Compressive sampling matching pursuit (CoSaMP), as a conventional algorithm requiring system sparsity and sensitive to step size, was improved in this paper by approximating the sparsity with ...adaptive variable step size. In the proposed algorithm (CoSaMP with variable step size abbreviated as Vss-CoSaMP), the idea of approximating sparsity with adaptive step size was borrowed from the sparsity adaptive matching pursuit (SAMP) algorithm to determine the sparsity for the CoSaMP algorithm. The applicability of the CoSaMP algorithm was therefore expanded considerably. On this basis, a step size reduction was added as the iteration termination condition of an orthogonal frequency division multiplexing (OFDM) system. An adaptive variable step size algorithm was then put forward to address the CoSaMP algorithm’s sensitivity to step size. It could realize the required precision at different initial step sizes. A simulation was carried out to analyze the influence of pilot number and step size in an OFDM system on the algorithm. The algorithms, including SAMP, CoSaMP, and Vss-CoSaMP, were compared with two sparse channels, revealing that the Vss-CoSaMP algorithm overcame the problem of the CoSaMP algorithm, that is, the impossibility to forecast the channel sparsity. With the adaptive step size, the proposed algorithm could reach and achieve better accuracy than the CoSaMP algorithm. Additionally, the proposed algorithm was superior over the SAMP algorithm in terms of reconstruction, mean square error (MSE), and bit error ratio (BER).
With the development of wireless communication technology, cognitive radio needs to solve the spectrum sensing problem of wideband wireless signals. Due to performance limitation of electronic ...components, it is difficult to complete spectrum sensing of wideband wireless signals at once. Therefore, it is required that the wideband wireless signal has to be split into a set of sub-bands before the further signal processing. However, the sequence of sub-band perception has become one of the important factors, which deeply-impact wideband spectrum sensing performance. In this paper, we develop a novel approach for sub-band selection through the non-stationary multi-arm bandit (NS-MAB) model. This approach is based on a well-known order optimal policy for NS-MAB mode called discounted upper confidence bound (D-UCB) policy. In this paper, according to different application requirements, various discount functions and exploration bonuses of D-UCB are designed, which are taken as the parameters of the policy proposed in this paper. Our simulation result demonstrates that the proposed policy can provide lower cumulative regret than other existing state-of-the-art policies for sub-band selection of wideband spectrum sensing.
Aims: This study aimed to examine the relationship between physical performance and peripheral artery disease (PAD) in different age groups of Chinese older adults.Methods: We enrolled 1357 ...relatively healthy ≥ 65 years old participants of Chinese ethnicity. We classified the participants into two age categories, the pre-old group (65–74 years, n=968) and the old group (≥ 75 years, n=389). We assessed the cross-sectional association of the ankle–brachial index (ABI), which is used for the classification of patients with PAD (ABI ≤ 0.9). Physical performance mainly focused on muscle strength, mobility, and balance, which were measured via hand grip, 4 m walking speed, and the Timed Up and Go Test. Results: A total of 125 (9.2%) patients met the diagnostic criteria and were defined as having PAD. After multivariate adjustment, we found that grip strength and 4 m walking speed were correlated negatively with PAD (odds ratio (OR)=0.953, 95% confidence interval (CI)=0.919–0.989; OR=0.296, 95% CI=0.093–0.945) in pre-old participants, whereas balance (OR=1.058, 95% CI=1.007–1.112) was correlated positively with PAD only in older participants. Conclusion: Our study further confirmed the association between physical performance and PAD in community-dwelling older Chinese adults. Muscle strength and mobility correlated negatively with PAD, and balance was positively associated with PAD in older participants. These findings might help with better early screening and management of PAD.
Noninvasive prenatal screening (NIPS) based on cell-free fetal DNA (cffDNA) has rapidly been applied into clinic. However, the reliability of this method largely depends on the concentration of ...cffDNA in the maternal plasma. The chance of test failure results or false negative results would increase when cffDNA fraction is low. In this study, we set out to develop a method to enrich the cffDNA for NIPS based on the size difference between cell-free DNA (cfDNA) of fetal origin and maternal origin, and to evaluate whether the new NIPS method can improve the test quality.
We utilized 10,000 previous NIPS data to optimize a size-selection strategy for enrichment. Then, we retrospectively performed our new NIPS method with cffDNA enrichment on the 1415 NIPS samples, including 1404 routine cases and 11 false negative cases, and compared the results to the original NIPS results.
The 10,000 NIPS data revealed the fetal fraction in short cfDNA fragments (< 160 bp) is significantly higher. By using our new NIPS strategy on the 1404 routine cases, the fetal fraction increased from 11.3 ± 4.2 to 22.6 ± 6.6%, and the new method performed a significant decrease of test-failure rate (0.1% vs 0.7%, P < 0.01). Moreover, in 45.5% (5/11) of the false negative cases, fetal trisomies were successfully detected by our new NIPS method.
We developed an effective method to enrich cffDNA for NIPS, which shows an increased success rate and a reduced chance of false negative comparing to the ordinary NIPS method.
The cognitive wireless sensor network (CWSN) is an important development direction of wireless sensor networks (WSNs), and spectrum sensing technology is an essential prerequisite for CWSN to achieve ...spectrum sharing. However, the existing non-cooperative narrowband spectrum sensing technology has difficulty meeting the application requirements of CWSN at present. In this paper, we present a non-cooperative spectrum sensing algorithm for CWSN, which combines the multi-resolution technique, phase space reconstruction method, and singular spectrum entropy method to sense the spectrum of narrowband wireless signals. Simulation results validate that this algorithm can greatly improve the detection probability at a low signal-to-noise ratio (SNR) (from -19dB to -12dB), and the detector can quickly achieve the best detection performance as the SNR increases. This algorithm could promote the development of CWSN and the application of WSNs.
We tuned the lower critical solution temperature (LCST) of amphiphilic poly(N-isopropylacrylamide) (PNIPAAm) via copolymerization with a hydrophilic comonomer of N-hydroxymethyl acrylamide (NHMAAm). ...A series of copolymers P(NIPAAm-co-NHMAAm) were synthesized by atom transfer radical polymerization (ATRP) using CuBr/(N,N,N',N',N''-Pentamethyldiethylenetriamine) (PMDETA) as a catalyst system and 2-bromo ethyl isobutyrate (EBiB) as an initiator. The copolymers were well characterized by Fourier transform infrared spectroscopy (FT-IR), 1H Nuclear magnetic resonance (NMR), and Thermogravimetric analysis (TGA). The copolymers followed a simple rule in their thermosensitive behaviors and have a linear increase in the LCST as a function of NHMAAm mol%. The thermosensitive properties of the copolymer films were investigated and demonstrated hydrophilic-hydrophobic transitions. Finally, the copolymer was grafted onto cotton fabrics using citric acid (CA) as a crosslinking agent and sodium hypophosphite (SHP) as a catalyst following a two dipping, two padding process. The large number of hydroxyl groups in the copolymer makes grafting convenient and firm. The grafted cotton fabrics show obvious thermosensitive behaviors. The results demonstrate that the cotton fabrics become more hydrophobic when the temperature is higher than the LCST. This study presents a valuable route towards temperature-responsive smart textiles and their potential applications.
Dams worldwide have significantly altered the composition of riparian forests. However, research on the functional traits of dominant herbs experiencing flooding stress due to dam impoundment remains ...limited. Given the high plasticity of leaf traits and their susceptibility to environmental influences, this study focuses on riparian herbs along the Three Gorges Hydro‐Fluctuation Zone (TGHFZ). Specifically, it investigates how six leaf physiological traits of leading herbs—carbon, nitrogen, phosphorus, and their stoichiometric ratios—adapt to periodic flooding in the TGHFZ using cluster analysis, one‐way analysis of variance (ANOVA), multiple comparisons, Pearson correlation analysis, and principal component analysis (PCA). We categorized 25 dominant herb species into three plant functional types (PFTs), noting that species from the same family tended to fall into the same PFT. Notably, leaf carbon content (LCC) exhibited no significant differences across various PFTs or altitudes. Within riparian forests, different PFTs employ distinct adaptation strategies: PFT‐I herbs invest in structural components to enhance stress resistance; PFT‐II, mostly comprising gramineous plants, responds to prolonged flooding by rapid growth above the water; and PFT‐III, encompassing nearly all Compositae and annual plants, responds to prolonged flooding with vigorous rhizome growth and seed production. Soil water content (SWC) emerges as the primary environmental factor influencing dominant herb growth in the TGHFZ. By studying the response of leaf physiological traits in dominant plants to artificial flooding, we intend to reveal the survival mechanisms of plants under adverse conditions and lay the foundation for vegetation restoration in the TGHFZ.
Gramineae and Compositae families were significantly represented among the 25 dominant herb species. Annuals and perennials were distributed evenly among herb functional types in riparian forests. Variations in leaf traits among different functional types reveal complex and varied responses to changes in flooding intensity. Plant growth was primarily affected by nitrogen in riparian forests. Soil moisture content dominated environmental factors for herb species growth within the riparian zone.
The contact mechanism for joint surfaces is important for predicting the loading process and dynamic properties of precision machinery products. A multiasperity model considering the lateral ...interaction and coalescence of contact regions with oblique asperity contact, the interacting and coalescing Hertzian asperities (ICHA) model, is introduced in this work. Contact angle
α
and radius of curvature
R
(
r
)
are vital parameters that are directly calculated based on grid points measured from the milling and grinding surfaces. Numerical simulations of
α
and
R
(
r
)
were analysed. The results show that the proposed model is more effective at improving the contact area versus force relationship than various asperity models for low and middle contact forces.
α
and
R
(
r
)
follow a Gaussian distribution. Because of the existence of coalescence, they decrease with increasing contact force. Furthermore, the
α
and
R
(
r
)
in the startup phase are crucial data that can be used to judge the effects of oblique asperity contact. They are greatly influenced by fractal dimension
D
and fractal roughness G. From the comparisons with the surfaces generated by Weierstrass-Mandelbrot function, it is suggested that to obtain an accurate contact prediction in the loading process, oblique contact is as important as lateral interaction and coalescence.
Abstract
We propose an optical-acoustic means to excite
broadband
terahertz antiferromagnetic (AFM) spin wave in a metal/insulator/antiferromagnet heterostructure. The AFM spin wave is excited by an ...ultrafast strain wave triggered by a femtosecond pulsed laser based on photoacoustic conversion. This spin wave comprises an AFM exchange spin wave and a magnetoelastic spin wave. Their dispersion curves are overlapped in a wide frequency range by manipulating the Dzyaloshinskii–Moriya interaction, which is accompanied by lifting the degeneration of the spin-wave modes with opposite chirality. This optical-acoustic excitation of spin waves exploits the laser-induced ultrafast strain waves and avoids the thermal effect from the laser. It paves a way to develop novel AFM devices that can apply for ultrafast information processing and communication.
Clonorchis sinensis (C. sinensis), an important food-borne parasite that inhabits the intrahepatic bile duct and causes clonorchiasis, is of interest to both the public health field and the ...scientific research community. To learn more about the migration, parasitism and pathogenesis of C. sinensis at the molecular level, the present study developed an upgraded genomic assembly and annotation by sequencing paired-end and mate-paired libraries. We also performed transcriptome sequence analyses on multiple C. sinensis tissues (sucker, muscle, ovary and testis). Genes encoding molecules involved in responses to stimuli and muscle-related development were abundantly expressed in the oral sucker. Compared with other species, genes encoding molecules that facilitate the recognition and transport of cholesterol were observed in high copy numbers in the genome and were highly expressed in the oral sucker. Genes encoding transporters for fatty acids, glucose, amino acids and oxygen were also highly expressed, along with other molecules involved in metabolizing these substrates. All genes involved in energy metabolism pathways, including the β-oxidation of fatty acids, the citrate cycle, oxidative phosphorylation, and fumarate reduction, were expressed in the adults. Finally, we also provide valuable insights into the mechanism underlying the process of pathogenesis by characterizing the secretome of C. sinensis. The characterization and elaborate analysis of the upgraded genome and the tissue transcriptomes not only form a detailed and fundamental C. sinensis resource but also provide novel insights into the physiology and pathogenesis of C. sinensis. We anticipate that this work will aid the development of innovative strategies for the prevention and control of clonorchiasis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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