21,837 research outputs found
The Use of an Anthrone Reagent to Detect Sugar Meals and Their Persistence in the Mosquito \u3ci\u3eAedes Triseriatus\u3c/i\u3e (Diptera: Culicidae)
Adults of Aedes triseriatus were fed water, blood, and 10% pure and mixed solutions of glucose, fructose and sucrose. Adults were tested for fructose by the cold-anthrone test 0, 1, 4, 12, and 24 h after feeding. Water-fed males and females and blood-fed females were anthrone negative. Glucose-fed males were anthrone negative but some glucose-fed females were weakly anthrone positive immediately after feeding. Many adults fed a mixture of glucose, fructose and sucrose were anthrone negative 12 h after feeding and all were anthrone negative after 24 h. The interpretation of negatives in the anthrone test is discussed with respect to the dynamics of nectar feeding, metabolic rates and sampling regimes
The Age Structure of a Population of \u3ci\u3eAedes Provocans\u3c/i\u3e (Diptera: Culicidae) in Southwestern Ontario
In a previous paper it was shown that an eastern-Ontario population of the early-spring mosquito Aedes provocans had an atypical age structure: the adult-female population aged rapidly and synchronously, achieving an advanced gonotrophic age in an unusually brief period of time. The present study examined the age structure of Ae. provocans near Waterloo, in south-western Ontario, at a site at which adult emergence occurred over a wider, more variable period and at which the preferred nectar sources for young adults were much less abundant. In Waterloo, the adult-female population aged more slowly and much less synchronously than in eastern Ontario. The role of resources, particularly nectar, in leading to delayed aging, is discussed
Vegetation response to cattail management at Cheyenne Bottoms, Kansas
Dense, monospecific cattail (Typha spp.) stands are a problem in many prairie wetlands because they alter habitat
structure and function, resulting in a decrease in use by wildlife species. Cheyenne Bottoms Wildlife Area, a Wetland of International Importance in central Kansas, has experienced a large increase in cattails and a subsequent decrease in migratory wetland bird use. As a consequence, intensive cattail management is practiced. We assessed the effectiveness of prescribed burning, discing following prescribed burning, and cattle grazing following prescribed burning at two stocking rates of 5 and 20 head per 11 ha in suppressing cattail, as well as the effects of these treatments on non-cattail vegetation
Survey of Material for an Infrared-Opaque Coating
More than 40 reflectance spectra in the range from 20 to 500 microns have been obtained for a variety of coatings, binders, and additives to identify promising components of an infrared-opaque coating for the Space Infrared Telescope Facility. Certain combinations of materials showed a specular reflectance below 0.1 throughout the spectral range measured. In addition to estimating the optical constants of several combination coatings, this survey also supports three qualitative conclusions: (1) promising off-the-shelf binders of different additives are Chemglaze Z-306, ECP-2200, and De Soto Black; (2) carbon black is very effective in reducing far-infrared reflectance; (3) the far-infrared reflectance from coatings containing 80 SiC grit is consistently lower than that from similar coatings containing TiBr powder
Targeting foreclosure interventions: an analysis of neighborhood characteristics associated with high foreclosure rates in two Minnesota counties
This study examines the statistical association of foreclosure sales with social, economic and housing variables measured at the Census tract level for two purposes of interest to foreclosure mitigation practitioners â- to assess whether it is feasible to identify in advance neighborhoods likely to have high rates of foreclosure, and to explore the socioeconomic traits of high-foreclosure neighborhoods so as to design appropriate mitigation programs. We collected data on foreclosure sales in 2002 from the sheriffâs departments of Hennepin and Ramsey counties, the two core counties that comprise the Minneapolis-St. Paul MSA. We find that several factors commonly associated with high foreclosure sale rates could have correctly identified, in advance, most neighborhoods with high rates of mortgage foreclosure. To guide the design of foreclosure mitigation programs, we also present evidence that foreclosure risks in our two counties were highest in neighborhoods with elevated credit risk indicators and a high proportion of homeowners who are recent minority buyers or young. We show that an accurate credit risk variable is among the best predictors of foreclosure and also critically affects our multivariate analysis of factors associated with foreclosure. To limit social losses associated with foreclosures, we conclude that consideration should be given to enhancing public access to data on mortgages, foreclosures, and foreclosure risk factors, especially the neighborhood distribution of credit scores.
Temporal Variations of Strength and Location of the South Atlantic Anomaly as Measured by RXTE
The evolution of the particle background at an altitude of ~540 km during the
time interval between 1996 and 2007 is studied using the particle monitor of
the High Energy X-ray Timing Experiment on board NASA's Rossi X-ray Timing
Explorer. A special emphasis of this study is the location and strength of the
South Atlantic Anomaly (SAA). The size and strength of the SAA are
anti-correlated with the the 10.7 cm radio flux of the Sun, which leads the SAA
strength by ~1 year reflecting variations in solar heating of the upper
atmosphere. The location of the SAA is also found to drift westwards with an
average drift rate of about 0.3 deg/yr following the drift of the geomagnetic
field configuration. Superimposed to this drift rate are irregularities, where
the SAA suddenly moves eastwards and where furthermore the speed of the drift
changes. The most prominent of these irregularities is found in the second
quarter of 2003 and another event took place in 1999. We suggest that these
events are previously unrecognized manifestations of the geomagnetic jerks of
the Earth's magnetic field.Comment: 21 pages, 11 figures, accepted for publication in Earth and Planetary
Science Letter
Internet Privacy: Who Makes the Rules
Richard M. Smith, Chief Technology Officer of the Privacy Foundation, discusses the ways emerging technology infringes consumer privacy on the Internet. He believes the widespread use of cookies and the growing use of online profiling by companies like DoubleClick create serious privacy problems for people who use the Internet. The solution lies in combining the efforts of programmers, who can find ways to eliminate these profiling mechanisms online, and of lawyers, who can structure legal rules to proscribe information misuse
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