1,716 research outputs found

    Information similarity metrics in information security and forensics

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    We study two information similarity measures, relative entropy and the similarity metric, and methods for estimating them. Relative entropy can be readily estimated with existing algorithms based on compression. The similarity metric, based on algorithmic complexity, proves to be more difficult to estimate due to the fact that algorithmic complexity itself is not computable. We again turn to compression for estimating the similarity metric. Previous studies rely on the compression ratio as an indicator for choosing compressors to estimate the similarity metric. This assumption, however, is fundamentally flawed. We propose a new method to benchmark compressors for estimating the similarity metric. To demonstrate its use, we propose to quantify the security of a stegosystem using the similarity metric. Unlike other measures of steganographic security, the similarity metric is not only a true distance metric, but it is also universal in the sense that it is asymptotically minimal among all computable metrics between two objects. Therefore, it accounts for all similarities between two objects. In contrast, relative entropy, a widely accepted steganographic security definition, only takes into consideration the statistical similarity between two random variables. As an application, we present a general method for benchmarking stegosystems. The method is general in the sense that it is not restricted to any covertext medium and therefore, can be applied to a wide range of stegosystems. For demonstration, we analyze several image stegosystems using the newly proposed similarity metric as the security metric. The results show the true security limits of stegosystems regardless of the chosen security metric or the existence of steganalysis detectors. In other words, this makes it possible to show that a stegosystem with a large similarity metric is inherently insecure, even if it has not yet been broken

    Identification and Antibiotic Resistance Edwardsiella tarda from Clown Knifefish (Chitala chitala) in the Mekong Delta, Vietnam

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    This investigation is intended to isolate, identify, and assess the pathogenicity of Edwardsiella tarda, which originated from diseased clown knifefish. A total of 43 isolates were obtained from infected fish samples in Hau Giang and Dong Thap provinces of the Mekong Delta, Vietnam. Two isolates of DT37 and HG41 were identified as E. tarda by morphological, biochemical, and 16S rRNA gene sequencing. Experimental challenge studies revealed that isolate DT37 leads to 83.33% at a 108 CFU/ml concentration after 60 hours. Meanwhile, in isolate HG41, mortality reached 100% within 48 hours post-injection at the highest concentration of 108 CFU/ml. The challenged clown knifefish exhibited gross signs of abnormal swimming, skin ulcerations, and petechial hemorrhages in the body. Internally, ascites with hemoperitoneum, light-colored nodules on the liver, hemorrhagic kidneys, and splenomegaly were also recorded. The LD50 of two isolates, DT37 and HG41, was 4.89 × 105 and 4.07 × 105 CFU/ml, respectively. The antibiogram result showed that most of the isolates were highly susceptible to ampicillin (65%), enrofloxacin (85%), florfenicol (100%), flumequine (90%), cefotaxime (80%), and trimethoprim and sulfamethoxazole (70%). However, the bacterial isolates were highly resistant to doxycycline (75%) and streptomycin (100%)

    The Efficiency and the Performance of the Logistics Global Supply Chain Activities to Vietnam Exportation: an Empirical Case Study

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    Purpose: This research paper aims to determine the factors affecting the efficiency and logistics performance index (LPI) of Vietnam's exports to foreign partners during 2018-2022 are due to the impact of the COVID-19 pandemic.   Theoretical Framework: Based on the primary factors affecting the efficiency and performance of global supply chain activities in logistics for Vietnam's exports, including practical impact and logistics results of enterprises in Vietnam. Based on the primary factors affecting the efficiency and performance of global supply chain activities in logistics for Vietnam's exports, including (1). Customs efficiency (speed, simplicity and predictability of customs clearance procedures) (2). Quality of infrastructure related to trade and transport, including Roads, railways, ports, airports, warehouses and information technology ...(3). The level of ease when arranging to transport import and export goods with competitive prices (costs such as warehousing fees, port fees, tolls ... ) (4). Capacity and quality of logistics service providers ... (5). Ability to track and trace shipments. (6). Timeliness of the shipment to the destination within the specified time limit. The practical impact and logistics results of enterprises in Vietnam.   Method: The panel approach allows the authors to explore the heterogeneity in data across countries. Fixed effects (FE) and random effects (RE) models were used to estimate the model. Then, the Hausman test is carried out to decide which model is appropriate. The data were collected from 240 observations from Vietnam and 80 major export partner countries of Vietnam.   Findings: The research results show that the cost, time and capacity of providing logistics services have the most significant impact on Vietnam's exports.   Practical & social implications: Overall, to increase the efficiency and logistics efficiency of enterprises. The Vietnamese Government needs to cooperate and propose ideas to partner countries to improve logistics activities for exports from Vietnam. Logistics is beginning to play an increasingly important role in the competitiveness of economies.   Originality values: This study also confirms the sustainability of the extended gravity model using OLS and RE methods by substituting different variables for the country's logistics efficiency and solving the endogenous problem in the model while applying the regression method to industrial variables. We find that an 1% improvement in Vietnam's logistics would increase Vietnam's exports by 1.443%, and an 1% improvement in a partner country’s performance would help promote Vietnam's exports to this country by 0.546%

    Streptococcus agalactiae Associated with "Dark Body" Disease on Snakeskin Gourami Farmed in the Mekong Delta, Vietnam

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    Streptococcosis, due to Streptococcus agalactiae, has become a serious challenge for aquaculture around the world. Therefore, the main purpose of this work was to confirm the etiological agent that caused "dark body" disease in snakeskin gourami (Trichogaster pectoralis) cultured in the Mekong Delta, Vietnam. Infected fish displayed clinical signs, including anorexia, lethargic swimming on the water surface, corneal opacity, and hemorrhage in the base of the fin. Remarkably, abnormal black coloration on the body and serious hemorrhage at the base of the pectoral fin, and on the body were found in infected fish. In total, 75 bacterial strains were isolated from different diseased fish farms. Based on morphological and physiological characteristics, the API 20 Strep test, and 16S rRNA sequence analysis, the result illustrated that the bacterial isolates were identified as S. agalactiae. Additionally, antibiotic sensitivity testing revealed that all the S. agalactiae isolates were sensitive to amoxicillin, rifampicin, clarithromycin, erythromycin, doxycycline, cephalexin, novobiocin, and sulfamethoxazole-trimethoprim. Interestingly, S. agalactiae strains were only resistant to gentamycin in this study. Two strains, SRT41 and SRT43, carried out an experimental challenge with concentrations from 104 to 107 CFU/ml in healthy snakeskin gourami, and the LD50 values of the isolates, SRĐT41 and SRĐT43, were determined to be 2.15 × 105 and 3.59 × 103 CFU/ml, respectively, after 7 days. To our knowledge, this is the first report of S. agalactiae derived from intensively cultured snakeskin gourami in the Mekong Delta, Vietnam

    Expression of AtWRI1 and AtDGAT1 during soybean embryo development influences oil and carbohydrate metabolism

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    Soybean oil is one of the most consumed vegetable oils worldwide. Genetic improvement of its concentration in seeds has been historically pursued due to its direct association with its market value. Engineering attempts aiming to increase soybean seed oil presented different degrees of success that varied with the genetic design and the specific variety considered. Understanding the embryo’s responses to the genetic modifications introduced, is a critical step to successful approaches. In this work, the metabolic and transcriptional responses to AtWRI1 and AtDGAT1 expression in soybean seeds were evaluated. AtWRI1 is a master regulator of fatty acid (FA) biosynthesis, and AtDGAT1 encodes an enzyme catalysing the final and rate-limiting step of triacylglycerides biosynthesis. The events expressing these genes in the embryo did not show an increase in total FA content, but they responded with changes in the oil and carbohydrate composition. Transcriptomic studies revealed a down-regulation of genes putatively encoding for oil body packaging proteins, and a strong induction of genes annotated as lipases and FA biosynthesis inhibitors. Novel putative AtWRI1 targets, presenting an AW-box in the upstream region of the genes, were identified by comparison with an event that harbours only AtWRI1. Lastly, targeted metabolomics analysis showed that carbon from sugar phosphates could be used for FA competing pathways, such as starch and cell wall polysaccharides, contributing to the restriction in oil accumulation. These results allowed the identification of key cellular processes that need to be considered to break the embryo’s natural restriction to uncontrolled seed lipid increase

    Expression of \u3ci\u3eAtWRI1\u3c/i\u3e and \u3ci\u3eAtDGAT1\u3c/i\u3e during soybean embryo development influences oil and carbohydrate metabolism

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    Soybean oil is one of the most consumed vegetable oils worldwide. Genetic improvement of its concentration in seeds has been historically pursued due to its direct association with its market value. Engineering attempts aiming to increase soybean seed oil presented different degrees of success that varied with the genetic design and the specific variety considered. Understanding the embryo’s responses to the genetic modifications introduced, is a critical step to successful approaches. In this work, the metabolic and transcriptional responses to AtWRI1 and AtDGAT1 expression in soybean seeds were evaluated. AtWRI1 is a master regulator of fatty acid (FA) biosynthesis, and AtDGAT1 encodes an enzyme catalysing the final and rate-limiting step of triacylglycerides biosynthesis. The events expressing these genes in the embryo did not show an increase in total FA content, but they responded with changes in the oil and carbohydrate composition. Transcriptomic studies revealed a down-regulation of genes putatively encoding for oil body packaging proteins, and a strong induction of genes annotated as lipases and FA biosynthesis inhibitors. Novel putative AtWRI1 targets, presenting an AW-box in the upstream region of the genes, were identified by comparison with an event that harbours only AtWRI1. Lastly, targeted metabolomics analysis showed that carbon from sugar phosphates could be used for FA competing pathways, such as starch and cell wall polysaccharides, contributing to the restriction in oil accumulation. These results allowed the identification of key cellular processes that need to be considered to break the embryo’s natural restriction to uncontrolled seed lipid increase

    KHẢO SÁT ẢNH HƯỞNG CỦA CAO CHIẾT CÂY NHÀU (MORINDA CITRIFOLIA L.) ĐẾN HOẠT ĐỘNG CỦA ENZYME GLUCOSE-6-PHOSPHATASE Ở CHUỘT BỆNH TIỂU ĐƯỜNG

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    Bệnh tiểu đường (BTĐ) là bệnh do rối loạn chuyển hóa carbohydrate với đặc trưng là tăng glucose mãn tính. Tình trạng tăng đường máu mãn tính chịu chi phối của nhiều nguyên nhân khác nhau. Trong đó enzyme glucose-6-phosphatase (G-6-Pase) có chủ yếu trong gan và thận đóng vai trò quan trọng trong việc giữ cân bằng glucose trong cơ thể. Mục tiêu chính của nghiên cứu này là đánh giá khả năng hoạt động của enzyme G-6-Pase có trong gan và thận của chuột BTĐ được điều trị bằng cao chiết cây Nhàu (Morinda citrifolia L.). Chuột được gây BTĐ bằng alloxan monohydrate (AM) ở nồng độ 130 mg/kg trọng lượng chuột. Sau đó, chuột được điều trị bằng cách cho uống cao chiết Nhàu và thuốc trị bệnh tiểu đường glucofast. Sau 20 ngày, gan và thận chuột được giải phẫu để khảo sát hoạt động của enzyme G-6-Pase. Thực nghiệm đã chứng minh ngoài khả năng hạ đường huyết tương đương với thuốc glucofast, cao chiết Nhàu còn có tác dụng trong việc kiểm soát hoạt động quá mức của enzyme G-6-Pase ở những con chuột BTĐ

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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