Liu, C., Gan, Y. and Poppy, L. 2014. Evaluation of on-farm crop management decisions on canola productivity. Can. J. Plant Sci. 94: 131–139. This study determined key factors affecting canola productivity in western Canada and evaluated the differences among soil-climatic zones in canola crops responding to the key agronomic factors. A total of 68 canola farm fields were randomly selected in western Canada, and multiple correspondence analysis, coupled with multivariate predictive model with partial least squares projection and regressions, was used to analyze the data set. Canola produced in Alberta averaged 2500 kg ha−1, and was 23% greater than canola produced in southern Saskatchewan, 10% greater than canola produced in northern Saskatchewan, and 59% greater than canola produced in Manitoba. Canola produced on chem-fallow averaged 2557 kg ha−1, and was 17% greater than canola grown on cereal stubble, or 43% greater than canola grown on pea/lentil, corn stubble. Canola grown on canola stubble produced 54% of the seed yield as canola grown on cereal stubble, or 46% of the seed yield as canola grown on chem-fallow. Shallow and earlier seeding with narrow row spacing increased canola seed yields consistently. Canola receiving K fertilizer increased seed yield by an average of 25% compared with those receiving no K fertilizer. Straight combine resulted in 500 kg ha−1 or 24% more seed yield than conventional swath-combine method. Those key factors may serve as the first-hand information in the development of sound guidelines for less experienced canola producers in western Canada.

Dental pulp repair is a difficult clinical problem. In the present study, the authors aimed to mimic the extracellular matrix of dental pulp tissue structurally and compositionally. Nanofibrous silk fibroin (SF) scaffolds containing hydroxyapatite (HAp) nanoparticles were fabricated by using the freeze-drying approach. Rod-shaped HAp was successfully embedded in the composite scaffold, the diameter of which was about 100–200 nm as shown by transmission electron microscopy analysis. The three-dimensional microstructure of the composite scaffold prepared in various ratios of HAp to SF was observed by scanning electron microscopy and the pore size of the optimal scaffold was about 30–120 μm. Meanwhile, the hemocompatibility of the composite scaffolds was evaluated based on their impact on the clotting function by way of activated partial thromboplastin time, prothrombin time and thromboelastographic assays. The scaffolds possessed a low hemolysis rate of red blood cells. Furthermore, cell culture tests using dental pulp stem cells found that the scaffolds had good biocompatibility. There biomimetic HAp/SF composite scaffolds may serve as a promising biomaterial for dental pulp repair.

Advances in magnetic recording technology have resulted in a rapid increase in disk capacities, but improvements in the mechanical characteristics of disks have been quite modest. For example, the access time to random disk blocks has decreased by a mere factor of two, while disk capacities have increased by several orders of magnitude. OLTP applications subject disks to a very demanding workload consisting of accesses to randomly distributed disk blocks and gain limited benefit from caching and prefetching (at the onboard disk cache). We propose some new disk scheduling methods to address the limited disk access bandwidth problem.Some well-known disk scheduling methods are: (i) FCFS. (ii) Shortest Seek Time First (SSTF). (iii) SCAN and Cyclical SCAN (CSCAN). The latter moves the disk arm to its beginning point after each SCAN so that requests at all disk cylinders are treated symmetrically. (iv) CSCAN with a lookahead of next i requests (CSCAN-LAi) takes into account latency to reorder their processing to minimize the sum of their service times. (v) Shortest Access Time First (SATF), which provides the best performance [2]. (vi) SATF with lookahead for i requests (SATF-LAi).In the case of SATF-LAi with i = 2 after the completion of request X the scheduler chooses requests A and B such that the sum of their service times processed consecutively, i.e., t X,A + at A,B , is minimized. In SATF with flexible lookahead only request A is definitely processed and request B is processed provided that it is selected in the next round. We refer to a as the discount factor (0 ≤ a ≤ 1), because less weight is attached to the service time of request B, since it may not be processed after request A. The case a = 0 corresponds to pure SATF. When a = 1 we consider a variant called SATF with fixed lookahead where B is processed unconditionally after A before any other other (perhaps more favorable recent) requests. Thus requests are processed two at a time, unless only one request is available. More generally requests in the temporal neighborhood of request A are given higher priority.