A Technique for Physiologically Age-Grading Female Stable Flies, Stomoxys calcitrans (L.)

A method of dissection followed by staining was initiated to allow physiological age- grading based on ovarian development in order to more completely describe the physiological development of adult female stable flies [Stomoxys calcitrans (L. )]. The gonotrophic developmental continuum from a non-differentiated cell in teneral females to mature eggs at the time of oviposition was first arbitrarily divided into six stages by using distinct landmarks within the developing oocyte . Then, nulliparous, uniparous, and biparous+ females were differentiated on the basis of the presence or absence of stained follicular relics in the ovariole sheaths. The combination of the two techniques made it possible to assign dissected adult female stable flies to one of 12 age-classes

A Technique for Physiologically Age-Grading Female Stable Flies, Stomoxys calcitrans (L.)

A method of dissection followed by staining was initiated to allow physiological age- grading based on ovarian development in order to more completely describe the physiological development of adult female stable flies [Stomoxys calcitrans (L. )]. The gonotrophic developmental continuum from a non-differentiated cell in teneral females to mature eggs at the time of oviposition was first arbitrarily divided into six stages by using distinct landmarks within the developing oocyte . Then, nulliparous, uniparous, and biparous+ females were differentiated on the basis of the presence or absence of stained follicular relics in the ovariole sheaths. The combination of the two techniques made it possible to assign dissected adult female stable flies to one of 12 age-classes

A storage and access architecture for efficient query processing in spatial database systems

Due to the high complexity of objects and queries and also due to extremely large data volumes, geographic database systems impose stringent requirements on their storage and access architecture with respect to efficient query processing. Performance improving concepts such as spatial storage and access structures, approximations, object decompositions and multi-phase query processing have been suggested and analyzed as single building blocks. In this paper, we describe a storage and access architecture which is composed from the above building blocks in a modular fashion. Additionally, we incorporate into our architecture a new ingredient, the scene organization, for efficiently supporting set-oriented access of large-area region queries. An experimental performance comparison demonstrates that the concept of scene organization leads to considerable performance improvements for large-area region queries by a factor of up to 150

How Market Ecology Explains Market Malfunction

Standard approaches to the theory of financial markets are based on equilibrium and efficiency. Here we develop an alternative based on concepts and methods developed by biologists, in which the wealth invested in a financial strategy is like the abundance of a species. We study a toy model of a market consisting of value investors, trend followers and noise traders. We show that the average returns of strategies are strongly density dependent, i.e. they depend on the wealth invested in each strategy at any given time. In the absence of noise the market would slowly evolve toward an efficient equilibrium, but the statistical uncertainty in profitability (which is adjusted to match real markets) makes this noisy and uncertain. Even in the long term, the market spends extended periods of time away from perfect efficiency. We show how core concepts from ecology, such as the community matrix and food webs, give insight into market behavior. The wealth dynamics of the market ecology explain how market inefficiencies spontaneously occur and gives insight into the origins of excess price volatility and deviations of prices from fundamental values.Comment: 9 pages, 5 figures, Conference on Evolutionary Models of Financial Markets, includes responses to reviewer

Ladino Clover For Rotation Pastures

Used in pasture mixtures, Ladino clover has shown most promise in northeast Iowa for dairy pastures. But you may expect satisfactory results wherever soil is fertile and well supplied with moisture

Is Frost Heaving Killing Your Legumes?

Frost heaving is a serious hazard to the maintenance of legume stands on many of our Iowa soils - especially on level claypan soils. But there are some things you can do to reduce your frost heaving losses