655 research outputs found

    The Railroad’s Impact on Land Values in the Upper Great Plains at the Closing of the Frontier

    Get PDF
    We show that the impact of transportation improvements on land values is complex with a direct, positive relationship on the price of land and also a positive relationship with the ratio of improved acres to total acres, another important influence on the per acre price of land. We construct a two step estimation that removes the impact of transportation outlets on the ratio of improved to total acres before including the transportation variables and the adjusted ratio variable as independent variables in a regression on price per acre. This estimation gives us the expected positive impact of railroads on land price. We also use Box-Cox regressions to show the semi-log form, a common model specification, may be inappropriate for our data and possibly then for other land price research.Box-Cox, Railroads, Great Plains

    Teaching Bank Runs Through Films

    Get PDF
    The author advocates the use of films to supplement textbook treatments of bank runs and panics in money and banking or general banking classes.  Modern students, particularly those in developed countries, tend to be unfamiliar with potential fragilities of financial systems such as a lack of deposit insurance or other safety net mechanisms.  Films provide a dramatic example of the panic and uncertainty experienced by depositors and banks during bank runs.  Students learn the value of deposit insurance and the types of informational asymmetries safety net mechanisms overcome.  The author provides examples of assignments given in the past and possible extensions.

    Another Curriculum Requirement? Quantitative Reasoning In Economics: Some First Steps

    Get PDF
    In this paper, we describe first steps toward focusing on quantitative reasoning in an intermediate microeconomic theory course. We find student attitudes toward quantitative aspects of economics improve over the duration of the course (as we would hope). Perhaps more importantly, student attitude toward quantitative reasoning improves, in general. This result suggests that economics courses should be considered for inclusion as part of any effort to incorporate quantitative reasoning across the curriculum

    The controlled ecological life support system Antarctic analog project: Analysis of wastewater from the South Pole Station, Antarctica, volume 1

    Get PDF
    The Controlled Ecological Life Support system (CELSS) Antarctic Analog Project (CAAP) is a joint National Science Foundation (NSF) and NASA project for the development, deployment and operation of CELSS technologies at the Amundsen-Scott South Pole Station. NASA goals are operational testing of CELSS technologies and the conduct of scientific studies to facilitate technology selection and system design. The NSF goals are that the food production, water purification, and waste treatment capabilities which will be provided by CAAP will improve the quality of life for the South Pole inhabitants, reduce logistics dependence, and minimize environmental impacts associated with human presence on the polar plateau. This report presents an analysis of wastewater samples taken from the Amundsen-Scott South Pole Station, Antarctica. The purpose of the work is to develop a quantitative understanding of the characteristics of domestic sewage streams at the South Pole Station. This information will contribute to the design of a proposed plant growth/waste treatment system which is part of the CELSS Antarctic Analog Project (CAAP)

    Hypertension, Chronic Kidney Disease, and Renal Pathology in a Child with Hermansky-Pudlak Syndrome

    Get PDF
    We report a child with Hermansky-Pudlak Syndrome (HPS) and chronic kidney disease (stage II) with histological diagnosis of focal segmental glomerulosclerosis (FSGS). A 15-year-old male of Puerto Rico ancestry with history of HPS, hypertension (HTN), asthma, obesity, and chronic kidney disease (CKD) stage II presented with new-onset proteinuria without edema. His blood pressure had been controlled, serum creatinine had been 0.9–1.4 mg/dL, and first morning urine protein/creatinine ratio (UPC) ranged from 0.2 to 0.38. Due to persistent nonorthostatic proteinuria with CKD, renal biopsy was performed and FSGS (not otherwise specified) with chronic diffuse tubulopathy (tubular cytoplasmic droplets) and acute tubular injury was reported. Ceroid-like material is known to infiltrate tissues (i.e., lungs, colon, and kidney) in HPS, but the reason for the renal insufficiency is unknown. Nonspecific kidney disease and in one adult case IgA nephropathy with ANCA-positive glomerulonephritis have previously been reported in patients with Hermansky-Pudlak syndrome. To our knowledge, we report the first pediatric renal pathology case of HPS associated with CKD. This paper discusses presentation and management of renal disease in HPS

    Multilfiltration Bed Replacement (MFBR) System for the International Space Station using Aquaporin Membranes and Humidity Condensate Ersatz Wastewater

    Get PDF
    The Multifiltration Bed system in the International Space Station (ISS) Water Processor Assembly (WPA) needs to be improved by reducing or eliminating the usage rate of expendable media, removing dimethylsilanediol (DMSD), and reducing the overall system mass. The WPA contains two multifiltration beds, each with a mass of approximately 50 kg. Reducing the mass of the WPA is an important part of evolving the ISS system for future exploration missions. The Multifiltration Bed Replacement (MFBR) technology is based on biomimetic membranes, which derive their unique characteristics from aquaporins, or water channel proteins. Aquaporin membranes were commercialized by the company Aquaporin AS. Tests were conducted using the Aquaporin Inside Hollow Fiber Module to determine the maximum water recovery ratio and membrane life. Samples were analyzed for total organic carbon (TOC), DMSD, acetate, ions, and volatiles such as ethanol and acetone. The results indicate that at a 97.498.1 water recovery ratio, the membrane module can reject approximately 50 of the TOC and specific conductance using the simulated ISS MSFC humidity condensate ersatz. Additionally, the life of the membrane was determined to be a minimum of 7103 hours

    Use of mycophenolate mofetil in steroid-dependent and -resistant nephrotic syndrome

    Full text link
    Cyclosporin (Cs-A) is an effective treatment for difficult cases of nephrotic syndrome (NS), but its use can be complicated by renal toxicity and a high incidence of relapses after withdrawal. We reviewed the charts of 10 Cs-A-dependent patients and 4 patients with steroid-dependent nephrotic syndrome (SDNS) not previously treated with Cs-A therapy. All patients had persistent NS, even after prior treatment with oral cyclophosphamide. Of 10 patients treated with Cs-A, 4 had surveillance renal biopsies consistent with Cs-A toxicity, and 8 of 10 had interstitial fibrosis prior to mycophenolate mofetil (MMF). Patients were treated with MMF, at 1,200 mg/m 2 per day, in an attempt to allow weaning of Cs-A and/or steroid therapy, and reduce the frequency of relapses. Overall, a significant decrease in frequency of relapses was noted after initiation of MMF therapy. In addition, 5 patients were weaned off Cs-A by 1–2 years of follow-up. One patient was weaned off Cs-A and MMF, and remained in complete remission. However, the subgroup of patients with frequently relapsing SDNS not treated with Cs-A appeared to have a reduction in the number of relapses while on MMF that did not reach statistical significance. Two patients with intractable steroid-resistant NS continued to relapse repeatedly on MMF and Cs-A therapy. We conclude that in this small, single-center, uncontrolled experience, MMF therapy in patients with Cs-A-dependent NS appears to be effective in reducing Cs-A exposure. In addition, MMF appears to significantly decrease the frequency of relapses in this patient population. Further controlled studies are warranted to better define the potential efficacy and side effects of long-term MMF therapy in this setting.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47822/1/467_2003_Article_1175.pd

    A new outcome measure for LUTS: Symptoms of Lower Urinary Tract Dysfunction Research Network Symptom Index‐29 (LURN SI‐29) questionnaire

    Full text link
    AimsTo develop a representative, self‐report assessment of lower urinary tract symptoms (LUTS) for men and women, the symptoms of Lower Urinary Tract Dysfunction Research Network Symptom Index‐29 (LURN SI‐29).MethodsWomen and men seeking treatment for LUTS at one of six academic medical centers in the US were assessed at baseline, 3‐month and 12‐month intervals. Twelve‐month data on 78 LURN SI‐29 items were analyzed among 353 women and 420 men using exploratory factor analysis (EFA), with factor structure confirmed using confirmatory factor analysis (CFA). Internal consistency, reliability, and validity of the five developed scales were evaluated by assessing correlations with the American Urological Association Symptom Index (AUA‐SI), the genitourinary pain index (GUPI), and the Pelvic Floor Distress Inventory‐20 (PFDI‐20), and by examining expected sex differences in scores.ResultsEFA results (n = 150 women; 150 men) produced an interpretable eight‐factor solution, with three of the factors comprised of dichotomous items addressing LUTS‐associated sensations. The remaining five factors, confirmed with CFA in an independent sample of 473 participants, produced five scales: incontinence, urgency, voiding difficulty, bladder pain, and nocturia. Subscales and total LURN SI‐29 scores were correlated as expected with AUA‐SI, GUPI, and PFDI‐20. LURN SI‐29 scores also performed as expected in differentiating men from women based upon clinically expected differences, with men reporting more voiding difficulties and nocturia, and women reporting more urgency and incontinence.ConclusionsThe LURN SI‐29 questionnaire has the potential to improve research and clinical outcome measurement for both men and women with LUTS.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150585/1/nau24067.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150585/2/nau24067_am.pd
    corecore