Focal Properties Research Articles

Croatian catalogue and database of focal mechanism solutions, characteristic mechanisms, and stress field properties in the Dinarides and the surrounding regions

This report presents the CroFMS catalogue and database of focal mechanism solutions (FMS). It is based on the first-motion polarity data for earthquakes in Croatia and the neighbouring regions, collected over last four decades. The current catalogue version contains FMS for 410 earthquakes that were computed consistently, using the same programs, velocity models, and sets of parameters. Its content is described in terms of distributions of the time and origin of polarity picks, magnitudes, epicentral distances of stations, the quality marks, the phases used, azimuthal gap and distance to the closest station. It was also shown that solutions from the CroFMS catalogue and those independently obtained from the moment tensor inversions are generally consistent.Comparison of observed FMS with the latest European model of active fault sources (EFSM20) revealed several inconsistencies, most notably in the Zagreb and Petrinja epicentral areas, the greater Rijeka region, the Central Adriatic archipelago, and in the zone of surface traces of the thrust fronts of the East-Bosnian–Durmitor and Drina–Ivanjica nappes in Bosnia and Herzegovina.Spatial averaging of FMS over the whole study area produced maps of characteristic focal mechanisms, which may be found useful in the seismic hazard assessment in the areas where active faults are not identified or characterised.A formal stress inversion of the focal mechanism solutions produced a map of maximum horizontal stress orientations across the study area, revealing localized lateral variations that had not been identified in previous studies.

Ion optical design of the magnetic proton recoil neutron spectrometer for the SPARC tokamak.

A magnetic proton recoil (MPR) neutron spectrometer is being designed for SPARC, a high magnetic field (BT = 12T), compact (R0 = 1.85m, a = 0.57m) tokamak currently under construction in Devens, MA, USA. MPR neutron spectrometers are versatile tools for making high fidelity abinitio calibrated measurements of fusion neutron flux spectra and have been used to infer fusion power, ion temperature, fuel ion ratio, and suprathermal fuel populations at several high performance fusion experiments. The performance of an MPR neutron spectrometer is in large part determined by the design of the magnetic field, which disperses and focuses recoil protons. This article details the ion optical design of a high-resolution MPR neutron spectrometer, including the amelioration of image aberrations due to nonlinear effects. An optimized design is presented that achieves ion optical energy resolution δE/E < 1% and focal plane properties that enable straightforward integration with the hodoscope detector array.

Enhanced slit methodology for characterization of x‐ray focal properties

AbstractThe measurement of focal spot sizes in industrial x‐ray tubes using conventional edge and slit methods typically requires complex slit diaphragms and auxiliary testing equipment. Additionally, stringent spatial‐positioning requirements are imposed on the x‐ray tube, auxiliary testing equipment, and detector, making the machining of auxiliary testing equipment and meeting test conditions challenging. This study optimized and improved the auxiliary testing equipment and computations in the slit method based on the principles of the edge method. An experimental setup capable of self‐calibrating the spatial positions was designed, avoiding measurement errors during focal‐spot‐size measurements. We derived a formula for the focal spot size for this experimental setup, allowing measurements using slits of various sizes. Furthermore, we proposed a method for determining the focal spot size through linear fitting of multiple sets of slit dimensions and projected widths of the focal spot on the detector. This approach filters out random noise and errors during data collection, significantly enhancing measurement precision. By adjusting the slit and detector angles, we could measure the focal spot sizes at various angles and draw contour maps of the focal spot shape. This method was applied to measure the focal spot size and shape of a side‐window x‐ray tube under different voltage conditions. The overall measurement error was less than 6%, reflecting the reliability, accuracy, and consistency of the results obtained using the proposed method. Thus, the proposed method supports the inspection, verification, and maintenance of x‐ray sources.

Development of high energy resolution crystal analyzers based on microporous ceramics for resonant inelastic x‐ray scattering program at High Energy Photon Source

AbstractThe spherically bent x‐ray crystal analyzer is one of the key optical elements for performing high energy resolution hard x‐ray spectroscopies based on Rowland circle geometry. To meet the requirements of Resonant Inelastic X‐ray Scattering (RIXS) program at High Energy Photon Source (HEPS), the fourth‐generation high energy synchrotron in Beijing, China, high energy resolution crystal analyzers were fabricated. The fabrication processes of vacuum‐mounted flat‐diced crystal analyzers using home‐designed devices with microporous ceramics are presented. The energy resolution of the vacuum‐mounted crystal analyzers, for measuring Cu K‐edge RIXS, is benchmarked with that of the glued flat‐diced crystal analyzers. Both the gluing and vacuum‐mounting are proven to be reliable techniques for the routine production of spherical bent diced crystal analyzers with energy resolution of tens of meV, and with good focal properties and efficiency. In particular, the vacuum‐mounted technique will be beneficial for the RIXS techniques to target multiple elements of interest.

Extracellular matrix regulation of cell spheroid invasion in a 3D bioprinted solid tumor-on-a-chip

Tumor organoids and tumors-on-chips can be built by placing patient-derived cells within an engineered extracellular matrix (ECM) for personalized medicine. The engineered ECM influences the tumor response, and understanding the ECM-tumor relationship accelerates translating tumors-on-chips into drug discovery and development. In this work, we tuned the physical and structural characteristics of ECM in a 3D bioprinted soft-tissue sarcoma microtissue. We formed cell spheroids at a controlled size and encapsulated them into our gelatin methacryloyl (GelMA)-based bioink to make perfusable hydrogel-based microfluidic chips. We then demonstrated the scalability and customization flexibility of our hydrogel-based chip via engineering tools. A multiscale physical and structural data analysis suggested a relationship between cell invasion response and bioink characteristics. Tumor cell invasive behavior and focal adhesion properties were observed in response to varying polymer network densities of the GelMA-based bioink. Immunostaining assays and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) helped assess the bioactivity of the microtissue and measure the cell invasion. The RT-qPCR data showed higher expressions of HIF-1α, CD44, and MMP2 genes in a lower polymer density, highlighting the correlation between bioink structural porosity, ECM stiffness, and tumor spheroid response. This work is the first step in modeling STS tumor invasiveness in hydrogel-based microfluidic chips. Statement of significanceWe optimized an engineering protocol for making tumor spheroids at a controlled size, embedding spheroids into a gelatin-based matrix, and constructing a perfusable microfluidic device. A higher tumor invasion was observed in a low-stiffness matrix than a high-stiffness matrix. The physical characterizations revealed how the stiffness is controlled by the density of polymer chain networks and porosity. The biological assays revealed how the structural properties of the gelatin matrix and hypoxia in tumor progression impact cell invasion. This work can contribute to personalized medicine by making more effective, tailored cancer models.

Advanced MRI techniques in abdominal imaging.

Magnetic resonance imaging (MRI) is a crucial modality for abdominal imaging evaluation of focal lesions and tissue properties. However, several obstacles, such as prolonged scan times, limitations in patients' breath-hold capacity, and contrast agent-associated artifacts, remain in abdominal MR images. Recent techniques, including parallel imaging, three-dimensional acquisition, compressed sensing, and deep learning, have been developed to reduce the scan time while ensuring acceptable image quality or to achieve higher resolution without extending the scan duration. Quantitative measurements using MRI techniques enable the noninvasive evaluation of specific materials. A comprehensive understanding of these advanced techniques is essential for accurate interpretation of MRI sequences. Herein, we therefore review advanced abdominal MRI techniques.

Bio‐Engineering Yeast Cells Biolenses by Reshaping Intracellular Vacuoles

AbstractAn intriguing field of research has recently emerged in which biological cells can be demonstrated to behave as photonics devices, such as optical microlenses. This research highlights yeast cells as promising candidates for engineering biolenses with customizable focal properties. Typically serving as positive biolenses due to their quasi‐spherical shape and positive refractive index (RI) contrast, yeast cells can achieve a negative lensing effect by manipulating their intracellular content, without altering their overall morphology. In fact, it shows that exposure to hypotonic conditions induces the formation of a large, roundish vacuole with lower RI values with respect to the surrounding cytoplasm, thus altering the cell's optical properties. This behavior is investigated by using 3D RI tomograms obtained through a holo‐tomographic phase imaging flow cytometry system, demonstrating that the anisotropic nature of yeast cells results in focal properties dependent on their specific orientations in respect to the incident light. Furthermore, Zemax OpticStudio is utilized to perform comprehensive assessments for optical design analysis of the obtained cell biolenses. The methods described here and the related results represent a pioneering investigation of biological cells’ metamorphoses via intracellular content manipulation for biolens applications.

The effect of Air Gap Width on the Focal Properties of Objective Snorkel Lens

The current research dealt with studying the effect of air gap width on the objective properties of the magnetic Snorkel lens used in the scanning electron microscope. The structure of the lens was designed and its properties were studied, and the axial magnetic flux density distribution was calculated (Bz) using the electron optical design program (EOD), The results indicated that the maximum value of the magnetic flux density (Bmax) increased with a decrease in the width of the air gap (S), accompanied by a decrease in the half-width, spherical and chromatic aberrations, and an increase in the resolution of the analysis.

Características epidemiológicas e fatores de risco em propriedades foco de anemia infecciosa equina no Estado do Rio Grande do Sul, Brasil

Abstract In Brazil, equine infectious anemia (EIA) infection is widespread in various regions, with variable prevalence levels. The objective of this work was to determine the epidemiological characteristics that could contribute to its dissemination on the western border of Rio Grande do Sul, Brazil. To accomplish this, an epidemiological questionnaire was administered to equine owners who had experienced EIA-positive animals on their properties from 2009 to 2019. The interviewees were contacted via phone calls, and the questions aimed to identify patterns among properties, on animal management, health, and owner’s knowledge about the infection. The primary information was acquired from the data of the Official Veterinary Service (OVS) through data compilation and tabulation of the official forms. Additionally, the same questionnaire was applied to properties without records of the infection, as control. The results were analyzed using forward logistic regression to explore potential risk associations. Out of a total of 123 focal properties, 28 interviews were completed, six were interrupted or declined, 55 did not respond to phone calls, and 34 had outdated contact information. Among the 30 control properties, 15 agreed to participate in the survey. The results suggest that breeding, management, and sanitary control practices are Similar between focal and control properties. Only two related risk factors could be distinguished for properties that have never engaged in these practices, which were animal transit outside the property and contact with other horses. In addition, it was observed that the official register is outdated for a significant number of properties.

Epidemiological characteristics and risk factors in focal properties of equine infectious anemia in Rio Grande do Sul State, Brazil

Resumo No Brasil, a infeção por anemia infecciosa equina (AIE) está disseminada por diversas regiões, com níveis de prevalência variáveis. O objetivo deste trabalho foi determinar as características epidemiológicas que poderiam contribuir para a disseminação da AIE na região oeste do Rio Grande do Sul, Brasil. Para isso, foi aplicado um questionário epidemiológico aos proprietários de equinos que tiveram animais positivos para AIE em suas propriedades no período de 2009 a 2019. Os entrevistados foram contatados por meio de ligações telefônicas, e as perguntas visavam identificar padrões entre as propriedades, sobre o manejo dos animais, a sanidade e o conhecimento do proprietário sobre a infeção. As informações primárias foram obtidas nos arquivos do Serviço Veterinário Oficial (SVO), compiladas e tabuladas. Adicionalmente, o mesmo questionário foi aplicado a propriedades sem registo de infeção, designadas controle. Os resultados foram analisados por meio de regressão logística forward para explorar potenciais associações de risco. De um total de 123 propriedades focais, 28 entrevistas foram completadas, seis foram interrompidas ou recusadas, 55 não responderam aos telefonemas e 34 tinham informação de contato desatualizada. Entre as 30 propriedades controle, 15 concordaram em participar do inquérito. Os resultados sugerem que as práticas de criação, gestão e controle sanitário são semelhantes entre as propriedades foco e as controle. Apenas dois fatores de risco puderam ser distinguidos das propriedades positivas e negativas, sendo estes o trânsito de animais da propriedade e o contato com outros cavalos. Além disso, observou-se que os registos oficiais dos produtores está desatualizado para um número significativo de propriedades.

Illusory optical defocus generated by shaded surface texture

The human visual system is tasked with the problem of extracting information about the world from images that contain a conflated mixture of environmental sources and optical artifacts generated by the focal properties of our eyes. In most contexts, our brains manage to distinguish these sources, but this is not always the case. Recent work showed that shading gradients generated by smooth three-dimensional (3D) surfaces can elicit strong illusory percepts of optical defocus1,2 - the perception of illusory blur is only eliminated when the surface appears attached to self-occluding contours3, surface discontinuities1, or sharp specular reflections1,2, which all generate sharp ('high spatial frequency') image structure. This suggests that it should also be possible to eliminate the illusory blur elicited by shaded surfaces by altering the surface geometry to include small-scale surface relief, which would also generate high-frequency image structure. We report the surprising result here that this manipulation fails to eliminate the perception of blur; the fine texture fails to perceptually 'bind' to the low-frequency image structure when there is a sufficient gap between the spatial scales of the fine and coarse surface structure. These findings suggest that discontinuous 'gaps' in the spatial scale of textures are a segmentation cue the visual system uses to extract multiple causes of image structure.

High-efficiency metalenses for zone-plate-array lithography

To date, zone-plate-array lithography has employed an array of binary pi-phase zone plates, each 135 μm in diameter, operating at 405 nm wavelength, in conjunction with a spatial-light modulator and a moving stage, to expose large-area patterns in photoresist without a mask. Although the low focal efficiency (&amp;lt;34%) and high background (&amp;gt;66%) of such zone plates can be mitigated via proximity-effect correction, increased focal efficiency would enable higher quality patterning. To that end, we have designed flat, diffractive-optical “metalenses.” Each is first divided into Fresnel zones, across which the effective index-of-refraction is modulated by forming appropriate pillars or holes such that diffracted beams interfere constructively at the focal spot, located 100 μm in front of the lens plane. The diffraction efficiency of each zone is simulated using rigorous-coupled-wave analysis. A genetic algorithm is then used to determine if higher efficiency can be achieved by repositioning of the pillars or modifying their widths. MEEP software is used to predict focal efficiency of the completed metalens design. Scanning-electron-beam lithography was used to fabricate effective-index-modulated metalenses in CSAR-62 e-beam resist. In some cases, the focal properties and efficiencies of such structures were measured, yielding focal efficiencies up to 54%. In other cases, the e-beam-written pattern was transferred into a spin-on hard mask and then into an organic dielectric of 1.9 index of refraction using reactive ion etching. Focal efficiencies up to 69% are predicted for such structures, a significant improvement over the binary pi-phase zone plates used previously.

Gun‐ownership disclosure and localized home prices

AbstractThis article examines how the disclosure of local gun‐ownership information affects property values. Using the sudden disclosure of a gun‐ownership map in two New York counties, we explore how home sellers respond to this exogenous information shock. Our results show that an additional permit holder in the neighborhood leads to a 1% decrease in housing prices after the disclosure. This effect is highly localized in that property values are only negatively impacted by gun‐permit holders within 0.1 mi of the focal property. These findings highlight the negative effect of the disclosure of gun‐ownership information on localized home prices.

Radially polarized beams' phase filtering focal properties based on path integral analysis.

This paper introduces the path integral (PI) to the analysis of radially polarized (RP) beams' tight focusing problem. The PI makes the contribution of each incident ray on the focal region visible and then makes it possible to choose the filter's parameters more intuitively and precisely. Based on the PI, a zero point construction (ZPC) phase filtering method is realized intuitively. With ZPC, the focal properties of RP solid and annular beams before and after filtering were analyzed. The results show that the combination of a large NA annular beam and phase filtering can result in superior focus properties.

Rbpj Deficiency Disrupts Vascular Remodeling via Abnormal Apelin and Cdc42 (Cell Division Cycle 42) Activity in Brain Arteriovenous Malformation.

Brain arteriovenous malformations (bAVM) are characterized by enlarged blood vessels, which direct blood through arteriovenous shunts, bypassing the artery-capillary-vein network and disrupting blood flow. Clinically, bAVM treatments are invasive and not routinely applicable. There is critical need to understand mechanisms of bAVM pathologies and develop pharmacological therapies. We used an in vivo mouse model of Rbpj-mediated bAVM, which develops pathologies in the early postnatal period and an siRNA in vitro system to knockdown RBPJ in human brain microvascular endothelial cells (ECs). To understand molecular events regulated by endothelial Rbpj, we conducted RNA-Seq and chromatin immunoprecipitation-Seq analyses from isolated brain ECs. Rbpj-deficient (mutant) brain ECs acquired abnormally rounded shape (with no change to cell area), altered basement membrane dynamics, and increased endothelial cell density along arteriovenous shunts, compared to controls, suggesting impaired remodeling of neonatal brain vasculature. Consistent with impaired endothelial cell dynamics, we found increased Cdc42 (cell division cycle 42) activity in isolated mutant ECs, suggesting that Rbpj regulates small GTPase (guanosine triphosphate hydrolase)-mediated cellular functions in brain ECs. siRNA-treated, RBPJ-deficient human brain ECs displayed increased Cdc42 activity, disrupted cell polarity and focal adhesion properties, and impaired migration in vitro. RNA-Seq analysis from isolated brain ECs identified differentially expressed genes in mutants, including Apelin, which encodes a ligand for G protein-coupled receptor signaling known to influence small GTPase activity. Chromatin immunoprecipitation-Seq analysis revealed chromatin loci occupied by Rbpj in brain ECs that corresponded to G-protein and Apelin signaling molecules. In vivo administration of a competitive peptide antagonist against the Apelin receptor (Aplnr/Apj) attenuated Cdc42 activity and restored endothelial cell morphology and arteriovenous connection diameter in Rbpj-mutant brain vessels. Our data suggest that endothelial Rbpj promotes rearrangement of brain ECs during cerebrovascular remodeling, through Apelin/Apj-mediated small GTPase activity, and prevents bAVM. By inhibiting Apelin/Apj signaling in vivo, we demonstrated pharmacological prevention of Rbpj-mediated bAVM.

TEMGYM Advanced – NanoMi lens characterisation

A complete analysis including finite element method (FEM) calculation, focal length properties, and thirdorder geometric aberrations of the open-source electrostatic lens from the NanoMi project is presented. The analysis is carried out by the software TEMGYM Advanced, a free package developed to carry out ray-tracing and lens characterisation in Python. Previously TEMGYM Advanced has shown how to analyse the aberrations of analytical lens fields; this paper expands upon this work to demonstrate how to apply a suitable fitting method to discrete lens fields obtained via FEM methods so that the aberrations of real lens designs can be calculated. Each software platform used in this paper is freely available in the community and creates a free and viable alternative to commercial lens design packages.

The effects of ecology and behavior on the evolution of coloration in Coraciiformes

Abstract What drives the evolution of plumage color in birds? Bird color is likely to be under both natural and sexual selection where natural selection may favor evolution toward crypsis or camouflage whereas sexual selection may favor evolution toward conspicuousness. The responses to selection are predicted to relate to species’ ecology, behavior, and life history. Key hypotheses have focused on habitat and light environment, breeding strategy, territoriality, and hunting behavior. We tested these potential causes of color variation in the Coraciiformes, a colorful clade of non-passerine birds, using phylogenetic comparative methods and data on chromatic and achromatic properties of plumage coloration measured from museum specimens. We found that correlates of color evolution in Coraciiformes vary across body regions and depend on the focal color property (chromatic or achromatic properties of plumage coloration). While the light environment showed widespread effects on coloration in multiple body regions for both color properties, selection pressures related to behavioral characteristics had more spatially localized effects (e.g. territoriality on achromatic properties of wing feathers and hunting strategy on chromatic properties of belly feathers). Our results reveal both general patterns that may hold across other bird clades and more nuanced effects of selection that are likely to be mediated through the visual ecology of the signaler and receiver and the behavioral characteristics of Coraciiform species.

A New Focal Mechanism Calculation Algorithm (REFOC) Using Inter‐Event Relative Radiation Patterns: Application to the Earthquakes in the Parkfield Area

AbstractAccurate earthquake focal mechanisms are essential for solving fault zone structure, estimating stress variations, and assessing seismic hazards. Small earthquakes' focal mechanisms are usually solved using P‐wave first‐motion polarities and/or S‐/P‐wave amplitude ratios, which are limited due to the low signal‐to‐noise ratio of small‐earthquake waveforms and a limited number of three‐component seismograms. To increase the number of high‐quality focal mechanisms, we develop a method that utilizes the inter‐event relative radiation patterns to perform a joint focal mechanism inversion of numerous clustered events (called REFOC). The method first uses P‐wave polarities and S‐/P‐wave amplitude ratios to constrain the initial solutions and then combines these solutions and the inter‐event P‐/P‐wave and S‐/S‐wave amplitude ratios to refine solutions. For example, we apply the method to 38,413 earthquakes in the Parkfield region, California. The REFOC outperforms traditional methods with 57% more solutions with &lt;55° uncertainties (&gt;70% of the catalog events) and 126% more solutions with &lt;25° uncertainties (&gt;40% of the catalog events), illuminating unprecedented fine‐scale rupture processes. Instead of rupturing along the main fault, many M &lt; 2 focal mechanisms show &gt;45° angular differences from the 2004 Mw 6.0 Parkfield earthquake. The variation of focal mechanism properties is spatially related to the variation of fault strength and geometry, and temporally correlated with the shear stress variations before, during, and after the 2004 Mw 6.0 earthquake. The observations highlight the potential of applying REFOC to monitor unprecedented details of fault zone structure and stress field, providing new insights into fault rupture physics, seismotectonic processes, and seismic hazards.

Refined Earthquake Focal Mechanism Catalog for Southern California Derived With Deep Learning Algorithms

AbstractEarthquake focal mechanisms, determined with P‐wave polarities and S/P amplitude ratios, are primary data for analyzing fault zone geometry, sense of slip, and the crustal stress field. Solving for the focal mechanisms of small earthquakes is often challenging because phase arrivals and first‐motion polarities are hard to be separated from noise. To overcome this challenge, we implement convolutional‐neural‐network algorithms (Ross, Meier, &amp; Hauksson, 2018, Ross, Meier, Hauksson, &amp; Heaton, 2018, https://doi.org/10.1029/2017jb015251, https://doi.org/10.1785/0120180080) to detect additional phases and polarities. Using both existing and these new data, we build a high‐quality focal mechanism catalog of 297,478 events that occurred from 1981 to 2021 in southern California with the HASH method of Hardebeck and Shearer (2002), https://doi.org/10.1785/0120010200, Hardebeck and Shearer (2003), https://doi.org/10.1785/0120020236. The new focal mechanism catalog is overall consistent with the standard catalog (Yang et al., 2012, https://doi.org/10.1785/0120110311) but includes 40% more focal mechanisms, and is more consistent with moment tensor solutions derived using waveform‐fitting methods. We apply the new catalog to identify changes in focal mechanism properties caused by the occurrences of large mainshocks such as the 2010 Mw7.2 El Mayor‐Cucapah and 2019 Mw7.1 Ridgecrest earthquakes. Such changes may be associated with co‐seismic stress drops, post‐seismic deformation processes, and static stress changes on a regional scale. The new high‐resolution catalog will contribute to improved understanding of the crustal stress field, earthquake triggering mechanisms, fault zone geometry, and sense of slip on the faults in southern California.

Phantastic Content

Phantastic interpreters of the emotions in Aristotle argue that a quasi-perceptual faculty, phantasia, is responsible for grasping the relevant value content. This article argues that phantasia cannot do this work. Rather, it claims, a phantastic account either collapses into the straight-up perceptual account or it fails to offer a cognitive account at all (despite the claims made by some of its adherents). According to the first option the focal value properties, such as slights and danger, are part of perceptual content from the start. It ends by proposing that phantastic interpreters are better off opting for the straight-up perceptual account, a view that has wide-ranging implications for our interpretation of Aristotle.