issues and risks
Assessment of available anatomical characters for linking living mammals to fossil taxa in phylogenetic analyses
ORCID: 0000-0003-4919-8655© 2016 The Authors.
Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. The file attached is the published version of the article
Supersymmetric analysis for the Dirac equation with spin-symmetric and pseudo-spin-symmetric interactions
A supersymmetric analysis is presented for the d-dimensional Dirac equation
with central potentials under spin-symmetric
(S(r) = V(r)) and pseudo-spin-symmetric (S(r) = - V(r)) regimes. We construct
the explicit shift operators that are required to factorize the Dirac
Hamiltonian with the Kratzer potential. Exact solutions are provided for both
the Coulomb and Kratzer potentials.Comment: 12 page
Extended Supersymmetries and the Dirac Operator
We consider supersymmetric quantum mechanical systems in arbitrary dimensions
on curved spaces with nontrivial gauge fields. The square of the Dirac operator
serves as Hamiltonian. We derive a relation between the number of supercharges
that exist and restrictions on the geometry of the underlying spaces as well as
the admissible gauge field configurations. From the superalgebra with two or
more real supercharges we infer the existence of integrability conditions and
obtain a corresponding superpotential. This potential can be used to deform the
supercharges and to determine zero modes of the Dirac operator. The general
results are applied to the Kahler spaces CP^n.Comment: 22 pages, no figure
Semiquantum Chaos and the Large N Expansion
We consider the dynamical system consisting of a quantum degree of freedom
interacting with quantum oscillators described by the Lagrangian \bq L
= {1\over 2}\dot{A}^2 + \sum_{i=1}^{N} \left\{{1\over 2}\dot{x}_i^2 - {1\over
2}( m^2 + e^2 A^2)x_i^2 \right\}. \eq In the limit , with
fixed, the quantum fluctuations in are of order . In this
limit, the oscillators behave as harmonic oscillators with a time dependent
mass determined by the solution of a semiclassical equation for the expectation
value \VEV{A(t)}. This system can be described, when \VEV{x(t)}= 0, by a
classical Hamiltonian for the variables G(t) = \VEV{x^2(t)}, ,
A_c(t) = \VEV{A(t)}, and . The dynamics of this latter system
turns out to be chaotic. We propose to study the nature of this large- limit
by considering both the exact quantum system as well as by studying an
expansion in powers of for the equations of motion using the closed time
path formalism of quantum dynamics.Comment: 30 pages, uuencoded LaTeX file (figures included
On the nature of fermion-monopole supersymmetry
It is shown that the generator of the nonstandard fermion-monopole
supersymmetry uncovered by De Jonghe, Macfarlane, Peeters and van Holten, and
the generator of its standard N=1/2 supersymmetry have to be supplemented by
their product operator to be treated as independent supercharge. As a result,
the fermion-monopole system possesses the nonlinear N=3/2 supersymmetry having
the nature of the 3D spin-1/2 free particle's supersymmetry generated by the
supercharges represented in a scalar form. Analyzing the supercharges'
structure, we trace how under reduction of the fermion-monopole system to the
spherical geometry the nonlinear N=3/2 superalgebra comprising the Hamiltonian
and the total angular momentum as even generators is transformed into the
standard linear N=1 superalgebra with the Hamiltonian to be the unique even
generator.Comment: 8 pages, minor extension of concluding comment
Real-Time Dynamics with Fermions on a Lattice
The 1+1 dimensional abelian Higgs model with fermions is a toy model for the
theory of electroweak baryogenesis. We study the dynamics of the model with
axially coupled fermions in real-time. The model is defined on a spacetime
lattice to preserve gauge invariance and to obtain numerical stability in a
simple way. We take into account the phenomenon of lattice fermion doubling.
The dynamics is approximated by treating the inhomogeneous Bose fields
classically, which is justified in a large N_f approximation. The back reaction
on the Bose fields due to fermion field fluctuations is calculated using a mode
function expansion. We discuss and present numerical results for the response
of fermions to sphaleron transitions, the renormalizability of the effective
equations of motion and non-perturbative dynamics in the framework of
non-equilibrium quantum field theory. The long-time behaviour of the system is
discussed and we speculate about applications to finite density calculations.Comment: 34 pages + 20 eps figures, improved presentation, discussion of the
figures and figure captions expanded, references added; to appear in
Nucl.Phys.
Resumming the large-N approximation for time evolving quantum systems
In this paper we discuss two methods of resumming the leading and next to
leading order in 1/N diagrams for the quartic O(N) model. These two approaches
have the property that they preserve both boundedness and positivity for
expectation values of operators in our numerical simulations. These
approximations can be understood either in terms of a truncation to the
infinitely coupled Schwinger-Dyson hierarchy of equations, or by choosing a
particular two-particle irreducible vacuum energy graph in the effective action
of the Cornwall-Jackiw-Tomboulis formalism. We confine our discussion to the
case of quantum mechanics where the Lagrangian is . The
key to these approximations is to treat both the propagator and the
propagator on similar footing which leads to a theory whose graphs have the
same topology as QED with the propagator playing the role of the photon.
The bare vertex approximation is obtained by replacing the exact vertex
function by the bare one in the exact Schwinger-Dyson equations for the one and
two point functions. The second approximation, which we call the dynamic Debye
screening approximation, makes the further approximation of replacing the exact
propagator by its value at leading order in the 1/N expansion. These two
approximations are compared with exact numerical simulations for the quantum
roll problem. The bare vertex approximation captures the physics at large and
modest better than the dynamic Debye screening approximation.Comment: 30 pages, 12 figures. The color version of a few figures are
separately liste
Phylogenomic study of Burkholderia glathei-like organisms, proposal of 13 novel Burkholderia species and emended descriptions of Burkholderia sordidicola, Burkholderia zhejiangensis, and Burkholderia grimmiae
Partial gyrB gene sequence analysis of 17 isolates from human and environmental sources revealed 13 clusters of strains and identified them as Burkholderia glathei Glade (BGC) bacteria. The taxonomic status of these clusters was examined by whole-genome sequence analysis, determination of the G+C content, whole-cell fatty acid analysis and biochemical characterization. The whole-genome sequence-based phylogeny was assessed using the Genome Blast Distance Phylogeny (GBDP) method and an extended multilocus sequence analysis (MLSA) approach. The results demonstrated that these 17 BGC isolates represented 13 novel Burkholderia species that could be distinguished by both genotypic and phenotypic characteristics. BGC strains exhibited a broad metabolic versatility and developed beneficial, symbiotic, and pathogenic interactions with different hosts. Our data also confirmed that there is no phylogenetic subdivision in the genus Burkholderia that distinguishes beneficial from pathogenic strains. We therefore propose to formally classify the 13 novel BGC Burkholderia species as Burkholderia arvi sp. nov. (type strain LMG 29317(T) = CCUG 68412(T)), Burkholderia hypogeia sp. nov. (type strain LMG 29322(T) = CCUG 68407(T)), Burkholderia ptereochthonis sp. nov. (type strain LMG 29326(T) = CCUG 68403(T)), Burkholderia glebae sp. nov. (type strain LMG 29325(T) = CCUG 68404(T)), Burkholderia pedi sp. nov. (type strain LMG 29323(T) = CCUG 68406(T)), Burkholderia arationis sp. nov. (type strain LMG 29324(T) = CCUG 68405(T)), Burkholderia fortuita sp. nov. (type strain LMG 29320(T) = CCUG 68409(T)), Burkholderia temeraria sp. nov. (type strain LMG 29319(T) = CCUG 68410(T)), Burkholderia calidae sp. nov. (type strain LMG 29321(T) = CCUG 68408(T)), Burkholderia concitans sp. nov. (type strain LMG 29315(T) = CCUG 68414(T)), Burkholderia turbans sp. nov. (type strain LMG 29316(T) = CCUG 68413(T)), Burkholderia catudaia sp. nov. (type strain LMG 29318(T) = CCUG 68411(T)) and Burkholderia peredens sp. nov. (type strain LMG 29314(T) = CCUG 68415(T)). Furthermore, we present emended descriptions of the species Burkholderia sordidicola, Burkholderia zhejlangensis and Burkholderia grimmiae. The GenBank/EMBUDDBJ accession numbers for the 16S rRNA and gyrB gene sequences determined in this study are LT158612-LT158624 and LT158625-LT1158641, respectively
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