Perfect imaging: they don't do it with mirrors

Imaging with a spherical mirror in empty space is compared with the case when the mirror is filled with the medium of Maxwell's fish eye. Exact time-dependent solutions of Maxwell's equations show that perfect imaging is not achievable with an electrical ideal mirror on its own, but with Maxwell's fish eye in the regime when it implements a curved geometry for full electromagnetic waves

Site Suitability Analysis for Urban Settlements along River Jhelum, Pakistan using GIS and Remote Sensing Techniques

Infrastructure development is critical to the success of economic growth policies. Remote sensing and GIS tools have an important role to play in the development of various urban infrastructures. Due to the rapid growth of urban population and urbanization, it is necessary to find out the site's suitability for sustainable urban development. The main aim of the study is to study the growth and trend of urbanization, as well as to find out the suitable sites for further urban development in northern Punjab, along the river Jhelum, Pakistan. The study illustrates the use of geographic information system (GIS) and Remote Sensing based techniques i.e. Human Natural Environment Index (HNEI) applied with a foundation of Relief Degree of Land Surface (RDLS), Temperature Humidity Index (THI), Water Resource Index (WRI), and Land Cover Index (LCI) for selection of the suitable site for urban settlements along river Jhelum, Pakistan. For this purpose, Toposheet and Landsat satellite data were used to generate various thematic layers using ArcGIS software. The results were generated in form of five categories i.e., highly suitable, moderately suitable, relatively low suitable, low suitable, and non-suitable. The final results indicated that district Sargodha is most suitable for long-term sustainable urban settlements favored by relief, climate, water availability, land cover scenario, and flood hazard-free area. Eventually, a site suitability map is prepared for further urban development. The present study allows the local people as well as urban planners for the appropriate plans of land use planning in sustainable urban development

Impact Assessment of Urban Built-up Area on Groundwater Level of District Faisalabad, Pakistan

This paper attempts to explore the impact of built-up areas on groundwater levels in district Faisalabad.To understand the rate of built-up area expansion and changes in the level of groundwater in the study area, groundwaterdata has been acquired from the Land Reclamation Department for all tehsils in district Faisalabad. This study wasconducted to assess spatial and temporal variation of groundwater level because of the built-up area change. Descriptivestatistics (Scatter Plot correlation technique) have been applied to figure out changes in groundwater levels. Furthermore,some built-up area extraction methods have been incorporated that are always found to be effective tools for theassessment of built-up area change. The spatial analysis tool Spline has applied to 79 bore points in all tehsils of districtFaisalabad. Results clearly show that a built-up increase of 41 km2in Faisalabad city is causing 1-foot depletion ingroundwater as compared to other tehsils, where a built-up increase is negligible. Such research studies of groundwaterchanges would assist the planners to adopt effective sustainable measures

Urban Floods and Suitability Analysis of Rainwater Harvesting Potential Areas in Lahore City, Pakistan

There is a growing threat of urban flooding, particularly in Pakistan that needs attention and requires effective management strategies. The chief trigger for urban flooding is the rapid and unplanned urbanization in areas where impermeable surface inhibits rainwater diffusion and changes the natural water flow. In many developed countries, a technique of rainwater harvesting is implemented as a sustainable strategy to manage urban stormwater. Most studies and projects chiefly focused on the potential use of the Rainwater harvesting technique for water conservation in arid and semi-arid climates. In the present work, GIS and remote sensing methodologies are utilized for the suitability of rainwater harvesting structures. This study was conducted in Lahore, the second most populated city of Pakistan and the capital of Punjab. Generally, the water harvesting technique depends on topographical areas with water accumulation, where there is an availability of open spaces in the form of green areas and barren lands, rainfall, drainage network density, and rainfall distribution, particularly in the urban environment. The SRTM DEM data were used for finding high water accumulated areas, and the Landsat OLI image is used to retrieve land use information i.e. vacant land and open green spaces, existing drainage network density, and rainfall distribution. All these layers were integrated through AHP to detect the potentially suitable sites for the construction of rainwater harvesting structures. Results concluded 94 suitable sites with categorization from highly to critically suitable for the construction of rainwater harvesting structures in which 6 were highly suitable areas in Data Gunj Bakhsh Town and Ravi Town. Besides, residential areas are having a maximum site suitability percentage, followed by roads, agricultural and open spaces in the area under consideration. Considering the suitable sites, further rainwater harvesting methods can be identified in the study area to alleviate urban flooding and improve the urban environment

An Extensive Study of User Identification via Eye Movements across Multiple Datasets

Several studies have reported that biometric identification based on eye movement characteristics can be used for authentication. This paper provides an extensive study of user identification via eye movements across multiple datasets based on an improved version of method originally proposed by George and Routray. We analyzed our method with respect to several factors that affect the identification accuracy, such as the type of stimulus, the IVT parameters (used for segmenting the trajectories into fixation and saccades), adding new features such as higher-order derivatives of eye movements, the inclusion of blink information, template aging, age and gender.We find that three methods namely selecting optimal IVT parameters, adding higher-order derivatives features and including an additional blink classifier have a positive impact on the identification accuracy. The improvements range from a few percentage points, up to an impressive 9 % increase on one of the datasets.Comment: 11 pages, 5 figures, submitted to Signal Processing: Image Communicatio

Quasiparticle spectra from a non-empirical optimally-tuned range-separated hybrid density functional

We present a method for obtaining outer valence quasiparticle excitation energies from a DFT-based calculation, with accuracy that is comparable to that of many-body perturbation theory within the GW approximation. The approach uses a range-separated hybrid density functional, with asymptotically exact and short-range fractional Fock exchange. The functional contains two parameters - the range separation and the short-range Fock fraction. Both are determined non-empirically, per system, based on satisfaction of exact physical constraints for the ionization potential and many-electron self-interaction, respectively. The accuracy of the method is demonstrated on four important benchmark organic molecules: perylene, pentacene, 3,4,9,10-perylene-tetracarboxylic-dianydride (PTCDA) and 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA). We envision that for finite systems the approach could provide an inexpensive alternative to GW, opening the door to the study of presently out of reach large-scale systems

Thoughts on Quorum Sensing and Fungal Dimorphism

Farnesol has been best studied for its role in regulating fungal dimorphism. However, farnesol is also a lipid and in this review we analyze data relevant to farnesol’s function and synthesis from the perspective of farnesol and bacterial endotoxins acting as membrane active compounds. This analysis implicates the possible roles of: (1) endotoxins in the regulation of farnesol production by C. albicans; (2) farnesol in the interactions between C. albicans and the host during disseminated infections; and (3) ubiquinones in the mechanisms for unusually high resistance to farnesol by some C. albicans cell types. Finally we discuss the implications that the use of farnesol as both a signaling molecule and to antagonize competing microbials species has for the regulation of HMG-CoA reductase, the enzyme that is the usual rate limiting step in sterol/lipid synthesis

Thoughts on Quorum Sensing and Fungal Dimorphism

Farnesol has been best studied for its role in regulating fungal dimorphism. However, farnesol is also a lipid and in this review we analyze data relevant to farnesol’s function and synthesis from the perspective of farnesol and bacterial endotoxins acting as membrane active compounds. This analysis implicates the possible roles of: (1) endotoxins in the regulation of farnesol production by C. albicans; (2) farnesol in the interactions between C. albicans and the host during disseminated infections; and (3) ubiquinones in the mechanisms for unusually high resistance to farnesol by some C. albicans cell types. Finally we discuss the implications that the use of farnesol as both a signaling molecule and to antagonize competing microbials species has for the regulation of HMG-CoA reductase, the enzyme that is the usual rate limiting step in sterol/lipid synthesis