256 research outputs found
On the optical properties of Ag^{+15} ion-beam irradiated TiO_{2} and SnO_{2} thin films
The effects of 200-MeV Ag^{+15} ion irradiation on the optical properties of
TiO_{2} and SnO_{2} thin films prepared by using the RF magnetron sputtering
technique were investigated. These films were characterized by using UV-vis
spectroscopy, and with increasing irradiation fluence, the transmittance for
the TiO_{2} films was observed to increase systematically while that for
SnO_{2} was observed to decrease. Absorption spectra of the irradiated samples
showed minor changes in the indirect bandgap from 3.44 to 3.59 eV with
increasing irradiation fluence for TiO_{2} while significant changes in the
direct bandgap from 3.92 to 3.6 eV were observed for SnO_{2}. The observed
modifications in the optical properties of both the TiO_{2} and the SnO_{2}
systems with irradiation can be attributed to controlled structural
disorder/defects in the system.Comment: 6 pages, ICAMD-201
Resolved quadrupolar transition in TiO2
We report an investigation of the direct forbidden absorption edge of TiO2. For the first time we have resolved the weak quadrupolar 1s exciton and measured its binding energy. Taking into account polaron effects, we estimated the bare electron effective mass in the Γ1 minimum of the conduction band and obtained a fairly reasonable value of 3m0
Tackling the undeclared economy in the European Union: an evaluation of the tax morale approach
To evaluate a new approach towards tackling the undeclared economy which views participants as social actors rather than rational economic actors, this paper reports evidence from 27,563 face-to-face interviews conducted across the European Union during 2013. Multilevel logistic regression analysis reveals a strong association between participation in undeclared work and the level of tax morale. Finding that higher tax morale (and thus a lower propensity to engage in undeclared work) is strongly correlated with greater levels of state intervention but also with individual-level characteristics such as gender, age, education and employment status, the paper concludes not only by confirming a political economy approach and refuting modernization and neo-liberal explanations and remedies, but also by revealing for the first time the importance of solutions not so far considered, including improving educational attainment, older citizens mentoring for younger people, and improving women’s participation in the labour force
‘The price is different depending on whether you want a receipt or not’: examining the purchasing of goods and services from the informal economy in South-East Europe
Research on the informal economy has largely focussed on supply-side issues, addressing questions like what motivates individuals to work in the informal economy and how can governments tackle this phenomenon. To date, much less attention has been given to demand-side aspects, examining issues around who purchases goods and services from the informal economy, why, and to what extent there are variations according to demographic, socio-economic and geographic dimensions. This paper addresses this imbalance by examining the purchasing of goods and services from the informal economy in South-East Europe. Firstly, this paper identifies the prevalence of such informal purchasing in South-East Europe as well as who undertakes such purchasing. Next, it examines the relative significance of cost factors, social factors and failures in the formal economy, in motivating such purchasing. Finally, it explores variability in the significance of these motivators based on individual-level factors, within and across three South-East European countries
Differences between <i>Trypanosoma brucei gambiense</i> groups 1 and 2 in their resistance to killing by Trypanolytic factor 1
<p><b>Background:</b> The three sub-species of <i>Trypanosoma brucei</i> are important pathogens of sub-Saharan Africa. <i>T. b. brucei</i> is unable to infect humans due to sensitivity to trypanosome lytic factors (TLF) 1 and 2 found in human serum. <i>T. b. rhodesiense</i> and <i>T. b. gambiense</i> are able to resist lysis by TLF. There are two distinct sub-groups of <i>T. b. gambiense</i> that differ genetically and by human serum resistance phenotypes. Group 1 <i>T. b. gambiense</i> have an invariant phenotype whereas group 2 show variable resistance. Previous data indicated that group 1 <i>T. b. gambiense</i> are resistant to TLF-1 due in-part to reduced uptake of TLF-1 mediated by reduced expression of the TLF-1 receptor (the haptoglobin-hemoglobin receptor (<i>HpHbR</i>)) gene. Here we investigate if this is also true in group 2 parasites.</p>
<p><b>Methodology:</b> Isogenic resistant and sensitive group 2 <i>T. b. gambiense</i> were derived and compared to other T. brucei parasites. Both resistant and sensitive lines express the <i>HpHbR</i> gene at similar levels and internalized fluorescently labeled TLF-1 similar fashion to <i>T. b. brucei</i>. Both resistant and sensitive group 2, as well as group 1 <i>T. b. gambiense</i>, internalize recombinant APOL1, but only sensitive group 2 parasites are lysed.</p>
<p><b>Conclusions:</b> Our data indicate that, despite group 1 <i>T. b. gambiense</i> avoiding TLF-1, it is resistant to the main lytic component, APOL1. Similarly group 2 <i>T. b. gambiense</i> is innately resistant to APOL1, which could be based on the same mechanism. However, group 2 <i>T. b. gambiense</i> variably displays this phenotype and expression does not appear to correlate with a change in expression site or expression of <i>HpHbR</i>. Thus there are differences in the mechanism of human serum resistance between <i>T. b. gambiense</i> groups 1 and 2.</p>
Explaining participation in the informal economy: An institutional incongruence perspective
Drawing inspiration from institutional theory, a small sub-stream of literature has proposed that participation in the informal economy arises from the lack of alignment of a society’s formal institutions (i.e. its codified laws and regulations) with its informal institutions (i.e. the norms, values and beliefs of its population). To further advance this explanation, this article reports a 2013 Eurobarometer survey involving 27,563 face-to-face interviews across 28 European countries. The finding is that there is a strong association between the degree to which formal and informal institutions are unaligned and participation in the informal economy. The greater is the asymmetry between the formal and informal institutions, the more likely is participation in the informal economy at the individual-, population group- and country-level. A new policy approach for tackling the informal economy which focuses upon reducing this institutional incongruence is then discussed
Population genetics of trypanosoma brucei rhodesiense: clonality and diversity within and between foci
African trypanosomes are unusual among pathogenic protozoa in that they can undergo their complete morphological life cycle in the tsetse fly vector with mating as a non-obligatory part of this development. Trypanosoma brucei rhodesiense, which infects humans and livestock in East and Southern Africa, has classically been described as a host-range variant of the non-human infective Trypanosoma brucei that occurs as stable clonal lineages. We have examined T. b. rhodesiense populations from East (Uganda) and Southern (Malawi) Africa using a panel of microsatellite markers, incorporating both spatial and temporal analyses. Our data demonstrate that Ugandan T. b. rhodesiense existed as clonal populations, with a small number of highly related genotypes and substantial linkage disequilibrium between pairs of loci. However, these populations were not stable as the dominant genotypes changed and the genetic diversity also reduced over time. Thus these populations do not conform to one of the criteria for strict clonality, namely stability of predominant genotypes over time, and our results show that, in a period in the mid 1990s, the previously predominant genotypes were not detected but were replaced by a novel clonal population with limited genetic relationship to the original population present between 1970 and 1990. In contrast, the Malawi T. b. rhodesiense population demonstrated significantly greater diversity and evidence for frequent genetic exchange. Therefore, the population genetics of T. b. rhodesiense is more complex than previously described. This has important implications for the spread of the single copy T. b. rhodesiense gene that allows human infectivity, and therefore the epidemiology of the human disease, as well as suggesting that these parasites represent an important organism to study the influence of optional recombination upon population genetic dynamics
Vietnam-EU Free Trade Agreement: Impact and Policy Implications for Vietnam
On 4 August 2015, after three years and several rounds of negotiation, the European Union –Vietnam Free Trade Agreement officially established principles for the basic content of the
Agreement. This study aims to analyse impact of Vietnam-EU FTA on bilateral trade of Vietnam. By using a gravity model and a panel data analysis, we show that the reduction of tariffs in the framework of the FTA will have a positive impact on bilateral trade between Vietnam and the EU. In addition, Vietnam-EU FTA will offer many new opportunities but it also challenges for Vietnam. Based on these analyses, this paper proposes some recommendations for Vietnam to benefit more the Vietnam-EU FTA
Characterization of TiO2 nanoparticles in langmuir-blodgett films
In this work we have synthesized TiO2 nanoparticles, using either a sol–gel base catalysed process in the interior of CTAB reversed micelles (TiO2 CTAB sol), or the
neutralization of a TiO2/H2SO4 solution in the interior of AOT reversed micelles. From the absorption and emission data of the TiO2 nanoparticles it is possible to conclude that
in the sol–gel route there remains alkoxide groups in the structure, originating transitions lower than the energy gap of TiO2 semiconductor. These transitions disappear in the neutralization procedure, where the alkoxide groups are absent in the structure. We have assigned the observed indirect
and direct optical transitions according to the anatase band structure. TiO2 Langmuir-Blodgett (LB) films were prepared either by direct deposition of titanium isopropoxide or by deposition of the TiO2 CTAB sol. These films showed photoluminescence, which was attributed to band-gap emission and to surface recombination of defect states
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