An identification of the tolerable time-interleaved analog-to-digital converter timing mismatch level in high-speed orthogonal frequency division multiplexing systems

High-speed Terahertz communication systems has recently employed orthogonal frequency division multiplexing approach as it provides high spectral efficiency and avoids inter-symbol interference caused by dispersive channels. Such high-speed systems require extremely high-sampling time-interleaved analog-to-digital converters at the receiver. However, timing mismatch of time-interleaved analog-to-digital converters significantly causes system performance degradation. In this paper, to avoid such performance degradation induced by timing mismatch, we theoretically determine maximum tolerable mismatch levels for orthogonal frequency division multiplexing communication systems. To obtain these levels, we first propose an analytical method to derive the bit error rate formula for quadrature and pulse amplitude modulations in Rayleigh fading channels, assuming binary reflected gray code (BRGC) mapping. Further, from the derived bit error rate (BER) expressions, we reveal a threshold of timing mismatch level for which error floors produced by the mismatch will be smaller than a given BER. Simulation results demonstrate that if we preserve mismatch level smaller than 25% of this obtained threshold, the BER performance degradation is smaller than 0.5 dB as compared to the case without timing mismatch

The Combined Use of Pediococcus pentosaceus and Fructooligosaccharide Improves Growth Performance, Immune Response, and Resistance of Whiteleg Shrimp Litopenaeus vannamei Against Vibrio parahaemolyticus

In this study, we evaluated the effect of probiotic bacteria Pediococcus pentosaceus supplemented at different inclusion levels in a control diet [basal diet containing 0.5% fructooligosaccharide (FOS)] on the growth performance, feed conversion ratio, immune response, and the disease resistance of whiteleg shrimp Litopenaeus vannamei juveniles against Vibrio parahaemolyticus. A control diet with 0.5% FOS but without P. pentosaceus supplementation (Control) was prepared. In addition, three other test diets were also formulated: control diet supplemented with P. pentosaceus at (i) 1 x 10(6) cfu g(-1) diet (P1), (ii) 1 x 10(7) cfu g(-1) diet (P2), or (iii) 1 x 10(8) cfu g(-1) diet (P3). After a 60-day feeding trial, the experimental shrimps were challenged with V. parahaemolyticus. The results showed that dietary supplementation of P. pentosaceus significantly improved the growth performance and immune responses of L. vannamei juveniles. The juveniles that were fed with a P2 or P3 diet recorded the maximum increase in the final body weight, final length, weight gain, and survival rate. The total hemocyte counts, phenoloxidase, and lysozyme activity of shrimp fed with either of these two diets were significantly enhanced. The results also showed that juveniles fed with a P2 or P3 diet exhibited significantly lower mortality when challenged with V. parahaemolyticus. Overall results suggested that a combination of P. pentosaceus at the inclusion level of 1 x 10(7) cfu g(-1) diet (P2) and 0.5% FOS could be considered as a potential synbiotic formulation for improving the growth, health, and robustness of L. vannamei

TỔNG HỢP VÀ ĐẶC TRƯNG VẬT LIỆU NANO ZnFe2O4

In this work, the spinel-type ZnFe2O4 material was successfully synthesized via the hydrothermal method combined with calcination. Several factors influencing the synthesis, such as hydrothermal time, hydrothermal temperature, and calcination temperature, were studied. The material was characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and nitrogen adsorption/desorption isotherms (BET). The results indicate that the highly ordered crystalline form of spinel ZnFe2O4 was synthesized under the following conditions: hydrothermal temperature of 120 °C, hydrothermal time of 24 h, and calcination temperature of 500 °C.Trong nghiên cứu này, vật liệu nano ZnFe2O4 được tổng hợp thành công bằng phương pháp thủy nhiệt kết hợp với nung. Các yếu tố ảnh hưởng đến quá trình tổng hợp vật liệu như thời gian thủy nhiệt, nhiệt độ thủy nhiệt và nhiệt độ nung đã được khảo sát. Vật liệu tổng hợp được đặc trưng bằng phương pháp nhiễu xạ tia X (XRD), hiển vi điện tử quét (SEM), phổ hồng ngoại (FT-IR) và hấp phụ/khử hấp phụ ni tơ (BET). Kết quả cho thấy tinh thể spinel ZnFe2O4 có trật tự cao được tổng hợp ở nhiệt độ thủy nhiệt 120 °C, thời gian thủy nhiệt 24 h và nhiệt độ nung 500 °C

The effect of trust on consumers’ online purchase intention: An integration of TAM and TPB

The aim of this research is to investigate the effects of different factors on Vietnamese consumers’ online shopping intention based on Technology Acceptance Model (TAM) and Theory of Planned Behavior (TPB). A questionnaire was designed and sent directly to the respondents through the Internet. After 5 months period of collecting the necessary data, 423 valid replies were collected and analyzed. The data were analyzed in accordance with exploratory factor analysis (EFA) and multiple regression techniques. The results show that perceived usefulness, perceived ease of use, attitude, subjective norm and trust had positive effects on consumers’ online shopping intention

Effects of propidium monoazide (PMA) treatment on mycobiome and bacteriome analysis of cystic fibrosis airways during exacerbation

Introduction and Purpose : Propidium monoazide (PMA)-pretreatment has increasingly been applied to remove the bias from dead or damaged cell artefacts, which could impact the microbiota analysis by high-throughput sequencing. Our study aimed to determine whether a PMA-pretreatment coupled with high-throughput sequencing analysis provides a different picture of the airway mycobiome and bacteriome. Results and Discussion : We compared deep-sequencing data of mycobiota and microbiota of 15 sputum samples from 5 cystic fibrosis (CF) patients with and without prior PMA-treatment of the DNA-extracts. PMA-pretreatment had no significant effect on the entire and abundant bacterial community (genera expressed as operational taxonomic units (OTUs) with a relative abundance greater than or equal to 1%), but caused a significant difference in the intermediate community (less than 1%) when analyzing the alpha biodiversity Simpson index (p = 0.03). Regarding PMA impact on the airway mycobiota evaluated for the first time here; no significant differences in alpha diversity indexes between PMA-treated and untreated samples were observed. Regarding beta diversity analysis, the intermediate communities also differed more dramatically than the total and abundant ones when studying both mycobiome and bacteriome. Our results showed that only the intermediate (or low abundance) population diversity is impacted by PMA-treatment, and therefore that abundant taxa are mostly viable during acute exacerbation in CF. Given such a cumbersome protocol (PMA-pretreatment coupled with high-throughput sequencing), we discuss its potential interest within the follow-up of CF patients. Further studies using PMA-pretreatment are warranted to improve our "omic" knowledge of the CF airways

Factors Affecting Consumers’ Impulsive Purchasing Behavior in Circle K Convenience Stores in Hanoi, Vietnam

Impulsive purchasing behavior has been observed as one of the important studies conducted by marketers and researchers, as impulse buying has become a prevalent phenomenon in every retail format. The study was conducted to assess factors affecting consumers’ impulsive purchasing behavior in Circle K convenience stores in Hanoi, Vietnam. After reviewing a group of previous studies, the authors indicated 05 factors that affected consumers' impulsive purchasing behavior including impulsiveness, instant gratification, visual appeal, promotions and money availability. The study had selected 05 experts in the field of economics to conduct the expert interview. Moreover, the research team had also handed out the questionnaire and received 310 observations. Specifically, Impulsiveness had the strongest influence on the impulsive purchasing behavior of Circle K’s consumers in Hanoi. Keywords: factors, Impulsive purchasing behavior, Circle K convenience stores DOI: 10.7176/JESD/14-8-03 Publication date: April 30th 2023

Investigating the diversity of resistant starch in Vietnamese rice collection

The rapid increase of obesity and type 2 diabetes has recently posed an enormous burden on the healthcare system worldwide. Resistant starch (RS) in rice can escape digestion by enzymes in the small intestine, making its calories unavailable for cells to use. As a result, RS can be used by diabetes patients to prevent diabetes and for obese individuals who do not want extra energy. In our study, 75 Vietnamese rice accessions originating from diverse ecosystems were chosen as plant materials to investigate the diversity of RS content in this collection. The Megazyme kit was used to measure the amount of RS. The release of quinonimine was measured using a spectrophotometer at 510 nm. The results showed that approximately 70% of Vietnamese rice accessions had RS content ranging from 0.015 to 0.2% while only 4% of samples had RS content ranging from 0.6 to 0.8%. The Indica subgroups had significantly higher RS content than the Japonica subgroup. Higher RS content was found in medium- and short- grain rice rather than in long grain. Finally, rice plants grown in rainfed lowlands (RL) and irrigated ecosystems had higher RS content than those grown under mangrove and upland ecosystems. Our results firstly give information about the diversity of RS in Vietnamese rice and secondly may contribute to the field of nutrition by developing a suitable rice-based diet for patients with diabetes or obesity

Chaotic Compressed Sensing and Its Application to Magnetic Resonance Imaging

Fast image acquisition in magnetic resonance imaging (MRI) is important, due to the need to find ways that help relieve patient’s stress during MRI scans. Methods for fast MRI have been proposed, most notably among them are pMRI (parallel MRI), SWIFT (SWeep Imaging with Fourier Transformation), and compressed sensing (CS) based MRI. Although it promises to significantly reduce acquisition time, applying CS to MRI leads to difficulties with hardware design because of the randomness nature of the measurement matrix used by the conventional CS methods. In this paper, we propose a novel method that combines the above-mentioned three approaches for fast MRI by designing a compound measurement matrix from a series of single measurement matrices corresponding to pMRI, SWIFT, and CS. In our method, the CS measurement matrix is designed to be deterministic via chaotic systems. This chaotic compressed sensing (CCS) measurement matrix, while retaining most features of the random CS matrix, is simpler to realize in hardware. Several compound measurement matrices have been constructed and examined in this work, including CCS-MRI, CCS-pMRI, CCS-SWIFT, and CCS-pSWIFT. Simulation results showed that the proposed method allows an increase in the speed of the MRI acquisition process while not compromising the quality of the acquired MR images

Crystal structure and Hirshfield surface analysis of 4-phenyl-3-(thio-phen-3-ylmeth-yl)-1<i>H</i>-1,2,4-triazole-5(4<i>H</i>)-thione.

In the title compound, C13H11N3S2, the phenyl ring is twisted from the 1,2,4-triazole plane by 63.35 (9)° and by 47.35 (9)° from the thio-phene plane. In the crystal, chains of mol-ecules running along the c-axis direction are formed by N-H⋯S inter-actions [graph-set motif C(4)]. The 1,2,4-triazole and phenyl rings are involved in π-π stacking inter-actions [centroid-centroid distance = 3.4553 (10) Å]. The thio-phene ring is involved in C-H⋯S and C-H⋯π inter-actions. The inter-molecular inter-actions in the crystal packing were further analysed using Hirshfield surface analysis, which indicates that the most significant contacts are H⋯H (35.8%), followed by S⋯H/H⋯S (26.7%) and C⋯H/H⋯C (18.2%)