A suite of methods for representing activity space in a healthcare accessibility study

BACKGROUND: "Activity space" has been used to examine how people's habitual movements interact with their environment, and can be used to examine accessibility to healthcare opportunities. Traditionally, the standard deviational ellipse (SDE), a Euclidean measure, has been used to represent activity space. We describe the construction and application of the SDE at one and two standard deviations, and three additional network-based measures of activity space using common tools in GIS: the road network buffer (RNB), the 30-minute standard travel time polygon (STT), and the relative travel time polygon (RTT). We compare the theoretical and methodological assumptions of each measure, and evaluate the measures by examining access to primary care services, using data from western North Carolina. RESULTS: Individual accessibility is defined as the availability of healthcare opportunities within that individual's activity space. Access is influenced by the shape and area of an individual's activity space, the spatial distribution of opportunities, and by the spatial structures that constrain and direct movement through space; the shape and area of the activity space is partly a product of how it is conceptualized and measured. Network-derived measures improve upon the SDE by incorporating the spatial structures (roads) that channel movement. The area of the STT is primarily influenced by the location of a respondent's residence within the road network hierarchy, with residents living near primary roads having the largest activity spaces. The RNB was most descriptive of actual opportunities and can be used to examine bypassing. The area of the RTT had the strongest correlation with a healthcare destination being located inside the activity space. CONCLUSION: The availability of geospatial technologies and data create multiple options for representing and operationalizing the construct of activity space. Each approach has its strengths and limitations, and presents a different view of accessibility. While the choice of method ultimately lies in the research question, interpretation of results must consider the interrelated issues of method, representation, and application. Triangulation aids this interpretation and provides a more complete and nuanced understanding of accessibility

Research Reference Document 05/02 : Final Report Fall 2003 and Spring 2004 Maine-New Hampshire Inshore Trawl Survey

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Photon-photon correlations and entanglement in doped photonic crystals

We consider a photonic crystal (PC) doped with four-level atoms whose intermediate transition is coupled near-resonantly with a photonic band-gap edge. We show that two photons, each coupled to a different atomic transition in such atoms, can manifest strong phase or amplitude correlations: One photon can induce a large phase shift on the other photon or trigger its absorption and thus operate as an ultrasensitive nonlinear photon-switch. These features allow the creation of entangled two-photon states and have unique advantages over previously considered media: (i) no control lasers are needed; (ii) the system parameters can be chosen to cause full two-photon entanglement via absorption; (iii) a number of PCs can be combined in a network.Comment: Modified, expanded text; added reference

Removal of Technetium, Carbon Tetrachloride, and Metals from DOE Properties.

The objective of this research is to prepare, characterize, and evaluate new materials for the removal of technetium (Tc) compounds, halogenated organics, and other troublesome metals from DOE waste streams and contaminated areas. This work follows the discovery that a nanoscale form of zero-valent iron, dispersed on high surface area supports, reduces metal ions (Cr, Hg, Pb, Cd) and Re (as a surrogate for Tc) to insoluble forms faster and with higher efficiency than does unsupported iron. Liquid-liquid extraction methods are also being developed for quantitative removal of Cs from tetraphenylborate salt mixtures, which are generated in waste processing at Savannah River, and conversion to vitrifiable inorganic Cs salts

The Ursinus Weekly, November 24, 1958

Y holds seminar Nov. 19; Marriage problem is topic • Fireside chats to be held Dec. 3 at prof\u27s home • C. Carpenter has poem published in anthology • Administrative regulation • Mayes, Francis \u2762 representatives to MSGA • New pledges announced by Alpha Psi Omega • De Gaulle and France topic at second Forum of Fall semester • Who\u27s who honors 12 leading Ursinus seniors • Senior Ball to be held at Sunnybrook Dec. 5 • W.S.G.A. presents plaque to winning frosh team • Editorial: Thanksgiving • Letters to the editor • Review: Joan of Lorraine • Slightly allegorical • U.C. soccermen lose last three games; Finish 2-6-1 • Prospects for U.C. basketball team looking up • Varsity hockey finishes with 4-2-1; J.V. is 6-0-1 • Football squad drops two games 12-0, 34-6 • Sorority bids • American hist. students begin tour program • Fine art of datinghttps://digitalcommons.ursinus.edu/weekly/1372/thumbnail.jp

Comparisons of Two Proteomic Analyses of Non-Mucoid and Mucoid Pseudomonas aeruginosa Clinical Isolates from a Cystic Fibrosis Patient

Pseudomonas aeruginosa chronically infects the lungs of cystic fibrosis (CF) patients. The conditions in the CF lung appear to select for P. aeruginosa with advantageous phenotypes for chronic infection. However, the mechanisms that allow the establishment of this chronic infection have not been fully characterized. We have previously reported the transcriptional analysis of two CF isolates strains 383 and 2192. Strain 2192 is a mucoid, alginate overproducing strain whereas strain 383 is non-mucoid. Mucoid strains are associated with chronic infection of the CF lung and non-mucoid strains are the typical initially infecting isolates. To elucidate novel differences between these two strains, we employed two methods of shotgun proteomics: isobaric tags for relative and absolute quantitation (iTRAQ) and two-dimensional gel electrophoresis (2-DE). iTRAQ compares the amount of protein between samples and relies on protein abundance, while 2-DE gel electrophoresis depends on selection of separated protein spots. For both these methods, mass spectrometry was then used to identify proteins differentially expressed between the two strains. The compilation of these two proteomic methods along with Western blot analysis revealed proteins of the HSI-I operon of the type 6 secretion system, showed increased expression in 383 compared to 2192, confirming the our previous transcriptional analysis. Proteomic analysis of other proteins did not fully correlate with the transcriptome but other differentially expressed proteins are discussed. Also, differences were noted between the results obtained for the two proteomic techniques. These shotgun proteomic analyses identified proteins that had been predicted only through gene identification; we now refer to these as “proteins of unknown functions” since their existence has now been established however their functional characterization remains to be elucidated

The Ursinus Weekly, June 7, 1907

Baccalaureate sermon • Alumni oration • Junior oratorical contest • Class Day exercises • Commencement day • Editorial: The seniors; Vacation • Society notes • Personals • Donation to Library • Alumni • Charmidean banquet • Spiritual conference • Literary Supplement: Farewell song to the Class of 1907; The power of music; Uses of literature; The heredity of the twentieth century; Greater love hath no man; The history and plan of agricultural education; Jerry; A plea for the better management of railroadshttps://digitalcommons.ursinus.edu/weekly/2948/thumbnail.jp

Earthworm effects on the incorporation of litter C and N into soil organic matter in a sugar maple forest

To examine the mechanisms of earthworm effects on forest soil C and N, we double-labeled leaf litter with C-13 and N-15, applied it to sugar maple forest plots with and without earthworms, and traced isotopes into soil pools. The experimental design included forest plots with different earthworm community composition (dominated by Lumbricus terrestris or L. rubellus). Soil carbon pools were 37% lower in earthworm-invaded plots largely because of the elimination of the forest floor horizons, and mineral soil C:N was lower in earthworm plots despite the mixing of high C:N organic matter into soil by earthworms. Litter disappearance over the first winter-spring was highest in the L. terrestris (T) plots, but during the warm season, rapid loss of litter was observed in both L. rubellus (R) and T plots. After two years, 22.0% +/- 5.4% of C-13 released from litter was recovered in soil with no significant differences among plots. Total recovery of added C-13 (decaying litter plus soil) was much higher in no-worm (NW) plots (61-68%) than in R and T plots (20-29%) as much of the litter remained in the former whereas it had disappeared in the latter. Much higher percentage recovery of N-15 than C-13 was observed, with significantly lower values for T than R and NW plots. Higher overwinter earthworm activity in T plots contributed to lower soil N recovery. In earthworm-invaded plots isotope enrichment was highest in macroaggregates and microaggregates whereas in NW plots silt plus clay fractions were most enriched. The net effect of litter mixing and priming of recalcitrant soil organic matter (SOM), stabilization of SOM in soil aggregates, and alteration of the soil microbial community by earthworm activity results in loss of SOM and lowering of the C:N ratio. We suggest that earthworm stoichiometry plays a fundamental role in regulating C and N dynamics of forest SOM