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Large Shifts (large + shift)
Selected AbstractsBlood,brain barrier damage and brain penetration of antiepileptic drugs: Role of serum proteins and brain edemaEPILEPSIA, Issue 4 2009Nicola Marchi Summary Purpose:, Increased blood,brain barrier (BBB) permeability is radiologically detectable in regions affected by drug-resistant epileptogenic lesions. Brain penetration of antiepileptic drugs (AEDs) may be affected by BBB damage. We studied the effects of BBB damage on brain distribution of hydrophilic [deoxy-glucose (DOG) and sucrose] and lipophilic (phenytoin and diazepam) molecules. We tested the hypothesis that lipophilic and hydrophilic drug distribution is differentially affected by BBB damage. Methods:, In vivo BBB disruption (BBBD) was performed in rats by intracarotid injection of hyperosmotic mannitol. Drugs (H3-sucrose, 3H-deoxy-glucose, 14C-phenytoin, and C14-diazepam) or unlabeled phenytoin was measured and correlated to brain water content and protein extravasation. In vitro hippocampal slices were exposed to different osmolarities; drug penetration and water content were assessed by analytic and densitometric methods, respectively. Results:, BBBD resulted in extravasation of serum protein and radiolabeled drugs, but was associated with no significant change in brain water. Large shifts in water content in brain slices in vitro caused a small effect on drug penetration. In both cases, total drug permeability increase was greater for lipophilic than hydrophilic compounds. BBBD reduced the amount of free phenytoin in the brain. Discussion:, After BBBD, drug binding to protein is the main controller of total brain drug accumulation. Osmotic BBBD increased serum protein extravasation and reduced free phenytoin brain levels. These results underlie the importance of brain environment and BBB integrity in determining drug distribution to the brain. If confirmed in drug-resistant models, these mechanisms could contribute to drug brain distribution in refractory epilepsies. [source] Welfare Reform and the Labour Supply of Lone Parents in Australia: A Natural Experiment ApproachTHE ECONOMIC RECORD, Issue 249 2004Denise J. Doiron Large shifts in the labour supply of lone parents in Australia were observed between 1986 and 1990. Changes in the observed characteristics of lone parents explain only a small portion of these shifts. Propensity score matching and difference-in-differences are used to estimate the effects of the substantial policy shifts implemented in 1987. Control groups are constructed from the sample of married mothers. Results suggest that the policy reforms caused a substantial increase in the employment of lone parents while causing a reduction in the hours of work among the workers. [source] High Quality Factor Metallodielectric Hybrid Plasmonic,Photonic CrystalsADVANCED FUNCTIONAL MATERIALS, Issue 12 2010Xindi Yu Abstract A 2D polystyrene colloidal crystal self-assembled on a flat gold surface supports multiple photonic and plasmonic propagating resonance modes. For both classes of modes, the quality factors can exceed 100, higher than the quality factor of surface plasmons (SP) at a polymer,gold interface. The spatial energy distribution of those resonance modes are carefully studied by measuring the optical response of the hybrid plasmonic,photonic crystal after coating with dielectric materials under different coating profiles. Computer simulations with results closely matching those of experiments provide a clear picture of the field distribution of each resonance mode. For the SP modes, there is strong confinement of electromagnetic energy near the metal surface, while for optical modes, the field is confined inside the spherical particles, far away from the metal. Coating of dielectric material on the crystal results in a large shift in optical features. A surface sensor based on the hybrid plasmonic,photonic crystal is proposed, and it is shown to have atomic layer sensitivity. An example of ethanol vapor sensing based on physisorption of ethanol onto the sensor surface is demonstrated. [source] Ground-State Interaction and Electrical Doping of Fluorinated C60 in Conjugated PolymersADVANCED MATERIALS, Issue 44 2009Olga Solomeshch C60F36 is reported to be an efficient dopant for conjugated polymers. Its fluorine atoms induce a large shift in the energy levels with respect to C60. Its role as a dopant is studied by examining the charge transfer formed with the commonly used polymer, P3HT. [source] North American weather-type frequency and teleconnection indicesINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 1 2003Scott C. Sheridan Abstract The impact of teleconnections upon the surface climate has largely been examined via a response in monthly mean temperature or total precipitation. In this paper, a different approach is undertaken, by examining the response of synoptic weather-type frequencies to different teleconnection phases. For over 330 stations in the USA and Canada, the Spatial Synoptic Classification scheme has classified each day in each station's period of record into one of seven weather-type categories, based on thermal, moisture, and other characteristics. The differences in how frequently these different weather types occur in different phases of the North Atlantic Oscillation (NAO) and Pacific,North American (PNA) teleconnection patterns is assessed, for Canadian stations from 1953 to 1993, and for US stations from 1950 to 1999. For PNA, a significant shift in the transitional frequency is observed, suggesting changes in storm track. Concomitantly, a large shift in Dry Polar and Moist Tropical frequencies is observed across the continent. Across the West, in +PNA wintertime months far fewer Dry Polar days are observed. Across the eastern USA, these polar intrusions are more common, and Moist Tropical is diminished significantly. The frequency of the transitional situation is also correlated with NAO phase, with differences as large as a factor of two across much of Canada and the northern USA. In northeastern Canada, there is a large replacement of Moist Polar conditions with Dry Polar conditions during +NAO. Farther south, however, across the eastern USA, both polar weather types occur much less often with +NAO. Although previous research has discovered eastern North American connections to the NAO, this research has shown that the connections often extend into the interior West during much of the year. Particularly strong in the spring, Dry Tropical conditions are much more common with +NAO throughout much of the continent, as far west as the Great Basin. Copyright © 2003 Royal Meteorological Society. [source] Klimapolitik: Kyoto-Protokoll und Emissionshandel für CO2 -Zertifikate in der EU1PERSPEKTIVEN DER WIRTSCHAFTSPOLITIK, Issue 3 2005Wolfgang Ströbele Also every economist knows that the institutional conditions and the rules of the game are important. This basic idea stood behind the introduction of a CO2 -emissions trading system within the European Community starting in 2005. Since the starting point is the Kyoto-protocol with its subset of relevant states involved and the rules agreed upon there, one must ask whether the EU CO2-trading system is really an instrument that helps to reach the Kyoto goals more efficiently. A positive answer to this question is very doubtful. The new European subsystem is only valid for CO2 while Kyoto knows six greenhouse gases, the EU trading periods are 2005,2007 and 2008,2012 while Kyoto is only relevant for the second period, the integration with all flexible instruments of Kyoto is not guaranteed from the beginning. The plants involved are power plants and plants with high energy intensity. Since the technological levels of these plants are rather similar in Europe, the difference in marginal abatement cost will not be large enough to offset the rather high transaction cost of the special EU system. Furthermore, the heating systems and small scale plants of industry are not included in the trading system. The same holds true for traffic, households and the service sector. Drawing a borderline between CO2 -policy there and the trading activities will cause inefficiencies. If CO2 -prices are high, the main incentive of the trading system will be a large shift from domestic production to production abroad without any CO2 -restrictions. Leakage-effects will then be dominant. With low CO2 -prices the special European bureaucratic system will not create enough efficiency gains to cover the trading system's cost. [source] Entry and regulation: evidence from health care professionsTHE RAND JOURNAL OF ECONOMICS, Issue 4 2008Catherine Schaumans In many countries, pharmacies receive high regulated markups and are protected from competition through geographic entry restrictions. We develop an empirical entry model for pharmacies and physicians with two features: entry restrictions and strategic complementarities. We find that the entry restrictions have directly reduced the number of pharmacies by more than 50%, and also indirectly reduced the number of physicians by about 7%. A removal of the entry restrictions, combined with a reduction in the regulated markups, would generate a large shift in rents to consumers, without reducing the availability of pharmacies. The public interest motivation for the current regime therefore has no empirical support. [source] Design of change detection algorithms based on the generalized likelihood ratio testENVIRONMETRICS, Issue 8 2001Giovanna Capizzi Abstract A design procedure for detecting additive changes in a state-space model is proposed. Since the mean of the observations after the change is unknown, detection algorithms based on the generalized likelihood ratio test, GLR, and on window-limited type GLR, are considered. As Lai (1995) pointed out, it is very difficult to find a satisfactory choice of both window size and threshold for these change detection algorithms. The basic idea of this article is to estimate, through the stochastic approximation of Robbins and Monro, the threshold value which satisfies a constraint on the mean between false alarms, for a specified window size. A convenient stopping rule, based on the first passage time of an F -statistic below a fixed boundary, is used to terminate the iterative approximation. Then, the window size which produces the most desirable out-of-control ARL, for a fixed value of the in-control ARL, can be selected. These change detection algorithms are applied to detect biases on the measurements of ozone, recorded from one monitoring site of Bologna (Italy). Comparisons of the ARL profiles reveal that the full-GLR scheme provides much more protection than the window-limited GLR schemes against small shifts in the process, but the modified window-limited GLR provides more protection against large shifts. Copyright © 2001 John Wiley & Sons, Ltd. [source] Adaptation of soil microbial communities to temperature: comparison of fungi and bacteria in a laboratory experimentGLOBAL CHANGE BIOLOGY, Issue 12 2009GEMA BÁRCENAS-MORENO Abstract Temperature not only has direct effects on microbial activity, but can also affect activity indirectly by changing the temperature dependency of the community. This would result in communities performing better over time in response to increased temperatures. We have for the first time studied the effect of soil temperature (5,50 °C) on the community adaptation of both bacterial (leucine incorporation) and fungal growth (acetate-in-ergosterol incorporation). Growth at different temperatures was estimated after about a month using a short-term assay to avoid confounding the effects of temperature on substrate availability. Before the experiment started, fungal and bacterial growth was optimal around 30 °C. Increasing soil temperature above this resulted in an increase in the optimum for bacterial growth, correlated to soil temperature, with parallel shifts in the total response curve. Below the optimum, soil temperature had only minor effects, although lower temperatures selected for communities growing better at the lowest temperature. Fungi were affected in the same way as bacteria, with large shifts in temperature tolerance at soil temperatures above that of optimum for growth. A simplified technique, only comparing growth at two contrasting temperatures, gave similar results as using a complete temperature curve, allowing for large scale measurements also in field situations with small differences in temperature. [source] Spatial patterns of kangaroo density across the South Australian pastoral zone over 26 years: aggregation during drought and suggestions of long distance movementJOURNAL OF APPLIED ECOLOGY, Issue 5 2007ANTHONY R. POPLE Summary 1Wildlife surveys usually focus on estimating population size, and management actions such as commercial harvesting, culling and poison baiting are referenced commonly to population size alone, without taking into account the way in which those animals are distributed. This paper outlines how point-based aerial survey data can be converted to continuous density surfaces using spatial analysis techniques. Using this approach, we describe and explore the spatial patterns of density of two species of kangaroos in an area exceeding 200 000 km2 in South Australia over a 26-year period. 2Densities of red and western grey kangaroos were estimated in 2 km2 segments along aerial survey transect lines, yielding point density estimates. Universal kriging provided an unbiased interpolation of these data using the spatial autocorrelation structure described by the semi-variogram. The Getis statistic identified clusters of high and low kangaroo density. 3Considerable year-to-year variation in the spatial patterns of kangaroo density was observed. In many cases, annual rates of increase over large areas were too high to be explained by vital rates alone, implying immigration from surrounding areas. These large shifts in distribution were occasionally to areas that had received better rainfall than the surrounding areas. For both species, there was no obvious local spatial autocorrelation pattern or clustering of kangaroo density beyond that described by average density and the present set of management regions, suggesting the latter are appropriate divisions for harvest management. 4Data for both species fitted the power law relationship extremely well. During dry times, red kangaroos, but not western grey kangaroos, were more aggregated, supporting past ground observations at a fine spatial scale. 5Synthesis and applications. Kriged density surfaces enable estimation of kangaroo density on individual properties, which are the management units at which harvest quotas or culling approvals are allocated. These estimates will be marked improvements over systematic sampling estimates when sampling intensity is low. Predictions of shifts in kangaroo distribution using rainfall or satellite imagery will allow more accurate allocation of harvest quotas. Similarly, predictions of more even kangaroo dispersion following high rainfall will allow managers to anticipate downturns in harvest rate. [source] Social Influence on Political Judgments: The Case of Presidential DebatesPOLITICAL PSYCHOLOGY, Issue 2 2007Steven Fein Four experiments investigated the extent to which judgments of candidate performance in presidential debates could be influenced by the mere knowledge of others' reactions. In Experiments 1 and 2 participants watched an intact version of a debate or an edited version in which either "soundbite" one-liners or the audience reaction to those soundbites were removed. In Experiment 3 participants saw what was supposedly the reaction of their fellow participants on screen during the debate. Participants in Experiment 4 were exposed to the reactions of live confederates as they watched the last debate of an active presidential campaign. In all studies, audience reactions produced large shifts in participants' judgments of performance. The results illustrate the power of social context to strongly influence individuals' judgments of even large amounts of relevant, important information, and they support the categorization of presidential debates as ambiguous stimuli, fertile ground for informational social influence. [source] The evolution of sex pheromones in an ecologically diverse genus of fliesBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2009MATTHEW R. E. SYMONDS In theory, pheromones important in specific mate recognition should evolve via large shifts in composition (saltational changes) at speciation events. However, where other mechanisms exist to ensure reproductive isolation, no such selection for rapid divergence is expected. In Bactrocera fruit flies (Diptera: Tephritidae), males produce volatile chemicals to attract females for mating. Bactrocera species exhibit great ecological diversity, with a wide range of geographical locations and host plants used. They also have other mechanisms, including temporal and behavioural differences, which ensure reproductive isolation. Therefore, we predicted that their sex pheromones would not exhibit rapid divergence at speciation events. In the present study, we tested this idea by combining data on male sex pheromone composition for 19 species of Bactrocera with a phylogeny constructed from DNA sequence data. Analyses of the combined data revealed positive correlations between pheromone differences and nucleotide divergence between species, and between the number of pheromone changes along the phylogeny and the branch lengths associated with these changes. These results suggest a gradual rather than saltational mode of evolution. However, remarkable differences in sex pheromones composition exist, even between closely-related species. It appears therefore that the mode of evolution of sex pheromones in Bactrocera is best described by rapid saltational changes associated with speciation, followed by gradual divergence thereafter. Furthermore, species that do not overlap ecologically are just as different pheromonally as species that do. Thus, large changes in pheromone composition appear to be achieved, even in cases where other mechanisms to ensure reproductive isolation exist. We suggest that these differences are closely associated with rapid changes in host plant use, which is a characteristic feature of Bactrocera speciation. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 594,603. [source] Photophysics of a Series of Efficient Fluorescent pH Probes for Dual-Emission-Wavelength Measurements in Aqueous SolutionsCHEMISTRY - A EUROPEAN JOURNAL, Issue 4 2006Sandrine Charier Dr. Abstract This paper evaluates the 5-aryl-2-pyridyloxazole backbone to engineer donor,acceptor fluorescent pH probes after one- or two-photon absorption. Parent fluorophores, as well as derivatives that can be used to label biomolecules, can be easily obtained in good yields. These molecules exhibit a large one-photon absorption in the near-UV range, and a strong fluorescence emission that covers the whole visible domain. The 5-aryl-2-pyridyloxazole derivatives also possess significant cross sections for two-photon absorption. Upon pyridine protonation, large shifts were observed in the absorption spectra after one- and two-photon excitation, as well as in the emission spectra. This feature was used to measure the pKa of the investigated compounds that range between 2 and 8. In most of the investigated derivatives, the pKa increased upon light excitation and protonation exchanges took place during the lifetime of the excited state, as shown by phase-modulation fluorometry analysis. Several 5-aryl-2-pyridyloxazole derivatives are suggested as efficient probes to reliably measure the pH of aqueous solutions by means of ratiometric methods that are dependent on fluorescence emission. Cet article évalue le squelette 5-aryl-2-pyridyloxazole pour la conception de sondes fluorescentes de pH de type donneur,accepteur après excitation à un ou deux photons. Il est facile d'obtenir avec de bons rendements et en grande quantité les têtes de série tout autant que des dérivés conçus pour effectuer la fonctionnalisation de biomolécules. Ces sondes absorbent intensément la lumière dans le proche UV et présentent une forte émission de fluorescence qui couvre toute l'étendue du domaine visible. Elles possèdent aussi d'appréciables sections efficaces d'absorption à deux photons. La protonation du cycle pyridine s'accompagne de déplacements importants à la fois dans les spectres d'absorption après excitation à un et deux photons, et dans les spectres d'émission. Ces altérations sont utilisées pour mesurer le pKades sondes synthétisées qui s'étage entre 2 et 8. Une étude par fluorimétrie de phase démontre que le pKade la plupart de ces sondes augmente après absorption lumineuse et que des réactions acido,basiques se produisent au cours de la durée de vie de l'état excité. Ce manuscrit démontre que plusieurs 5-aryl-2-pyridyloxazoles constituent des sondes de pH efficaces et fiables pour mesurer le pH en solution aqueuse par analyse ratiométrique en émission. [source] | ||||||||||||||||