Tan spot disease of wheat: race characterization.

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Using Whole-Group Metabolic Rate and Behaviour to Assess the Energetics of Courtship in Red-Sided Garter Snakes

Reproductive effort is an important aspect of life history as reproductive success is arguably the most important component of fitness. Males tend to compete for access to females and, in the process, expend their energetic capital on mate searching, maleemale competition and courtship rather than directly on offspring. Red-sided garter snakes, Thamnophis sirtalis parietalis, are an exceptional model for studying energetic costs of courtship and mating as they fast during the spring mating season, which segregates the cost of energy acquisition from the cost of courtship and mating. However, measuring an individual male\u27s metabolic rate during courtship is complicated by the fact that male courtship behaviour in redsided garter snakes is dependent on both the detection of a female sexual attractiveness pheromone and on facilitated courtship (i.e. vigorous courtship is only exhibited in the presence of other males). Thus, traditional techniques of placing a mask over the head of individuals would prevent male courtship behaviour, and single animals placed in a flow-through chamber would not yield ecologically realistic levels of courtship, which are only seen in the context of a mating aggregation in this species. Because of these difficulties, we placed groups of males in a flow-through metabolic chamber together with a single female whose respiratory gases were vented outside the chamber to yield a whole-group metabolic rate during competitive courtship. We also measured the standard metabolic rates (SMR) of the males individually for comparison with active metabolic rates. Conservative estimates of peak group metabolic rates during courtship are 10e20 times higher than resting group metabolic rate, which was 1.88 times higher than SMR. These measurements, coupled with the fact that these males are aphagous during the breeding, indicates that costs of courtship may be high for males and has implications for the male mating tactics in this system

Oroko orthography development: Linguistic and sociolinguistic factors

This thesis explores the variety of linguistic and sociolinguistic factors that need to be considered in order to develop a good Oroko orthography. Oroko is a Bantu A language of the Southwest Province of Cameroon, Africa. The thesis starts with an overview of the Oroko\u27s location, population, classification, and language development status. The linguistic factors discussed are based largely on analyses of two lists: a 118-word list of nine Oroko dialects and an 821-word list of four Oroko dialects (included in the appendix). Consistent phonetic and phonemic alternations are examined in detail. The next chapter discusses the sociolinguistic issues that arise from participant observation, historical context, and two sociolinguistic surveys: a rapid assessment of the sociolinguistic situation among nine of the Oroko dialects and an extendibility survey using a modified form of recorded text testing (RTT) done in six dialects. The next chapter opens with a discussion of a number of options for standardizing or not standardizing across all the Oroko dialects, concluding that the various dialects are different enough to require at least introductory material to be written in at least four dialects. Then, the various linguistic and sociolinguistic factors are drawn together to form the basis for orthographic recommendations. This chapter concludes with a discussion of the practical issues of presenting these recommendations to the Oroko

Neuronal Control of Swimming Behavior: Comparison of Vertebrate and Invertebrate Model Systems

Swimming movements in the leech and lamprey are highly analogous, and lack homology. Thus, similarities in mechanisms must arise from convergent evolution rather than from common ancestry. Despite over 40 years of parallel investigations into this annelid and primitive vertebrate, a close comparison of the approaches and results of this research is lacking. The present review evaluates the neural mechanisms underlying swimming in these two animals and describes the many similarities that provide intriguing examples of convergent evolution. Specifically, we discuss swim initiation, maintenance and termination, isolated nervous system preparations, neural-circuitry, central oscillators, intersegmental coupling, phase lags, cycle periods and sensory feedback. Comparative studies between species highlight mechanisms that optimize behavior and allow us a broader understanding of nervous system function

Technology, Taphonomy, and Seasonality: Understanding Differences between Dorset and Thule Subsistence Strategies at Iqaluktuuq, Victoria Island

This paper examines differences between Late Dorset and Thule Inuit subsistence economies at the Bell site on Victoria Island, Nunavut. This location is relatively unusual in the eastern Arctic region because local subsistence was based largely on caribou and fish, rather than the sea mammals that dominate in most other regions. For both periods, animal bone samples are quantified in terms of taxonomic frequencies, element (body part) distributions, seasonality, prey demography, and bone modifications such as cutting, burning, and gnawing. A comparison between the periods indicates many broad similarities in subsistence, but some subtle differences suggest that the Thule had a more focal and specialized economy, with a slightly different seasonal profile.Le présent article porte sur les différences entre l’économie de subsistance du Dorsétien récent et l’économie de subsistance des Inuits thuléens au site Bell de l’île Victoria, au Nunavut. Cet emplacement de la région est de l’Arctique est assez inhabituel en ce sens que la subsistance de la région reposait grandement sur le caribou et le poisson, et non pas sur les mammifères marins qui dominent la plupart des autres régions. Pour ces deux périodes, les échantillons d’ossements d’animaux sont quantifiés en fonction des fréquences taxonomiques, de la répartition des éléments (restes), de leur saisonnalité, de la démographie des proies et des altérations subies par les os, comme les marques de coupure, de brûlure et de rongement. La comparaison des périodes permet de remarquer de nombreuses similitudes générales sur le plan de la subsistance, mais certaines différences subtiles suggèrent que les Thuléens avaient une économie plus concentrée et spécialisée de même qu’un profil saisonnier légèrement différent

Local adaptation drives the diversification of effectors in the fungal wheat pathogen Parastagonospora nodorum in the United States

Filamentous fungi rapidly evolve in response to environmental selection pressures in part due to their genomic plasticity. Parastagonospora nodorum, a fungal pathogen of wheat and causal agent of septoria nodorum blotch, responds to selection pressure exerted by its host, influencing the gain, loss, or functional diversification of virulence determinants, known as effector genes. Whole genome resequencing of 197 P. nodorum isolates collected from spring, durum, and winter wheat production regions of the United States enabled the examination of effector diversity and genomic regions under selection specific to geographically discrete populations. 1,026,859 SNPs/InDels were used to identify novel loci, as well as SnToxA and SnTox3 as factors in disease. Genes displaying presence/absence variation, predicted effector genes, and genes localized on an accessory chromosome had significantly higher pN/pS ratios, indicating a higher rate of sequence evolution. Population structure analyses indicated two P. nodorum populations corresponding to the Upper Midwest (Population 1) and Southern/Eastern United States (Population 2). Prevalence of SnToxA varied greatly between the two populations which correlated with presence of the host sensitivity gene Tsn1 in the most prevalent cultivars in the corresponding regions. Additionally, 12 and 5 candidate effector genes were observed to be under diversifying selection among isolates from Population 1 and 2, respectively, but under purifying selection or neutrally evolving in the opposite population. Selective sweep analysis revealed 10 and 19 regions that had recently undergone positive selection in Population 1 and 2, respectively, involving 92 genes in total. When comparing genes with and without presence/absence variation, those genes exhibiting this variation were significantly closer to transposable elements. Taken together, these results indicate that P. nodorum is rapidly adapting to distinct selection pressures unique to spring and winter wheat production regions by rapid adaptive evolution and various routes of genomic diversification, potentially facilitated through transposable element activity

Mancha amarela do trigo: caracterização de raças.

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