1,724 research outputs found
Spectral properties of a partially spin-polarized one-dimensional Hubbard/Luttinger superfluid
We calculate the excitation spectra of a spin-polarized Hubbard chain away
from half-filling, using a high-precision momentum-resolved time-dependent
Density Matrix Renormalization Group method. Focusing on the U<0 case, we
present in some detail the single-fermion, pair, density and spin spectra, and
discuss how spin-charge separation is altered for this system. The pair spectra
show a quasi-condensate at a nonzero momentum proportional to the polarization,
as expected for this Fulde-Ferrel-Larkin-Ovchinnikov-like superfluid.Comment: 4 pages, 3 low resolution color fig
Process for the controlled growth of single-crystal films of silicon carbide polytypes on silicon carbide wafers
A method for the controlled growth of single-crystal semiconductor-device-quality films of SiC polytypes on vicinal (0001) SiC wafers with low tilt angles is presented. Both homoepitaxial and heteroepitaxial SiC films can be produced on the same wafer. In particular, 3C-SiC and 6H-SiC films can be produced within selected areas of the same 6H-SiC wafer
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Including Family Carers: Adding Value and Impact to Research
As family carers we are not a homongeneous group but come in all shapes and sizes, and play an invaluable role in society. We have a variety of experiences, and expertise in the needs of the person or people we care for or have cared for as well as our own experiences of being carers. Across the diverse group of carers and caring situations, we each have our own individual voice which may differ from that of the person we care for.
Yet, in research studies our voices are sometimes excluded or only sought when the cared for person is unable to give their own views. The focus on services or the cared for person can sometimes ignore the experience and expertise carers bring to an issue. Often the symbiotic nature of the caring relationship is not recognised; so when the focus is on interventions for the cared for person the resulting impact on their carers is overlooked. There is no doubt that more research is needed on the role, needs and support for carers. But ther is also no doubt that the voice of carers needs to be captured across all health and social care studies even when the focus is on the cared for person.
This report, from a workshop organised by the Independent Advisory Group on Carers and the NIHR School for Social Care Research, highlights the pivotal role carers play in the effectiveness of future health and social care-related research. Carers can be valuable partners, providing unique inputs into all stages of research design, from forming the research question to the methodology, analysis and in sharing the findings.
Our voice as carers needs to become an integral part of all health or social care-related research studies. There are actions that research funders, research teams, the health and social care sectors, and carers can take to make this happen. This report highlights some of these but it is important that actions follow. The first step is to recognise carers as a distinct, diverse and valuable group in research.
We welcome positive steps being taken to achieve the priorities set out in this report
Estimating the degree of saturation in mutant screens
Large-scale screens for loss-of-function mutants have played a significant role in recent advances in developmental biology and other fields. In such mutant screens, it is desirable to estimate the degree of saturation of the screen (i.e., what fraction of the possible target genes has been identified). We applied Bayesian and maximum-likelihood methods for estimating the number of loci remaining undetected in large-scale screens and produced credibility intervals to assess the uncertainty of these estimates. Since different loci may mutate to alleles with detectable phenotypes at different rates, we also incorporated variation in the degree of mutability among genes, using either gamma-distributed mutation rates or multiple discrete mutation rate classes. We examined eight published data sets from large-scale mutant screens and found that credibility intervals are much broader than implied by previous assumptions about the degree of saturation of screens. The likelihood methods presented here are a significantly better fit to data from published experiments than estimates based on the Poisson distribution, which implicitly assumes a single mutation rate for all loci. The results are reasonably robust to different models of variation in the mutability of genes. We tested our methods against mutant allele data from a region of the Drosophila melanogaster genome for which there is an independent genomics-based estimate of the number of undetected loci and found that the number of such loci falls within the predicted credibility interval for our models. The methods we have developed may also be useful for estimating the degree of saturation in other types of genetic screens in addition to classical screens for simple loss-of-function mutants, including genetic modifier screens and screens for protein-protein interactions using the yeast two-hybrid method
An overview of recent advances in intrusion detection
The intrusion detection system is one of the security defense tools for computer networks. In recent years this research has lacked in direction and focus. In this paper we present a survey on the recent progression of multiagent intrusion detection systems. We survey the existing types, techniques and architectures of Intrusion Detection Systems in the literature. Finally we outline the present research challenges and issue
Mapping optical path length and image enhancement using quantitative orientation-independent differential interference contrast microscopy
Author Posting. © Society of Photo Optical Instrumentation Engineers, 2017. This article is posted here by permission of Society of Photo Optical Instrumentation Engineers for personal use, not for redistribution. The definitive version was published in Journal of Biomedical Optics 22 (2017): 016006, doi:10.1117/1.JBO.22.1.016006.We describe the principles of using orientation-independent differential interference contrast (OI-DIC) microscopy for mapping optical path length (OPL). Computation of the scalar two-dimensional OPL map is based on an experimentally received map of the OPL gradient vector field. Two methods of contrast enhancement for the OPL image, which reveal hardly visible structures and organelles, are presented. The results obtained can be used for reconstruction of a volume image. We have confirmed that a standard research grade light microscope equipped with the OI-DIC and 100×/1.3 NA objective lens, which was not specially selected for minimum wavefront and polarization aberrations, provides OPL noise level of ∼0.5  nm and lateral resolution if ∼300  nm at a wavelength of 546 nm. The new technology is the next step in the development of the DIC microscopy. It can replace standard DIC prisms on existing commercial microscope systems without modification. This will allow biological researchers that already have microscopy setups to expand the performance of their systems.This
publication was made possible by Grant No. R01-GM101701
from the National Institute of General Medical Sciences,
National Institutes of Health
Malicious code detection architecture inspired by human immune system
Malicious code is a threat to computer systems globally. In this paper, we outline the evolution of malicious code attacks. The threat is evolving, leaving challenges for attackers to improve attack techniques and for researchers and security specialists to improve detection accuracy. We present a novel architecture for an effective defense against malicious code attack, inspired by the human immune system. We introduce two phases of program execution: Adolescent and Mature Phase. The first phase uses a malware profile matching mechanism, whereas the second phase uses a program profile matching mechanism. Both mechanisms are analogous to the innate immune syste
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