פרסומים

Changes in circadian rhythms of behavior are related to age-based division of labor in honey bee colonies. The expression of the clock gene period (per) in the bee brain is associated with age-related changes in circadian rhythms of behavior, but previous efforts to firmly associate per brain expression with division of labor or age have produced variable results. We explored whether this variability was due to differences in light and flight experience, which vary with division of labor, or differences in colony environment, which are known to affect honey bee behavioral development. Our results support the hypothesis that per mRNA expression in the bee brain is developmentally regulated. One-day-old bees had the lowest levels of expression and rarely showed evidence of diurnal fluctuation, while foragers and forager-age bees (>21 days of age) always had high levels of brain per and strong and consistent diurnal patterns. Results from laboratory and field experiments do not support the hypothesis that light, flight experience, and colony type influence per expression. Our results suggest that the rate of developmental elevation in per expression is influenced by factors other than the ones studied in our experiments, and that young bees are more sensitive to these factors than foragers. (C) 2004 Elsevier Ltd. All rights reserved.

Fine boron powd. particles with diam. of ≤1 $μ$m were encapsulated in poly(Me methacrylate-Et acrylate) using water/oil/water (W/O/W) double emulsion. The microencapsulation process, factors affecting microcapsule (MIC) formation and dimensions, and flocculation phenomena of the encapsulated powders, were studied to optimize the product. Optical and SEM observations indicate that the double emulsion technique yielded microcapsules with diam. of 30 to 250 $μ$m, depending on the process parameters. Two encapsulation mechanisms are proposed. The first, prevailing at low vol. fraction of the primary emulsion (ϕ2 ≤ 0.01), leads to the formation of MICs derived from discrete secondary emulsion droplets. The second, which is more significant with the increase of ϕ2, at boron-to-polymer ratio (n) of 0.7, is derived from the coalescence of the secondary emulsion drops, leading to sepn. of polymer-boron aggregates. The most problematic step of microencapsulation is the drying process of MICs. At n = 0.7, hypo-osmotic drying leads to partial water withdrawal from the drop interior upon heating and solvent evapn.; the boron particles do not form a solid core. Water diln. of the double emulsion results in addnl. osmotic water withdrawal from the MIC interior. MICs from discrete liq. drops or from sepd. aggregates have similar (30-50 $μ$m) dimensions detd. by the d. matching law. Microgranulated powders prepd. at n = 0.7, may result in flocs due to the agglomeration of polymer-boron aggregates during the drying process. The dimensions of the flocs depend on the drying regime that can be controlled to form particles of desired dimensions. At n = 1 and ϕ2 = 0.01, when water is completely eliminated from MICs simultaneously with solvent evapn., fast drop solidification leads to the formation of solid core. The diam. of the resulting MICs is 200-250 $μ$m. Powd. boron is a component of propellants, and encapsulation provides for coarsening of particles and surface protection, both of which are required for the application. [on SciFinder(R)]

1-Alkynylboronates form five-membered zirconacycles with Cp(2)ZrCl(2)/2-EtMgBr as indicated by deuterium labeling. The zirconacycles add aldehydes to form seven-membered zirconacycles. Hydrolysis of the latter provides 5-hydroxy-1-alkenylboronates in fair to good isolated yields. Both aliphatic and aromatic aldehydes undergo insertion.

Contrary to the conventional assumption that individuals maximize payoffs, robust experimental studies show that individuals who face repeated choices involving probabilistic costs and benefits often make sub-optimal decisions by applying the strategy of "probability matching." The following study, by integrating this literature with the traditional models of law and economics, and through experimental illustration, presents the possible effects of probability matching in the legal context. The paper also explores how probability matching can guide policy making.

The article focuses on exposure of 54 members of the Israeli Knesset, competing for media coverage. Tangibly, political power provides legislators with the ability to create newsworthy events, access to important and interesting information, and easy access to reporters, who routinely cover the offices the powerful legislators hold. Other variables that have been linked to leaders' publicity can be categorized under the heading of "media skills." The studies demonstrate that media coverage of legislators is influenced by more "macro" variables, such as the political and media cultures in which the competition over publicity is taking place and changes in the political environment.