Receptor contributions to configural and elemental odor mixture perception.

Odor mixture perception can be configural (the mixture is qualitatively different from the components) or elemental (the components are recognizable). Some have argued that configural properties are dependent on chemical similarity and possible overlap at the receptor level. The authors show that a binary mixture in which both components activate the same receptor (17) has a configural odor, whereas a mixture that suppresses overlap has elemental odor properties. Rats trained to recognize mixtures of citronellal and octanal (strong 17 agonists) in many ratios rarely recognize the components, supporting configural representation of the odor mixture. However, when trained to recognize mixtures of citral (partial 17 agonist, inhibitor) and octanal, rats recognize 1 or both components over a wide range of ratios. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of mongoose odors on rat capture success

Wild rats,Rattus norvegicus, R. exulans, andR. rattus, avoided wire-cage live traps that had previously captured mongooses,Herpestes auropunctatus. Replacing traps soiled by mongooses with clean traps would increase rat capture success and reduce a source of experimental bias.     

Antennal olfactory responses of black turpentine beetle,Dendroctonus terebrans (Olivier), to bark beetle pheromones and host terpenes

Electroantennograms (EAGs) were recorded from male and female black turpentine beetles,Dendroctonus terebrans (Olivier), exposed to bark beetle pheromones and host terpenes. The dose-response curves indicated similarities in the receptor mechanisms for both sexes for each compound. Antennal sensitivity was greatest toendo-brevicomin, which correlates with the importance of the compound in the behavior of the beetles. At above-threshold concentrations, EAGs were greatest toendo-brevicomin and frontalin, suggesting a large population of antennal receptors for these compounds. A large population of receptors would be expected for compounds that play such a significant role in this beetle's behavior. Beetles were also shown to have receptors that respond to theIps pheromones, ipsenol, and ipsdienol.Research done in part while in the Department of Entomology, Texas Agricultural Experiment Station (TAES), Texas A&M University, and supported in part through McIntire-Stennis project 1525, USDA-CR Grant 85-CRCR-1-1856, and NATO Collaborative Research Grant 86-0710. All programs of the Agricultural Experiment Station are available without regard to race, ethnic origin, sex, or age. Virginia Polytechnic Institute and State University does not discriminate against employees, students, or applicants on the basis of race, sex, handicap, age, veteran status, national origin, religion or political affiliation.     

比率依赖 Holling-Ⅲ捕食-食饵系统的多个周期解

应用重合度定理研究一类比率依赖Holling-Ⅲ的捕食-食饵系统的周期解的存在性问题,建立了该系统具有至少一个正周期解的充分条件。     

固相微萃取气—质联用技术在饮用水气味分析中的应用

采用顶空－固相微萃取－气相色谱－质谱（ＨＳ－ＳＰＭＥ－ＧＣ／ＭＳ）法分析饮用水中的发霉气味，探讨１００ｕｍ聚二甲基硅氧烷（ＰＤＭＳ）纤维的采样条件和气－质联用仪的分析条件，结果表明：样品浓度、吸附和脱附时间、搅拌和加盐等因素均会影响分析结果，利用上述条件进行分析，得到较满意的分析结果。     

Poor diagnostic reliability, the Null-Bayes Logic Model, and their implications for sexually violent predator evaluations.

Forensic psychologists have approached sexually violent predator (SVP) civil commitment evaluations from the position that respondents must be positive for a condition from the Diagnostic and Statistical Manual of Mental Disorders (DSM) of the American Psychiatric Association to be classified as SVPs. The only research on DSM diagnostic reliability in SVP cases has been undertaken by J. S. Levenson (2004a) and R. L. Packard and J. Levenson (2006). Although Packard and Levenson claimed that diagnostic evaluations in SVP cases were highly reliable, a reanalysis of their data indicated otherwise. Further, high levels of diagnostic uncertainty were found for a proposed paraphilia referred to as paraphilia not otherwise specified-nonconsent. Diagnostic criteria used to identify paraphilias among SVP respondents are therefore characterized by poor reliability. Logic models that were previously used to determine diagnostic confidence are also obsolete. Recommendations for improving diagnostic reliability are discussed, and the Null-Bayes Logic Model (NBLM) is proposed as a method for reaching certainty opinions that is superior to past models based on unrestrained clinical judgment. The implications of the present results and the NBLM for future practice, research, and policy directions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chemically mediated associative learning: An important function in the foraging behavior ofMicroplitis croceipes (Cresson)

When experienced by contact with feces from hosts feeding on cowpeas, laboratory-reared females ofMicroplitis croceipes, a larval parasitoid ofHeliothis spp., orient and fly to odors of the same feces, whereas naive laboratory-reared females do not. Flight-tunnel studies revealed that associative learning occurs during female encounters with hosts and host products. When females antennate host feces, they learn to recognize the volatile odors associated with the feces. Females even can be conditioned to respond to novel and otherwise unattractive odors such as vanilla extract by exposure to these volatile substances in association with a water extract of the feces. They apparently link the volatile odors with a nonvolatile hostspecific recognition chemical found in the feces. The antennating stimulant, 13-methylhentriacontane, was found to be a valuable ingredient, apparently as a facilitator of the initial antennation and subsequent linkage of the volatiles to the nonvolatile host recognition cue.     

Insect predator-prey coevolution via enantiomeric specificity in a kairomone-pheromone system

Insect predators can be guided to their prey by a kairomonal response to the prey pheromone. We found this phenomenon to be highly specific in the bark beetle predatorThanasimus dubius. Olfactory responses and behavioral tests revealed that the predator is guided to its major preyDendroctonusfrontalis by the primary enantiomer of the pheromone of the prey, (1S, 5R)-(–)-frontalin. These and other findings suggest the co-evolution of a kairomone system of the predator and the pheromone system of its prey.Texas Agricultural Experiment Station paper No.TA17770. The work was funded in part by McIntire-Stennis project 1525 (TAES) and the USDA program entitled The Expanded Southern Pine Beetle Research and Applications Program through TAES-CSRS grant 680-15-10. The findings, opinions, and recommendations reported herein are those of the authors and not necessarily those of the United States Department of Agriculture.     

A Leslie–Gower-type predator–prey model with sigmoid functional response

In this work, a continuous-time predator–prey model of Leslie–Gower type considering a sigmoid functional response is analysed. Using the MatLab package some simulations of the dynamics are shown. Conditions for the existence of equilibrium points, their nature and the existence of at least one limit cycle in phase plane are established. The existence of a separatrix curve dividing the behaviour of trajectories is proved. Thus, two closed trajectories can have different ω-limits being highly sensitive to initial conditions. Moreover, for a subset of parameter values, it can be possible to prove that the point (0,0) can be globally asymptotically stable. So, both populations can go to extinction, but simulations show that this situation is very difficult. According to our knowledge no previous work exists analysing the model presented here. A comparison of the model here studied with the May–Holling–Tanner model shows a difference on the quantity of limit cycles.