Profile of Canadian physicians: results of the 1990 Physician Resource Questionnaire.

OBJECTIVE: To determine the supply, mix and distribution of physicians in Canada and to compare data with those of the 1982 and 1986 physician surveys. DESIGN: National census mail survey. SETTING: Canada. PARTICIPANTS: All physicians licensed to practise medicine in Canada, excluding interns and residents. A total of 52,422 questionnaires were mailed, of which 771 were ineligible. There were 38,313 valid responses (response rate 74.2%). MAIN OUTCOME MEASURES: Activity status, workload, specialty certification, practice setting and demographic profiles. MAIN RESULTS: A total of 88.7% of the respondents were active physicians; 19.4% were women, compared with 16.8% in 1986. Physicians reported working on average 4.1 fewer hours per week in total activities than in 1986 and 5.7 fewer hours per week than in 1982. As was found in 1982, about 50% of active physicians were certified specialists; 30% of specialists and 21% of general/family practitioners were 55 years of age or more. Approximately 11% of active physicians were in rural practice, as was reported in 1986. Similar proportions of foreign graduates and Canadian graduates were located in rural areas (10.9% and 11.4% respectively). CONCLUSIONS: Factors such as aging and retirement will affect specific specialty groups (e.g., general surgery and obstetrics/gynecology) in the near future. Specialty groups must address the issue of the future supply of physicians and the demand for their services when developing targeted needs within their specialties. The increasing proportion of women in medicine is changing the specialty mix and practice profiles of physicians as a whole. The issues associated with the recruitment and retention of physicians in rural areas remain complex.     

Devolving authority for health care in Canada's provinces: 2. Backgrounds,resources and activities of board members

OBJECTIVE: To obtain information from the members of the boards of devolved health care authorities and evaluate their orientations in meeting the expectations of provincial governments, local providers and community members. DESIGN: Mail survey, conducted in cooperation with the devolved authorities, in the summer of 1995. SETTING: Three provinces (Alberta, Saskatchewan and Prince Edward Island) with established boards and 2 (British Columbia and Nova Scotia) with immature boards. PARTICIPANTS: All 791 members of boards of devolved authorities in the 5 provinces, of whom 514 (65%) responded. OUTCOME MEASURES: Sociodemographic background, training, experience and activities of board members as well as their use of information. RESULTS: There were systematic differences between established and immature boards in regard to training, information use and actual and desired activities. Members spent 35 hours per month, on average, on work for their board. Members were largely middle-aged, well educated and well off. Only 36% were employed full time. Nine out of 10 had previous experience on boards, more often in health care than in social services. They were least pleased with their training in setting priorities and assessing health care needs and most pleased with their training in participating effectively in meetings and understanding their roles and responsibilities. The information for decision-making most available to them was information on service costs (68% said it was available "most of the time" or "always") and utilization (64%); the least available information was that on key informants'' opinions (47%), service benefits (37%) and citizens'' preferences (28%). Board activity was dominated by setting priorities and assessing needs, secondarily occupied with ensuring the effectiveness and efficiency of services and allocating funds, and least concerned with delivering services and raising revenue. The match between activities desired by members and actual activities was significantly poorer for members of immature boards than for those of established boards. CONCLUSIONS: The responses concerning these structural variables suggest that board members are most likely to meet the expectations of provincial governments. Fewer appear well equipped to accommodate the views of their providers and even fewer to incorporate the perspectives of their community.     

Particle size,resource concentration,and the distribution of net-spinning caddisflies

Summary The dimensions of net meshes constructed by hydropsychid Trichoptera vary both within and between species. Despite these catchnet differences, the diets of most Hydropsychidae studied in Utah streams were statistically indistinguishable. There was no relationship between the size of available resources and catchnet construction among species assemblages inhabiting 10 different localities. A particle-size model of caddis communities, suggesting that taxa feed selectively on particle sizes corresponding to the dimension of catchnet meshes, is not supported by these data.Diatom concentration increased regularly with downstream passage in two different drainages. The identity and number of coexisting hydropsychid species and the size of their catchnets were strongly correlated with diatom concentration. Taxa with large catchnet mesh were the only residents at sites where diatom concentration was very low; as resource concentration increased downstream, species with successively smaller mesh joined the coexisting guild. Together, the broad dietary similarities and distributional pattern from Utah streams suggest that resource concentration, rather than particle size, is the basis of community organization among the hydropsychid Trichoptera.     

Weekly work hours and clinical activities of Canadian family physicians: results of the 1997/98 National Family Physician Survey of the College of Family Physicians of Canada

BackgroundHealth systems planning is a challenging task, exacerbated by a lack of detailed information on the role played by family physicians, as indicated by practice variations across regions and demographic characteristics. Outcome measures used in past studies of family physician practice patterns were not uniform. Furthermore, past research has generally been limited to narrowly defined geographic regions. A national study of family physician practice patterns was undertaken to allow regional-level comparisons of clinical workload and range of medical services offered.MethodsThe 1997/98 National Family Physician Survey was mailed to a sample of 5198 Canadian family physicians and general practitioners (FP/GPs); the overall response rate was 58.4% (3036 questionnaires returned, of which 3004 were analyzable). Sampling strata were based on College of Family Physicians of Canada (CFPC) membership status and regions of Canada.ResultsClinical workload varied considerably across the demographic categories studied. Male physicians reported 8.9 more total weekly work hours than female physicians, but the mean number of medical and clinical services offered did not differ between the sexes. Solo practitioners reported 53.8 (95% confidence interval [CI] 52.7–55.0) total weekly work hours, whereas those practising in multidisciplinary clinics reported 45.0 (95% CI 43.2–46.8) hours. FP/GPs in the Atlantic and Prairie provinces reported 5.6 and 5.1 more weekly work hours, respectively, than the national average of 51.4 (95% CI 50.8–52.0) hours. Finally, FP/GPs who served inner-city populations reported 48.6 (95% CI 46.8–50.5) total weekly work hours, whereas those serving rural populations reported 57.0 (95% CI 54.7–59.2) hours. Mean weekly work hours were similar for all age cohorts less than 65 years. FP/GPs practising in less populated provinces and in rural areas reported the highest numbers of work hours, medical services offered and clinical procedures performed. InterpretationThese data suggest significant variations in FP/GP clinical workload in relation to key demographic variables. Physician resource planning in Canada is a challenging and inexact science. Past attempts have resulted in variable estimates of the ultimate need for physician services. There is a clear recognition that we need more information than simple head counts of physicians. We need to know, for example, what physicians do and how they work with other physicians, and we need to identify regional variations and differences in practice patterns.Past studies of family physician practice patterns have measured workload in terms of hours worked,^1,2,3 number of patient visits,^2,3 billings to health insurance plans^4,5 and range of clinical procedures performed.^5,6,7 These outcomes have been analyzed in relation to practice setting,^1,2,6,7 geographic physician density,^4,5 sex,^{1,2,3,4,5,6,7} age,^1,2,4,5,7 years in practice^3,6 and type of practice.^1,2,3,6,7Although past studies have proven useful in describing the significant relations that exist between physician workloads and demographic characteristics, they have not addressed the broader issue of access to family physicians'' services throughout Canada. By gathering uniform information from family doctors across the country, the College of Family Physicians of Canada (CFPC) National Family Physician Survey (NFPS) addresses this information gap. In this report we present the results of the 1997/98 NFPS, describing physician workload measures in relation to a comprehensive set of demographic variables.     

Myostimulatory neuropeptides in cockroaches: structures, distribution, pharmacological activities, and mimetic analogs

In this brief overview we give the historical background on the discovery of myostimulatory neuropeptides in cockroaches. Related peptides were later found in other insect groups as well. We summarize the current knowledge on primary structures, localization, physiological and pharmacological effects of the different cockroach neuropeptides, including kinins, sulfakinins, pyrokinins, tachykinin-related peptides, periviscerokinins, corazonin, and proctolin. In addition, we briefly comment on the development of mimetic pseudopeptide analogs in the context of their possible use in insect pest management.     

Extracellular enzymes in a small polyhumic lake: origin,distribution and activities

Seven extracellular enzymes were studied in a small polyhumic lake. Phosphatase, glucosidase and leucine-aminopeptidase were found to contribute strongest to the regeneration of nutrients and processing of polymeric organic substrates. Phosphatase activity varied between 10–800 nmol l^–1 h^–1 with highest activity in May–June. Glucosidase and leucine-aminopeptidase varied between 5–130 nmol l^–1 h^–1 with maxima in early and late summer. Phosphatase and leucine-aminopeptidase are stratified significantly in the water column. About 60% of leucine aminopeptidase could be attributed to bacterioplankton, whereas phosphatase were found to be 50–70% free dissolved in the water.     

ORENZA: a web resource for studying ORphan ENZyme activities

Background  

Despite the current availability of several hundreds of thousands of amino acid sequences, more than 36% of the enzyme activities (EC numbers) defined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB) are not associated with any amino acid sequence in major public databases. This wide gap separating knowledge of biochemical function and sequence information is found for nearly all classes of enzymes. Thus, there is an urgent need to explore these sequence-less EC numbers, in order to progressively close this gap.     

Relationship between resource selection, distribution, and abundance: a test with implications to theory and conservation

Much of applied and theoretical ecology is concerned with the interactions of habitat quality, animal distribution, and population abundance. We tested a technique that uses resource selection functions (RSF) to scale animal density to the relative probability of selecting a patch of habitat. Following an accurate survey of a reference block, the habitat-based density estimator can be used to predict population abundance for other areas with no or unreliable survey data. We parameterized and tested the technique using multiple years of radiotelemetry locations and survey data collected for woodland caribou across four landscape-level survey blocks. The habitat-based density estimator performed poorly. Predictions were no better than those of a simple area estimator and in some cases deviated from the observed by a factor of 10. We developed a simulation model to investigate factors that might influence prediction success. We experimentally manipulated population density, caribou distribution, ability of animals to track carrying capacity, and precision of the estimation equation. Our simulations suggested that interactions between population density, the size of the reference block, and the pattern of distribution can lead to large discrepancies between observed and predicted population numbers. Over- or undermatching patch carrying capacity and precision of the estimator can influence predictions, but the effect is much less extreme. Although there is some empirical and theoretical evidence to support a relationship between animal abundance and resource selection, our study suggests that a number of factors can seriously confound these relationships. Habitat-based density estimators might be effective where a stable, isolated population at equilibrium is used to generate predictions for areas with similar population parameters and ecological conditions.     

Photosynthesis and resource distribution through plant canopies

Plant canopies are characterized by dramatic gradients of light between canopy top and bottom, and interactions between light, temperature and water vapour deficits. This review summarizes current knowledge of potentials and limitations of acclimation of foliage photosynthetic capacity (A(max)) and light-harvesting efficiency to complex environmental gradients within the canopies. Acclimation of A(max) to high light availability involves accumulation of rate-limiting photosynthetic proteins per unit leaf area as the result of increases in leaf thickness in broad-leaved species and volume: total area ratio and mesophyll thickness in species with complex geometry of leaf cross-section. Enhancement of light-harvesting efficiency in low light occurs through increased chlorophyll production per unit dry mass, greater leaf area per unit dry mass investment in leaves and shoot architectural modifications that improve leaf exposure and reduce within-shoot shading. All these acclimation responses vary among species, resulting in species-specific use efficiencies of low and high light. In fast-growing canopies and in evergreen species, where foliage developed and acclimated to a certain light environment becomes shaded by newly developing foliage, leaf senescence, age-dependent changes in cell wall characteristics and limited foliage re-acclimation capacity can constrain adjustment of older leaves to modified light availabilities. The review further demonstrates that leaves in different canopy positions respond differently to dynamic fluctuations in light availability and to multiple environmental stresses. Foliage acclimated to high irradiance respond more plastically to rapid changes in leaf light environment, and is more resistant to co-occurring heat and water stress. However, in higher light, co-occurring stresses can more strongly curb the efficiency of foliage photosynthetic machinery through reductions in internal diffusion conductance to CO(2). This review demonstrates strong foliage potential for acclimation to within-canopy environmental gradients, but also highlights complex constraints on acclimation and foliage functioning resulting from light x foliage age interactions, multiple environmental stresses, dynamic light fluctuations and species-specific leaf and shoot structural constraints.     

The numbers and distribution of large mammals in Ruaha National Park,Tanzania*

Two aerial sample counts were carried out in Ruaha National Park, Tanzania, in the dry season of 1972 and the wet season of 1973. Population estimates of elephant, buffalo and other large mammals were made, and trend surface analysis was used to identify the basic gradients and contours of density, diversity and biomass within the Park. A cluster analysis, based on similarities between principal component scores, and validated by a multiple discriminant analysis, produced a classification of the Park into three Regions which differed significantly in densities, diversity and biomass. Ruaha Park carries year round a high density of elephants (1–7 km^-8). Seasonal movements into and out of the Park were not found, although movements within and between Regions could be detected.