Expression of natural killer receptor alleles at different Ly49 loci occurs independently and is regulated by major histocompatibility complex class I molecules.

Ly49 receptor genes are expressed by subsets of natural killer (NK) cells in an overlapping fashion, accounting for the capacity of NK subsets to attack host cells that have selectively downregulated self-major histocompatibility complex (MHC) class I molecules. It was shown previously that most NK cells express only one or the other allele of a given Ly49 gene, while a smaller population expresses both alleles. However, the methods used to detect monoallelic and biallelic cells were nonquantitative. Here, new allele-specific antibodies were used to provide the first quantitative examination of biallelic and monoallelic expression of Ly49A and Ly49G2. The results demonstrate conclusively that most Ly49A(+) and Ly49G2(+) NK cells express the corresponding gene in a monoallelic fashion, with a smaller subset expressing both alleles. Unexpectedly, biallelic Ly49A(+) NK cells were more numerous than predicted by completely independent allelic expression, suggesting some heterogeneity among NK progenitors in the potential to express a given Ly49 gene. The data also show that cells expressing one allele of Ly49G2 may express Ly49A from the same or opposite chromosome with equal likelihood, indicating that the expressed allele is chosen independently for different Ly49 genes. Finally, the data demonstrate that biallelic expression of Ly49A or Ly49G2 occurs least frequently in mice that express ligands for these receptors (H-2(d) mice), and most frequently in class I-deficient mice. Thus, biallelic expression of Ly49 genes is regulated by interactions of NK cell progenitors with MHC class I molecules

Relationships between selected characteristics of soybean producers and their management practices and participation in the extension program in Fayette County, Tennessee

The major purpose of this study was to determine the relationship between characteristics of soybean producers and their farming operation and their use of recommended management practices and their participation in the Extension Program. Fifty producers were randomly selected from the Fayette County Extension Service\u27s mailing list of all known soybean producers in the county. The nth number method of sampling was used to select the producers to be interviewed. An interview schedule was developed and the 50 producers were visited and personally interviewed by the researcher who was also the Assistant Extension Agent. All interviews were made from the period immediately following harvest in 1975 to April 1976. The data were coded and punched on computer cards and computations were made by the University of Tennessee Computer Center. The analysis of variance F test statistic was used to determine the association between each dependent variable and each of the qualitative independent variables. F values which achieved the .05 level of probability were accepted as being statistically significant. The Pearson Correlation Coefficient was used to determine the relationships between each dependent variable and each of the quantitative independent variables. Findings indicated that neither the producer\u27s major occupation nor his major source of income had significant influence upon the number of Extension contacts which he made. The number of contacts which the soybean producers had with Extension did not significantly influence the use of the nine recommended soybean production practices (i.e., prepared initial seedbed in fall or early spring, fertilized and limed according to soil test, planted soybeans between April 15 and June 15, planted a variety(s) recommended for 1975, used the recommended seeding rate, used inoculant on seeds on land where soybeans have not been grown in 3-5 years, treated seed with molybdenum when grown on soils with a pH of 6.5 or below or first year limestone was applied, used herbicides according to recommendations, harvested beans when the moisture was between 12 percent and 13.5 percent). Also, the number of contacts which the soybean producers made with Extension did not significantly influence their use of other soybean production and marketing practices. However, it was found that producers who frequently contacted the Extension Agents also contacted other available sources of information. There were definite correlations between size and Extension participation and age of producer and Extension participation. Those producers who farmed larger acreages made a significantly greater number of Extension contacts than the smaller producers. Also, as the producer\u27s age increased, the number of contacts he made with Extension decreased significantly

Friends, Neighbours and Distant Partners: Extending or Decentring Family Relationships?

[No abstract][No keywords]

How accurate is the use of ECGs in the diagnosis of myocardial infarct?

The electrocardiogram (ECG) is a fairly accurate test in the diagnosis of myocardial infarction (MI). However, given more sensitive technologies, such as cardiac biomarker testing, its primary role should be as an important adjunct in the evaluation and detection of MI (strength of recommendation [SOR]: A).The sensitivity of ECG for detection of MI is directly related to what is defined as positive findings on the ECG for MI. The single most specific ECG finding is the presence of new ST segment elevation of at least 1mm (SOR: A). Other findings such as the development of new pathologic Q waves and ST depression can also be valuable in making the diagnosis

A note on the calculation of the effective range

The closed form of the first order non-linear differential equation that is satisfied by the effective range within the variable phase formulation of scattering theory is discussed. It is shown that the conventional method of determining the effective range, by fitting a numerical solution of the Schr\"odinger equation to known asymptotic boundary conditions, can be modified to include the first order contribution of a long range interaction.Comment: 4 page

Recent Establishment of the Asian Tiger Mosquito (Aedes albopictus) in Independence County, Arkansas

Three adult Aedes albopictus were collected on 10 August 1993 within the city limits of Batesville, Arkansas. This is the firs tknown report of this species from Independence County. Subsequent investigation revealed the presence of at least three well established populations in the county, two of which were monitored on a monthly basis from Aprilto September of 1994. Peak A. albopictus numbers were recorded in July and August when the population levels were sufficient to make this mosquito a significant pest in Batesville. Our observations suggest that the Asian tiger mosquito will likely colonize other similar communities in Arkansas