6,055 research outputs found
Top quark forward-backward asymmetry and charge asymmetry in left-right twin Higgs model
In order to explain the Tevatron anomaly of the top quark forward-backward
asymmetry in the left-right twin Higgs model, we choose to give up
the lightest neutral particle of field as a stable dark matter
candidate. Then a new Yukawa interaction for is allowed, which can be
free from the constraint of same-sign top pair production and contribute
sizably to . Considering the constraints from the production rates of
the top pair (), the top decay rates and invariant mass
distribution, we find that this model with such new Yukawa interaction can
explain measured at the Tevatron while satisfying the charge
asymmetry measured at the LHC.Moreover, this model predicts a
strongly correlation between at the LHC and at the
Tevatron, i.e., increases as increases.Comment: 17 pages, 9 figures; matches the published versio
A survey of Chinese herbal ingredients with liver protection activities
A literature survey was conducted on herbs, their preparations and ingredients with reported liver protection activities, in which a total of 274 different species and hundreds of active ingredients have been examined. These ingredients can be roughly classified into two categories according to their activities: (1) the main ingredients, such as silybin, osthole, coumarin, glycyrrhizin, saikosaponin A, schisandrin A, flavonoids; and (2) supporting substances, such as sugars, amino acids, resins, tannins and volatile oil. Among them, some active ingredients have hepatoprotective activities (e.g. anti-inflammatory, anticancer, antioxidant, immunomodulating and liver cirrhosis-regulating effects). Calculation of physicochemical parameters indicates that the main ingredients with negative and positive Elumo values possibly display their hepatoprotective effects through different mechanisms, such as antioxidative, anti-inflammatory and immunomodulating effects. As the combination of herbs may achieve some treatment effects synergistically and/or additively, it is common in Chinese medicine to use mixtures of various medicinal herbs with pharmacologically active compounds to have synergistic and/or additive effects, or to reduce harmful effects of some pharmacologically active compounds. In particular, the active compounds with Clog P around 2 are suitable for passive transport across membranes and accessible to the target sites. Thus, Elumo and Clog P values are good indicators among the calculated parameters
Testing new physics models by top charge asymmetry and polarization at the LHC
As a top quark factory, the LHC can test the new physics models used to
explain the top quark forward-backward asymmetry A^t_FB measured at the
Tevatron. In this work we perform a comparative study for two such models: the
W'-model and the color triplet diquark (\phi) model. Requiring these models to
explain A^t_FB and also satisfy the top pair production rate measured at the
Tevatron, we examine their contributions to the LHC observables such as the
polarization and charge asymmetry in top quark and W' (or \phi) productions. We
find that these observables can be enhanced to the observable level and the
current LHC measurement on the top charge asymmetry can already tightly
constrain the W'-model. We also find that each observable shows different
characteristics in different models, which can be utilized to discriminate the
models.Comment: discussions added, version accepted by Phys. Rev.
High-Performance Screen-Printed Thermoelectric Films on Fabrics.
Printing techniques could offer a scalable approach to fabricate thermoelectric (TE) devices on flexible substrates for power generation used in wearable devices and personalized thermo-regulation. However, typical printing processes need a large concentration of binder additives, which often render a detrimental effect on electrical transport of the printed TE layers. Here, we report scalable screen-printing of TE layers on flexible fiber glass fabrics, by rationally optimizing the printing inks consisting of TE particles (p-type Bi0.5Sb1.5Te3 or n-type Bi2Te2.7Se0.3), binders, and organic solvents. We identified a suitable binder additive, methyl cellulose, which offers suitable viscosity for printability at a very small concentration (0.45-0.60 wt.%), thus minimizing its negative impact on electrical transport. Following printing, the binders were subsequently burnt off via sintering and hot pressing. We found that the nanoscale defects left behind after the binder burnt off became effective phonon scattering centers, leading to low lattice thermal conductivity in the printed n-type material. With the high electrical conductivity and low thermal conductivity, the screen-printed TE layers showed high room-temperature ZT values of 0.65 and 0.81 for p-type and n-type, respectively
NMDA Receptors Subserve Persistent Neuronal Firing during Working Memory in Dorsolateral Prefrontal Cortex
SummaryNeurons in the primate dorsolateral prefrontal cortex (dlPFC) generate persistent firing in the absence of sensory stimulation, the foundation of mental representation. Persistent firing arises from recurrent excitation within a network of pyramidal Delay cells. Here, we examined glutamate receptor influences underlying persistent firing in primate dlPFC during a spatial working memory task. Computational models predicted dependence on NMDA receptor (NMDAR) NR2B stimulation, and Delay cell persistent firing was abolished by local NR2B NMDAR blockade or by systemic ketamine administration. AMPA receptors (AMPARs) contributed background depolarization to sustain network firing. In contrast, many Response cells were sensitive to AMPAR blockade and increased firing after systemic ketamine, indicating that models of ketamine actions should be refined to reflect neuronal heterogeneity. The reliance of Delay cells on NMDAR may explain why insults to NMDARs in schizophrenia or Alzheimer’s disease profoundly impair cognition
The East-Asian VLBI Network
The East-Asian VLBI Network (EAVN) is the international VLBI facility in East
Asia and is conducted in collaboration with China, Japan, and Korea. The EAVN
consists of VLBI arrays operated in each East Asian country, containing 21
radio telescopes and three correlators. The EAVN will be mainly operated at 6.7
(C-band), 8 (X-band), 22 (K-band), and 43 GHz (Q-band), although the EAVN has
an ability to conduct observations at 1.6 - 129 GHz. We have conducted fringe
test observations eight times to date at 8 and 22 GHz and fringes have been
successfully detected at both frequencies. We have also conducted science
commissioning observations of 6.7 GHz methanol masers in massive star-forming
regions. The EAVN will be operational from the second half of 2017, providing
complementary results with the FAST on AGNs, massive star-forming regions, and
evolved stars with high angular resolution at cm- to mm-wavelengths.Comment: 6 pages, 3 figures, 2 tables. To appear in the proceedings of
"Frontiers in Radio Astronomy and FAST Early Sciences Symposium 2015" ed. Lei
Qian (ASP Conf. Ser.
Opening Fukushima floodgates: Modelling 137Cs impact in marine biota.
Nº ArtÃculo 112645A numerical model was applied to simulate the transport of 137Cs released with the waters which were used to
cool Fukushima reactors. These stored waters will be released to the Pacific Ocean according to Japanese gov ernment plans. The radionuclide transport model is Lagrangian and includes radionuclide interactions with
sediments and an integrated dynamic foodweb model for biota uptake. Calculations made from a conservative
approach indicate that expected concentrations in sediments and marine fish would be orders of magnitude
below those detected after Fukushima accident and also lower than those resulting from global fallout
background
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