975 research outputs found
Ultra-compact radio sources: angular-size/redshift data
A compilation of angular-size/redshift data for ultra-compact radio sources is presented, which data derive from a 2.29 GHz VLBI survey undertaken by Preston et al. The sample has formed the basis of a number of investigations, which attempt to determine cosmological parameters from the angular-size/redshift diagram. Full details of the sample are not in the public domain, which omission is rectified here
Design and evaluation of a genomics variant analysis pipeline using GATK Spark tools
Scalable and efficient processing of genome sequence data, i.e. for variant
discovery, is key to the mainstream adoption of High Throughput technology for
disease prevention and for clinical use. Achieving scalability, however,
requires a significant effort to enable the parallel execution of the analysis
tools that make up the pipelines. This is facilitated by the new Spark versions
of the well-known GATK toolkit, which offer a black-box approach by
transparently exploiting the underlying Map Reduce architecture. In this paper
we report on our experience implementing a standard variant discovery pipeline
using GATK 4.0 with Docker-based deployment over a cluster. We provide a
preliminary performance analysis, comparing the processing times and cost to
those of the new Microsoft Genomics Services
Advanced deconvolution techniques and medical radiography
Medical radiography is a process by which the internal structures of the human body are imaged using a source of x-rays. The images formed are essentially shadowgrams whose size and intensity is dependent on the geom¬etry of the imaging system and the degree to which the structures attenuate x-ray radiation. The images are blurred because the x-ray source has a finite size, and noisy because the x-ray exposure must be kept as low as possible for the safety of the patient but which also limits the number of photons avail¬able for image formation. In such noisy environments traditional methods of Fourier deconvolution have limited appeal. In this research we apply maximum entropy methods (MEM) to some radiological images. We justify the choice of MEM over other deconvolution schemes by processing a selection of artificial images in which the blur and noise mimic the real situation but whose levels are known a priori. A hybrid MEM scheme is developed to address the shortcomings of so-called historic MEM in these situations. We initially consider images from situations in which the model point- spread function is assumed to be three-dimensionally spatially invariant, and which approximates the real situation reasonably well. One technique lends itself well to this investigation: magnification mammography. MEM is offered as a way of breaking some of the conflicting performance requirements of this technique and we explore several new system possibilities with a working MEM system in place. A more complicated blurring function is encountered in linear tomography, which uses opposing movements of the image receptor and x-ray source to generate planar images through an object. Features outside a particular focal plane are smeared to such an extent that detail within the focal plane can be very difficult to detect. With appropriate modification of our MEM technique, processed images show a significant reduction to the blurring outside the focal plane
Surveying the Field: State-Level Findings From the 2008 Parole Practices Survey
Surveys the use of evidence-based parole supervision practices based on a risk reduction approach across states; obstacles to their implementation; and approaches to enhancing parolee motivation. Profiles efforts to improve practices in three states
Policing 2016 To Deliver Safety, Police Need Legitimacy and Accountability
Much of the national debate on policing in 2015 has rested on a false premise—that community demands for greater police accountability come at the expense of effectively addressing crime. In fact, police need accountability and legitimacy in the communities they serve if they are to deliver safety. While policing is a local governmental function, federal policymakers have an important role to play in helping policing practice reflect this truth. The next president will have a wide range of funding, agenda setting, and enforcement tools that can elevate and spread the best in policing and compel reform where necessary
Mammographic image restoration using maximum entropy deconvolution
An image restoration approach based on a Bayesian maximum entropy method
(MEM) has been applied to a radiological image deconvolution problem, that of
reduction of geometric blurring in magnification mammography. The aim of the
work is to demonstrate an improvement in image spatial resolution in realistic
noisy radiological images with no associated penalty in terms of reduction in
the signal-to-noise ratio perceived by the observer. Images of the TORMAM
mammographic image quality phantom were recorded using the standard
magnification settings of 1.8 magnification/fine focus and also at 1.8
magnification/broad focus and 3.0 magnification/fine focus; the latter two
arrangements would normally give rise to unacceptable geometric blurring.
Measured point-spread functions were used in conjunction with the MEM image
processing to de-blur these images. The results are presented as comparative
images of phantom test features and as observer scores for the raw and
processed images. Visualization of high resolution features and the total image
scores for the test phantom were improved by the application of the MEM
processing. It is argued that this successful demonstration of image
de-blurring in noisy radiological images offers the possibility of weakening
the link between focal spot size and geometric blurring in radiology, thus
opening up new approaches to system optimization.Comment: 18 pages, 10 figure
FASTTRACK RECOMMENDER SYSTEM
Network operators are overloaded with numerous recommendations coming from vendors, some of which come from automated recommender systems. Such automated recommendations may or may not apply to a customer’s specific environment, often lack an assessment of priority within the context of the other recommendations, and may or may not apply to an individual customer’s scenario. To address these challenges, techniques are presented herein that provide a novel approach to generating and ranking recommendations coming from a dynamic recommender system where rankings are based on enriched context from, for example, live data on real networks, activities performed by real customers, etc. Such techniques enhance the operational features of existing networks by recommending popular items to new customers, identifying critical items that can be proactively addressed in order to provide additional services, and reducing Technical Assistance Center (TAC) cases when patches exist for common issues
Mistrust and Ambivalence between Residents and the Police: Evidence from Four Chicago Neighborhoods
This brief examines the fractured relationship between residents in high-crime Chicago neighborhoods and the police that serve those communities. Based on surveys of people living in and police officers serving in four Chicago police districts on the city's south and west sides collected as part of the evaluation of the Chicago Violence Reduction Strategy, these data demonstrate ambivalence between the police and residents. Community members do not generally perceive the police as acting in a procedurally fair manner and do not support their work; this perception is particularly high among people with recent arrest histories in co-offending networks. Police officers do not believe the community trusts them, and officers express little confidence or trust in those living in the districts they police. However, residents are generally willing to cooperate with the police on crime control efforts
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Parolees' physical closeness to health service providers: a study of California parolees.
We studied a sample of parolees and health service providers in the state of California in 2005-2006 to examine the relative physical closeness to health providers (and the potential demand of these providers) of parolees based on their demographic and prior offending characteristics. Although African-American and Latino parolees have more health providers nearby, these providers have considerably more potential demand. The health providers near long-term prisoners and sex offenders have more potential demand. The results suggest inequity in access to services, as minority parolees and those with greater needs may live near more impacted providers. The results also suggest some differences in access based on rural, suburban, or urban location
Educational Costs of Gun Violence: Implications for Washington, DC
Research indicates that gun violence and violent crime can negatively affect educational outcomes including test scores, graduation rates, and academic engagement. In this brief, we summarize research on this topic, situate this evidence in the context of the geography of gun violence and educational outcomes in DC, and describe implications for DC communities
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