27,732 research outputs found
Gas phase reaction rates of some positive ions with water at 296 K
Measuring rate constants for reactions of various gas phases with water by flowing afterglow techniqu
Evaluation of auto regressive integrated moving average (arima) and artificial neural networks (ann) in the prediction of effluent quality of a wastewater treatment system
The main objective of wastewater treatment is to purify the water by degradation of organic matter in the water to anenvironmentally friendly status. To achieve this objective, some effluent (waste water) quality parameters such asChemical oxygen demand (COD) and Biochemical oxygen demand (BOD5) should be measured continuously in orderto meet up with the said objective and regulatory demands. However, through the prediction on water qualityparameters, effective guidance can be provided to comply with such demand without necessarily engaging in rigorouslaboratory analysis. Box-Jenkin’s Auto Regressive Integrated Moving Average (ARIMA) technique is one of the mostrefined extrapolation techniques for prediction while Artificial Neural Network (ANN) is a modern non-linear methodalso used for prediction. The Mean Absolute Error (MAE), Mean Absolute Percentage Error (MAPE), Root MeanSquare Error (RMSE) and Correlation coefficient (r) are used to evaluate the accuracy of the above-mentionedmodels. This paper examined the efficiency of ARIMA and ANN models in prediction of two major water qualityparameters (COD and BOD5) in a wastewater treatment plant. With the aid of R software, it was concluded that in allthe error estimates, ANNs models performed better than the ARIMA model, hence it can be used in the operation ofthe treatment system
Actively stressed marginal networks
We study the effects of motor-generated stresses in disordered three
dimensional fiber networks using a combination of a mean-field, effective
medium theory, scaling analysis and a computational model. We find that motor
activity controls the elasticity in an anomalous fashion close to the point of
marginal stability by coupling to critical network fluctuations. We also show
that motor stresses can stabilize initially floppy networks, extending the
range of critical behavior to a broad regime of network connectivities below
the marginal point. Away from this regime, or at high stress, motors give rise
to a linear increase in stiffness with stress. Finally, we demonstrate that our
results are captured by a simple, constitutive scaling relation highlighting
the important role of non-affine strain fluctuations as a susceptibility to
motor stress.Comment: 8 pages, 4 figure
Kinetics and mechanism of the formation of water cluster ions from O2(plus) and H2O in He, Ar, N2, and O2 at 296 K
The reaction sequence leading from O2(+) to H3O(+)-H2O was examined in He, Ar, N2 and O2 carrier gases in a flowing afterglow system. The rate constants for the reactions were measured and the kinetic analysis for their determination is presented. For M = N2, two new steps involving the formation and reaction of O2(+)-N2 were proposed and examined. The rate constants are discussed and compared with other experimental values
Endothelium-derived microparticles from chronically thromboembolic pulmonary hypertensive patients facilitate endothelial angiogenesis.
11 p.-4 fig.-1 tab.Background: Increased circulating levels of endoglin+ endothelial microparticles (EMPs) have been identified in several cardiovascular disorders, related to severity. Endoglin is an auxilary receptor for transforming growth factor β (TGF-β) important in the regulation of vascular structure.Results: We quantified the number of microparticles in plasma of six patients with chronic thromboembolic pulmonary hypertension (CTEPH) and age- and sex-matched pulmonary embolic (PE) and healthy controls and investigated the role of microparticle endoglin in the regulation of pulmonary endothelial function in vitro. Results show significantly increased levels of endoglin+ EMPs in CTEPH plasma, compared to healthy and disease controls. Co-culture of human pulmonary endothelial cells with CTEPH microparticles increased intracellular levels of endoglin and enhanced
TGF-β-induced angiogenesis and Smad1,5,8 phosphorylation in cells, without affecting BMPRII expression. In an in vitro model, we generated endothelium-derived MPs with enforced membrane localization of endoglin. Co-culture of these MPs with endothelial cells increased cellular endoglin content, improved cell survival and stimulated
angiogenesis in a manner similar to the effects induced by overexpressed protein.Conclusions: Increased generation of endoglin+ EMPs in CTEPH is likely to represent a protective mechanism supporting endothelial cell survival and angiogenesis, set to counteract the effects of vascular occlusion and endothelial damage.This research was supported by a project grant (PG 11/13/28765) from the British Heart Foundation and by grants from Ministerio de Economia y Competitividad of Spain (SAF2013-43421-R to CB)Peer reviewe
Fermentation of Artichokes
The application of fermentative processes to the problem of the industrial utilization of agricultural products and by-products for the production of organic acids and \u27solvents\u27 has been approached from a number of angles. During the course of related studies the possibility of the fermentative utilization of artichoke tubers was considered. In many ways this plant would provide an agricultural product highly suited to such purposes. The artichoke is indigenous to North America and grows freely in all parts of the country. It can be machine cultivated in the same manner as corn and can be stored in the ground until needed. It is extremely hardy, adapts itself to great variations in soil and climate and is resistant to frost, while the foliage is very resistant to the ravages of insects and fungous diseases. Yields have been reported of from seven tons up to twenty tons per acre
Basis invariant conditions for supersymmetry in the two-Higgs-doublet model
The minimal supersymmetric standard model involves a rather restrictive Higgs
potential with two Higgs fields. Recently, the full set of classes of
symmetries allowed in the most general two Higgs doublet model was identified;
these classes do not include the supersymmetric limit as a particular class.
Thus, a physically meaningful definition of the supersymmetric limit must
involve the interaction of the Higgs sector with other sectors of the theory.
Here we show how one can construct basis invariant probes of supersymmetry
involving both the Higgs sector and the gaugino-higgsino Higgs interactions.Comment: RevTex, 11 pages, v2-small section adde
Optimal flexibility for conformational transitions in macromolecules
Conformational transitions in macromolecular complexes often involve the
reorientation of lever-like structures. Using a simple theoretical model, we
show that the rate of such transitions is drastically enhanced if the lever is
bendable, e.g. at a localized "hinge''. Surprisingly, the transition is fastest
with an intermediate flexibility of the hinge. In this intermediate regime, the
transition rate is also least sensitive to the amount of "cargo'' attached to
the lever arm, which could be exploited by molecular motors. To explain this
effect, we generalize the Kramers-Langer theory for multi-dimensional barrier
crossing to configuration dependent mobility matrices.Comment: 4 pages, 4 figure
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