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Registros recuperados: 8
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Indices of movement behaviour: conceptual background, effects of scale and location errors Rev. Bras. Zool.
Almeida,Paulo J. A. L.; Vieira,Marcus V.; Kajin,Maja; Forero-Medina,German; Cerqueira,Rui.
A fundamental step in the emerging Movement Theory is the description of movement paths, and the identification of its proximate and ultimate drivers. The most common characteristic used to describe and analyze movement paths is its tortuosity, and a variety of tortuosity indices have been proposed in different theoretical or empirical contexts. Here we review conceptual differences between five movement indices and their bias due to locations errors, sample sizes and scale-dependency: Intensity of Habitat use (IU), Fractal D, MSD (Mean Squared Distance), Straightness (ST), and Sinuosity (SI). Intensity of Habitat use and ST are straightforward to compute, but ST is actually an unbiased estimator of oriented search and ballistic movements. Fractal D is...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Diffusion; Fractal dimension; Oriented search; Random walk; Search behaviour.
Ano: 2010 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702010000500002
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Dynamique des matières en suspension en mer cotière : caractérisation, quantification et interactions sédiments/matière organique ArchiMer
Chapalain, Marion.
The knowledge of suspended particulate matter (SPM) and turbidity dynamics in coastal waters is essential for studying marine ecosystems. Flocculation/deflocculation processes are crucial mechanisms controlling the dynamics of SPM physical characteristics and thus, the fate of these SPM in the environment. This PhD thesis focuses on the SPM characteristics and their dynamics in coastal waters, from tidal to annual scales, in response to hydrodynamic, hydrological and biological forcing that take place at the interface between estuaries and coastal seas. To this end, optical and acoustic sensors were deployed in situ through 6 field campaigns in 2016, in order to characterize and quantify SPM in the water column, near the mouth of the Seine estuary...
Tipo: Text Palavras-chave: Matière en suspension (MES); Floculation; Matière organique; Distribution en classe de taille; Dimension fractale; Capteurs optiques et acoustiques; Baie de Seine; Suspended particulate matter (SPM); Flocculation; Organic matter; Particle size distribution; Fractal dimension; Optical and acoustic sensors; Seine Bay.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00500/61155/64591.pdf
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Evidence of Fractality in a Pattern of Crystallization of Bovine Cervical Mucus Obtained at Oestrus International Journal of Morphology
Cortés,Manuel E; Hauyón,Roberto; González,Fernando; Vigil,Pilar.
Fractality has emerged as a feature of the organization of some complex natural systems. Several biological secretions show fractal-like patterns for their crystallization phenomena but their presence in crystallizations of bovine cervical mucus (BCM) is yet unknown. In order to assess the fractality of BCM crystallization, samples of this fluid were taken from heifers at oestrus, their crystalline patterns photographed and its morphology analyzed. Among the many images obtained for BCM crystallizations, one of them had a highly symmetrical geometric arrangement, possessing three zones characterized by pine-like, arboriform structures, evidencing a remarkable similarity between them. Moreover, fractal dimensions obtained for these zones were statistically...
Tipo: Journal article Palavras-chave: Bovine cervical mucus; Cervical mucus crystallization; Fractal dimension; Fractality; Oestrus.
Ano: 2012 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-95022012000400031
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Can the fractal dimension be applied for the early diagnosis of non-proliferative diabetic retinopathy? BJMBR
Kunicki,A.C.B.; Oliveira,A.J.; Mendonça,M.B.M.; Barbosa,C.T.F.; Nogueira,R.A..
The fractal dimension has been employed as a useful parameter in the diagnosis of retinal disease. Avakian et al. (Curr Eye Res 2002; 24: 274-280), comparing the vascular pattern of normal patients with mild to moderate non-proliferative diabetic retinopathy (NPDR), found a significant difference between them only in the macular region. This significant difference in the box-counting fractal dimension of the macular region between normal and mild NPDR patients has been proposed as a method of precocious diagnosis of NPDR. The aim of the present study was to determine if fractal dimensions can really be used as a parameter for the early diagnosis of NPDR. Box-counting and information fractal dimensions were used to parameterize the vascular pattern of the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Box-counting; Fractal dimension; Information fractal dimension; Retina; Vascularization; Non-proliferative diabetic retinopathy.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009001000009
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Multifractal analysis of soil penetration resistance under sugarcane cultivation AGRIAMBI
Leiva,Jairo O. R.; Silva,Raimunda A.; Buss,Ricardo N.; França,Victor L.; Souza,Anderson A.; Siqueira,Glécio M..
ABSTRACT Soil resistance to penetration (PR) is an indirect measure of the state of soil compaction. Thus, the objective of this study was to characterize PR in vertical profiles in an area cultivated with sugarcane using multifractal models for different relief units. The experiment was carried out in an Oxisol with a clay texture, with 6.85 ha in the municipality of Coelho Neto (Maranhão state, Brazil), where 60 sampling points were demarcated. The area was divided into four relief units (Type A > 74 m, Type B from 71 to 74 m, Type C from 68 to 71 m and Type D from 65 to 68 m). The PR was measured at the 60 sampling points using an impact penetrometer, and the PR determined in the 0-0.60 m depth layer every 0.01 m. The multifractal analysis was...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Fractal geometry; Fractal dimension; Singularity spectrum; Geostatistics; Soil management.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662019000700538
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Geometry, fractal dimension and settling velocity of flocs during flooding conditions in the Rhône ROFI ArchiMer
Many, G; Durrieu De Madron, Xavier; Verney, Romaric; Bourrin, F; Renosh, Pr; Jourdin, F; Gangloff, A.
Regions Of Freshwater Influence (ROFI) are of particular interest in a source-to-sink approach in terms of sediment advection, settling, and deposition in the coastal zone. An experiment was carried out in the ROFI of the Rhône River in February 2016 to describe the properties of suspended particulate matter (SPM) during a flood event. A digital holographic camera (LISST-HOLO, 20–2000 μm) was used to estimate the variability of fine sediment floc properties (size, nature and shape) formed in the Rhône mouth. An automatic image toolbox was developed to classify the different constituents of the SPM (as diatoms, bubbles and flocs) and to describe the diversity of floc shapes existing in the material in suspension. We estimated the fractal dimension (DF3D),...
Tipo: Text Palavras-chave: Flocculation; Fractal dimension; Settling velocity; ROFI; Rhone.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00478/58952/61540.pdf
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Examples of spatial and temporal variations of some fine-grained suspended particle characteristics in two Danish coastal water bodies ArchiMer
Mikkelsen, Oa.
In June and September of 1999, a LISST-100 in situ laser diffraction particle sizer was used to analyse the temporal and spatial variation of the beam attenuation coefficient, the in situ median particle (aggregate) diameter and the median volume concentration of suspended matter in two Danish coastal water bodies. One of the study sites was generally exposed to wind, while the other was quite sheltered. Measurements of the mass concentration of total suspended matter and chl a were made simultaneously. The in situ median effective density, settling velocity and vertical flux of the suspended matter are computed. Results demonstrate that in September, the in situ median aggregate diameter, settling velocity and vertical flux was smaller (by a factor of up...
Tipo: Text Palavras-chave: Agrégation; Diffraction laser; Spectre de taille des particules; Dimension fractale; Vitesse de sédimentation; Aggregation; Laser diffraction; Particle size spectra; Fractal dimension; Settling velocity.
Ano: 2002 URL: http://archimer.ifremer.fr/doc/00322/43328/42899.pdf
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Soil roughness indexes and their relationship with water erosion PAB
Zangiski,Fernanda; Miquelluti,David José; Bertol,Ildegardis; Ramos,Júlio César.
Abstract: The objective of this work was to express soil roughness through statistical, geostatistical, and fractal indexes, comparing and relating them to soil and water losses in different experimental conditions. The study was conducted from 2012 to 2015, in the municipality of Lages, in the state of Santa Catarina, Brazil, in a completely randomized design with two replicates. Three treatments were evaluated: T1, scarified soil at the end of the ryegrass (Lolium multiflorum) crop cycle after removal of the shoot residue; T2, scarified soil at the end of the vetch (Vicia sativa) crop cycle after removal of the shoot residue; and T3, scarified soil without cultivation and without cover. The heights of the microrelief were read with a surface roughness...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Fractal dimension; Limiting difference; Microrelief; Random roughness.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2018000600756
Registros recuperados: 8
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