Miracle-dz/UniFAR-FTUs huggingface dataset:
Numerical study of dynamical friction with thermal effects – I. Comparison to linear theory

We investigate by means of numerical simulations with nested Cartesian meshes the force exerted on a massive and luminous perturber moving at constant speed through a homogeneous and opaque gas, taking into account thermal diffusion in the gas and the radiative feedback from the perturber. The force arising from the release of energy into the ambient medium by the perturber, or heating force, is directed along the direction of motion and induces an acceleration of the perturber. Its value is compared to analytic estimates in the low and high Mach number limits, and found to match those accurately. In addition, the drag exerted on a non-luminous perturber significantly departs from the adiabatic expression when thermal diffusion is taken into account. In the limit of a vanishing velocity, this drag tends to a finite value which we determine using linear perturbation theory and corroborate with numerical simulations. The drag on a non-luminous perturber in a non-adiabatic gas therefore behaves like dry or solid friction. We work out the luminosity threshold to get a net acceleration of the perturber and find it to be generally much smaller than the luminosity of accreting low-mass planetary embryos embedded in a gaseous protoplanetary disc at a few astronomical units. We also present in some detail our implementation of nested meshes, which runs in parallel over several \emph{Graphics Processing Units} (GPUs).
The evolution of the oxygen abundance radial gradient in the Milky Way Galaxy disk

Abstract We review the state of our chemical evolution models for spiral and low mass galaxies. We analyze the consequences of using different stellar yields, infall rate laws and star formation prescriptions in the time/redshift evolution of the radial distributions of abundances, and other quantities as star formation rate or gas densities, in the Milky Way Galaxy; In particular we will study the evolution of the oxygen abundance radial gradient analyzing its relation with the ratio SFR/infall. We also compare the results with our old chemical evolution models, cosmological simulations and with the existing data, mainly with the planetary nebulae abundances.
Varieties of sums of powers

The variety of sums of powers of a homogeneous polynomial of degree d in n variables is defined and investigated in some examples, old and new. These varieties are studied via apolarity and syzygies. Classical results of Sylvester (1851), Hilbert (1888), Dixon and Stuart (1906) and some more recent results of Mukai (1992) are presented together with new results for the cases (n,d)=(3,8), (4,2), (5,3). In the last case the variety of sums of 8 powers of a general cubic form is a Fano 5-fold of index 1 and degree 660.
Kondo effect in coupled quantum dots with RKKY interaction: Effects of finite temperature and magnetic field

We study transport through two quantum dots coupled by a Ruderman-Kittel-Kasuya-Yoshida interaction as a function of temperature and magnetic field. By applying the numerical renormalization group method, we obtain the transmission and the linear conductance. At zero temperature and magnetic field, we observe a quantum phase transition between the Kondo screened state and a local spin singlet as the RKKY interaction is tuned. Above the critical RKKY coupling, the Kondo peak is split. However, we find that both finite temperature and magnetic field restore the Kondo resonance. Our results agree well with recent transport experiments on gold grain quantum dots in the presence of magnetic impurities [H. B. Heersche et al., Phys. Rev. Lett. 96, 017205 (2006)].
A close look at the dwarf AGN of NGC 4395: optical and near-IR integral field spectroscopy

Intermediate mass black holes (10$^3$-10$^5$ M$_\odot$) in the center of dwarf galaxies are believed to be analogous to growing Active Galactic Nuclei (AGN) in the early Universe. Their characterization can provide insight about the early galaxies. We present optical and near-infrared integral field spectroscopy of the inner $\sim$50 pc of the dwarf galaxy NGC4395, known to harbor an AGN. NGC 4395 is an ideal candidate to investigate the nature of dwarf AGN, as it is nearby ($d\approx4.4$ Mpc) enough to allow a close look at its nucleus. The optical data were obtained with the Gemini GMOS-IFU covering the 4500 A to 7300 A spectral range at a spatial resolution of 10 pc. The J and K-band spectra were obtained with the Gemini NIFS at spatial resolutions of $\sim$5 pc. The gas kinematics show a compact, rotation disk component with a projected velocity amplitude of 25 km s$^{-1}$. We estimate a mass of $7.7\times10^5$ M$_\odot$ inside a radius of 10 pc. From the H$\alpha$ broad line component, we estimate the AGN bolometric luminosity as $L_{ bol}=(9.9\pm1.4)\times10^{40}$ erg s$^{-1}$ and a mass $M_{ BH}=(2.5^{+1.0}_{-0.8})\times10^5$ M$_\odot$ for the central black hole. The mean surface mass densities for the ionized and molecular gas are in the ranges (1-2) M$_{\odot} $pc$^{-2}$ and (1-4)$\times10^{-3}$ M${_\odot}$ pc$^{-2}$ and the average ratio between ionized and hot molecular gas masses is $\sim$500. The emission-line flux distributions reveal an elongated structure at 24 pc west of the nucleus, which is blueshifted relative to the systemic velocity of the galaxy by $\approx$30 km s$^{-1}$. We speculate that this structure is originated by the accretion of a gas-rich small satellite or by a low metallicity cosmic cloud.
Operational nonlocality.

An operational concept of locality whose quantum violation is indicated independently of any other assumption(s) seems to be lacking in the quantum foundations literature so far. Bell's theorem only shows that quantum correlations violate the conjunction of the ontological assumptions of localism and determinism. Taking a cue from computational complexity theory, here we define such a concept of locality in terms of a class of operational decision problems, and propose that Einstein-Podolsky-Rosen (EPR) steering in its basic asymmetric formulation gives a specific realization of this class. Various nonclassical (convex) operational theories, including quantum mechanics, are shown to be nonlocal according to this operational criterion. We discuss several ramifications arising from this result. It indicates a basic difference between quantum no-signaling and relativistic no-signaling, and suggests an information theoretic derivation of the former from other basic principles in the convex framework. It elucidates the connection between two different bounds on nonlocality, due to Oppenheim and Wehner (2010) and Banik et al. (2015), thereby highlighting the interplay and contrast between uncertainty and measurement incompatibility. Our result provides an argument supporting the realist interpretation of the quantum state, and helps clarify why Spekkens' toy model (2007) features steering but not Bell nonlocality.
Big Bounce and Closed Universe from Spin and Torsion

We analyze the dynamics of a homogeneous and isotropic universe in the Einstein–Cartan theory of gravity. The coupling between the spin and torsion prevents gravitational singularities and replaces the Big Bang with a nonsingular big bounce, at which the universe transitions from contraction to expansion. We show that a closed universe exists only when the product of the scale factor and temperature is higher than a particular threshold, contrary to a flat universe and an open universe, which are not restricted. During inflation, this product must increase to another threshold, so that the universe can reach dark-energy acceleration.
A non-perturbative study of 4d U(1) non-commutative gauge theory — the fate of one-loop instability

Recent perturbative studies show that in 4d non-commutative spaces, the trivial (classically stable) vacuum of gauge theories becomes unstable at the quantum level, unless one introduces sufficiently many fermionic degrees of freedom. This is due to a negative IR-singular term in the one-loop effective potential, which appears as a result of the UV/IR mixing. We study such a system non-perturbatively in the case of pure U(1) gauge theory in four dimensions, where two directions are non-commutative. Monte Carlo simulations are performed after mapping the regularized theory onto a U(N) lattice gauge theory in d = 2. At intermediate coupling strength, we find a phase in which open Wilson lines acquire non-zero vacuum expectation values, which implies the spontaneous breakdown of translational invariance. In this phase, various physical quantities obey clear scaling behaviors in the continuum limit with a fixed non-commutativity parameter θ, which provides evidence for a possible continuum theory. The extent of the dynamically generated space in the non-commutative directions becomes finite in the above limit, and its dependence on θ is evaluated explicitly. We also study the dispersion relation. In the weak coupling symmetric phase, it involves a negative IR-singular term, which is responsible for the observed phase transition. In the broken phase, it reveals the existence of the Nambu-Goldstone mode associated with the spontaneous symmetry breaking.
Face image analysis by unsupervised learning and redundancy reduction

In a task such as face recognition, much of the important information may be contained in the high-order relationships among the image pixels. Representations such as "Eigenfaces" (197) and "Holons" (48) are based on Principal component analysis (PCA), which encodes the correlational structure of the input, but does not address high-order statistical dependencies such as relationships among three or more pixels. Independent component analysis (ICA) is a generalization of PCA which encodes the high-order dependencies in the input in addition to the correlations. Representations for face recognition were developed from the independent components of face images. The ICA representations were superior to PCA for recognizing faces across sessions and changes in expression. ICA was compared to more than eight other image analysis methods on a task of recognizing facial expressions in a project to automate the Facial Action Coding System (62). These methods included estimation of optical flow; representations based on the second-order statistics of the full face images such Eigenfaces (47, 197) local feature analysis (156), and linear discriminant analysis (23); and representations based on the outputs of local filters, such as a Gabor wavelet representations (50, 113) and local PCA (153). The ICA and Gabor wavelet representations achieved the best performance of 96% for classifying 12 facial actions. Relationships between the independent component representation and the Gabor representation are discussed. Temporal redundancy contains information for learning invariances. Different views of a face tend to appear in close temporal proximity as the person changes expression, pose, or moves through the environment. The final chapter modeled the development of viewpoint invariant responses to faces from visual experience in a biological system by encoding spatio-temporal dependencies. The simulations combined temporal smoothing of activity signals with Hebbian learning (72) in a network with both feed-forward connections and a recurrent layer that was a generalization of a Hopfield attractor network. Following training on sequences of graylevel images of faces as they changed pose, multiple views of a given face fell into the same basin of attraction, and the system acquired representations of faces that were approximately viewpoint invariant.
On the continuum diagnostics of photospheric faculae.

Maps reproducing the intensity contrast in the continuum (lambda=5000 A) are obtained for a facular point at different positions on the solar disk, and the contribution function of the emergent intensity is analyzed for several representative lines of sight. A two-component, axially symmetric model is used, whose thermodynamic structure is derived from that of a magnetostatic flux tube, representative of a small filigree element.The wall of the flux tube appears to have a dominant role, with respect to the interior, in determining the observable contrast: hence the reliability of the semiempirical models obtained by inversion of continuum data is seriously questioned. The center-to-limb variation of the average contrast does not vary with the shape of the flux tube (a cylinder and a funnel are considered), the only difference being that the map at . mu. =1.9, for the funnel, shows a thin, very bright ring.The two-component approximation, neglecting the precise structure of the wall, causes an overestimate of the contrast; a discussion of this effect is given.
A unified approach to determining the early exercise boundary position at expiry for American style of general class of derivatives

In this paper, we present a new method for calculating the limit of early exercise boundary at expiry. We price American style of general derivative using a formula expressed as a sum of the value of European style of derivative and so called American premium. We use the latter expression to calculate an analytic formula for limit of early exercise boundary at expiry. Method applied on American style plain vanilla, Asian and lookback options yields identical results with already known values. Results for selected American style of derivative strategies are compared with limits calculated by the PSOR method.
Preventive impacts of vitamin C on memory damage caused by unpredictable chronic mild stress in relation to biochemical parameters in the hippocampus of male rats

ABSTRACT The present study focused on examining the impact of vitamin C (Vit C) administration on the function of memory and the status of oxidative stress (OS) in the hippocampal area of the brain using an unpredictable chronic mild stress (UCMS) model in rats. To this end, 50 male Wistar rats (11-12 weeks of age at the start of the study) were assigned to five groups of six animals, including control, UCMS, UCMS + Vit C 50 mg/Kg, UCMS + Vit C 100 mg/Kg, and UCMS + Vit C 400 mg/Kg. The animals received daily intraperitoneal injections of Vit C at a certain time (9 am) before the initiation of a stressor. UCMS, including a progression of typical stressors, was applied for four weeks. Subsequently, using the passive avoidance (PA) and Morris water maze (MWM) tests were performed to investigate learning and memory. Eventually, hippocampal tissues were evaluated in terms of OS criteria. The results revealed that the latency to enter the dark chamber (P < 0. 01 and P < 0.05, PA test) and the time spent in the target quadrant (P < 0.0001, MWM test) were shorter in the UCMS group, while latency to discover the platform was longer (P < 0.05 and P < 0.001, MWM test) compared to the control group. However, UCMS decreased the content of thiol (P < 0.0001), as well as the activities of catalase (P < 0.0001) and superoxide dismutase (P < 0.0001), whereas the concentration of malondialdehyde (P < 0.01) increased in the hippocampal region of the brain in comparison to the control group. Interestingly, Vit C treatment reversed the mentioned effects of UCMS. Therefore, the latency to enter the dark chamber (P < 0. 05 and P < 0.01,1 and 24 h after the shock, PA test, UCMS + Vit C 400) and the time spent in the target quadrant (P < 0. 01 and P < 0.05, MWM test, UCMS + Vit C 400 and UCMS + Vit C 100, respectively) were longer in the UCMS + Vit C groups. Moreover, Vit C increased the content of thiol (P < 0.05, UCMS + Vit C 400), as well as the activity of catalase (P < 0.001, UCMS + Vit C 400) and superoxide dismutase (P < 0.0001, UCMS + Vit C 400, UCMS + Vit C 100), whereas the concentration of malondialdehyde (P < 0. 05 and P < 0.01, UCMS + Vit C 100, UCMS + Vit C 400) decreased in the hippocampal region of the brain in comparison to the UCMS group. Overall, these results suggest that Vit C could reverse UCMS-induced learning and memory impairment possibly through the modulation of brain OS. Key points Memory and learning impairments were induced by unpredictable chronic mild stress (UCMS) Vitamin C could prevent cognitive impairments caused by UCMS in rats by attenuation of oxidative stress in the brain.
The Norwegian network for personality disorders – development, contributions and challenges through 30 years

Abstract Background Established in 1992, the Norwegian Network for Personality Disorders (The Network) is a clinical research collaboration of specialist mental health and addiction services in Norway. Its primary focus is to facilitate systematic and relevant clinical assessment for patients with personality disorder and evaluate progress in psychotherapeutic treatment. However, large-scale data registers for personality disorder are still unique. This article presents the circumstances that led to the establishment of the Network, and its development and challenges in many areas, and through various phases. Methods In the following, we will outline how this close interaction between researchers, clinicians, and well-adapted systems has facilitated cooperation and clinical research. We will highlight some key factors that have been decisive during the network’s development, and not least for further adaptation and existence. Results Through 30 years, the Network has succeeded in establishing a large and sustainable clinical research collaboration with a persistent focus on personality disorder and psychotherapeutic treatment. The collaboration has resulted in a broad range of scientific contributions to the understanding of personality disorder, assessment and measurement methods, treatment alliance, clinical outcomes, service utilization, and costs. In addition, The Network has also resulted in a number of synergy effects that have benefited clinicians, patients, and researchers. Conclusions The Norwegian Network for Personality Disorders has become an acknowledged institution in the field. Many aspects of its development, organization, maintenance, and solutions to challenges may be relevant to others who plan to establish, maintain, or further develop similar collaborations.
Flocking of multi‐agent dynamical systems with intermittent nonlinear velocity measurements

In this paper, the problem of flocking control in networks of multiple dynamical agents with intermittent nonlinear velocity measurements is studied. A new flocking algorithm is proposed to guarantee the states of the velocity variables of all the dynamical agents to converge to consensus while ensuring collision avoidance of the whole group, where each agent is assumed to obtain some nonlinear measurements of the relative velocity between itself and its neighbors only on a sequence of non‐overlapping time intervals. The results are then extended to the scenario of flocking with a nonlinearly dynamical virtual leader, where only a small fraction of agents are informed and each informed agent can obtain intermittent nonlinear measurements of the relative velocity between itself and the virtual leader. Theoretical analysis shows that the achieved flocking in systems with or without a virtual leader is robust against the time spans of the agent speed‐sensors. Finally, some numerical simulations are provided to illustrate the effectiveness of the new design. Copyright © 2011 John Wiley & Sons, Ltd.
Vibrational properties of sodosilicate glasses from first-principles calculations

The vibrational properties of three sodosilicate glasses have been investigated in the framework of density functional theory. The pure vibrational density of states has been calculated for all systems and the different vibrational modes have been assigned to specific atoms or structural units. It is shown that the Na content affects several vibrational features as the position and intensity of the R band or the mixing of the rocking and bending atomic motions of the Si-O-Si bridges. The calculated Raman spectra have been found to agree with experimental observations and their decomposition indicated the dominant character of the non-bridging oxygen contribution on the spectra, in particular for the high-frequency band, above 800 cm −1 . The decomposition of the high-frequency Raman feature into vibrations of the depolymerized tetrahedra (i.e. Q n -units) has revealed spectral shapes of the partial contributions that cannot be accounted for by simple Gaussians as frequently assumed in the treatment of experimentally obtained Raman spectra.
Does the self-reported playfulness of older adults influence their wellbeing? An exploratory study

Abstract Aim: Older adults represent a growing demographic in Australia who are at an increased risk of isolation, loneliness, and experiencing poorer overall health. Thus, the need for understanding factors that influence older adults’ wellbeing is important. Emergent research into adult playfulness has shown positive associations with indicators of wellbeing, but limited research has been conducted in older adults (60+). This study investigated whether types of playfulness present in Australian older adults (60+) were predictive of their wellbeing. Method: An online survey was administered (n = 123) using the Other-directed, Light-hearted, Intellectual, Whimsical (OLIW) Playfulness Scale and the PERMA-Profiler wellbeing measure to explore playfulness types and its influence on self-reported wellbeing. Multiple linear regression analysis with bootstrapping was completed to determine if any significant relationships between OLIW and PERMA-Profiler subscales existed. Results: Playfulness was a significant predictor of wellbeing. The OLIW Other-directed subscale (enjoyment of others, using playfulness in tense situations) was the greatest predictor of PERMA-Profiler subscales with OLIW Intellectual and Whimsical subscales making smaller contributions. Conclusion/implications: Playfulness was shown to be a significant contributor to wellbeing in older adults and should be used as a part of occupational therapy intervention, especially when considering social activities.
HELIOS: High-speed sequence alignment in optics

In response to the imperfections of current sequence alignment methods, originated from the inherent serialism within their corresponding electrical systems, a few optical approaches for biological data comparison have been proposed recently. However, due to their low performance, raised from their inefficient coding scheme, this paper presents a novel all-optical high-throughput method for aligning DNA, RNA, and protein sequences, named HELIOS. The HELIOS method employs highly sophisticated operations to locate character matches, single or multiple mutations, and single or multiple indels within various biological sequences. On the other hand, the HELIOS optical architecture exploits high-speed processing and operational parallelism in optics, by adopting wavelength and polarization of optical beams. For evaluation, the functionality and accuracy of the HELIOS method are approved through behavioral and optical simulation studies, while its complexity and performance are estimated through analytical computation. The accuracy evaluations indicate that the HELIOS method achieves a precise pairwise alignment of two sequences, highly similar to those of Smith-Waterman, Needleman-Wunsch, BLAST, MUSCLE, ClustalW, ClustalΩ, T-Coffee, Kalign, and MAFFT. According to our performance evaluations, the HELIOS optical architecture outperforms all alternative electrical and optical algorithms in terms of processing time and memory requirement, relying on its highly sophisticated method and optical architecture. Moreover, the employed compact coding scheme highly escalates the number of input characters, and hence, it offers reduced time and space complexities, compared to the electrical and optical alternatives. It makes the HELIOS method and optical architecture highly applicable for biomedical applications.