range size

Osteoporosis is a condition of decreased bone mass. This leads to fragile bones which are at an increased risk for fractures, more often, it affects postmenopausal women. In this paper we propose a study of osteoporosis with the fractal dimension. After an introduction to the theory and fractal dimension, we use the box counting method for the segmentation of radiographic images, the study of the influence of range size boxes on the fractal dimension will be investigated, and the correlation between a reference dimension and bone mineral density. Other imaging techniques will be given in order to see the results of the application of the method on these types of images.

Geographic patterns of species richness are influenced by many factors, but the role of shared physiographical and physiological boundaries in relation to range-size distributions has been surprisingly neglected, in spite of the fact that such geometric constraints lead to mid-domain richness peaks even without environmental gradients (the mid-domain effect). Relying on null models, several recent studies have begun to quantify this problem using simulated and empirical data. This approach promises to transform how we perceive geographic variation in diversity, including the long unresolved latitudinal gradient in species richness. The question is not whether geometry affects such patterns, but by how much.

The causes of global variation in species richness have been debated for nearly two centuries with no clear resolution in sight. Competing hypotheses have typically been evaluated with correlative models that do not explicitly incorporate the mechanisms responsible for biotic diversity gradients. Here, we employ a fundamentally different approach that uses spatially explicit Monte Carlo models of the placement of cohesive geographical ranges in an environmentally heterogeneous landscape. These models predict species richness of endemic South American birds (2248 species) measured at a continental scale. We demonstrate that the principal single-factor and composite (species-energy, water-energy and temperature-kinetics) models proposed thus far fail to predict ( r 2 ⩽0.05) the richness of species with small to moderately large geographical ranges (first three range-size quartiles). These species constitute the bulk of the avifauna and are primary targets for conservation. Climate-dri...

Questions: 1) What is the effect of functional type on species’ distribution model performance, and which plant species’ traits explain the most variation? 2) Does model performance vary more as a result of functional type, individual species characteristics, or modeling method?; Location: California’s Southwest Ecoregion, USA; Methods: We developed species distribution models (SDMs) for 45 plant species using four modeling

Abstract: In the US rare and endangered species protection is a public policy responsibility commonly as-cribed to the federal or state governments. We make three related claims: 1) the scale of local and regional land use control and open-space acquisitions matches the range sizes of ...

The New World titi monkeys (Callicebus) are predominantly frugivorous, but there are differences between species in the other components of the diet: species of the C. moloch group [1] supplement their diet with leaves, while C. torquatus uses insects and seeds [2, 3]. In general, although little studied, the titi species endemic to the Atlantic coastal forests of Brazil [4] are thought to be more similar ecologically to the C. moloch group than to C. torquatus [5]. It has also been argued, however, that at least one Atlantic forest species, C. melanochir, resembles C. torquatus in having a larger range size and a higher proportion of fruit in its diet than C. moloch [6, 7]. Here we present new data on the diet of another, poorly known Atlantic forest species, the northern masked titi, C. personatus.

... Nature and Forest (INBO), Kliniekstraat 25, 1070 Brussels, Belgium e-mail: wouter.vanlanduyt@ inbo.be ... plant species, while others benefited from human inter-actions and expanded (VanLanduyt et al. ... atlas data over two or more periods, such as those from the UK (Preston et ...

New Zealand forests grow under highly oceanic climates on an isolated southern archipelago. They experience a combination of historical and environmental factors matched nowhere else. This paper explores whether the New Zealand tree flora also differs systematically from those found in other temperate and island areas. A compilation of traits and distributions from standard floras is used to compare the New Zealand tree flora with those of Europe, North America, Chile, southern Australia, Fiji and Hawaii. New Zealand has a large number of trees (215 species ≥6 m in height). It is more tree-rich than temperate North America and Europe having up to 50% more species at a quadrat scale of 2.5o latitude x 2.5o longitude. However, this richness is due to a greater abundance of small trees (≤15 m in height) and we argue that it is a legacy of allopatric speciation and radiation during the late Neogene (2.5–10 million yrs ago) when the New Zealand landmass was repeatedly split into smaller ...