Impacts of Mowing Treatments on Smooth Bromegrass (Bromus inermis) Belowground Bud Bank

Introduced in the 1880s for improving forage production and controlling soil erosion, smooth bromegrass (Bromus inermis Leyss) has invaded and is threating numerous native prairie ecosystems and wildlife habitats in the Northern Great Plains. Land managers of the mixed-grass prairie ecosystems currently spend significant resources attempting to control invasive species and restore native grasslands with various management strategies including grazing, prescribed burning, herbicide application and seeding native species. Unfortunately, many studies have showed that such management efforts have minimal short-term effects. Without sustained effort, persistence and resurgence of smooth bromegrass is inevitable

Monitoring and Evaluation of Supplemented Spring Chinook Salmon and Life Histories of Wild Summer Steelhead in the Grande Ronde Basin, 2007 Annual Report.

This is the ninth annual report for a multi-year project designed to monitor and evaluate supplementation of endemic spring Chinook salmon in Catherine Creek and the upper Grande Ronde River. These two streams historically supported anadromous fish populations that provided significant tribal and non-tribal fisheries, but in recent years, have experienced severe declines in abundance. Conventional and captive broodstock supplementation methods are being used to restore these spring Chinook salmon populations. Spring Chinook salmon populations in Catherine Creek and the upper Grande Ronde River, and other streams in the Snake River Basin have experienced severe declines in abundance over the past two decades (Nehlsen et al. 1991). A supplementation program was initiated in Catherine Creek and the upper Grande Ronde River, incorporating the use of both captive and conventional broodstock methods, in order to prevent extinction in the short term and eventually rebuild populations. The captive broodstock component of the program (BPA Project 199801001) uses natural-origin parr collected by seining and reared to maturity at facilities near Seattle, Washington (Manchester Marine Laboratory) and Hood River, Oregon (Bonneville Hatchery). Spawning occurs at Bonneville Hatchery, and resulting progeny are reared in hatcheries. Shortly before outmigration in the spring, juveniles are transferred to acclimation facilities. After an acclimation period of about 2-4 weeks, volitional release begins. Any juveniles remaining after the volitional release period are forced out. The conventional broodstock component uses returning adults collected at traps near the spawning areas, transported to Lookingglass Hatchery near Elgin, Oregon, held, and later spawned. The resulting progeny are reared, acclimated, and released similar to the captive broodstock component. All progeny released receive one or more marks including a fin (adipose) clip, codedwire tag, PIT tag, or visual implant elastomer tag. The numbers of adults used for conventional broodstock are determined by an agreement among comanagers (Zimmerman and Patterson 2002). Activities for this project focus on two life stages of spring Chinook salmon: juveniles during the migration from freshwater to the ocean and adults during prespawning migration through the end of spawning. Life history, production, and genetics are monitored and used to evaluate program effectiveness

First cohomology for finite groups of Lie type: simple modules with small dominant weights

Let $k$ be an algebraically closed field of characteristic $p > 0$, and let $G$ be a simple, simply connected algebraic group defined over $\mathbb{F}_p$. Given $r \geq 1$, set $q=p^r$, and let $G(\mathbb{F}_q)$ be the corresponding finite Chevalley group. In this paper we investigate the structure of the first cohomology group $H^1(G(\mathbb{F}_q),L(\lambda))$ where $L(\lambda)$ is the simple $G$-module of highest weight $\lambda$. Under certain very mild conditions on $p$ and $q$, we are able to completely describe the first cohomology group when $\lambda$ is less than or equal to a fundamental dominant weight. In particular, in the cases we consider, we show that the first cohomology group has dimension at most one. Our calculations significantly extend, and provide new proofs for, earlier results of Cline, Parshall, Scott, and Jones, who considered the special case when $\lambda$ is a minimal nonzero dominant weight.Comment: 24 pages, 5 figures, 6 tables. Typos corrected and some proofs streamlined over previous versio

Second cohomology for finite groups of Lie type

Let $G$ be a simple, simply-connected algebraic group defined over $\mathbb{F}_p$. Given a power $q = p^r$ of $p$, let $G(\mathbb{F}_q) \subset G$ be the subgroup of $\mathbb{F}_q$-rational points. Let $L(\lambda)$ be the simple rational $G$-module of highest weight $\lambda$. In this paper we establish sufficient criteria for the restriction map in second cohomology $H^2(G,L(\lambda)) \rightarrow H^2(G(\mathbb{F}_q),L(\lambda))$ to be an isomorphism. In particular, the restriction map is an isomorphism under very mild conditions on $p$ and $q$ provided $\lambda$ is less than or equal to a fundamental dominant weight. Even when the restriction map is not an isomorphism, we are often able to describe $H^2(G(\mathbb{F}_q),L(\lambda))$ in terms of rational cohomology for $G$. We apply our techniques to compute $H^2(G(\mathbb{F}_q),L(\lambda))$ in a wide range of cases, and obtain new examples of nonzero second cohomology for finite groups of Lie type.Comment: 29 pages, GAP code included as an ancillary file. Rewritten to include the adjoint representation in types An, B2, and Cn. Corrections made to Theorem 3.1.3 and subsequent dependent results in Sections 3-4. Additional minor corrections and improvements also implemente

Prevalence of Tritrichomonas foetus in beef bulls slaughtered at two abattoirs in northern Australia

Bovine trichomoniasis, caused by the protozoal parasite Tritrichomonas foetus, is a highly contagious venereal disease characterised by early pregnancy loss, abortion and pyometra. Persistently infected bulls and cows are the primary reservoirs of infection in infected herds. This research investigated the prevalence of T. foetus infection in bulls from properties located across northern Australia and New South Wales. Preputial samples were collected from 606 bulls at slaughter and tested for T. foetus using the VetMAX-Gold Trich Detection Kit (Thermo Fisher Scientific). The apparent prevalence of T. foetus infection varied between regions, with northern regions in the Northern Territory, Queensland and Western Australia showing a prevalence of 15.4%, 13.8% and 11.4%, respectively. There was some evidence of an association between infection and postcode (P = 0.06) and increasing bull age (P = 0.054). This study confirms that T. foetus infection is likely to be present in many beef breeding herds and contributing to lower than expected reproductive performance, particularly across northern Australia