Miracle-dz/UniFAR-FTUs huggingface dataset:
Phase-space structures – I. A comparison of 6D density estimators

In the framework of particle-based Vlasov systems, this paper reviews and analyses different methods recently proposed in the literature to identify neighbours in 6D space and estimate the corresponding phase-space density. Specifically, it compares smoothed particle hydrodynamics (SPH) methods based on tree partitioning to 6D Delaunay tessellation. This comparison is carried out on statistical and dynamical realizations of single halo profiles, paying particular attention to the unknown scaling, SG, used to relate the spatial dimensions to the velocity dimensions. It is found that, in practice, the methods with local adaptive metric provide the best phase-space estimators. They make use of a Shannon entropy criterion combined with a binary tree partitioning and with subsequent SPH interpolation using 10–40 nearest neighbours. We note that the local scaling SG implemented by such methods, which enforces local isotropy of the distribution function, can vary by about one order of magnitude in different regions within the system. It presents a bimodal distribution, in which one component is dominated by the main part of the halo and the other one is dominated by the substructures of the halo. While potentially better than SPH techniques, since it yields an optimal estimate of the local softening volume (and therefore the local number of neighbours required to perform the interpolation), the Delaunay tessellation in fact generally poorly estimates the phase-space distribution function. Indeed, it requires, prior to its implementation, the choice of a global scaling SG. We propose two simple but efficient methods to estimate SG that yield a good global compromise. However, the Delaunay interpolation still remains quite sensitive to local anisotropies in the distribution. To emphasize the advantages of 6D analysis versus traditional 3D analysis, we also compare realistic 6D phase-space density estimation with the proxy proposed earlier in the literature, Q=ρ/σ3, where ρ is the local 3D (projected) density and 3σ2 is the local 3D velocity dispersion. We show that Q only corresponds to a rough approximation of the true phase-space density, and is not able to capture all the details of the distribution in phase space, ignoring, in particular, filamentation and tidal streams.
Understanding the mechanism for response selection in compatibility tasks: Referential coding contrasted with biological properties of the hands

Murchison, Nicole M. Ph.D., Purdue University, August 2016. Understanding the Mechanism for Response Selection in Compatibility Tasks: Referential Coding Contrasted with Biological Properties of the Hands. Major Professor: Robert W. Proctor Several researchers have hypothesized that the hands have unique effects on visual attentional resources and performance in response-selection tasks. This hand-specific processing hypothesis – that biological properties of the hands/palms uniquely affect visual attention and response selection – can be compared to a referential object coding hypothesis – that objects are coded in relation to other salient objects – favored in explanations of many compatibility effects. To test implications of these accounts, and specific effects that the hands (or general referential objects) have on attentional prioritization, I had participants perform three compatibility tasks using the hands or wooden blocks as referential objects. These objects were placed on a display screen such that they meaningfully segmented the space appropriate to response selection or in a position below the screen where they did not segment the space. Participants responded with a left or right foot-press response in all tasks, so that position of the response effectors was not confounded with that of the hands. The Simon task evaluated whether hands differently affected the processes of selecting the correct response when the task was stimulus-property dependent: That is
In Vivo Selection To Identify Bacterial Strains with Enhanced Ecological Performance in Synbiotic Applications

ABSTRACT One strategy for enhancing the establishment of probiotic bacteria in the human intestinal tract is via the parallel administration of a prebiotic, which is referred to as a synbiotic. Here we present a novel method that allows a rational selection of putative probiotic strains to be used in synbiotic applications: in vivo selection (IVS). This method consists of isolating candidate probiotic strains from fecal samples following enrichment with the respective prebiotic. To test the potential of IVS, we isolated bifidobacteria from human subjects who consumed increasing doses of galactooligosaccharides (GOS) for 9 weeks. A retrospective analysis of the fecal microbiota of one subject revealed an 8-fold enrichment in Bifidobacterium adolescentis strain IVS-1 during GOS administration. The functionality of GOS to support the establishment of IVS-1 in the gastrointestinal tract was then evaluated in rats administered the bacterial strain alone, the prebiotic alone, or the synbiotic combination. Strain-specific quantitative real-time PCR showed that the addition of GOS increased B. adolescentis IVS-1 abundance in the distal intestine by nearly 2 logs compared to rats receiving only the probiotic. Illumina 16S rRNA sequencing not only confirmed the increased establishment of IVS-1 in the intestine but also revealed that the strain was able to outcompete the resident Bifidobacterium population when provided with GOS. In conclusion, this study demonstrated that IVS can be used to successfully formulate a synergistic synbiotic that can substantially enhance the establishment and competitiveness of a putative probiotic strain in the gastrointestinal tract.
Evolution of Chemistry and Molecular Line Profiles during Protostellar Collapse

Understanding the chemical evolution in star-forming cores is a necessary precondition to correctly assessing physical conditions when using molecular emission. We follow the evolution of chemistry and molecular line profiles through the entire star formation process, including a self-consistent treatment of dynamics, dust continuum radiative transfer, gas energetics, chemistry, molecular excitation, and line radiative transfer. In particular, the chemical code follows a gas parcel as it falls toward the center, passing through regimes of density, dust temperature, and gas temperature that are changing because of both the motion of the parcel and the evolving luminosity of the central source. We combine a sequence of Bonnor-Ebert spheres and the inside-out collapse model to describe dynamics from the pre-protostellar stage to later stages. The overall structures of abundance profiles show complex behavior that can be understood as interactions between freezeout and evaporation of molecules. We find that the presence or absence of gas-phase CO has a tremendous effect on the less abundant species. In addition, the ambient radiation field and the grain properties have important effects on the chemical evolution, and the variations in abundance have strong effects on the predicted emission-line profiles. Multitransition and multiposition observations are necessary to constrain the parameters and interpret observations correctly in terms of physical conditions. Good spatial and spectral resolution is also important in distinguishing evolutionary stages.
Dark energy in a hyperbolic universe

Dark energy models arising from a slowly evolving scalar (quintessence) field Φ are studied for various potentials V(Φ) in a universe with negative curvature. The potentials differ in whether they possess a minimum at Φ = 0 or are monotonically declining, i.e. have a minimum at infinity. The angular power spectrum C l of the cosmic microwave background (CMB) and the magnitude-redshift relation m B (z) of the type Ia supernovae are compared with those of the quintessence models. It is demonstrated that some of the models with Ω t o t ≃ 0.85-0.9 are in agreement with the observations, i.e. possess acoustic peaks in the angular power spectrum of the CMB anisotropy as observed experimentally, and yield a magnitude-redshift relation in agreement with the data. Furthermore, it is found that the power spectrum P(k) of the large-scale structure (LSS) also agrees with the observations.
Computers in Human Behavior

Learning styles which refer to students’ preferred ways to learn can play an important role in adaptive e-learning systems. With the knowledge of different styles, the system can offer valuable advice and instructions to students and teachers to optimise students’ learning process. Moreover, e-leaning system which allows computerised and statistical algorithms opens the opportunity to overcome drawbacks of the traditional detection method that uses mainly questionnaire. These appealing reasons have led to a growing number of researches looking into the integration of learning styles and adaptive learning system. This paper, by reviewing 51 studies, delves deeply into different parts of the integration process. It captures a variety of aspects from learning styles theories selection in e-learning environment, online learning styles predictors, automatic learning styles classiﬁcation to numerous learning styles applications. The results offer insights into different developments, achievements and open problems in the ﬁeld. Based on these ﬁndings, the paper also provides discussion, recommendations and guidelines for future researches.
Keyword Management Costs and "Broad Match" in Sponsored Search Advertising

In sponsored search advertising, advertisers bid to be displayed in response to a keyword search. The operational activities associated with participating in an auction, i.e., submitting the bid and the ad copy, customizing bids and ad copies based on various factors (such as the geographical region from which the query originated, the time of day and the season, the characteristics of the searcher), and continuously measuring outcomes, involve considerable effort. We call the costs that arise from such activities keyword management costs . To reduce these costs and increase advertisers’ participation in keyword auctions, search engines offer an opt-in tool called broad match with automatic and flexible bidding , wherein the search engine automatically places bids on behalf of the advertisers and takes over the above activities as well. The bids are based on the search engine’s estimates of the advertisers’ valuations and, therefore, may be less accurate than the bids the advertisers would have turned in themselves. Using a game-theoretic model, we examine the strategic role of keyword management costs, and of broad match, in sponsored search advertising. We show that because these costs inhibit participation by advertisers in keyword auctions, the search engine has to reduce the reserve price, which reduces the search engine’s profits. This motivates the search engine to offer broad match as a tool to reduce keyword management costs. If the accuracy of broad match bids is sufficiently high, advertisers adopt broad match and benefit from the cost reduction, whereas if the accuracy is very low, advertisers do not use it. Interestingly, at moderate levels of bid accuracy, advertisers individually find it attractive to reduce costs by using broad match, but competing advertisers also adopt broad match and the increased competition hurts all advertisers’ profits, thus creating a “prisoner’s dilemma. ” When advertisers adopt broad match, search engine profits increase. It therefore seems natural to expect that the search engine will be motivated to improve broad match accuracy. Our analysis shows that the search engine will increase broad match accuracy up to the point where advertisers choose broad match, but that increasing the accuracy any further reduces the search engine’s profits.
Long-Term Test-Retest Reliability of Resting-State Networks in Healthy Elderly Subjects and Mild Cognitive Impairment

The investigation of cerebral resting-state networks (RSNs) by functional magnetic resonance imaging (fMRI) is a promising tool for the early diagnosis and follow-up of neuropsychiatric and neurodegenerative disorders like Alzheimer's disease (AD). In this context, the determination of inter-session reliability of these networks is crucial. However, data on network reliability in healthy elderly subjects is rare and does not exist for patients with amnestic mild cognitive impairment (aMCI), a prodromal stage of AD. Therefore, the aim of this study was to investigate the long-term test-retest reliability of RSNs in both groups. Twelve healthy controls (HC) and 13 aMCI patients underwent resting-state fMRI and neuropsychological testing (CERAD test battery) twice, at baseline and after 13-16 months. Resting-state fMRI data was decomposed into independent components using independent component analysis. Inter-session test-retest reliability of the resulting RSNs was determined by calculating voxel-wise intra-class correlation coefficients. Overall test-retest reliability of corresponding RSNs was moderate to high in both groups, but significantly higher in the HC group compared to the aMCI group (p < 0.001), while the cognitive performance within the CERAD test battery remained stable over time in either group. Most reliable RSNs derived from the HC group and were associated with sensory and motor as well as higher order cognitive and the default-mode function. Particularly low reliability was found in basal frontal regions, which are known to be prone to susceptibility-induced noise. We conclude that stable RSNs may represent healthy aging, whereas decreased RSN reliability may indicate progressive neuro-functional alterations before the actual manifestation of clinical symptoms. 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
The Influence of Big Five Personality Traits and Self-efficacy on Entrepreneurial Intention: The Role of Gender

Abstract This study attempts to investigate the influence of the Big Five personality traits and self-efficacy (SE) on entrepreneurial intentions. It also aims to find out whether the influence of a set of personality traits and SE on entrepreneurial intention differs across gender. The target population of this study was students enrolled in Bachelor of Technology (BTech). The results offer support for the relation of openness, neuroticism, conscientiousness and agreeableness, and SE with entrepreneurial intention—except on the relation of extraversion and entrepreneurial intention. Based on the findings, the study argues that the relationship between entrepreneurial intention and Big Five personality traits is moderated, at least partially, by gender.
The Number of Synaptic Inputs and the Synchrony of Large, Sparse Neuronal Networks

The prevalence of coherent oscillations in various frequency ranges in the central nervous system raises the question of the mechanisms that synchronize large populations of neurons. We study synchronization in models of large networks of spiking neurons with random sparse connectivity. Synchrony occurs only when the average number of synapses, M, that a cell receives is larger than a critical value, Mc. Below Mc, the system is in an asynchronous state. In the limit of weak coupling, assuming identical neurons, we reduce the model to a system of phase oscillators that are coupled via an effective interaction, . In this framework, we develop an approximate theory for sparse networks of identical neurons to estimate Mc analytically from the Fourier coefficients of . Our approach relies on the assumption that the dynamics of a neuron depend mainly on the number of cells that are presynaptic to it. We apply this theory to compute Mc for a model of inhibitory networks of integrate-and-fire (I&F) neurons as a function of the intrinsic neuronal properties (e.g., the refractory period Tr), the synaptic time constants, and the strength of the external stimulus, Iext. The number Mc is found to be nonmonotonous with the strength of Iext. For Tr 0, we estimate the minimum value of Mc over all the parameters of the model to be 363.8. Above Mc, the neurons tend to fire in smeared one-cluster states at high firing rates and smeared two-or-more-cluster states at low firing rates. Refractoriness decreases Mc at intermediate and high firing rates. These results are compared to numerical simulations. We show numerically that systems with different sizes, N, behave in the same way provided the connectivity, M, is such that 1/Meff 1/M 1/N remains constant when N varies. This allows extrapolating the large N behavior of a network from numerical simulations of networks of relatively small sizes (N = 800 in our case). We find that our theory predicts with remarkable accuracy the value of Mc and the patterns of synchrony above Mc, provided the synaptic coupling is not too large. We also study the strong coupling regime of inhibitory sparse networks. All of our simulations demonstrate that increasing the coupling strength reduces the level of synchrony of the neuronal activity. Above a critical coupling strength, the network activity is asynchronous. We point out a fundamental limitation for the mechanisms of synchrony relying on inhibition alone, if heterogeneities in the intrinsic properties of the neurons and spatial fluctuations in the external input are also taken into account.
Multi-Functional Roles of Chitosan as a Potential Protective Agent against Obesity

Chitosan, a natural polysaccharide comprising copolymers of glucosamine and N-acetylglucosamine, has been shown to have anti-obesity properties. Two experiments (Exp. 1 and Exp. 2) were performed to determine the role of chitosan on dietary intake, body weight gain, and fat deposition in a pig model, as well as identifying potential mechanisms underlying the anti-obesity effect of chitosan. In Exp. 1, the nutrient digestibility experiment, 16 pigs (n = 4/treatment) were randomly allocated to one of four dietary treatments as follows: 1) basal diet; 2) basal diet plus 300 ppm chitosan; 3) basal diet plus 600 ppm chitosan; 4) basal diet plus 1200 ppm chitosan. The main observation was that crude fat digestibility was lower in the 1200 ppm chitosan group when compared with the control group (P<0.05). In Exp. 2, a total of 80 pigs (n = 20/treatment) were offered identical dietary treatments to that offered to animals in Exp. 1. Blood samples were collected on day 0, day 35 and at the end of the experiment (day 57). Animals offered diets containing 1200 ppm chitosan had a lower daily dietary intake (P<0.001) and body weight gain (P<0.001) from day 35 to 57 when compared with all the other treatment groups. Animals offered diets containing 1200 ppm chitosan had a significantly lower final body weight (P<0.01) when compared with all the other treatment groups. The decreased dietary intake observed in the 1200 ppm chitosan group was associated with increased serum leptin concentrations (P<0.001) and a decrease in serum C-reactive protein (CRP) concentrations (P<0.05). In conclusion, the results of this study highlight novel endocrine mechanisms involving the modulation of serum leptin and CRP concentrations by which chitosan exhibits anti-obesity properties in vivo.
SN 1986J VLBI: The Evolution and Deceleration of the Complex Source and a Search for a Pulsar Nebula

We report on VLBI observations of supernova 1986J in the spiral galaxy NGC 891 at two new epochs, 1990 July and 1999 February, t = 7.4 and 15.9 yr after the explosion, respectively, and on a comprehensive analysis of these and earlier observations from t ~ 4 yr after the explosion date, which we estimate to be 1983.2 ± 1.1. The source is a shell or composite and continues to show a complex morphology with large brightness modulations along the ridge and with protrusions. The supernova is moderately to strongly decelerated. The average outer radius expands as t0.71±0.11, and the expansion velocity has slowed to 6000 km s-1 at t = 15.9 yr from an extrapolated 20,000 km s-1 at t = 0.25 yr. The structure changes significantly with time, showing that the evolution is not self-similar. The shell structure is best visible at the latest epoch, when the protrusions have diminished somewhat in prominence and a new, compact component has appeared. The radio spectrum shows a clear inversion above 10 GHz. This might be related to a pulsar nebula becoming visible through the debris of the explosion. The radio flux density between 1.5 and 23 GHz decreases strongly with time, with the flux density ∝t-2.94±0.24 between t ~ 15 and 19 yr. This decrease is much more rapid than that found in earlier measurements up to t ~ 6 yr.
The Roles of Resilience and Perceived Discrimination in Sexual Minority Identity Integration

The Roles of Resilience and Perceived Discrimination in Sexual Minority Identity Integration Peter Alexander Brown Although researchers and theorists have long moved away from public disclosure of sexual minority identity (i.e. coming out) as the theoretical apex of lesbian, gay, or bisexual (LGB) identity development, it is still considered an important process of overall identity integration. Unfortunately public disclosure of sexual minority identity may be dependent upon the social environment in which disclosure occurs. Given the variable nature of social contexts, public disclosure across domains of social functioning may be problematic. Previous research has suggested that disclosure is in part more or less likely to occur based on individual appraisal of discriminative experiences (Meyer, 2013). The purpose of the present study was to extend this research by establishing a moderating effect of resilience that may help buffer against the experience of discrimination in predicting identity integration. Respondents (n = 250) completed an online survey examining areas of outness, resilience, effect and frequency of perceived discrimination (EPD and FPD), and LGB identity status. Hierarchical regression results indicated that while resilience does not moderate EPD and FPD in predicting degree of outness, along with FPD it does independently predict outness. Additionally, post hoc regression analyses suggested variable predictive ability depending on demographic variables. Implications, limitations and future directions for these findings are discussed.
Bone Mineral Density and Vitamin D Status Among African American Children With Forearm Fractures

OBJECTIVE: To determine whether African American children with forearm fractures have decreased bone mineral density and an increased prevalence of vitamin D deficiency (serum 25-hydroxyvitamin D level ≤20 ng/mL) compared with fracture-free control patients. METHODS: This case-control study in African American children, aged 5 to 9 years, included case patients with forearm fracture and control patients without fracture. Evaluation included measurement of bone mineral density and serum 25-hydroxyvitamin D level. Univariable and multivariable analyses were used to test for associations between fracture status and 2 measures of bone health (bone mineral density and 25-hydroxyvitamin D level) while controlling for other potential confounders. RESULTS: The final sample included 76 case and 74 control patients. There were no significant differences between case and control patients in age, gender, parental education level, enrollment season, outdoor play time, height, or mean dietary calcium nutrient density. Cases were more likely than control patients to be overweight (49.3% vs 31.4%, P = .03). Compared with control patients, case patients had lower whole body z scores for bone mineral density (0.62 ± 0.96 vs 0.98 ± 1.09; adjusted odds ratio 0.38 [0.20–0.72]) and were more likely to be vitamin D deficient (47.1% vs 40.8%; adjusted odds ratio 3.46 [1.09–10.94]). CONCLUSIONS: These data support an association of lower bone mineral density and vitamin D deficiency with increased odds of forearm fracture among African American children. Because suboptimal childhood bone health also negatively impacts adult bone health, interventions to increase bone mineral density and correct vitamin D deficiency are indicated in this population to provide short-term and long-term benefits.