Miracle-dz/UniFAR-FTUs huggingface dataset:
Dynamical analysis of cosmological models with non-Abelian gauge vector fields

In this paper we study some models where non-Abelian gauge vector fields endowed with a SU(2) group representation are the unique source of inflation and dark energy. These models were first introduced under the name of gaugeflation and gaugessence, respectively. Although several realizations of these models have been discussed, not all available parameters and initial conditions are known. In this work, we use a dynamical system approach to find the full parameter space of the massive version of each model. In particular, we found that the inclusion of the mass term increases the length of the inflationary period. Additionally, the mass term implies new behaviors for the equation of state of dark energy allowing to distinguish this from other prototypical models of accelerated expansion. We show that an axially symmetric gauge field can support an anisotropic accelerated expansion within the observational bounds.
Isotopic invisibility of protozoan trophic steps in marine food webs

According to modern oceanographic perspectives that emphasize microbial pathways, phagotrophic protists comprise one to several levels of intermediate consumers between phytoplankton and larger metazooplankton (copepods and krill). However, recent attempts to quantify pelagic trophic structure in the open ocean using nitrogen stable isotope techniques have brought into question whether such measurements adequately account for protistan trophic steps. Here, we use a two‐stage chemostat system, with Dunaliella tertiolecta and Oxyrrhis marina as a predator—prey model, to address this question experimentally. To investigate 15N trophic discrimination under different conditions of nitrogen availability and recycling, Oxyrrhis was fed in the light and in the dark on phytoplankton provided with high and low nutrient ratios of N : P. We used both bulk and amino acids—compound specific isotopic analysis (AA—CSIA) to distinguish trophic fractionation from changes in the δ15N values of phytoplankton (isotopic baseline). Results demonstrate that protistan consumers are not, in fact, significantly enriched in 15N relative to their prey, a marked departure from the general findings for metazoan consumers. In addition, we show that changes in the isotopic baseline propagate rapidly through the protistan food chain, highlighting the need to account for this variability at ecologically relevant time scales. If protistan trophic steps are largely invisible or significantly underestimated using nitrogen isotope measurements, research that utilize such measurements in ecological, fisheries, and climate change studies may miss a large part of the ocean's variability in food‐web structure and ecosystem function.
The Interpolation Phase Transition in Neural Networks: Memorization and Generalization under Lazy Training

Modern neural networks are often operated in a strongly overparametrized regime: they comprise so many parameters that they can interpolate the training set, even if actual labels are replaced by purely random ones. Despite this, they achieve good prediction error on unseen data: interpolating the training set does not induce overfitting. Further, overparametrization appears to be beneficial in that it simplifies the optimization landscape. Here we study these phenomena in the context of two-layers neural networks in the neural tangent (NT) regime. We consider a simple data model, with isotropic feature vectors in $d$ dimensions, and $N$ hidden neurons. Under the assumption $N \le Cd$ (for $C$ a constant), we show that the network can exactly interpolate the data as soon as the number of parameters is significantly larger than the number of samples: $Nd\gg n$. Under these assumptions, we show that the empirical NT kernel has minimum eigenvalue bounded away from zero, and characterize the generalization error of min-$\ell_2$ norm interpolants, when the target function is linear. In particular, we show that the network approximately performs ridge regression in the raw features, with a strictly positive `self-induced' regularization.
Formation of Population II Star Clusters in the Aftermath of a Pair Instability Supernova

Population II (Pop II) stars formed a few hundred million years after the Big Bang were key drivers of cosmic reionization and building blocks of high-redshift galaxies. How and when these stars formed is a subject of ongoing research. We conduct cosmological radiation hydrodynamical simulations to investigate the formation of Pop II star clusters in dark matter halos forming at z = 10–25 in the aftermath of a pair instability supernova (PISN). Our simulations model the formation of Population III and Pop II stars in a self-consistent manner along with their radiative, chemical, and SN feedback in halos of 5 × 105–7 × 107 M⊙. We find that a PISN evacuates the gas from halos ≤3 × 106 M⊙ and thereafter shuts off in situ star formation for at least 30 Myr. Pop II stellar clusters of 923 M⊙ and 6800 M⊙ form in halos of 3.8 × 107 M⊙ and 9 × 107 M⊙, respectively. The mode of star formation is highly episodic and mainly regulated by Pop II SN feedback. The average star formation rates are 10−5–10−4 M⊙ yr−1, and the star formation efficiency is less than 1%.
Evolution of Free Amino Acids during the Ripening of Cheddar Cheese Containing Added Lactobacilli Strains

Cheddar cheese was produced with different lactobacilli strains added to accelerate ripening. The concentration of proteolytic products was determined as free amino acids in the water-soluble fraction at two, four, seven and nine months of aging and at two different maturation temperatures (6°C, 15°C). All amino acids increased during ripening and were higher in the Lactobacillus- added cheeses than in the control cheese, and higher in cheeses ripened at 15°C than at 6°C. Glutamic acid, leucine, phenylalanine, valine and lysine were generally in higher proportion in all cheeses. The cheeses with added L. casei-casei L2A were classified as having a “strong Cheddar cheese” flavor after only seven months of ripening at 6°C.
Stabilizing Bi-Level Hyperparameter Optimization using Moreau-Yosida Regularization

This research proposes to use the Moreau-Yosida envelope to stabilize the convergence behavior of bi-level Hyperparameter optimization solvers, and introduces the new algorithm called Moreau-Yosida regularized Hyperparameter Optimization (MY-HPO) algorithm. Theoretical analysis on the correctness of the MY-HPO solution and initial convergence analysis is also provided. Our empirical results show significant improvement in loss values for a fixed computation budget, compared to the state-of-art bi-level HPO solvers.
Minimum Overhead Beamforming and Resource Allocation in D2D Edge Networks

Device-to-device (D2D) communications is expected to be a critical enabler of distributed computing in edge networks at scale. A key challenge in providing this capability is the requirement for judicious management of the heterogeneous communication and computation resources that exist at the edge to meet processing needs. In this paper, we develop an optimization methodology that considers the network topology jointly with device and network resource allocation to minimize total D2D overhead, which we quantify in terms of time and energy required for task processing. Variables in our model include task assignment, CPU allocation, subchannel selection, and beamforming design for multiple-input multiple-output (MIMO) wireless devices. We propose two methods to solve the resulting non-convex mixed integer program: semi-exhaustive search optimization, which represents a “best-effort” at obtaining the optimal solution, and efficient alternate optimization, which is more computationally efficient. As a component of these two methods, we develop a novel coordinated beamforming algorithm which we show obtains the optimal beamformer for a common receiver characteristic. Through numerical experiments, we find that our methodology yields substantial improvements in network overhead compared with local computation and partially optimized methods, which validates our joint optimization approach. Further, we find that the efficient alternate optimization scales well with the number of nodes, and thus can be a practical solution for D2D computing in large networks.
Evaluating the reliability of acoustic speech embeddings

Speech embeddings are fixed-size acoustic representations of variable-length speech sequences. They are increasingly used for a variety of tasks ranging from information retrieval to unsupervised term discovery and speech segmentation. However, there is currently no clear methodology to compare or optimise the quality of these embeddings in a task-neutral way. Here, we systematically compare two popular metrics, ABX discrimination and Mean Average Precision (MAP), on 5 languages across 17 embedding methods, ranging from supervised to fully unsupervised, and using different loss functions (autoencoders, correspondence autoencoders, siamese). Then we use the ABX and MAP to predict performances on a new downstream task: the unsupervised estimation of the frequencies of speech segments in a given corpus. We find that overall, ABX and MAP correlate with one another and with frequency estimation. However, substantial discrepancies appear in the fine-grained distinctions across languages and/or embedding methods. This makes it unrealistic at present to propose a task-independent silver bullet method for computing the intrinsic quality of speech embeddings. There is a need for more detailed analysis of the metrics currently used to evaluate such embeddings.
Topographic maps applied to comparative molar morphology: the case of murine and cricetine dental plans (Rodentia, Muroidea)

Abstract We developed a new method to generate topographic maps of tooth crowns from X-ray synchrotron microtomographic data. Maps are drawn after cervix-plane orientation of tooth image stacks, without the need for a geographic information system. Classical topographic maps with contour lines are complemented by slope maps and angularity maps. Cartography allows precise comparisons of cusps morphologies, and quantification of the directions of cusp axis elongation and slope. Application of this method to muroid rodents with cricetine and murine dental patterns reveals clear-cut differences in cusps morphology that are indicative of the direction of the chewing movement, in agreement with wear facet analyses. Rodents with a murine dental pattern were derived from ancestors with a cricetine pattern, and their origin is associated with important changes in cusp morphology and organization. In order to understand such evolutionary change, our investigation is applied to a sample of extant and fossil muroid rodents that are characterized by either a murine dental plan or a cricetine one, or a dental pattern intermediate between those of cricetines and murines.
Existence and symmetry of solutions to 2-D Schrödinger–Newton equations

In this paper, we consider the following 2-D Schr\"{o}dinger-Newton equations \begin{eqnarray*} -\Delta u+a(x)u+\frac{\gamma}{2\pi}\left(\log(|\cdot|)*|u|^p\right){|u|}^{p-2}u=b{|u|}^{q-2}u \qquad \text{in} \,\,\, \mathbb{R}^{2}, \end{eqnarray*} where $a\in C(\mathbb{R}^{2})$ is a $\mathbb{Z}^{2}$-periodic function with $\inf_{\mathbb{R}^{2}}a>0$, $\gamma>0$, $b\geq0$, $p\geq2$ and $q\geq 2$. By using ideas from \cite{CW,DW,Stubbe}, under mild assumptions, we obtain existence of ground state solutions and mountain pass solutions to the above equations for $p\geq2$ and $q\geq2p-2$ via variational methods. The auxiliary functional $J_{1}$ plays a key role in the cases $p\geq3$. We also prove the radial symmetry of positive solutions (up to translations) for $p\geq2$ and $q\geq 2$. The corresponding results for planar Schr\"{o}dinger-Poisson systems will also be obtained. Our theorems extend the results in \cite{CW,DW} from $p=2$ and $b=1$ to general $p\geq2$ and $b\geq0$.
Sequestration, migration and lysis of protozoa in the rumen

Summary: A container with nylon and stainless steel mesh screens (10 μm and 20 μm pores, respectively), which allowed the passage of bacteria and soluble substrate but restricted the passage of protozoa, was used to investigate the phenomena of sequestration, migration and lysis of protozoa in the rumen of steers. After feeding, the concentration of Isotrichidae in the rumen increased 8·7-fold within 40 min and then decreased 88% by 4h; however, the concentration of Isotrichidae inside the containers remained almost constant. Fluctuations in concentrations of Isotrichidae were shown to be due to migration and sequestration within the rumen. Ophryoscolecidae did not exhibit the phenomena of sequestration and migration. When steers were fed once a day, about 50% of the decrease in the concentration of Ophryoscolecidae immediately after feeding could be attributed to the dilution effects of feed and water and/or passage out of the rumen. The remaining 50% of the decrease appeared to be from cell lysis, resulting in a wasteful recycling of protozoal protein. In an experiment to determine the effects of feed restriction on concentrations of Ophryoscolecidae, it was shown that decreased concentrations associated with substrate restriction are due to cell lysis rather than to passage out of the rumen.
Counterfactual Evaluation of Slate Recommendations with Sequential Reward Interactions

Users of music streaming, video streaming, news recommendation, and e-commerce services often engage with content in a sequential manner. Providing and evaluating good sequences of recommendations is therefore a central problem for these services. Prior reweighting-based counterfactual evaluation methods either suffer from high variance or make strong independence assumptions about rewards. We propose a new counterfactual estimator that allows for sequential interactions in the rewards with lower variance in an asymptotically unbiased manner. Our method uses graphical assumptions about the causal relationships of the slate to reweight the rewards in the logging policy in a way that approximates the expected sum of rewards under the target policy. Extensive experiments in simulation and on a live recommender system show that our approach outperforms existing methods in terms of bias and data efficiency for the sequential track recommendations problem.
Tarsal contact chemoreceptor response to glucosinolates and cardenolides mediating oviposition in Pieris rape

Abstract. Water‐soluble extracts of a host crucifer (Brassica oleracea L.) and non‐host crucifer (Erysimum cheiranthoides L.) and isolated pure cardenolides and glucosinolates were tested on Pieris rapae L. (Lepidoptera: Pieridae) butterflies in oviposition assays and by electrophysiological recordings from the contact‐chemoreceptor sensilla of the prothoracic tarsi.
A Simple and Interpretable Predictive Model for Healthcare

Deep Learning based models are currently dominating most state-of-the-art solutions for disease prediction. Existing works employ RNNs along with multiple levels of attention mechanisms to provide interpretability. These deep learning models, with trainable parameters running into millions, require huge amounts of compute and data to train and deploy. These requirements are sometimes so huge that they render usage of such models as unfeasible. We address these challenges by developing a simpler yet interpretable non-deep learning based model for application to EHR data. We model and showcase our work's results on the task of predicting first occurrence of a diagnosis, often overlooked in existing works. We push the capabilities of a tree based model and come up with a strong baseline for more sophisticated models. Its performance shows an improvement over deep learning based solutions (both, with and without the first-occurrence constraint) all the while maintaining interpretability.
Don’t Fish in Troubled Waters! Characterizing Coronavirus-themed Cryptocurrency Scams

As COVID-19 has been spreading across the world since early 2020, a growing number of malicious campaigns are capitalizing the topic of COVID-19. COVID-19 themed cryptocurrency scams are increasingly popular during the pandemic. However, these newly emerging scams are poorly understood by our community. In this paper, we present the first measurement study of COVID-19 themed cryptocurrency scams. We first create a comprehensive taxonomy of COVID-19 scams by manually analyzing the existing scams reported by users from online resources. Then, we propose a hybrid approach to perform the investigation by: 1) collecting reported scams in the wild; and 2) detecting undisclosed ones based on information collected from suspicious entities (e.g., domains, tweets, etc). We have collected 195 confirmed COVID-19 cryptocurrency scams in total, including 91 token scams, 19 giveaway scams, 9 blackmail scams, 14 crypto malware scams, 9 Ponzi scheme scams, and 53 donation scams. We then identified over 200 blockchain addresses associated with these scams, which lead to at least 330K US dollars in losses from 6,329 victims. For each type of scams, we further investigated the tricks and social engineering techniques they used. To facilitate future research, we have released all the well-labelled scams to the research community.
Efficacy of Piper guineense (Schum & Thonn) seed extract against maize weevil, Sitophilus zeamais (Motschulsky) as influenced by different extraction solvents

Abstract The seed extract of black pepper Piper guineense Schum & Thonn was evaluated for its biological activity against the maize weevil Sitophilus zeamais Motschulsky at 30°C, 65 ± 2% R.H and 12:12-h light:dark regimes in the laboratory. The different solvents used for the extraction were acetone, ethanol, n-hexane, petroleum ether (60:80) and distilled water at 0.3% dosage level. The acetone extract had the highest toxicity (100%), while the control showed no toxicity at 28 days post treatment. All of the treatments significantly reduced adult emergence and grain damage compared with the control. Grain germination with the solvents was significantly higher than with the aqueous extract (49%), which was significantly superior to the control (39%). Piper guineense extract with the different organic solvents caused acute mortality in S. zeamais adults.
Generalized General Relativistic Magnetohydrodynamic Equations for Plasmas of Active Galactic Nuclei in the Era of the Event Horizon Telescope

The generalized general relativistic magnetohydrodynamic (generalized GRMHD) equations have been used to study specific relativistic plasma phenomena, such as relativistic magnetic reconnection or wave propagation modified by nonideal MHD effects. However, the Θ term in the generalized Ohm’s law, which expresses the energy exchange between two fluids composing a plasma, has yet to be determined in these equations. In this paper, we determine the Θ term based on the generalized relativistic Ohm’s law itself. This provides closure of the generalized GRMHD equations, yielding a closed system of the equations of relativistic plasma. According to this system of equations, we reveal the characteristic scales of nonideal MHD phenomena and clarify the applicable condition of the ideal GRMHD equations. We evaluate the characteristic scales of the nonideal MHD phenomena in the M87* plasma using the Event Horizon Telescope observational data.
Clinical significance of miR-372 and miR-495 in acute myeloid leukemia

The present study aimed to explore the clinical significance of miR-372 and miR-495 in acute myeloid leukemia (AML). Eighty-one AML patients (research group) admitted to the First Hospital of Lanzhou University from March 2012 to January 2014 were selected, and 60 healthy persons (control group) were selected. The expression levels of miR-372 and miR-495 in the peripheral blood of the subjects were detected by reverse transcriptase quantitative PCR, and their diagnostic and prognostic values in AML were analyzed. The miR-372 expression level in the peripheral blood of patients in the research group was significantly higher than that in the control group (P<0.05), and the miR-495 level was significantly lower than that in the control group (P<0.05). The area under the curve (AUC), sensitivity, and specificity of miR-372 combined with miR-495 in the diagnosis of AML were 0.925, 86.43, and 93.33% respectively. The 5-year survival rate of patients with high expression of miR-372 was lower than that of those with low expression of miR-372 (P<0.05), and the 5-year survival rate of patients with high expression of miR-495 was higher than that of those with low expression of miR-495 (P<0.05). miR-372 and miR-495 were independent risk factors for the prognosis and survival of AML patients. miR-372 expression increased in AML, while miR-495 decreased. miR-372 and miR-495 are effective indicators for the early diagnosis and prognosis of AML.
Patterns of host–parasite associations in tropical lice and their passerine hosts in Cameroon

Abstract Coevolutionary processes that drive the patterns of host–parasite associations can be deduced through congruence analysis of their phylogenies. Feather lice and their avian hosts have previously been used as typical model systems for congruence analysis; however, such analyses are strongly biased toward nonpasserine hosts in the temperate zone. Further, in the Afrotropical region especially, cospeciation studies of lice and birds are entirely missing. This work supplements knowledge of host–parasite associations in lice using cospeciation analysis of feather lice (genus Myrsidea and the Brueelia complex) and their avian hosts in the tropical rainforests of Cameroon. Our analysis revealed a limited number of cospeciation events in both parasite groups. The parasite–host associations in both louse groups were predominantly shaped by host switching. Despite a general dissimilarity in phylogeny for the parasites and hosts, we found significant congruence in host–parasite distance matrices, mainly driven by associations between Brueelia lice and passerine species of the Waxbill (Estrildidae) family, and Myrsidea lice and their Bulbul (Pycnonotidae) host species. As such, our study supports the importance of complex biotic interactions in tropical environments.