23 research outputs found

    Evolutionary tracks for Betelgeuse

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    We have constructed a series of non-rotating quasi-hydrostatic evolutionary models for the M2 Iab supergiant Betelgeuse (α Orionis\alpha~Orionis). Our models are constrained by multiple observed values for the temperature, luminosity, surface composition and mass loss for this star, along with the parallax distance and high resolution imagery that determines its radius. We have then applied our best-fit models to analyze the observed variations in surface luminosity and the size of detected surface bright spots as the result of up-flowing convective material from regions of high temperature in the surface convective zone. We also attempt to explain the intermittently observed periodic variability in a simple radial linear adiabatic pulsation model. Based upon the best fit to all observed data, we suggest a best progenitor mass estimate of 203+5M 20 ^{+5}_{-3} M_\odot and a current age from the start of the zero-age main sequence of 8.08.58.0 - 8.5 Myr based upon the observed ejected mass while on the giant branch.Comment: 27 pages, 11 figures, Revised per referee suggestions, Accepted for publication in the Astrophysical Journa

    The Impacts of Distance between Phosphor Layers on Optical Properties of Triple-Layer Phosphor Structure

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    One of the crucial goals often thought of in connection with remote phosphors is to make the emitted photon larger than other structures. However, the two biggest hurdles that make achieving the goals more challenging are color uniformity and Color Rendering Index (CRI). This is the reason why people have started to pay more attention to these issues in recent research papers. Thus, this study will present the idea of controlling the distance between phosphor layers to control the optical parameters of White light LED (WLED). Based on the Mie scattering theory, which is about absorption and scattering of plane electromagnetic waves by uniform isotropic particles of the simplest form (sphere, infinite cylinder) which are in a uniform and isotropic dielectric infinite medium, the results of the study are confirmed to be completely accurate and reliable. Specifically, when d = 0.64 mm, the flux can increase to 9.7% compared to the original. Similarly, when d = 0.84 mm, the color uniformity can be double better meanwhile the CRI value is kept intact. Once fully calculated and substantiated, the paper will provide comparable results in practice for the production of higher quality WLED

    ẢNH HƯỞNG CỦA VITAMIN E BỔ SUNG VÀO THỨC ĂN ĐẾN HIỆU QUẢ SINH SẢN, CHẤT LƯỢNG TRỨNG VÀ ẤU TRÙNG CÁ KHOANG CỔ NEMO (Amphiprion ocellaris (CUVIER, 1830))

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    This study was carried out to determine the effects of vitamin E (a-tocopherol) in five levels (0, 125, 250, 375 and 500 mg vitamin E/kg feed) in broodfish diets on reproductive, egg and larval quality parameters of clownfish (Amphirion ocellaris). Each treatment was repeated in triplicate and the supplemental feeding trial was arranged for 13 months. The result showed that there were no significant differences in re-maturation and spawning periods, spawning frequency, fecundity, egg diameter and larval size of Nemo fish observed between the treatments. However, diets supplemented with vitamin E positively influenced the rate of egg loss, hatching rate of egg and survival rate of the 3 days post hatch. The overall result of this experiment indicated that the optimum vitamin E requirement of clownfish for reproductive performance was 375 mg vitamin E/kg feed.Thí nghiệm được thực hiện nhằm xác định ảnh hưởng của vitamin E (0, 125, 250, 375 và 500 mg/kg thức ăn) được bổ sung trong thức ăn cá bố mẹ đến các chỉ số sinh sản, chất lượng trứng và ấu trùng cá khoang cổ Nemo (Amphiprion ocellaris). Mỗi nghiệm thức được lặp lại 3 lần và thí nghiệm được tiến hành trong 13 tháng. Kết quả đã cho thấy thời gian tái thành thục và sinh sản, tần suất sinh sản, sức sinh sản thực tế, đường kính trứng và kích thước ấu trùng không bị ảnh hưởng bởi chế độ ăn bổ sung vitamin E ở các mức khác nhau. Tuy nhiên, chế độ ăn có bổ sung vitamin E đã ảnh hưởng tích cực đến tỷ lệ hao hụt của trứng, tỷ lệ trứng nở và tỷ lệ sống của ấu trùng 3 ngày tuổi. Kết quả nghiên cứu chỉ ra rằng nhu cầu vitamin E tối ưu của cá khoang cổ Nemo đạt được hiệu quả sinh sản là 375 mg vitamin E/kg thức ăn

    Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

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    Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

    Identification and quantification of beta-casomorphin peptides naturally yielded in raw milk by liquid chromatography-tandem mass spectrometry

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    Beta-casomorphin peptides including beta-casomorphin 5 (β-CM5) and beta-casomorphin 7 (β-CM7) in raw cow milk were analyzed using a liquid chromatography-tandem mass spectrometry (LC-MS/MS). Milk samples were acidified with HCl followed by centrifuged and cleaned-up using solid-phase extraction (SPE). The eluents were evaporated to dryness and subsequently reconstituted with methanol. Limits of detection (LOD) were 0.32 ng/g for β-CM5 and 0.24 ng/g for β-CM7 and limits of quantification (LOQ) were 1.06 ng/g and 0.69 ng/g for β-CM5 and β-CM7, respectively. Recoveries ranged from 89.7% to 99.4% for β-CM5 and from 96.3% to 98.9% for β-CM7. Intra-day precision was ranged between 7.3% and 22.7% for β-CM5; and 4.5% and 7.3% for β-CM7, meanwhile inter-day precision resulted 7.3%–16.5% for β-CM5 and 9.3%–12.8% for β-CM7. The concentration of β-CM5/7 was analyzed in different milk samples. β-CM7 was detected in 21 out of 30 samples and ranged from 0.76 to 8.41 ng/g milk, while β-CM5 was unequivocally identified in 3 samples, its concentration was 0.4–0.64 ng/g. This is the first report to describe the natural occurrence of β-CM5/7 in raw milk using LC-MS/MS. The present study provides evidence of β-CMs, especially β-CM7 that can be released in raw milk from different breeds

    Improving SERS Sensing Efficiency and Catalytic Reduction Activity in Multifunctional Ternary Ag-TiO2-GO Nanostructures: Roles of Electron Transfer Process on Performance Enhancement

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    Multifunctional nanocomposites have received great attention for years; electron transfer (ET) is considered as an explanatory mechanism for enhancement of performance of these nanostructures. The existence of this ET process has been proved in many studies using either experimental or computational approaches. In this study, a ternary nanocomposite system of Ag/TiO2/GO was prepared to evaluate the performance enhancement in two experimental models: a physical model (i.e., surface-enhanced Raman scattering (SERS) sensor) and a chemical one (i.e., catalytic reduction reaction). The metal/semiconductor heterojunction between Ag and TiO2, as well as Ti-O-C bonds, has allowed plasmonic hot electrons to be transferred in the internal structure of the material. An investigation on the role of Ag content on the SERS sensing and catalytic reduction efficiency of Ag/TiO2/GO was performed in both models. Interestingly, they all resulted in the same optimal Ag content of 50 wt%. It was then further discussed to provide a convincing evidence for the plasmon-induced electron transfer phenomena in the Ag/TiO2/GO nanostructure. These findings also suggest a pathway to design and develop high-performance, cost-effective, facile-preparation, and eco-friendly multifunctional nanostructures for detecting and removing contaminants in environment
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