Tips for research recruitment: The views of sexual minority youth

Researchers often experience difficulties recruiting hard-to-reach populations. This is especially so for studies involving those who have been historically stigmatized, such as individuals who challenge heteronormative expectations or people who experience mental ill health. The authors aimed to obtain the views of sexual minority adolescents (n=25) about what encouraged their participation in a research project. The authors used a general inductive approach to analyze interview data. Feedback consisted of 2 main overarching themes: tips and suggestions for future research and appreciate participants’ motivation to get involved in research. Strategies for how recruitment can be optimized for studies involving sexual minority young people are discussed

Current-driven and field-driven domain walls at nonzero temperature

We present a model for the dynamics of current- and field-driven domain-wall lines at nonzero temperature. We compute thermally-averaged drift velocities from the Fokker-Planck equation that describes the nonzero-temperature dynamics of the domain wall. As special limits of this general description, we describe rigid domain walls as well as vortex domain walls. In these limits, we determine also depinning times of the domain wall from an extrinsic pinning potential. We compare our theory with previous theoretical and experimental work

Spin motive forces due to magnetic vortices and domain walls

We study spin motive forces, i.e, spin-dependent forces, and voltages induced by time-dependent magnetization textures, for moving magnetic vortices and domain walls. First, we consider the voltage generated by a one-dimensional field-driven domain wall. Next, we perform detailed calculations on field-driven vortex domain walls. We find that the results for the voltage as a function of magnetic field differ between the one-dimensional and vortex domain wall. For the experimentally relevant case of a vortex domain wall, the dependence of voltage on field around Walker breakdown depends qualitatively on the ratio of the so-called $\beta$-parameter to the Gilbert damping constant, and thus provides a way to determine this ratio experimentally. We also consider vortices on a magnetic disk in the presence of an AC magnetic field. In this case, the phase difference between field and voltage on the edge is determined by the $\beta$ parameter, providing another experimental method to determine this quantity.Comment: 8 pages, 9 figures, submitted to PR

Fluctuations of current-driven domain walls in the non-adiabatic regime

We outline a general framework to determine the effect of non-equilibrium fluctuations on driven collective coordinates, and apply it to a current-driven domain wall in a nanocontact. In this case the collective coordinates are the domain-wall position and its chirality, that give rise to momentum transfer and spin transfer, respectively. We determine the current-induced fluctuations corresponding to these processes and show that at small frequencies they can be incorporated by two separate effective temperatures. As an application, the average time to depin the domain wall is calculated and found to be lowered by current-induced fluctuations. It is shown that current-induced fluctuations play an important role for narrow domain walls, especially at low temperatures.Comment: More computations, explanations, and results include

Optimizing propagating spin wave spectroscopy

The frequency difference between two oppositely propagating spin waves can be used to probe several interesting magnetic properties, such as the Dzyaloshinkii-Moriya interaction (DMI). Propagating spin wave spectroscopy is a technique that is very sensitive to this frequency difference. Here we show several elements that are important to optimize devices for such a measurement. We demonstrate that for wide magnetic strips there is a need for de-embedding. Additionally, for these wide strips there is a large parasitic antenna-antenna coupling that obfuscates any spin wave transmission signal, which is remedied by moving to smaller strips. The conventional antenna design excites spin waves with two different wave vectors. As the magnetic layers become thinner, the resulting resonances move closer together and become very difficult to disentangle. In the last part we therefore propose and verify a new antenna design that excites spin waves with only one wave vector. We suggest to use this antenna design to measure the DMI in thin magnetic layers.Comment: 12 pages, 4 figure

New Neurons in Aging Brains: Molecular Control by Small Non-Coding RNAs

Adult neurogenesis generates functional neurons from neural stem cells present in specific brain regions. It is largely confined to two main regions: the subventricular zone of the lateral ventricle, and the subgranular zone of the dentate gyrus (DG), in the hippocampus. With age, the function of the hippocampus and particularly the DG is impaired. For instance, adult neurogenesis is decreased with aging, in both proliferating and differentiation of newborn cells, while in parallel an age-associated decline in cognitive performance is often seen. Surprisingly, the synaptogenic potential of adult-born neurons is only marginally influenced by aging. Therefore, although proliferation, differentiation, and synaptogenesis of adult-born new neurons in the DG are closely related to each other, they are differentially affected by aging. In this review we discuss the crucial roles of a novel class of recently discovered modulators of gene expression, the small non-coding RNAs, in the regulation of adult neurogenesis. Multiple small non-coding RNAs are differentially expressed in the hippocampus. In particular a subgroup of the small non-coding RNAs, the microRNAs, fine-tune the progression of adult neurogenesis. This makes small non-coding RNAs appealing candidates to orchestrate the functional alterations in adult neurogenesis and cognition associated with aging. Finally, we summarize observations that link changes in circulating levels of steroid hormones with alterations in adult neurogenesis, cognitive decline, and vulnerability to psychopathology in advanced age, and discuss a potential interplay between steroid hormone receptors and microRNAs in cognitive decline in aging individuals

Evaluation of a Novel Rapid Test System for the Detection of Allergic Sensitization to Timothy Grass Pollen against Established Laboratory Methods and Skin Prick Test

Type I hypersensitivity is driven by allergen specific immunoglobulin E (sIgE) and thus sIgE represents a marker for modern allergy diagnosis. Recently, a rapid assay for the detection of sIgE, termed as (Allergy Lateral Flow Assay) ALFA, has been developed. The objective of our study is the evaluation of a scanner-based system for the semiquantitative interpretation of ALFA results. Agreement to Skin Prick Test (SPT, Allergopharma), ALLERG-O-LIQ System (Dr. Fooke), and ImmunoCAP (Phadia) was investigated using 50 sera tested for specific IgE to timothy grass pollen (g6). 35/50 sera were positive by SPT, ALLERG-O-LIQ, and ImmunoCAP. Excellent agreement was observed between ALFA results and SPT, ImmunoCAP, and ALLERG-O-LIQ. Area under the curve (AUC) values were found at 1.0, and 100% sensitivity and specificity was found versus all other methods. Visual- and scanner-based interpretation of the ALFA results revealed excellent agreement

Controlling magnetic skyrmion nucleation with Ga+ ion irradiation

In this paper, we show that magnetic skyrmion nucleation can be controlled using Ga+ ion irradiation, which manipulates the magnetic interface effects (in particular the magnetic anisotropy and Dzyaloshinskii-Moriya interaction) that govern the stability and energy cost of skyrmions in thin film systems. We systematically and quantitatively investigated what effect these changes have on the nucleation of magnetic skyrmions. Our results indicate that the energy cost of skyrmion nucleation can be reduced up to 26% in the studied dose range and that it scales approximately linearly with the square root of the domain-wall energy density. Moreover, the total number of nucleated skyrmions in irradiated devices after nucleation was found to depend linearly on the ion dose and could be doubled compared to nonirradiated devices. These results show that ion irradiation cannot only be used to enable local nucleation of skyrmions, but that it also allows for fine control of the threshold and efficiency of the nucleation process.Comment: Main: 17 pages, 3 figures; Supplemental Material: 7 pages, 5 figure