Low-field microwave absorption in epitaxial La-Sr-Mn-O films resulting from the angle-tuned ferromagnetic resonance in the multidomain state

We studied magnetic-field induced microwave absorption in 100-200 nm thick La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ films on SrTiO$_{3}$ substrate and found a low-field absorption with a very peculiar angular dependence: it appears only in the oblique field and is absent both in the parallel and in the perpendicular orientations. We demonstrate that this low-field absorption results from the ferromagnetic resonance in the multidomain state (domain-mode resonance). Its unusual angular dependence arises from the interplay between the parallel component of the magnetic field that drives the film into multidomain state and the perpendicular field component that controls the domain width through its effect on domain wall energy. The low-field microwave absorption in the multidomain state can be a tool to probe domain structure in magnetic films with in-plane magnetization.Comment: 9 pages, 9 Figure

BaCu3O4: High Temperature Magnetic Order in One-Dimensional S=1/2 Diamond-Chains

The magnetic properties of the alkaline earth oxocuprate BaCu3O4 are investigated. We show that the characteristic Cu3O4 layers of this material can be described with diamond chains of antiferromagnetically coupled Cu 1/2 spins with only a weak coupling between two adjacent chains. These Cu3O4 layers seem to represent a so far unique system of weakly coupled one-dimensional magnetic objects where the local AF ordering of the Cu2+ ions leads to an actual net magnetic moment of an isolated diamond chain. We demonstrate a magnetic transition at a high N\'eel temperature T_{N}=336 K

Spin wave resonances in La_{0.7}Sr_{0.3}MnO_{3} films: measurement of spin wave stiffness and anisotropy field

We studied magnetic field dependent microwave absorption in epitaxial La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ films using an X-band Bruker ESR spectrometer. By analyzing angular and temperature dependence of the ferromagnetic and spin-wave resonances we determine spin-wave stiffness and anisotropy field. The spin-wave stiffness as found from the spectrum of the standing spin-wave resonances in thin films is in fair agreement with the results of inelastic neutron scattering studies on a single crystal of the same composition [Vasiliu-Doloc et al., J. Appl. Phys. \textbf{83}, 7343 (1998)].Comment: 15 pages, 7 figures (now figure captions are included

Nonresonant microwave absorption in epitaxial La-Sr-Mn-O films and its relation to colossal magnetoresistance

We study magnetic-field-dependent nonresonant microwave absorption and dispersion in thin La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ films and show that it originates from the colossal magnetoresistance. We develop the model for magnetoresistance of a thin ferromagnetic film in oblique magnetic field. The model accounts fairly well for our experimental findings, as well as for results of other researchers. We demonstrate that nonresonant microwave absorption is a powerful technique that allows contactless measurement of magnetic properties of thin films, including magnetoresistance, anisotropy field and coercive field.Comment: 20 pages, 11 figure

Draft Genome Sequence of the Principal Etiological Agent of Farmer?s Lung Disease, Saccharopolyspora rectivirgula

Saccharopolyspora rectivirgula is the main cause of farmer's lung disease. The development of recombinant antigens to standardize the serodiagnosis of the disease requires knowledge of the S. rectivirgula genome. We sequenced the genome of an environmental strain, S. rectivirgula DSM 43113. A total of 3,221 proteins were found to be encoded in a short 3.9-Mb genome

Statistical inference of the generation probability of T-cell receptors from sequence repertoires

Stochastic rearrangement of germline DNA by VDJ recombination is at the origin of immune system diversity. This process is implemented via a series of stochastic molecular events involving gene choices and random nucleotide insertions between, and deletions from, genes. We use large sequence repertoires of the variable CDR3 region of human CD4+ T-cell receptor beta chains to infer the statistical properties of these basic biochemical events. Since any given CDR3 sequence can be produced in multiple ways, the probability distribution of hidden recombination events cannot be inferred directly from the observed sequences; we therefore develop a maximum likelihood inference method to achieve this end. To separate the properties of the molecular rearrangement mechanism from the effects of selection, we focus on non-productive CDR3 sequences in T-cell DNA. We infer the joint distribution of the various generative events that occur when a new T-cell receptor gene is created. We find a rich picture of correlation (and absence thereof), providing insight into the molecular mechanisms involved. The generative event statistics are consistent between individuals, suggesting a universal biochemical process. Our distribution predicts the generation probability of any specific CDR3 sequence by the primitive recombination process, allowing us to quantify the potential diversity of the T-cell repertoire and to understand why some sequences are shared between individuals. We argue that the use of formal statistical inference methods, of the kind presented in this paper, will be essential for quantitative understanding of the generation and evolution of diversity in the adaptive immune system.Comment: 20 pages, including Appendi

A Marriage of Old and New: Chemostats and Microarrays Identify a New Model System for Ammonium Toxicity

Toxicity is related to an organism's ability to rid itself of the offending molecules. This primer provides insights into how this can be monitored by highlighting the case of ammonium toxicity

Performance of a brief geriatric evaluation compared to a comprehensive geriatric assessment for detection of geriatric syndromes in family medicine: a prospective diagnostic study.

Geriatric syndromes are rarely detected in family medicine. Within the AGE program (active geriatric evaluation), a brief assessment tool (BAT) designed for family physicians (FP) was developed and its diagnostic performance estimated by comparison to a comprehensive geriatric assessment. This prospective diagnostic study was conducted in four primary care sites in Switzerland. Participants were aged at least 70 years and attending a routine appointment with their physician, without previous documented geriatric assessment. Participants were assessed by their family physicians using the BAT, and by a geriatriciant who performed a comprehensive geriatric assessment within the following two-month period (reference standard). Both the BAT and the full assessment targeted eight geriatric syndromes: cognitive impairment, mood impairment, urinary incontinence, visual impairment, hearing loss, undernutrition, osteoporosis and gait and balance impairment. Diagnostic accuracy of the BAT was estimated in terms of sensitivity, specificity, and predictive values; secondary outcomes were measures of feasibility, in terms of added consultation time and comprehensiveness in applying the BAT items. Prevalence of the geriatric syndromes in participants (N=85, 46 (54.1%) women, mean age 78 years (SD 6))ranged from 30.0% (malnutrition and cognitive impairment) to 71.0% (visual impairment), with a median number of 3 syndromes (IQR 2 to 4) per participant. Sensitivity of the BAT ranged from 25.0% for undernutrition (95%CI 9.8% - 46.7%) to 82.1% for hearing impairment (95%CI 66.5% - 92.5%), while specificity ranged from 45.8% for visual impairment (95%CI 25.6-67.2) to 87.7% for undernutrition (76.3% to 94.9%). Finally, most negative predictive values (NPV) were between 73.5% and 84.1%, excluding visual impairment with a NPV of 50.0%. Family physicians reported BAT use as per instructions for 76.7% of the syndromes assessed. Although the BAT does not replace a comprehensive geriatric assessment, it is a useful and appropriate tool for the FP to screen elderly patients for most geriatric syndromes. The study was registered on ClinicalTrials.gov on February 20, 2013 ( NCT01816087 )