Effect of fallow frequency on soil water conservation in the semi-arid region of Saskatchewan

Non-Peer ReviewedThe effects of fallow frequency on soil water conservation were quantified for a 40 yr (1967-2006) field experiment conducted on a medium textured Orthic Brown Chernozem (Aridic Haploboroll) in semiarid southwestern Saskatchewan, in which soil water contents were measured each year in early spring, shortly after harvest, and again just prior to freeze-up in the fall. The three treatments examined were continuous wheat (Triticum aestivum L.) (Cont W) and fallow-wheat (F-W), each receiving N and P fertilizer and Cont W receiving only P. On average, 36 % of the precipitation received during the fall and winter months for Cont W (N+P) was conserved in the soil. In the summer fallow system (F-W (N+P)) a greater proportion (42 %) of the precipitation was conserved during the first fall and winter. During the second overwinter period, only 6 % of the precipitation received was conserved in the F-W system compared to 44 % in the first overwinter period. Compared to the 36% of fall and wither precipitation conserved in Cont W (N+P), inadequate N fertility (Cont W (+P)) resulted in only 27 % of the precipitation being conserved during this period. We developed equations that will allow estimation of water conserved as a function of precipitation received between harvest and seeding for F-W and Cont W (N+P. Trends in grain yield were fairly closely correlated with growing season precipitation and potential evapotranspiration

The Value of the Atrial Pacing Test

The atrial pacing test was performed on 62 subjects - 10 fit medical students, 15 patients with proven coronary artery disease and 37 patients referred for the elucidation of equivocal chest pain. Forty-nine of those studied were also subjected to a supine bicycle exercise test. The atrial pacing test appeared superior in regard to success rate, reproducibility and safety. Some disadvantages of both tests, hitherto ignored, are discussed. The phenomenon of the long P-R interval occurring at medium pacing rates was seen more frequently in the normal subjects and in those patients without coronary artery disease, in contrast to previously published work

Gall Bladder Disease and the Heart

Fifty patients subjected to operation for gall bladder disease undertook cardiac stress tests before and two months after surgery. Fourteen showed evidence of preexisting coronary heart disease and this was unaltered by operation. Squeezing the gall bladder during surgery provoked arrhythmias in six out of ten patients with coronary heart disease and in two out of fourteen of those without demonstrable heart disease. Removal of a diseases gall bladder may decrease the arrhythmia potential, particularly in patients with associated coronary heart disease, but does not alter the angina threshold

Serum Lipid Abnormalities and Atrial Pacing Test

Estimations of serum lipids and lipoprotein patterns were made in 32 patients with an abnormal repsonse to an atrial pacing test, and compared with similar estimations in 32 patients giving a normal response to the atrial pacing test. The frequency of serum lipid abnormalities was not significantly different in the two groups. These results were compared with the reported nature and frequency of lipid and lipoprotein abnormalities in patients with angiographically proved coronary artery disease, and the implications of these results are discussed

Can we predict the time of seedling emergence of spring wheat?

Non-Peer Reviewe

Long-term response of spring wheat to N and P fertilization in southwestern Saskatchewan

Non-Peer Reviewe

The precision of axon targeting of mouse olfactory sensory neurons requires the BACE1 protease

The β-site amyloid precursor protein cleaving enzyme 1 (BACE1) is necessary to generate the Aβ peptide, which is implicated in Alzheimer's disease pathology. Studies show that the expression of BACE1 and its protease activity are tightly regulated, but the physiological function of BACE1 remains poorly understood. Recently, numerous axon guidance proteins were identified as potential substrates of BACE1. Here, we examined the consequences of loss of BACE1 function in a well-defined in vivo model system of axon guidance, mouse olfactory sensory neurons (OSNs). The BACE1 protein resides predominantly in proximal segment and the termini of OSN axons, and the expression of BACE1 inversely correlates with odor-evoked neural activity. The precision of targeting of OSN axons is disturbed in both BACE1 null and, surprisingly, in BACE1 heterozygous mice. We propose that BACE1 cleavage of axon guidance proteins is essential to maintain the connectivity of OSNs in vivo