A Comparison of Anuran Species Richness Between Primary and Secondary Forest in São Francisco do Pará

Deforestation in the Amazon has become a serious conservation issue. The process of destruction of primary forest results in the creation of secondary forest that differs from primary forest in a number of important ways. Anurans (frogs and toads) are one group that may be affected by the loss of primary forest and creation of secondary forest areas, and are an important focus for conservation efforts. Previous studies on anuran reactions to loss of primary forest have been few and inconclusive. This study examined anuran species richness in an area of primary and secondary forest in order to determine whether the successional state of a forest affects the number of species and the types of species present in each area. The methods of audio-strip transects and visual encounter surveys were used to sample anuran species richness in primary and secondary forest in the municipality of São Francisco do Pará, Brazil. A total of 16 species were found in 28 man-hours of sampling, of which ten were found in the primary forest and eight in the secondary forest, resulting in no significant difference between the two forest areas in terms of species numbers. There was however a very low index of similarity between the two sites, suggesting that, although the total number of species was similar, the sites differed in terms of which species were present. Thus, anurans may be affected by the increasing destruction of primary forest and its replacement by secondary forest, and this must be kept in mind for future conservation efforts

[μ-3,3′-Bis(tri­hydro­bor­yl)[3]ferroceno­phane]bis­(chlorido­zirconocene)

The title compound, [FeZr2(C5H5)4Cl2(C13H18B2)], is a heteronuclear complex that consists of a [3]ferrocenophane moiety substituted at each cyclo­penta­dienyl (Cp) ring by a BH3 group; the BH3 group is bonded via two H atoms to the Zr atom of the zirconocene chloride moiety in a bidentate fashion. The two Cp rings of the [3]ferrocenophane moiety are aligned at a dihedral angle of 8.9 (4)° arising from the strain of the propane-1,3-diyl bridge linking the two Cp rings. [One methyl­ene group is disordered over two positions with a site-occupation factor of 0.552 (18) for the major occupied site.] The dihedral angles between the Cp rings at the two Zr atoms are 50.0 (3) and 51.7 (3)°. The bonding Zr(...)H distances are in the range 1.89 (7)–2.14 (7) Å. As the two Cp rings of the ferrocene unit are connected by an ansa bridge, the two Zr atoms approach each other at 6.485 (1) Å. The crystal packing features C—H(...)Cl inter­actions

Emergence of the mitochondrial reticulum from fission and fusion dynamics

Mitochondria form a dynamic tubular reticulum within eukaryotic cells. Currently, quantitative understanding of its morphological characteristics is largely absent, despite major progress in deciphering the molecular fission and fusion machineries shaping its structure. Here we address the principles of formation and the large-scale organization of the cell-wide network of mitochondria. On the basis of experimentally determined structural features we establish the tip-to-tip and tip-to-side fission and fusion events as dominant reactions in the motility of this organelle. Subsequently, we introduce a graph-based model of the chondriome able to encompass its inherent variability in a single framework. Using both mean-field deterministic and explicit stochastic mathematical methods we establish a relationship between the chondriome structural network characteristics and underlying kinetic rate parameters. The computational analysis indicates that mitochondrial networks exhibit a percolation threshold. Intrinsic morphological instability of the mitochondrial reticulum resulting from its vicinity to the percolation transition is proposed as a novel mechanism that can be utilized by cells for optimizing their functional competence via dynamic remodeling of the chondriome. The detailed size distribution of the network components predicted by the dynamic graph representation introduces a relationship between chondriome characteristics and cell function. It forms a basis for understanding the architecture of mitochondria as a cell-wide but inhomogeneous organelle. Analysis of the reticulum adaptive configuration offers a direct clarification for its impact on numerous physiological processes strongly dependent on mitochondrial dynamics and organization, such as efficiency of cellular metabolism, tissue differentiation and aging

Aggressive calling in treefrogs

Title from PDF of title page (University of Missouri--Columbia, viewed on May 30, 2012).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. H. Carl GerhardtVita.Ph. D. University of Missouri-Columbia 2011."December 2011"Acoustic communication plays a major role in many of the social activities of frogs. A great deal is known about communication in some contexts, such as mate choice. Aggressive communication, however, has received little attention in frogs. Most frog species produce some kind of aggressive vocalization. These aggressive calls are often given in the context of defense of territories or temporary calling spaces. Little is known about how aggressive calls are used to mediate these interactions. In particular, the communicative significance of aggressive calls, in terms of how assessment proceeds via aggressive calling, is unknown. The aim of my dissertation was to document the behavioral significance of aggressive calling behavior in two treefrog species. In Dendropsophus ebraccatus, a Neotropical treefrog, I examined i) the plasticity of the aggressive response; ii) the effects of multiple competitors and a changing social environment on aggressive calling; and iii) the importance of aggressive calls in competitive call timing interactions. I found that males are highly responsive to aggressive calls and that the aggressive call appears to function primarily to regulate competitive call timing interactions. In the gray treefrog Hyla versicolor, a common North American species, I staged interactions between males in order to examine the determinants of success and the level of escalation in contests. I specifically compared aggressive call characteristics of winners and losers of different types of aggressive interactions to determine whether or not assessment of aggressive calls may play a role in determining contest outcome. I found that body size played little role in determining the outcome of contests. However, certain characteristics of aggressive calls, particularly those that are likely related to energetic expenditure, were important in determining the eventual winner and loser of contests and are likely involved in competitor assessment.Includes bibliographical reference

Cognition in contests: mechanisms, ecology, and evolution

Animal contests govern access to key resources and are a fundamental determinant of fitness within populations. Little is known about the mechanisms generating individual variation in strategic contest behavior or what this variation means for population level processes. Cognition governs the expression of behaviors during contests, most notably by linking experience gained with decision making, but its role in driving the evolutionary ecological dynamics of contests is only beginning to emerge. We review the kinds of cognitive mechanisms that underlie contest behavior, emphasize the importance of feedback loops and socio-ecological context, and suggest that contest behavior provides an ideal focus for integrative studies of phenotypic variation

Towards Integrated Variant Management in Global Software Engineering: An Experience Report

In the automotive domain, customer demands and market constraints are progressively realized by electric/ electronic components and corresponding software. Variant traceability in SPL is crucial in the context of different tasks, like change impact analysis, especially in complex global software projects. In addition, traceability concepts must be extended by partly automated variant configuration mechanisms to handle restrictions and dependencies between variants. Such variant configuration mechanism helps to reduce complexity when configuring a valid variant and to establish an explicit documentation of dependencies between components. However, integrated variant management has not been sufficiently addressed so far. Especially, the increasing number of software variants requires an examination of traceable and configurable software variants over the software lifecycle. This paper emphasizes variant traceability achievements in a large global software engineering project, elaborates existing challenges, and evaluates an industrial usage of an integrated variant management based on experiences

Considering Social Distance as an Influence Factor in the Process of Process Modeling

Enterprise repositories comprise numerous business process models either created by in-house domain experts or external business analysts. To enable a widespread use of these process models, high model quality (e.g., soundness) as well as a sufficient level of granularity are crucial. Moreover, they shall reflect the actual business processes properly. Existing modeling guidelines target at creating correct and sound process models, whereas there is only little work dealing with cognitive issues influencing model creation by process designers. This paper addresses this gap and presents a controlled experiment investigating the construal level theory in the context of process modeling. In particular, we investigate the influence the social distance of a process designer to the modeled domain has on the creation of process models. For this purpose, we adopt and apply a gamification approach, which enables us to show significant differences between low and high social distance with respect to the quality, granularity, and structure of the created process models. The results obtained give insights into how enterprises shall compose teams for creating and evolving process models

An Approach to Detect the Origin and Distribution of Software Defects in an Evolving Cyber-Physical System

Cyber-Physical Systems (CPS) are usually developed by an incremental approach. A changing environment like demanding user requirements or legislation amendments lead often to multiple development paths in an evolving CPS. Hence, software variability plays an increasingly important role adapting the characteristics of such CPS to different contexts. This paper focuses on software variability realized through a Software Product Line (SPL) more specifically. Thereby, variability and evolution are usually managed in different tools. However with respect to software defects, a holistic handling of variability and evolution is necessary to ensure a reliable software defect removal. Particularly, detecting software defects in different evolution stages and derived variants is ordinary, but complex and error-prone. To close the gap between variability and evolution, this paper presents a systematic approach to combine both disciplines. In particular, we apply existing variant management techniques in combination with software configuration management methods to determine a software defect's origin and distribution in an evolving SPL. We apply our approach to a CPS from the automotive domain to show its industrial relevance and usefulness