Multiple differences in calling songs and other traits between solitary and gregarious Mormon crickets from allopatric mtDNA clades

The Linnaean Society, The British Ecological Society, The Russell Trust (St. Andrews), The Orthopterists' Society and an NSERC (Canada) grant to DTG. Gordon S. Brown provided assistance with digital imaging and morphological measurements.Background: In acoustic species, traits such as male calling song are likely to diverge quickly between allopatric populations due to sexual selection, and divergence in parameters such as carrier frequency, chirp structure, and other important song characters can influence sexual isolation. Here we make use of two forms of Mormon crickets to examine differences in a broad suite of traits that have the potential to influence speciation via sexual isolation. Mormon crickets in "gregarious" populations aggregate into dense migratory bands, and females are the sexually competitive Fsex ( sex- role reversal). There is also a non-outbreak "solitary" form. These two forms are largely but not perfectly correlated with a significant mtDNA subdivision within the species that is thought to have arisen in allopatry. Combined information about multiple, independently evolving traits, such as morphology and structural and behavioural differences in calling song, provides greater resolution of the overall differences between these allopatric populations, and allows us to assess their stage of divergence. We test two predictions, first that the forms differ in song and second that gregarious males are more reluctant to sing than solitary males due to sex role reversal. We also tested for a difference in the relationship between the size of the forewing resonator, the mirror, and carrier frequency, as most models of sound production in crickets indicate that mirror size should predict carrier frequency. Results: Multivariate analyses showed that solitary and gregarious individuals from different populations representing the two mtDNA clades had almost non-overlapping distributions based on multiple song and morphological measurements. Carrier frequency differed between the two, and gregarious males were more reluctant to sing overall. Mirror size predicted carrier frequency; however, the relationship between mirror size and surface area varied between solitary and gregarious forms, suggesting that factors above and beyond mirror size contribute to carrier frequency. Conclusion: The two clades of Mormon crickets differ in a broad suite of independent traits that probably justify subspecies status ( the two can successfully mate so may not be reproductively isolated). However, our results emphasize the importance of carefully distinguishing the ultimate causation of differences between traits used to delineate species or subspecies boundaries.Publisher PDFPeer reviewe

The feasibility of a cognitive behavioural therapy group for men with mild/moderate cognitive impairment

Memory aid groups have often been used as a method for teaching mnemonic strategies to older adults in early stages of dementia. This study describes the use of CBT to address unhelpful memory-related beliefs in three older men with mild/moderate dementia and associated low mood or anxiety. The members were able to participate and engage in the sessions, and changes in behaviour, cognition and affect were monitored over the course of a 7 week group intervention. Recommendations are made for further research

Predicting Category Intuitiveness With the Rational Model, the Simplicity Model, and the Generalized Context Model

Naïve observers typically perceive some groupings for a set of stimuli as more intuitive than others. The problem of predicting category intuitiveness has been historically considered the remit of models of unsupervised categorization. In contrast, this article develops a measure of category intuitiveness from one of the most widely supported models of supervised categorization, the generalized context model (GCM). Considering different category assignments for a set of instances, the authors asked how well the GCM can predict the classification of each instance on the basis of all the other instances. The category assignment that results in the smallest prediction error is interpreted as the most intuitive for the GCM—the authors refer to this way of applying the GCM as “unsupervised GCM.” The authors systematically compared predictions of category intuitiveness from the unsupervised GCM and two models of unsupervised categorization: the simplicity model and the rational model. The unsupervised GCM compared favorably with the simplicity model and the rational model. This success of the unsupervised GCM illustrates that the distinction between supervised and unsupervised categorization may need to be reconsidered. However, no model emerged as clearly superior, indicating that there is more work to be done in understanding and modeling category intuitiveness

Evaluating Interaction Techniques in an Interactive Workspace: Comparing the Effectiveness of a Textual Interface, Virtual Paths Interface, and ARIS

ARIS is an interface that enables users to visually relocate applications and redirect input among myriad devices in an interactive workspace. While we previously claimed that ARIS is more effective than other interfaces for performing these tasks, this work seeks to empirically validate our claim. We compared the use of ARIS to an interaction design of a text-based and virtual paths interface for relocating applications and redirecting input in an interactive workspace. Results show that (i) users can relocate applications and redirect input faster with ARIS than a text-based interface, (ii) users commit fewer errors with ARIS than a text-based interface, (iii) users experience less workload and are more satisfied with ARIS than a text-based interface, and (iv) ARIS was comparable to the use of a virtual paths interface. ARIS is more effective than an interaction design that requires a user to mentally map and select textual identifiers, while supporting functionality beyond that of a virtual paths interface

Planning a DSN support section technical library

The planning procedure being used to establish a technical library for the Deep Space Network support section is described. The inventory and survey methods employed are described and the preliminary results of these methods are discussed

Studies of low-energy ionic collisions Final report, 1 Oct. 1965 - 30 Sep. 1967

Ionic-molecular collisions, and collision induced dissociation of ion

Optimal Investment with Lumpy Costs

In this paper we solve a continuous-time model of investment with uncertainty, irreversibility and a broad class of lumpy adjustment costs. In addition to being general, our solution is quite tractable and intuitive. We show that, in contrast to standard results, the marginal value of capital jumps when investment is undertaken. We also find that firms facing higher uncertainty let their capital stock depreciate further before they invest, but increase their capital by a similar proportion once they do invest. We extend both the user cost and q theories of investment to incorporate lumpy investment. We confirm that with lumpy investment, a variant of Tobin's q can be a better predictor of investment than marginal q.

A Smoothed-Distribution Form of Nadaraya-Watson Estimation

Given observation-pairs (xi ,yi ), i = 1,...,n , taken to be independent observations of the random pair (X ,Y), we sometimes want to form a nonparametric estimate of m(x) = E(Y/ X = x). Let YE have the empirical distribution of the yi , and let (XS ,YS ) have the kernel-smoothed distribution of the (xi ,yi ). Then the standard estimator, the Nadaraya-Watson form mNW(x) can be interpreted as E(YE?XS = x). The smoothed-distribution estimator ms (x)=E(YS/XS = x) is a more general form than  mNW (x) and often has better properties. Similar considerations apply to estimating Var(Y/X = x), and to local polynomial estimation. The discussion generalizes to vector (xi ,yi ).nonparametric regression, Nadaraya-Watson, kernel density, conditional expectation estimator, conditional variance estimator, local polynomial estimator

Rotorcraft digital advanced avionics system (RODAAS) functional description

A functional design of a rotorcraft digital advanced avionics system (RODAAS) to transfer the technology developed for general aviation in the Demonstration Advanced Avionics System (DAAS) program to rotorcraft operation was undertaken. The objective was to develop an integrated avionics system design that enhances rotorcraft single pilot IFR operations without increasing the required pilot training/experience by exploiting advanced technology in computers, busing, displays and integrated systems design. A key element of the avionics system is the functionally distributed architecture that has the potential for high reliability with low weight, power and cost. A functional description of the RODAAS hardware and software functions is presented