Effective Dynamic Range in Measurements with Flash Analog-to-Digital Convertor

Flash Analog to Digital Convertor (FADC) is frequently used in nuclear and particle physics experiments, often as the major component in big multi-channel systems. The large data volume makes the optimization of operating parameters necessary. This article reports a study of a method to extend the dynamic range of an 8-bit FADC from the nominal $\rm{2^8}$ value. By comparing the integrated pulse area with that of a reference profile, good energy reconstruction and event identification can be achieved on saturated events from CsI(Tl) crystal scintillators. The effective dynamic range can be extended by at least 4 more bits. The algorithm is generic and is expected to be applicable to other detector systems with FADC readout.Comment: 19 pages, 1 table, 10 figure

Can the Zee Model Explain the Observed Neutrino Data?

The eigenvalues and mixing angles in the Zee model are investigated parameter-independently. When we require |\Delta m^2_{12}/\Delta m^2_{23}| \ll 1 in order to understand the solar and atmospheric data simultaneously, the only solution is one which gives bi-maximal mixing. It is pointed out that the observed values \sin^2 2\theta_{solar} \simeq 0.66 in the MSW LMA solution cannot be explained within the framework of the Zee model, because we derive a severe constraint on the value of \sin^2 2 \theta_{solar}, \sin^2 2 \theta_{solar} \geq 1 -(1/16)(\Delta m^2_{solar}/\Delta m^2_{atm})^2.Comment: Latex file, 10 pages, 1 figure, explanations and references added, typos corrected, to be published in Phys.Rev.

On Optimizing Locally Linear Nearest Neighbour Reconstructions Using Prototype Reduction Schemes

This paper concerns the use of Prototype Reduction Schemes (PRS) to optimize the computations involved in typical k-Nearest Neighbor (k-NN) rules. These rules have been successfully used for decades in statistical Pattern Recognition (PR) applications, and have numerous applications because of their known error bounds. For a given data point of unknown identity, the k-NN possesses the phenomenon that it combines the information about the samples from a priori target classes (values) of selected neighbors to, for example, predict the target class of the tested sample. Recently, an implementation of the k-NN, named as the Locally Linear Reconstruction (LLR) [11], has been proposed. The salient feature of the latter is that by invoking a quadratic optimization process, it is capable of systematically setting model parameters, such as the number of neighbors (specified by the parameter, k) and the weights. However, the LLR takes more time than other conventional methods when it has to be applied to classification tasks. To overcome this problem, we propose a strategy of using a PRS to efficiently compute the optimization problem. In this paper, we demonstrate, first of all, that by completely discarding the points not included by the PRS, we can obtain a reduced set of sample points, using which, in turn, the quadratic optimization problem can be computed far more expediently. The values of the corresponding indices are comparable to those obtained with the original training set (i.e., the one which considers all the data points) even though the computations required to obtain the prototypes and the corresponding classification accuracies are noticeably less. The proposed method has been tested on artificial and real-life data sets, and the results obtained are very promising, and has potential in PR applications

Phenomenological Consequences of Singlet Neutrinos

In this paper, we study the phenomenology of right-handed neutrino isosinglets. We consider the general situation where the neutrino masses are not necessarily given by $m_D^2/M$, where $m_D$ and $M$ are the Dirac and Majorana mass terms respectively. The consequent mixing between the light and heavy neutrinos is then not suppressed, and we treat it as an independent parameter in the analysis. It turns out that $\mu-e$ conversion is an important experiment in placing limits on the heavy mass scale ($M$) and the mixing. Mixings among light neutrinos are constrained by neutrinoless double beta decay, as well as by solar and atmospheric neutrino experiments. Detailed one-loop calculations for lepton number violating vertices are provided.Comment: Revtex file,TRI-PP-94-1,VPI-IHEP-94-1, 23 pages, a compressed for 8 figures is appende

A sensitive bithiophene-based biosensor for interferon-gamma characterization and analysis

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Biomarker-guided sequential targeted therapies to overcome therapy resistance in rapidly evolving highly aggressive mammary tumors

Combinatorial targeted therapies are more effective in treating cancer by blocking by-pass mechanisms or inducing synthetic lethality. However, their clinical application is hampered by resistance and toxicity. To meet this important challenge, we developed and tested a novel concept of biomarker-guided sequential applications of various targeted therapies using ErbB2-overexpressing/PTEN-low, highly aggressive breast cancer as our model. Strikingly, sustained activation of ErbB2 and downstream pathways drives trastuzumab resistance in both PTEN-low/trastuzumab-resistant breast cancers from patients and mammary tumors with intratumoral heterogeneity from genetically-engineered mice. Although lapatinib initially inhibited trastuzumab-resistant mouse tumors, tumors by-passed the inhibition by activating the PI3K/mTOR signaling network as shown by the quantitative protein arrays. Interestingly, activation of the mTOR pathway was also observed in neoadjuvant lapatinib-treated patients manifesting lapatinib resistance. Trastuzumab + lapatinib resistance was effectively overcome by sequential application of a PI3K/mTOR dual kinase inhibitor (BEZ235) with no significant toxicity. However, our p-RTK array analysis demonstrated that BEZ235 treatment led to increased ErbB2 expression and phosphorylation in genetically-engineered mouse tumors and in 3-D, but not 2-D, culture, leading to BEZ235 resistance. Mechanistically, we identified ErbB2 protein stabilization and activation as a novel mechanism of BEZ235 resistance, which was reversed by subsequent treatment with lapatinib + BEZ235 combination. Remarkably, this sequential application of targeted therapies guided by biomarker changes in the tumors rapidly evolving resistance doubled the life-span of mice bearing exceedingly aggressive tumors. This fundamentally novel approach of using targeted therapies in a sequential order can effectively target and reprogram the signaling networks in cancers evolving resistance during treatment. © 2014 IBCB, SIBS, CAS All rights reserved

Constraints On Radiative Neutrino Mass Models From Oscillation Data

The three neutrino Zee model and its extension including three active and one sterile species are studied in the light of new neutrino oscillation data. We obtain analytical relations for the mixing angle in solar oscillations in terms of neutrino mass squared differences. For the four neutrino case, we obtain the result $\mathsf{sin^2 2 \theta_\odot \approx 1 - [ (\Delta m^2_{Atm})^2/(4 \Delta m^2_{LSND} \Delta m^2_\odot) ]^2}$, which can accommodate both the large and small mixing scenarios. We show that within this framework, while both the SMA-MSW and the LMA-MSW solutions can easily be accommodated, it would be difficult to reconcile the LOW-QVO solutions. We also comment on the active-sterile admixture within phenomenologically viable textures.Comment: The paper has been substantially rewritten, especially in Section IV, though the basic results are unchanged. Some new references and an appendix have been adde

Studies of Prototype CsI(Tl) Crystal Scintillators for Low-Energy Neutrino Experiments

Crystal scintillators provide potential merits for the pursuit of low-energy low-background experiments. A CsI(Tl) scintillating crystal detector is being constructed to study low-energy neutrino physics at a nuclear reactor, while projects are underway to adopt this technique for dark matter searches. The choice of the geometrical parameters of the crystal modules, as well as the optimization of the read-out scheme, are the results of an R&D program. Crystals with 40 cm in length were developed. The detector requirements and the achieved performance of the prototypes are presented. Future prospects for this technique are discussed.Comment: 32 pages, 14 figure

Measurement of the Intrinsic Radiopurity of Cs-137/U-235/U-238/Th-232 in CsI(Tl) Crystal Scintillators

The inorganic crystal scintillator CsI(Tl) has been used for low energy neutrino and Dark Matter experiments, where the intrinsic radiopurity is an issue of major importance. Low-background data were taken with a CsI(Tl) crystal array at the Kuo-Sheng Reactor Neutrino Laboratory. The pulse shape discrimination capabilities of the crystal, as well as the temporal and spatial correlations of the events, provide powerful means of measuring the intrinsic radiopurity of Cs-137 as well as the U-235, U-238 and Th-232 series. The event selection algorithms are described, with which the decay half-lives of Po-218, Po-214, Rn-220, Po-216 and Po-212 were derived. The measurements of the contamination levels, their concentration gradients with the crystal growth axis, and the uniformity among different crystal samples, are reported. The radiopurity in the U-238 and Th-232 series are comparable to those of the best reported in other crystal scintillators. Significant improvements in measurement sensitivities were achieved, similar to those from dedicated massive liquid scintillator detector. This analysis also provides in situ measurements of the detector performance parameters, such as spatial resolution, quenching factors, and data acquisition dead time.Comment: 28 pages, 12 figure

Sharp and fuzzy observables on effect algebras

Observables on effect algebras and their fuzzy versions obtained by means of confidence measures (Markov kernels) are studied. It is shown that, on effect algebras with the (E)-property, given an observable and a confidence measure, there exists a fuzzy version of the observable. Ordering of observables according to their fuzzy properties is introduced, and some minimality conditions with respect to this ordering are found. Applications of some results of classical theory of experiments are considered.Comment: 23 page