2,679 research outputs found
Mating system and population genetic structure of the bulldog ant Myrmecia pavida
Understanding the evolution of the alternative mating strategies of monandry and polyandry is a fundamental problem in evolutionary biology because of the cost-benefit trade-offs associated with mating for females. The problem is particularly intriguing in the social insects because queens in most species appear to be obligately monandrous (i.e., only a single male fathers their offspring), while those in a minority of species have evolved high, and sometimes extreme, polyandry. One group which may shed particular insight is the ant subfamily Myrmeciinae (Myrmecia and Nothomyrmecia). Here we examine the population and colony genetic structure of the bulldog ant Myrmecia pavida CLARK, 1951 by genotyping offspring workers from 45 colonies. We find little evidence of geographic structuring or inbreeding in the population, indicating that the species outbreeds, most probably in mating swarms. We also find that queens of M pavida show moderately high polyandry, with 84% having mated with between two and seven males, and an overall mean observed mating frequency of 3.8. This is significantly higher than previously reported for queens of Nothomyrmecia macrops, in which most females mate singly. This was similar to that of M pyriformis, M brevinoda, and M pilosula, the three congenerics for which mating frequencies have recently been reported. The two genera in the Myrmeciinae therefore appear to show multiple transitions in mating frequency and further investigation of the subfamily may be highly informative for disentangling the forces driving the evolution of alternative mating strategies
Distribution of the Economic Gains of the 1990s
„h Australia¡¦s surge in productivity growth in the 1990s fuelled an acceleration in growth in total income and average income (income per person in Australia). ¡V Annual average income growth accelerated from 1.4 per cent in the 1970s and 1980s to 2.5 per cent in the 1990s. ¡V Faster productivity growth accounted for over 90 per cent of the acceleration. „h The income growth of the 1990s was distributed evenly between labour (wages and salaries) and capital (profits). The labour and capital shares in economywide income were stable throughout the 1990s. Concerns that productivity-enhancing factors have adversely affected the income-earning potential of labour appear to be unfounded at the aggregate level.economic gains - distribution - living standards - income - productivity - employment - wealth - consumption - education - health - housing - environment - working hours
Examining the Teacher Perceptions, Implementations, Barriers, and Benefits Associated with the Missouri Reading Initiative
Reading is an essential skill taught during elementary academic years. The Sunny Day School District recognized the need of locating a reading program tailored to effectively meeting the instructional needs of students. A preliminary question was, “how do we increase the reading achievement of all our students?” In response to this instructional concern, the Sunny Day School District decided to implement the Missouri Reading Initiative (MRI), a state program created to assist teachers with scientifically research based reading instructional strategies. This study addressed the problem of a lack of a program evaluation for the MRI program as implemented within the elementary schools of the Sunny Day School District.
Qualitative and quantitative approaches added depth and authenticity to the data collection process and the intention was to triangulate the data in order to obtain a holistic picture of the MRI program in one school district. Design features were inclusive of the following study elements: administrative interviews, surveys, classroom observations, and MAP Scale Scores. Statistical tools used to analyze the MAP Scale Scores comprised of two z-tests for proportions calculated to find differences in opinions and an ANOVA to find any variances between MAP Scale Scores of grades 3-5 during the years of this research study
An alignment of the research questions, observations, and surveys to the interview questions was completed then linked with the literature. Interviews and observations revealed valuable details of the implementation process of the MRI program. Emerging themes added data about the implementation processes and were reflective of management and classroom facilitation. Survey results did suggest MRI was beneficial for assisting teachers with research based instructional strategies. Two z tests for proportions of the survey results were in the critical range causing the rejection of the null hypotheses. An ANOVA of the MAP scores did not show a significant change in any one year over the five-year period. Before deciding on implementing an extensive reading program similar to MRI, other districts carefully consider the evaluation methods of teachers. Factors not considered in this study, such as evaluative measures (cognitive coaching versus traditional methods), may yield different program implementation results
Substrate Influences Temperature Sensitivity of Dissolved Organic Carbon (DOC) and Nitrogen (DON) Mineralization in Arid Agricultural Soils
The bioavailability of nitrogen (N) in soil relies on the progressive breakdown of necromass protein to peptide and amino acid components and conversion to inorganic N forms. We understand the fluxes and pathways of the N cycle downstream from amino acids, but our understanding of the factors controlling peptide and amino acid mineralization, particularly in arid soils, is lacking. We investigated the influence of temperature on the rate of dissolved organic carbon (DOC) and nitrogen (DON) cycling in three agricultural soils from Saudi Arabia. Although the physical and chemical properties of the soils differed markedly, phospholipid fatty acid (PLFA) analysis revealed they had similar topsoil and subsoil microbial communities. Soils behaved similarly in terms of the rate of substrate use, microbial C-use efficiency, and response to temperature. Substrate mineralization rate increased with temperature with more C being allocated to microbial catabolic rather than anabolic processes. Our results show that climate change is likely to lead to changes in soil organic matter turnover and shift C allocation patterns within the soil microbial community. This is expected to reduce soil quality and exacerbate nutrient losses. Management strategies are required to promote the retention of organic matter in these soils
Faculty Input in Evaluation for a College with Many Disciplines
The co-presenters will describe how faculty in one academic unit of a large College combining many academic disciplines were tasked with examining best practices and development of a faculty merit performance evaluation rubric. Perspective on the project will be offered by the initiating School Director, Dean of the College and Associate Dean of the College
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