Job displacement effects of Canadian immigrants by country of origin and occupation

"Some previous Canadian studies have shown that considering the labor market as a whole and also pooling all immigrants as a group, immigrants do not have any job displacement effects on the Canadian born. This study presents some new evidence. It disaggregates immigrants by country of origin and by occupation groups and provides an analysis of job displacement effects of immigrants on the native-born Canadians by these dimensions. The study finds that (1) U.S. immigrants and the Canadians are substitutes [for] competing groups in the labor market and the effect is quite significant; (2) Canadians and Europeans are competing groups in certain occupations, while they have complementary skills in others; and (3) immigrants from the Third World and the Canadians are slightly competing groups in certain occupations."     

Interethnic marriage: identifying the second generation in Australia

"Studies in Australia show that an increasing proportion of the population have ancestors from more than one country. Evidence regarding differences in the marriage patterns of first and second generation migrants has been restricted in scope as published marriage registration data includes only birthplace of partners. Marriage registration records include information about the birthplace of parents of partners, but is available only through specially produced tabulations. Changes in the census for 1986 and 1991 make it possible to identify the second generation in households, and this article examines the use of census data as an alternative to marriage registration records in tracing changes in intermarriage patterns and differences between urban and rural areas."     

Population estimates for Bangladesh: The use of a specific transitional population model

Summary The development of population in Bangladesh was affected by a succession of man-made and natural calamities, such as the Bengal Famine of 1943, refugee movements following the partition of India and Pakistan in 1947, devastating floods and cyclones around 1970, and the military action during the war of liberation. Though there had been a tradition of census taking and vital registration in Bangladesh, as part of the Indian sub-continent, extending for over a century, vital registration was so deficient as to be almost valueless, and there were gross misstatements of age and under-enumeration in the censuses. In the census of 1941, on the other hand, political manoeuvring led to a substantial overcount of the population. In this paper, Bangladesh population trends are studied within the broader framework of the subcontinent, taking account of plausible differentials. A considerable element of uncertainty was introduced into growth trends as a result of variations in the completeness of census-taking and of unrecorded refugee and labour movements across open land borders. In this connection the substantial inflationary bias associated with techniques of population estimation using the dual record system is discussed. The application of stable population models is even less justified in Bangladesh with its history of declining mortality. A transitional age structure model was constructed on the basis of the information available on declining mortality and accelerating growth and the model was made even more specific by modifications which took care of the impact of recent calamities and of unrecorded migration. The population base of the census of 1961 was adjusted in accordance with this model. The local mortality age pattern was used in projecting the population by sex and age groups to the date at which the census was originally due to be taken in 1971, and to the date when it was actually taken in March 1974. The post-1970 calamities and their effect on mortality were ignored. The aggregate estimate of population of 72.9 million in March 1974 is slightly in excess of the census count (by about two per cent) reported provisionally as 71.3 million. The excess in our estimate could be accounted for by the losses due to cyclone and military action.     

Estimation and Classification of BOLD Responses Over Multiple Trials

In this article, we model functional magnetic resonance imaging (fMRI) data for event-related experiment data using a fourth degree spline to fit voxel specific blood oxygenation level-dependent (BOLD) responses. The data are preprocessed for removing long term temporal components such as drifts using wavelet approximations. The spatial dependence is incorporated in the data by the application of 3D Gaussian spatial filter. The methodology assigns an activation score to each trial based on the voxel specific characteristics of the response curve. The proposed procedure has a capability of being fully automated and it produces activation images based on overall scores assigned to each voxel. The methodology is illustrated on real data from an event-related design experiment of visually guided saccades (VGS).     

Hypothesis testing, power and sample size determination for between group comparisons in fMRI experiments

Modern methods for imaging the human brain, such as functional magnetic resonance imaging (fMRI) present a range of challenging statistical problems. In this paper, we first develop a large sample based test for between group comparisons and use it to determine the necessary sample size in order to obtain a target power via simulation under various alternatives for a given pre-specified significance level. Both testing and sample size calculations are particularly critical for neuroscientists who use these new techniques, since each subject is expensive to image.     

部件维修质量对航空安全的影响

目前，航空公司对于航空维修安全和质量的关注焦点是航线维修以及与之相关的各类工作。为减少维修差错、确保飞机持续适航，航空公司应大加对造成维修差错，构成安全隐患的各类原因，进行更深入的分析。其中，对飞机维修产业链的上游，部件维修质量应进行更科学、更规范化、更有效的管理。本文将以我公司几年来开展部件维修质量调查和部件维修单位质量审核发现的各类问题为主要来源，     

A320-双液压失效

A320机型可以在一个低高度上遭遇一系列的双液压失效，比如，绿液压系统液压油的泄漏会造成黄系统管路的失效。     

Effects of exercise training with weighted vests on bone turnover and isokinetic strength in postmenopausal women

The effects of 12 wk of exercise training using weighted vests on bone turnover and isokinetic strength were evaluated in postmenopausal women randomly assigned as exercisers (EX; n = 9) or controls (CON; n = 7). Training included 3 multimodal exercise sessions per wk wearing weighted vests. The vest load was progressively increased each wk to a maximum of 15% of body weight. Bone turnover was determined from resting levels of serum osteocalcin and NTx. Knee and ankle strength were measured at 60 degrees/s and 180 degrees/s using an isokinetic dynamometer. After 12 wk, NTx decreased by 14.5% (P 相似文献   

Undocumented migration to Venezuela

"In 1980 Venezuela took...steps to regularize the undocumented migrant population. While the number responding to the amnesty was small relative to expectations, the majority of illegals appeared to have regularized their status. For the first time it was possible to assess objectively the characteristics of the undocumented population. Moreover, the problem of illegal migrants seems to have been temporarily solved, a result of both the amnesty and the country's declining economic activity." Topics covered in the present article include the nationality, geographic distribution, sex and age distribution, educational status, and occupations of undocumented migrants.     

Assessment of Indoor Route-finding Technology for People with Visual Impairment

This study investigated navigation with route instructions generated by digital-map software and synthetic speech. Participants, either visually impaired or sighted wearing blind folds, successfully located rooms in an unfamiliar building. Users with visual impairment demonstrated better route-finding performance when the technology provided distance information in number of steps rather than walking time or number of feet.