Geometrical effects on energy transfer in disordered open quantum systems

We explore various design principles for efficient excitation energy transport in complex quantum systems. We investigate energy transfer efficiency in randomly disordered geometries consisting of up to 20 chromophores to explore spatial and spectral properties of small natural/artificial Light-Harvesting Complexes (LHC). We find significant statistical correlations among highly efficient random structures with respect to ground state properties, excitonic energy gaps, multichromophoric spatial connectivity, and path strengths. These correlations can even exist beyond the optimal regime of environment-assisted quantum transport. For random configurations embedded in spatial dimensions of 30 A and 50 A, we observe that the transport efficiency saturates to its maximum value if the systems contain 7 and 14 chromophores respectively. Remarkably, these optimum values coincide with the number of chlorophylls in (Fenna-Matthews-Olson) FMO protein complex and LHC II monomers, respectively, suggesting a potential natural optimization with respect to chromophoric density.Comment: 11 pages, 10 figures. Expanded from the former appendix to arXiv:1104.481

Assessing information value for harnessing knowledge needed for improving decision-making and effectiveness of a government organisation: A Case study of Abu Dhabi Police Force

Due to many adverse consequences of poor decision making in organisations there is a need to focus on the quality of information and knowledge. This research focuses on how to obtain and use, or “harness” knowledge from information in improving organisational decision-making in a civil protection/security organisation to become effective and enter an organisational wide learning spiral. This is necessary in order to gain a high degree of intuitiveness and intelligence and to be effective. The researcher explores how information-knowledge can be processed and converted into deeper level knowledge, while at the same time how to get decision makers to codify knowledge in order to help them to externalise it. In order to achieve this, the “information-space” model was used to show the information-to-knowledge dynamic journey. The research involved using quantitative and qualitative methods. The quantitative approach is used to obtain computable results from key decision-makers, such as senior workers, and test a model derived from the literature. Seventeen hypotheses were proposed based on theory to evaluate the proposed model. Primary data was collected during the empirical phase of the research from 135 respondents. A structural equation model was used and included exogenous and endogenous latent constructs. On the other hand, a use of qualitative research helped to obtain deeper insights into the use of information and knowledge in decision making. It was underpinned by several propositions and its aim was to expose the role of information-knowledge and the creation of a learning organisation. The results of the quantitative approach revealed that twelve hypotheses are positively significant. Two hypotheses have a significant negative impact on other constructs. Additionally, three hypotheses are non-statistically significant. The results reveal some very interesting insights, such as that demographic factors, such as age, level of education, gender, work experience and level of authority, have a significant impact on problem solving and decision making. In terms of type of information, the proprietary and common sense information types have more significance for solving problem and decision making. But, much to the researcher’s surprise, the public information and personal information played a very minor role. On the other hand, the results of the qualitative data collection show how key decision makers made decisions and gained a certain degree of intuition from it. Therefore, this research has met its objective in helping towards improvement in a civil protection/security organisation to become a learning organisation and help it to enter a learning spiral and make continual improvement. Hence, the researcher succeeds in making suitable recommendations to a number of different stakeholders, in particular the civil protection/security organisations to (i) to develop their management and specialist personnel, and, (ii) to have the necessary information management strategy in place that would harness information and help towards (iii) creating an effective and robust knowledge management strategy

Optička svojstva tankih slojeva bismut sulfida Bi2S3

Thin films of bismuth sulfide (Bi2S3) were grown by two deposition techniques, by thermal evaporation and by chemical deposition. The thermally deposited reactions consisted in depositing the individual elements, namely bismuth and sulfur, sequentially from a tungsten boat source and allowing the layers to interdiffuse to form the compound during the heat-treatment. The chemical deposition was based on the reaction between the triethanolamine compex of Bi3+ ions and thiourea in basic media. Scanning electron microscope and X-ray diffraction analysis were made on as-deposited and on annealed films to determine their structure. The different electronic transitions and the optical constants are determined from the transmision and reflection data of these thin films for normal incidence. The optical gaps of Bi2S3 films show a remarkable dependence on the preparation method.Tanki su slojevi bismut sulfida (Bi2S3) načinjeni dvjema metodama, vakuumskim naparavanjem i kemijskim taloženjem. Ti su se slojevi istraživali sustavno-pretražnom elektronskom mikroskopijom i difrakcijom rentgenskog zračenja, prije i nakon termičkog opuštanja. Našao se je niz elektronskih prijelaza i odredile se optičke konstante na osnovi transmisijskih i refleksijskih podataka za okomitu upadnu svjetlost. Optički procijepi Bi2S3 pokazuju priličnu ovisnost o metodi pripremanja

Optička svojstva tankih slojeva bismut sulfida Bi2S3

Thin films of bismuth sulfide (Bi2S3) were grown by two deposition techniques, by thermal evaporation and by chemical deposition. The thermally deposited reactions consisted in depositing the individual elements, namely bismuth and sulfur, sequentially from a tungsten boat source and allowing the layers to interdiffuse to form the compound during the heat-treatment. The chemical deposition was based on the reaction between the triethanolamine compex of Bi3+ ions and thiourea in basic media. Scanning electron microscope and X-ray diffraction analysis were made on as-deposited and on annealed films to determine their structure. The different electronic transitions and the optical constants are determined from the transmision and reflection data of these thin films for normal incidence. The optical gaps of Bi2S3 films show a remarkable dependence on the preparation method.Tanki su slojevi bismut sulfida (Bi2S3) načinjeni dvjema metodama, vakuumskim naparavanjem i kemijskim taloženjem. Ti su se slojevi istraživali sustavno-pretražnom elektronskom mikroskopijom i difrakcijom rentgenskog zračenja, prije i nakon termičkog opuštanja. Našao se je niz elektronskih prijelaza i odredile se optičke konstante na osnovi transmisijskih i refleksijskih podataka za okomitu upadnu svjetlost. Optički procijepi Bi2S3 pokazuju priličnu ovisnost o metodi pripremanja

A Profile of Research in Expert Systems

If the field of Expert Systems (ES) is viewed in terms of a life cycle, the past decade represents the growth phase of its development. Sophistication of ES has increased rapidly, and the use of ES to solve more complex problems has maintained a similar pace. Numerous forces have driven this development including the rapid changes in computer technology. As the field has matured, the body of published research in ES has grown substantially. Through the use of published ES research, this article provides useful answers to these questions. The scope of our study is limited to the description and analysis of ES research in journals published in the United States from 1980 to 1988

Strain Modulated Electronic Properties of Ge Nanowires - A First Principles Study

We used density-functional theory based first principles simulations to study the effects of uniaxial strain and quantum confinement on the electronic properties of germanium nanowires along the [110] direction, such as the energy gap and the effective masses of the electron and hole. The diameters of the nanowires being studied are up to 50 {\AA}. As shown in our calculations, the Ge [110] nanowires possess a direct band gap, in contrast to the nature of an indirect band gap in bulk. We discovered that the band gap and the effective masses of charge carries can be modulated by applying uniaxial strain to the nanowires. These strain modulations are size-dependent. For a smaller wire (~ 12 {\AA}), the band gap is almost a linear function of strain; compressive strain increases the gap while tensile strain reduces the gap. For a larger wire (20 {\AA} - 50 {\AA}), the variation of the band gap with respect to strain shows nearly parabolic behavior: compressive strain beyond -1% also reduces the gap. In addition, our studies showed that strain affects effective masses of the electron and hole very differently. The effective mass of the hole increases with a tensile strain while the effective mass of the electron increases with a compressive strain. Our results suggested both strain and size can be used to tune the band structures of nanowires, which may help in design of future nano-electronic devices. We also discussed our results by applying the tight-binding model.Comment: 1 table, 8 figure

Piloting a manualised weight management programme (Shape Up-LD) for overweight and obese persons with mild-moderate learning disabilities: study protocol for a pilot randomised controlled trial

National obesity rates have dramatically risen over the last decade. Being obese significantly reduces life expectancy, increases the risk of a range of diseases, and compromises quality of life. Costs to both the National Health Service and society are high. An increased prevalence of obesity in people with learning disabilities has been demonstrated. The consequences of obesity are particularly relevant to people with learning disabilities who are already confronted by health and social inequalities. In order to provide healthcare for all, and ensure equality of treatment for people with learning disabilities, services must be developed specifically with this population in mind. The aim of this project is to pilot the evaluation of a manualised weight management programme for overweight and obese persons with mild-moderate learning disabilities (Shape Up-LD)

The olfactory basis of orchid pollination by mosquitoes.

Mosquitoes are important vectors of disease and require sources of carbohydrates for reproduction and survival. Unlike host-related behaviors of mosquitoes, comparatively less is understood about the mechanisms involved in nectar-feeding decisions, or how this sensory information is processed in the mosquito brain. Here we show that Aedes spp. mosquitoes, including Aedes aegypti, are effective pollinators of the Platanthera obtusata orchid, and demonstrate this mutualism is mediated by the orchid's scent and the balance of excitation and inhibition in the mosquito's antennal lobe (AL). The P. obtusata orchid emits an attractive, nonanal-rich scent, whereas related Platanthera species-not visited by mosquitoes-emit scents dominated by lilac aldehyde. Calcium imaging experiments in the mosquito AL revealed that nonanal and lilac aldehyde each respectively activate the LC2 and AM2 glomerulus, and remarkably, the AM2 glomerulus is also sensitive to N,N-diethyl-meta-toluamide (DEET), a mosquito repellent. Lateral inhibition between these 2 glomeruli reflects the level of attraction to the orchid scents. Whereas the enriched nonanal scent of P. obtusata activates the LC2 and suppresses AM2, the high level of lilac aldehyde in the other orchid scents inverts this pattern of glomerular activity, and behavioral attraction is lost. These results demonstrate the ecological importance of mosquitoes beyond operating as disease vectors and open the door toward understanding the neural basis of mosquito nectar-seeking behaviors

Association Between Fulfilment of Expectations and Health-related Quality of Life after Gastric Bypass

The objective was to examine the relationship between fulfilment of expectations and health-related quality of life 4 and 12 months after gastric bypass. A follow-up study based on patients undergoing gastric bypass at Aalborg Hospital – Aarhus University Hospital during February 2008 to December 2009. Health-related quality of life was assessed by Short Form 36 and summarized into the physical component summary and the mental component summary. Information on expectations was questionnaire based. Associations were analysed by linear regression. Included were 87 gastric bypass patients. Compared with patients with fulfilled expectations having expectations partly fulfilled −7.3 (−11.3; −3.3) or not having expectations fulfilled −11.2 (−18.8 ; −3.5) was associated with low a mental component summary 4 months after surgery. At 12 months follow-up patients who reported not to have expectations fulfilled had a low mental component summary score −16.3 (−26.5; −6.2) when compared to their counterparts with fulfilment of expectations. Not having expectations to changes in general well-being fulfilled is associated with low mental component summary. This is seen at follow-up points 4 and 12 months after gastric bypass