New Summer Forage Legumes for Texas

Last updated: 6/12/200

First Report of \u3ci\u3ePythium ultimum, P. irregulare, Rhizoctonia solani\u3c/i\u3e AG4, and \u3ci\u3eFusarium proliferatum\u3c/i\u3e from Arrowleaf Clover (\u3ci\u3eTrifolium vesiculosum\u3c/i\u3e): A Disease Complex

Poor stand establishment, failure to recover after grazing, and premature plant death have reduced the utilization of arrowleaf clover (Trifolium vesiculosum Savi) as a forage crop in the southeastern United States in recent years. Clover plants collected from poor stands in east Texas pastures during the 1995 to 1996 and 1996 to 1997 seasons first exhibited root disease symptoms as young seedlings in the fall. Symptoms consisted of one or more of the following: tan discoloration of lateral roots and taproot; root pruning; and small, tan, sunken lesions on the taproot and crown. Many Rhizobium nodules were brown and dead. Toward spring, symptoms increased in severity. Root lesions became larger and darker, and internal crown discoloration was observed. Disease incidence reached 100% in both growing seasons. Premature death of plants also was observed, especially in pastures where plants had been grazed

First Report of \u3ci\u3ePythium ultimum, P. irregulare, Rhizoctonia solani\u3c/i\u3e AG4, and \u3ci\u3eFusarium proliferatum\u3c/i\u3e from Arrowleaf Clover (\u3ci\u3eTrifolium vesiculosum\u3c/i\u3e): A Disease Complex

Poor stand establishment, failure to recover after grazing, and premature plant death have reduced the utilization of arrowleaf clover (Trifolium vesiculosum Savi) as a forage crop in the southeastern United States in recent years. Clover plants collected from poor stands in east Texas pastures during the 1995 to 1996 and 1996 to 1997 seasons first exhibited root disease symptoms as young seedlings in the fall. Symptoms consisted of one or more of the following: tan discoloration of lateral roots and taproot; root pruning; and small, tan, sunken lesions on the taproot and crown. Many Rhizobium nodules were brown and dead. Toward spring, symptoms increased in severity. Root lesions became larger and darker, and internal crown discoloration was observed. Disease incidence reached 100% in both growing seasons. Premature death of plants also was observed, especially in pastures where plants had been grazed

Time of Harvest of Lablab and Cowpeas on Production and Nutritive Value of Leaf and Stem Components

Last updated: 6/9/200

Effect of Seeding Rate of Cowpeas and Lablab on Dry Matter Production and Nutritive Value

Last updated: 6/9/200

Estimating the functional form for the density dependence from life history data

Two contrasting approaches to the analysis of population dynamics are currently popular: demographic approaches where the associations between demographic rates and statistics summarizing the population dynamics are identified; and time series approaches where the associations between population dynamics, population density, and environmental covariates are investigated. In this paper, we develop an approach to combine these methods and apply it to detailed data from Soay sheep (Ovis aries). We examine how density dependence and climate contribute to fluctuations in population size via age- and sex-specific demographic rates, and how fluctuations in demographic structure influence population dynamics. Density dependence contributes most, followed by climatic variation, age structure fluctuations and interactions between density and climate. We then simplify the density-dependent, stochastic, age-structured demographic model and derive a new phenomenological time series which captures the dynamics better than previously selected functions. The simple method we develop has potential to provide substantial insight into the relative contributions of population and individual-level processes to the dynamics of populations in stochastic environments

Activation of α7 nicotinic receptors improves phencyclidine-induced deficits in cognitive tasks in rats: Implications for therapy of cognitive dysfunction in schizophrenia

YesRationale: Nicotinic α7 acetylcholine receptors (nAChRs) have been highlighted as a target for cognitive enhancement in schizophrenia. Aim: To investigate whether the deficits induced by sub-chronic phencyclidine (PCP) in reversal learning and novel object recognition could be attenuated by the selective α7 nAChR full agonist, PNU-282987. Methods: Adult female hooded-Lister rats received sub-chronic PCP (2 mg/kg) or vehicle i.p. twice daily for seven days, followed by 7-days washout. In cohort 1, PCP-treated rats then received PNU-282987 (5, 10, 20 mg/kg; s.c.) or vehicle and were tested in the reversal learning task. In cohort 2, PCP-treated rats received PNU-282987 (10 mg/kg; s.c.) or saline for 15 days and were tested in the novel object recognition test on day 1 and on day 15, to test for tolerance. Results: Sub-chronic PCP produced significant deficits in both cognitive tasks (P<0.01-0.001). PNU-282987 attenuated the PCP-induced deficits in reversal learning at 10 mg/kg (P<0.01) and 20 mg/kg (P<0.001), and in novel object recognition at 10 mg/kg on day 1 (P<0.01) and on day 15 (P<0.001). Conclusions: These data show that PNU-282987 has efficacy to reverse PCP-induced deficits in two paradigms of relevance to schizophrenia. Results further suggest that 15 day daily dosing of PNU-282987 (10 mg/kg s.c.) does not cause tolerance in rat. This study suggests that activation of α7 nAChRs, may represent a suitable strategy for improving cognitive deficits of relevance to schizophrenia.SL McLean was supported by a joint University of Bradford–GSK postgraduate studentship

PNU-120596, a positive allosteric modulator of α7 nicotinic acetylcholine receptors, reverses a sub-chronic phencyclidineinduced cognitive deficit in the attentional set-shifting task in female rats

yThe α7 nicotinic acetylcholine receptors (nAChRs) have been highlighted as a target for cognitive enhancement in schizophrenia. Adult female hooded Lister rats received sub-chronic phencyclidine (PCP) (2mg/kg) or vehicle i.p. twice daily for 7 days, followed by 7 days’ washout. PCP-treated rats then received PNU-120596 (10mg/kg; s.c.) or saline and were tested in the attentional set-shifting task. Sub-chronic PCP produced a significant cognitive deficit in the extra-dimensional shift (EDS) phase of the task (p < 0.001, compared with vehicle). PNU-120596 significantly improved performance of PCP-treated rats in the EDS phase of the attentional set-shifting task (p < 0.001). In conclusion, these data demonstrate that PNU-120596 improves cognitive dysfunction in our animal model of cognitive dysfunction in schizophrenia, most likely via modulation of α7 nACh receptors.This work was partially funded by Johnson & Johnson Pharmaceutical Research and Development