Controlled growth strategies and the poor.

Massachusetts Institute of Technology. Dept. of Urban Studies and Planning. Thesis. 1973. M.C.P.Bibliography: leaves 122-125.M.C.P

Method for removal of nitrogen oxides from stationary combustion sources

A method for removing NO.sub.X from gas streams emanating from stationary combustion sources and manufacturing plants utilizes the injection of hydrogen peroxide into the gas stream for rapid gas-phase oxidation of NO to NO.sub.2 and water-soluble nitrogen acids HNO.sub.2 and HNO.sub.3. The nitrogen acids may be removed from the oxidized gas stream by wet scrubbing or by contact with a particulate alkaline material to form a nitrite/nitrate salt

Statistical limitations in ion imaging

In this study, we investigated the capacity of various ion beams available for radiotherapy to produce high quality relative stopping power map acquired from energy-loss measurements. The image quality metrics chosen to compare the different ions were signal-to-noise ratio (SNR) as a function of dose and spatial resolution. Geant4 Monte Carlo simulations were performed for: hydrogen, helium, lithium, boron and carbon ion beams crossing a 20 cm diameter water phantom to determine SNR and spatial resolution. It has been found that protons possess a significantly larger SNR when compared with other ions at a fixed range (up to 36% higher than helium) due to the proton nuclear stability and low dose per primary. However, it also yields the lowest spatial resolution against all other ions, with a resolution lowered by a factor 4 compared to that of carbon imaging, for a beam with the same initial range. When comparing for a fixed spatial resolution of 10 lp cm−1, carbon ions produce the highest image quality metrics with proton ions producing the lowest. In conclusion, it has been found that no ion can maximize all image quality metrics simultaneously and that a choice must be made between spatial resolution, SNR, and dose

Genetic characterization of influenza A(H3N2) viruses circulating in coastal Kenya, 2009-2017

Background Influenza viruses evolve rapidly and undergo immune driven selection, especially in the hemagglutinin (HA) protein. We report amino acid changes affecting antigenic epitopes and receptor‐binding sites of A(H3N2) viruses circulating in Kilifi, Kenya, from 2009 to 2017. Methods Next‐generation sequencing (NGS) was used to generate A(H3N2) virus genomic data from influenza‐positive specimens collected from hospital admissions and health facility outpatients presenting with acute respiratory illness to health facilities within the Kilifi Health and Demographic Surveillance System. Full‐length HA sequences were utilized to characterize A(H3N2) virus genetic and antigenic changes. Results From 186 (90 inpatient and 96 outpatient) influenza A virus‐positive specimens processed, 101 A(H3N2) virus whole genomes were obtained. Among viruses identified in inpatient specimens from 2009 to 2015, divergence of circulating A(H3N2) viruses from the vaccine strains A/Perth/16/2009, A/Texas/50/2012, and A/Switzerland/9715293/2013 formed 6 genetic clades (A/Victoria/208/2009‐like, 3B, 3C, 3C.2a, 4, and 7). Among viruses identified in outpatient specimens from 2015 to 2017, divergence of circulating A(H3N2) viruses from vaccine strain A/Hong Kong/4801/2014 formed clade 3C.2a, subclades 3C.2a2 and 3C.2a3, and subgroup 3C.2a1b. Several amino acid substitutions were associated with the continued genetic evolution of A(H3N2) strains in circulation. Conclusions Our results suggest continuing evolution of currently circulating A(H3N2) viruses in Kilifi, coastal Kenya and suggest the need for continuous genetic and antigenic viral surveillance of circulating seasonal influenza viruses with broad geographic representation to facilitate prompt and efficient selection of influenza strains for inclusion in future influenza vaccines

Survival and Recruitment of Rehabilitated Caspian Terns in Southern California

Thousands of birds are taken in by animal care centers each year for rehabilitation. Birds returned to health by some centers are banded for later identification, but very few are ever reencountered following their return to the wild. We report here, information on the post-release survival of Caspian Terns (Hydroprogne caspia) in southern California as well as on their recruitment into a local breeding population and colony site fidelity

Ponderomotive effects in multiphoton pair production

The Dirac-Heisenberg-Wigner formalism is employed to investigate electron-positron pair production in cylindrically symmetric but otherwise spatially inhomogeneous, oscillating electric fields. The oscillation frequencies are hereby tuned to obtain multiphoton pair production in the nonperturbative threshold regime. An effective mass as well as a trajectory-based semi-classical analysis are introduced in order to interpret the numerical results for the distribution functions as well as for the particle yields and spectra. The results, including the asymptotic particle spectra, display clear signatures of ponderomotive forces.Comment: 9 pages, 3 Tables, 3 Figure

The Effect of Oral Antibiotics on the Development of Community Acquired Clostridium Difficile Colitis in Medicare Beneficiaries

Clostridium difficile infection (CDI) is increasingly prevalent among community dwelling Americans. Older Americans are particularly vulnerable to community-acquired Clostridium difficile (CACD), in part to increasing use of antibiotics. We studied the association between outpatient antibiotics and CACD among Medicare beneficiaries. Case-control study utilizing a 5% sample of Medicare beneficiaries (2009-2011). Patients with CACD severe enough to warrant hospitalization were identified by a primary diagnosis code for CDI and no exposure to a healthcare environment within 90-days of admission. 1,514 CACD cases were matched to ten controls each on birth year and sex. Potential controls with exposure to healthcare environment were excluded. Outpatient oral antibiotic exposure was classified into three groups: ≤30 days, 31-60 days, or 61-90 days prior to case subject’s index admission. Metronidazole and Vancomycin were excluded because they are used to treat CDI. Multivariable models were utilized to determine the independent effect of antibiotics on the development of CACD while controlling for several patient associated characteristics. Cases of CACD had more outpatient antibiotic exposure in each time period examined: ≤30 days = 40.0% vs 8.4%; 31-60 = 10.7% vs 5.0%; and 61-90 = 5.5% vs 4.4% (all p-values \u3c 0.05). Subjects exposed to antibiotics ≤30 days prior to admission had a markedly higher risk of being admitted with CACD compared with those not exposed (OR 8.09, 95% CI 7.13, 9.19). Similarly, subjects taking antibiotics 31-60 days and 61-90 days prior to admission had increased risk of CDI admission (OR 3.65, 95% CI 3.02, 4.41) and (OR 2.06, 95% CI 1.61, 2.63) respectively. Recent exposure to outpatient oral antibiotics increases the risk of CACD among community dwelling elderly with the risk persisting as long as 90 days after exposure. Inappropriate antibiotic usage must be minimized and older Americans who require outpatient antibiotic treatment may warrant close observation for signs of CDI

Hydrogeologic Characterization of the Saline Aquifers, East Texas Basin- Implications to Nuclear Waste Storage in East Texas salt Domes

Groundwaters in the deep aquifers (Nacatoch to Travis Peak) range in salinity from 20,000 to over 200,000 mg/L. Based on their isotopic compositions, they were originally recharged as continental meteoric waters. Recharge probably occurred predominantly during the Cretaceous time; therefore, the waters are very old. Because the basin has not been uplifted, there are no extensive recharge or discharge zones. The flanks of domes and radial faults associated with domes may function as localized discharge points. Both the water chemistry and the hydraulic pressures for the aquifers suggest that the basin can be subdivided into two major aquifer systems: (1) the upper Cretaceous aquifers (Woodbine and shallower) which are hydrostatic and (2) the deep lower Cretaceous and deeper formations (Glen Rose, Travis Peak, and older units), which are slightly overpressured. The source of sodium and chloride in the saline waters is considered to be from salt dome dissolution. Most of the dissolution occurred during the Cretaceous. Chlorine-36 analyses suggest that dome solution is not presently occurring. Salinity cross sections across individual domes do not indicate that ongoing solution is an important process. The major chemical reactions in the saline aquifers are dome dissolution, albitization, and dedolomitization. Albitization and dedolomitization are important only in the deeper formations. The high Na concentrations in the deeper aquifer system result in the alteration of plagioclase to albite and the release of Ca into solution. The increase in Ca concentrations causes a shift in the calcite/dolomite equilibrium. The increase in Mg results from dissolution of dolomite.Bureau of Economic Geolog

Rotational Broadening and Doppler Tomography of the Quiescent X-Ray Nova Centaurus X-4

We present high and intermediate resolution spectroscopy of the X-ray nova Centaurus X-4 during its quiescent phase. Our analysis of the absorption features supports a K3-K5V spectral classification for the companion star, which contributes approximately 75 % of the total flux at Halpha. Using the high resolution spectra we have measured the secondary star's rotational broadening to be V_rot*sin(i) = 43 +/- 6 km/s and determined a binary mass ratio of q=0.17 +/- 0.06. Combining our results for K_2 and q with the published limits for the binary inclination, we constrain the mass of the compact object and the secondary star to the ranges 0.49 < M_1 < 2.49 Msun and 0.04 < M_2 < 0.58 Msun. A Doppler image of the Halpha line shows emission coming from the secondary star, but no hotspot is present. We discuss the possible origins of this emission.Comment: 10 pages, 4 figures, accepted by MNRA

Evaluation of In Vitro Virulence Characteristics of the Genus Pandoraea in Lung Epithelial Cells

Pandoraea species are emerging opportunistic pathogens capable of causing chronic lung infections in cystic fibrosis patients. This study examined the interactions of 17 Pandoraea isolates from the five identified species (Pandoraea apista, Pandoraea norimbergensis, Pandoraea pulmonicula, Pandoraea sputorum and Pandoraea pnomenusa) plus two Pandoraea genomospecies isolates with lung epithelial cells and their ability to form biofilms in vitro. Only three isolates showed an ability to invade A549 lung epithelial cells, and only one isolate was able to form biofilms. In contrast, all isolates triggered a pronounced pro-inflammatory response, with elevation of both interleukin (IL)-6 (two- to 19-fold) and IL-8 (10- to 50-fold) above that observed for a control strain of Escherichia coli. This property is likely to be a major factor in the pathogenesis of the genus