988 resultados para Propagation characteristics


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Political actors use ICTs in a different manner and in different degrees when it comes to achieving a closer relationship between the public and politicians. Usually, political parties develop ICT strategies only for electoral campaigning and therefore restrain ICT usages to providing information and establishing a few channels of communication. By contrast, local governments make much more use of ICT tools for participatory and deliberative purposes. These differences in usages have not been well explained in the literature because of a lack of a comprehensive explanatory model. This chapter seeks to build the basis for this model, that is, to establish which factors affect and condition different political uses of ICTs and which principles underlie that behaviour. We consider that political actors are intentional and their behaviour is mediated by the political institutions and the socioeconomic context of the country. Also, though, the actor¿s own characteristics, such as the type and size of the organization or the model of e-democracy that the actor upholds, can have an influence in launching ICT initiatives for approaching the public.

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The knowledge on the optics of fogbows is scarce, and their polarization characteristics have never been measured to our knowledge. To fill this gap we measured the polarization features of 16 fogbows during the Beringia 2005 Arctic polar research expedition by imaging polarimetry in the red, green and blue spectral ranges. We present here the first polarization patterns of the fogbow. In the patterns of the degree of linear polarization p, fogbows and their supernumerary bows are best visible in the red spectral range due to the least dilution of fogbow light by light scattered in air. In the patterns of the angle of polarization α fogbows are practically not discernible because their α-pattern is the same as that of the sky: the direction of polarization is perpendicular to the plane of scattering and is parallel to the arc of the bow, independently of the wavelength. Fogbows and their supernumeraries were best seen in the patterns of the polarized radiance. In these patterns the angular distance δ between the peaks of the primary and the first supernumerary and the angular width σ of the primary bow were determined along different radii from the center of the bow. δ ranged between 6.08° and 13.41° , while σ changed from 5.25° to 19.47° . Certain fogbows were relatively homogeneous, meaning small variations of δ and σ along their bows. Other fogbows were heterogeneous, possessing quite variable δ- and σ-values along their bows. This variability could be a consequence of the characteristics of the high Arctic with open waters within the ice shield resulting in the spatiotemporal change of the droplet size within the fog

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In the thesis the principle of work of eddy current position sensors and the main cautions that must be taken into account while sensor design process are explained. A way of automated eddy current position sensor electrical characteristics measurement is suggested. A prototype of the eddy current position sensor and its electrical characteristics are investigated. The results obtained by means of the automated measuring system are explained.

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The aim of this investigation was to analyze the dental occlusion in the deciduous dentition, and the effects of orthodontic treatment carried out in the early mixed dentition with the eruption guidance appliance. The deciduous occlusion and craniofacial morphology of 486 children (244 girls and 242 boys) were investigated at the onset of the mixed dentition period (mean age 5.1 years, range 4.0-7.8 years). Treatment in the treatment group and follow-up in the control group were started when the first deciduous incisor was exfoliated (T1) and ended when all permanent incisors and first molars were fully erupted (T2). The mean age of the children was 5.1 years (SD 0.5) at T1 and 8.4 years (SD 0.5) at T2. Treatment was carried out with the eruption guidance appliance. Occlusal changes that took place in 167 children were compared with those of 104 untreated control children. Pre- and post-treatment cephalometric radiographs were taken, and the craniofacial morphology of 115 consecutively treated children was compared with that of 104 control children. The prevalence of malocclusion in the deciduous dentition was 68% or 93% depending on how the cut-off value between the acceptable and non-acceptable occlusal characteristic was defined. The early dentofacial features of children with distal occlusion, large overjet and deepbite differed from those with normal occlusion. However, the skeletal pattern of these three malocclusions showed considerable similarity each being characterized by a retrusive mandible, small maxillo-mandibular difference, convex profile, retrusive lower incisors, and large interincisal angle. In the treatment group, overjet and overbite decreased significantly from T1 to T2. Following treatment, a tooth-to-tooth contact was found in 99% of the treated children but only in 24% of the controls. A Class I molar relationship was observed in 90% of the children in the treatment group, and in 48% in the control group. Good alignment of the incisors was observed in 98% of the treated children, whereas upper crowding was found in 32% and lower crowding in 47% of the controls. A significant difference between the groups was found in the mandibular length, midfacial length and maxillo-mandibular differential. The occlusal correction, brought about by the eruption guidance appliance, was achieved mainly through changes in the dentoalveolar region of the mandible. In addition, the appliance seemed to enhance the growth of the mandible. Treatment in the early mixed dentition using the eruption guidance appliance is an effective method to normalize occlusion and reduce further need of orthodontic treatment. Only few spontaneous corrective changes can be expected without active intervention.

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The purpose of this comparative study is to profile second language learners by exploring the factors which have an impact on their learning. The subjects come from two different countries: one group comes from Milwaukee, US, and the other from Turku, Finland. The subjects have attended bilingual classes from elementary school to senior high school in their respective countries. In the United States, the subjects (N = 57) started in one elementary school from where they moved on to two high schools in the district. The Finnish subjects (N = 39) attended the same school from elementary to high school. The longitudinal study was conducted during 1994-2004 and combines both qualitative and quantitative research methods. A Pilot Study carried out in 1990-1991 preceded the two subsequent studies that form the core material of this research. The theoretical part of the study focuses first on language policies in the United States and Finland: special emphasis is given to the history, development and current state of bilingual education, and the factors that have affected policy-making in the provision of language instruction. Current language learning theories and models form the theoretical foundation of the research, and underpin the empirical studies. Cognitively-labeled theories are at the forefront, but sociocultural theory and the ecological approach are also accounted for. The research methods consist of questionnaires, compositions and interviews. A combination of statistical methods as well as content analysis were used in the analysis. The attitude of the bilingual learners toward L1 and L2 was generally positive: the subjects enjoyed learning through two languages and were motivated to learn both. The knowledge of L1 and parental support, along with early literacy in L1, facilitated the learning of L2. This was particularly evident in the American subject group. The American subjects’ L2 learning was affected by the attitudes of the learners to the L1 culture and its speakers. Furthermore, the negative attitudes taken by L1 speakers toward L2 speakers and the lack of opportunities to engage in activities in the L1 culture affected the American subjects’ learning of L2, English. The research showed that many American L2 learners were isolated from the L1 culture and were even afraid to use English in everyday communication situations. In light of the research results, a politically neutral linguistic environment, which the Finnish subjects inhabited, was seen to be more favorable for learning. The Finnish subjects were learning L2, English, in a neutral zone where their own attitudes and motivation dictated their learning. The role of L2 as a means of international communication in Finland, as opposed to a means of exercising linguistic power, provided a neutral atmosphere for learning English. In both the American and Finnish groups, the learning of other languages was facilitated when the learner had a good foundation in their L1, and the learning of L1 and L2 were in balance. Learning was also fostered when the learners drew positive experiences from their surroundings and were provided with opportunities to engage in activities where L2 was used.

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Several models for the estimation of thermodynamic properties of layered double hydroxides (LDHs) are presented. The predicted thermodynamic quantities calculated by the proposed models agree with experimental thermodynamic data. A thermodynamic study of the anion exchange process on LDHs is also made using the described models. Tables for the prediction of monovalent anion exchange selectivities on LDHs are provided. Reasonable agreement is found between the predicted and the experimental monovalent anion exchange selectivities.

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Many Ophidiidae are active in dark environments and display complex sonic apparatus morphologies. However, sound recordings are scarce and little is known about acoustic communication in this family. This paper focuses on Ophidion rochei which is known to display an important sexual dimorphism in swimbladder and anterior skeleton. The aims of this study were to compare the sound producing morphology, and the resulting sounds in juveniles, females and males of O. rochei.Results: Males, females, and juveniles possessed different morphotypes. Females and juveniles contrasted with males because they possessed dramatic differences in morphology of their sonic muscles, swimbladder, supraoccipital crest, and first vertebrae and associated ribs. Further, they lacked the ‘rocker bone’ typically found in males. Sounds from each morphotype were highly divergent. Males generally produced non harmonic, multiple-pulsed sounds that lasted for several seconds (3.5 ± 1.3 s) with a pulse period of ca. 100 ms. Juvenile and female sounds were recorded for the first time in ophidiids. Female sounds were harmonic, had shorter pulse period (±3.7 ms), and never exceeded a few dozen milliseconds (18 ± 11 ms). Moreover, unlike male sounds, female sounds did not have alternating long and short pulse periods. Juvenile sounds were weaker but appear to be similar to female sounds.Conclusions: Although it is not possible to distinguish externally male from female in O. rochei, they show a sonic apparatus and sounds that are dramatically different. This difference is likely due to their nocturnal habits that may have favored the evolution of internal secondary sexual characters that help to distinguish males from females and that could facilitate mate choice by females. Moreover, the comparison of different morphotypes in this study shows that these morphological differences result from a peramorphosis that takes place during the development of the gonads

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Molecular Characteristics of Neuroblastoma with Special Reference to Novel Prognostic Factors and Diagnostic Applications Department of Medical Biochemistry and Genetics Annales Universitatis Turkuensis, Medica-Odontologica, 2009, Turku, Finland Painosalama Oy, Turku, Finland 2009 Background: Neuroblastoma, which is the most common and extensively studied childhood solid cancer, shows a great clinical and biological heterogeneity. Most of the neuroblastoma patients older than one year have poor prognosis despite intensive therapies. The hallmark of neuroblastoma, biological heterogeneity, has hindered the discovery of prognostic tumour markers. At present, few molecular markers, such as MYCN oncogene status, have been adopted into clinical practice. Aims: The aim of the study was to improve the current prognostic methodology of neuroblastoma, especially by taking cognizance of the biological heterogeneity of neuroblastoma. Furthermore, unravelling novel molecular characteristics which associate with neuroblastoma tumour progression and cell differentiation was an additional objective. Results: A new strictly defined selection of neuroblastoma tumour spots of highest proliferation activity, hotspots, appeared to be representative and reliable in an analysis of MYCN amplification status using a chromogenic in situ hybridization technique (CISH). Based on the hotspot tumour tissue microarray immunohistochemistry and high-resolution oligo-array-based comparative genomic hybridization, which was integrated with gene expression and in silico analysis of existing transcriptomics, a polysialylated neural cell adhesion molecule (NCAM) and poorly characterized amplicon at 12q24.31 were discovered to associate with outcome. In addition, we found that a previously considered new neuroblastoma treatment target, the mutated c-kit receptor, was not mutated in neuroblastoma samples. Conclusions: Our studies indicate polysialylated NCAM and 12q24.31 amplicon to be new molecular markers with important value in prognostic evaluation of neuroblastoma. Moreover, the presented hotspot tumour tissue microarray method together with the CISH technique of the MYCN oncogene copy number is directly applicable to clinical use. Key words: neuroblastoma, polysialic acid, neural cell adhesion molecule, MYCN, c-kit, chromogenic in situ hybridization, hotspot

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A damage model for the simulation of delamination propagation under high-cycle fatigue loading is proposed. The basis for the formulation is a cohesive law that links fracture and damage mechanics to establish the evolution of the damage variable in terms of the crack growth rate dA/dN. The damage state is obtained as a function of the loading conditions as well as the experimentally-determined coefficients of the Paris Law crack propagation rates for the material. It is shown that by using the constitutive fatigue damage model in a structural analysis, experimental results can be reproduced without the need of additional model-specific curve-fitting parameters

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The effect of pork fat reduction (from 44% to 20% final fat content) and its partial substitution by sunflower oil (3% addition) on the physicochemical, instrumental and sensory properties throughout storage time of small caliber non-acid fermented sausages (fuet type) with reduced sodium content (with partial substitution of NaCl by KCl and K-lactate) and without direct addition of nitrate and nitrite (natural nitrate source used instead), was studied. Results showed that sausages with reduced fat (10% initial fat content) and with acceptable sensory characteristics can be obtained by adding to the shoulder lean (8% fat content) during the grinding, either 3.3% backfat (3% fat content) or 3% sunflower oil, both previously finely comminuted with lean. Furthermore, sunflower oil showed to be suitable for partial pork backfat substitution in very lean fermented sausages, conferring desirable sensory properties similar to those of sausages with standard fat content. The sensory quality of the sausages was maintained after three-month cold storage in modified atmosphere.

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It is shown that Lotka-Volterra interaction terms are not appropriate to describe vertical cultural transmission. Appropriate interaction terms are derived and used to compute the effect of vertical cultural transmission on demic front propagation. They are also applied to a specific example, the Neolithic transition in Europe. In this example, it is found that the effect of vertical cultural transmission can be important (about 30%). On the other hand, simple models based on differential equations can lead to large errors (above 50%). Further physical, biophysical, and cross-disciplinary applications are outlined

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Tässä työssä toteutetaan IEEE 802.16-2004 standardiin perustuva langaton WiMAX tietoliikenneverkko, sekä tutkitaan etenemismallien soveltuvuutta satama-alueelle. Myös muiden verkkoratkaisujen soveltuvuutta pohditaan. Lisäksi tutkitaan sääolosuhteiden sekä päätelaitteen liikkumisnopeuden vaikutuksia yhteyteen. Satama-alueella on teräksestä valmistettuja merikontteja pinottuina päällekkäin, ja ne vaikeuttavat langattomien signaalien etenemistä. Merikonttien pinot säilyttävät tietyn maksimikorkeuden johtuen työkoneiden rajallisesta kyvystä pinota niitä. Langattomien signaalien etenemiselle erilaisissa ympäristöissä on kehitetty etenemismalleja. Etenemisallien avulla voidaan pyrkiä ennustamaan signaalin vahvuutta eri etäisyyksillä tukiasemasta. Etenemismallit kuvaavat ympäristön aiheuttamaa signaalin vaimenemista erilaisten muuttujien avulla. Langattoman tietoliikenneverkon toteutus ongelmatilanteineen dokumentoitiin ja alueella tehtiin kuuluvuusmittauksia. Löydettiin etenemismalli ja muuttujat, joiden avulla lasketut tulokset vastasivat mitattuja tuloksia hyvin. Myös sääolosuhteiden sekä päätelaitteen liikkumisnopeuden vaikutusta signaalin vahvuuteen tutkittiin. Vesi- ja lumisateen sekä sumun vaikutuksen todettiin olevan merkityksetön verkon käyttämällä 3.5 GHz taajuusalueella. Myöskään päätelaitteen liikkumisnopeuden ei todettu vaikuttavan toiminnallisuuteen 20-30 kilometrin tuntinopeudella, jolla työkoneet alueella liikkuvat.

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Cooling crystallization is one of the most important purification and separation techniques in the chemical and pharmaceutical industry. The product of the cooling crystallization process is always a suspension that contains both the mother liquor and the product crystals, and therefore the first process step following crystallization is usually solid-liquid separation. The properties of the produced crystals, such as their size and shape, can be affected by modifying the conditions during the crystallization process. The filtration characteristics of solid/liquid suspensions, on the other hand, are strongly influenced by the particle properties, as well as the properties of the liquid phase. It is thus obvious that the effect of the changes made to the crystallization parameters can also be seen in the course of the filtration process. Although the relationship between crystallization and filtration is widely recognized, the number of publications where these unit operations have been considered in the same context seems to be surprisingly small. This thesis explores the influence of different crystallization parameters in an unseeded batch cooling crystallization process on the external appearance of the product crystals and on the pressure filtration characteristics of the obtained product suspensions. Crystallization experiments are performed by crystallizing sulphathiazole (C9H9N3O2S2), which is a wellknown antibiotic agent, from different mixtures of water and n-propanol in an unseeded batch crystallizer. The different crystallization parameters that are studied are the composition of the solvent, the cooling rate during the crystallization experiments carried out by using a constant cooling rate throughout the whole batch, the cooling profile, as well as the mixing intensity during the batch. The obtained crystals are characterized by using an automated image analyzer and the crystals are separated from the solvent through constant pressure batch filtration experiments. Separation characteristics of the suspensions are described by means of average specific cake resistance and average filter cake porosity, and the compressibilities of the cakes are also determined. The results show that fairly large differences can be observed between the size and shape of the crystals, and it is also shown experimentally that the changes in the crystal size and shape have a direct impact on the pressure filtration characteristics of the crystal suspensions. The experimental results are utilized to create a procedure that can be used for estimating the filtration characteristics of solid-liquid suspensions according to the particle size and shape data obtained by image analysis. Multilinear partial least squares regression (N-PLS) models are created between the filtration parameters and the particle size and shape data, and the results presented in this thesis show that relatively obvious correlations can be detected with the obtained models.

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The microbiological bioassay, UV-spectrophotometry and HPLC methods for assaying gatifloxacin in tablets were compared. Validation parameters such as linearity, precision, accuracy, limit of detection and limit of quantitation were determined. Beer's law was obeyed in the ranges 4.0-14.0 μg/mL for HPLC and UV-spectrophotometric method, and 4.0-16.0 μg/mL for bioassay. All methods were reliable within acceptable limits for antibiotic pharmaceutical preparations being accurate, precise and reproducible. The bioassay and HPLC are more specific than UV-spectrophotometric analysis. The application of each method as a routine analysis should be investigated considering cost, simplicity, equipment, solvents, speed, and application to large or small workloads.

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Systemic lupus erythematosus (SLE) predominantly affects young women in their 20s. In 40 out of 250 (16%) patients with SLE seen in our hospital disease onset occurred after the age of 50. The interval between the time of onset and diagnosis was five years in this older group compared with three years in the younger group. Arthritis, as a first symptom, was less common in the older onset group. During the follow up a lower incidence of arthritis, malar rash, photosensitivity, and nephropathy was found in the older onset group. In contrast, this group showed an increased incidence of myositis. High titres of anti-dsDNA tended to occur less often and the incidence of anti-Ro antibodies was lower in the older onset group. These features seem to distinguish patients with older onset SLE as a particular subset.