17,528 research outputs found
Accuracy of the Ovulon Fertility Monitor to Predict and Detect Ovulation
The purpose of this pilot study was to correlate the three biologic markers of the Ovulon fertility monitor (a long-term predictive peak about 6 days before ovulation, a short-term predictive peak about 1 day before ovulation, and a nadir at the time of ovulation) with the peak in cervical mucus and the luteinizing hormone (LH) surge in the urine. Ten volunteer subjects (mean age 30.2 years) monitored their cervical-vaginal mucus, the surge of LH in the urine with a home assay test, and their vaginal electrical readings (with Ovulon monitors) on a daily basis for one to four menstrual cycles. In 19 of the 21 cycles that indicated a LH surge, there was a strong positive correlation between the LH surge and the peak of cervical-vaginal mucus (r = 0.96, P ≤ .01), and between the LH surge and both the Ovulon nadir and Ovulon short-term predictive peak (r = 0.84, P ≤ .01), and a modest positive correlation between the long-term Ovulon predictive peak and the LH surge (r = 0.62, P ≤ .01). The time of optimal fertility as determined by the peak in cervical mucus, the LH surge, and the Ovulon was similar. The Ovulon has potential as a reusable device to help women determine their fertile period
How Mexico's Dairy Industry Has Evolved Under the NAFTA - Implications for U.S. Dairy Exporters and U.S. Investors in Mexico's Dairy-Food Businesses
This Discussion Paper shows that the demand for imported dairy products will continue to be strong in Mexico, especially after the 2001-2002 recession ends. However, Mexico's dairy markets have matured under the NAFTA. As part of the maturity, a larger number of strong domestic firms have emerged and powerful European multi-nationals have increased dairy product sales in Mexico. In addition, the expansion of U.S. exports of fluid milk, yogurt, dried whey, and lactose to Mexico will be slow in near future because U.S. market shares of imports of these products are already large. Thus, Mexico's dairy markets no longer represent "low hanging fruit" (if they ever did) for U.S. dairy exporters and direct investorsNAFTA, Maturing Mexican Dairy Markets, U.S. Dairy Exports to Mexico, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, International Development, International Relations/Trade,
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The properties of Msh2-Msh6 ATP binding mutants suggest a signal amplification mechanism in DNA mismatch repair.
DNA mismatch repair (MMR) corrects mispaired DNA bases and small insertion/deletion loops generated by DNA replication errors. After binding a mispair, the eukaryotic mispair recognition complex Msh2-Msh6 binds ATP in both of its nucleotide-binding sites, which induces a conformational change resulting in the formation of an Msh2-Msh6 sliding clamp that releases from the mispair and slides freely along the DNA. However, the roles that Msh2-Msh6 sliding clamps play in MMR remain poorly understood. Here, using Saccharomyces cerevisiae, we created Msh2 and Msh6 Walker A nucleotide-binding site mutants that have defects in ATP binding in one or both nucleotide-binding sites of the Msh2-Msh6 heterodimer. We found that these mutations cause a complete MMR defect in vivo The mutant Msh2-Msh6 complexes exhibited normal mispair recognition and were proficient at recruiting the MMR endonuclease Mlh1-Pms1 to mispaired DNA. At physiological (2.5 mm) ATP concentration, the mutant complexes displayed modest partial defects in supporting MMR in reconstituted Mlh1-Pms1-independent and Mlh1-Pms1-dependent MMR reactions in vitro and in activation of the Mlh1-Pms1 endonuclease and showed a more severe defect at low (0.1 mm) ATP concentration. In contrast, five of the mutants were completely defective and one was mostly defective for sliding clamp formation at high and low ATP concentrations. These findings suggest that mispair-dependent sliding clamp formation triggers binding of additional Msh2-Msh6 complexes and that further recruitment of additional downstream MMR proteins is required for signal amplification of mispair binding during MMR
Explosive component acceptance tester using laser interferometer technology
Acceptance testing of explosive components requires a reliable and simple to use testing method that can discern less than optimal performance. For hot-wire detonators, traditional techniques use dent blocks or photographic diagnostic methods. More complicated approaches are avoided because of their inherent problems with setup and maintenance. A recently developed tester is based on using a laser interferometer to measure the velocity of flying plates accelerated by explosively actuated detonators. Unlike ordinary interferometers that monitor displacement of the test article, this device measures velocity directly and is commonly used with non-spectral surfaces. Most often referred to as the VISAR technique (Velocity Interferometer System for Any Reflecting Surface), it has become the most widely-accepted choice for accurate measurement of velocity in the range greater than 1 mm/micro-s. Traditional VISAR devices require extensive setup and adjustment and therefore are unacceptable in a production-testing environment. This paper describes a new VISAR approach which requires virtually no adjustments, yet provides data with accuracy comparable to the more complicated systems. The device, termed the Fixed-Cavity VISAR, is currently being developed to serve as a product verification tool for hot-wire detonators and slappers. An extensive data acquisition and analysis computer code was also created to automate the manipulation of raw data into final results
Volumetric measurement of tank volume
A method is disclosed for determining the volume of compressible gas in a system including incompressible substances in a zero-gravity environment consisting of measuring the change in pressure (delta P) for a known volume change rate (delta V/delta t) in the polytrophic region between isothermal and adiabatic conditions. The measurements are utilized in an idealized formula for determining the change in isothermal pressure (delta P sub iso) for the gas. From the isothermal pressure change (delta iso) the gas volume is obtained. The method is also applicable to determination of gas volume by utilizing work (W) in the compression process. In a passive system, the relationship of specific densities can be obtained
Food habits and dietary variability of pelagic nekton off Oregon and Washington, 1979-1984
The food habits of 20 species of pelagic nekton were investigated from collections made with small-mesh purse seines from 1979-84 off Washington and Oregon. Four species (spiny dogfish, Squalus acanthias; soupfin shark, Galeorhinus zyopterus; blue shark, Prionace glauca; and cutthroat trout, Salmo clarki) were mainly piscivorous. Six species (coho salmon, Oncorhynchus kisutch; chinook
salmon, O. tshawytscha; black rockfish, Sebastes melanops; yellowtail rockfish, S. f1avidus; sablefish, Anoplopoma fimbria; and jack mackerel, Trachurus symmetricus)
consumed both nektonic and planktonic organisms. The remaining species (market squid, Loligo opalescens; American shad, Alosa sapidissima; Pacific herring, Clupea harengus pallasi; northern anchovy, Engraulis mordax; pink
salmon, O. gorbuscha; surf smelt, Hypomesus pretiosus; Pacific hake, Merluccius productus; Pacific saury, Cololabis saira; Pacific mackerel, Scomber japonicus;
and medusafish, Icichthys lockingtom) were primarily planktonic feeders. There were substantial interannual, seasonal, and geographic variations in the diets of
several species due primarily to changes in prey availability. Juvenile salmonids were not commonly consumed by this assemblage of fishes (PDF file contains 36 pages.
Hunter Activities, Conflicts, and Opinions Following Implementation of a Controlled Waterfowl Hunting Program on the Rend Lake Public Hunting Area in 1995-96
Waterfowl Program Periodic Report no. 90Report issued on: 2 December 199
The Video Link Design Study
The video link concept is a proposed method for providing video codec service to the customer base in a manner similar to the way phone service is provided today. Three possible implementations are low volume solutions that could be used to test market the video link concepts. The third method, which is technically superior to the first two, would only be economically feasible in a high volume implementation
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