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The advent of chatbots raises the possibility of a paradigm shift across society including the most technical of fields with regard to access to information, generation of knowledge, and dissemination of education and training. Photochemistry is a scientific endeavor with roots in chemistry and physics and branches that encompass diverse disciplines ranging from astronomy to zoology. Here, five chatbots have each been challenged with 13 photochemically relevant queries. The chatbots included ChatGPT 3.5, ChatGPT 4.0, Copilot, Gemini Advanced, and Meta AI. The queries encompassed fundamental concepts (e.g., “Why is the fluorescence spectrum typically the mirror image of the absorption spectrum?”), practical matters (e.g., “What is the inner filter effect and how to avoid it?”), philosophical matters (“Please create the most important photochemistry questions.”), and specific molecular features (e.g., “Why are azo dyes non‐fluorescent?”). The chatbots were moderately effective in answering queries concerning fundamental concepts in photochemistry but were glaringly deficient in specialized queries for dyes and fluorophores. In some instances, a correct response was embedded in verbose scientific nonsense whereas in others the entire response, while grammatically correct, was utterly meaningless. The unreliable accuracy makes present chatbots poorly suited for unaided educational purposes and highlights the importance of domain experts. [ABSTRACT FROM AUTHOR]

The paper examines afterglow spectra of chlorine–xenon mixtures excited by XeCl laser pulses (308 nm). The dependence of the spectra on the composition and pressure of the mixtures is shown. The mixtures are compared with the total luminescence spectra measured under similar conditions. The time characteristics of excitation and luminescence pulses are presented. [ABSTRACT FROM AUTHOR]

Denote by H the set of all quaternions. We are interested in the group U (1 , 1 ; H) , which is a subgroup of 2 × 2 quaternionic matrix group and is sometimes called Sp(1, 1). As well known, U (1 , 1 ; H) corresponds to the quaternionic Möbius transformations on the unit ball in H . In this article, some similarity invariants on U (1 , 1 ; H) are discussed. Our main result shows that each matrix T ∈ U (1 , 1 ; H) , which corresponds to an elliptic quaternionic Möbius transformation g T (z) , could be U (1 , 1 ; H) -similar to a diagonal matrix. Moreover, one can see that each elliptic quaternionic Möbius transformation is quaternionic Möbius conjugate to a bi-rotation, where a bi-rotation means a map z → p · z · q - 1 for some p , q ∈ H with | p | = | q | = 1 . [ABSTRACT FROM AUTHOR]

In the present study, we have estimated the coda Q (QC) and the geometrical spreading factor (gamma) for the Saurashtra region that is located in the western part of the Deccan Volcanic Province, Gujarat, India. The waveform data from the seismic network operated by the Institute of Seismological Research, Gandhinagar, are used for the analysis. We have used records of a total of 221 local earthquakes with epicentral distances less than 70 km from the seismic stations. The moment magnitude range of the earthquakes is 2.5-5.3, and the depth range is 1-22 km. The QC has been estimated at five central frequencies (1.5, 3, 6, 12, and 20 Hz) using 20, 30, and 40 s window lengths for vertical, north-south, and east-west components, respectively. The obtained QC values show that the attenuation in the region has a strong dependence on frequency and points toward a heterogeneous medium. The geometrical spreading factors are also estimated for two cases, that is, with and without Q at the same central frequencies and window lengths. The average geometrical spreading factors with Q are 1.37, 1.48, 1.40, 1.08, and 1.04, at central frequencies 1.5, 3, 6, 12, and 20 Hz, respectively, whereas it is 1.59, 1.53, 1.47, 1.19, and 1.14, respectively, in the absence of Q. The estimated values also indicate that the medium is heterogeneous in the Saurashtra region. The estimated region-specific coda Q and the geometrical spreading factor may help in the modeling of strong ground motions and assessment of the seismic hazard for the Saurashtra region. [ABSTRACT FROM AUTHOR]

The unsteady pressure field over an axisymmetric backward-facing step was investigated experimentally at transonic freestream Mach numbers of 1.05, 1.2, and 1.4. The study was aimed at examining the influence of transonic freestream Mach numbers on the spatio-temporal character of the unsteady pressure field and on the dominant modes/mechanisms driving it. Surface flow visualization, schlieren, and unsteady pressure measurements were carried out as part of the experimental investigation. From oil flow visualization and schlieren, the reattachment region was identified, and consequently, the mean reattachment length was estimated. The mean reattachment length shows an increase with the increase in freestream Mach number. The coefficient of mean pressure along the rearbody imitates a classical backward-facing step flow profile and can be divided into three distinct regions. The peak values of the coefficient of mean pressure and the coefficient of root mean square of the fluctuation are seen to decrease with an increase in the freestream Mach number. Conventional spectral analysis reveals that as the freestream Mach number increases, the dominant peak in the spectra shifts to lower frequencies. From the spectra, three dominant fluid dynamic mechanisms depending on the freestream Mach number have been identified. Proper Orthogonal Decomposition (POD) analysis shows that 79–84 % of the total energy contribution comes from the first six modes. The temporal dynamics of the POD modes indicate three prominent mechanisms are responsible for the unsteady pressure field. Spectral analysis of POD modes indicates that the spectra are primarily driven by the first three POD modes for freestream Mach number of 1.05 and the first two modes for freestream Mach numbers of 1.2 and 1.4. Moreover, it reveals the presence of three dominant modes, and the freestream Mach number strongly dictates the dominant mode that is driving the pressure field. [ABSTRACT FROM AUTHOR]

The existence of a Fourier basis with frequencies in R d for the space of square integrable functions supported on a given parallelepiped in R d , has been well understood since the 1950s. In a companion paper, we derived necessary and sufficient conditions for a parallelepiped in R d to permit an orthogonal basis of exponentials with frequencies constrained to be a subset of a prescribed lattice in R d , a restriction relevant in many applications. In this paper, we investigate analogous conditions for parallelepipeds that permit a Riesz basis of exponentials with the same constraints on the frequencies. We provide a sufficient condition on the parallelepiped for the Riesz basis case which directly extends one of the necessary and sufficient conditions obtained in the orthogonal basis case. We also provide a sufficient condition which constrains the spectral norm of the matrix generating the parallelepiped, instead of constraining the structure of the matrix. [ABSTRACT FROM AUTHOR]

Let $\{b_n\}_{n=1}^{\infty }$ be a sequence of integers larger than 1. We will study the harmonic analysis of the equal-weighted Moran measures $\mu _{\{b_n\},\{{\mathcal D}_n\}}$ with ${\mathcal D}_n=\{0,1,2,\ldots ,q_n-1\}$ , where $q_n$ divides $b_n$ for all $n\geq 1.$ In this paper, we first characterize all the maximal orthogonal sets of $L^2(\mu _{\{b_n\},\{{\mathcal D}_n\}})$ via a tree mapping. By this characterization, we give some sufficient conditions for the maximal orthogonal set to be an orthonormal basis. [ABSTRACT FROM AUTHOR]

Abstract The utilization of visible-near infrared (Vis–NIR) spectroscopy presents a nondestructive, fast, reliable and cost-effective approach to predicting total nitrogen (TN) and organic carbon (OC) levels. This study employed a combination of Vis–NIR spectroscopy, partial least-squares regression (PLSR), and support vector machine (SVM) models to investigate the effects of mining on TN and OC stocks in both the topsoil (0–10 cm) and subsoil (10–40 cm). 105 soil samples were collected from agricultural areas near an iron mine, polluted, moderately-polluted, and non-polluted sites. Results indicated that soils at the non-polluted site had the highest of soil OC stocks (7.5 kg m–2) and total nitrogen (2.5 kg m–2), followed by the moderately-polluted site. Furthermore, it was observed that soils from the polluted site displayed the highest spectral reflectance. The spectral bands in the range of 500–700 nm showed the strongest correlation with soil organic carbon content. Notably, the SVM method utilizing Vis–NIR spectroscopy provided superior predictions for both subsoil and topsoil organic carbon and total nitrogen compared to the PLSR methods. Additionally, SVM demonstrated better performance in predicting topsoil soil organic carbon (R2 = 0.87, RMSE = 0.13%, and RPD = 2.8) and total nitrogen (R2 = 0.91, RMSE = 0.13%, and RPD = 2.4) compared to the subsoil, owing to the larger OM content in the topsoils.

Soil profile organic carbon (OC) and total nitrogen (TN) are influenced by topographic attributes, and land use. The visible and near-infrared (Vis-NIR) spectroscopy method can be used for the prediction of OC and TN because it is reliable, nondestructive, fast, and cost-effective. VIS-NIR soil spectral and environmental data were combined with the Partial least squares regression (PLSR) model to examine the effect of topography attributes and land use on topsoil and subsoil OC and TN stocks. After this, based on the soil depth, 114 soil samples were collected from 0 to 20 cm (topsoil) and 20–50 cm (subsoil) under three land uses, as well as OC and TN, along with several soil properties including soil particles (sand, silt, clay), pH, and bulk density in both topsoil and subsoil samples were measured. A DEM with a resolution of 30 m was used to derive the topography factors and remote sensing data was used to calculate the vegetation index. Soils (0–50 cm) under orchard land use had the highest stock of SOC (7.4 kg m−2) as well as TN (2.4 kg m−2). There was a significant increase in the organic matter stock of soils located on the south aspect (8.3 kg m−2) compared to soils located on other aspects, particularly on the north aspect (3.9% increase). Soils on the south aspect contain higher soil-water contents and lower temperatures, resulting in a decrease in the decomposition of soil organic matter. A strong positive correlation was demonstrated between topography wetness index (0.57–0.63) and topography TN stocks (0.54–0.66) as well as the highest loading score among terrain attributes, suggesting that topography is the primary factor controlling SOC stocks, particularly subsoil stocks. Additionally, we found that soils on the south-facing aspects (N aspects) had the highest spectra. Additionally, the PLSR, which showed an R2 of 0.82, a RMSE of 0.15 %, and a RPD of 0.39 indicated excellent prediction capabilities for the OC content. We concluded that the PLSR model coupled with Vis-NIR spectroscopy is able to predict topsoil and subsoil OC and N content under different aspect slopes.

In this paper, we introduce the notion of free non-Archimedean quasi-Banach spaces. We prove some results on non-Archimedean quasi-Banach spaces and we give some examples of such spaces. The uniform boundedness principle, the closed graph theorem, the Banach's open mapping theorem and the bounded inverse theorem for non-Archimedean quasi-Banach spaces are proved. Furthermore, we define the notions of closed linear operators, bounded below operators, invertible operators, -spectral operators, finite rank operators and completely continuous operators on non-Archimedean quasi-Banach spaces and we establish some results about them. The spectral theory of bounded linear operators is studied. Finally, the quasi-norm convergence, the quasi-pointwise convergence and the quasi -convergence are introduced and studied. Several examples are provided. [ABSTRACT FROM AUTHOR]

Abstract Cancer, a lethal ailment, possesses a multitude of therapeutic alternatives to combat its presence, metal complexes have emerged as significant classes of medicinal compounds, exhibiting considerable biological efficacy, especially as anticancer agents. The utilization of cis-platin in the treatment of various cancer types, including breast cancer, has served as inspiration to devise novel nanostructured metal complexes for breast cancer therapy. Notably, homo- and hetero-octahedral bimetallic complexes of an innovative multifunctional ether ligand (comprising Mn(II), Ni(II), Cu(II), Zn(II), Hg(II), and Ag(I) ions) have been synthesized. To ascertain their structural characteristics, elemental and spectral analyses, encompassing IR, UV–Vis, 1H-NMR, mass and electron spin resonance (ESR) spectra, magnetic moments, molar conductance, thermal analysis, and electron microscopy, were employed. The molar conductance of these complexes in DMF demonstrated a non-electrolytic nature. Nanostructured forms of the complexes were identified through electron microscopic data. At ambient temperature, the ESR spectra of the solid complexes exhibited anisotropic and isotropic variants, indicative of covalent bonding. The ligand and several of its metal complexes were subjected to cytotoxicity testing against breast cancer protein 3S7S and liver cancer protein 4OO6, with the Ag(I) complex (7) evincing the most potent effect, followed by the Cu(II) with ligand (complex (2)), Cis-platin, the ligand itself, and the Cu(II)/Zn(II) complex (8). Molecular docking data unveiled the inhibitory order of several complexes.

Let 풳 and 풴 be Banach spaces. When 풜 and ℬ are linear relations in 풳 and 풴, respectively, we denote by ℳ풞 the linear relation matrix acting on 풳×풴 of the form ℳ풞 = 풜풞0 ℬ , where 0 is the zero operator and 풞 is a bounded operator from 풴 to 풳. In this paper, we prove that if σ∗(.) denotes the Weyl spectrum, the Browder spectrum or the Drazin spectrum of a linear relation, then for every 풞∈ℒ(풴,풳), we have the equality σ∗(풜) ∪ σ∗(ℬ) = σ∗(ℳ풞) ∪풲 where 풲 a subset of σ∗(풜) ∩ σ∗(ℬ). Moreover, we explore how Weyl’s theorem and Browder’s theorem hold for linear relation matrices. [ABSTRACT FROM AUTHOR]

Cancer, a lethal ailment, possesses a multitude of therapeutic alternatives to combat its presence, metal complexes have emerged as significant classes of medicinal compounds, exhibiting considerable biological efficacy, especially as anticancer agents. The utilization of cis-platin in the treatment of various cancer types, including breast cancer, has served as inspiration to devise novel nanostructured metal complexes for breast cancer therapy. Notably, homo- and hetero-octahedral bimetallic complexes of an innovative multifunctional ether ligand (comprising Mn(II), Ni(II), Cu(II), Zn(II), Hg(II), and Ag(I) ions) have been synthesized. To ascertain their structural characteristics, elemental and spectral analyses, encompassing IR, UV–Vis, 1H-NMR, mass and electron spin resonance (ESR) spectra, magnetic moments, molar conductance, thermal analysis, and electron microscopy, were employed. The molar conductance of these complexes in DMF demonstrated a non-electrolytic nature. Nanostructured forms of the complexes were identified through electron microscopic data. At ambient temperature, the ESR spectra of the solid complexes exhibited anisotropic and isotropic variants, indicative of covalent bonding. The ligand and several of its metal complexes were subjected to cytotoxicity testing against breast cancer protein 3S7S and liver cancer protein 4OO6, with the Ag(I) complex (7) evincing the most potent effect, followed by the Cu(II) with ligand (complex (2)), Cis-platin, the ligand itself, and the Cu(II)/Zn(II) complex (8). Molecular docking data unveiled the inhibitory order of several complexes. [ABSTRACT FROM AUTHOR]

The present study is a theoretical investigation into the structural evolution, electronic properties, and photoelectron spectra of phosphorus-doped boron clusters PBn0/− (n = 3–17). The results of this study revealed that the lowest energy structures of PBn− (n = 3–17) clusters, except for PB17−, exhibit planar or quasi-planar structures. The lowest energy structures of PBn (n = 3–17), with the exceptions of PB7, PB9, and PB15, are planar or quasi-planar. The ground state of PB7 has an umbrella-shaped structure, with C6V symmetry. Interestingly, the neutral cluster PB15 has a half-sandwich-like structure, in which the P atom is attached to three B atoms at one end of the sandwich, exhibiting excellent relative and chemical stability due to its higher second-order energy difference and larger HOMO–LUMO energy gap of 4.31 eV. Subsequently, adaptive natural density partitioning (AdNDP) and electron localization function (ELF) analyses demonstrate the bonding characteristics of PB7 and PB15, providing support for the validity of their stability. The calculated photoelectron spectra show distinct characteristic peaks of PBn− (n = 3–17) clusters, thus providing theoretical evidence for the future identification of doped boron clusters. In summary, our work has significant implications for understanding the structural evolution of doped boron clusters PBn0/− (n = 3–17), motivating further experiments regarding doped boron clusters. [ABSTRACT FROM AUTHOR]

Pomegranate molasses is made from concentrated pomegranate juice with nothing added. Due to its nutritional value, limitation in production, and high production cost, this product may be adulterated by date syrup. This study was done to differentiate various types of pomegranate molasses and investigate the possibility of nonauthenticity detection in pomegranate molasses samples using the hyperspectral imaging (HSI) technique compared with physicochemical measurement analysis. The physicochemical properties (brix index, sucrose, acidity, ash content, pH, and formalin index) of 24 samples were measured as the reference analysis method, and it was found that the formalin index was a good factor for pomegranate molasses authenticity evaluation. Additionally, an HSI system (400–1000 nm) was used as a nondestructive and rapid screening method to capture spectral data of the samples. The evolutionary wavelength selection algorithm was applied to select effective wavelengths in sample clustering based on the obtained Davies–Bouldin index. Next, principal component analysis was used to visually interpret the spectral data of the sample when using the selected wavelengths and the whole spectra of the samples. Finally, an automatic clustering algorithm by the artificial bee colony as an unsupervised method was developed for the clustering of the authentic and nonauthentic samples. The method did not need descriptively labeled samples and obtained agreed satisfactorily with the degree of nonauthenticity in the samples. This study showed that the developed HSI technique coupled with an automatic clustering algorithm could detect date syrup nonauthenticity in pomegranate samples from the level of 5% adulteration. [ABSTRACT FROM AUTHOR]

For all the nuclear reactor systems, quantitative assessment of the accident management (AM) effects against long-term external hazards became one of the essential issues after the lesson learned from the Fukushima Daiichi Nuclear Power Plant accident. However, the influence from the safety systems' stochastic and dynamic shifting between multiple working states, which is related to the interaction with the adjacent components/systems in general, has not been accounted for yet. Therefore, this research aims to develop a dynamic probability risk assessment tool considering repairable multi-component interdependency for investigating the AM influences on the multi-state safety systems under long-term external hazards. Based on the newly proposed methodology in this research via integrating the Petri net (PN) model with the continuous Markov chain Monte Carlo (CMMC) method, a framework applying PN-CMMC methodology to a severe accident analysis code, SPECTRA, had been originally constructed. Different AM influences on the multi-state decay heat removal systems against long-term volcanic ashfall were also quantitatively confirmed, indicating that halving the repairing time is more influential in suppressing the core damage frequency than doubling the number of adjacent electricity support systems. Therefore, the PN-CMMC-SPECTRA framework can further assess the uncharted dynamic multi-state concerns, leading to a safer AM strategy. [ABSTRACT FROM AUTHOR]

AbstractIn recent years, there has been renewed interest in molten salt reactors (MSRs) for their potential advantages compared to reactors that rely on solid fuel. In response to such interest, many methods and codes have been developed to capture the unique features of MSRs. Among them, SPECTRA and SAM are two system analysis codes that have been enhanced to include MSR-specific modeling capabilities, including delayed neutron precursor drift and modified point kinetics equations.This paper discusses the efforts taken to verify and validate these features. A standard MSR system test problem was developed to verify and demonstrate the capability of SPECTRA and SAM on the MSR transient simulation. Sixteen transients were simulated. The results obtained from SPECTRA and SAM show good agreement. The Molten Salt Reactor Experiment transient experiments were reviewed and selected to validate the SPECTRA and SAM codes. The experiments included pump startup and coastdown tests at zero power, reactivity insertion tests at different power levels, frequency tests, and a natural convection test. The simulation results from SPECTRA and SAM show good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

In this paper we investigate the harmonic analysis of infinite convolutions generated by admissible pairs on Euclidean space R n . Our main results give several sufficient conditions so that the infinite convolution μ to be a spectral measure, that is, its Hilbert space L 2 (μ) admits a family of orthonormal basis of exponentials. As a concrete application, we give a complete characterization on the spectral property for certain infinite convolution on the plane R 2 in terms of admissible pairs. [ABSTRACT FROM AUTHOR]

Speckle patterns generated by the intermodal interference of multimode fibers enable accurate broadband wavelength measurements. However, the measurement speed is limited by the frame rate of the camera that captures the patterns. We propose a compact and cost-effective ultrafast wavemeter based on multimode and multicore fibers, which employs spectral–spatial–temporal mapping. The speckle patterns generated by multimode fibers enable spectral-to-spatial mapping, which is then sampled by a multicore fiber into a pulse sequence to implement spatial-to-temporal mapping. A high-speed single-pixel photodetector is employed to capture the pulse sequence, which is analysed using a multilayer perceptron to estimate the wavelength. The feasibility of the proposed wavelength estimation method is experimentally verified, achieving a measurement rate of 100 MHz with a resolution of 2.7 pm in a 1 nm operation bandwidth.

The main purpose of this paper is to investigate the converse problems of some well-known results related to the generalized Drazin (g-Drazin for short) inverse in Banach algebras. Let A be a Banach algebra and a , b ∈ A . First, we give the relationship between the Drazin (g-Drazin, group) invertibility of a, b and that of the sum a + b under certain conditions. Then, for a given polynomial f (x) ∈ C [ x ] , the g-Drazin invertibility of f(a), f (a d) , f(ab), f (1 - a b) and f (a + b) are investigated. [ABSTRACT FROM AUTHOR]

Let ∑ i = 1 ∞ A i A i ∗ and ∑ i = 1 ∞ A i ∗ A i converge in the strong operator topology. We study the map Φ A defined on the Banach space of all bounded linear operators B (H) by Φ A (X) = ∑ i = 1 ∞ A i X A i ∗ and its restriction Φ A | K (H) to the Banach space of all compact operators K (H). We first consider the relationship between the boundary eigenvalues of Φ A | K (H) and its fixed points. Also, we show that the spectra of Φ A and Φ A | K (H) are the same sets. In particular, the spectra of two completely positive maps involving the unilateral shift are described. [ABSTRACT FROM AUTHOR]

Lichens are combinations of two symbiotic organisms, a green alga or cyanobacterium and a fungus. They grow in nearly all terrestrial ecosystems and survive in habitats, which are very dry or cold, or too poor in nutrients to maintain vegetation growth. Because lichens grow on visible surfaces and exhibit spectral properties, which are clearly different from, for example, vegetation, it is possible to distinguish them in remote sensing data. In this first systematic review article on remote sensing of lichens, we analyze and summarize which lichen species or genera, and in which habitats and geographical regions, have been remotely sensed, and which remote sensing or spectroscopic technologies have been used. We found that laboratory or in situ measured spectra of over 70 lichen species have been reported to date. We show that studies on remote sensing of lichens fall under seven broad themes: (1) collection of lichen spectra for quantification of lichen species or characteristics, (2) pollution monitoring with lichens as ecological indicators, (3) geological and lithological mapping, (4) desert and dryland monitoring, (5) animal habitat monitoring, (6) land cover or vegetation mapping, and (7) surface energy budget modeling. [ABSTRACT FROM AUTHOR]

Spectra of rare gas (Rg) – D2O dimers (Rg = Ar, Kr, Xe) are studied in the region of the D2O ν3 asymmetric stretch (≈2800 cm−1), using a rapid-scan tunable infrared optical parametric oscillator source to probe a pulsed supersonic slit jet expansion. Three bands are observed in each case, labelled according to the D2O rotational transition with which they correlate as: Σ(101) ← Σ(000), Π(101) ← Σ(000), and Σ(000) ← Σ(101). The Ar-D2O bands exhibit various perturbations and line broadening effects. For Kr-D2O, the Π(101) ← Σ(000) and Σ(000) ← Σ(101) bands are simple and relatively unperturbed with almost no resolved Kr isotope structure, while the Σ(101) ← Σ(000) band is highly perturbed and shows large isotope splittings. This latter perturbation is analyzed in detail with good results. For Xe-D2O, the experimental spectra are unfortunately weaker. Analysis of the Π(101) ← Σ(000) and Σ(000) ← Σ(101) bands is again relatively straightforward, but the Σ(101) ← Σ(000) band is even more perturbed than for Kr-D2O and its analysis proves impossible. Line broadening (for Ar-D2O) and vibrational frequency shift effects are described. [ABSTRACT FROM AUTHOR]

Enhanced optical and infrared activity of subwavelength metal nanoparticles is key to their use in optoelectronics, spectroscopy, and sensing. The present work compared spectra of nanosphere dimers merged by centrifuging gold nanospheres with corresponding simulated nanoscale dimers. Geometric features of the nanosphere dimers were related to corresponding optical and near-infrared activity through simulation. Differences in optical and infrared activity of the nanosphere dimers were largely attributable to changes in the radius of the nanosphere and the radius of the conductive junction between merged nanospheres. The features observed in the experimental spectra were attributed to a select number of dimers exhibiting predominantly optical and infrared activity, consistent with observations made in the corresponding transmission electron microscope image. The preparation and simulation methods in the present work appear useful to guide design, fabrication, and implementation of sustainably-synthesized nanosphere dimers with desired optical features for optoelectronic, spectroscopic, and sensing applications.

We studied the regional seismic hazard of the state of Sinaloa with emphasis on Los Mochis city, located in the municipality of Ahome, Sinaloa. Acceleration in rock was determined for different return periods (Tr = 475, 975, and 2475 years). We compared these results with the spectral accelerations proposed in the buildings seismic design Handbook by Earthquake of the Federal Electricity Commission (commonly applied in Mexico when absence of local regulations). It was observed that the seismic hazard was very sensitive to changes in the geometry of the source that contributes most to seismic hazard of the city. Particularly, PGA values were compared for 475 years, and it was observed that the increase in the PGA value due to that adjustment was approximately 35%. Additionally we performed a zonation study in the city, based on microtremors using single-station by applying horizontal-to-vertical spectral ratios (HVSR) analysis to 32 sites within the city. Results show low variations with higher values of natural period of resonance (To) in the southwest of the city. We explore a possible response for the entire valley by calculating a seismic hazard curve in terms of amplification factors.

Agar-carboxymethylcellulose-silver nanoparticle (AG-CMC-AgNP) nanocomposite was fabricated from modification of cellulose (extracted from Egyptian macroalga Ulva fasciata) to carboxymethylcellulose (CMC), with silver nanoparticles, and agar (AG; extracted from Gelidium crinale). The characteristics of AG-CMC-AgNP were enlightened by using Fourier transform infrared (FTIR), UV–visible (UV–vis), X-ray powder diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM–EDX), thermogravimetric analysis (TGA), and the zero-point charge of pH (pHZPC) measurements. Batch sorption investigations were carried out to determine the optimum experimental conditions (pH, contact time, temperature, amount of sorbent and initial methylene blue (MB) dye concentration). The maximal adsorption capacity of AG-CMC-AgNP (50 mg) was found to be 66.68 mg g−1, forming a monolayer of MB at 25 °C, for 150 min at pH 5.5. The adsorption of MB onto AG-CMC-AgNP strongly obeyed the Langmuir isotherm and agreed well with the pseudo-second-order reaction (PSORE) kinetic model. The thermodynamic parameters indicated a feasible, spontaneous, endothermic, and more randomness state existing at the solid–liquid interfaces. The biosorbent can be reused, but with a decrease in the amount of adsorbed MB dye after the fifth cycle. The interaction of MB adsorbed onto AG-CMC-AgNP was discussed using spectroscopic, morphological, and TGA measurements. [ABSTRACT FROM AUTHOR]

This paper studies the conductivity and chemiresistive H2S gas sensitivity of graphene (75wt%)-Cu(25wt%) composite thin film, using self-made chamber and common laboratory apparatus. The method adopted involves mixture of 2 drops of ethanol with the synthesized composite and prepared on a glass substrate by tape casting method. Two small copper metal sheets were used as electrodes for clipping of crocodile which were also connected to digital meter for resistance readings and its changes. The X-ray Diffraction (XRD) shows that annealing temperature reduced the crystallite sizes. The Fourier Transform Infrared Radiation (FTIR) spectra show the functional groups present to be transition metal carbonyls or aromatic combination bands, terminal alkyne (monosubstituted), isothiocyanate and that between 2300 and 2400 cm-1 indicates N=C=S functional group and evidence of CO2 interaction with external surface of the material or intercalating in the interlayer of the host material Also, increase in the conductivity was observed due to decrease in resistivity. The response/sensitivity peak of the sensor to hydrogen sulfide was seen to rise proportionally as temperature rose with percentage 3.97% for as grown, annealed at 200°C is at 12.98% while the annealed at 400°C is at 27.34%. [ABSTRACT FROM AUTHOR]

The Anomalous Cosmic Ray (ACR) spectra and intensity in the middle atmosphere are determined using the CORSIMA (COsmic Ray Spectra and Intensity in Middle Atmosphere) model. ACR spectra are presented for various atmospheric altitudes within the range of 40-50 km, with the lower boundary of the ionosphere at approximately 50 km. Experimental satellite measurements are utilized for the main ACR constituents Helium and Oxygen nuclei. It is found that the influence of ACRs extends to the polar cap regions above 65°-70° geomagnetic latitude, and certain ACR ionization rate values in these regions are comparable to Galactic Cosmic Ray (GCR) ionization rates. Our studies also consider Multiply Charged Anomalous Cosmic Rays (MCACRs), which exhibit similar differential spectra to the singly ionized ACR component4. [ABSTRACT FROM AUTHOR]

New Eu(III) and Tb(III) hybrid materials based on N-((1-methyl-3-(pyridin-2-yl)-1H-1,2,4-triazol-5-yl)methyl)methacrylamide were synthesized and characterized as potential fluorescent emitters. Complexes of Eu(III) and Tb(III) demonstrate red and green luminescence in the visible region, respectively. The intense broad bands in the region of 270-290nm are related to electronic transitions within pyridine-triazole-containing fragment coordinated to Ln(III) ion. [ABSTRACT FROM AUTHOR]

Introduction: Ultraluminous X-ray sources (ULXs) represent an extreme class of accreting compact objects: from the identification of some of the accretors as neutron stars to the detection of powerful winds travelling at 0.1-0.2 c, the increasing evidence points towards ULXs harbouring stellar-mass compact objects undergoing highly super-Eddington accretion. Measuring their intrinsic properties, such as the accretion rate onto the compact object, the outflow rate, the masses of accretor/companion-hence their progenitors, lifetimes, and future evolution-is challenging due to ULXs being mostly extragalactic and in crowded fields. Yet ULXs represent our best opportunity to understand super-Eddington accretion physics and the paths through binary evolution to eventual double compact object binaries and gravitational-wave sources. Methods: Through a combination of end-to-end and single-source simulations, we investigate the ability of HEX-P to study ULXs in the context of their host galaxies and compare it to XMM-Newton and NuSTAR, the current instruments with the most similar capabilities. Results: HEX-P's higher sensitivity, which is driven by its narrow point-spread function and low background, allows it to detect pulsations and broad spectral features from ULXs better than XMM-Newton and NuSTAR. Discussion: We describe the value of HEX-P in understanding ULXs and their associated key physics, through a combination of broadband sensitivity, timing resolution, and angular resolution, which make the mission ideal for pulsation detection and low-background, broadband spectral studies. [ABSTRACT FROM AUTHOR]

The intensively developed densely populated parts of the Baikal–Mongolian region (BMR) within the Selenga River basin and the southwestern part of the Baikal seismic zone have been selected for research. Geomorphologically, the territory is located within the Selenga Dauria, which merges with the mountain ranges of Mongolia. Earthquakes constantly occur here, and their strength varies widely, sometimes reaching catastrophic values. The high seismic potential of the region is due to the presence at a relatively short distance of seismically active zones in the north (Lake Baikal) and in the south (Mongolia) and the presence of earthquake epicenters with an energy class reaching 15. The main tectonic elements of the area are the faults that control the Meso-Cenozoic depressions. Fragments of these faults correspond to the zones of occurrence of earthquakes with a magnitude of 5.5–6.0. Therefore, the study of the seismic process, the features of the manifestation of seismicity, and the assessment of the seismic hazard of this territory are currently given special importance. The research results are aimed at developing methods for studying and predicting the seismic effects of large earthquakes in the BMR. As a result, the most probable seismic-soil models are formed for various thicknesses of loose deposits, differing in their composition and state, taking into account the depth of bedrock occurrence. The available seismogeological and geophysical information and the data obtained by us on the study of engineering and seismological conditions for the construction of a number of industrial and civil facilities are used. According to the records of the last large earthquakes by permanent seismic stations, a single initial signal was formed for the accepted level of initial seismicity. When using it for the constructed models and implementing theoretical calculations, a comparative analysis of the effect of near-surface inhomogeneities on the initial seismic signal was carried out using a set of main indicators of seismicity manifestation: seismic characteristics (accelerograms, spectra, and frequency characteristics) and their parameters (maximum accelerations and prevailing and resonant frequencies). The data presented for the prevailing varieties of soils of various conditions lead to the possibility for their use in zoning the seismic hazard of the study area. [ABSTRACT FROM AUTHOR]

We study the impact of the in-medium mass splitting between bosons and anti-bosons on their spectra and elliptic flow. The in-medium mass splitting may cause a separation in the transverse momentum spectra, as well as a division in the elliptic flow between bosons and anti-bosons. The magnitude of this effect becomes greater as the in-medium mass splitting increases. With the increasing rapidity, the splitting effect of the spectra increases and the splitting effect of the elliptic flow decreases. These phenomena may provide a way to differentiate whether the influences on boson and anti-boson in the medium are consistent. [ABSTRACT FROM AUTHOR]

The results of a spectral survey of the region of massive star formation DR21OH in the 4-mm wavelength range are presented. Sixty-nine molecules and their isotopologues have been detected, ranging from simple diatomic or triatomic species such as SO, SiO and CCH, to complex organic molecules such as CH3OCHO or CH3OCH3. The obtained results qualitatively repeat the results of the survey of the same source at 3 mm. The inventories of molecules found at 3 and 4 mm overlap to a great extent. However, at 4 mm we found a number of species that have no allowed transitions in the 3-mm wavelength range, e.g., DCN, DNC, or SO+. The bulk of the molecules detected at 4 mm are those that are common for dense cores, e.g., HC3N or CH3CCH, but some of the detected species are typical for hot cores. The latter include complex organic molecules CH3OCHO, CH3CH2OH, CH3OCH3, etc. However, the detected emission of these molecules probably arises in a gas heated to 30 K only. Nine molecules, including complex species CH3C3N, CH3CH2CN, CH3COCH3, were found by spectral line stacking. This demonstrates the prospects of the method in the study of molecular clouds. [ABSTRACT FROM AUTHOR]

In the experiment, the morphology of heavy metals (Pb, Cr, Cd, and Ni, HMs) was characterized using flame atomic absorption spectroscopy. In addition, Fourier transform infrared spectroscopy (FTIR) and three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEM) were used to characterize the correlation between environmental factors and metal morphology in the rotting compost from several angles. The results showed that the humus treated with wood vinegar solution had a high degree of humification and rich aromatic structure. FTIR spectroscopy confirmed that the degree of humus aromatization gradually increased during the composting process, which enhanced the complexation of humus (HS) with HMs but had less effect on Ni. In addition, the optimum concentration of wood vinegar (WV) was determined to be 1.75%. The results of the study showed that in the Pb passivation treatment group, the proportion of soluble (Red) and exchangeable states (Exc) converted to oxidized (Oxi) and residual states (Res) was 8%, 14%, 6%, 1%, and 12% in the CK, T1, T2, T3, and T4 treatment groups, respectively; in the Cr passivation treatment group, the proportion of Cr-Red and Cr-Exc converted to oxidized and residual states was 31%, 33%, 25%, 29%, and 25%; in the Cd passivation treatment group, the proportions of Cd-Red and Cd-Exc converted to oxidized and residual states were 5%, 15%, 4%, 9%, and 11%, respectively; whereas the Ni treatment group did not show any significant passivation effect. The proportion of Pb-Oxi was relatively stable, Cr-Oxi was converted to Cr-Res, whereas Cd showed the conversion of Cd-Oxi to Cd-Exc. SUVA254 and SUVA280 showed significant positive correlations with Pb-Res, Cr-Res and Ni-Res, and significant positive correlations with moisture content (MC); whereas MC was significantly negatively correlated with each form of HMs. Total potassium (TK), total nitrogen (TN), and both carbon (TOC) were negatively correlated with Pb-Res and Pb-Exc. Structural equation modeling verified the relationship between environmental factors and HMs, and the composting results showed that the addition of biochar (BC) and a higher percentage of WV could increase compost decomposition and passivate HMs to improve its agronomic function. [ABSTRACT FROM AUTHOR]

Substituted quinazolines of various degrees of saturation and functionalization possess a wide spectrum of biological activity, in particular, anticancer activity, which predetermines the importance of obtaining new representatives of this type of compounds and studying their practically useful properties. Methods for the preparation of 2-cyanoiminoquinazolines are poorly described in the literature, while their properties and oxidation reactions have not been studied at all. We have analyzed the stability of tautomeric forms of 2-cyanoiminoquinazolines, determined the activation energy of their formation using quantum-chemical calculations, studied their transformation under the action of strong oxidants (CrO3/AcOH, NaNO2/AcOH). Selective aromatization of the azoheterocycle and hydrolysis of the -CN-group to form 2-aminocarbamoylquinazoline occurred during oxidation. An increase in temperature from 120 to 160° C (using CrO3) resulted in the formation of 2-nitrosoquinazoline. The structure of our new obtained substances was established by spectral methods (IR, 1H, 13C NMR, HSQC, NOESY), a scheme of their formation has been proposed.

Abstract Purpose Eighty percent of patients infected by SARS-CoV-2 report persistence of one symptom beyond the 4-week convalescent period. Those with orthostatic tachycardia and orthostatic symptoms mimicking postural tachycardia syndrome, they are defined as Long-COVID POTS [LCP]. This case-control study investigated potential differences in autonomic cardiovascular regulation between LCP patients and healthy controls. Methods Thirteen LCP and 16 healthy controls, all female subjects, were studied without medications. Continuous blood pressure and ECG were recorded during orthostatic stress test, respiratory sinus arrhythmia, and Valsalva maneuver. Time domain and power spectral analysis of heart rate [HR] and systolic blood pressure [SBP] variability were computed characterizing cardiac autonomic control and sympathetic peripheral vasoconstriction. Results LCP had higher deltaHR (+ 40 ± 6 vs. + 21 ± 3 bpm, p = 0.004) and deltaSBP (+ 8 ± 4 vs. -1 ± 2 mmHg, p = 0.04) upon standing; 47% had impaired Valsalva maneuver ratio compared with 6.2% in controls (p = 0.01). Spectral analysis revealed that LCP had lower RMSSD (32.1 ± 4.6 vs. 48.9 ± 6.8 ms, p = 0.04) and HFRRI, both in absolute (349 ± 105 vs. 851 ± 253ms2, p = 0.03) and normalized units (32 ± 4 vs. 46 ± 4 n.u., p = 0.02). LFSBP was similar between groups. Conclusions LCP have reduced cardiovagal modulation, but normal sympathetic cardiac and vasoconstrictive functions. Impaired parasympathetic function may contribute to the pathogenesis of Long-COVID POTS syndrome.

The present study is a theoretical investigation into the structural evolution, electronic properties, and photoelectron spectra of phosphorus-doped boron clusters PBn0/− (n = 3–17). The results of this study revealed that the lowest energy structures of PBn− (n = 3–17) clusters, except for PB17−, exhibit planar or quasi-planar structures. The lowest energy structures of PBn (n = 3–17), with the exceptions of PB7, PB9, and PB15, are planar or quasi-planar. The ground state of PB7 has an umbrella-shaped structure, with C6V symmetry. Interestingly, the neutral cluster PB15 has a half-sandwich-like structure, in which the P atom is attached to three B atoms at one end of the sandwich, exhibiting excellent relative and chemical stability due to its higher second-order energy difference and larger HOMO–LUMO energy gap of 4.31 eV. Subsequently, adaptive natural density partitioning (AdNDP) and electron localization function (ELF) analyses demonstrate the bonding characteristics of PB7 and PB15, providing support for the validity of their stability. The calculated photoelectron spectra show distinct characteristic peaks of PBn− (n = 3–17) clusters, thus providing theoretical evidence for the future identification of doped boron clusters. In summary, our work has significant implications for understanding the structural evolution of doped boron clusters PBn0/− (n = 3–17), motivating further experiments regarding doped boron clusters.