Miracle-dz/UniFAR-FTUs huggingface dataset:
Flaring Activity of Proxima Centauri from TESS Observations: Quasiperiodic Oscillations during Flare Decay and Inferences on the Habitability of Proxima b

We analyze the light curve of the M5.5 dwarf Proxima Centauri obtained by the Transiting Exoplanet Survey Satellite (TESS) in Sectors 11 and 12. In the ≈50 day long light curve we identified and analyzed 72 flare events. The flare rate was 1.49 events per day; in total, 7.2% of the observing time was classified as flaring. The estimated flare energies were on the order of 1030–1032 erg in the TESS passband (≈4.8× higher in bolometric energies, but on the same order of magnitude). Most of the eruptions appeared in groups. Two events showed quasiperiodic oscillations during their decay phase with a timescale of a few hours, which could be caused by quasiperiodic motions of the emitting plasma or oscillatory reconnection. From the cumulative flare frequency distribution we estimate that superflares with energy output of 1033 erg are expected to occur three times per year, while magnitude larger events (with 1034 erg) can occur every second year. This reduces the chances of habitability of Proxima Cen b, although earlier numerical models did not rule out the existence of liquid water on the planetary surface. We did not find any obvious signs of planetary transit in the light curve.
Transferability of Spectral Graph Convolutional Neural Networks

This paper focuses on spectral graph convolutional neural networks (ConvNets), where filters are defined as elementwise multiplication in the frequency domain of a graph. In machine learning settings where the dataset consists of signals defined on many different graphs, the trained ConvNet should generalize to signal on graphs unseen in the training set. It is thus important to transfer filters from one graph to the other. Transferability, which is a certain type of generalization capability, can be loosely defined as follows: if two graphs describe the same phenomenon, then a single filter/ConvNet should have similar repercussions on both graphs. This paper aims at debunking the common misconception that spectral filters are not transferable. We show that if two graphs discretize the same continuous metric space, then a spectral filter/ConvNet has approximately the same repercussion on both graphs. Our analysis is more permissive than the standard analysis. Transferability is typically described as the robustness of the filter to small graph perturbations and re-indexing of the vertices. Our analysis accounts also for large graph perturbations. We prove transferability between graphs that can have completely different dimensions and topologies, only requiring that both graphs discretize the same underlying continuous space.
Interspecific competition in tadpoles growth inhibition and growth retrieval in natterjack toads bufo calamita

(1) Common frog, Rana temporaria, tadpoles inhibit the growth, prolong the development, and reduce the survival of natterjack toad, Bufo calamita, tadpoles. In a replicated pond experiment, B. calamita tadpoles treated with the faeces of R. temporaria tadpoles displayed growth inhibition. A unicellular organism was identified in tadpole faeces which is known to cause inhibition in laboratory cultures. (2) Overlap in the development periods of R. temporaria and B. calamita tadpoles is reduced when R. temporaria metamorphose before B. calamita. This subjects natterjacks to a steadily declining level of interspecific competition. Under such conditions, B. calamita tadpoles may be released from an initial period of growth inhibition, and metamorphose the same size as controls raised without R. temporaria. However, even with growth retrieval, time to metamorphosis and mortality are both increased relative to controls. (3) The effects of large R. temporaria tadpoles on B. calamita were not significantly different from those of small R. temporaria tadpoles. Large R. temporaria tadpoles metamorphosed before small R. temporaria tadpoles, thereby providing a longer retrieval period for inhibited B. calamita tadpoles. (4) When the breeding periods of R. temporaria and B. calamita are well-separated, temporal niche overlap between the tadpole stages will be reduced and growth inhibition ameliorated. However, such conditions may still prolong B. calamita development. Tadpoles may therefore be exposed to aquatic predators for longer, and incur a greater risk of dying as a result of pond desiccation.
Nobeyama 45 m Cygnus-X CO Survey. II. Physical Properties of C18O Clumps

We report the statistical physical properties of the C18O(J = 1–0) clumps present in a prominent cluster-forming region, Cygnus X, using the data set obtained by the Nobeyama 45 m radio telescope. This survey covers 9 deg2 of the northern and southern regions of Cygnus X, and, in total, 174 C18O clumps are identified using the dendrogram method. Assuming a distance of 1.4 kpc, these clumps have radii of 0.2–1 pc, velocity dispersions of <2.2 km s−1, gas masses of 30–3000 M⊙, and H2 densities of (0.2–5.5) × 104 cm−3. We confirm that the C18O clumps in the northern region have a higher H2 density than those in the southern region, supporting the existence of a difference in the evolutionary stages, consistent with the star-formation activity of these regions. The difference in the clump properties of the star-forming and starless clumps is also confirmed by the radius, velocity dispersion, gas mass, and H2 density. The average virial ratio of 0.3 supports that these clumps are gravitationally bound. The C18O clump mass function shows two spectral index components, α = −1.4 in 55–140 M⊙ and α = −2.1 in >140 M⊙, which are consistent with the low- and intermediate-mass parts of the Kroupa’s initial mass function. The spectral index of the star-forming clumps >140 M⊙ is consistent with that of the starless clumps ranging from 55–140 M⊙, suggesting that the latter will evolve into star-forming clumps while retaining the gas accretion. Assuming a typical star-formation efficiency of molecular clumps (10%), about 10 C18O clumps having a gas mass of >103 M⊙ will evolve into open clusters containing one or more OB stars.
Propensity Score Analysis With Latent Covariates: Measurement Error Bias Correction Using the Covariate’s Posterior Mean, aka the Inclusive Factor Score

We address measurement error bias in propensity score (PS) analysis due to covariates that are latent variables. In the setting where latent covariate X is measured via multiple error-prone items W , PS analysis using several proxies for X—the W items themselves, a summary score (mean/sum of the items), or the conventional factor score (i.e., predicted value of X based on the measurement model)—often results in biased estimation of the causal effect because balancing the proxy (between exposure conditions) does not balance X. We propose an improved proxy: the conditional mean of X given the combination of W , the observed covariates Z, and exposure A, denoted X WZA . The theoretical support is that balancing X WZA (e.g., via weighting or matching) implies balancing the mean of X. For a latent X, we estimate X WZA by the inclusive factor score (iFS)—predicted value of X from a structural equation model that captures the joint distribution of ( X , W , A ) given Z. Simulation shows that PS analysis using the iFS substantially improves balance on the first five moments of X and reduces bias in the estimated causal effect. Hence, within the proxy variables approach, we recommend this proxy over existing ones. We connect this proxy method to known results about valid weighting/matching functions. We illustrate the method in handling latent covariates when estimating the effect of out-of-school suspension on risk of later police arrests using National Longitudinal Study of Adolescent to Adult Health data.
Exponential slowdown for larger populations: the (µ + 1)-EA on monotone functions

Pseudo-Boolean monotone functions are unimodal functions which are trivial to optimize for some hillclimbers, but are challenging for a surprising number of evolutionary algorithms. A general trend is that evolutionary algorithms are efficient if parameters like the mutation rate are set conservatively, but may need exponential time otherwise. In particular, it was known that the (1 + 1)-EA and the (1 + λ)-EA can optimize every monotone function in pseudolinear time if the mutation rate is c/n for some c < 1, but that they need exponential time for some monotone functions for c > 2.2. The second part of the statement was also known for the (µ + 1)-EA. In this paper we show that the first statement does not apply to the (µ + 1)-EA. More precisely, we prove that for every constant c > 0 there is a constant µ0 ∈ N such that the (µ + 1)-EA with mutation rate c/n and population size µ0 ≤ µ ≤ n needs superpolynomial time to optimize some monotone functions. Thus, increasing the population size by just a constant has devastating effects on the performance. This is in stark contrast to many other benchmark functions on which increasing the population size either increases the performance significantly, or affects performance only mildly. The reason why larger populations are harmful lies in the fact that larger populations may temporarily decrease selective pressure on parts of the population. This allows unfavorable mutations to accumulate in single individuals and their descendants. If the population moves sufficiently fast through the search space, then such unfavorable descendants can become ancestors of future generations, and the bad mutations are preserved. Remarkably, this effect only occurs if the population renews itself sufficiently fast, which can only happen far away from the optimum. This is counter-intuitive since usually optimization becomes harder as we approach the optimum. Previous work missed the effect because it focused on monotone functions that are only deceptively close to the optimum.
The knot Floer cube of resolutions and the composition product

We examine the relationship between the oriented cube of resolutions for knot Floer homology and HOMFLY-PT homology. By using a filtration induced by additional basepoints on the Heegaard diagram for a knot [Formula: see text], we see that the filtered complex decomposes as a direct sum of HOMFLY-PT complexes of various subdiagrams. Applying Jaeger’s composition product formula for knot polynomials, we deduce that the graded Euler characteristic of this direct sum is the HOMFLY-PT polynomial of [Formula: see text].
Alignment between satellite and central galaxies in the EAGLE simulation: dependence on the large-scale environments

The alignment between satellite and central galaxies serves as a proxy for addressing the issue of galaxy formation and evolution, and has been investigated abundantly in observations and theoretical works. Most scenarios indicate that the satellites preferentially are located along the major axis of their central galaxy. Recent work shows that the strength of alignment signals depends on the large-scale environment in observations. We use the publicly-released data from EAGLE to figure out whether the same effect can be found in the associated hydrodynamic simulation. We found much stronger environmental dependency of alignment signals in the simulation. We also explore change of alignments to address the formation of this effect.
Cross-Platform Question Answering in Social Networking Services

Title of dissertation: CROSS-PLATFORM QUESTION ANSWERING IN SOCIAL NETWORKING SERVICES Mossaab Bagdouri, Doctor of Philosophy, 2017 Dissertation directed by: Professor Douglas W. Oard College of Information Studies and Department of Computer Science The last two decades have made the Internet a major source for knowledge seeking. Several platforms have been developed to find answers to one’s questions such as search engines and online encyclopedias. The wide adoption of social networking services has pushed the possibilities even further by giving people the opportunity to stimulate the generation of answers that are not already present on the Internet. Some of these social media services are primarily community question answering (CQA) sites, while the others have a more general audience but can also be used to ask and answer questions. The choice of a particular platform (e.g., a CQA site, a microblogging service, or a search engine) by some user depends on several factors such as awareness of available resources and expectations from different platforms, and thus will sometimes be suboptimal. Hence, we introduce cross-platform question answering, a framework that aims to improve our ability to satisfy complex information needs by returning answers from different platforms, including those where the question has not been originally asked. We propose to build this core capability by defining a general architecture for designing and implementing real-time services for answering naturally occurring questions. This architecture consists of four key components: (1) real-time detection of questions, (2) a set of platforms from which answers can be returned, (3) question processing by the selected answering systems, which optionally involves question transformation when questions are answered by services that enforce differing conventions from the original source, and (4) answer presentation, including ranking, merging, and deciding whether to return the answer. We demonstrate the feasibility of this general architecture by instantiating a restricted development version in which we collect the questions from one CQA website, one microblogging service or directly from the asker, and find answers from among some subset of those CQA and microblogging services. To enable the integration of new answering platforms in our architecture, we introduce a framework for automatic evaluation of their effectiveness. CROSS-PLATFORM QUESTION ANSWERING IN SOCIAL NETWORKING SERVICES
Watch It Twice: Video Captioning with a Refocused Video Encoder

With the rapid growth of video data and the increasing demands of various crossmodal applications such as intelligent video search and assistance towards visually-impaired people, video captioning task has received a lot of attention recently in computer vision and natural language processing fields. The state-of-the-art video captioning methods focus more on encoding the temporal information, while lacking effective ways to remove irrelevant temporal information and also neglecting the spatial details. In particular, the current unidirectional video encoder can be negatively affected by irrelevant temporal information, especially the irrelevant information at the beginning and at the end of a video. In addition, disregarding detailed spatial features may lead to incorrect word choices in decoding. In this paper, we propose a novel recurrent video encoding method and a novel visual spatial feature for the video captioning task. The recurrent encoding module encodes the video twice with a predicted key frame to avoid irrelevant temporal information often occurring at the beginning and at the end of a video. The novel spatial features represent spatial information from different regions of a video and provide the decoder with more detailed information. Experiments on two benchmark datasets show superior performance of the proposed method.
The Next Generation Fornax Survey (NGFS). VI. The Alignment of Dwarf Galaxies in the Fornax Cluster

Using the photometric data from the Next Generation Fornax Survey, we find a significant radial alignment signal among the Fornax dwarf galaxies. For the first time, we report that the radial alignment signal of nucleated dwarfs is stronger than that of non-nucleated ones at the 2. 4σ confidence level, and the dwarfs located in the outer region (R > Rvir/3; Rvir is the Fornax virial radius) show a slightly stronger radial alignment signal than those in the inner region (R < Rvir/3) at the 1. 5σ level. We also find that the significance of the radial alignment signal is independent of the luminosities or sizes of the dwarfs.
Making Sense of Vision and Touch: Learning Multimodal Representations for Contact-Rich Tasks

Contact-rich manipulation tasks in unstructured environments often require both haptic and visual feedback. It is nontrivial to manually design a robot controller that combines these modalities, which have very different characteristics. While deep reinforcement learning has shown success in learning control policies for high-dimensional inputs, these algorithms are generally intractable to train directly on real robots due to sample complexity. In this article, we use self-supervision to learn a compact and multimodal representation of our sensory inputs, which can then be used to improve the sample efficiency of our policy learning. Evaluating our method on a peg insertion task, we show that it generalizes over varying geometries, configurations, and clearances, while being robust to external perturbations. We also systematically study different self-supervised learning objectives and representation learning architectures. Results are presented in simulation and on a physical robot.
Generalized Phenomenological Models of Dark Energy

It was first observed at the end of the last century that the universe is presently accelerating. Ever since, there have been several attempts to explain this observation theoretically. There are two possible approaches. The more conventional one is to modify the matter part of the Einstein field equations, and the second one is to modify the geometry part. We shall consider two phenomenological models based on the former, more conventional approach within the context of general relativity. The phenomenological models in this paper consider a Λ term firstly a function of a¨/a and secondly a function of ρ, where a and ρ are the scale factor and matter energy density, respectively. Constraining the free parameters of the models with the latest observational data gives satisfactory values of parameters as considered by us initially. Without any field theoretic interpretation, we explain the recent observations with a dynamical cosmological constant.
Runtime QoS service for application-driven adaptation in network computing

A distributed application executing on a Network of Workstations (NOW) needs to be resource state aware to possibly adapt itself accordingly in order to keep satisfying the desired Quality of Service (QoS) demands throughout its lifespan. We implemented a QoS service to enable application-driven adaptation for performance and fault tolerance at runtime. The service is associated with lightweight middleware that monitors the state and load of all application entities (e.g., machines, tasks, and logical network links). Moreover, it makes its services available to an application task via an anonymous and simple to use QoS API. We present a Manager-Worker application that uses our fault tolerance QoS API to adapt for Worker faults in order to avoid application deadlock at runtime. Moreover, we show how a dynamic application-level scheduler can easily utilize the QoS API to find efficient schedules. Furthermore, we quantified the overhead of the QoS middleware in various scenarios to demonstrate that it has minor impact on the performance of the application it is servicing.
Tilt stability and the degree of irrationality of surfaces on threefolds

Let $S$ be a smooth projective surface on a smooth threefold $X$ such that $X$ has Picard rank 1 and NS$(S)$ is generated by the restriction of divisors from X. We show that if $X$ satisfies the Bogomolov-Gieseker type inequality for tilt semistable objects conjectured by Bayer-Macr\`i-Stellari, then the minimum degree of a dominant rational map $S\dashrightarrow\mathbb{P}^2$ is either relatively large or determined by a net of curves of low degree on $S$. As one application, we prove that the complete intersection of three very general quadrics in $\mathbb{P}^5$ has degree of irrationality 4.
J-PLUS: photometric calibration of large-area multi-filter surveys with stellar and white dwarf loci

Aims. We present the photometric calibration of the 12 optical passbands observed by the Javalambre Photometric Local Universe Survey (J-PLUS). Methods. The proposed calibration method has four steps: (i) definition of a high-quality set of calibration stars using Gaia information and available 3D dust maps; (ii) anchoring of the J-PLUS gri passbands to the Pan-STARRS photometric solution, accounting for the variation in the calibration with the position of the sources on the CCD; (iii) homogenization of the photometry in the other nine J-PLUS filters using the dust de-reddened instrumental stellar locus in (𝒳 − r) versus (g − i) colours, where 𝒳 is the filter to calibrate. The zero point variation along the CCD in these filters was estimated with the distance to the stellar locus. Finally, (iv) the absolute colour calibration was obtained with the white dwarf locus. We performed a joint Bayesian modelling of 11 J-PLUS colour–colour diagrams using the theoretical white dwarf locus as reference. This provides the needed offsets to transform instrumental magnitudes to calibrated magnitudes outside the atmosphere. Results. The uncertainty of the J-PLUS photometric calibration, estimated from duplicated objects observed in adjacent pointings and accounting for the absolute colour and flux calibration errors, are ∼19 mmag in u, J0378, and J0395; ∼11 mmag in J0410 and J0430; and ∼8 mmag in g, J0515, r, J0660, i, J0861, and z. Conclusions. We present an optimized calibration method for the large-area multi-filter J-PLUS project, reaching 1–2% accuracy within an area of 1022 square degrees without the need for long observing calibration campaigns or constant atmospheric monitoring. The proposed method will be adapted for the photometric calibration of J-PAS, that will observe several thousand square degrees with 56 narrow optical filters.
Primordial power spectra of cosmological fluctuations with generalized uncertainty principle and maximum length quantum mechanics

The existence of the cosmological particle horizon as the maximum measurable length $l_{max}$ in the universe leads to a generalization of the quantum uncertainty principle (GUP) to the form $\Delta x \Delta p \geq \frac{\hbar}{2}\frac{1}{1-\alpha\Delta x^2} $, where $\alpha\equiv l_{max}^{-2}$. The effects of this GUP on simple quantum mechanical systems has been shown recently by one of the authors\cite{Perivolaropoulos:2017rgq} to be extremely small (beyond current measurements) due to the extremely large scale of the current particle horizon. This is not the case in the Early Universe during the quantum generation of the inflationary primordial fluctuation spectrum. We estimate the effects of such GUP on the primordial fluctuation spectrum and on the corresponding spectral index. We generalize the field commutation (GFC) relation to $[\varphi(k),\pi_{\varphi}(k')]$=$i\delta(k-k')\frac{1}{1-\mu\varphi^2(k)}$, where $\mu\sim \alpha^2\equiv l_{max}^{-4}$ is a GFC parameter, $\varphi$ denotes a scalar field and $\pi_{\varphi}$ denotes its canonical conjugate momentum. We obtain the predicted primordial perturbation spectrum as $P_S(k)=P_S^{(0)}(k)\left(1+\frac{\bar{\mu}}{k}\right)$ where $\bar{\mu}\equiv\mu V_* \simeq \sqrt{\alpha}= l_{max}^{-1}$ (here $V_*\simeq l_{max}^3$ is the volume corresponding to $l_{max}$) and $P_S^{(0)}(k)$ is the standard primordial spectrum obtained in the context of the Heisenberg uncertainty principle ($\mu=0$). We show that the predicted scalar spectral index is $n_s=1-\lambda-\frac{\bar{\mu}}{k}$ where $\lambda$ is a slow-roll parameter. Using observational constraints on the scale dependence of the spectral index $n_s$ we show that the $2\sigma$ range of $\alpha$ corresponds to $l_{max}\gtrsim 10^{26} m $ which is of the same order as the current particle horizon.