Investigation of single crystal ferrite thin films

Materials suitable for use in magnetic bubble domain memories were developed for aerospace applications. Practical techniques for the preparation of such materials in forms required for fabrication of computer memory devices were considered. The materials studied were epitaxial films of various compositions of the gallium-substituted yttrium gadolinium iron garnet system. The major emphasis was to determine their bubble properties and the conditions necessary for growing uncracked, high quality films

Nitrous oxide in fresh water systems: An estimate for the yield of atmospheric N2O associated with disposal of human waste

The N2O content of waters in the Potomac and Merrimack Rivers was measured on a number of occasions over the period April to July 1977. The concentrations of dissolved N2O exceeded those which would apply in equilibrium with air by factors ranging from about 46 in the Potomac to 1.2 in the Merrimack. Highest concentrations of dissolved N2O were associated with sewage discharges from the vicinity of Washington, D. C., and analysis indicates a relatively high yield, 1.3 to 11%, for prompt conversion of waste nitrogen to N2O. Measurements of dissolved N2O in fresh water ponds near Boston demonstrated that aquatic systems provide both strong sources and sinks for atmospheric N2O

A Self-Consistent Model of the Circumstellar Debris Created by a Giant Hypervelocity Impact in the HD172555 System

Spectral modeling of the large infrared excess in the Spitzer IRS spectra of HD 172555 suggests that there is more than 10^19 kg of sub-micron dust in the system. Using physical arguments and constraints from observations, we rule out the possibility of the infrared excess being created by a magma ocean planet or a circumplanetary disk or torus. We show that the infrared excess is consistent with a circumstellar debris disk or torus, located at approximately 6 AU, that was created by a planetary scale hypervelocity impact. We find that radiation pressure should remove submicron dust from the debris disk in less than one year. However, the system's mid-infrared photometric flux, dominated by submicron grains, has been stable within 4 percent over the last 27 years, from IRAS (1983) to WISE (2010). Our new spectral modeling work and calculations of the radiation pressure on fine dust in HD 172555 provide a self-consistent explanation for this apparent contradiction. We also explore the unconfirmed claim that 10^47 molecules of SiO vapor are needed to explain an emission feature at 8 um in the Spitzer IRS spectrum of HD 172555. We find that unless there are 10^48 atoms or 0.05 Earth masses of atomic Si and O vapor in the system, SiO vapor should be destroyed by photo-dissociation in less than 0.2 years. We argue that a second plausible explanation for the 8 um feature can be emission from solid SiO, which naturally occurs in submicron silicate "smokes" created by quickly condensing vaporized silicate.Comment: Accepted to the Astrophysical Journa

Plastic surgical techniques in the repair of vesicovaginal fistulas: A review

A variety of plastic surgical techniques may be used in the repair of vesicovaginal fistulas. The indication for their use include: (a) diameter greater than 4 cm; (b) involvement of the bladder neck/proximal urethra; (c) radiation-induced fistulas; and (d) previous failed repair(s). In the developing world the vast majority of complex fistulas are caused by obstetric trauma; elsewhere they occur mainly following radiotherapy or radical surgery for gynecologic malignancy. The majority of complex fistulas requiring tissue donation may be effectively treated using a vaginal approach and a modified Martius graft. There is probably little or no advantage in encorporating bulbocavernosus muscle fibers in this graft. Although some concern exists regarding the long-term viability of these grafts in radiation-induced fistulas, in view of the relatively simple operative technique, together with the low associated morbidity, modified Martius grafts may be deemed suitable for first-time repairs. The gracilis muscle graft should be considered next in cases of exclusive transvaginal repair. The omental graft is undoubtedly the most versatile: it can be used in both abdominal and combined abdominovaginal procedures. The recently described posterosuperior sliding bladder flaps warrant further evaluation. For most fistulas involving the bladder neck/proximal urethra, there is no clear advantage in bladder flap reconstruction over vaginal flap reconstruction, the latter being augmented by an anti-stress incontinence procedure were appropriate. When continent urinary diversion is required, the Indiana pouch appears preferable to the Kock pouch; ureterosigmoidostomy is, however, technically and culturally more acceptable in these circumstances in the developing world.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45898/1/192_2004_Article_BF00372740.pd

Duration of disease does not equally influence all aspects of quality of life in Parkinson’s disease

Health related quality of life (HRQoL) is negatively impacted in patients suffering from Parkinsons disease (PD). For the specific components that comprise HRQoL, the relationship between clinical variables, such as disease duration, is not fully characterized. In this cross-sectional study (n=302), self-reported HRQoL on the Parkinsons Disease Questionnaire (PDQ-39) was evaluated as a global construct as well as individual subscale scores. HRQoL was compared in three groups: those within 5years of diagnosis, those within 6-10years of diagnosis, and those greater than 11years since diagnosis. Non-parametric analyses revealed lower HRQoL with increasing disease duration when assessed as a global construct. However, when subscales were evaluated, difficulties with bodily discomfort and cognitive complaints were comparable in individuals in the 1-5years and 6-10year duration groups. Exploratory regression analyses suggested disease duration does explain unique variance in some subscales, even after controlling for Hoehn and Yahr stage and neuropsychiatric features. Our findings show that HRQoL domains in PD patients are affected differentially across the duration of the disease. Clinicians and researchers may need to tailor interventions intended to improve HRQoL at different domains as the disease progresses

The relation of the true conjugate to maternal height and obstetric performance in Ghanaians

The true conjugate was determined intraoperatively with a caliper in 114 Ghanaian women and was correlated with their height, obstetric performance and fetal dimensions. Those patients undergoing cesarean section for cephalopelvic disproportion (Group Ia) were found to have a significantly shorter mean true conjugate (9.54 cm +/- 0.63 S.D.) and mean body height (152.68 cm +/- 5.46 S.D.) and a smaller true conjugate -- fetal biparietal diameter difference (10.93 mm) than those who had no cephalopelvic disproportion (Group Ib) and whose mean measurements were 10.61 cm +/- 0.81 S.D., 157.20 cm +/- 5.69 S.D. and 21.50 mm, respectively (P = 0.0001). Recommendations for appropriate referral of rural clinic patients and for selection of patients for repeat cesarean sections are based on the above findings.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28033/1/0000472.pd

Geographically touring the eastern bloc: British geography, travel cultures and the Cold War

This paper considers the role of travel in the generation of geographical knowledge of the eastern bloc by British geographers. Based on oral history and surveys of published work, the paper examines the roles of three kinds of travel experience: individual private travels, tours via state tourist agencies, and tours by academic delegations. Examples are drawn from across the eastern bloc, including the USSR, Poland, Romania, East Germany and Albania. The relationship between travel and publication is addressed, notably within textbooks, and in the Geographical Magazine. The study argues for the extension of accounts of cultures of geographical travel, and seeks to supplement the existing historiography of Cold War geography

Bulk Properties of Isentropic Mixing into the Tropics in the Lower Stratosphere

Timescales for mixing of midlatitude air into the tropical lower stratosphere are deduced from observations of long-lived tracers N2O and CCl3F. Bulk mixing between tropical and midlatitude regions is assumed to be isentropic and relatively slow compared with local mixing within each region. The mean value of the mixing timescale ranges from 12 to 18 months near 20 km. There is a tendency for shorter mixing times at higher and lower altitudes, although vertical profiles of mixing cannot be definitively established by the data. A more robust quantity is given by the fraction of midlatitude air entrained into the tropical upwelling region. Implied mixing fractions exceed 50% above 22 km