425 research outputs found

    Optical conductivity study of screening of many-body effects in graphene interfaces

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    Theoretical studies have shown that electron-electron (e-e) and electron-hole (e-h) interactions play important roles in many observed quantum properties of graphene making this an ideal system to study many body effects. In this report we show that spectroscopic ellipsometry can enable us to measure this interactions quantitatively. We present spectroscopic data in two extreme systems of graphene on quartz (GOQ), an insulator, and graphene on copper (GOC), a metal which show that for GOQ, both e-e and e-h interactions dominate while for GOC e-h interactions are screened. The data further enables the estimation of the strength of the many body interaction through the effective fine structure constant, αg\alpha_{g}^{*}. The αg\alpha_{g}^{*} for GOQ indicates a strong correlation with an almost energy independent value of about 1.37. In contrast, αg\alpha_{g}^{*} value of GOC is photon energy dependent, is almost two orders of magnitude lower at low energies indicating very weak correlation.Comment: Main Article (4 pages, 4 figures); Supporting Online Material (12 pages, 9 figures

    Sulphate behaviour from dissolution of gypsum in organic acids

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    The solubility of gypsum in organic acids namely acetic, oxalic, tartaric and succinic acids at low temperature (3

    Prevalence of Mycoplasma bovis Infection in calves and dairy cows in Western Australia

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    Mycoplasma bovis (M. bovis) can cause a multitude of diseases in cattle, with detrimental effects on the farm economy and the welfare of both adult and young cattle. The objective of this study was to determine the prevalence of M. bovis in adult cows and calves in the south-west region of Western Australia. A cross-sectional study was conducted on 29 dairy farms with 699 apparently healthy adult lactating cows and 495 young calves during 2019–2020. Nasal swabs and blood samples collected from the animals and bulk tank milk (BTM) samples were assessed for M. bovis-specific proteins and antibodies by using polymerase chain reaction (PCR) and Mycoplasma immunogenic lipase A- Enzyme-Linked Immune Sorbent Assay (MilA ELISA). A seroprevalence of 42.5% (95% CI: 38.9–46.2) and 61% (95% CI: 56.6–65.2) was found in adult lactating cows and calves, respectively. The herd-level seroprevalence of M. bovis ranged from 4% (95% CI: 07–19.5) to 92% (95% CI: 75.0–97.8) in adult lactating cows and 25% (95% CI: 10.2–49.5) to 87% (95% CI: 67.9–95.5) for calves in these farms. None of the BTM and nasal swab samples were positive for M. bovis, indicating an absence of any current active infections on the farms. The female calves and pure Holstein–Friesian animals are twice as likely to be seropositive for M. bovis compared to male calves (OR 2.4; 95% CI: 1.7–3.5) and Holstein–Friesian crossbred calves (OR 2.4; 95% CI: 1.7–3.5). The high seroprevalence in both adult and young cattle in the southwest dairy farms of Western Australia warrants more effective farm biosecurity measures and further evaluation of the current prevention and management measures practiced on the farms

    Optimization of process parameters for improved production of bioactive metabolite by a novel endophytic fungus Fusarium sp. DF2 isolated from Taxus wallichiana of North East India

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    An endophytic fungus having antifungal and antibacterial properties was isolated from Taxus wallichiana of Arunachal Pradesh, India. On the basis of morphological and molecular characteristics, the fungus was identified as Fusarium sp. and designated as DF2. The fungus was optimized for growth and maximum production of the antimicrobial agent. Media with 5% leaf extract (w/v) supplemented with 0.1% dextrose as carbon and yeast extract as nitrogen source favored the growth with temperature optimum 25 ± 2°C and pH 6. Incubation period of 10 days was observed optimum for growth and production of antimicrobial agent. Phenylalanine and dextrose enriched basal medium promoted the antimicrobial agent production, whereas methionine amended in combination with glucose promoted higher biomass accumulation. The TLC purified active compound with UV λ-max 270 nm in ethyl acetate has got the lowest minimum inhibitory concentration (MIC) against Bacillus subtilis, Staphylococcus aureus and Escherichia coli and highest against Pseudomonas aeruginosa

    Cloning and heterologous expression of a gene encoding lycopene-epsilon-cyclase, a precursor of lutein in tea (Camellia sinensis var assamica)

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    This report describes the cloning and expression of a gene lycopene epsilon cyclase, (LCYE) from Camellia sinensis var assamica which is a precursor of the carotenoid lutein in tea. The 1982 bp cDNA sequence with 1599 bp open reading frame of LCYE was identified from an SSH library constructed for quality trait in tea. 5’ and 3’ RACE (rapid-amplification of cDNA ends) was done to clone the full length cDNA of LCYE. Homology studies showed that the deduced amino acid sequence of LCYE gene had the highest sequence identity of up to 84% with Vitis vinefera. The cloned gene was successfully expressed in a PET based Escherichia coli expression system. The size of the expressed protein was 59615 Daltons. A suppression subtractive library was constructed using a quality clone H3111 (tester) and a garden series clone T3E3 (driver).Key words: Carotenoid, RACE, heterologous expression, lutein, tea

    Effect of Freezing Rate on Quality of Cryopreserved Goat Spermatozoa Using a Programmable Freezer

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    Abstract: A total of 45 ejaculates from nine Beetal bucks collected by artificial vagina, washed and extended i

    Next Generation Application-Aware Flow Monitoring

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    Deep packet inspection (DPI) and IP flow monitoring are frequently used network monitoring approaches. Although the DPI provides application visibility, detailed examination of every packet is computationally intensive. The IP flow monitoring achieves high performance by processing only packet headers, but provides less details about the traffic itself. Application-aware flow monitoring is proposed as an attempt to combine DPI accuracy and IP flow monitoring performance. However, the impacts, benefits and disadvantages of application flow monitoring have not been studied in detail yet. The work proposed in this paper attempts to rectify this lack of research. We also propose a next generation flow measurement for application monitoring. The flows will represent events within the application protocol, e.g., web page download, instead of packet stream. Finally, we will investigate the performance of different approaches to application classification and application parsing with a computational complexity in mind.Často používané metody monitorování sítě jsou hloubková inspekce paketů (DPI) a monitorování síťových IP toků. Přestože DPI poskytuje formace z aplikační vrstvy, podrobné zkoumání každého paketu je výpočetně náročné. Monitorování pomocí IP síťových toků dosahuje vysokého výkonu, protože zpracovává pouze záhlaví paketů, ale také poskytuje méně informací o provozu samotném. Měření aplikačních síťových toků bylo navrženo jako pokus zkombinovat přesnost DPI a výkon IP síťových toků. Dopady, výhody a nevýhody aplikačních síťových toků zatím ale nebyly dostatečně prostudovány. Práce navrhovaná v tomto článku se snaží napravit tento nedostatek výzkumu. Navíc také navrhujeme další generaci měření síťových toků. Tyto toky budou místo sekvence paketů reprezentovat události v aplikačních protokolech, například stažení webové stránky. Budeme se také zabývat výkonem a výpočetní složitostí různých přístupů ke klasifikaci provozu a zpracování aplikačních protokolů
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