Sex-specific activity of (R)-(−)- and (S)- (+)-1,7-dioxaspiro[5.5]undecane,the major pheromone ofDacus oleae

1,7-Dioxaspiro[5.5]undecane (olean), the major component of the female sex attractant pheromone blend of the olive fruit flyDacus oleae (Gmelin) was shown to be released as a racemate. The response of males and females to pure (R)-(–) and (S)-(+)-enantiomers was tested under laboratory and field conditions. Males in laboratory and field tests responded only to (R)-(–)-olean, which functions as a sex attractant. Females responded only to (S)-(+)-olean in laboratory tests but not in the field. There are indications that the latter enantiomer fuctions as a short-range arrestant throughout the day and as an aphrodisiac in the process of mating.Diptera: Tephritidae.     

A Methodology for Transistor-Efficient Supergate Design

The number of transistors required for the implementation of a logic function is a fundamental consideration in digital VLSI design. While the determination of a series-parallel implementation can be straightforward once a simplified Boolean expression of the function is available, this may not be an optimum solution. In this paper, a methodology is developed for minimizing the number of transistors that starts from a sum-of-products expression and utilizes non-series-parallel structures. Experimental results demonstrate the efficiency of the approach     

Testable Designs of Multiple Precharged Domino Circuits

Domino CMOS circuits are an option for speeding up critical units. An inherent problem of Domino logic is that under specific input conditions the charge redistribution between parasitic capacitances at internal nodes of a circuit can violate the noise margins and cause erroneous responses at the output. The dominant solution to this problem is the multiple precharging of the gate's internal nodes. However, the added precharge transistors are not testable for stuck-open faults. Undetectable stuck-open faults at these transistors may cause noise margins reduction and consequently may affect the reliability of the circuit since its operation in the field will be sensitive to environmental factors such as noise. In this paper, we propose new multiple precharging design schemes that enhance Domino circuits' testability with respect to transistor stuck-open and stuck-on faults     

A Design Technique for Energy Reduction in NORA CMOS Logic

In this work, a design technique to reduce the energy consumption in NO RAce (NORA) circuits is presented. The technique is based on a unidirectional switch topology combined with a new clocking scheme permitting both charge recycling between circuit nodes and elimination of the short circuit current. Calculations proved that energy savings higher than 20% can be achieved. Simulation results from NORA designs in a 0.18-mum CMOS technology are presented to demonstrate the effectiveness of the proposed technique to achieve both energy and energy-delay product reduction     

Path delay fault testing of multiplexer-based shifters

In this paper we present a method for path delay fault testing of multiplexer-based shifters. We show that many paths of the shifter are not single path propagating hazard free robustly testable (SPP-HFRT) and we present a path selection method such that all the selected paths are SPP-HFRT by (Olog₂ n) test-vector pairs, where n is the length of the shifter's operand. The propagation delay along all other paths is a function of the delays along the selected paths. This is the first work addressing the problem of shifter path delay fault testing.     

A Circuit for Concurrent Detection of Soft and Timing Errors in Digital CMOS ICs

In this paper a new circuit for concurrent soft and timing error detection in CMOS ICs is presented. The circuit is based on current mode sense amplifier topologies to provide fast error detection times. After an error has been detected it can be corrected by using a retry cycle.     

Biological activity of chemicals identified from extracts and volatiles of maleRhagoletis cerasi

Fractions obtained by chromatographic separation of extracts and volatiles from maleRhagoletis cerasi flies were tested for biological activity on females under laboratory conditions. During the bioassays, the number of incoming flies as well as the time spent by individual flies on the area of stimulus were taken under consideration. Two distinct types of female behavior were observed, i.e., attraction and arrestant behavior. GC-MS analysis of biologically active fractions resulted in tentative identification of 75 compounds. EAG screening for 27 of these compounds was performed, and subsequent laboratory bioassays resulted in the confirmation of arrestant activity for various mixtures of eight fatty acids (octadecanoic, nonadecanoic, eicosatetraenoic, eicosapenaenoic, eicosaenoic, heneicosanoic, docosahexenoic, and docosanoic). Following EAG tests and laboratory bioassays, a possible mode of chemical communication of this species with sex pheromones is proposed.(Diptera: Tephritidae).     

Male olive fruit fly attraction to synthetic sex pheromone components in laboratory and field tests

Male olive fruit fly attraction to the four synthetic components of the female sex attractant pheromone was studied under laboratory and field conditions. In laboratory tests males responded to all four components tested separately. Component I, (1,7-dioxaspiro[5.5]undecane) was more attractive than any of the remaining three components alone, but a combination of all four was more attractive than component I alone. In field tests with polyethylene vials as pheromone dispensers, the complete mixture, although not statistically significant, was constantly more attractive to males than component I alone. A tendency of enhancement of attraction of component I by combining it with component II (-pinene) or III (n-nonanal) was also observed. In field tests with rubber septa as pheromone dispensers only component I was attractive. Mixtures containing component I were also attractive but not more attractive than component I alone. Evaporation rate and ratio of components as they come out of the dispenser appear to be critical for male response.     

1,5,7-Trioxaspiro[5.5]undecane,a pheromone analog with high biological activity for the olive fruit fly,Dacus oleae

l,5,7-Trioxaspiro[5.5]undecane, an analog of the major sex pheromone (olean) of the olive fruit fly, was synthesized via two different routes and tested for biological activity under laboratory and field conditions. In laboratory tests, its activity was comparable to that of olean, especially when a stabilizer or a high concentration was used. In field tests, its activity reached the level of olean only when a stabilizer and an open-type dispenser, which allows high rates of evaporation, were used. The residual activity of the analog dispensers did not exceed two weeks both under laboratory and field conditions compared to over four months for olean.     

A multicomponent female sex pheromone ofDacus oleae Gmelin: Isolation and bioassay

The sex attractant pheromone produced by femaleDacus oleae Gmelin is a mixture of four compounds, two of which are found in the rectal gland and the other two elsewhere in the insect body. The ratio of these compounds in the pheromone blend was measured. Biological activity of all four compounds and their combinations was studied in lab and field cage tests. The most abundant compound in the mixture (55.7%) shows the highest biological activity. Recombination of all compounds significantly increases activity of the main compound.Diptera: Tephritidae.This work was partly supported by NATO research grant No. 1352.