3,883 research outputs found
Within- and across-breed imputation of high-density genotypes in dairy and beef cattle from medium- and low-density genotypes
peer-reviewedFinancial support of the Irish Department of Agriculture Research Stimulus Fund (RSF-06-0353; RSF-06-0428; 11/SF/311), Science Foundation Ireland (09/IN.1/B2642) and the Irish dairy and beef industry are gratefully acknowledged.The objective of this study was to evaluate, using three different genotype
density panels, the accuracy of imputation from lower- to higher-density
genotypes in dairy and beef cattle. High-density genotypes consisting of
777 962 single-nucleotide polymorphisms (SNP) were available on 3122
animals comprised of 269, 196, 710, 234, 719, 730 and 264 Angus, Belgian
Blue, Charolais, Hereford, Holstein-Friesian, Limousin and Simmental
bulls, respectively. Three different genotype densities were generated:
low density (LD; 6501 autosomal SNPs), medium density (50K; 47 770
autosomal SNPs) and high density (HD; 735 151 autosomal SNPs). Imputation
from lower- to higher-density genotype platforms was undertaken
within and across breeds exploiting population-wide linkage disequilibrium.
The mean allele concordance rate per breed from LD to HD when
undertaken using a single breed or multiple breed reference population
varied from 0.956 to 0.974 and from 0.947 to 0.967, respectively. The
mean allele concordance rate per breed from 50K to HD when undertaken
using a single breed or multiple breed reference population varied from
0.987 to 0.994 and from 0.987 to 0.993, respectively. The accuracy of
imputation was generally greater when the reference population was
solely comprised of the breed to be imputed compared to when the reference
population comprised of multiple breeds, although the impactDepartment of Agriculture, Food and the MarineScience Foundation Irelan
Noise Correlations in a Coulomb Blockaded Quantum Dot
We report measurements of current noise auto- and cross-correlation in a
tunable quantum dot with two or three leads. As the Coulomb blockade is lifted
at finite source-drain bias, the auto-correlation evolves from super-Poissonian
to sub-Poissonian in the two-lead case, and the cross-correlation evolves from
positive to negative in the three-lead case, consistent with transport through
multiple levels. Cross-correlations in the three-lead dot are found to be
proportional to the noise in excess of the Poissonian value in the limit of
weak output tunneling
Competency level in radiotherapy across EU educational programmes: A cross-case study evaluating stakeholders' perceptions
Introduction: The education of Therapeutic Radiographers (TRs) is regulated in some countries but is not
standardised across the EU, leading to differences in competencies between and within member states.
This study aimed to explore stakeholders’ perceptions regarding underdeveloped competencies of TRs
practising on the linear accelerator, identified in a previous study by the same research team.Methods: Interviews with stakeholders from four countries (selected based on the characteristics of their
degrees) were performed as part of this cross-case study. Stakeholders were asked to provide their
perception regarding the least developed competencies identified in a previous study.Results: The 27 stakeholders confirmed that Pharmacology, Quality Assurance (QA), Management and
Leadership, Research (from the previous study) were underdeveloped and identified Image Verification
and Critical Thinking as additional underdeveloped competencies. Suggested causes included: lack of
regulation of required competencies at the national level, lack of training dedicated to radiotherapy (RT)
(taught within generic modules) and lack of time within the degree programme. The ideal academic level
to develop these competencies and whether they are essential varied between country and stakeholder.Conclusion: It is essential to regulate learning outcomes at the national level to ensure a high level of care
is provided to all RT patients and, ideally, standardise it across Europe. Education institutions should
review their curricula to ensure that sufficient time is dedicated to RT and that the essential competencies
are developed. Due to time constraints within some programmes, some competencies must be
developed after graduation.Implications for practice: Lack of regulation of learning outcomes (at European level and national level in
many countries) and lack of RT-specific training lead to underdeveloped competencies that may
compromise patient care.peer-reviewe
Tunable Noise Cross-Correlations in a Double Quantum Dot
We report measurements of the cross-correlation between current noise
fluctuations in two capacitively coupled quantum dots in the Coulomb blockade
regime. The sign of the cross-spectral density is found to be tunable by gate
voltage and source-drain bias. Good agreement is found with a model of
sequential tunneling through the dots in the presence of inter-dot capacitive
coupling.Comment: related papers available at http://marcuslab.harvard.ed
Band-structure topologies of graphene: spin-orbit coupling effects from first principles
The electronic band structure of graphene in the presence of spin-orbit
coupling and transverse electric field is investigated from first principles
using the linearized augmented plane-wave method. The spin-orbit coupling opens
a gap at the -point of the magnitude of 24 eV (0.28 K). This
intrinsic splitting comes 96% from the usually neglected and higher
orbitals. The electric field induces an additional (extrinsic)
Bychkov-Rashba-type splitting of 10 eV (0.11 K) per V/nm, coming from the
- mixing. A 'mini-ripple' configuration with every other atom is
shifted out of the sheet by less than 1% differs little from the intrinsic
case.Comment: 4 pages, 4 figure
Distinct Signatures For Coulomb Blockade and Aharonov-Bohm Interference in Electronic Fabry-Perot Interferometers
Two distinct types of magnetoresistance oscillations are observed in two
electronic Fabry-Perot interferometers of different sizes in the integer
quantum Hall regime. Measuring these oscillations as a function of magnetic
field and gate voltages, we observe three signatures that distinguish the two
types. The oscillations observed in a 2.0 square micron device are understood
to arise from the Coulomb blockade mechanism, and those observed in an 18
square micron device from the Aharonov-Bohm mechanism. This work clarifies,
provides ways to distinguish, and demonstrates control over, these distinct
physical origins of resistance oscillations seen in electronic Fabry-Perot
interferometers.Comment: related papers at http://marcuslab.harvard.ed
Topological Phase Transition and Electrically Tunable Diamagnetism in Silicene
Silicene is a monolayer of silicon atoms forming a honeycomb lattice. The
lattice is actually made of two sublattices with a tiny separation. Silicene is
a topological insulator, which is characterized by a full insulating gap in the
bulk and helical gapless edges. It undergoes a phase transition from a
topological insulator to a band insulator by applying external electric field.
Analyzing the spin Chern number based on the effective Dirac theory, we find
their origin to be a pseudospin meron in the momentum space. The peudospin
degree of freedom arises from the two-sublattice structure. Our analysis makes
clear the mechanism how a phase transition occurs from a topological insulator
to a band insulator under increasing electric field. We propose a method to
determine the critical electric field with the aid of diamagnetism of silicene.
Diamagnetism is tunable by the external electric field, and exhibits a singular
behaviour at the critical electric field. Our result is important also from the
viewpoint of cross correlation between electric field and magnetism. Our
finding will be important for future electro-magnetic correlated devices.Comment: 4 pages,5 figure
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