Number of results to display per page
Search Results
478282. Two types of high inductive electromagnetic stimulation and their different effects on endothelial cells
- Creator:
- Průcha, J. , Skopalik, J. , Socha, V., Hanáková, L., Knopfová, L. , and Hána, K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- low frequency-electromagnetic fields, induced electric currents, neoangiogenesis, and endothelial cells
- Language:
- English
- Description:
- Effects of low-frequency electromagnetic fields (LF EMF) on the activation of different tissue recovery processes have not yet been fully understood. The detailed quantification of LF EMF effects on the angiogenesis were analysed in our experiments by using cultured human and mouse endothelial cells. Two types of fields were used in the tests as follows: the LF EMF with rectangular pulses, 340-microsecond mode at a frequency of 72 Hz and peak intensity 4 mT, and the LF EMF with sinusoidal alternating waveform 5 000 Hz, amplitude-modulated by means of a special interference spectrum mode set to a frequency linear sweep from 1 to 100 Hz for 6 s and from 100 Hz to 1 Hz return also for 6 s, swing period of 12 second. Basic parameters of cultured cells measured after the LF EMF stimulus were viability and proliferation acceleration. Both types of endothelial cells (mouse and human ones) displayed significant changes in the proliferation after the application of the LF EMF under conditions of a rectangular pulse mode. Based on the results, another test of the stimulation on a more complex endothelial-fibroblast coculture model will be the future step of the investigation.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
478283. Two types of refuge have opposite effects on the size of larval aggregations in a tropical defoliator
- Creator:
- Horgan, Finbarr G.
- Type:
- article, model:article, and TEXT
- Subject:
- Defence, density responses, El Salvador, Ficus, gregariousness, parasitism, refuges, Tachinidae, tiger moth, and tropical defoliator
- Language:
- English
- Description:
- Many gregarious insects aggregate in naturally occurring refuges on their host plants. However, when refuges are filled, they may be forced to aggregate on exposed areas of the plant. This study examines the effects of refuge saturation on group size and defence against parasitism in larvae of Ammalo helops Cramer (Lepidoptera: Arctiidae) that form day-resting groups on the trunks of weeping laurel, Ficus benjamina L., in El Salvador. Population densities, group sizes and parasitism were recorded on eight trees for each of four generations in 1995 and 1996. When population densities were low, all larvae were located in small groups in naturally occurring structural refuges (rotted out holes, spaces between crossing branches and under aerial roots) on the host plant. In contrast, when population densities were high and structural refuges were full, many larvae formed significantly larger groups (density refuges) on the open trunk. Between 20 and 24% of late-instar larvae were parasitized and this was inversely dependent on the size of within tree populations, in spite of populations being fragmented among structural refuges. Similarly, in a study carried out at a different location on young trees without structural refuges, parasitism of larvae was inversely related to group size. Although parasitism rates decreased with increasing group size, most larvae preferentially selected the small naturally occurring refuges, where groups were restricted to low densities. If this behaviour is an adaptive trait, I speculate that parasitism (or some other unmeasured mortality factor) is lower in naturally occurring refuges than in large open groups.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
478284. Two valued measure and some new double sequence spaces in $2$-normed spaces
- Creator:
- Das, Pratulananda, Savas, Ekrem, and Bhunia, Santanu
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- convergence, $\mu $-statistical convergence, convergence in $\mu $-density, condition (APO$_{2}$), 2-norm, 2-normed space, paranorm, paranormed space, Orlicz function, and sequence space
- Language:
- English
- Description:
- The purpose of this paper is to introduce some new generalized double difference sequence spaces using summability with respect to a two valued measure and an Orlicz function in $2$-normed spaces which have unique non-linear structure and to examine some of their properties. This approach has not been used in any context before.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
478285. Two valued measure and summability of double sequences
- Creator:
- Das, Pratulananda and Bhunia, Santanu
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- double sequences, $\mu $-statistical convergence, divergence and Cauchy criteria, convergence, divergence and Cauchy criteria in $\mu $-density, and condition (APO$_2)$
- Language:
- English
- Description:
- In this paper, following the methods of Connor \cite {connor}, we extend the idea of statistical convergence of a double sequence (studied by Muresaleen and Edely \cite {moe}) to $\mu $-statistical convergence and convergence in $\mu $-density using a two valued measure $\mu $. We also apply the same methods to extend the ideas of divergence and Cauchy criteria for double sequences. We then introduce a property of the measure $\mu $ called the (APO$_2$) condition, inspired by the (APO) condition of Connor \cite {jc}. We mainly investigate the interrelationships between the two types of convergence, divergence and Cauchy criteria and ultimately show that they become equivalent if and only if the measure $\mu $ has the condition (APO$_2$).
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
478286. Two wavelenght picosecond ranging of ground target
- Creator:
- Hamal, K., Prochazka, I., and Gaignebet, J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- scientific research, two wavelenght experiment, and Nd YAG laser
- Language:
- Czech
- Description:
- One of the limiting factors in decreasing the systematic error of laser ranging is the influence of the atmospheric refraction. Two colour ranging may contribute useful information for more precise refraction factor modelling and calculation. We will describe two wavelength experiment using streak camera as a high resolution detector for ground target distance measurement.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
478287. Two ways of finding a host: A specialist and a generalist parasitoid species (Hymenoptera: Chalcidoidea: Pteromalidae)
- Creator:
- Peters, Ralph S.
- Type:
- article, články, model:article, and TEXT
- Subject:
- Zoologie, entomologie, Hymenoptera, Chalcidoidea, Pteromalidae, Nasonia vitripennis, Dibrachys microgastri, parasitic wasps, specialist, generalist, locomotor activity, laboratory experiments, parasitoid life history traits, host finding, olfactory cues, 2, and 59
- Language:
- English
- Description:
- Two closely related parasitoid wasp species with different host specificities were used for experimental studies on the biology of host finding, a crucial element of parasitoid life history: The habitat and host specialist Nasonia vitripennis and the habitat and host generalist Dibrachys microgastri (Chalcidoidea: Pteromalidae). The host finding parameters tested included reaction to olfactory cues, aspects of locomotor activity, ability to locate hidden hosts and day-night-activity. The results revealed distinct interspecific differences that match the respective host and habitat ranges of the two species. In N. vitripennis host finding is dominated by olfactory reaction to hosts and host habitat, i.e., fly puparia and birds' nests. In D. microgastri olfactory cues have only a minor role. Its host finding is characterized by rapid searching at random. Both species are able to locate hidden hosts. Although still incomplete, these insights into host finding by two parasitoid species with different life history strategies indicate they can be characterized by specific combinations of behavioural host finding features. and Ralph S. Peters.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
478288. Two weak points of the enhanced Indispensability argument - domain of the argument and definition of indispensability
- Creator:
- Drekalović, Vladimir
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Platonism, enhanced indispensability argument, definition of indispensability, and intuition
- Language:
- Slovak
- Description:
- The contemporary Platonists in the philosophy of mathematics argue that mathematical objects exist. One of the arguments by which they support this standpoint is the so-called Enhanced Indispensability Argument (EIA). This paper aims at pointing out the difficulties inherent to the EIA. The first is contained in the vague formulation of the Argument, which is the reason why not even an approximate scope of the set objects whose existence is stated by the Argument can be established. The second problem is reflected in the vagueness of the very term indispensability, which is essential to the Argument. The paper will remind of a recent definition of the concept of indispensability of a mathematical object, reveal its deficiency and propose an improvement of this definition. Following this, we will deal with one of the consequences of the arbitrary employment of the concept of indispensability of a mathematical theory. We will propose a definition of this concept as well, in accordance with the common intuition about it. Eventually, on the basis of these two definitions, the paper will describe the relation between these two concepts, in the attempt to clarify the conceptual apparatus of the EIA., Současní platonisté ve filozofii matematiky argumentují, že matematické objekty existují. Jedním z argumentů, které toto stanovisko podporují, je tzv. Enhanced Indispensability Argument (EIA). Cílem tohoto příspěvku je poukázat na obtíže spojené s EIA. První z nich je obsažena v vágní formulaci Argumentu, což je důvod, proč nelze stanovit ani přibližný rozsah nastavených objektů, jejichž existence je uvedena argumentem. Druhý problém se odráží v neurčitosti samotného pojmu nepostradatelnost, která je pro argument nezbytná. Příspěvek bude připomínat nedávnou definici pojmu nepostradatelnost matematického objektu, odhalit jeho nedostatek a navrhnout zlepšení této definice. Poté budeme se zabývat jedním z důsledků svévolného zaměstnávání konceptu nepostradatelnosti matematické teorie. Navrhneme také definici této koncepce v souladu se společnou intuicí. Nakonec, na základě těchto dvou definic, bude článek popsat vztah mezi těmito dvěma pojmy, ve snaze objasnit koncepční aparát EIA., and Vladimir Drekalović
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
478289. Two-fold theorem on Fréchetness of products
- Creator:
- Dolecki, Szymon and Nogura, Tsugunori
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- $\alpha_3$, $\alpha_4$, $\beta_3$, $\beta_4$, 4$ spaces, $\Phi$-space, product space, sequential space, sequentially subtransverse, strongly Fréchet, and transverse
- Language:
- English
- Description:
- A refined common generalization of known theorems (Arhangel’skii, Michael, Popov and Rančin) on the Fréchetness of products is proved. A new characterization, in terms of products, of strongly Fréchet topologies is provided.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
478290. Two-stage model selection with parameters weighted hidden Markov models and likelihood ratio for part-of-speech tagging
- Creator:
- Sun, Schichang, Liu, Hongbo, Zhao, Pixo , and Lin, Hongfei
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Hidden Markov models, model selection, part-of speech tagging, and likehood ration
- Language:
- English
- Description:
- In many natural language processing applications two or more models usually have to be involved for accuracy. But it is difficult for minor models, such as “backoff” taggers in part-of-speech tagging, to cooperate smoothly with the major probabilistic model. We introduce a two-stage approach for model selection between hidden Markov models and other minor models. In the first stage, the major model is extended to give a set of candidates for model selection. Parameters weighted hidden Markov model is presented using weighted ratio to create the candidate set. In the second stage, heuristic rules and features are used as evaluation functions to give extra scores to candidates in the set. Such scores are calculated using a diagnostic likelihood ratio test based on sensitivity and specificity criteria. The selection procedure can be fulfilled using swarm optimization technique. Experiment results on public tagging data sets show the applicability of the proposed approach.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public