An Annotated Checklist of the Crayfishes (Decapoda: Cambaridae) of Arkansas

Prior to the present study, 56 species with 3 additional subspecies for a total of 59 different taxa of crayfishes were recognized from Arkansas. We add a single species (Carmel Crayfish, Fallicambarus schusteri) to that list, subtract a documented synonym (Procambarus ferrugenius = Procambarus liberorum), update the classification to better reflect recent phylogenetic insights, and provide an updated annotated checklist of the 59 crayfish taxa of presently known from the state. There are 8 endemic species in Arkansas, including the Bayou Bodcau Crayfish (Bouchardina robisoni), Boston Mountains Crayfish (Cambarus causeyi), Hell Creek Cave Crayfish (C. zophonastes), Jefferson County Crayfish (Creaserinus gilpini), Ouachita Burrowing Crayfish (Fallicambarus harpi), Slenderwrist Burrowing Crayfish (F. petilicarpus), Saline Burrowing Crayfish (F. strawni), and Redspotted Stream Crayfish (Faxonius acares). There are also 2 federally endangered species, the Benton County Cave Crayfish (Cambarus aculabrum) and the Hell Creek Cave Crayfish (C. zophonastes) that inhabit Arkansas karst habitat. We expect that additional species will be included in the list with further DNA analyses

What Next for Chaos Theory? From Metaphor to Phase Space

In the management and social sciences literature, chaos theory has been used primarily as a metaphor to understand organizational phenomena. Using metaphors to understand organizations is a novel idea that has gained much acceptance, thanks to the pioneering work of Morgan (1986). However, chaos theory\u27s value as a metaphor has been overused and offers little that cannot already be explained using existing theories and frameworks. Because chaos theory is a mathematical theory, we believe its mathematical principles offer the greatest application to the management literature. In this paper, we offer the use of phase space, a tool of chaos theory, as a way to analyze firm performance

In Pursuit of Crisis Readiness: An Examination of Managerial Characteristics, Firm Size, Industry Domain and Strategic Type within the Miles and Snow Framework

A crisis refers to an unpredictable event that can seriously threaten an organization. Crisis readiness is an integral part of the crisis management process and refers to the level of preparedness an organization possesses in response to a potential catastrophic event. Findings from a survey of 275 managers in the United States revealed that top managers with production/engineering and general management backgrounds reported higher degrees of crisis readiness capabilities than did their counterparts with other backgrounds. Likewise, higher levels of crisis readiness were reported in larger, manufacturing organizations than in smaller, service organizations

Perestroikas of Shocks and Singularities of Minimum Functions

The shock discontinuities, generically present in inviscid solutions of the forced Burgers equation, and their bifurcations happening in the course of time (perestroikas) are classified in two and three dimensions -- the one-dimensional case is well known. This classification is a result of selecting among all the perestroikas occurring for minimum functions depending generically on time, the ones permitted by the convexity of the Hamiltonian of the Burgers dynamics. Topological restrictions on the admissible perestroikas of shocks are obtained. The resulting classification can be extended to the so-called viscosity solutions of a Hamilton--Jacobi equation, provided the Hamiltonian is convex.Comment: 20 pages, 8 figures, 3 tables; my e-mail: [email protected]

Claw asymmetry in crabs: approaching an old issue from a new point of view

Abstract Crabs are considered exceptional examples of antisymmetry resulting from the phenomenon of heterochely. Here we investigate morphometrically both the size and the shape of heterochely in 28 crab species, distributed unequally along a brachyuran phylogeny. We address the importance of investigating claw size and shape for interspecific comparisons by linking geometric morphometric outputs to phylogenetic data for 134 brachyuran species. New indices introduced as new sexual dimorphic characters of size and shape, namely heterometry (right chela size/left chela size) and heteromorphy (Procrustes distance between right and left chelae shape), revealed sexually dimorphic differences in diverse crab species. We demonstrate that both size and shape heterochely occur amongst the examined species, but there are no ecological correlations. Our study demonstrates that claw similarity between two or more species was due mainly to phylogenetic relatedness rather than ecological convergence, suggesting that claw morphological features could be useful morphological markers in phylogenetic studies. Although further investigation is needed, this study represents one of the first to thoroughly analyse the origin and evolution of heterochely within the Brachyura clade