Statistical Analysis of Sleep Spindle Occurrences

Spindles - a hallmark of stage II sleep - are a transient oscillatory phenomenon in the EEG believed to reflect thalamocortical activity contributing to unresponsiveness during sleep. Currently spindles are often classified into two classes: fast spindles, with a frequency of around 14 Hz, occurring in the centro-parietal region; and slow spindles, with a frequency of around 12 Hz, prevalent in the frontal region. Here we aim to establish whether the spindle generation process also exhibits spatial heterogeneity. Electroencephalographic recordings from 20 subjects were automatically scanned to detect spindles and the time occurrences of spindles were used for statistical analysis. Gamma distribution parameters were fit to each inter-spindle interval distribution, and a modified Wald-Wolfowitz lag-1 correlation test was applied. Results indicate that not all spindles are generated by the same statistical process, but this dissociation is not spindle-type specific. Although this dissociation is not topographically specific, a single generator for all spindle types appears unlikely.     

Reversible DIDS binding to Band 3 protein in human erythrocyte membranes

Reversible binding of DIDS [4,4'-diisothiocyanato-2,2'-stilbenedisulphonate] to Band 3 protein, the anion exchanger located in erythrocyte plasma membrane, was studied in human erythrocytes. For this purpose, the tritiated form of DIDS ([³H]DIDS) has been synthesized and the filtering technique has been used to follow the kinetics of DIDS binding to the sites on Band 3 protein. The obtained results showed monophasic kinetics both for dissociation and association of the 'DIDS-Band 3' complex at 0° C in the presence of 165 mM KCl outside the cell (pH 7.3). A pseudo-first order association rate constant k₊₁     

Evaluation of the water quality of future tributaries to the planned Dobczyce reservoir (Poland) using macroinvertebrates

The bottom fauna of 5 tributaries of the planned Dobczyce reservoir and the River Raba below the dam was investigated in the preimpoundment period (1983–84). The abundance of macrofauna varied between 46 taxa (Wolnica stream) and 66 taxa (Brzezówka stream). Each station showed individual taxa composition except for the RABA-u and RABA-d (84% similarity). On the basis of 7 different biological indices the stations were divided into 3 categories: unpolluted (Brzezówka), slightly polluted (Bulinka, Trzemésnia and both Raba stations), and moderately polluted (Wolnica). Most sensitive to chemical pollution was the BIOTIC-index. The combination of environmental variables was used to predict biological indices. The most significant relationship (P < 0.01, R ² = 0.71) was found between the BIOTIC-index and physico-chemical factors. Some problems in the application of indices (sampling, indicator organisms and interpretation of the results) are discussed and local adaptations of methods used are recommended.