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Influence of tributaries on downstream bed sediment grain sizes under flysch conditions

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Journal of Mountain Science 2021年第4期18卷 847-862页

作者： SMAZAK Ivan GALLA tomas Department of Physical Geography and Geoecology Faculty of ScienceUniversity of OstravaChittussiho 1071000 OstravaCzech Republic

Tributaries are one of the most important factors contributing to variability in the downstream evolution of bed sediment grain *** primary aim of this work is to evaluate the response of the bed sediment texture in the recipient channel induced by ten tributaries of the?ernáOstravice stream and find reach-scale and catchment-scale parameters that would be able to predict this *** research was based on collecting information on the grain size distributions at sites adjacent to confluence zones.A significant change in sediment texture occurred in the vicinity of five *** the other factors contributing to grain size variability(e.g.,local channel geometry,lithology,and lateral sediment sources),it was assumed that only four of them were associated with a sufficient bedload influx to alter the sediment calibre below the ***,a significant morphological effect in the form of a large confluence bar was observed in one *** tributaries had several common features:(i)they had a larger relative catchment area than that of nonsignificant tributaries;(ii)they were characterized by different bed grain sizes,with some exceptions;and(iii)they had a higher unit stream power close to the confluence in relation to that of the *** characteristics were represented by the proposed relative parameters,including the relative unit stream power and bed material texture,which allowed the best classification of significant and nonsignificant *** their simplified form,the parameters described the transport capacity and grain size distribution,which were generally considered to be primary factors responsible for a redefinition of the sediment texture in the recipient ***,it should be noted that these results are subject to some degree of uncertainty due to the relatively small sample size of only 10 tributaries.

关键词： Tributary Bed sediments Headwater streams Flysch Carpathians

Letters to the Editor

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Hepatobiliary & Pancreatic Diseases International 2016年第4期15卷 443-445页

作者： tomas S Bexelius Rickard Ljung Upper Gastrointestinal Research Department of Molecular Medicine and Surgeryand Department of Medical Epidemiology and BiostatisticsKarolinska Institute Department of Environmental Medicine Karolinska Institute Stockholm Sweden Luis A Garcia Rodriguez Centro Espa?ol de Investigación Farmacoepidemiológica

The Editor welcomes submissions for possible publication in the Letters to the Editor *** commenting on an article published in the Journal or other interesting pieces will be considered if they are received within 6 weeks of the time the article was *** of the article being commented on will be given an opportunity to offer a timely response to the letter Authors of letters will be notified that the letter has been received. Unpublished letters cannot be returned.

关键词： welcomes matching pieces obesity alcohol letter rendering adjustment ascertain excluded

Natural capital accounting perspectives:a pragmatic way forward

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Ecosystem Health and Sustainability 2019年第1期5卷 237-241,I0016页

作者： Kerry Turner tomas Badura Silvia Ferrini Centre for Social and Economic Research on the Global Environment(CSERGE) School of Environmental SciencesUniversity of East AngliaNorwichUK Global Change Research Institute Czech Academy of SciencesBrnoCzech Republic Department of Political and International Sciences University of SienaSienaItaly

Introduction:Recent debates surrounding the application of natural capital accounting(NCA)have produced several approaches to further develop this system,as well as highlighted a number of conceptual and methodological issues that need to be resolved before mainstreaming NCA into policy and decision *** argue that prolonged debate over the value concepts(i.e.,exchange versus other values)underpinning different modifications to NCA has slowed progress in experimentation and uptake by ***:Consequently we propose three broad approaches which can be progressed in parallel to reinvigorate experimentation with the NCA principles and practice,while at the same time generating policy relevant tools and evidence bases for decision *** three approaches are;extended SNA accounting anchored to the use of exchange values;a complementary accounts network(CAN)that utilizes plural values as supplementary accounts to the SNA system;and wealth accounting that focuses on measures of welfare and *** three approaches are complementary and data developed in any one can inform the other ***:We contend that CAN offers the most flexibility and opportunities to progress short term support for decision making on environmental issues which are now becoming urgent.

关键词： Natural capital accounting SEEA ecosystem accounting wealth accounting exchange values welfare values

Progress of renewable electricity replacing fossil fuels

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Global Energy Interconnection 2018年第1期1卷 48-52页

作者： tomas Kaberger Chalmers University of Technology SE 41279 GoteborgSweden

Dramatic fall in costs of renewable energy in the last 24 months has not only accelerated the replacement of fossil fuels by renewable energy in electricity generation. The low cost renewable electricity is now starting to replace fossil fuels in other sectors. One reason is that renewable electricity is now cheaper per unit energy than oil, about the same price as fossil methan but, still, more expensive than coal. Another reason is that electricity often offer other opportunities, such as cheaper transport, better control, higher energy efficiency in final production of energy services and lower local environmental costs.

关键词： Industrial learning Renewable energy Fossil fuel substitution

Behavioral dependent dispersal in the invasive round goby Neogobius melanostomus depends on population age

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Current Zoology 2015年第3期61卷 529-542页

作者： Magnus THORLACIUS Gustav HELLSTROM tomas BRODIN Department of Ecology and Environmental Science Umea University Linnaeus v/ig 6 90187 Umeh Sweden

Biological invasions cause major ecological and economic costs in invaded habitats. The round goby Neogobius me- lanostomus is a successful invasive species and a major threat to the biodiversity and ecological function of the Baltic Sea. It is native to the Ponto-Caspian region and has, via ballast water transport of ships, invaded the Gulf of Gdansk in Poland. Since 1990, it has spread as far north as Raahe in Northern Finland （64~41 ＂04＂N, 24~28＂44＂E）. Over the past decade, consistent indi- vidual differences of behavioral expressions have been shown to explain various ecological processes such as dispersal, survival or reproduction. We have previously shown that new and old populations differ in personality trait expression. Individuals in new populations are bolder, less sociable and more active than in old populations. Here we investigate if the behavioral differentiation can be explained by phenotype-dependent dispersal. This was investigated by measuring activity, boldness and sociability of in- dividually marked gobies, and subsequently allowing them to disperse in a system composed of five consecutive tanks connected by tubes. Individual dispersal tendency and distance was measured. Our results revealed that in newly established populations, more active individuals disperse sooner and that latency of a group to disperse depends on the mean sociability of the group. This indicates the presence of personality dependent dispersal in this species and that it is maintained at the invasion front but lost as the populations get older

关键词： Personality Activity Dispersal Round goby Neogobius melanostomus Species invasions

Approximation of the Mean Escape Time for a Tilted Periodic Potential

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Communications in Computational Physics 2019年第1期25卷 1-40页

作者： Tamra Heberling Lisa Davis tomas Gedeon Los Alamos National Laboratory XTD-SSLos AlamosNM87545USA Department of Mathematical Sciences Montana State UniversityBozemanMT59717-2400USA

We present a formula approximating the mean escape time(MST)of a particle from a tilted multi-periodic potential *** potential function consists of a weighted sum of a finite number of component functions,each of which is *** this particular case,the least period of the potential function is a common period amongst all of its component *** approximation of the MST for the potential function is derived,and this approximation takes the form of a product of the MSTs for each of the individual periodic component *** first example illustrates the computational advantages of using the approximation for model validation and parameter tuning in the context of the biological application of DNA *** also use this formula to approximate the MST for an arbitrary tilted periodic potential by the product of MSTs of a finite number of its Fourier *** examples using truncated Fourier series are presented and analyzed.

关键词： Brownian Ratchet multi-periodic potential tilted periodic potential Fokker-Plank equation

Automatic detection of Acacia longifolia invasive species based on UAV-acquired aerial imagery

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Information Processing in Agriculture 2022年第2期9卷 276-287页

作者： Carolina Goncalves Pedro Santana tomas Brandao Magno Guedes ISCTE-Instituto Universitario de Lisboa Portugal Instituto de Telecomunicacoes LisboaPortugal Information Sciences and Technologies and Architecture Research Center(ISTAR-IUL) LisboaPortugal IntRoSys SA Portugal

The Acacia longifolia species is known for its rapid growth and dissemination,causing loss of biodiversity in the affected *** order to avoid the uncontrolled spread of this species,it is important to effectively monitor its distribution on the agroforestry *** this purpose,this paper proposes the use of Convolutional Neural Networks(CNN)for the detection of Acacia longifolia,from images acquired by an unmanned aerial *** models based on the same CNN architecture were *** classifies image patches into one of nine possible classes,which are later converted into a binary model;this model presented an accuracy of 98:6%and 98:5%in the validation and training sets,*** second model was trained directly for binary classification and showed an accuracy of 98:8%and 98:7%for the validation and test sets,*** results show that the use of multiple classes,useful to provide the aerial vehicle with richer semantic information regarding the environment,does not hamper the accuracy of Acacia longifolia detection in the classifier’s primary *** presented system also includes a method for increasing classification’s accuracy by consulting an expert to review the model’s predictions on an automatically selected sub-set of the samples.

关键词： Pattern recognition Convolutional neural networks Invasive plants Acacia longifolia

Investigating the coagulation of non-proteinaceous algal organic matter: Optimizing coagulation performance and identification of removal mechanisms

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Journal of Environmental Sciences 2019年第5期31卷 25-34页

作者： Jana Naceradska Katerina Novotna Lenka Cermakova tomas Cajthaml Martin Pivokonsky Institute of Hydrodynamics of the Czech Academy of Sciences Institute of Microbiology of the Czech Academy of Sciences

The removal of algal organic matter(AOM) is a growing concern for the water treatment industry worldwide. The current study investigates coagulation of non-proteinaceous AOM(AOM after protein separation), which has been minimally explored compared with proteinaceous fractions. Jar tests with either aluminum sulphate(alum) or polyaluminium chloride(PACl) were performed at doses of 0.2–3.0 mg Al per 1 mg of dissolved organic carbon in the p H range 3.0–10.5. Additionally, non-proteinaceous matter was characterized in terms of charge, molecular weight and carbohydrate content to assess the treatability of its different fractions. Results showed that only up to 25% of non-proteinaceous AOM can be removed by coagulation under optimized conditions. The optimal coagulation p H(6.6–8.0 for alum and 7.5–9.0 for PACl) and low surface charge of the removed fraction indicated that the prevailing coagulation mechanism was adsorption of non-proteinaceous matter onto aluminum hydroxide precipitates. The lowest residual Al concentrations were achieved in very narrow p H ranges, especially in the case of PACl. High-molecular weight saccharidelike organics were amenable to coagulation compared to low-molecular weight(< 3 k Da)substances. Their high content in non-proteinaceous matter(about 67%) was the reason for its low removal. Comparison with our previous studies implies that proteinaceous and nonproteinaceous matter is coagulated under different conditions due to the employment of diverse coagulation mechanisms. The study suggests that further research should focus on the removal of low-molecular weight AOM, reluctant to coagulate, with other treatment processes to minimize its detrimental effect on water safety.

关键词： Algal organic matter Chlorella vulgaris Coagulation Flocculation Non-proteinaceous matter Water treatment

Determination of frequencies of oscillations of cloud cavitation on a 2-D hydrofoil from high-speed camera observations

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Journal of Hydrodynamics 2016年第3期28卷 369-378页

作者： Patrik ZIMA tomas FURST Milan SEDLAR Martin KOMAREK Rostislav HUZLIK Institute of Thermomechanics of the CAS v.v.i.PragueCzech RepublicE-mail:zimap@it.cas.cz Faculty of Science Palacky University in OlomoucOlomoucCzech Republic Centre of Hydraulic Research LutinCzech Republic Faculty of Electrical Engineering and Communication Brno University of TechnologyBrnoCzech Republic

A method is presented to determine significant frequencies of oscillations of cavitation structures from high-speed camera recordings of a flow around a 2-D hydrofoil. The top view of the suction side of an NACA 2412 hydrofoil is studied in a transparent test section of a cavitation tunnel for selected cloud cavitation regimes with strong oscillations induced by the leading-edge cavity shedding. The ability of the method to accurately determine the dominant oscillation frequencies is confirmed by pressure measure- ments. The method can resolve subtle flow characteristics that are not visible to the naked eye. The method can be used for non- invasive experimental studies of oscillations in cavitating flows with adequate visual access when pressure measurements are not available or when such measurements would disturb the flow.

关键词： unsteady cavitation oscillation frequency high-speed camera observation