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 $K(K')$-point of the magnitude of 24 $\mu$eV (0.28 K). This intrinsic splitting comes 96% from the usually neglected $d$ and higher orbitals. The electric field induces an additional (extrinsic) Bychkov-Rashba-type splitting of 10 $\mu$eV (0.11 K) per V/nm, coming from the $\sigma$-$\pi$ 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