459 research outputs found

    Mode Confinement in Photonic Quasi-Crystal Point-Defect Cavities for Particle Accelerators

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    In this Letter, we present a study of the confinement properties of point-defect resonators in finite-size photonic-bandgap structures composed of aperiodic arrangements of dielectric rods, with special emphasis on their use for the design of cavities for particle accelerators. Specifically, for representative geometries, we study the properties of the fundamental mode (as a function of the filling fraction, structure size, and losses) via 2-D and 3-D full-wave numerical simulations, as well as microwave measurements at room temperature. Results indicate that, for reduced-size structures, aperiodic geometries exhibit superior confinement properties by comparison with periodic ones.Comment: 4 pages, 4 figures, accepted for publication in Applied Physics Letter

    Elaboración de estándares para evaluar una competencia : un ejemplo aplicado a la interpretación de las fórmulas químicas

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    La evaluación por competencias es entendida como la capacidad de realización situada y afectada por el contexto en el que se desenvuelve el sujeto. Este enfoque requiere modificar concepciones y prácticas muy arraigadas. Al cursar Química, una competencia que los alumnos deben alcanzar se refiere al aprendizaje y la comprensión del lenguaje de la Química. En este dominio, una fórmula química emplea para su escritura dos sistemas de símbolos, el alfabeto y los números arábigos, pero siguiendo reglas diferentes al del uso en la vida cotidiana (comunicación verbal y matemática). En este trabajo nos proponemos reconocer algunos de los significados que las fórmulas tienen para los alumnos que inician el cursado de la asignatura, esto nos permitirá identificar estándares que ayudarán a definir en que nivel de competencia respecto del lenguaje químico se encuentran los alumnos

    Hybrid photonic-bandgap accelerating cavities

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    In a recent investigation, we studied two-dimensional point-defected photonic bandgap cavities composed of dielectric rods arranged according to various representative periodic and aperiodic lattices, with special emphasis on possible applications to particle acceleration (along the longitudinal axis). In this paper, we present a new study aimed at highlighting the possible advantages of using hybrid structures based on the above dielectric configurations, but featuring metallic rods in the outermost regions, for the design of extremely-high quality factor, bandgap-based, accelerating resonators. In this framework, we consider diverse configurations, with different (periodic and aperiodic) lattice geometries, sizes, and dielectric/metal fractions. Moreover, we also explore possible improvements attainable via the use of superconducting plates to confine the electromagnetic field in the longitudinal direction. Results from our comparative studies, based on numerical full-wave simulations backed by experimental validations (at room and cryogenic temperatures) in the microwave region, identify the candidate parametric configurations capable of yielding the highest quality factor.Comment: 13 pages, 5 figures, 3 tables. One figure and one reference added; minor changes in the tex

    Partial purification and MALDI-TOF MS analysis of UN1, a tumor antigen membrane glycoprotein.

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    UN1 is a membrane glycoprotein that is expressed in immature human thymocytes, a subpopulation of peripheral T lymphocytes, the HPB acute lymphoblastic leukemia (ALL) T-cell line and fetal thymus. We previously reported the isolation of a monoclonal antibody (UN1 mAb) recognizing the UN1 protein that was classified as "unclustered" at the 5th and 6th International Workshop and Conference on Human Leukocyte Differentiation Antigens. UN1 was highly expressed in breast cancer tissues and was undetected in non-proliferative lesions and in normal breast tissues, indicating a role for UN1 in the development of a tumorigenic phenotype of breast cancer cells. In this study, we report a partial purification of the UN1 protein from HPB-ALL T cells by anion-exchange chromatography followed by immunoprecipitation with the UN1 mAb and MALDI-TOF MS analysis. This analysis should assist in identifying the amino acid sequence of UN

    Semantically selective augmentation for deep compact person re-identification

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    We present a deep person re-identification approach that combines semantically selective, deep data augmentation with clustering-based network compression to generate high performance, light and fast inference networks. In particular, we propose to augment limited training data via sampling from a deep convolutional generative adversarial network (DCGAN), whose discriminator is constrained by a semantic classifier to explicitly control the domain specificity of the generation process. Thereby, we encode information in the classifier network which can be utilized to steer adversarial synthesis, and which fuels our CondenseNet ID-network training. We provide a quantitative and qualitative analysis of the approach and its variants on a number of datasets, obtaining results that outperform the state-of-the-art on the LIMA dataset for long-term monitoring in indoor living spaces

    Comment: Superconducting transition in Nb nanowires fabricated using focused ion beam

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    In a recent paper Tettamanzi et al (2009 Nanotechnology \bf{20} 465302) describe the fabrication of superconducting Nb nanowires using a focused ion beam. They interpret their conductivity data in the framework of thermal and quantum phase slips below TcT_c. In the following we will argue that their analysis is inappropriate and incomplete, leading to contradictory results. Instead, we propose an interpretation of the data within a SN proximity model.Comment: 3 pages, 1 figure accepted in Nanotechnolog

    Direct interation of garcinol and related polyisoprenylated benzophenones of Garcinia cambogia fruits with the transcription factor STAT-1 as a likely mechanism of their inhibitory effect on cytokine signaling pathways.

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    Garcinol (1), a polyisoprenylated benzophenone occurring in Garcinia species, has been reported to exert anti-inflammatory activity in LPS-stimulated macrophages, through inhibition of NF-κB and/or JAK/STAT-1 activation. In order to provide deeper insight into its effects on the cytokine signaling pathway and to clarify the underlying molecular mechanisms, 1 was isolated from the fruits of Garcinia cambogia along with two other polyisoprenylated benzophenones, guttiferones K (2) and guttiferone M (3), differing from each other in their isoprenyl moieties and their positions on the benzophenone core. The affinities of 1-3 for the STAT-1 protein have been evaluated by surface plasmon resonance and molecular docking studies and resulted in KD values in the micromolar range. Consistent with the observed high affinity toward the STAT-1 protein, garcinol and guttiferones K and M were able to modulate cytokine signaling in different cultured cell lines, mainly by inhibiting STAT-1 nuclear transfer and DNA binding, as assessed by an electrophorectic mobility shift assay

    Surgery versus stereotactic radiotherapy for treatment of pulmonary metastases. A systematic review of literature

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    It is not clear as to which is the best treatment among surgery and stereotactic radiotherapy (SBRT) for lung oligometastases. A systematic review of literature with a priori selection criteria was conducted on articles on the treatment of pulmonary metastases with surgery or SBRT. Only original articles with a population of patients of more than 50 were selected. After final selection, 61 articles on surgical treatment and 18 on SBRT were included. No difference was encountered in short-term survival between pulmonary metastasectomy and SBRT. In the long-term surgery seems to guarantee better survival rates. Mortality and morbidity after treatment are 0-4.7% and 0-23% for surgery, and 0-2% and 4-31% for SBRT. Surgical metastasectomy remains the treatment of choice for pulmonary oligometastases. Patients with metastatic cancer with a limited number of deposits may benefit from surgical removal or irradiation of tumor nodules in addiction to chemotherapy. Surgical resection has been demonstrated to improve survival and, in some cases, can be curative. Stereotactic radiotherapy is emerging as a less invasive alternative to surgery, but settings and implications of the two treatments are profoundly different. The two techniques show similar results in the short-term, with lower complications rates for radiotherapy, while in the long-term surgery seems to guarantee higher survival rates
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