37 research outputs found

    A new stability results for the backward heat equation

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    In this paper, we regularize the nonlinear inverse time heat problem in the unbounded region by Fourier method. Some new convergence rates are obtained. Meanwhile, some quite sharp error estimates between the approximate solution and exact solution are provided. Especially, the optimal convergence of the approximate solution at t = 0 is also proved. This work extends to many earlier results in (f2,f3, hao1,Quan,tau1, tau2, Trong3,x1).Comment: 13 page

    Combining content and social features in a deep learning approach to Vietnamese email prioritization

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    The email overload problem has been discussed in numerous email-related studies. One of the possible solutions to this problem is email prioritization, which is the act of automatically predicting the importance levels of received emails and sorting the user’s inbox accordingly. Several learning-based methods have been proposed to address the email prioritization problem using content features as well as social features. Although these methods have laid the foundation works in this field of study, the reported performance is far from being practical. Recent works on deep neural networks have achieved good results in various tasks. In this paper, the authors propose a novel email prioritization model which incorporates several deep learning techniques and uses a combination of both content features and social features from email data. This method targets Vietnamese emails and is tested against a self-built Vietnamese email corpus. Conducted experiments explored the effects of different model configurations and compared the effectiveness of the new method to that of a previous work

    Ice formation in the Arctic during summer: false-bottoms

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    The only source of ice formation in the Arctic during summer is a layer of ice called false-bottoms between an under-ice melt pond and the underlying ocean. Of interest is to give a mathematical model in order to determine the simultaneous growth and ablation of false-bottoms, which is governed by both of heat fluxes and salt fluxes. In one dimension, this problem may be considered mathematically as a two-phase Stefan problem with two free boundaries. Our main result is to prove the existence and uniqueness of the solution from the initial condition.Comment: 22 page

    Light Absorption and Luminescence Properties of the Blend Poly(N-vinylcarbazole)/Poly(N-hexylthiophene)

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    We have investigated the enhancement absorption light and luminescence properties of the blend conducting polymers using poly(N-vinylcarbazole) and poly(N-hexylthiophene). The optimized material showed a broad absorption in the region of ultra violet to near infra-red and the better of luminescence ability than the pristine conducting polymers. The remarkable improvements in photoluminescences of the blends provide useful information to the application of this material in fabrication of optical – electronic devices.

    The Role of Serial NT-ProBNP Level in Prognosis and Follow-Up Treatment of Acute Heart Failure after Coronary Artery Bypass Graft Surgery

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    BACKGROUND: After coronary artery bypass graft (CABG) surgery, heart failure is still major problem. The valuable marker for it is needed. AIM: Evaluating the role of serial NT-proBNP level in prognosis and follow-up treatment of acute heart failure after CABG surgery. METHODS: The prospective, analytic study evaluated 107 patients undergoing CABG surgery at Ho Chi Minh Heart Institute from October 2012 to June 2014. Collecting data was done at pre- and post-operative days with measuring NT-proBNP levels on the day before operation, 2 hours after surgery, every next 24 h until the 5th day, and in case of acute heart failure occurred after surgery. RESULTS: On the first postoperative day (POD1), the NT-proBNP level demonstrated significant value for AHF with the cut-off point = 817.8 pg/mL and AUC = 0.806. On the second and third postoperative day, the AUC value of NT- was 0.753 and 0.751. It was statistically significant in acute heart failure group almost at POD 1 and POD 2 when analyzed by the doses of dobutamine, noradrenaline, and adrenaline (both low doses and normal doses). CONCLUSION: Serial measurement of NT-proBNP level provides useful prognostic and follow-up treatment information in acute heart failure after CABG surgery

    Functional-Antioxidant Food

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    Nowadays, people face many different dangers, such as stress, unsafety food, and environmental pollution, but not everyone suffers. Meanwhile, free radicals are the biggest threat for humans because they lead to over 80 different diseases composed of aging. Free radicals can only be eliminated or minimized with antioxidant foods or antioxidants. The chapter on the functional-antioxidant food presents the antioxidant functional food concept, the classification, the structure, and the extraction process of antioxidant ingredients. Various antioxidant substances such as protein (collagen), polysaccharides (fucoidans, alginates, glucosamines, inulins, laminarins, ulvans, and pectins), and secondary metabolites (polyphenols (phlorotannins, lignins, polyphenols), alkaloids, and flavonoids) also present. The production technology, the mechanism, the opportunity, and the challenge of antioxidants functional food also present in the current chapter. The current chapter also gives the production process of functional-antioxidant food composed of the capsule, the tablet, tube, the pills, the powder, and the effervescent tablet

    NGHIÊN CỨU THÀNH PHẦN VÀ HÀM LƯỢNG CÁC LỚP CHẤT LIPID, PHOSPHOLIPID, AXIT BÉO, VÀ PHOSPHATIDYLCHOLINE LOÀI SAN HÔ MỀM CAPNELLA SP.

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    The total lipid content of the soft coral Capnella sp. contained 1.44 ± 0.10% of the fresh weight. In the fatty acid content, the tetracosapolyenoic fatty acids 24:5n-6 and 24:6n-3, which were the typical markers for the soft corals (the eight compartment coral), and the fatty acids that marked for symbiotic microorganism including 18:5n-3, 18:2n-6, 18:3n-6, 18:4n-3, 20:4n-3 were presented. The result of the lipid composition analysis showed that the total lipid contained polar lipid, sterol, free fatty acid, triacylglycerol, monoalkyldiacylglycerol, hydrocarbon and wax. Of these, the polar lipid displayed the highest content with 21.14 ± 1.17% of the total lipid. The phospholipid composition of the soft coral Capnella sp. contained the characteristic phospholipid subclasses of the animals of the phylum Cnidaria, including phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, and ceramide aminoethylphosphonate (phosphonolipid, CAEP). Of these, phosphatidylcholine exhibited the highest content with 35.53 ± 1.46% of the total phospholipid. This is the first time that the content and composition of the molecular types of the phosphatidylcholine from a Vietnamese soft coral species have been investigated and reported. By using modern mass spectrometry IT TOF LC-MS, the presence of 13 molecular types have been precisely identified, which PC 18:0e/20:4 and PC 16:0e/20:4 were the two ingredients displaying the highest content.Hàm lượng lipid tổng của mẫu san hô mềm Capnella sp. chiếm 1,44 ± 0,10% so với trọng lượng mẫu tươi. Trong thành phần axit béo có mặt các axit béo tetracosapolyenoic 24:5n-6 và 24:6n-3 là axit béo đánh dấu điển hình cho san hô mềm (san hô tám ngăn) và các axit béo đánh dấu cho vi sinh vật cộng sinh như 18:5n-3, 18:2n-6, 18:3n-6, 18:4n-3, 20:4n-3. Kết quả phân tích lớp chất lipid cho thấy trong lipid tổng có mặt các lớp chất lipid chính là lipid phân cực, sterol, axit béo tự do, triacylglycerol, monoalkyldiacylglycerol, hydrocacbon và sáp, trong đó lipid phân cực chiếm hàm lượng cao nhất (21,14 ± 1,17% hàm lượng lipid tổng). Thành phần phospholipid của san hô mềm Capnella sp. có mặt các phân lớp phospholipid đặc trưng của động vật ngành Cnidarian là phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, phosphonolipid là ceramide aminoethylphosphonate, trong đó phosphatidylcholine chiếm hàm lượng cao nhất (35,53 ± 1,46% tổng phospholipid). Đây là lần đầu tiên ở Việt Nam, thành phần và hàm lượng các dạng phân tử trong lớp chất phosphatidylcholine từ loài san hô mềm của Việt Nam được nghiên cứu và công bố, kết quả đã xác định được sự có mặt của 13 dạng phân tử bằng phương pháp phổ khối hiện đại LC-MS IT TOF với độ chính xác cao. Hai dạng phân tử chiếm hàm lượng cao nhất là PC 18:0e/20:4 và PC 16:0e/20:4

    SHREC’20 Track:Retrieval of digital surfaces with similar geometric reliefs

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    International audienceThis paper presents the methods that have participated in the SHREC'20 contest on retrieval of surface patches with similar geometric reliefs and 1 the analysis of their performance over the benchmark created for this challenge. The goal of the context is to verify the possibility of retrieving 3D models only based on the reliefs that are present on their surface and to compare methods that are suitable for this task. This problem is related to many real world applications, such as the classification of cultural heritage goods or the analysis of different materials. To address this challenge, it is necessary to characterize the local "geometric pattern" information, possibly forgetting model size and bending. Seven groups participated in this contest and twenty runs were submitted for evaluation. The performances of the methods reveal that good results are achieved with a number of techniques that use different approaches

    Global estimates on the number of people blind or visually impaired by cataract: a meta-analysis from 2000 to 2020

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    Background: To estimate global and regional trends from 2000 to 2020 of the number of persons visually impaired by cataract and their proportion of the total number of vision-impaired individuals. Methods: A systematic review and meta-analysis of published population studies and gray literature from 2000 to 2020 was carried out to estimate global and regional trends. We developed prevalence estimates based on modeled distance visual impairment and blindness due to cataract, producing location-, year-, age-, and sex-specific estimates of moderate to severe vision impairment (MSVI presenting visual acuity &lt;6/18, ≥3/60) and blindness (presenting visual acuity &lt;3/60). Estimates are age-standardized using the GBD standard population. Results: In 2020, among overall (all ages) 43.3 million blind and 295 million with MSVI, 17.0 million (39.6%) people were blind and 83.5 million (28.3%) had MSVI due to cataract blind 60% female, MSVI 59% female. From 1990 to 2020, the count of persons blind (MSVI) due to cataract increased by 29.7%(93.1%) whereas the age-standardized global prevalence of cataract-related blindness improved by −27.5% and MSVI increased by 7.2%. The contribution of cataract to the age-standardized prevalence of blindness exceeded the global figure only in South Asia (62.9%) and Southeast Asia and Oceania (47.9%). Conclusions: The number of people blind and with MSVI due to cataract has risen over the past 30 years, despite a decrease in the age-standardized prevalence of cataract. This indicates that cataract treatment programs have been beneficial, but population growth and aging have outpaced their impact. Growing numbers of cataract blind indicate that more, better-directed, resources are needed to increase global capacity for cataract surgery.</p
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