13 resultados para adventitious streams

em Helda - Digital Repository of University of Helsinki


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The auditory system can detect occasional changes (deviants) in acoustic regularities without the need for subjects to focus their attention on the sound material. Deviant detection is reflected in the elicitation of the mismatch negativity component (MMN) of the event-related potentials. In the studies presented in this thesis, the MMN is used to investigate the auditory abilities for detecting similarities and regularities in sound streams. To investigate the limits of these processes, professional musicians have been tested in some of the studies. The results show that auditory grouping is already more advanced in musicians than in nonmusicians and that the auditory system of musicians can, unlike that of nonmusicians, detect a numerical regularity of always four tones in a series. These results suggest that sensory auditory processing in musicians is not only a fine tuning of universal abilities, but is also qualitatively more advanced than in nonmusicians. In addition, the relationship between the auditory change-detection function and perception is examined. It is shown that, contrary to the generally accepted view, MMN elicitation does not necessarily correlate with perception. The outcome of the auditory change-detection function can be implicit and the implicit knowledge of the sound structure can, after training, be utilized for behaviorally correct intuitive sound detection. These results illustrate the automatic character of the sensory change detection function.

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This thesis examines brain networks involved in auditory attention and auditory working memory using measures of task performance, brain activity, and neuroanatomical connectivity. Auditory orienting and maintenance of attention were compared with visual orienting and maintenance of attention, and top-down controlled attention was compared to bottom-up triggered attention in audition. Moreover, the effects of cognitive load on performance and brain activity were studied using an auditory working memory task. Corbetta and Shulman s (2002) model of visual attention suggests that what is known as the dorsal attention system (intraparietal sulcus/superior parietal lobule, IPS/SPL and frontal eye field, FEF) is involved in the control of top-down controlled attention, whereas what is known as the ventral attention system (temporo-parietal junction, TPJ and areas of the inferior/middle frontal gyrus, IFG/MFG) is involved in bottom-up triggered attention. The present results show that top-down controlled auditory attention also activates IPS/SPL and FEF. Furthermore, in audition, TPJ and IFG/MFG were activated not only by bottom-up triggered attention, but also by top-down controlled attention. In addition, the posterior cerebellum and thalamus were activated by top-down controlled attention shifts and the ventromedial prefrontal cortex (VMPFC) was activated by to-be-ignored, but attention-catching salient changes in auditory input streams. VMPFC may be involved in the evaluation of environmental events causing the bottom-up triggered engagement of attention. Auditory working memory activated a brain network that largely overlapped with the one activated by top-down controlled attention. The present results also provide further evidence of the role of the cerebellum in cognitive processing: During auditory working memory tasks, both activity in the posterior cerebellum (the crus I/II) and reaction speed increased when the cognitive load increased. Based on the present results and earlier theories on the role of the cerebellum in cognitive processing, the function of the posterior cerebellum in cognitive tasks may be related to the optimization of response speed.

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This study examined year seven students´ proactive coping, self-efficacy and social support seeking. Proactive coping was defined as a behaviour where obstacles are seen as a challenge. In proactive coping, individuals set goals, build up resources and regulate their behaviour to achieve the goals. Self-efficacy can be seen as people’s beliefs about their capabilities. Social support seeking was divided into instrumental support seeking and emotional support seeking. According to the theoretical frame of this study self-efficacy and social support seeking were seen as resources to proactive coping (Greenglass 2002). The participants were 445 year seven students (Mo= 13 years) from seven secondary schools. The data was collected in March-May 2008. The survey consisted 37 Likert-scaled items from the Proactive Coping Inventory and from the General Self-Efficacy Scale. The survey consisted of four scales: Proactive Coping, Instrumental Support Seeking, Emotional Support Seeking and General Self-Efficacy. The participants' age, gender and studying in specialist streams were asked as background information. As a result, most of the participants (62 % girls, 38 % boys) reported fairly strong proactive coping: they can see obstacles as a challenge and they set goals and regulate their behaviour to achieve the goals. Most of the participants reported that they seek instrumental and emotional support when having troubles. Girls reported more social support seeking than did boys and the mean difference was statistically significant. Most of the participants had fairly high sense of self-efficacy. However, 4 % of the participants reported that they don’t believe in their capabilities. Some of these participants reported that they neither use proactive coping nor seek informational or emotional support when having troubles. Proactive coping correlated positively with self-efficacy and with social support seeking. In this study self-efficacy and social support seeking explained 47 % of proactive coping. It was discussed that children’s high sense of self-efficacy and social relationships can act as protective factors in transition to secondary school. When supporting children’s self-efficacy and social relationships one also assists children’s proactive coping. Proactive coping can be seen to support children’s personal growth.

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Contamination of urban streams is a rising topic worldwide, but the assessment and investigation of stormwater induced contamination is limited by the high amount of water quality data needed to obtain reliable results. In this study, stream bed sediments were studied to determine their contamination degree and their applicability in monitoring aquatic metal contamination in urban areas. The interpretation of sedimentary metal concentrations is, however, not straightforward, since the concentrations commonly show spatial and temporal variations as a response to natural processes. The variations of and controls on metal concentrations were examined at different scales to increase the understanding of the usefulness of sediment metal concentrations in detecting anthropogenic metal contamination patterns. The acid extractable concentrations of Zn, Cu, Pb and Cd were determined from the surface sediments and water of small streams in the Helsinki Metropolitan region, southern Finland. The data consists of two datasets: sediment samples from 53 sites located in the catchment of the Stream Gräsanoja and sediment and water samples from 67 independent catchments scattered around the metropolitan region. Moreover, the sediment samples were analyzed for their physical and chemical composition (e.g. total organic carbon, clay-%, Al, Li, Fe, Mn) and the speciation of metals (in the dataset of the Stream Gräsanoja). The metal concentrations revealed that the stream sediments were moderately contaminated and caused no immediate threat to the biota. However, at some sites the sediments appeared to be polluted with Cu or Zn. The metal concentrations increased with increasing intensity of urbanization, but site specific factors, such as point sources, were responsible for the occurrence of the highest metal concentrations. The sediment analyses revealed, thus a need for more detailed studies on the processes and factors that cause the hot spot metal concentrations. The sediment composition and metal speciation analyses indicated that organic matter is a very strong indirect control on metal concentrations, and it should be accounted for when studying anthropogenic metal contamination patterns. The fine-scale spatial and temporal variations of metal concentrations were low enough to allow meaningful interpretation of substantial metal concentration differences between sites. Furthermore, the metal concentrations in the stream bed sediments were correlated with the urbanization of the catchment better than the total metal concentrations in the water phase. These results suggest that stream sediments show true potential for wider use in detecting the spatial differences in metal contamination of urban streams. Consequently, using the sediment approach regional estimates of the stormwater related metal contamination could be obtained fairly cost-effectively, and the stability and reliability of results would be higher compared to analyses of single water samples. Nevertheless, water samples are essential in analysing the dissolved concentrations of metals, momentary discharges from point sources in particular.

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The terrestrial export of dissolved organic matter (DOM) is associated with climate, vegetation and land use, and thus is under the influence of climatic variability and human interference with terrestrial ecosystems, their soils and hydrological cycles. The present study provides an assessment of spatial variation of DOM concentrations and export, and interactions between DOM, catchment characteristics, land use and climatic factors in boreal catchments. The influence of catchment characteristics, land use and climatic drivers on the concentrations and export of total organic carbon (TOC), total organic nitrogen (TON) and dissolved organic phosphorus (DOP) was estimated using stream water quality, forest inventory and climatic data from 42 Finnish pristine forested headwater catchments, and water quality monitoring, GIS land use, forest inventory and climatic data from the 36 main Finnish rivers (and their sub-catchments) flowing to the Baltic Sea. Moreover, the export of DOM in relation to land use along a European climatic gradient was studied using river water quality and land use data from four European areas. Additionally, the role of organic and minerogenic acidity in controlling pH levels in Finnish rivers and pristine streams was studied by measuring organic anion, sulphate (SO4) and base cation (Ca, Mg, K and Na) concentrations. In all study catchments, TOC was a major fraction of DOM, with much lower proportions of TON and DOP. Moreover, most of TOC and TON was in a dissolved form. The correlation between TOC and TON concentrations was strong and TOC concentrations explained 78% of the variation in TON concentrations in pristine headwater streams. In a subgroup of 20 headwater catchments with similar climatic conditions and low N deposition in eastern Finland, the proportion of peatlands in the catchment and the proportion of Norway spruce (Picea abies Karsten) of the tree stand had the strongest correlation with the TOC and TON concentrations and export. In Finnish river basins, TOC export increased with the increasing proportion of peatland in the catchment, whereas TON export increased with increasing extent of agricultural land. The highest DOP concentrations and export were recorded in river basins with a high extent of agricultural land and urban areas, reflecting the influence of human impact on DOP loads. However, the most important predictor for TOC, TON and DOP export in Finnish rivers was the proportion of upstream lakes in the catchment. The higher the upstream lake percentage, the lower the export indicating organic matter retention in lakes. Molar TOC:TON ratio decreased from headwater catchments covered by forests and peatlands to the large river basins with mixed land use, emphasising the effect of the land use gradient on the stoichiometry of rivers. This study also demonstrated that the land use of the catchments is related to both organic and minerogenic acidity in rivers and pristine headwater streams. Organic anion dominated in rivers and streams situated in northern Finland, reflecting the higher extent of peatlands in these areas, whereas SO4 dominated in southern Finland and on western coastal areas, where the extent of fertile areas, agricultural land, urban areas, acid sulphate soils, and sulphate deposition is highest. High TOC concentrations decreased pH values in the stream and river water, whereas no correlation between SO4 concentrations and pH was observed. This underlines the importance of organic acids in controlling pH levels in Finnish pristine headwater streams and main rivers. High SO4 concentrations were associated with high base cation concentrations and fertile areas, which buffered the effects of SO4 on pH.

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This thesis explores migration and the attractiveness of urban living in the Greater Helsinki region. The aim of the thesis is to explore the attractiveness of the city of Helsinki in terms of regional migration and to identify what characterizes migration to Helsinki. The study focuses in particular on housing, which is a key factor influencing migration decisions in the region. Other central themes in the study are housing policy and regional competition among municipalities. This study focuses solely on households moving within Finnish borders excluding international migration. Migration is examined by comparing in- and out-migration in Helsinki, as well as studying migration to the city s inner and outer areas. The primary research material in the study is a questionnaire data collected by the National Consumer Research Centre. In this thesis the data is used for studying migrants aged 25 45. The main research method is analyzing the data statistically using the SPSS software. Methods include frequency analysis, cross tabulation, factor analysis and descriptive analysis. Additionally, statistical data is used to complement the questionnaire data. The research results indicate that Helsinki s in- and out-migration differs both in terms of the type of households that migrate as well as in the reasons why they migrate. Furthermore, differences can also be detected between migration to the inner and outer parts of Helsinki. According to the research results, a household s current phase of life is crucial in determining where and why they move within the Greater Helsinki region. A household s set of values on the other hand, seems to have a lesser impact on migration within the region, even though households moving to Helsinki seem to value a somewhat more urban lifestyle than the ones moving out of the city. The research also shows a direct correlation between the values of migrants and their current phase of life. Decisions of migrating are heavily influenced by wider societal issues. In the Greater Helsinki region the labor and housing market appear to have a great influence on the direction of migration streams. According to the results, households move to and from Helsinki for different reasons. The primary reasons for moving to Helsinki are related to the city s diverse labor market and to the working careers of households. Issues related to urban living and an urban lifestyle seem to be relevant although not the main reason why people move to Helsinki. The research material indicates that Helsinki s urban environment is both a pull and a push factor affecting the decisions of migrants. The city attracts those seeking urban living, but on the contrary does not appeal to households seeking more space and wishing to live closer to nature. According to the research, Helsinki with its densely built urban environment mainly attracts singles and childless couples, whereas the city region s other municipalities are more attractive for families with children. Housing policy is one of the main reasons determining where people move within the Helsinki region. As for the city of Helsinki, improving the city s attractiveness seems to be closely linked to how well the city manages to execute its future housing policies and how well alternative living preferences can be taken into account in planning.

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"The functional organization of auditory cortex (AC) is still poorly understood. Previous studies suggest segregation of auditory processing streams for spatial and nonspatial information located in the posterior and anterior AC, respectively (Rauschecker and Tian, 2000; Arnott et al., 2004; Lomber and Malhotra, 2008). Furthermore, previous studies have shown that active listening tasks strongly modulate AC activations (Petkov et al., 2004; Fritz et al., 2005; Polley et al., 2006). However, the task dependence of AC activations has not been systematically investigated. In the present study, we applied high-resolution functional magnetic resonance imaging of the AC and adjacent areas to compare activations during pitch discrimination and n-back pitch memory tasks that were varied parametrically in difficulty. We found that anterior AC activations were increased during discrimination but not during memory tasks, while activations in the inferior parietal lobule posterior to the AC were enhanced during memory tasks but not during discrimination. We also found that wide areas of the anterior AC and anterior insula were strongly deactivated during the pitch memory tasks. While these results are consistent with the proposition that the anterior and posterior AC belong to functionally separate auditory processing streams, our results show that this division is present also between tasks using spatially invariant sounds. Together, our results indicate that activations of human AC are strongly dependent on the characteristics of the behavioral task."

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Purpose This paper takes a customer view on corporate image and value, and discusses the value of image in service. We propose a model depicting how the customer’s corporate brand image affects the customer’s value-in-use. Methodology/approach The paper represents conceptual development on customers’ value and image construction processes. By integrating ideas and elements from the current service and branding literature a model is proposed that extends current views on how value-in-use emerges. Findings From a current service perspective it is the customer who makes value assessments when experiencing service. Similarly, if branding is a concept used to denote the service provider’s intentions and attempts to create a corporate brand, image construction is the corresponding process where the customer constructs the corporate image. This image construction process is always present both in service interactions and in communication and has an effect on the customer’s value-in-use. We argue that two interrelated concepts are needed to capture corporate image construction and dynamics and value-in-use – the image-in-use and image heritage. Research implications The model integrates two different streams of research pointing to the need to consider traditional marketing communication and service interactions as inherently related to each other from the customer’s point of view. Additionally the model gives a platform for understanding how value-in-use emerges over time. New methodological approaches and techniques to capture image-in-use and image heritage and their interplay with value-in-use are needed. Practical implications The company may not be able to control the emergence of value-in-use but may influence it, not only in interactions with the customer but also with pure communication. Branding activities should therefore be considered related to service operations and service development. Additionally, practitioners would need to apply qualitative methods to understand the customer’s view on image and value-in-use. Originality/value The paper presents a novel approach for understanding and studying that the customer’s image of a company influences emergence of value-in-use. The model implies that the customer’s corporate image has a crucial role for experienced value-in-use.

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A short article summarizing the most visible streams of Mexican music along the last century. Special attention is paid to the intellectual and idiosyncratic components which are considered as elements of authenticity in Mexican culture.

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The area of Östersundom (29,1 square kilometers) was attached to Helsinki in the beginning of the year 2009. Östersundom is formed mostly from the municipality of Sipoo, and partly from the city of Vantaa. Nowadays Östersundom is still quite rural, but city planning has already started, and there are plans to develop Östersundom into a district with 45 000 inhabitants. In this study, the headwaters, streams and small lakes of Östersundom were studied to produce information as a basis for city planning. There are six main streams and five small lakes in Östersundom. The main methodology used in this study was the examination of the physical and the chemical quality of the water. The hygienic quality of the water was also studied. It was also examined whether the waters are in their natural state, or have they been treated and transformed by man. In addition, other factors affecting the waters were examined. Geographical information data was produced as a result of this work. Östersundom is the main area looked at in this study, some factors are examined in the scope of the catchment areas. Water samples were collected in three sampling periods: 31.8 4.9.2009, 3. 4.2.2010, and 10. 14.4.2010. There were 20 sampling points in Östersundom (5 in small lakes, 15 in streams). In the winter sampling period, only six samples were collected, from which one was taken from a small lake. Field measurements associated with water sampling included water temperature, oxygen concentration, pH and electoral conductivity. Water samples were analyzed in the Laboratories of Physical Geography in the University of Helsinki for the following properties: total suspended solids (TSS), total dissolved substances (TDS), organic matter, alkalinity, colour, principal anions and cations and trace elements. Metropolilab analyzed the amount of faecal coliform bacteria in the samples. The waters in Östersundom can be divided to three classes according to water quality and other characteristics: the upper course of the streams, the lower course of the streams and the small lakes. The streams in their upper course are in general acidic, and their acid neutralization capacity is low. The proportion of the organic matter is high. Also the concentrations of aluminium and iron tend to be high. The streams in the lower course have acidity closer to neutral, and the buffering capacity is good. The amounts of TSS and TDS are high, and as a result, the concentrations of many ions and trace elements are high as well. Bacteria were detected at times in the streams of the lower course. Four of the five small lakes in Östersundom are humic and acidic. TSS and TDS concentrations tend to be low, but the proportion of organic matter is often high. There were no bacteria in the small lakes. The fifth small lake (Landbonlampi) differs from the others by its water colour, which is very clear. This lake is very acidic, and its buffering capacity is extremely low. Compared to the headwaters in Finland in general, the concentrations of many ions and trace elements are higher in Östersundom. On the other hand, the characteristics of water were different according to the classification upper course streams, lower course streams, and small lakes. Generally, the best water quality was observed in the stream of Gumbölenpuro and in the lakes Storträsk, Genaträsk, Hältingträsk and Landbonlampi. Several valuable waters in their natural state were discovered from the area. The most representative example is the stream of Östersundominpuro in its lower course, where the stream flows through a broad-leaf forest area. The small lakes of Östersundom, and the biggest stream Krapuoja, with its meandering channel, are also valuable in their natural state.

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Calendula officinalis is grown widely as an ornamental plant across Europe. It belongs to the large. Asteraceae family. In this study, the aim was to explore the possibilities to use Calendula officinalis as a new model organism for flower development and secondary mechanism studies in Asteraceae. Tissue culture of Calendula officinalis was established using nine different cultivars. Murashige & Skoog (MS) medium with four different combinations of plant growth regulators were tested. Of all these combinations, the medium containing 1mg/l BAP, 0.1 mg/l IAA, and 1mg/l Zeatin achieved highest frequency of adventitious shoot regeneration from hypocotyl and cotyledon explants. Virus-induced gene silencing is a recent developed genetic tool for charactering the gene functions in plants, and extends the range of host plants that are not accessible for Agrobacterium transformation. Here, tobacco rattle virus (TRV)-based VIGS technique was tested in calendula (cv. Single Orange). We used TRV carrying Gerbera hybrid phytoene desaturase (PDS) gene fragment to induce PDS silencing in calendula. Vacuum infiltration and syringe infiltration methods both resulted in photo-bleaching phenotypes in leaves, bracts and petals. Loss-of-function phenotypes occurred on calendula 13 days post-infiltration. In conclusion, the data indicates that calendula explants can be regenerated through tissue culture which is a prerequisite for development of stable transformation methods. However, further optimization is still needed to improve the frequency. In addition, VIGS was applied to silence PDS marker gene expression indicating that this method has potential for gene functional studies in future.

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In recent years urban hydrology and individual urban streams have been in focus and subjects to research also in Helsinki. However, until now there has been lack of research covering simultaneously the whole area of the city of Helsinki. The aim of this study was to find out the general state of water quality in small urban streams in the city of Helsinki. 21 streams were studied: Mätäjoki, Korppaanoja, Mätäpuro, Näsinoja-Tuomarinkylänoja, Tuomarinkartanonpuro, Kumpulanpuro, Tapaninkylänpuro, Tapaninvainionpuro, Puistolanpuro, Longinoja, Säynäslahdenpuro, Viikinoja, Porolahdenpuro, Mustapuro, Marjaniemenpuro, Mellunkylänpuro, Vuosaarenpuro, Rastilanpuro, Ramsinkannaksenpuro, Skatanpuro and Yliskylänpuro. Water samples were collected from 48 sampling points, each stream having at least one point. Four water samples were collected from each point, sampling periods being 9.-11.2., 26.-28.4., 29.6.-1.7. and 25.-27.10.2004. Field measurements associated with water sampling included water temperature, oxygen concentration, pH and electrical conductivity. Water samples were analysed in the Laboratory of Physical Geography in the University of Helsinki and in the Environmental Laboratory of the City of Helsinki Environment Centre for following properties: suspended solids, dissolved substances, alkalinity, principal anions and cations (Na+, K+, Mg2+, Ca2+, F-, Cl-, NO3-, PO43- and SO42-), colour, turbidity, biological and chemical oxygen demand (BOD7 and CODMn-values), nutrient concentrations and bacterial indicators of hygienic quality. The main water quality issues found in this study were low oxygen levels in many streams and poor hygienic quality at least occasionally. E.g. in summer oxygen levels were under 60 % in every stream. Amount of total dissolved substances and nutrients were high in some of the streams studied. Compared to other Finnish streams the values of alkalinity and pH were higher. Although these problems were common, the variation between different streams and sampling points was significant. This was probably due to local conditions. Best overall water quality was found in Mätäpuro and Tuomarinkartanonpuro streams. Seasonal variation was evident in almost all water quality properties. For example the total amount of dissolved substances was largest in winter and decreased during the year. Colour and turbidity were smallest in winter and increased towards the end of the year. The same was true for suspended solids, which had smallest concentration in winter and greatest in autumn. It must be kept in mind that the spring samples were collected after the spring flood otherwise the largest suspended solid concentrations would have been expected in spring. Finnish general water quality classification was used to assess the quality of urban stream waters. Its suitability for small urban streams is not, however, completely trouble-free. This classification does not take into account the quick changes in such small streams but evaluates only the yearly mean values. This can oversimplify the picture of the water quality situation in the streams. Also in order to better reflect the urban environment the analysed water quality properties should also include total dissolved substances and e.g. concentrations of chloride and sodium.