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Measuring $CP$ violation and mixing in charm with inclusive self-conjugate multibody decay modes  [PDF]
S. Malde,C. Thomas,G. Wilkinson
Physics , 2015, DOI: 10.1103/PhysRevD.91.094032
Abstract: Time-dependent studies of inclusive charm decays to multibody self-conjugate final states can be used to determine the indirect $CP$-violating observable $A_\Gamma$ and the mixing observable $y_{CP}$, provided that the fractional $CP$-even content of the final state, $F_+$, is known. This approach can yield significantly improved sensitivity compared with the conventional method that relies on decays to $CP$ eigenstates. In particular, $D \to \pi^+\pi^-\pi^0$ appears to be an especially powerful channel, given its relatively large branching fraction and the high value of $F_+$ that has recently been measured at charm threshold.
A Self-Referencing Intensity Based Polymer Optical Fiber Sensor for Liquid Detection  [PDF]
David Sánchez Montero,Carmen Vázquez,Ingo M?llers,Jon Arrúe,Dieter J?ger
Sensors , 2009, DOI: 10.3390/s90806446
Abstract: A novel self-referencing fiber optic intensity sensor based on bending losses of a partially polished polymer optical fiber (POF) coupler is presented. The coupling ratio (K) depends on the external liquid in which the sensor is immersed. It is possible to distinguish between different liquids and to detect their presence. Experimental results for the most usual liquids found in industry, like water and oil, are given. K value increases up to 10% from the nominal value depending on the liquid. Sensor temperature dependence has also been studied for a range from 25 oC (environmental condition) to 50 oC. Any sector requiring liquid level measurements in flammable atmospheres can benefit from this intrinsically safe technology.
Proposal for absolute CEP measurement using 0-to-f self-referencing  [PDF]
S. B. P. Radnor,P. Kinsler,G. H. C. New
Physics , 2009,
Abstract: We show how to adapt a 0-f self-referencing technique to provide a single shot absolute Carrier Envelope Phase (CEP) measurement by using the CEP reference provided by difference frequency generation (DFG) between the spectral wings of the fundamental pulse. Usually, the beat between the input pulse and the DFG signal then provides feedback with which to stabilize the CEP slip in a pulse train. However, with a simple extension we can get a single shot absolute CEP measurement. Success relies on having well characterized input pulses, and the use of accurate propagation models through the nonlinear crystal -- these enable us to construct a mapping between the experimental measurement and the CEP of the optical pulse.
Self-referencing a continuous-wave laser with electro-optic modulation  [PDF]
Katja Beha,Daniel C. Cole,Pascal Del'Haye,Aurélien Coillet,Scott A. Diddams,Scott B. Papp
Physics , 2015,
Abstract: We phase-coherently measure the frequency of continuous-wave (CW) laser light by use of optical-phase modulation and f-2f nonlinear interferometry. Periodic electro-optic modulation (EOM) transforms the CW laser into a continuous train of picosecond optical pulses. Subsequent nonlinear-fiber broadening of this EOM frequency comb produces a supercontinuum with 160 THz of bandwidth. A critical intermediate step is optical filtering of the EOM comb to reduce electronic-noise-induced decoherence of the supercontinuum. Applying f-2f self-referencing with the supercontinuum yields the carrier-envelope offset frequency of the EOM comb, which is precisely the difference of the CW laser frequency and an exact integer multiple of the EOM pulse repetition rate. Here we demonstrate absolute optical frequency metrology and synthesis applications of the self-referenced CW laser with <5E-14 fractional accuracy and stability.
A Self-Referencing Detection of Microorganisms Using Surface Enhanced Raman Scattering Nanoprobes in a Test-in-a-Tube Platform  [PDF]
Nan Xiao,Chao Wang,Chenxu Yu
Biosensors , 2013, DOI: 10.3390/bios3030312
Abstract: Anisotropic nanoparticles ( i.e., silver nanocubes) were functionalized with target-specific antibodies and Raman active tags to serve as nanoprobes for the rapid detection of bacteria in a test-in-a-tube platform. A self-referencing scheme was developed and implemented in which surface enhanced Raman spectroscopic (SERS) signatures of the targets were observed superimposed with the SERS signals of the Raman tags. The assessment through the dual signals (superimposed target and tag Raman signatures) supported a specific recognition of the targets in a single step with no washing/separation needed to a sensitivity of 10 2 CFU/mL, even in the presence of non-target bacteria at a 10 times higher concentration. The self-referencing protocol implemented with a portable Raman spectrometer potentially can become an easy-to-use, field-deployable spectroscopic sensor for onsite detection of pathogenic microorganisms.
Referencing: Principles, Practice and Problems
Colin Neville
RGUHS Journal of Pharmaceutical Sciences , 2012,
Abstract: This paper explores a neglected aspect of academic writing, namely the principles and practice of referencing sources. In recent years, plagiarism has been a dominant concern for higher education practitioners. However, there can be a fine line between plagiarism and poor referencing practice, and higher education institutions report that students often struggle to understand, not just the ‘how’, but the ‘when’ and ‘why’ aspects of referencing. This paper will, however, assert that student difficulties can stem from the inconsistencies of institutional advice, proliferation of referencing styles, and an over-emphasis by institutions on the technical presentation of sources, rather than on the principles underpinning referencing. The author will argue that academic writers, particularly students, should be encouraged by institutions to perceive referencing primarily as a tool for the development of an authentic authorial voice, rather than just as a defensive shield against accusations of plagiarism.
Self-Referencing Method for Relative Color Intensity Analysis Using Mobile-Phone  [PDF]
Wellington S. Souza, Marcos A. S. de Oliveira, Gabrielli M. F. de Oliveira, Dalton P. de Santana, Renato E. de Araujo
Optics and Photonics Journal (OPJ) , 2018, DOI: 10.4236/opj.2018.87022
Abstract: Mobile-phones have been widely explored on colorimetric evaluations. However, their use with different built-in image systems and acquisition configuration, in an environment with non-controlled illumination, limits the establishment of an accurate color analysis. To overcome this restriction, the determination of the absolute color of an object can be overlooked and a relative color value determined. In this work, we establish a new approach for spectroscopic evaluation based on cell-phone imaging, with no previous calibration, determining relative color values. The standalone relative color intensity method is evaluated under the use of four distinct mobile-phones and different illumination conditions. The capability to distinguish different color shades exploring the proposed self-referenced relative color intensity technique is appraised. Moreover, the potential use of the method is demonstrated by evaluating the chemical-adsorption process of Cysteamine molecules on gold nanoparticle surfaces. The proposed self-referenced technique can improve and expand the use of mobile-phones in spectroscopic applications.
Optimal Self-Organization  [PDF]
Dirk Helbing,Tamas Vicsek
Physics , 1999, DOI: 10.1088/1367-2630/1/1/313
Abstract: We present computational and analytical results indicating that systems of driven entities with repulsive interactions tend to reach an optimal state associated with minimal interaction and minimal dissipation. Using concepts from non-equilibrium thermodynamics and game theoretical ideas, we generalize this finding to an even wider class of self-organizing systems which have the ability to reach a state of maximal overall ``success''. This principle is expected to be relevant for driven systems in physics like sheared granular media, but it is also applicable to biological, social, and economic systems, for which only a limited number of quantitative principles are available yet.
Single-Shot 60 dB Dynamic Range Laser Contrast Measurement Using Self-Referencing Spectral Interferometry  [PDF]
Sasi Palaniyappan,R. P. Johnson,T. Shimada,R. C. Shah,D. Jung,D. C. Gautier,B. M. Hegelich,J. C. Fernandez
Physics , 2012,
Abstract: High dynamic range contrast measurement of laser pulses is typically obtained by cross-correlating the laser pulse with a self-generated reference laser pulse directly in the temporal domain. Alternatively, it is also possible to measure the spectral interferogram of the laser pulse with the references pulse in the spectral domain, from which the high dynamic range contrast measurement can be extracted using inverse Fourier-transformation. Here, we demonstrate single-shot 60 dB dynamic range laser contrast measurement by inverse Fourier-transforming the measured spectral interferogram into temporal domain. The result directly provides the cross-correlation of the laser pulse with the reference pulse provided there is enough time-delay imposed between the laser and reference pulses. Then method is cross-calibrated by measuring known pre-pulses along with scanning third-order auto-correlator measurements.
Self-referencing cellular automata: A model of the evolution of information control in biological systems  [PDF]
Theodore P. Pavlic,Alyssa M. Adams,Paul C. W. Davies,Sara Imari Walker
Physics , 2014, DOI: 10.7551/978-0-262-32621-6-ch083
Abstract: Cellular automata have been useful artificial models for exploring how relatively simple rules combined with spatial memory can give rise to complex emergent patterns. Moreover, studying the dynamics of how rules emerge under artificial selection for function has recently become a powerful tool for understanding how evolution can innovate within its genetic rule space. However, conventional cellular automata lack the kind of state feedback that is surely present in natural evolving systems. Each new generation of a population leaves an indelible mark on its environment and thus affects the selective pressures that shape future generations of that population. To model this phenomenon, we have augmented traditional cellular automata with state-dependent feedback. Rather than generating automata executions from an initial condition and a static rule, we introduce mappings which generate iteration rules from the cellular automaton itself. We show that these new automata contain disconnected regions which locally act like conventional automata, thus encapsulating multiple functions into one structure. Consequently, we have provided a new model for processes like cell differentiation. Finally, by studying the size of these regions, we provide additional evidence that the dynamics of self-reference may be critical to understanding the evolution of natural language. In particular, the rules of elementary cellular automata appear to be distributed in the same way as words in the corpus of a natural language.
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