ORDINARY AND GENERALIZED STOCHASTIC DOMINANCE: A PRIMER

Research Methods/ Statistical Methods,

Influence of pesticides on pathogen populations and biological control agents

Non-Peer Reviewe

Self Calibration of Tomographic Weak Lensing for the Physics of Baryons to Constrain Dark Energy

Numerical studies indicate that uncertainties in the treatment of baryonic physics can affect predictions for shear power spectra at a level that is significant for forthcoming surveys such as DES, SNAP, and LSST. Correspondingly, we show that baryonic effects can significantly bias dark energy parameter measurements. Eliminating such biases by neglecting information in multipoles beyond several hundred leads to weaker parameter constraints by a factor of approximately 2 to 3 compared with using information out to multipoles of several thousand. Fortunately, the same numerical studies that explore the influence of baryons indicate that they primarily affect power spectra by altering halo structure through the relation between halo mass and mean effective halo concentration. We explore the ability of future weak lensing surveys to constrain both the internal structures of halos and the properties of the dark energy simultaneously as a first step toward self calibrating for the physics of baryons. This greatly reduces parameter biases and no parameter constraint is degraded by more than 40% in the case of LSST or 30% in the cases of SNAP or DES. Modest prior knowledge of the halo concentration relation greatly improves even these forecasts. Additionally, we find that these surveys can constrain effective halo concentrations near m~10^14 Msun/h and z~0.2 to better than 10% with shear power spectra alone. These results suggest that inferring dark energy parameters with measurements of shear power spectra can be made robust to baryonic effects and may simultaneously be competitive with other methods to inform models of galaxy formation. (Abridged)Comment: 18 pages, 11 figures. Minor changes reflecting referee's comments. Results and conclusions unchanged. Accepted for publication in Physical Review

Ketorolac Use and Incidence of Postoperative Bleeding in an ERAS Colorectal Surgical Population: A Quality Analysis of Practice

Background Ketorolac is an effective analgesic adjunct and is currently used in Enhanced Recovery After Surgery (ERAS) protocols. However, investigation into its safety profile is warranted in specific surgical populations. This Quality Improvement (QI) study sought to examine the association of ketorolac to increased postoperative bleeding risk, increased postoperative renal impairment, and 30-day readmission within an ERAS protocol for colorectal surgery. Methods A retrospective review was conducted of 158 patients enrolled in an existing ERAS protocol for colorectal surgery with at least one dose of ketorolac administered in the perioperative period. Outcomes of postoperative bleeding, 30-day readmission, and preoperative/postoperative serum creatinine levels were assessed. Results There was no statistically significant difference in the incidence of postoperative bleeding compared to a known population. There was a significant association of 30-day readmissions with documented evidence of bleeding (P = 0.037). There was no significant change in the preoperative and postoperative serum creatinine. Multivariate logistic regression analysis found no association of postoperative bleeding with pre-existing chronic non-steroidal anti-inflammatory drug (NSAID) use or preoperative serum creatinine. Conclusions Ketorolac is not associated with an increased risk of postoperative bleeding in colorectal ERAS surgical patients. However, postoperative bleeding does predict the likelihood for 30-day readmissions

Economics of alternative input use and crop diversity strategies in the Dark Brown Soil Zone of Saskatchewan

Non-Peer Reviewe

Tillage system and cropping sequence effects on common root rot of barley in eastern Saskatchewan

Non-Peer ReviewedFusarium head blight (FHB) in barley has been spreading on the Canadian Prairies for the last decade. Fusarium spp. causing FHB can also cause crown/root rot of cereal crops. It is therefore of interest to determine the impact of agronomic practices on fungal populations associated with root rot of barley. From 1999 to 2001, 137 barley crops were sampled in eastern Saskatchewan for severity of subcrown internode discoloration and percent isolation of fungi. Cochliobolus sativus was the most commonly isolated fungus, whereas the most commonly isolated Fusarium spp. included the FHB pathogens F. avenaceum, F. culmorum and F. graminearum. Discoloration caused by C. sativus was favored by conventional-till, whereas Fusarium spp. increased in reduced tillage systems. Barley grown after a cereal-summerfallow (or summefallow-cereal) sequence under conventional- or minimum-till had increased levels of C. sativus. Fusarium spp. were most affected by the previously grown crop(s); they were more common in barley grown after a noncereal than a cereal, and after two noncereals, or a noncereal alternated with summerfallow. Previous glyphosate applications were associated with lower C. sativus, and higher Fusarium spp., levels in barley grown under minimum till. This suggests changes in fungal communities; however, the mechanism(s) responsible for these changes in fungal levels are not known. Increased infection of ground/underground tissue by FHB pathogens might contribute to its development in succeeding cereal crops, therefore measures aimed at reducing root/crown infections by Fusarium spp. might also help reduce FHB development

Effects of input level and crop diversity on energy use efficiency of cropping systems in the Dark Brown Soil Zone

Non-Peer Reviewe

Trends in crop production in the Canadian prairies

Non-Peer ReviewedDryland agriculture in the Canadian prairies is continuously confronted by change. In response to growing competition in the global market place producers have sought alternative crop production methods in order to maintain their farming enterprises. Driving the change has been lower prices for cereal grains, declining input costs (e.g., glyphosate), changes in government policies and programs (e.g., grain transportation, farm safety net programs), new markets and value-added opportunities, improvements in machinery design and soil management practices, and growing concern about soil and environmental degradation. This study examines the trends in crop production in the Canadian prairies over the last two and a half decades (1976 to 1998). The focus is on both cropping choice and tillage practices for the major soil climatic zones in western Canada

Tillage system and cropping sequence effects on Fusarium head blight in barley in eastern Saskatchewan

Non-Peer ReviewedFusarium head blight (FHB) in barley is well established in the eastern Canadian Prairies and appears to be moving westward. A survey of 192 barley crops in eastern Saskatchewan was conducted to determine the impact of agronomic practices on FHB (1999-2002) and Fusarium damaged kernels (FDK) (2000-2001). The most common species isolated from spikes/kernels were F. sporotrichioides, F. avenaceum, and F. graminearum, followed by F. poae and F. culmorum. Disease tended to be higher under minimum- than conventional- and/or zero-till. F. sporotrichioides was favored by a previous cereal crop, whereas F. avenaceum was higher after a pulse crop, and F. graminearum decreased after a pulse but not an oilseed crop. The latter two pathogens were also more prevalent after diversified cropping sequences than after two cereal crops. Summerfallow, or summerfallow alternated with cereals, decreased FDK. Previous glyphosate (Group 9 herbicides) use was associated with increased infection by all Fusarium spp., whereas Group 1 herbicides were associated with increased infection by F. poae and F. sporotrichioides. Number of previous glyphosate applications was also correlated with FHB caused by F. avenaceum and F. graminearum. We concluded that in eastern Saskatchewan, barley grown under minimum-till where glyphosate had been sprayed and following diversified cropping sequences would sustain the greatest damage due to FHB/FDK caused by F. avenaceum and F. graminearum