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1.
J W McIntyre  C S Houston 《CMAJ》1999,161(12):1543-1547
Edward Jenner''s first treatise in 1798 described how he used cowpox material to provide immunity to the related smallpox virus. He sent this treatise and some cowpox material to his classmate John Clinch in Trinity, Nfld., who gave the first smallpox vaccinations in North America. Dissemination of the new technique, despite violent criticism, was rapid throughout Europe and the United States. Within a few years of its discovery, vaccination was instrumental in controlling smallpox epidemics among aboriginal people at remote trading posts of the Hudson''s Bay Company. Arm-to-arm transfer at 8-day intervals was common through most of the 19th century. Vaccination and quarantine eliminated endemic smallpox throughout Canada by 1946. The last case, in Toronto in 1962, came from Brazil.  相似文献   

2.
ObjectivesTo compare the extent to which late 20th century patterns of mortality in London are predicted by contemporary patterns of poverty and by late 19th century patterns of poverty. To test the hypothesis that the pattern of mortality from causes known to be related to deprivation in early life can be better predicted by the distribution of poverty in the late 19th century than by that in the late 20th century.DesignData from Charles Booth''s survey of inner London in 1896 were digitised and matched to contemporary local government wards. Ward level indices of relative poverty were derived from Booth''s survey and the 1991 UK census of population. All deaths which took place within the surveyed area between 1991 and 1995 were identified and assigned to contemporary local government wards. Standardised mortality ratios for various causes of death were calculated for each ward for all ages, under age 65, and over age 65. Simple correlation and partial correlation analysis were used to estimate the contribution of the indices of poverty from 1896 and 1991 in predicting ward level mortality ratios in the early 1990s.SettingInner London.ResultsFor many causes of death in London, measures of deprivation made around 1896 and 1991 both contributed strongly to predicting the current spatial distribution. Contemporary mortality from diseases which are known to be related to deprivation in early life (stomach cancer, stroke, lung cancer) is predicted more strongly by the distribution of poverty in 1896 than that in 1991. In addition, all cause mortality among people aged over 65 was slightly more strongly related to the geography of poverty in the late 19th century than to its contemporary distribution.ConclusionsContemporary patterns of some diseases have their roots in the past. The fundamental relation between spatial patterns of social deprivation and spatial patterns of mortality is so robust that a century of change in inner London has failed to disrupt it.  相似文献   

3.
Since 1960, landings of Atlantic herring have been the greatest of any marine species in Canada, surpassing Atlantic cod and accounting for 24% of the total seafood harvested in Atlantic Canada. The Scotian Shelf‐Bay of Fundy herring fisheries (NAFO Division 4VWX) is among Canada''s oldest and drives this productivity, accounting for up to 75% of the total herring catch in some years. The stocks’ productivity and overall health have declined since 1965. Despite management measures to promote recovery implemented since 2003, biomass remains low and is declining. The factors that drive the productivity of 4VWX herring are primarily unresolved, likely impeding the effectiveness of management actions on this stock. We evaluated potential drivers of herring variability by analyzing 52 time‐series that describe the temporal and spatial evolution of the 4VWX herring population and the physical, ecological, and anthropogenic factors that could affect them using structural equation models. Variation in herring biomass was best accounted for by the exploitation rate''s negative effect and the geographic distribution of fishing and recruitment. Thermal phenology and temperature adversely and egg predation positively impacted the early life stage mortality rate and, ultimately, adult biomass. These findings are broadly relevant to fisheries management, but particularly for 4VWX herring, where the current management approach does not consider their early life stage dynamics or assess them within the ecosystem or climate change contexts.  相似文献   

4.

Background

Nutrient loadings from its catchment upon The Fleet, a highly valuable coastal lagoon in Southern England, were hindcast for the period AD 1866–2004, using a catchment model, export coefficients, and historical data on land use changes, livestock numbers, and human population. Agriculture was the main nutrient source throughout, other inputs representing minor contributions. Permanent pasture was historically the main land use, with temporary grassland and cereals increasing during the mid-20th century. Sheep, the main 19th century livestock, were replaced by cattle during the 1930s.

Results

Total nitrogen loadings rose from ca 41 t yr-1 during the late 19th century to 49–54 t yr-1 for the mid-20th, increasing to 98 t yr-1 by 1986. Current values are ca 77 t yr-1. Total phosphorus loads increased from ca 0.75 t yr-1 for the late 19th century to ca 1.6 t yr-1 for the mid-20th, reached ca 2.2 t yr-1 in 1986, and are now ca 1.5 t yr-1. Loadings rose most rapidly between 1946 and 1988, owing to increased use of inorganic fertilisers, and rising sheep and cattle numbers. Livestock were the main nutrient source throughout, but inputs from inorganic fertilisers increased after 1946, peaking in 1986. Sewage treatment works and other sources contribute little nitrogen, but ca 35% of total phosphorus. Abbotsbury Swannery, an ancient Mute Swan community, provides ca 0.5% of total nitrogen, and ca 5% of total phosphorus inputs.

Conclusion

The Fleet has been grossly overloaded with nitrogen since 1866, climaxing during the 1980s. Total phosphorus inputs lay below 'permissible' limits until the 1980s, exceeding them in inner, less tidal parts of the lagoon, during the 1940s. Loadings on Abbotsbury Bay exceeded 'permissible' limits by the 1860s, becoming 'dangerous' during the mid-20th century. Phosphorus stripping at point sources will not significantly reduce loadings to all parts of the lagoon. Installation of 5 m buffer strips throughout the catchment and shoreline will marginally affect nitrogen loadings, but will reduce phosphorus inputs to the West Fleet below 'permissible' limits. Only a combination of measures will significantly affect Abbotsbury Bay, where, without effluent diversion, loadings will remain beyond 'permissible'.  相似文献   

5.
Aim The species‐specific response of tree‐line species to climatic forcing is a crucial topic in modelling climate‐driven ecosystem dynamics. In northern Québec, Canada, black spruce (Picea mariana) is the dominant species at the tree line, but white spruce (Picea glauca) also occurs along the maritime coast of Hudson Bay, and is expanding along the coast and on lands that have recently emerged because of isostatic uplift. Here we outline the present distribution, structure, dynamics and recent spread of white spruce from the tree line up to its northernmost position in the shrub tundra along the Hudson Bay coast. We aimed to obtain a minimum date of the arrival of the species in the area and to evaluate its dynamics relative to recent climate changes. Location White spruce populations and individuals were sampled along a latitudinal transect from the tree line to the northernmost individual in the shrub tundra along the Hudson Bay coast and in the Nastapoka archipelago in northern Québec and Nunavut, Canada (56°06′–56°32′ N). Methods White spruce populations were mapped, and the position, dimension, growth form and origin (seed or layering) of every individual recorded. Tree‐ring analyses of living and dead trees allowed an estimation of the population structure, past recruitment, growth trends and growth rate of the species. A macrofossil analysis was performed of the organic horizon of the northernmost white spruce stands and individuals. Radiocarbon dates of white spruce remains and organic matter were obtained. The rate of isostatic uplift was assessed by radiocarbon dating of drifted wood fragments. Results The first recorded establishment of white spruce was almost synchronous at all sites and occurred around ad 1660. Spruce recruitment was rather continuous at the tree line, while it showed a gap in the northern shrub tundra during the first decades of the 19th century. A vigorous, recent establishment of seedlings was observed in the shrub tundra; only wind‐exposed, low krummholz (stunted individuals) did not show any sexual regeneration. A period of suppressed growth occurred from the 1810s to the 1850s in most sites. A growth increase was evident from the second half of the 19th century and peaked in the 1880s and the 20th century. A shift from stunted to tree growth form has occurred since the mid‐19th century. No sample associated with white spruce remains gave a date older than 300 14C years bp [calibrated age (cal.) ad 1430–1690]. Main conclusions White spruce probably arrived recently in the coastal tundra of Hudson Bay due to a delayed post‐glacial spread. The arrival of the species probably occurred during the Little Ice Age. The established individuals survived by layering during unfavourable periods, but acted as nuclei for sexual recruitment almost continuously, except in the northernmost and most exposed sites. Warmer periods were marked by strong seedling recruitment and a shift to tree growth form. Unlike white spruce, black spruce showed no evidence of an ongoing change in growth form and sexual recruitment. Ecological requirements and recent history of tree‐line species should be taken into account in order to understand the present dynamics of high‐latitude ecosystems.  相似文献   

6.
In this work, the evolution of demographic and health patterns in a Basque rural population from Spain is analysed, as they relate to progress in demographic and epidemiological transition. For this purpose, parochial record data on 13,298 births and 9,215 deaths, registered during the 19th and 20th centuries (1800-1990), were examined. The study area is a rural community called Lanciego, which is located at the southern end of the Rioja Alavesa area (Alava Province, Basque Country). In Lanciego, demographic transition began in the final decade of the 19th century, when a definite, irreversible trend began towards a reduction in mortality. The decrease in the birth rate came later than that in the death rate, and did not start until the 1930s. The post-transitional stage seemed to be reached in the 1970s, when the birth and death rates showed values below 20 per 1,000. Other characteristics observed for the post-transitional stage in Lanciego are: (i) very low rates of infant mortality achieved at the expense of effective control of exogenous mortality; (ii) the mortality curve by ages changes from a U-shape (typical of populations with a high infant mortality rate and low life expectancy at birth) to a J-shape more characteristic of modern societies where longevity and life expectancy are considerably higher; (iii) a certain level of over-mortality among women in the senior age group (>65); and (iv) a significant proportion of mortality in recent times (1970-90) resulting from cardiovascular diseases and malignant neoplasms (post-transition causes). This last point is in contrast with observations from the first four decades of the 20th century, when infectious diseases and respiratory ailments were determining factors in mortality among this population. The data provided by the study of the variation over time in demographic and health patterns indicate that reducing the risk of mortality is one of the most important preconditions for fertility decline.  相似文献   

7.
Study of the mortality rates for carcinoma of the lung in men in Ontario between 1931 and 1959 reveals a rise from 3.7 in the early 1930''s to 26.7 per 100,000 in the late 1950''s. Analysis of age-specific mortality rates in five-year cohorts (groups of men born within five-year periods) shows that (1) mortality rates in each cohort rise rapidly after the age of 40, ascending in the later years of life almost as a straight line; (2) each succeeding cohort experiences an appreciably higher mortality rate than the preceding one. Mortality rates in individual cohorts in Ontario are compared with those in England; the shape of the cohort curves, and the rate of the increase in mortality from cohort to cohort, are almost identical. However, the picture in Ontario appears to be lagging some 10 years behind. The mortality rates for men in Ontario born around the year 1890 are almost identical with those shown by men born in England around 1880. The rates for carcinoma of the lung will almost inevitably continue to rise in Ontario for at least the next 10 to 20 years.  相似文献   

8.
B Malchy  M W Enns  T K Young  B J Cox 《CMAJ》1997,156(8):1133-1138
OBJECTIVE: To compare and contrast the characteristics of suicides among aboriginal and nonaboriginal people in Manitoba. DESIGN: Retrospective review of all suicides, based on a confidential analysis of records held by the Office of the Chief Medical Examiner. SETTING: Manitoba between 1988 and 1994. OUTCOME MEASURES: Standardized suicide rates, age- and sex-specific suicide rates, blood alcohol level at time of death, psychiatric help-seeking behaviour before suicide and residence on a reserve. RESULTS: Age-standardized suicide rates were 31.8 and 13.6 per 100,000 population per year among aboriginal and nonaboriginal people, respectively. The mean age of aboriginal people who committed suicide was 27.0 (standard deviation [SD] 10.8) years, compared with a mean age of 44.6 (SD 18.8) years for nonaboriginal people who committed suicide (p < 0.001). Blood alcohol levels at the time of death were a mean of 28 (SD 23) mmol/L among aboriginal people and 12 (SD 20) mmol/L among nonaboriginal people (p < 0.0001). Before their death, 21.9% of nonaboriginal suicide victims had sought psychiatric care whereas among aboriginal suicide victims 6.6% had sought care (p < 0.0001). Although the suicide rate was higher among aboriginal people living on reserve than among those living off reserve (52.9 v. 31.3 per 100,000 per year), both of these rates were substantially higher than the overall rates among nonaboriginal people. There were no significant differences in mean age, sex, blood alcohol level and previous psychiatric care among aboriginal people who committed suicide living on and off reserve. CONCLUSIONS: There was a high rate of suicide among Manitoba''s aboriginal people between 1988 and 1994; this rate was comparable to earlier estimates of national suicide rates among aboriginal people. The reserve environment does not, by itself, account for the high suicide rate among Manitoba''s aboriginal people. Further study of help-seeking behaviour and the association between alcohol abuse and suicide, particularly among aboriginal peoples, is indicated.  相似文献   

9.
A questionnaire was sent to disabled people to ascertain what part their general practitioners played in their long term care. The average consultation rate was 4.40 per patient a year. Overall, it appeared that the patients were most concerned with the general practitioner''s attitude towards them and the general practitioner''s availability.  相似文献   

10.
Reports of the rapidly increasing proportion of persons aged 65 years and more in Canada and the resultant need for changes in the country''s health care system prompted experimental changes in the operation and training procedures at St. Mary''s of the Lake Hospital, Kingston, Ont. Aimed at better patient care and at better education of medical house staff in geriatrics and long-term care, the revised program is permeated with the philosophy of rehabilitation. It includes full-time staff, a geriatric outpatient clinic, a day hospital, a team approach to patient care (with regular team audits), problem-oriented medical records, a formal physical medicine section with a district inpatient unit, and an intensive inservice education program. After the first year of the program patient outcome had improved and more efficient use was being made of continuing care beds because of larger numbers of patinets being discharged home after shorter stays. This may be one avenue for deceleration of our country''s dismal rate of institutionalization.  相似文献   

11.
R E Gagnon  A J Macnab  F A Gagnon 《CMAJ》2000,162(1):37-40
BACKGROUND: Since 1987 research articles have been catalogued with the author''s affiliation address in the 40 databases of the Medical Literature Analysis and Retrieval System (MEDLARS) of the National Library of Medicine, Bethesda, Md. The present study was conducted to examine the Canadian entries in MEDLARS to interpret past and future trends and to combine the MEDLARS demographic data with data from other sources to rank Canadian research output of human studies both nationally and internationally. METHODS: The PubMed Web site of the National Library of Medicine was used to count medical articles archived in MEDLARS and published from Jan. 1, 1989, through Dec. 31, 1998. The articles attributed to Canadian authors were compared by country, province, city, medical school, hospital, article type, journal and medical specialty. RESULTS: During the study period Canadian authors contributed on average 3% (standard deviation [SD] 0.2%) of the worldwide MEDLARS content each year, which translated to a mean of 11,067 (SD 1037) articles per year; 49% were human studies, of which 13% were clinical or controlled trials, and 55% involved people aged 18 years or less. In total, 68% of the articles were by authors affiliated with Canadian medical schools; those affiliated with the University of Toronto accounted for the greatest number (8604), whereas authors affiliated with McGill University had the greatest rate of annual increase in the quantity published (8%). Over one-third (38%) of the articles appeared in Canadian journals. When counted by specialty, 17% of the articles were by authors with clinical specialties, 5% by those with surgical specialties and 3% by those with laboratory specialties. INTERPRETATION: The annual rate of increase in research output for Canada was more than 3 times higher than that seen world wide. Canada is now ranked seventh among countries contributing human studies to MEDLARS. The increase indicates that Canada''s medical schools are productive, competitive in making contributions to medical science and are supporting Canadian journals.  相似文献   

12.
J Kazimirski 《CMAJ》1996,155(4):451-456
Dr. Judith Kazimirski of Nova Scotia becomes the CMA''s 126th president during the association''s annual meeting in Sydney, NS, this month. She says her priority for the next year is to help the CMA play a lead role as the debate intensifies about the future of health and health care in Canada. "The time is right for a very public debate about what people want their system to be, what problems they''re having, and how reform is moving ahead," she says, "and physicians have a critical leadership role to play."  相似文献   

13.
In 1986 the rate of infectious syphilis (primary and secondary) in Los Angeles County began to rise from previously stable levels of about 23.5 per 100,000 to peak at 55.6 per 100,000 in 1987. The incidence of congenital syphilis increased from 205 cases in 1987 to 575 cases in 1989. The county''s Sexually Transmitted Disease Program instituted a disease-specific plan to address the epidemic. Factors considered in designing the program included the high morbidity and mortality associated with congenital infection, the existence of latent infection, self-limiting symptoms, and the availability of an inexpensive screening test and curative treatment. Policy changes implemented comprised expanded screening, expanded surveillance, increased contact tracing, and the initiation of condom promotion programs. To evaluate the relative effectiveness of Los Angeles County''s syphilis control efforts, the epidemic curve for infectious syphilis was compared with trends in other urban areas. Although the rate of infectious syphilis climbed a year earlier in Los Angeles than in other cities, it returned to baseline levels when other cities'' rates remained at epidemic levels.  相似文献   

14.
15.
Natural mortality of Atlantic sturgeon (Acipenser oxyrinchus) has been determined to be low (M = 0.07). Reported herein is the mortality by beach stranding of 11 Atlantic sturgeon in Scot's Bay, part of the inner Bay of Fundy in Nova Scotia, Canada on 22 June 2014. Genetic analyses, histological analysis and age determination were performed to determine origin, maturity stage and age of the stranded Atlantic sturgeon. Microsatellite and mitochondrial DNA analyses indicated that four of the Atlantic sturgeon (2 males and 2 females) were from the Saint John River, NB population, which was designated as threatened by the Committee on the Status of Endangered Wildlife in Canada. Seven Atlantic sturgeon (1 male, 5 females, 1 unknown) were from the Kennebec River, Maine population, that was listed as threatened under the Endangered Species Act in the U. S. Ageing of A. oxyrinchus Atlantic sturgeon by pectoral fin spine analysis determined that the mean age of the individuals from the Saint John River (x? = 24.25 years, SD = 5.0) and the Kennebec River (x? = 22.7 years, SD = 3.5) were not significantly different. This is the first report of a stranding event of Atlantic sturgeon, and describes a source of natural mortality affecting populations of concern in both Canada and the U. S.  相似文献   

16.
I focus on the crucial links between the discovery of nonhuman primates by Westerners, discussions on our place in nature, the chain of being, racism, and the history of primate comparative anatomy and of so‐called “anatomical human racial studies.” Strikingly, for more than a millennium humans knew more about the internal anatomy of a single monkey species than about that of their own bodies. This is because Galen used monkeys to infer human anatomy, in line with the human‐animal continuity implied by the Greek notion of scala naturae. With the rise of Christianity, nonhuman primates were increasingly seen in a negative way. A more positive view emerged in the 14th century when nonhuman primates were directly studied/seen by Europeans, culminating in Tyson's 1699 work showing that chimps share more gross anatomical similarities with humans than with monkeys. However, the discomfort caused by this human‐chimp similarity then led to a new idea of animal‐human discontinuity, now related not to anatomy but to “civilization”: between Europeans vs. non‐Europeans + other primates. Moreover, Linnaeus' Systema Naturae and the emergence of “anatomical racial studies” influenced by Camper's craniology then led to even more extreme ideas, such as the notion that Europeans were both mentally and morphologically “ideal.” Unfortunately the biased and often incorrect “results” of such studies, combined with ideas based on Darwin's “struggle for survival”, became crucial in propaganda that lead to the rise of eugenics in the end of the 19th/first half of 20th centuries and that culminated in Nazism. Since the 1950s there has been an emphasis on the continuity/unity between all human groups and other primates, in great part influenced by what happened during World War 2. Reviews such as this one are, therefore, particularly necessary to illuminate and guard against attitudes against “the Other” and racist ideologies that are re‐emerging in modern political discourse across the globe.  相似文献   

17.
We describe adverse pregnancy outcomes, including congenital anomalies, fetal, neonatal, and infant mortality among a Missouri population of low‐income, rural mothers who participated in two randomized smoking cessation trials. In the Baby BEEP (BB) trial, 695 rural women were recruited from 21 WIC clinics with 650 women's pregnancy outcomes known (93.5% retention rate). Following the BB trial, 298 women who had a live infant after November 2004 were recruited again into and completed the Baby Beep for Kids (BBK) trial. Simple statistics describing the population and perinatal and postneonatal mortality rates were calculated. Of the adverse pregnancy outcomes (n = 79), 29% were spontaneous abortions of less than 20 weeks' gestation, 23% were premature births, and 49% were identified birth defects. The perinatal mortality rate was 15.9 per 1000 births (BB study) compared with 8.6 per 1000 births (state of Missouri) and 8.5 per 1000 births (United States). The postneonatal infant mortality rate was 13.4 per 1000 live births (BBK) compared with 2.1 per 1000 live births (United States). The health disparity in this population of impoverished, rural, pregnant women who smoke, particularly in regard to perinatal and infant deaths, warrants attention. Birth Defects Research (Part A), 2012. © 2012 Wiley Periodicals, Inc.  相似文献   

18.
J. M. Bowman  J. Pollock 《CMAJ》1983,129(4):343-345
For two decades the perinatal mortality caused by erythroblastosis has been decreasing in Manitoba. The improved management of Rh-immunized pregnancies has lowered the death rate among affected infants from 10.8% to 3.4%, while the prevention of Rh immunization has reduced its incidence from 9.1 to 2.2 per 1000 total births. In its first 6 years and 8 months Manitoba''s antenatal prophylaxis program, in which immunoglobulin is administered to Rh-negative women at 28 weeks'' gestation, reduced the incidence of Rh immunization during pregnancy by 93%. In combination with post-abortion and postpartum prophylaxis the antenatal treatment has provided a protection rate of 98.6% among primigravidas at risk. Further improvements are expected.  相似文献   

19.
Lewis''s Woodpecker (Melanerpes lewis) has experienced population declines in both Canada and the United States and in 2010 was assigned a national listing of threatened in Canada. We conducted a two-year study (2004–2005) of this species at its northern range limit, the South Okanagan Valley in British Columbia, Canada. Our main objective was to determine whether the habitat features that influenced nest-site selection also predicted nest success, or whether other factors (e.g. cavity dimensions, clutch initiation date or time of season) were more important. Nest tree decay class, density of suitable cavities and total basal area of large trees were the best predictors of nest-site selection, but these factors were unrelated to nesting success. Estimates of demographic parameters (mean ± SE) included daily nest survival rate (0.988±0.003, years combined), nest success (0.52±0.08), clutch size (5.00±0.14 eggs), female fledglings per successful nest (1.31±0.11), and annual productivity (0.68±0.12 female fledglings per nest per year). Although higher nest survival was associated with both early and late initiated clutches, early-initiated clutches allowed birds to gain the highest annual productivity as early clutches were larger. Nests in deep cavities with small entrances experienced lower predation risk especially during the peak period of nest predation. We concluded that nest-site selection can be predicted by a number of easily measured habitat variables, whereas nest success depended on complicated ecological interactions among nest predators, breeding behaviors, and cavity features. Thus, habitat-based conservation strategies should also consider ecological factors that may not be well predicted by habitat.  相似文献   

20.
M OReilly 《CMAJ》1998,158(3):380-381
Canada''s lack of self-sufficiency in blood products has led to the opening of a blood-plasma collection centre in Thunder Bay, Ont.--the first of its type in Canada. In convincing donors to donate plasma, the new centre had to overcome some lingering public concern about the safety of the blood-collection system.  相似文献   

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