913 resultados para Nearest Neighbour


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The Ebro Delta holds a large seabird community, including a common tern (Sterna hirundo) local population of 3,085 pairs in 2000 which breeds scattered in several colonies. At El Canalot colony, 1,178 (1999) and 1,156 pairs (2000) of this species bred distributed in 32 and 38 sub-colonies respectively. These sub-colonies varied in size from 1 to 223 pairs and were placed near the main breeding colonies of yellow-legged gulls (Larus cachinnans) and Audouin´s gulls (L. audouinii), which are potential egg-predators of terns. We studied egg predation during 1999 (6 sub-colonies) and 2000 (27 sub-colonies). Overall, we found that 10.6% of the nests in 1999 and 16.7% in 2000 suffered partial or total egg predation, being total in 81.1% of the predatory events. Predation was significantly higher in small sub-colonies (< 11 pairs): 49.4% in 1999 and 75.5% in 2000. Only attacks from yellow-legged gulls were observed, and defence behaviour of terns was significantly more frequent against this gull species (40.5 hours of observation), suggesting that in most cases the egg predation recorded was due to this species. Probability of egg predation was significantly and negatively correlated with distance to the nearest yellow-legged gull sub-colony, although this relationship was no more significant after adjustment for sub-colony size. On the other hand, distance to the nearest Audouin´s gull sub-colony did not show any effect. Our results suggest that the impact of large gulls (at least yellow-legged gulls) upon smaller seabirds breeding in the area might be important, especially when they are breeding in small sub-colonies. Further studies are needed to analyse the general impact of large gulls upon the breeding populations of other colonial bird species in the area.

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We consider the problem of multiple correlated sparse signals reconstruction and propose a new implementation of structured sparsity through a reweighting scheme. We present a particular application for diffusion Magnetic Resonance Imaging data and show how this procedure can be used for fibre orientation reconstruction in the white matter of the brain. In that framework, our structured sparsity prior can be used to exploit the fundamental coherence between fibre directions in neighbour voxels. Our method approaches the ℓ0 minimisation through a reweighted ℓ1-minimisation scheme. The weights are here defined in such a way to promote correlated sparsity between neighbour signals.

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Miller and Gerlai proposed two methods for determining shoal membership in Danio rerio, one based on momentary mean inter-individual distances and the other on post hoc analysis of the trajectories of nearest-neighbor distances. We propose a method based on momentary nearest-neighbor distances and compare the three methods using simulation. In general, our method yielded results that were more similar to their second method than their first one, and is computationally simpler.

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[cat] Presentem un model estadístic de l’especialització vitícola a la província de Barcelona cap el 1860 que combina la pressió boserupiana de l’augment de població, l’atracció de la demanda induïda per un creixement de tipus smithià (mesurada per les distancies horàries al port més proper), i l’adequació dels sòls disponibles per sembrar gra o plantar ceps (mesurada per l’estès hídric, el pendent i el risc de glaçades). L’assoliment global d’uns nivells de R2 ajustats que oscil·len entre 0,608 i 0,826 poden considerar-se força bons. Creiem que la desigualtat en la propietat de la terra també va jugar un paper molt important, però l’hem hagut d’ometre de moment per manca de dades estadístiques. També cal aprofundir en el tractament del problema de possible endogeneïtat derivat de l’ús de variables socio-demogràfiques.

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[cat] Presentem un model estadístic de l’especialització vitícola a la província de Barcelona cap el 1860 que combina la pressió boserupiana de l’augment de població, l’atracció de la demanda induïda per un creixement de tipus smithià (mesurada per les distancies horàries al port més proper), i l’adequació dels sòls disponibles per sembrar gra o plantar ceps (mesurada per l’estès hídric, el pendent i el risc de glaçades). L’assoliment global d’uns nivells de R2 ajustats que oscil·len entre 0,608 i 0,826 poden considerar-se força bons. Creiem que la desigualtat en la propietat de la terra també va jugar un paper molt important, però l’hem hagut d’ometre de moment per manca de dades estadístiques. També cal aprofundir en el tractament del problema de possible endogeneïtat derivat de l’ús de variables socio-demogràfiques.

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The paper is focused on feasibility study and market review of small scale bioenergy heating plants in the Russian North-West region. The main focus is effective and competitive usage of low-grade wood for heating purposes in the region. As example of economical feasibility estimation it was chosen the project of reconstruction of small scale boiler plant in Leningrad region that Brofta Oy is planning to implement the nearest time. It includes calculation the payback time with and without interest, the estimation of probable investments, the evaluation of possible risks and research on the potential of small scale heating plants projects. Calculations show that the profitability of this kind of projects is high, but payback time is not very short, because of high level of initial investments. Though, the development of small scale bioenergy heating plants in the region is considered to be the best way to solve the problems of heat supply in small settlements using own biomass resources.

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This thesis represents an overview of biomass gasification technology together with some practical aspects of this technology application for transport in Finland. The main aim of this work is an assessment whether this technology is perspective in the nearest future for the wide use on transport or not. The first part of the thesis is a kind of survey of the previous works and materials con-cerning the usage of biomass gasification for transport. The second part concentrates more on the practical moments of its use for mobile applications in Finland (taxation, emissions, etc.).

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Background: Epidemiological evidence of the effects of long-term exposure to air pollu tion on the chronic processes of athero genesis is limited. Objective: We investigated the association of long-term exposure to traffic-related air pollu tion with subclinical atherosclerosis, measured by carotid intima media thickness (IMT) and ankle–brachial index (ABI). Methods: We performed a cross-sectional analysis using data collected during the reexamination (2007–2010) of 2,780 participants in the REGICOR (Registre Gironí del Cor: the Gerona Heart Register) study, a population-based prospective cohort in Girona, Spain. Long-term exposure across residences was calculated as the last 10 years’ time-weighted average of residential nitrogen dioxide (NO2) estimates (based on a local-scale land-use regression model), traffic intensity in the nearest street, and traffic intensity in a 100 m buffer. Associations with IMT and ABI were estimated using linear regression and multinomial logistic regression, respectively, controlling for sex, age, smoking status, education, marital status, and several other potential confounders or intermediates. Results: Exposure contrasts between the 5th and 95th percentiles for NO2 (25 μg/m), traffic intensity in the nearest street (15,000 vehicles/day), and traffic load within 100 m (7,200,000 vehicle-m/day) were associated with differences of 0.56% (95% CI: –1.5, 2.6%), 2.32% (95% CI: 0.48, 4.17%), and 1.91% (95% CI: –0.24, 4.06) percent difference in IMT, respectively. Exposures were positively associated with an ABI of > 1.3, but not an ABI of < 0.9. Stronger associations were observed among those with a high level of education and in men ≥ 60 years of age. Conclusions: Long-term traffic-related exposures were associated with subclinical markers of atherosclerosis. Prospective studies are needed to confirm associations and further examine differences among population subgroups.key words: ankle–brachial index, average daily traffic, cardiovascular disease, exposure assessment, exposure to tailpipe emissions, intima media thickness, land use regression model, Mediterranean diet, nitrogen dioxide

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This thesis is devoted to investigations of three typical representatives of the II-V diluted magnetic semiconductors, Zn1-xMnxAs2, (Zn1-xMnx)3As2 and p-CdSb:Ni. When this work started the family of the II-V semiconductors was presented by only the compounds belonging to the subgroup II3-V2, as (Zn1-xMnx)3As2, whereas the rest of the materials mentioned above were not investigated at all. Pronounced low-field magnetic irreversibility, accompanied with a ferromagnetic transition, are observed in Zn1-xMnxAs2 and (Zn1-xMnx)3As2 near 300 K. These features give evidence for presence of MnAs nanosize magnetic clusters, responsible for frustrated ground magnetic state. In addition, (Zn1-xMnx)3As2 demonstrates large paramagnetic response due to considerable amount of single Mn ions and small antiferromagnetic clusters. Similar paramagnetic system existing in Zn1-xMnxAs2 is much weaker. Distinct low-field magnetic irreversibility, accompanied with a rapid saturation of the magnetization with increasing magnetic field, is observed near the room temperature in p- CdSb:Ni, as well. Such behavior is connected to the frustrated magnetic state, determined by Ni-rich magnetic Ni1-xSbx nanoclusters. Their large non-sphericity and preferable orientations are responsible for strong anisotropy of the coercivity and saturation magnetization of p- CdSb:Ni. Parameters of the Ni1-xSbx nanoclusters are estimated. Low-temperature resistivity of p-CdSb:Ni is governed by a hopping mechanism of charge transfer. The variable-range hopping conductivity, observed in zero magnetic field, demonstrates a tendency of transformation into the nearest-neighbor hopping conductivity in non-zero magnetic filed. The Hall effect in p-CdSb:Ni exhibits presence of a positive normal and a negative anomalous contributions to the Hall resistivity. The normal Hall coefficient is governed mainly by holes activated into the valence band, whereas the anomalous Hall effect, attributable to the Ni1-xSbx nanoclusters with ferromagnetically ordered internal spins, exhibits a low-temperature power-law resistivity scaling.

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Aerosol size distributions from 6 to 700 nm were measured simultaneously at an urban background site and a roadside station in Oporto. The particle number concentration was higher at the traffic exposed site, where up to 90% of the size spectrum was dominated by the nucleation mode. Larger aerosol mode diameters were observed in the urban background site possibly due to the coagulation processes or uptake of gases during transport. Factor analysis has shown that road traffic and the neighbour stationary sources localised upwind affect the urban area thought intra-regional pollutant transport.

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Density Functional Theory (DFT) calculations on the interactions of small atoms (H, C, O, and S) on first-row transition metal clusters were performed. The results show that the adsorption site may vary between the metal surface and the edge of the cluster. The adsorption energies, adatom-nearest neighbor and adatom-metal plane distances were also determined. Finally, the authors present a discussion about the performance of these metals as anodes on solid oxide fuel cells. The results obtained agree with empirical data, indicating that the theoretical model used is adequate

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Raman imaging spectroscopy is a highly useful analytical tool that provides spatial and spectral information on a sample. However, CCD detectors used in dispersive instruments present the drawback of being sensitive to cosmic rays, giving rise to spikes in Raman spectra. Spikes influence variance structures and must be removed prior to the use of multivariate techniques. A new algorithm for correction of spikes in Raman imaging was developed using an approach based on comparison of nearest neighbor pixels. The algorithm showed characteristics including simplicity, rapidity, selectivity and high quality in spike removal from hyperspectral images.

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In May 1950 a trip was undertaken by the ships "Baependi" and "Vega" to the Trindade Island - 20º30'S and 29º20'W - Approximately 1200 km off the coast of Espirito Santo State. This scientific expedition was realized by the iniciative of the Minister J. A. Lins de Barros. In this expedition the supervisor of the oceanographic works was Prof. W. Besnard, the director of the São Paulo Oceanographic Institute. He brougth home 42 samples of water for study, collected upon the insular terrace of the island, referring to the 15 established stations - see table I - with depths varying between 0 m and 115 m. The physical and chemical properties of them are to be seen on table II. The results obtained were compared with those of the German Expedition to the South Atlantic, 1925/27 ("Meteor"), observed at the stations 157-158-159-163 of profile VI and 168-169-170 of profile VII. The mean results obtaneid by the boats "Baependi" and "Vega" are represented on table IV. We constructed vertical sections - I to VI - of each group of Stations, showing the slope of the insular shelves and, in a general manner, the distribution of salinity. We made also longitudinal section - E, M, I - involving the island and corresponding, respectively, to the groups of stations, the farthest, nearest and intermediary ones. As the number of samples received is reduced and consequently the data obtained are few, no conclusions could be deduced. We made only a commentary supposing that the predominating waters surrounding the island are the same as those coming from the mentioned stations on Profile VI, marked by the "Meteor". No indication authorizes the supposition that waters of the Brazil Current or those of Profile VII of the "Meteor" reach the Trindade Island. On the contrary, its waters must be warm and salted to which Albert Defant (Die Troposphaere, Wiss. Erg. D. Atl. Exp. "Meteor" Band VI, 1 Tel Lief. 3, Berlin, 1936) has referred, as the island is located very near to the limits of the perspective diagram of warm water circulation pointed out. (Kieler Meeresforschungen, Inst. Meereskunde, Universit. Kiel, Band VII, Heft 1, S 24, 1950).

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Satelliittipaikannuksen hyödyntäminen eri sovellusaloilla ja siviilikäytössä on kasvanut merkittävästi 2000-luvulla Yhdysvaltojen puolustusministeriön lopetettua GPS-järjestelmän tarkoituksenmukaisen häirinnän. Langattomien datayhteyksien yleistyminen ja nopeuksien kasvaminen on avannut paikkatiedon käyttämiseksi ja hyödyntämiseksi reaaliaikaisesti uusia mahdollisuuksia. Kustannusten kasvaessa on tehokkaasta liikennöinnistä tullut tänä päivänä erittäin tärkeä osa yritysten päivittäisiä toimintoja. Ajoneuvojen hallinta on yksi tapa, jolla pyritään tehostamaan logistisia toimintoja ja vähentämään siitä aiheutuvia kustannuksia. Seuraamalla reaaliaikaisesti ajoneuvojen liikennöintiä voidaan pyrkiä saavuttamaan säästöjä optimoimalla aikatauluja ja reittejä sekä uudelleenohjaamalla ajoneuvoja sijaintien mukaan vähentäen näin kuljettua matkaa ja aikaa. Tässä diplomityössä tavoitteena on tutkia kuinka satelliittipaikannusta, paikkatietoa ja langattomia datayhteyksiä hyödyntämällä voidaan toteuttaa reaaliaikainen jäljitysohjelmisto. Työssä esitellään aluksi paikannustekniikat ja niiden toiminta. Lisäksi tutkitaan kuinka tiedonsiirto voidaan järjestelmässä toteuttaa sekä tarkastellaan järjestelmän kehityksessä huomioitavia tietoturvanäkökohtia. Tutkimuksen pohjalta suunniteltiin ja toteutettiin reaaliaikainen jäljitysohjelmisto kotipalveluyrityksen ajoneuvojen paikannustarpeisiin. Järjestelmän avulla voidaan valvoa ja jäljittää ajoneuvojen sijainteja kartalla reaaliaikaisesti sekä paikantaa tiettyä kohdetta lähimpänä olevat ajoneuvot. Tämä mahdollistaa hälytyksen sattuessa lähimpänä olevan työntekijän lähettämisen asiakaskohteeseen mahdollisimman nopeasti. Järjestelmän avulla käyttäjät voivat lisäksi seurata ajamiaan matkoja ja pitää automaattista ajopäiväkirjaa. Lopuksi työssä arvioidaan toteutetun järjestelmän toimintaa testauksessa saatujen mittaustulosten perusteella.

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Työn tavoitteena oli selvittää, miten asutuksen läheisyydessä sijaitsevasta kivilinjasta aiheutuvat merkittävät ympäristövaikutukset muuttuvat, kun kivilinja siirretään kallion sisältä maan pinnalle. Kivilinjan aiheuttamia merkittäviä ympäristövaikutuksia ovat erityisesti melu ja pöly. Lisäksi työssä tarkasteltiin toiminnan muutoksesta aiheutuvia vaikutuksia kasvillisuuteen ja eläimistöön, liikennevirtoihin sekä pinta- ja pohjavesiin. Työssä tarkasteltiin myös uuden kivilinjan vaikutuksia yrityksen sisäisiin ympäristönäkökohtiin, kuten työolosuhteiden hallintaan. Työssä laskettiin äänitaso lähimmässä häiriintyvässä kohteessa uuden kivilinjan rakentamisen jälkeen. Äänitaso ei todennäköisesti uuden kivilinjan käyttöönoton myötä tule ylittämään ympäristöluvassa asetettuja raja-arvoja. Kasvillisuuteen ja eläimistöön uudella kivilinjalla voi olla sekä positiivisia että negatiivisia vaikutuksia. Vesistövaikutukset eivät todennäköisesti tule olemaan merkittäviä. Alueen liikennevirtoihin tulee uuden kivilinjan käyttöönoton myötä muutoksia. Ajettavien kilometrien määrä vähenee noin 18 000 kilometriä. Erityisesti prosessin loppupään ajokilometrit vähenevät huomattavasti.