Direct Determination Research Articles

WASP 0346-21: An EL CVn-type Eclipsing Binary with Multiperiodic Pulsations in a Triple System

Very Large Telescope/UVES spectroscopic and Transiting Exoplanet Survey Satellite (TESS) photometric observations for WASP 0346-21 allow the direct determination of its physical properties, along with the detection of a circumbinary object and oscillating signals. The high-resolution spectra yielded the radial velocities of all three stars and the atmospheric parameters of T eff,A = 7225 ± 42 K, [M/H] = 0.30 ± 0.03 dex, and v A sini = 78 ± 5 km s−1 of the primary component. The combined analysis of these observations resulted in the fundamental parameters of the eclipsing components and the third light of l 3 = 0.043 ± 0.004, which is consistent with the light contribution of the tertiary star observed in the echelle spectra. WASP 0346-21 A resides within the overlapping main-sequence domain of δ Sct and γ Dor variables, while the secondary component of M B = 0.185 ± 0.013 M ⊙, R B = 0.308 ± 0.023 R ⊙, T eff,B = 10,655 ± 146 K, and L B = 1.09 ± 0.17 L ⊙ matches well with the low-mass white dwarf (WD) model for Z = 0.01, corresponding to the thick disk population classified by the Galactic kinematics. Multifrequency analyses were performed on the residual TESS data after removing the binarity effects. The low frequencies around 26.348 day−1 and 17.683 day−1 are δ Sct pulsations originating from WASP 0346-21 A, and the high frequencies of 97.996 day−1 and 90.460 day−1 are considered to be extremely low-mass WD oscillations. These results demonstrate that WASP 0346-21 is a hierarchical triple system, consisting of an EL CVn binary with multiperiodic pulsations in each component and a distant outer tertiary.

Targeting Plasmodium falciparum IspD in the Methyl-d-erythritol Phosphate Pathway: Urea-Based Compounds with Nanomolar Potency on Target and Low-Micromolar Whole-Cell Activity.

The methyl-d-erythritol phosphate (MEP) pathway has emerged as an interesting target in the fight against antimicrobial resistance. The pathway is essential in many human pathogens, including Plasmodium falciparum (Pf), but is absent in human cells. In the present study, we report on the discovery of a new chemical class targeting IspD, the third enzyme in the pathway. Exploration of the structure-activity relationship yielded inhibitors with potency in the low-nanomolar range. Moreover, we investigated the whole-cell activity, mode of inhibition, metabolic, and plasma stability of this compound class, and conducted in vivo pharmacokinetic profiling on selected compounds. Lastly, we disclosed a new mass spectrometry (MS)-based enzymatic assay for direct IspD activity determination, circumventing the need for auxiliary enzymes. In summary, we have identified a readily synthesizable compound class, demonstrating excellent activity and a promising profile, positioning it as a valuable tool compound for advancing research on IspD.

Direct determination of electron and hole temperatures from continuous-wave photoluminescence measurements

Direct determination of electron and hole temperatures from continuous-wave photoluminescence measurements

Internal Marketing As A Key To Strategic Human Resources Management In The Education Industry In The Context Of The COVID-19 Pandemic

Several studies prove the relevance of internal marketing in promoting job satisfaction and life satisfaction among professionals. During the COVID-19 Pandemic, educational institutions were faced with a set of challenges that forced the redefinition of strategies appropriate to the context experienced, with internal marketing being a key factor in redefining these same strategies. This study aims to evaluate whether internal marketing is a catalyst for professional satisfaction and life satisfaction among professionals in the Education industry active in Portugal during the COVID-19 Pandemic. To this end, a conceptual research model was developed and 4 study hypotheses were postulated to investigate the purpose of this research based on a quantitative methodology applied to a convenience sample (n=167). The findings obtained proved to be statistically significant, showing internal marketing as a direct and positive predictor of commitment, professional satisfaction and also satisfaction with life. Besides, job satisfaction has been confirmed as a direct and positive determinant of employee performance, commitment, loyalty and satisfaction with life. Finally, commitment was too confirmed as a predictor of employee satisfaction and loyalty. Thus, this research presents itself as an added value for both science and the education industry, as it makes important contributions to the country's educational institutions and enables them to perceive various determinants of professional satisfaction, commitment, employee performance and loyalty, so as to improve strategies that support organizational sustainability and the well-being of educational agents and, in turn, of the students themselves.

Determination of Coefficients of Decomposition of a Nonlinear Characteristic into a Power Series

The problem of monitoring the parameters of nonlinear elements included in various electrical devices is considered. A new algorithm for reproducing the nonlinear current-voltage characteristic of a device based on the measurement results has been proposed and investigated, which has several advantages over the known ones, allowing, in particular, to obtain an analytical representation of the current-voltage characteristic in real time. The proposed algorithm is based on the direct determination of the coefficients of the polynomial approximation of the current-voltage characteristic. A review of scientific research done to date by other authors dealing with this problem has also been carried out. Formulas for determining the amplitudes of current harmonics through power series coefficients and voltage amplitudes on a nonlinear element are obtained. Binomial coefficients are used to facilitate intermediate calculations. The relations for the zero, odd and even harmonics of the current are obtained, as well as analytical expressions for the coefficients of the polynomial approximation. An experimental study of the proposed method was carried out, according to the results of which an assessment of its accuracy was made. The use of the proposed method significantly simplifies the processing and reduces the measurement time of nonlinear VAC.

Distance estimation of gamma-ray-emitting BL Lac objects from imaging observations

The direct redshift determination of BL Lac objects is highly challenging as the emission in the optical and near-infrared bands is largely dominated by the non-thermal emission from the relativistic jet, which points very close to our line of sight. Therefore, the optical spectra of BL Lac objects often show no spectral lines from the host galaxy. In this work, we aim to overcome this difficulty by attempting to detect the host galaxy and derive redshift constraints based on assumptions on the galaxy magnitude (`imaging redshifts'). Imaging redshifts were derived by obtaining deep optical images under good seeing conditions, making it possible to detect the host galaxy as a weak extension of the point-like source. We then derived the imaging redshift by using the host galaxy as a standard candle, employing two different methods. We determine the imaging redshift for 9 out of 17 blazars that we observed as part of this programme. The redshift range of these targets is 0.28-0.60, and the two methods used to derive the redshift give very consistent results within the uncertainties. We also performed a detailed comparison of the imaging redshifts with those obtained using other methods, such as direct spectroscopic constraints or looking for groups of galaxies close to the blazar. We show that the constraints from the different methods are consistent and that combining the three constraints narrows down the redshift. For example, in the case of J2156.0+1818, which is the most distant source for which we detect the host galaxy, the redshift range is narrowed to $0.63<z<0.71$. This makes the source interesting for future studies of extragalactic background light in the Cherenkov Telescope Array Observatory era.

Determination of optimal directions of the wave vector of the phase holographic grating in cubic photorefractive crystal

The dependence of the change in the components of the inverse permittivity tensor of a cubic photorefractive Bi12SiO20 crystal on the direction of the wave vector of holographic grating in the crystal coordinate system has been studied. It is shown that, when recording a phase hologram, the largest change in the refractive index of Bi12SiO20 crystal is attained when the holographic grating wave vector is oriented along symmetrically equivalent 111 directions. The maximum possible modulation amplitude of the refractive index of a holographic grating with the wave vector oriented along the 110 directions is found to exceed that in the case of orientation along the 100 directions. The components of the inverse permittivity tensor of Bi12SiO20 crystal were calculated taking into account that a phase hologram is recorded under linear electro-optic, photoelastic, and inverse piezoelectric effects.

An improved dual shear unified strength model (IDSUSM) considering strain softening effect

This study proposes an improved dual shear unified strength model by introducing the plastic internal variable which reflects the collective effects of strain softening, intermediate principal stress and unequal strength under tension and compression. The improved model is then simplified into simple forms for typical stress states, including uniaxial tension and compression, plane stress pure shear and tri-axial stress states. The smooth method and conjugate gradient method are utilized to facilitate its numerical implementation, avoiding numerical singularity and non-convergence in the solution process. The physical meanings of the parameters are further clarified and their values for self-compacting concrete are determined from the results of triaxial compression tests through a combination of direct determination, equation solution and back propagation (BP) neural network optimization. Validated against the test results, the improved model gives a more accurate prediction than the traditional dual shear unified strength model and Mohr-Coulomb model, in terms of both the overall trend and representative values. Validation results show that the improved model is applicable to materials for which the compressive strength is greater than the tensile strength and the tensile strength is greater than the shear strength.

Uneven changes in air and crown temperatures associated with snowpack changes affect the phenology of overwintering cereals

Time series analysis of overwintering cereals in snowy areas has revealed several phenological patterns associated with climate changes in winter. Herein, to investigate the recent effect of climatic variations on overwintering cereals, we investigated the phenology over multiple decades at three snowy region sites with an air temperature (Tair) increase trend of 0.48–1.09 °C/decade. Our findings were as follows: heading trends differed within the same cultivar at different sites; phenology was promoted with increasing temperatures in cooler regions and decreasing snow duration in regions with heavy snow; crown temperature (Tcrown) was a more direct determinant than Tair in phenology estimation model in regions with heavy snow. A thermal gap of more than a few degrees Celsius between Tair and Tcrown, owing to the insulation effect of snowpack, affected the phenology of overwintering cereals. A shorter snow cover period promoted phenology in locations with temperatures >0 °C. Subsequently, we found that when the thermal gap was >0 °C of the growing temperature range, Tcrown directly helped determine the phenology of overwintering cereals, and irrespective of the warming trend, the periodic inflow of cold air into the northern mid-latitudes of the Northern Hemisphere and associated snow cover changes dominated Tcrown, resulting in annual phenological anomalies with a range of fluctuations of approximately 1 month. The trend of increasing Tair during spring in northern Japan is consistent with the global trend, with a pronounced trend of advancing phenology reaching >4 days/decade in a typical cooler location experiencing snowmelt in March.

Practical high-resolution spectroscopy with a spatial heterodyne spectrometer: Determination of instrumental function for lineshape recovery

The spatial heterodyne spectrometer (SHS) is a well-recognized platform for its high resolving power in various use cases of spectroscopy. Same as other spectrometer topologies, the SHS, unfortunately, also suffers from classical challenges such as distorted lineshape due to the instrumental function. The goal of this work is to tackle this persisting issue through a simple numerical approach. With the inherent characteristics of an SHS interferogram, we report the direct extraction and determination of the instrumental function in its numerical representation from an SHS interferogram; this instrumental function was further used for spectral data processing that enables significant improvements in spectral resolution through deconvolution algorithms.Here, we systematically discuss the recognition of the embedded instrumental function among various ingredients within an interferogram. To verify the numerical approach, lithium was chosen as the model sample, resembling the use of SHS in an isotopic analysis application. Specifically, the resonance transition of lithium D-lines (2P1/2,3/2 ← 2S1/2) was selected to assess the performance of the spectral processing. With the spectral deconvolution, the spectral features that represent the 6Li and 7Li were nearly baseline-separated, allowing for the accurate measure of the isotopic abundance without external references or algorithm adjustments (e.g., curve fitting).

Direct determination of chronic myeloid leukemia prevalence in Lombardy-Italy: Global implications.

Lombardy represents the largest region of Italy by population, with almost 10 million residents, a dimension similar to a medium size country like Sweden or Belgium. The CML subcommittee of the Lombardy Hematology Network (REL-CML) conducted a study at the beginning of 2023. Prevalence was calculated by direct input from the 21 centers participating in REL-CML. Tyrosine Kinase Inhibitors (TKI) prescription records collected from the ARIA regional registry were used to estimate the number of CML patients followed in smaller centers not participating in REL-CML. A total of 2285 patients were registered, representing a prevalence of 0.23 ‰. These data were compared to a similar census conducted in 2005, at the beginning of the TKI era, where a prevalence of 0.029‰ was calculated. This indicates that an almost 10 times increase took place during this period of time. Imatinib represents the most frequently prescribed first-line TKI; its use in 2022 still represented 75% of total first line prescriptions. An increased concentration of the care of CML patients in specialized REL centers with a decreased dispersion of patients in small centers was also evident over this 18year period of time. Nineteen % of patients discontinued treatment, highlighting persisting logistical and biological challenges; one some recommendations on CML management are included to this aim.

Additional applications of the Lambert W function to solid state physics

Analytical solutions are always desirable in physics for the sake of mathematical exactness and physical insight. In this study, I obtain closed-form analytical expressions for various physical quantities taken from solid state physics. More precisely, I derive analytical expressions in terms of the Lambert W function for the work function and the field-enhancement factor of a field emitting material from the Fowler–Nordheim equation. Additionally, I derive similar analytical expressions for the localization length and the density of states in amorphous semiconductors from the Mott hopping conductivity. Similarly, I also derive analytical formulae based on the Lambert W function to compute the extrinsic-intrinsic transition temperature in a partially compensated semiconductor and the Kondo exchange coupling constant. All the obtained results are exact and explicit. Moreover, some of them allow a direct determination of some physical quantities of interest compared to their indirect determination from semi-logarithmic experimental plots. The findings of this paper are accessible and suitable for students enrolled in graduate solid state physics courses.

The moss growth optimization (MGO): concepts and performance

Abstract Metaheuristic algorithms are increasingly utilized to solve complex optimization problems because they can efficiently explore large solution spaces. The moss growth optimization (MGO), introduced in this paper, is an algorithm inspired by the moss growth in the natural environment. The MGO algorithm initially determines the evolutionary direction of the population through a mechanism called the determination of wind direction, which employs a method of partitioning the population. Meanwhile, drawing inspiration from the asexual reproduction, sexual reproduction, and vegetative reproduction of moss, two novel search strategies, namely spore dispersal search and dual propagation search, are proposed for exploration and exploitation, respectively. Finally, the cryptobiosis mechanism alters the traditional metaheuristic algorithm’s approach of directly modifying individuals’ solutions, preventing the algorithm from getting trapped in local optima. In experiments, a thorough investigation is undertaken on the characteristics, parameters, and time cost of the MGO algorithm to enhance the understanding of MGO. Subsequently, MGO is compared with 10 original and advanced CEC 2017 and CEC 2022 algorithms to verify its performance advantages. Lastly, this paper applies MGO to four real-world engineering problems to validate its effectiveness and superiority in practical scenarios. The results demonstrate that MGO is a promising algorithm for tackling real challenges. The source codes of the MGO are available at https://aliasgharheidari.com/MGO.html and other websites.

Total organic carbon quantification in soils and sediments: Performance test of a modified sample preparation method

The total organic carbon (TOC) concentration of particulate samples is a key parameter to characterize soils and sediments. To demonstrate the applicability and reliability of a modified sample preparation method for the direct measurement of TOC contents in suspended particulate samples, we analyzed five certified reference materials (CRMs) with varying TOC concentrations using a Shimadzu TOC-L CPH analyzer. Measured values were calibrated with a multi-point curve that cover the full range of the expected TOC concentrations and the results were validated using statistical values and measures. The method validation reveals that the measurements are accurate and precise for CRMs from marine and soil contexts, but show a low accuracy for the CRM containing polycyclic aromatic hydrocarbons (PAHs). This demonstrates the applicability and reliability of the modified preparation method for direct TOC determination of suspended particulate samples. Therefore, it is relevant for a broader community, beyond geosciences, and for users employing devices of other manufacturers to analyze TOC in suspended particulate samples.•Modified preparation method uses reduced sample weights and yields accurate and precise results.•Cost-efficient and environmentally friendly alternative: reduces waste by saving acid and ultrapure water.•Avoids incomplete dissolution of dolomite by heating acidified samples.

Research on Strategies for Enhancing the Ideological and Political Education Ability of College Counselors under the New Situation: A Case Study of Wenzhou Polytechnic

With the rapid development of higher vocational education, higher vocational colleges play a more and more important role in training high-quality technical talents and serving regional economic development. In this context, as the backbone of ideological and political education of students in higher vocational colleges, counselors bear the heavy responsibility of guiding students to shape a correct world outlook, outlook on life and values. The construction of their team is not only related to the depth and breadth of students' ideological and political education, but also a direct determinant of the effectiveness of ideological and political education. Under the new historical conditions, it has become an urgent task to strengthen the ideological and political education ability of counselors in higher vocational colleges. This paper is committed to analyzing the current situation of ideological and political education of counselors in higher vocational colleges under the new situation, and deeply discussing how to improve the ideological and political education quality of counselors in multiple dimensions.

Determination of chromium traces by atomic ionization spectroscopy in aqueous standard solutions and in gallium arsenide using the «rod – flame» atomization system

The results of the determination of trace amounts of chromium in aqueous standard solutions of chromium and in high purity gallium arsenide using atomic ionization spectroscopy are presented. Single — and two-step schemes of chromium atom excitation from the ground state 3d54s 7S3 to septet states 3d54p 7P2,3,4, 3d44s4p 7P2,3,4 were studied using a «rod – flame» atomizer. A mechanism of forming atomic-ionization signal for two-step excitation schemes is revealed. The most effective two step excitation schemes for chromium atoms were determined and experimentally studied at different wavelengths λ1 = 425.4 nm, λ2 = 451.4 nm; λ1 = 425.4 nm, λ2 = 426.1 nm. The low limit of chromium detection in aqueous water solutions was 50 pg/ml. The analytical potentiality of the «rod – flame» system for determining traces of chromium in gallium arsenide solutions has been demonstrated. The possibility of determining traces of chromium in gallium arsenide using a flame – rod atomizer at a level of 5 × 10–7 % is demonstrated. Two methods are proposed to increase the selectivity and sensitivity of atomic-ionization determination of chromium: optimization of the temperature program of the flame – rod atomizer and the use of two-stage excitation of chromium atoms. It is shown that the main interfering factor is the background attributed to the matrix ionization. Methods are proposed to reduce or eliminate the matrix impact, which ensure direct determination of elements in samples.

Refining Children's exposure assessment to NO2, SO2, and O3: Incorporating indoor-to-outdoor concentration ratios and individual daily routine

Exposure to air pollutants like sulfur dioxide (SO2), nitrogen oxides (NOx), and ozone (O3) is associated with adverse health effects, particularly with exacerbations of asthma symptoms and new asthma cases in both children and adults. While fixed-site monitoring (FSM) stations are commonly used in air pollutant exposure studies, they may not fully capture personal exposures due to limitations such as inadequate consideration of daily routines and indoor/outdoor concentration variations. In this study, to enhance the accuracy of personal exposure calculated by using FSM data, individual's daily activity routine, encompassing both indoor and outdoor environments, were incorporated by using indoor-to-outdoor concentration ratios. Three methodologies were compared to assess the accuracy of exposure calculations: (i) direct exposure determination employing passive samplers (PS), (ii) personal exposure calculated using FSM data alone, and (iii) personal exposure calculated using FSM data refined by integrating local average individual daily activity routines and indoor-to-outdoor ratios. The results demonstrate that the refined method (iii) yields substantial improvements in estimated exposure levels, reducing the average error from 1.4% to 0.4% for NO2, from 72.1% to 12.7% for SO2, and from 323.4% to 24.9% for O3.

Comparison and review of international guidelines for treating asthma in children.

Asthma, the most common chronic disease, is characterized by airway inflammation and airflow obstruction. The World Health Organization estimates that approximately 300 million people worldwide have asthma, 30% of whom are pediatric patients. Asthma is a major cause of morbidity that can lead to hospitalization or death in severe pediatric cases. Therefore, it is necessary to provide children with objective and reliable treatment according to consistent guidelines. Several institutes, such as the Global Institute for Asthma, National Heart, Lung, and Blood Institute, British Thoracic Society, Japanese Society of Pediatric Allergy and Clinical Immunology, and Korean Academy of Asthma, Allergy, and Clinical Immunology have published and revised asthma guidelines. However, since recommendations differ among them, confusion persists regarding drug therapy for pediatric asthma patients. Additionally, some guidelines have changed significantly in recent years. This review investigated the latest changes in each guideline, compared and analyzed the recommendations, and identified the international trends in pediatric asthma drug therapy. The findings of this review may aid determinations of the future direction of the Korean guidelines for childhood asthma.

Substrate-Based Ligand Design for Phenazine Biosynthesis Enzyme PhzF.

The phenazine pyocyanin is an important virulence factor of the pathogen Pseudomonas aeruginosa, which is on the WHO list of antibiotic resistant "priority pathogens". In this study the isomerase PhzF, a key bacterial enzyme of the pyocyanin biosynthetic pathway, was investigated as a pathoblocker target. The aim of the pathoblocker strategy is to reduce the virulence of the pathogen without killing it, thus preventing the rapid development of resistance. Based on crystal structures of PhzF, derivatives of the inhibitor 3-hydroxyanthranilic acid were designed. Co-crystal structures of the synthesized derivatives with PhzF revealed spacial limitations of the binding pocket of PhzF in the closed conformation. In contrast, ligands aligned to the open conformation of PhzF provided more room for structural modifications. The intrinsic fluorescence of small 3-hydroxyanthranilic acid derivatives enabled direct affinity determinations using FRET assays. The analysis of structure-activity relationships showed that the carboxylic acid moiety is essential for binding to the target enzyme. The results of this study provide fundamental structural insights that will be useful for the design of PhzF-inhibitors.

Refined determination of the weak mixing angle at low energy

The weak mixing angle is a fundamental parameter of the electroweak theory of the standard model whose measurement in the low-energy regime is still not precisely determined. Different probes are sensitive to its value, including atomic parity violation, coherent elastic neutrino-nucleus scattering, and parity-violating electron scattering on different nuclei. In this work, we attempt for the first time to combine all these various determinations by performing a global fit that also takes into account the unavoidable dependence on the experimentally poorly known neutron distribution radius of the nuclei employed, for which a new measurement using proton-cesium elastic scattering became available. By using all present direct determinations of the neutron distribution radius of cesium, we find sin2ϑW=0.2396−0.0019+0.0020, which should supersede the previous value determined from atomic parity violation on cesium. When including electroweak only, but also indirect, determinations of the neutron distribution radius of cesium, the uncertainty reduces to 0.0017, maintaining the same central value and showing excellent agreement independently of the method used. Published by the American Physical Society 2024