Nonenzymic browning during storage of white hard grape pekmez (Zile pekmezi)

Effects of storage period on hydroxymethylfurfural, pH and colour were studied in white hard grape pekmez (Zile pekmezi), a Turkish traditional product. Pekmez samples were stored at 20 °C for 8 months. Analysis of variance revealed significant differences in hydroxymethylfurfural, pH, L, a and b values (P<0.01) based on storage time.     

Combined forecasts in portfolio optimization: A generalized approach

In this paper a general mathematical model for portfolio selection problem is proposed. By considering a forecasting performance according to the distributional properties of residuals, we formulate an extended mean-variance-skewness model with 11 objective functions. Returns and return errors for each asset obtained using different forecasting techniques, are combined in optimal proportions so as to minimize the mean absolute forecast error. These proportions are then used in constructing six criteria related to the mean, variance and skewness of return forecasts of assets in the future and forecasting errors of returns of assets in the past. The obtained multi-objective model is scalarized by using the conic scalarization method which guarantees to find all non-dominated solutions by considering investor preferences in non-convex multi-objective problems. The obtained scalar problem is solved by utilizing F-MSG algorithm. The performance of the proposed approach is tested on a real case problem generated on the data derived from Istanbul Stock Exchange. The comparison is conducted with respect to different levels of investor preferences over return, variance, and skewness and obtained results are summarized.     

Partial purification of <Emphasis Type="Italic">nigella sativa</Emphasis> L. Seed lipase and its application in hydrolytic reactions. Enrichment of γ-linolenic acid from borage oil

Selective hydrolysis of borage (Borago officinalis L.) oil was catalyzed by two lipase preparations of Nigella sativa L. seeds at 40°C in a mixture of borage oil, water, and hexane. Ammonium sulfate-precipitated lipase (Nigella PL) and lipase partially purified by DEAE-ion exchange chromatography (Nigella CPL) exhibited a negative specificity toward γ-linolenic acid (GLA). Best results were obtained in the experiments conducted with 330 U/g oil of Nigella PL and 200 U/g oil of nigella CPL. When 330 U/g oil of Nigella PL was used, after 8 h the GLA level rose from 21.9% in the starting oil to 29.6 and 41.8% in TAG and DAG fractions of the product mixtures, respectively (1.5-fold enrichment of GLA in the total unhydrolyzed acylglycerol fraction). At 200 U/g oil enzyme concentration of Nigella CPL, after 77 h maximum GLA enrichment was observed in the DAG fraction. The GLA content of the DAG increased to 34.6%, corresponding to almost 1.6-fold enrichment. The relative inability of Nigella sativa lipase(s) to hydrolyze γ-linolenoyl moieties of TAG can be used for the enrichment of this acid in the unhydrolyzed acylglycerol fractions of GLA-containing oils.     

Optimal tuning of PI speed controller coefficients for electric drives using neural network and genetic algorithms

This paper presents a method of tuning Proportional Integral (PI) controller coefficients in the off-line control of a nonlinear system. In this method, the first step is the identification of the system via Artificial Neural Networks (ANNs), using maximum overshoot and settling time obtained from the application circuit for different K_p-K_i pairs. With this in mind, multi-layer ANN, which uses back-propagation of the error algorithm, was used as the learning algorithm. In the second step, the purpose is to find the optimum controller coefficients using the ANN model as the objective function via Genetic Algorithms (GAs). A Digital Signal Processor (DSP-TMS320C50) was used to carry out control applications. The C++ language was used for ANN and GA, and and the Assembly language was used for the DSP. It is determined that maximum overshoot and settling time are very small if the system is controlled by control parameters obtained from the optimization process that uses GA.     

Student selection and assignment methodology based on fuzzy MULTIMOORA and multichoice goal programming

Student selection is a multicriteria decision‐making problem that includes both tangible and intangible factors. In these problems if educational institutions have budget or other different constraints, two problems will exist: which students are the best and how students are assigned to the predefined programs? In this study, an integrated approach of fuzzy MULTIMOORA and multichoice conic goal programming is proposed to consider criteria in choosing the best students and define the optimum assignments among the predefined programs to maximize both the total preference value and total ranking value. The rankings of the students are determined by using fuzzy MULTIMOORA. The rankings of candidates are set as the parameters of the first objective function. The placement preferences of the students according to the predefined programs are considered in the second objective function. The candidates are assigned to their placement preferences both by using multichoice conic goal programming among partner universities according to the objectives and by considering the budget and quota.     

Compact multimodal adaptive-optics spectral-domain optical coherence tomography instrument for retinal imaging

We have developed a compact, multimodal instrument for simultaneous acquisition of en face quasi-confocal fundus images and adaptive-optics (AO) spectral-domain optical coherence tomography (SDOCT) cross-sectional images. The optical system including all AO and SDOCT components occupies a 60x60 cm breadboard that can be readily transported for clinical applications. The AO component combines a Hartmann-Shack wavefront sensor and a microelectromechanical systems-based deformable mirror to sense and correct ocular aberrations at 15 Hz with a maximum stroke of 4 microm. A broadband superluminescent diode source provides 4 mum depth resolution for SDOCT imaging. In human volunteer testing, we observed up to an 8 dB increase in OCT signal and a corresponding lateral resolution of <10 microm as a result of AO correction.     

Recent developments in microgrids and example cases around the world—A review

Climate change concerns due to the rising amounts of the carbon gas in the atmosphere have in the last decade or so initiated a fast pace of technological advances in the renewable energy industry. Such developments in technology and the move towards cleaner sources of energy have made distributed generation (DG) from renewable resources more desirable. However, it is a known fact that rising penetrations of DG can have adverse impacts on the grid structure and its operation. The microgrid concept is a solution proposed to control the impact of DG and make conventional grids more suitable for large scale deployments of DG. Covering many aspects of the power systems and power electronics fields, microgrids have become a very popular research field. This paper reviews the background and the concept of a microgrid, the current status of the literature, on-going research projects, and the relevant standards. It also presents a review of the microgrid pilot projects around the world in further detail and discusses the potential avenues for further research.     

Utilization of hazelnut pellicle in low-fat beef burgers

Hazelnut pellicle was used as a dietary fiber in the production of beef burgers. The effects of hazelnut pellicle addition on proximate composition, pH, cook loss, dimensional changes, color and sensory characteristics of beef burgers were evaluated. Hazelnut pellicle addition affected some quality parameters of beef burgers. The control samples had the lowest moisture and protein contents (P<0.05). The cooking yield and reduction in diameter and thickness of beef burgers improved by the addition of hazelnut pellicle. Beef burgers formulated with hazelnut pellicle had lower L, a and b values than control samples (P<0.05). There were differences among beef burger samples in respect to sensory properties, control samples and 1% and 2% pellicle added samples had high acceptability. The results indicate that, 1-2% hazelnut pellicle can be used as a suitable dietary fiber source in low-fat beef burger production.     

The validity of two versions of the GHQ in the WHO study of mental illness in general health care

BACKGROUND: In recent years the 12-item General Health Questionnaire (GHQ-12) has been extensively used as a short screening instrument, producing results that are comparable to longer versions of the GHQ. METHODS: The validity of the GHQ-12 was compared with the GHQ-28 in a World Health organization study of psychological disorders in general health care. Results are presented for 5438 patients interviewed in 15 centres using the primary care version of the Composite International Diagnostic Instrument, or CIDI-PC. RESULTS: Results were uniformly good, with the average area under the ROC curve 88, range from 83 to 95. Minor variations in the criteria used for defining a case made little difference to the validity of the GHQ, and complex scoring methods offered no advantages over simpler ones. The GHQ was translated into 10 other languages for the purposes of this study, and validity coefficients were almost as high as in the original language. There was no tendency for the GHQ to work less efficiently in developing countries. Finally gender, age and educational level are shown to have no significant effect on the validity of the GHQ. CONCLUSIONS: If investigators wish to use a screening instrument as a case detector, the shorter GHQ is remarkably robust and works as well as the longer instrument. The latter should only be preferred if there is an interest in the scaled scores provided in addition to the total score.     

Oil Content,Oil Yield and Fatty Acid Profile of Groundnut Germplasm in Mediterranean Climates

A high amount of good-quality vegetable oil in seeds has an overwhelming contribution to the groundnut (Arachis hypogaea L.) cultivation throughout the world. In order to take into account great variation in oil characteristics in Arachis subspecies and botanical varieties, 256 groundnut genotypes including ICRISAT’s mini core collection were investigated. Significant variability in oil content (31.7–57.0%) was detected among groundnut genotypes. Oil yield varied from 9.5 to 179.3 kg da^?1 with the average being 67.7 kg da^?1. Significant genotypic differences were also observed for all the fatty acids studied. Oleic and linoleic acids accounted for the major fraction with mean values of 45.3 and 32.1% in the ranges of 35.3–60.9% and 16.1–43.6%, respectively. Significant negative correlation was observed between oleic and linoleic acid. In the present investigation, desirable values were obtained for oil traits which would be useful to develop nutritional and health-beneficial cultivars.