Species And Habitat Interactions Of The Gopher Tortoise: A Keystone Species?

Species-species and species-habitat interactions have been demonstrated to be important in influencing diversity across a variety of ecosystems. Despite generalities in the importance of these interactions, appropriate mechanisms to explain them are absent in many systems. In sandhill systems of the southeast U.S., gopher tortoises have been hypothesized to be a crucial species in the maintenance of diversity and function. However, the mechanisms and magnitude in which they influence their communities and habitats have rarely been empirically quantified. I examined how habitat structure influences tortoise abandonment of burrows and how tortoise densities influence nonvolant vertebrate community diversity. Tortoise burrow abandonment is directly influenced by canopy closure, with each percent increase in canopy cover relating to a ~2% increase in the probability of burrow abandonment. In addition, tortoise burrow density was positively correlated with diversity and evenness, but not species richness. This influence was directly proportional to burrow density, supporting a dominance role for this species and rejecting the commonly asserted keystone species mechanism. I also quantified the influence of tortoises in influencing diversity relative to other environmental and habitat variables. Through this research, I have demonstrated that disturbance and habitat structure are important, but diversity responds most to density of burrows in the habitat. These findings demonstrate the intricate relationships interacting to maintaining diversity in sandhill systems. In particular, habitat change leading to declines of gopher tortoises may have drastic negative impacts on vertebrate species diversity

Individual differences in the use of physical dimensions to classify matrix patterns

A method was developed to study individual differences in the classification of matrix patterns which were controlled on five physical dimensions: black, area, second moment of inertia, product of inertia, and matrix grain. The method permitted a test of whether the findings of the study, based on the sample set of patterns, could be generalized to the stimulus domain

Content analysis of principal job descriptions and principal evaluation instruments of K--12 public education in Virginia

Principals are accountable for juggling multiple competing tasks daily. This study explored the degrees of emphasis placed upon leadership and management behaviors of school principals in Virginia by determining the congruence of job descriptions and evaluation instruments with state and professional standards. State expectations were communicated to varying degrees by responding school divisions in both job descriptions and evaluation instruments. School divisions universally expected principals to focus upon instruction and parent and staff communication, while other state responsibilities received less attention. Organizational management that focused on facilities maintenance was communicated as an important responsibility by a majority of school divisions but was not mentioned in state standards. A high level of congruence was found between job descriptions and evaluation instruments for most Virginia state responsibilities. A majority of school divisions\u27 evaluation instruments encompassed professional standards. However, less emphasis was revealed for responsibilities related to the larger society. Implications of this study indicate the need for Virginia school divisions to align job descriptions and evaluation instruments with state standards to support the work of principals, and for Virginia state standards to include major responsibilities required by a majority of school divisions

A Machine-Checked Proof of A State-Space Construction Algorithm

This paper presents the correctness proof of Saturation, an algorithm for generating state spaces of concurrent systems, implemented in the SMART tool. Unlike the Breadth First Search exploration algorithm, which is easy to understand and formalise, Saturation is a complex algorithm, employing a mutually-recursive pair of procedures that compute a series of non-trivial, nested local fixed points, corresponding to a chaotic fixed point strategy. A pencil-and-paper proof of Saturation exists, but a machine checked proof had never been attempted. The key element of the proof is the characterisation theorem of saturated nodes in decision diagrams, stating that a saturated node represents a set of states encoding a local fixed-point with respect to firing all events affecting only the node s level and levels below. For our purpose, we have employed the Prototype Verification System (PVS) for formalising the Saturation algorithm, its data structures, and for conducting the proofs

Automated Verification of Specifications with Typestates and Access Permissions

We propose an approach to formally verify Plural specifications based on access permissions and typestates, by model-checking automatically generated abstract state-machines. Our exhaustive approach captures all the possible behaviors of abstract concurrent programs implementing the specification. We describe the formal methodology employed by our technique and provide an example as proof of concept for the state-machine construction rules. The implementation of a fully automated algorithm to generate and verify models, currently underway, provides model checking support for the Plural tool, which currently supports only program verification via data flow analysis (DFA)

Optical coherence elastography based on inverse compositional Gauss-Newton digital volume correlation with second-order shape function

A digital volume correlation (DVC)-based optical coherence elastography (OCE) method with inverse compositional Gauss-Newton (IC-GN) algorithm and second-order shape function is presented in this study. The systematic measurement errors of displacement and strain from our OCE method were less than 0.2 voxel and 4 × 10−4, respectively. Second-order shape function could better match complex deformation and decrease speckle rigidity-induced error. Compared to conventional methods, our OCE method could track a larger strain range up to 0.095 and reduce relative error by 30-50%. This OCE method has the potential to become an effective tool in characterising mechanical properties of biological tissue

Controlling an Invasive Forest Pest, the Asiatic Oak Weevil (cyrtepistomus castaneus), Using Prescribed Fire

Invasive species are non-native species whose presence is already or is likely to cause harm to the local ecosystem or economy, or human, animal, and plant health (Beck et al, 2006, p.415). The invasive Asiatic oak weevil is the primary leaf-feeding insect on oak trees in the Missouri Ozarks with larvae feeding on the roots of trees and the adults on the leaves (Marquis and Bhatti-Catano, 2017). The goal of this study was to determine if prescribed burns lower the abundance of adult and larval weevils. Eight pairs of 200 m x 200 m plots in the oak-hickory forest at the Tyson Research Station near Eureka, MO were used for the experimental environment. One of each plot pairs were surface-burned in early Spring 2018. In June 2018, mesh emergence traps with jars secured on top were placed under four white and four black oak trees on each plot. From late June-August 2018 the weevils were counted as they emerged and analyzed to determine effects of the sampling date, tree species, aspect, slope, weight, and ultimately weevil density in burned versus unburned plots. Notable differences in the density of weevils on burned vs. unburned plots were observed in favor of the hypothesis. These findings support the need for prescribed fire in the management of Missouri’s forests. References Beck, G. K. Zimmerman, J.D. Schardt, J. Stone, R.R. Lukens, S. Reichard, J. Randall, A.A. Cangelosi, D. Cooper, and J.P. Thompson. 2006. Invasive Species Defined in a Policy Context: Recommendations from the Federal Invasive Species Advisory Committee. Invasive Plant Science and Management 1(4):414-421. Marquis, R. J., & Bhatti-Catano, L. (2017). Impacts of the Asiatic oak weevil (Cyrtepistomus castaneus) on the growth and survivorship of black oak (Quercus velutina) seedlings. Retrieved February 10, 2019, from https://tyson.wustl.edu/allprojects/2017/10/4/impacts of-the-asiatic-oak-weevil-icyrtepistomus-castaneusi-on-the-growth-and-survivorship-of black-oak-iquercus-velutinai-seedling

Automated Verification of Specifications with Typestates and Access Permissions

We propose an approach to formally verify Plural specifications  of concurrent programs based on access permissions and  typestates, by model-checking automatically generated abstract  state-machines. Our approach captures all possible relevant  behaviors of abstract concurrent programs implementing the  specification. We describe the formal methodology employed in  our technique and provide an example as proof of concept for the  state-machine construction rules.  We implemented the fully automated algorithm to generate and  verify models as a freely available plug-in of the Plural tool,  called Pulse.  We tested Pulse on the full specification of a  Multi Threaded Task Server commercial application and showed  that this approach scales well and is efficient in finding  errors in specifications that could not be previously detected  with the Data Flow Analysis (DFA) capabilities of Plural