The Effect of Repeated Low Temperature on Eggs of the Alfalfa Weevil (Coleoptera: Curculionidae)

Three ages of alfalfa weevil, Hypera postica (Gyllenhal) eggs were exposed to repeated exposures of -15 and -20°C. Fresh-laid eggs were quite susceptible and 3- and 5day old eggs were relatively resistant to -15\u27C, but all ages of eggs showed considerable susceptibility to -20°C, with an average LT50 of 2.2 days. Comparison of this data with similar studies utilizing constant low temperature exposures showed the effect to be independent of temporal interruptions

Use with Caution: Interpreting Consumer Expenditure Income Group Data

Economic well-being has been an issue relevant to American public discourse for some time and has become a topic of particular interest among journalists, policymakers, and ordinary American families. The Consumer Expenditure Survey (CE) is often used as a tool to analyze the effects of economic well-being. Though the Census Bureau independently collects and processes income data—the CE is the only Federal survey that collects information on income, expenditures, and associated demographic characteristics from U.S. consumers. As a result, CE data are useful for answering many salient questions related to economic well-being. However, CE data are also complex and should be used with an understanding of the limitations of these data. This Beyond the Numbers article examines assumptions users often make regarding how the CE measures household wealth, by providing examples of the nuances in the data and composition of five household groupings. The examples provide a clearer snapshot of economic well-being found in the income quintiles. The article uses tabulations of households by quintiles of income before taxes that many researchers use to identify the “poor” and the “rich” in the CE data. These terms are subjective and potentially pejorative. Another common set of terms for these types of analyses are “low-income” and “high-income.” These are also subjective terms, and they are imprecise for communicating the concept of economic well-being, which involves other measures of wealth (e.g. stocks, bonds, cash assets, etc.). Misunderstandings arise potentially when researchers use terms like “rich” and “poor” to describe households rather than focus solely on income measures. So, what are the common assumptions made about the economic well-being of the “poor” and “rich” when using CE data to compare income groups

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

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

Calibrated, cosmological hydrodynamical simulations with variable IMFs I: Method and effect on global galaxy scaling relations

The recently inferred variations in the stellar initial mass function (IMF) among local highmass early-type galaxies may require a reinterpretation of observations of galaxy populations and may have important consequences for the predictions of models of galaxy formation and evolution. We present a new pair of cosmological, hydrodynamical simulations based on the EAGLE model that self-consistently adopts an IMF that, respectively, becomes bottomor top-heavy in high-pressure environments for individual star-forming gas particles. In such models, the excess stellarmass-to-light (M/L) ratio with respect to a reference IMF is increased due to an overabundance of low-mass dwarf stars or stellar remnants, respectively. Crucially, both pressure-dependent IMFs have been calibrated to reproduce the observed trends of increasing excessM/L with central stellar velocity dispersion (σe) in early-type galaxies, while maintaining agreement with the observables used to calibrate the EAGLE model, namely the galaxy luminosity function, half-light radii of late-type galaxies, and black holemasses.We find that while theM/L excess is a good measure of the IMF for low-mass slope variations, it depends strongly on the age of the stellar population for high-mass slope variations. The normalization of the [Mg/Fe]-σerelation is decreased (increased) for bottom- (top-)heavy IMF variations, while the slope is not strongly affected. Bottom-heavy variations have little impact on galaxy metallicities, half-light radii of early-type galaxies, or star formation rates, while top-heavy variations significantly increase these quantities for high-mass galaxies, leading to tension with observations. © 2018 The Author(s). Published by Oxford University Press on behalf of The Royal Astronomical Society