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We propose color polarization multiplexing metalenses composed by two sets of cross nanoholes etched on the silver film. Cross nanoholes are arranged on the concentric rings and they are optimized to be equivalent to half wave plates for two different wavelengths. This design can ensure the effective conversion between the right-handed and left-handed circular polarization and obtain the focusing field with high signal-to-noise ratio. The phase shift of metalens is introduced through the rotation of the cross nanoholes, and the proposed color polarization multiplexing metalens easily realize the wavelength controllable beam focusing by rotating the cross nanoholes along opposite directions. The polarization conversion theory provides the basis for the design of the metalenses. The simulation experiments for monochromatic and color polarization multiplexing metalenses show the performance of the proposed method. Our designed color polarization multiplexing metalenses possess the advantageous of color control, polarization multiplex and high focusing quality, and they are helpful for the applications of metalenses in optical integration and visible light imaging.

The three-dimensional vibration of circular rings coupled by elastic elements is investigated in this paper. The vibration characteristics of a single circular ring are examined first analytically and experimentally and then used as building blocks for a stack of concentric rings connected by elastic insulators, which is used as an approximate-model of a disk-type transformer winding. The key outcomes of this research are a more realistic model for transformer winding vibration and determining its three-dimensional vibration characteristics. The model is also verified experimentally. An experimental-based numerical method is also developed for identifying the stiffness and damping properties of the elastic elements.

Background Australian adolescents with low motor competence (LMC) have higher fracture rates and poorer bone health compared to European normative data, but currently no normative data exists for Australians. Aims To examine whether there were bone health differences in Australian adolescents with LMC or Developmental Coordination Disorder (DCD) when compared to typically developing age-matched Australian adolescents. Methods and Procedures Australian adolescents aged 12–18 years with LMC/DCD (n = 39; male = 27; female = 12) and an Australian comparison sample (n = 188; boys = 101; girls = 87) undertook radial and tibial peripheral Quantitative Computed Tomography (pQCT) scans. Stress Strain Index (SSI (mm3)), Total Bone Area (TBA (mm2)), Muscle Density (MuD [mgcm3]), Muscle Area (MuA [cm2]), Subcutaneous Fat Area (ScFA [cm2]), Cortical Density (CoD [mgcm3]), Cortical Area (CoD [mm2]), cortical concentric ring volumetric densities, Functional Muscle Bone Unit Index (FMBU: (SSI/bone length)) and Robustness Index (SSI/bone length^3), group and sex differences were examined. Outcome and Results The main finding was a significant sex-x-group interaction for Tibial FMBU (p = .021), Radial MuD (p = .036), and radial ScFA (p = .002). Boys with LMC/DCD had lower tibial FMBU scores, radial MuD and higher ScFA than the typically developing age-matched sample. Conclusion and Implications Comparisons of bone measures with Australian comparative data are similar to European findings however sex differences were found in the present study. Australian adolescent boys with LMC/DCD had less robust bones compared to their well-coordinated Australian peers, whereas there were no differences between groups for girls. These differences may be due to lower levels of habitual weight–bearing physical activity, which may be more distinct in adolescent boys with LMC/DCD compared to girls.

COVIS (COmpetition between Verbal and Implicit Systems; Ashby, Alfonso-Reese, & Waldron, 1998) is a prominent model of categorization which hypothesizes that humans have two independent categorization systems – one declarative, one associative – that can be recruited to solve category learning tasks. To date, most COVIS-related research has focused on just two experimental tasks: linear rule-based (RB) tasks, which purportedly encourage declarative rule use, and linear information-integration (II) tasks, which purportedly require associative learning mechanisms. We introduce and investigate a novel alternative: the concentric-rings task, a nonlinear category structure that both humans and pigeons can successfully learn and transfer to untrained exemplars. Yet, despite their broad behavioral similarities, humans and pigeons achieve their successful learning through decidedly different means. As predicted by COVIS, pigeons appear to rely solely on associative learning mechanisms, whereas humans appear to initially test but subsequently reject unidimensional rules. We discuss how variants of our concentric-rings task might yield further insights into which category-learning mechanisms are shared across species, as well as how categorization strategies might change throughout training.

Natural gas extraction (NGE) has expanded rapidly in the United States in recent years. Despite concerns, there is little information about the effects of NGE on air quality or personal exposures of people living or working nearby. Recent research suggests NGE emits polycyclic aromatic hydrocarbons (PAHs) into air. This study used low-density polyethylene passive samplers to measure concentrations of PAHs in air near active (n=3) and proposed (n=2) NGE sites. At each site, two concentric rings of air samplers were placed around the active or proposed well pad location. Silicone wristbands were used to assess personal PAH exposures of participants (n=19) living or working near the sampling sites. All samples were analyzed for 62 PAHs using GC-MS/MS, and point sources were estimated using the fluoranthene/pyrene isomer ratio. ∑PAH was significantly higher in air at active NGE sites (Wilcoxon rank sum test, p < 0.01). PAHs in air were also more petrogenic (petroleum-derived) at active NGE sites. This suggests that PAH mixtures at active NGE sites may have been affected by direct emissions from petroleum sources at these sites. ∑PAH was also significantly higher in wristbands from participants who had active NGE wells on their properties than from participants who did not (Wilcoxon rank sum test, p < 0.005). There was a significant positive correlation between ∑PAH in participants’ wristbands and ∑PAH in air measured closest to participants’ homes or workplaces (simple linear regression, p < 0.0001). These findings suggest that living or working near an active NGE well may increase personal PAH exposure. This work also supports the utility of the silicone wristband to assess personal PAH exposure. CAPSULE: Living or working near an active natural gas extraction well may increase an individual’s PAH exposure.

This letter presents a graphene–based tunable circular reactive impedance substrate (G–CRIS) operating at THz frequency. The proposed RIS is composed of sectoral graphene patch elements, arranged in two concentric rings and printed over silicon dioxide layer which is backed by a thin gold layer. The reactive behavior of the CRIS is made tunable by applying different chemical potential on graphene patches. This tunable CRIS is employed further to improve the operational bandwidth of a THz antenna. The CRIS loaded antenna exhibits miniaturized resonance at the lower band and wideband characteristics at the upper band. Both gain and efficiency of the antenna have been studied throughout the operating band. It is found that at THz frequency this graphene–based RIS is more suitable than metallic RIS for controlling the operational bandwidth.

Background Cholera is known to be transmitted from person to person, and inactivated oral cholera vaccines (OCVs) have been shown to confer herd protection via interruption of this transmission. However, the geographic dimensions of chains of person-to-person transmission of cholera are uncertain. The ability of OCVs to confer herd protection was used to define these dimensions in two cholera-endemic settings, one in rural Bangladesh and the other in urban India. Methods Two large randomized, placebo-controlled trials of inactivated OCVs, one in rural Matlab, Bangladesh and the other in urban Kolkata, India, were reanalyzed. Vaccine herd protection was evaluated by relating the risk of cholera in placebo recipients to vaccine coverage of surrounding residents residing within concentric rings. In Matlab, concentric rings in 100-m increments up to 700m were evaluated; in Kolkata, 50-m increments up to 350m were evaluated. Results One hundred and eight cholera cases among 24667 placebo recipients were detected during 1year of post-vaccination follow-up at Matlab; 128 cholera cases among 34968 placebo recipients were detected during 3 years of follow-up in Kolkata. Consistent inverse relationships were observed between vaccine coverage of the ring and the risk of cholera in the central placebo recipient for rings with radii up to 500m in Matlab and up to 150m in Kolkata. Conclusions These results suggest that the dimensions of chains of person-to-person transmission in endemic settings can be quite large and may differ substantially from setting to setting. Using OCVs as ‘probes' to define these dimensions can inform geographical targeting strategies for the deployment of these vaccines in endemic settings.

Kenaf (Hibiscus cannabinus) has been widely grown in Malaysia because of its fiber content and economic value. In October 2019, blight symptoms were observed on kenaf leaves in a plantation in Chuping, Perlis, Malaysia. The symptoms appeared as irregular, yellowish to brownish water-soaked lesions, which expanded and are accompanied by pycnidial formation in concentric rings. At severe stage, the blighted leaves became dried and defoliated. This study aimed to investigate the causal pathogen of the leaf blight of H. cannabinus. Overall, 20 fungal isolates recovered from the blighted leaves of H. cannabinus were identified as Coniella javanica based on their morphological characteristics and DNA sequences of the internal transcribed spacer (ITS) region and translation elongation factor 1-α (TEF1-α) gene. Phylogenetic analysis of combined dataset of the ITS and TEF1-α, congregated the fungal isolates with the reference isolates of C. javanica (CBS 455.68 and GUE-29). The pathogenicity of C. javanica isolates was confirmed through pathogenicity tests. To our knowledge, this is the first report of C. javanica causing the leaf blight of H. cannabinus in Malaysia.

Background and Objective: The high mortality rate associated with coronary heart disease (CHD) has driven intensive research in cardiac imaging and image analysis. The advent of computed tomography angiography (CTA) has turned non-invasive diagnosis of cardiovascular anomalies into reality as calcified coronary plaques can be easily identified due to their high intensity values. However, the detection of non-calcified plaques in CTA is still a challenging problem because of lower intensity values, which are often similar to the nearby blood and muscle tissues. In this work, we propose the use of mean radial profiles for the detection of non-calcified plaques in CTA imagery.\ud \ud Methods: Accordingly, we computed radial profiles by averaging the image intensity in concentric rings around the vessel centreline in a first stage. In the subsequent stage, an SVM classifier is applied to identify the abnormal coronary segments. For occluded segments, we further propose a derivative-based method to localize the position and length of the plaque inside the segment.\ud \ud Results: A total of 32 CTA volumes were analysed and a detection accuracy of 88.4% with respect to the manual expert was achieved. The plaque localization accuracy was computed using the Dice similarity coefficient and a mean of 83.2% was achieved.\ud \ud Conclusion: The consistent performance for multi-vendor, multi-institution data demonstrates the reproducibility of our method across different CTA datasets with a good agreement with manual expert annotations.

Four surface resistance test electrodes are compared using a selection of materials under similar test conditions. The results vary considerably with some materials due to variation in surface resistivity. Using a relatively uniform material two concentric ring electrodes compliant with the same standard differed in results by a factor of 1.8. Silver stripe and copper tape electrodes gave results a factor 0.4 and 0.7 compared to the reference electrode. A 2-pin electrode gave results a factor 4.7 greater. The 2 pin probe cannot be expected to give similar results to the other electrodes for materials that have variable resistivity.

9 páginas, 8 figuras., Mapping pollen concentrations is of great interest to study the health impact and ecological implications or for forestry or agronomical purposes. A deep knowledge about factors affecting airborne pollen is essential for predicting and understanding its dynamics. The present work sought to predict annual Quercus pollen over the Castilla and León region (Central and Northern Spain). Also to understand the relationship between airborne pollen and landscape. Records of Quercus and Quercus pyrenaica pollen types were collected at 13 monitoring sites over a period of 8 years. They were analyzed together with land use data applying the Concentric Ring Method (CRM), a technique that we developed to study the relationship between airborne particle concentrations and emission sources in the region. The maximum correlation between the Quercus pollen and forms of vegetation was determined by shrubland and “dehesa” areas. For the specific Qi pyrenaica model (Q. pyrenaica pollen and Q. pyrenaica forest distribution), the maximum influence of emission sources on airborne pollen was observed at 14 km from the pollen trap location with some positive correlations up to a distance of 43 km. Apart from meteorological behavior, the local features of the region can explain pollen dispersion patterns. The method that we develop here proved to be a powerful tool for multi-source pollen mapping based on land use., The authors are grateful to Anne Collins for editing the English and the Health Department of the Castilla and León Government for funding the RACYL. This study was partially supported by the Spanish Ministry of Science and Innovation (Grant CGL2014-52556-R).

Restricted by the working principles, the traditional ring rolling technologies are only fit for fabricating concentric rings while it is difficult for them to fabricate eccentric rings. So this study is devoted to put forward an innovative eccentric ring rolling (ERR) method for fabricating eccentric rings. Firstly, to guarantee ERR successfully, the technological design principles and methods for the rolls, ring workpiece and objective eccentric ring are presented and the rolling conditions in ERR are correspondingly determined. Then, the deforming mechanisms and rolling defects in ERR are analyzed through FE simulations. Finally, to eliminate the rolling defects of uneven axial height distribution of the rolled eccentric ring, the optimization design methods for the ring workpiece and the corresponding rolling conditions are presented. Through simulations and experiments, it is illustrated that qualified eccentric rings with even axial height distribution and highly accurate thickness distribution along the tangential direction can be rolled by ERR and thus the presented ERR method is promising in fabricating eccentric rings.

Organisms rely on many signaling molecules to control how their cells grow, divide and heal. For example, when the cell membrane is damaged, two signaling proteins, Rho and Cdc42, are recruited to wounds and activated to promote repair. Active Rho and active Cdc42 form two concentric rings at the membrane to direct the closure of the wound. Rho and Cdc42 belong to the RhoGTPase family, a group of proteins that act as molecular switches and alternate between active and inactive forms. At the level of the cell, RhoGTPases are only active in the tiny patches of the membrane where they bind. However, individual proteins hop on and off membranes in a matter of seconds, only staying bound for short periods. This mechanism is controlled by a regulatory protein known as RhoGDI, and it allows RhoGTPases to form precise patterns of activity at membranes – such as the rings that surround a wound site. However, it was not known exactly how RhoGDI regulates the activity of RhoGTPases over space and time, partly because it is difficult to study these proteins in the laboratory. To fill this knowledge gap, Golding, Visco et al. developed new fluorescent probes to track Rho and Cdc42 in wounded cells from frogs and on artificial membranes. The experiments showed that pools of inactive Cdc42 accumulated on membranes, alongside the active form of the protein. RhoGDI removed both active and inactive RhoGTPases from artificial and frog cell membranes. In fact, removing active Rho and Cdc42 proteins from the cell membrane was necessary to form the spatial patterns of RhoGTPase activity observed in wounded frog cells. The findings of Golding, Visco et al. help to understand how RhoGDI proteins regulate RhoGTPases and provide new tools to further study these proteins. In humans, mutations in either RhoGDI or Cdc42 are responsible for severe conditions such as Nephrotic Syndrome Type 8 or Takenouchi-Kosaki syndrome. In the future, this work may aid the development of treatments and cures for these conditions.

In the present study, development of trilobed stem is investigated in Distimake tuberosus (Convolvulaceae) by histological methods. Increase in stem thickness and formation of trilobed stem was achieved by forming crescent shaped successive cambial segments from the pericyclic parenchyma at three equidistant sites. In contrast, the alternate segments of the vascular cambium were functionally less active, dividing leisurely (referred henceforth as functionally less active cambium) and did not form the successive cambium. The newly formed cambial segments divide bi-directionally and produced its derivatives, while functionally less active segment lagged behind. The secondary xylem formed from the functionally less active cambial segments have unique pattern of vessels distribution i.e., wide vessels rare or completely absent. Parenchyma (both, axial and ray) proliferation, formation of ray cambium, functionally inverse cambia, tyloses in fibriform vessels and the occurrence of bordered pits in xylem ray cells are observed in all samples. Root diameter increased by developing concentric rings of successive cambia and maintained a circular outline. Formation of successive cambia on three sides and alteration in stem outline may be associated with protection of conducting elements against stem torsion and internal injury. Formation of conducting elements from the ray cambium and internal cambium suggest rapid and safe conduction of photosynthate, water and mineral elements.

The purpose of this study was to clarify the spatiotemporal structure of human mobility patterns in the Tokyo metropolitan area (TMA), and to reveal the regional characteristics and differences of dynamic mobility behaviour therein, from the individual, location, and time-use perspectives. Furthermore, this study aimed to describe daily urban rhythms in terms of human mobility. For these purposes, we constructed a GIS microscope by handling our geo-tagged big data based on the person-trip data. Through a multi-view study, we affirmed that the spatiotemporal mobility patterns had a certain consistency at different scales. Results suggested that the human mobility patterns expressed a typical inter-regional functional complementarity and a certain daily rhythm under the layout of TMA’s quadruple concentric ring structure. By grasping the multidimensional dynamic pattern of human behaviour, researchers, the general public, and policymakers can be brought into alignment towards the goal of sustainable urban planning.

Clitellate annelids (e.g., segmented earthworms, leeches) secrete proteinaceous cocoons into which eggs are deposited. The process of cocoon production is characterized by the coordinated release of micro-granules from secretory cells positioned asymmetrically within the clitellum. Collectively, these assemble into a tubular cocoon sheath that is sealed at either end by globular opercula. By transmission electron microscopy (TEM), we show here that granules destined to the cocoon operculum in the leech, Erpodbdella obscura, display a series of concentric rings surrounding a structureless core with dimensions approximating a single nanoglobule found in the operculum. Upon their channeling to the surface through narrow tubules, granules are secreted into the cocoon lumen where they appear to fragment upon contact with the operculum matrix. The distribution of partial concentric ring structures throughout the operculum suggests that granular fusion causes dynamic fragmentation of outer surface material, which thereafter integrates into operculum nanoglobules and cavities. Other granules within the same secretory cell display a punctate pattern and likely fuse with the cocoon sheath prior to crystallization.

Eosinophilic esophagitis (EoE) is believed to be a rare pathological condition that is characterized by dense infiltration of eosinophils in esophageal epithelial layer. Occurrence of this disease worldwide has started increasing rapidly in the last decade. Routine endoscopic observations can help in diagnosis only if clear longitudinal furrows or multiple concentric rings are observed but does not give any definitive conclusion in the early stages. Hence esophageal tissue samples are collected from multiple sites by biopsy and the number of eosinophils is counted after staining. Such a procedure is time consuming and has an inherent risk of bleeding, eventually damaging esophagus. Hence we developed a resonance Raman spectroscopy based approach to detect eosinophils in esophagus using mouse models. Our results show the presence of eosinophils in mice esophageal tissues suffering from inflammation by administering interleukin-33 while there are none in control mice. We believe this method can be used in clinical application for diagnosing EoE in the near future.

Mechanical faults in the winding are often related to the changes in the vibro-acoustical response of the transformers with respect to the electromagnetic force in winding. Understanding of the effects of the faults on the vibration characteristics of transformer windings is useful when diagnosing winding faults using transformer’s vibration signature, and when predicting the environmental noise emission from transformers. In this paper, mechanical faults, such as failure of interlayer insulation pressboards and local winding deformations, of the disk-type windings in a 110-kV power transformer, and their effects on the vibration responses of the windings are presented. The disk-type windings are also experimentally modeled by a stack of coupled concentric rings with well-defined faults. A good qualitative agreement is found between measured responses of the power transformer and of the stack of coupled concentric rings. The dependence of the response of the stack on increasing degree of faults provides useful details for understanding the cumulative effect of the faults on the winding’s vibration characteristics. Methods for identifying the location and severity of the faults based on the measured vibration responses are also outlined.

Objective There is a long interest in using EEG measurements to inform transcranial Electrical Stimulation (tES) but adoption is lacking. The conventional approach is to use anatomical head-models for both source localization (the EEG inverse problem) and current flow modeling (the tES forward model), but this approach is computationally demanding, requires an anatomical MRI, and strict assumptions about the target brain regions. We evaluate techniques whereby tES dose is derived from EEG without the need for an anatomical head model or assumptions. Approach The approaches are verified using a Finite Element Method (FEM) simulation of the EEG generated by a dipole, oriented either tangential or radial to the surface, and then simulating brain current flow produced by various model-free techniques including: (1) Voltage-to-voltage, (2) Voltage-to-Current; (3) Laplacian; and two Ad-Hoc techniques (4) Dipole sink-to-sink; and (5) Sink to Concentric Ring. These model-free approaches are compared to a numerically optimized dose that assumes perfect understanding of the dipole location and head anatomy. We vary the number of electrodes from a few to over three hundred, with focality or intensity as optimization criterion. Main results Our results demonstrate how simple Ad-Hoc approaches can achieve reasonable targeting for the case of a cortical dipole with 2–8 electrodes and no need for a model of the head. Significance For its simplicity and linearity, model-free EEG guided lends itself to broad adoption and can be applied to a static (tDCS), time-variant (e.g. tACS, tRNS, tPCS), or closed-loop tES. Figure options Download full-size image Download high-quality image (1118 K) Download as PowerPoint slide Figure options Download full-size image Download high-quality image (1499 K) Download as PowerPoint slide

We investigate whether field homogeneity of a magnetic assembly can be optimized by varying the remanence of its constituting magnetic segments. We specifically study this hypothesis for a Halbach cylinder using a numerical model, MagTense. We consider a Halbach cylinder consisting of six layers of three concentric rings, each ring made from 16 segments. We show that ideally, the homogeneity can reach close to 1 ppm for a finite magnet. We then proceed to consider a real world set of magnet segments, i.e. non-ideal magnets with a variation in their remanence. This reduces the field homogeneity to about 1000 ppm when considering a Gaussian perturbation of the remanence with a standard deviation of 1 %. However, we also show that the reduction in homogeneity may be countered by organizing the magnet pieces found through optimization, which is possible if each magnet segment is well characterized experimentally. We note that the presented method is applicable to any case where homogeneity of the field is important. The results we present are considered for the specific case of nuclear magnetic resonance for concretenes.

Air pollution has great impacts on both human health and economic development. The difference in air pollution concentrations between urban and rural areas (urban haze island) is a widespread phenomenon. However, a method that can effectively depict the features of this phenomenon remains lacking. This study developed a method based on the concentric ring approach and modified sigmoid function to identify urban haze islands and extract three features: the background value of urban haze islands (BUHI), the intensity of urban haze islands (IUHI) and the extent of urban haze islands (EUHI). Using this method, we analyzed the PM2.5 concentration data from 346 Chinese cities in 2016 and examined the spatial characteristics and driving factors of the three features of urban haze islands. The results showed that about two-thirds (218/346) of Chinese cities had a significant urban haze island phenomenon, with an average BUHI of 36.8 μg/m3, an IUHI of 11.3 μg/m3, and an EUHI of 7.7 km. The developed method can successfully capture the variations of PM2.5 concentration, and the RMSE of the fitting curve was 0.46 μg/m3. On the national scale, natural factors had a greater impact (with the standardized regression coefficients varying from −0.74 ~ 0.80) on the BUHI and IUHI than socioeconomic factors (-0.32 ~ 0.32), while socioeconomic factors had a greater impact (0.29 ~ 0.38) on the EUHI than natural factors (−0.23 ~ 0.17). This study proposes a new and simple method to identify urban haze islands with high efficiency and wide applicability. Our results can be helpful for understanding urban-rural environmental differences and providing guidance for policymakers.

The Dounan manganese deposit in the Middle Triassic Falang Formation has prominent features like oolitic Mn ores, which are in micronodule form. Detailed petrological, mineralogical, and geochemical analyses were carried out on bulk samples and typical micronodules to clarify the deposit's material source, metallogenic environment, genesis, and formation mechanism of the micronodules. The ore minerals are mainly braunite, manganite, Ca-rhodochrosite, kutnahorite, and manganocalcite. The micronodules usually exhibit a detrital nucleus and concentric rings consisting of braunite and Mn carbonate. Good correlations were detected among the Si, Al, Ti, and ∑REE in the ore compositions. The trace elements in the bulk samples and micronodules exhibited similar distribution patterns, and both are enriched in Co, Ni, and Sr and depleted in Cr, Rb, Zr, Nb, Ba, and Th. The micronodules, which are dominated by braunite, are more enriched in V, Co, Ni, Cu, Zn, Mo, and U than the Mn-carbonate-based ones. The ∑REE of the micronodules was higher than that of the bulk samples, but REE patterns were similar. δCe showed weakly positive or negative anomalies, and δEu showed weakly positive anomalies. These results suggest that the ore-forming materials were from various sources, which could have included weathered Mn-bearing rocks from the Yuebei palaeoisland and Emeishan basalts from adjacent ancient lands, as well as a hydrothermal source; mineralisation occurred in a marginal shallow-marine environment with weakly alkaline seawater during fluctuating redox conditions. The micronodules formed via a combination of chemical and biological processes.

Flow induced by an electrohydrodynamic (EHD) gas pump in a circular tube, which has the primary emitting electrodes flush mounted evenly on the tube wall and the secondary emitting electrodes attached to a concentric ring, has been experimentally investigated for two different configurations with varied gap distance. Earlier studies have shown that the flow produced by the primary emitting electrodes alone has a velocity profile similar to a wall jet with higher velocities near the wall and smaller velocities at the core region. The main objective of the present study is to increase the volume flow rate by the addition of secondary electrodes. To this end, the secondary electrodes have been attached to a concentric ring at the same level of the primary electrodes. Two configurations (with either 4 or 8 secondary emitting electrodes) are considered. In addition, two gap distances between the primary and secondary electrodes are considered as well. Velocities are measured in both radial and angular directions and then integrated to obtain the volume flow rate. The results obtained are compared with those produced by the primary electrodes alone to give additional insight to the problem.

It has been a big challenge to effectively collect coarse and fine droplets from the air by compact and light equipment. In this report, a novel strategy of collecting coarse and fine droplets from the air, which employs an ultrasonic field in an air gap between a flat radiation surface and reflector, is demonstrated. Coarse and fine droplets (PM2.5-10 and PM2.5) can be effectively collected onto the reflector’s surface when the air gap thickness is proper. The radiation surface works in a flexural vibration mode at 56.9 kHz, and the collected droplets may form concentric rings and irregular shape on the reflector’s surface. Analyses show that both the acoustic streaming and acoustic radiation force contribute to the collection.

Commercial fused silica (50 mm diameter × 5 mm thickness) irradiated by single pulse of Nd:YAG laser (1064 nm, 12 ns) is experimentally investigated. The exit surface of fused silica is easier to be damaged than the entrance surface, so in this paper we only study the damage formed on the exit surface. The typical damage morphologies, irradiated at normal and oblique incidence, were observed with scanning electron microscope and atomic force microscope. The concentric ring structures with a central defect precursor are appeared in all damage sites. Furthermore, the whole damage sites are filled with the surface periodic striped structures, which direction is perpendicular to the incident electric field. Further analysis show that the incident energy has great effect on the size of damage sites, the depth of damage sites, and also the depth of the ripples, but has no effect on the period of the ripples. Additional experiments are performed to investigate the dependency between the period of ripples and the incident angle.

Summary A bathymetry model was developed from a series of Landsat Thematic Mapper (TM) images to assist discrimination of hydrologic processes on a low-relief, stable saline playa in Dixie Valley, Nevada, USA. The slope of the playa surface, established by field survey on a reference transect, enabled calculation of relative elevation of the edges of pooled brine mapped from Landsat TM5 band 5 reflectance (TMB5) in the 1.55-1.75 µm shortwave infrared region (SWIR) of the spectrum. A 0.02 TMB5 reflectance threshold accurately differentiated the shallow (1–2 mm depth) edges of pools. Isocontours of equal elevations of pool margins were mapped with the TMB5 threshold, forming concentric rings that were assigned relative elevations according to the position that the pool edges intersected the reference transect. These data were used to fit a digital elevation model and a curve for estimating pooled volume given the distance from the playa edge to the intersection of the pool edge with the reference transect. To project pooled volume using the bathymetric model for any TM snapshot, within a geographic information system, the 0.02 TMB5 threshold is first used to define the edge of the exposed brine. The distance of this edge from the playa edge along the reference transect is then measured and input to the bathymetric equation to yield pooled volume. Other satellite platforms with appropriate SWIR bands require calibration to Landsat TMB5. The method has applicability for filling reservoirs, bodies of water that fluctuate and especially bodies of water inaccessible to acoustic or sounding methods.

The Mars Global Digital Dune Database (MGD 3 ) is complete and now extends from 90°N to 90°S latitude. The recently released south pole (SP) portion (MC-30) of MGD 3 adds ∼60,000 km 2 of medium to large-size dark dune fields and ∼15,000 km 2 of sand deposits and smaller dune fields to the previously released equatorial (EQ, ∼70,000 km 2 ), and north pole (NP, ∼845,000 km 2 ) portions of the database, bringing the global total to ∼975,000 km 2 . Nearly all NP dunes are part of large sand seas, while the majority of EQ and SP dune fields are individual dune fields located in craters. Despite the differences between Mars and Earth, their dune and dune field morphologies are strikingly similar. Bullseye dune fields, named for their concentric ring pattern, are the exception, possibly owing their distinctive appearance to winds that are unique to the crater environment. Ground-based wind directions are derived from slipface (SF) orientation and dune centroid azimuth (DCA), a measure of the relative location of a dune field inside a crater. SF and DCA often preserve evidence of different wind directions, suggesting the importance of local, topographically influenced winds. In general however, ground-based wind directions are broadly consistent with expected global patterns, such as polar easterlies. Intriguingly, between 40°S and 80°S latitude both SF and DCA preserve their strongest, though different, dominant wind direction, with transport toward the west and east for SF-derived winds and toward the north and west for DCA-derived winds.

Balo's concentric sclerosis (BCS) and tumefactive demyelination (TD) are considered atypical forms of multiple sclerosis (MS). Balo lesions are characterized by concentric rings corresponding to alternating bands of demyelination and relatively preserved myelin (Hu and Lucchinetti, 2009). Tumefactive lesions are pseudotumoural demyelinating lesions of > 2 cm and may have an open ring-enhancing magnetic resonance imaging appearance (Hu and Lucchinetti, 2009; Lucchinetti et al., 2008; Altintas et al., 2012). We present a patient who developed limb weakness and focal seizures secondary to a lesion radiologically and histopathologically consistent with BCS who, six months later, developed a tumefactive demyelinating lesion. This is the first description of BCS and TD occurring in the same patient and is particularly notable because of the lack of any other more typical demyelinating lesions on the MRIs. The nature of BCS and TD in relation to more typical multiple sclerosis is discussed.

We theoretically investigate the strong-field ionization of hydrogen atom in bichromatic laser fields of circular polarization by calculating the momentum distributions. We find that the momentum distributions consist of a series of arc fringes, which correspond to the different above-threshold ionization peaks, and the momentum distributions generally are inversion asymmetric owing to the interference happening between the different ionization channels. But if only one ionization channel is considered, the momentum distributions are perfect and concentric rings, and as the number of ionization channel increases, the asymmetry of the momentum distribution becomes more and more notable.

In recent years, the problem of the production of localized waves has been analyzed in various ways, from both a theoretical and a practical point of view. We present here a way in which to construct a suitable experimental setup, so as to obtain highly localized energy. On the basis of a vectorial treatment already studied for a specific source (namely, a ring-shaped aperture over a metallic screen), we evaluate the amount of energy supplied by a single Bessel beam. Then, by analyzing the geometric characteristics of the experimental setup, we can establish the position of further rings, so as to increase the localized energy to a maximum.

C/C–ZrC–SiC composites with continuous ZrC–SiC ceramic matrix were prepared by a multistep technique of precursor infiltration and pyrolysis process. Ablation properties of the composites were tested under an oxyacetylene flame at 3000 °C for 120 s. The results show that the linear ablation rate of the composites was about an order lower than that of pure C/C and C/C–SiC composites as comparisons, and the mass of the C/C–ZrC–SiC composites increased after ablation. Three concentric ring regions with different coatings appeared on the surface of the ablated C/C–ZrC–SiC composites: (i) brim ablation region covered by a coating with layered structure including SiO 2 outer layer and ZrO 2 –SiO 2 inner layer; (ii) transition ablation region, and (iii) center ablation region with molten ZrO 2 coating. Presence of these coatings which acted as an effective oxygen and heat barrier is the reason for the great ablation resistance of the composites.

Based on Landsat MSS and TM images from 1974, 1988, and 2004, we conducted a case study of the Manwan Dam along the Lancang (Mekong) River to determine the influencing distance of dam construction and reservoir impoundment on land use. Spatio-temporal variation in land use was analyzed within 14 adjacent buffer zones around the dam site (concentric rings) and in upstream and downstream areas along the riverway (linear tract). Grassland increased with the greatest dynamic degree in the 1974–1988 period, whereas water area increased extensively in the 1988–2004 period. The integrated dynamic degrees of forestland were low in both periods. The integrated land use dynamics in the 14 concentric rings showed that the impact of dam construction extended to a threshold distance of 5000–6000 m from the dam site during the 1974–1988 period and to 2000–3000 m during the 1988–2004 period. The transformational patch density in the 14 linear buffer zones indicated that the impact of reservoir impoundment on land use conversion exhibited a threshold distance of 3000 m from the riverway. The impact intensity of dam construction in the concentric rings and linear buffer zones tended to decline with increasing distance from the dam site or riverway. The impacts of dam construction and reservoir impoundment were larger in upstream locations than in downstream ones. Our results enhance our understanding of the threshold of dam construction and may guide the management of dam construction on a regional landscape level.

The increase in employment away from Central Business Districts raises questions about the continued applicability of the monocentric model and its prediction of the negative decline of density, yet the model continues to be used and produces reasonable results. This paper argues that while the development of multiple employment subcenters produces variation in density patterns resulting in declining goodness-of-fit of the negative exponential model when estimated using data for small areas, the overall pattern continues to be a general decline of density with distance. The negative exponential model is estimated using data on densities both for census tracts and concentric rings around the center for 43 large urban areas in the United States from 1950 to 2010. The R2 values for the estimates using the tract data decline steadily after 1970, while the ring estimates show only small decreases. It is further hypothesized that since more general measures of accessibility to employment may now better predict density at the tract level, distance to the center as a proxy incorporates increasing error, resulting in attenuation bias in the estimates of the density gradients, which was shown by comparing the tract and ring estimates.

We have firstly demonstrated fiber surface enhanced Raman scattering (SERS) sensor based on gold–silver nanoalloys fabricated by a simple and effective photochemical co-reduction method. The nanoalloys are separated into two phases: one phase located in the central circular area of fiber end puts particular emphasis on showing the dispersibility of gold, while the other one in the concentric ring region reflects more on the high enhancement effect of silver. Combining superiorities of gold and silver, fiber SERS sensor based on the biphasic gold–silver nanoalloys shows good reproducibility and high sensitivity.

Flowers and fruits of the monotypic Namibian endemic Marlothiella gummifera were examined to explore anatomical variation and to highlight problems associated with the homology of certain character states. Some unusual new features observed in the fruits and ovaries raise questions regarding the homology of fruit heteromorphy, rib oil ducts, vittae and carpophores in subfamily Apioideae. These include the irregular occurrence of heterocarpic ovaries, oil ducts on both the internal and external sides of the vascular bundles (the inner dwarf ducts), short ducts in the commissural area, and carpophores (only rarely present). The fruits of Marlothiella share several unusual features with the genus Lichtensteinia , namely concentric rings of cells around the rib oil ducts, of which the innermost are irregular in size and shape, very small vascular bundles that are usually comprised of two separate strands, and the occurrence of heteromorphy in fruits and ovaries. These two genera are morphologically very different and it is encouraging to find anatomical data to support their presumptive relationship based on molecular studies.

[EN] Non-invasive bioelectrical recordings are usually carried out by using monopolar or bipolar disc electrodes. The poor spatial resolution is one important disadvantage of this kind of electrodes tending to pick up physiological interferences. Concentric ring electrodes have already been implemented in rigid substrates to increase the spatial resolution in the recording of bioelectrical signals such as the electrocardiography (ECG) or the electroencephalography (EEG). Our goal was to develop and test a new modular active sensor made up of a disposable sensing part with concentric ring electrodes printed on a flexible substrate by thick-film technology connected to a battery powered signal conditioning circuit, and to compare it to rigid conventional concentric ring electrodes implemented on printed circuit board. Simultaneous ECG recordings were carried out using both flexible and rigid electrodes. Results show that flexible concentric ring electrodes present lower skin-electrode contact impedance, higher amplitude and lower baseline wander than the rigid ones., Authors ackowledge financial support from the Spanish Government and its MICINN (MAT2009-14564-C04-02), MICINN (TEC2010-16945), the Universitat Politècnia de Valencia trough Nuevas Líneas de Investigación Multidisciplinares (PAID-05-11) for their respective research fellowship

The flexure strength of miniature disk specimens was evaluated for both the unirradiated and irradiated CVD SiC by equibiaxial flexural test developed in this work. The results for the unirradiated specimens indicated no stress magnification at the loading point, which is often concerned in the biaxial tests for the disk specimens. Although the strength was retained after the irradiation at 1100 and 1300 °C, ∼20% of reduction was observed for the samples irradiated at 1500 °C. It is clearly seen that the smooth cleavage of large grains were frequently observed in the sample irradiated at 1500 °C comparing to specimens irradiated at lower temperatures. A substantially lower population of finer defect clusters such as loops, vacancy, and vacancy clusters may be attributed to the inhibition of the strengthening at the higher irradiation temperatures.

A digital terrain model (1000-m effective spatial resolution) of the Caloris basin, the largest well-characterized impact basin on Mercury, was produced from 208 stereo images obtained by the MESSENGER narrow-angle camera. The basin rim is far from uniform and is characterized by rugged terrain or knobby plains, often disrupted by craters and radial troughs. In some sectors, the rim is represented by a single marked elevation step, where height levels drop from the surroundings toward the basin interior by approximately 2 km. Two concentric rings, with radii of 690 km and 850 km, can be discerned in the topography. Several pre-Caloris basins and craters can be identified from the terrain model, suggesting that rugged pre-impact topography may have contributed to the varying characteristics of the Caloris rim. The basin interior is relatively smooth and shallow, comparable to typical lunar mascon mare basins, supporting the idea that Caloris was partially filled with lava after formation. The model displays long-wavelength undulations in topography across the basin interior, but these undulations cannot readily be related to pre-impact topography, volcanic construction, or post-volcanic uplift. Because errors in the long-wavelength topography of the model cannot be excluded, confirmation of these undulations must await data from MESSENGER’s orbital mission phase.

The interrelatedness of transportation development and economic growth has been a constant theme of geographic inquiries, particularly in economic and transportation geography. This paper analyzes the expansion of China's railway network, the evolution of its spatial accessibility, and the impacts on economic growth and urban systems over a time span of about one century (1906-2000). First, major historical events and policies and their effects on railway development in China are reviewed and grouped into four major eras: preliminary construction, network skeleton, corridor building, and deep intensification. All four eras followed a path of "inland expansion." Second, spatial distribution of accessibility and its evolution are analyzed. The spatial structure of China's railway network is characterized by "concentric rings" with its major axis in North China and the most accessible city gradually migrating from Tianjin to Zhengzhou. Finally, the study indicates that railway network expansion has significantly improved economic development and heavily influenced the formation of urban systems in China.

Heterotopic pancreas causing small bowel intussusception is rare. We report the case of a 24-year-old woman who presented with intermittent episodes of abdominal cramping and pain that had persisted for 10 days. A target-shaped lesion consisting of multiple concentric rings was found on the left side on contrast-enhanced computed tomography. Surgical intervention demonstrated jejunal intussusception caused by a jejunal heterotopic pancreas. Microscopically, several nesidioblastoses of pancreas were identified. Although very rare, small intestinal pancreatic rests may cause subacute bowel obstruction.

Hand injuries are an important cause of pain and disability among dentists and dental hygienists and may be due to the high pinch forces involved in periodontal work. The pinch forces required to perform scaling may be reduced by increasing the friction between the tool and fingers. The purpose of this study was to determine whether modifying the tool material, surface texture, or glove type altered the coefficient of static friction for a wet gloved finger. Seven tools with varying surface topography were machined from 13 mm diameter stainless steel and Delrin and mounted to a 6-component force plate. The textures tested were a fine, medium and coarse diamond knurled pattern and a medium and fine annular pattern (concentric rings). Thirteen subjects pulled their gloved, wet thumb pad along the long axis of the tool while maintaining a normal force of 40 N. Latex and nitrile gloves were tested. The coefficient of static friction was calculated from the shear force history. The mean coefficients of static friction ranged from 0.20 to 0.65. The coefficient of static friction was higher for a smooth tool of Delrin than one of stainless steel. Differences in the coefficient of static friction were observed between the coarse and medium knurled patterns and the fine knurled and annular patterns. Coefficients of static friction were higher for the nitrile glove than the latex glove for tools with texture. These findings may be applied to the design of hand tools that require fine motor control with a wet, gloved hand.

Purpose Motion perception abnormalities and extrastriate abnormalities have been suggested in amblyopia. Functional MRI (fMRI) and motion stimuli were used to study whether interocular differences in activation are detectable in motion-sensitive cortical areas in patients with anisometropic amblyopia. Methods We performed fMRI at 1.5 T 4 control subjects (20/20 OU), 1 with monocular suppression (20/25), and 2 with anisometropic amblyopia (20/60, 20/800). Monocular suppression was thought to be form fruste of amblyopia. The experimental stimulus consisted of expanding and contracting concentric rings, whereas the control condition consisted of stationary concentric rings. Activation was determined by contrasting the 2 conditions for each eye. Results Significant fMRI activation and comparable right and left eye activation was found in V3a and V5 in all control subjects (Average z -values in L vs R contrast 0.42, 0.43) and in the subject with monocular suppression ( z = 0.19). The anisometropes exhibited decreased extrastriate activation in their amblyopic eyes compared with the fellow eyes ( z s = 2.12, 2.76). Conclusions Our data suggest motion-sensitive cortical structures may be less active when anisometropic amblyopic eyes are stimulated with moving rings. These results support the hypothesis that extrastriate cortex is affected in anisometropic amblyopia. Although suggestive of a magnocellular defect, the exact mechanism is unclear.

We investigated the figural dynamics of filling-in processes in figures with more than one possible figure-ground organisation. Using a central disk and two concentric rings as well as similar stimuli consisting of three nested squares or parallel stripes, we tested for filling-in with different equiluminant colour combinations. We observed four modes of filling-in: First, in most of the cases, the inner ring assumed the colour of the central disk and outer ring (M1). Second, the central disk became filled-in with the colour of the inner ring, without any colour change on the outer ring (M2). Third, in a first step, the colour of the inner ring spread onto the central disk; then, in a second step, the colour of the outer ring spread over the whole stimulus (M3). This two step filling-in process has not been reported so far. Fourth, a mode (M4) was sometimes observed that was characterised by the central disk and outer ring assuming the colour of the inner ring. Thus, colour filling-in or colour spreading proceeded both in a centripetal (periphery to fovea) as well as a centrifugal direction. The colours red and yellow proved to be stronger inducers than blue and green. Conversely, the latter colours became filled-in more easily than the former. The filled-in colour was always that of the inducing stimulus, i.e., there was no colour mixture. This suggests a long-range, neural process underlying filling-in under these conditions.

An experimental procedure for gathering short-time strength data and to discriminate multiaxial failure criteria of ceramics is presented. It uses concentric rings of different diameter ratios which are subjected to internal pressure and allows specimen to have “as-fired”-surfaces. Due to mainly tensional stresses, crack-face friction effects in the material have minor influence on the discrimination of failure criteria. Test series with alumina have been executed and the results are presented.

The formation of concentric ring colonies by bacterial species Bacillus subtilis and Proteus mirabilis has been investigated experimentally, focusing our attention on the dependence of local cell density upon the bacterial motility. It has been confirmed that these concentric ring colonies reflect the periodic change of the bacterial motility between motile cell state and immotile cell state. We conclude that this periodic change is macroscopically determined neither by biological factors (i.e., biological clock) nor by chemical factors (chemotaxis as inhibitor). And our experimental results strongly suggest that the essential factor for the change of the bacterial motility during concentric ring formation is the local cell density.

The elemental composition of mineral structures in marine organisms can provide useful information to reconstruct environmental histories of individuals and distinguish populations or stocks. In cephalopods, as Octopus vulgaris, morpho-physiological description of vestigial shells may contribute to a better understanding of the physiology, of the process involved in the increment growth and may eventually provide important and useful tools for the validation of age determination methods. Nuclear microprobe analysis was used to map chemical elements in O. vulgaris vestigial shell. The maps contain elemental and morphological information, and enabled especially through Cl and Ca distributions to classify bands of concentric rings. The levels of P, Ca and Sr decrease from central region to external rings, while those of S and Cl showed an inverse tendency. Enhanced concentrations of Fe, Cu and Zn were found in external rings, and no significant variations were detected in the K and Br contents. The results indicate that three regions can be established on the basis of the elemental contents distributions. Specially, the P and Ca variability can distinguish rings from central and external regions. The differential incorporation of elements in the vestigial shell observed may reflect environmental and physiological factors that are affecting the life cycle of this species.

The number of leg-bearing segments in centipedes varies extensively, between 15 and 191, and yet it is always odd [1, 2]. This suggests that segment generation in centipedes involves a stage with double segment periodicity and that evolutionary variation in segment number reflects the generation of these double segmental units. However, previous studies have revealed no trace of this [3–5]. Here we report the expression of two genes, an odd-skipped related gene ( odr1 ) and a caudal homolog, that serve as markers for early steps of segment formation in the geophilomorph centipede, Strigamia maritima . Dynamic expression of odr1 around the proctodaeum resolves into a series of concentric rings, revealing a pattern of double segment periodicity in overtly unsegmented tissue. Initially, the expression of the caudal homolog mirrors this double segment periodicity, but shortly before engrailed expression and overt segmentation, the intercalation of additional stripes generates a repeat with single segment periodicity. Our results provide the first clues about the causality of the unique and fascinating "all-odd" pattern of variation in centipede segment numbers and have implications for the evolution of the mechanisms of arthropod segmentation.

In the frame of accurate radioactivity measurements by means of alpha-particle counting at defined low solid angles, a procedure is presented that takes into account the source's actual radioactivity distribution in the solid angle calculation. The method pertains to an axially symmetric set-up in which a thin flat source is placed parallel to the diaphragm(s) and the detector. From a digital autoradiograph, the source's radial activity distribution is assessed. The source is virtually subdivided into concentric rings and the corresponding solid angle values are weighted with the relative contribution of the annular regions-of-interest to the total radioactivity of the source.

The free vibration of solid circular plates has been studied using the generalized differential quadrature rule (GDQR). The effects such as stepped thickness, intermediate concentric ring supports, and elastic restraints have been considered. Discrete system equations for natural frequency analysis were derived based on the GDQR. Issues related to the implementation of the boundary and compatibility conditions were addressed. Two regularity conditions at the solid circular plate center were formularized, since they were not quite clear in the present literature. Some wrong applications in the implementation of both differential quadrature methods and regularity conditions at the solid circular plate center have been pointed out. Excellent results have been obtained with the presented examples.