(Z,Z)-5,27-Tritriacontadiene: Major sex pheromone ofDrosophila pallidosa (Diptera; Drosophilidae)

A crude cuticular extract from both sexes of 3660 fruit flies (Drosophila pallidosa) was subjected to SiO₂ and AgNO₃/SiO₂ column chromatography, accompanied by bioassay for the sex pheromone activity. After three chromatographic steps, the active fraction was obtained. The main component of the active fraction was determined to be (Z,Z)-5,27-tritriacontadiene [(Z,Z)-5,27-C_33:2, on the basis of gas-liquid chromatographic analysis, chemical derivatization and gas chromatography-mass spectrometry. Synthetic (Z,Z)-5,27-C_33:2 at 5 female equivalents (FE) elicited a clear courtship response with a high courtship index amongD. pallidosa males. Therefore it was concluded that (Z,Z)-5,27-C_33:2 was a major sex pheromone component in this species.     

Behavioral Response of Males to Major Sex Pheromone Component, (Z,Z)-5,25-Hentriacontadiene, of Drosophila ananassae Females

To identify sex pheromone components in Drosophila ananassae, the cuticular hydrocarbons were analyzed and bioassayed. After silicic acid and two silver nitrate–silicic acid chromatographic steps, active fractions containing (Z,Z)-5,25- and (Z,Z)-4,26-hentriacontadiene as the most abundant components were obtained. Both hydrocarbons could elicit male courtship behavior. The former was the more predominant compound and elicited a higher courtship index value than the latter. Cuticular hydrocarbon differences between D. ananassae and its close relative, D. pallidosa, and their roles in species recognition are discussed.     

Traveling bumps and their collisions in a two-dimensional neural field

A neural field is a continuous version of a neural network model accounting for dynamical pattern forming from populational firing activities in neural tissues. These patterns include standing bumps, moving bumps, traveling waves, target waves, breathers, and spiral waves, many of them observed in various brain areas. They can be categorized into two types: a wave-like activity spreading over the field and a particle-like localized activity. We show through numerical experiments that localized traveling excitation patterns (traveling bumps), which behave like particles, exist in a two-dimensional neural field with excitation and inhibition mechanisms. The traveling bumps do not require any geometric restriction (boundary) to prevent them from propagating away, a fact that might shed light on how neurons in the brain are functionally organized. Collisions of traveling bumps exhibit rich phenomena; they might reveal the manner of information processing in the cortex and be useful in various applications. The trajectories of traveling bumps can be controlled by external inputs.     

System theory for numerical analysis

Many numerical schemes can be suitably studied from a system theoretic point of view. This paper studies the relationship between the two disciplines, that is, numerical analysis and system theory. We first see that various iterative solution schemes for linear and nonlinear equations can be suitably transformed into the form of a closed-loop feedback system, and show the crucial role of the internal model principle in such a context. This leads to new stability criteria for Newton's method. We then study Runge-Kutta type methods for solving differential equations, and also derive new stability criteria based on recent results on LMI. A numerical example is given to illustrate the advantage of the present theory.     

Group impressions as dynamic configurations: The tensor product model of group impression formation and change.

Group impressions are dynamic configurations. The tensor product model (TPM), a connectionist model of memory and learning, is used to describe the process of group impression formation and change, emphasizing the structured and contextualized nature of group impressions and the dynamic evolution of group impressions over time. TPM is first shown to be consistent with algebraic models of social judgment (the weighted averaging model; N. Anderson, 1981) and exemplar-based social category learning (the context model; E. R. Smith & M. A. Zárate, 1992), providing a theoretical reduction of the algebraic models to the present connectionist framework. TPM is then shown to describe a common process that underlies both formation and change of group impressions despite the often-made assumption that they constitute different psychological processes. In particular, various time-dependent properties of both group impression formation (e.g., time variability, response dependency, and order effects in impression judgments) and change (e.g., stereotype change and group accentuation) are explained, demonstrating a hidden unity beneath the diverse array of empirical findings. Implications of the model for conceptualizing stereotype formation and change are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distributed parameter modeling and finite-frequency loop-shaping of electromagnetic molding machine

We derive a mathematical model for an electromagnet inside a molding machine, and propose a novel loop-shaping method of the proportional–integral (PI) controller design for the system based on the generalized KYP (GKYP) lemma. The behavior of the molding machine is difficult to capture by using finite-dimensional models owing to eddy currents spatially distributed throughout the electromagnet. To analyze fundamental properties of the system both theoretically and experimentally, we first derive a mathematical model of the machine in terms of a partial differential equation (PDE). An analysis using the PDE model shows that a low-dimensional approximation performed by standard spatial discretization results in a spillover effect, which makes the behavior of the closed-loop system oscillatory. Then, to develop an easily tunable and implementable control system, we propose a novel loop-shaping method for PI control on the basis of the GKYP lemma. In this control system design, we use multiple low-dimensional models, which work simultaneously in specified finite frequency ranges. The proposed method successfully suppresses the spillover effect despite the use of low-dimensional approximants. Finally, we show the efficiency of the proposed control design method through numerical and experimental verification and discuss a performance limitation of the PI control.     

Label-free electrochemical immunoassay for the detection of human chorionic gonadotropin hormone

Here we report on a new and rapid immunoassay for the label-free voltammetric detection of human chorionic gonadotropin hormone (hCG) in urine. Monitoring the changes in the current signals of antibodies (Abs) before and after the binding of the antigen (Ag) provides the basis for an immunoassay that is simple, rapid, and cost-effective. Since hCG is found at highly elevated levels in pregnant female urine with the range of 30,000-200,000 mIU/mL (approximately 30-200 nM) by 8-10 weeks into pregnancy, its label-free electrochemical detection was achieved by using our method. The coverage of the electrode surface with the Ab and the incubation time with the target Ag were optimized for the detection of hCG. The limit of detection of our method was calculated to be 15 pM (n = 3, approximately 15 mIU/mL) in synthetic hCG samples and 20 pM (n = 3, approximately 20 mIU/mL) in human urine. The electrochemical results for the detection of hCG in the urine samples were in agreement with the results obtained using a reference system, enzyme-linked immunosorbent assay. Further research about the intrinsic electroactivity of Abs and their target molecules would surely provide new and sensitive screening assays, as well as extensive data regarding their interaction mechanisms.     

On the Excess Oxygen in Four-Layered Rock-Salt-Type Units of Modulated Thermoelectric Bi-Sr-(Co,Rh)-O Compounds

Excess oxygen exists in four-layered rock-salt (RS)-type units of modulated misfit-layered Bi-Sr-(Co,Rh)-O compounds, which consist of interpenetrating CdI₂-type (Co,Rh)O₂ and distorted four-layered RS-type block subsystems, which have two b-axes, i.e., b ₁ and b ₂, respectively. From carefully determined chemical contents and misfit ratios, p = b ₁/b ₂, two structural characteristics are concluded, namely, intermixing metal ions in the RS-type layers and excess oxygen δ in, or in the vicinity of, them. The chemical formulae are proposed as [(Bi_1−x (Co,Rh) _x )₂(Sr_1−y Bi _y )₂O_4+δ ] _p (Co,Rh)O₂. The valence states of␣cobalt and rhodium ions are close to 3.3+. These valence states are quite reasonable for good thermoelectric oxides, such as γ-Na_0.7CoO₂ and [Ca₂CoO₃]_0.62CoO₂. Excess oxygen would cause the undulated atomic arrangement.