669 research outputs found
Sticky traps saturate with navel orangeworm in a nonlinear fashion
Trapping is an essential tool used to decide the need for and/or timing of an insecticide application. The assumption is that the information is accurate, but accuracy is dependent on trap reliability and efficacy. One factor that affects reliability is trap saturation, defined as the measurable decrease in trap capture due to reduced trapping effectiveness caused by the accumulation of insects already in a trap. In this study, we used unmated female navel orangeworm (NOW, Amyelois transitella (Walker)) as sex pheromone baits in wing traps that varied by color and glue/trapping surface in order to evaluate saturation thresholds and quantify trap effectiveness. Effectiveness decreased in each type of sticky trap as the number of insects caught increased, because of the accumulation of scales and insect bodies on the glue surface. The continued accumulation of insects further reduced trap capture, and this decrease in capture could be described by a regression using a power transformation. The resulting saturation equations that we calculated will help pest control advisers and growers interpret their trap data by better estimating the relationship between the number of males trapped versus those that visited the trap
Identification of novel ER-alpha target genes in breast cancer cells: Gene- and cell-selective co-regulator recruitment at target promoters determines the response to 17beta-estradiol and tamoxifen
International audienceTamoxifen and 17ÎČ-estradiol are capable of up-regulating the expression of some genes and down-regulate the expression of others simultaneously in the same cell. In addition, tamoxifen shows distinct transcriptional activities in different target tissues.To elucidate whether these events are determined by differences in the recruitment of co-regulators by activated estrogen receptor-α (ER-α) at target promoters, we applied chromatin-immunoprecipitation (ChIP) with promoter microarray hybridisation in breast cancer T47D cells and identified 904 ER-α targets genome-wide. On a selection of newly identified targets, we show that 17ÎČ-estradiol and tamoxifen stimulated up- or down-regulation of transcription correlates with the selective recruitment of co-activators or co-repressors, respectively. This is shown for both breast (T47D) and endometrial carcinoma cells (ECC1). Moreover, differential co-regulator recruitment also explains that tamoxifen regulates a number of genes in opposite direction in breast and endometrial cancer cells. Over-expression of co-activator SRC-1 or co-repressor SMRT is sufficient to alter the transcriptional action of tamoxifen on a number of targets. Our findings support the notion that recruitment of co-regulator at target gene promoters and their expression levels determine the effect of ER-α on gene expression to a large extent
Pheromone traps for monitoring Plodia interpunctella (HĂŒbner) (Lepidoptera: Pyralidae) in the presence of mating disruption
High-dose pheromone lures have proved useful for monitoring some lepidopteran pests in the presence of mating disruption, but not others. We performed experiments in commercial and pilot scale facilities to examine the effect of pheromone dose on detection of Indianmeal moth, Plodia interpunctella (Lepidoptera: Pyralidae), in the presence of mating disruption. When P. interpunctella males were released into 1000 m3 rooms containing traps baited with 0, 1, or 10 mg (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:Ac), traps containing 10 mg captured more than those baited with 1 mg in both the presence and absence of mating disruption. Traps baited with 1 mg captured fewer males in the presence of mating disruption than in its absence, but the opposite was observed with traps baited with 10 mg. When males released into 73 m3 rooms were exposed sequentially to blank traps, traps baited with unmated females, and traps baited with 0.1 mg and then 1.0 mg Z9, E12-14:Ac in the presence or absence of mating disruption, 92% of trapped males were captured in female-baited traps in the absence of mating disruption, whereas in the presence of mating disruption 72% of males captured were caught in synthetic pheromone traps. These data suggest that pheromone lures can be used for monitoring P. interpunctella in the presence of mating disruption. Implications of these data for mass trapping are also discussed. Keywords: Plodia interpunctella, Mating disruption, Monitoring, Pheromone lures, Mass trappin
Acoustically-actuated bubble-powered rotational micro-propellers
Bubble-powered acoustic microsystems span a plethora of applications that range from lab-on-chip diagnostic platforms to targeted interventions as microrobots. Numerous studies strategize this bubble-powered mechanism to generate autonomous self-propulsion of microrobots in response to high frequency sound waves. Herein, we present two micro-propeller designs which contain an axis-symmetric distribution of entrapped bubbles that vibrate to induce fast rotational motion. Our micro-propellers are synthesized using 3D Direct Laser Writing and chemically-functionalized to selectively trap air bubbles at their micro-cavities which function as propulsion units. These rotational acoustic micro-propellers offer a dual advantage of being used as mobile microfluidic mixers, and as autonomous microrobots for targeted manipulation. With regards to targeted manipulation, we demonstrate magneto-acoustic actuation of our first propeller design that can be steered to a desired location to perform rotational motion. Furthermore, our second propeller design comprises of a helical arrangement of bubble-filled cavities which makes it suitable for spatial micro-mixing. Our acoustic propellers can reach speeds of up to 400 RPM (rotations per minute) without requiring any direct contact with a vibrating substrate in contrast to the state-of-the-art rotary acoustic microsystems
The shape and erosion of pebbles
The shapes of flat pebbles may be characterized in terms of the statistical
distribution of curvatures measured along their contours. We illustrate this
new method for clay pebbles eroded in a controlled laboratory apparatus, and
also for naturally-occurring rip-up clasts formed and eroded in the Mont
St.-Michel bay. We find that the curvature distribution allows finer
discrimination than traditional measures of aspect ratios. Furthermore, it
connects to the microscopic action of erosion processes that are typically
faster at protruding regions of high curvature. We discuss in detail how the
curvature may be reliable deduced from digital photographs.Comment: 10 pages, 11 figure
Benefits of European climate policies for mercury air pollution
This paper presents the methodology and results of impact assessment of renewable energy policies on atmospheric emissions of mercury in Europe. The modeling exercise described here involves an interaction of several models. First, a set of energy scenarios has been developed with the REMix (Renewable Energy Mix) model that simulates different levels of penetration of renewable energies in the European power sector. The energy scenarios were input to the GAINS (Greenhouse Gas and Air Pollution Interactions and Synergies) model, which prepared projections of mercury releases to the atmosphere through 2050, based on the current air pollution control policies in each country. Data on mercury emissions from individual sectors were subsequently disaggregated to a fine spatial resolution using various proxy parameters. Finally, the dispersion of mercury in the atmosphere was computed by the chemistry transport model, implemented to the air quality system, Polyphemus. The simulations provided information on changes in concentrations and depositions of various forms of mercury over Europe. Scenarios that simulate a substantial expansion of renewable energies within the power sector indicate extensive co-benefits for mercury abatement, due to the restructuring of the energy system and changes in the fuel mix. The potential for mercury reductions in Europe depends on the rate of fuel switches and renewable technology deployment, but is also influenced by the stringency and timing of the air quality measures. The overall scope for co-benefits is therefore higher in regions relying on coal combustion as a major energy source
Bivariate stochastic modeling of functional response with natural mortality
A correction due to Abbott (1925) is the standard method of dealing with control mortality in insect bioassay to estimate the mortality of an insect conditional on control mortality not having occurred. In this article a bivariate stochastic process for overall mortality is developed in which natural mortality and predation are jointly modeled to take account of the competing-risks associated with prey loss. The total mortality estimate from this model is essentially identical with that from more classical modeling. However, when predation loss is estimated in the absence of control mortality the results are somewhat different, with the estimate from the bivariate model being lower than that from using Abbottâs formula in conjunction with the classical model. It is argued that overdispersion in observed mortality data corresponds to correlated outcomes (death or survival) for the prey initially present, while Abbottâs correction relies implicitly on independence
Attractiveness of a Four-component Pheromone Blend to Male Navel Orangeworm Moths
The attractiveness to male navel orangeworm moth, Amyelois transitella, of various combinations of a four-component pheromone blend was measured in wind-tunnel bioassays. Upwind flight along the pheromone plume and landing on the odor source required the simultaneous presence of two components, (11Z,13Z)-hexadecadienal and (3Z,6Z,9Z,12Z,15Z)-tricosapentaene, and the addition of either (11Z,13Z)-hexadecadien-1-ol or (11Z,13E)-hexadecadien-1-ol. A mixture of all four components produced the highest levels of rapid source location and source contact. In wind-tunnel assays, males did not seem to distinguish among a wide range of ratios of any of the three components added to (11Z,13Z)-hexadecadienal. Dosages of 10 and 100Â ng of the 4-component blend produced higher levels of source location than dosages of 1 and 1,000Â ng
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