Evolution of Sexual Dimorphism and Male Dimorphism in the Expression of Beetle Horns: Phylogenetic Evidence for Modularity, Evolutionary Lability, and Constraint

Beetle horns are enlarged outgrowths of the head or thorax that are used as weapons in contests over access to mates. Horn development is typically confined to males (sexual dimorphism) and often only to the largest males (male dimorphism). Both types of dimorphism result from endocrine threshold mechanisms that coordinate cell proliferation near the end of the larval period. Here, we map the presence/absence of each type of dimorphism onto a recent phylogeny for the genus Onthophagits (Coleoptera: Scarabaeidae) to explore how horn development has changed over time. Our results provide empirical support for several recent predictions regarding the evolutionary lability of developmental thresholds, including uncoupled evolution of alternative phenotypes and repeated fixation of phenotypes. We also report striking evidence of a possible developmental constraint. We show that male dimorphism and sexual dimorphism map together on the phylogeny; whenever small males have horns, females also have horns (and vice versa). We raise the possibility that correlated evolution of these two phenomena results from a shared element in their endocrine regulatory mechanisms rather than a history of common selection pressures. These results illustrate the type of insight that can be gained only from the integration of developmental and evolutionary perspectives

Low Frequency Vibration Approach for Assessing Performance of Wood Floor Systems1

The primary means of inspecting buildings and other structures is to evaluate each structure member individually. This is a time-consuming and expensive process, particularly if sheathing or other covering materials must be removed to access the structural members. The objective of this study was to determine if a low frequency vibration method could be used to effectively assess the structural performance of wood floors as component systems. Twelve wood floors were constructed with solid sawn wood joists in the laboratory and tested with both vibration and static load methods. The results indicated that the forced vibration method was capable of measuring the fundamental natural frequency (bending mode) of the wood floors investigated. An analytical model derived from the flexural beam theory was found to fit the physics of the floor structures and can be used to correlate natural frequency to section modulus (EI product) of the floor systems

Threshold Evolution in Exotic Populations of a Polyphenic Beetle

Polyphenic development is thought to play an important role in the evolution of phenotypic diversity and morphological novelties, yet the evolution of polyphenisms has rarely been documented in natural populations. Here we compare the morphologies of male dung beetles (Onthophagus taurus; Coleoptera: Scarabaeidae) from populations introduced to Australia and the eastern United States. Males in this species express two alternative morphologies in response to larval feeding conditions. Males encountering favourable conditions grow larger than a threshold body size and develop a pair of horns on their heads, whereas males that encounter poor conditions do not reach this threshold size and remain hornless. Australian and US populations did not differ in overall body size ranges, but exhibited significant differences in the location of the critical body size threshold that separates alternative male morphs. Australian males remained hornless at much larger body sizes than males in US populations, resulting in substantial and significant differences in the average body size-horn length allometry between exotic populations, as well as significant differences in morph ratios. The phenotypic divergence observed between field populations was maintained in laboratory populations after two generations under identical environmental conditions, suggesting a genetic basis to allometric divergence in these populations. Divergence between exotic O. taurus populations was of a magnitude and kind typically observed between species. We use our results to examine potential causes of allometric divergence in onthophagine beetles, and discuss the evolutionary potential of threshold traits and polyphenic development in the origin of morphological and behavioural diversity

An analysis of likes and dislikes for history and geography of 3360 sixth grade children

Thesis (Ed.M.)--Boston Universit

Temporal and Geospatial Trends of Pediatric Cancer Incidence in Nebraska Over a 24-Year Period

BACKGROUND: Data from the Surveillance, Epidemiology, and End Results (SEER) revealed that the incidence of pediatric cancer in Nebraska exceeded the national average during 2009-2013. Further investigation could help understand these patterns. METHODS: This retrospective cohort study investigated pediatric cancer (0-19 years old) age adjusted incidence rates (AAR) in Nebraska using the Nebraska Cancer Registry. SEER AARs were also calculated as a proxy for pediatric cancer incidence in the United States (1990-2013) and compared to the Nebraska data. Geographic Information System (GIS) mapping was also used to display the spatial distribution of cancer in Nebraska at the county level. Finally, location-allocation analysis (LAA) was performed to identify a site for the placement of a medical center to best accommodate rural pediatric cancer cases. RESULTS: The AAR of pediatric cancers was 173.3 per 1,000,000 in Nebraska compared to 167.1 per 1,000,000 in SEER. The AAR for lymphoma was significantly higher in Nebraska (28.1 vs. 24.6 per 1,000,000; p = 0.009). For the 15-19 age group, the AAR for the 3 most common pediatric cancers were higher in Nebraska (p \u3c 0.05). Twenty-three counties located \u3e2 h driving distance to care facilities showed at least a 10% higher incidence than the overall state AAR. GIS mapping identified a second potential treatment site that would alleviate this geographic burden. CONCLUSIONS: Regional differences within Nebraska present a challenge for rural populations. Novel use of GIS mapping to highlight regional differences and identify solutions for access to care issues could be used by similar states

funcGNN: A Graph Neural Network Approach to Program Similarity

Program similarity is a fundamental concept, central to the solution of software engineering tasks such as software plagiarism, clone identification, code refactoring and code search. Accurate similarity estimation between programs requires an in-depth understanding of their structure, semantics and flow. A control flow graph (CFG), is a graphical representation of a program which captures its logical control flow and hence its semantics. A common approach is to estimate program similarity by analysing CFGs using graph similarity measures, e.g. graph edit distance (GED). However, graph edit distance is an NP-hard problem and computationally expensive, making the application of graph similarity techniques to complex software programs impractical. This study intends to examine the effectiveness of graph neural networks to estimate program similarity, by analysing the associated control flow graphs. We introduce funcGNN, which is a graph neural network trained on labeled CFG pairs to predict the GED between unseen program pairs by utilizing an effective embedding vector. To our knowledge, this is the first time graph neural networks have been applied on labeled CFGs for estimating the similarity between high-level language programs. Results: We demonstrate the effectiveness of funcGNN to estimate the GED between programs and our experimental analysis demonstrates how it achieves a lower error rate (0.00194), with faster (23 times faster than the quickest traditional GED approximation method) and better scalability compared with the state of the art methods. funcGNN posses the inductive learning ability to infer program structure and generalise to unseen programs. The graph embedding of a program proposed by our methodology could be applied to several related software engineering problems (such as code plagiarism and clone identification) thus opening multiple research directions.Comment: 11 pages, 8 figures, 3 table

Recruitment in Degraded Marine Habitats: A Spatially Explicit, Individual-Based Model for Spiny Lobster

Coastal habitats that serve as nursery grounds for numerous marine species are badly degraded, yet the traditional means of modeling populations of exploited marine species handle spatiotemporal changes in habitat characteristics and life history dynamics poorly, if at all. To explore how nursery habitat degradation impacts recruitment of a mobile, benthic species, we developed a spatially explicit, individual-based model that describes the recruitment of Caribbean spiny lobster (Panulirus argus) in the Florida Keys, where a cascade of environmental disturbances has reconfigured nursery habitat structure. In recent years, the region has experienced a series of linked perturbations, among them, seagrass die-offs, cyanobacteria blooms, and the mass mortality of sponges. Sponges are important shelters for juvenile spiny lobster, an abundant benthic predator that also sustains Florida\u27s most valuable fishery. In the model, we simulated monthly settlement of individual lobster postlarvae and the daily growth, mortality, shelter selection, and movement of individual juvenile lobsters on a spatially explicit grid of habitat cells configured to represent the Florida Keys coastal nursery. Based on field habitat surveys, cells were designated as either seagrass or hard-bottom, and hard-bottom cells were further characterized in terms of their shelter- and size-specific lobster carrying capacities. The effect of algal blooms on sponge mortality, hence lobster habitat structure, was modeled based on the duration of exposure of each habitat cell to the blooms. Ten-year simulations of lobster recruitment with and without algal blooms suggest that the lobster population should be surprisingly resilient to massive disturbances of this type. Data not used in model development showed that predictions of large changes in lobster shelter utilization, yet small effects on recruitment in response to blooms, were realistic. The potentially severe impacts of habitat loss on recruitment were averted by compensatory changes in habitat utilization and mobility by larger individuals, coupled with periods of fortuitously high larval settlement. Our model provides an underutilized approach for assessing habitat effects on open populations with complex life histories, and our results illustrate the potential pitfalls of relying on intuition to infer the effects of habitat perturbations on upper trophic levels

Bostonia. Volume 4

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

Color Transformations for the 2MASS Second Incremental Data Release

Transformation equations are presented to convert colors and magnitudes measured in the AAO, ARNICA, CIT, DENIS, ESO, LCO (Persson standards), MSSSO, SAAO, and UKIRT photometric systems to the photometric system inherent to the 2MASS Second Incremental Data Release. The transformations have been derived by comparing 2MASS photometry with published magnitudes and colors for stars observed in these systems. Transformation equations have also been derived indirectly for the Bessell & Brett (1988) and Koornneef (1983) homogenized photometric systems.Comment: To appear in AJ, May 200

Active and covert infections of cricket Iridovirus and Acheta domesticus Densovirus in reared Gryllodes sigillatus crickets

Interest in developing food, feed, and other useful products from farmed insects has gained remarkable momentum in the past decade. Crickets are an especially popular group of farmed insects due to their nutritional quality, ease of rearing, and utility. However, production of crickets as an emerging commodity has been severely impacted by entomopathogenic infections, about which we know little. Here, we identified and characterized an unknown entomopathogen causing mass mortality in a lab-reared population of Gryllodes sigillatus crickets, a species used as an alternative to the popular Acheta domesticus due to its claimed tolerance to prevalent entomopathogenic viruses. Microdissection of sick and healthy crickets coupled with metagenomics-based identification and real-time qPCR viral quantification indicated high levels of cricket iridovirus (CrIV) in a symptomatic population, and evidence of covert CrIV infections in a healthy population. Our study also identified covert infections of Acheta domesticus densovirus (AdDNV) in both populations of G. sigillatus. These results add to the foundational research needed to better understand the pathology of mass-reared insects and ultimately develop the prevention, mitigation, and intervention strategies needed for economical production of insects as a commodity