Gamma radiation-induced nanodefects in diffusive memristors and artificial neurons.

Gamma photons with an average energy of 1.25 MeV are well-known to generate large amounts of defects in semiconductor electronic devices. Here we investigate the novel effect of gamma radiation on diffusive memristors based on metallic silver nanoparticles dispersed in a dielectric matrix of silica. Our experimental findings show that after exposure to radiation, the memristors and artificial neurons made of them demonstrate much better performance in terms of stable volatile resistive switching and higher spiking frequencies, respectively, compared to the pristine samples. At the same time we observe partial oxidation of silver and reduction of silicon within the switching silica layer. We propose nanoinclusions of reduced silicon distributed across the silica layer to be the backbone for metallic nanoparticles to form conductive filaments, as supported by our theoretical simulations of radiation-induced changes in the diffusion process. Our findings propose a new opportunity to engineer the required characteristics of diffusive memristors in order to emulate biological neurons and develop bio-inspired computational technology.

The ordered Heusler alloy Pd(2)MnIn investigated by photoelectron spectroscopy.

The full, ordered, antiferromagnetic Heusler alloy Pd(2)MnIn has been investigated using synchrotron radiation photoelectron spectroscopy. The Pd 4d Cooper minimum at 130 eV photon energy and the Mn 3p to 3d resonance at 49.5 eV photon energy have been used to determine the partial spectral weights of the Pd 4d and Mn 3d derived states. These partial spectral weights are consistent with published partial density of states calculated using the augmented spherical wave method. A quantitative fit of the resonant profile yielded an asymmetry parameter of 1.6 ± 0.4, indicating delocalization of the filled Mn 3d states.

X-ray observations of accreting white-dwarf systems.

Accretion in white-dwarf binary systems can occur through discs, accretion columns or a combination of these, depending on the magnetic field of the white dwarf. Recent high-quality X-ray observations with the XMM-Newton and Chandra observatories have significantly advanced our understanding of the physics of the accretion process, and place severe tests on our existing models. There have been some surprises, such as the strong dependence of atmospheric heating on accretion rate. However, we believe that we are now confident that we understand in general the physical processes in the accretion region, although some complicating factors, such as absorption, remain. We also discuss new developments in ultra-short-period white-dwarf binary systems.

IDEA: a large-scale project on electronic identification of livestock.

The aim of the IDEA (Identification électronique des animaux) project is to collect information on the feasibility of the introduction into the European Union (EU) of an animal electronic identification system, as referred to in Directive 92/102 and Regulation 1760/2000. The project will run for a period of four years (1998-2001) and will include one million animals in six countries (France, Germany, Italy, The Netherlands, Portugal and Spain). The Joint Research Centre, as technical co-ordinator of the project, provides technical support in terms of testing and certification of electronic identification devices, establishment of the central database, transmission and recording of data and evaluation of results. Identification has been undertaken in cattle, sheep, goats and buffalo using three types of electronic tags (ruminal bolus, ear tag and injectable transponder). The performance of these tags is checked at defined intervals until recovery in the slaughterhouse. The evaluation of the results in terms of the performance of the device and the necessary organisational support structures will lead to recommendations for a system to trace animals from birth to slaughterhouse, including the appropriate technology to be applied in any generalised system for the livestock sector in the EU.

A double-blind comparative study of alprazolam and dothiepin hydrochloride in the treatment of anxiety associated with depression.

One hundred patients with mixed symptoms of anxiety and depression were enrolled into a prospective, multi-centre, randomized, double-blind study comparing the response to, and the side-effects of, alprazolam and dothiepin hydrochloride over 4 weeks of treatment. Mean daily doses were 2.33 mg alprazolam and 115 mg dothiepin. Data on 96 patients were evaluated for tolerance, and data for 85 patients were analyzed for therapeutic response. In each case, the groups were similar in numbers, mean ages and sex ratios. Both groups experienced satisfactory responses to therapy, with highly statistically significant changes (p less than 0.001) in the means of all efficacy measures within each group. No statistical difference was demonstrated in favour of either treatment group. Both dothiepin and alprazolam exhibited a similar profile of mild minor side-effects, but more patients suffered moderate to severe reactions to dothiepin, leading to a greater drop-out rate in the dothiepin-treated group. It is concluded that, as both treatments produced equally satisfactory responses in this study, alprazolam should be considered for the treatment of anxiety associated with depression in patients for whom tricyclic antidepressant drugs are either contra-indicated or poorly tolerated.

Reproductive failure in swine associated with maternal seroconversion for porcine parvovirus.

Reproductive failure occurred in a swine herd in which the epizootiology of enteroviruses and the porcine parvovirus were being studied. Three virgin boars that were seropositive for the parvovirus were mated to seronegative, previously unmated gilts. The 11 gilts that farrowed had small litters, with high perinatal mortality. The remaining 12 gilts were marketed because of infertility, and the reproductive tracts were examined. Pathologic findings included early embryonal death attributed to viral infection. After the reproductive failure, all gifts and boars were seropositive for the parvovirus, suggesting that the reproductive failure was associated with a parvovirus infection.