A Comment on the Implementation of the Ziggurat Method

We show that the short period of the uniform random number generator in the published implementation of Marsaglia and Tsang's Ziggurat method for generating random deviates can lead to poor distributions. Changing the uniform random number generator used in its implementation fixes this issue.

Tracking Lumbar Vertebrae in Digital Videofluoroscopic Video Automatically

Low back pain becomes one of the significant problem in the industrialized world. Efficient and effective spinal motion analysis is required to understand low back pain and to aid the diagnosis. Videofluoroscopy provides a cost effective way for such analysis. However, common approaches are tedious and time consuming due to the low quality of the images. Physicians have to extract the vertebrae manually in most cases and thus continuous motion analysis is hardly achieved. In this paper, we propose a system which can perform automatic vertebrae segmentation and tracking. Operators need to define exact location of landmarks in the first frame only. The proposed system will continuously learn the texture pattern along the edge and the dynamics of the vertebrae in the remaining frames. The system can estimate the location of the vertebrae based on the learnt texture and dynamics throughout the sequence. Experimental results show that the proposed system can segment vertebrae from videofluoroscopic images automatically and accurately. © Springer-Verlag 2004.postprintThe International Workshop on Medical Imaging and Augmented Reality (MIAR 2004), Beijing, China, 19-20 August 2004. In Lecture Notes in Computer Science, 2004, v. 3150, p. 154-16

Bring Your Own Mobile Device (BYOD) to the Hospital: Layered Boundary Barriers and Divergent Boundary Management Strategies

This study examined how one US hospital implemented a mobile communication app to improve workplace communication. The hospital did not provide the technology, instead they asked their workers to use their own personal mobiles at work, through a permissive bring your own device to work (BYOD) policy. Using boundary theory, we conducted a constant-comparative analysis to examine the layers of boundary management issues. At the organizational level, the key issues were policy legacy, communicating the policy, control, dead zones, and mobile costs. At the group level, different hospital units created their own formal and informal policies. At the individual level, themes included personal mobile device use, job role expectations, and decision-making autonomy. The discussion presents examples of how healthcare workers enacted segregator and integrator boundaries. Our findings explain why it is not easy to tell hospital employees, “Go ahead and use your mobiles for patient care,” and have them embrace this practice

How good are Global Newton methods? Part 2

Newton's method applied to certain problems with a discontinuous derivative operator is shown to be effective. A global Newton method in this setting is exhibited and its computational complexity is estimated. As an application a method is proposed to solve problems of linear inequalities (linear programming, phase 1). Using an example of the Klee-Minty type due to Blair, it was found that the simplex method (used in super-lindo) required over 2,000 iterations, while the method above required an average of 8 iterations (Newton steps) over 15 random starting values.Naval Surface Weapons Center, Dahlgren, VAhttp://archive.org/details/howgoodareglobal00goldO&MN Direct FundingApproved for public release; distribution is unlimited

Doping-tunable thermal emission from plasmon polaritons in semiconductor epsilon-near-zero thin films

We utilize the unique dispersion properties of leaky plasmon polaritons in epsilon-near-zero (ENZ) thin films to demonstrate thermal radiation control. Owing to its highly flat dispersion above the light line, a thermally excited leaky wave at the ENZ frequency out-couples into free space without any scattering structures, resulting in a narrowband, wide-angle, p-polarized thermal emission spectrum. We demonstrate this idea by measuring angle-and polarization-resolved thermal emission spectra from a single layer of unpatterned, doped semiconductors with deep-subwavelength film thickness (d/lambda(0) similar to 6 x 10(-3), where d is the film thickness and lambda(0) is the free space wavelength). We show that this semiconductor ENZ film effectively works as a leaky wave thermal radiation antenna, which generates far-field radiation from a thermally excited mode. The use of semiconductors makes the radiation frequency highly tunable by controlling doping densities and also facilitates device integration with other components. Therefore, this leaky plasmon polariton emission from semiconductor ENZ films provides an avenue for on-chip control of thermal radiation. (C) 2014 AIP Publishing LLCopen0

A single H/ACA small nucleolar RNA mediates tumor suppression downstream of oncogenic RAS.

Small nucleolar RNAs (snoRNAs) are a diverse group of non-coding RNAs that direct chemical modifications at specific residues on other RNA molecules, primarily on ribosomal RNA (rRNA). SnoRNAs are altered in several cancers; however, their role in cell homeostasis as well as in cellular transformation remains poorly explored. Here, we show that specific subsets of snoRNAs are differentially regulated during the earliest cellular response to oncogenic RASG12V expression. We describe a novel function for one H/ACA snoRNA, SNORA24, which guides two pseudouridine modifications within the small ribosomal subunit, in RAS-induced senescence in vivo. We find that in mouse models, loss of Snora24 cooperates with RASG12V to promote the development of liver cancer that closely resembles human steatohepatitic hepatocellular carcinoma (HCC). From a clinical perspective, we further show that human HCCs with low SNORA24 expression display increased lipid content and are associated with poor patient survival. We next asked whether ribosomes lacking SNORA24-guided pseudouridine modifications on 18S rRNA have alterations in their biophysical properties. Single-molecule Fluorescence Resonance Energy Transfer (FRET) analyses revealed that these ribosomes exhibit perturbations in aminoacyl-transfer RNA (aa-tRNA) selection and altered pre-translocation ribosome complex dynamics. Furthermore, we find that HCC cells lacking SNORA24-guided pseudouridine modifications have increased translational miscoding and stop codon readthrough frequencies. These findings highlight a role for specific snoRNAs in safeguarding against oncogenic insult and demonstrate a functional link between H/ACA snoRNAs regulated by RAS and the biophysical properties of ribosomes in cancer