Strengthening Concept Development through the Inquiry Method

The purpose of this study was (1) to review the literature on concepts and concept development through inquiry; (2) to present guidelines for inquiry within the classroom; (3) to develop classroom lessons about contemporary Soviet life using the concept of inquiry and thirty-five millimeter slides; (4) to summarize and to offer recommendations for the use of inquiry in the classroom

Cation composition of tall fescue as affected by potassium and magnesium fertilization, temperature, and soil moisture

Field experiments were initiated on established stands of tall fescue (Festuca arundinacea Schreb.) located on soils subject to flooding at Knoxville and Chapel Hill, Tennessee. Treatments were imposed to determine effects on K, Mg, Ca, and A1 concentrations in tall fescue forage. Fertilizer treatments consisted of 112 kg Mg/ha, 181 kg K/ha, or a combination of both applied as Epsom salts, potassium sulfate, Sul-Po-Mag, or Epsom salts + potassium sulfate. Concen trations of K, Mg, Ca, and A1 in tall fescue forage were related to fertilizer treatments and variations in mean monthly air tem perature at each location. Potassium fertilization often resulted in higher K concentrations in the forage, while Mg fertilization had little effect on plant Mg concentration. At Chapel Hill fertilization with Mg or K had little effect on plant Ca concentration, while at Knoxville, Ca results were somewhat inconsistent. Aluminum concentration of plants was usually unaffected by fertilizer treatments. Equivalent ratios of K/(Ca + Mg) were sometimes in creased by K fertilization. Plant K concentrations were associated with increasing mean air temperature up to 12 or 13° C, when K concentrations declined. Magnesium concentrations in tall fescue declined through late fall and early winter, and then either declined or remained at low levels through spring. Calcium concentrations in the forage were somewhat ivV erratic in relation to mean air temperature. Aluminum concentration of the forage dropped considerably when temperatures rose above 10° C. Equivalent ratios of K/(Ca + Mg) closely followed trends of K in plant tissue as associated with temperature. Squares of sod were removed from a soil fertility field experiment for a greenhouse study in Knoxville. Epsom salts had been applied in the field at the rate of 0, 84, and 168 kg Mg/ha/year for 5 years. Half of the squares of sod were placed in trays that allowed drainage of water. The other half were placed in trays lined with polyethylene to prevent drainage and to approximate flooded field conditions. Equal numbers of sod trays were placed inside and outside the greenhouse to vary the temperature regime. In only one instance was K concentration in tall fescue affected by soil moisture, and in no instance was it affected by level of Mg fertilization. Magnesium concentration in forage was sometimes affected by soil moisture and was often increased by the highest level of Mg fertilization. Calcium concentration was not affected by soil moisture, but was often highest at 0 kg Mg/ha, indicating possible Mg-Ca competition. Aluminum was unaffected and equivalent ratios of K/(Ca + Mg) were not consistently affected by either soil moisture or Mg fertilization. Potassium, Mg, and Ca concentrations in tall fescue were usually higher at warmer temperatures while A1 concentrations were higher at cooler temper atures. Ratios of K/(Ca + Mg) were mostly unchanged between temperature regimes.VI In general, fertilization with Mg fertilizers had little consistent effect on increasing tall fescue Mg concentrations, while K fertilizers increased plant K content and the potential for tetany. Fertilization had no effect on decreasing plant Al. Mean air temperatures appeared to have a considerable influence on cation composition of tall fescue, and along with K fertilization may cause the greatest changes in potential for tetany

THI APPLICATION TO INSURING AGAINST HEAT STRESS IN DAIRY COWS

Heat stress is associated with reduced milk production in dairy cows. Insurance instruments based on an index of ambient temperature and relative humidity measured at Macon, Georgia and Tallahassee, Florida are shown to reduce net revenue risk for a representative farm in south-central Georgia.Risk and Uncertainty,

The epidemiology of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional condition of the bowel that is diagnosed using clinical criteria. This paper discusses the nature of the diagnostic process for IBS and how this impacts epidemiological measurements. Depending on the diagnostic criteria employed, IBS affects around 11% of the population globally. Around 30% of people who experience the symptoms of IBS will consult physicians for their IBS symptoms. These people do not have significantly different abdominal symptoms to those who do not consult, but they do have greater levels of anxiety and lower quality of life. Internationally, there is a female predominance in the prevalence of IBS. There is 25% less IBS diagnosed in those over 50 years and there is no association with socioeconomic status. IBS aggregates within families and the genetic and sociological factors potentially underlying this are reviewed. Patients diagnosed with IBS are highly likely to have other functional disease and have more surgery than the general population. There is no evidence that IBS is associated with an increased mortality risk. The epidemiological evidence surrounding these aspects of the natural history is discussed

A validation study of the CirCom comorbidity score in an English cirrhosis population using the Clinical Practice Research Datalink

Purpose: The CirCom score has been developed from Danish data as a specific measure of comorbidity for cirrhosis to predict all-cause mortality. We compared its performance with the Charlson Comorbidity Index (CCI) in an English cirrhosis population. Patients and methods: We used comorbidity scores in a survival model to predict mortality in a cirrhosis cohort in the Clinical Practice Research Datalink. The discrimination of each score was compared by age, gender, socioeconomic status, cirrhosis etiology, cirrhosis stage, and year after cirrhosis diagnosis. We also measured their ability to predict liver-related versus non-liver-related death. Results: There was a small improvement in the C statistic from the model using the CirCom score (C=0.63) compared to the CCI (C=0.62), and there was an overall improvement in the net reclassification index of 1.5%. The improvement was more notable in younger patients, those with an alcohol etiology, and those with compensated cirrhosis. Both scores performed better (C statistic >0.7) for non-liver-related deaths than liver-related deaths (C statistic <0.6), as comorbidity was only weakly predictive of liver-related death. Conclusion: The CirCom score provided a small improvement in performance over the CCI in the prediction of all-cause and non-liver mortality, but not liver-related mortality. Therefore, it is important to include a measure of comorbidity in studies of cirrhosis survival, alongside a measure of cirrhosis severity

Coeliac disease: studies of its frequency and consequence

Background The development of serological tests for the diagnosis of coeliac disease, including tests for endomysial and tissue transglutaminase antibodies, has made population screening for coeliac disease a realistic possibility. Several serological screening studies from European countries have shown that as many as 1% of the general population may have undetected coeliac disease. The implications of this diagnosis are unclear since the only data on the morbidity and physiological characteristics associated with previously undetected disease come from small, selected, case series. Most adult screening studies in the general population have identified only small numbers (i.e. less than 20 cases) of previously undetected cases and have therefore been unable to examine these issues through lack of statistical power. Clinically diagnosed coeliac disease has traditionally been linked with a variety of adverse co-morbid conditions including osteoporosis, non-Hodgkin’s lymphoma and an increased mortality in general. These conditions are thought to be partly a consequence of the altered nutritional status associated with the malabsorption that occurs with villous atrophy of the small bowel in coeliac disease. Although some of the adverse effects of, for example, vitamin and calcium deficiencies in coeliac disease have previously been explored whether there may be potentially beneficial effects of mild malabsorption have not. There are two main aspects in this thesis. The first is to estimate the prevalence of undetected coeliac disease in England and explore the important physiologic correlates of this condition. The second is to examine the risk of fracture, vascular disease, malignancy and mortality in people with diagnosed coeliac disease compared to the general population. Objectives 1. To estimate the seroprevalence of undetected coeliac disease in England. 2. To explore the relationship between undetected coeliac disease and various socio-demographic characteristics and physiological measures. 3. To quantify the impact of diagnosed coeliac disease (compared to the general population) on the risk of: a. Fracture b. Vascular disease (hypertension, high cholesterol, atrial fibrillation, myocardial infarction and stroke) c. Malignancy and mortality Methods To examine objectives 1 and 2 I utilised the Cambridge General Practice Health Study. This study identified individuals aged 45-76 registered with 12 general practices and invited them to complete a health survey, have a bone density measurement and submit a blood sample between 1990 and 1995. Serum samples from 7550 participants were tested for antiendomysial antibody (EMA). Seroprevalence of undetected coeliac disease was defined by EMA positivity. Differences between EMA positive and negative participants of various physiological measures and reported characteristics were estimated using multivariate logistic and linear regression and adjusted for age, gender, social class and smoking behaviour. To examine objective 3 I performed a population based cohort study using the General Practice Research Database to quantify the risk of fracture, vascular disease, malignancy and mortality in people with coeliac disease compared to the general population. I identified 4732 people with coeliac disease and 23620 age and sex matched control subjects. I used Cox regression to estimate hazard ratios for fracture, myocardial infarction, stroke, malignancy and mortality, and conditional logistic regression to estimate the risk of diagnosed hypertension, hypercholesterolaemia and atrial fibrillation, in people with coeliac disease compared to the general population. Findings The studies show that undetected coeliac disease is likely to affect about 1% of the population of England aged 45-76, a figure similar to several other countries. Those affected more commonly reported “good or excellent health”, however they do have an increased risk of osteoporosis and mild anaemia. In contrast they have a favourable cardiovascular risk profile including lower serum cholesterol and blood pressure. In people with clinically diagnosed coeliac disease, compared to the general population, there were small increases in both the absolute and relative overall fracture incidence with a 2-fold increase in the risk of hip fracture. Adults with treated coeliac disease did have a favourable vascular disease risk factor profile but numbers having heart attacks or strokes were modest and rates of heart attack and stroke were not reduced. There were modest increases in the overall risks of malignancy and mortality in people with coeliac disease and most of this excess risk occurred in the first year of follow up after diagnosis, suggesting ascertainment bias. I found a marked reduction in the risk of breast and lung cancer in people with coeliac disease and the mechanism of this merits further attention as it may provide insight into the aetiology of these common malignancies. Conclusions I found that approximately 1% of general adult population of the UK has undetected coeliac disease. The findings suggest that although coeliac disease is associated with some adverse conditions; it may also have some beneficial health effects. Please note: This version does not include the copies of journal articles which were included in the original thesis, but just details of the articles

A comparison of the recording of comorbidity in primary and secondary care by using the Charlson Index to predict short-term and long-term survival in a routine linked data cohort

OBJECTIVE: Hospital admission records provide snapshots of clinical histories for a subset of the population admitted to hospital. In contrast, primary care records provide continuous clinical histories for complete populations, but might lack detail about inpatient stays. Therefore, combining primary and secondary care records should improve the ability of comorbidity scores to predict survival in population-based studies, and provide better adjustment for case-mix differences when assessing mortality outcomes. DESIGN: Cohort study. SETTING: English primary and secondary care 1 January 2005 to 1 January 2010. PARTICIPANTS: All patients 20 years and older registered to a primary care practice contributing to the linked Clinical Practice Research Datalink from England. OUTCOME: The performance of the Charlson index with mortality was compared when derived from either primary or secondary care data or both. This was assessed in relation to short-term and long-term survival, age, consultation rate, and specific acute and chronic diseases. RESULTS: 657,264 people were followed up from 1 January 2005. Although primary care recorded more comorbidity than secondary care, the resulting C statistics for the Charlson index remained similar: 0.86 and 0.87, respectively. Higher consultation rates and restricted age bands reduced the performance of the Charlson index, but the index's excellent performance persisted over longer follow-up; the C statistic was 0.87 over 1 year, and 0.85 over all 5 years of follow-up. The Charlson index derived from secondary care comorbidity had a greater effect than primary care comorbidity in reducing the association of upper gastrointestinal bleeding with mortality. However, they had a similar effect in reducing the association of diabetes with mortality. CONCLUSIONS: These findings support the use of the Charlson index from linked data and show that secondary care comorbidity coding performed at least as well as that derived from primary care in predicting survival

Attention-deficit/hyperactivity disorder: variation by socio-economic deprivation

Background: In England, there is a discrepancy between the prevalence of Attention-deficit/hyperactivity disorder (ADHD) ascertained from medical records and community surveys. There is also a lack of data on variation in recorded prevalence by deprivation and geographical region; information that is important for service development and commissioning. Methods: Cohort study using data from the Clinical Practice Research Datalink comprising 5,196 children and young people aged 3-17 years with ADHD and 490,016 without, in 2012. Results: In 2012, the recorded prevalence (95%CI) of ADHD was 1.06 (1.03-1.09) %. Prevalence in the most deprived areas was double that of the least deprived areas (prevalence rate ratio (PRR) 2.58 (2.36-2.83)), with a linear trend from least to most deprived areas across all regions in England. Conclusions: The low prevalence of ADHD in medical records may indicate considerable under-diagnosis. Higher rates in more disadvantaged areas indicates greater need for services in those areas

Comorbidities affect risk of nonvariceal upper gastrointestinal bleeding

Background & Aims The incidence of upper gastrointestinal bleeding (GIB) has not been reduced despite the decreasing incidence of peptic ulcers, strategies to eradicate Helicobacter pylori infection, and prophylaxis against ulceration from nonsteroidal anti-inflammatory drugs. Other factors might therefore be involved in the pathogenesis of GIB. Patients with GIB have increasing nongastrointestinal comorbidity, so we investigated whether comorbidity itself increased the risk of GIB. Methods We conducted a matched case-control study using linked primary and secondary care data collected in England from April 1, 1997 through August 31, 2010. Patients older than 15 years with nonvariceal GIB (n = 16,355) were matched to 5 controls by age, sex, year, and practice (n = 81,636). All available risk factors for GIB were extracted and modeled using conditional logistic regression. Adjusted associations with nongastrointestinal comorbidity, defined using the Charlson Index, were then tested and sequential population attributable fractions calculated. Results Comorbidity had a strong graded association with GIB; the adjusted odds ratio for a single comorbidity was 1.43 (95% confidence interval [CI]: 1.35–1.52) and for multiple or severe comorbidity was 2.26 (95% CI: 2.14%–2.38%). The additional population attributable fraction for comorbidity (19.8%; 95% CI: 18.4%–21.2%) was considerably larger than that for any other measured risk factor, including aspirin or nonsteroidal anti-inflammatory drug use (3.0% and 3.1%, respectively). Conclusions Nongastrointestinal comorbidity is an independent risk factor for GIB, and contributes to a greater proportion of patients with bleeding in the population than other recognized risk factors. These findings could help in the assessment of potential causes of GIB, and also explain why the incidence of GIB remains high in an aging population

Coeliac disease: studies of its frequency and consequence

Background The development of serological tests for the diagnosis of coeliac disease, including tests for endomysial and tissue transglutaminase antibodies, has made population screening for coeliac disease a realistic possibility. Several serological screening studies from European countries have shown that as many as 1% of the general population may have undetected coeliac disease. The implications of this diagnosis are unclear since the only data on the morbidity and physiological characteristics associated with previously undetected disease come from small, selected, case series. Most adult screening studies in the general population have identified only small numbers (i.e. less than 20 cases) of previously undetected cases and have therefore been unable to examine these issues through lack of statistical power. Clinically diagnosed coeliac disease has traditionally been linked with a variety of adverse co-morbid conditions including osteoporosis, non-Hodgkin’s lymphoma and an increased mortality in general. These conditions are thought to be partly a consequence of the altered nutritional status associated with the malabsorption that occurs with villous atrophy of the small bowel in coeliac disease. Although some of the adverse effects of, for example, vitamin and calcium deficiencies in coeliac disease have previously been explored whether there may be potentially beneficial effects of mild malabsorption have not. There are two main aspects in this thesis. The first is to estimate the prevalence of undetected coeliac disease in England and explore the important physiologic correlates of this condition. The second is to examine the risk of fracture, vascular disease, malignancy and mortality in people with diagnosed coeliac disease compared to the general population. Objectives 1. To estimate the seroprevalence of undetected coeliac disease in England. 2. To explore the relationship between undetected coeliac disease and various socio-demographic characteristics and physiological measures. 3. To quantify the impact of diagnosed coeliac disease (compared to the general population) on the risk of: a. Fracture b. Vascular disease (hypertension, high cholesterol, atrial fibrillation, myocardial infarction and stroke) c. Malignancy and mortality Methods To examine objectives 1 and 2 I utilised the Cambridge General Practice Health Study. This study identified individuals aged 45-76 registered with 12 general practices and invited them to complete a health survey, have a bone density measurement and submit a blood sample between 1990 and 1995. Serum samples from 7550 participants were tested for antiendomysial antibody (EMA). Seroprevalence of undetected coeliac disease was defined by EMA positivity. Differences between EMA positive and negative participants of various physiological measures and reported characteristics were estimated using multivariate logistic and linear regression and adjusted for age, gender, social class and smoking behaviour. To examine objective 3 I performed a population based cohort study using the General Practice Research Database to quantify the risk of fracture, vascular disease, malignancy and mortality in people with coeliac disease compared to the general population. I identified 4732 people with coeliac disease and 23620 age and sex matched control subjects. I used Cox regression to estimate hazard ratios for fracture, myocardial infarction, stroke, malignancy and mortality, and conditional logistic regression to estimate the risk of diagnosed hypertension, hypercholesterolaemia and atrial fibrillation, in people with coeliac disease compared to the general population. Findings The studies show that undetected coeliac disease is likely to affect about 1% of the population of England aged 45-76, a figure similar to several other countries. Those affected more commonly reported “good or excellent health”, however they do have an increased risk of osteoporosis and mild anaemia. In contrast they have a favourable cardiovascular risk profile including lower serum cholesterol and blood pressure. In people with clinically diagnosed coeliac disease, compared to the general population, there were small increases in both the absolute and relative overall fracture incidence with a 2-fold increase in the risk of hip fracture. Adults with treated coeliac disease did have a favourable vascular disease risk factor profile but numbers having heart attacks or strokes were modest and rates of heart attack and stroke were not reduced. There were modest increases in the overall risks of malignancy and mortality in people with coeliac disease and most of this excess risk occurred in the first year of follow up after diagnosis, suggesting ascertainment bias. I found a marked reduction in the risk of breast and lung cancer in people with coeliac disease and the mechanism of this merits further attention as it may provide insight into the aetiology of these common malignancies. Conclusions I found that approximately 1% of general adult population of the UK has undetected coeliac disease. The findings suggest that although coeliac disease is associated with some adverse conditions; it may also have some beneficial health effects. Please note: This version does not include the copies of journal articles which were included in the original thesis, but just details of the articles