On the Use of the Upper Confidence Limit for the Variance from a Pilot Sample for Sample Size Determination

In a recent paper, Browne (1995) investigated the use of a pilot sample for sample size calculation. Monte Carlo simulations indicated that using a 100 · (1 — γ) per cent upper one-sided confidence limit on the population varíance σ² leads to a sample size that guarantees the planned power with a probability of at least 1 ? γ. The purpose of this paper is to get further insight into the results of Browne by analytical considerations. Furthermore, the expected power is investigated when applying the strategy and recommendations for the choice of the pilot sample size are given.     

Observations on the pyramidal tract of the slow loris

The pyramidal system of the slow loris was investigated physiologically and histologically. The cerebral response to medullary pyramid stimulation was mapped and found to distribute in two separate foci, rostral to the hand and foot somatosensory foci. The tract was found to contain about 204,000 fibers at the midolivary level on one side, with about 85% of the fibers less than 2 Μm and 1% greater than 4 Μm. Calculation of the amplitude and configuration of the true antidromic response, based on the histological findings, disagreed with the observed response. The latter was found to be analogous to the rwave of the American opossum, which appears to result from intracortical pyramidal tract collateral activation of the cerebral neurons. This response is not present in the macaque monkey.     

Phytol synthesis from geranylgeraniol in spinach chloroplasts

The reduction of /2-¹⁴C/-geranylgeranylpyrophosphate to phytylpyrophosphosphate is shown for the first time in chloroplasts. The esterification of exogenous /2-¹⁴C/-geranylgeranylpyrophosphate with endogenous chlorophyllide and the stepwise reduction of the pigment bound geranylgeraniol to phytol was also proved for spinach chloroplasts for the first time.     

On the intracellular site of biosynthesis of α-tocopherol in Hordeum vulgare

When barley seedlings were exposed to ¹⁴CO₂ for 1–3 hr, ¹⁴C was preferentially incorporated into plastoquinone, but only in low amounts i