Current information technology relies on two independent processes: charge-based information processing (microprocessors) and spin-based data storage (magnetic hard drives). [1±5] The prospect of simultaneously manipulating both charge and spin in a single semiconductor medium is provided by the exciting area of spintronics. Among many others, diluted magnetic semiconductors (DMSs) represent the most promising candidates for such applications. [1±7] Herein we report on the magneto-and optoelectronic properties of single-crystalline diluted magnetic semiconductor nanowires Ga 1±x Mn x N (x = 0.01±0.09). These nanowires, which have diameters of 10±100 nm and lengths of up to tens of micrometers, exhibit ferromagnetism with Curie temperatures (T C s) above 300 K and magnetoresistances (MRs) up to 250 K. Spin-dependent electron transport from single-nanowire transistors indicates the homogeneous nature of the ferromagnetic nanowires.Gate-dependent conductance and electroluminescence (EL) from nanowire-based light-emitting-diode structures suggest their p-type characteristics, which might support the theory of hole-mediated ferromagnetism. These ferromagnetic GaN:Mn nanowires represent an important class of nanometer-scale building blocks for spintronics.Theoretical studies indicate that transition-metal-doped GaN possesses a ferromagnetic transition temperature higher than room temperature due to hole-mediated ferromagnetism, [8] which would be advantageous for many of the proposed spintronic applications. Many experiments have already been carried out to demonstrate such hypotheses, [9±11] although significant controversy exists over the possibility of magneticimpurity phase separation in many of these thin-film studies. [12±16] Moreover, intrinsic defects in these films originating from the molecular-beam epitaxial growth process may be the Achilles' heel in reaching a fundamental understanding of the ferromagnetism in these materials. On the other hand, the miniaturization of electronic devices represents an ongoing trend for both industrial manufacture and academic research. Among many other possibilities, nanotubes and nanowires are currently being actively explored as possible building blocks for electronic devices with features smaller than 100 nm. [17] The controlled fabrication and fundamental understanding of low-dimensional ferromagnetic semiconductor nanostructures is thus crucial to the development of semiconductorbased spintronic devices and spin-based quantum-computation schemes.Although progress has been made in the understanding of DMS quantum wells and dots, [1±7] studies of quantum wires are still at a nascent stage. Dimensionality and size are known to play a significant role in determining various properties of the systems. [17] In this regard, a one-dimensional (1D) DMS system at the nanometer scale, i.e., a DMS nanowire, is expected to have interesting magnetoelectronic properties and could be a good candidate for realizing spintronic devices for several reasons. First, nanowires themselve...

Introduction 318Cycles in relation to the moon 318Moon-related reproductive activity 319Reproductive season and lunar-related spawning rhythm of rabbitfishes 320Ovarian development and the lunar cycle 321Testicular development and lunar periodicity 323Environmental factors regulating lunar-related reproduction 324Closing remarks 325 Abstract Cues from the moon influence synchrony in growth, feeding, migration, behaviour and reproduction of many reef fishes. Compared with comprehensive studies on the annual and daily activities of fish, few physiological studies have paid attention to the importance of lunar cues in reproductive activities. We review mutual and interesting relationships between fish reproduction and environmental changes induced by the moon, with particular emphasis on the reproductive activity of the rabbitfishes (Siganidae). Rabbitfish species exhibit, in nature, a definitive reproductive season, which differs among the tropical areas. During the reproductive season, synchronous spawning of rabbitfish is associated with a particular lunar phase. The lunar phase used by the respective species is similar in different regions on the earth. Histological observations revealed that gonads develop synchronously towards a peak around the spawning lunar phase, after which the gonads return to spent condition. Concomitant with gonadal development, sex steroid hormones were produced under the influence of gonadotropin (GtH). Injections of human chronic gonadotropin (hCG) to the fish that are undergoing active spermatogenesis accelerated testicular maturation. These results suggest that hormonal response in maturing the gonads in rabbitfish is under the regulation of GtH, and that pituitary secretion of GtH according to the lunar cycle accounts for the lunar rhythm in gonadal development. We speculate that the cues from the moon can be recognized by the higher parts of the hypothalamus-pituitary-gonadal axis. Possible relationships between exogenous environmental factors and the lunar-reproductive rhythm are also discussed.

High quality, large grain size graphene on polycrystalline nickel film on two inch silicon wafers was successfully synthesized by the chemical vapor deposition (CVD) method. The polydimethylsiloxane (PDMS) stamping method was used for graphene transferring in this experiment. The graphene transferred onto Al2O3/ITO substrates was patterned into macroscopic dimension electrodes using conventional lithography followed by oxygen plasma etching. Experimental results show that this graphene can serve as transparent source and drain electrodes in high performance organic semiconductor nanoribbon organic field-effect transistors (OFETs), facilitating high hole injection efficiency due to the preferred work function match with the channel material: single crystalline copper phthalocyanine (CuPc) nanoribbons. The nanoribbons were grown on top of the patterned graphene via evaporate-deposition to form the FET device. The carrier mobility and on/off current ratio of such devices were measured to be as high as 0.36 cm2/(V s) and 10(4).

We have studied the in situ modification of coherently grown InGaAs dots by interaction with phosphorus. By monitoring the intensity of reflection high-energy electron diffraction transmission spot, the in situ phosphorus (precracked PH3) supply on the InGaAs dots was examined at 480 °C. It was found that the phosphorus exposure induces a surface structure change from a dot structure to a flat surface. The change is caused by the replacement of arsenic in the dots by phosphorus, which reduces the strain between the InGaAs(P) dots and the GaAs substrate. By switching AsH3/PH3 beams in situ, a reversible transition of the surface structure between the InGaAs dot structure and the InGaAsP flat surface was observed. A transitional state between the dot structure and the flat surface was metastabilized by tuning the AsH3/PH3 beam ratio. The metastabilized surface was observed ex situ using a high-resolution scanning electron microscope.

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