The BetaCage, an ultra-sensitive screener for surface contamination

Material screening for identifying low-energy electron emitters and alpha-decaying isotopes is now a prerequisite for rare-event searches (e.g., dark-matter direct detection and neutrinoless double-beta decay) for which surface radiocontamination has become an increasingly important background. The BetaCage, a gaseous neon time-projection chamber, is a proposed ultra-sensitive (and nondestructive) screener for alpha- and beta-emitting surface contaminants to which existing screening facilities are insufficiently sensitive. Sensitivity goals are 0.1 betas per keV-m$^2$-day and 0.1 alphas per m$^2$-day, with the former limited by Compton scattering of photons in the screening samples and (thanks to tracking) the latter expected to be signal-limited; radioassays and simulations indicate backgrounds from detector materials and radon daughters should be subdominant. We report on details of the background simulations and detector design that provide the discrimination, shielding, and radiopurity necessary to reach our sensitivity goals for a chamber with a 95$\times$95 cm$^2$ sample area positioned below a 40 cm drift region and monitored by crisscrossed anode and cathode planes consisting of 151 wires each.Comment: 5 pages, 3 figures, Proceedings of Low Radioactivity Techniques (LRT) 2013, Gran Sasso, Italy, April 10-12, 201

Estimating Seasonal Moving Average Model Using Bayesian Approach

This paper utilizes the Gibbs sampling technique to develop a Bayesian inference for Seasonal Moving Average (SMA) model, which includes parameters that distinguish between Multiplicative and Non-multiplicative models (referred to as Augmented Seasonal Moving Average hereafter). The construction of Bayesian inference involves several steps. Firstly, the method of Non-linear least squares (NLS) is used to estimate unknown lagged errors, allowing for the approximation of the complex likelihood function. Secondly, both a semi-conjugate prior distribution and a non- informative prior distribution are applied to the unknown parameters and initial errors. Thirdly, the prior distributions are combined with the approximated likelihood function to obtain the joint posterior distribution. Lastly, the full conditional distributions are derived as part of the Gibbs sampling process. The proposed method is notable for its simplicity in assessing the significance of the parameters that distinguish between Multiplicative and Non-multiplicative models, a task that is challenging to accomplish using classical analysis. The convergence of the method was verified, ensuring that it reached stable and reliable results

Possible presence of calcium channel blocker(s) in Rubia cordifolia: An indigenous medicinal plant

Crude extract of Rubia cordifolia (RC) was tested in isolated tissue preparations for its possible calcium channel antagonistic activity. RC suppressed the spontaneous contractions of guinea-pig atria, rabbit jejunum and rat uterus in a concentration dependent manner (0.1-3 mg/ml). In rabbit aorta, it inhibited norepinephrine (10 microM) and KCl (80 mM) induced contractions. Replacement of physiological salt solution with calcium free solution abolished the spontaneous movements of rabbit jejunum. However, addition of calcium (25 micrograms/ml) in the tissue bath restored the spontaneous movements. When the tissues were pretreated with plant extract (1 mg/ml) or verapamil (0.5 microgram/ml), addition of calcium failed to restore spontaneous contractions. These results indicate that the plant extract exhibits spasmolytic activity similar to that of verapamil suggestive of presence of calcium channel blocker like constituent(s) in this plant

Biofilm-based simultaneous nitrification, denitrification, and phosphorous uptake in wastewater by Neurospora discreta

Biological removal of nitrogen and phosphorous from wastewater conventionally involves multiple processing steps to satisfy the differing oxygen requirements of the microbial species involved. In this work, simultaneous nitrification, denitrification, and phosphorous removal from synthetic wastewater were achieved by the fungus Neurospora discreta in a single-step, biofilm-based, aerobic process. The concentrations of carbon, nitrogen, and phosphorous in the synthetic wastewater were systematically varied to investigate their effects on nutrient removal rates and biofilm properties. Biofilm growth was significantly (p < 0.05) affected by carbon and nitrogen, but not by phosphorous concentration. Scanning electron microscopy revealed the effects of nutrients on biofilm microstructure, which in turn correlated with nutrient removal efficiencies. The carbohydrate and protein content in the biofilm matrix decreased with increasing carbon and nitrogen concentrations but increased with increasing phosphorous concentration in the wastewater. High removal efficiencies of carbon (96%), ammonium (86%), nitrate (100%), and phosphorus (82%) were achieved under varying nutrient conditions. Interestingly, decreasing the phosphorus concentration increased the nitrification and denitrification rates, and decreasing the nitrogen concentration increased the phosphorus removal rates significantly (p < 0.05). Correlations between biofilm properties and nutrient removal rates were also evaluated in this study

Hard diffraction in hadron--hadron interactions and in photoproduction

Hard single diffractive processes are studied within the framework of the triple--Pomeron approximation. Using a Pomeron structure function motivated by Regge--theory we obtain parton distribution functions which do not obey momentum sum rule. Based on Regge-- factorization cross sections for hard diffraction are calculated. Furthermore, the model is applied to hard diffractive particle production in photoproduction and in $p\bar{p}$ interactions.Comment: 13 pages, Latex, 13 uuencoded figure

MUMAP: Modified Ultralightweight Mutual Authentication protocol for RFID enabled IoT networks

Flawed authentication protocols led to the need for a secured protocol for radio frequency identification (RFID) techniques. In this paper, an authentication protocol named Modified ultralightweight mutual authentication protocol (MUMAP) has been proposed and cryptanalysed by Juel-Weis challenge. The proposed protocol aimed to reduce memory requirements in the authentication process for low-cost RFID tags with limited resources. Lightweight operations like XOR and Left Rotation, are used to circumvent the flaws made in the other protocols. The proposed protocol has three-phase of authentication. Security analysis of the proposed protocol proves its resistivity against attacks like desynchronization, disclosure, tracking, and replay attack. On the other hand, performance analysis indicates that it is an effective protocol to use in low-cost RFID tags. Juel-Weis challenge verifies the proposed protocol where it shows insusceptibility against modular operations

Electronic and optical properties of Bi2Se3 topological insulator: a promising absorbing layer for broadband photodetector

Bismuth selenide (Bi2Se3) is a van der Waals compound which has been excellently reported as thermoelectric material. Linear dispersion near Fermi energy level is an exciting feature to consider, a promising candidate for photonic device within broadband wavelengths. For this application, detailed knowledge of its structural, electronic and optical properties is very essential. The electronic properties were determined by density functional theory (DFT) calculations implemented in Quantum-Espresso simulation package which uses plane wave basis and pseudopotential for the core electrons. Optical properties are computed by solving Bethe-Salpeter equation of many-body perturbation theory (MBPT) as implemented in Yambo code. The band structure results show the semiconducting behaviour of Bi2Se3. Taken into account the effects of electron-hole interaction by solving Bethe-Salpeter equation, the calculated optical properties are in better agreement with available experimental results. The exciton energy shows that the title material can absorb light within infrared region

Coulomb blockade in silicon based structures at temperatures up to 50 K

Coulomb blockade has been observed in the current-voltage characteristics of structures fabricated in silicon germanium delta-doped material at temperatures up to 50 K. This is consistent with the estimated effective tunnel capacitance of 10 aF which is significantly smaller than the reported capacitances of tunnel junctions made from Al or GaAs/AlGaAs heterostructures