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The purpose of this study was to evaluate the effectiveness of an invitation letter on cervical cancer screening participation among unscreened Manitoba women 30 to 69 years of age. A cluster randomized trial design was used in which unscreened women (n=31,452) were randomly assigned by the forward sortation area (FSA) of their postal code to an intervention group that was sent an invitation letter (n=17,068) or a control group that was not sent an invitation letter (n=14,384). In order to ensure access to screening, a Pap test clinic was held by a health centre in 20 of the 27 FSAs in the intervention group two to three weeks after the invitation letters were mailed. Six months after the letters were mailed, 1,010 women in the intervention group (5.92%) and 441 women in the control group (3.06%) had a Pap test. Women who were sent an invitation letter were significantly more likely to have had a Pap test in the next six months compared to women who were not sent an invitation letter (Odds Ratio (OR) = 2.05, 95% Confidence Interval (CI) 1.78-2.37, p<0.001). However, women who had a Pap test clinic in their FSA were not significantly more likely to have had a Pap test compared to women who did not have a Pap test clinic in their FSA (OR = 1.04, 95% CI 0.82-1.32, p=0.76). Using the Behavioural Model of Health Services Use as a theoretical framework, predisposing, enabling, and need factors that might influence screening participation were also included as covariables in multivariable logistic regression Generalized Estimating Equation (GEE) models. There was a significant main effect of age group (p<0.001), average household income (p=0.01), area of residence (p=0.01), residential mobility (p=0.05), and access (p=0.001). Interactions between the invitation letter and each significant variable were tested. The interaction between the invitation letter and age group remained significant (p=0.02); therefore, the effectiveness of the invitation letter was related to age.

Arizona is ranked third in the nation in fresh vegetable production, however, overfertilization and overirrigation have been common practices used to maintain adequate yields and crop quality. Concern for groundwater contamination, water availability and costs have made it necessary to increase water and nitrogen (N) use efficiency. The objectives of this research were: 1. optimize water and N inputs applied through a subsurface trickle irrigation system to leaf lettuce, spinach and collards. 2. evaluate water and N effects on midrib nitrate (NO₃-N) concentration as a tool for monitoring plant N status throughout the growing season. A field experiment was conducted during fall-winter 1992-93 at the University of Arizona Maricopa Agricultural Center, Maricopa, AZ. A factorial design with three target soil water potentials and four N levels was used to determine response surfaces for yield, net return, and water and N use efficiency. Tensiometers were used as an aid to schedule irrigations, and midrib NO₃-N concentrations at critical growth stages were used to monitor N status. Spinach and collard midrib N03-N concentrations showed a high response to N rates throughout the growing season. Leaf lettuce midrib NO₃-N was responsive to treatments at the beginning and end of its growing season. Some yield and efficiency parameters were significantly affected by the irrigation treatments with an effect generally negative. Nitrogen had tremendous influence on them, perhaps due to the wet seasonal conditions which may have promoted nitrate leaching and denitrification. For leaf lettuce, maximum fresh weight was estimated to be 60861 kg ha⁻¹ at -4.3 kPa soil water potential and 367 kg N ha⁻¹. Maximum net return was estimated to be $18,089 ha⁻¹ when average soil water potential was -6.0 kPa and applied N was 355 kg N ha⁻¹. Estimated maximum nitrogen use efficiency (NUE) was 0.8 at -10.3 kPa soil water potential, and 2 kg N ha⁻¹. It was not possible to determine a maximum value

Absorption and utilization of N by plants has been shown to be affected by the N form supplied and salinity. This study was conducted to determine the growth and N uptake of barley grown in modified Hoagland-Arnon nutrient solution containing different NH₄⁺-N / NO₃⁻-N ratios and various salinity levels in the growth chamber. The first experiment was conducted to study the N uptake rate at five different NH₄⁺-N/NO₃⁻-N ratios and three salinity levels (0, 6 and 12 bars). No ¹⁵N was applied in this experiment. The second experiment was conducted with the same objectives with modification in the salinity levels based upon the results of experiment 1. The salinity levels were 0 and 8 bars. The third experiment was similar to the second experiment except the duration of the study that was 45 days instead of 30 days. The NH₄⁺-N/NO₃⁻-N ratios were 0/100, 25/75, 50/50, 75/25 and 100/0. The total N concentration in all treatments was 100 ppm. Solutions were sampled after every 15 days during all experiments and analyzed for ammonium and nitrate concentration. For the short term ¹⁵N uptake study (experiments 2 and 3), either ammonium labelled ¹⁵N or nitrate labelled ¹⁵N was added to each NH₄⁺-N/NO₃⁻-N treatment for 6, 12, and 24 hours period on the last day of experiment 2 and 6, 12, and 18 hours period on the last day of experiment 3. Mixed N nutrition resulted in greater accumulation of whole plant-N than plants receiving only NO₃⁻ or NH₄⁺ as the source of N. Labelled nitrate recovery was highest in the 50% NH₄⁺ treatment. The same trend was evident from the solution sample analysis. In all the three experiments, plants produced significantly higher dry matter yields when grown with mixed N nutrition than with NH₄⁺ or NO₃⁻ alone. Total dry matter production, nitrogen uptake, root and shoot N contents, ¹⁵N content and water uptake decreased with increasing salinity levels in all the three experiments. The plants fed with ¹⁵NO₃⁻ source inhibited nitrate uptake more severally u

Dry and wet fine earth spectral measurements were made on the Ap soil surface horizons on the Maricopa Agricultural Center by using a Barnes Modular Multiband Radiometer. Three subsets were used in the analyses 552, 101 and 11. There were three soil series, Casa Grande, Shontik and Trix, four soil mapping units, and three texture classes identified on the farm. The wet soil condition reduced the amplitude of the spectral curves over the entire spectrum range (0.45 to 2.35 μm). The spectral curves were statistically related to the soil mapping units to determine if the soil mapping units and texture classes could be separated. The wet soil condition and the smaller sample size increased the correct classification percentages for soil mapping units and texture classes. LSD tests showed there were significant differences between these groups. Simple- and Multiple-linear regression analysis were used to relate some soil physical (sand, silt and clay contents and color components) and chemical (iron oxide, organic carbon and calcium carbonate contents) to soil spectral responses in the seven bands under dry and wet conditions. There were high correlations levels among the spectral bands showing an overlap of spectral information. Generally, the red (MMR3) and near-infrared (MMR4) bands had the highest correlations with the studied soil properties under dry and wet conditions. Usually, the wet soil condition resulted in higher correlations than that for the dry soil condition over the total spectrum range. The predictive equations for sand, silt and clay and iron oxide contents were satisfactory. For organic carbon and color components, the greatest success was achieved when variation in spectral response within individual samples are smaller than that between soil mapping unit group averages. There was a poor relation between calcium carbonate and spectral response. A comparison of multi-level remotely sensed data collected by SPOT, aircraft, and ground instruments showe