Threshold Effects in the Decay of Heavy b' and t' Quarks

A sequential fourth generation is still viable, but the t' and b' quarks are constrained to be not too far apart in mass. The t'{\to}bW and b'{\to}tW decay channels are still being pursued at the Tevatron, which would soon be surpassed by the LHC. We use a convolution method with up to five-body final state to study t' and b' decays. We show how the two decay branches for m_{b'} below the tW threshold, b'{\to}tW^* and t^*W, merge with b'{\to}tW above the threshold. We then consider the heavy-to-heavy transitions b'{\to}t^{\prime(*)}W^{(*)} (or t'{\to}b^{\prime(*)}W^{(*)}), as they are not suppressed by quark mixing. We find that, because of the threshold sensitivity of the branching fraction of t'{\to}b'W^* (or b'{\to}t'W^*), it is possible to measure the strength of the CKM mixing element V_{t'b} (or V_{tb'}), especially when it is rather small. We urge the experiments to pursue and separate the t'{\to}b'W^* (or b'{\to}t'W^*) decay in their search program

T Oligo-Primed Polymerase Chain Reaction (TOP-PCR): A Robust Method for the Amplification of Minute DNA Fragments in Body Fluids.

Body fluid DNA sequencing is a powerful noninvasive approach for the diagnosis of genetic defects, infectious agents and diseases. The success relies on the quantity and quality of the DNA samples. However, numerous clinical samples are either at low quantity or of poor quality due to various reasons. To overcome these problems, we have developed T oligo-primed polymerase chain reaction (TOP-PCR) for full-length nonselective amplification of minute quantity of DNA fragments. TOP-PCR adopts homogeneous "half adaptor" (HA), generated by annealing P oligo (carrying a phosphate group at the 5' end) and T oligo (carrying a T-tail at the 3' end), for efficient ligation to target DNA and subsequent PCR amplification primed by the T oligo alone. Using DNA samples from body fluids, we demonstrate that TOP-PCR recovers minute DNA fragments and maintains the DNA size profile, while enhancing the major molecular populations. Our results also showed that TOP-PCR is a superior method for detecting apoptosis and outperforms the method adopted by Illumina for DNA amplification

Preparation and Characterization of Hyperbranched Oligomer Modified LiMn2O4 thin Film Cathodes

AbstractThe LiMn2O4 thin film electrode modified by hyperbranched oligomer has been prepared and studied. The hyperbranched oligomer can be self-polymerized for reducing the thermal-runaway hazard by the internal short protection mechanism in lithium ion batteries. The influence of the oligomer coating on cathode has been studied with the binder/carbon-free thin film. In the various C-rate charged-discharged tests, there are no significant differences between the cells with/without the oligomer coating. In this research, the hyperbranched oligomer additive acts as a protection to improve the thermal stability of LiMn2O4. Therefore, the property of thermal stability and its function in safety may benefit the future development of electric vehicles

Noninvasive prediction of Blood Lactate through a machine learning-based approach.

We hypothesized that blood lactate concentration([Lac]blood) is a function of cardiopulmonary variables, exercise intensity and some anthropometric elements during aerobic exercise. This investigation aimed to establish a mathematical model to estimate [Lac]blood noninvasively during constant work rate (CWR) exercise of various intensities. 31 healthy participants were recruited and each underwent 4 cardiopulmonary exercise tests: one incremental and three CWR tests (low: 35% of peak work rate for 15 min, moderate: 60% 10 min and high: 90% 4 min). At the end of each CWR test, venous blood was sampled to determine [Lac]blood. 31 trios of CWR tests were employed to construct the mathematical model, which utilized exponential regression combined with Taylor expansion. Good fitting was achieved when the conditions of low and moderate intensity were put in one model; high-intensity in another. Standard deviation of fitting error in the former condition is 0.52; in the latter is 1.82 mmol/liter. Weighting analysis demonstrated that, besides heart rate, respiratory variables are required in the estimation of [Lac]blood in the model of low/moderate intensity. In conclusion, by measuring noninvasive cardio-respiratory parameters, [Lac]blood during CWR exercise can be determined with good accuracy. This should have application in endurance training and future exercise industry

Nuclear Shell Model Calculations with Fundamental Nucleon-Nucleon Interactions

Some fundamental Nucleon-Nucleon interactions and their applications to finite nuclei are reviewed. Results for the few-body systems and from Shell-Model calculations are discussed and compared to point out the advantages and disadvantages of the different Nucleon-Nucleon interactions. The recently developed Drexel University Shell Model (DUSM) code is mentioned.Comment: 16 pages, 4 figures. To appear in Phys. Rep. 199

Predicting the network of substrate-enzyme-product triads by combining compound similarity and functional domain composition

<p>Abstract</p> <p>Background</p> <p>Metabolic pathway is a highly regulated network consisting of many metabolic reactions involving substrates, enzymes, and products, where substrates can be transformed into products with particular catalytic enzymes. Since experimental determination of the network of substrate-enzyme-product triad (whether the substrate can be transformed into the product with a given enzyme) is both time-consuming and expensive, it would be very useful to develop a computational approach for predicting the network of substrate-enzyme-product triads.</p> <p>Results</p> <p>A mathematical model for predicting the network of substrate-enzyme-product triads was developed. Meanwhile, a benchmark dataset was constructed that contains 744,192 substrate-enzyme-product triads, of which 14,592 are networking triads, and 729,600 are non-networking triads; i.e., the number of the negative triads was about 50 times the number of the positive triads. The molecular graph was introduced to calculate the similarity between the substrate compounds and between the product compounds, while the functional domain composition was introduced to calculate the similarity between enzyme molecules. The nearest neighbour algorithm was utilized as a prediction engine, in which a novel metric was introduced to measure the "nearness" between triads. To train and test the prediction engine, one tenth of the positive triads and one tenth of the negative triads were randomly picked from the benchmark dataset as the testing samples, while the remaining were used to train the prediction model. It was observed that the overall success rate in predicting the network for the testing samples was 98.71%, with 95.41% success rate for the 1,460 testing networking triads and 98.77% for the 72,960 testing non-networking triads.</p> <p>Conclusions</p> <p>It is quite promising and encouraged to use the molecular graph to calculate the similarity between compounds and use the functional domain composition to calculate the similarity between enzymes for studying the substrate-enzyme-product network system. The software is available upon request.</p

How do China’s lockdown and post-COVID-19 stimuli impact carbon emissions and economic output? Retrospective estimates and prospective trajectories

This paper develops a multi-sector and multi-factor structural gravity model that allows an analytical and quantitative decomposition of the emission and output changes into composition and technique effects. We find that the negative production shock of China's containment policy propagates globally via supply chains, with the carbon-intensive sectors experiencing the greatest carbon emission shocks. We further reveal that China's current stimulus package in 2021-2025 is consistent with China's emission intensity-reduction goals for 2025, but further efforts are required to meet China's carbon emissions-peaking target in 2030 and Cancun 2°C goal. Short-term changes in carbon emissions resulting from lockdowns and initial fiscal stimuli in "economic rescue" period have minor long-term effects, whereas the transitional direction of future fiscal stimulus exerts more predominant impact on long-term carbon emissions. The efficiency improvement effects are more important than the sectoral structure effects of the fiscal stimulus in achieving greener economic growth. [Abstract copyright: © 2022 The Author(s).

Nonhomogeneous seawater Sr isotopic composition in the coastal oceans : a novel tool for tracing water masses and submarine groundwater discharge

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 12 (2011): Q05002, doi:10.1029/2010GC003372.Here we present high-precision (2σ = ±3 ppm) 87Sr/86Sr measurements in coastal waters, together with salinity, to evaluate water mass mixing and the influence of submarine groundwater discharge (SGD) in coastal waters and marginal seas. Nonhomogeneous Sr isotopic variations in water columns were documented in the Southern Okinawa Trough (SOT), South China Sea, and Kao-ping Canyon (KPC), where seawater 87Sr/86Sr varied up to 70 ppm. Seawater Sr isotopic composition changes only slightly in the upper 200 m of the SOT but was detectable and highly correlated with salinity, indicating a mixing between radiogenic North Pacific Tropical Water (high 87Sr/86Sr and high salinity) at 100–150 m and a less radiogenic component with low 87Sr/86Sr and low salinity at ∼200 m. Vertical profiles of seawater 87Sr/86Sr along the KPC show significant variations, suggesting dynamic mixing affected by continental inputs (i.e., river runoff and SGD) in this region. These results highlight the potential use of seawater Sr isotopes as a powerful tracer for determining mixing ratios and the dynamic mixing of oceanic water masses, especially in coastal and marginal seas.This research was supported by a postdoctoral fellowship from Top University (NCKU), Taiwan, to K.‐F. Huang and funds from NSC and MOE, Taiwan, to C.‐F. You