The attitude of students towards their secondary school subjects

Thesis (Ed.M.)--Boston University, 1948. This item was digitized by the Internet Archive

Early symptoms and sensations as predictors of lung cancer: a machine learning multivariate model.

The aim of this study was to identify a combination of early predictive symptoms/sensations attributable to primary lung cancer (LC). An interactive e-questionnaire comprised of pre-diagnostic descriptors of first symptoms/sensations was administered to patients referred for suspected LC. Respondents were included in the present analysis only if they later received a primary LC diagnosis or had no cancer; and inclusion of each descriptor required ≥4 observations. Fully-completed data from 506/670 individuals later diagnosed with primary LC (n = 311) or no cancer (n = 195) were modelled with orthogonal projections to latent structures (OPLS). After analysing 145/285 descriptors, meeting inclusion criteria, through randomised seven-fold cross-validation (six-fold training set: n = 433; test set: n = 73), 63 provided best LC prediction. The most-significant LC-positive descriptors included a cough that varied over the day, back pain/aches/discomfort, early satiety, appetite loss, and having less strength. Upon combining the descriptors with the background variables current smoking, a cold/flu or pneumonia within the past two years, female sex, older age, a history of COPD (positive LC-association); antibiotics within the past two years, and a history of pneumonia (negative LC-association); the resulting 70-variable model had accurate cross-validated test set performance: area under the ROC curve = 0.767 (descriptors only: 0.736/background predictors only: 0.652), sensitivity = 84.8% (73.9/76.1%, respectively), specificity = 55.6% (66.7/51.9%, respectively). In conclusion, accurate prediction of LC was found through 63 early symptoms/sensations and seven background factors. Further research and precision in this model may lead to a tool for referral and LC diagnostic decision-making

Frequency distribution of conception dates in a white-tailed deer herd

Conception dates of white-tailed deer, Odocoi/eus virginia1111s (Zinunennann, 1780) were estimated for the breeding periods of 1974 - 76 and 1984 using fall and winter- spring fetal data. Conception dates estimated from data collected in the fall were biased. This bias resulted in an earlier mean conception date than that based on information which included data from later breeding females. Mean breeding dates differed significantly between female age classes due to delayed conception in fawns which also resulted in a skewed frequency distribution of conception dates. The frequency distribution of conception dates was leptokurtotic, suggesting that the distribution is constrnincd in time by some factor(s). Conception date estimates did not differ by habitat type but were influenced significantly by period of data collection. Mean breeding date for deer on Lhe Savannah River Site, corrected for age class sampling bias, is 20 November± 27 days (adults plus fawns) and 13 November± 15 days (only adults)

Frequency distribution of conception dates in a white-tailed deer herd

Conception dates of white-tailed deer, Odocoi/eus virginia1111s (Zinunennann, 1780) were estimated for the breeding periods of 1974 - 76 and 1984 using fall and winter- spring fetal data. Conception dates estimated from data collected in the fall were biased. This bias resulted in an earlier mean conception date than that based on information which included data from later breeding females. Mean breeding dates differed significantly between female age classes due to delayed conception in fawns which also resulted in a skewed frequency distribution of conception dates. The frequency distribution of conception dates was leptokurtotic, suggesting that the distribution is constrnincd in time by some factor(s). Conception date estimates did not differ by habitat type but were influenced significantly by period of data collection. Mean breeding date for deer on Lhe Savannah River Site, corrected for age class sampling bias, is 20 November± 27 days (adults plus fawns) and 13 November± 15 days (only adults)

The cost-effectiveness of Cochlear implants in Swedish adults.

BackgroundResearch has shown unilateral cochlear implants (CIs) significantly improve clinical outcomes and quality of life in adults. However, only 13% of eligible Swedish adults currently use a unilateral CI. The objective was to estimate the cost-effectiveness of unilateral CIs compared to a hearing aid for Swedish adults with severe to profound hearing loss.MethodsA Markov model with a lifetime horizon and six-month cycle length was developed to estimate the benefits and costs of unilateral CIs from the Swedish health system perspective. A treatment pathway was developed through consultation with clinical experts to estimate resource use and costs. Unit costs were derived from the Swedish National Board of Health and Welfare and the Swedish Association of Local Authorities and Regions. Health outcomes were reported in terms of Quality Adjusted Life Years (QALYs).ResultsUnilateral CIs for Swedish adults with severe to profound hearing loss are likely to be deemed cost-effective when compared to a hearing aid (SEK 140,474 per QALY gained). The results were most sensitive to the age when patients are implanted with a CI and the proportion of patients eligible for CIs after triage.ConclusionsAn increase in the prevalence of Swedish adults with severe to profound hearing loss is expected as the population ages. Earlier implantation of unilateral CIs improves the cost-effectiveness among people eligible for CIs. Unilateral CIs are an efficacious and cost-effective option to improve hearing and quality of life in Swedish adults with severe to profound hearing loss

Toward Guidelines for Harvest Intensities and Regeneration Targets with Minimal Impact Upon Retained Genetic Diversity in Central Hardwood Tree Species

There is an urgent need for a coordinated and systematic approach to the in situ conservation of the genetic resources of commercially important forest tree species in the Central Hardwoods. Effective in situ management of genetic resources would benefit from clear guidelines for how many adult trees can be harvested with minimal impact on allelic diversity. We are constructing a computer model for this purpose, and present preliminary results based upon replicate harvests of a virtual forest stand consisting of 200 adult trees. Our model explores how much regeneration is needed so that there is no more than a 10 percent risk of retaining less than 90 percent of the original allelic diversity. In the absence of regeneration, up to 55 percent of the adult trees can be harvested without exceeding the 10 percent risk level. At higher harvest intensities, locally-derived regeneration is needed to replace the alleles removed from the adult population. When all 200 adult trees are harvested, the 10 percent risk level is not exceeded if there are at least 116 regenerants, provided that these are derived from pre-harvest random mating among the adults. In the presence of substantial pollen flow from a genetically differentiated outside pollen source (e.g., 10-20 percent pollen flow), the minimum amount of regeneration needed is reduced. This indicates that outside pollen can be more efficient, relative to pollen from within the stand, at replacing alleles lost from the adult population

Assessment of Fawn Breeding in a South Carolina Deer Herd

Annual variation in breeding success among female white-tailed deer (Odocoileus virginianus) fawns on the Savannah River Plant (1967 to 1985) was determined from direct counts of pregnancy in spring-collected fawn females and evidence of lactation and measurements of udder thickness in fall-harvested 1. 5-yearolds. Percent lactation in 1.5-year-old females collected during September and October gave the best estimate of fawn breeding in the previous year. The overall mean fawn breeding estimate from September and October was 41 % , and the yearly variation in fawn breeding was significant. An estimate of the average yearly contribution to recruitment was 43 fetuses per 100 fawn females

Assessment of Fawn Breeding in a South Carolina Deer Herd

Annual variation in breeding success among female white-tailed deer (Odocoileus virginianus) fawns on the Savannah River Plant (1967 to 1985) was determined from direct counts of pregnancy in spring-collected fawn females and evidence of lactation and measurements of udder thickness in fall-harvested 1. 5-yearolds. Percent lactation in 1.5-year-old females collected during September and October gave the best estimate of fawn breeding in the previous year. The overall mean fawn breeding estimate from September and October was 41 % , and the yearly variation in fawn breeding was significant. An estimate of the average yearly contribution to recruitment was 43 fetuses per 100 fawn females

Habitat and Bird Communities at Small Airports in the Midwestern USA

Despite a substantial amount of information available on bird and other wildlife strikes at large international airports, relatively few researchers have considered bird hazards at smaller general aviation (GA) airports and airfields. However, small airports often are located in rural areas, and the potential for wildlife strikes may be significant, especially because airworthiness standards related to bird strikes are much less stringent for GA aircraft compared to commercial aircraft. In this study, we conducted habitat assessments (onsite land-cover evaluations and Geographic Information System analyses) and seasonal bird surveys (walking transects) over a period of 1 year at 10 small airports in the state of Indiana, USA. Across all airports, the 3 most abundant habitat types were short (mowed) grass (mean = 40.2% of total airport area), soybean fields (10.3%), and corn fields (9.5%). At least 2 types of bird attractants (e.g., standing water, agricultural fields, woodlots) were present at each airport property, although most airports had 5 to 7 types. Seven species groups (American kestrel [Falco sparverius], blackbirds-starling, crows-ravens, mourning dove [Zenaida macroura], shorebirds, sparrows, and swallows) each were present at 9-10 of the airport properties during 1 or more seasons. The most numerous species group was blackbirds-starling, although the abundance of this and most other species groups varied widely across seasons and airports. Our results indicate that small airports in Indiana contain many bird attractants and harbor substantial numbers of birds hazardous to aviation. Management of wildlife hazards at small airports is especially challenging, given that many such airports have limited resources available for design and implementation of effective wildlife management programs. Future research should evaluate the suitability of alternative habitat types and agricultural crops that are cost-effective but compatible with effective management of wildlife hazards to aviation