4,192 research outputs found

    Measurements of CP-Violating Asymmetries in B0 to a1(1260)^{+-} pi^{-+} Decays

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    We present measurements of CP-violating asymmetries in the decay B0 -> a_1(1260)^{+-} pi^{-+} with a_1(1260)^{+-} -> pi^{-+} pi^{+-} pi^{+-}. The data sample corresponds to 384 million B B-bar pairs collected with the BaBar detector at the PEP-II asymmetric B-factory at SLAC. We measure the CP-violating asymmetry A^{a1pi}_{CP}=-0.07+-0.07+-0.02, the mixing-induced CP violation parameter S_{a1pi}= 0.37 +-0.21+-0.07, the direct CP violation parameter C_{a1pi}=-0.10+-0.15+-0.09, and the parameters DeltaC_{a1pi}=0.26+-0.15+-0.07 and DeltaS_{a1pi}=-0.14+-0.21+-0.06. From these measured quantities we exstract the angle alpha_{eff}= 78.6^{0} +- 7.3^{0}.Comment: 4 pages, 2 postscript figures Invited talk at the 4th International Workshop on the CKM Unitary Triangle, 12/12/2006 - 16/12/2006, Nagoya, Japa

    Finding a reflexive voice : -- researching the problems of implementing new learning practices within a New Zealand manufacturing organisation : a 100pt thesis presented in partial fulfilment of the requirements for the degree of Master of Management in Human Resources Management at Massey University

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    This study explored the social forces mediating manager's participation in a new reflexive participative learning practice designed to improve profitability within a New Zealand manufacturing organisation. Despite a large theoretical and managerial body of literature on organisational learning there has been little empirical investigation of how people experience and engage their reflexivity towards challenging the status-quo to create high level learning and new knowledge. Power was identified as a potential moderator of the reflexive learning experience and the variable relations of power and learning were constructed from a review of literature and these relationships were explored and investigated within the case study. Two prevailing discourses were identified as powerful moderators of public reflexivity, the traditionalist discourse which constructed managers actions and conversations towards insularism and survivalist concerns and the productionist discourse in which institutionalised production practices encircled and mediated managers actions and what constituted legitimacy in conversations. This study used a critical action research method to place the reflexive experience of managers and the researcher at the centre of the study and provide data representative of the social discourses that constructed variable freedoms and constraints upon the reflexive voice

    Therapeutic implications of immunogenic cell death in human cancer

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    Dendritic cells (DCs) are central to the adoptive immune response, and their function is regulated by diverse signals in a context-specific manner. Different DCs have been described in physiologic conditions, inflammation, and cancer, prompting a series of questions on how adoptive immune responses, or tolerance, develop against tumors. Increasing evidence suggests that tumor treatments induce a dramatic change on tumor-infiltrating lymphocytes and, in particular, on some DC subtypes. In this review, we summarize the latest evidence on the role of DCs in cancer and preliminary evidence on chemotherapy-associated antigens identified in human cancers

    Brillouin-Raman mapping of natural fibers with spectral moment analysis

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    This is the author accepted manuscript. The final version is available from the Optical Society of America via the DOI in this record.Brillouin spectroscopy has emerged as a novel analytical tool for biophotonic research and applications. It operates on a microscopic scale and in the GHz spectral range, providing a new spatial and frequency window for the analysis of the structure and elasticity of materials. Here we investigate spectral moments calculation as a means of analysing Brillouin and Raman spectra, providing rapid access to peak intensity and frequency shift, with robust application to fast scanning measurements. This work demonstrates the potential of the method, especially in the case of micro-structured samples, typical of bio-medical applications.COST (European Cooperation in Science and Technology

    Brillouin Light Scattering Microspectroscopy for Biomedical Research and Applications: introduction to feature issue

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    This is the final version. Available from Optical Society of America via the DOI in this repcord.There has been a marked revival of interest in brillouin light scattering spectroscopy/microscopy over the last decade in regards to applications related to all optically studying the mechanical problems associated with systems of biological and medical interest. This revival has been driven by advancements in spectrometer design, together with mounting evidence of the critical role that mechanical properties can play in biological processes as well as the onset of diverse diseases. This feature issue contains a series of papers spanning some of the latest developments in the field of Brillouin light scattering spectroscopy and microscopy as applied to systems of biomedical interest

    Image analysis applied to Brillouin images of tissue-mimicking collagen gelatins

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    This is the final version. Available on open access from Optical Society of America via the DOI in this recordBrillouin spectroscopy is an emerging analytical tool in biomedical and biophysical sciences. It probes viscoelasticity through the propagation of thermally induced acoustic waves at gigahertz frequencies. Brillouin light scattering (BLS) measurements have traditionally been performed using multipass Fabry-Pérot interferometers, which have high contrast and resolution, however as they are scanning spectrometers they often require long acquisition times at low laser powers. In the last decade, a new concept of Brillouin spectrometer has emerged, making use of highly angle-dispersive Virtually Imaged Phase Array (VIPA) etalons, which enable fast acquisition times for minimally turbid materials, when high contrast is not imperative. The ability to acquire Brillouin spectra rapidly, together with long term system stability, make this system a viable candidate for use in biomedical applications, especially to probe live cells and tissues. While various methods are being developed to improve system contrast and speed, little work has been published discussing the details of imaging data analysis and spectral processing. Here we present a method that we developed for the automated retrieval of Brillouin line shape parameters from imaging datasets acquired with a dual-stage VIPA Brillouin microscope. We applied this method for the first time to BLS measurements of collagen gelatin hydrogels at different hydration levels and cross-linker concentrations. This work demonstrates that it is possible to obtain the relevant information from Brillouin spectra using software for real-time high-accuracy analysis.Engineering and Physical Sciences Research Council (EPSRC)Cancer Research U

    Cold and Hot Spots: from Inhibition to Enhancement by Nanoscale Phase Tuning of Optical Nanoantennas

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    Optical nanoantennas are well-known for the confinement of light into nanoscale hot spots, suitable for emission enhancement and sensing applications. Here, we show how control of the antenna dimensions allows tuning the local optical phase, hence turning a hot spot into a cold spot. We manipulate the local intensity exploiting the interference between driving and scattered field. Using single molecules as local detectors, we experimentally show the creation of subwavelength pockets with full suppression of the driving field. Remarkably, together with the cold excitation spots, we observe inhibition of emission by the phase-tuned nanoantenna. The fluorescence lifetime of a molecule scanned in such volumes becomes longer, showing slow down of spontaneous decay. In conclusion, the spatial phase of a nanoantenna is a powerful knob to tune between enhancement and inhibition in a 3-dimensional subwavelength volume.Peer ReviewedPostprint (author's final draft

    Subwavelength hyperspectral THz studies of articular cartilage

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    This is the final version of the article. Available from the publisher via the DOI in this record.Terahertz-spectroscopy probes dynamics and spectral response of collective vibrational modes in condensed phase, which can yield insight into composition and topology. However, due to the long wavelengths employed (λ = 300 μm at 1THz), diffraction limited imaging is typically restricted to spatial resolutions around a millimeter. Here, we demonstrate a new form of subwavelength hyperspectral, polarization-resolved THz imaging which employs an optical pattern projected onto a 6 μm-thin silicon wafer to achieve near-field modulation of a co-incident THz pulse. By placing near-field scatterers, one can measure the interaction of object with the evanescent THz fields. Further, by measuring the temporal evolution of the THz field a sample's permittivity can be extracted with 65 μm spatial resolution due to the presence of evanescent fields. Here, we present the first application of this new approach to articular cartilage. We show that the THz permittivity in this material varies progressively from the superficial zone to the deep layer, and that this correlates with a change in orientation of the collagen fibrils that compose the extracellular matrix (ECM) of the tissue. Our approach enables direct interrogation of the sample's biophysical properties, in this case concerning the structure and permittivity of collagen fibrils and their anisotropic organisation in connective tissue.The research presented in this work was funded by QinetiQ & EPSRC under iCase award 12440575 and grant number EP/K041215/1

    The Correlation Between Historical and Instrumental Seismicity in the Sansepolcro Basin, Northern Apennines, Italy

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    The area investigated, the Sansepolcro basin, is characterized by the presence of important earthquakes in the past with estimated intensity even larger than IX MCS (the 1352 Monterchi earthquake, the 1389 Boccaserriola, the 1458 Citta’ di Castello, the 1781 Cagliese and the 1917 Monterchi-Citerna earthquakes, CPTI Working Group, 2004) and by a surprisingly scarce instrumental seismicity compared to the adjacent areas struck by high seismicity (Castello et al., 2005; Ciaccio et al., 2006). The area north of Sansepolcro has been struck in recent years by four minor sequences, occurred between 1987 and 2001 with magnitude ranging from Ml3.0 to Mw4.7. In this work we analyse the most important earthquakes of the 20th century occurred in the Altotiberina Valley in 1917, 1918, 1919 and 1948; in particular instrumental relocation, focal mechanisms and Ms and Mw magnitude estimation are re-evaluated. The relocation of these earthquakes is particularly critical and is an important issue. An instrumental and precise location is critical for the complexity of the problems associated with the study of seismograms prior to the first half of the twentieth century and is relevant because in the surrounding regions higher seismicity is observed. Regarding this peculiarity of the area, it’s very important to detect the location of the historical earthquakes: in particular, the 1917 event is often associated to the possibility that the regional low angle Altotiberina Fault (Barchi et al., 1998) is able or not to nucleate large- or moderate-magnitude events, being historically located close to its surface (Boncio and Lavecchia, 2000)

    Historical and Instrumental Seismicity of the Sansepolcro Basin, Northern Apennines, Italy

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    In this work we analyse the most important earthquakes of the 20th century occurred in the Altotiberina Valley in 1917, 1918, 1919 and 1948; in particular instrumental relocation and Ms magnitude estimation are re-evaluated. The area investigated, the Sansepolcro basin, is characterized by the presence of important earthquakes in the past with estimated intensity even larger than IX MCS (the 1352 Monterchi earthquake, the 1389 Boccaserriola, the 1458 Citta' di Castello, the 1781 Cagliese and the 1917 Monterchi-Citerna earthquakes, CPTI Working Group, 2004) and by a surprisingly scarce instrumental seismicity compared to the adjacent areas struck by high seismicity (Castello et al., 2005; Ciaccio et al., 2006). In particular, the area north of Sansepolcro has been struck in recent years by four minor sequences, occurred between 1987 and 2001 with magnitude ranging from Ml3.0 to Mw4.7. The relocation of these earthquakes is particularly critical and in an important issue. An instrumental and precise location is critical for the complexity of the problems associated with the study of seismograms prior to the rst half of the twentieth century and is relevant because in the surrounding regions higher seismicity is observed. Regarding this peculiarity of the area, it’s very important to detect the localization of the historical earthquakes: in particular, the 1917 event is often associated to the possibility that the regional low angle Altotiberina Fault (Barchi et al., 1998) is able or not to nucleate large- or moderate-magnitude events, being historically located close to its surface (Boncio and Lavecchia, 2000)
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