992 resultados para Area de Conservación Osa


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Nurmiheinien merkitys maailmanlaajuisesti on merkittävä, sillä noin 69 % maapallon peltopinta-alasta on pysyvää laidunmaata tai niittyä. Suomessa nurmien osuus on noin 29 %, ja tuotanto perustuu pääosin intensiiviseen säilörehuntuotantoon. Yleisin nurmiheinälaji Suomessa on timotei (Phleum pratense ssp. pratense L.). Timotei on talvenkestävä ja soveltuu siksi pohjoisiin kasvuoloihin. Timoteilajikkeita jalostettaessa pohjoista alkuperää olevia vanhempaislinjoja käytetään hyvän talvenkestävyyden varmistamiseksi, eteläisiä tavoiteltaessa nopeaa kasvurytmiä. Ilmaston muutoksen ennustetaan lisäävän erilaisia äärioloja kuten myrskyjä ja sateita. Vuorokauden keskilämpötila nousee ja kasvukausi pidentyy. Lisäksi talvet muuttuvat sateisemmiksi. Muutokset näkyvät erityisesti pohjoisissa kasvuympäristöissä. Tutkimuksessa haluttiinkin selvittää eri alkuperää edustavien timoteilajikkeiden ja linjojen kylmänkestävyyttä, kasvu-, ja kehitysnopeutta sekä vernalisaation vaikutusta. Lisäksi tutkittiin syysviljojen vernalisaatiovasteen mittaamiseen käytettyjen menetelmien soveltuvuutta nurmille. Tutkimukseen kuului kaksivuotinen peltokoe sekä kasvatuskaappikoe. Vernalisaatio nopeutti timotein kasvua ja kehitystä. Tutkimuksen perusteella eteläistä alkuperää olevilla lajikkeilla kasvu- ja kukintavalmius oli olemassa ilman vernalisaatiota. Pohjoisilla lajikkeilla oli suurempi vernalisaatiovaste ja niiden kukkiminen ja kasvu nopeutui vernalisaation myötä. Vernalisaatiolla oli vaikutusta myös kasvuston rakenteeseen. Generatiivisten versojen määrä lisääntyi vernalisaation myötä, kun taas vegetatiivisten versojen määrä väheni. Kylmänkestävyys oli tutkimuksen perusteella riippuvainen syksyn karaistumisjakson pituudesta sekä jakson lämpösummasta (FH-COLD). Korkea keskilämpötila ja lyhyt karaistumisjakso heikensivät kylmänkestävyyttä. Vastaavasti karaistumiskauden lämpötilan ollessa välillä 0 °C:ta ja + 5 °C:ta ja jakson pituuden kasvaessa kylmänkestävyys lisääntyi. Tutkimuksen perusteella vernalisaatiolla oli selvä vaikutus timotein kasvuun ja kehitykseen. Pohjoista alkuperää olevat timoteit reagoivat vernalisaatioon eteläisiä enemmän. Osa pohjoisista linjoista vaati vernalisaation generatiivisten versojen muodostumiseen. Syysviljojen vernalisaatiovasteen mittausmenetelmät soveltuvat osin myös puhtaiden timoteilajikkeiden vernalisaation seurantaan.

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The loss and degradation of forest cover is currently a globally recognised problem. The fragmentation of forests is further affecting the biodiversity and well-being of the ecosystems also in Kenya. This study focuses on two indigenous tropical montane forests in the Taita Hills in southeastern Kenya. The study is a part of the TAITA-project within the Department of Geography in the University of Helsinki. The study forests, Ngangao and Chawia, are studied by remote sensing and GIS methods. The main data includes black and white aerial photography from 1955 and true colour digital camera data from 2004. This data is used to produce aerial mosaics from the study areas. The land cover of these study areas is studied by visual interpretation, pixel-based supervised classification and object-oriented supervised classification. The change of the forest cover is studied with GIS methods using the visual interpretations from 1955 and 2004. Furthermore, the present state of the study forests is assessed with leaf area index and canopy closure parameters retrieved from hemispherical photographs as well as with additional, previously collected forest health monitoring data. The canopy parameters are also compared with textural parameters from digital aerial mosaics. This study concludes that the classification of forest areas by using true colour data is not an easy task although the digital aerial mosaics are proved to be very accurate. The best classifications are still achieved with visual interpretation methods as the accuracies of the pixel-based and object-oriented supervised classification methods are not satisfying. According to the change detection of the land cover in the study areas, the area of indigenous woodland in both forests has decreased in 1955 2004. However in Ngangao, the overall woodland area has grown mainly because of plantations of exotic species. In general, the land cover of both study areas is more fragmented in 2004 than in 1955. Although the forest area has decreased, forests seem to have a more optimistic future than before. This is due to the increasing appreciation of the forest areas.

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In Helsinki's evangelical lutheran congregations, the share of the people being members of that church compared with all the people living in their specific geographical areas varies from 62,4 per cent in Paavali to 80,7 per cent in Munkkiniemi. The boundaries of the congregations are about to be redrawn to level the differences in the congregations. In this thesis, the reasons of the differences in Helsinki s districts were studied closer. The data consisted of statistical information gathered from the Population Information System of Finland. It included information by age groups about the population register keeper, marital status, native tongue, level of education and gender in the end of 2005. Additional data was gathered from Helsinki Region Statistics web service. It included information about the dwelling, level of income and main activities of the inhabitants in the districts. The main method was stepwise linear regression. Minor methods were crosstabulation and correlation matrixes. The result of the study was a statistical model that explains 72,2 per cent of the variation of the shares in the congregations. The dependent variable was the share of the people being members of evangelical lutheran church in the dirstricts. The independent variables were the share of the people having other than Finnish or Swedish as their native tongue, the share of rented apartments, the shares of apartments including four rooms and a kitchen, the share of detached houses in the districts and the shares of women and people with no income in the districts. The independent variables present in the model depict the amount of foreigners, dwellings, gender and the level of income of the population. The high share of foreigners, people with no income and rented apartments explain the low share of the people being members of evangelical lutheran church. On the contrary, the high share of the people being members of evangelical lutheran church in the district is explained by the large apartments, detached houses and amount of women living there.

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Accessibility is a crucial factor for interaction between areas in economic, cultural, political and environmental terms. Therefore, information concerning accessibility is relevant for informed decision making, planning and research. The Loreto region in the Peruvian Amazonia provides an interesting scene for an accessibility study. Loreto is sparsely populated and because there are few roads in the region, in practice all movement and transportation happens along the river network. Due to the proximity of the Andes, river dynamics are strong and annual changes in water level combined with these dynamic processes constantly reshape accessibility patterns of the region. Selling non-timber forest products (NTFP) and agricultural products (AP) in regional centres is an important income source for local rain forest dwellers. Thus, accessibility to the centres is crucial for the livelihood of local population. -- In this thesis I studied how accessible the regional centre Iquitos is from other parts of Loreto. In addition, I studied the regional NTFP/AP trade patterns and compared them with patterns of accessibility. Based on GPS-measurements, using GIS, I created a time-distance surface covering Loreto. This surface describes the time-distance to Iquitos, along the river network. Based on interview material, I assessed annual changes to accessibility patterns in the region. The most common regional NTFP/AP were classified according to the amount of time they can be preserved, and based on the accessibility surface, I modelled a catchment area for each of these product classes. -- According to my results, navigation speeds vary considerably in different parts of the river network, depending on river types, vessels, flow direction and season. Navigating downstream is, generally, faster than upstream navigation. Thus, Iquitos is better accessible from areas situated south and south west of the city, like along the rivers Ucayali and Marañon. Differences in accessibility between different seasons are also substantial: during the dry season navigation is slower due to lower water levels and emerging sand bars. Regularly operating boats follow routes only along certain rivers and close to Iquitos transport facilities are more abundant than in more distant areas. Most of the products present in Iquitos market places are agricultural products, and the share of NTFP is significantly smaller. Most of the products were classified in product class 2, and the catchment area for these products is rather small. Many products also belonged to class 5, and the catchment area for these products reaches up to the edges of my study area, following the patterns of the river network. -- The accessibility model created in this study predicts travel times relatively well, although in some cases the modelled time-distances are substantially shorter than observed time-distances. This is partly caused by the fact that real-life navigation routes are more complicated than the modelled routes. Rain forest dwellers having easier access to Iquitos have more opportunities in terms of the products they decide to market. Thus, they can better take advantage of other factors affecting the market potential of different products. -- In all, understanding spatial variation in accessibility is important. In the Amazonian context it is difficult to combine the accessibility-related needs of the local dwellers with conservation purposes and the future challenge lies in finding solution that satisfy both of these needs.

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Road transport and infrastructure has a fundamental meaning for the developing world. Poor quality and inadequate coverage of roads, lack of maintenance operations and outdated road maps continue to hinder economic and social development in the developing countries. This thesis focuses on studying the present state of road infrastructure and its mapping in the Taita Hills, south-east Kenya. The study is included as a part of the TAITA-project by the Department of Geography, University of Helsinki. The road infrastructure of the study area is studied by remote sensing and GIS based methodology. As the principal dataset, true colour airborne digital camera data from 2004, was used to generate an aerial image mosaic of the study area. Auxiliary data includes SPOT satellite imagery from 2003, field spectrometry data of road surfaces and relevant literature. Road infrastructure characteristics are interpreted from three test sites using pixel-based supervised classification, object-oriented supervised classifications and visual interpretation. Road infrastructure of the test sites is interpreted visually from a SPOT image. Road centrelines are then extracted from the object-oriented classification results with an automatic vectorisation process. The road infrastructure of the entire image mosaic is mapped by applying the most appropriate assessed data and techniques. The spectral characteristics and reflectance of various road surfaces are considered with the acquired field spectra and relevant literature. The results are compared with the experimented road mapping methods. This study concludes that classification and extraction of roads remains a difficult task, and that the accuracy of the results is inadequate regardless of the high spatial resolution of the image mosaic used in this thesis. Visual interpretation, out of all the experimented methods in this thesis is the most straightforward, accurate and valid technique for road mapping. Certain road surfaces have similar spectral characteristics and reflectance values with other land cover and land use. This has a great influence for digital analysis techniques in particular. Road mapping is made even more complicated by rich vegetation and tree canopy, clouds, shadows, low contrast between roads and surroundings and the width of narrow roads in relation to the spatial resolution of the imagery used. The results of this thesis may be applied to road infrastructure mapping in developing countries on a more general context, although with certain limits. In particular, unclassified rural roads require updated road mapping schemas to intensify road transport possibilities and to assist in the development of the developing world.

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High performance video standards use prediction techniques to achieve high picture quality at low bit rates. The type of prediction decides the bit rates and the image quality. Intra Prediction achieves high video quality with significant reduction in bit rate. This paper present an area optimized architecture for Intra prediction, for H.264 decoding at HDTV resolution with a target of achieving 60 fps. The architecture was validated on Virtex-5 FPGA based platform. The architecture achieves a frame rate of 64 fps. The architecture is based on multi-level memory hierarchy to reduce latency and ensure optimum resources utilization. It removes redundancy by reusing same functional blocks across different modes. The proposed architecture uses only 13% of the total LUTs available on the Xilinx FPGA XC5VLX50T.

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Reaction between the various species in slag and metal phase is usually mass transfer controlled. There have been continuous efforts to increase the reaction efficiency in slag-metal system, especially during decarburization of steel to produce the ultra low carbon steel (ULCS) in secondary steelmaking. It has been found that the surface reaction is a dominant factor in the final stage of decarburization. In the initial stage, the inner site reaction is major factor in the refining process. The mixing of bath affects the later reaction. However, the former reaction (surface reaction) is affected by the plume size area at the top of the metal surface. Therefore, a computational study has been made to understand the fluid dynamics of a new secondary steelmaking process called Revolutionary Degasser Activator (REDA) to study the bath mixing and plume area. REDA process has been considered as it is claimed that this process can reduce the carbon content in steel below 10ppm in a less time than the other existing processes such as RH and Tank degasser. This study shows that both bath mixing and plume area are increased in REDA process facilitating it to give the desired carbon content in less time. Qualitative comments are made on slag-metal reaction system based on this finding.

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Studies have been carried out to recover copper from vanadiferrous magnetite ores by a novel reaction with lime in the presence of water vapour. The ore, mixed with different proportions of lime, has been roasted in the presence of steam. The roasted product is either directly leached with dilute mineral acids or subjected to magnetic separation and then leached. The effect of various parameters such as amount of lime added, temperature and duration of roasting and time of leaching on the recovery of copper has been investigated. The results indicate that over 90% copper could be recovered under optimum conditions of roasting and leaching.

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A series of novel, microporous polymer networks (MPNs) have been generated in a simple, acid catalysed Friedel-Crafts-type self-condensation of A(2)B(2)- and A(2)B(4)-type fluorenone monomers. Two A2B4-type monomers with 2,7-bis(N, N-diphenylamino) A or 2,7-bis [4-(N, N-diphenylamino) phenyl] D substitution of the fluorenone cores lead to MPNs with high S(BET) surface areas of up to 1400 m(2) g(-1). Two MPNs made of binary monomer mixtures showed the highest Brunauer-Emmett-Teller (BET) surface areas S(BET) of our series (SBET of up to 1800 m(2) g(-1)) after washing the powdery samples with supercritical carbon dioxide. Total pore volumes of up to 1.6 cm(3) g(-1) have been detected. It is observed that the substitution pattern of the monomers is strongly influencing the resulting physicochemical properties of the microporous polymer networks (MPNs).

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Prior work on modeling interconnects has focused on optimizing the wire and repeater design for trading off energy and delay, and is largely based on low level circuit parameters. Hence these models are hard to use directly to make high level microarchitectural trade-offs in the initial exploration phase of a design. In this paper, we propose INTACTE, a tool that can be used by architects toget reasonably accurate interconnect area, delay, and power estimates based on a few architecture level parameters for the interconnect such as length, width (in number of bits), frequency, and latency for a specified technology and voltage. The tool uses well known models of interconnect delay and energy taking into account the wire pitch, repeater size, and spacing for a range of voltages and technologies.It then solves an optimization problem of finding the lowest energy interconnect design in terms of the low level circuit parameters, which meets the architectural constraintsgiven as inputs. In addition, the tool also provides the area, energy, and delay for a range of supply voltages and degrees of pipelining, which can be used for micro-architectural exploration of a chip. The delay and energy models used by the tool have been validated against low level circuit simulations. We discuss several potential applications of the tool and present an example of optimizing interconnect design in the context of clustered VLIW architectures. Copyright 2007 ACM.

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H.264 is a video codec standard which delivers high resolution video even at low bit rates. To provide high throughput at low bit rates hardware implementations are essential. In this paper, we propose hardware implementations for speed and area optimized DCT and quantizer modules. To target above criteria we propose two architectures. First architecture is speed optimized which gives a high throughput and can meet requirements of 4096x2304 frame at 30 frames/sec. Second architecture is area optimized and occupies 2009 LUTs in Altera’s stratix-II and can meet the requirements of 1080HD at 30 frames/sec.

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Chronic recording of neural signals is indispensable in designing efficient brain–machine interfaces and to elucidate human neurophysiology. The advent of multichannel micro-electrode arrays has driven the need for electronics to record neural signals from many neurons. The dynamic range of the system can vary over time due to change in electrode–neuron distance and background noise. We propose a neural amplifier in UMC 130 nm, 1P8M complementary metal–oxide–semiconductor (CMOS) technology. It can be biased adaptively from 200 nA to 2 $mu{rm A}$, modulating input referred noise from 9.92 $mu{rm V}$ to 3.9 $mu{rm V}$. We also describe a low noise design technique which minimizes the noise contribution of the load circuitry. Optimum sizing of the input transistors minimizes the accentuation of the input referred noise of the amplifier and obviates the need of large input capacitance. The amplifier achieves a noise efficiency factor of 2.58. The amplifier can pass signal from 5 Hz to 7 kHz and the bandwidth of the amplifier can be tuned for rejecting low field potentials (LFP) and power line interference. The amplifier achieves a mid-band voltage gain of 37 dB. In vitro experiments are performed to validate the applicability of the neural low noise amplifier in neural recording systems.