The Northern Bob-White\u27s winter territory

This bulletin attempts to bring up to date our knowledge o[ individual covey ranges or wintering territories of the bobwhite quail [Colinus virginianus virginianus (Linn.)] (Fig. 1.) It is based upon all of the pertinent and reliable data upon the subject at hand, of whatever origin and whatever degree of previous publication. Pertinence and reliability constitute the sole criteria by which we have attempted to judge the eligibility of data used, whether the data support our principal conclusions or not

The great horned owl and its prey in north-central United States

Along with other predatory species, the great horned owl has been studied in north-central United States, particularly in Iowa and southern Wisconsin localities in which ecological research upon certain prey types has been carried on contemporaneously. After investigation by field and laboratory methods involving experimentation with captive horned owls and observation in nature, it became obvious that the mass data on feeding trends required by the program could be best obtained through pellet studies supplemented by whatever additional techniques would yield information. The horned owl food habits data upon which this bulletin is partly based were gathered largely between 1930 and 1935 and were the product of experience with 84 horned owl nests, examination of 4,815 pellets and 23 food-containing stomachs and records of direct predation. The prey types studied were chiefly upland game birds, waterfowl and fur-bearers, though many other forms were observed incidentally. The general procedure was to continue, so far as feasible, work on predation and population year after year on specific areas and to correlate the data from both; in this way, not only have some of the reasons for pronounced changes in food habits of predators become evident, but a superior background for evaluating effects of predation upon population levels of prey species has also resulted

A randomized trial of a lab-embedded discourse intervention to improve research ethics.

We report a randomized trial of a research ethics training intervention designed to enhance ethics communication in university science and engineering laboratories, focusing specifically on authorship and data management. The intervention is a project-based research ethics curriculum that was designed to enhance the ability of science and engineering research laboratory members to engage in reason giving and interpersonal communication necessary for ethical practice. The randomized trial was fielded in active faculty-led laboratories at two US research-intensive institutions. Here, we show that laboratory members perceived improvements in the quality of discourse on research ethics within their laboratories and enhanced awareness of the relevance and reasons for that discourse for their work as measured by a survey administered over 4 mo after the intervention. This training represents a paradigm shift compared with more typical module-based or classroom ethics instruction that is divorced from the everyday workflow and practices within laboratories and is designed to cultivate a campus culture of ethical science and engineering research in the very work settings where laboratory members interact

Analysing The Role of Virtualisation and Visualisation on Interdisciplinary Knowledge Exchange in Stem Cell Research Processes

Interdisciplinary work is an increasingly frequent and important aspect of scientific research. However, successful knowledge exchange and collaboration between experts is itself a challenging activity with both technical and social components that require consideration. Here, this article analyses the cultural factors involved in interdisciplinary research, specifically in the context of a software programme designed to improve knowledge exchange. The authors undertook an ethnographic study to understand the impact of virtualisation and visualisation on an interdisciplinary research team, working together to develop novel imaging technologies for investigating stem cells. In this discovery-research environment the challenge was to determine the socio-technical effect of an in-house software tool called ProtocolNavigator, which provided a virtual laboratory environment for the team to simulate and map their ‘real-life laboratory’ activities. This display, together with activity icons and a timeline, could be visually analysed and transferred between multiinstitutional researchers in a non-narrative approach. The aim of the work reported here is to provide the first detailed analysis of how software of this type is used in practice, and to analyse this through a robust social science-based perspective. Subsequently this study examines the effectiveness of this virtual laboratory environment on enhancing communication and understanding using a theoretical framework drawing upon three insights from the Sociology of Expertise and Experience: (i) interactional and contributory expertise, (ii) knowledge exchange and interpretative flexibility, and (iii) trading zones. The framework was extended by introducing the notion of material, concept and practice trade at these trading zones with a demonstration of how interactive visualisation of interconnected trading routes can empower interdisciplinary work. The addition of Foucault’s classic account of power found evidence of a panoptical effect due to the augmented visibility of each other’s work. In summary, the article offers a theoretical framework together with novel analysis to determine the influence of introducing tools and approaches designed to enhance interdisciplinary working—particularly in the context of knowledge sharing and trust

Calculation of surface tension via area sampling

We examine the performance of several molecular simulation techniques aimed at evaluation of the surface tension through its thermodynamic definition. For all methods explored, the surface tension is calculated by approximating the change in Helmholtz free energy associated with a change in interfacial area through simulation of a liquid slab at constant particle number, volume, and temperature. The methods explored fall within three general classes: free-energy perturbation, the Bennett acceptance-ratio scheme, and the expanded ensemble technique. Calculations are performed for both the truncated Lennard-Jones and square-well fluids at select temperatures spaced along their respective liquid-vapor saturation lines. Overall, we find that Bennett and expanded ensemble approaches provide the best combination of accuracy and precision. All of the methods, when applied using sufficiently small area perturbation, generate equivalent results for the Lennard-Jones fluid. However, single-stage free-energy-perturbation methods and the closely related test-area technique recently introduced by Gloor et al. [J. Chem. Phys. 123, 134703 (2005)], generate surface tension values for the square-well fluid that are not consistent with those obtained from the more robust expanded ensemble and Bennett approaches, regardless of the size of the area perturbation. Single-stage perturbation methods fail also for the Lennard-Jones system when applied using large area perturbations. Here an analysis of phase-space overlap produces a quantitative explanation of the observed inaccuracy, and shows that the satisfactory results obtained in these cases from the test-area method arise from a cancellation of errors that cannot be expected in general.Comment: 28 pages, 7 figures, to appear in J. Chem. Phys. (07 Nov 2007 issue

Accurate simulation estimates of phase behaviour in ternary mixtures with prescribed composition

This paper describes an isobaric semi-grand canonical ensemble Monte Carlo scheme for the accurate study of phase behaviour in ternary fluid mixtures under the experimentally relevant conditions of prescribed pressure, temperature and overall composition. It is shown how to tune the relative chemical potentials of the individual components to target some requisite overall composition and how, in regions of phase coexistence, to extract accurate estimates for the compositions and phase fractions of individual coexisting phases. The method is illustrated by tracking a path through the composition space of a model ternary Lennard-Jones mixture.Comment: 6 pages, 3 figure

Ultrasensitivity of the Bacillus subtilis sporulation decision

Starving Bacillus subtilis cells execute a gene expression program resulting in the formation of stress-resistant spores. Sporulation master regulator, Spo0A, is activated by a phosphorelay and controls the expression of a multitude of genes, including the forespore- specific sigma factor σF and the mother cell-specific sigma factor σE. Identification of the system-level mechanism of the sporulation decision is hindered by a lack of direct control over Spo0A activity. This limitation can be overcome by using a synthetic system in which Spo0A activation is controlled by inducing expression of phosphorelay kinase KinA. This induction results in a switch-like increase in the number of sporulating cells at a threshold of KinA. Using a combination of mathematical modeling and single-cell microscopy, we investigate the origin and physiological significance of this ultrasensitive threshold. The results indicate that the phosphorelay is unable to achieve a sufficiently fast and ultrasensitive response via its positive feedback architecture, suggesting that the sporulation decision is made downstream. In contrast, activation of σF in the forespore and of σE in the mother cell compartments occurs via a cascade of coherent feed-forward loops, and thereby can produce fast and ultrasensitive responses as a result of KinA induction. Unlike σF activation, σE activation in the mother cell compartment only occurs above the KinA threshold, resulting in completion of sporulation. Thus, ultrasensitive σE activation explains the KinA threshold for sporulation induction. We therefore infer that under uncertain conditions, cells initiate sporulation but postpone making the sporulation decision to average stochastic fluctuations and to achieve a robust population response

Adjusting the melting point of a model system via Gibbs-Duhem integration: application to a model of Aluminum

Model interaction potentials for real materials are generally optimized with respect to only those experimental properties that are easily evaluated as mechanical averages (e.g., elastic constants (at T=0 K), static lattice energies and liquid structure). For such potentials, agreement with experiment for the non-mechanical properties, such as the melting point, is not guaranteed and such values can deviate significantly from experiment. We present a method for re-parameterizing any model interaction potential of a real material to adjust its melting temperature to a value that is closer to its experimental melting temperature. This is done without significantly affecting the mechanical properties for which the potential was modeled. This method is an application of Gibbs-Duhem integration [D. Kofke, Mol. Phys.78, 1331 (1993)]. As a test we apply the method to an embedded atom model of aluminum [J. Mei and J.W. Davenport, Phys. Rev. B 46, 21 (1992)] for which the melting temperature for the thermodynamic limit is 826.4 +/- 1.3K - somewhat below the experimental value of 933K. After re-parameterization, the melting temperature of the modified potential is found to be 931.5K +/- 1.5K.Comment: 9 pages, 5 figures, 4 table