Controlled release urea as a nitrogen source for spring wheat in Western Canada: yield, grain N content, and N use efficiency.

Controlled release nitrogen (N) fertilizers have been commonly used in horticultural applications such as turf grasses and container-grown woody perennials. Agrium, a major N manufacturer in North and South America, is developing a low-cost controlled release urea (CRU) product for use in field crops such as grain corn, canola, wheat, and other small grain cereals. From 1998 to 2000, 11 field trials were conducted across western Canada to determine if seed-placed CRU could maintain crop yields and increase grain N and N use efficiency when compared to the practice of side-banding of urea N fertilizer. CRU was designed to release timely and adequate, but not excessive, amounts of N to the crop. Crop uptake of N from seed-placed CRU was sufficient to provide yields similar to those of side-banded urea N. Grain N concentrations of the CRU treatments were higher, on average, than those from side-banded urea, resulting in 4.2% higher N use efficiency across the entire N application range from 25 to 100 kg ha(-1). Higher levels of removal of N in grain from CRU compared to side-banded urea can result in less residual N remaining in the soil, and limit the possibility of N losses due to denitrification and leaching.

The principle of laplace and scaling of ventricular wall stress and blood pressure in mammals and birds.

Maximum left ventricular wall stress is calculated at end-diastolic volume and systemic arterial diastolic blood pressure, according to a thick-walled model for the principle of Laplace. Stress is independent of body mass and averages 13.9 kPa (+/-2.3; 95% confidence interval) in 24 species of mammals weighing 0.025-4,000 kg and 15.5 kPa (+/-4.7) in 12 birds weighing 0.014-110 kg. Birds have higher arterial blood pressures and larger hearts than mammals. Systolic and diastolic arterial blood pressures increase with body mass according to M(0.05) in mammals, and heart mass increases according to M(1.06) in the same species, further supporting the principle. However, blood pressure in birds is independent of body mass, and heart mass scales isometrically. End-diastolic stress values, calculated according to Laplace, are about one-third of peak stresses recorded in isolated mammalian myocardial preparations.

Influence of environmental oxygen on development and hatching of aquatic eggs of the australian frog, Crinia georgiana.

The effect of oxygen partial pressure (Po(2)) on development and hatching was investigated in aquatic embryos of the myobatrachid frog, Crinia georgiana, in the field and in the laboratory. Eggs from 29 field nests experienced widely variable Po(2) but similar temperatures. Mean Po(2) in different nests ranged between 2.9 and 19.3 kPa (grand mean 12.9 kPa), and mean temperature ranged between 11.9 degrees and 16.8 degrees C (grand mean 13.7 degrees C). There was no detectable effect of Po(2) or temperature on development rate or hatching time in the field, except in one nest at 2.9 kPa where the embryos died, presumably in association with hypoxia. Laboratory eggs were incubated at 15 degrees C at a range of Po(2) between 2 and 25 kPa. Between 5 and 25 kPa, there was almost no effect of Po(2) on development rate to stage 26, but the embryos hatched progressively earlier-at earlier stages and lower gut-free body mass-at lower Po(2). At 2 kPa, development was severely delayed, growth of the embryo slowed, and morphological anomalies appeared. A high tolerance to low Po(2) may be an adaptation to embryonic development in the potentially hypoxic, aquatic environment.

Predictive validity of the BRASS index in screening patients with post-discharge problems. Blaylock Risk Assessment Screening Score.

RATIONALE: Discharge planning is a nursing intervention that aims to ensure continuity of care; it consists of several steps of which selecting patients in need of it is the first one. The Blaylock Risk Assessment Screening Score (BRASS) index is a risk screening instrument which can be used early after admission to identify those patients in need of discharge planning. AIM: To test the predictive validity of the BRASS index in screening patients with post-discharge problems. DESIGN: Prospective longitudinal design with prediction instrument measured at admission, and outcomes measured at discharge and 7 and 30 days after discharge. OUTCOME MEASURES: length of stay, discharge destination, status after discharge. INSTRUMENTS: BRASS index, Problems after discharge Questionnaire, Nottingham Health Profile, COOP/WONCA charts. RESEARCH METHOD: 503 elderly patients were screened at admission with the BRASS index. Length of stay and discharge destination were measured at discharge in these same patients. Outcomes after discharge were gathered only in patients who were discharged home and with length of stay of more than 3 days (n=226); outcomes were measured by postal questionnaires at day 7 and day 30 after discharge. RESULTS: patients identified by the BRASS index as high risk are frequently not discharged home and have a longer length of stay. The BRASS scores correlate significantly with the outcome scores after discharge: the higher the BRASS score, the higher the difficulty score after discharge on all domains. However, the sensitivity of the BRASS index is rather low. CONCLUSION: This study demonstrates that the BRASS index is a good predictor instrument for indicating patients who are not discharged home, that the BRASS scores correlate significantly with problems experienced after discharge and that it has high specificity to predict patients with problems after discharge. Clinical use, however, is limited due to the low sensitivity. The BRASS index is a promising case-finding instrument for discharge planning, but needs further development.

Enantiomeric resolution using the macrocyclic antibiotics rifamycin B and rifamycin SV as chiral selectors for capillary electrophoresis.

Rifamycin B and rifamycin SV belong to the class of macrocyclic antibiotics known as ansamycins. These macrocyclic antibiotics were used as chiral selectors in capillary electrophoresis to enantioselectively resolve a number of chiral compounds. They contain groups capable of providing the types of multiple interactions necessary to achieve chiral recognition between enantiomers. In fact, they appear to be complimentary in the types of compounds they can enantiomerically resolve. Rifamycin B is shown to be enantioselective towards positively charged compounds, while rifamycin SV was enantioselective towards negatively charged solutes. The choice of wavelength for detection significantly affects sensitivity. Monitoring one of the wavelengths which coincide with the absorption minima of the chiral selector enhances sensitivity. Resolution is enhanced by keeping the amount of analyte injected on column as low as possible and it is demonstrated that it is possible to detect as little as 0.1% of one enantiomer in the presence of the other enantiomer using indirect detection.

Comprehensive discharge planning: a hospital-home healthcare partnership.

Shorter hospital stays place new demands on the discharge planning process. A research study that evaluated discharge planning outcomes reveals a critical need for comprehensive discharge planning involving both hospital and home healthcare agencies.

Discharge planning predicting patients' needs.

The elderly are at higher risk for longer and more frequent lengths of hospital stay than other adults. Comprehensive discharge planning programs, including early identification of those at risk, can alter these statistics. Screening inventories to identify patients at risk have been available for many years, but they are not specific to the needs of the elderly. The Blaylock Risk Assessment Screen (BRASS) is administered on admission and identifies patients at risk for prolonged hospital stay and in need of discharge planning resources. The nurse can use the data BRASS provides to improve care outcomes while the patient is in the hospital and in the transition to home care. It shows promise for use as the first phase of a discharge planning program.