Methylene blue sensitized dichromated gelatin holograms: a study of their storage life and reprocessibility

The results of an experimental investigation on the storage life and reprocessibility of methylene blue sensitized dichromated gelatin (MBDCG) holograms are reported. The major conclusions of the investigation are: (i) Storage of MBDCG holograms in normal laboratory conditions for long periods is possible and it diminishes somewhat their diffraction efficiency. (ii) The results on short time storage and long time storage are almost similar, thus indicating that the diffraction efficiency can be stabilized through storage in a relatively short period of time. (iii) The deterioration in the diffraction efficiency on storage is less [D(eta) < 20%] for gratings of low/medium initial efficiency (eta < 70%) and it is more for gratings of high initial efficiency. (iv) About 65-95% restoration of the diffraction efficiency can be accomplished through reprocessing. (v) The restoration of diffraction efficiency is almost perfect [R(eta) > 80%] for gratings of low/medium initial efficiency (eta <75%) whereas it is rather imperfect for gratings having high initial efficiency.

Impact of energy quantisation in single electron transistor island on hybrid complementary metal oxide semiconductor-single electron transistor integrated circuits

For the first time, the impact of energy quantisation in single electron transistor (SET) island on the performance of hybrid complementary metal oxide semiconductor (CMOS)-SET transistor circuits has been studied. It has been shown through simple analytical models that energy quantisation primarily increases the Coulomb Blockade area and Coulomb Blockade oscillation periodicity of the SET device and thus influences the performance of hybrid CMOS-SET circuits. A novel computer aided design (CAD) framework has been developed for hybrid CMOS-SET co-simulation, which uses Monte Carlo (MC) simulator for SET devices along with conventional SPICE for metal oxide semiconductor devices. Using this co-simulation framework, the effects of energy quantisation have been studied for some hybrid circuits, namely, SETMOS, multiband voltage filter and multiple valued logic circuits. Although energy quantisation immensely deteriorates the performance of the hybrid circuits, it has been shown that the performance degradation because of energy quantisation can be compensated by properly tuning the bias current of the current-biased SET devices within the hybrid CMOS-SET circuits. Although this study is primarily done by exhaustive MC simulation, effort has also been put to develop first-order compact model for SET that includes energy quantisation effects. Finally, it has been demonstrated that one can predict the SET behaviour under energy quantisation with reasonable accuracy by slightly modifying the existing SET compact models that are valid for metallic devices having continuous energy states.

Facile hydrothermal synthesis and observation of bubbled growth mechanism in nano-ribbons aggregated microspherical Covellite blue-phosphor

Well uniform microspheres of phase pure Covellite were synthesized through a simple hydrothermal approach using poly vinyl pyrrolidone (PVP) as surfactant. The micro-spheres were constituted of numerous self-organized knitted nano-ribbons of similar to 30 nm thickness. The effect of conc. PVP in the hydrothermal precursor solution on the product morphology was investigated. Based on the out-coming product micro-architecture a growth mechanism was proposed which emphasized bubbled nucleation inside the hydrothermal reactor. In a comparative study on linear optical properties, enhancement of luminescent intensity was observed for nano-ribbon clung microspheres rather than that of agglomerates of distorted particles, which may be attributed to better crystallinity as well as reduced surface defects and ionic vacancies for ribbon-like nano-structures.

Blue mussel beds as biodiversity hotspots on the rocky shores of the northern Baltic Sea

ABSTRACT The Baltic Sea is a vulnerable ecosystem currently undergoing a number of changes, both natural and human induced. The changes are likely to affect the species found on these shores, e.g. their distribution and interactions with other species. Blue mussels (Mytilus trossulus x Mytilus edulis) provide one of the main biogenic hard structures on the shallow shores of the Baltic Sea where they aggregate into dense beds and provide a number of resources for over 40 associated macrofaunal species, thus functioning as ecosystem engineers. The blue mussel, being a marine species, is highly likely to be affected by any changes in sea water salinity, circulation and/or water balance. These changes could trickle down also to affect the associated macrofaunal communities. The aims of this thesis were three-fold: first, I examined and described the macrofaunal communities found within blue mussel patches since the fauna associated with mussel patches had never been described in the study area prior to this thesis. Second, I explored how changes in mussel density, size as well as patch size and shape would affect the mussel communities. Finally, I tested how general landscape theories derived from terrestrial studies function in blue mussel systems. Theories included the structural heterogeneity hypothesis, species-area relationships, edge effects and patch isolation effects. The work shows that blue mussels in the northern Baltic Sea have an indisputable function as diversity hotspots and that the faunal assemblages found in mussel patches are extremely rich and unique. Further on, it shows that changes in mussel biomass, size, patch size and amount of edge have the potential to alter the faunal assemblages and diversity within patches. Finally, it shows that although some landscape theories, such as the structural heterogeneity hypothesis, seem to apply also in blue mussel communities, others cannot be directly applied due to the different prevailing conditions in the study system. This is a pioneering work looking at diversity shaping processes on the rocky shores of the Gulf of Finland, making up over 40% of the total water basin. A focus on niche construction, positive facilitation effects and ecosystem engineering could provide new insights and methods for conservation biology, but before this can be done, we need to fully understand the circumstances under which a species becomes an ecosystem engineer and recognize the systems in which it functions.

Seasonal fluctuations in blue-green algae, especially in heterocystous species in polluted coastal waters off Helsinki city, in the northern part of the Gulf of Finland

Tiivistelmä

Migration-Development Nexus in the Malawian Health Sector: European Union Blue Card – circular migration for development?

The European Union has agreed on implementing the Policy Coherence for Development (PCD) principle in all policy sectors that are likely to have a direct impact on developing countries. This is in order to take account of and support the EU development cooperation objectives and the achievement of the internationally agreed Millennium Development Goals. The common EU migration policy and the newly introduced EU Blue Card directive present an example of the implementation of the principle in practice: the directive is not only designed to respond to the occurring EU labour demand by attracting highly skilled third-country professionals, but is also intended to contribute to the development objectives of the migrant-sending developing countries, primarily through the tool of circular migration and the consequent skills transfers. My objective in this study is to assess such twofold role of the EU Blue Card and to explore the idea that migration could be harnessed for the benefit of development in conformity with the notion that the two form a positive nexus. Seeing that the EU Blue Card fails to differentiate the most vulnerable countries and sectors from those that are in a better position to take advantage of the global migration flows, the developmental consequences of the directive must be accounted for even in the most severe settings. Accordingly, my intention is to question whether circular migration, as claimed, could address the problem of brain drain in the Malawian health sector, which has witnessed an excessive outflow of its professionals to the UK during the past decade. In order to assess the applicability, likelihood and relevance of circular migration and consequent skills transfers for development in the Malawian context, a field study of a total of 23 interviews with local health professionals was carried out in autumn 2010. The selected approach not only allows me to introduce a developing country perspective to the on-going discussion at the EU level, but also enables me to assess the development dimension of the EU Blue Card and the intended PCD principle through a local lens. Thus these interviews and local viewpoints are at the very heart of this study. Based on my findings from the field, the propensity of the EU Blue Card to result in circular migration and to address the persisting South-North migratory flows as well as the relevance of skills transfers can be called to question. This is as due to the bias in its twofold role the directive overlooks the importance of the sending country circumstances, which are known to determine any developmental outcomes of migration, and assumes that circular migration alone could bring about immediate benefits. Without initial emphasis on local conditions, however, positive outcomes for vulnerable countries such as Malawi are ever more distant. Indeed it seems as if the EU internal interests in migration policy forbid the fulfilment of the PCD principle and diminish the attempt to harness migration for development to bare rhetoric.

Pulsed laser deposited ZnO/ZnO:Li multilayer for blue light emitting diodes

Thin films of ZnO, Li doped ZnO (ZLO) and multilayer of ZnO and ZLO (ZnO/ZLO) were grown on silicon and corning glass substrates by pulsed laser deposition technique. Single phase formation and the crystalline qualities of the films were analyzed by X-ray diffraction and Li composition in the film was investigated to be 15 wt% by X-ray photoelectron spectroscopy. Raman spectrum reveals the hexagonal wurtzite structure of ZnO, ZLO and ZnO/ZLO multilayer and confirms the single phase formation. Films grown on corning glass shows more than 80% transmittance in the visible region and the optical band gaps were calculated to be 3.245, 3.26 and 3.22 eV for ZnO, ZLO and ZnO/ZLO, respectively. An efficient blue emission was observed in all films which were grown on silicon (1 0 0) substrate by photoluminescence (PL). PL measurements at different temperatures reveal that the PL emission intensity of ZnO/ZLO multilayer was weakly dependent on temperature as compared to the single layers of ZnO and ZLO and the wavelength of emission was independent of temperature. Our results indicate that ZnO/ZLO multilayer can be used for the fabrication of blue light emitting diodes. (C) 2011 Elsevier B.V. All rights reserved.

Greater Bangalore: Emerging Urban Heat Island

Bangalore is experiencing unprecedented urbanisation and sprawl in recent times due to concentrated developmental activities with impetus on industrialisation for the economic development of the region. This concentrated growth has resulted in the increase in population and consequent pressure on infrastructure, natural resources and ultimately giving rise to a plethora of serious challenges such as climate change, enhanced green-house gases emissions, lack of appropriate infrastructure, traffic congestion, and lack of basic amenities (electricity, water, and sanitation) in many localities, etc. This study shows that there has been a growth of 632% in urban areas of Greater Bangalore across 37 years (1973 to 2009). Urban heat island phenomenon is evident from large number of localities with higher local temperatures. The study unravels the pattern of growth in Greater Bangalore and its implication on local climate (an increase of ~2 to 2.5 ºC during the last decade) and also on the natural resources (76% decline in vegetation cover and 79% decline in water bodies), necessitating appropriate strategies for the sustainable management.

Effectors of Salmonella pathogenicity island 2: An island crucial to the life of Salmonella

The tug of war between a pathogen and its host has been one of the most amazing stories in the field of microbial pathogenesis for ages. The strongest known species of all living organisms is the Homo sapiens and yet it is incredible how a pathogen of the size of few microns is smart enough to defeat this mightiest group of survivors. It is of utmost interest to understand the mechanisms behind the successful habitation of a pathogen inside the ever-resisting and complicate human body. Numerous examples of diseases caused by such pathogens exist which intrigues us to venture in the world of host-pathogen interactions.

Ba(3)(P(1-x)Mn(x)O(4))(2): Blue/green inorganic materials based on tetrahedral Mn(V)

We describe a blue/green inorganic material, Ba(3)(P(1-x)-Mn(x)O(4))(2) (I) based on tetrahedral MnO(4)(3-):3d(2) chromophore. The solid solutions (I) which are sky-blue and turquoise-blue for x <= 0.25 and dark green for x >= 0-50, are readily synthesized in air from commonly available starting materials, stabilizing the MnO(4)(3-) chromophore in an isostructural phosphate host. We suggest that the covalency/ionicity of P-O/Mn-O bonds in the solid solutions tunes the crystal field strength around Mn(V) such that a blue colour results for materials with small values of x. The material could serve as a nontoxic blue/green inorganic pigment.