Unified Quantum Mechanical Picture for Confined Spinons in Dimerized and Frustrated Spin S=1/2 Chains

A quantum mechanical picture is presented to describe the behavior of confined spinons in a variety of S=1/2 chains. The confinement is due to dimerization and frustration and it manifests itselfas a nonlinear potential V(x)~ |x|^b, centered at chain ends (b <= 1) or produced by modulation kinks (b > 1). The calculation extends to weak or zero frustration some previous ideas valid for spinons in strongly frustrated spin chains. The local magnetization patterns of the confined spinons are calculated. A (minimum) enhancement of the local moments of about 11/3 over a single S=1/2 is found. Estimates for excitation energies and binding lengths are obtained.Comment: 11.5 pages, Revtex, 10 figures included, accepted by Euro. Phys. J. B final version including some changes, several references adde

The Effects of Gender and Self Construal on Perception of Racism

When looking into the idea of if one\u27s gender and their self-construal has an effect on how they perceive racism, we hypothesize that women will take a more interdependent self-construal and men will take a more independent self-construal. Based on how they identify, we believe that those in the interdependent condition will perceive more racism and those in the independent condition will perceive less racism

Development of a multikilowatt ion thruster power processor

A feasibility study was made of the application of silicon-controlled, rectifier series, resonant inverter, power conditioning technology to electric propulsion power processing operating from a 200 to 400 Vdc solar array bus. A power system block diagram was generated to meet the electrical requirements of a 20 CM hollow cathode, mercury bombardment, ion engine. The SCR series resonant inverter was developed as a primary means of power switching and conversion, and the analog signal-to-discrete-time-interval converter control system was applied to achieve good regulation. A complete breadboard was designed, fabricated, and tested with a resistive load bank, and critical power processor areas relating to efficiency, weight, and part count were identified

Grown-in defects and defects produced by 1-Me electron irradiated in Al0.3Ga0.7As P-N junction solar cells

Studies of grown-in defects and defects produced by the one-MeV electron irradiation in Al sub 0.3 Ga sub 0.7As p-n junction solar cells fabricated by liquid phase epitaxial (LPE) technique were made for the unirradiated and one-MeV electron irradiated samples, using DLTS and C-V methods. Defect and recombination parameters such as energy level, defect density, carrier capture cross sections and lifetimes were determined for various growth, annealing, and irradiation conditions

Measuring Successful Treatment of Irritable Bowel Syndrome: Is “Satisfactory Relief ” Enough?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75081/1/j.1572-0241.2006.00519.x.pd

Evidence-Based Medicine (EBM) in Practice: Understanding Tests of Heterogeneity in Metaanalysis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73071/1/j.1572-0241.2005.50452.x.pd

Knowledge of hepatitis C screening and management by internal medicine residents: trends over 2 years

Over 2 million people in the United States are infected with hepatitis C, and there has been an explosion in knowledge regarding this disease in the last decade. Internal medicine residents must be able to identify patients at risk for hepatitis C and institute appropriate diagnostic testing and referral of these patients. Methods : A survey regarding hepatitis C risk factors and the management of hepatitis C patients was administered on three occasions over 15 months (time 0, 1 month, and 15 months) to members of a large university-based internal medicine residency. Results : During the study period 59 residents completed all three surveys. Less than half of the residents (39%) ask patients about hepatitis C risk factors. Only 58% reported that they would refer a hepatitis C antibody positive patient with elevated liver enzymes to a subspecialist on the initial survey. The residents who did not refer patients cited low response rates, high side-effect profiles, and the high cost of therapy as reasons for not referring the patient. There was significant improvement (58% vs 78%, p < 0.01 ) in the rate of patient referral during the 15-month study period but no substantial improvement in the other knowledge deficits. Conclusions : The knowledge base of the internal medicine residents about hepatitis C screening and management is suboptimal. New, more effective hepatitis C education programs for internal medicine residents should be initiated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75407/1/j.1572-0241.2002.05708.x.pd

The epidemiology of irritable bowel syndrome in North America: a systematic review 1

The aim of this study was to systematically review published literature about the prevalence, incidence, and natural history of irritable bowel syndrome (IBS) in North America. Methods : A computer-assisted search of MEDLINE, EMBASE, and Current Contents/Science Edition databases was performed independently by two investigators. Study selection criteria included: 1) North American population-based sample of adults; 2) objective diagnostic criteria for IBS ( i.e. , Rome or Manning criteria); and 3) publication in full manuscript form in English. Eligible articles were reviewed in a duplicate and independent manner. Data extracted were converted into individual tables and presented in descriptive form. Results : The prevalence of IBS in North America ranges from 3% to 20%, with most prevalence estimates ranging from 10% to 15%. The prevalences of diarrhea-predominant and constipation-predominant IBS are both approximately 5%. Published prevalence estimates by gender range from 2:1 female predominance to a ratio of 1:1. Constipation-predominant IBS is more common in female individuals. The prevalence of IBS varies minimally with age. No true population-based incidence studies or natural history studies were found. In one cohort surveyed on two occasions 1 yr apart, 9% of subjects who were free of IBS at baseline reported IBS at follow-up producing an onset rate of 67 per 1000 person-years. In all, 38% of patients meeting criteria for IBS did not meet IBS criteria at 1-yr follow-up. Conclusion : Approximately 30 million people in North America meet the diagnostic criteria for IBS. However, data about the natural history of IBS is quite sparse and renewed efforts should be focused at developing appropriately designed trials of the epidemiology of IBS.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72339/1/j.1572-0241.2002.05913.x.pd

Natural history of irritable bowel syndrome

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73897/1/j.1365-2036.2004.01929.x.pd

The utility of diagnostic tests in irritable bowel syndrome patients: a systematic review

The aim of this study was to determine the pretest probability of organic GI disease and the accuracy of diagnostic tests for organic GI disease in patients who meet symptom-based criteria for irritable bowel syndrome (IBS). METHODS : After a comprehensive literature search for studies examining the accuracy of diagnostic tests for organic GI disease among patients who meet symptom-based criteria for IBS, two independent observers qualitatively assessed the methodology of selected studies and extracted data. Data on the pretest probability of organic GI disease in this population and the accuracy of currently recommended diagnostic tests were converted to descriptive tables. RESULTS : Among patients meeting symptom-based criteria for IBS, the pretest probability of inflammatory bowel disease, colorectal cancer, or infectious diarrhea is less than 1%. Currently recommended diagnostic tests rarely identify organic GI disease in patients fulfilling symptom-based criteria for IBS. However, the pretest probability of celiac disease in patients meeting symptom-based criteria for IBS was 10 times higher than the prevalence of celiac disease in the general population. CONCLUSION : There is insufficient evidence to recommend the routine performance of a standardized battery of diagnostic tests in patients who meet symptom-based criteria for IBS. Based upon the increased pretest probability of celiac disease, routine performance of serological tests for celiac disease may be useful in this patient population, though additional study is needed in this area.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72511/1/j.1572-0241.2002.07027.x.pd