1,185 research outputs found

    Inverse Design of Perfectly Transmitting Eigenchannels in Scattering Media

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    Light-matter interactions inside turbid medium can be controlled by tailoring the spatial distribution of energy density throughout the system. Wavefront shaping allows selective coupling of incident light to different transmission eigenchannels, producing dramatically different spatial intensity profiles. In contrast to the density of transmission eigenvalues that is dictated by the universal bimodal distribution, the spatial structures of the eigenchannels are not universal and depend on the confinement geometry of the system. Here, we develop and verify a model for the transmission eigenchannel with the corresponding eigenvalue close to unity. By projecting the original problem of two-dimensional diffusion in a homogeneous scattering medium onto a one-dimensional inhomogeneous diffusion, we obtain an analytical expression relating the intensity profile to the shape of the confining waveguide. Inverting this relationship enables the inverse design of the waveguide shape to achieve the desired energy distribution for the perfectly transmitting eigenchannel. Our approach also allows to predict the intensity profile of such channel in a disordered slab with open boundaries, pointing to the possibility of controllable delivery of light to different depths with local illumination.Comment: 9 pages, 6 figure

    Critical States Embedded in the Continuum

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    We introduce a class of critical states which are embedded in the continuum (CSC) of one-dimensional optical waveguide array with one non-Hermitian defect. These states are at the verge of being fractal and have real propagation constant. They emerge at a phase transition which is driven by the imaginary refractive index of the defect waveguide and it is accompanied by a mode segregation which reveals analogies with the Dicke super -radiance. Below this point the states are extended while above they evolve to exponentially localized modes. An addition of a background gain or loss can turn these localized states to bound states in the continuum.Comment: 4.5 pages, 3 figures, 1 page of supplementary material including one figur

    Daily antigen testing to reduce disruption when schools return

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    Identification of Novel Glial Genes by Single-Cell Transcriptional Profiling of Bergmann Glial Cells from Mouse Cerebellum

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    Bergmann glial cells play critical roles in the structure and function of the cerebellum. During development, their radial processes serve as guides for migrating granule neurons and their terminal endfeet tile to form the glia limitans. As the cerebellum matures, Bergmann glia perform important roles in synaptic transmission and synapse maintenance, while continuing to serve as essential structural elements. Despite growing evidence of the diverse functions of Bergmann glia, the molecular mechanisms that mediate these functions have remained largely unknown. As a step toward identifying the molecular repertoire underlying Bergmann glial function, here we examine global gene expression in individual Bergmann glia from developing (P6) and mature (P30) mouse cerebellum. When we select for developmentally regulated genes, we find that transcription factors and ribosomal genes are particularly enriched at P6 relative to P30; whereas synapse associated molecules are enriched at P30 relative to P6. We also analyze genes expressed at high levels at both ages. In all these categories, we find genes that were not previously known to be expressed in glial cells, and discuss novel functions some of these genes may potentially play in Bergmann glia. We also show that Bergmann glia, even in the adult, express a large set of genes thought to be specific to stem cells, suggesting that Bergmann glia may retain neural precursor potential as has been proposed. Finally, we highlight several genes that in the cerebellum are expressed in Bergmann glia but not astrocytes, and may therefore serve as new, specific markers for Bergmann glia

    Ordinal Regression Analysis: Predicting Mathematics Proficiency Using the Continuation Ratio Model

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    One commonly used model to analyze ordinal response data is the proportional odds (PO) model. However, if research interest is focused on a particular category and if an individual must pass through lower categories before achieving a higher level, the continuation ratio (CR) model is a more appropriate choice than the PO model. In addition, statistical software, such as Stata and SAS, may use different techniques to estimate the parameters. The CR model is used to illustrate the analysis of ordinal data in education using Stata and SAS and compares the results of fitting the CR model between these two packages

    Traditional Healers and Mental Health in Nepal: A Scoping Review.

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    Despite extensive ethnographic and qualitative research on traditional healers in Nepal, the role of traditional healers in relation to mental health has not been synthesized. We focused on the following clinically based research question, "What are the processes by which Nepali traditional healers address mental well-being?" We adopted a scoping review methodology to maximize the available literature base and conducted a modified thematic analysis rooted in grounded theory, ethnography, and phenomenology. We searched five databases using terms related to traditional healers and mental health. We contacted key authors and reviewed references for additional literature. Our scoping review yielded 86 eligible studies, 65 of which relied solely on classical qualitative study designs. The reviewed literature suggests that traditional healers use a wide range of interventions that utilize magico-religious explanatory models to invoke symbolic transference, manipulation of local illness narratives, roles, and relationships, cognitive restructuring, meaning-making, and catharsis. Traditional healers' perceived impact appears greatest for mild to moderate forms of psychological distress. However, the methodological and sample heterogeneity preclude uniform conclusions about traditional healing. Further research should employ methods which are both empirically sound and culturally adapted to explore the role of traditional healers in mental health

    Effects of Row Spacings and Varieties on Grain Yield and Economics of Maize

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    Maize is the second most important crop of Nepal. The yield of the crop is low due to lack of appropriate plant density for the varieties. The field experiment was carried out to study the effect of different row spacings on different maize varieties at Deupur, Lamahi municipality of the dang district in province No. 5, Nepal during the rainy season from June to September, 2018. Four levels of spacings (boardcasting and three row spacings of 45, 60 and 75 cm) and two maize varieties (Rampur Composite and Arun-2) were evaluated using randomized complete block design with three replications. The highest grain yield was found in Rampur Composite and Arun-2 while they were planted with row spacing of 60 cm with plant to plant spacing of 25 cm. The highest grain yield, cob length, cob circumference, number of rows per cob, thousand grain weight  were reported when maize was planted in the  row spacing 60Γ—25cm. Among the maize varieties, Rampur Composite produced the highest grain yield, cob length, cob circumference, number of rows per cob as compared to Arun-2. This study suggested that maize production can be maximized by cultivating maize varieties with row spacing of 60 cm with plant to plant spacing of 25 cm

    Surgical management of hepatic hydatid cyst in children

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    The aim of this study was to demonstrate the surgical treatment and outcome of hydatid cyst in liver in children. The age of presentation varied from 8-11 years. All patients had abdominal pain, five had lump in right hypochondrium and three patients had fever. Hydatid cyst serology, indirect hemaglutination test, ultrasonography and CT scan done in all the patients. Histological examination supported the diagnosis of hydatidosis since the cyst wall contains outer laminated and inner germinal layer. All the patients got relief of their preoperative symptoms after surgery. Two patients had positive serology after surgery. Therefore, they were given two additional regimen of albendazole and turned out to be serologically negative. In conclusion, hydatid cyst management in children is not consensual. However, conservative surgery remains the treatment of choice to avoid serious complication in the endemic region of Indian subcontinent

    Surgical management of hepatic hydatid cyst in children

    Get PDF
    The aim of this study was to demonstrate the surgical treatment and outcome of hydatid cyst in liver in children. The age of presentation varied from 8-11 years. All patients had abdominal pain, five had lump in right hypochondrium and three patients had fever. Hydatid cyst serology, indirect hemaglutination test, ultrasonography and CT scan done in all the patients. Histological examination supported the diagnosis of hydatidosis since the cyst wall contains outer laminated and inner germinal layer. All the patients got relief of their preoperative symptoms after surgery. Two patients had positive serology after surgery. Therefore, they were given two additional regimen of albendazole and turned out to be serologically negative. In conclusion, hydatid cyst management in children is not consensual. However, conservative surgery remains the treatment of choice to avoid serious complication in the endemic region of Indian subcontinent
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