Sediment sampling evaluated with a new weighting function and index of reliability

A distance weighted average and a reliability index for the areal mean was developed in the process of estimating quantity and distribution of a patchy and highly variable regionalized variable: the ephemeral fine sediment thickness of a shallow marine embayment. The distance weight is partly a function of the morphometry of the surroundings, i.e. lower weight is given to a nearby sampling point, at a given distance, when area-typical morphometric parameters suggest a higher bottom variability. After interpolation, the reliability of the areal mean is quantified. The index of reliability, thus defined, is a function of the overall sampling intensity and coverage of the area. It makes data comparable despite varying morphometry and survey regularity and completeness. It is an aid to a more effective sampling strategy. Sediment thickness maps, and the mean and reliability index, are presented from 14 different sampling surveys. Tests were made to examine the validity of the approach.     

Quantitative autoradiographic determination of angiotensin-converting enzyme binding in rat pituitary and adrenal glands with 125I-351A, a specific inhibitor

We describe a quantitative autoradiographic technique which allows measurement of angiotensin-I-converting enzyme [ACE] (kininase II, peptidyldipeptide hydrolase, EC 3.4.15.1) levels in discrete areas of pituitary and adrenal glands in individual animals. Tissue sections were incubated with 125I-351A, a specific ACE inhibitor, and results were obtained with computerized densitometry and comparison to 125I standards. There were high levels of ACE in both the anterior and posterior lobes of the pituitary, with no detectable binding in the intermediate lobe. The maximum binding capacity (Bmax) was 920 +/- 62 fmol/mg protein for the anterior pituitary and 1162 +/- 67 fmol/mg protein for posterior pituitary. The binding affinity constant (Ka) was 0.95 +/- 0.11 X 10(9) M-1 and 1.20 +/- 0.19 X 10(9) M-1 for the anterior and posterior lobes, respectively. In the adrenal gland, there were two distinct areas of specific binding, the adrenal medulla and the adrenal capsule-zona glomerulosa area. The Bmax for the adrenal medulla was 652 +/- 80 fmol/mg protein and 294 +/- 53 fmol/mg protein for the adrenal capsule-zona glomerulosa. The Ka for 351A was 1.04 +/- 0.19 X 10(9) M-1 and 1.74 +/- 0.40 X 10(9) M-1 for medulla and adrenal capsule-zona glomerulosa respectively. The results support the existence of local ANG systems active in both the pituitary and adrenal glands.     

On the two-locus sampling distribution

Two methods are discussed for evaluating the distribution of the configuration of unlabeled gametic types in a random sample of size n from the two-locus infinitely-many-neutral-alleles diffusion model at stationarity. Both involve finding systems of linear equations satisfied by the desired probabilities. The first approach, which is due to Golding, is to include additional probabilities in the system that allow some members of the sample to be specified at only one locus. The second approach, which is new, considers the joint distribution of the sample configuration and the number of recombination events since the time of the most recent common ancestor. The first approach is used for numerical computation, whereas the second approach is used to derive a two-locus version of Hoppe's urn model. The latter permits efficient simulation of the two-locus sampling distribution, provided the recombination parameter is not too large.Supported in part by NSF grants DMS-8704369 and DMS-8902991     

On the Estimation of Population Mean in Stratified Sampling

When stratified random sampling is used for the estimation of population mean, use of ‘Combined ratio estimator’ is well known. Some improved estimators for population mean are proposed which are better than ‘Combined ratio estimator’ and some other well known existing ones, from the point of view of bias and mean square error. An empirical illustration is given.     

Airborne pollen in Kiev (Ukraine): gravimetric sampling

This article presents the results of aeropalynological observations in Kiev, carried out with a gravimetric method, during January–October, 1994. The six most abundant pollen types were: Betulaceae (21%), Chenopodiaceae/Amaranthaceae (10%), Ambrosia (10%), Artemisia (9%) Pinaceae (8%) and Poaceae (6%). Seasonal fluctuations of the atmospheric presence of tree/shrub and herb/grass pollen during the period March–September, 1993 and 1994, are also shown.     

Rapid sampling devices for metabolic engineering applications

A number of rapid sampling devices for metabolic engineering applications have been developed over the last years with the purpose of the estimation of in vivo metabolic concentrations and dynamics. This review outlines the designs and characteristics as well as the developments and changes in diverse approaches over the years. Primary performance parameters for these constructions are sampling time and rate and, for an accurate representation of the in vivo condition in cells, the reproducibility of results and easy handling throughout the sampling operation.