Bayesian learning aided massive antenna array based THz MIMO systems are designed for spatial-wideband and frequency-wideband scenarios, collectively termed as the dual-wideband channels. ...Essentially, numerous antenna modules of the THz system result in a significant delay in the transmission/ reception of signals in the time-domain across the antennas, which leads to spatial-selectivity. As a further phenomenon, the wide bandwidth of THz communication results in substantial variation of the effective angle of arrival/ departure (AoA/ AoD) with respect to the subcarrier frequency. This is termed as the beam squint effect, which renders the channel state information (CSI) estimation challenging in such systems. To address this problem, initially, a pilot-aided (PA) Bayesian learning (PA-BL) framework is derived for the estimation of the Terahertz (THz) MIMO channel that relies exclusively on the pilot beams transmitted. Since the framework designed can successfully operate in an ill-posed model, it can verifiably lead to reduced pilot transmissions in comparison to conventional methodologies. The above paradigm is subsequently extended to additionally incorporate data symbols to derive a Data-Aided (DA) BL approach that performs joint data detection and CSI estimation. We will demonstrate that it is capable of improving the dual-wideband channel's estimate, despite further reducing the training overhead. The Bayesian Cramér-Rao bounds (BCRLBs) are also obtained for explicitly characterizing the lower bounds on the mean squared error (MSE) of the PA-BL and DA-BL frameworks. Our simulation results show the improved normalized MSE (NMSE) and bit-error rate (BER) performance of the proposed estimation schemes and confirm that they approach their respective BCRLB benchmarks.
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•Various morphologies of CuO nanostructures are formed in the presence of organic acids.•Rod-, sphere-, star-, and flower-shaped morphologies of CuO are obtained.•The morphology ...variations of CuO nanomaterials have been explained.•The catalytic ability of CuO samples toward 4-NP reduction has been compared.•Star-shaped CuO has shown superior catalytic activity toward 4-NP reduction.
Ligand-regulated growth of various morphologies of copper oxide (CuO) nanostructures has been achieved through an aqueous-based chemical precipitation route where the Cu2+ ions were stabilized through complexation with different organic acids (viz. acetic/citric/tartaric acid). The rod-, spherical-, star-, and flower-shaped morphologies of the CuO nanostructures, obtained in the presence of the different carboxylic acids, have been characterized using XRD, FTIR, HRTEM, DLS, and zeta potential measurements, while their specific surface areas and the associated band gap energies have been compared. The catalytic performance of the different CuO nanostructures has been affirmed by monitoring the reduction of 4-nitrophenol by NaBH4 in real time using UV–visible absorption spectroscopy. The star-shaped morphologies of CuO have been found to show maximum catalytic activity toward the reduction of 4-nitrophenol in the presence of NaBH4, which can be correlated to their higher specific surface area and positive surface charge and to the presence of a high indexed facet.
Forest inventories are critical for effective management of forest resources. Recently, the use of terrestrial laser scanning (TLS) to automatically extract forest inventory parameters at tree level ...(e.g. tree location, diameter at breast height (DBH) and height) has gained significant importance. TLS using both single-scan and multi-scan techniques, not only helps in detailed and accurate measurements of tree objects but also helps increase the measurement frequency. In the current study, we develop an automated solution to extract forest inventory parameters at individual tree level from TLS data by using random sample consensus (RANSAC)-based circle fitting algorithm. The method was evaluated on both single- and multiscan data by characterizing four circular plots of radius 20 m in dry deciduous forests of Betual, Madhya Pradesh (India). Over all the plots, tree detection rates of 75% and 97% were obtained using single- and multi-scan TLS data respectively. Tree detection rates were significantly affected by increase in distance from the scanner, in single-scan approach when compared to multi-scan approach. Field based DBH measurements correlated well using both single (R2 = 0.96) and multiple scans (R2 = 0.99). The DBH estimates from multi-scan TLS data resulted in low root-mean-square error (RMSE) of 2.2 cm compared to that of 4.1 cm using single-scan. Further, tree heights were extracted from TLS data and validated with selectively measured trees on field (R2 = 0.98; N = 65). The RMSE of tree height was estimated to be 1.65 m. The current results show the potential use of TLS in automatically deriving forest inventory parameters with reliable accuracy at individual tree level.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Orthogonal time frequency space (OTFS) waveform based millimeter wave (mmWave) MIMO systems are capable of achieving high data rates in high-mobility scenarios. Hence, transceivers are designed for ...both analog beamforming (AB) and hybrid beamforming (HB), where we commence by deriving the delay-Doppler (DD)-domain input-output relationship considering a delay-Doppler-angular domain channel model. Subsequently, a novel two-stage procedure is developed for transmit beamformer (TBF)/ precoder (TPC) and receiver combiner (RC) design, and for estimating the DD-domain's equivalent channel state information (CSI). The key feature of the proposed framework is that the RF TBF/ TPC and RC design maximizes the directional beamforming gains. It is also demonstrated that the low-dimensional baseband CSI of the DD-domain becomes sparse for mmWave-AB MIMO OTFS systems, and block-sparse for mmWave-HB MIMO OTFS systems. Subsequently, Bayesian learning (BL) and block-sparse BL (BS-BL) solutions are developed for improved CSI estimation. We also derive the Bayesian Cramer-Rao lower bounds (BCRLB) for benchmarking the mean-squared-error (MSE) of the CSI estimates. Finally, our simulation results demonstrate the improved efficacy of the proposed transceiver designs and confirm the enhanced CSI estimation performance of the BL-based schemes over other competing sparse signal recovery schemes.
Efforts to identify and target glioblastoma (GBM) drivers have primarily focused on receptor tyrosine kinases (RTKs). Clinical benefits, however, have been elusive. Here, we identify an SRY-related ...box 2 (SOX2) transcriptional regulatory network that is independent of upstream RTKs and capable of driving glioma-initiating cells. We identified oligodendrocyte lineage transcription factor 2 (OLIG2) and zinc-finger E-box binding homeobox 1 (ZEB1), which are frequently co-expressed irrespective of driver mutations, as potential SOX2 targets. In murine glioma models, we show that different combinations of tumor suppressor and oncogene mutations can activate Sox2, Olig2, and Zeb1 expression. We demonstrate that ectopic co-expression of the three transcription factors can transform tumor-suppressor-deficient astrocytes into glioma-initiating cells in the absence of an upstream RTK oncogene. Finally, we demonstrate that the transcriptional inhibitor mithramycin downregulates SOX2 and its target genes, resulting in markedly reduced proliferation of GBM cells in vivo.
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•Sox2, Olig2, and Zeb1 expression is increased in glioma-initiating cells•These transcription factors are expressed irrespective of putative GBM oncogenes•Sox2, Olig2, and Zeb1 expression transforms tumor-suppressor-deficient astrocytes•Mithramycin inhibits Sox2, Olig2, and Zeb1 expression and GBM cell proliferation
Singh et al. report that a set of three transcription factors, Sox2, Olig2, and Zeb1, is an ultimate driver of glioblastoma. These factors are coordinately expressed in glioblastoma, induced by different oncogenic mutations, and their ectopic co-expression can transform immortalized astrocytes.
Constitutive relations and field equations are developed for an isotropic linear micropolar thermoelastic material with voids within the context of Eringen's theory of nonlocal elasticity. It is ...found that six plane waves may propagate in this medium consisting of four sets of coupled dilatational waves and two sets of coupled transverse waves. All the waves are found to be affected by the nonlocality of the medium, however, the sets of coupled transverse waves do not depend on the presence of thermal and void parameters in the medium. The dispersion relation yielding the speeds of coupled dilatational waves is analyzed, in particular, and several earlier known results are recovered from the present formulation. Numerical computations for a specific material are performed to clarify the effects of wave characteristics in detail. The computational results are displayed through graphs and explained.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Conservation agriculture (CA) technologies involve minimum soil disturbance, permanent soil cover through crop residues or cover crops, and crop rotations for achieving higher productivity. In India, ...efforts to develop, refine and disseminate conservation-based agricultural technologies have been underway for nearly two decades and made significant progress since then even though there are several constraints that affect adoption of CA. Particularly, tremendous efforts have been made on no-till in wheat under a rice-wheat rotation in the Indo-Gangetic plains. There are more payoffs than tradeoffs for adoption of CA but the equilibrium among the two was understood by both adopters and promoters. The technologies of CA provide opportunities to reduce the cost of production, save water and nutrients, increase yields, increase crop diversification, improve efficient use of resources, and benefit the environment. However, there are still constraints for promotion of CA technologies, such as lack of appropriate seeders especially for small and medium scale farmers, competition of crop residues between CA use and livestock feeding, burning of crop residues, availability of skilled and scientific manpower and overcoming the bias or mindset about tillage. The need to develop the policy frame and strategies is urgent to promote CA in the region. This article reviews the emerging concerns due to continuous adoption of conventional agriculture systems, and analyses the constraints, prospects, policy issues and research needs for conservation agriculture in India.
The work presented in this paper demonstrates an experimental path to improve the performance of a screen-printed flexible thermoelectric generator through optimization of leg materials, geometrical ...and structural parameters of the leg, and the viscosity of screen-printed ink. A thin and porous screen-printed leg structure improves the Seebeck coefficient and power output by 11.53 and 8.52 times, respectively than a thick and denser leg structure. A trapezoidal design increases the Seebeck coefficient, and power output by 2.72 and 3.82 times, respectively, compared with a rectangular leg structure. The observed increment in the power output using silver as contact material is about 2.17 times higher than graphene. Screen ink with higher ink viscosity results in a 47 % reduction of transient thermal conductivity and an increased power factor by 20.33 times. The rectangular leg produces the maximum power factor of 1.30 × 10−12 µWmm−2K−2. The improvement possible in the power output by controlling the leg structure's porosity is around 752.71 %. The result indicates that optimization of ink viscosity and porosity of ink film has significant influence in enhancing the performance of FTEG than its leg shapes and material properties.
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•Performance optimization of PANI/Graphite based screen printed FTEG is developed.•Trapezoidal leg shape is preferable over rectangular to enhance the power output.•Influence of ink viscosity is prominent than leg geometry on FTEG performance.•The higher electrical resistance of contact material enhances the voltage output.•Porous ink film reduced thermal conductivity and enhanced power output.
αB-crystallin (αB) is known as an intracellular Golgi membrane-associated small heat shock protein. Elevated levels of this protein have been linked with a myriad of neurodegenerative pathologies ...including Alzheimer disease, multiple sclerosis, and age-related macular degeneration. The membrane association of αB has been known for more than 3 decades, yet its physiological import has remained unexplained. In this investigation we show that αB is secreted from human adult retinal pigment epithelial cells via microvesicles (exosomes), independent of the endoplasmic reticulum-Golgi protein export pathway. The presence of αB in these lipoprotein structures was confirmed by its susceptibility to digestion by proteinase K only when exosomes were exposed to Triton X-100. Transmission electron microscopy was used to localize αB in immunogold-labeled intact and permeabilized microvesicles. The saucer-shaped exosomes, with a median diameter of 100–200 nm, were characterized by the presence of flotillin-1, α-enolase, and Hsp70, the same proteins that associate with detergent-resistant membrane microdomains (DRMs), which are known to be involved in their biogenesis. Notably, using polarized adult retinal pigment epithelial cells, we show that the secretion of αB is predominantly apical. Using OptiPrep gradients we demonstrate that αB resides in the DRM fraction. The secretion of αB is inhibited by the cholesterol-depleting drug, methyl β-cyclodextrin, suggesting that the physiological function of this protein and the regulation of its export through exosomes may reside in its association with DRMs/lipid rafts.
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