Optimal promising zone designs

Clinical trials with adaptive sample size reassessment based on an unblinded analysis of interim results are perhaps the most popular class of adaptive designs (see Elsäßer et al., 2007). Such trials are typically designed by prespecifying a zone for the interim test statistic, termed the promising zone, along with a decision rule for increasing the sample size within that zone. Mehta and Pocock (2011) provided some examples of promising zone designs and discussed several procedures for controlling their type‐1 error. They did not, however, address how to choose the promising zone or the corresponding sample size reassessment rule, and proposed instead that the operating characteristics of alternative promising zone designs could be compared by simulation. Jennison and Turnbull (2015) developed an approach based on maximizing expected utility whereby one could evaluate alternative promising zone designs relative to a gold‐standard optimal design. In this paper, we show how, by eliciting a few preferences from the trial sponsor, one can construct promising zone designs that are both intuitive and achieve the Jennison and Turnbull (2015) gold‐standard for optimality.     

The food and feeding ecology of Gerreidae, Bleeker 1859, in the estuaries of Natal

The food and feeding ecology of five species of Genes in the estuaries of Natal, were investigated from 1978 to 1980. The Kosi system, consisting of an estuary and three main lakes was selected as the main study area due to an abundance of Genes . Four other estuarine systems were sampled.
At Kosi polychaetes were important at the estuary, siphon tips (distal ±5 mm) of the bivalve Hiatula lunulata were most commonly taken in Lakes Makhawulani and Mpungwini, while chironomid larvae were important in Lake Nhlange. Ivlev's electivity test showed that Genes positively selected bivalve siphon tips when searching for food. The food taken by Genes from other estuaries was similar to that at Kosi, although the proportions of the different prey varied. At Kosi between three and five species occurred sympatri-cally. Resource segregation was through differences in diet and feeding periodicity and a superabundance of food ( H. lunulata siphon tips) during summer and autumn. During winter and spring when food may be limiting, most Genes leave shelf areas of the Kosi system, only G. acinaces remains in large numbers. Little is known of the diet of other fish which feed on benthic invertebrates in Kosi but there is probably little direct competition with Gerreidae, although Acanthopagrus berda and Pomadasys commersonni have been recorded feeding on the siphons of the bivalve Solen corneus , the former in Durban Bay and the latter at Kosi. In areas where the bivalve H. lunulata occurs it is suggested that Gerreidae have developed optimal foraging techniques which enhance resource partitioning.     

Convergence of Goals: Phylogenetical,Morphological, and Physiological Characterization of Tolerance to Drought Stress in Tall Fescue (Festuca arundinacea Schreb.)

The aim of this study is to find Iranian tall fescue accessions that tolerate drought stress and investigation on phylogenetical, morphological, and physiological characterization of them. For this propose, inter-simple sequence repeats (ISSR) markers were used to examine the genetic variability of accessions from different provinces of Iran. Of 21 primers, 20 primers generated highly reproducible fragments. Using these primers, 390 discernible DNA fragments were produced with 367 (93.95 %) being polymorphic. The polymorphic information content (PIC) values ranged from 0.948 to 0.976, with a mean PIC value of 0.969. Probability identity (PI) and discriminating power (D = 1 ? PI) among the primers ranged from 0.001 to 0.004 and 0.998 to 0.995, respectively. A binary qualitative data matrix was constructed. Data analyses were performed using the NTSYS software and the similarity values were used to generate a dendrogram via UPGMA. To study the drought stress, plants were irrigated at 25 % FC condition for three times. Fresh leaves were collected to measure physiological characters including: superoxide dismutase, catalase, and peroxidase activities and proline and total chlorophyll content at two times, before and after stress application. Relative water content, fresh and dry weight ratio, survival percentage, and visual quality were evaluated after stress. Morphological and physiological characters were assessed in order to classify accessions as either tolerant or sensitive using Ward’s method of Hierarchical cluster analysis in SPSS software. The results of present study demonstrated that the ISSR markers are useful for studying tall fescue genetic diversity. Convergence of morphological and physiological characterizations during drought stress and phylogenetic relationship results showed that accessions can be grouped into four clusters; drought-tolerant accessions that collected from west of Iran, drought-tolerant accessions collected from northwest of Iran, drought semi-tolerant accessions collected from center of Iran, and drought-sensitive accessions collected from north of Iran. Data presented could be used to classify the tall fescue accessions based on suitability of cultivation in the regions studied or the regions with the similar environmental condition.     

Development of the ovarian follicles in relation to changes in plasma parameters and 5 delta 3 beta HSD in snapping turtle, Chelydra serpentina

Follicular development in snapping turtle, Chelydra serpentina, was studied in relation to changes in plasma levels of estradiol-17 beta, total protein, calcium, inorganic phosphate and cholesterol. Histochemical reaction for 3 beta-HSD in granulosa and theca cells of the follicles is strong during the preovulatory and vitellogenic phases when the follicles attain their maximum size (18-22 mm) and estradiol is at a high level. The reaction for 3 beta-HSD is weal during the postovulatory phase when the developing follicles are at their minimum size (5-7 mm) and estradiol is low. Administration of estradiol-17 beta causes a rise in plasma calcium, total protein, inorganic phosphate and cholesterol.     

Name change for the Cambrian trilobite <Emphasis Type="Italic">Turkestanella</Emphasis> Repina, 1975

A replacement name, Irakimaspis nom. nov., is proposed for the mid-Cambrian redlichiide trilobite Turkestanella Repina, 1975. The name was preoccupied by the tentaculite Turkestanella Klishevich, 1969 (Dacrioconarida).     

Episodic events and estuaries: effects of cyclonic flushing on the benthic fauna and diet of Solea bleekeri (Teleostei) in Lake St Lucia on the south-eastern coast of Africa

The effects of an episodic event, involving the cyclonic flushing of, and associated rapid decrease in salinity in an estuarine system, on two faunal components was investigated. The rapid salinity decrease of some 25% had a direct, short-term effect on most components of the benthos of Lake St Lucia, as well as a long-term effect on the bivalves, particularly Solon cylindraceus , which species was unable to re-establish itself at previous densities. Indirect long-term effects were noted in the diet of Solea bleekeri , which feeds predominantly on the siphon tips of S. cylindraceus , in that it switched to feeding on whatever prey it could locate at the surface of the benthos. Although no change in densities of S. bleekeri was noted after the event, it is considered that the resultant change of diet did lead to some stress in the population. This study clearly demonstrates the need to monitor episodic events due to the direct and indirect effects, either short- or long-term, which they may have on the estuarine fauna.