Bremsstrahlung emission during α\alpha-decay of 226Ra^{226}{\rm Ra}

We obtained the spectrum of probability of the bremsstrahlung emission accompanying the $\alpha$-decay of $^{226}{\rm Ra}$ (E$_{\alpha}$=4.8 MeV) by measuring the $\alpha$-$\gamma$ coincidences and using the model presented in our previous study on the $\alpha-$decay of $^{214}{\rm Po}$ (E$_{\alpha}$=7.7 MeV). We compare the experimental data with the quantum mechanical calculation and find a good agreement between theory and experiment. We discuss the differences between the photon spectra connected with the $\alpha$-decay of the $^{226}{\rm Ra}$ and $^{214}{\rm Po}$ nuclei. For the two mentioned nuclei we analyze the bremsstrahlung emission contributions from the tunneling and external regions of the nucleus barrier into the total spectrum, and we find the destructive interference between these contributions. We also find that the emission of photons during tunneling of the $\alpha$-particle gives an important contribution to the bremsstrahlung spectrum in the whole E$_{\gamma}$ energy range of the studied $^{226}$Ra nucleus

Multipolar model of bremsstrahlung accompanying proton-decay of nuclei

Emission of bremsstrahlung photons accompanying proton decay of nuclei is studied. The new improved multipolar model describing such a process is presented. The angular formalism of calculations of the matrix elements is stated in details. The bremsstrahlung probabilities for the $^{157}{\rm Ta}$, $^{161}{\rm Re}$, $^{167}{\rm Ir}$ and $^{185}{\rm Bi}$ nuclei decaying from the $2s_{1/2}$ state, the $^{109}_{53}{\rm I}_{56}$ and $^{112}_{55}{\rm Cs}_{57}$ nuclei decaying from the $1d_{5/2}$ state, the $^{146}_{69}{\rm Tm}_{77}$ and $^{151}_{71}{\rm Lu}_{80}$ nuclei decaying from the $0h_{11/2}$ state are predicted. Such spectra have orders of values similar to the experimental data for the bremsstrahlung photons emitted during the $\alpha$-decay. This indicates on real possibility to study bremsstrahlung photons during proton decay experimentally and perform further measurements.Comment: 14 pages, 6 figure

Standard Neutrino Spectrum from B-8 Decay

We present a systematic evaluation of the shape of the neutrino energy spectrum produced by beta-decay of $^8$B. We place special emphasis on determining the range of uncertainties permitted by existing laboratory data and theoretical ingredients (such as forbidden and radiative corrections). We review and compare the available experimental data on the $^8$B$(\beta^+){}^8$Be$(2\alpha)$ decay chain. We analyze the theoretical and experimental uncertainties quantitatively. We give a numerical representation of the best-fit (standard-model) neutrino spectrum, as well as two extreme deviations from the standard spectrum that represent the total (experimental and theoretical) effective $\pm3\sigma$ deviations. Solar neutrino experiments that are currently being developed will be able to measure the shape of the $^8$B neutrino spectrum above about 5 MeV. An observed distortion of the $^8$B solar neutrino spectrum outside the range given in the present work could be considered as evidence, at an effective significance level greater than three standard deviations, for physics beyond the standard electroweak model. We use the most recent available experimental data on the Gamow--Teller strengths in the $A=37$ system to calculate the $^8$B neutrino absorption cross section on chlorine: $\sigma_{\rm Cl}=(1.14\pm0.11)\times10^{-42}$~cm$^2$ ($\pm3\sigma$ errors). The chlorine cross section is also given as a function of the neutrino energy. The $^8$B neutrino absorption cross section in gallium is $\sigma_{\rm Ga}=(2.46^{+2.1}_{-1.1})\times10^{-42}$ cm$^2$ ($\pm3\sigma$ errors).Comment: Revised version, to appear in Phys. Rev.

Improvement of oscillometric blood pressure estimates through suppression of breathing effects

This paper addresses the suppression of the effects of the breathing signal from short duration oscillometric waveform (OMW) recordings to obtain improved blood pressure estimates. As the amplitude modulating effects due to the breathing signal are multiplicative in nature, homomorphic filtering is done on the OMW. An adaptive filtering methodology is adopted to suppress the breathing signal from the OMW. For suppressing the breathing signal, an adaptive noise canceller (ANC) scheme is used when simultaneously acquired reference electrocardiogram (ECG) signal is available while an adaptive line enhancer (ALE) scheme is used when such a reference signal is not readily available. Existing algorithms are used for estimating the blood pressure values. After the suppression of the breathing effects, an improvement in the pressure estimates is observed. Unlike the current methodologies for suppressing the breathing effects from blood pressure measurements, the ALE scheme used in this paper does not require an additional reference signal

Measurement of heart rate variability using an oscillometric blood pressure monitor

We apply the maximal overlap discrete wavelet transform (MODWT)-based spectral density estimation method to measure heart rate variability (HRV) from short-duration pulse wave signals produced by an automated oscillometric blood pressure (BP) monitor d

Extraction of breathing signal and suppression of its effects in oscillometric blood pressure measurement

Breathing causes fluctuations in blood pressure and contributes to variations in blood pressure estimates. In order to reduce the variability in the blood pressure estimates induced by breathing, either the breathing signal should be removed from the oscillometric blood pressure signal, or its effects should be suppressed. This paper presents a hybrid method that combines homomorphic and adaptive signal processing techniques to extract the breathing signal from the oscillometric signal with or without a simultaneously recorded electrocardiogram (ECG). The quality of the extracted breathing signal and the depth of breathing are assessed using the reference breathing signals. The breathing signals extracted using the accompanying ECG signal were found to be superior in quality compared to the ones extracted from the oscillometric waveform. The blood pressure estimates were evaluated before and after the breathing suppression techniques were implemented. As a result of the breathing suppression, the fluctuation of the systolic and diastolic blood pressure estimates obtained from a database of 85 healthy subjects is reduced