Winged queens replaced by reproductives smaller than workers in <Emphasis Type="Italic">Mystrium</Emphasis> ants

In ants, winged queens that are specialized for independent colony foundation can be replaced by wingless reproductives better adapted for colony fission. We studied this shift in reproductive strategy by comparing two Mystrium species from Madagascar using morphometry, allometry and dissections. Mystrium rogeri has a single dealate queen in each colony with a larger thorax than workers and similar mandibles that allow these queens to hunt during non-claustral foundation. In contrast, Mystrium ‘red’ lacks winged queens and half of the female adults belong to a wingless ‘intermorph’ caste smaller and allometrically distinct from the workers. Intermorphs have functional ovaries and spermatheca while those of workers are degenerate. Intermorphs care for brood and a few mate and reproduce making them an all-purpose caste that takes charge of both work and reproduction. However, their mandibles are reduced and inappropriate for hunting centipedes, unlike the workers’ mandibles. This together with their small thorax disallow them to perform independent colony foundation, and colonies reproduce by fission. M. rogeri workers have mandibles polymorphic in size and shape, which allow for all tasks from brood care to hunting. In M. ‘red’, colonial investment in reproduction has shifted from producing expensive winged queens to more numerous helpers. M. ‘red’ intermorphs are the first case of reproductives smaller than workers in ants and illustrate their potential to diversify their caste system for better colonial economy.     

Cooling rate limitations in the diffusion bonding of microchannel arrays

A significant barrier to the diffusion bonding of microchannel arrays is the large capital investment required to setup production. This large capital investment extends from long heating and cooling cycles leading to poor production capacities. Empirical studies in industry have shown that cooling rate is limited by the warpage of microchannel laminae, which is believed to be caused by thermal buckling. In this paper, the limits of cooling rates based on thermal buckling during the diffusion bonding of microchannel laminae are investigated. Finite element analyses of the transient thermal and stress behaviors of these microchannel laminae were conducted to identify the maximum cooling rates for different lamina thicknesses. Findings confirm that cooling rates are limited by the thermal buckling of unconstrained microchannel laminae during cooling of the device. Finite element analysis results are used to extrapolate implications for microchannel production.     

Correction: Nonparametric conditional density estimation in a deep learning framework for short-term forecasting

Environmental and Ecological Statistics -     

Nonparametric conditional density estimation in a deep learning framework for short-term forecasting

Environmental and Ecological Statistics - Short-term forecasting is an important tool in understanding environmental processes. In this paper, we incorporate machine learning algorithms into a...     

Renewable and non-renewable energy consumption driven sustainable development in ASEAN countries: do financial development and institutional quality matter?

Environmental Science and Pollution Research - Energy consumption for sustainable development has become a crucial issue in recent years. The anthropogenic effects of traditional energy sources...     

Residues of organochlorine compounds in starlings (Sturnus vulgaris), 1979

Starlings were collected for the National Pesticides Monitoring Program from 112 sites throughout the contiguous United States and analyzed for organochlorine compounds. Starling samples from 14 sites had greater than 1.0 ppm DDE residues with the highest DDE level being 15.8 ppm in a sample taken near Roswell, New Mexico. The occurrence of PCBs and chlordane isomers increased since the 1976 collection, but DDT, DDE, and dieldrin occurrence decreased. DDE and dieldrin levels decreased since the 1976 collection, but the level of PCBs has increased.     

Analysis of precipitation-related motor vehicle collision and injury risk using insurance and police record information for Winnipeg, Canada

Introduction

Police records are the most common source of data used to estimate motor-vehicle collision risks, understand causal or contributing factors, and evaluate the efficacy of interventions. The literature notes concerns about this information citing discrepancies between police reports and other sources of injury occurrence and severity data. The primary objective of the analysis was to assess the adequacy of police reports for an examination of weather-related injury collision risk.

Method

Analyses of relative risk were carried out using both police records and comprehensive insurance claim data for Winnipeg, Canada over the period 1999-2001.

Results and conclusions

Both data sets yielded very similar results—precipitation substantially increases the risk of injury collision (police records: RR 1.76, CI 1.55-2.00; insurance: RR 1.80, CI 1.62-1.99) and risk of injury (police records, RR 1.74, CI 1.55-1.96; insurance, RR 1.69, CI 1.55-1.85) relative to corresponding dry weather control periods. Both rainfall and snowfall were associated with large increases in collisions and injuries.

Impact on Industry

While relative risks are almost identical, over 64% more injury collisions and 74% more injuries were identified using the insurance data, which is an important difference for evaluating absolute risk and exposure.     

Environmental fate of pesticides used in Australian viticulture IV. Aqueous stability of dithianon

Dithianon formulations are unstable in slightly basic aqueous solutions (pH 9, 20°C, t _½ = 5.6 h) but relatively stable in neutral or acidic solution (pH 4,20°C, t _½ = 6443 h). To ensure the efficacy of this fungicide it is important to prepare the spray mix fresh with neutral or slightly acidic water. Dithianon is unstable towards natural sunlight in the solid and aqueous phase, with half‐lives of approximately 68 and 42 days, respectively. Thermal hydrolysis does not seem to be the preferred degradation pathway when aqueous solutions are heated by the South Australian summer sun. The major aqueous phase photodegradation product has been identified as 2,3‐dihydro‐1,4‐dithiaanthraquinone. These results strongly suggest that should dithianon be accidentally released into basic Australian waters then it is likely to be rapidly chemically hydrolysed and pose little long term environmental threat. However, dithianon is only slowly chemically and photo‐lytically hydrolysed in neutral and acidic waters, and in this case accidentally release may pose a significant short term environmental threat.     

Assessing historical saltmarsh change; an investigation into the reliability of historical saltmarsh mapping using contemporaneous aerial photography and cartographic data

Habitat protection, creation and management are at the forefront of nature conservation throughout the world. Many terrestrial and marine ecosystems are under pressure from a diverse range of issues including impacts associated with climate change, multiple resource use and increased development. Saltmarsh within the United Kingdom, is one such valuable habitat which has suffered significant losses over the last eighty or so years. Any environmental management practice or decision applied to these areas, should ideally be based on evidence of processes and change. One potential way of measuring saltmarsh change is by using historical maps and aerial photographs to look for patterns of growth or reduction. This research examines the process of saltmarsh mapping and compares historical aerial photographs and maps to assess their suitability for habitat change assessment. This research suggests that whilst historical aerial photography can be accessed and utilised effectively, the data presented on maps should be treated with a great deal of caution. The saltmarsh represented on the maps used in this research was noticeably different from that mapped using aerial photographs from a similar time period. Whilst this does not dismiss the use of historic maps along this part of the coast, it does suggest they should be treated with some degree of caution and will vary in their reliability.     

Comparing modern and presettlement forest dynamics of a subboreal wilderness: does spruce budworm enhance fire risk?

Insect disturbance is often thought to increase fire risk through enhanced fuel loadings, particularly in coniferous forest ecosystems. Yet insect disturbances also affect successional pathways and landscape structure that interact with fire disturbances (and vice-versa) over longer time scales. We applied a landscape succession and disturbance model (LANDIS-II) to evaluate the relative strength of interactions between spruce budworm (Choristoneura fumiferana) outbreaks and fire disturbances in the Boundary Waters Canoe Area (BWCA) in northern Minnesota (USA). Disturbance interactions were evaluated for two different scenarios: presettlement forests and fire regimes vs. contemporary forests and fire regimes. Forest composition under the contemporary scenario trended toward mixtures of deciduous species (primarily Betula papyrifera and Populus spp.) and shade-tolerant conifers (Picea mariana, Abies balsamea, Thuja occidentalis), with disturbances dominated by a combination of budworm defoliation and high-severity fires. The presettlement scenario retained comparatively more "big pines" (i.e., Pinus strobus, P. resinosa) and tamarack (L. laricina), and experienced less budworm disturbance and a comparatively less-severe fire regime. Spruce budworm disturbance decreased area burned and fire severity under both scenarios when averaged across the entire 300-year simulations. Contrary to past research, area burned and fire severity during outbreak decades were each similar to that observed in non-outbreak decades. Our analyses suggest budworm disturbances within forests of the BWCA have a comparatively weak effect on long-term forest composition due to a combination of characteristics. These include strict host specificity, fine-scaled patchiness created by defoliation damage, and advance regeneration of its primary host, balsam fir (A. balsamea) that allows its host to persist despite repeated disturbances. Understanding the nature of the three-way interaction between budworm, fire, and composition has important ramifications for both fire mitigation strategies and ecosystem restoration initiatives. We conclude that budworm disturbance can partially mitigate long-term future fire risk by periodically reducing live ladder fuel within the mixed forest types of the BWCA but will do little to reverse the compositional trends caused in part by reduced fire rotations.