Neutral Background Research Articles

Three-dimensional cross-field flows at the plasma-material interface in an oblique magnetic field

This article describes experimental evidence that the magnetic presheath is a fully three-dimensional structure modified by ion–neutral collisions. Velocity distributions of both ions and neutrals, obtained via laser-induced fluorescence, show that cross field ion drifts do not result from entrainment of ions in a flowing neutral background. Ion flows parallel to E×B arise and accelerate to as much as 0.2cs within several ion gyroradii of the boundary surface, where cs is the sound speed. Within measurement resolution, the onset of the E×B aligned flow occurs at the same distance to the surface that ions begin to deflect from travel along magnetic field lines. Collisional fluid and particle-in-cell simulations of the boundary region are compared to the experimental measurements. We find that, in contrast to the classical collisionless Chodura model, collisional effects between the ions and the non-flowing neutral population are essential to quantitatively predict the observed ion drift velocities. No momentum coupling between ions and neutrals, separable from noise and other effects, is observed in either signal. We discuss several explanations and implications of this observation.

Application of hue spectra fingerprinting during cold storage and shelf-life of packaged sweet cherry

Presented work investigated the application of a new color analysis technique in post-harvest life of sweet cherry (Prunus avium L. ‘Hudson’). The hue spectra fingerprinting creates a histogram of image colors by summarizing the saturation. The advantage of this calculation method is that vivid colors make peaks while neutral background color is eliminated without object segmentation. Partial Least Squares (PLS) regression was used to estimate reference parameters during 9 d cold storage at 10 ± 0.5 °C (RH = 90 ± 1%) and following 2 d shelf-life at 20 ± 0.5 °C. The reference parameters of respiration, weight loss, fruit firmness and total soluble solid (TSS) content were measured. Samples were split into seven groups according to the number of perforations of polypropylene film and fructose concentration of moisture absorber. It was observed that parameters TSS and fruit firmness were the most sensitive to the length of storage. Weight loss was affected significantly by packaging. All reference parameters were estimated by PLS model with R2 > 0.917, but weight loss and respiration obtained high estimation error of RMSE% = 48.02% and 11.76%, respectively. TSS and fruit firmness prediction were successful with RMSE% = 0.84% and 1.85%, respectively. Desiccation and color change of peduncle became visible in the green range of hue spectra. Color change of red fruit was observed with decreasing saturation in the red range of hue spectra. Our findings suggest that hue spectra fingerprinting can be a useful nondestructive method for monitoring quality change of sweet cherry during post-harvest handling and shelf-life.

Color determination with no-match-templates using two different tooth color scales-An in vitro evaluation.

Visual shade selection is the most commonly used method in dentistry and a challenge for every dentist. However, differences to natural tooth color and the differences of each shade guide are well known. The aim of this paper is to investigate the suitability of two different color scales for determining the color of no-match templates. Volunteers (N = 76) selected a shade color of a no-match template with two shade guides (VITA Classical shade guide (VC) and VITA Linearguide 3D-Master (V3D LG), both Vita Zahnfabrik). The neutral grey background was laterally illuminated with a color differentiation lamp (Dialite, Eickhorst GmbH). For the volunteers' accuracy, the triangle's area was used which are emerge by the color coordinates of a template (LT aT bT ) and the color coordinates of the two decisions (L1 a1 b1 and L2 a2 b2 ). Statistical software was used to evaluate the differences in ΔE00 with α = .01. A deviation in the median of ΔE00 of 7.6 (V3D LG, first choice) to 6.6 (VC, second choice) was detected, while U test showed no significant differences in the median for both color scales. But the triangle's area generated by both shade decisions and tooth color with V3D LG was significant smaller (14.2) then VC (19.2) (P ≤ .001). When comparing both results no significant difference in the subject's shade selection and the shade guides was detected. The new evaluation strategy using the size of the triangle's areas proves the superiority of the V3D LG due to a better distribution of the tooth color shades within the color space.

Block copolymer directed self-assembly defect modes induced by localized errors in chemoepitaxial guiding underlayers: A molecular simulation study

Block copolymer (BCP) directed self-assembly (DSA) has been presented as a potential economically attractive enhancement to extend the capabilities of optical lithography for semiconductor manufacturing. One concern in DSA is the level of defectivity that can be achieved in such a process. Although entropic effects will always lead to some degree of defectivity, highly ordered structures with a low theoretical equilibrium defect density can be produced by guiding the ordering and placement of the BCP domains using a patterned underlayer. Recent experimental studies have shown that while DSA processes can significantly reduce the observed defect density, defectivity levels are generally still higher than allowable for high-volume manufacturing and higher than what would be anticipated from free energy estimates of the observed defect modes. In particular, bridge defects are one of the most commonly observed defect modes in experimental DSA studies. A number of hypotheses have been proposed to explain the origins of these defects. One hypothesis is that so-called affinity defects present in the underlayer can spawn bridge defects in the overlying BCP film. The goal of the work reported here was to investigate the extent to which bridge defects can be generated or further reinforced in lamellae-forming block copolymer films due to affinity defects in the underlayer pattern. Coarse-grained molecular dynamics simulations were used to simulate the chemoepitaxial DSA of monodisperse block copolymer films atop underlayers with varying affinity defect sizes. Affinity defects were simulated by creating circular regions of a single polymer block type (which is the opposite block type of that used to pattern the underlayer guiding stripes) in the nominally neutral background region of the underlayer. These affinity defects were positioned in regions of the underlayer where they were the incorrect type to match the overlying block copolymer pattern. It was observed that the presence of an affinity defect in the neutral region of the underlayer caused the energetically preferential polymer block to wet the affinity defect, thus creating the nucleus of what could potentially become a bridge defect—even when the affinity defects were very small. As the radius of the underlayer affinity defect (RoD) increased, the amount of block copolymer of incorrect type (with respect to a perfectly assembled copolymer pattern) that assembled above the affinity defect increased; but, in general, the thickness of the wetting layer in contact with the affinity defect was only roughly one polymer chain thick. These data suggest that an affinity defect in the underlayer alone is unlikely to be noticeably enhanced by significant bridge defect formation in a monodisperse block copolymer film.

COVID-19-A Guide to Rapid Implementation of Telehealth Services: A Playbook for the Pediatric Gastroenterologist.

COVID-19-A Guide to Rapid Implementation of Telehealth Services: A Playbook for the Pediatric Gastroenterologist.

Response inhibition during processing of sexual stimuli in males with problematic hypersexual behavior.

Background and aimsIndividuals with problematic hypersexual behavior (PHB) are unable to control their sexual cravings, regardless of other situational factors. This inability to control cravings is a common trait in patients with neurological pathologies related to response inhibition. Until recently, however, it was unclear whether individuals with PHB have decreased inhibition and altered neural responses in the brain regions associated with inhibition compared to healthy control individuals, especially in the presence of distracting sexual stimuli. In this study, we examined the neural and psychological underpinnings of inhibition in individuals with PHB.MethodsThirty individuals with PHB and 30 healthy subjects underwent functional magnetic resonance imaging while performing a modified go/no-go task with neutral or sexual backgrounds used as distractors.ResultsIndividuals with PHB showed poorer response inhibition than healthy subjects, especially when sexual distractors were present. Further, compared to healthy control subjects, individuals with PHB showed decreased activation in the right inferior frontal gyrus (IFG) and reduced functional connectivity between the IFG and the pre-supplementary motor area (preSMA) when response inhibition was required. Finally, the reduced activation and connectivity were more pronounced in the presence of sexual distractors than in the presence of neutral distractors.DiscussionThese findings suggest that individuals with PHB show reduced ability to inhibit responses that might be related to lower IFG activation and IFG-preSMA connectivity during response inhibition. Our results provide insights into the neurobiological underpinnings of poor response inhibition in individuals with PHB.

Vācbaltiešu un latviešu attiecību attēlojums Rūdolfa Blaumaņa daiļradē

The article explores the relationship between Baltic Germans and Latvians in the works of Rūdolfs Blaumanis by turning attention towards the interpretation of this topic within the context of the social history of literature. An insight into previous evaluations by literary historians has been provided. In the first part of the article, two works with central Baltic German characters – novella “Andriksons” (1899) and play “Ugunī” (In the Fire, 1906, written in 1904) – have been analyzed. In these works, German landowners have been depicted demonstrating the social and national conflicts of the age in their relationship with subordinated Latvians. The characters of landowners are ambiguous and indecisive, and they are distanced from everyday reality and living in the past. Their communication with Latvians is characterized by complications and obstacles. Hence, these characters can be viewed as a wider generalization about the crisis of the Baltic German community by the turn of the 20th century. In the second part of the article, episodic characters of Baltic Germans in prose fiction have been explored along with the overview of satirical poetry by Blaumanis in which the relationship between Baltic Germans and Latvians mostly in the period after the revolution of 1905 has been addressed. It has been concluded in the article that in the representations of the relationship between Baltic Germans and Latvians, Blaumanis depicts the instability of the transition period and avoids disclosing his own views. This corresponds to his concept of the depiction of social problems in literary works. Satirical poetry, which is less neutral but also less literary successful, remains an exception. Baltic German characters in works of Blaumanis are mostly episodic, and besides neutral background characters and politically charged characters in satirical poetry, the most interesting both literary and historically are the characters in which the contradictions of the period have been represented.

Affect enhances object-background associations: evidence from behaviour and mathematical modelling

ABSTRACT In recognition memory paradigms, emotional details are often recognised better than neutral ones, but at the cost of memory for peripheral details. We previously provided evidence that, when peripheral details must be recalled using central details as cues, peripheral details from emotional scenes are at least as likely to be recalled as those from neutral scenes. Here we replicated and explicated this result by implementing a mathematical modelling approach to disambiguate the influence of target type, scene emotionality, scene valence, and their interactions. After incidentally encoding scenes that included neutral backgrounds with a positive, negative, or neutral foreground objects, participants showed equal or better cued recall of components from emotional scenes compared to neutral scenes. There was no evidence of emotion-based impairment in cued recall in either of two experiments, including one in which we replicated the emotion-induced memory trade-off in recognition. Mathematical model fits indicated that the emotionality of the encoded scene was the primary driver of improved cued-recall performance. Thus, even when emotion impairs recognition of peripheral components of scenes, it can preserve the ability to recall which scene components were studied together.

The Personality Influence Factors of Ecological Microexpressions Recognition and Natural Exposure Training Effect: Openness, Depression and Gender

With the in-depth exploration of emotion, criminal investigation and other fields, the research on microexpressions has become one of the hot topics. In the current study, it was the first time to explore the influence factors of the recognition and natural exposure training of ecological microexpressions (i.e. microexpressions under different expressions backgrounds). A total of 87 (45 males and 42 female) undergraduates and postgraduates from Soochow University were randomly selected to participate in the research. This study used the microexpressions data of EMERT, except that the openness subscale and the Beck Depression Inventory was measured for the same participants. It was found that: (1) Openness was positively correlated with some ecological micro-expression recognition, and was positively or negatively correlated with the natural exposure training effect, but was not correlated with the training effect of any micro-expression recognition under neutral backgrounds. (2) The Baker's depression degree was positively correlated with some negative microexpressions recognition, and was positively correlated with disgust under fear training, and was negatively correlated with some fear microexpressions recognition training. (3) The recognition of disgust under sadness and training effect of fear under surprise of women were significantly higher than those of men, but the recognition of surprise under sadness and training effect of disgust under neutral of women were less than those of men.

Finom textil, téglából = Fine Textiled Brick

When designing a museum the main challenge is to create a neutral background upon which artefacts and artworks might be presented which is made easier when the nature of the exhibits is known, items of clothing, accessories and drawings all created by the same hand: therefore the real challenge lays with how to dress the museums exterior. Rising from stone at pavement level, passing over a concrete belt up towards decorative brickwork which has been treated more in like a textile than a construction material creating a play on light and form indicative of the works of Yves Saint Laurent.

Characterization of electrostatic discharge induced plasmas in dielectrics irradiated by multi-MeV electron beam

This work is devoted to experimental analyses of plasmas induced by electrostatic discharges in dielectric materials. Electrostatic discharges are produced in polytetrafluoroethylene (Teflon) and polyethylene samples irradiated by a 6-MeV electron beam generated by a linear accelerator facility. The time and space evolution of the conductivity of the plasma is determined by microwave transmission measurements across a cavity followed by comparison with 3D Maxwell calculations. Furthermore, plasma parameters such as average electron energies and densities of electrons and neutral background species are determined from a 0D collisional radiative model. This analysis infers a plasma expansion velocity of about 150 km/s and a maximum electric conductivity of about 40 S/m. The electron density is estimated to be about 1012 cm−3, and electron average energies are up to 60 eV, while neutral species densities do not exceed 1018 cm−3.

The impact of genetic adaptation on chimpanzee subspecies differentiation.

Chimpanzees, humans' closest relatives, are in danger of extinction. Aside from direct human impacts such as hunting and habitat destruction, a key threat is transmissible disease. As humans continue to encroach upon their habitats, which shrink in size and grow in density, the risk of inter-population and cross-species viral transmission increases, a point dramatically made in the reverse with the global HIV/AIDS pandemic. Inhabiting central Africa, the four subspecies of chimpanzees differ in demographic history and geographical range, and are likely differentially adapted to their particular local environments. To quantitatively explore genetic adaptation, we investigated the genic enrichment for SNPs highly differentiated between chimpanzee subspecies. Previous analyses of such patterns in human populations exhibited limited evidence of adaptation. In contrast, chimpanzees show evidence of recent positive selection, with differences among subspecies. Specifically, we observe strong evidence of recent selection in eastern chimpanzees, with highly differentiated SNPs being uniquely enriched in genic sites in a way that is expected under recent adaptation but not under neutral evolution or background selection. These sites are enriched for genes involved in immune responses to pathogens, and for genes inferred to differentiate the immune response to infection by simian immunodeficiency virus (SIV) in natural vs. non-natural host species. Conversely, central chimpanzees exhibit an enrichment of signatures of positive selection only at cytokine receptors, due to selective sweeps in CCR3, CCR9 and CXCR6 -paralogs of CCR5 and CXCR4, the two major receptors utilized by HIV to enter human cells. Thus, our results suggest that positive selection has contributed to the genetic and phenotypic differentiation of chimpanzee subspecies, and that viruses likely play a predominate role in this differentiation, with SIV being a likely selective agent. Interestingly, our results suggest that SIV has elicited distinctive adaptive responses in these two chimpanzee subspecies.

Metameric effects on peridot by changing background color.

Peridot's yellowish-green color is not only produced by ${{\rm Fe}^{2+}}$Fe2+ but is also influenced by background, observer, illuminance, and color temperature of the light source. In this research, we studied the most effective background for peridot color grading under a 6504K fluorescent lamp. Ninety-five gem-quality peridot samples from China, Pakistan, and Myanmar were studied using electron probe micro-analyzer, spectrophotometer, Munsell neutral gray backgrounds, and standard gold alloy backgrounds. The results provided the color effects of 24K, 22K, 20K, 18K, and 16K gold alloy backgrounds and Munsell neutral gray backgrounds on the peridot's color. It was found that the Munsell N9 background seems to be the most effective background for peridot color grading. Using the Munsell N9 background, peridot colors were graded into three levels from good to bad: Fancy Intense, Fancy Deep, and Fancy by using K-means clustering analysis and Fisher discriminant analysis methods. The peridot's color level reverse phenomenon should be considered when the background varies between Munsell N7 and N9 gray.

Impact of the starting point chromaticity on memory color matching accuracy.

In this study, the impact of starting point chromaticity and number of observers on memory color matching results was investigated. Matching data were obtained for 3 objects (neutral grey cube, yellow lemon and green apple) under a neutral white and a yellow background illumination. Memory color matchings were made for ten starting points of which eight chromaticities were symmetrically distributed along the hue circle and centered at the equal energy white (EEW) chromaticity of the neutral white background illumination; one starting point at the EEW chromaticity and one with the same chromaticity as the background. The matching track from starting point to the memory matched chromaticity was also recorded. It did not tend to cross over the central region towards the complementary hue, especially for experienced observers. The results also demonstrated a significant starting point bias, whereby the matched chromaticities were biased towards the chromaticity of the starting point. Starting point bias can be minimized by selecting three starting points symmetrically distributed around the expected memory color chromaticity. Furthermore, at least, ten observers are needed to achieve stable results for the grey cube and yellow lemon. For the green apple, the results are less conclusive and around 40 observers would be needed to obtain a stable average estimate for the chromaticity of the memory color. The large inter-observer variation may result from cultural differences or from natural variations in the "green" apple appearance. This study provides a well-founded guidance for future application of the memory color matching method.

Short-Distance Symmetry of Pair Correlations in Two-Dimensional Jellium

We consider the two-dimensional one-component plasma (jellium) of mobile pointlike particles with the same charge $e$, interacting pairwisely by the logarithmic Coulomb potential and immersed in a fixed neutralizing background charge density. Particles are in thermal equilibrium at the inverse temperature $\beta$, the only relevant dimensionless parameter is the coupling constant $\Gamma\equiv\beta e^2$. In the bulk fluid regime and for any value of the coupling constant $\Gamma=2\times{\rm integer}$, \v{S}amaj and Percus [J. Stat. Phys. {\bf 80}, 811--824 (1995)] have derived an infinite sequence of sum rules for the coefficients of the short-distance expansion of particle pair correlation function. In the context of the equivalent fractional quantum Hall effect, by using specific methods of quantum geometry Haldane [PRL {\bf 107}, 116801 (2011) and arXiv:1112.0990v2] derived a self-dual relation for the Landau-level guiding-center structure factor. In this paper, we establish the relation between the guiding-center structure factor and the pair correlation function of jellium particles. It is shown that the self-dual formula, which provides an exact relation between the pair correlation function and its Fourier component, comes directly from the short-distance symmetry of the bulk jellium. The short-distant symmetry of pair correlations is extended to the semi-infinite geometry of a rectilinear plain hard wall with a fixed surface charge density, constraining particles to a half-space. The symmetry is derived for the original jellium model as well as its simplified version with no background charge (charged wall surface with ``counter-ions only''). The obtained results are checked at the exactly solvable free-fermion coupling $\Gamma=2$.

Traveling Ionosphere Disturbance Signatures on Ground‐Based Observations of the O(1D) Nightglow Inferred From 1‐D Modeling

AbstractThis paper reports our simulations of the volume emission rate of the O(1D) redline nightglow perturbed by waves traveling across the thermosphere at around 250 km altitude. Waves perturb the electronic and neutral background densities and temperatures in the region and modify the O(1D) layer intensity as it is captured by ground‐based nightglow instruments. The changes in the integrated volume emission rate are calculated for various vertical wavelengths of the perturbations. We demonstrate that, as the solar activity intensifies, the vertical scales of most likely observable TID waves become larger. For high solar activity, we demonstrate that only waves presenting vertical wavelengths larger than 360 km are likely to be observed. The variation of the range of likely observable vertical wavelengths with the solar cycle offers a plausible explanation for the low occurrence rate of TID in measurements of the redline nightglow during high solar activity periods. We have compared our results with those of Negale et al. (2018; https://doi.org/10.1029/2017JA024876) and Paulino et al (2018; https://doi.org/10.5194/angeo-36-265-2018) to verify that observed vertical wavelengths distribute around 140–210 km, in good correspondence with our predicted threshold wavelength 160 km for very low solar cycle period.

Short- and long-range contributions to equilibrium and transport properties of solid electrolytes

Condensed ionic systems are described in the framework of a combined approach that takes into account both long-range and short-range interactions. Short-range interaction is expressed in terms of mean potentials and long-range interaction is considered in terms of screening potentials. A system of integral equations for these potentials is constructed based on the condition of the best agreement of the system of study with the reference system. In contrast to the description of media with short-range interactions, in this text the reference distribution includes not only the field of mean potentials but also Coulomb interaction between particles. A one-component system made of ions in a neutralizing background of fixed counterions is considered. The model can be used to describe solid ionic conductors. In order to study the movement of cations on the sites of their sub-lattice, the lattice approximation of the theory is employed based on the calculation of the pair distribution function. Using the collective variables approach, a technique improving the starting expression for this function is proposed. Notably, the neglected terms in the expansion of this function are approximated by single-particle terms ensuring that the normalization condition is satisfied. As a result, the applicability of the theory is extended to a wide region of thermodynamic parameters. The chemical potential and the diffusion coefficient are calculated showing the possibility of phase transitions characteristic of the system.

Dispersion properties of electron acoustic waves in degenerate and non‐degenerate quantum plasmas

AbstractThe longitudinal response functions are used to generalize the dispersion properties of electron acoustic waves (EAWs) in the presence of quantum recoil, for isotropic, non‐relativistic, degenerate/non‐degenerate plasmas. In order to study the EAWs, the constituents of non‐degenerate (thermal) plasma are considered to be of two groups of electrons having different number density and temperature, namely the cold electrons and the hot electrons. Similarly in degenerate (Fermi) plasma the two population of electrons are considered to be the thinly populated and the thickly populated electrons. The sparsely populated electrons are termed as cold electrons while the densely populated ones are termed as hot electrons. The ions are stationary which form the neutralizing background. The absorption coefficients for Landau damping with the inclusion of the quantum recoil in both plasmas are calculated and discussed. The results are discussed in the context of laser‐produced plasma.

Age differences in the relationship between cortisol and emotional memory.

Research has shown that remembering emotional information can occur at the expense of surrounding neutral background information; this emotional memory trade-off occurs similarly in both younger and older adults. We investigated how levels of cortisol, a hormone that acts on the central nervous system, impact emotional memory with age. Younger and older adult participants incidentally encoded emotional (positive, negative, or neutral) items placed on neutral backgrounds and later completed recognition tests for both the items and the backgrounds. Cortisol was measured at multiple time points to assess basal cortisol. Results are reported for prelearning levels, as findings were comparable across time points. Results revealed that higher levels of cortisol predicted a lower memory trade-off effect for older adults compared to younger adults and that this age difference in the role of cortisol tended to be strongest for memory for negative items (rather than for backgrounds or neutral items). No such interaction emerged for the positive trade-off effect. These results suggest that cortisol levels play a different role in supporting emotional memory across the life span, with lower levels of cortisol potentially more adaptive for memory for negative emotional information and higher levels indicating potential impairment with age. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Reward and avoidance learning in the context of aversive environments and possible implications for depressive symptoms

BackgroundAversive stimuli in the environment influence human actions. This includes valence-dependent influences on action selection, e.g., increased avoidance but decreased approach behavior. However, it is yet unclear how aversive stimuli interact with complex learning and decision-making in the reward and avoidance domain. Moreover, the underlying computational mechanisms of these decision-making biases are unknown.MethodsTo elucidate these mechanisms, 54 healthy young male subjects performed a two-step sequential decision-making task, which allows to computationally model different aspects of learning, e.g., model-free, habitual, and model-based, goal-directed learning. We used a within-subject design, crossing task valence (reward vs. punishment learning) with emotional context (aversive vs. neutral background stimuli). We analyzed choice data, applied a computational model, and performed simulations.ResultsWhereas model-based learning was not affected, aversive stimuli interacted with model-free learning in a way that depended on task valence. Thus, aversive stimuli increased model-free avoidance learning but decreased model-free reward learning. The computational model confirmed this effect: the parameter lambda that indicates the influence of reward prediction errors on decision values was increased in the punishment condition but decreased in the reward condition when aversive stimuli were present. Further, by using the inferred computational parameters to simulate choice data, our effects were captured. Exploratory analyses revealed that the observed biases were associated with subclinical depressive symptoms.ConclusionOur data show that aversive environmental stimuli affect complex learning and decision-making, which depends on task valence. Further, we provide a model of the underlying computations of this affective modulation. Finally, our finding of increased decision-making biases in subjects reporting subclinical depressive symptoms matches recent reports of amplified Pavlovian influences on action selection in depression and suggests a potential vulnerability factor for mood disorders. We discuss our findings in the light of the involvement of the neuromodulators serotonin and dopamine.