22 research outputs found
Physiological and cell ultrastructure disturbances in wheat seedlings generated by Chenopodium murale hairy root exudate.
Chenopodium murale L. is an invasive weed species significantly interfering with wheat crop. However, the complete nature of its allelopathic influence on crops is not yet fully understood. In the present study, the focus is made on establishing the relation between plant morphophysiological changes and oxidative stress, induced by allelopathic extract. Phytotoxic medium of C. murale hairy root clone R5 reduced the germination rate (24% less than control value) of wheat cv. Nata拧a seeds, as well as seedling growth, diminishing shoot and root length significantly, decreased total chlorophyll content, and induced abnormal root gravitropism. The R5 treatment caused cellular structural abnormalities, reflecting on the root and leaf cell shape and organization. These abnormalities mostly included the increased number of mitochondria and reorganization of the vacuolar compartment, changes in nucleus shape, and chloroplast organization and distribution. The most significant structural changes were observed in cell wall in the form of amoeboid protrusions and folds leading to its irregular shape. These structural alterations were accompanied by an oxidative stress in tissues of treated wheat seedlings, reflected as increased level of H2O2 and other ROS molecules, an increase of radical scavenging capacity and total phenolic content. Accordingly, the retardation of wheat seedling growth by C. murale allelochemicals may represent a consequence of complex activity involving both cell structure alteration and physiological processes.This is a post-peer-review, pre-copyedit version of an article published in Protoplasma. The final authenticated version is available online at: [http://dx.doi.org/10.1007/s00709-018-1250-0
Probabilistic model for competing risks
W pracy przedstawiono koncepcj臋 probabilistycznego modelowania wyst膮pienia r贸偶norodnych zagro偶e艅 stanu zdatno艣ci systemu technicznego. G艂贸wnym celem tego opracowania s膮 konstrukcje funkcji s艂u偶膮cych do analizowania konkuruj膮cych zagro偶e艅. Praca ta zosta艂a zainspirowana ksi膮偶k膮 [4], w kt贸rej rozwini臋te zosta艂y metody probabilistyczne maj膮ce szczeg贸lne zastosowania w biologii i medycynie. W punkcie 1 przedstawione s膮 funkcyjne charakterystyki niezawodno艣ciowe zaadaptowane na potrzeby badania niezawodno艣ci, bezpiecze艅stwa i zagro偶e艅 system贸w technicznych. Pokazane s膮 zwi膮zki mi臋dzy nimi. Najwa偶niejsze wyniki s膮 zestawione w punkcie 2, gdzie przedstawiono model konkuruj膮cych zagro偶e艅 i jego funkcyjne charakterystyki. W punkcie 3, podane s膮 dwa proste przyk艂ady, w kt贸rych zastosowano przedstawion膮 metod臋 modelowania probabilistycznego.This paper describes a concept of probabilistic modelling of different competing risks of a technical system ability state. The main purpose is the construction of functions to analyse competing risks. In Point 1, functional characteristics are introduced, adopted to investigation of reliability, safety and the threats of technical systems. Moreover, relationships between them are shown. The most important results are shown in Point 2, where the model of competing risks is introduced. In Point 3, there are given two simple examples of systems. For these systems, there were appointed the hazard rates, the crude sub-distribution functions for the particular competing risks, the partial crude hazard rates, and the partial crude sub-distribution functions. In this publication, attention is concentrated on functional characteristics applied in parametrical modelling of the threats of the system ability state. In analysis of competing risks with parametrical methods, the introduced functions and their parameters are easily interpret, in particular, the hazard rate. If occurrences of threats are independent, then the introduced model of competing risks can be applied to any probability distribution. In case of dependent competing risks, we should use methods of multidimensional probability methods, which are seldom applied. The multidimensional distributions can play key role in development of applications of competing risks analysis. The whole of study finishes short recapitulation and cited literature
Uwarunkowania transferu technologii w rolnictwie Republiki Konga
The majority of the population in Sub-Saharan Africa
is employed in agriculture. Nevertheless, the productivity
of the sector is relatively low in comparison with other regions
of the world. Based on convergence theory, technology
transfer can enhance growth. However, the effective transfer
of technology requires a certain absorption capacity from
the recipient. Based on the qualitative research on cassava
production in Congo Brazzaville, we identified key factors
that influence the transfer process. These factors have been
divided into four key areas: market, institutions, technology,
and social capability. Cassava production value chain in Ignie
region served as a case study for the evaluation of technology
transfer absorptive capacity in Congo agriculture. We
learned that the lack of agro-technical education, shortages in
infrastructure, unavailability of business services, and market
structure are among the main barriers of the intensification of
technology use in agriculture.W krajach Afryki Subsaharyjskiej znaczna cz臋艣膰 ludno艣ci zatrudniona jest w sektorze agrarnym, ale jego wydajno艣膰
i poziom technologiczny pozostaj膮 stosunkowo ma艂o rozwini臋te w por贸wnaniu z innymi regionami 艣wiata. Potencjalnym
sposobem na przezwyci臋偶enie problem贸w rolnictwa jest transfer technologii oraz wykorzystanie efektu konwergencji. Efektywno艣膰
tego procesu jest jednak zale偶na od mo偶liwo艣ci absorpcji technologii. Celem artyku艂u jest zidentyfikowanie kluczowych
czynnik贸w wp艂ywaj膮cych na wykorzystanie technologii w rolnictwie subsaharyjskim na przyk艂adzie upraw manioku w Kongu.
Na podstawie bada艅 jako艣ciowych (wywiady bezpo艣rednie, obserwacje) przeprowadzono analiz臋 uproszczonego 艂a艅cucha warto艣ci
produkcji manioku w Kongu. Stwierdzono wyst臋powanie istotnych barier o charakterze rynkowym, technologicznym,
instytucjonalnym i spo艂ecznym, wp艂ywaj膮cych na mo偶liwo艣ci absorbowania technologii. Chodzi przede wszystkim o braki
dotycz膮ce poziomu wykszta艂cenia ludno艣ci, dost臋pno艣ci rozwi膮za艅 infrastrukturalnych, struktury rynku oraz dost臋pno艣ci us艂ug
rozwoju biznesu, ale r贸wnie偶 o niewystarczaj膮ce rozwi膮zania instytucjonalne obejmuj膮ce transfer technologii zar贸wno o charakterze
komercyjnym, jak i niekomercyjnym
Three parameter model of the system lifetime with two types of risks
W pracy przedstawiono tr贸jparametrowy model czasu zdatno艣ci systemu technicznego nara偶onego na dwa typy zagro偶e艅. Do pierwszego typu zagro偶e艅 nale偶膮 wszelkie zagro偶enia incydentalne, a do drugiego tak zwane zagro偶enia starzeniowe. Motywacj膮 do napisania tej pracy by艂a w艂a艣nie idea po艂膮czenia bada艅 tych dw贸ch typ贸w zagro偶e艅, z jakimi mamy cz臋sto do czynienia w praktyce, zw艂aszcza w kontek艣cie system贸w technicznych. Celem pracy jest wskazanie alternatywy dla masowo stosowanego rozk艂adu Weibulla w badaniu czas贸w zdatno艣ci system贸w. W punkcie 1 opisano tr贸jparametrowy model, zdefiniowany jako minimum dw贸ch zmiennych losowych. Uzasadniono zar贸wno potrzeb臋 wprowadzenia tego modelu, jak i jego przewag臋 nad dotychczasowym sposobem modelowania czasu zdatno艣ci systemu. W punkcie 2 przedstawiono podstawowe charakterystyki funkcyjne i liczbowe wprowadzonego modelu zdatno艣ci systemu. Ponadto obliczono wp艂yw parametr贸w, dla r贸偶nych kombinacji ich warto艣ci, na ustalenie przyczyny utraty zdatno艣ci systemu.In constructing a lifetime model of any technical system, sometimes the traditionally used Weibull distribution is biased. In consequence, parameter estimation can be fatal. In this situation, it is not possible to find a good fitting function that characterises the system lifetime. Here all possible risks of the system are divided into two types: accidental and ageing risks. The accidental risk has an exponential distribution, and the ageing risk has a Weibull distribution. In this paper, a three parameters model of the system lifetime with both types of risks is presented. Modelling was performed by a simple competing risk distribution as a possible alternative to the Weibull distribution in lifetime analysis. This distribution corresponds to the minimum between the family of exponential and family of Weibull distributions. Our motivation was to take account of both accidental and ageing risks in lifetime data analysis. For this purpose, we introduced a three-parameter model, where such functions as hazard function, survival function, and density function are presented. Then, such characteristics as the expected value and variance of the modelled system lifetime are considered. Finally, the problem of choosing between an exponential, Weibull, or the introduced competing risk model is discussed
Survival function of the sequence of risks and its approximation
W teorii niezawodno艣ci podstawowym zagadnieniem jest wyznaczenie funkcji przetrwania dla eksploatowanych obiekt贸w, kt贸re s膮 ci膮gle nara偶one na utrat臋 zdatno艣ci ze wzgl臋du na r贸偶norakie zagro偶enia. Przedstawione w tej pracy metody mo偶na zastosowa膰 do klasy obiekt贸w, kt贸re s膮 zdolne odparowa膰 zagro偶enie i to wielokrotnie zanim utrac膮 zdatno艣膰. Przyjmujemy, 偶e zagro偶enia systemu mog膮 si臋 powtarza膰, wi臋c mo偶emy m贸wi膰 o strumieniach zagro偶e艅. Rozwa偶amy zagadnienie aproksymacji rozk艂adu prawdopodobie艅stwa w oparciu o funkcj臋 przetrwania obiektu technicznego nara偶onego na losowy strumie艅 zagro偶e艅. Wprowadzamy og贸ln膮 posta膰 funkcji przetrwania zagro偶e艅 jak i dwa szczeg贸艂owe modele: Poissonowski i dwumianowy. W okresie eksploatacji obiektu cz臋sto trudno jest okre艣li膰 jego czas zdatno艣ci, wi臋c przedstawiamy aproksymacj臋 funkcji przetrwania i szacujemy b艂膮d tej aproksymacji.In the theory of reliability, a basic topic is determining the survival function of exploited objects. We assume that these objects are constantly exposed to the loss of ability because of various dangers. Methods presented in this publication can be applied to an object that is able to repel the danger many times before it loses its usefulness. We suppose that the danger to the system can repeat many times, which is "the sequence of risks." The technical object is exposed to a random sequence of risks, and we consider the problem of the approximation of the lifetime probability distribution based on the survival function. We introduce a general form of the survival function in the context of a sequence of risks and two particular models: the Poisson and binomial model. In the time of exploitation the object, it is very difficult to find the lifetime distribution, so we introduce an approximation of the survival function, and we estimate the error of this approximation. It can be very useful in practice
Genetic technology transfer to Kenyan agriculture in the context of biotechnology research
Poissonowskie strumienie uszkodze艅 w prognozowaniu koszt贸w obs艂ug korekcyjnych floty pojazd贸w
Maintaining high efficiency of using the fleet of public mass transport vehicles puts many challenges ahead of the operator. Among them, when planning periodic operational activities, the operator should take into account the assessment of possible unexpected vehicle failures and the costs of their removal under the so-called corrective maintenance. Due to the random nature of vehicle breakdowns, knowledge about stochastic processes is necessary to maintain their efficient and safe operation. The research problem formulated in the title meets these needs. Therefore, the costs of corrective maintenance of vehicles are modelled, i.e. the costs that are not included in the scheduled maintenance costs and are not related to preventive maintenance. The costs of corrective maintenance and the costs of replacement of damaged parts are unexpectedly created at random moments of operating means of transport, usually between scheduled maintenance. Due to the variety of failure processes of individual parts of the vehicle, the methods and applications of stochastic modelling for simple failures modelled by the Poisson process are presented in this paper. The basis for the application of the presented methods is to identify those parts of the vehicle that are damaged in accordance with this process. The assessment of parameters of failure processes of individual vehicle parts is made on the basis of the operational database of a homogeneous fleet of vehicles operated for 5 years. The operational database is dynamically updated with new events. On the basis of actual data on corrective maintenance of a distinguished group of damaged parts of vehicles, the possibilities and limitations of practical applications of the Poisson process to assess the risk of incurring costs in the further process of fleet operation were shown.Utrzymanie wysokiej efektywno艣ci u偶ytkowania floty pojazd贸w publicznego transportu masowego stawia przed operatorem wiele wyzwa艅. W艣r贸d nich planuj膮c okresowe dzia艂ania eksploatacyjne operator powinien uwzgl臋dnia膰 oceny mo偶liwo艣ci pojawiania si臋 niespodziewanych awarii pojazd贸w oraz koszt贸w ich usuwania w ramach tak zwanych obs艂ug korekcyjnych. Ze wzgl臋du na losowy charakter awarii pojazd贸w dla utrzymania efektywnej i bezpiecznej ich eksploatacji niezb臋dna okazuje si臋 wiedza dotycz膮ca proces贸w stochastycznych. Sformu艂owany w tytule problem badawczy wychodzi naprzeciw tym potrzebom. Modelowane s膮 wi臋c koszty obs艂ug korekcyjnych pojazd贸w, tj. koszty, kt贸re nie s膮 uwzgl臋dniane w ich przegl膮dach planowych i nie obci膮偶aj膮 prewencyjnych napraw. Koszty rob贸t korekcyjnych i koszty wymiany uszkodzonych cz臋艣ci powstaj膮 niespodziewanie w losowych chwilach u偶ytkowania 艣rodk贸w transportu, zwykle mi臋dzy okresowymi przegl膮dami. W niniejszej pracy, ze wzgl臋du na r贸偶norodno艣膰 proces贸w uszkadzania poszczeg贸lnych cz臋艣ci pojazdu, przedstawiono metody i zastosowania stochastycznego modelowania dla prostych strumieni uszkodze艅, kt贸rych modelem jest proces Poissona. Podstaw膮 zastosowania przedstawionych metod jest zidentyfikowanie tych cz臋艣ci pojazdu, kt贸re uszkadzaj膮 si臋 zgodnie z tym procesem. Oceny parametr贸w proces贸w uszkodze艅 poszczeg贸lnych cz臋艣ci pojazd贸w dokonywane s膮 na podstawie bazy danych eksploatacyjnych jednorodnej floty pojazd贸w eksploatowanych przez 5 lat. Wraz z up艂ywem czasu baza danych eksploatacyjnych jest dynamicznie uzupe艂niana o nowe zdarzenia. Na podstawie danych rzeczywistych o obs艂ugach korekcyjnych wyr贸偶nionej grupy uszkadzaj膮cych si臋 cz臋艣ci pojazd贸w pokazano mo偶liwo艣ci i ograniczenia praktycznych zastosowa艅 procesu Poissona do oceny ryzyka poniesienia koszt贸w w dalszym procesie eksploatacji floty
Carbon monoxide and nitric oxide concentrations in the flue gas during the combustion of agricultural biomass briquettes in a 25 kW log gasification boiler
Clinical anatomy of the auriculotemporal nerve in area of infratemporal fossa
The auriculotemporal nerve is a sensory branch extending from the posterior section of the mandibular nerve trunk. Its nerve roots form a short trunk, which gives off a number of branches, innervating: the temporomandibular joint, the temporal region, structures of the external ear: auricle, and external acoustic meatus and parotid gland. It also conducts excretory fibres to the buccal and labial glands. Anatomical relationships between the auriculotemporal nerve and the muscles of mastication, temporomandibular joint, and surrounding vessels in the area of infratemporal fossa create favourable conditions for entrapment syndromes. Entrapment of the auriculotemporal nerve plays a role in the pathogenesis of temporomandibular joint pain syndromes, headaches, as well as pain symptoms or paresthesias within the external acoustic meatus and auricle. The current study was performed on 16 specimens containing the infratemporal fossa. Some variations in the nerve roots of the auriculotemporal nerve was found and described as one-, two-, three-, four-, and five- root variants. The topography of the auriculotemporal nerve and its close relationship to structures of the temporomandibular joint were described. Individually, variable topography of the nerve course may play a role in symptomatology of headaches and localization of pain in the face regions and masticatory system