445 research outputs found
Conditions of the Development of Logistic Centers in Poland in the Context of European States Experiences
The article is, for the most part, the aftermath of his own examinations carried out in years 2007-2010 and concerning logistic centers development conditioning.ArtykuĆ jest w znacznej mierze pokĆosiem badaĆ wĆasnych autora przeprowadzonych w latach: 2007-2010 dotyczÄ
cych uwarunkowaĆ rozwoju centrĂłw logistycznych
Neighbouring residue effects on the ^(15)N chemical shifts of some aliphatic dipeptides
The ^(15)N chemical shifts of a number of simple aliphatic dipeptides have been determined in a aqueous solution and while the amine nitrogen shift is independent of the nature of the neighbouring residue, the peptide nitrogen shift shows a marked dependence upon the nature of the adjacent amino-acid
Altered operant responding for motor reinforcement and the determination of benchmark doses following perinatal exposure to low-level 2,3,7,8-tetrachlorodibenzo-p-dioxin.
Pregnant Holtzman rats were exposed to a single oral dose of 0, 20, 60, or 180 ng/kg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the 18th day of gestation. Their adult female offspring were trained to respond on a lever for brief opportunities to run in specially designed running wheels. Once they had begun responding on a fixed-ratio 1 (FR1) schedule of reinforcement, the fixed-ratio requirement for lever pressing was increased at five-session intervals to values of FR2, FR5, FR10, FR20, and FR30. We examined vaginal cytology after each behavior session to track estrous cyclicity. Under each of the FR values, perinatal TCDD exposure produced a significant dose-related reduction in the number of earned opportunities to run, the lever response rate, and the total number of revolutions in the wheel. Estrous cyclicity was not affected. Because of the consistent dose-response relationship at all FR values, we used the behavioral data to calculate benchmark doses based on displacements from modeled zero-dose performance of 1% (ED(01)) and 10% (ED(10)), as determined by a quadratic fit to the dose-response function. The mean ED(10) benchmark dose for earned run opportunities was 10.13 ng/kg with a 95% lower bound of 5.77 ng/kg. The corresponding ED(01) was 0.98 ng/kg with a 95% lower bound of 0.83 ng/kg. The mean ED(10) for total wheel revolutions was calculated as 7.32 ng/kg with a 95% lower bound of 5.41 ng/kg. The corresponding ED(01) was 0.71 ng/kg with a 95% lower bound of 0.60. These values should be viewed from the perspective of current human body burdens, whose average value, based on TCDD toxic equivalents, has been calculated as 13 ng/kg
Rapid continuous microwave-assisted synthesis of silver nanoparticles to achieve very high productivity and full yield : from mechanistic study to optimal fabrication strategy
Systematic studies of silver nanoparticle synthesis in a continuous-flow single-mode microwave reactor using polyol process were performed, revealing that the synthesis is exceptionally effective to give very small metal particles at full reaction yield and very high productivity. Inlet concentration of silver nitrate or silver acetate, applied as metal precursors, varied between 10 and 50 mM, and flow rates ranged from 0.635 to 2.5 dm3/h, to give 3â24 s reaction time. Owing to its much higher reactivity, silver acetate was shown to be far superior substrate for the synthesis of small (10â20 nm) spherical silver nanoparticles within a few seconds. Its restricted solubility in ethylene glycol, applied as the solvent and reducing agent, appeared to be vital for effective separation of the stage of particle growth from its nucleation to enable rapid synthesis of small particles in a highly loaded system. This was not possible to obtain using silver nitrate. All the observations could perfectly be explained by a classical LaMerâDinegar model of NPsâ formation, but taking into account also nonisothermal character of the continuous-flow process and acetate dissolution in the reaction system. The performed studies indicate an optimal strategy for the high-yield fabrication of metal particles using polyol method
Archives of thrill: the V-Armchair experience
Technology for older people is typically concerned either with health care or accessibility of existing systems. In this paper we take a more âentertainment-orientedâ approach to developing experiences aimed at older users. We describe here the design, development and a user study of the V-Armchair, a virtual reality and motion platform based roller coaster experience. The V-Armchair constitutes a blueprint for the digital archiving of physical ride experiences through the simultaneous capture of 360 video, sound and motion. It gives access to thrill experiences to those who may not be able to go on real thrill rides, such as older riders, and it can be considered as a class of technology that could help to support âactive agingâ as defined by the World Health Organisation. We discuss strategies for capturing and then âtoning downâ motion experiences to make them accessible for older users. We present a study which explores the user experience of the V-Armchair with an older group (median age 63) using a DK2 headset, and a younger group (median age 25) using a CV1 headset, via thematic analysis of semi-structured interviews and a modified version of the Game Experience Questionnaire, and discuss emergent themes such as the role of the presenter, reminiscence, presence and immersion
Dynamics of an Idealized Fluid Model for Investigating Convective-scale Data Assimilation
An idealized fluid model of convective-scale numerical weather prediction, intended for use in inexpensive data assimilation experiments, is described here and its distinctive dynamics are investigated. The model modifies the rotating shallow water equations to include some simplified dynamics of cumulus convection and associated precipitation, extending and improving the model of WĂŒrsch and Craig. Changes to this original model are the removal of ad hoc diffusive terms and the addition of Coriolis rotation terms, leading to a so-called 1.5-dimensional model. Despite the non-trivial modifications to the parent equations, it is shown that this shallow water type model remains hyperbolic in character and can be integrated accordingly using a discontinuous Galerkin finite element method for nonconservative hyperbolic systems of partial differential equations. Combined with methods to ensure well-balancedness and non-negativity, the resulting numerical solver is novel, efficient and robust. Classical numerical experiments in the shallow water theory, such as the Rossby geostrophic adjustment and flow over topography, are reproduced for the standard shallow water model and used to highlight the modified dynamics of the new model. In particular, it exhibits important aspects of convective-scale dynamics relating to the disruption of large-scale balance and is able to simulate other features related to convecting and precipitating weather systems. Our analysis here and preliminary results suggest that the model is well suited for efficiently and robustly investigating data assimilation schemes in an idealized âconvective-scaleâ forecast assimilation framework
Coldâpoolâdriven convective initiation: using causal graph analysis to determine what convectionâpermitting models are missing
Coldâpoolâdriven convective initiation is investigated in highâresolution, convectionâpermitting simulations with a focus on the diurnal cycle and organization of convection and the sensitivity to grid size. Simulations of four different days over Germany were performed using the ICONâLEM model with grid sizes from 156 to 625âm. In these simulations, we identify cold pools, coldâpool boundaries and initiated convection. Convection is triggered much more efficiently in the vicinity of cold pools than in other regions and can provide as much as 50% of total convective initiation, in particular in the late afternoon. By comparing different model resolutions, we find that cold pools are more frequent, smaller and less intense in lowerâresolution simulations. Furthermore, their gust fronts are weaker and less likely to trigger new convection. To identify how model resolution affects this triggering probability, we use a linear causal graph analysis. In doing so, we postulate a graph structure with potential causal pathways and then apply multiâlinear regression accordingly. We find a dominant, systematic effect: reducing grid sizes directly reduces upward mass flux at the gust front, which causes weaker triggering probabilities. These findings are expected to be even more relevant for kmâscale, numerical weather prediction models. We thus expect that a better representation of coldâpoolâdriven convective initiation will improve forecasts of convective precipitation
Assessing New England Family Forest Owners\u27 Invasive Insect Awareness
Family forest owners in the United States have underscored the need for forest insect pest (FIP) information, and numerous Extension programs have been developed to meet pest information needs. We developed the Pest Awareness Index to illustrate the heterogeneity of familiarity, knowledge, and experience regarding three FIPs (hemlock woolly adelgid, emerald ash borer, Asian long-horned beetle) in four New England states. Using mail survey data of family forest owners, we calculated an index from three components and provided comparisons based on region and actual insect presence. The differences in the index across these domains have implications for measurement and delivery of Extension programs
Experimental investigation of mid-infrared laser action from DY3+ doped fluorozirconate fiber
Efficient continuous-wave laser operation at 2.982 ÎŒm is achieved with a Dy3:fluoride fiber pumped using an inhouse-built 1.1 ÎŒm ytterbium (III) fiber laser. The laser output power reached is 554 mW, with a maximum slope efficiency of 18% with respect to the launched pump power. Additionally, the measured spontaneous luminescence within the visible wavelength range, under 1.1 ÎŒm pumping, is presented and attributed to excited state absorption (ESA). The influence of the ESA on the laser performance is discussed. The results confirm that high output powers from Dy: fluoride fiber laser pumped at 1.1 ÎŒm are possible
- âŠ