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Biomedical subjects

M A Moussa

Publications and source records attributed to M A Moussa.

At least 91 records · Page 5Linked to original sources
PubMed1980

Topical mosquito repellents XIII: Cyclic analogs of lactic acid.

Numerous cyclic analogs of lactic acid were synthesized to ascertain whether they might act as agonists of antagonists of lactic acid, a known attractant for mosquitoes. These compounds were evaluated with an in vitro blood-feeding test system and an in vivo cloth test. Two of the compounds in the blood-feeding test system showed biphasic results, acting as attractants at low concentrations and as repellents at higher concentrations. Several compounds (III, V, VII, and X) repelled Aedes aegypti mosquitoes in the blood-feeding test system. However, in the in vivo cloth test system, only III repelled the mosquitoes significantly.

Aedes↗
PubMed1980

A program for discrimination based on continuous variables.

Given independent sets of observations from each of two multivariate normal distributions and common covariance matrix, the program estimates: (1) the discriminating power of each variate in terms of its error rate; (2) the linear discriminant function (LDF): coefficients, error rate, allocation rule and test of goodness; (3) the quadratic discriminant function: allocation rule on the assumption of heterogeneity of dispersion matrices.

Analysis of Variance↗
PubMed1980

Discrimination and allocation using a mixture of discrete and continuous variables with some empty states.

The likelihood ratio classification rule based on the location mode is estimated given: (1) data consist of both binary and continuous variables; (2) some states have either zero frequency or too few observations, the case that usually happens the practice. An iterative proportional fitting of convenient approximation of the log-linear models as well as a linear additive model are utilized in estimating the rule's parameters. Performance of the obtained rule is then assessed by estimated error rates.

Analysis of Variance↗
PubMed1980

A program for the analysis of incomplete two-way cross-classifications.

Given (1) the size (R X C) of an incomplete two-way contingency table, (2) the apriori cell probabilities, lambda ij, (i = 1, 2, ..., R; j =1, 2, ..., C), the program produces 5 arrays of smoothed cell counts after adjusting existing zeros to certain values according to lambda ij and a weighting factor, K, which is also computed together with the value of a risk function for each array. After selecting one of those arrays according to the value of the risk function, then the program produces estimates for parameters of the saturated, independence and other hierarchial log-linear models in addition to the likelihood ratio for testing their goodness of fit.

Computers↗
PubMed1979

Experimental plague in the California ground squirrel.

In experiments to determine the current susceptibility to plague, it was demonstrated that 256 Yersinia pestis (a local strain of high virulence) were required to produce a 50% infectious dose (ID50) in California ground squirrels (Spermophilus beecheyi) that had been collected in southeastern Monterey County, California; 6,070 Y. pestis were required to produce a 50% lethal dose (LD50). (The LD50 was about 24 times the ID50.) The frequency of serologic response to the specific fraction 1 antigen of Y. pestis and mortality were dose-related. Approximately half of the squirrels inoculated with six to 6,070 Y. pestis survived without seroconversion, whereas antibody to specific fraction 1 antigen was always observed in squirrels that survived challenges of greater than or equal to 60,700 Y. pestis. However, titers never exceeded 1:64. The implications of these data for enzootic and epizootic transmission of plague in resistant squirrel populations are examined.

Animals↗