Miracle-dz/UniFAR-FTUs huggingface dataset:
Seed banks and seedling occurrence in a high Arctic oasis at Alexandra Fjord, Ellesmere Island, Canada

The sizes and floras of the seed banks and seedling communities are described for a variety of habitats in a high Arctic lowland oasis on Ellesmere Island, located at 79° N latitude. Four disturbed habitats had larger seed banks than did four undisturbed habitats (averaging 3070/m2 vs. 63/m2). The seedling densities measured in the disturbed habitats were also larger (1780/m2 vs. 180/m2). The data indicate that sexual reproduction is important to the herbaceous, short-lived, ruderal species which colonize disturbed sites in the high Arctic. This contrasts with the more conservative strategy of stress-tolerant species that occur in relatively closed and undisturbed habitats, which tend to propagate by vegetative mechanisms.
Anatomy of Catastrophic Forgetting: Hidden Representations and Task Semantics

A central challenge in developing versatile machine learning systems is catastrophic forgetting: a model trained on tasks in sequence will suffer significant performance drops on earlier tasks. Despite the ubiquity of catastrophic forgetting, there is limited understanding of the underlying process and its causes. In this paper, we address this important knowledge gap, investigating how forgetting affects representations in neural network models. Through representational analysis techniques, we find that deeper layers are disproportionately the source of forgetting. Supporting this, a study of methods to mitigate forgetting illustrates that they act to stabilize deeper layers. These insights enable the development of an analytic argument and empirical picture relating the degree of forgetting to representational similarity between tasks. Consistent with this picture, we observe maximal forgetting occurs for task sequences with intermediate similarity. We perform empirical studies on the standard split CIFAR-10 setup and also introduce a novel CIFAR-100 based task approximating realistic input distribution shift.
Diabatic description of charmoniumlike mesons

We apply the diabatic formalism, first introduced in molecular physics, to the description of heavy-quark mesons. In this formalism the dynamics is completely described by a diabatic potential matrix whose elements can be derived from unquenched lattice QCD studies of string breaking. For energies far below the lowest open flavor meson-meson threshold, the resulting diabatic approach reduces to the well-known Born-Oppenheimer approximation where heavy-quark meson masses correspond to energy levels in an effective quark-antiquark potential. For energies close below or above that threshold, where the Born-Oppenheimer approximation fails, this approach provides a set of coupled Schrödinger equations incorporating meson-meson components nonperturbatively, i.e., beyond loop corrections. A spectral study of heavy mesons containing c ¯ c with masses below 4.1 GeV is carried out within this framework. From it a unified description of conventional as well as unconventional resonances comes out. DOI:
Network navigation using Page Rank random walks

We introduce a formalism based on a continuous time approximation, to study the characteristics of Page Rank random walks. We find that the diffusion of the occupancy probability has a dynamics that exponentially "forgets" the initial conditions and settles to a steady state that depends only on the characteristics of the network. In the special case in which the walk begins from a single node, we find that the largest eigenvalue of the transition value (lambda=1) does not contribute to the dynamic and that the probability is constant in the direction of the corresponding eigenvector. We study the process of visiting new node, which we find to have a dynamic similar to that of the occupancy probability. Finally, we determine the average transit time between nodes , which we find to exhibit certain connection with the corresponding time for Levy walks. The relevance of these results reside in that Page Rank, which are a more reasonable model for the searching behavior of individuals, can be shown to exhibit features similar to Levy walks, which in turn have been shown to be a reasonable model of a common large scale search strategy known as "Area Restricted Search".
Isolation of canine parvovirus in CRFK cell line from faecal samples of diarrhoeic dogs

A total of 178 faecal samples from diarrhoeic dogs were subjected to sandwich ELISA for detection of canine parvovirus (CPV) and 45 samples were found positive. Fifteen random faecal samples positive in sandwich ELISA were inoculated in CRFK cell line for isolation of the virus and 8 (53.33%), 10 (66.67%) and 11 (73.33%) samples were positive for CPV in first, second and third passage, respectively. All the 11 cell culture isolates did not show any cytopathic effect (CPE) in cell monolayer up to third passage.
Inverse energy transfer in decaying, three dimensional, nonhelical magnetic turbulence due to magnetic reconnection

It has been recently shown numerically that there exists an inverse transfer of magnetic energy in decaying, nonhelical, magnetically dominated, magnetohydrodynamic turbulence in 3-dimensions (3D). We suggest that magnetic reconnection is the underlying physical mechanism responsible for this inverse transfer. In the two-dimensional (2D) case, the inverse transfer is easily inferred to be due to smaller magnetic islands merging to form larger ones via reconnection. We find that the scaling behaviour is similar between the 2D and the 3D cases, i.e., the magnetic energy evolves as t−1, and the magnetic power spectrum follows a slope of k−2. We show that on normalizing time by the magnetic reconnection timescale, the evolution curves of the magnetic field in systems with different Lundquist numbers collapse onto one another. Furthermore, transfer function plots show signatures of magnetic reconnection driving the inverse transfer. We also discuss the conserved quantities in the system and show that the behaviour of these quantities is similar between the 2D and 3D simulations, thus making the case that the dynamics in 3D could be approximately explained by what we understand in 2D. Lastly, we also conduct simulations where the magnetic field is subdominant to the flow. Here, too, we find an inverse transfer of magnetic energy in 3D. In these simulations, the magnetic energy evolves as t−1.4 and, interestingly, a dynamo effect is observed.
Downsampling for Testing and Learning in Product Distributions

We study the domain reduction problem of eliminating dependence on $n$ from the complexity of property testing and learning algorithms on domain $[n]^d$, and the related problem of establishing testing and learning results for product distributions over $\mathbb{R}^d$. Our method, which we call downsampling, gives conceptually simple proofs for several results: 1. A 1-page proof of the recent $o(d)$-query monotonicity tester for the hypergrid (Black, Chakrabarty & Seshadhri, SODA 2020), and an improvement from $O(d^7)$ to $\widetilde O(d^4)$ in the sample complexity of their distribution-free monotonicity tester for product distributions over $\mathbb{R}^d$; 2. An $\exp(\widetilde O(kd))$-time agnostic learning algorithm for functions of $k$ convex sets in product distributions; 3. A polynomial-time agnostic learning algorithm for functions of a constant number of halfspaces in product distributions; 4. A polynomial-time agnostic learning algorithm for constant-degree polynomial threshold functions in product distributions; 5. An $\exp(\widetilde O(k \sqrt d))$-time agnostic learning algorithm for $k$-alternating functions in product distributions.
Hay Transfer Promotes Establishment of Mediterranean Steppe Vegetation on Soil Disturbed by Pipeline Construction

The Coussouls de Crau Nature Reserve is a xeric steppe providing a habitat for remarkable animals. Over the past centuries, this steppe has been partly destroyed and fragmented and has been reduced to 9,500 ha out of the 55,000 ha existing before the 16th century. Although this ecosystem is protected, 23 ha of natural habitat were nonetheless destroyed in 2006 during the construction of an underground pipeline. To mitigate potential future damage, an original experiment in restoration ecology was adapted and tested: the technique of hay transfer. The objective of this experiment was to find ways of accelerating steppe vegetation colonization on the soil over the buried pipelines by the reintroduction of steppe species. A factorial experiment was set up to test the effects of habitat characteristics, grazing, and hay transfer. The results obtained for 3 years after the experimentation setup are conclusive in favor of using hay transfer for the restoration of Mediterranean steppe ecosystem. Hay transfer has significantly increased the species richness on restored areas and has allowed the reintroduction of some typical steppe species. Among these species, we found a wide variety of annual grasses which play a key role in the recovery of steppe vegetation and provide food for sheep flocks. Sheep herding must be maintained during the ecological restoration of the herbaceous steppe community, because grazing significantly increases species richness on restored areas without changing species assemblies.
Definable completeness of P-minimal fields and applications

We show that every definable nested family of closed and bounded subsets of a [Formula: see text]-minimal field [Formula: see text] has nonempty intersection. As an application we answer a question of Darnière and Halupczok showing that [Formula: see text]-minimal fields satisfy the “extreme value property”: for every closed and bounded subset [Formula: see text] and every interpretable continuous function [Formula: see text] (where [Formula: see text] denotes the value group), [Formula: see text] admits a maximal value. Two further corollaries are obtained as a consequence of their work. The first one shows that every interpretable subset of [Formula: see text] is already interpretable in the language of rings, answering a question of Cluckers and Halupczok. This implies in particular that every [Formula: see text]-minimal field is polynomially bounded. The second one characterizes those [Formula: see text]-minimal fields satisfying a classical cell preparation theorem as those having definable Skolem functions, generalizing a result of Mourgues.
AdvFlow: Inconspicuous Black-box Adversarial Attacks using Normalizing Flows

Deep learning classifiers are susceptible to well-crafted, imperceptible variations of their inputs, known as adversarial attacks. In this regard, the study of powerful attack models sheds light on the sources of vulnerability in these classifiers, hopefully leading to more robust ones. In this paper, we introduce AdvFlow: a novel black-box adversarial attack method on image classifiers that exploits the power of normalizing flows to model the density of adversarial examples around a given target image. We see that the proposed method generates adversaries that closely follow the clean data distribution, a property which makes their detection less likely. Also, our experimental results show competitive performance of the proposed approach with some of the existing attack methods on defended classifiers, outperforming them in both the number of queries and attack success rate. The code is available at this https URL.
Strong connection between single-particle and density excitations in Bose–Einstein condensates

Strong connection between the single-particle excitation and the collective excitation stands out as one of the features of Bose–Einstein condensates (BECs). We discuss theoretically these single-particle and density excitations of BECs focusing on the exact properties of the one-body and two-body Green’s functions developed by Gavoret and Nozières. We also investigate these excitations by using the many-body approximation theory at nonzero temperatures. First, we revisited the earlier study presented by Gavoret and Nozières, involving the subsequent results given by Nepomnyashchii and Nepomnyashchii, in terms of the matrix formalism representation. This matrix formalism is an extension of the Nambu representation for the single-particle Green’s function of BECs to discuss the density and current response functions efficiently. We describe the exact low-energy properties of the correlation functions and the vertex functions, and discuss the correspondence of the spectra between the single-particle excitation and the density excitation in the low-energy and low-momentum limits at T = 0. After deriving the exact low-energy structures of the one-body and two-body Green’s functions, we develop a many-body approximation theory of BECs with making the use of the matrix formalism for describing the single-particle Green’s function and the density response function at nonzero temperatures. We show how the peaks of the single-particle spectral function and the density response function behave with an increasing temperature. Many-body effect on the single-particle spectral function and the density response function is included within a random phase approximation, where satellite structures emerge because of beyond-mean-field effects. Criticisms are also made on recent theories casting doubt upon the conventional wisdom of the BEC: the equivalence of the dispersion relations between the single-particle excitation and the collective excitation in the low-energy and low-momentum regime.
Statistical Evaluation of Medical Tests

In this review, we present an overview of the main aspects related to the statistical evaluation of medical tests for diagnosis and prognosis. Measures of diagnostic performance for binary tests, such as sensitivity, specificity, and predictive values, are introduced, and extensions to the case of continuous-outcome tests are detailed. Special focus is placed on the receiver operating characteristic (ROC) curve and its estimation, with emphasis on the topic of covariate adjustment. The extension to the case of time-dependent ROC curves for evaluating prognostic accuracy is also touched upon. We apply several of the approaches described to a data set derived from a study aimed to evaluate the ability of homeostasis model assessment of insulin resistance (HOMA-IR) levels to identify individuals at high cardio-metabolic risk and how such discriminatory ability might be influenced by age and gender. We also outline software available for the implementation of the methods.
Learning Invariances for Interpretability using Supervised VAE

We propose to learn model invariances as a means of interpreting a model. This is motivated by a reverse engineering principle. If we understand a problem, we may introduce inductive biases in our model in the form of invariances. Conversely, when interpreting a complex supervised model, we can study its invariances to understand how that model solves a problem. To this end we propose a supervised form of variational auto-encoders (VAEs). Crucially, only a subset of the dimensions in the latent space contributes to the supervised task, allowing the remaining dimensions to act as nuisance parameters. By sampling solely the nuisance dimensions, we are able to generate samples that have undergone transformations that leave the classification unchanged, revealing the invariances of the model. Our experimental results show the capability of our proposed model both in terms of classification, and generation of invariantly transformed samples. Finally we show how combining our model with feature attribution methods it is possible to reach a more fine-grained understanding about the decision process of the model.
On Indexing and Compressing Finite Automata

An index for a finite automaton is a powerful data structure that supports locating paths labeled with a query pattern, thus solving pattern matching on the underlying regular language. In this paper, we solve the long-standing problem of indexing arbitrary finite automata. Our solution consists in finding a partial co-lexicographic order of the states and proving, as in the total order case, that states reached by a given string form one interval on the partial order, thus enabling indexing. We provide a lower bound stating that such an interval requires $O(p)$ words to be represented, $p$ being the order's width (i.e. the size of its largest antichain). Indeed, we show that $p$ determines the complexity of several fundamental problems on finite automata: (i) Letting $\sigma$ be the alphabet size, we provide an encoding for NFAs using $\lceil\log \sigma\rceil + 2\lceil\log p\rceil + 2$ bits per transition and a smaller encoding for DFAs using $\lceil\log \sigma\rceil + \lceil\log p\rceil + 2$ bits per transition. This is achieved by generalizing the Burrows-Wheeler transform to arbitrary automata. (ii) We show that indexed pattern matching can be solved in $\tilde O(m\cdot p^2)$ query time on NFAs. (iii) We provide a polynomial-time algorithm to index DFAs, while matching the optimal value for $ p $. On the other hand, we prove that the problem is NP-hard on NFAs. (iv) We show that, in the worst case, the classic powerset construction algorithm for NFA determinization generates an equivalent DFA of size $2^p(n-p+1)-1$, where $n$ is the number of NFA's states.
Transport of Tritiated Water and 14C-Labelled Assimilate Into Grains of Wheat. II. Independence of Entry of 14c-Labelled Assimilate and THO

The mechanism involved in the transport of assimilates through the stalk by which the grain is attached to the rachilla has been investigated. Based on the presumption of pressure-driven mass flow, treatments designed to inhibit the import of assimilates would be expected to inhibit also the entry of water into the grain. Detached ears were supplied with solutions of [14C]sucrose in tritiated water (THO), and ears attached to the plant were watered with THO and supplied with 14CO2. The rachilla was heated by contact with a hot wire, and the stalk by steam-girdling. In addition, dinitrophenol (DNP) was used as an inhibitor of metabolically linked transport mechanisms. Heating or treatment with DNP reduced the transport of [14C]sucrose or [14C]-labelled assimilate into the grain, but the entry of THO was not reduced even by treatments which abolished altogether the transport of 14C into the grain. These results cannot be reconciled with mass flow as the means of transporting assimilates through the stalk of the wheat grain during grain filling.
New Knodus (Ostariophysi: Characiformes: Characidae) from the Upper Rio Paraguay Basin, Brazil

Abstract A new Knodus is described from the rio do Peixe, a tributary of the rio Cabaçal, in the upper portions of the rio Paraguay basin in Mato Grosso state, Brazil. It can be distinguished from its congeners, and in fact from all remaining characid fishes, by the presence of two symmetric, large dark blotches basally on caudal fin lobes. Comments on the disputed recognition of the genus Knodus are provided.
Metastability for expanding bubbles on a sticky substrate

We study the dynamical behavior of a one dimensional interface interacting with a sticky unpenetrable substrate or wall. The interface is subject to two effects going in opposite directions. Contact between the interface and the substrate are given an energetic bonus while an external force with constant intensity pulls the interface away from the wall. Our interface is modeled by the graph of a one-dimensional nearest-neighbor path on $\mathbb{Z}_+$, starting at $0$ and ending at $0$ after $2N$ steps, the wall corresponding to level-zero the horizontal axis. At equilibrium each path $\xi=(\xi_x)_{x=0}^{2N}$, is given a probability proportional to $\lambda^{H(\xi)} \exp(\frac{\sigma}{N}A(\xi))$, where $H(\xi):=\#\{x \ : \xi_x=0\}$ and $A(\xi)$ is the area enclosed between the path $\xi$ and the $x$-axis. We then consider the classical heat-bath dynamics which equilibrates the value of each $\xi_x$ at a constant rate via corner-flip. Investigating the statics of the model, we derive the full phase diagram in $\lambda$ and $\sigma$ of this model, and identify the critical line which separates a localized phase where the pinning force sticks the interface to the wall and a delocalized one, for which the external force stabilizes $\xi$ around a deterministic shape at a macroscopic distance of the wall. On the dynamical side, we identify a second critical line, which separates a rapidly mixing phase (for which the system mixes in polynomial time) to a slow phase where the mixing time grows exponentially. In this slowly mixing regime we obtain a sharp estimate of the mixing time on the $\log$ scale, and provide evidences of a metastable behavior.
Multivariate white matter alterations are associated with epilepsy duration

Previous studies investigating associations between white matter alterations and duration of temporal lobe epilepsy (TLE) have shown differing results, and were typically limited to univariate analyses of tracts in isolation. In this study, we apply a multivariate measure (the Mahalanobis distance), which captures the distinct ways white matter may differ in individual patients, and relate this to epilepsy duration. Diffusion MRI, from a cohort of 94 subjects (28 healthy controls, 33 left‐TLE and 33 right‐TLE), was used to assess the association between tract fractional anisotropy (FA) and epilepsy duration. Using ten white matter tracts, we analysed associations using the traditional univariate analysis (z‐scores) and a complementary multivariate approach (Mahalanobis distance), incorporating multiple white matter tracts into a single unified analysis. For patients with right‐TLE, FA was not significantly associated with epilepsy duration for any tract studied in isolation. For patients with left‐TLE, the FA of two limbic tracts (ipsilateral fornix, contralateral cingulum gyrus) were significantly negatively associated with epilepsy duration (Bonferonni corrected p < .05). Using a multivariate approach we found significant ipsilateral positive associations with duration in both left, and right‐TLE cohorts (left‐TLE: Spearman's ρ = 0.487, right‐TLE: Spearman's ρ = 0.422). Extrapolating our multivariate results to duration equals zero (i.e., at onset) we found no significant difference between patients and controls. Associations using the multivariate approach were more robust than univariate methods. The multivariate Mahalanobis distance measure provides non‐overlapping and more robust results than traditional univariate analyses. Future studies should consider adopting both frameworks into their analysis in order to ascertain a more complete understanding of epilepsy progression, regardless of laterality.
The effect of elevated UV‐B radiation on herbivory of pea by Autographa gamma

Leaves exposed to above‐ambient fluxes of ultraviolet‐B (UV‐B) radiation commonly contain increased concentrations of phenolic compounds which may influence herbivores. However, the hypothesis that elevated UV‐B modifies herbivory, whether mediated by phenolics or other plant constituents, has rarely been studied experimentally. We investigated the responses of the moth Autographa gamma L. (Lepidoptera: Noctuidae) to pea (Pisum sativum L.) grown at a range of plant‐effective UV‐B fluxes. Although total phenolics did increase significantly with increasing UV‐B, this change had little deleterious effect on the 5th instar larvae of A. gamma. However, tissue nitrogen also increased with increasing UV‐B. Increased nitrogen was correlated with an increase in the efficiency with which larvae utilized their food and in larval growth rate, but in a reduction in the amount of plant material consumed. The apparently major role of nitrogen in determining herbivore responses to changing UV‐B demonstrates the risks in predicting such responses soley on the basis of changes in phenolics and other secondary metabolites.