Influence of external magnetic fields on growth of alloy nanoclusters

Kinetic Monte Carlo simulations are performed to study the influence of external magnetic fields on the growth of magnetic fcc binary alloy nanoclusters with perpendicular magnetic anisotropy. The underlying kinetic model is designed to describe essential structural and magnetic properties of CoPt_3-type clusters grown on a weakly interacting substrate through molecular beam epitaxy. The results suggest that perpendicular magnetic anisotropy can be enhanced when the field is applied during growth. For equilibrium bulk systems a significant shift of the onset temperature for L1_2 ordering is found, in agreement with predictions from Landau theory. Stronger field induced effects can be expected for magnetic fcc-alloys undergoing L1_0 ordering.Comment: 10 pages, 3 figure

EEG microstate architecture does not change during passive whole-body accelerations

Background and aim!#!The extent of penumbra tissue and outcome in stroke patients depend on the collateral cranial vasculature. To provide optimal individualized care for stroke patients in the emergency room setting we investigated the predictive capability of a stringent evaluation of the collateral vessels in ischemic stroke on clinical outcome and infarct size.!##!Methods!#!We retrospectively studied uniform clinical and radiological data of 686 consecutive patients admitted to the emergency department with suspected acute ischemic stroke. Cranial collateral vasculature status was graded using the initial CT-angiography. Outcome was measured by mRS, NIHSS and final infarct size at hospital discharge. All data were used to build a linear regression model to predict the patients´ outcome.!##!Results!#!Univariate and multivariate analyses showed significant effects of the whole brain collateral vessel score on all outcome variables. Atherosclerosis and piale collateral status were associated with the final infarct volume (FIV). Atherosclerosis and age were associated with the NIHSS at discharge. The presence of atherosclerosis, glucose level on admission and age were associated with the mRS at discharge. The multivariate models were able to predict 29% of the variance of the mRS at discharge, 24% of the variance in FIV and 17% of the variance of the NIHSS at discharge. The whole brain collateral status and the presence of atherosclerosis were the most relevant predictors for the clinical and radiological outcome.!##!Conclusion!#!The whole brain collateral vasculature status is clearly associated with clinical and radiological outcome but in a multivariate model seems not sufficiently predictive for FIV, mRS and NIHSS outcome at discharge in non-preselected patients admitted to the emergency department with ischemic stroke

High-resolution profiling of protein occupancy on polyadenylated RNA transcripts

A key prerequisite to understand how gene regulatory processes are controlled by the interplay of RNA-binding proteins (RBPs) and ribonucleoprotein complexes with RNAs is the generation of comprehensive high-resolution maps of protein-RNA interactions. Recent advances in next-generation sequencing technology accelerated the development of various crosslinking and immunoprecipitation (CLIP) approaches to broadly identify RNA regions contacted by RNA-binding proteins. However these methods only consider single RNA-binding proteins and their contact sites, irrespective of the overall cis-regulatory sequence space contacted by other RNA interacting factors. Here we describe the application of protein occupancy profiling, a novel approach that globally displays the RNA contact sites of the poly(A)+ RNA-bound proteome. Protein occupancy profiling enables the generation of transcriptome-wide maps of protein-RNA interactions on polyadenylated transcripts and narrows the sequence search space for transcript regions involved in cis-regulation of gene expression in response to internal or external stimuli, altered cellular programs or disease

Translocation of reindeer from South Georgia to the Falkland Islands

This report describes the first translocation of reindeer Rangifer tarandus from South Georgia to the Falkland Islands, in the South Atlantic Ocean. Reindeer were introduced from Norway to the subantarctic island of South Georgia on three occasions in the early 1900s by Norwegian whalers, and today they exist as two discrete herds, numbering approximately 2600 individuals in total. Because of concerns over the impact on native vegetation, the long-term eradication of reindeer from South Georgia has recently been proposed. A translocation of reindeer to the Falkland Islands was undertaken in 2001 by the Falkland Island Government with two objectives: (1) to preserve the genetic resources of at least one of the South Georgia herds; and (2) to facilitate the diversification of the agricultural sector of the Falkland Islands by establishing a commercial reindeer herd. Techniques developed and used in North America for the successful relocation of large numbers of calves were adopted for the translocation. A total of 59 calves (26 females and 33 males) were successfully translocated from South Georgia to the Falklands Islands in 2001, and subsequently produced their first offspring in 2003. Good husbandry practices and an understanding of biology and behaviour are essential for the successful translocation of reindeer.Flytting av rein fra Sør-Georgia til FalklandsøyeneAbstract in Norwegian / Sammendrag: Artikkelen beskriver den første overføring av rein Rangifer tarandus fra Sør-Georgia til Falklandsøyene i søratlanteren. Tamrein fra Norge ble flyttet til den subarktiske øya Sør-Georgia ved tre anledninger i perioden 1911 til 1925 i forbindelse med den norske hvalfangsten der. I dag består bestanden av rundt regnet 2600 dyr fordelt på to geografisk atskilte flokker. Av hensyn til den naturlige vegetasjonen på øya er det forslag om å på sikt utrydde reinbestanden på øya. Regjeringen på Falklandsøyene foretok en første overføring av rein fra Sør-Georgia i 2001 ut fra en målsetting om å 1) bevare genetiske ressurser fra minst en av de to reinflokkene, og 2) øke mulighetene innenfor landbrukssektoren på Falklandsøyene ved å etablere en kommersiell reinflokk der. Overføringen ble utført med metoder som hadde vist seg formålstjenlige ved flytting og nylokalisering av kalver i Nord-Amerika. Totalt ble 59 kalver overført i 2001 derav 26 hunndyr. De overførte reinene produserte kalver i 2003. God driftspraksis og biologisk og atferdsmessig forståelse var viktig for en vellykket overføring

Developments in CORG: a gene-centric comparative genomics resource

The CORG resource (Comparative Regulatory Genomics, ) provides extensive cross-species comparisons of promoter regions in particular and whole gene loci in general. Pairwise as well as multiple alignments of 10 vertebrate species form the key component of CORG. We implemented a rapid alignment approach based on weight matrix motif anchors to ensure efficient computation and biologically informative alignments. All CORG workbench components have been enhanced towards more flexibility and interactivity. Reference sequence based data presentation and analysis was put into the well-known and modular Generic Genome Browser framework. Herein, various plugins facilitate online data analysis and integration with static conservation data. Main emphasis was put on the design of a new JAVA WebStart application for comparative data display. Flexible data import and export options for standard formats complete the provided services

Monte Carlo Study of Ordering and Domain Growth in a Class of fcc-Alloy Models

Ordering processes in fcc-alloys with composition A_3B (like Cu_3Au, Cu_3Pd, CoPt_3 etc.) are investigated by Monte Carlo simulation within a class of lattice models based on nearest-neighbor (NN) and second-neighbor (NNN) interactions. Using an atom-vacancy exchange algorithm, we study the growth of ordered domains following a temperature quench below the ordering spinodal. For zero NNN-interactions we observe an anomalously slow growth of the domain size L(t) \sim t^\alpha, where \alpha \sim 1/4 within our accessible timescales. With increasing NNN-interactions domain growth becomes faster and \alpha gradually approaches the value 1/2 as predicted by the conventional Lifshitz-Allen-Cahn theory.Comment: 6 pages, 4 figure

Acoustic radiation controls friction: Evidence from a spring-block experiment

Brittle failures of materials and earthquakes generate acoustic/seismic waves which lead to radiation damping feedbacks that should be introduced in the dynamical equations of crack motion. We present direct experimental evidence of the importance of this feedback on the acoustic noise spectrum of well-controlled spring-block sliding experiments performed on a variety of smooth surfaces. The full noise spectrum is quantitatively explained by a simple noisy harmonic oscillator equation with a radiation damping force proportional to the derivative of the acceleration, added to a standard viscous term.Comment: 4 pages including 3 figures. Replaced with version accepted in PR

Kinetics in one-dimensional lattice gas and Ising models from time-dependent density functional theory

Time-dependent density functional theory, proposed recently in the context of atomic diffusion and non-equilibrium processes in solids, is tested against Monte Carlo simulation. In order to assess the basic approximation of that theory, the representation of non-equilibrium states by a local equilibrium distribution function, we focus on one-dimensional lattice models, where all equilibrium properties can be worked exactly from the known free energy as a functional of the density. This functional determines the thermodynamic driving forces away from equilibrium. In our studies of the interfacial kinetics of atomic hopping and spin relaxation, we find excellent agreement with simulations, suggesting that the method is useful also for treating more complex problems.Comment: 8 pages, 5 figures, submitted to Phys. Rev.