A Robust Beamformer Based on Weighted Sparse Constraint

Applying a sparse constraint on the beam pattern has been suggested to suppress the sidelobe level of a minimum variance distortionless response (MVDR) beamformer. In this letter, we introduce a weighted sparse constraint in the beamformer design to provide a lower sidelobe level and deeper nulls for interference avoidance, as compared with a conventional MVDR beamformer. The proposed beamformer also shows improved robustness against the mismatch between the steering angle and the direction of arrival (DOA) of the desired signal, caused by imperfect estimation of DOA.Comment: 4 pages, 2 figure

Power-Efficient Ultra-Wideband Waveform Design Considering Radio Channel Effects

This paper presents a power-efficient mask-constrained ultra-wideband (UWB) waveform design with radio channel effects taken into consideration. Based on a finite impulse response (FIR) filter, we develop a convex optimization model with respect to the autocorrelation of the filter coefficients to optimize the transmitted signal power spectrum, subject to a regulatory emission mask. To improve power efficiency, effects of transmitter radio frequency (RF) components are included in the optimization of the transmitter-output waveform, and radio propagation effects are considered for optimizing at the receiver. Optimum coefficients of the FIR filter are obtained through spectral factorization of their autocorrelations. Simulation results show that the proposed method is able to maximize the transmitted UWB signal power under mask constraints set by regulatory authorities, while mitigating the power loss caused by channel attenuations.Comment: 14 pages, 2 figures, 1 tabl

Interprofessional Collaboration in Addressing Diet as a Common Risk Factor: A Qualitative Study

Background: Unhealthy diet is a common risk factor threatening dental and general health. Conflicting dietary advice persists among different healthcare professions, despite some shared goals, causing mystification to patients and the public. This qualitative study aimed to understand the perspectives of dentists, physicians, and dietitians in targeting unhealthy diet as a common risk factor, their experiences and barriers in addressing conflicting dietary advice, and possible ways for improving cross-professional coordination.Methods and Findings: A purposive sample of 40 dentists, physicians, and dieticians was recruited from different service sectors and joined in semi-structured interviews, which were subjected to thematic content analysis. Participants supported the common risk factor approach and suggested improving cross-professional cooperation by maximizing potentials of multidisciplinary care, engaging auxiliary/allied staff, refining electronic systems, and incorporating cutting-edge communication technologies. Inconsistent dietary advice stemmed from different treatment focuses and lack of mutual understanding and well-followed guidelines. Inconsistencies can be resolved by striking a balance for the patient’s best interest, well-informing patients, respecting patients’ autonomy, acquiring cross-professional knowledge, and conforming to shared guidelines.Conclusions: Views solicited from three healthcare professions endorsed the importance of cross-professional partnership in preventing/managing dietrelated health problems. Educators, professional bodies, and administrators share the responsibility to dispel conflicting health messages and promote better practice in dietary counselling

Soil water distribution on different number of growing years of alfalfa pasture in the Loess Plateau of Northwest China

The alfalfa pastureland in the semiarid Loess Plateau region of Northwest China usually has dry soil layers. We studied the soil water variations on alfalfa (Medicago sativa L.) grassland with different number of growing years. Seven growing years of alfalfa grassland were chosen in this study: (1) 4-year-old, (2) 6-year-old, (3) 8-year-old, (4) 12-year-old, (5) 14-year-old, (6)18-year-old and (7) 26-year-old. The results showed that the highest soil water content, 12.0 -17.15%, with different number of growing years of alfalfa grassland occurred in 80 -100 cm soil layer, but gradually became stable below 300 cm soil layer. The soil water content with 4, 6 and 8 year alfalfa grassland was in the range of 13.66 - 14.76%, with 12 and 14 year ranged within 11.76 -1 1.87% and with 18 and 26 year within 10.5%. We also found that in 0 - 1000 cm soil layer, the soil water content with different number of growing years of alfalfa grassland had differences due to different soil water conditions and water-supplying capability. The soil water content with 4 and 6 year were 13.85 and 14.22%, respectively, with 8, 12 and 14 year were 12.98, 11.25 and 11.22%, respectively, and with 18 and 26 year were 10.27 and 10.76%, respectively. After alfalfa grew for >18 years, the annual recovery of its soil water at 0 - 200 cm soil depth was 1.49%, whereas the soil water with 18 and 26 year alfalfa pastureland at 200 - 1000 cm soil depth was only 10.10%, dry soil layers occurring in alfalfa pasture. The dry soil layer of alfalfa grassland appears at 160 - 600 cm soil depth in the Loess Plateau. We found that at 250 - 350 cm soil depth, the soil water content with 4 and 6 year alfalfa grassland was in the range of 10.23 - 10.48%, presenting slightly dry soil layer and for more than 8 year, alfalfa was in the range of 7.78 - 8.48%, presenting moderately dry soil layer. In summary, the soil water use of alfalfa would grow with the number of growing years and the depth of desiccated layers will become intensified and thicker.Keywords: Alfalfa grassland, different number of growing years, soil water content, dry soil layers, Loess Plateau of ChinaAfrican Journal of Biotechnology Vol. 9(35), pp. 5686-5693, 30 August, 201

Characterization of the complete mitochondrial genome and phylogenetic analysis of Pelodiscus sinensis, a mutant Chinese soft-shell turtle

The Chinese soft-shell turtle (Pelodiscus sinensis, Testudines: Pelodiscus) shows geographical variation, and one strain is the inked turtle. Wild population numbers have dropped substantially during the past decades, and the species is now classed as vulnerable. However, little genetic data exists so this study aimed to sequence and analyze the complete mitochondrial genome. The circular double-stranded genome is 17,145 bp in length and contains 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes, an L-strand replication origin and a control region. The base composition is 35.5% A, 27.3% T, 11.8% G and 25.4% C, with an AT content of 62.8%. Trionychidae species were divided into two clades based on phylogenetic analysis, and the closest genetic distance was between Trionyx axenaria and P. sinensis. This study provides basic genetic data for future studies on conservation biology, phylogenetic and evolutionary analysis of this inked strain of the Chinese soft-shell turtle.</p

The Frontal Area with Higher Frequency Response Is the Principal Feature of Laser-Evoked Potentials in Rats with Chronic Inflammatory Pain: A Parallel Factor Analysis Study

Chronic pain is a pathological developing course of pain. In clinic, an objective indicator is needed for diagnosing and better controlling chronic pain. The abnormal neural responses in chronic pain are reflected by multiple event-related potentials (ERPs) in time, frequency, and location domain, respectively. However, multiple changes in ERPs are not applicable in clinic. So, the principal feature covered the most informative changes extracted from these three domains of ERP during the development of chronic pain is needed. In the present study, a parallel factor analysis method was employed to extract time–frequency–channel features of laser-evoked potential (LEP) simultaneously from rats with chronic inflammatory pain. Results showed that the main feature of LEP in channel domain locates in the frontal brain region in rats with chronic inflammatory pain while in the parietal brain region in control rats. In the frequency domain, the main frequency of LEP was significantly higher in chronic inflammatory pain rats than that in control rats. These findings indicate that the frontal region with higher frequency response to nociceptive information is the principal feature in the chronic pain state. Our study provided not only a principal feature of LEP but also a promising strategy for chronic pain, which is potential for clinic application

Probing and Tuning the Spin Textures of the K and Q Valleys in Few-Layer MoS2

The strong spin-orbit coupling along with broken inversion symmetry in transition metal dichalcogenides (TMDs) results in spin polarized valleys, which are the origins of many interesting properties such as Ising superconductivity, circular dichroism, valley Hall effect, etc. Herein, it is shown that encapsulating few-layer MoS2 between hexagonal boron nitride (h-BN) and gating the electrical contacts by ionic liquid pronounce Shubnikov-de Haas (SdH) oscillations in magnetoresistance. Notably, the SdH oscillations remain unchanged in tilted magnetic fields, demonstrating that the spins of the Q/Q ' valleys are firmly locked to the out-of-plane direction; therefore, Zeeman energy is insensitive to the in-plane magnetic field. Ionic liquid gating induces superconductivity on the surface of unencapsulated MoS2. The spins of Cooper pairs are strongly pinned to the out-of-plane direction by the effective Zeeman field, hence are protected from being realigned by an in-plane magnetic field, namely, Ising protection. As a result, superconductivity persists in an in-plane magnetic field up to 14 T, in which T-c only decreases by approximate to 0.3 K from T-c0 as approximate to 7 K. By applying back gate, the strength of Ising protection can be effectively tuned, where an increase in 70% is observed when back gate changes from +90 to -90 V

A Flip-Over Plasmonic Structure for Photoluminescence Enhancement of Encapsulated WS₂ Monolayers

Transition metal dichalcogenide (TMD) monolayers, with their direct band gaps, have attracted wide attention from the fields of photonics and optoelectronics. However, monolayer semiconducting TMDs generally suffer from low excitation absorption and emission efficiency, limiting their further applications. Here a flip-over plasmonic structure comprised of silver nano-disk arrays supporting a WS2 monolayer sandwiched by hexagonal boron nitride (h-BN) layers is demonstrated. The flip-over configuration optimizes the optical process with a free excitation/emission path from the top and a strong plasmonic interaction from the bottom. As a result, the photoluminescence from the TMD monolayers can be greatly enhanced more than tenfold by optimizing the metasurface, which can be further improved nearly tenfold by optimizing the thickness of bottom h-BN. This study shows the advantages of using the flip-over structure, where the plasmonic interaction between the metasurface and TMDs can be tuned by introducing optimized plasmonic arrays and h-BN layers with suitable thickness. This hybrid device configuration paves a reliable platform to study the light–matter interaction, achieving highly efficient plasmonic TMD devices