Learning-Based Distributed Detection-Estimation in Sensor Networks with Unknown Sensor Defects

We consider the problem of distributed estimation of an unknown deterministic scalar parameter (the target signal) in a wireless sensor network (WSN), where each sensor receives a single snapshot of the field. We assume that the observation at each node randomly falls into one of two modes: a valid or an invalid observation mode. Specifically, mode one corresponds to the desired signal plus noise observation mode (\emph{valid}), and mode two corresponds to the pure noise mode (\emph{invalid}) due to node defect or damage. With no prior information on such local sensing modes, we introduce a learning-based distributed procedure, called the mixed detection-estimation (MDE) algorithm, based on iterative closed-loop interactions between mode learning (detection) and target estimation. The online learning step re-assesses the validity of the local observations at each iteration, thus refining the ongoing estimation update process. The convergence of the MDE algorithm is established analytically. Asymptotic analysis shows that, in the high signal-to-noise ratio (SNR) regime, the MDE estimation error converges to that of an ideal (centralized) estimator with perfect information about the node sensing modes. This is in contrast to the estimation performance of a naive average consensus based distributed estimator (without mode learning), whose estimation error blows up with an increasing SNR.Comment: 15 pages, 2 figures, submitted to TS

Potential novel bZIP-like gene for resistance to Erysiphe necator identified in Chinese wild Vitis pseudoreticulata

In this study, a novel bZIP-like gene was isolated from Chinese wild Vitis pseudoreticulata W. T. acc. Baihe-35-1. The full-length complementary deoxyribonucleic acid (cDNA) sequence of the gene was 1583 bp including 159 bp 5’ untranslated region (UTR), 365 bp 3’ UTR and a 1083 bp ORF which encodes a polypeptide of 360 amino acids with a molecular weight of 38.662 kDa. The deduced amino acid sequence shares an overall 46 to 69.8% sequence similarity with bZIP from other plants. Therefore, we designated this gene as V. pseudoreticulata bZIP (VpbZIP-like). The expression of VpbZIP-like was induced 12 h post inoculation (hpi) by Erysiphe necator, but transiently decreased, then increased in these two genotypes and its expression was lower in highly resistant genotype Baihe-35-1 than in susceptible genotype Hunan-1 at 24, 48 and 72 hpi. We further tested whether the expression was also a response to plant signaling molecules. Results indicate that the susceptible genotype Hunan-1 showed higher expression of VpbZIP-like than the highly resistant genotype Baihe-35-1 after exogenous application of methyl jasmonate (MeJA), salicylic acid (SA) and ethephon (Eth). Moreover, tissue specific expression pattern of VpbZIP-like was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Results reveal that it was in lower lever in flower than in leaf, stem, tendril and fruit. The CDS of VpbZIP-like was inserted into the prokaryotic expression construct pGEX-4T-1, and then transformed into Escherichia coli BL21-code induced by isopropyl-b-D-thiogalactopyranoside (IPTG) which resulted in the production of a Mr. 64 kDa of GST- VpbZIP-like fusion protein displayed in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).Key words: Chinese wild Vitis, bZIP, gene expression, signaling molecules, fusion protein expression

Active cancellation of servo-induced noise on stabilized lasers via feedforward

Many precision laser applications require active frequency stabilization. However, such stabilization loops operate by pushing noise to frequencies outside their bandwidth, leading to large "servo bumps" that can have deleterious effects for certain applications. The prevailing approach to filtering this noise is to pass the laser through a high finesse optical cavity, which places constraints on the system design. Here, we propose and demonstrate a different approach where a frequency error signal is derived from a beat note between the laser and the light that passes through the reference cavity. The phase noise derived from this beat note is fed forward to an electro-optic modulator after the laser, carefully accounting for relative delay, for real-time frequency correction. With a Hz-linewidth laser, we show $\gtrsim20$ dB noise suppression at the peak of the servo bump ($\approx250$ kHz), and a noise suppression bandwidth of $\approx5$ MHz -- well beyond the servo bump. By simulating the Rabi dynamics of a two-level atom with our measured data, we demonstrate substantial improvements to the pulse fidelity over a wide range of Rabi frequencies. Our approach offers a simple and versatile method for obtaining a clean spectrum of a narrow linewidth laser, as required in many emerging applications of cold atoms, and is readily compatible with commercial systems that may even include wavelength conversion

Repetitive readout and real-time control of nuclear spin qubits in 171^{171}Yb atoms

We demonstrate high fidelity repetitive projective measurements of nuclear spin qubits in an array of neutral ytterbium-171 ($^{171}$Yb) atoms. We show that the qubit state can be measured with a fidelity of 0.995(4) under a condition that leaves it in the state corresponding to the measurement outcome with a probability of 0.993(6) for a single tweezer and 0.981(4) averaged over the array. This is accomplished by near-perfect cyclicity of one of the nuclear spin qubit states with an optically excited state under a magnetic field of $B=58$ G, resulting in a bright/dark contrast of $\approx10^5$ during fluorescence readout. The performance improves further as $\sim1/B^2$. The state-averaged readout survival of 0.98(1) is limited by off-resonant scattering to dark states and can be addressed via post-selection by measuring the atom number at the end of the circuit, or during the circuit by performing a measurement of both qubit states. We combine projective measurements with high-fidelity rotations of the nuclear spin qubit via an AC magnetic field to explore several paradigmatic scenarios, including the non-commutivity of measurements in orthogonal bases, and the quantum Zeno mechanism in which measurements "freeze" coherent evolution. Finally, we employ real-time feedforward to repetitively deterministically prepare the qubit in the $+z$ or $-z$ direction after initializing it in an orthogonal basis and performing a projective measurement in the $z$-basis. These capabilities constitute an important step towards adaptive quantum circuits with atom arrays, such as in measurement-based quantum computation, fast many-body state preparation, holographic dynamics simulations, and quantum error correction

Evaluation of ultrasonography in fetal intestinal malrotation with midgut volvulus

Objectives: To investigate the clinical significance of prenatal diagnosis and prognostic evaluation of fetal intestinal malrotation with midgut volvulus via ultrasonography. Material and methods: Ultrasonographic findings and clinical outcomes of fetal intestinal malrotation with midgut volvulus prenatally diagnosed via ultrasound at the Zhangzhou Hospital Affiliated of Fujian Medical University from January 2013 to May 2020 were summarised and analyzed. Results: Eleven cases of fetal intestinal malrotation with midgut volvulus were accurately prenatally diagnosed according to the specific ultrasound signs, such as ‘whirlpool sign’ and ‘twining sign’. Indirect and nonspecific ultrasonographic signs included ascites in four cases and echogenic bowel in nine, all of which were accompanied by intestinal dilatation at various degrees. Among all cases, two were complicated with other system abnormalities, and one had a chromosome abnormality. Three pregnant women chose termination of pregnancy, and eight neonates were transferred to the pediatric department for surgery after obtaining written informed consent. An accurate prenatal diagnosis was confirmed postoperatively, and the fetus recovered well postoperatively. Conclusions: Fetal intestinal malrotation with midgut volvulus has typical sonographic features, and ultrasonography is the method of choice for prenatal diagnosis of this disease. Fetal intestinal malrotation with midgut volvulus is a non-fatal congenital malformation that can be treated. Prenatal diagnosis is essential for early postnatal treatment, and early surgery can often obtain good efficacy and prognosis

Candida dubliniensis fungemia: the first four cases in North America.

We report the first four North American cases of Candida dubliniensis fungemia, including the first isolation of this organism from the bloodstream of an HIV-infected person. All isolates were susceptible in vitro to commonly used antifungal drugs. This report demonstrates that C. dubliniensis can cause bloodstream infection; however, the incidence of disease is not known

Estimation of cell concentration using high-frequency ultrasonic backscattering

Abstract Cell concentration is a crucial quantity for both clinical diagnostic examinations and cell culture studies. However, typical modalities for cell concentration measurements are either time-consuming or not cost-effective. In the present study, cell concentration is estimated using high-frequency ultrasonic backscattering. Validation tests indicate that the proposed method can differentiate red blood cells (RBCs) of various hematocrits. A 50-MHz ultrasound system with appropriate sensitivity is utilized to estimate cell concentrations from a small volume of RBCs suspended in saline, with hematocrits ranging from 1.66 × 10 -4 to 10%, and fibroblasts, with concentrations ranging from 2 × 10 4 to 128 × 10 4 cells/mL. The backscatter strength and statistical distribution, characterized by the Nakagami parameter, are calculated from gated signals for quantitatively assessing the samples. Results show that the backscatter strength of RBCs linearly increases with increasing hematocrit level in the hematocrit range of 3 to 10%, which agrees well with results of previous studies. The backscatter strength of RBCS has an exponential relationship with the hematocrit level in the hematocrit range of 1.66 × 10 -4 to 3%. The corresponding Nakagami parameter is sensitive to electronic noise as long as the signal-to-noise ratio decreasing follows with the decrease of RBC hematocrits at the concentration lower than 0.85%. The backscatter strength of fibroblasts exponentially increases with increasing fibroblasts concentration, which is consistent with results obtained from typical optical density measurements. A linear relationship, with correlation coefficient of 0.99, between the results of ultrasonic backscattering and those of the optical density measurements is established. High-frequency ultrasonic backscattering can be applied to sensitively estimate the concentrations of small volumes of cells

Systematic study of TiO2/ZnO mixed metal oxides for CO2 photoreduction

A two component three degree simplex lattice experimental design was employed to evaluate the impact of different mixing ratios of TiO2 and ZnO on an ordered mesoporous SBA-15 support for CO2 photoreduction. It was anticipated that their combined advantages: low cost, non-toxicity and combined electronic properties would facilitate CO2 photoreduction. The ratio of TiO2 used had a statistically significant positive impact on CO (b1 = 9.71, p-value = 2.9310–4) and CH4 (b1 = 1.43, p-value = 1.3510–3) cumulative production. A negative impact, from the interaction term between the ratios of TiO2 and ZnO, was found for CH4 cumulative production (b3 = -2.64, p-value = 2.3010–2). The systematic study provided evidence for the possible loss in CO2 photoreduction activity from sulphate groups. The decrease in activity is attributed to the presence of sulphate species in the ZnO prepared, which may possibly act as charge carrier and/or radical intermediate scavengers

Chemical features of Ganoderma polysaccharides with antioxidant, antitumor and antimicrobial activities

Review aricleGanoderma genus comprises one of the most commonly studied species worldwide, G. lucidum. However, other Ganoderma species have been also reported as important sources of bioactive compounds. Polysaccharides are important contributors to the medicinal properties reported for Ganoderma species, as demonstrated by the numerous publications, including reviews, on this matter. Yet, what are the chemical features of Ganoderma polysaccharides that have bioactivity? In the present manuscript, the chemical features of Ganoderma polysaccharides with reported antioxidant, antitumor and antimicrobial activities (the most studied worldwide) are analyzed in detail. The composition of sugars (homo- versus hetero-glucans and other polysaccharides), type of glycosidic linkages, branching patterns, and linkage to proteins are discussed. Methods for extraction, isolation and identification are evaluated and, finally, the bioactivity of polysaccharidic extracts and purified compounds are discussed. The integration of data allows deduction of structure-activity relationships and gives clues to the chemical aspects involved in Ganoderma bioactivity