Revealing hidden species distribution with pheromones: the case of Synanthedon vespiformis (Lepidoptera: Sesiidae) in Sweden

Synanthedon vespiformis L. (Lepidoptera: Sesiidae) is considered a rare insect in Sweden, discovered in 1860, with only a few observations recorded until a sex pheromone attractant became available recently. This study details a national survey conducted using pheromones as a sampling method for this species. Through pheromone trapping we captured 439 specimens in Southern Sweden at 77 sites, almost tripling the number of previously reported records for this species. The results suggest that S. vespiformis is truly a rare species with a genuinely scattered distribution, but can be locally abundant. Habitat analyses were conducted in order to test the relationship between habitat quality and the number of individuals caught. In Sweden, S. vespiformis is thought to be associated with oak hosts, but our attempts to predict its occurrence by the abundance of oaks yielded no significant relationships. We therefore suggest that sampling bias and limited knowledge on distribution may have led to the assumption that this species is primarily reliant on oaks in the northern part of its range, whereas it may in fact be polyphagous, similar to S. vespiformis found as an agricultural pest in Central and Southern Europe. We conclude that pheromones can massively enhance sampling potential for this and other rare lepidopteran species. Large-scale pheromone-based surveys provide a snapshot of true presences and absences across a considerable part of a species national distribution range, and thus for the first time provide a viable means of systematically assessing changes in distribution over time with high spatiotemporal resolution

New design method for low-cost TSC checkers for 1-out-of-n and (n - 1)-out-of-n codes in MOS implementation

A new method of designing totally self-checking (TSC) checkers for 1-out-of-n and (n — l)-out-of-n codes is presented. This method is well suited to VLSI MOS implementation, satisfying the current technological constraints. TSC checkers designed according to the proposed method offer significant economies in implementation cost over TSC checkers in the literature. © 1990 Taylor & Francis Ltd

Testable designs of one-count generators

Testable realizations of One-Count Generators (OCGs) with respect to an extended fault model, including the stuck-at, transistor stuck-open, and transistor stuck-on faults using current monitoring, are presented. These implementations are made up of testable components which are commonly found in current CMOS libraries. A new design method for OCGs is given which offers the ability to apply a desired robust pair of vectors at the inputs of every element of the OCG (and hence any desired single vector to them), as well as the ability to propagate the effect of any single fault to a primary output of the OCG. © 1998 Taylor and Francis Group, LLC

Device simulation of a n-DMOS cell with trench isolation

The DMOS cell, a high-voltage transistor, implemented in low voltage standard 0.18 mum double-well CMOS technology with trench isolation is studied. The operation of the cell is investigated with the use of a device simulator while the effect of the trench to the operation of the cell is revealed. (C) 2000 Elsevier Science Ltd. All rights reserved

A built-in I-DDQ testing circuit

Although I-DDQ testing has become a widely accepted defect detection technique for CMOS ICs, its effectiveness in very deep submicron technologies is threatened by the increased transistor leakage current. In this paper, a built-in IDDQ testing circuit is presented, that aims to extend the viability Of IDDQ testing in future technologies and first experimental results are discussed