Sex- and season-dependent behaviour in a flightless insect, the Auckland tree weta (Hemideina thoracica)

In a polygynous mating system, males frequently compete by locating and defending sites with resources essential to female survival and reproduction. We investigated seasonal changes in site occupancy in a sexually dimorphic, harem-forming insect, the Auckland tree weta (Hemideina thoracica). First we established artificial cavities as diurnal refuge cavities and potential harem guarding sites. We then examined cavity occupancy changes, and, based on our knowledge of prior occupants, determined sex-specific patterns of arrival, departure, and aggregation at a population level throughout the year. Both season and the sex of prior occupants influenced weta occupancy patterns. Most observations were of single females. However, both males and females moved into cavities previously occupied by a weta of the opposite sex more often than expected by chance alone. Females avoided cavities where other females were present, except during summer when most harems formed. In early summer, male and female tree weta previously living apart began co-habiting. Generally there was little relationship between the number and sex of the weta inside cavities and female departure rates from cavities. Males who were sharing with other males departed cavities more frequently than single males, as might be expected in a polygynous species with male-male combat. Males were less likely to depart if they were sharing a cavity with a harem of more than two females during the summer-autumn period. Analysis of departure rates from artificial cavities indicates males are more mobile than females only in winter and spring. Based on our arrival and departure data, and high occupancy of artificial cavities, we suggest that female weta at this site are mobile and may search for mates during the summer. The data are consistent with a polygynandrous mating system as inferred for other tree weta species (Hemideina spp.)

Complementary Currencies for Sustainable Development in Kenya

This paper is a report on the development of a complementary currency system that allows Kenyans in informal settlements to trade goods and services and meet sustainable development objectives. The system in this report, Bangla-Pesa, uses a ‘collaborative credit’ model through a network of local business, whose owners often struggle to meet their basic needs (also known as ‘mutual credit’). The paper documents the reasons for its creation, how it was launched, the immediate positive benefits upon launch, and some of the difficulties faced. Bangla-Pesa is shown to have facilitated, upon its launch, exchanges of roughly 50 Euros in value per day among 109 businesses, which is projected to raise living standards in the community primarily through the utilization of excess business capacity. After only a week of circulation – Bangla-Pesa represented an estimated 22 total trade among community members. This system’s implementation and governance model are detailed with the aim of improving upon and replicating the model for future sustainable development programs

A GPU-Enabled, High-Resolution Cosmological Microlensing Parameter Survey

In the era of synoptic surveys, the number of known gravitationally lensed quasars is set to increase by over an order of magnitude. These new discoveries will enable a move from single-quasar studies to investigations of statistical samples, presenting new opportunities to test theoretical models for the structure of quasar accretion discs and broad emission line regions (BELRs). As one crucial step in preparing for this influx of new lensed systems, a large-scale exploration of microlensing convergence-shear parameter space is warranted, requiring the computation of O(10^5) high resolution magnification maps. Based on properties of known lensed quasars, and expectations from accretion disc/BELR modelling, we identify regions of convergence-shear parameter space, map sizes, smooth matter fractions, and pixel resolutions that should be covered. We describe how the computationally time-consuming task of producing ~290000 magnification maps with sufficient resolution (10000^2 pixel/map) to probe scales from the inner edge of the accretion disc to the BELR can be achieved in ~400 days on a 100 teraflop/s high performance computing facility, where the processing performance is achieved with graphics processing units. We illustrate a use-case for the parameter survey by investigating the effects of varying the lens macro-model on accretion disc constraints in the lensed quasar Q2237+0305. We find that although all constraints are consistent within their current error bars, models with more densely packed microlenses tend to predict shallower accretion disc radial temperature profiles. With a large parameter survey such as the one described here, such systematics on microlensing measurements could be fully explored.Comment: 30 pages, 3 figures, accepted for publication in Ap

Comparing Narratives of Personal and Preferred Partner Characteristics in Online Dating Advertisements

This study explored online personal ads of 294 heterosexual and homosexual men and women in the United States through a qualitative analysis and comparison of participant-generated “personal” and “preferred partner” narratives. Nine characteristics were identified and combined into three overarching categories: physical, lifestyle, and personality characteristics. These three personal and preferred partner characteristics were examined for difference by gender, sexual orientation, age and desired relationship type of the advertisers. Main effects emerged for all four predictors, most notably for age and desired relationship type. Additionally, this study explored the possibility that personal and preferred partner narratives contained similar constellations of characteristics, finding significant correlations on all three variables, lending support for the matching hypothesis in dating partner characteristics

The Quasar Accretion Disk Size - Black Hole Mass Relation

We use the microlensing variability observed for nine gravitationally lensed quasars to show that the accretion disk size at 2500 Angstroms is related to the black hole mass by log(R_2500/cm) = (15.6+-0.2) + (0.54+-0.28)log(M_BH/10^9M_sun). This scaling is consistent with the expectation from thin disk theory (R ~ M_BH^(2/3)), but it implies that black holes radiate with relatively low efficiency, log(eta) = -1.29+-0.44 + log(L/L_E) where eta=L/(Mdot c^2). These sizes are also larger, by a factor of ~3, than the size needed to produce the observed 0.8 micron quasar flux by thermal radiation from a thin disk with the same T ~ R^(-3/4) temperature profile. More sophisticated disk models are clearly required, particularly as our continuing observations improve the precision of the measurements and yield estimates of the scaling with wavelength and accretion rate.Comment: 5 pages, 3 figures, submitted to ApJ

Sizes and Temperature Profiles of Quasar Accretion Disks from Chromatic Microlensing

Microlensing perturbations to the flux ratios of gravitationally lensed quasar images can vary with wavelength because of the chromatic dependence of the accretion disk's apparent size. Multiwavelength observations of microlensed quasars can thus constrain the temperature profiles of their accretion disks, a fundamental test of an important astrophysical process which is not currently possible using any other method. We present single-epoch broadband flux ratios for 12 quadruply lensed quasars in eight bands ranging from 0.36 to 2.2 microns, as well as Chandra 0.5--8 keV flux ratios for five of them. We combine the optical/IR and X-ray ratios, together with X-ray ratios from the literature, using a Bayesian approach to constrain the half-light radii of the quasars in each filter. Comparing the overall disk sizes and wavelength slopes to those predicted by the standard thin accretion disk model, we find that on average the disks are larger than predicted by nearly an order of magnitude, with sizes that grow with wavelength with an average slope of ~0.2 rather than the slope of 4/3 predicted by the standard thin disk theory. Though the error bars on the slope are large for individual quasars, the large sample size lends weight to the overall result. Our results present severe difficulties for a standard thin accretion disk as the main source of UV/optical radiation from quasars.Comment: 21 pages, 9 tables, 10 figures. Fairly significant changes made to match published version, including the addition of an extra table, and extra figure, and some explanatory tex

Resource Recovery from Waste: Restoring the Balance between Resource Scarcity and Waste Overload

Current societal patterns of production and consumption drive a twin environmental crisis of resource scarcity and waste overload. Positioning waste and resource management in the context of ecosystem stewardship, this article relates increasing resource demand and waste production to the violation of planetary boundaries and human rights. We argue that a transition towards a circular economy (CE) that contributes to a resilient environment and human well-being is necessary to achieve the UN Sustainable Development Goals. The transition requires scientific and technological progress, including the development of low-energy biogeochemical technologies for resource recovery, and multi-dimensional value assessment tools integrating environmental, social, and economic factors. While the urgency to adopt a CE is well-recognised, progress has been slow. Coordinated change is required from multiple actors across society. Academia can contribute through participatory action research. This article concludes with the participation strategy of the Resource Recovery from Waste programme, aiming for changes in mentality, industry practices, and policies and regulations in the waste and resource management landscape in the UK