65 research outputs found

    Photoelectric observations of the long-period eclipsing binaries at Yonsei University Observatory

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    A long term project (ten-years; 1982-92) for the photoelectric observation in the UBV passbands of selected eclipsing binaries with P 10 days has initiated at Yonsei University Observatory using 40-cm and 61-cm reflectors. The instrumentation used and the observation techniques and the reduction procedures applied to this investigation are described

    Methods of asymptotic analysis in cavity quantum electrodynamics

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    The energy-level shift of a ground-state atom in front of a nondispersive dielectric half-space is calculated by quantizing the electric field by means of a normal-mode expansion and applying second-order perturbation theory to the electric-dipole Hamiltonian muE. It is shown that the contributions to this shift coming from traveling and from evanescent waves can be combined into a single expression which lends itself readily to asymptotic analysis for large atom-surface separations, while in the opposite asymptotic regime when the atom is close to the surface the combined expression is less convenient. Employing a Greens-function formalism instead of the normal-mode expansion leads directly to the combined formula, and in that case it is advantageous to be able to apply the same transformation backwards and split the energy shift into a sum of distinct contributions corresponding to different physical processes. The analysis serves to shed light on common sources of error in the literature and paves the way for the study of more complicated models in cavity quantum electrodynamics

    Information Invariance and Quantum Probabilities

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    We consider probabilistic theories in which the most elementary system, a two-dimensional system, contains one bit of information. The bit is assumed to be contained in any complete set of mutually complementary measurements. The requirement of invariance of the information under a continuous change of the set of mutually complementary measurements uniquely singles out a measure of information, which is quadratic in probabilities. The assumption which gives the same scaling of the number of degrees of freedom with the dimension as in quantum theory follows essentially from the assumption that all physical states of a higher dimensional system are those and only those from which one can post-select physical states of two-dimensional systems. The requirement that no more than one bit of information (as quantified by the quadratic measure) is contained in all possible post-selected two-dimensional systems is equivalent to the positivity of density operator in quantum theory.Comment: 8 pages, 1 figure. This article is dedicated to Pekka Lahti on the occasion of his 60th birthday. Found. Phys. (2009

    The many possible climates from the Paris Agreement’s aim of 1.5 °C warming

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    The United Nations’ Paris Agreement includes the aim of pursuing efforts to limit global warming to only 1.5 °C above pre-industrial levels. However, it is not clear what the resulting climate would look like across the globe and over time. Here we show that trajectories towards a ‘1.5 °C warmer world’ may result in vastly different outcomes at regional scales, owing to variations in the pace and location of climate change and their interactions with society’s mitigation, adaptation and vulnerabilities to climate change. Pursuing policies that are considered to be consistent with the 1.5 °C aim will not completely remove the risk of global temperatures being much higher or of some regional extremes reaching dangerous levels for ecosystems and societies over the coming decades

    Replacement of Marine Fish Oil with de novo Omega-3 Oils from Transgenic Camelina sativa in Feeds for Gilthead Sea Bream (Sparus aurata L.)

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    Omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA) are essential components of the diet of all vertebrates and. The major dietary source of n-3 LC-PUFA for humans has been fish and seafood but, paradoxically, farmed fish are also reliant on marine fisheries for fish meal and fish oil (FO), traditionally major ingredients of aquafeeds. Currently, the only sustainable alternatives to FO are vegetable oils, which are rich in C18 PUFA, but devoid of the eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) abundant in FO. Two new n-3 LC-PUFA sources obtained from genetically modified (GM) Camelina sativa containing either EPA alone (ECO) or EPA and DHA (DCO) were compared to FO and wild-type camelina oil (WCO) in juvenile sea bream. Neither ECO nor DCO had any detrimental effects on fish performance, although final weight of ECO-fed fish (117 g) was slightly lower than that of FO- and DCO-fed fish (130 and 127 g, respectively). Inclusion of the GM-derived oils enhanced the n-3 LC-PUFA content in fish tissues compared to WCO, although limited biosynthesis was observed indicating accumulation of dietary fatty acids. The expression of genes involved in several lipid metabolic processes, as well as fish health and immune response, in both liver and anterior intestine were altered in fish fed the GM-derived oils. This showed a similar pattern to that observed in WCO-fed fish reflecting the hybrid fatty acid profile of the new oils. Overall the data indicated that the GM-derived oils could be suitable alternatives to dietary FO in sea bream

    СПЕКТРЫ DLTS КРЕМНИЕВЫХ ДИОДОВ С p+—n–ПЕРЕХОДОМ, ОБЛУЧЕННЫХ ВЫСОКОЭНЕРГЕТИЧЕСКИМИ ИОНАМИ КРИПТОНА

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    p+-n-Diodes have been studied. The diodes were manufactured on wafers (thickness 460 μm, (111) plane) of uniformly phosphorus doped float–zone–grown single–crystal silicon. The resistivity of silicon was 90 Ohm · cm and the phosphorus concentration was 5 · 1013 cm–3. The diodes were irradiated with 250 MeV krypton ions. The irradiation fluence was 108 cm–2. Deep–level transient spectroscopy (DLTS) was used to examine the defects induced by high energy krypton ion implantation. The DLTS spectra were recorded at a frequency of 1 MHz in the 78—290 K temperature range. The capacity–voltage characteristics have been measured at a reverse bias voltage from 0 to –19 V at a frequency of 1 MHz. We show that the main irradiation–induced defects are A–centers and divacancies. The behavior of DLTS spectra in the 150—260 K temperature range depends essentially on the emission voltage Ue. The variation of Ue allows us to separate the contributions of different defects into the DLTS spectrum in the 150—260 K temperature range. We show that, in addition to A–centers and divacancies, irradiation produces multivacancy complexes with the energy level Et = Ec – (0.5 ± 0.02) eV and an electron capture cross section of ~4 · 10–13 cm2.Исследованы p+—n-диоды. Диоды изготовлены на пластинах однородно легированного фосфором монокристаллического кремния (толщина 460 мкм, плоскость (111)), выращенного методом бестигельной зонной плавки. Удельное сопротивление кремния — 90 Ом × см, концентрация фосфора — 5 × 1013 см−3. Диоды подвергнуты облучению ионами криптона с энергией 250 МэВ. Флюенс облучения — 108 см−2. Радиационные дефекты, вводимые высокоэнергетической имплантацией ионов криптона, исследованы с помощью нестационарной спектроскопии глубоких уровней (DLTS — Deep−level transient spectroscopy). Спектры DLTS регистрировали на частоте 1 МГц в интервале температур 78—290 К. Вольт-фарадные характеристики измерены при напряжении обратного смещения от 0 до – 19 В на частоте 1 МГц. Показано, что основными радиационными дефектами являются А−центры и дивакансии. Установлено, что вид спектров DLTS в интервале температур 150—260 K существенно зависит от напряжения эмиссии Ue. Варьирование Ue в ходе эксперимента позволило разделить вклады от различных дефектов в спектр DLTS в интервале температур 150—260 К. Показано, что, помимо А−центров и дивакансий, при облучении формируются многовакансионные комплексы с энергетическим уровнем Et = Ec -(0,50 ± 0,02) эВ и сечением захвата электронов ~ 4 × 10−13 см2

    Plant cell culture technology in the cosmetics and food industries : current state and future trends

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    The production of drugs, cosmetics, and food which are derived from plant cell and tissue cultures has a long tradition. The emerging trend of manufacturing cosmetics and food products in a natural and sustainable manner has brought a new wave in plant cell culture technology over the past 10 years. More than 50 products based on extracts from plant cell cultures have made their way into the cosmetics industry during this time, whereby the majority is produced with plant cell suspension cultures. In addition, the first plant cell culture-based food supplement ingredients, such as Echigena Plus and Teoside 10, are now produced at production scale. In this mini review, we discuss the reasons for and the characteristics as well as the challenges of plant cell culture-based productions for the cosmetics and food industries. It focuses on the current state of the art in this field. In addition, two examples of the latest developments in plant cell culture-based food production are presented, that is, superfood which boosts health and food that can be produced in the lab or at home
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