Response to comments on "Differential Sensitivity to Human Communication in Dogs, Wolves, and Human Infants."

The comments by Fiset and Marshall-Pescini et al. raise important methodological issues and propose alternative accounts for our finding of perseverative search errors in dogs. Not denying that attentional processes and local enhancement are involved in such object search tasks, we provide here new evidence and argue that dogs’ behavior is affected by a combination of factors, including specific susceptibility to human communicative signals

Development of a comprehensive decision making framework for power projects in New South Wales (NSW)

University of Technology Sydney. Faculty of Engineering and Information Technology.In the backdrop of emerging concerns about sustainability, the contribution of electricity generation to sustainability, the complexity of power projects, and the narrowness of existing decision approaches for selecting power projects – this research develops a comprehensive decision-making framework that can be applied to select power projects for meeting future electricity needs in NSW. This framework is based on Multi-Attribute Decision Analysis (Analytical Hierarchy Process). This framework will assist with complex decisions regarding projects typified by multiple objectives, multiple decision makers, multiple attributes, conflicts, and socio-economic concerns. The appropriateness of this framework is established in this research in terms of its ability to assist with project choices (from among several alternatives), to meet medium (2035) and long term (2050) electricity needs of NSW, in a sustainable manner. The backdrop for the application of this approach is provided by five scenarios, representing alternative technological pathways, energy & environmental and socio-political settings. Fourteen attributes, reflecting major areas of concern relating to economic, environmental, technical, and socio-political issues are considered, guided by literature review and expert opinion. The overall ranking for each alternative is developed on the basis of, first, assessing the economic, environmental, and social impacts of the alternatives; second, incorporating decision makers’ (expert) preferences for selected attributes, through a pair-wise comparison of various attributes; next, developing a weighted average across all attributes. These individual scenario rankings are then used to compare alternatives represented by various scenarios. The analysis suggest that, overall, the BAU scenario, representing a continuation of existing trends in generation-mix is likely to be the most detrimental scenario for achieving sustainable outcomes in NSW, as it will result in highest levels of levelized cost, GHG emissions, total waste, air pollution, visual impact, water use, resource (fuel) use, severe accidents; and lowest levels of new jobs, and political and social acceptance. The best option in the medium term (2035) for NSW will be the HR-1 scenario (40% share of renewables, with nuclear), as it will result in the highest levels of new jobs, political and social acceptance; and lowest levels of levelized cost, GHG emissions, total waste, air pollution, resource (fuel) use. The best option in the long term (2050) for NSW will be the HR-2 scenario (80% share of renewables, without nuclear), as it will result in the highest levels of new jobs, political and social acceptance; lowest levels of total waste, water use, severe accidents; and moderate levels of levelized cost, air pollution, water and resource use. It is interesting to note the change of preference from HR-1 scenario in the medium term, to HR-2 scenario in the long term, as informed by trade-offs between various attributes. The above insights clearly demonstrate the usefulness of the proposed framework for making complex decisions about power projects

Molecular Gas Properties of the Giant Molecular Cloud Complexes in the Arms and Inter-arms of the Spiral Galaxy NGC 6946

Combining observations of multiple CO lines with radiative transfer modeling is a very powerful tool to investigate the physical properties of the molecular gas in galaxies. Using new observations as well as literature data, we provide the most complete CO ladders ever generated for eight star-forming regions in the spiral arms and inter-arms of the spiral galaxy NGC 6946, with observations of the CO(1-0), CO(2-1), CO(3-2), CO(4-3), CO(6-5), 13CO(1-0) and 13CO(2-1) transitions. For each region, we use the large velocity gradient assumption to derive beam-averaged molecular gas physical properties, namely the gas kinetic temperature (T_K), H2 number volume density n(H2) and CO number column density N(CO). Two complementary approaches are used to compare the observations with the model predictions: chi-square minimisation and likelihood. The physical conditions derived vary greatly from one region to the next: T_K=10-250 K, n(H2)=10^2.3-10^7.0 cm^-3 and N(CO)=10^15.0-10^19.3 cm^-2. The spectral line energy distribution (SLED) of some of these extranuclear regions indicates a star-formation activity that is more intense than that at the centre of our own Milky Way. The molecular gas in regions with a large SLED turnover transition (J_max>4) is hot but tenuous with a high CO column density, while that in regions with a low SLED turnover transition (J_max<=4) is cold but dense with a low CO column density. We finally discuss and find some correlations between the physical properties of the molecular gas in each region and the presence of young stellar population indicators (supernova remnants, HII regions, HI holes, etc.)Comment: 23 pages, 11 figures, MNRAS, Accepte

ISM chemistry in metal rich environments: molecular tracers of metallicity

In this paper we use observations of molecular tracers in metal rich and alpha-enhanced galaxies to study the effect of abundance changes on molecular chemistry. We selected a sample of metal rich spiral and star bursting objects from the literature, and present here new data for a sample of early-type galaxies (ETGs). We conducted the first survey of CS and methanol emission in ETGs, detecting 7 objects in CS, and 5 in methanol emission. We find evidence to support the hypothesis that CS is a better tracer of dense star-forming gas than HCN. We suggest that the methanol emission in these sources is driven by dust mantle destruction due to ionisation from high mass star formation, but cannot rule out shocks dominating in some sources. The derived source averaged CS/methanol column densities and rotation temperatures are similar to those found in normal spiral and starburst galaxies, suggesting dense clouds are little affected by the differences between galaxy types. Finally we used the total column density ratios for our galaxy samples to show for the first time that some molecular tracers do seem to show systematic variations that appear to correlate with metallicity, and that these variations roughly match those predicted by chemical models. Using this fact, the chemical models of Bayet et al. (2012b), and assumptions about the optical depth we are able to roughly predict the metallicity of our spiral and ETG sample, with a scatter of ~0.3 dex. We provide the community with linear approximations to the relationship between the HCN and CS column density ratio and metallicity. Further study will clearly be required to determine if this, or any, molecular tracer can be used to robustly determine gas-phase metallically, but that a relationship exists at all suggests that in the future it may be possible to calibrate a metallicity indicator for the molecular interstellar medium (abridged).Comment: 14 pages, 9 figures. MNRAS, accepte

Improved chemotaxis differential evolution optimization algorithm

The social foraging behavior of Escherichia coli has recently received great attention and it has been employed to solve complex search optimization problems.This paper presents a modified bacterial foraging optimization BFO algorithm, ICDEOA (Improved Chemotaxis Differential Evolution Optimization Algorithm), to cope with premature convergence of reproduction operator.In ICDEOA, reproduction operator of BFOA is replaced with probabilistic reposition operator to enhance the intensification and the diversification of the search space.ICDEOA was compared with state-of-the-art DE and non-DE variants on 7 numerical functions of the 2014 Congress on Evolutionary Computation (CEC 2014). Simulation results of CEC 2014 benchmark functions reveal that ICDEOA performs better than that of competitors in terms of the quality of the final solution for high dimensional problems

CO Tully–Fisher relation of star-forming galaxies at = 0.05–0.3

The Tully–Fisher relation (TFR) is an empirical relation between galaxy luminosity and rotation velocity. We present here the first TFR of galaxies beyond the local Universe that uses carbon monoxide (CO) as the kinematic tracer. Our final sample includes 25 isolated, non-interacting star-forming galaxies with double-horned or boxy CO integrated line profiles located at redshifts z ≤ 0.3, drawn from a larger ensemble of 67 detected objects. The best reverse Ks-band, stellar mass and baryonic mass CO TFRs are, respectively, MKs = (−8.4 ± 2.9)[log ( W50/km s−1 sin i ) − 2.5] + (−23.5 ± 0.5), log (M/M) = (5.2 ± 3.0)[log ( W50/km s−1 sin i ) − 2.5] + (10.1 ± 0.5) and log (Mb/M) = (4.9 ± 2.8)[log ( W50/km s−1 sin i ) − 2.5] + (10.2 ± 0.5), where MKs is the total absolute Ks-band magnitude of the objects, M and Mb their total stellar and baryonic masses, and W50 the width of their line profile at 50 per cent of the maximum. Dividing the sample into different redshift bins and comparing to the TFRs of a sample of local (z = 0) star-forming galaxies from the literature, we find no significant evolution in the slopes and zero-points of the TFRs since z ≈ 0.3, this in either luminosity or mass. In agreement with a growing number of CO TFR studies of nearby galaxies, we more generally find that CO is a suitable and attractive alternative to neutral hydrogen (HI). Our work thus provides an important benchmark for future higher redshift CO TFR studies

Down but not out: properties of the molecular gas in the stripped Virgo Cluster early-type galaxy NGC4526

We present ALMA data on the 3mm continuum emission, CO isotopologues (12CO, 13CO, C18O), and high-density molecular tracers (HCN, HCO+, HNC, HNCO, CS, CN, and CH3OH) in NGC4526. These data enable a detailed study of the physical properties of the molecular gas in a longtime resident of the Virgo Cluster; comparisons to more commonly-studied spiral galaxies offer intriguing hints into the processing of molecular gas in the cluster environment. Many molecular line ratios in NGC4526, along with our inferred abundances and CO/H2 conversion factors, are similar to those found in nearby spirals. One striking exception is the very low observed 12CO/13CO(1-0) line ratio, $3.4\pm0.3$, which is unusually low for spirals though not for Virgo Cluster early-type galaxies. We carry out radiative transfer modeling of the CO isotopologues with some archival (2-1) data, and we use Bayesian analysis with Markov chain Monte Carlo techniques to infer the physical properties of the CO-emitting gas. We find surprisingly low [12CO/13CO] abundance ratios of $7.8^{+2.7}_{-1.5}$ and $6.5^{+3.0}_{-1.3}$ at radii of 0.4 kpc and 1 kpc. The emission from the high-density tracers HCN, HCO+, HNC, CS and CN is also relatively bright, and CN is unusually optically thick in the inner parts of NGC4526. These features hint that processing in the cluster environment may have removed much of the galaxy's relatively diffuse, optically thinner molecular gas along with its atomic gas. Angular momentum transfer to the surrounding intracluster medium may also have caused contraction of the disk, magnifying radial gradients such as we find in [13CO/C18O]. More detailed chemical evolution modeling would be interesting in order to explore whether the unusual [12CO/13CO] abundance ratio is entirely an environmental effect or whether it also reflects the relatively old stellar population in this early-type galaxy.Comment: Submitted to ApJ. Comments are welcome