Spectrum Of Types Research Articles

Predicting the occurrence of rogue waves in short-crested mixed seas

ABSTRACT In this paper we have for the first time proposed a novel transformed Gaussian process method for the estimation of rogue wave occurrence in a short crested mixed sea. The saddle point approximation of a specific joint density is utilised to further improve the computational efficiency of the proposed method. The proposed method has been applied to forecast the rogue wave occurrence in four short-crested mixed sea states, two with directional wave spectra based on measured surface elevation data at the coast of Yura, and another two with typical directional bimodal wave spectra. It is shown in these four cases that the proposed method can offer more accurate forecasting results than those obtained from the linear simulation method, from the transformation based on Hermite polynomials and from using the Rayleigh distribution model. It is also demonstrated that the proposed method is more efficient than the nonlinear simulation method.

The Need for Psychiatric Assessment in Children with Down Syndrome and Factors Affecting Their Use of Mental Health Services: A Cross-Sectional Study from Turkey

Objective. Down syndrome (DS) is the most common cause of intellectual disability. Children with DS may have difficulty accessing psychiatric services because their mental health problems are often unrecognized. This study aimed to assess the mental health needs of children with Down syndrome and the elements that may affect their access and referral to psychiatric services. Methods. In this single-center cross-sectional study, we evaluated 72 children with Down syndrome and assessed the factors affecting their use of mental health services by using a questionnaire completed by parents. We compared the clinical symptom profiles of young preschool-aged children with Down syndrome (n = 26) with typical (n = 26), developmental delay (n = 15), and autism spectrum disorder (ASD) group (n = 28) to evaluate mental health problems. The Schedule for Affective Disorders and Schizophrenia for School-Aged Children: Present and Lifetime Version DSM-5 (K-SADS-PL) was administered. Parents completed the child behavior check list for ages 6–18 and 1½-5, depending on the child’s age. Results. Although most patients with Down syndrome (51.4%) had psychiatric symptoms reported by parents at the initial assessment, the most frequent reason (62.5%) for applying to our psychiatric clinic was to submit an application for a medical report. The majority of patients with Down syndrome (56%) had a psychiatric disorder, and attention deficit and hyperactivity disorder was the most common diagnosis. Conclusion. Clinicians should not overlook the need for psychiatric assessment, early diagnosis, and collaboration between pediatricians and child psychiatrists, which are crucial during medical evaluation and follow-up of children with Down syndrome.

Observational Characteristics of Radiation-mediated Shocks in Photospheric Gamma-Ray Burst Emission

Emission from the photosphere in gamma-ray burst jets can be substantially affected by subphotospheric energy dissipation, which is typically caused by radiation-mediated shocks. We study the observational characteristics of such emission, in particular the spectral signatures. Relevant shock initial conditions are estimated using a simple internal collision framework, which then serve as inputs for a radiation-mediated shock model that generates synthetic photospheric spectra. Within this framework, we find that if the free fireball acceleration starts at r 0 ∼ 1010 cm, in agreement with hydrodynamical simulations, then the typical spectrum consists of a broad, soft power-law segment with a cutoff at high energies and a hardening in X-rays. The synthetic spectra are generally well fitted with a standard cutoff power-law (CPL) function, as the hardening in X-rays is commonly outside the observable energy range of current detectors. The CPL-fits yield values for the low-energy index, α, and the peak energy, E peak, that are centered around ∼ −0.8 and ∼220 keV, respectively, similar to typical observed values. We also identify a nonnegligible parameter region for what we call optically shallow shocks: shocks that do not accumulate enough scatterings to reach a steady-state spectrum before decoupling and thereby produce more complex spectra. These occur for optical depths , where u u = γ u β u is the dimensionless specific momentum of the upstream as measured in the shock rest frame.

Structural and Chemical Properties of NiOx Thin Films: Oxygen Vacancy Formation in O2 Atmosphere.

NiOx films on Si(111) were put in contact with oxygen at elevated temperatures. During heating and cooling in oxygen atmosphere Near Ambient Pressure (NAP)-XPS and -XAS and work function (WF) measurements reveal the creation and replenishing of oxygen vacancies in dependence of temperature. Oxygen vacancies manifest themselves as a distinct O1s feature at 528.9 eV on the low binding energy side of the main NiO peak as well as by a distinct deviation of the Ni2p3/2 spectral features from the typical NiO spectra. DFT calculations reveal that the presence of oxygen vacancies leads to a charge redistribution and altered bond lengths of the atoms surrounding the vacancies causing the observed spectral changes. Furthermore, we observed that a broadening of the lowest energy peak in the O K-edge spectra can be attributed to oxygen vacancies. In the presence of oxygen vacancies, the WF is lowered by 0.1 eV.

Secondary Proton Beam Instability in a Turbulent Solar Wind at 50 R ⊙

We investigate a secondary proton beam instability coexisting with the ambient solar wind turbulence at 50 R ☉. Three-dimensional hybrid numerical simulations (particle ions and a quasi-neutralizing electron fluid) are carried out with the plasma parameters in the observed range. In the turbulent background, the particle distribution function, in particular the slope of the “bump-on-tail” responsible for the instability, is time-dependent and inhomogeneous. The presence of the turbulence substantially reduces the growth rate and saturation level of the instability. We derive magnetic power spectra from the observational data and perform a statistical analysis to evaluate the average turbulence intensity at 50 R ☉. This information is used to link the observed frequency spectrum to the wavenumber spectrum in the simulations. We verify that Taylor’s frozen-in hypothesis is valid for this purpose to a sufficient extent. To reproduce the typical magnetic power spectrum of the instability observed concurrently with the background turbulence, an artificial spacecraft probe is run through the simulation box. The thermal-ion instabilities are often seen as power elevations in the kinetic range of scales above an extrapolation of the turbulence spectrum from larger scales. We show that the elevated power in the simulations is much higher than the background level. Therefore, the turbulence at the average intensity does not obscure the secondary proton beam instability, as opposed to the solar wind at 1 au, in which the ambient turbulence typically obscures thermal-ion instabilities.

Detecting, Distinguishing, and Spatiotemporally Tracking Photogenerated Charge and Heat at the Nanoscale.

Since dissipative processes are ubiquitous in semiconductors, characterizing how electronic and thermal energy transduce and transport at the nanoscale is vital for understanding and leveraging their fundamental properties. For example, in low-dimensional transition metal dichalcogenides (TMDCs), excess heat generation upon photoexcitation is difficult to avoid since even with modest injected exciton densities exciton-exciton annihilation still occurs. Both heat and photoexcited electronic species imprint transient changes in the optical response of a semiconductor, yet the distinct signatures of each are difficult to disentangle in typical spectra due to overlapping resonances. In response, we employ stroboscopic optical scattering microscopy (stroboSCAT) to simultaneously map both heat and exciton populations in few-layer MoS2 on relevant nanometer and picosecond length- and time scales and with 100-mK temperature sensitivity. We discern excitonic contributions to the signal from heat by combining observations close to and far from exciton resonances, characterizing the photoinduced dynamics for each. Our approach is general and can be applied to any electronic material, including thermoelectrics, where heat and electronic observables spatially interplay, and it will enable direct and quantitative discernment of different types of coexisting energy without recourse to complex models or underlying assumptions.

Шумоизолирующий кожух с резонаторными элементами

Constant exposure to industrial noise has a negative impact on the human body. That is why increased attention is paid to the fight against noise, the rationing of industrial noise and vibrations was adopted. One of the effective methods to reduce the noise emitted by the operating equipment is the use of noise-insulating casings. The casing, as a rule, contains an outer skin made of steel sheet, a sound-absorbing lining of the inner skin, a perforated lining of a sound-absorbing coating. A typical octave spectrum of radiation sound pressure levels near the machine has a maximum near the frequency of 500 Hz, and the highest casing efficiency (insertion loss) is achieved in the frequency range of 1000–4000 Hz. The purpose of the study presented in the article is to improve the acoustic properties of the noise-insulating casing in the medium and low-frequency sound spectrum. To accomplish this task, the author proposes integrating resonator elements, in particular, Helmholtz resonators, into the structure of the noise-insulating casing. The natural resonant frequencies of Helmholtz acoustic resonators are determined considering their necessary frequency tuning, which ensures effective suppression of sound radiation at discrete values of the operating dominant frequencies of operating equipment. To reduce the excitation of structural vibrations and sound, as well as additional sound insulation, the frame walls and casing covers are damped on the outside and inside with a layer of vibration-damping material. Significant absorption of sound waves generated by operating equipment is ensured by lining the casing walls with effective sound-absorbing panels made of porous material, lined, in turn, with an external protective sound-transparent layer. The design of a noise-insulating casing with resonator elements presented in the study has high acoustic properties in a wide frequency range. Helmholtz resonators built into the casing structure provide sound absorption in 1/3 octave frequency bands centered at 400 and 500 Hz, characterized by a resonant amplification of the sound emitted by the equipment discussed in the article.

XMM-Newton Observations of Two Archival X-Ray Weak Type 1 Quasars: Obscuration Induced X-Ray Weakness and Variability

We report XMM-Newton observations of two examples of an unclassified type of X-ray weak quasars from the Pu et al. survey of X-ray weak quasars in the Chandra archive, SDSS J083116.62+321329.6 at z = 1.797 and SDSS J142339.87+042041.1 at z = 1.702. They do not belong to the known populations of X-ray weak quasars that show broad absorption lines, weak ultraviolet (UV) broad emission lines, or red optical/UV continua. Instead, they display typical quasar UV spectra and spectral energy distributions. In the XMM-Newton observations, both quasars show nominal levels of X-ray emission with typical quasar X-ray spectral shapes (power-law photon indices of and ), displaying strong X-ray variability compared to the archival Chandra data (variability factors of and in terms of the 2 keV flux density). Simultaneous optical (rest-frame UV) spectra indicate no strong variability compared to the archival spectra. Long-term optical/UV and infrared light curves do not show any substantial variability either. We consider that the X-ray weakness observed in the Chandra data is due to X-ray obscuration from a small-scale dust-free absorber, likely related to accretion-disk winds. Such X-ray weak/absorbed states are probably rare in typical quasars, and thus both targets recovered to X-ray nominal-strength states in the XMM-Newton observations.

The Role of Lattice Defects on the Optical Properties of TiO2 Nanotube Arrays for Synergistic Water Splitting.

In this study, we report a facile one-step chemical method to synthesize reduced titanium dioxide (TiO2) nanotube arrays (NTAs) with point defects. Treatment with NaBH4 introduces oxygen vacancies (OVs) in the TiO2 lattice. Chemical analysis and optical studies indicate that the OV density can be significantly increased by changing reduction time treatment, leading to higher optical transmission of the TiO2 NTAs and retarded carrier recombination in the photoelectrochemical process. A cathodoluminescence (CL) study of reduced TiO2 (TiO2-x) NTAs revealed that OVs contribute significantly to the emission bands in the visible range. It was found that the TiO2 NTAs reduced for a longer duration exhibited a higher concentration of OVs. A typical CL spectrum of TiO2 was deconvoluted to four Gaussian components, assigned to F, F+, and Ti3+ centers. X-ray photoelectron spectroscopy measurements were used to support the change in the surface chemical bonding and electronic valence band position in TiO2. Electron paramagnetic resonance spectra confirmed the presence of OVs in the TiO2-x sample. The prepared TiO2-x NTAs show an enhanced photocurrent for water splitting due to pronounced light absorption in the visible region, enhanced electrical conductivity, and improved charge transportation.

Recent application of direct analysis in real time mass spectrometry in plant materials analysis with emphasis on traditional Chinese herbal medicine.

Direct analysis in real time (DART) represents a new generation of ionization techniques that are used to rapidly ionize small molecules under ambient environments. The combination of DART with various mass spectrometry (MS) instruments allows analyzing multiple plant materials, including traditional Chinese herbal medicines (TCHMs), under simple or no sample treatment conditions. This review discussed the DART principles, including devices, ionization mechanisms, and operation parameters. Typical spectra detected by DART-MS were exhibited and discussed. Numerous applications of DART-MS in the fields of plant material and TCHM analysis were reviewed, including compound identification, biomarker discovery, fingerprinting analysis, and quantification analysis. Besides, modifications and improvements of DART-MS, such as hyphenated application with other separation methods, laser-based desorption techniques, and online sampling configuration, were summarized as well.

Breaking wave field statistics with a multi-layer model

The statistics of breaking wave fields are characterised within a novel multi-layer framework, which generalises the single-layer Saint-Venant system into a multi-layer and non-hydrostatic formulation of the Navier–Stokes equations. We simulate an ensemble of phase-resolved surface wave fields in physical space, where strong nonlinearities, including directional wave breaking and the subsequent highly rotational flow motion, are modelled, without surface overturning. We extract the kinematics of wave breaking by identifying breaking fronts and their speed, for freely evolving wave fields initialised with typical wind wave spectra. The$\varLambda (c)$distribution, defined as the length of breaking fronts (per unit area) moving with speed$c$to$c+{\rm d}c$following Phillips (J. Fluid Mech., vol. 156, 1985, pp. 505–531), is reported for a broad range of conditions. We recover the$\varLambda (c) \propto c^{-6}$scaling without wind forcing for sufficiently steep wave fields. A scaling of$\varLambda (c)$based solely on the root-mean-square slope and peak wave phase speed is shown to describe the modelled breaking distributions well. The modelled breaking distributions are in good agreement with field measurements and the proposed scaling can be applied successfully to the observational data sets. The present work paves the way for simulations of the turbulent upper ocean directly coupled to a realistic breaking wave dynamics, including Langmuir turbulence, and other sub-mesoscale processes.

Exploring the Antimicrobial, Anticancer, and Apoptosis Inducing Ability of Biofabricated Silver Nanoparticles Using Lagerstroemia speciosa Flower Buds against the Human Osteosarcoma (MG-63) Cell Line via Flow Cytometry.

Biosynthesized nano-composites, such as silver nanoparticles (AgNPs), can be engineered to function as smart nano-biomedicine platforms for the detection and management of diverse ailments, such as infectious diseases and cancer. This study determined the eco-friendly fabrication of silver nanoparticles using Lagerstroemia speciosa (L.) Pers. flower buds and their efficacy against antimicrobial and anticancer activities. The UV-Visible spectrum was found at 413 nm showing a typical resonance spectrum for L. speciosa flower bud extract-assisted silver nanoparticles (Ls-AgNPs). Fourier transform infrared analysis revealed the presence of amines, halides, and halogen compounds, which were involved in the reduction and capping agent of AgNP formation. X-ray diffraction analysis revealed the face-centered cubic crystals of NPs. Energy dispersive X-ray verified the weight of 39.80% of silver (Ag), TEM analysis revealed the particles were spherical with a 10.27 to 62.5 nm range, and dynamic light scattering recorded the average particle size around 58.5 nm. Zeta potential showed a significant value at -39.4 mV, and finally, thermo-gravimetric analysis reported higher thermal stability of Ls-AgNPs. Further, the obtained Ls-AgNPs displayed good antimicrobial activity against clinical pathogens. In addition, a dose-dependent decrease in the anticancer activity by MTT assay on the osteosarcoma (MG-63) cell line showed a decrease in the cell viability with increasing in the concentration of Ls-AgNPs with an IC50 value of 37.57 µg/mL. Subsequently, an apoptotic/necrosis study was conducted with the help of Annexin-V/PI assay, and the results indicated a significant rise in early and late apoptosis cell populations. Therefore, green synthesized Ls-AgNPs were found to have potent antimicrobial and anticancer properties making them fascinating choices for future bio-medical implementations.

Оценка эквивалентной дозы излучения в режиме реального времени по данным спутника GOES

A system has been developed that makes it possible to evaluate the equivalent radiation dose at the altitudes of airliners in real time. A brief description of the calculation methodology is presented, a link is given to an information resource that provides data in the public domain. The result is shown for a typical spectrum of cosmic ray protons obtained from a satellite.

Structural and functional investigations of wall material extracted from banana peels

ABSTRACT The core objective of the current study was to extract heteroxylans from banana peel. Firstly, banana peels were dried to make fine powder, and their nutritional profile including moisture, crude fat, crude ash, crude protein, crude fiber, and nitrogen-free extract (NFE) was noted. Secondly, the heteroxylans were extracted from banana peels, and their bioactive profile was assessed, including total phenols and flavonoids contents, and their activity was assessed through commonly used antioxidant assays including DPPH, FRAP, and ABTS+. Heteroxylans were extracted through alkali extraction method, and their structural characterization was assessed through XRD and FTIR. The results showed that moisture content in banana peels were 60.73 ± 0.85% and 15.77 ± 0.33% in air dried and grounded banana peels, respectively, crude fat 3.94 ± 0.10%, crude protein 6.06 ± 0.15%, and NFE 48.13 ± 0.32%. The total dietary fiber of banana peel powder was 45.3 ± 0.45%, insoluble dietary fiber 34.23 ± 0.30%, and soluble dietary fiber 15.63 ± 0.25%. The bioactive profile of heteroxylans content in banana peels include TPC (19.83 ± 1.10 mg GAE/g), TFC (22.73 ± 0.90 mg QE/g), DPPH (40.73 ± 0.80 mg TE/g), FRAP (39.63 ± 0.73 mg TE/g), and ABTS+ (83.43 ± 0.70 (mg TE/g). The yield of extracted heteroxylans was 9.95 ± 0.17 g/100 g. Further, the structural characterization through XRD showed the amorphous nature of banana peels heteroxylans, and FTIR showed the typical spectra in which different functional groups were observed. Conclusively, the current study showed that banana peels’ heteroxylans has unique nutritional, bioactive, and structural profile and can be utilized for various industrial purposes to enhance technological and nutritional properties using as food additive and way toward the sustainability

Urinary tract infections including pyelonephritis

Urinary tract infections (UTIs) are among the most common bacterial infections. The clinical phenotypes of UTIs are heterogeneous, ranging from rather benign uncomplicated infections to complicated UTIs and pyelonephritis to severe urosepsis. There has been a sharp increase in the incidence of severe UTIs, whilst the incidence of sepsis in general is declining. The classifications of UTIs partially differ between clinical and regulatory claims. Experience has also been gained over the last few years to define the appropriate endpoints that are used in clinical studies. Above all, patient-centered evaluation strategies of the endpoints were developed, in order to be able to identify the advantages of new antibiotics compared to traditional antibiotics. The development of new antibiotics for UTIs is essential, since multidrug-resistant enterobacteria, which belong to the typical bacterial spectrum of UTIs, are frequently associated with mortality from infections. In recent years, several new antibiotics/combinations that are particularly effective against multi-resistant gram-negative pathogens have been investigated for the treatment of UTIs.

Study of proton and deuteron pickup reactions (d,3He), (d,4He) with 8He and 10Be radioactive beams at ACCULINNA-2 fragment separator

The extremely neutron-rich systems 7H, 6H were studied in the 2H(8He, 3He)7H and 2H(8He, 4He)6H proton and deuteron pickup reactions with a 26 AMeV secondary 8He beam produced at the new ACCULINNA-2 fragment separator. In addition, the same proton and deuteron pickup reactions were generated using the 42 AMeV 10Be beam, and the population of low-lying 9Li and 8Li states was measured in reactions 2H(10Be,3He)9Li and 2H(10Be,4He)8Li, respectively. The latter were used as reference measurements in order to check the setup calibration over the excitation energy of 7,6H and to determine the real experimental energy resolution which was compared with Monte Carlo calculations. The corresponding results obtained for the superheavy hydrogen systems 7H, 6H are presented and discussed. Typical excitation spectra of the 9Li and 8Li nuclei are also shown.

Dietary Fiber from Navel Orange Peel Prepared by Enzymatic and Ultrasound-Assisted Deep Eutectic Solvents: Physicochemical and Prebiotic Properties.

Dietary fiber (DF) was extracted from navel orange peel residue by enzyme (E-DF) and ultrasound-assisted deep eutectic solvent (US-DES-DF), and its physicochemical and prebiotic properties were characterized. Based on Fourier-transform infrared spectroscopy, all DF samples exhibited typical polysaccharide absorption spectra, indicating that DES could separate lignin while leaving the chemical structure of DF unchanged, yielding significantly higher extraction yields (76.69 ± 1.68%) compared to enzymatic methods (67.27 ± 0.13%). Moreover, ultrasound-assisted DES extraction improved the properties of navel orange DFs by significantly increasing the contents of soluble dietary fiber and total dietary fiber (3.29 ± 1.33% and 10.13 ± 0.78%, respectively), as well as a notable improvement in the values of water-holding capacity, oil-holding capacity, and water swelling capacity. US-DES-DF outperformed commercial citrus fiber in stimulating the proliferation of probiotic Bifidobacteria strains in vitro. Overall, ultrasound-assisted DES extraction exhibited potential as an industrial extraction method, and US-DES-DF could serve as a valuable functional food ingredient. These results provide a new perspective on the prebiotic properties of dietary fibers and the preparation process of prebiotics.

Backward THz Emission from Two-Color Laser Field-Induced Air Plasma Filament.

Two-color laser field-induced plasma filaments are efficient broadband terahertz (THz) sources with intense THz waves emitted mainly in the forward direction, and they have been investigated intensively. However, investigations on the backward emission from such THz sources are rather rare. In this paper, we theoretically and experimentally investigate the backward THz wave radiation from a two-color laser field-induced plasma filament. In theory, a linear dipole array model predicts that the proportion of the backward emitted THz wave decreases with the length of the plasma filament. In our experiment, we obtain the typical waveform and spectrum of the backward THz radiation from a plasma with a length of about 5 mm. The dependence of the peak THz electric field on the pump laser pulse energy indicates that the THz generation processes of the forward and backward THz waves are essentially the same. As the laser pulse energy changes, there is a peak timing shift in the THz waveform, implying a plasma position change caused by the nonlinear-focusing effect. Our demonstration may find applications in THz imaging and remote sensing. This work also contributes to a better understanding of the THz emission process from two-color laser-induced plasma filaments.

Disentangling the confounding spectroscopy of C1 molecules: Without symmetry as a guide, everything is allowed

The spectra of C1 molecules are confounding in that each of the fundamental vibrational modes transform as the same irreducible representation (A) and hence each band consists of a seemingly random distribution of a-, b-, and c-type transitions. This is in contrast to higher symmetry molecules for which band types are readily deduced by simple symmetry rules. Herein, we present a method to simulate the convoluted rotational contours in the gas-phase spectra of C1 molecules by combining existing ab initio calculations with Colin Western’s pgopher rotational contour program. Specifically, ab initio calculations in the NWChem suite of programs were employed to predict the components of the dipole moment derivatives along the principal axes of the moments of inertia. This information was then input into pgopher to model the fundamental band contours as a sum of a-, b-, and c-type transitions. This method was applied to simulate the rotational contour spectra of a series of representative C1 molecules which were then compared against both ab initio stick spectra and experimentally measured broadband IR spectra from the Pacific Northwest National Laboratory infrared gas-phase database. In addition to providing further insight beyond what is revealed in a typical stick spectrum, the simulated contours showed good agreement with the measured spectra.

Audible noise analysis of 750‐kV AC transmission line in high‐altitude area under different weather

AbstractIn order to build UHV AC transmission lines at high altitudes, it is necessary to analyze the audible noise (AN) characteristics of the existing EHV transmission lines at high‐altitude areas to guide the design. The typical test data of AN for 750‐kV single‐circuit transmission lines measured at the Guanting long‐term observation station, located at an altitude of 1854 m, were collected. Two methods of sorting the test data of AN and extracting valid data were given. Then the levels of AN under different weather conditions were analyzed, which showed that AN was raised with the increase of instantaneous rainfall and snowfall. Typical frequency spectrums of AN under different weather were also obtained, the pure tone at 100 Hz was more prominent under rainy and snowy weather, and the pure‐tone oscillation attenuated at different positions. The statistical results and the calculated difference of AN over 5.5 h with continuous rainfall were obtained. For the 750‐kV transmission line in the quiet plateau areas, the calculated difference between AN during rainy days and fair weather can be taken as 25 dB, and the calculated value of the altitude correction coefficient of 2.85 dB/1000 m is better consistent with the measured value.