2,398 research outputs found
An Alternative to Using Fresh Alfalfa for Culturing \u3ci\u3eColias Philodice Eurytheme\u3c/i\u3e Boisduval (Lepidoptera: Pieridae)
Various artificial materials were implemented at each life stage of the alfalfa caterpillar, Colias philodice eurytheme Boisduval, to provide effective and economical replacements for alfalfa. Alfalfa substitutes were used for oviposition and feeding. We also developed a favorable laboratory mating environment. Also, the development of a method for removing disease organisms from eggs without increasing egg mortality was an essential facet of this work. The performance of individuals on artificial surfaces was compared with similar individuals reared on greenhouse alfalfa.
Green tape oriented at the top of oviposition cages or near some object which could be held on to while ovipositing was the most successful surface. Egg yields on green tape were comparable to those on alfalfa. A dilute bleach wash followed by two water washes required little time, yet provided adequate disease control, and all larval instars thrived on artificial diet. Methods for handling pupae and new adults and the favorable mating environment reduced colony maintenance time yet sumival rates insured propagation of the colony
Cellular solid behaviour of liquid crystal colloids. 1. Phase separation and morphology
We study the phase ordering colloids suspended in a thermotropic nematic
liquid crystal below the clearing point Tni and the resulting aggregated
structure. Small (150nm) PMMA particles are dispersed in a classical liquid
crystal matrix, 5CB or MBBA. With the help of confocal microscopy we show that
small colloid particles densely aggregate on thin interfaces surrounding large
volumes of clean nematic liquid, thus forming an open cellular structure, with
the characteristic size of 10-100 micron inversely proportional to the colloid
concentration. A simple theoretical model, based on the Landau mean-field
treatment, is developed to describe the continuous phase separation and the
mechanism of cellular structure formation.Comment: Latex 2e (EPJ style) EPS figures included (poor quality to comply
with space limitations
Calibration of a Water-Quality Model for Herrington Lake Using Empirically Derived Measurements of Phytoplankton Growth and Nutrient Assimilation
Importance of light limitation, nutrient availability, and hydrology in controlling the abundance and composition of the phytoplankton community of Herrington Lake (KY) was investigated over a two-year period. Selected environmental parameters were measured every two weeks (April-October) at five sampling stations located along the longitudinal gradient of the reservoir. In addition, short-term (48hr) nutrient enrichment experiments were conducted to assess the spatial and temporal variations in nutrient limitation. Phytoplankton growth responses to the combined addition of nitrogen (NO3) and phosphorus (PO4) were greater than those resulting from the addition of either nutrient alone. These results indicate that phytoplankton production was closely co-limited by the availability of both N and P. The magnitude of the phytoplankton responses to nutrient additions was greatest at downstream stations and in late summer suggesting that those populations experience more severe nutrient limitation. Significant interannual variations in nutrient limitation and primary production were observed during this study period (1995-1996). In 1995, nutrient limitation was more severe than in 1996. Above average rainfall and discharge in 1996 coincided with increased productivity (mg C/m3/hr) and minimal nutrient limitation. Phytoplankton community composition showed similar patterns of seasonal succession in both years
Effect of Cluster Formation on Isospin Asymmetry in the Liquid-Gas Phase Transition Region
Nuclear matter within the liquid-gas phase transition region is investigated
in a mean-field two-component Fermi-gas model. Following largely analytic
considerations, it is shown that: (1) Due to density dependence of asymmetry
energy, some of the neutron excess from the high-density phase could be
expelled into the low-density region. (2) Formation of clusters in the gas
phase tends to counteract this trend, making the gas phase more liquid-like and
reducing the asymmetry in the gas phase. Flow of asymmetry between the
spectator and midrapidity region in reactions is discussed and a possible
inversion of the flow direction is indicated.Comment: 9 pages,3 figures, RevTe
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