Search results for "Size"
showing 10 items of 2718 documents
Total oxidation of propane in vanadia-promoted platinum-alumina catalysts: Influence of the order of impregnation
2015
Differently prepared vanadium promoted Pt/alumina catalysts have been prepared, characterized and tested for propane total oxidation. V-promoted Pt/Al2O3 catalysts have shown remarkably higher catalytic activity than V-free Pt/Al2O3 catalyst. Among V-promoted Pt catalysts that prepared by coimpregnation gave the highest alkane conversions in the whole range of reaction temperatures studied. Factors such as Pt particle size or the oxidation state of platinum do not seem to be the responsible for the enhanced performance. Modification of the redox properties of the catalyst (i.e. high reducibility of vanadium species) likely provoked by the close contact between platinum particles and vanadiu…
Synthesis and preliminary in vivo evaluation of well-dispersed biomimetic nanocrystalline apatites labeled with positron emission tomographic imaging…
2015
In recent years, biomimetic synthetic apatite nanoparticles (AP-NPs), having chemical similarity with the mineral phase of bone, have attracted a great interest in nanomedicine as potential drug carriers. To evaluate the therapeutic perspectives of AP-NPs through the mechanisms of action and organs they interact with, the noninvasive monitoring of their in vivo behavior is of paramount importance. To this aim, here the feasibility to radiolabel AP-NPs ("naked" and surface-modified with citrate to reduce their aggregation) with two positron emission tomographic (PET) imaging agents ([F-18]NaF and Ga-68-NO(2)AP(BP)) was investigated. [F-18]NaF was used for the direct incorporation of the radi…
Formation and growth of palladium nanoparticles inside porous poly(4-vinyl-pyridine) monitored by operando techniques: The role of different reducing…
2017
In this work we followed the formation of palladium nanoparticles, starting from palladium (II) acetate precursor, inside a poly(4-vinylpyridine-co-divinylbenzene) polymer in presence of different reducing agents. The formation and growth of palladium nanoparticles in presence of H-2 was followed as a function of temperature by simultaneous XANES-SAXS techniques, coupled with DRIFT spectroscopy in operando conditions. It was found that the pyridyl functional groups in the polymer plays a fundamental role in the stabilization of the palladium (II) acetate precursor, as well as in the stabilization of the palladium nanoparticles. The effect of a thermal treatment in alcohol (ethanol and 2-pro…
Intellectual Capital – The Key for Sustainable Competitive Advantage for the SME's Sector
2015
Abstract With the adoption of the Lisbon Agenda and its major objective, namely that the EU would become the most dynamic and competitive knowledge based economy in the world, it became clear the Small and Medium Enterprises (SME's) are the especially affected by these plans, because they represent the driving force for the European economy. In this context of creating and maintaining a competitive advantage for the SME's, it is crucial for them to make good use of the intellectual capital of their employees, in an efficient and proficient manner, in order to increase their potential for innovation. The aim of this article is to show, through an original argumentation, based on the analysis…
Genomic divergence landscape in recurrently hybridizing Chironomus sister taxa suggests stable steady state between mutual gene flow and isolation
2021
Abstract Divergence is mostly viewed as a progressive process often initiated by selection targeting individual loci, ultimately resulting in ever increasing genomic isolation due to linkage. However, recent studies show that this process may stall at intermediate stable equilibrium states without achieving complete genomic isolation. We tested the extent of genomic isolation between two recurrently hybridizing nonbiting midge sister taxa, Chironomus riparius and Chironomus piger, by analyzing the divergence landscape. Using a principal component‐based method, we estimated that only about 28.44% of the genomes were mutually isolated, whereas the rest was still exchanged. The divergence land…
Pareto or log-normal? A recursive-truncation approach to the distribution of (all) cities
2012
Traditionally, it is assumed that the population size of cities in a country follows a Pareto distribution. This assumption is typically supported by finding evidence of Zipf's Law. Recent studies question this finding, highlighting that, while the Pareto distribution may fit reasonably well when the data is truncated at the upper tail, i.e. for the largest cities of a country, the log-normal distribution may apply when all cities are considered. Moreover, conclusions may be sensitive to the choice of a particular truncation threshold, a yet overlooked issue in the literature. In this paper, then, we reassess the city size distribution in relation to its sensitivity to the choice of truncat…
Time-delay control for stabilization of the Shapovalov mid-size firm model
2020
Control and stabilization of irregular and unstable behavior of dynamic systems (including chaotic processes) are interdisciplinary problems of interest to a variety of scientific fields and applications. Using the control methods allows improvements in forecasting the dynamics of unstable economic processes and offers opportunities for governments, central banks, and other policy makers to modify the behaviour of the economic system to achieve its best performance. One effective method for control of chaos and computation of unstable periodic orbits (UPOs) is the unstable delay feedback control (UDFC) approach, suggested by K. Pyragas. This paper proposes the application of the Pyragas' me…
Multiple-batch spawning: a risk-spreading strategy disarmed by highly intensive size-selective fishing rate
2022
Can the advantage of risk-managing life-history strategies become a disadvantage under human-induced evolution? Organisms have adapted to the variability and uncertainty of environmental conditions with a vast diversity of life-history strategies. One such evolved strategy is multiple-batch spawning, a spawning strategy common to long-lived fishes that ‘hedge their bets' by distributing the risk to their offspring on a temporal and spatial scale. The fitness benefits of this spawning strategy increase with female body size, the very trait that size-selective fishing targets. By applying an empirically and theoretically motivated eco-evolutionary mechanistic model that was parameterized for …
Sample allocation for efficient model-based small area estimation
2017
We present research results on sample allocations for efficient model-based small area estimation in cases where the areas of interest coincide with the strata. Although model-assisted and model-based estimation methods are common in the production of small area statistics, utilization of the underlying model and estimation method are rarely included in the sample area allocation scheme. Therefore, we have developed a new model-based allocation named g1-allocation. For comparison, one recently developed model-assisted allocation is presented. These two allocations are based on an adjusted measure of homogeneity which is computed using an auxiliary variable and is an approximation of the int…
Human disturbance on Polylepis mountain forests in Peruvian Andes
2014
Vuoristot kattavat 20–25 % maapallon pinta-alasta ja niiden alueella kasvaa noin 28 % maapallon metsistä. Vuoristometsät ovat monella tapaa arvokkaita: ne tarjoavat useita ekosysteemipalveluita ja raaka-aineita sekä sisältävät suuren määrän elinympäristöjä ja eliölajeja. Ne ovat kuitenkin myös erittäin haavoittuvaisia. Resurssien optimoimiseksi tutkijat ovat nimenneet maapallolta hotspot-alueita, joilla esiintyy suuri määrä endeemisiä ja uhanalaisia lajeja. Ihmistoiminta vaikuttaa ekosysteemien luonnolliseen tilaan ollen merkittävä uhka hotspot-alueiden lajeille. Lisäksi ekosysteemin pirstaleisuus, laikun koko ja reunavaikutukset voivat vaikuttaa alueen lajirunsauteen ja sukupuuttovauhtiin.…