1,118 research outputs found
Electronic structure and spectroscopy of O2 and O2+
We carried out a comprehensive SCF MRD--CI ab initio study of the
electronic
structure of O and O. Potential energy curves (PECs) of
about 150
electronic states of O and
about
100 of O, as well as a number of
states of
O were computed. The cc--pVQZ basis set augmented with diffuse
functions was employed. Spectroscopic parameters
( , ,
IP, etc.) are reported.
A preliminary sample of the results will be presented. The electronic absorption
spectrum of O has proved difficult to analyze/interpret
due to the unusually large number of electronic states which arise
from
the peculiar open--shell structure of both the oxygen atomic fragments and the
O molecule. For instance, there are 62 valence molecular electronic
states which
correlate to the six lowest dissociation limits resulting from
the three valence O atom fragment states (P, D, S).
In addition, there are several Rydberg series
converging to the X ground ionic state and to the lowest
two excited states of the cation, a and A.
Furthermore, a number of interactions of various types among several electronic states result in rovibronic perturbations
which manifest themselves, e.g., as irregular vibronic structure,
hence severely complicating the
assignment of the absorption features and the analysis and
interpretation of the spectrum.
An overview of the electronic states and spectroscopy of O will be presented.
A chief motivation of this study of O was
to try to provide a theoretical insight on the nature,
energetic position, shape, and dissociation asymptotes,
of electronic states located in the 4 eV energy region
encompassed between the O ground state X (IP eV)
and the first excited state of the cation a
(IP eV).
This in order to aid in the interpretation of experimental data
related to the mechanism(s) of the neutral dissociation of the O
(Rydberg) superexcited states,
which competes with autoionization.
We are currently striving to compute PECs of relatively highly
excited states of O located in the 12--16 eV energy region which might
help to visualize possible pathways for the
neutral XUV photodissociation of the I, I and I
superexcited states of O leading to the O(P) + O(S, S) dissociation limits.Ope
About ecology around industrial areas of Мariupol
Содержание кислорода в атмосферном воздухе городов, а также в жилых, офисных и производственных
помещениях является важнейшим фактором самочувствия и здоровья горожан. При высокой температуре и высокой абсолютной влажности приземного воздуха, содержание кислорода в атмосферном воздухе минимально, и люди могут испытывать признаки гипоксии. В промышленных южных городах, к которым относится г. Мариуполь (Украина), существуют дополнительные факторы, затрудняющие дыхание человека: более высокая (относительно окружающей город территории) температура воздуха и загрязненность атмосферы, в т. ч. угарным газом и взвешенными частицами. Это приводит в условиях аномальной жары и промышленных выбросов к повышению заболеваемости и смертности городского населения. Точные измерения парциального давления и парциальной плотности кислорода требуют специального оборудования и методик, поскольку процентное содержание кислорода в атмосферном воздухе достаточно
велико, а его изменения относительно малы. Большинство современных приборов, используемых городскими службами мониторинга атмосферы, ориентированы на измерение существенных отклонений содержания кислорода от нормы. Службы мониторинга состава воздуха обычно не измеряют плотность кислорода, по-видимому, из-за неявного предположения ничтожного влияния изменения метеоусловий на его содержание. Кроме того, измерение малых изменений содержания кислорода в приземном слое воздуха является достаточно сложной технической задачей. В работе представлена попытка аналитического определения распределения концентраций кислорода в приземных слоях атмосферы
вокруг мест стока кислорода из атмосферы на металлургических предприятиях г. Мариуполя, приведена аналитическая модель стока кислорода из приземного слоя на основе теории «обратной струи» в одномерной постановке. Получены соответствующие изолинии концентраций на различных расстояниях от мест стока кислорода. При этом концентрация кислорода снижается обратно пропорционально расстоянию от стока, что позволяет достаточно просто оценивать распределение концентраций в приземном слое атмосферы вокруг металлургических предприятий при известных координатах мест его стока в безветренную погоду. Проанализирована пространственная изменчивость и эпизоды аномального содержания кислорода в приземном воздухе в контексте их возможного влияния на самочувствие людей.The oxygen content in the atmospheric air of cities, as well as in residential, office and industrial premises is the most important factor in the health and well-being of citizens. With high temperature and high absolute humidity of the surface air, the oxygen content in ambient air is minimal, and people may experience signs of hypoxia. In the industrial southern cities to which the city of Mariupol (Ukraine) belongs, there are additional factors that impede human breathing: higher (relative to the territory surrounding the city) air temperature and pollution of the atmosphere, including carbon monoxide and suspended particles. This results in conditions of abnormal heat and industrial emissions to an increase in the morbidity and mortality of the urban population. Accurate measurements of partial pressure and partial density of oxygen require special equipment and techniques, since the percentage of oxygen in ambient air is large enough, and its changes are relatively small. Most modern instruments used by urban
atmospheric monitoring services are focused on measuring significant deviations of oxygen content from the norm. Air quality monitoring services do not usually measure the density of oxygen, apparently due to the implicit assumption of the negligible effect of changes in weather conditions on its content. In addition, the measurement of small changes in the oxygen content in the surface air is a rather complicated technical task. The paper presents an attempt to analytically determine the distribution of oxygen concentrations in the surface layers of the atmosphere around the places of oxygen runoff from the atmosphere at metallurgical enterprises of Mariupol, provides an analytical model based on the theory of "reverse flow" in a one-dimensional formulation of oxygen flow from the surface layer. The corresponding concentration contour lines were obtained at various distances from the
oxygen sink sites. At the same time, the oxygen concentration decreases inversely with the distance from the drain, which makes it quite easy to estimate the distribution of concentrations in the surface layer of the atmosphere around the metallurgical enterprises at known coordinates of its drain points in calm weather. The spatial variability and episodes of anomalous oxygen content in the surface air are analyzed in the context of their possible effect on people's well-being
Differential effects of selective inhibitors targeting the PI3K/AKT/mTOR pathway in acute lymphoblastic leukemia
Purpose: Aberrant PI3K/AKT/mTOR signaling has been linked to oncogenesis and therapy resistance in various malignancies including leukemias. In Philadelphia chromosome (Ph) positive leukemias, activation of PI3K by dysregulated BCR-ABL tyrosine kinase (TK) contributes to the pathogenesis and development of resistance to ABL-TK inhibitors (TKI). The PI3K pathway thus is an attractive therapeutic target in BCR-ABL positive leukemias, but its role in BCR-ABL negative ALL is conjectural. Moreover, the functional contribution of individual components of the PI3K pathway in ALL has not been established.
Experimental design: We compared the activity of the ATP-competitive pan-PI3K inhibitor NVP-BKM120, the allosteric mTORC1 inhibitor RAD001, the ATP-competitive dual PI3K/mTORC1/C2 inhibitors NVP-BEZ235 and NVP-BGT226 and the combined mTORC1 and mTORC2 inhibitors Torin 1, PP242 and KU-0063794 using long-term cultures of ALL cells (ALL-LTC) from patients with B-precursor ALL that expressed the BCR-ABL or TEL-ABL oncoproteins or were BCR-ABL negative.
Results: Dual PI3K/mTOR inhibitors profoundly inhibited growth and survival of ALL cells irrespective of their genetic subtype and their responsiveness to ABL-TKI. Combined suppression of PI3K, mTORC1 and mTORC2 displayed greater antileukemic activity than selective inhibitors of PI3K, mTORC1 or mTORC1 and mTORC2.
Conclusions: Inhibition of the PI3K/mTOR pathway is a promising therapeutic approach in patients with ALL. Greater antileukemic activity of dual PI3K/mTORC1/C2 inhibitors appears to be due to the redundant function of PI3K and mTOR. Clinical trials examining dual PI3K/mTORC1/C2 inhibitors in patients with B-precursor ALL are warranted, and should not be restricted to particular genetic subtypes
Sampling Plans for Control-Inspection Schemes Under Independent and Dependent Sampling Designs With Applications to Photovoltaics
The evaluation of produced items at the time of delivery is, in practice,
usually amended by at least one inspection at later time points. We extend the
methodology of acceptance sampling for variables for arbitrary unknown
distributions when additional sampling infor- mation is available to such
settings. Based on appropriate approximations of the operating characteristic,
we derive new acceptance sampling plans that control the overall operating
characteristic. The results cover the case of independent sampling as well as
the case of dependent sampling. In particular, we study a modified panel
sampling design and the case of spatial batch sampling. The latter is advisable
in photovoltaic field monitoring studies, since it allows to detect and analyze
local clusters of degraded or damaged modules. Some finite sample properties
are examined by a simulation study, focusing on the accuracy of estimation
Study of the acoustic signature of UHE neutrino interactions in water and ice
The production of acoustic signals from the interactions of ultra-high energy
(UHE) cosmic ray neutrinos in water and ice has been studied. A new
computationally fast and efficient method of deriving the signal is presented.
This method allows the implementation of up to date parameterisations of
acoustic attenuation in sea water and ice that now includes the effects of
complex attenuation, where appropriate. The methods presented here have been
used to compute and study the properties of the acoustic signals which would be
expected from such interactions. A matrix method of parameterising the signals,
which includes the expected fluctuations, is also presented. These methods are
used to generate the expected signals that would be detected in acoustic UHE
neutrino telescopes.Comment: 21 pages and 13 figure
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