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While ChatGPT has recently become very popular, AI has a long history and philosophy. This paper intends to explore the promises and pitfalls of the Generative Pre-trained Transformer (GPT) AI and potentially future technologies by adopting a speculative methodology. Speculative future narratives with a specific focus on educational contexts are provided in an attempt to identify emerging themes and discuss their implications for education in the 21st century. Affordances of (using) AI in Education (AIEd) and possible adverse effects are identified and discussed which emerge from the narratives. It is argued that now is the best of times to define human vs AI contribution to education because AI can accomplish more and more educational activities that used to be the prerogative of human educators. Therefore, it is imperative to rethink the respective roles of technology and human educators in education with a future-oriented mindset.

Key Points: Question: Do normotensive living kidney donors, compared with nondonors, have a higher risk of hypertension in the first 7 years following donation? Findings: In this 17-center prospective cohort study that included 924 living kidney donors and 396 nondonors, there were no significant between-group differences in the risk of hypertension and no significant between-group differences in mean blood pressure or the change in blood pressure during a median follow-up of 7.3 years. Meaning: After accounting for differences in baseline risk, living donors had a similar risk of hypertension as nondonors in the 7 years following donation and no significant difference in mean blood pressure. Importance: Recent guidelines call for better evidence on health outcomes after living kidney donation. Objective: To determine the risk of hypertension in normotensive adults who donated a kidney compared with nondonors of similar baseline health. Their rates of estimated glomerular filtration rate (eGFR) decline and risk of albuminuria were also compared. Design, Setting, and Participants: Prospective cohort study of 924 standard-criteria living kidney donors enrolled before surgery and a concurrent sample of 396 nondonors. Recruitment occurred from 2004 to 2014 from 17 transplant centers (12 in Canada and 5 in Australia); follow-up occurred until November 2021. Donors and nondonors had the same annual schedule of follow-up assessments. Inverse probability of treatment weighting on a propensity score was used to balance donors and nondonors on baseline characteristics. Exposure: Living kidney donation. Main Outcomes and Measures: Hypertension (systolic blood pressure [SBP] ≥140 mm Hg, diastolic blood pressure [DBP] ≥90 mm Hg, or antihypertensive medication), annualized change in eGFR (starting 12 months after donation/simulated donation date in nondonors), and albuminuria (albumin to creatinine ratio ≥3 mg/mmol [≥30 mg/g]). Results: Among the 924 donors, 66% were female; they had a mean age of 47 years and a mean eGFR of 100 mL/min/1.73 m2. Donors were more likely than nondonors to have a family history of kidney failure (464/922 [50%] vs 89/394 [23%], respectively). After statistical weighting, the sample of nondonors increased to 928 and baseline characteristics were similar between the 2 groups. During a median follow-up of 7.3 years (IQR, 6.0-9.0), in weighted analysis, hypertension occurred in 161 of 924 donors (17%) and 158 of 928 nondonors (17%) (weighted hazard ratio, 1.11 [95% CI, 0.75-1.66]). The longitudinal change in mean blood pressure was similar in donors and nondonors. After the initial drop in donors' eGFR after nephrectomy (mean, 32 mL/min/1.73 m2), donors had a 1.4-mL/min/1.73 m2 (95% CI, 1.2-1.5) per year lesser decline in eGFR than nondonors. However, more donors than nondonors had an eGFR between 30 and 60 mL/min/1.73 m2 at least once in follow-up (438/924 [47%] vs 49/928 [5%]). Albuminuria occurred in 132 of 905 donors (15%) and 95 of 904 nondonors (11%) (weighted hazard ratio, 1.46 [95% CI, 0.97-2.21]); the weighted between-group difference in the albumin to creatinine ratio was 1.02 (95% CI, 0.88-1.19). Conclusions and Relevance: In this cohort study of living kidney donors and nondonors with the same follow-up schedule, the risks of hypertension and albuminuria were not significantly different. After the initial drop in eGFR from nephrectomy, donors had a slower mean rate of eGFR decline than nondonors but were more likely to have an eGFR between 30 and 60 mL/min/1.73 m2 at least once in follow-up. Trial Registration: ClinicalTrials.gov Identifier: NCT00936078 This cohort study aims to determine the risk of hypertension in normotensive adults who donated a kidney compared with nondonors of similar baseline health. [ABSTRACT FROM AUTHOR]

The employment rate among persons with autism spectrum disorder has been noted as unacceptably low. Employment-support services are increasingly linked to the potential for favorable job outcomes, yet little is known about employment-support practices and the outcome of these interventions. This mixed-methods study examined employment-support resources for persons with autism spectrum disorder. An online survey was completed by 137 senior clinicians or administrators in employment-support programs in Canada. Additionally, 122 follow-up interviews were conducted with individuals with autism spectrum disorder (n = 71) and their parents/caregivers (n = 51). Findings indicate that the quality and beneficial impact of employment-support services for adults with autism spectrum disorder may be more favorably perceived by employment-support personnel than by individuals with autism spectrum disorder and their families. Furthermore, employment-support personnel were more disparaging about autism spectrum disorder vocational support capacity within their community, compared to their own programs. Individuals with autism spectrum disorder and their families seek services that support both accessing and retaining employment. Capacity-building in employment support for youth and adults with autism spectrum disorder is recommended, based on a reported insufficiency of, and a lack of evidence guiding, existing services. Program recommendations and an emerging model for integrated vocational support in autism spectrum disorder are offered.

Data collected between 1940 and 2009 from 11 weather stations across central Canada were used to explore temporal changes in mean winter daily minimum temperatures (WDMT) and the number of frost-free days (FFD) per winter. The main objective of the study was to estimate and predict temporal trends in FFD per winter, as well as to investigate the relationship between FFD and mean (WDMT) across a wide range of latitudes in central Canada. An exceedance probability model was developed to predict FFD per winter based on the definition of FFD per winter as an exceedance variable, the normal distribution function as an approximation of the frequency distribution of WDMT, and a relationship between the standard deviations and means of WDMT. The analyses of the mean WDMT time series revealed an overall average temperature increase of about 2°C over 100 years for the investigated stations. Further, the stations in central Canada have experienced an increase in FFD, with an average increase of 12 days in 100 years. The rate of increase in FFD, however, varied considerably among the 11 stations, from approximately 0.6 to 36 days per 100 years. Stations situated at northern latitudes exhibited relatively small increases, or no increases in FFD per winter, as compared to stations situated in southern areas. The FFD per winter were found to increase exponentially with steady increases in the mean WDMT values, matching the results obtained by solution of the developed exceedance model. Therefore, the exceedance model was shown to be an excellent tool for predicting FFD per winter, at least for the stations located widely across central Canada. [ABSTRACT FROM AUTHOR]

Background: Severe COVID-19 appears to disproportionately affect people who are immunocompromised, although Canadian data in this context are limited. We sought to determine factors associated with severe COVID-19 outcomes among recipients of organ transplants across Canada.Methods: We performed a multicentre, prospective cohort study of all recipients of solid organ transplants from 9 transplant programs in Canada who received a diagnosis of COVID-19 from March 2020 to November 2021. Data were analyzed to determine risk factors for oxygen requirement and other metrics of disease severity. We compared outcomes by organ transplant type and examined changes in outcomes over time. We performed a multivariable analysis to determine variables associated with need for supplemental oxygen.Results: A total of 509 patients with solid organ transplants had confirmed COVID-19 during the study period. Risk factors associated with needing (n = 190), compared with not needing (n = 319), supplemental oxygen included age (median 62.6 yr, interquartile range [IQR] 52.5-69.5 yr v. median 55.5 yr, IQR 47.5-66.5; p < 0.001) and number of comorbidities (median 3, IQR 2-3 v. median 2, IQR 1-3; p < 0.001), as well as parameters associated with immunosuppression. Recipients of lung transplants (n = 48) were more likely to have severe disease with a high mortality rate (n = 15, 31.3%) compared with recipients of other organ transplants, including kidney (n = 48, 14.8%), heart (n = 1, 4.4%), liver (n = 9, 11.4%) and kidney-pancreas (n = 3, 12.0%) transplants (p = 0.02). Protective factors against needing supplemental oxygen included having had a liver transplant and receiving azathioprine. Having had 2 doses of SARS-CoV-2 vaccine did not have an appreciable influence on oxygen requirement. Multivariable analysis showed that older age (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.02-1.07) and number of comorbidities (OR 1.63, 95% CI 1.30-2.04), among other factors, were associated with the need for supplemental oxygen. Over time, disease severity did not decline significantly.Interpretation: Despite therapeutic advances and vaccination of recipients of solid organ transplants, evidence of increased severity of COVID-19, in particular among those with lung transplants, supports ongoing public health measures to protect these at-risk people, and early use of COVID-19 therapies for recipients of solid organ transplants. [ABSTRACT FROM AUTHOR]

Describes a simulation model that examines the relationship of dropout behavior and re-entry flows in a local school system to changes in local socioeconomic factors, school-related conditions, and aspects of labor market participation. Assesses the policy implications for affecting these flows at the local board level. (Author/IRT)

Over the last decades, the extralinguistic benefits of bilingualism have been intensively debated. The current study was aimed at clarifying whether bilingualism speeds attentional disengagement. Reflecting faster disengagement, Mishra, Hilchey, Singh, and Klein (2012) observed an earlier onset of inhibition of return (IOR) for high than for low-proficient bilinguals. In contrast, Hernandez, Costa, Fuentes, Vivas, and Sebastian-Galles (2010) failed to find any difference between bilinguals and monolinguals. We investigated the source of this discrepancy, while improving methodology by using a large sample composed of 100 Canadians, objective assessments of second language skills (Nelson-Denny Reading test), and controlling for nonverbal intelligence, age, sex, and video-gaming. Results were analyzed with self-report and objective measures of second language proficiency as well as dichotomous and continuous measures. Compared to less proficient bilinguals, highly proficient bilinguals tended to respond faster overall, hinting at an executive processing advantage. However, contrary to Mishra et al.'s findings, bilingual proficiency did not affect either the onset of IOR or magnitude of IOR. [ABSTRACT FROM AUTHOR]

In the last decade, Lake Erie, one of the great lakes bordering Canada and the USA has been under serious threat due to increased phosphorus levels originating from agricultural fields. Large scale watersheds contributing to Lake Erie from the USA side are being simulated using hydrological and water quality (H/WQ) models such as the Soil and Water Assessment Tool (SWAT) and the results from the model are being used by policy and decision makers to implement better management decisions to solve emerging phosphorus issues. On the Canadian side, modeling applications are limited to either small watersheds or one major watershed contributing to Lake Erie. To the best of our knowledge, no efforts have been made to model the entire contributing watersheds to Lake Erie from Canada. This study applied the SWAT model for Northern Lake Erie Basin (NLEB; entire contributing basin to Lake Erie). Various provincial, national and global inputs of weather, land use and soil at various resolutions was assessed to evaluate the effects of input data types on the simulation of hydrological processes and streamflows. Twelve scenarios were developed using the input combinations and selected scenarios were evaluated at selected locations along the Grand and Thames Rivers using model performance statistics, and graphical comparisons of time variable plots and flow duration curves (FDCs). In addition, various hydrological components such as surface runoff, water yield, and evapotranspiration were also evaluated. Global level coarse resolution weather and soil did not perform better compared to fine resolution national data. Interestingly, in the case of land use, global and national/provincial land use were close, however, fine resolution provincial data performed slightly better. This study found that interpolated weather data from Environment Canada climate station observations performed slightly better compared to the measured data and therefore could be a good choice to use for large-scale H/WQ modeling studies. [ABSTRACT FROM AUTHOR]

The nature of unpaid caregiving is changing significantly in response to the changing nature of families, increased average life expectancy, and the rise in elderly populations. In order to adapt to these challenges, there is an increased focus on the workplace as a source of support for caregiver-employees (CEs), or employees providing unpaid care to a family member or friend while also working in paid employment. As demonstrated by Ireson et al. (2016), a number of workplaces in Canada and abroad are currently showing leadership with respect to the provision of caregiver-friendly workplace policies (CFWPs). The purpose of this study was to explore what is currently being offered to caregiver-employees by Canadian and international workplaces, as well as how these strategies have been defined, developed, introduced, integrated and sustained within the workplace. For the purposes of this study, CEs are defined as individuals engaged in paid employment, while simultaneously serving as an unpaid elder-care provider. To achieve the aims of this paper, a qualitative comparative case study of 21 workplaces was conducted. Participants were recruited via strategies such as snowball sampling, cold-calling and social media blasts. These workplaces, which operate as exemplars in meeting the needs of caregiver-employees, are pivotal to understanding the process which takes place in the implementation and success of CFWPs across various sectors/industries. The results of this study will be used to inform the wide gap in our knowledge about CFWPs while providing the evidence needed to workplaces and other organizations to introduce CFWPs into their employment practices. [ABSTRACT FROM AUTHOR]

Background: The undermanagement of pain in older adults has been identified as a problem worldwide. Aims: The purpose of this research is to identify priority areas in education and research for future development with the aim of improving pain management in older persons. In addition, barriers to addressing these priorities are identified. Methods: This mixed methods study, based on a modified Delphi approach, included three distinct components: (1) a qualitative component using focus groups with key informants or experts in the field of pain management in older adults (n = 17), (2) a scoping review of the literature, and (3) a survey of ranked responses completed by the same key informants who attended the focus groups. Thematic analysis was used to identify the initial list of issues and descriptive statistics were used for ranking them. Results: A number of concerns related to both education and research were frequently endorsed by participants. For education, they identified the need for more content in both undergraduate and continuing education programs related to documenting about pain; assessing pain, and learning about the complexities of pain. Research priorities included the need to explore successful practice models; costs of untreated pain; effects of mobility on pain; and patient preferences for pain management. Key barriers to addressing these barriers included lack of staff time and resources and unfamiliarity with pain assessment tools. Conclusion: These findings highlight priority issues related to pain management in older adults from a nationwide perspective. [ABSTRACT FROM AUTHOR]

To review the literature on mentoring of nursing students in Canada. Mentorship in nursing has been in existence for a long time. Supportive, nurturing guidance by an experienced individual in the profession has been found to have many benefits both to the giver and the receiver. However, there is no uniformity in the length, model, delivery method and evaluation of mentorship programs' impact. The purpose of this scoping review is to appraise the available literature and synthesize knowledge on mentorship in nursing in Canada. Scoping Review The scoping review was guided by the methodological framework developed by Hilary Arksey & Lisa O'Malley and the findings are reported using PRISMA ScR guidelines. A systematic search of MEDLINE, CINAHL, EMBASE and ERIC databases was conducted to identify articles describing nursing mentorship in Canada. After the initial screening, a total of 125 articles were included for a full-text review. Of the 48 items included, 28 were research articles and 20 were other forms of literature. Forty-eight items were included for data extraction. The scoping review revealed several benefits of mentorship. While synthesizing the evidence, it was noted that the components of the mentorship programs, such as the length, models, mode of delivery and the impact, vary with every nursing field. Based on the results of the scoping review, it is recommended to consider the unique needs, strengths and challenges of the group for whom the mentorship is planned. One size may not fit all. [ABSTRACT FROM AUTHOR]

Introduction. Acute headache is among the commonest presenting complaints to emergency departments. While it is estimated that only 1-3% result from subarachnoid haemorrhage (SAH), because the disease carries such significant morbidity and mortality if missed, most clinicians have a low threshold for investigation. A recent prospective cohort study in Canada determined a number of high-risk clinical characteristics for SAH in patients with acute headache. We investigated the potential impact of incorporating the Canadian clinical decision rules on British practice. Methods. A retrospective case note review on all adult patients presenting to our emergency department with acute headache between August and October 2011 was conducted. The Canadian decision rules for SAH were applied retrospectively to the cases identified, and the sensitivity, specificity and negative predictive values calculated. The two-tailed McNemar test was used to evaluate differences between proportions of patients undergoing investigations using the clinical decision rules against current practice. Results. In all, 112 patients met the inclusion criteria in a 3-month period, of which 41 patients (36.6%) underwent unenhanced computed tomography and 4 (3.6%) were found to have SAH. Nine patients subsequently had a lumbar puncture and none demonstrated xanthochromia. None of the patients who were not fully investigated were readmitted to the regional neurosurgical centre within 6 months of discharge with missed SAH. Application of the Canadian clinical decision rules would have led to an investigation rate between 59% and 74%, compared to an actual rate of 37% (p < 0.05). Conclusion. The present study shows that application of the Canadian clinical decision rules for SAH would lead to more patients with acute headache being investigated than current British practice. However, much larger prospective studies are required to determine whether such clinical decision rules may identify patients at risk who would otherwise have been missed. [ABSTRACT FROM AUTHOR]

Investigating the effect of lipid hydrophobicity on the activity of amphiphilic neomycin B conjugates, six polycationic amphiphiles (PAs) were created. Four of the new compounds incorporated either palmitic or arachidic di-lipid lysine tails, while two had single fluorinated undecanoic acid tails. The basicity of half of the compounds was increased through the incorporation of six guanidine moieties, in order to assess the effect of base strength on antimicrobial activity. A panel of ten bacteria was used for the testing, with seven strains obtained from the American Type Culture Collection series and three clinical isolates from Canadian Intensive Care Units. When compared to previous results with hydrocarbon monolipids the PAs all compounds were found to have reduced activity, though the hemolytic activity of the compounds with fluorinated tails was sharply reduced, with only a moderate reduction in antimicrobial activity. [ABSTRACT FROM AUTHOR]

Climate change and rapid urbanization could possibly increase the vulnerability of the Great Lakes Basin, Canada, which is the largest surface freshwater system in the world. This study explores the joint impact of climate change and land-use changes on the hydrology of a rapidly urbanizing Credit River watershed which lets out into Lake Ontario 25 km southwest of downtown Toronto, Ontario (ON), Canada; we began by classifying the watershed into urban and rural sections. A non-parametric Mann–Kendall test and the Sen slope estimator served to detect and describe the annual-, seasonal-, and monthly-scale trends in the climate variables (temperature, precipitation, and evapotranspiration), as well as the streamflow characteristics (median annual streamflow, baseflow, Runoff Coefficients (RC), Flow Duration Curve (FDC), Center of Volume (COV), and Peak Over Threshold (POT)) since 1916 for four rural and urban sub-watersheds. The temperature, precipitation and evapotranspiration (1950–2019) showed significant increasing trends for different months and seasons. Furthermore, the results indicated that the median annual streamflow, 7-day annual minimum flow, and days above normal are increasing; meanwhile, the annual maximum streamflow is decreasing. A total of 230 datasets were tested for their trends; of these, 80% and 20% increasing and decreasing trends were obtained, respectively. Of the total, significant trends (<0.05%) of 32% and 2% increasing and decreasing, respectively, were observed. The results of the FDC analysis indicated a decline in the annual and winter 10:90 exceedance ratio over the years for the rural and urban sub-watershed gauges. The BFI results show that the BFI of the rural areas was, on average, 18% higher than that of the urban areas. In addition, the RC also showed the influence of land-use and population changes on the watershed hydrology, as the RC for the urban gauge area was 19.3% higher than that for the rural area gauge. However, the difference in the RC was the lowest (5.8%) in the summer. Overall, the findings from this study highlight the annual, seasonal, and monthly changes in the temperature, precipitation, evapotranspiration, and streamflow in the watershed under study. Based on the available monitored data, it was difficult to quantify the changes in the streamflow over the decade which were attributable to population growth and land-cover use and management changes due to municipal official planning in the watershed. [ABSTRACT FROM AUTHOR]

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Resilient modulus (MR) value of a subgrade soil is the primary property needed for pavement design and analysis. It is the elastic modulus based on the recoverable strain under repeated loads, and depends on several factors including soil properties, soil type, and state of stresses. This paper presents prediction equations developed using regression analysis for six AASHTO soil types (A-1-b, A-3, A-2-4, A-4, A-6, and A-7-6) for estimating MR. Data extracted from the Long-Term Pavement Performance Information Management System (LTPP IMS) database for 258 test specimens (approximately 3,870 MR values) collected in 19 states in New England and the nearby regions in the United States and two provinces in Canada were used in this study. A generalized constitutive model that captures the effect of both bulk stress and octahedral shear stress was used to predict the MR of subgrade soils by developing regression equations that relate the k coefficients to the soil physical properties. The prediction models developed were verified for four types of soils collected in the New England region by independent laboratory MR tests. It was observed that MR values from the prediction models compared well with the laboratory values for the majority of the soil types. [ABSTRACT FROM AUTHOR]

Background: Systemic inflammation is associated with various complications in chronic obstructive pulmonary disease including weight loss, cachexia, osteoporosis, cancer and cardiovascular diseases. Inhaled corticosteroids attenuate airway inflammation, reduce exacerbations, and improve mortality in chronic obstructive pulmonary disease. Whether inhaled corticosteroids by themselves or in combination with a long-acting β2-adrenoceptor agonist repress systemic inflammation in chronic obstructive pulmonary disease is unknown. The Advair Biomarkers in COPD (ABC) study will determine whether the effects of inhaled corticosteroids alone or in combination with a long-acting β2-adrenoceptor agonist reduce systemic inflammation and improve health status in patients with chronic obstructive pulmonary disease. Methods/Design: After a 4-week run-in phase during which patients with stable chronic obstructive pulmonary disease will receive inhaled fluticasone (500 micrograms twice daily), followed by a 4-week withdrawal phase during which all inhaled corticosteroids and long acting β2-adrenoceptor agonists will be discontinued, patients will be randomized to receive fluticasone (500 micrograms twice daily), fluticasone/salmeterol combination (500/50 micrograms twice daily), or placebo for four weeks. The study will recruit 250 patients across 11 centers in western Canada. Patients must be 40 years of age or older with at least 10 pack-year smoking history and have chronic obstructive pulmonary disease defined as forced expiratory volume in one second to vital capacity ratio of 0.70 or less and forced expiratory volume in one second that is 80% of predicted or less. Patients will be excluded if they have any known chronic systemic infections, inflammatory conditions, history of previous solid organ transplantation, myocardial infarction, or cerebrovascular accident within the past 3 months prior to study enrolment. The primary endpoint is serum C-reactive protein level. Secondary end-points include circulating inflammatory cytokines such as interleukin-6 and interleukin-8 as well as health-related quality of life and lung function. Discussion: If inhaled corticosteroids by themselves or in combination with a long-acting β2-adrenoceptor agonist could repress systemic inflammation, they might greatly improve clinical prognosis by reducing various complications in chronic obstructive pulmonary disease. [ABSTRACT FROM AUTHOR]

Background: Inuit women from Northern Quebec have been shown to consume inadequate quantities of vitamin A. This study was conducted to evaluate the prevalence of blood vitamin A deficiency in newborns from 3 distinct populations of the province of Quebec. Methods: 594 newborns were included in this study (375 Inuit newborns from northern Québec (Nunavik), 107 Caucasian and Native newborns from the Lower Northern Shore of the Saint-Lawrence River (LNS) and 112 newborns from Southern Quebec where clinical vitamin A deficiency is uncommon). Mothers were recruited at delivery and vitamin A (retinol) was analyzed from umbilical cord blood samples by reversed-phase high-pressure liquid chromatography. Results: Nunavik and LNS newborns had significantly lower mean vitamin A concentrations in cord blood compared to Southern Québec participants (15.7 µg/dL, 16.8 µg/dL and 20.4 µg/dL respectively). The differences observed were similar when adjusted for sex and birthweight. Results also showed that 8.5% of Nunavik newborns and 12.2% of INS newborns were below 10.0 µg/dL, a level thought to be indicative of blood vitamin A deficiency in neonates. Conclusion: These data suggest that a carefully planned vitamin A supplementation program during pregnancy in Nunavik and LNS might be indicated to promote healthy infant development. [ABSTRACT FROM AUTHOR]

Examines the efficiency of vegetated filter strips for phosphorus removal from cropland runoff in Ontario. Effect of vegetation within the flowpath on water infiltration and water turbulence; Phosphorus concentration of the artificial runoff used; Average phosphorus trapping efficiency of all vegetated filters.

The effects of reductions in Canadian tariffs on imports from thirty non-OPEC Third World countries are estimated using quarterly data for the period 1972–79. Estimates of total trade expansion, trade diversion and trade creation are obtained using linear and a log-linear specification. The results imply that the trade diversion effect is in general and for most commodity groups larger than the trade creation effect. [ABSTRACT FROM AUTHOR]

The article presents information on the North American Free Trade Agreement (NAFTA). NAFTA, which is the largest trade coalition in the world in economic population and product, has a major influence on the regional and global economy. It aims on improving market access which can be achieved by removing barriers to merchandise trade. It represents the process of North American economic integration which has incorporated the 1965 Auto Pact and the 1988 Free Trade Agreement between the United States and Canada.

In this article the author replies back to the comments made by J.R. Hough on author's article "Economies of Scale in School Operation: Evidence from Canada," which was published in the 1983 issue of the journal "Applied Economics." Hough has raised two issues of largely statistical nature. These are 1) the use of an average (AC) rather than a total (TC) cost curve as the correct statistical device for examining economies of scale, and 2) estimation problems arising from possible heteroscedasticity of the error term in the estimating relation. The author argues that in footnote 2, on page 326, he did raise the issue of whether estimating an AC rather than a TC function is statistically more justifiable. In this context, Hough reminds us that the deployment of an AC curve will impart bias to the estimated coefficients. This would indeed be the case if the initial hypothesised relationship, perhaps on the basis of economic theory, were a TC curve. However, exactly the same problem will arise if the hypothesised relation were an AC curve and we tried to estimate its coefficients through the use of a TC curve, obtained by multiplying both sides by size.

The present study reports the result of an attempt to investigate the existence of economies of scale in educational costs at the school level for a board of education in the province of Ontario. While no new grounds are broken on the methodological front, the study contributes importantly in at least two directions. First, the costs considered are those actually incurred by schools, disaggregated into a number of categories. This should help not only in determining if there are significant differences in the behaviour of different components of cost, but also in identifying the sources of possible savings. Secondly, separate calculations are presented for three consecutive years. Results here should indicate if there were any significant shifts over time in the cost structure.
The following section reviews briefly the existing Canadian studies. Section III describes the methodology and data. The results are presented and discussed in Section IV. Section V, the concluding section, summarizes the main findings of the study. [ABSTRACT FROM AUTHOR]

This paper presents an attempt to examine the applicability of the relative income hypothesis (RIH) in terms of its various specifications proposed by Duesenberry, Duesenberry, Eckstein and Fromm (DEF), Davis and the authors (MD). Using the time series data for 1951 through 1968 the analysis has been carried out for Canada, Finland, Guatemala, Honduras, India, Japan, Philippines, Sweden, United Kingdom and the United States. It is found that RIH provides a fairly good representation of the consumption behaviour of all the countries included in the study. All specifications, however, do not perform equally well. DEF and Davis functions score the maximum points; MD comes at par with DEF in case of Finland, Guatemala, and India. The original Duesenberry specification performs very poorly. This lends us to conclude that the process of habit formation is continuous contrary to what is implied by Duesenberry's original specification and that consumption is a better indicator of the standard of living than income is. Estimates of the long-run marginal propensities to consume are essentially the same as those computed from the permanent income hypothesis by Singh and Drost [1970]. This lends support to the view that the two hypotheses have essentially the same long-run implications. [ABSTRACT FROM AUTHOR]

The article reports on the first shipment of cellulosic ethanol processed from wheat straw by the Ottawa, Canada-based private biotechnology firm Isogen International Corp. It notes that cellulosic ethanol is obtained from cellulose and is chemically identical to ethanol which is obtained from sugarcane molasses or starch in corn. According to research results, cellulosic conversion technologies are at least a decade away from supplying a significant proportion of the world's liquid fuels.

Abstract: Dietary habits that expose populations to potential toxicants as well as protective agents simultaneously are a realistic scenario where a meaningful assessment of the interactions and net benefit or damage can be made. A group of Inuit from Salluit, Northern Canada are exposed to high levels of PCBs and selenium, both present in the Inuit traditional foods such as blubber from sea mammals and fatty fish. Blood samples were collected from 83 Inuit, 22–70years old. Blood selenium and PCB levels were determined previously and ranged from 227 to 2069µg/L and 1.7 to 143µg/L, respectively. DNA isolated from white blood cells were analyzed by modified 32P-postlabeling adductomics technology that detects a multitude of highly polar to lipophilic adducts. The levels of 8-oxodG adducts ranged from 470 to 7400 adducts/109 nucleotides. Other as yet unidentified polar adducts showed a 30 to 800-fold inter-individual variability. Adduct levels were negatively associated with PCB and selenium levels. The subjects were classified into high and low ratio groups, with respect to selenium/PCB. In the high ratio group, the coefficient of selenium is significantly negatively correlated with 8-oxodG (r =−0.38, p =0.014) and total adducts (r =−0.41, p =0.009) while there was no correlation within the low selenium/PCB group. This study suggests that increasing selenium has mitigating effect in reducing DNA adducts and therefore, possible negative effects of PCB were not seen. A protective effect of selenium is highlighted. [ABSTRACT FROM AUTHOR]

Lower chlorinated PCBs can damage DNA directly or via free radical mechanisms. In order to assess the DNA-damaging potential of PCBs in humans, blood samples were collected from Inuit population from Salluit, Northern Canada. Their diet comprises blubber from sea mammals and fatty fish, which accumulate non-biodegradable PCBs at varying levels. The 103 samples thus collected were categorized into low-, medium- and high-PCB exposure groups. A comprehensive 32P-postlabeling adductomics technology, which allows measure differences in DNA adduct profiles of polar and lipophilic adducts between control and exposure groups, was applied to these samples to assess the effect of PCB on DNA damage. The adduct patterns obtained were qualitatively similar to other human tissues studied previously. A range of highly polar to lipophilic subgroups of adducts were detected. The known oxidative lesion, 8-oxodG was predominant. While some individual adducts appear to accumulate with increasing PCB levels, a definitive association could not be made. A possible confounder effect of selenium is discussed. [Copyright &y& Elsevier]