Stability, Resonance and Lyapunov Inequalities for Periodic Conservative Systems

This paper is devoted to the study of Lyapunov type inequalities for periodic conservative systems. The main results are derived from a previous analysis which relates the best Lyapunov constants to some especial (constrained or unconstrained) minimization problems. We provide some new results on the existence and uniqueness of solutions of nonlinear resonant and periodic systems. Finally, we present some new conditions which guarantee the stable boundedness of linear periodic conservative systems.Comment: 19 page

Canada

Excerpt: The first Europeans to inhabit what is now Canada came from Norse countries about 1000 AD to spend at least two winters at L’Anse aux Meadows, on the northwestern tip of Newfoundland. No evidence remains of any Christian religious activity on the part of these occupants. During the age of exploration, Europeans from many nations came to Canada for various reasons, including trade, political expansion, and Christian missions to the First Nations peoples already resident in Canada. As a result of such mission work, and the replication or expansion of churches from the European countries of origin of Canadian immigrants, church-sponsored education was widespread by the time Canada gained nationhood in 1867

Functional Inequalities: New Perspectives and New Applications

This book is not meant to be another compendium of select inequalities, nor does it claim to contain the latest or the slickest ways of proving them. This project is rather an attempt at describing how most functional inequalities are not merely the byproduct of ingenious guess work by a few wizards among us, but are often manifestations of certain natural mathematical structures and physical phenomena. Our main goal here is to show how this point of view leads to "systematic" approaches for not just proving the most basic functional inequalities, but also for understanding and improving them, and for devising new ones - sometimes at will, and often on demand.Comment: 17 pages; contact Nassif Ghoussoub (nassif @ math.ubc.ca) for a pre-publication pdf cop

Factors associated with not seeking professional help or disclosing intent prior to suicide : A study of medical examiners' records in Nova Scotia

Individual-level data from clinical settings lack information on people who did not seek professional help prior to suicide. We used records of the Nova Scotia Medical Examiner Service (NSMES) to compare people who had contact with a health professional prior to suicide with those who did not.We linked data from the NSMES to routine administrative data of the province.The NSMES recorded 108 suicides in Nova Scotia from January 1, 2006, to December 31, 2006; there were 90 male and 18 female suicide deaths. Mean and median age at death were 44.73 (SD 13.33) and 44 years, respectively. Patients aged 40 to 49 years made up one-third of the cases (n = 35) and this was the decade of life with the highest number of suicides. This was also the group least likely to have suicidal intent recorded in the NSMES files (χ(2) = 3.86, df = 1, P = 0.05). Otherwise, there were no significant differences between people who sought help, or disclosed intent, prior to suicide and people who did not. The samples in all cases were predominately male and single.People aged 40 to 49 years were the age group with the highest absolute number of suicides, but were the least likely to have suicidal intent recorded in the NSMES files. This finding merits further investigation. Medical examiner or coroner data may provide additional information not obtained elsewhere for the surveillance of suicide

No. 62: Heading North: The Zimbabwean Diaspora in Canada

Studies of the Zimbabwean diaspora tend to focus on migrants in South Africa and the United Kingdom. This is the first major study of Zimbabwean migration to Canada. The report presents and discusses the findings of a SAMP survey conducted across Canada in 2010. It first discusses the recent history of migration from Zimbabwe to Canada and then provides a demographic and socio-economic profile of the Zimbabwean diaspora in Canada. The report also examines the linkages that Zimbabweans in Canada maintain with Zimbabwe, and the potential for return migration. According to the 2006 Canadian Census, there were 8,040 Zimbabweborn people in Canada, comprising 6,525 immigrants (permanent residents and naturalized citizens) and 1,515 non-permanent residents (students and temporary workers). Immediately after independence in Zimbabwe in 1980, there was an increase in migration to Canada. The numbers rose briefly again in the late 1980s and then remained relatively low and stable for most of the 1990s. In other words, although emigration from Zimbabwe increased in the 1990s as economic prospects deteriorated, only a small number moved to Canada. This changed dramatically after 2000. Between 2003 and 2009, at least 400 Zimbabweans per annum were granted permanent residence in Canada. The peak year was 2004, when 1,456 Zimbabweans became permanent residents. Prior to 2000, most Zimbabwean migrants to Canada entered in the economic immigration class. After 2002, refugees came to dominate the inflow. Ontario is by far the most popular destination for Zimbabweans. Between 1980 and 2009, for example, nearly 60% of all immigrants settled first in that province. Other significant populations of Zimbabweans are found in the provinces of Alberta (13% of the total), British Columbia (12%) and Quebec (10%). The Zimbabwean population in Canada generally settles in major urban centres: over 80% live in cities with populations of more than 350,000. Toronto is the most popular destination with 41% of all immigrants. Although immigration from Zimbabwe to Canada is dominated by refugees, the survey showed that most possessed good professional qualifications upon entry. For instance, at least 30% had a university degree before leaving Zimbabwe. However, 40% were asked to re-certify or re-train in Canada in order to work in a field for which they were already trained. This highlights the more general problem of recognition of qualifications that foreign-trained professionals face in Canada. After moving to Canada, 70% continued with their formal education. Immigrants to Canada frequently discover that their credentials are less desirable on the job market or they have to settle for significantly less skilled occupations than in their countries of origin. This certainly seems to be the case with Zimbabweans, with 35% of respondents noting that they are working in a job that does not make full use of their professional qualifications and experience. Once they have gained entry to Canada, many Zimbabweans acquire more secure status that enables them to stay permanently. Nearly 50% of the respondents indicated that they are now Canadian citizens, while 33% are landed immigrants (permanent residents). The survey presented the respondents with 15 quality-of-life indicators and asked them to consider which country they rated more highly on each indicator. On virtually all of the indicators, Canada was ranked better than Zimbabwe by a significant margin. These included medical services, personal or family safety, future of children, prospects for professional advancement, availability of employment and job security, and level of income. Zimbabwe ranked more highly than Canada on only one indicator: the quality of social life. Most of the respondents have a significant number of family members still in Zimbabwe: 68% have siblings, 59% have parents and 55% have grandparents in the country. A smaller number have children (16%) and spouses (5%) in Zimbabwe. Despite these family ties, just over half of the respondents (52%) said they had not visited Zimbabwe since moving to Canada. One in five respondents visit Zimbabwe at least once every 2-3 years and a further 27% at least once every 5–10 years. Among those who have visited Zimbabwe at least once since arriving in Canada, the main purpose was for family issues and events. While Zimbabweans in Canada are not frequent visitors to Zimbabwe, this does not mean that they do not maintain links there. For example, 29% have bank accounts, 24% own a house, 19% own land and 8% have investments in Zimbabwe. Two-thirds of the respondents remit money to Zimbabwe. The average annual amount sent is CAD2,703, similar to that sent by Zimbabweans in the United Kingdom. Nearly one-third send money to Zimbabwe at least once a month. A further 28% remit a few times a year. Over 60% of those remitting send money to close family members while another 20% send money to their extended family. Only 4% said they deposit funds into a bank account for their own future use. Formal channels such as money transfer agencies and banks are the main mechanism for sending money to Zimbabwe. Informal transfer channels are used by only 17%. Consumption dominates the use of remittances. Over 80% of respondents said that the recipients purchase food with the funds, while other significant uses of remittances include paying for medical expenses, school fees and meeting other household day-to-day expenses. Investment of remittances was not very common: in the previous year only 8% had sent remittances to start or run a business, 7% for savings and 4% to buy property in Zimbabwe. Diaspora engagement has the potential to address some of the challenges facing Zimbabwe, providing a potential avenue for Zimbabweans in Canada to contribute to the country’s reconstruction. More than half of the survey respondents (55%) agreed or strongly agreed with the statement that they have an important role to play in the development of Zimbabwe. Zimbabweans in Canada clearly maintain strong social, religious and cultural links with each other. There is a strong sense of community among Zimbabweans, especially those in smaller cities, and it is not uncommon to find a large Zimbabwean presence at family events such as birthday celebrations, weddings and funerals. Many also belong to organizations and attracting growing interest. For almost 15 years South Africa. The survey found that, given the opportunity, the Zimbabwean diaspora in Canada is primed to engage directly in development-related activities. At present, only a minority are involved with development organizations that have links and programmes in Zimbabwe, but there are high levels of interest in activities such as skills transfer through training, educational exchanges, working in Zimbabwe and providing distance teaching via the internet. Financial support would take the form of fundraising for projects in Zimbabwe, investment in business, sending remittances for development projects, and making charitable donations. Economic activities of interest include investment in infrastructure and import and export of goods between Canada and Zimbabwe. Studies among Zimbabweans in the diaspora elsewhere have shown that two-thirds of those based in the United Kingdom and South Africa are likely to return to Zimbabwe. What is the likelihood of return among Zimbabwean migrants in Canada? The survey respondents were almost equally divided, with 52% indicating that they have given some thought to return and at least 45% saying that they had given no or hardly any thought to the possibility. However, only 8% indicated that it was likely or very likely that they would return to Zimbabwe within two years. The likelihood of return rises to 20% within five years and to 49% at some point in the future. Clearly, Zimbabweans in Canada are worried about the state of Zimbabwe’s economy and political environment, and expect things to improve, which would set a platform for their return to the country. The survey suggests that there is unlikely to be a large-scale return movement of the Zimbabwean diaspora in the immediate future. Most Zimbabweans in Canada want to see positive signs of real economic and political change before they would seriously consider returning

Canadian targets

Monetary policy - Canada ; Canada ; Money supply - Canada

The acheulean handaxe : More like a bird's song than a beatles' tune?

© 2016 Wiley Periodicals, Inc. KV is supported by the Netherlands Organization for Scientific Research. MC is supported by the Canada Research Chairs Program, the Social Sciences and Humanities Research of Canada, the Canada Foundation for Innovation, the British Columbia Knowledge Development Fund, and Simon Fraser UniversityPeer reviewedPublisher PD