Miracle-dz/UniFAR-FTUs huggingface dataset:
Model-Based Multi-Agent RL in Zero-Sum Markov Games with Near-Optimal Sample Complexity

Model-based reinforcement learning (RL), which finds an optimal policy using an empirical model, has long been recognized as one of the corner stones of RL. It is especially suitable for multi-agent RL (MARL), as it naturally decouples the learning and the planning phases, and avoids the non-stationarity problem when all agents are improving their policies simultaneously using samples. Though intuitive, easy-to-implement, and widely-used, the sample complexity of model-based MARL algorithms has not been fully investigated. In this paper, our goal is to address the fundamental question about its sample complexity. We study arguably the most basic MARL setting: two-player discounted zero-sum Markov games, given only access to a generative model. We show that model-based MARL achieves a sample complexity of $\tilde O(|S||A||B|(1-\gamma)^{-3}\epsilon^{-2})$ for finding the Nash equilibrium (NE) value up to some $\epsilon$ error, and the $\epsilon$-NE policies with a smooth planning oracle, where $\gamma$ is the discount factor, and $S,A,B$ denote the state space, and the action spaces for the two agents. We further show that such a sample bound is minimax-optimal (up to logarithmic factors) if the algorithm is reward-agnostic, where the algorithm queries state transition samples without reward knowledge, by establishing a matching lower bound. This is in contrast to the usual reward-aware setting, with a $\tilde\Omega(|S|(|A|+|B|)(1-\gamma)^{-3}\epsilon^{-2})$ lower bound, where this model-based approach is near-optimal with only a gap on the $|A|,|B|$ dependence. Our results not only demonstrate the sample-efficiency of this basic model-based approach in MARL, but also elaborate on the fundamental tradeoff between its power (easily handling the more challenging reward-agnostic case) and limitation (less adaptive and suboptimal in $|A|,|B|$), particularly arises in the multi-agent context.
Combating disinformation in a social media age

The creation, dissemination, and consumption of disinformation and fabricated content on social media is a growing concern, especially with the ease of access to such sources, and the lack of awareness of the existence of such false information. In this article, we present an overview of the techniques explored to date for the combating of disinformation with various forms. We introduce different forms of disinformation, discuss factors related to the spread of disinformation, elaborate on the inherent challenges in detecting disinformation, and show some approaches to mitigating disinformation via education, research, and collaboration. Looking ahead, we present some promising future research directions on disinformation.
X-ray spectroscopy of the γ-ray brightest nova V906 Car (ASASSN-18fv)

Shocks in gamma-ray emitting classical novae are expected to produce bright thermal and non-thermal X-rays. We test this prediction with simultaneous NuSTAR and Fermi/LAT observations of nova V906 Car, which exhibited the brightest GeV gamma-ray emission to date. The nova is detected in hard X-rays while it is still gamma-ray bright, but contrary to simple theoretical expectations, the detected 3.5-78 keV emission of V906 Car is much weaker than the simultaneously observed >100 MeV emission. No non-thermal X-ray emission is detected, and our deep limits imply that the gamma-rays are likely hadronic. After correcting for substantial absorption (N_H ~ 2 x 10^23 cm^-2), the thermal X-ray luminosity (from a 9 keV optically-thin plasma) is just ~2% of the gamma-ray luminosity. We consider possible explanations for the low thermal X-ray luminosity, including the X-rays being suppressed by corrugated, radiative shock fronts or the X-rays from the gamma-ray producing shock are hidden behind an even larger absorbing column (N_H >10^25 cm^-2). Adding XMM-Newton and Swift/XRT observations to our analysis, we find that the evolution of the intrinsic X-ray absorption requires the nova shell to be expelled 24 days after the outburst onset. The X-ray spectra show that the ejecta are enhanced in nitrogen and oxygen, and the nova occurred on the surface of a CO-type white dwarf. We see no indication of a distinct super-soft phase in the X-ray lightcurve, which, after considering the absorption effects, may point to a low mass of the white dwarf hosting the nova.
Herbicide-resistant Echinochloa oryzoides and E. phyllopogon in California Oryza sativa fields

Abstract Echinochloa oryzoides and E. phyllopogon have become the most serious weeds in California Oryza sativa since continuous flooding was used to suppress E. crus-galli. Continuous use of a limited number of available graminicides and an increasing number of control failures led to the investigation of herbicide resistance in E. oryzoides and E. phyllopogon. Greenhouse dose-response studies with postemergence (POST) applications of molinate, thiobencarb, fenoxaprop-ethyl, and bispyribac-sodium estimating GR50 (herbicide dose to inhibit growth by 50%) values suggested resistance to all herbicides in two E. phyllopogon accessions and to molinate and thiobencarb in one E. oryzoides accession when compared with susceptible E. phyllopogon and E. oryzoides controls, respectively. No resistance was detected in dose-response studies with propanil. Minimum and maximum ratios (R/S) of the GR50 values of resistant to susceptible E. phyllopogon plants (in two experiments involving two resistant accessions) were 7.8 and >13.3 for thiobencarb, 2.2 and 4.3 for molinate, 16.5 and 428.7 for fenoxaprop-ethyl, and 2.0 and 12.0 for bispyribac-sodium. Minimum and maximum E. oryzoides R/S ratios (average of two experiments) were 21.9 and 4.6 for thiobencarb and molinate, respectively. A resistant E. phyllopogon (one accession tested) and the susceptible control were killed by POST applications of glyphosate, glufosinate, and clomazone, and by a preemergence application of pendimethalin. Thus, the repeated use of the few available grass herbicides in the predominantly monocultured O. sativa of California has selected for herbicide resistance in E. oryzoides and E. phyllopogon. The introduction of herbicides with new mechanisms of action will be useful to manage herbicide-resistant E. oryzoides and E. phyllopogon. However, cross- and multiple resistance emphasize the need to integrate herbicide use with nonchemical means of weed management. Nomenclature: Bispyribac-sodium, sodium 2,6-bis[(4,6-dimethoxypyrimidin-2-yl)oxy]benzoate; clomazone; fenoxaprop-ethyl; glyphosate; glufosinate; molinate; pendimethalin; propanil; thiobencarb; Echinochloa oryzoides (Ard.) Fritsch ECHOR, early watergrass; Echinochloa phyllopogon (Stapf) Koss ECHPH, late watergrass; Echinochloa crus-galli (L.) Beauv. var. crus-galli ECHCG, barnyardgrass; Oryza sativa L. , rice.
Acis ionica (Amaryllidaceae), a new species from the Ionian area (W Greece, S Albania)

Abstract Bareka, P., Kamari, G. & Phitos, D. : Acis ionica (Amaryllidaceae), a new species from the Ionian area (W Greece, S Albania). — Willdenowia 36 (Special Issue): 357–366. — ISSN 0511-9618; © 2006 BGBM Berlin-Dahlem. doi:10.3372/wi.36. 36131 (available via http://dx.doi.org/) A new species of the recently established genus Acis, A. ionica, is described from the Ionian Islands and W Sterea Ellas in Greece and a restricted area of Albania, close to the city of Vlore. The morphological differences from its relatives are discussed and phytogeographical and karyological aspects of the group outlined. The chromosome number of the new species, 2n = 16, and its karyotype are shared with its closest relative, A. valentina from the Iberian Peninsula.
Focus-and-Expand: Training Guidance Through Gradual Manipulation of Input Features

We present a simple and intuitive Focus-and-eXpand (\fax) method to guide the training process of a neural network towards a specific solution. Optimizing a neural network is a highly non-convex problem. Typically, the space of solutions is large, with numerous possible local minima, where reaching a specific minimum depends on many factors. In many cases, however, a solution which considers specific aspects, or features, of the input is desired. For example, in the presence of bias, a solution that disregards the biased feature is a more robust and accurate one. Drawing inspiration from Parameter Continuation methods, we propose steering the training process to consider specific features in the input more than others, through gradual shifts in the input domain. \fax extracts a subset of features from each input data-point, and exposes the learner to these features first, Focusing the solution on them. Then, by using a blending/mixing parameter $\alpha$ it gradually eXpands the learning process to include all features of the input. This process encourages the consideration of the desired features more than others. Though not restricted to this field, we quantitatively evaluate the effectiveness of our approach on various Computer Vision tasks, and achieve state-of-the-art bias removal, improvements to an established augmentation method, and two examples of improvements to image classification tasks. Through these few examples we demonstrate the impact this approach potentially carries for a wide variety of problems, which stand to gain from understanding the solution landscape.
AdapterHub: A Framework for Adapting Transformers

The current modus operandi in NLP involves downloading and fine-tuning pre-trained models consisting of millions or billions of parameters. Storing and sharing such large trained models is expensive, slow, and time-consuming, which impedes progress towards more general and versatile NLP methods that learn from and for many tasks. Adapters—small learnt bottleneck layers inserted within each layer of a pre-trained model— ameliorate this issue by avoiding full fine-tuning of the entire model. However, sharing and integrating adapter layers is not straightforward. We propose AdapterHub, a framework that allows dynamic “stiching-in” of pre-trained adapters for different tasks and languages. The framework, built on top of the popular HuggingFace Transformers library, enables extremely easy and quick adaptations of state-of-the-art pre-trained models (e.g., BERT, RoBERTa, XLM-R) across tasks and languages. Downloading, sharing, and training adapters is as seamless as possible using minimal changes to the training scripts and a specialized infrastructure. Our framework enables scalable and easy access to sharing of task-specific models, particularly in low-resource scenarios. AdapterHub includes all recent adapter architectures and can be found at AdapterHub.ml
The Eurasian red squirrel

This book is an excellent and complete monograph of the biology and ecology of the Eurasian red squirrelSciurus vulgaris, in which the authors have consulted and reported nearly all the existing scientific literature to date. However, the book is more than that. Being a key conservation species on theBritish Isles and in Italy, this bookalso illustrates how the introduction of the alien Eastern grey squirrel Sciurus carolinensis and/or other exotic tree squirrel species are threatening the long-term survival of our native squirrel species.Hence, the link is quicklymadewith theworld-wide trade inanimals andhow the introduction and establishment of alien species is the second-most important cause of loss of biodiversity on our planet. Therefore the book is not only a must for people working on or interested in red squirrels, but also for wildlife managers and animal welfare activists who can learn important lessons from the competitive replacement of red by grey squirrels in particular, and gain more knowledge about the mechanisms behind threats posed by alien species for species and habitat conservation. The book startswith a short chapter on taxonomyand the evolutionary history of tree squirrels. In the second chapter on distribution, the issue of introductions is addressed, underlining that alien tree squirrels are very successful invaders and that the pet trade plays an important yet negative role, with captive animals being released or escaping and forming new populations. Chapter 3, on body form and function, produces an excellent description of the (functional) morphology of all parts of the body, linking body structure and shape to the arboreal way of life of the squirrel. The paragraph on sensory organs is very interesting, particularly the section about vibrissae (i.e. tactile hairs). Here the authors use publications often not consulted by behavioural ecologists to describe and explain how red squirrels ’feel’ their immediate surroundings, including the food they are manipulating. This chapter also touches on energetics, an important aspect to explain and/or study activity and behavioural patterns, food choice and habitat use. The paragraph on genetics gives a thorough overview of current knowledge and illustrates its importance for squirrel management and conservation. In Reproduction and development (Chapter 4), the fascinating mating system and behaviours involved in it are described in detail. The extrinsic factors (e.g. food resources) and intrinsic phenotypic parameters (e.g. female age and body mass) that affect variation in both male and female reproductive success are discussed. This chapter neatly illustrates how strongly space use, social organisation and reproductive success are interconnected. In the chapter (5) onbehaviour, descriptionsof themajor typesofbehaviour are linked with their ecological context.This chapter is complete, althoughparts ondietary choices, optimal foraging and caching behaviour have some lacunes. I had expected to findhere a
Long-tail learning via logit adjustment

Real-world classification problems typically exhibit an imbalanced or long-tailed label distribution, wherein many labels are associated with only a few samples. This poses a challenge for generalisation on such labels, and also makes naive learning biased towards dominant labels. In this paper, we present two simple modifications of standard softmax cross-entropy training to cope with these challenges. Our techniques revisit the classic idea of logit adjustment based on the label frequencies, either applied post-hoc to a trained model, or enforced in the loss during training. Such adjustment encourages a large relative margin between logits of rare versus dominant labels. These techniques unify and generalise several recent proposals in the literature, while possessing firmer statistical grounding and empirical performance.
Dispersion Analysis of Periodic Structures in Anisotropic Media: Application to Liquid Crystals

This paper presents an efficient method to compute the dispersion diagram of periodic and uniform structures with generic anisotropic media. The method takes advantage of the ability of full-wave commercial simulators to deal with finite structures having anisotropic media. In particular, the proposed method ¡extends the possibilities of commercial eigenmode solvers in the following ways:¡ (i) anisotropic materials with non-diagonal permittivity and permeability tensors can be analyzed; (ii) the attenuation constant can easily be computed in both propagating and stopband regions and lossy materials can be included in the simulation; and (iii) unbounded and radiating structures such as leaky-wave antennas can be treated. The latter feature may be considered the most remarkable, since the structures must be forcefully bounded with electric/magnetic walls in the eigensolvers of most commercial simulators. In this work, the proposed method is particularized for the study of liquid crystals (LCs) in microwave and antenna devices. Thus, the dispersion properties of a great variety of LC-based configurations are analyzed, from canonical structures, such as waveguide and microstrip, to complex reconfigurable phase shifters in ridge gap-waveguide technology and leaky-wave antennas. Our results have been validated with previously reported works in the literature and with commercial software CST and HFSS.
Effects of Different Levels of Lysine on Small Intestinal Villous Morphology in Starter Diet of Broiler Chickens

5 Abstract: The purpose of this study to demonstrate the effects of lysine supplement on small intestinal morphology of broilers chickens. In starter period control group received diet containing 1.2% lysine, Treatment 1(T1) and Treatment 2(T2) groups received diet containing 1.3% and 1.4% lysine, respectively. Intestine villous morphology examination was done by analyzing of villi's height, width, depth of crypts and the type of villous. The finding shown that as diet lysine increased, the villous height had a significant increase compared to the control group. In the starter period, the growth of intestine villous width which depends on lysine density had significant increase (P<0.05) compared to control group. As T group lysine increased (P<0.05) compared to 2 control Group, Libercuhn crypt depth had a significant increase (P<0.05). A lot of intestine villous were in a kind of leaf and tongue and also a little percent were bridge villi, Finger, Ridge and convoluted villi. In duodenum, different levels of lysine on the tongue and leaf villi had not significant effect. In the starter period, lysine increase in T and T lead to significant decrease (P<0.05) of leaf villous compared to control but has caused 12 to significant increase (P<0.05) of tongue villous in jejunum and ileum.
Precise mass measurements for the double neutron star system J1829+2456

PSR J1829+2456 is a radio pulsar in a relativistic binary system with another neutron star. It has a rotational period of 41 ms and a mildly eccentric ($e = 0.14$) 28-hr orbit. We have continued its observations with the Arecibo radio telescope and have now measured the individual neutron star masses of this system. We find the pulsar and companion masses to be $1.295\,\pm\,0.011\,M_{\odot}$ and $1.310\,\pm\,0.011\,M_{\odot}$ (uncertainties are 95% confidence, unless stated otherwise), respectively. We have also measured the proper motion for this system and used it to estimate its space velocity to be 46$^{+72}_{-30}$ km s$^{-1}$ with respect to the local standard of rest. Compared with the DNS population of measured masses, the relatively low values for companion mass, space velocity and orbital eccentricity in this system imply a similar binary evolution to that of other close double neutron star systems in which the (second-formed) companion is theorised to have been formed out of a low-kick, low mass-loss, symmetric supernova.
TACTICS OF HETEROTHERMY IN EASTERN GRAY SQUIRRELS (SCIURUS CAROLINENSIS)

Abstract To investigate seasonal tactics of energy management, core body temperature (Tb) was monitored over 1 year in eastern gray squirrels (Sciurus carolinensis) maintained on a constant diet in an outdoor enclosure. Each fortnight, we recorded hourly temperatures via radio-telemetry on 2 separate days. We also measured Tb during 10-day periods of food deprivation in winter and summer. In comparison with summer and autumn values, Tb was 1–4°C lower at all times of the daily cycle throughout winter and spring. Night and morning Tb was reduced during food deprivation, and reductions during the winter deprivation (1–3°C) generally exceeded reductions during the summer deprivation (0–2°C). Maximum sustained Tb and activity levels occurred during late afternoon or early evening hours year-round, however, and Tb at this time of day during deprivations was indistinguishable from Tb under ad-lib feeding conditions in the same season. Seasonal change in Tb, including reduction in response to food deprivation, contributes to metabolic strategies employed by eastern gray squirrels, which resemble those of other tree squirrels. Further research on mechanisms of temperature adjustment, including photoperiodism, hormones, and shifting dietary preferences, would help to illuminate the evolution of metabolic strategies among Sciuridae and other mammals.
Nature of the DLA towards Q 0528−250: High pressure and strong UV field revealed by excitation of C i, H2, and Si ii

We present the detection of excited fine-structure energy levels of singly-ionized silicon and neutral carbon associated with the proximate damped Lyman-$\alpha$ system at $z_{\rm abs}=2.811$ towards \qso. This absorber has an apparent relative velocity that is inconsistent with the Hubble flow indicating motion along the line-of-sight towards the quasar, i.e., $z_{\rm abs}>z_{\rm em}$. We measure the metallicity of the system to be ${\rm [Zn/H]}=-0.68\pm 0.02$. Using the relative populations of the fine-structure levels of SiII and CI, as well as the populations of H$_2$ rotational levels, we constrain the physical conditions of the gas. We derive hydrogen number densities of $n_{\rm H}=190^{+70}_{-50}$ cm$^{-3}$ and $260^{+30}_{-20}$ cm$^{-3}$ in two velocity components where both CI and H$_2$ are detected. Taking into account the kinetic temperature in each component, $\sim 150$K, we infer high values of thermal pressure in the cold neutral medium probed by the observations. The strengths of the UV field in Draine's unit are $I_{\rm UV} = 10^{+5}_{-3}$ and $14^{+3}_{-3}$ in each of these two components, respectively. Such enhanced UV fluxes and thermal pressure compared to intervening DLAs are likely due to the proximity of the quasar. The typical size of the absorber is $\sim 10^4$ a.u. Assuming the UV flux is dominated by the quasar, we constrain the distance between the quasar and the absorber to be $\sim 150-200$ kpc. This favours a scenario where the absorption occurs in a companion galaxy located in the group where the quasar-host galaxy resides. This is in line with studies in emission that revealed the presence of several galaxies around the quasar.
A low-luminosity core-collapse supernova very similar to SN 2005cs

We present observations and analysis of PSN J17292918+7542390, a low-luminosity Type II-P supernova (LL SN IIP). The observed sample of such events is still low, and their nature is still under debate. Such SNe are similar to SN 2005cs, a well-observed LL Type II-P event, having low expansion velocities, and small ejected 56Ni mass. We have developed a robust and relatively fast Monte Carlo code that fits semi-analytic models to light curves of core-collapse SNe. This allows the estimation of the most important physical parameters, like the radius of the progenitor star, the mass of the ejected envelope, the mass of the radioactive nickel synthesized during the explosion, among others. PSN J17292918+7542390 has $R_0 = 91_{-70}^{+119} \times 10^{11} \, \text{cm}$, $M_\text{ej} = 9. 89_{-1.00}^{+2.10} \, \mathrm{ M}_{\odot }$, $E_{\mbox{kin}} = 0. 65_{-0.18}^{+0.19} \, \text{foe}$, and $v_{\mbox{exp}} = 3332_{-347}^{+216}$ km s−1, for its progenitor radius, ejecta mass, kinetic energy, and expansion velocity, respectively. The initial nickel mass of the PSN J17292918+7542390 turned out to be $1. 55_{-0.70}^{+0.75} \times 10^{-3} \, \mathrm{M}_{\odot }$. The measured photospheric velocity at the earliest observed phase is 7000 km s−1. As far as we can tell based on the small population of observed LL SNe IIP, the determined values are typical for these events.
Identifying Reward Functions using Anchor Actions

We propose a reward function estimation framework for inverse reinforcement learning with deep energy-based policies. We name our method PQR, as it sequentially estimates the Policy, the $Q$-function, and the Reward function. PQR does not assume that the reward solely depends on the state, instead it allows for a dependency on the choice of action. Moreover, PQR allows for stochastic state transitions. To accomplish this, we assume the existence of one anchor action whose reward is known, typically the action of doing nothing, yielding no reward. We present both estimators and algorithms for the PQR method. When the environment transition is known, we prove that the PQR reward estimator uniquely recovers the true reward. With unknown transitions, we bound the estimation error of PQR. Finally, the performance of PQR is demonstrated by synthetic and real-world datasets.