Miracle-dz/UniFAR-FTUs huggingface dataset:
Randomized numerical linear algebra: Foundations and algorithms

This survey describes probabilistic algorithms for linear algebraic computations, such as factorizing matrices and solving linear systems. It focuses on techniques that have a proven track record for real-world problems. The paper treats both the theoretical foundations of the subject and practical computational issues. Topics include norm estimation, matrix approximation by sampling, structured and unstructured random embeddings, linear regression problems, low-rank approximation, subspace iteration and Krylov methods, error estimation and adaptivity, interpolatory and CUR factorizations, Nyström approximation of positive semidefinite matrices, single-view (‘streaming’) algorithms, full rank-revealing factorizations, solvers for linear systems, and approximation of kernel matrices that arise in machine learning and in scientific computing.
Determinants of smallholder farmers’ decisions on fertilizer use for cereal crops in the Ethiopian highlands

Abstract This study identified decision variables influencing fertilizer adoption and optimal fertilizer rates among smallholder farmers in the Ethiopian highlands. The fertilizer adoption and fertilizer use were examined in four regional states using a questionnaire survey, which was administered to 2880 farm households. A double hurdle model was used to analyze factors influencing the two independent decisions of adoption of fertilizers and use of fertilizers. The model estimates of the first hurdle revealed that the probability of fertilizer adoption increased by 1.2% as household education status improved, by 1.4% for an increased number of active family members, by 5.6% with improved access to credit, by 3.4% with cooperative membership, by 3.3% with an increase in farm size, by 4.6% when soil and water conservation practices are employed, and by 3.4% when agroecology of the farm is located in the medium to highland zone. Conversely, the probability of fertilizer adoption reduced by 0.9% for an increase in family size, 0.6% with 1 km distance from all-weather road, 1.6% for a kilometer further to farm plots, and 0.9% for an increase in number of parcels. The intensity of use of fertilizers was influenced by education status of the household head, family size, access to credit, membership to cooperatives, use of crop rotation, annual income, number of farm plots owned, use of soil and water conservation, and agroecology. Therefore, a concerted effort is needed to encourage fertilizer adoption and optimum fertilizer use intensity by improving households’ resource endowment, institutional capacity to deliver services, and infrastructure development.
Using NIR Spectroscopy to Quantify Binary Ranitidine Hydrochloride Polymorphic Mixtures

T he possibility of producing multiple crystallographic forms from the same compound (polymorphism) increases with the structural complexity of active pharmaceutical ingredients. Given that each polymorph is a patentable entity with potentially different therapeutic attributes (i.e. different solubilities, stabilities and bioavailabilities), drug polymorphism represents a significant interest to the pharmaceutical industry. The Food and drug Administration (FdA) requires that knowledge of crystallographic variations be provided during the development of new drugs. X-ray powder diffraction is the goldstandard technique for the identification of polymorphs with a powdered mixture; however, this technique is typically destructive. The attention of the pharmaceutical industry has consequently been redirected to the field of vibrational spectroscopy for fast, cheap, accurate methods of polymorph identification and quantification within raw active pharmaceutical ingredients and formulations. NIR spectroscopy is being routinely incorporated into the analytical protocol of many pharmaceutical companies as it allows for large throughput, a consequence of minimal sample preparation, and may be used to analyse both the chemical and physical properties of a sample. Ranitidine hydrochloride is an H2 antagonist commonly used in the treatment of duodenal-gastric ulceration (Figure 1). Ranitidine hydrochloride exists in two stable forms; forms I and II. These two polymorphic forms have been the source of litigation over patent infringement claims, during which the detection of one polymorph in the other was key evidence. This case, among others, highlighted the need for suitable methods of polymorph detection and quantification. Ranitidine hydrochloride has subsequently become a model compound for determining the quality of analytical methods for polymorph detection and quantification. The polymorphism observed in ranitidine hydrochloride is primarily a result of the nitroethenediamine moiety. In theory this moiety may exist in three forms: enamine, nitronic acid and imine, each of which may exist as E / Z isomers. It has been shown that form II of ranitidine hydrochloride is a 1 : 1 mixture of the nitronic isomer (E ) and the enamine isomer (Z ). The crystal structure of form I, to the authors’ knowledge, has yet to be obtained; however, it is predicted to have a more ordered structure than form II. Identification and quantification of ranitidine hydrochloride has been investigated using diffuse reflectance infrared Fourier transform spectroscopy (dRIFTS), Raman and XRPd.
Administrative Records Mask Racially Biased Policing

Researchers often lack the necessary data to credibly estimate racial discrimination in policing. In particular, police administrative records lack information on civilians police observe but do not investigate. In this article, we show that if police racially discriminate when choosing whom to investigate, analyses using administrative records to estimate racial discrimination in police behavior are statistically biased, and many quantities of interest are unidentified—even among investigated individuals—absent strong and untestable assumptions. Using principal stratification in a causal mediation framework, we derive the exact form of the statistical bias that results from traditional estimation. We develop a bias-correction procedure and nonparametric sharp bounds for race effects, replicate published findings, and show the traditional estimator can severely underestimate levels of racially biased policing or mask discrimination entirely. We conclude by outlining a general and feasible design for future studies that is robust to this inferential snare.
Calculation of net emission coefficient in N2, SF6 and SF6-N2 arc plasmas

The net emission coefficient of SF6-N2 mixtures was calculated for temperatures between 8000 and 24000 K and pressures between 1 and 8 bar. The calculation of the radiative transfer of the lines required a study of line broadening and was performed assuming that line overlapping had a negligible influence. The results show that the resonance lines, although they are strongly absorbed, make up a large part of the net radiation-about as much as the continuum. Also, the nitrogen lines are more strongly absorbed than the lines of sulphur or fluorine. At low temperatures the radiation of SF6 is stronger than that of nitrogen. When T>12000 K the net radiation of the mixture is not proportional to the net radiations of the gases owing to variations in emissivity and line broadening with temperature and composition of the mixture.
Onset of fast magnetic reconnection and particle energization in laboratory and space plasmas

The onset of magnetic reconnection in space, astrophysical and laboratory plasmas is reviewed discussing results from theory, numerical simulations and observations. After a brief introduction on magnetic reconnection and approach to the question of onset, we first discuss recent theoretical models and numerical simulations, followed by observations of reconnection and its effects in space and astrophysical plasmas from satellites and ground-based detectors, as well as measurements of reconnection in laboratory plasma experiments. Mechanisms allowing reconnection spanning from collisional resistivity to kinetic effects as well as partial ionization are described, providing a description valid over a wide range of plasma parameters, and therefore applicable in principle to many different astrophysical and laboratory environments. Finally, we summarize the implications of reconnection onset physics for plasma dynamics throughout the Universe and illustrate how capturing the dynamics correctly is important to understanding particle acceleration. The goal of this review is to give a view on the present status of this topic and future interesting investigations, offering a unified approach.
Imaging of Molecular Coating on Nanoparticle Surface Using AFM Ringing Mode

The molecular coating of nanoparticles is important for particle functionalization. Direct imaging of the molecular coating on the nanoparticle’s surface with a sufficiently high lateral resolution is important though challenging. Recently introduced Ringing mode of atomic force microscopy (AFM) allows for simultaneous imaging of several maps of physical properties of a sample surface [1, 2], including imaging the height of the molecular coat. To the best of our knowledge, there is no other technique capable of measuring the presence of a thin layer of organic molecules on organic nanoparticles. The rival NIR AFM technique allows measuring of the presence of an organic layer on a nanoparticle core which has a substantially different coefficient of thermal expansion [3]. The lateral resolution of the coating reported in the literature is not well defined though but could be estimated in the range of 10 nm. Here we demonstrate that Ringing mode allows imaging of PEG on mesoporous silica with the lateral resolution down to ~1 nm. Furthermore, PEG coating on cellulose acetate particles can also be imaged in Ringing mode (though it is hard to estimate the resolution because of a rather smooth coating of cellulose acetate particles).
Catalytic Pyrolysis of Alga Saccharina japonica Using Co/γ-Al2O3 and Ni/γ-Al2O3 Catalyst

The catalytic pyrolysis of Saccharina japonica was investigated over Co and Ni catalyst supported on porous γ-Al2O3 in a tubing reactor. Both catalysts were found to exhibit a significant effect on the yield of bio-oil. The bio-oil derived from the pyrolysis consists primarily of dianhydromannitol and other compounds that can be an important source of liquid fuel. In the presence of 5 wt% Co/γ-Al2O3 catalyst with 2 wt% catalyst loading, the yield of the bio-oil from pyrolysis of S. japonica was enhanced remarkably to 40.7 wt% at a relatively low reaction temperature of 380°C within a short period of time (5 min).
[Regular Paper] Prediction of the Viscosity of Heavy Petroleum Fractions and Crude Oils by Neural Networks

In this work, the prediction of heavy petroleum fractions was significantly improved by using a backpropagation neural network model. It was found that scaling the data, fed to the neural net, improved the convergence of the estimated parameter (viscosity) in reasonable time with acceptable accuracy. An absolute error of 3.4% was achieved which is found to be better than those by other conventional methods.
Electrodermal activity

Electrodermal activity (EDA) was first observed in the 19th century although the term EDA was introduced as a common term for electrical phenomenon of the skin approximately 50 years ago (1). Since then, EDA has become a widely used scientific method in neuropsychiatry research. More recently, advances in amplifier instrumentation and a better understanding of the underlying principles of EDA have seen its use in clinical disciplines. However, by far, the greatest application of EDAhas been in the field of psychophysiology and the detection of deception (2–4). The majority of the work arising from psychophysiology studies have focused on EDA concomitants, which appear during stimulation and the processing of information by the brain. Of particular interest is the relationship between EDA and subtle physiological brain processes. Changes in EDA can occur as a result of a variety of sensory and psychological stimuli and typically are described in terms of an immediate phasic change often termed the skin conductance response (SCR).
Über neue Reaktionen von Sulfamiden

Verbindungen, welche Sulfamidgruppen tragen, reagieren in Form ihrer Alkalisalze leicht in wasriger Losung mit Isocyanaten, Senfolen und Diketen. Es werden dabei Sulfoharnstoffe, Sulfothioharnstoffe oder Acetoacetylsulfamide erhalten. Diese Reaktionen werden bei den Sulfamiden organischer Sulfonsauren, bei Sulfurylamid und einigen seiner Derivate durchgefuhrt.
Relationships between particle‐size distribution and organic carbon in French arable topsoils

A database including results from 102 000 soil analyses was built for arable topsoil in France. We show a strong effect of soil particle‐size distribution on present organic carbon (OC) stocks in these soils. By using the upper decile values by textural classes as a proxy of the maximal carbon storage potential, we show that it might be more efficient to encourage practices favouring carbon accumulation in soils already having high OC stocks than to try to increase OC stocks in soils where present stocks are low.
Davidson-type corrections for quasidegenerate states

Two new extensions of Davidson-type size-consistency collections to the case of quasidegenerate states are presented and applied to a simple model system in which the degree of quasidegeneracy can be continuously varied. The eight-electron model studied is a minimum basis set model involving eight hydrogen atoms in various spatial arrangements. The results are compared with the full CI energies as well as with those obtained with the CI-D, MRCI-D, coupled-pair, and linear coupled-pair methods. Two extensions of the Davidson correction recently devised by Paldus are also employed. The results indicate that all the Davidson-type corrections yield reliable correlation energies in the case of strong quasidegeneracies.
Spreading and Instabilities Induced by a Solutal Marangoni Effect

We study the spreading of liquid films driven by surface tension gradients induced by evaporation from a two-component mixture. The films climb from a macroscopic reservoir on a plane tilted surface and their length L is found to depend linearly on the square root of time t: L(t) = (Dt)0.5. We develop a semiquantitative analysis that shows which parameters control the value of D for ideal mixtures and for nonideal ones. We report also experimental results about the time evolution and the spatiotemporal behavior of the interfacial instability that develops at the meniscus between the reservoir and the film. Results agree well with previous experimental and theoretical studies.
Solvent dependence of the first hyperpolarizability of p-nitroanilines: Differences between nonspecific dipole–dipole interactions and solute–solvent H-bonds

In this paper, the influence of solvents on the first hyperpolarizability β of nonlinear optical (NLO) molecules is studied at 25 °C for solutions of p-nitroaniline and N,N-dimethyl paranitroaniline in some 50 solvents belonging to different classes. The hyperpolarizabilities deduced from measured hyper-Rayleigh scattering are the relative ones with as reference that of paranitroaniline in 1,4-dioxane. Taking for the latter the literature value of 16.9 10−30 esu, the β values vary from 14.4 to 29.9 10−30 esu for paranitroaniline and from 28.7 to 46.2 10−30 esu for N,N-dimethyl paranitroaniline. A selection of the solvents is made on the basis of the fraction of the time γ0 during which the NLO molecule is not involved in H-bonding with the solvent molecules. γ0 can be determined from the solubility in the given solvent. The formation of specific solute–solvent interactions as H-bonds always increases the hyperpolarizability β. In the absence of such interactions, the hyperpolarizability increases with the.
A double many‐body expansion of the two lowest‐energy potential surfaces and nonadiabatic coupling for H3

We present a consistent analytic representation of the two lowest potential energy surfaces for H3 and their nonadiabatic coupling. The surfaces are fits to ab initio calculations published previously by Liu and Siegbahn and also to new ab initio calculations reported here. The analytic representations are especially designed to be valid in the vicinity of the conical intersection of the two lowest surfaces, at geometries important for the H+H2 reaction, and in the van der Waals regions.
Glycidyl methacrylate grafted natural rubber: Synthesis, characterization, and mechanical property

Glycidyl methacrylate (GMA) was grafted onto natural rubber (NR) using emulsion polymerization method. The structures of copolymers were character- ized by 1 H nuclear magnetic resonance ( 1 H-NMR), solid state 13 C-NMR spectroscopy, and Fourier transform infrared spectrometer (FTIR). The %grafting obtained from the gravimetric method and the absorbance ratio were compared. Effects of reaction temperature, GMA content, and reaction time on %grafting, grafting effi- ciency, and %conversion of GMA monomer were deter- mined. Effect of %grafting on mechanical properties of the graft copolymer was studied. Experimental result showed that the appropriate reaction time was 8 h at a reaction temperature of 30 � C. Moreover, tensile strength and modulus of the graft copolymer increased with increasing %grafting. However, elongation at break of the graft copolymer decreased with increasing %graft- ing. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 3152-3159, 2011
Ion mobilities and transport cross sections of daughter negative ions in N2O and N2O–N2 mixtures

A pulsed Townsend apparatus is used to measure the mobility of a single negative ion species in N2O and N2O–N2 gas mixtures. The range of the density-normalized electric field, E/N, is 6.5–100 Td (1 Townsend = 10−17 V cm2) over the pressure range 10–250 Torr and temperature range 295–300 K. Based on previous work it is shown that the most likely drifting ion is . A reaction scheme involving ion conversion and electron detachment is presented, ending with the formation of a stable ion. The momentum transfer integral cross section for in pure N2O and N2 gases is derived from the above measurements. The unfolded cross sections are used as an initial guess and then further improved by ensuring good agreement between Monte Carlo calculated mobilities and the experimental results for the N2O–N2 mixture.
Auger Electron Spectroscopy (AES): A Versatile Microanalysis Technique in the Analyst's Toolbox

In order to determine the usefulness of an analytical technique and to differentiate it from other technique options for a given application, several criteria are important. These criteria include spatial resolution (lateral vs. depth; imaging vs. elemental composition), sampling depth, detection limits and quantifiability of the data. A graphical comparison of many of the techniques that are at the analyst’s disposal are shown in Figure 1. The role of Auger in this context will be discussed in detail.
Computer simulations of human interferon gamma mutated forms

In the general framework of the computer‐aided drug design, the method of molecular‐dynamics simulations is applied for investigation of the human interferon‐gamma (hIFN‐γ) binding to its two known ligands (its extracellular receptor and the heparin‐derived oligosaccharides). A study of 100 mutated hIFN‐γ forms is presented, the mutations encompassing residues 86–88. The structural changes are investigated by comparing the lengths of the α‐helices, in which these residues are included, in the native hIFN‐γ molecule and in the mutated forms. The most intriguing cases are examined in detail.
Tröger's Base Derivatives—New Life for Old Compounds

Synthetic Tröger's base derivatives are reviewed, including their properties and applications. The rigid V-shaped Tröger's base framework and its inherent chirality have promoted the preparation of diverse receptor systems. Heterocyclic Tröger's base derivatives exhibit affinity for DNA. Metal complexes of Tröger's base are used as catalysts. New applications continue to emerge as synthetic methods are developed.
Redescription and molecular characterization of Crenidens macracanthus Günther, 1874 (Pisces: Sparidae), and first record of C. indicus Day, 1873 in the eastern Indian Ocean

Abstract Crenidens macracanthus was originally described in 1874 based on a single specimen collected from Chennai (Madras), south-east coast of India. In 1875, the species was synonymized with C. indicus without citing any valid reason. Since then, no taxonomic studies have been attempted for the genus Crenidens, except in 2013 the species was resurrected from synonymy and redescribed as a valid species based on the holotype and non-type specimen. In view of the fact that C. macracanthus is a poorly known species, it is redescribed based on examination of 30 additional specimens of 105.8–162.2 mm SL, collected from Puri, Odisha, north-east coast of India (Bay of Bengal) from 2017–2019, using morphological and molecular examinations. Our study provides a detailed morphological description, first colour photographs and phylogenetic analysis using COI barcodes of the species. The study has expanded the range in several morpho-meristic characters in comparison with the type and non-type specimens described earlier. The species in fresh condition can be easily distinguished from its two congeners (C. crenidens and C. indicus) by the yellowish tip of the lower caudal-fin lobe. Our study has also extended the distribution range of C. indicus (previously known only from the north-eastern Arabian Sea) to the eastern Indian Ocean, based on examination of a preserved specimen collected from Tuticorin, Tamil Nadu.
Impact of the Alkyl Side Chains on the Optoelectronic Properties of a Series of Photovoltaic Low-Band-Gap Copolymers

The design of novel low-band-gap conjugated polymers with appropriate frontier orbital energy levels and good charge transport is needed to improve the conversion efficiency of organic photovoltaic devices. In this article, we describe the synthesis and structure−property relationships of a series of photovoltaic copolymers with a common conjugated backbone and differing solubilizing side chains. The copolymer optoelectronic properties and the related photovoltaic device performances are reported. Our results clearly show that the side chains have a major impact on the material and device properties. The electronic band gap can be varied by more than 0.3 eV, the charge mobilities by orders of magnitude, and the optimized fullerene content of photovoltaic devices by a factor of 4 by barely changing the side-chain positioning and/or by switching from linear to branched alkyl chains. A power conversion efficiency of 2.7% could be achieved with devices using the most promising polymer.
A theoretical study of N–H ··· π H-bond interaction of pyrrole: from clusters to the liquid

The N–H ··· π H-bond interactions of clusters and liquid formed by pyrrole molecules were investigated by Quantum Mechanics (QM) and classical Molecular Dynamics (MD), respectively. Based on the optimized geometry at the B97-D/aug-cc-pVTZ level of theory including dispersion correction, the nature and the origin of N–H ··· π H-bond interactions were unveiled by atoms in molecules (AIM), natural bond orbital (NBO), and energy decomposition analysis (EDA). Among them, the AIM analysis gives evidence to the presence of N–H ··· π H-bond interactions, the NBO examination reveals that π → σ* donor-acceptor orbital interaction is of great importance. EDA study indicates that N–H ··· π interactions are governed by the electrostatic and dispersion term. Meanwhile, MD simulation with OPLS-AA (optimized potentials for liquid simulations all-atom) was applied to study the pure liquid pyrrole at different temperature. The results confirm the existence of the N–H ··· π H-bond in the pure liquid pyrrole, and further characterized the structures of this H-bond which is somewhat different to the clusters.