1,236 research outputs found
Evolving an optimal decision template for combining classifiers.
In this paper, we aim to develop an effective combining algorithm for ensemble learning systems. The Decision Template method, one of the most popular combining algorithms for ensemble systems, does not perform well when working on certain datasets like those having imbalanced data. Moreover, point estimation by computing the average value on the outputs of base classifiers in the Decision Template method is sometimes not a good representation, especially for skewed datasets. Here we propose to search for an optimal decision template in the combining algorithm for a heterogeneous ensemble. To do this, we first generate the base classifier by training the pre-selected learning algorithms on the given training set. The meta-data of the training set is then generated via cross validation. Using the Artificial Bee Colony algorithm, we search for the optimal template that minimizes the empirical 0–1 loss function on the training set. The class label is assigned to the unlabeled sample based on the maximum of the similarity between the optimal decision template and the sample’s meta-data. Experiments conducted on the UCI datasets demonstrated the superiority of the proposed method over several benchmark algorithms
Reduction of the size of datasets by using evolutionary feature selection: the case of noise in a modern city
Smart city initiatives have emerged to mitigate the negative effects of a very fast growth of urban areas. Most of the population in our cities are exposed to high levels of noise that generate discomfort and different health problems. These issues may be mitigated by applying different smart cities solutions, some of them require high accurate noise information to provide the best quality of serve possible. In this study, we have designed a machine learning approach based on genetic algorithms to analyze noise data captured in the university campus. This method reduces the amount of data required to classify the noise by addressing a feature selection optimization problem. The experimental results have shown that our approach improved the accuracy in 20% (achieving an accuracy of 87% with a reduction of up to 85% on the original dataset).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.
This research has been partially funded by the Spanish MINECO and FEDER projects TIN2016-81766-REDT (http://cirti.es), and TIN2017-88213-R (http://6city.lcc.uma.es)
Оценка сортов фасоли овощной (Phaseolus vulgaris) на адаптивность и клубенькообразующую способность в условиях лесостепи Приобья
Relevance. From an agrotechnical point of view, beans are a valuable crop capable of greening agriculture. Legumes have the ability to enter into symbiotic relationships with nodule nitrogen-fixing bacteria and assimilate atmospheric nitrogen. The creation of highly efficient plant-microbial systems in agrocenoses by breeding new varieties of legumes with a high symbiotic potential is a promising direction that makes it possible to control the efficiency of plant biomass accumulation and the quality of agricultural products. There is a need to evaluate varieties for adaptability and nodule-forming ability to implement breeding programs to create highly productive and high-quality varieties that can realize the genetic potential of productivity in the sharply continental climate.Materials and methods. On the basis of the Federal State Budgetary Educational Institution of Higher Education Novosibirsk State Agrarian University in 2018-2020, an assessment was made of green bean varieties of different ecological and geographical origin with a bush type of growth. Experimental fields are located in the village of Michurinsky (left bank of Novosibirsk) and the educational and production farm "Garden of Michurintsev" (right bank of Novosibirsk). The study of samples in terms of adaptability parameters, as well as the ability to form nodules, was performed in accordance with generally accepted methods. We took into account the characteristics that affect the productivity of the crop - the number and weight of beans per plant, the weight of one bean, and the yield. The aim of the work is to evaluate the varieties of vegetable beans for adaptability and nodule-forming ability in the conditions of the forest-steppe of the Siberian region.Results. When forming the symbiotic apparatus, the growth conditions were taken into account. It has been established that high rates of biomass are observed on the territory of the village of Michurinsky. Varieties Morena and Maguyra are characterized by intensive growth in the experimental field of the village of Michurinsky, varieties Zoluyshka and Solnyshko – the educational and production farm "Garden of Michurintsev". The total number of nodules per plant varied from 29 (Kormilitsa) to 66. (Zoluyshka), active nodules – from 9 (Kormilitsa) to 49 (Zoluyshka). It is noted that the varieties Solnyshko and Zoluyshka have high rates of general adaptive ability and breeding value of the genotype. A strong relationship has been established between the characteristics of leaf mass and the number of active nodules, the number of active nodules and the leaf surface area; average - between the number of active nodules and plant biomass.Актуальность. С агротехнической точки зрения фасоль является ценной культурой, способной экологизировать земледелие. Бобовые культуры обладают способностью вступать в симбиотические отношения с клубеньковыми азотфиксирующими бактериями и ассимилировать азот воздуха. Создание высокоэффективных растительно-микробных систем в агроценозах путем селекции новых сортов бобовых с высоким симбиотическим потенциалом – перспективное направление, позволяющее контролировать эффективность накопления биомассы растений и качество сельскохозяйственной продукции. Возникает необходимость оценки образцов на адаптивность и клубенькообразующую способность для реализации селекционных программ по созданию высокопродуктивных сортов, способных реализовать генетический потенциал продуктивности в резко-континентальном климате.Материалы и методы. На базе ФГБОУ ВО Новосибирский ГАУ в 2018-2020 годах проведена оценка сортов фасоли овощной разного эколого-географического происхождения с кустовым типом роста. Опытные поля расположены в поселке Мичуринский (левый берег г. Новосибирска) и учебно-производственном хозяйстве ≪Сад Мичуринцев≫ (правый берег г. Новосибирска). Изучение образцов по параметрам адаптивности, а также способности формирования клубеньков выполняли в соответствии с общепринятыми методиками. Учитывали признаки продуктивности: число и масса бобов с растения, масса одного боба, урожайность. Целью работы являлась оценка сортов фасоли овощной на адаптивность и клубенькообразующую способность в условиях лесостепи Приобья.Результаты. При формировании симбиотического аппарата учитывали условия произрастания. На территории п. Мичуринский установлены высокие показатели по биомассе. Сорта Морена и Магура характеризовались интенсивным ростом на опытном поле п. Мичуринский, сорта Золушка и Солнышко – УПХ ≪Сад Мичуринцев≫. Общее число клубеньков на растении варьировало от 29 (Кормилица) до 66 шт. (Золушка), активных клубеньков – от 9 (Кормилица) до 49 шт. (Золушка). Отмечено, что сорта Солнышко и Золушка обладали высокими показателями общей адаптивной способности и селекционной ценности генотипа. Установлена сильная взаимосвязь между признаками масса листьев и число активных клубеньков, число активных клубеньков и площадь листовой поверхности; средняя – между числом активных клубеньков и биомассой растения
Convection enhanced delivery for treating brain tumors and selected neurological disorders: symposium review
Femtosecond Carrier Dynamics in In2O3Nanocrystals
We have studied carrier dynamics in In2O3nanocrystals grown on a quartz substrate using chemical vapor deposition. Transient differential absorption measurements have been employed to investigate the relaxation dynamics of photo-generated carriers in In2O3nanocrystals. Intensity measurements reveal that Auger recombination plays a crucial role in the carrier dynamics for the carrier densities investigated in this study. A simple differential equation model has been utilized to simulate the photo-generated carrier dynamics in the nanocrystals and to fit the fluence-dependent differential absorption measurements. The average value of the Auger coefficient obtained from fitting to the measurements was γ = 5.9 ± 0.4 × 10−31 cm6 s−1. Similarly the average relaxation rate of the carriers was determined to be approximately τ = 110 ± 10 ps. Time-resolved measurements also revealed ~25 ps delay for the carriers to reach deep traps states which have a subsequent relaxation time of approximately 300 ps
Polaron spin current transport in organic semiconductors
In spintronics, pure spin currents play a key role in transmitting, processing and storing information. A pure spin current is a flow of electron spin angular momentum without a simultaneous flow of charge current. It can be carried by conduction electrons or magnons and has been studied in many inorganic metals, semiconductors and insulators, but not yet in organic semiconductors. Charge carriers in π-conjugated organic materials are localized spin-1/2 polarons which move by hopping, but the mechanisms of their spin transport and relaxation are not well understood. Here we use ferromagnetic resonance spin pumping in a ferromagnet/conjugated polymer/nonmagnetic spin-sink trilayer to demonstrate the ability of polarons to carry pure spin currents over hundreds of nanometres with long spin relaxation times of up to a millisecond and to exhibit Hanle precession. By systematically comparing charge and spin transport on the same trilayer we show that spin-orbit coupling mediates spin relaxation at room temperature.This work was supported by the Cabinet Office, Government of Japan through its “Funding Program for Next Generation World-Leading Researchers”, PRESTO-JST “Innovative nano-electronics through interdisciplinary collaboration among material, device and system layers”, the Asahi Glass Foundation and the Engineering and Physical Sciences Research Council (EPSRC).This is the accepted version of the article. The final version was published in Nature Physics and is available at http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys2901.html. Nature Publishing Group's licence and reuse policy is available at http://www.nature.com/authors/policies/license.html
Methylthioadenosine reprograms macrophage activation through adenosine receptor stimulation
Regulation of inflammation is necessary to balance sufficient pathogen clearance with excessive tissue damage. Central to regulating inflammation is the switch from a pro-inflammatory pathway to an anti-inflammatory pathway. Macrophages are well-positioned to initiate this switch, and as such are the target of multiple therapeutics. One such potential therapeutic is methylthioadenosine (MTA), which inhibits TNFα production following LPS stimulation. We found that MTA could block TNFα production by multiple TLR ligands. Further, it prevented surface expression of CD69 and CD86 and reduced NF-KB signaling. We then determined that the mechanism of this action by MTA is signaling through adenosine A2 receptors. A2 receptors and TLR receptors synergized to promote an anti-inflammatory phenotype, as MTA enhanced LPS tolerance. In contrast, IL-1β production and processing was not affected by MTA exposure. Taken together, these data demonstrate that MTA reprograms TLR activation pathways via adenosine receptors to promote resolution of inflammation. © 2014 Keyel et al
Performance evaluation on an air-cooled heat exchanger for alumina nanofluid under laminar flow
This study analyzes the characteristics of alumina (Al2O3)/water nanofluid to determine the feasibility of its application in an air-cooled heat exchanger for heat dissipation for PEMFC or electronic chip cooling. The experimental sample was Al2O3/water nanofluid produced by the direct synthesis method at three different concentrations (0.5, 1.0, and 1.5 wt.%). The experiments in this study measured the thermal conductivity and viscosity of nanofluid with weight fractions and sample temperatures (20-60°C), and then used the nanofluid in an actual air-cooled heat exchanger to assess its heat exchange capacity and pressure drop under laminar flow. Experimental results show that the nanofluid has a higher heat exchange capacity than water, and a higher concentration of nanoparticles provides an even better ratio of the heat exchange. The maximum enhanced ratio of heat exchange and pressure drop for all the experimental parameters in this study was about 39% and 5.6%, respectively. In addition to nanoparticle concentration, the temperature and mass flow rates of the working fluid can affect the enhanced ratio of heat exchange and pressure drop of nanofluid. The cross-section aspect ratio of tube in the heat exchanger is another important factor to be taken into consideration
Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
We report a measurement of the bottom-strange meson mixing phase \beta_s
using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays
in which the quark-flavor content of the bottom-strange meson is identified at
production. This measurement uses the full data set of proton-antiproton
collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment
at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity.
We report confidence regions in the two-dimensional space of \beta_s and the
B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2,
-1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in
agreement with the standard model expectation. Assuming the standard model
value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +-
0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +-
0.009 (syst) ps, which are consistent and competitive with determinations by
other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
Hepatitis B Therapy in Pregnancy
All decisions about initiating, continuing, or stopping therapy of the hepatitis B virus (HBV) during pregnancy must include an analysis of the risks and benefits for mother and fetus. The trimester of the pregnancy and the stage of the mother’s liver disease are important factors. Treatment in the third trimester may be initiated to aid in preventing perinatal transmission, which appears to be most pronounced in mothers with high viral loads. Consideration of initiating treatment in the third trimester should occur after a high viral load is documented in the latter part of the second trimester, to allow adequate time for initiation of antiviral therapy with significant viral suppression before delivery. This discussion should include the topic of breastfeeding, because it is generally not recommended while receiving antiviral therapy. Currently, lamivudine and tenofovir appear to be the therapeutic options with the most reasonable safety data in pregnancy
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