5,999 research outputs found

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

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    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 (30,400versus30,400 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

    MECHANICAL DAMPING SYSTEM FOR STRUCTURES

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    A mechanical damping system for a structure is provided. The mechanical damping system comprises a tubular impact frame secured to the structure. A support frame is secured to the structure with the support frame spaced from the impact frame. An elongated member is provided having a first end and a second end. The first end is secured within the support frame and the second end is free from connection and extends into the impact frame. At least one impact mass is secured to the second end of the elongated member, the impact mass movable within and contactable with the impact frame

    The Protagoras: Judge ... Jury ... and Explication

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    The idea of a trial is a strong aspect of the structure of Socrates’s direct conversation with Protagoras in Plato’s Protagoras. Each character in the dialogue assumes a particular role within the trial, with Socrates not as accused but as questioner. This paper uses the trial concept as a means in which to get inside the Protagoras and pry open the differing aspects of its characters

    Further characterization of glycine-containing microcystins from the McMurdo Dry Valleys of Antarctica

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    Microcystins are hepatotoxic cyclic peptides produced by several cyanobacterial genera worldwide. In 2008, our research group identified eight new glycine-containing microcystin congeners in two hydro-terrestrial mat samples from the McMurdo Dry Valleys of Eastern Antarctica. During the present study, high-resolution mass spectrometry, amino acid analysis and micro-scale thiol derivatization were used to further elucidate their structures. The Antarctic microcystin congeners contained the rare substitution of the position-1 D-alanine for glycine, as well as the acetyl desmethyl modification of the position-5 Adda moiety (3S-amino-9S-methoxy-2S,6,8S-trimethyl-10-phenyldeca-4E,6E-dienoic acid). Amino acid analysis was used to determine the stereochemistry of several of the amino acids and conclusively demonstrated the presence of glycine in the microcystins. A recently developed thiol derivatization technique showed that each microcystin contained dehydrobutyrine in position-7 instead of the commonly observed N-methyl dehydroalanine

    Trypanosomes are monophyletic: evidence from genes for glyceraldehyde phosphate dehydrogenase and small subunit ribosomal RNA.

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    The genomes of Trypanosoma brucei, Trypanosoma cruzi and Leishmania major have been sequenced, but the phylogenetic relationships of these three protozoa remain uncertain. We have constructed trypanosomatid phylogenies based on genes for glycosomal glyceraldehyde phosphate dehydrogenase (gGAPDH) and small subunit ribosomal RNA (SSU rRNA). Trees based on gGAPDH nucleotide and amino acid sequences (51 taxa) robustly support monophyly of genus Trypanosoma, which is revealed to be a relatively late-evolving lineage of the family Trypanosomatidae. Other trypanosomatids, including genus Leishmania, branch paraphyletically at the base of the trypanosome clade. On the other hand, analysis of the SSU rRNA gene data produced equivocal results, as trees either robustly support or reject monophyly depending on the range of taxa included in the alignment. We conclude that the SSU rRNA gene is not a reliable marker for inferring deep level trypanosome phylogeny. The gGAPDH results support the hypothesis that trypanosomes evolved from an ancestral insect parasite, which adapted to a vertebrate/insect transmission cycle. This implies that the switch from terrestrial insect to aquatic leech vectors for fish and some amphibian trypanosomes was secondary. We conclude that the three sequenced pathogens, T. brucei, T. cruzi and L. major, are only distantly related and have distinct evolutionary histories

    Adaptive capabilities and fitness consequences associated with pollution exposure in fish

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    Many fish populations are exposed to harmful levels of chemical pollution and selection pressures associated with these exposures have led to the evolution of tolerance. Our understanding of the physiological basis for these adaptations is limited, but they are likely to include processes involved with the absorption, distribution, metabolism and/or excretion of the target chemical. Other potential adaptive mechanisms include enhancements in antioxidant responses, an increased capacity for DNA and/or tissue repair and alterations to the life cycle of fish that enable earlier reproduction. Analysis of single-nucleotide polymorphism frequencies has shown that tolerance to hydrocarbon pollutants in both marine and estuarine fish species involves alteration in the expression of the xenobiotic metabolism enzyme CYP1A. In this review, we present novel data showing also that variants of the CYP1A gene have been under selection in guppies living in Trinidadian rivers heavily polluted with crude oil. Potential costs associated with these adaptations could reduce fitness in unpolluted water conditions. Integrating knowledge of local adaptation to pollution is an important future consideration in conservation practices such as for successful restocking, and improving connectivity within river systems. This article is part of the themed issue ‘Human influences on evolution, and the ecological and societal consequences’

    Molecular identification of different trypanosome species and subspecies in tsetse flies of northern Nigeria

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    Background: Animal African Trypanosomiasis (AAT) is caused by several species of trypanosomes including Trypanosoma congolense, T. vivax, T. godfreyi, T. simiae and T. brucei. Two of the subspecies of T. brucei also cause Human African Trypanosomiasis. Although some of them can be mechanically transmitted by biting flies; these trypanosomes are all transmitted by tsetse flies which are the cyclical vectors of Trypanosoma congolense, T. godfreyi, T. simiae and T. brucei. We present here the first report assessing the prevalence of trypanosomes in tsetse flies in Nigeria using molecular tools. Methods: 488 tsetse flies of three species, Glossina palpalis palpalis, G. tachinoides and G. morsitans submorsitans were collected from Wuya, Niger State and Yankari National Park, Bauchi State in 2012. Trypanosomes were detected and identified using an ITS1 PCR assay on DNA purified from the ‘head plus proboscis’ (H + P) and abdomen (ABD) parts of each fly. Results: T. vivax and T. congolense Savannah were the major parasites detected. Trypanosomes prevalence was 7.1 % in G. p. palpalis, 11.9 % in G. tachinoides and 13.5 % in G. m. submorsitans. Prevalences of T. congolense Savannah ranged from 2.5 to 6.7 % and of T. vivax were approximately 4.5 %. Trypanosoma congolense Forest, T. godfreyi and T. simiae were also detected in the site of Yankari. The main biological and ecological determinants of trypanosome prevalence were the fly sex, with more trypanosomes found in females than males, and the site, with T. congolense subspp. being more abundant in Yankari than in Wuya. As expected, the trypanosome species diversity was higher in Yankari National Park than in the more agricultural site of Wuya where vertebrate host species diversity is lower. Conclusions: Our results show that T. congolense Savannah and T. vivax are the main species of parasite potentially causing AAT in the two study sites and that Yankari National Park is a potential reservoir of trypanosomes both in terms of parasite abundance and species diversity

    The White Dwarf in EM Cygni: Beyond The Veil

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    We present a spectral analysis of the FUSE spectra of EM Cygni, a Z Cam DN system. The FUSE spectrum, obtained in quiescence, consists of 4 individual exposures (orbits): two exposures, at orbital phases phi ~ 0.65 and phi ~ 0.90, have a lower flux; and two exposures, at orbital phases phi =0.15 and 0.45, have a relatively higher flux. The change of flux level as a function of the orbital phase is consistent with the stream material (flowing over and below the disk from the hot spot region to smaller radii) partially masking the white dwarf. We carry out a spectral analysis of the FUSE data, obtained at phase 0.45 (when the flux is maximual, using the codes TLUSTY and SYNSPEC. Using a single white dwarf spectral component, we obtain a white dwarf temperature of 40,000K, rotating at 100km/s. The white dwarf, or conceivably, the material overflowing the disk rim, shows suprasolar abundances of silicon, sulphur and possibly nitrogen. Using a white dwarf+disk composite model, we obtain that the white dwarf temperature could be even as high as 50,000K, contributing more than 90% of the FUV flux, and the disk contributing less than 10% must have a mass accretion rate reaching 1.E-10 Msun/yr.In both cases, however, we obtain that the white dwarf temperature is much higher than previously estimated.Comment: accepted for publication in ApJ, 3 Tables, 12 Figures (including color figures), 33 pages in present format (possibly 10 pages in ApJ format
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