bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of a high DC magnetic field on spin reorientation in dysprosium- yttrium iron garnets at low temperatures
Authors: Zhu Tao , Wang Wei , Lahoubi Mahieddine , Boutaba Assia
Published: March 2019

In this work, magnetic properties of dysprosium doped yttrium iron garnet single crystals DyxY3-xFe5O12 (1 ≤ x ≤ 3) are studied in the 2-50 K temperature range under high D.C. magnetic fields H up to 16 T. When the sample is allowed to rotate freely on itself, critical points are observed and form a critical line of second order type which increases linearly with T in the magnetic phase diagram. This line is independent of the content x delimiting a canted phase which is issued from the low symmetry angular  phase occurring from the spontaneous spin reorientation below TSR (H = 0) = 14.62 K. In comparison with the free ion, the observed reduction at 0 K of the Dy3+ moments is also discussed.
Deformation of cellular components of bone forming cells when exposed to a magnetic field
Authors: Iwasaka M.
Published: March 2019

It has been suggested that alignment control of biological macromolecules and structures is possible when the diamagnetic energy is sufficient to overcome the thermal energy. Strong magnetic fields of several Tesla (T) have previously been shown to enable the observation of the magnetic orientations of protein fibers and suspended or adherent cells. In the present study, the fine structure of a bone-forming osteoblast cell line was observed in real-time under strong static magnetic fields of up to 5 T. The magnetic field was applied normal to the adhering surface, and induced slight deformation of cellular shape under bright field illumination. A newly developed dark field observation method presented more precise analysis of the inner structures of the cells in strong magnetic fields. Specifically, structures with a round appearance were clearly visualized around the cell nucleus using the electromagnetic illumination. In addition to the magnetically induced swelling of the round structures—which showed differences in diameter of several micrometers—color changes for these intracellular components were also detected using this technique. A high-resolution analysis of fine cellular structure based on the magnetic orientation of intracellular components including microtubules is proposed.
Investigation of large enhancement of spin hall angle in heterostructures of Ag nanoparticles randomly grown in Pt
Authors: Santos O. Alves , Silva E. F. , Gamino M. , Mendes J. B. S. , Rezende S. M. , Azevedo A.
Published: March 2019

The spin Hall angle (SHA) represents the efficiency of the conversion between spin current into charge current and vice-versa. In this paper, we report the experimental detection of large enhancement of the effective SHA in heterostructures of yttrium iron garnet (YIG)/[Pt-Ag]/Pt and YIG/[Pt-Ag], when compared with measurements in YIG/Pt bilayers. The notation [Pt-Ag] represents the nanoparticles island formation of Ag in the Pt film. In order to investigate the role played by the metallic nanoparticles in the spin-to-charge conversion process, we carried out microwave spin pumping measurements in the following samples: YIG/Ag(3 nm)/Pt(6 nm), YIG/[Pt(3 nm)-Ag(3 nm)]/Pt(3 nm) and YIG/[Pt(6 nm)-Ag(3 nm)]. By means of high-resolution scanning electron microscope (HR-SEM) investigation, we confirmed that layers of Ag exhibit islands nanoparticle structures when grown on the surface of the Pt, which are characterized by the Volmer-Weber mode. The spin pumping results show that the Ag nanoparticles can enhance the charge current created by the inverse spin Hall effect (IISHE) up to three times larger than the single Pt layer. Also, by analyzing atomic force microscopy (AFM) images, obtained for samples with different thickness of the Ag layer, we conclude that the roughness plays an important role in the enhancement of the IISHE. Therefore, taking advantage of poor wetting properties of Ag over Pt layer, it was possible to create nanoscopic particles of Ag randomly grown in the Pt layer. The nanoparticles serve as nanoscopic molds to locally increase the SHA. This feature represents an improvement in searching more efficient methods of the spin-to-charge conversion and opens up the possibility of tuning the SHA by controlling the size and shape of the Ag nanoparticles.
Peculiar magnetotransport properties in La0.67Sr0.33MnO3/LaAlO3/SrTiO3
Authors: Yamanouchi Michihiko , Oyamada Tatsuro , Ohta Hiromichi
Published: March 2019

We have investigated the planar Hall effect (PHE) and the anisotropic magnetoresistance (AMR) in La0.67Sr0.33MnO3/LaAlO3/SrTiO3 (LSMO/LAO/STO) and LSMO/STO structures, where the LSMO (LAO) thickness was 13 unit cells (u.c.) and 18 u.c. (8 u.c. and 6 u.c.). The LAO/STO structures under the LSMO layers are conductive, which is consistent with the formation of a two-dimensional electron system (2DES) at the LAO/STO interface. The magnetotransport measurements show that the sign of the PHE coefficient for the LSMO/LAO/STO structures is opposite to that for the LSMO/STO structures, whereas the AMR coefficient, which is generally correlated with the PHE coefficient, is negative for both structures at temperatures below ∼175 K. The LAO/STO structures show no apparent PHE or AMR, and the coefficients obtained thus originate from the LSMO. These results suggest that the 2DES and/or the LSMO/LAO interface affect the PHE in the LSMO layer.
Fabrication, structural and magnetic properties of one-dimensional anti-ferromagnetic FeMn nanostructures
Authors: Ali S. S. , Li W. J. , Zhang X. M. , Irfan M. , Feng J. F. , Javed K. , Zhai G. J. , Han X. F.
Published: March 2019

FeMn nanowires have been synthesized by employing DC electro-deposition technique provided with constant stirring during the growth. The use of anodic aluminum oxide (AAO) templates made it possible to get well aligned nanowires with average diameter around 100 nm. Magnetic field annealing with field strength of 1 T applied at angle 0° and 90° to nanowires axis at different annealing temperatures has been employed to study the variation in structural and magnetic properties of nanowires. XRD analysis shows poor crystallinity of as-synthesized arrays but cubic structure with (110) preferred orientation has been resulted after the annealing process. Furthermore, vibrating sample magnetometer (VSM) has been employed to study the saturation magnetization (Ms), squareness ratio (SQ=Mr/Ms) and coercivity (Hc) of the as-synthesized and annealed samples. The as deposited and annealed NWs arrays show the coherent rotation for magnetization reversal process.
A nanocalorimetric study of the effect of composition gradients on crystallization in amorphous Cu-Zr thin films
Authors: Arlington Shane Q. , Yi Feng , LaVan David A. , Weihs Timothy P.
Published: March 2019

Nucleation, the initial formation of a new phase from a parent phase, plays an important role in the eventual microstructure and properties of materials. Theories and models of nucleation have been integral to materials science for close to a century. These models assume that the parent material is compositionally homogeneous on length-scales relevant to nucleation. However, in certain materials – such as thin films or reactive nanolaminates – sharp gradients in the composition may influence nucleation. Models and theories exploring these impacts are based on little direct experimental data. Here we present means of producing and characterizing samples with composition gradients to measure the impacts of gradients on nucleation. We fabricate amorphous Cu-Zr films with known composition gradients through their thicknesses; we perform isochronal nanocalorimetry to measure the impact of the gradients on nucleation and growth; and we characterize the samples before and after reaction. We see evidence of phase separation of the vapor-quenched Cu-Zr amorphous films. While we measure differences between the samples with gradients and those without, the gradients relax sufficiently during heating such that nucleation (the onset of crystallization) occurs at the same temperatures. For both sets of samples we find three distinct regions of heat release: the first we attribute to local ordering, the second to extended phase separation and interdiffusion, and the third to nucleation and growth of the Cu10Zr7 crystalline phase. This work represents a first step towards investigating the impact of gradients on nucleation, as well as growth.
Structural characterization of the LaInO3/BaSnO3 interface via synchrotron scattering
Authors: Lau Claudia , Kim Youjung , Albright Stephen , Char Kookrin , Ahn C. H. , Walker F. J.
Published: March 2019

The alkaline earth stannate BaSnO3 is a semiconductor with high carrier mobility at room-temperature when doped with La3+. When a thin epitaxial layer of LaInO3 is grown on lightly doped BaSnO3, a polar discontinuity between the orthorhombic, polar LaInO3 and the cubic, nonpolar Ba0.998La0.002SnO3 leads to an electronic reconstruction, where LaInO3 remotely dopes Ba0.998La0.002SnO3, creating carriers for high mobility devices. We determine aspects of the crystalline structure of the LaInO3/BaSnO3 film that affect the polar discontinuity using synchrotron x-ray diffraction. Specifically, we examine the role of oxygen octahedral rotations and anti-parallel cation displacements in influencing the polarization of the LaInO3/BaSnO3 interface. These structural distortions are characterized by measuring half-order Bragg peaks of thin film LaInO3/BaSnO3/SrTiO3 heterostructures grown by pulsed laser deposition. We find that for films as thin as 3 unit cells, epitaxial LaInO3 has 2 distinct domains, one with the same Glazer tilt pattern as that of bulk LaInO3, a+b−b−, and a second rotated 90° in-plane from the first and having tilt pattern b−a+b−. Additionally, we observe a sudden and large increase in cation displacements along the [011] and [101] directions across the LaInO3/BaSnO3 interface due to the strength of the octahedral rotations.
A combination of electrical spark and laser-induced breakdown spectroscopy on a heated sample
Authors: Hassanimatin M. M. , Tavassoli S. H. , Nosrati Y. , Safi A.
Published: March 2019

Signal enhancement in laser-induced breakdown spectroscopy (LIBS) is the concern of many research groups. In order to increase the spectral emission of LIBS, a combination of electrical spark and laser-induced breakdown spectroscopy (SA-LIBS) on a heated sample (SA-LIBS-HS) is studied. The mechanism of increasing the signal is examined, and a comparison between the calculated signal enhancement and the experimental one is done. It is shown that the plasma temperature and the amount of ablation mass are the main factors for signal enhancement. As a secondary source of excitation, the electrical spark leads to an increase in the plasma temperature. Heating the sample causes an increase in the ablation mass and the plasma temperature. By heating the sample and consequently lowering the ablation threshold as well as using an electrical spark, a significant signal intensity is observed at low laser pulse energies. This study demonstrates the capability of the SA-LIBS-HS method for the further improvement of LIBS and SA-LIBS applications.
Chemical bonding and nonadiabatic electron wavepacket dynamics in densely quasi-degenerate excited electronic state manifold of boron clusters
Authors: Arasaki Yasuki , Takatsuka Kazuo
Published: March 2019

Formation of chemical bonds is theoretically discerned by the presence of static nuclear configuration on a potential energy surface given within the Born–Oppenheimer framework. We here study dynamical chemical bonding for molecules residing in the electronic excited states that are in a densely quasi-degenerate electronic state manifold and thereby keep undergoing extremely frequent nonadiabatic transitions. For this type of the states, the notion of global potential energy surfaces based on the adiabatic representation loses the usual sense. Nonetheless, chemical bonding exists and associated chemical reactions certainly proceed, for which we call chemistry without potential surfaces. As such, we investigate the highly excited states of boron clusters, which have extraordinarily long lifetimes with neither ionization nor dissociation. The dynamical chemical bonds keep rearranging themselves without converging to a static structure, the vivid electron dynamics of which is tracked by means of the nonadiabatic electron wavepacket dynamics theory. To characterize the dynamical bonding theoretically, we propose the notion of hyper-resonance.
Study of stretched H2 reveals new class of error in density functional theory
Authors: Liebendorfer Adam
Published: March 2019

Poor spin density localization in elongated single bonds can lead to qualitative failure in predicting properties such as static polarizability and force constants.
Increasing population size can inhibit cumulative cultural evolution
Authors: Fay Nicolas , De Kleine Naomi , Walker Bradley , Caldwell Christine A.
Published: March 2019

The extent to which larger populations enhance cumulative cultural evolution (CCE) is contentious. We report a large-scale experiment (n= 543) that investigates the CCE of technology (paper planes and their flight distances) using a transmission-chain design. Population size was manipulated such that participants could learn from the paper planes constructed by one, two, or four models from the prior generation. These social-learning conditions were compared with an asocial individual-learning condition in which individual participants made repeated attempts at constructing a paper plane, without having access to any planes produced by other participants. Larger populations generated greater variation in plane performance and gave participants access to better-adapted planes, but this did not enhance CCE. In fact, there was an inverse relationship between population size and CCE: plane flight distance did not improve over the experimental generations in the 2-Model and 4-Model conditions, but did improve over generations in the 1-Model social-learning condition. The incremental improvement in plane flight distance in the 1-Model social-learning condition was comparable to that in the Individual Learning condition, highlighting the importance of trial-and-error learning to artifact innovation and adaptation. An exploratory analysis indicated that the greater variation participants had access to in the larger populations may have overwhelmed their working memory and weakened their ability to selectively copy the best-adapted plane(s). We conclude that larger populations do not enhance artifact performance via CCE, and that it may be only under certain specific conditions that larger population sizes enhance CCE.
Bipotent stem cells support the cyclical regeneration of endometrial epithelium of the murine uterus
Authors: Jin Shiying
Published: March 2019

Significance

Disorders of endometrial epithelial regeneration result in severe pathological conditions, including uterine cancer, endometriosis, and infertility. The lack of a detailed understanding of the cellular mechanisms underlying endometrial epithelial regeneration during the mouse estrous cycle or human menstrual cycle hinders the effective treatment of such diseases. Here, I demonstrate that the mouse uterine endometrial epithelium is maintained by a resident tissue stem cell population. These stem cells survive cyclical uterine tissue loss and persistently generate all endometrial epithelial lineages during a female’s reproductive lifespan. Such findings in mice should facilitate the study of human uterine stem cells and regeneration, which will further the understanding of uterine physiology and pathology.
Interfacial engineering of cobalt sulfide/graphene hybrids for highly efficient ammonia electrosynthesis
Authors: Chen Pengzuo , Zhang Nan , Wang Sibo , Zhou Tianpei , Tong Yun , Ao Chengcheng , Yan Wensheng , Zhang Lidong , Chu Wangsheng , Wu Changzheng , Xie Yi
Published: March 2019

Significance

Ammonia is one of the most important chemical raw materials with an annual production exceeding 200 million tons. The Haber–Bosch process is still the dominant route for industrial ammonia synthesis, which consumes 1∼3% of global annual energy production and represents a significant contributor to climate change. Electrocatalytic N
2
reduction reaction is an attractive alternative candidate for carbon-free and sustainable NH
3
production, but often suffers from low efficiency. Here, we developed an interfacial engineering strategy for preparing a class of strongly coupled hybrid electrocatalysts for N
2
fixation. The hybrids exhibit superior N
2
reduction reaction activity with a high NH
3
Faradaic efficiency of 25.9% under ambient conditions. This strategy provides an approach to design advanced materials for ammonia production.
Gold-implanted plasmonic quartz plate as a launch pad for laser-driven photoacoustic microfluidic pumps
Authors: Yue Shuai , Lin Feng , Zhang Qiuhui , Epie Njumbe , Dong Suchuan , Shan Xiaonan , Liu Dong , Chu Wei-Kan , Wang Zhiming , Bao Jiming
Published: March 2019

Significance

A revolutionary microfluidic pump is demonstrated; it has no moving parts and no electrical contacts. It consists of a quartz plate implanted by Au particles where every point on the plate can function as a micropump. The pump is driven by a laser beam and is based on the discovered principle of photoacoustic laser streaming. When a pulsed laser hits the plate, it is absorbed by Au nanoparticles that generate an ultrasound wave, which then drives the fluid via acoustic streaming. Because laser beams can be arbitrarily patterned and timed, the fluid can be controlled by laser in a fashion similar to musical water fountains. Such a laser-driven photoacoustic micropump will find wide applications in microfluidics and optofluidics.
Tracking the rotation of single CdS nanorods during photocatalysis with surface plasmon resonance microscopy
Authors: Jiang Yingyan , Su Hua , Wei Wei , Wang Yongjie , Chen Hong-Yuan , Wang Wei
Published: March 2019

Significance

Rotational dynamics of anisotropic nanomaterials reveals and regulates their behaviors and functions in diverse fields ranging from nanomotors, biomechanics, and enzymatic catalysis to microrheology. An optical imaging technique that is suitable for all kinds of anisotropic nanoobjects, regardless of its inherent optical property, is thus highly desirable and it is yet to be demonstrated. In the present work, by taking a nonfluorescent and nonplasmonic CdS nanorod as an example, we demonstrate the capability of a recently developed surface plasmon resonance microscopy for determining the orientation of single anisotropic nanomaterials with arbitrary chemical composition and morphology.
Evidence-based management of injurious pecking.
Authors: Niekerk T. van
Published: March 2019

Injurious pecking in laying hen flocks comprises feather pecking and tissue pecking, the latter often referred to as cannibalism. Although some gentle feather pecking belongs to the natural repertoire of laying hens, the more vigorous form, severe feather pecking, is considered an abnormal behaviour. Various theories have been developed to explain the onset of injurious pecking. All point to suboptimal circumstances leading to abnormal or redirected behaviour. A wide range of husbandry and management factors have been identified. They affect either the onset of injurious pecking (prevention) or its reduction. Prevention is most important, because once started the behaviour is very hard to stop. Therefore the first focus should be on optimizing rearing conditions to prevent injurious pecking. The most important management strategy in rear is a continuous presence of high-quality substrate to stimulate foraging behaviour and to allow the pullets to develop a habit of directing their pecking towards the litter. Any stressor can be a trigger for injurious pecking. This means management should also focus on the prevention of stressful events. Such stressful events may be changes in housing conditions (e.g. transition from rear to lay, climate) and management (e.g. light, feed, access to range), but also suboptimal health, especially parasites and compromised intestinal health. Finally some husbandry conditions seem to increase the propensity to develop injurious pecking, such as large flock sizes and a higher bird density. Management to prevent injurious pecking can only be successful if it aims at optimizing all factors involved.
Sox8 is essential for M cell maturation to accelerate IgA response at the early stage after weaning in mice
Authors: Kimura Shunsuke , Kobayashi Nobuhide , Nakamura Yutaka , Kanaya Takashi , Takahashi Daisuke , Fujiki Ryoji , Mutoh Mami , Obata Yuuki , Iwanaga Toshihiko , Nakagawa Tomoo , Kato Naoya , Sato Shintaro , Kaisho Tsuneyasu , Ohno Hiroshi , Hase Koji
Published: March 2019

Microfold (M) cells residing in the follicle-associated epithelium (FAE) of the gut-associated lymphoid tissue are specialized for antigen uptake to initiate mucosal immune responses. The molecular machinery and biological significance of M cell differentiation, however, remain to be fully elucidated. Here, we demonstrate that Sox8, a member of the SRY-related HMG box transcription factor family, is specifically expressed by M cells in the intestinal epithelium. The expression of Sox8 requires activation of RANKL-RelB signaling. Chromatin immunoprecipitation and luciferase assays revealed that Sox8 directly binds the promoter region of Gp2 to increase Gp2 expression, which is the hallmark of functionally mature M cells. Furthermore, genetic deletion of Sox8 causes a marked decrease in the number of mature M cells, resulting in reduced antigen uptake in Peyer’s patches. Consequently, juvenile Sox8-deficient mice showed attenuated germinal center reactions and antigen-specific IgA responses. These findings indicate that Sox8 plays an essential role in the development of M cells to establish mucosal immune responses.
High-Grade Squamous Intraepithelial Lesion of the Gastroesophageal Junction Secondary to High-Risk Human Papillomavirus
Authors: Stelow Edward B , Dill Erik A , Davick Jonathan J , McCabe Michael B , Shami Vanessa M
Published: March 2019

Objectives

Although the role of human papillomavirus (HPV) in the development of some carcinomas (eg, anogenital and oropharyngeal squamous cell carcinomas) is nondebatable, there is still significant controversy regarding the relationship of HPV and esophageal squamous cell carcinomas (SCCs).

Methods

All cases were sampled at or near the gastroesophageal junctions in patients with reflux and/or known Barrett esophagus and appear to have been initially sampled “incidentally.” Patients were all men, aged 56 to 80 years. None had a known history of other HPV-related disease.

Results

We present four cases of high-grade squamous intraepithelial lesion of the gastroesophageal junction secondary to high-risk HPV that have identical histologic features to similar lesions of the anogenital tract.

Conclusions

Whether such lesions are at risk for developing into invasive SCC remains unclear.
Are We Measuring What Really Counts?
Authors: Thoma Achilleas , Hassan Yusuf , Santos Jenny
Published: March 2019

Most published clinical research is faulty because of many reasons, one being faulty design. A remedy to this problem is the correct utilization of the PICOT (population, intervention, comparative intervention, outcome and time horizon) format in the design of a clinical research question. One element of the PICOT format, “outcome,” has not been assessed adequately in aesthetic surgery. In this review, we found that in the last decade of all randomized controlled trials and comparative studies published in Aesthetic Surgery Journal, only about half specified a primary outcome. Regrettably, only 40% reported both a primary outcome and justification for choosing this outcome. This poses a credibility issue with the conclusions of the majority of published studies. There is an urgent need to develop critical outcome sets for aesthetic procedures to be utilized by future investigators. With such a critical outcome set, we will be able to pool the results of multiple studies on the same subject and reach conclusive results.
iLearn: an integrated platform and meta-learner for feature engineering, machine-learning analysis and modeling of DNA, RNA and protein sequence data
Authors: Chen Zhen , Zhao Pei , Li Fuyi , Marquez-Lago Tatiana T , Leier André , Revote Jerico , Zhu Yan , Powell David R , Akutsu Tatsuya , Webb Geoffrey I , Chou Kuo-Chen , Smith A Ian , Daly Roger J , Li Jian , Song Jiangning
Published: March 2019

With the explosive growth of biological sequences generated in the post-genomic era, one of the most challenging problems in bioinformatics and computational biology is to computationally characterize sequences, structures and functions in an efficient, accurate and high-throughput manner. A number of online web servers and stand-alone tools have been developed to address this to date; however, all these tools have their limitations and drawbacks in terms of their effectiveness, user-friendliness and capacity. Here, we present iLearn, a comprehensive and versatile Python-based toolkit, integrating the functionality of feature extraction, clustering, normalization, selection, dimensionality reduction, predictor construction, best descriptor/model selection, ensemble learning and results visualization for DNA, RNA and protein sequences. iLearn was designed for users that only want to upload their data set and select the functions they need calculated from it, while all necessary procedures and optimal settings are completed automatically by the software. iLearn includes a variety of descriptors for DNA, RNA and proteins, and four feature output formats are supported so as to facilitate direct output usage or communication with other computational tools. In total, iLearn encompasses 16 different types of feature clustering, selection, normalization and dimensionality reduction algorithms, and five commonly used machine-learning algorithms, thereby greatly facilitating feature analysis and predictor construction. iLearn is made freely available via an online web server and a stand-alone toolkit.
Freshwater-to-marine transitions may explain the evolution of herbivory in the subgenus Mollienesia (genus Poecilia, mollies and guppies)
Authors: Sanchez Jessica L , Bracken-Grissom Heather D , Trexler Joel C
Published: March 2019

The ability of organisms to cross ecosystem boundaries is an important catalyst of evolutionary diversification. The genus Poecilia (mollies and guppies) is an excellent system for studying ecosystem transitions because species display a range of salinity and dietary preferences, with herbivory concentrated in the subgenus Mollienesia. We reconstructed ancestral habitats and diets across a phylogeny of the genus Poecilia, evaluated diversification rates and used phylogenetically independent contrasts to determine whether diet evolved in response to habitat transition in this group. The results suggest that ancestors of subgenus Mollienesia were exclusively herbivorous, whereas ancestral diets of other Poecilia included animals. We found that transitions across euryhaline boundaries occurred at least once in this group, probably after the divergence of the subgenus Mollienesia. Furthermore, increased salinity affiliation explained 24% of the decrease in animals in the gut, and jaw morphology was associated with the percentage of animals in the gut, but not with the percentage of species occupying saline habitats. These findings suggest that in the genus Poecilia, herbivory evolved in association with transitions from fresh to euryhaline habitats, and jaw morphology evolved in response to the appearance of herbivory. These results provide a rare example of increased diet diversification associated with the transition from freshwater to euryhaline habitats.
Psychophysics of the hoverfly: categorical or continuous color discrimination?
Authors: Hannah Lea , Dyer Adrian G , Garcia Jair E , Dorin Alan , Burd Martin
Published: March 2019

There is increasing interest in flies as potentially important pollinators. Flies are known to have a complex visual system, including 4 spectral classes of photoreceptors that contribute to the perception of color. Our current understanding of how color signals are perceived by flies is based on data for the blowfly Lucilia sp., which after being conditioned to rewarded monochromatic light stimuli, showed evidence of a categorical color visual system. The resulting opponent fly color space has 4 distinct categories, and has been used to interpret how some fly pollinators may perceive flower colors. However, formal proof that flower flies (Syrphidae) only use a simple, categorical color process remains outstanding. In free-flying experiments, we tested the hoverfly Eristalis tenax, a Batesian mimic of the honeybee, that receives its nutrition by visiting flowers. Using a range of broadband similar–dissimilar color stimuli previously used to test color perception in pollinating hymenopteran species, we evaluated if there are steep changes in behavioral choices with continuously increasing color differences as might be expected by categorical color processing. Our data revealed that color choices by the hoverfly are mediated by a continuous monotonic function. Thus, these flies did not use a categorical processing, but showed evidence of a color discrimination function similar to that observed in several bee species. We therefore empirically provide data for the minimum color distance that can be discriminated by hoverflies in fly color space, enabling an improved understanding of plant–pollinator interactions with a non-model insect species.
Overcoming long Bayesian run times in integrated fisheries stock assessments
Authors: Monnahan Cole C , Branch Trevor A , Thorson James T , Stewart Ian J , Szuwalski Cody S
Published: March 2019

Bayesian inference is an appealing alternative to maximum likelihood estimation, but estimation can be prohibitively long for integrated fisheries stock assessments. Here, we investigated potential causes of long run times including high dimensionality, complex model structure, and inefficient Bayesian algorithms for four US assessments written in AD Model Builder (ADMB), both custom built and Stock Synthesis models. The biggest culprit for long run times was overparameterization and they were reduced from months to days by adding priors and turning off estimation for poorly-informed parameters (i.e. regularization), especially for selectivity parameters. Thus, regularization is a necessary step in converting assessments from frequentist to Bayesian frameworks. We also tested the usefulness of the no-U-turn sampler (NUTS), a Bayesian algorithm recently added to ADMB, and the R package adnuts that allows for easy implementation of NUTS and parallel computation. These additions further reduced run times and better sampled posterior distributions than existing Bayesian algorithms in ADMB, and for both of these reasons we recommend using NUTS for inference. Between regularization, a faster algorithm, and parallel computation, we expect models to run 50–50 000 times faster for most current stock assessment models, opening the door to routine usage of Bayesian methods for management of fish stocks.
Postoperative atrial fibrillation after aortic valve replacement is a risk factor for long-term atrial fibrillation
Authors: Carter-Storch Rasmus , Dahl Jordi S , Christensen Nicolaj L , Pecini Redi , Søndergård Eva V , Øvrehus Kristian Altern , Møller Jacob E
Published: March 2019

OBJECTIVES

Postoperative atrial fibrillation (POAF) is a common complication following cardiac surgery. However, knowledge on the rate of long-term atrial fibrillation (LTAF) after POAF remains unclear. We investigated predictors of POAF in patients with aortic stenosis undergoing surgical aortic valve replacement, and assessed the rate of LTAF during follow-up.

METHODS

We prospectively included 96 adult patients with severe aortic stenosis undergoing surgical aortic valve replacement. Patients with previous atrial fibrillation (AF) were excluded. Patients underwent echocardiography, cardiac computed tomography and magnetic resonance imaging immediately prior to surgery. Surgical aortic clamp time and postoperative C-reactive protein (CRP) were documented. POAF was defined as AF recorded within 7 days of surgery. Through chart review, patients were followed up for documented episodes of LTAF occurring more than 7 days after surgery.

RESULTS

POAF occurred in 51 patients (53%). It was associated with larger preoperative echocardiographic left atrial volume index (44 ± 12 vs 37 ± 8 ml/m2, P = 0.004), longer aortic clamp time [80 (70–102) vs 72 (62–65) min, P = 0.04] and higher CRP on first postoperative day [80 (64–87) vs 65 (44–83) mg/l, P = 0.001]. Multivariable logistic regression revealed that left atrial volume index [odds ratio (OR) 1.07, 95% confidence interval (CI) 1.02–1.13; P = 0.005] and postoperative CRP (OR 1.03, 95% CI 1.01–1.05; P = 0.006) were the only independent predictors of POAF. During 695 days (25th–75th percentile: 498–859 days) of follow-up, LTAF occurred in 11 patients of whom 10 were in the POAF group (hazard ratio 9.4, 95% CI 1.2–74; P = 0.03).

CONCLUSIONS

POAF is predicted by left atrial volume index and postoperative CRP. Patients with POAF have a 9-fold increase risk of developing symptomatic LTAF during follow-up.

Clinical trial registration number

ClinicalTrials.gov (NCT02316587).
La ‘terza stanza de quadri’ in Palazzo Farnese nel 1644
Authors: Pierguidi Stefano
Published: March 2019

L’articolo punta a stabilire il criterio museografico nell’allestimento della ‘terza stanza de quadri’ in Palazzo Farnese nel 1644, a partire dalla sorprendente presenza in quell’ambiente di molti disegni incorniciati accanto a dipinti su tavola a fondo oro di primo Quattrocento e a poche, importanti tele. Nella stanza era sinteticamente narrata la storia della pittura a Roma dal Quattro al Cinquecento, attraverso soli capolavori, di maestri quasi unicamente appartenenti alla scuola romana.

This article aims to establish the museographic criteria involved in the display of pictures in the ‘third room of paintings’ in the Palazzo Farnese in 1644, beginning with the surprising presence there of many framed drawings next to paintings on panel with gold background of the early fifteenth century and with few modern paintings of great importance. Here the story of painting in Rome in the Quattrocento and Cinquecento was synthetically narrated through masterpieces belonging almost exclusively to the Roman School.
Respect for Home and the Family
Authors: Fiala-Butora János
Published: March 2019

This chapter examines Article 23 of the United Nations Convention on the Rights of Persons with Disabilities. The right to family life and its various components have long been recognized by international human rights law and in regional human rights instruments. Despite this long tradition of protecting the family in human rights law, persons with disabilities have long been subject to serious violations of their right to family life. The prevailing stereotype has considered persons with disabilities asexual, which has led to the denial of their sexual autonomy. The right to family life also encompasses all forms of relationships and parenthood. To be truly equal members of society, persons with disabilities must achieve equality of opportunity in these areas as well. This requires significant attitudinal change, empowerment, dismantling of barriers, and support to experience intimate relationships.
Education
Authors: Anastasiou Dimitris , Gregory Michael , Kauffman James M
Published: March 2019

This chapter examines Article 24 of the United Nations Convention on the Rights of Persons with Disabilities (CRPD), which recognizes the right of persons with disabilities (PWD) to education and lifelong learning, specifying obligations of states parties that are necessary for realizing this right. Consistent with the CRPD as a whole and with other human rights treaties, it seeks to eliminate discrimination against and equalize educational opportunities for PWD. Nevertheless, it is argued that several tensions and ambiguities embodied in Article 24 raise questions about its efficacy for ultimately achieving its important vision. Despite its categorization as an ‘economic, social, and cultural right’, Article 24 appears to operate in practice primarily as an anti-discrimination measure, which inhibits its potential for securing socio-economic justice for all PWD. In this regard, it diverges from the paradigm that has characterized other international statements on the right to education.
Conference of States Parties
Authors: Bantekas Ilias
Published: March 2019

This chapter examines Article 40 of the United Nations Convention on the Rights of Persons with Disabilities (CRPD), which deals with the Conference of States Parties (COSP). The COSP is part of an established tradition whose principal aim is to keep the Convention alive by stimulating actions, collaborations, enforcement, capacity building, and others. The enforcement powers of the COSP are severely limited, if any, and should not therefore be compared to those enjoyed by entities with enforcement powers, such as the UN Security Council or the Council of the European Union. Although the powers and functions of the COSP could be achieved outside the legal person of the COSP on the basis of joint action by CRPD member states, the formal collectivization of member states ensures annual discussions on important and emerging issues affecting disability rights and contributes towards a consistency among a group of equal partners undertaking the same obligations.
Atmospheric mass-loss due to giant impacts: the importance of the thermal component for hydrogen–helium envelopes
Authors: Biersteker John B , Schlichting Hilke E
Published: March 2019

Systems of super-Earths and mini-Neptunes display striking variety in planetary bulk density and composition. Giant impacts are expected to play a role in the formation of many of these worlds. Previous works, focused on the mechanical shock caused by a giant impact, showed that these impacts can eject large fractions of the planetary envelope, offering a partial explanation for the observed compositional diversity. Here, we examine the thermal consequences of giant impacts, and show that the atmospheric loss caused by these effects can significantly exceed that caused by mechanical shocks for hydrogen–helium (H/He) envelopes. During a giant impact, part of the impact energy is converted into thermal energy, heating the rocky core and envelope. We find that the ensuing thermal expansion of the envelope can lead to a period of sustained, rapid mass-loss through a Parker wind, partly or completely eroding the H/He envelope. The degree of atmospheric loss depends on the planet’s orbital distance from its host star and its initial thermal state, and hence age. Close-in planets and younger planets are more susceptible to impact-triggered atmospheric loss. For planets where the heat capacity of the core is much greater than the envelope’s heat capacity (envelope mass fractions ≲4 per cent), the impactor mass required for significant atmospheric removal is Mimp/Mp ∼ μ/μc ∼ 0.1, approximately the ratio of the heat capacities of the envelope and core. Conversely, when the envelope dominates the planet’s heat capacity, complete loss occurs when the impactor mass is comparable to the envelope mass.
System initial mass function of the 25 Ori group from planetary-mass objects to intermediate/high-mass stars
Authors: Suárez Genaro , Downes Juan José , Román-Zúñiga Carlos , Cerviño Miguel , Briceño César , Petr-Gotzens Monika G , Vivas Katherina
Published: March 2019

The stellar initial mass function (IMF) is an essential input for many astrophysical studies but only in a few cases has it been determined over the whole cluster mass range, limiting the conclusions about its nature. The 25 Orionis group (25 Ori) is an excellent laboratory for investigating the IMF across the entire mass range of the population, from planetary-mass objects to intermediate/high-mass stars. We combine new deep optical photometry with optical and near-infrared data from the literature to select 1687 member candidates covering a 1.1° radius area in 25 Ori. With this sample we derived the 25 Ori system IMF from 0.012 to 13.1 M⊙. This system IMF is well described by a two-segment power law with Γ = −0.74 ± 0.04 for m < 0.4 M⊙ and Γ = 1.50 ± 0.11 for m ≥ 0.4 M⊙. It is also well described over the whole mass range by a tapered power-law function with Γ = 1.10 ± 0.09, mp = 0.31 ± 0.03 and β = 2.11 ± 0.09. The best lognormal representation of the system IMF has mc = 0.31 ± 0.04 and σ = 0.46 ± 0.05 for m < 1 M⊙. This system IMF does not present significant variations with the radii. We compared the resultant system IMF as well as the brown dwarf/star ratio of 0.16 ± 0.03 that we estimated for 25 Ori with that of other stellar regions with diverse conditions and found no significant discrepancies. These results support the idea that general star-formation mechanisms are probably not strongly dependent on environmental conditions. We found that the substellar and stellar objects in 25 Ori do not have any preferential spatial distributions and confirmed that 25 Ori is a gravitationally unbound stellar association.
Radiative transfer of hydrogen lines from supernova remnant shock waves: contributions of 2s-state hydrogen atoms
Authors: Shimoda Jiro , Laming J Martin
Published: March 2019

Radiative transfer in hydrogen lines in supernova remnant (SNR) shock waves is studied taking into account the population of the hydrogen atom 2s-state. Measurements of Balmer line emission, especially of H α, are often relied on to derive physical conditions in the SNR shock. On the other hand, Lyman series photons, especially Ly β, are mostly absorbed by upstream hydrogen atoms. As a result, atoms are excited to the 3p state, and then emit H α by the spontaneous transition from 3p to 2s. Thus, the nature of H α depends on how many Ly β photons are converted to H α photons. Moreover, the Balmer lines can be scattered by the 2s-state hydrogen atoms, which are excited not only by collisional excitation but also by the Lyman–Balmer conversion. It is shown for example that the H α photons are scattered if the shock propagates into an H i cloud with a density of ∼30 cm−3 and a size of ∼1 pc. We find that the line profile of H α becomes asymmetric resulting from the difference between line centre frequencies among the transitions from 3s to 2p, from 3p to 2s, and from 3d to 2p. We also find that the broad-to-narrow ratio of H α, which is often used to estimate the ion-electron temperature equilibrium, varies at most ≃ 10 per cent depending on the ionization degree of the upstream medium because of incomplete conversion of Lyman lines to Balmer lines.
Chemical analysis of CH stars – III. Atmospheric parameters and elemental abundances
Authors: Purandardas Meenakshi , Goswami Aruna , Goswami Partha Pratim , Shejeelammal J , Masseron Thomas
Published: March 2019

Elemental abundances of CH stars can provide observational constraints for theoretical studies on the nucleosynthesis and evolution of low- and intermediate-mass stars. However, available abundance data in literature are quite scanty. In our pursuit to generate a homogeneous data base of elemental abundances of CH stars we have performed a detailed chemical abundance study for a sample of 12 potential CH star candidates based on high-resolution spectroscopy. We present first time abundance analysis for the objects HE0308–1612, CD−281082, HD30443, and HD87853. For the other objects, although limited information is available, detailed chemical composition studies are missing. Our analysis shows CD−281082 to be a very metal-poor object with [Fe/H] = −2.45 and enriched in carbon with [C/Fe] = 2.19. With a ratio of [Ba/Eu] ∼ 0.02 the star satisfies the classification criteria of a CEMP-r/s star. The objects CD−382151 with [Fe/H] = −2.03 and HD30443 with [Fe/H] ∼ −1.68 are found to show the characteristic properties of CH stars. HE0308–1612 and HD87853 are found to be moderately metal poor with [Fe/H] ∼ −0.73; while HE0308–1612 is moderately enhanced with carbon ([C/Fe] ∼ 0.78) and shows the spectral properties of CH stars, the abundance of carbon could not be estimated for HD87853. Among the two moderately metal-poor objects, HD87080 ([Fe/H] = −0.48) shows near solar carbon abundance, and HD176021 ([Fe/H] = −0.63) is mildly enhanced in carbon with [C/Fe]  = 0.52. HD176021 along with HD202020 a known binary, exhibit the characteristic properties of CH stars as far as the heavy element abundances are concerned. Five objects in our sample show spectral properties that are normally seen in barium stars.
Quasar Sightline and Galaxy Evolution (QSAGE) survey – I. The galaxy environment of O vi absorbers up to z = 1.4 around PKS 0232−04
Authors: Bielby R M , Stott J P , Cullen F , Tripp T M , Burchett J N , Fumagalli M , Morris S L , Tejos N , Crain R A , Bower R G , Prochaska J X
Published: March 2019

We present the first results from a study of O vi absorption around galaxies at z < 1.44 using data from a near-infrared grism spectroscopic Hubble Space Telescope Large Programme, the Quasar Sightline and Galaxy Evolution (QSAGE) survey. QSAGE is the first grism galaxy survey to focus on the circumgalactic medium at z ∼ 1, providing a blind survey of the galaxy population. The galaxy sample is H α flux limited (f(H α) > 2 × 10−17 erg s−1 cm−2) at 0.68 < z < 1.44, corresponding to ≳0.2–0.8 M⊙ yr−1. In this first of 12 fields, we combine the galaxy data with high-resolution STIS and COS spectroscopy of the background quasar to study O vi in the circumgalactic medium. At z ∼ 1, we find O vi absorption systems up to b ∼ 350 kpc (∼4Rvir) from the nearest detected galaxy. Further, we find ${\sim }50{{\ \rm per\ cent}}$ of ≳1 M⊙ yr−1 star-forming galaxies within 2Rvir show no associated O vi absorption to a limit of at least N(O vi) = 1013.9 cm−2. That we detect O vi at such large distances from galaxies and that a significant fraction of star-forming galaxies show no detectable O vi absorption disfavours outflows from ongoing star formation as the primary medium traced by these absorbers. Instead, by combining our own low- and high-redshift data with existing samples, we find tentative evidence for many strong (N(O vi) > 1014 cm−2) O vi absorption systems to be associated with M⋆ ∼ 109.5–10 M⊙ mass galaxies (Mhalo ∼ 1011.5–12 M⊙ dark matter haloes), and infer that they may be tracing predominantly collisionally ionized gas within the haloes of such galaxies.