Current-induced two-level fluctuations in pseudo spin-valves (Co/Cu/Co) nanostructures

Two-level fluctuations of the magnetization state of pseudo spin-valve pillars Co(10 nm)/Cu(10 nm)/Co(30 nm) embedded in electrodeposited nanowires (~40 nm in diameter, 6000 nm in length) are triggered by spin-polarized currents of 10^7 A/cm^2 at room temperature. The statistical properties of the residence times in the parallel and antiparallel magnetization states reveal two effects with qualitatively different dependences on current intensity. The current appears to have the effect of a field determined as the bias field required to equalize these times. The bias field changes sign when the current polarity is reversed. At this field, the effect of a current density of 10^7 A/cm^2 is to lower the mean time for switching down to the microsecond range. This effect is independent of the sign of the current and is interpreted in terms of an effective temperature for the magnetization.Comment: 4 pages, 5 figures, revised version, to be published in Phys. Rev. Let

Outsourcing of the New Wave Form Acquisition, Surveillance and Diagnostic System for the LEP Injection Kickers

In 1996, a project has been launched to improve the acquisition, surveillance and diagnostic system of the LEP injection kickers. The technical solution is formed by a VXI acquisition hardware and a Windows NT / LabVIEW software environment. The realisation has been entirely outsourced to industry. This paper discusses the different phases of the project, from market survey over technical specification to acceptance tests, explains the technical choices and evaluates the results, presents the point of view of both parties on the collaboration and concludes with the experiences learned from this project

Vascular hamartoma in the distal region of the anterior face of the left forearm, a rare lesion: a case report

The word hamartoma is derived from the Greek word hamartia meaning "to err" or "to blame", with the addition of "-oma" denoting a tumor-like growth. Hamartomas are non-malignant tissue malformations characterized by defective dissemination of fully differentiated cells and soft tissue native to the affected organ. If the tissues involved are composed of blood vessels, they are called vascular hamartomas. In our manuscript we describe the case of a 16-year-old adolescent with the presence of a tumor in the distal region, anterior face of the left forearm, who underwent an excisional biopsy with histopathological report of vascular hamartoma, currently with adequate postoperative evolution. The most commonly reported site of occurrence of vascular hamartomas is on the face and they are generally asymptomatic and silent at different stages of life. The definitive diagnosis for this type of pathology is by histopathology. Vascular hamartomas are a rarely reported benign pathology, due to their low incidence, this can make timely diagnosis difficult, as well as the ideal treatment for these patients

Naïve orangutans (Pongo abeliiand Pongo pygmaeus) individually acquire nut‐cracking using hammer tools

Nut-cracking with hammer tools (henceforth: nut-cracking) has been argued to be one of the most complex tool-use behaviors observed in nonhuman animals. So far, only chimpanzees, capuchins, and macaques have been observed using tools to crack nuts in the wild (Boesch and Boesch, 1990; Gumert et al., 2009; Mannu and Ottoni, 2009). However, the learning mechanisms behind this behavior, and the extent of nut-cracking in other primate species are still unknown. The aim of this study was two-fold. First, we investigated whether another great ape species would develop nut-cracking when provided with all the tools and appropriate conditions to do so. Second, we examined the mechanisms behind the emergence of nut-cracking by testing a naïve sample. Orangutans (Pongo abelii and Pongo pygmaeus) have the second most extensive tool-use repertoire among the great apes (after chimpanzees) and show flexible problem-solving capacities. Orangutans have not been observed cracking nuts in the wild, however, perhaps because their arboreal habits provide limited opportunities for nut-cracking. Therefore, orangutans are a valid candidate species for the investigation of the development of this behavior. Four nut-cracking-naïve orangutans at Leipzig zoo (P. abelii; Mage = 16; age range = 10–19; 4F; at the time of testing) were provided with nuts and hammers but were not demonstrated the nut-cracking behavioral form. Additionally, we report data from a previously unpublished study by one of the authors (Martina Funk) with eight orangutans housed at Zürich zoo (six P. abelii and two P. pygmaeus; Mage = 14; age range = 2–30; 5F; at the time of testing) that followed a similar testing paradigm. Out of the twelve orangutans tested, at least four individuals, one from Leipzig (P. abelii) and three from Zürich (P. abelii and P. pygmaeus), spontaneously expressed nut-cracking using wooden hammers. These results demonstrate that nut-cracking can emerge in orangutans through individual learning and certain types of non-copying social learning