Miracle-dz/UniFAR-FTUs huggingface dataset:
Cosmological Applications of Gravitational Lensing

The discovery by Walsh et al (1979) of the first bona fide gravitational lens, the doubly-imaged quasar, Q0957 + 561, happened at an opportune time, following several prescient theoretical papers, and just preceding the completion of radio and optical quasar surveys that have since yielded over a dozen examples of this phenomenon. Interest in gravitational lenses stretches back over more than seventy years (Eddington 1919, Lodge 1919). Zwicky (1937a,b) appears to have been the first to realize that gravitational lensing ought to have a major impact on cosmology, specifically by "weighing" nebulae and providing crude telescopes to magnify lensed sources. The discovery of quasi-stellar "point" sources added two more possible uses of lenses, for distance measurement (Klimov 1963, Liebes 1964, Refsdal 1964b) and as probes of the stellar composition of lenses (Chang & Refsdal 1979), both of which may be just coming to fruition. These four topics constitute the primary theme of this review.
Mode selective properties of coaxial gyrotron resonators

In this paper, the mode-selective properties of coaxial gyrotron resonators are discussed for different cavity configurations. Expressions are derived for the ohmic loading of a coaxial conductor with longitudinal corrugations where the RF field inside the corrugations is fully taken into account, and for the diffractive quality factor in coaxial cavities with tapered inner conductor relative to that of an empty cylindrical cavity. The competing action of a kind of "surface mode" that appears in corrugated structures is investigated by considering its diffractive and ohmic quality factors. Additional mode competition problems that can arise in coaxial cavities with corrugated inner conductor due to second cyclotron harmonic interaction are investigated and solutions to the problem are proposed.
Biological activity of soils cultivated with yacón (Smallanthus sonchifolius Poep. & Endl) H. Robinson, inoculated with Azospirillum brasilense and native mycorrhizal fungi

The soil is influenced by the roots of plants because the exudate radicals affect its physical, chemical, and biological processes. The aim of this research was to evaluate the microbial activity of soils cultivated with yacón (Smallanthus sonchifolius Poep. & Endl) H. Robinson and inoculated with microorganisms which promote plant growth. The experimental design used was randomized blocks with three repetitions per treatment. Each repetition corresponded to a 3 x 3m plot with 25 plants, in 5 cultivation lines with a distance of 70 cm apart. Four treatments were applied at the time of plantation. These consisted of yacón propagules inoculated with Azospirillum brasilense (T1) and native mycorrhizal fungi (T2) inoculated with the microbial consortium (T3). In the control treatments, the propagules were not inoculated with these microorganisms (T0). Soil samples were collected in lots cultivated with yacón located in the Province of Catamarca, in the northwest of Argentina. The samples were collected at the time of implantation and harvest during three agricultural cycles. The total Biological Activity (TBA) of the collected samples was determined by Fluorescein Diacetate Hydrolysis. The TBA of the soil was affected by the different crop treatments, which rose in the analyzed soils and was statistically different from the control treatments. Significant differences were also observed between the TBA of the soils at the beginning of the crops in comparison with the recorded values of the crop at the time of harvest. The inoculation of yacón propagules with A. brasilense and native mycorrhizal fungi affects the TBA of the cultivated soils marking a significant increase.
Transcutaneous and Direct Electrical Stimulation of Mouse Sciatic Nerve Accelerates Functional Recovery After Nerve Transection and Immediate Repair

Background Electrical stimulation can accelerate peripheral nerve regeneration after injury and repair. Clinically, direct electrical stimulation (DES) may involve longer operating times, increasing risks of perioperative complications. Transcutaneous electrical stimulation (TCES) is a noninvasive alternative. In this study, we investigate how transcutaneous and DES compare for accelerating functional nerve recovery in a mouse sciatic nerve model. Methods Twenty-eight mice were divided into sham (n = 4), axotomy (n = 8), DES (n = 8), and TCES (n = 8) groups. After sciatic nerve transection and repair, the proximal nerve was subjected to DES or TCES at 20 Hz for 1 hour. Sciatic functional index was measured before the injury, and at weeks 1, 2, 4, 6, 8, 10, and 12 by walking-track analysis. Electrophysiological measures were taken at week 12. Results Kinematic studies showed significant improvement from the 8th week to the 12th week for both electrical stimulation groups compared with the axotomy group (P < 0.05), with no difference between the electrical stimulation groups. At the 12th week, both DES and TCES groups had significantly faster average conduction velocity than the axotomy group. Conclusions Functional recovery was significantly better from 8 weeks onward in mice receiving either DES or TCES stimulation when compared with axotomy and repair alone. Transcutaneous electrical stimulation is a minimally invasive alternative treatment for accelerating functional recovery after peripheral nerve injury.
THE ROLES OF EXTRACELLULAR VESICLES IN SEPSIS AND SYSTEMIC INFLAMMATORY RESPONSE SYNDROME

ABSTRACT Sepsis is a life-threatening organ dysfunction, caused by dysregulation of the host response to infection. To understand the underlying mechanisms of sepsis, the vast spectrum of extracellular vesicles (EVs) is gaining importance in this research field. A connection between EVs and sepsis was shown in 1998 in an endotoxemia pig model. Since then, the number of studies describing EVs as markers and mediators of sepsis increased steadily. Extracellular vesicles in sepsis could be friends and foes at the same time depending on their origin and cargo. On the one hand, transfer of EVs or outer membrane vesicles can induce sepsis or systemic inflammatory response syndrome with comparable efficiency as well-established methods, such as cecal ligation puncture or lipopolysaccharide injection. On the other hand, EVs could provide certain therapeutic effects, mediated via reduction of reactive oxygen species, inflammatory cytokines and chemokines, influence on macrophage polarization and apoptosis, as well as increase of anti-inflammatory cytokines. Moreover, EVs could be helpful in the diagnosis of sepsis. Extracellular vesicles of different cellular origin, such as leucocytes, macrophages, platelets, and granulocytes, have been suggested as potential sepsis biomarkers. They ensure the diagnosis of sepsis earlier than classical clinical inflammation markers, such as C-reactive protein, leucocytes, or IL-6. This review summarizes the three roles of EVs in sepsis—mediator/inducer, biomarker, and therapeutic tool.
Contact temperature and erosion in high-current diffuse vacuum arcs on axial magnetic field contacts

We have investigated the surface heating effects of drawn vacuum arcs for several industrial designs of axial magnetic field (AMF) contacts, using near infrared (IR) photography of the Cu-Cr arcing surfaces with an image-intensified charge-coupled device (CCD) camera and an IR pyrometer. This enables detailed contact temperature mapping immediately after a half-cycle of arc current. The very homogeneous temperature distribution observed at current zero stands in contrast to the visually nonhomogeneous high-current diffuse arc, which was studied in separately reported experiments using high-speed digital photography and arc voltage measurements. The peak temperature at current zero increased relatively linearly with the peak current I/sub P/, and reached well beyond the melting range. We combine the temperature maps with a heating model to determine the thermal sheath thickness after arcing and its dependence on I/sub P/. The results suggest that near the interruption limit of AMF contacts, the interaction of the stable high-current arc with the anode and cathode is dominated by processes induced by flowing liquid metal, which redistributes the heat input from the axially concentrated arc over most of the contact surface. Furthermore, the flow of liquid metal off the cathode and anode faces contributes to the overall contact erosion.
Performance of some new preliminary test ridge regression estimators and their properties

The problem of estimation of the regression coefficients in a multiple regression model is considered under multicollinearity situation when it is suspected that the regression coefficients may be restricted to a subspace. We present the estimators of the regression coefficients combining the idea of preliminary test and ridge regression methodology. Accordingly, we consider three estimators, namely, the unrestricted ridge regression estimator (URRE), the restricted ridge regression estimator (RRRE), and finally, the preliminary test ridge regression estimator (PTRRE). The biases, variancematrices and mean square errors (mse) of the estimators are derived and compared with the usual estimators. Regions of optimality of the estimators are determined by studying the mse criterion. The conditions of superiority of the estimators over the traditional estimators as in Saleh and Han (1990) and Ali and Saleh (1991) have also been discussed.
Nonstationary spectral modeling of voiced speech

The main purpose of this paper is to present a novel model for voiced speech. The classical model, which is being used in many applications, assumes local stationarity, and consequently imposes a simple and well known line structure to the short-time spectrum of voiced speech. The model derived in this paper allows for local non-stationarities not only in terms of pitch perturbations, but in terms of vocal tract variations as well. The resulting structure of the short-time spectrum becomes more complex, but can still be interpreted in terms of generalized lines. The proposed model supports new forms of spectral prediction, which can be put to advantage in speech coding applications. Experimental results are presented supporting the validity of both the model itself and the prediction relationships. Finally, a new class of speech coders, denoted harmonic coders, based on the presented model, is proposed, and a specific implementation is presented.
Point-to-point regulation of a robot with flexible joints including electrical effects of actuator dynamics

This paper considers the set-point tracking problem in rigid and flexible-joint robots when both the mechanical as well as the electrical effects of the actuator dynamics are taken into account. The suggested controllers are based on state and output feedbacks. The current approach demonstrates that for every given desired operating point, linear state and output feedbacks with constant feedforwards can be constructed such that the closed-loop system is globally asymptotically stable.
Essential spectra and semigroups of perturbations of M-hypoelliptic pseudo-differential operators on L p (ℝ n )

Using a version of Erhling's inequality for L p -Sobolev spaces H s,p on ℝ n , −∞ < s < +∞, 1 ≤ p < ∞ given by Wong in his paper [M.W. Wong, Erhling's inequality and pseudo-differential operators on L p (ℝ n ), Cubo 8 (2006), pp. 97–108]. we establish an analogue of Agmon–Douglis–Nirenberg inequality for M-hypoelliptic pseudo-differential operators perturbed by singular potentials on L p (ℝ n ), 1 < p < ∞. We also state and prove some facts concerning the essential spectra of M-hypoelliptic pseudo-differential operators T σ on L p (ℝ n ), 1 < p < ∞, perturbed by the operators of the form . A self-adjointness result is also proved for such perturbations of M-hypoelliptic pseudo-differential operators on L 2(ℝ n ) whose symbols are independent of x in ℝ n . Moreover, as in the work [M.W. Wong, Erhling's inequality and pseudo-differential operators on L p (ℝ n ), Cubo 8 (2006), pp. 97–108] by Wong an application to strongly continuous semigroups of contractions generated by M-hypoelliptic pseudo-differential operators on L p (ℝ n ), 1 < p < ∞ is given.
Direct solution method for finite element analysis using Hopfield neural network

One property of the Hopfield neural network is the monotonous minimization of energy as time proceeds. In this paper, this property is applied to minimize the energy functional obtained by ordinary finite element analysis. The mathematical representation and correlation between finite element and neural network calculus are presented. The selection of the sigmoid function and its influence on the iteration process is discussed. The obtained results using the proposed method show excellent agreement with theoretical solutions. >
On the resonant nature of the breakdown of a laminar boundary layer

The first part of this paper (§2) briefly reviews the history of the idea of the resonant nature of laminar-boundary-layer breakdown. In the second part a new wave-resonance concept of the breakdown mechanism is proposed. The existing experimental data on the laminar boundary layer (and plane channel flow) breakdown are analysed from the viewpoint of this concept and are compared with the well-known local high-frequency secondary-instability concept. The results testify to the correctness of the proposed wave-resonant concept for the initial stages of breakdown, in particular for the K-regime of transition up to the spike formation and its doubling. Within the framework of the wave-resonance concept, before constructing the corresponding theory, many important features of the disturbance development can be qualitatively explained and understood. Concerning the understanding of the spike appearance, the wave-resonance concept complements the local high-frequency secondary-instability one and represents by itself a new fruitful viewpoint on this phenomenon. The development of the wave-resonance concept and its application to the analysis of numerical and physical experiments, together with the construction on this basis of the corresponding theory, can give an essential impetus towards the better understanding of the breakdown nature.
Fisher Kernels and Probabilistic Latent Semantic Models

Tasks that rely on semantic content of documents, notably Information Retrieval and Document Classification, can benefit from a good account of document context, i.e. the semantic association between documents. To this effect, the scheme of latent semantics blends individual words appearing throughout a document collection into latent topics, thus providing a way to handle documents that is less constrained than the conventional approach by the mere appearance of such or such word. Probabilistic latent semantic models take the matter further by providing assumptions on how the documents observed in the collection would have been generated. This allows derivation of inference algorithms that can fit the model parameters to the observed document collection; with their values set, these parameters can then be used to compute the similarities between documents. The Fisher kernels, similarity functions rooted in information geometry, constitute good candidates to measure the similarity between documents in the framework of probabilistic latent semantic models. In this context, we study the use of Fisher kernels for the Probabilistic Latent Semantic Indexing (PLSI) model. By thoroughly analysing the generative process of PLSI, we derive the proper Fisher kernel for PLSI and expose the hypotheses that relate former work to this kernel. In particular, we confirm that the Fisher information matrix (FIM) should not be approximated by the identity in the case of PLSI. We also study the impact on the performances of the Fisher kernel of the contribution of the latent topics and the one of the distribution of words among the topics; eventually, we provide empirical evidence, and theoretical arguments, showing that the Fisher kernel originally published by Hofmann, corrected to account for FIM, is the best of the PLSI Fisher kernels. It can compete with the strong BM25 baseline, and even significantly outperforms it when documents sharing few words must be matched. We further study of PLSI document similarities by applying the Language model approach. This approach shuns the usual IR paradigm that considers documents and queries to be of a similar nature. Instead, they consider documents as being representative of language models, and use probabilistic tools to determine which of these models would have generated the query with highest probability. Using this scheme in the framework of PLSI provides a way to bypass the issue of query representation, which constitutes one of the specific challenges of PLSI. We find the Language model approach to perform as well as the best of the Fisher kernels when enough latent categories are provided. Eventually, we propose a new probabilistic latent semantic model consisting in a mixture of Smoothed Dirichlet distributions which, by better modeling word burstiness, provides a more realistic model of empirical observations on real document collections than the usually used Multinomials.
Cascaded RLS-LMS Prediction in MPEG-4 Lossless Audio Coding

This paper describes the cascaded recursive least square-least mean square (RLS-LMS) prediction, which is part of the recently published MPEG-4 Audio Lossless Coding international standard. The predictor consists of cascaded stages of simple linear predictors, with the prediction error at the output of one stage passed to the next stage as the input signal. A linear combiner adds up the intermediate estimates at the output of each prediction stage to give a final estimate of the RLS-LMS predictor. In the RLS-LMS predictor, the first prediction stage is a simple first-order predictor with a fixed coefficient value 1. The second prediction stage uses the recursive least square algorithm to adaptively update the predictor coefficients. The subsequent prediction stages use the normalized least mean square algorithm to update the predictor coefficients. The coefficients of the linear combiner are then updated using the sign-sign least mean square algorithm. For stereo audio signals, the RLS-LMS predictor uses both intrachannel prediction and interchannel prediction, which results in a 3% improvement in compression ratio over using only the intrachannel prediction. Through extensive tests, the MPEG-4 Audio Lossless coder using the RLS-LMS predictor has demonstrated a compression ratio that is on par with the best lossless audio coders in the field. In this paper, the structure of the RLS-LMS predictor is described in detail, and the optimal predictor configuration is studied through various experiments.
Effects of structural fluctuations on the photonic bandgap during fabrication of a photonic crystal: a study of a photonic crystal with a finite number of periods

We study theoretically the effects of structural fluctuations on the photonic bandgap during fabrication for the case of a photonic crystal with a finite number of periods. We use the transfer-matrix method to calculate the transmission spectra of the photonic crystals. The results of our calculations show that, even with a misalignment irregularity of 18%, the bandgap remains as large as 10%.
Limits of compound and thinned point processes

Let η =Σ j δτj be a point process on some space S and let β,β 1,β 2, … be identically distributed non-negative random variables which are mutually independent and independent of η. We can then form the compound point process ξ = Σ j β j δτj which is a random measure on S. The purpose of this paper is to study the limiting behaviour of ξ as . In the particular case when β takes the values 1 and 0 with probabilities p and 1 –p respectively, ξ becomes a p-thinning of η and our theorems contain some classical results by Rényi and others on the thinnings of a fixed process, as well as a characterization by Mecke of the class of subordinated Poisson processes.
A FINITE ELEMENT ANALYSIS OF THE STEADY LAMINAR ENTRANCE FLOW IN A 90" CURVED TUBE

SUMMARY A standard Galerkin finite element penalty function method is used to approximate the solution of the threedimensional Navier-Stokes equations for steady incompressible Newtonian entrance flow in a 90" curved tube (curvature ratio 6 = 1/6) for a triple of Dean numbers (K = 41,122 and 204). The computational results for the intermediate Dean number (K = 122) are compared with the results of laser-Doppler velocity measurements in an equivalent experimental model. For both the axial and secondary velocity components, fair agreement between the computational and experimental results is found.
Giant Elliptical Galaxies: Globular Clusters and UCDs

Abstract Explorations of the globular cluster populations in many nearby galaxies are revealing increasing connections to other dense stellar systems such as UCDs, DGTOs, and nuclear star clusters in dwarf galaxies. The nearest giant elliptical, NGC 5128, is now giving us a much-improved delineation of the GC Fundamental Plane of structural parameters, and indicates as well that the known correlation between GC scale size and metallicity is likely to be at least partly a projection effect coupled with the different spatial distributions of the metal-poor and metal-rich clusters. New photometry of the huge cluster populations around the giant Brightest Cluster Ellipticals, which allows us to study samples of many thousands of GCs at once, are now beginning to turn up surprising examples of “sequences” of high-mass GCs leading up to the UCD regime. Lastly, new modelling of cluster formation through a specially tuned semi-analytic galaxy formation code strongly suggests that the mass-metallicity relation now known to affect the blue GC sequence can arise fairly naturally out of such models, if significant numbers of the massive GCs actually represent the remnant nuclei of stripped dwarf satellites.