ユーザ嗜好に基づく情報検索・フィルタリングに関する研究

制度:新 ; 文部省報告番号:乙2057号 ; 学位の種類:博士(工学) ; 授与年月 日:2006/12/21 ; 早大学位記番号:新435

A Comparative Look at Immigration and Human Capital Assessment

This article examines the formation of an immigration policy designed to build up the skill and human capital of a country. We discuss how the process of selecting economic-stream migrants could be designed to yield economic benefits to the host country. Part I examines the theoretical considerations involved in framing a policy that governs economic-stream immigration. In this section, we outline the goals that a host country seeks to achieve in selecting these migrants and propose important elements of a selection scheme. Part II takes a comparative look at existing points-based schemes for selecting economic migrants, focusing on Canada and Australia. Part III briefly discusses practical barriers to implementing such a system in the United States. The article concludes that the United States should enact a points-based system for selecting economic-stream migrants. It is impossible to cover this subject exhaustively in one article. For that reason, this article only discusses the immigration of high-skilled workers, not low-skilled or agricultural workers. We also only discuss permanent immigration, not temporary workers. Finally, as others studying this area know, we are all handicapped by a lack of good statistical or economic data. We discuss several studies that have sought to evaluate the economic success of economic-stream migrants over time, but these studies are limited in scope, the time period covered, and their ability to establish a clear link between selection criteria and the economic results that were measured. Thus, our recommendations should be considered skeptically. As discussed below, we are not sure what has worked best in other countries, let alone how policy changes would work in the U.S. context

Development of methods for the determination of bismuth and thallium in geological materials and their significance for the Cretaceous-Tertiary boundary event : a thesis presented in partial fulfilment for the degree of Master of Science, Department of Chemistry and Biochemistry, Massey University, New Zealand

Solvent extraction methods have been developed for the determination of thallium and bismuth in rocks. The method for thallium is based on the extraction of the chlorocomplex into methylisobutyl ketone followed by removal of the interfering chloride ion as insoluble silver chloride. The method for bismuth is based on the extraction of a stable metal complex with ammonium pyrrolidine dithiocarbamate into methylisobutyl ketone. Both elements are analysed on a electrothermal graphite furnace atomic absorption spectrometer. Tests on the efficiencies of the methods showed a good precision and accuracy with limits of detection of 9.5 ng/ml (ppb) for thallium and 20 ng/ml (ppb) for bismuth. Recovery studies on synthetic samples showed recoveries of >99.9% for both elements. A geochemical study was performed on a Cretaceous-Tertiary boundary site located near Flaxbourne River, Ward, New Zealand. Investigations were carried out to determine the enrichment of thallium and bismuth in the stratigraphic column. The results show a good correlation between the iridium and thallium content throughout the rock sequence, but the samples have very low bismuth contents. This is indicative of the different geochemical behavior of bismuth to other chalcophiles. These findings do not contradict the impact theory initially hypothesized by Alvarez et al. (1980), and instead suggest that bismuth's mobility and solubility are far greater than those of thallium and the other chalcophile elements enriched in the Flaxbourne River sequence. This results in the leaching of bismuth from the stratigraphic column by sea water after deposition

Clinical outcomes of prophylactic Damus-Kaye-Stansel anastomosis concomitant with bidirectional Glenn procedure

ObjectiveWe evaluated prophylactic Damus-Kaye-Stansel (DKS) anastomosis in association with the timing of a bidirectional Glenn (BDG) procedure as second-stage palliation aiming at Fontan completion to prevent late systemic ventricular outflow tract obstruction.MethodsBetween 1996 and 2005, 25 patients (14 boys; median age, 12 months) underwent a BDG procedure concomitant with DKS anastomosis. All had a systemic ventricular outflow tract through an intraventricular communication or morphologically developed subaortic conus and had previously undergone pulmonary artery banding. Enlargement of intraventricular communication and/or resection of a subaortic conus were not performed before or during the operation.ResultsTwenty-one (84%) patients subsequently underwent a Fontan operation, with a follow-up period of 6.8 ± 1.9 years (range, 4-11 years), with no mortalities after the Fontan operation. Cardiac catheterization showed that systemic ventricular end-diastolic volume was significantly decreased from 187% ± 74% of normal before BDG to 139% ± 35% after (P = .038) and to 73% ± 14% at 4.3 years after the Fontan operation (P < .001). However, the pressure gradient across the systemic ventricular outflow tract remained at 0.5 ± 0.8 mm Hg after DKS anastomosis and 0.6 ± 2.3 mm Hg at 4.6 years after the Fontan operation. None of the patients showed more than moderate aortic or neoaortic regurgitation, except 1 who progressed to pulmonary regurgitation after DKS anastomosis and required a reoperation for a systemic ventricular outflow tract. No anatomic properties affected late neoaortic valve function.ConclusionsRegardless of a significant reduction in systemic ventricular volume, DKS anastomosis concomitant with a BDG procedure shows promise for a nonobstructive systemic ventricular outflow tract after a Fontan operation

Outcomes of 1½- or 2-ventricle conversion for patients initially treated with single-ventricle palliation

ObjectiveAs outcomes for the Fontan procedure have improved, it has become more difficult to select between a single-ventricle repair or biventricular repair for patients with complex anatomy and 2 ventricles. However, late complications after the Fontan procedure remain a concern. Our strategy, which has favored an aggressive preferential approach for biventricular repair in these patients, has also been applied to patients initially treated on a single-ventricle track elsewhere.MethodsNine patients (4 male patients) who had previously undergone the Fontan procedure (n = 3) or bidirectional cavopulmonary shunting (n = 6) with intent for a later Fontan procedure were referred to our center for complex 1½- or 2-ventricle repair over the last 10 years. Indications for conversion in these patients were protein-losing enteropathy (n = 2), pulmonary arteriovenous malformation (n = 1), and preference for biventricular anatomy (n = 6). The conversion mainly consisted of takedown of the Fontan procedure or bidirectional cavopulmonary shunt connection, reconstruction of 1 or both of venae cavae, creation of an intraventricular pathway for left ventricular output, and placement of a right ventricle–pulmonary artery conduit (Rastelli-type operation).ResultsFive patients underwent 1½-ventricle repair, and 4 had complete biventricular repair. Median cardiopulmonary bypass and aortic crossclamp times were 202 minutes (range, 169–352 minutes) and 129 minutes (range, 100–168 minutes), respectively. There were 2 early deaths and 1 late death. At a median follow-up of 27 months (range, 3.3–99.8 months), all survivors are in New York Heart Association class I.ConclusionsPatients initially treated with intent to perform single-ventricle palliation can be converted to 1½- or 2-ventricle physiology with acceptable outcomes

Management of ostium secundum atrial septal defect in the era of percutaneous trans-catheter device closure: 7-Year experience at a single institution

AbstractObjectivesThis study aimed to review the single institutional experience of the repair of secundum atrial septal defect (ASD) after the initiation of percutaneous trans-catheter device closure, to confirm the current management strategy and outcomes.MethodsFrom August 2005 to December 2012, a total of 1026 (659 females, age 27±21 years) consecutive patients underwent the repair of ASD. Including eight patients who converted to surgical repair, 317 patients (31%) underwent surgical repair and 709 (69%) underwent trans-catheter device closure.ResultsAn embolized device into the left atrium was surgically retrieved in one patient soon after trans-catheter device closure without any postoperative complications. The other patient developed left atrium to aorta fistula due to late erosion, and required the removal of implanted device and patch closure of fistula and ASD 3 months after trans-catheter device closure. Whereas serious central nerve system complications occurred in three patients after the surgical repair including a 75-year-old patient with postoperative transient atrial fibrillation who subsequently developed aspiration pneumonia and died; there were no mortalities and no morbidities associated with cranial nerve function after trans-catheter device closure. A number of patients approached through partial sternotomy with limited skin incision have increased per year, and the length of skin incision was 5.1±1.2cm in pediatric patients weighing less than 15kg (n=40), 6.9±1.9cm in the remaining pediatric patients (n=91), and 10.0±2.5cm in young adult females (n=10).ConclusionPercutaneous trans-catheter ASD closure was safely performed under the support of a surgical team. The cosmetic outcome of surgical closure is improving after initiation of partial sternotomy via limited skin incision for the pediatric population and young adult females. Prior to the treatment, the physicians must thoroughly inform patients and families of the advantages and disadvantages of both treatment options

Long-term outcomes after definitive repair for tetralogy of Fallot with preservation of the pulmonary valve annulus

ObjectivesThe aim of our study was to evaluate the long-term outcomes after definitive repair of tetralogy of Fallot with preservation of the pulmonary valve (PV) annulus.MethodsFrom 1989 to 2000, 84 of 222 patients (37.8%) with tetralogy of Fallot and PV stenosis underwent definitive repair with preservation of the PV annulus without right ventriculotomy. PV commissurotomy was concomitantly performed in 74 patients (88.1%). The PV was bicuspid in 56 patients (66.7%); the mean Z value was −1.2 ± 1.5 (range, −4.9 to 2.4). The mean follow-up period was 15.8 ± 5.7 years (maximum, 22.8), and follow-up data were complete for 75 patients (89.3%).ResultsThe actuarial survival and freedom from reoperation rates at 20 years was 98.6% and 95.8%. The freedom from ventricular arrhythmia at 5, 10, 15, and 20 years was 98.7%, 89.6%, 74.1%, and 58.0%, respectively. All detected ventricular arrhythmias were isolated monofocal premature ventricular contractions. Freedom from moderate or greater pulmonary regurgitation at 5, 10, 15 and 20 years was 50.4%, 44.9%, 38.4%, and 35.7%, respectively. A bicuspid PV (hazard ratio, 2.910; 95% confidence interval, 1.404-6.204, P = .004) and a Z-value of less than −2 (hazard ratio, 1.948; 95% confidence interval, 0.915-5.857; P = .034) were the risk factors for developing moderate or greater pulmonary regurgitation.ConclusionsThe long-term outcomes after definitive repair of tetralogy of Fallot with preservation of the PV annulus were excellent. Although isolated, monofocal premature ventricular contractions were frequently observed, fatal ventricular arrhythmia was not. The indication should not only be decided by the PV annulus size, but also by the valvular morphology to maintain long-term PV competency