The Financial Circumstances of Elderly Canadians and the Implications for the Design of Canada’s Retirement Income System

It is well recognized that the incomes of the elderly are on average much lower than those of the non-elderly reflecting their limited participation in the labour market. But do the elderly have lower levels of economic well-being? Indeed, the financial circumstances of the elderly differ significantly from those of the non-elderly and these differences may compensate for lower income, increasing consumption potential relative to the non-elderly. In his paper, Malcolm Hamilton uses hitherto unexploited data from Statistics Canada’s Survey of Consumer Spending to examine the financial circumstances of the elderly and discusses the implications for the design of Canada’s retirement income system. Hamilton notes that there are five reasons why the unadjusted incomes of senior households should not be compared to those of younger households. Younger households often support children; devote a significant portion of their income to acquiring and financing consumer durables (cars, appliances, furniture) that seniors already possess; incur employment-related expenses (union dues, day-care, commuting costs, insurance); save part of their income for retirement; and pay higher taxes, including CPP and Employment Insurance (EI) premiums. Hamilton presents fascinating data for different types of households on uses of income by age group. He shows that the amount of income available for consumption, that is income after taxes, mortgage payments, savings, union dues, day-care and provision for children, is actually greater for fully retired senior couples than for prime age couples ($30,400 versus$28,600) even though average before-tax income of prime age couples is double that of senior couples. According to Hamilton, the data suggest that seniors need only around 50 per cent of their employment income to maintain their standard of living, not the 70 per cent that is commonly assumed in pension discussions. The implications of this finding for the design of the retirement system are many. Since government transfers replace 40 per cent of the income of the typical retiring Canadian, average Canadians will need little in the way of occupational pensions or retirement saving to live comfortably after 65. Most Canadians can retire in comfort if they eliminate debt and save a modest amount to supplement government pensions.Elderly, Canada, Pensions, Survey of Consumer Spending, Seniors, Spending, Savings

Narrow Linewidth 780 nm Distributed Feedback Lasers for Cold Atom Quantum Technology

Cold atom quantum technology systems have a wide range of potential applications which includes atomic clocks, rotational sensors, inertial sensors, quantum navigators, magnetometers and gravimeters. The UK Quantum Technology Hub in Sensors and Metrology has the aim of developing miniature cold atom systems using an approach similar to that pioneered by the chip scale atomic clock where microfabricated vacuum chambers have atomic transitions excited and probed by lasers. Whilst narrow linewidth Ti:Sa and external cavity diode lasers have been required for cooling and control, such lasers are too large, power hungry and expensive for future miniature cold atom systems. Here we demonstrate 1 mm long 780.24 nm GaAs/AlGaAs distributed feedback (DFB) lasers aimed at 87Rb cold atom systems operating at 20 ˚C with over 50 mW of power and side-mode suppression ratios of 46 dB using sidewall gratings and no regrowth. Rb spectroscopy is used to demonstrate linewidths below the required 6.07 MHz natural linewidth of the 87Rb D2 optical transition used for cooling. Initial packaged fibre-coupled devices demonstrate lifetimes greater than 200 hours. We also investigate the use of integrated semiconductor amplifiers (SOAs) and longer devices to further reduce the linewidths well below 1 MHz. A range of options to control the populations of electrons in the hyperfine split energy levels spaced by 3.417 GHz are examined. Two integrated lasers, integrated electro-absorption modulators (EAMs) and the direct modulation of a single DFB laser approaches are investigated and we will discuss which is best suited to integrated cold atom systems

On the distribution of queueing times for queues with two servers

Initially we consider first come first served queues with two or more servers wherein the intervals between the successive arrivals are independently and identically distributed. The customers1 service times are similarly distributed. The method is to define an embedded Markov chain on the moments just before each arrival and thence recurrences ^ which prelate the state of the system just before the (n+1; arrival to that which existed just before the nth. The problem is then specialized to that for two servers and these probability recurrences are used to develop a relationship between the bivariate Laplace transformations of the distribution functions which arise. The problem is reduced to the solution of a single integral equation for the Laplace transformation of the ergodic limiting distribution function by the definition of two compensation functions. These steps are analogous to the veil known probability "sweeping up" operations for one server queues. This integral equation is reduced to a functional equation for the case where the interarrival and service tine distributions are both composed of any integral numbers of exponential stages. This equation is solved in principle for all finite numbers of such stages, and in detail when the service time distribution has one or two stages and the interarrival time distribution any number. The results are checked against a known result for one case and a set of simulation results for another. The agreement is satisfactory. Of particular note are the curious loci of certain singularities. The Thesis also discusses a number of important intermediate results which suggest that the classical Miener-Kopf method for a unidimensional integral equation may generalize to a useful multidimensional result. We conclude with a section which outlines the proofs of a more general Theorem which explores this possibility

Soliton bound states in semiconductor disk laser

We report what we believe is the first demonstration of a temporal soliton bound state in semiconductor disk laser. The laser was passively mode-locked using a quantum dot based semiconductor saturable absorber mirror (QD-SESAM). Two mode-locking regimes were observed where the laser would emit single or closely spaced double pulses (soliton bound state regime) per cavity round-trip. The pulses in soliton bound state regime were spaced by discrete, fixed time duration. We use a system of delay differential equations to model the dynamics of our device

The social cognition of medical knowledge, with special reference to childhood epilepsy

This paper arose out of an engagement in medical communication courses at a Gulf university. It deploys a theoretical framework derived from a (critical) sociocognitive approach to discourse analysis in order to investigate three aspects of medical discourse relating to childhood epilepsy: the cognitive processes that are entailed in relating different types of medical knowledge to their communicative context; the types of medical knowledge that are constituted in the three different text types analysed; and the relationship between these different types of medical knowledge and the discursive features of each text type. The paper argues that there is a cognitive dimension to the human experience of understanding and talking about one specialized from of medical knowledge. It recommends that texts be studied in medical communication courses not just in terms of their discrete formal features but also critically, in terms of the knowledge which they produce, transmit and reproduce

Evidence for trans-generational medication in nature

Ecology Letters (2010) 13: 1485–1493Parasites pose a serious threat to host fitness, and natural selection should favour host traits that reduce infection or disease symptoms. Here, we provide the first evidence of trans-generational medication, in which animals actively use medicine to mitigate disease in their offspring. We studied monarch butterflies and their virulent protozoan parasites, and found that neither caterpillars nor adult butterflies could cure themselves of disease. Instead, adult butterflies preferentially laid their eggs on toxic plants that reduced parasite growth and disease in their offspring caterpillars. It has often been suggested that sick animals may use medication to cure themselves of disease, but evidence for the use of medication in nature has so far been scarce. Our results provide evidence that infected animals may indeed use medicine as a defence against parasites, and that such medication may target an individual’s offspring rather than the individual itself.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79381/1/j.1461-0248.2010.01537.x.pd

Scotopic electroretinogram in term infants born of mothers supplemented with docosahexaenoic acid during pregnancy

Purpose: to test the hypothesis that the supplementation of the diets of pregnant women with a fish oil rich in docosahexaenoic acid (DHA) enhances retinal development in their healthy term infants, as measured during the early postnatal period by the electroretinogram (ERG).Methods: one hundred pregnant women were randomized to receive either a fish oil (n = 50) or a placebo oleic acid dietary supplement (n = 50) from 15 weeks of pregnancy until delivery. Total fatty acids in red blood cells (RBCs) and plasma were measured in mothers at 15 and 28 weeks of pregnancy and at delivery and in their infants in umbilical cord blood. Infant retinal development was assessed within the first week of life with full-field ERGs that included a scotopic blue intensity series (n = 41) and a bright white flash (2.0 log cd-s/m2; n = 44).Results: infants born of mothers who received supplements did not differ at birth in weight, gestational age, or any other standard variable. Infant DHA status at birth, as measured from umbilical cord blood, did not differ significantly between maternal supplementation groups. ERG implicit times, amplitudes, and parameters of the stimulus–response function did not differ significantly between infants in the maternal supplemented and placebo groups. There was, however, a relationship between infant DHA status and maturity of the retina at birth, regardless of maternal supplementation group. A measure of retinal sensitivity (log σ) correlated significantly (P < 0.005) with DHA status (as a percentage of total fatty acid; TFA) in infant cord blood. Infants in the highest quartile for cord blood DHA had higher retinal sensitivity compared with infants in the lowest quartile. Infants in the highest quartile for plasma DHA, both as a percentage of TFA and concentration, were born at a significantly later gestational age than were infants in the lower quartiles.Conclusions: these findings demonstrate an association between the DHA status of term infants and retinal sensitivity, suggesting an essential role of this long-chain polyunsaturated fatty acid (LCPUFA) in the development and function of the retina. However, maternal DHA status was not significantly associated with infant retinal sensitivity and no direct effect of maternal supplementation was observed