Characterization and suppression techniques for degree of radiation damping in inversion recovery measurements

Radiation damping (RD) has been shown to affect T1 measurement in inversion recovery experiments. In this work, we demonstrate that the extent of RD depends upon the T1 of the sample. RD difference spectroscopy (RADDSY) is used to characterize the severity of RD, while gradient inversion recovery (GIR) is used for RD suppression in T1 measurements. At 9.4 T, for the radiation damping characteristic time (Trd) of 50 ms, these investigations show non-negligible RD effects for T1 values greater than Trd, with severe distortions for T1 longer than about 150 ms, showing reasonable agreement with the predicted Trd. We also report a discrepancy between published expressions for the characteristic RD time

High MRSA Carriage Rate among Nursing Microbiology Students

Staphylococcus aureus is a common cause of disease, particularly in colonized persons. Although methicillin-resistant S. aureus (MRSA) infections have become increasingly reported, populationbased studies of students preparing for the health professions having S. aureus and MRSA colonization are lacking. We have found that students in microbiology classes having more contact with individuals in a healthcare setting are more likely to carry MRSA in their nares and axilla. The classes who had the highest rate of MRSA carriage during the school year, 2013-2014, were those with nursing students, who had a greater exposure to clinical settings and nursing homes. The class which had the highest rate of S. aureus carriage, had nearly 50% of the infected students had been involved a clinical setting. Since the majority of the students in the nursing and biology courses are looking to pursue a career in medicine, this sampling was very beneficial to inform them and others if they were a carrier of S. aureus and MRSA and the preventative measures to reduce the risk of infection

On well-rounded sublattices of the hexagonal lattice

We produce an explicit parameterization of well-rounded sublattices of the hexagonal lattice in the plane, splitting them into similarity classes. We use this parameterization to study the number, the greatest minimal norm, and the highest signal-to-noise ratio of well-rounded sublattices of the hexagonal lattice of a fixed index. This investigation parallels earlier work by Bernstein, Sloane, and Wright where similar questions were addressed on the space of all sublattices of the hexagonal lattice. Our restriction is motivated by the importance of well-rounded lattices for discrete optimization problems. Finally, we also discuss the existence of a natural combinatorial structure on the set of similarity classes of well-rounded sublattices of the hexagonal lattice, induced by the action of a certain matrix monoid.Comment: 21 pages (minor correction to the proof of Lemma 2.1); to appear in Discrete Mathematic

Recommendations for Incorporating Postsecondary and Workforce Data into Statewide Longitudinal Data Systems

Outlines the need for data systems to assess educational transitions, completions, and labor market outcomes of adult students and workers in postsecondary, adult education, and skill development programs in order to strengthen policies and programs

Classification of Stellar Spectra with LLE

We investigate the use of dimensionality reduction techniques for the classification of stellar spectra selected from the SDSS. Using local linear embedding (LLE), a technique that preserves the local (and possibly non-linear) structure within high dimensional data sets, we show that the majority of stellar spectra can be represented as a one dimensional sequence within a three dimensional space. The position along this sequence is highly correlated with spectral temperature. Deviations from this "stellar locus" are indicative of spectra with strong emission lines (including misclassified galaxies) or broad absorption lines (e.g. Carbon stars). Based on this analysis, we propose a hierarchical classification scheme using LLE that progressively identifies and classifies stellar spectra in a manner that requires no feature extraction and that can reproduce the classic MK classifications to an accuracy of one type.Comment: 15 pages, 13 figures; accepted for publication in The Astronomical Journa

Cal Poly Table Top

Since many tables currently used at Cal Poly are not ideal for active design situations, we have designed, built and tested to be used in design classrooms with an emphasis on using the tables to quickly prototype ideas. This table is a standing height table in a trapezoidal shape which can comfortably seat four people. The modular design of the table allows multiple tables to be use to create different shapes so that the tables can be used in multiple ways

Measurement of Three Transport Coefficients and the Thermodynamic Factor in Block Copolymer Electrolytes with Different Morphologies.

The design and engineering of composite materials is one strategy to satisfy the materials needs of systems with multiple orthogonal property requirements. In the case of rechargeable batteries with lithium metal anodes, the system requires a separator with fast lithium ion transport and good mechanical strength. In this work, we focus on the system polystyrene-block-poly(ethylene oxide) (SEO) with bis(trifluoromethane)sulfonimide lithium salt (LiTFSI). Ion transport occurs in the salt-containing poly(ethylene oxide)-rich domains. Mechanical rigidity arises due to the glassy nature of polystyrene (PS). If we assume that the salt does not interact with the PS-rich domains, we can describe ion transport in the electrolyte by three transport parameters (ionic conductivity, κ, salt diffusion coefficient, D, and cation transference number, t+0) and a thermodynamic factor, Tf. By systematically varying the volume fraction of the conducting phase, ϕc between 0.29 and 1.0, and chain length, N between 80 and 8000, we elucidate the role of morphology on ion transport. We find that κ is the strongest function of morphology, varying by three full orders of magnitude, while D is a weaker function of morphology. To calculate t+0 and Tf, we measure the current fraction, ρ+, and the open circuit potential, U, of concentration cells. We find that ρ+ and U follow universal trends as a function of salt concentration, regardless of chain length, morphology, or ϕc, allowing us to calculate t+0 for any SEO/LiTFSI or PEO/LiTFSI mixture when κ and D are known. The framework developed in this paper enables predicting the performance of any block copolymer electrolyte in a rechargeable battery