Internal Structure Research Articles

Insight into three-dimensional structure of the lunar crust and upper mantle in the Mare Crisium from gravity imaging

Mare Crisium is a typical Mascon on the Moon, and a detailed 3-D structure of the lunar crust and upper mantle is essential to explore the causes of the lunar Mascon. However, research in the Mare Crisium region has focused more on surface rather than internal structure in the past few decades. With the development of space exploration technology, lunar gravity data have been applied several times to determine the internal structure of the Moon. Nevertheless, the gravity method has limitations in terms of vertical resolution. To address this issue, this paper adopts the wavelet multi-scale analysis method to decompose the gravity anomaly data in the Mare Crisium region. The power spectrum method is then used to estimate the mean source depth of the decomposed gravity anomaly signal. On the one hand, the gravity anomaly signal and its corresponding mean source depth at different scales can be used to stratify the structure of the lunar crust and upper mantle in the Mare Crisium region, and then obtain the density structure of each layer. On the other hand, the gravity anomaly signals from the crust-mantle undulations are extracted and combined with prior information to invert the depth of the crust-mantle interface in the Mare Crisium region. As a result, the 3-D structure of the lunar crust and upper mantle in the Mare Crisium region was obtained. The study indicates that there are two high-density bodies with a large range in the interior of Mare Crisium. The first high-density body is located in the western part of the Mare Crisium, and the centre of its bottom is about 54°E longitude and 17°N latitude. The second high-density body is located in the northeast of the Mare Crisium, and the centre of its base is about 63°E longitude and 25°N latitude. Additionally, the study found that the crust-mantle interface of the Mare Crisium is obviously uplifted, and the uplifting rebound phenomenon exists in the centre of the basin. Considering the depth and size of the high-density body, Mare Crisium probably experienced two high-angle, high-speed impacts at least.

Porous asphalt mixture performance in cold regions: Case study of Chicago

Porous Asphalt Mixtures (PAMs) improve resilience of flexible pavements in the context of climate change. PAM application in coastal cities like Chicago is of interest; however severe winters compromise the durability of PAMs given their susceptibility to freeze-thaw. This work aimed to evaluate the to-date experience with PAMs in Chicago, exploring benefits and limitations to be considered for future projects in the Southern Lake Michigan region. Full-depth PAM cores were obtained from seven sections, constructed in different years. Tests were conducted to assess the evolution of surface texture, internal structure, and multi-scale material properties. Regarding surface texture, consistent change over time was observed, such as loss of the “channel” structure, and increase in mean profile parameters because of raveling. Also, binder content varies with time within different layer depths. An aging gradient in terms of stiffness from top to bottom within the layer does not necessarily occur. However, binder ductility shows drastic and consistent reduction throughout the layer as aging increases. Analysis of internal structure using a CT scan revealed that there is also a lack of homogeneity in the air void and particle size distributions. Finally, this study suggests that full-depth PAM viscoelastic behavior is sensitive to saturation level, and this is a relevant subject to be considered, since partial saturation may be a condition often observed in the field.

Abnormal enrichment of Th and U in melanosome of migmatite in Jivumdnubanda, Eastern Dharwar Craton, India: A unique occurrence in the world

The Neoarchaean (∼2.7Ga) migmatite melanosome of Jivumdnubanda area comprises anomalous radioactive elemental concentration. Significant amount of Th (68.54-290.85ppm) and U (29.68-114.47ppm) is observed within biotite-rich melanosome as inclusions. Radioelements are concentrated in certain accessory minerals e.g., allanite, apatite, xenotime and zircon. Leucosomal counterparts are devoid of such higher radioactive elemental concentration, which makes the study significant because the incompatible elements as well as the accessory minerals tend to go into the melt phases more preferentially. Each component of migmatite e.g., melanosome, leucosome and the diatexites are studied in detail from outcrops, under an optical microscope and by geochemical analysis. Structural deformation aspects are also taken care along with granite age determination to link the diatexite with anatexis timing. It is found that the migmatites formed around a pressure of ∼600 MPa correspond to a ∼20-22 km crustal depth when the hydrous mineral breakdown led to ∼50% melting of evolved TTG protolith. Radiation-induced damage of the accessory minerals due to alpha decays destroyed the internal crystal structures at places. This metamictization and associated radiation damage of more or less refractory minerals along with deformation associated grain-scale fractures make easier to release mobile uranium during hydration and associated alteration at later stage. The presently observed radioactive elemental concentrations are the remnants left behind in the melanosome after leaching out of significant uranium.

Crucial role of SWL1 in chloroplast biogenesis and development in Arabidopsis thaliana.

The disruption of the SWL1 gene leads to a significant down regulation of chloroplast and secondary metabolites gene expression in Arabidopsis thaliana. And finally results in a dysfunction of chloroplast and plant growth. Although the development of the chloroplast has been a consistent focus of research, the corresponding regulatory mechanisms remain unidentified. In this study, the CRISPR/Cas9 system was used to mutate the SWL1 gene, resulting in albino cotyledons and variegated true leaf phenotype. Confocal microscopy and western blot of chloroplast protein fractions revealed that SWL1 localized in the chloroplast stroma. Electron microscopy indicated chloroplasts in the cotyledons of swl1 lack well-defined grana and internal membrane structures, and similar structures have been detected in the albino region of variegated true leaves. Transcriptome analysis revealed that down regulation of chloroplast and nuclear gene expression related to chloroplast, including light harvesting complexes, porphyrin, chlorophyll metabolism and carbon metabolism in the swl1 compared to wild-type plant. In addition, proteomic analysis combined with western blot analysis, showed that a significant decrease in chloroplast proteins of swl1. Furthermore, the expression of genes associated with secondary metabolites and growth hormones was also reduced, which may be attributed to SWL1 associated with absorption and fixation of inorganic carbon during chloroplast development. Together, the above findings provide valuable information to elucidate the exact function of SWL1 in chloroplast biogenesis and development.

Experimental study on the deterioration of mechanical properties of sandy mudstone under different water-gas interactions

Based on the water-rock-gas coupling test system, the work combined the scanning electron microscope and XTDIC 3D full-field strain measurement system. The Brazilian splitting test was performed on four groups of sandy mudstone specimens under contrast (CO), mash-gas soaking (MS), water-mash gas soaking (WM), and water-soaking (WS) conditions. The tensile strength, deformation failure, and microscopic characteristics of fractures were studied to reveal the deterioration mechanism of the tensile properties of sandy mudstone under water-gas coupling. The results showed that the uniaxial tensile strength of sandy mudstone specimens under the three soaking conditions was less than that of the contrast conditions. Compared with specimens in the CO group, the tensile strength of specimens in MS-WS groups was reduced; the WS group decreased the most. Specimens changed from brittle failure to plastic failure after soaking. The decrease rate in strength after the peak was consistent with the change trend in tensile strength. It led to a larger localized deformation zone of specimens and more obvious displacement. The deformation localization zone of the WS group was the broadest, with the most intense displacement. Besides, stress concentration first occurred in the submerged part of the WM group. Fractures expanded in the direction of maximum principal strain. The internal pore structure of sandy mudstone specimens in each group changed after soaking. The average porosity, maximum pore area, and probability entropy of specimens in WS-MS groups increased compared to the CO group. The WS group had the largest reduction and the MS group had the smallest. The pre-peak energy storage capacity of sandy mudstone specimens was gradually weakened. Compared with the CO group, that in the WS-MS groups was reduced. The WS group had the greatest reduction, and the MS group had the smallest. The deterioration effect of water on the interior of sandy mudstone was stronger than that of gas. The work is of great significance for understanding the stability of coal and rocks in closed-pit high-gas mines.

Investigation of forming process and deformation mechanisms of 3D warp interlock fabric

This article introduces a modeling method aimed at predicting the internal geometric structure of 3D warp interlock fabric. Inspired by the digital element method, the method employs truss elements to model the yarns as fiber bundles, and considers their material properties. This technique allows for predicting the microstructure of 3D woven fabric based on simple input characteristics. By varying the elastic modulus of virtual fibers, the friction coefficient between fibers, and the tension load at the ends of yarns, and designing compression molding molds to compress the fabric into shape, the virtual fiber fabric predicted the influence of variables on the fabric. The study found that the structure of the samples obtained through CT scanning is generally consistent with the structure of the virtual fiber fabric. The elastic modulus has a relatively minor impact on the fabric structure, whereas the friction coefficient and tension load significantly affect the cross-sectional shape of the yarns. During compression molding, deformation within the mold leads to interlayer fabric slippage and changes in the cross-sectional shape of the fabric. This suggests the feasibility and applicability of virtual simulation testing methods for analyzing the behavior of various types of 3D woven fabrics.

The Impact of Green Innovation on the Carbon Performance of Chinese Manufacturing Enterprises: Moderating Role of Internal Governance

With the increasing problems of global warming, ecological damage, and excessive consumption of resources, a greater number of countries are focusing on corporate carbon performance and carbon emissions. Enterprises can save energy and reduce emissions through green innovation, which will improve the efficiency of carbon use and contribute to higher levels of corporate carbon performance. Meanwhile, effective corporate governance can improve enterprise performance, while internal governance systems can affect enterprise carbon performance. This study aims to reveal how the green innovation affect carbon performance of enterprises and the role of internal governance. So this study utilizes the data of China's A-share listed manufacturing companies from 2010- 2020 to examine the impact of green innovation on corporate carbon performance through a fixed-effects model, and to examine the impact of corporate internal governance structure on green innovation and carbon performance through a moderating-effects model. The data used in this study are mainly from China Securities Market and Accounting Research Database (CSMAR) and China Research Data Service Platform (CNRDS), and the robustness test is conducted by replacing the independent variables using the 2sls method. The findings indicate that green innovation has a significant contribution to enterprise performance on carbon. Ownership concentration and executive political connections negatively moderated the relationship between green innovation and carbon performance. Director compensation positively moderates the relationship between green innovation and carbon performance. This research provides a theoretical groundwork for future studies on green innovation and carbon performance, and its findings are instructive for both the introduction of government policies and the restructuring of internal corporate governance.

Comparative morphology of male genitalia in antlions (Insecta, Neuroptera, Myrmeleontidae), with emphasis on owlflies (Ascalaphinae) and a possible structural evolutionary scenario.

Male genitalia morphology in Myrmeleontidae has traditionally been insufficiently studied, although it has received increased attention for its diagnostic value in recent times. A neutral terminology has generally been applied in standard taxonomic practice, yet knowledge of an equivalent and stable terminology across taxa based on comparative morphology has been missing. Herein a detailed comparative morphology study with examples from most tribes within Myrmeleontidae, including owlflies (Ascalaphinae), attempts to relate external and internal genital structures based on a proposed groundplan for Neuroptera and Myrmeleontidae. We contend that a groundplan based on 10 abdominal segments, plus vestigial structures from an 11th segment, coherently depicts structural components across myrmeleontid taxa. A gonarcus, an element of Neuropterida amply referred in Neuroptera, is supported to represent the pair of abdominal appendages of segment X medially fused, with gonocoxite and gonostylus components. In most myrmeleontid taxa, basal (gonocoxites) and distal (gonostyli) components separate, with gonostyli positioned posteriorly with respect to gonocoxites, still united with translucent, lightly sclerotized tissue, forming a more or less conical structure, a proposed synapomorphy for the family. Ninth gonostyli are generally reduced (pulvini) and have migrated close to the base of gonarcus (10th gonocoxites). A pelta, also a potential synapomorphy for Myrmeleontidae, derives from paired setose surfaces of the 10th gonostyli, medially positioned (still evident in Bubopsis). Three structural types of gonarcus are diagnosed for illustrative purposes, as they may represent convergent constructs.

Potential contributions of digital finance to alleviating the ‘low-end lock-in’ dilemma for green innovation in enterprises

As climate change risks intensify worldwide, green technological innovation by enterprises has become a crucial factor affecting the balance between economic development and ecological governance. This paper utilizes data from Chinese A-share listed companies in heavily polluting industries from 2011 to 2021 to investigate the impact and mechanism of the knowledge spillover effect of enterprise digital finance development on the phenomenon of ‘low-end lock-in’ in green innovation. The study finds that digital finance development significantly promotes green innovation in enterprises, with a more pronounced enhancement in high-end green innovation output, thereby mitigating the phenomenon of ‘low-end lock-in’ in green innovation. Mechanism analysis reveals that the development of digital finance in enterprises facilitates high-end green innovation by alleviating financing constraints and enhancing internal control levels through internal and external governance structures. Heterogeneity tests indicate that the promotion effect of digital finance development on high-end green innovation is more pronounced in samples of state-owned enterprises, large and medium-sized enterprises, and enterprises in central and eastern regions. This paper constructs an index of digital finance development for enterprises through text analysis, providing theoretical support for micro-enterprise research on digital finance development and empirical support for the impact of financial development trends on theories of enterprise green innovation.

Simulation-based design of 1-D copper nanograting device for sensing application by studying electromagnetic properties on Cu/Air interface

Sensing devices has been an interesting area of study because of their immense application in practical life. In the present work, the extraordinary optical transmission (EOT) along with surface plasmon polaritons (SPPs) excitation at the metal/ dielectric interface is investigated RF-module of COMSOL Multiphysics 5.3a has been used to investigate copper (Cu) nanograting structure on the glass substrate in periodic arrangement of 1-dimensional (1D). The visible-infrared electromagnetic wavelength of 400–900 nm has been used to excite the SPPs at the interface and a light port is provided from the substrate side. The optimum EOT has been investigated at transmission spectra of 0th order. During this process thickness of the slit is fixed at 50 nm, the periodicity of the unit cell is fixed at 700 nm, and the width of the slit changed to check its effect on the EOT. Additionally, phenomena of near field investigation have also used to explore the transmission-based performance of field at thespecificboundary of copper (Cu) and airwhich confirm spectraoutcomesof transmission thorough the fabricated device. The optimum value of EOT foundwhenthe width of slit isat250 nm for the Cu/air interface.The deviceused for this purpose is modeled in COMSOL. Along the EOT the SPPs phenomena is also investigated by using present modeled device.These phenomena are observed by studying the electric and magnetic parts of the device that models the Cu/Air interface. We tested it with different slit widths ranging from 50-450 nm. The coupling efficiency and sensitivity of Cu/Air 1D device design at optimum slit width of 250 nm calculated. Such devices are increasingly applicable in bio photonics sensing of DNA structure, in vivo study of the internal structure of the body, imaging, surface chemical reaction, environmental remediation, and in various solar cell industries (plasmonic solar cell).

Effect of weak alkaline electrolyzed water on rice cooking: Promoting rapid water absorption and enhancing the quality and digestibility

Promoting the rapid water absorption of rice is beneficial for increasing the cooking quality and digestibility of rice. Under the action of an electric field, weak alkaline electrolyzed water (WAEW) had a smaller cluster system compared to tap water, with a 17.30% decrease in DDAA-OH (double donor-double acceptor) and a 22.89% increase in Free-OH. Therefore, there were fewer hydrogen bonds formed between water molecules, resulting in more free proton donors and proton acceptors, which increased the possibility of forming more hydrogen bonds with other substances. During the soaking process, WAEW could effectively increase the water absorption rate, maximum water content, and water diffusion rate in different types of rice. As WAEW formed more hydrogen bonds with substances in the rice, it was easier to combine with substances in the rice, forming more bound water. Under the combined effect of the alkaline environment of WAEW and the characteristics of its own water molecules, the surface and internal structure of the rice were eroded, the surface layer was peeled off, and a large number of pore structures were formed. Along with the increased water absorption, more substances such as starch and protein dissolved from the rice. The cooked rice soaked in WAEW had greater sensory quality, higher digestibility and glycemic index. Therefore, WAEW could be used as a new method for cooking rice, promoting the rapid absorption of water and increasing the sensory quality and digestibility.

Effect of assisted drying methods on the microstructure and related quality attributes of fried chicken nuggets.

The potential for reducing oil uptake by applying aided pre-drying techniques (microwave, infrared, and convective hot air) was studied on chicken nuggets. Convective hot air (60, 80, and 100°C); microwave (20, 40, and 60 W); and infrared (150, 250, and 400 W) drying techniques were used to pre-treat chicken nuggets between 1 and 11 min based on preliminary study before frying at 170°C for 3 min. Standard laboratory methods were employed to assess the quality attributes of fried chicken nuggets, including oil and moisture content, colour, and texture. By comparing the micrographs obtained from chicken nuggets pre-dried using the three pre-dried methods (Microwave, conventional hot air and infra-red), chicken nugget pre-dried using microwave at 60 W have lesser oil cracks (18.05%) when compared to the rest pre-dried method.Pre-drying substantially lowers moisture content, with microwave pre-drying being most effective, particularly at higher power levels (19.38±1.36 - 43.11±0.10). Microwave pre-drying densifies the nugget structure, reducing oil absorption during frying (13.15±0.13- 28.38±0.12). Microscopic examination of chicken nuggets pre-dried using three methods (microwave, conventional hot air, and infra-red) reveals that those pre-dried with a microwave at 60 W exhibit fewer oil cracks (18.05%) compared to the other pre-drying methods. It also affects (p<0.05) the nugget colour, with higher power levels and longer drying times resulting in a darker (10.12±0.01-25.29±0.15) and less yellow nuggets. Texture is also significantly (p<0.05) affected, with higher power levels and longer drying times leading to increased hardness and chewiness (158.20±1.49-438.14±1.89; 88.00 ± 0.93- 165.79 ± 0.86; 96.20 ± 1.44 - 210.60 ± 0.45; ). Based on the findings, microwave pre-drying at 60W for 11 minutes is recommended for achieving low oil content while maintaining good internal structure in fried chicken nuggets

Research Progress on Key Mechanical Components of the Pneumatic Centralized Fertilizer Discharge System

The pneumatic centralized fertilizer discharge system is an important part of pneumatic fertilization machinery and mainly includes a fertilizer discharge device, an air–fertilizer mixing device and a pneumatic distribution device. In this paper, the mechanical structure, key parameters and research methods of pneumatic centralized discharge devices, air–fertilizer mixing devices and pneumatic distribution devices at home and abroad are briefly analyzed. The advantages and disadvantages of these existing devices are summarized, the existing problems are discussed and improvement methods are put forward. In this paper, the structural adaptability, uniformity and stability of the fertilizer discharge of different types of fertilizer discharge devices, such as external groove wheel types, spiral types and centrifugal types, are comprehensively analyzed. The working principle of air–fertilizer mixing devices using the Venturi effect to achieve the uniform mixing of fertilizer and airflow is expounded. The effects of air–fertilizer mixing devices with different structural forms and parameters on mixing performance and the motion characteristics of air–solid two-phase flows are analyzed. The influence of the internal structure, key parameters and distribution mode of pneumatic distribution devices on the uniformity and accuracy of fertilizer distribution are analyzed. This paper focuses on how to improve the uniformity, stability and consistency of discharge across rows provided by the pneumatic centralized fertilizer discharge system. The research status and progress made regarding the core components of the pneumatic centralized fertilizer discharge system at home and abroad are summarized. Based on different research results, the key factors and methods for improving the uniformity of fertilizer discharge are discussed.

Product manifold optimization-based joint beamforming for RIS-aided MIMO systems: A fairness based approach

Reconfigurable intelligent Surface (RIS) can effectively improve the communication quality and extend the signal coverage range by reconfiguring the wireless communication transmission environment, which is very suitable for millimeter wave (mmWave) multiple-input multiple-output (MIMO) systems. In this paper, a product manifold optimization-based beamforming design (PMO-BD) algorithm for a RIS-assisted multi-user MIMO system is proposed to enhance fairness among users. We establish a lower bound for the minimum signal-to-interference-plus-noise ratio (SINR) among users as the optimization objective, which is subjected to multiple constraints. By maximizing the lower bound to ensure the quality of service (QoS) for each user, fairness among users get improved. The PMO-BD algorithm exploits the internal structure of the product manifold to deal with the high dimension and nonlinear characteristics of the problem effectively, thereby reducing algorithm complexity and enhancing convergence rates. Simulation results verify the advantages of the proposed PMO-BD algorithm in comparison to other algorithms.

Heat transfer characteristics of non-uniform channels flat heat pipe with micro pillar arrays and its application in power battery cooling

Heat pipe is a promising technology that can be applied to power batteries. However, it is associated with the challenge of countercurrent flow in gas–liquid two-phase working fluid. For this, this work proposes a non-uniform channels flat heat pipe with micro pillar arrays to form the internal “unidirectional flow”. The feasibility of such a strategy in alleviating the heat pipe burning dry is experimentally analyzed, along with the synergistic strengthening mechanism. Effects of heat pipe internal structures and micro pillar arrays area on thermal resistance and thermal conductivity are discussed. It is found that the maximum thermal conductivity of the optimized heat pipe could reach 3749.53 W·m−1·℃-1. On this basis, a battery cooling system coupled with the new heat pipe and localized serpentine passage cooling plate is then developed. The performance of the module is numerically evaluated by optimizing the key parameters including the passage height and operating conditions. It is shown that the system can control the average temperature of the battery pack within 27℃ at the end of 3C discharge with a coolant flow rate of 2 L/min and a channel structure of 7 mm × 7 layers. The maximum temperature difference between cells during the whole process is only 3.8℃.

Expert consensus on the application of critical care ultrasonography in invasive procedures

The evolution of critical care medicine is inextricably linked to the development of critical care procedures. These procedures not only facilitate diagnosis and treatment of critically ill patients, but also provide valuable insights into disease pathophysiology. While critical care interventions offer undeniable benefits, the potential for iatrogenic complications necessitates careful consideration. The recent surge in critical care ultrasound (US) utilization is a testament to its unique advantages: non-invasiveness, real-time bedside availability, direct visualization of internal structures, elimination of ionizing radiation exposure, repeatability, and relative ease of learning. Recognizing the need to optimize procedures and minimize complications, critical care utrasound study group of Beijing critical care ultrasound research assocition convened a panel of critical care experts to generate this consensus statement. This document serves as a guide for healthcare providers, aiming to ensure patient safety and best practices in critical care.

Improved Magnetic Resonance Image Reconstruction using Compressed Sensing and Adaptive Multi Extreme Particle Swarm Optimization Algorithm

One powerful technique that can offer a thorough examination of the body's internal structure is magnetic resonance imaging (MRI). MRI's lengthy acquisition times, however, may restrict its clinical usefulness, particularly in situations where time is of the essence. Compressed sensing (CS) has emerged as a potentially useful method for cutting down on MRI acquisition times; nevertheless, the effectiveness of CS-MRI is dependent on the selection of the sparsity-promoting algorithm and sampling scheme. This research paper presents a novel method based on adaptive multi-extreme particle swarm optimization (AMEPSO) and dual tree complex wavelet transform (DTCWT) for fast image acquisition in magnetic resonance. The method uses AMEPSO in order to maximize the sampling pattern and minimize reconstruction error, while also exploiting the sparsity of MR images in the DTCWT domain to improve directional selectivity and shift invariance. MATLAB software was used for simulation of the proposed method. In comparison with the particle swarm optimized-DTCWT (PSODTCWT) and DTCWT algorithms, respectively, the results demonstrated an improvement in the peak signal-to-noise ratio of 8.92% and 15.92% and a higher structural similarity index measure of 3.69% and 7.5%. Based on these improvements, the proposed method could potentially make high-quality, real-time MRI imaging possible, which might improve detection and treatment of medical conditions and increase the throughput of MRI machines.

Drone-based monitoring of intertidal blue mussel beds in the Wadden Sea – comparison of a threshold and two machine learning approaches

In the Wadden Sea, intertidal mussel beds of the blue mussel (Mytilus edulis) and the Pacific oyster (Magallana gigas) form distinct epibenthic communities and local hotspots of high biomass and biodiversity. To detect and evaluate natural and anthropogenic processes, a ground-based monitoring program started over 25 years ago in the German Wadden Sea. In this study, we describe the potential of drones and machine learning approaches for a remote sensing-based integration into an existing monitoring program of intertidal mussel beds. A fixed wing drone was used to cover an area of up to 39ha in a single flight, with an overall time saving potential of 50%. Applying machine learning approaches, a detailed extraction of the intertidal blue mussel bed coverage with an overall accuracy (OA) up to 95.6% was reached, applying a Support Vector Machine (SVM). The application of a multispectral sensor improved the classification performance. Compared to ground-based monitoring, the drone-based method provided significantly more information on the area extension, coverage, and associated algae of the mussel beds. The results show that drones can provide a non-invasive way to survey large and difficult to access areas providing detailed maps of mussel beds and their internal structures.

PSYCHOMETRIC EVIDENCE OF A MEASURE OF GENERAL SELF-EFFICACY IN PERUVIAN SCHOOLCHILDREN: INTERNAL STRUCTURE, RELIABILITY AND FACTORIAL INVARIANCE AND PROPOSAL OF A BRIEF VERSION

The present research aims to propose a brief version of a measure of general self-efficacy, based on the Self-Efficacy Scale, and to evaluate its evidence of validity based on internal structure, reliability and factorial invariance according to sex. A total of 806 students (67.5% male and 32.5% female) of secondary level from 13 educational institutions in the city of Arequipa (Peru) participated. The data were processed using Confirmatory Factor Analysis and Item Response Theory. The results indicate that the original 20-item version of the 10-item Brief Alegre Self-Efficacy Scale is unidimensional with adequate goodness-of-fit and reliability indices (ω= .89). In addition, the presence of factorial invariance between males and females was tested. It is concluded that the proposed measure is valid and reliable, with a monotonic level of difficulty. However, more research is needed with representative samples and with respect to other educational variables. 

Terahertz fan-beam computed tomography.

A terahertz (THz) fan-beam computed tomography (CT) system using a 0.3 THz continuous-wave sheet beam is proposed. The diffraction-free sheet beam expands in a fan shape in only one direction and provides propagation-invariant focal lines and extended the depth-of-field. The fan-beam CT based on this beam is the second-generation THz CT. It breaks the conventional 4-f symmetric structure of THz CT using the parallel beam. The fan-beam THz CT allows for use with a linear array detector, which reduces the time required to collect data. To demonstrate its feasibility for three-dimensional (3D) imaging, the 3D structure of a metal rod packed in a carton is reconstructed with the support of the system. The results show that the object's internal structure can be obtained by this new THz CT system while retaining the geometrically magnified features of the cross-sectional structure. The results of our research provide a template for the second-generation THz CT system, which provides an additional method for nondestructive testing.