1,339 research outputs found
Microwave burst with fine spectral structures in a solar flare on 2011 August 9
On August 9, 2011, there was an X6.9 flare event occurred near the west limb
of solar disk. From the observation obtained by the spectrometer of the Chinese
Solar Broadband Radio Spectrometer in Huairou (SBRS/Huairou) around the flare,
we find that this powerful flare has only a short-duration microwave burst of
about only 5 minutes, and during the short-duration microwave burst, there are
several kinds of fine structures on the spectrogram. These fine structures
include very short-period pulsations, millisecond spike bursts, and type III
bursts. The most interesting is that almost all of the pulses of very
short-period pulsation (VSP) are structured by clusters of millisecond
timescales of spike bursts or type III bursts. And there exists three different
kinds of frequency drift rates in the VSP: the frequency drift rates with
absolute value of about 55 - 130 MHz s^{-1} in the pulse groups, the frequency
drift rates with absolute value of about 2.91 - 16.9 GHz s^{-1} on each
individual pulse, and the frequency drift rates with absolute value of about 15
- 25 GHz s) at each individual spike burst or type III burst.Comment: 5 pages, 3 figure
Differentiated thyroid carcinoma : diagnostic and therapeutic studies
Differentiated thyroid carcinoma (DTC) has favorable prognosis with high cure rate under treatment of thyroidectomy followed by radiotherapy. However, therapeutic efficiency decreases when dedifferentiation occurs. One of the purposes in this study is to use pharmaceuticals intervention to promote therapeutic responsiveness in thyroid carcinomas. Lithium compound and retinoid derivatives have been applied in thyroid cancer patients and in normal and thyroid cancer cell lines. The results indicate that Lithium compound doesn__t influence either iodine uptake in vivo and in vitro conditions or iodine efflux in cell lines observed. Retinoid, Bexarotene, slightly increases iodine uptake in thyroid cancer patients but does not reach the therapeutic level. In attempt to find efficient diagnostic markers, 156 patient samples including subsets of thyroid carcinomas and benign thyroid disorders have been investigated using immunohistochemistry in tissue micro-array sections. The results indicate that combination of protein expression of NIS, FN and Gal-3 may distinguish benign tumors from malignant thyroid carcinomas with high accuracy. As thyroid cancer patients have high survival rate, efficient and sensitive screening tool is crucial for follow up in DTC. In this study, thyroglobulin (Tg) of over 600 patients has been studies at unicenter with uniformed treatment. The results prove that multiple tests of Tg at fix time points may predict DTC prognosis and death.LEI Universiteit LeidenStichting Nationaal Fonds tegen Kanker, J.E.Jurriaanse Stichting, Genzyme,Diabetes, endocriene pathofysiologie en endocriene tumore
Efecto de reemplazar estearina por oleína de palma en galletas de papa horneadas
Potato cookies were formulated by replacing red palm stearin (RPS) by red palm olein (RPOL) at 0, 17 and 35%, and then baked at 160, 180 and 200 °C for 10, 12 and 15 min. The sensory analysis, using an orthogonal test, showed that a RPS-RPOL ratio of 65:35, baking temperature of 160 ºC, and baking time 12 min were the optimal conditions. Cookies made from 65% RPS + 35% RPOL composition exhibited 0.6 times less squalene, but 1.5 times more β-carotene, tocopherols and tocotrienols than the mixture of RPS and RPOL at 100:0. In addition, cookies with superior oxidative stability were obtained at a lower temperature (160 ºC) and short baking time (10 min). This study demonstrates that the application of RPOL and RPS blending can positively enhance the nutritional properties and oxidative stability of baked food, and that using potato in the baking processing may be beneficial.Las galletas de papa fueron formuladas reemplazando estearina de palma roja (RPS) por oleina de palma roja (RPOL) al 0, 17 y 35%, y posteriormente horneadas a 160, 180 y 200°C durante 10, 12 y 15 min. El análisis sensorial utilizando una prueba ortogonal mostró que la relación RPS-RPOL 65:35, la temperatura de horneado 160 ºC, y el tiempo de horneado 12 min fueron las condiciones óptimas. Las galletas hechas de 65% RPS + 35% RPOL presentan 0,6 veces menos de escualeno, pero 1,5 veces más β-caroteno, tocoferoles y tocotrienoles que la mezcla de RPS y RPOL en 100:0. Por otra parte, las galletas con mayor estabilidad oxidativa se obtuvieron a menor temperatura (160 ºC) y menor tiempo de horneado (10 min). Este estudio demuestra que la mezcla RPOL y RPS puede mejorar positivamente las propiedades nutricionales y la estabilidad oxidativa de los alimentos horneados, y que el uso de papa en el procesamiento de hornear puede ser beneficioso
PSO-based Parameter Estimation of Nonlinear Kinetic Models for β-Mannanase Fermentation
Particle swarm optimization (PSO), as a novel evolutionary algorithm involved in social interaction for global space search, was firstly used in kinetic parameter estimation. Based on three developed nonlinear kinetic equations for bacterial cell growth, total sugar utilization and β-mannanase production by Bacillus licheniformis under the support of a batch fermentation process, various PSO algorithms as well as gene algorithms (GA) were developed to estimate kinetic parameters. The performance comparison among these algorithms indicates the improved PSO (Trelea 1) is most suitable for kinetic parameter estimation of β-mannanase fermentation. In order to find the physical-chemical-meanings of kinetic parameters from many optimized results, multiobjective optimization with a normalized weight method was adopted. The 9 desired parameters in equations were obtained by the Trelea 1 type PSO with two batches fermentation data, and the results predicted by the models were also in good agreement with the experimental observations
3D reconstruction of train accident scene based on monocular image
To help with making an emergency rescue plan for train accidents, a rapid 3D reconstruction
method of train accident scene based on a monocular image was proposed. Taking two
camera projection models for different application scenarios into consideration, the SIFT algorithm
was introduced to extract and match image feature with the CAD model of an accident train.
Geometric constraints between carriages were provided to transform the 3D reconstruction to
solving a nonlinear least square problem with constraints, by which the position and pose of accident
subjects were reduced at last. To quantitatively and qualitatively verify the calculation performance
of this method, the mimicked train accident scene and real train accident scene were
respectively used to carry out 3D reconstruction. The precise finite camera projection model was
applied in the mimicked train accident scene to carry out offline calibration, and the stable
pin-hole model was adopted in the real train accident scene to carry out auto calibration. Analysis
result shows that through quantitative analysis of mimicked scene the maximal and average relative
error of 8 nodes for measurement in reconstructing two carriages are 4.54% and 1.85% respectively.
Through qualitative analysis of the real scene, the 3D reduction of position and pose
for carriages can also be realized with combining the topographic information correction. The
whole accident environmental panorama can be reduced visually with the help of 3D visualization
engine. This method can also be used in developing emergency rescue electronic sand table for
train accident analysis and safety education
Propiedades fisicoquímicas de snacks extrusionados de patatas y batatas con aceite de palma roja
Extruded potato (P) and sweet potato (SP) products with red palm oil (RPO) were prepared under different conditions. Superior product characteristics such as sensory score, expansion ratio, and water solubility index, among others, were obtained at high extrusion temperature (150-155 °C) and low water feed rate to the extruder (50.4-50.8 mL/min). The optimal products, P1 and SP1, had high micronutrients as their total contents of β-carotene, squalene, tocopherols, and tocotrienols were 883.2, 304.4, 262.4, and 397.0 mg/kg of oil, respectively. The average peroxide value was 4.3 meq O2/kg oil, p-anisidine value 3.3, and induction period (100 °C) 11.4 h. Moreover, RPO extruded with P showed a better extrusion behavior but lower micronutrient retention and oxidative stability than that extruded with SP. Thus, the finding herein is important for investigating extrusion conditions, increasing variety, improving nutritional quality, assessing applicability and predicting the shelf-life of RPO-P/SP-extruded food.Se prepararon snacks extrusionados de patatas (P) y batatas (B) con aceite de palma roja (APR) en diferentes condiciones. Se obtuvieron unas características superiores de los productos, como puntuación sensorial, relación de expansión, índice soluble en agua, entre otros, a alta temperatura de extrusión (150-155 °C) y baja velocidad de alimentación de agua al extrusionador (50,4-50,8 mL/min). Los productos óptimos, P1 y SP1, contenían altos micronutrientes ya que su contenido total de β-caroteno, escualeno, tocoferoles y tocotrienoles fue de 883,2; 304,4; 262,4 y 397,0 mg/kg de aceite, respectivamente. El índice de peróxido promedio fue de 4,3 meq O2/kg de aceite, el valor de p-anisidina de 3,3 y el período de inducción a 100 °C de 11,4 h. Además, el APR utilizado para la extrusión de P mostró un mejor comportamiento de extrusión, pero menor retención de micronutrientes y estabilidad oxidativa que el extrusionado con SP. Por lo tanto, los datos aquí obtenidos son importantes para profundizar en las condiciones de extrusión, aumentar la variedad, mejorar la calidad nutricional, evaluar la aplicabilidad y predecir la vida útil de los alimentos extrusionados con APR-P / B
Neutrophil-initiated myocardial inflammation and Its modulation by B-type natriuretic peptide: a potential therapeutic target
Activation of neutrophils is a critically important component of the innate immune response to bacterial and chemical stimuli, and culminates in the “neutrophil burst”, which facilitates neutrophil phagocytosis via the release of superoxide anion radical (O₂-) from NADPH oxidase. Excessive and/or prolonged neutrophil activation results in substantial tissue injury and increases in vascular permeability - resulting in sustained tissue infiltration with neutrophils and monocytes, and persistent vasomotor dysfunction. Cardiovascular examples of such changes include acute and chronic systolic and diastolic heart failure (“heart failure with preserved ejection fraction”), and the catecholamine-induced inflammatory disorder takotsubo syndrome. We have recently demonstrated that B-type natriuretic peptide (BNP), acting via inhibition of activation of neutrophil NADPH oxidase, is an important negative modulator of the “neutrophil burst”, though its effectiveness in limiting tissue injury is partially lost in acute heart failure. The potential therapeutic implications of these findings, regarding the development of new means of treating both acute and chronic cardiac injury states, are discussed.Saifei Liu, Yuliy Y. Chirkov and John D. Horowit
Water wave propagation and scattering over topographical bottoms
Here I present a general formulation of water wave propagation and scattering
over topographical bottoms. A simple equation is found and is compared with
existing theories. As an application, the theory is extended to the case of
water waves in a column with many cylindrical steps
Error characterisation of global active and passive microwave soil moisture data sets
Understanding the error structures of remotely sensed soil moisture products is essential for correctly interpreting observed variations and trends in the data or assimilating them in hydrological or numerical weather prediction models. Nevertheless, a spatially coherent assessment of the quality of the various globally available data sets is often hampered by the limited availability over space and time of reliable in-situ measurements. This study explores the triple collocation error estimation technique for assessing the relative quality of several globally available soil moisture products from active (ASCAT) and passive (AMSR-E and SSM/I) microwave sensors. The triple collocation technique is a powerful tool to estimate the root mean square error while simultaneously solving for systematic differences in the climatologies of a set of three independent data sources. In addition to the scatterometer and radiometer data sets, we used the ERA-Interim and GLDAS-NOAH reanalysis soil moisture data sets as a third, independent reference. The prime objective is to reveal trends in uncertainty related to different observation principles (passive versus active), the use of different frequencies (C-, X-, and Ku-band) for passive microwave observations, and the choice of the independent reference data set (ERA-Interim versus GLDAS-NOAH). <br><br> The results suggest that the triple collocation method provides realistic error estimates. Observed spatial trends agree well with the existing theory and studies on the performance of different observation principles and frequencies with respect to land cover and vegetation density. In addition, if all theoretical prerequisites are fulfilled (e.g. a sufficiently large number of common observations is available and errors of the different data sets are uncorrelated) the errors estimated for the remote sensing products are hardly influenced by the choice of the third independent data set. The results obtained in this study can help us in developing adequate strategies for the combined use of various scatterometer and radiometer-based soil moisture data sets, e.g. for improved flood forecast modelling or the generation of superior multi-mission long-term soil moisture data sets
Robust DOA Estimation for Sources with Known Waveforms Against Doppler Shifts via Oblique Projection
As known, utilization of the information about signal waveform can improve the direction of arrival (DOA) estimation results. However, with a fast moving platform, Doppler effect occurs, which distorts the known waveforms and may result in large DOA estimation bias and even error for conventional DOA estimation methods for sources with known waveforms. To deal with this problem, a robust DOA estimation method for sources with known waveforms against Doppler shifts is developed. The proposed method first transforms the nonlinear mixing of Doppler shifts in the model to an approximately linear one using discrete-time Fourier transform (DTFT) and finite Taylor series expansion. Then, multiple oblique projectors are constructed to separate each component corresponding to different order of derivatives. Finally, estimations of DOAs, complex amplitudes and Doppler shifts are obtained simultaneously. Simulation results show that the proposed method has a much more robust DOA estimation performance than existing methods for sources with known waveforms
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