Influence of environmental experience on aversive conditioning in honey bees (Apis mellifera L.)

International audiencePrevious experience in a natural environment with a stimulus has lasting influences on honey bee behavior, as demonstrated in laboratory studies of appetitive conditioning. However, it is unknown whether the same holds true for studies of aversive conditioning. Aversive conditioning is important for insects such as honey bees to survive environmental risks. Previous experience in natural settings may lead to maladaptive behavioral patterns in bees exposed to new risks. This study presents the first examination of the effect of a visual stimulus presented in a naturalistic setting on aversive conditioning, using the shuttle box choice chamber paradigm. The present study examines both the effect of the visual stimuli, as well as differences present between the Apis mellifera subspecies of mellifera and ligustica. Results support the presence of behavioral biases based on the visual stimulus presented prior to the experimental sessions

Transport properties of dense fluid argon

We calculate using molecular dynamics simulations the transport properties of realistically modeled fluid argon at pressures up to $\simeq 50GPa$ and temperatures up to $3000K$. In this context we provide a critique of some newer theoretical predictions for the diffusion coefficients of liquids and a discussion of the Enskog theory relevance under two different adaptations: modified Enskog theory (MET) and effective diameter Enskog theory. We also analyze a number of experimental data for the thermal conductivity of monoatomic and small diatomic dense fluids.Comment: 8 pages, 6 figure

Satellite content and quenching of star formation in galaxy groups at z ~ 1.8

We study the properties of satellites in the environment of massive star-forming galaxies at z ~ 1.8 in the COSMOS field, using a sample of 215 galaxies on the main sequence of star formation with an average mass of ~1011M⊙. At z> 1.5, these galaxies typically trace halos of mass ≳1013M⊙. We use optical-near-infrared photometry to estimate stellar masses and star formation rates (SFR) of centrals and satellites down to ~ 6 × 109M⊙. We stack data around 215 central galaxies to statistically detect their satellite halos, finding an average of ~3 galaxies in excess of the background density. We fit the radial profiles of satellites with simple β-models, and compare their integrated properties to model predictions. We find that the total stellar mass of satellites amounts to ~68% of the central galaxy, while spectral energy distribution modeling and far-infrared photometry consistently show their total SFR to be 25-35% of the central's rate. We also see significant variation in the specific SFR of satellites within the halo with, in particular, a sharp decrease at <100 kpc. After considering different potential explanations, we conclude that this is likely an environmental signature of the hot inner halo. This effect can be explained in the first order by a simple free-fall scenario, suggesting that these low-mass environments can shut down star formation in satellites on relatively short timescales of ~0.3 Gyr

Thin bed masonry system: review and future prospects

Masonry is one of the most ancient construction materials in the World. When compared to other civil engineering practices, masonry construction is highly labour intensive, which can affect the quality and productivity adversely. With a view to improving quality and in light of the limited skilled labour in the recent times several innovative masonry construction methods such as the dry stack and the thin bed masonry have been developed. This paper focuses on the thin bed masonry system, which is used in many parts of Europe. Thin bed masonry system utilises thin layer of polymer modified mortars connecting the accurately dimensioned and/or interlockable units. This assembly process has the potential for automated panelised construction system in the industry setting or being adopted in the site using less skilled labour, without sacrificing the quality. This is because unlike the conventional masonry construction, the thin bed technology uses thinner mortar (or glue) layer which can be controlled easily through some novel methods described in this paper. Structurally, reduction in the thickness of the mortar joint has beneficial effects; for example it increases the compressive strength of masonry; in addition polymer added glue mortar enhances lateral load capacity relative to conventional masonry. This paper reviews the details of the recent research outcomes on the structural characteristics and construction practices of thin bed masonry. Finally the suitability of thin bed masonry in developing countries where masonry remains as the most common material for residential building construction is discussed

Retinoblastoma

Retinoblastoma is a rare eye tumor of childhood that arises in the retina. It is the most common intraocular malignancy of infancy and childhood; with an incidence of 1/15,000–20,000 live births. The two most frequent symptoms revealing retinoblastoma are leukocoria and strabismus. Iris rubeosis, hypopyon, hyphema, buphthalmia, orbital cellulites and exophthalmia may also be observed. Sixty per cent of retinoblastomas are unilateral and most of these forms are not hereditary (median age at diagnosis two years). Retinoblastoma is bilateral in 40% of cases (median age at diagnosis one year). All bilateral and multifocal unilateral forms are hereditary. Hereditary retinoblastoma constitutes a cancer predisposition syndrome: a subject constitutionally carrying an RB1 gene mutation has a greater than 90% risk of developing retinoblastoma but is also at increased risk of developing other types of cancers. Diagnosis is made by fundoscopy. Ultrasound, magnetic resonance imaging (MRI) and computed tomography (CT) scans may contribute to diagnosis. Management of patients with retinoblastoma must take into account the various aspects of the disease: the visual risk, the possibly hereditary nature of the disease, the life-threatening risk. Enucleation is still often necessary in unilateral disease; the decision for adjuvant treatment is taken according to the histological risk factors. Conservative treatment for at least one eye is possible in most of the bilateral cases. It includes laser alone or combined with chemotherapy, cryotherapy and brachytherapy. The indication for external beam radiotherapy should be restricted to large ocular tumors and diffuse vitreous seeding because of the risk of late effects, including secondary sarcoma. Vital prognosis, related to retinoblastoma alone, is now excellent in patients with unilateral or bilateral forms of retinoblastoma. Long term follow-up and early counseling regarding the risk of second primary tumors and transmission should be offered to retinoblastoma patients

Optimal interdependence between networks for the evolution of cooperation

Recent research has identified interactions between networks as crucial for the outcome of evolutionary games taking place on them. While the consensus is that interdependence does promote cooperation by means of organizational complexity and enhanced reciprocity that is out of reach on isolated networks, we here address the question just how much interdependence there should be. Intuitively, one might assume the more the better. However, we show that in fact only an intermediate density of sufficiently strong interactions between networks warrants an optimal resolution of social dilemmas. This is due to an intricate interplay between the heterogeneity that causes an asymmetric strategy flow because of the additional links between the networks, and the independent formation of cooperative patterns on each individual network. Presented results are robust to variations of the strategy updating rule, the topology of interdependent networks, and the governing social dilemma, thus suggesting a high degree of universality

A framework for processing wave buoy measurements in the presence of current

This is the final version. Available on open access from Elsevier via the DOI in this record.Waves and currents interact, with the resulting combination largely determining the loading on offshore structures and devices. Despite this, currents are often ignored and wave buoy data is processed without consideration of the current or the wave-current interaction. This data is subsequently used in design, yet sea state power, steepness, and directionality may have significant errors. Here we present a novel framework for the processing of wave buoy data to account for the effect of a current. We use a mesh adaptive direct search (MADS) algorithm to solve for the current and current-modified wave parameters simultaneously. Through 125 simulated directional wave-current sea states, we demonstrate the performance of the method under a wide range of conditions; including bimodal sea states with non-colinear current. Current speed and direction are estimated accurately for all cases (mean RMSE of 0.1179 m s−1 and 0.0091 rad respectively) which enables sea state steepness and power to be estimated within ±3%. Ignoring this current of ±2 m s−1 when deriving these wave parameters results in errors up to 30%. This work demonstrates that it is possible to correctly process wave buoy measurement data to account for, and quantify, a current thus significantly reducing the uncertainty of the ocean conditions. After further validation work, the framework can be widely applied to historic datasets, correcting the wave data and providing an additional dataset of current velocities.Engineering and Physical Sciences Research Council (EPSRC)Dame Kathleen Ollerenshaw Fellowshi

A comprehensive list of asthmagens to inform health interventions in the Australian workplace

Objective: To develop a comprehensive list of asthmagens which may occur in occupational settings in Australia. Methods: Potential asthmagens considered for this list were identified through work health and safety classification databases in Australia and through lists developed by professional associations in other countries. Inclusion criteria were: there is evidence that the agent is asthmagenic; it is used in occupational settings; and it is available in Australia. Results: The final list contained 277 asthmagens in 27 groups that may be found in occupational circumstances in Australia. Three other agents that have been documented as asthmagens in Australia were included: almond dust, fluoride (in aluminium pot room fumes); and sawdust from the Australian Blackwood. Conclusions: This is the first comprehensive and inclusive list of Australian occupationally relevant asthmagens to have been compiled. Implications: This list is specific for Australian workplace exposure to asthmagens. It will help focus policy and preventative practices and reduce the burden of occupational asthma. It will also be useful in future studies to identify those who are exposed to the asthmagens and provide information to assist regulators to identify industries, occupations, specific activities and existing exposure standards that can be targeted to improve worker health and welfare