Crystallization of the glassy phase of grain boundaries in silicon nitride

Three types of hot-pressed silicon nitride specimens (containing 5wt% Y2O3 and 2wt% Al2O3 additives) which were subjected to different temperature heat treatments were studied by X-ray diffraction, X-ray microanalysis and high resolution electron microscopy. The results indicated that there were phase changes in the grain boundaries after heat treatment and the glassy phase at the grain boundaries was crystallized by heat treatment

Entanglement between static and flying qubits in a semiconducting carbon nanotube

Entanglement can be generated by two electrons in a spin-zero state on a semiconducting single-walled carbon nanotube. The two electrons, one weakly bound in a shallow well in the conduction band, and the other injected into the conduction band, are coupled by the Coulomb interaction. Both transmission and entanglement are dependent on the well characteristics, which can be controlled by a local gate, and on the kinetic energy of the injected electron. Regimes with different degrees of electron correlation exhibit full or partial entanglement. In the latter case, the maximum entanglement can be estimated as a function of width and separation of a pair of singlet-triplet resonances.Comment: 17 pages and 12 figures, accepted to J. Phys. Cond. Ma

Spin detection at elevated temperatures using a driven double quantum dot

We consider a double quantum dot in the Pauli blockade regime interacting with a nearby single spin. We show that under microwave irradiation the average electron occupations of the dots exhibit resonances that are sensitive to the state of the nearby spin. The system thus acts as a spin meter for the nearby spin. We investigate the conditions for a non-demolition read-out of the spin and find that the meter works at temperatures comparable to the dot charging energy and sensitivity is mainly limited by the intradot spin relaxation.Comment: 8 pages, 6 figure

Selected Consumers\u27 Evaluations of Genetically Modified Food Labels

Genetically modified (GM) organisms are commonplace in modern agricultural practice. However, polls and surveys have indicated a lack of consumer acceptance of GM ingredients and a desire to see such products identified through the use of labels. In this study, three focus groups composed of consumers in two northwest Arkansas counties evaluated and discussed four genetically modified food labels developed through the use of the Elaboration Likelihood Model, a persuasive communication theory. Findings revealed that participants want labels on food containing GM ingredients. Participants agreed on two features that a GM food label should have: contact information and an identifying symbol. They felt that this label should appear on the front of the package or near the nutrition information. Participants also wanted more consumer education about GM foods and indicated that any label adopted in the future should identify them as such. Further qualitative and quantitative research on consumer preferences regarding GM food labels and the design of such labels is needed

The Death Penalty on the Streets: What the Eighth Amendment Can Teach About Regulating Police Use of Force

This Article offers punishment as another lens through which to view police force. The Supreme Court has consistently rejected arguments that the Eighth Amendment is the appropriate vehicle for dealing with excessive police force claims.5 However, reconceptualizing the use of deadly force by police officers as punishment provides a new understanding of the gravity of deadly police force and adds necessary substance to the reasonableness analysis. When police force is likened to punishment, the use of fatal force by police officers can be considered the administration of the death penalty on the streets, absent the procedural protections and focus on human dignity given in the criminal justice system through the Eighth Amendment.6 When considered in the context of punishment, the reasonableness analysis can be transformed to incorporate the value of human dignity and focus on protections against fatal police force that ought to be in place to protect the lives of all individuals

Entanglement between static and flying qubits in quantum wires

A weakly bound electron in a semiconductor quantum wire is shown to become entangled with an itinerant electron via the coulomb interaction. The degree of entanglement and its variation with energy of the injected electron, may be tuned by choice of spin and initial momentum. Full entanglement is achieved close to energies where there are spin-dependent resonances. Possible realisations of related device structures are discussed

Evidence of spontaneous spin polarized transport in magnetic nanowires

The exploitation of the spin in charge-based systems is opening revolutionary opportunities for device architecture. Surprisingly, room temperature electrical transport through magnetic nanowires is still an unresolved issue. Here, we show that ferromagnetic (Co) suspended atom chains spontaneously display an electron transport of half a conductance quantum, as expected for a fully polarized conduction channel. Similar behavior has been observed for Pd (a quasi-magnetic 4d metal) and Pt (a non-magnetic 5d metal). These results suggest that the nanowire low dimensionality reinforces or induces magnetic behavior, lifting off spin degeneracy even at room temperature and zero external magnetic field.Comment: 4 pages, 3 eps fig

HAC stability in murine cells is influenced by nuclear localization and chromatin organization

<p>Abstract</p> <p>Background</p> <p>Human artificial chromosomes (HAC) are small functional extrachromosomal elements, which segregate correctly during each cell division. In human cells, they are mitotically stable, however when the HAC are transferred to murine cells they show an increased and variable rate of loss. In some cell lines the HAC are lost over a short period of time, while in others the HAC become stable without acquiring murine DNA.</p> <p>Results</p> <p>In this study, we linked the loss rate to the position of the HAC in the murine cell nucleus with respect to the chromocenters. HAC that associated preferentially with the chromocenter displayed a lower loss rate compared to the HAC that are less frequently associated. The chromocenter acts as a hub for the deposition of heterochromatic markers, controlling centromeric and pericentromeric DNA replication timing and chromosome segregation. The HAC which localized more frequently outside the chromocenters bound variable amounts of histone H3 tri-methylated at lysine 9, and the high level of intraclonal variability was associated with an increase in HAC segregation errors and delayed DNA replication timing.</p> <p>Conclusion</p> <p>This is a novel result indicating that HAC segregation is closely linked to the position in the murine nucleus and gives important insight for HAC gene expression studies in murine cells and establishing murine models of human genetic disease.</p

HAC stability in murine cells is influenced by nuclear localization and chromatin organization

<p>Abstract</p> <p>Background</p> <p>Human artificial chromosomes (HAC) are small functional extrachromosomal elements, which segregate correctly during each cell division. In human cells, they are mitotically stable, however when the HAC are transferred to murine cells they show an increased and variable rate of loss. In some cell lines the HAC are lost over a short period of time, while in others the HAC become stable without acquiring murine DNA.</p> <p>Results</p> <p>In this study, we linked the loss rate to the position of the HAC in the murine cell nucleus with respect to the chromocenters. HAC that associated preferentially with the chromocenter displayed a lower loss rate compared to the HAC that are less frequently associated. The chromocenter acts as a hub for the deposition of heterochromatic markers, controlling centromeric and pericentromeric DNA replication timing and chromosome segregation. The HAC which localized more frequently outside the chromocenters bound variable amounts of histone H3 tri-methylated at lysine 9, and the high level of intraclonal variability was associated with an increase in HAC segregation errors and delayed DNA replication timing.</p> <p>Conclusion</p> <p>This is a novel result indicating that HAC segregation is closely linked to the position in the murine nucleus and gives important insight for HAC gene expression studies in murine cells and establishing murine models of human genetic disease.</p