3D imaging of magnetic domains in Nd2Fe14B using scanning hard X-ray nanotomography.

Nanoscale structural and electronic heterogeneities are prevalent in condensed matter physics. Investigating these heterogeneities in 3D has become an important task for understanding material properties. To provide a tool to unravel the connection between nanoscale heterogeneity and macroscopic emergent properties in magnetic materials, scanning transmission X-ray microscopy (STXM) is combined with X-ray magnetic circular dichroism. A vector tomography algorithm has been developed to reconstruct the full 3D magnetic vector field without any prior noise assumptions or knowledge about the sample. Two tomographic scans around the vertical axis are acquired on single-crystalline Nd2Fe14B pillars tilted at two different angles, with 2D STXM projections recorded using a focused 120 nm X-ray beam with left and right circular polarization. Image alignment and iterative registration have been implemented based on the 2D STXM projections for the two tilts. Dichroic projections obtained from difference images are used for the tomographic reconstruction to obtain the 3D magnetization distribution at the nanoscale.

A Deviance Regulation Theory Intervention Affects the Association Between Narcissistic Traits and Alcohol Harm Reduction Strategies in College Students.

Background: College students continue to report problematic alcohol use. To mitigate adverse outcomes, recent studies have employed harm reduction strategies known as Protective Behavioral Strategies (PBS). Deviance Regulation Theory (DRT), an impression management intervention, has been used to promote the use of PBS. DRT relies on impression management to modify behavior. This may be especially important for individuals with higher levels of trait narcissism. Method: College student drinkers (n = 132) were randomly assigned to receive a positive message about PBS users, a negative message about non-PBS users, or control. Participants reported on current PBS use norms, daily alcohol use, PBS use, and any alcohol-related problems experienced during the previous week for the next 10 weeks. Results: Data were analyzed using multilevel regression to examine PBS use across time by condition. When PBS norms were low, narcissism was strongly associated with lower rates of PBS use in the control group. If individuals received a positive or negative message, the association between narcissism and PBS use was diminished, among individuals with low PBS norms. There were no significant differences at mean or high levels of norms, indicating the messaging was only important for the highest risk group (i.e., those with low PBS norms). Discussion: The results of this study suggest that message framing may be effective at reducing the robust negative association between narcissism and PBS use for individuals with low PBS norms. Positive messages about individuals that use PBS may be one approach to mitigating problematic alcohol consumption in this at-risk group.

Mechanisms of Skyrmion and Skyrmion Crystal Formation from the Conical Phase.

Real-space topological magnetic structures such as skyrmions and merons are promising candidates for information storage and transport. However, the microscopic mechanisms that control their formation and evolution are still unclear. Here, using in situ Lorentz transmission electron microscopy, we demonstrate that skyrmion crystals (SkXs) can nucleate, grow, and evolve from the conical phase in the same ways that real nanocrystals form from vapors or solutions. More intriguingly, individual skyrmions can also "reproduce" by division in a mitosis-like process that allows them to annihilate SkX lattice imperfections, which is not available to crystals made of mass-conserving particles. Combined string method and micromagnetic calculations show that competition between repulsive and attractive interactions between skyrmions governs particle-like SkX growth, but nonconservative SkX growth appears to be defect mediated. Our results provide insights toward manipulating magnetic topological states by applying established crystal growth theory, adapted to account for the new process of skyrmion mitosis.

Dynamic Observation of Dendritic Quasicrystal Growth upon Laser-Induced Solid-State Transformation.

We report the laser-induced solid-state transformation between a periodic "approximant" and quasicrystal in the Al-Cr system during rapid quenching. Dynamic transmission electron microscopy allows us to capture in situ the dendritic growth of the metastable quasicrystals. The formation of dendrites during solid-state transformation is a rare phenomenon, which we attribute to the structural similarity between the two intermetallics. Through ab initio molecular dynamics simulations, we identify the dominant structural motif to be a 13-atom icosahedral cluster transcending the phases of matter.

Daily Patterns of Emotional Functioning on Drinking and Nondrinking Days.

BACKGROUND: Alcohol misuse continues to be a significant public health problem. Understanding the factors that may contribute to the harmful progression in drinking is an important aspect of public health. Previous research has shown that affect regulation is associated with problematic alcohol use. Additionally, emotion instability has been found as a predictor of alcohol-related problems and may be linked to reinforcement mechanisms. METHODS: The current study examined positive mood, negative mood, and mood instability in real time across drinking and nondrinking days utilizing ecological momentary assessment (EMA). Current drinkers (n = 74) were recruited for a 21-day EMA study. Participants completed up to 10 random assessments of positive mood, negative mood, and alcohol use per day. Mood instability was assessed as the squared difference in current mood from mood in the previous assessment. Data were analyzed using piecewise multilevel regression to examine mood trajectories across drinking and nondrinking days. RESULTS: Positive emotion across the day was higher on drinking days than nondrinking days and continued to increase after drinking initiation. In contrast, negative emotion across the day was lower on drinking days than nondrinking days and continued to decrease after drinking initiation. Emotional functioning was stable across the day on nondrinking days. However, on drinking days there was a steady increase in emotional instability leading up to drinking initiation, followed by a rapid stabilization after initiation. CONCLUSIONS: This study highlights the potentially reinforcing impact of alcohol via emotional stability. Overall, these findings highlight the importance of mood dynamics when examining the reinforcing effects of alcohol consumption.

Uncompensated Polarization in Incommensurate Modulations of Perovskite Antiferroelectrics.

Complex polar structures of incommensurate modulations (ICMs) are revealed in chemically modified PbZrO_{3} perovskite antiferroelectrics using advanced transmission electron microscopy techniques. The Pb-cation displacements, previously assumed to arrange in a fully compensated antiparallel fashion, are found to be either antiparallel, but with different magnitudes, or in a nearly orthogonal arrangement in adjacent stripes in the ICMs. Ab initio calculations corroborate the low-energy state of these arrangements. Our discovery corrects the atomic understanding of ICMs in PbZrO_{3}-based perovskite antiferroelectrics.

Cultivar Resistance to Common Scab Disease of Potato Is Dependent on the Pathogen Species.

Common scab of potato is a superficial tuber disease caused by Streptomyces species that produce the phytotoxin thaxtomin. Because common scab development is highly dependent on the effects of this single toxin, the current operating paradigm in common scab pathology is that a potato cultivar resistant to one strain of the common scab pathogen is resistant to all strains. However, cultivar resistance to common scab disease identified in one breeding program is often not durable when tested in other potato breeding programs across the United States. We infected 55 potato cultivar populations with three distinct species of the common scab pathogen and identified cultivars that were resistant or susceptible to all three species and cultivars that had widely varying resistance dependent on the pathogen species. Overall lower virulence was associated with the strain that produces the least thaxtomin. This result showcases several cultivars of potato that are expected to be resistant to the majority of common scab populations but also highlights that many potato cultivars are resistant to only specific species of the pathogen. These results demonstrate that extension specialists and growers must consider their local population of the common scab pathogen when selecting which cultivars to plant for common scab resistance.

Sternal wound complications in patients undergoing orthotopic heart transplantation.

PURPOSE: The incidence and management of sternal wound complications in patients undergoing orthotopic heart transplantation (OHT) is not well studied. We report outcomes in heart transplant patients who developed sternal infections requiring reoperations. METHODS: From 2004 to 2013, 437 patients underwent OHT at a single institution. In a retrospective review, patients who developed sternal infections (Infection group, n = 27) were compared with those without (Control group, n = 410). RESULTS: Sternal infection rate was 6.2% (n = 27). Demographics were similar (Table 1). Infection group had higher rates of COPD 25% vs 13%, P = 0.03, and previous cardiac surgery via median sternotomy 28% vs 15%, P = 0.03. Infection group had a greater incidence of prolonged ventilation, 44% vs 31%, P = 0.2, renal failure 56% vs 24%, P = 0.001, dialysis requirement 30% vs 10%, P = 0.006, permanent stroke 11% vs 2%, P = 0.02, perioperative myocardial infarction 4% vs 0.2%, P = 0.09. The infection group had a longer ICU stay (524 + 410 vs 187 + 355 hours, P = 0.001) and hospitalization (59 + 28 vs 0.29 + 43 days, P = 0.001). In-hospital/30-day mortality was 30% vs 19%, P = 0.2. The mean time for sternal reoperation at 44 + 50 days. Deep wound infection (41%) and sternal dehiscence (22%) were common presentations. Causative organisms were Enterobacter (22%), Klebsiella (15%), and Pseudomonas (15%). Vancomycin (44%), 4th generation cephalosporin (37%), and fluoroquinolones (30%) were the most commonly used antibiotics. Surgical treatment included sternal debridement with pectoralis muscle flap (52%), primary closure (18%), and omental flap (11%). CONCLUSION: Sternal wound infections impart a significant burden on patients with OHT. Causative organisms are predominantly virulent gram-negative bacteria. Therefore, a high index of suspicion must be maintained for early detection and treatment.

Protective Behavioral Strategies Moderate the Association between Narcissistic Traits and Alcohol Pathology in College Student Drinkers.

BACKGROUND: Personality traits found in Cluster B personality disorders have garnered considerable empirical attention and have been linked to a litany of issues, such as alcohol-related problems. While psychopathic traits have been linked to alcohol-use consequences, narcissistic traits remain understudied. OBJECTIVES: The current study examines the relationship between narcissistic traits and alcohol use and consequences as a function of Protective Behavioral Strategies (PBS) in a sample of college students. METHOD: Participants (n = 387 college student drinkers; 69.25% female) completed a series of questionnaires assessing alcohol use and consequences, PBS use, and narcissistic traits. RESULTS: There was a significant positive association between narcissistic traits and alcohol use and consequences. The interaction of PBS and narcissistic traits was also statistically significant. Simple slopes revealed that at high levels of PBS (+1SD), the relationship between narcissistic traits and alcohol-use consequences was attenuated and not significant, while at low levels of PBS (-1SD), this association was potentiated. CONCLUSION: These findings suggest that interventions targeting PBS use may be one way to reduce alcohol problems among those with higher levels of narcissistic traits.

Relaxation Dynamics of Zero-Field Skyrmions over a Wide Temperature Range.

The promise of magnetic skyrmions in future spintronic devices hinges on their topologically enhanced stability and the ability to be manipulated by external fields. The technological advantages of nonvolatile zero-field skyrmion lattice (SkL) are significant if their stability and reliability can be demonstrated over a broad temperature range. Here, we study the relaxation dynamics including the evolution and lifetime of zero-field skyrmions generated from field cooling (FC) in an FeGe single-crystal plate via in situ Lorentz transmission electron microscopy (L-TEM). Three types of dynamic switching between zero-field skyrmions and stripes are identified and distinguished. Moreover, the generation and annihilation of these metastable skyrmions can be tailored during and after FC by varying the magnetic fields and the temperature. This dynamic relaxation behavior under the external fields provides a new understanding of zero-field skyrmions for their stability and reliability in spintronic applications and also raises new questions for theoretical models of skyrmion systems.

From Quasicrystals to Crystals with Interpenetrating Icosahedra in Ca-Au-Al: In Situ Variable-Temperature Transformation.

The irreversible transformation from an icosahedral quasicrystal (i-QC) CaAu4.39Al1.61 to its cubic 2/1 crystalline approximant (CA) Ca13Au56.31(3)Al21.69 (CaAu4.33(1)Al1.67, Pa3̅ (No. 205); Pearson symbol: cP728; a = 23.8934(4)), starting at ∼570 °C and complete by ∼650 °C, is discovered from in situ, high-energy, variable-temperature powder X-ray diffraction (PXRD), thereby providing direct experimental evidence for the relationship between QCs and their associated CAs. The new cubic phase crystallizes in a Tsai-type approximant structure under the broader classification of polar intermetallic compounds, in which atoms of different electronegativities, viz., electronegative Au + Al vs electropositive Ca, are arranged in concentric shells. From a structural chemical perspective, the outermost shell of this cubic approximant may be described as interpenetrating and edge-sharing icosahedra, a perspective that is obtained by splitting the traditional structural description of this shell as a 92-atom rhombic triacontahedron into an 80-vertex cage of primarily Au [Au59.86(2)Al17.14□3.00] and an icosahedral shell of only Al [Al10.5□1.5]. Following the proposal that the cubic 2/1 CA approximates the structure of the i-QC and on the basis of the observed transformation, an atomic site analysis of the 2/1 CA, which shows a preference to maximize the number of heteroatomic Au-Al nearest neighbor contacts over homoatomic Al-Al contacts, implies a similar outcome for the i-QC structure. Analysis of the most intense reflections in the diffraction pattern of the cubic 2/1 CA that changed during the phase transformation shows correlations with icosahedral symmetry, and the stability of this cubic phase is assessed using valence electron counts. According to electronic structure calculations, a cubic 1/1 CA, "Ca24Au88Al64" (CaAu3.67Al2.67) is proposed.

Primary psychopathy and alcohol pathology in college students: The role of protective behavioral strategies.

OVERVIEW: Though not an official diagnosis, psychopathy has become an important area of research due to the litany of deleterious outcomes associated with this aspect of temperament. Psychopathy is composed of primary and secondary traits. Research consistently links psychopathy to alcohol pathology, though often only via secondary traits which are comprised of intractable aspects of behavior (e.g., poor impulse control). In contrast, primary psychopathy is comprised of behaviors that can be learned and thus may be more malleable (i.e., low harm reduction behaviors). OBJECTIVES: The current study examines associations between primary psychopathic traits and alcohol involvement as a function of Protective Behavioral Strategies (PBS) utilization in a sample of college students. METHOD: Participants (n = 936 college student drinkers; 66.56% female) completed a series of questionnaires assessing primary psychopathy, alcohol involvement, and PBS use. RESULTS: There was a significant positive association between primary psychopathy and alcohol consumption and pathology. This association was partially mediated via diminished PBS use. PBS use also moderated the relationship between alcohol consumption and pathology. The indirect effects from psychopathy to alcohol outcomes were attenuated at high (+1SD) PBS and potentiated at low (-1SD) PBS. CONCLUSION: The current findings suggest that some of the alcohol pathology associated with psychopathy is a function of lower harm reduction strategies among individuals with more psychopathic traits. These findings suggest that interventions targeting PBS use may be one way to reduce alcohol problems among those with higher levels of primary psychopathy.

Combinatorial study of Fe-Co-V hard magnetic thin films.

Thin film libraries of Fe-Co-V were fabricated by combinatorial sputtering to study magnetic and structural properties over wide ranges of composition and thickness by high-throughput methods: synchrotron X-ray diffraction, magnetometry, composition, and thickness were measured across the Fe-Co-V libraries. In-plane magnetic hysteresis loops were shown to have a coercive field of 23.9 kA m-1 (300 G) and magnetization of 1000 kA m-1. The out-of-plane direction revealed enhanced coercive fields of 207 kA m-1 (2.6 kG) which was attributed to the shape anisotropy of column grains observed with electron microscopy. Angular dependence of the switching field showed that the magnetization reversal mechanism is governed by 180° domain wall pinning. In the thickness-dependent combinatorial study, co-sputtered composition spreads had a thickness ranging from 50 to 500 nm and (Fe70Co30)100-xVx compositions of x = 2-80. Comparison of high-throughput magneto-optical Kerr effect and traditional vibrating sample magnetometer measurements show agreement of trends in coercive fields across large composition and thickness regions.

Israeli acute paralysis virus: epidemiology, pathogenesis and implications for honey bee health.

Israeli acute paralysis virus (IAPV) is a widespread RNA virus of honey bees that has been linked with colony losses. Here we describe the transmission, prevalence, and genetic traits of this virus, along with host transcriptional responses to infections. Further, we present RNAi-based strategies for limiting an important mechanism used by IAPV to subvert host defenses. Our study shows that IAPV is established as a persistent infection in honey bee populations, likely enabled by both horizontal and vertical transmission pathways. The phenotypic differences in pathology among different strains of IAPV found globally may be due to high levels of standing genetic variation. Microarray profiles of host responses to IAPV infection revealed that mitochondrial function is the most significantly affected biological process, suggesting that viral infection causes significant disturbance in energy-related host processes. The expression of genes involved in immune pathways in adult bees indicates that IAPV infection triggers active immune responses. The evidence that silencing an IAPV-encoded putative suppressor of RNAi reduces IAPV replication suggests a functional assignment for a particular genomic region of IAPV and closely related viruses from the Family Dicistroviridae, and indicates a novel therapeutic strategy for limiting multiple honey bee viruses simultaneously and reducing colony losses due to viral diseases. We believe that the knowledge and insights gained from this study will provide a new platform for continuing studies of the IAPV-host interactions and have positive implications for disease management that will lead to mitigation of escalating honey bee colony losses worldwide.

Short communication: On recognizing the proper experimental unit in animal studies in the dairy sciences.

Sound design of experiments combined with proper implementation of appropriate statistical methods for data analysis are critical for producing meaningful scientific results that are both replicable and reproducible. This communication addresses specific aspects of design and analysis of experiments relevant to the dairy sciences and, in so doing, responds to recent concerns raised in a letter to the editor of the Journal of Dairy Science regarding journal policy for research publications on pen-based animal studies. We further elaborate on points raised, rectify interpretation of important concepts, and show how aspects of statistical inference and elicitation of research conclusions are affected.

Correlative Energy-Dispersive X-Ray Spectroscopic Tomography and Atom Probe Tomography of the Phase Separation in an Alnico 8 Alloy.

Alnico alloys have long been used as strong permanent magnets because of their ferromagnetism and high coercivity. Understanding their structural details allows for better prediction of the resulting magnetic properties. However, quantitative three-dimensional characterization of the phase separation in these alloys is still challenged by the spatial quantification of nanoscale phases. Herein, we apply a dual tomography approach, where correlative scanning transmission electron microscopy (STEM) energy-dispersive X-ray spectroscopic (EDS) tomography and atom probe tomography (APT) are used to investigate the initial phase separation process of an alnico 8 alloy upon non-magnetic annealing. STEM-EDS tomography provides information on the morphology and volume fractions of Fe-Co-rich and Νi-Al-rich phases after spinodal decomposition in addition to quantitative information of the composition of a nanoscale volume. Subsequent analysis of a portion of the same specimen by APT offers quantitative chemical information of each phase at the sub-nanometer scale. Furthermore, APT reveals small, 2-4 nm Fe-rich α 1 phases that are nucleated in the Ni-rich α 2 matrix. From this information, we show that phase separation of the alnico 8 alloy consists of both spinodal decomposition and nucleation and growth processes. The complementary benefits and challenges associated with correlative STEM-EDS and APT are discussed.

Use of Mycelium and Detached Leaves in Bioassays for Assessing Resistance to Boxwood Blight.

Boxwood blight caused by Calonectria pseudonaviculata is a newly emergent disease of boxwood (Buxus spp. L.) in the United States that causes leaf drop, stem lesions, and plant death. A rapid and reliable laboratory assay that enables screening hundreds of boxwood genotypes for resistance to boxwood blight is needed to enable breeding and selection of resistant cultivars. Using eight boxwood cultivars with differing susceptibilities, we examined parameters for a screening assay comparing whole plant inoculation with detached leaf inoculation, use of mycelium versus spores as the inoculum, comparison of times of the year for inoculation, and comparison of two leaf inoculation methods. Inoculation of detached leaves gave comparable results to inoculation of whole plants when compared across genotypes, although the detached leaf assay resulted in greater percentages of symptom expression. The time of year of plant inoculation (spring, summer, or winter) did not affect the relative expression of symptoms among the most resistant and susceptible genotypes. Inoculating plants with mycelium was as effective as spore inoculation for causing disease symptoms and allowed us to distinguish the more resistant genotypes, yet mycelium inoculation was much easier to prepare in large quantities for multiple assays.

Chemical signals in terrestrial vertebrates: search for design features.

We compiled a data set of the compounds that terrestrial vertebrates (amniotes) use to send chemical signals, and searched for relationships between signal compound properties and signal function. Overall, relationships were scarce and formed only small-scale patterns. Terrestrial vertebrate signalling compounds are invariably components of complex mixtures of compounds with diverse molecular weights and functionalities. Signal compounds with high molecular weights (MWs) and low vapour pressures, or that are bound to carrier proteins, are detected during direct contact with the source of the signal. Stable compounds with aromatic rings in their structures are more common in signals of social dominance, including territoriality. Aldehydes are emitted from the sender's body rather than from scent marks. Lipocalin pheromones and carriers have a limited range of MWs, possibly to reduce the metabolic costs of their biosynthesis. Design constraints that might channel signal chemistry into patterns have been relaxed by amniote behavior and biochemistry. Amniote olfaction has such a high sensitivity, wide range and narrow resolution that signal detection imposes no practical constraints on the structures of signalling molecules. Diverse metabolic pathways in amniotes and their microbial commensals produce a wide variety of compounds as chemical signals and as matrix compounds that free signal components from the constraints of stability, vapor pressure, species-specificity etc. that would otherwise constrain what types of compound operate optimally under different conditions.

A high-throughput investigation of Fe-Cr-Al as a novel high-temperature coating for nuclear cladding materials.

High-temperature alloy coatings that can resist oxidation are urgently needed as nuclear cladding materials to mitigate the danger of hydrogen explosions during meltdown. Here we apply a combination of computationally guided materials synthesis, high-throughput structural characterization and data analysis tools to investigate the feasibility of coatings from the Fe­Cr­Al alloy system. Composition-spread samples were synthesized to cover the region of the phase diagram previous bulk studies have identified as forming protective oxides. The metallurgical and oxide phase evolution were studied via in situ synchrotron glancing incidence x-ray diffraction at temperatures up to 690 K. A composition region with an Al concentration greater than 3.08 at%, and between 20.0 at% and 32.9 at% Cr showed the least overall oxide growth. Subsequently, a series of samples were deposited on stubs and their oxidation behavior at 1373 K was observed. The continued presence of a passivating oxide was confirmed in this region over a period of 6 h.