ATL Satisfiability is Indeed EXPTIME-complete

The alternating-time temporal logic (ATL) of Alur, Henzingerand Kupferman is being increasingly widely applied in the specificationand verification of open distributed systems and game-like multi-agentsystems. In this article, we investigate the computational complexityof the satisfiability problem for ATL. For the case where theset of agents is fixed in advance, this problem was settledat EXPTIME-complete in a result of van Drimmelen. If the setof agents is not fixed in advance, then van Drimmelen's constructionyields a 2EXPTIME upper bound. In this article, we focus onthe latter case and define three natural variations of the satisfiabilityproblem. Although none of these variations fixes the set ofagents in advance, we are able to prove containment in EXPTIMEfor all of them by means of a type elimination construction—thusimproving the existing 2EXPTIME upper bound to a tight EXPTIMEone.     

Experimental analysis of the efficiency of heterostructure GaAsAlGaAs solar cells

Some years ago Multiple Quantum Wells (MQW) solar cells were introduced as an alternative to obtain high efficiencies. Based on the simple Shockley diode model, the short-circuit current could be increased without loss in the open-circuit voltage. Applying the Detailed Balance Theory, including radiative recombination in the i-region, leads to less optimistic predictions of the limiting efficiency of MQW cells. We present an experimental study in order to compare the efficiency of MQW solar cells with heterostructure cells with graded Al compositions and single bandgap solar cells. Compared to the homojunction AlGaAs cell, an increase of the short-circuit current is observed by the incorporation of GaAs in the i-region. However, the open-circuit voltage is reduced by the implementation of GaAs, due to an increase of the non-radiative recombination current. To estimate the maximum possible open-circuit voltage, the radiative recombination current is determined by measuring the light emission as a function of the applied voltage. From this experiment we conclude that the maximum possible open-circuit voltage of all the heterostructure cells is considerably lower than the homogeneous AlGaAs cell and close to the value of the GaAs cell, showing the relation between the open-circuit voltage and the smallest bandgap in the cell. The measured curves can be well predicted by calculations based on the Detailed Balance Theory. We find no principal advantage of MQW cells over cells with graded composition or single bandgap cells.     

Detection of Escherichia coli O157:H7, Salmonella typhimurium, and Legionella pneumophila in water using a flow-through chemiluminescence microarray readout system

Fast, sensitive, and especially, multianalyte test systems are currently of high interest for the monitoring and quality control of drinking water, since traditional microbiological methods are labor intensive and can take days until a response is achieved. In this study, the first flow-through chemiluminescence microarray was developed and characterized for the rapid and simultaneous detection of Escherichia coli O157:H7, Salmonella typhimurium, and Legionella pneumophila in water samples using a semiautomated readout system. Therefore, antibody microarrays were produced on poly(ethylene glycol)-modified glass substrates by means of a contact arrayer. For capturing bacteria, species-specific polyclonal antibodies were used. Cell recognition was carried out by binding of species-specific biotinylated antibodies. Chemiluminescence detection was accomplished by a streptavidin-horseradish peroxidase (HRP) catalyzed reaction of luminol and hydrogen peroxide. The chemiluminescence reaction that occurred was recorded by a sensitive charge-coupled device (CCD) camera. The overall assay time was 13 min, enabling a fast sample analysis. In multianalyte experiments, the detection limits were 3 x 10(6), 1 x 10(5), and 3 x 10(3) cells/mL for S. typhimurium, L. pneumophila, and E. coli O157:H7, respectively. Quantification of samples was possible in a wide concentration range with good recoveries. The presented system is well suited for quick and automatic water analysis.     

A method for landscape regionalization based on fuzzy membership signatures

The aim of this paper is to present a new method for regionalization that can be used in landscape analysis and planning. The approach in this study concentrates on the possibility to use membership functions developed from training sites as a mean to characterize whole regions. Instead of traditional classification routines a fuzzy method was developed. The method is described with an example from a study area located in Sweden. Pre-classified and unclassified satellite data were used in the study. The frequency distribution of three land cover types was calculated for three different training sites. The frequency distributions were transformed into membership functions. As such they describe the graded membership for every frequency pixel to all the training sites. Thereafter, were the membership images combined through a weighted linear combination. The result shows the membership for every location in the study area to one of the training sites. The images were also classified into one resulting image showing the crisp regions of the study area. An accuracy assessment of the method was performed. The result showed an overall classification accuracy of 86% compared to existing regional divisions of the study area.     

Investigation of product quality, sensory profile and ultrastructure of breads made from a range of commercial gluten-free flours compared to their wheat counterparts

Bread is a major staple food consumed daily in all parts of the world. A significant part of the human population cannot tolerate gluten, a storage protein found in wheat, rye and barley, and therefore, products made from alternative cereals are required. During this study, the bread-making potential of seven gluten-free flours, wheat and wholemeal wheat flour was compared. Fermentation potential of the different flours was determined, showing that dough development height of gluten-free and wholemeal wheat samples was lower than for wheat and oat flour. Apart from standard bread quality parameters such as loaf-specific volume and physical crumb texture, also water activity and shelf life have been determined. The shelf life of gluten-free breads was reduced compared to wheat bread. Aroma profiles were evaluated by a trained panel. Wheat, oat and wholemeal wheat breads were liked moderately, while the remaining samples had lower liking scores. Crumb grain characteristics were investigated using image analysis, and microstructure was observed by scanning electron microscopy. Overall, only breads produced from oat flour were of similar quality to wheat bread, and the utilization of buckwheat, rice, maize, quinoa, sorghum and teff flours resulted in breads of inferior quality.     

Mechanical properties of a Gelidium corneum edible film containing catechin and its application in sausages

ABSTRACT:  We prepared an edible Gelidium corneum (GC) film containing catechin and examined the microbial growth and quality change during storage of sausages packaged with the film. Incorporation of catechin in the film improved film tensile strength and water vapor permeability. The film's antimicrobial activity against Eschericha coli O157:H7 increased with increasing catechin concentrations and resulted in a decrease in the populations of the bacteria by 1.93 log CFU/g at 150 mg of catechin. For the sausage samples inoculated with E. coli O157:H7 and Listeria monocytogenes, the samples packed with the GC film showed a decrease in populations of E. coli O157:H7 and L. monocytogenes by 1.81 and 1.44 log CFU/g, respectively, compared to the control after 5 d of storage. In addition, the sausage samples packed with the GC film had lower degrees of lipid oxidation. The results suggest that sausages can be packed with GC film to extend shelf life.     

Wavelength controlled InAs/InP quantum dots for telecom laser applications

This article reviews the recent progress in the growth and device applications of InAs/InP quantum dots (QDs) for telecom applications. Wavelength tuning of the metalorganic vapor-phase epitaxy grown single layer and stacked InAs QDs embedded in InGaAsP/InP (1 0 0) over the 1.55-μm region at room temperature (RT) is achieved using ultra-thin GaAs interlayers underneath the QDs. The GaAs interlayers, together with reduced growth temperature and V/III ratio, and extended growth interruption suppress As/P exchange to reduce the QD height in a controlled way. Device quality of the QDs is demonstrated by temperature-dependent photoluminescence (PL) measurements, revealing zero-dimensional carrier confinement and defect-free InAs QDs, and is highlighted by continuous-wave ground-state lasing at RT of narrow ridge-waveguide QD lasers, exhibiting a broad gain spectrum. Unpolarized PL from the cleaved side, important for realization of polarization insensitive semiconductor optical amplifiers, is obtained from closely stacked QDs due to vertical electronic coupling.