Understanding of spatiotemporal patterns arising in invasive species spread is necessary for successful management and control of harmful species, and mathematical modeling is widely recognized as a powerful research tool to achieve this goal. The conventional view of the typical invasion pattern as a continuous population traveling front has been recently challenged by both empirical and theor...

Horn's model is generalized to state that the "optimal" pattern o f distribution for foragerswill correlate with the degree o f resource patchiness; in particular (1) where resource attributes are less patchy, the "optimal" distribution for foragers is to be dispersed, and (2) where resource attributes are more patchy, the "optimal" distribution for foragers is to be aggregated. "Optimality" is...

BACKGROUND: The purpose of the present correlative immunohistochemical study was to assess the utility of cytokeratin (CK7 and CK20) expression in the diagnosis of short-segment Barrett esophagus, particularly its efficacy in differentiating Barrett mucosa from intestinal metaplasia of the gastric cardia and corpus. METHODS: Two groups of endoscopic biopsy specimens were examined, including 20 ...

Hair loss is an uncommon manifestation of secondary syphilis. Its clinical manifestations include diffuse effluvium or patchy ‘moth-eaten’ pattern of alopecia. Although syphilitic alopecia is non-scarring hair loss often associated with other mucocutaneous lesions of secondary syphilis, it might well be the only presenting symptom of syphilis. Secondary syphilis was diagnosed in ten homosexual ...

Alopecia areata is a common cause of noncicatricial alopecia that occurs in a patchy, confluent or diffuse pattern. It may occur as a single, self-limiting episode or may recur at varying intervals over many years. The association of alopecia areata with localized vitiligo has not been reported. The association of alopecia areata with localized vitiligo in the same patient is documented here; i...

Vandermeer and Perfecto (Reports, 17 February 2006, p. 1000) reported a general power law pattern in the distribution of a common agricultural pest. However, there is an exact analytical solution for the expected cluster distribution under the proposed null model of density-independent growth in a patchy landscape. Reanalysis of the data shows that the system is not in a critical state but conf...

Protein complexes called rosettasomes self-assemble in solution to form large-scale filamentous and planar structures. The relative abundance of these aggregates varies abruptly with environmental conditions and sample composition. Our simulations of a model of patchy nanoparticles can reproduce this sharp crossover, but only if particles are allowed to switch between two internal states favori...