New PCR primer pairs specific for Cryptococcus neoformans serotype A or B prepared on the basis of random amplified polymorphic DNA fingerprint pattern analyses

The imprinting behavior of chicks was quantified as a preference score (correct response ratio) achieved in a running wheel apparatus. A total of 249 chicks were exposed to an imprinting stimulus and tested for stimulus-approaching behavior. The chicks were then classified as good learners (imprinted), poor learners (non-imprinted) and a gray-zone group, those were 46%, 31% and 23% of the total chicks respectively. Using the classified chicks, the acetylcholine (ACh) and glutamate releases from the medial hyperstriatum ventrale (MHV) of the chick forebrains were determined by in vivo microdialysis. The non-imprinted chicks were used as yoked controls. Increases of ACh and glutamate released were observed in the imprinted chicks during exposure to the imprinting stimulus, whereas there were no changes in the release of these neurotransmitters in the non-imprinted chicks during the imprinting exposure. These results might be indicated that cholinergic and glutamatergic synapses which are newly formed as functioning synapses with imprinting stimulus in the MHV are involved in the performance of imprinting behavior.     

Sexual selection by male choice in monogamous and polygynous human populations

The theoretical possibility of coevolution of a viability-reducing female physical trait and a male mating preference for that trait by Fisherian sexual selection in monogamous and polygynous populations is demonstrated using two-locus haploid models. It is assumed that there is dichotomous variation in male resources, resource-rich males have a wider choice among females than resource-poor males, and a female has greater reproductive success when mated with a resource-rich male than a resource-poor one. Under these assumptions, we find that sexual selection operates effectively when female reproductive success is strongly dependent on male resource, the proportion of females that mate with resource-rich males is neither small nor large, the degree of polygyny is low, and resources are inherited from father to son. We suggest that some human female physical traits may have evolved by sexual selection through male choice. The evolution of skin color by sexual selection is discussed as an example.     

Atomistic simulation of lattice defects in nano-scale semiconductors: minimal-basis TBMD method

The atomistic properties of lattice defects in the nano-scale semiconductor crystallites are studied using the improved nonorthogonal tight-binding molecular-dynamics (TBMD) method. This nonorthogonal TB theory, with only three adjustable parameters gives values of the energies and bonding distances which are in excellent agreement with the ab initio results for small semiconductor clusters. We apply this type of MD scheme for the calculations of lattice defects (dislocations) and γ-surface in the small semiconductor crystallites with the size of N  200. We have found that there are marked differences in the properties of lattice defects between those in the bulk and those in the nano-scale crystallites.     

Highly efficient cathodoluminescence from undoped ZnO nanophosphor

Abstract— Various ZnO morphologies with hexagonal cross sections were fabricated by using a thermal oxidation method. Comparison of the cathodoluminescence (CL) of synthesized ZnO to that of commercial ZnO:Zn phosphor revealed that strong green luminescence can be realized in undoped ZnO by using fabricated low‐dimensional nanostructures. The reasons for the enhancement in CL intensity are investigated in detail. Reabsorbed UV emission by the nanostructures themselves could be partly converted into green emission and therefore contributes to the enhancement of green emission. Moreover, whispering gallery resonance modes produced in the hexagonal microcavity were assumed to provide one of the qualitative explanations for the observation of enhanced green emission.     

Evaluation of the optical-coupling efficiency of InGaAlAs-InGaAsP butt joint using a novel multiple butt-jointed laser

We quantitatively estimated the optical-coupling efficiency at the InGaAlAs-InGaAsP butt-joint (BJ) part by fabricating a novel multiple-butt-jointed (MBJ) laser. The lasing characteristics of InGaAlAs-InGaAsP MBJ lasers formed by in situ cleaning process showed a high optical-coupling efficiency of approximately 98%, which is comparable to that of a conventional InGaAsP-InGaAsP MBJ lasers. Thus, high-quality BJ-based heterointegration of InGaAlAs and InGaAsP was successfully demonstrated.     

A study of switching techniques using serial and parallel resistors for power system stabilization

In recent years, electric power systems have become more and more complicated and large‐scale. As a result, transient stability problems and voltage problems in power systems are being taken more seriously. In this paper, switching techniques using serial and parallel resistors for power system stabilization are proposed, and computer simulations and experiments using a transmission simulator were performed. The effectiveness of the stabilization was shown because a system swing was damped off by the on–off control of the series and parallel resistors. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(2): 59–67, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10081     

PAF and PAF acetylhydrolase in the nervous system

PAF acetylhydrolase is a key enzyme of PAF inactivation. Intracellular PAF acetylhydrolase isoform Ib is a heterotrimeric enzyme composed of alpha-, beta- and gamma-subunits. The beta- and gamma-subunits act as a catalytic unit and their amino acid sequences are homologous. The alpha-subunit is not essential for catalytic activity but is a product of the causative gene for Miller-Dicker lissencephaly, suggesting this subunit plays an important role in brain development.     

Surface morphology for annealed and etched MgO(100)

Surface morphology dependence of MgO(100) on the variation of the annealing temperatures and times with the intermediate chemical etching are investigated by Auger electron spectroscopy (AES), atomic force microscopy (AFM) and reflection high energy electron diffraction (RHEED). AES spectra reveal that Ca segregates on the substrate surface in the higher temperature than 850 °C and this segregation can be completely removed by chemical etching with P₂O₅ + 2-propanol. The AFM observation clarifies that the different reconstruction of MgO(100) surface remarkably undergoes over 1000 °C.