7,610 research outputs found
Generalized Area Spectral Efficiency: An Effective Performance Metric for Green Wireless Communications
Area spectral efficiency (ASE) was introduced as a metric to quantify the
spectral utilization efficiency of cellular systems. Unlike other performance
metrics, ASE takes into account the spatial property of cellular systems. In
this paper, we generalize the concept of ASE to study arbitrary wireless
transmissions. Specifically, we introduce the notion of affected area to
characterize the spatial property of arbitrary wireless transmissions. Based on
the definition of affected area, we define the performance metric, generalized
area spectral efficiency (GASE), to quantify the spatial spectral utilization
efficiency as well as the greenness of wireless transmissions. After
illustrating its evaluation for point-to-point transmission, we analyze the
GASE performance of several different transmission scenarios, including
dual-hop relay transmission, three-node cooperative relay transmission and
underlay cognitive radio transmission. We derive closed-form expressions for
the GASE metric of each transmission scenario under Rayleigh fading environment
whenever possible. Through mathematical analysis and numerical examples, we
show that the GASE metric provides a new perspective on the design and
optimization of wireless transmissions, especially on the transmitting power
selection. We also show that introducing relay nodes can greatly improve the
spatial utilization efficiency of wireless systems. We illustrate that the GASE
metric can help optimize the deployment of underlay cognitive radio systems.Comment: 11 pages, 8 figures, accepted by TCo
Ixazomib enhances parathyroid hormone-induced β-catenin/T-cell factor signaling by dissociating β-catenin from the parathyroid hormone receptor.
The anabolic action of PTH in bone is mostly mediated by cAMP/PKA and Wnt-independent activation of β-catenin/T-cell factor (TCF) signaling. β-Catenin switches the PTH receptor (PTHR) signaling from cAMP/PKA to PLC/PKC activation by binding to the PTHR. Ixazomib (Izb) was recently approved as the first orally administered proteasome inhibitor for the treatment of multiple myeloma; it acts in part by inhibition of pathological bone destruction. Proteasome inhibitors were reported to stabilize β-catenin by the ubiquitin-proteasome pathway. However, how Izb affects PTHR activation to regulate β-catenin/TCF signaling is poorly understood. In the present study, using CRISPR/Cas9 genome-editing technology, we show that Izb reverses β-catenin-mediated PTHR signaling switch and enhances PTH-induced cAMP generation and cAMP response element-luciferase activity in osteoblasts. Izb increases active forms of β-catenin and promotes β-catenin translocation, thereby dissociating β-catenin from the PTHR at the plasma membrane. Furthermore, Izb facilitates PTH-stimulated GSK3β phosphorylation and β-catenin phosphorylation. Thus Izb enhances PTH stimulation of β-catenin/TCF signaling via cAMP-dependent activation, and this effect is due to its separating β-catenin from the PTHR. These findings provide evidence that Izb may be used to improve the therapeutic efficacy of PTH for the treatment of osteoporosis and other resorptive bone diseases
A convex dual programming for the rational minimax approximation and Lawson's iteration
Computing the discrete rational minimax approximation in the complex plane is
challenging. Apart from Ruttan's sufficient condition, there are few other
sufficient conditions for global optimality. The state-of-the-art rational
approximation algorithms, such as the adaptive Antoulas-Anderson (AAA),
AAA-Lawson, and the rational Krylov fitting (RKFIT) method, perform highly
efficiently, but the computed rational approximants may be near-best. In this
paper, we propose a convex programming approach, the solution of which is
guaranteed to be the rational minimax approximation under Ruttan's sufficient
condition. Furthermore, we present a new version of Lawson's iteration for
solving this convex programming problem. The computed solution can be easily
verified as the rational minimax approximant. Our numerical experiments
demonstrate that this updated version of Lawson's iteration generally converges
monotonically with respect to the objective function of the convex programming.
It is an effective competitive approach for the rational minimax problem,
compared to the highly efficient AAA, AAA-Lawson, and the stabilized
Sanathanan-Koerner iteration.Comment: 38 pages, 10 figure
High-efficiency robust perovskite solar cells on ultrathin flexible substrates.
Wide applications of personal consumer electronics have triggered tremendous need for portable power sources featuring light-weight and mechanical flexibility. Perovskite solar cells offer a compelling combination of low-cost and high device performance. Here we demonstrate high-performance planar heterojunction perovskite solar cells constructed on highly flexible and ultrathin silver-mesh/conducting polymer substrates. The device performance is comparable to that of their counterparts on rigid glass/indium tin oxide substrates, reaching a power conversion efficiency of 14.0%, while the specific power (the ratio of power to device weight) reaches 1.96 kW kg(-1), given the fact that the device is constructed on a 57-μm-thick polyethylene terephthalate based substrate. The flexible device also demonstrates excellent robustness against mechanical deformation, retaining >95% of its original efficiency after 5,000 times fully bending. Our results confirmed that perovskite thin films are fully compatible with our flexible substrates, and are thus promising for future applications in flexible and bendable solar cells
muon anomaly and --philic Higgs doublet with a light CP-even component
We examine the possibilities of accommodating the muon anomaly reported
by Fermilab in the 2HDM with a discrete symmetry in which an inert Higgs
doublet field () has the lepton flavor violation -
interactions. We study the case of light (5 GeV 115 GeV) and assume
the Yukawa matrices to be real and symmetrical. Considering relevant
theoretical and experimental constraints, especially for the multi-lepton
searches at the LHC, we find the muon anomaly can be explained within
range in the region of 5 GeV GeV, 130 GeV 610 GeV, and 0.005 0.014. Meanwhile, the
fitting the data of lepton flavour universality in the
decays approaches to the SM prediction.Comment: 12 pages, 4 figures. arXiv admin note: text overlap with
arXiv:2104.03227. text overlap with arXiv:1908.0375
Assessment of Snow Status Changes Using L-HH Temporal-Coherence Components at Mt. Dagu, China
Multitemporal Phased Array type L-band Synthetic Aperture Radar (PALSAR)
horizontally transmitted and horizontally received (HH) coherence data was decomposed
into temporal-coherence, spatial-coherence, and thermal noise components. The
multitemporal data spanned between February and May of 2008, and consisted of two pairs
of interferometric SAR (InSAR) images formed by consecutive repeat passes. With the
analysis of ancillary data, a snow increase process and a snow decrease process were
determined. Then, the multiple temporal-coherence components were used to study the
variation of thawing and freezing statuses of snow because the components can mostly
reflect the temporal change of the snow that occurred between two data acquisitions.
Compared with snow mapping results derived from optical images, the outcomes from the
snow increase process and the snow decrease process reached an overall accuracy of 71.3%
and 79.5%, respectively. Being capable of delineating not only the areas with or without snow cover but also status changes among no-snow, wet snow, and dry snow, we have
developed a critical means to assess the water resource in alpine areas
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