Migration timing and distance from shore of southbound eastern Pacific gray whales (Eschrichtius robustus) off Ensenada,Baja California,Mexico

Eastern Pacific gray whales were monitored off Ensenada, Mexico, during the southbound migration. The objectives were to determine southbound migration timing and width of the migration corridor during three seasons (2003–2006). Migration timing was determined by fitting a generalized additive model to the shore counts for each season and estimating the 10, 50, and 90 percentiles of the fitted curves. To estimate abundance from shore‐based counts, a probability density function for the shore based distances was estimated by a product of a gamma distribution fit to the boat survey distance data for 2006/2007 and a half‐normal detection function using combined data of the three seasons. The parameters of the gamma distribution were corrected to account for less boat survey effort carried out 20–40 km than 0–20 km from shore. The onset of the migration off Ensenada was in late December/early January and ended around 13 February. The median date was 23–26 January for the first and third season and a week early for the second season. Boat surveys indicated a wide (20 km) migration corridor but most gray whales traveled within 9.9 km from shore. The estimated total number of whales during watch hours was 2,298 (95% CI = 1,536–4,447).     

Diploma Training for Technologists in Tissue Banking

There is a great demand for a formal training programme for tissue bank technologists not only for the Asia Pacific Region but also for technologists in other regions including Latin America and Africa. To meet this need, National University Hospital (NUH) Tissue Bank was established as the International Atomic Energy Agency (IAEA)/National University of Singapore (NUS) Regional Training Centre for training tissue bank operators in the Asia Pacific Region (Regional co-operative Agreement, RCA) in November 1997. The training centre conducts a one-year distance learning Diploma in Tissue Banking offered by the NUS. The syllabus for the Diploma Course included the multi-media IAEA curriculum on tissue banking. The first Diploma Course has been successfully completed in October 1998. Twelve students convocated, 4 with Distinction, 5 with Credit and 3 with Pass. Sixteen candidates from the Asia Pacific Region registered for the Second Diploma Course in April 1999. This second batch will be due to sit for their Diploma Examination in April 2000. With the increasing popularity of this Diploma Course, the third batch of students which will be registered in April 2000, will include technologists not only from Asia Pacific Region but also from other regions including Africa.     

Computer Dependence of An Improvement of The Cell Neighbour-Table Method For Short-Range Potentials

Abstract

A comparative test is presented for molecular dynamics, MD, computer simulation between the original Cell Neighbour-Table method, CNT, and a later development, the Link-Cell Neighbour-Table, LCNT. The test was simultaneously carried out on a vector Convex 210 computer and on a scalar Pentium 120. The comparison of the two methods for very large systems (up to 100000 particles) and for two short-range pair potentials (Weeks-Chandler-Andersen, WCA, and Lennard-Jones, LJ) showed that on the Convex, in vectorial mode, the LCNT method is about 25% more efficient in time than the CNT method for the shorter-range WCA potential, the difference being unnoticeable (less than 5%) for the LJ potential. However, when the scalar mode is on in the Convex, the difference disappears. In the Pentium, which was found to be systematically faster than the Convex even in vectorial mode, no significant difference of any kind between the both methods was found, with the either of the two potentials.     

Plant litter feedback and population dynamics in an annual plant,<Emphasis Type="Italic"> Cardamine pensylvanica</Emphasis>

The presence of litter has the potential to alter the population dynamics of plants. In this paper, we explore the effects of litter on population dynamics using a simple experimental laboratory system with populations of the annual crucifer, Cardamine pensylvanica. Using a factorial experiment with four densities and three litter levels, we determined the effect of litter on biomass and plant fecundity, and the life stages responsible for these changes in yield. Although litter had significant effects on seed germination and on seedling survivorship, we show, using a population dynamics model, that these effects were not demographically significant. Rather, the potential effect of litter on population dynamics resulted almost entirely from its effect on biomass. Persistent litter suppressed plant biomass and apparently removed the direct density effect present in the absence of litter. Thus, litter changed the shape of the recruitment curve from slightly humped to asymptotic. In addition to changing the shape of the recruitment curve, litter reduced the carrying capacity of the populations. Thus, the population dynamics model indicated that not all statistically significant responses were dynamically significant. Given the potential complexity of litter effects, simple population models provide a powerful tool for understanding the potential consequences of short-term responses. Received: 8 September 1999 / Accepted: 5 April 2000     

Genetic and evolutionary relationships among Asian Macaques

Published gene frequency data, checked for consistency of allele definitions across laboratories and for comparability of geographically identical samples, were pooled into a data set containing frequencies at nine loci for each of 20 populations that encompassed 10 macaque species. Genetic distances were calculated by the methods of Kidd and Cavalli-Sforza (1974). These distances were used to construct phylogenetic trees and to evaluate the relationships between divergence times and effective population sizes. Inter-and intraspecific genetic distances and the groupings defined by phenetic tree analyses support Fooden’s (1976) classification of the genus Macacainto four species groups. A paleozoogeographical model of Asia including the known times of major sea-level changes allows us to explain Macacainto four species groups. A paleozoogeographical model of Asia including the known times of major sea-level changes allows us to explain qualitatively the inferred evolutionary relationships among macaque species. Many assumptions are required in order to estimate the variables necessary in the quantitative prediction of genetic differences for a comparison between any two populations. Examination of those assumptions demonstrates the need for more accurate genetic as well as paleozoogeographic information. An erratum to this article is available at .     

Diagnostic Measures of Influence for s2

We present three intuitive diagnostic measures for judging the influence that single or multiple observations exert on the estimate s², the mean square error. The three measures are shown to be equivalent statistics. We discuss distributional properties of these measures and conclude with an example.