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There is no doubt that the most important activity In schools and universities is conducting classes and lectures to their students. Preparation of timetables is a major task confronted by the management every year. A lot of time is spent on this exercise, yet the end result would be far from satisfactory. In this paper, we draw attention to the different approaches of solution to this problem and the need to look for new directions of research.

University admissions for professional degree programmes has become very competitive in many countries in the world. While students have to score high aggregate of marks at the university entrance examinations, other criteria may also have to be met. As a result, additional private coaching outside the normal high school system is being sought by the students. In certain countries private coaching system which uses modern technology and distance education has become a thriving business. In this paper, the consequences of this trend are discussed while paying attention to a study conducted in Sri Lanka. Remedial measures for the Sri Lankan situation are proposed which could be applicable to other countries as well.

Flavonol glycosides in tea leaves have been quantified as aglycones, quercetin, myricetin, and kaempferol. Occurrence of the said compounds was reported in fruits and vegetable for a long time in association with the antioxidant potential. However, data on flavonols in tea were scanty and, hence, this study aims to envisage the flavonol content in a representative pool of accessions present in the Sri Lankan tea germplasm. Significant amounts of myricetin, quercetin, and kaempferol have been detected in the beverage type tea accessions of the Sri Lankan tea germplasm. This study also revealed that tea is a good source of flavonol glycosides. The Camellia sinensis var. sinensis showed higher content of myricetin, quercetin, and total flavonols than var. assamica and ssp. lasiocalyx. Therefore flavonols and their glycosides can potentially be used in chemotaxonomic studies of tea germplasm. The nonbeverage type cultivars, especially Camellia rosaflora and Camellia japonica Red along with the exotic accessions resembling China type, could be useful in future germplasm studies because they are rich sources of flavonols, namely, quercetin and kaempferol, which are potent antioxidants. The flavonol profiles can be effectively used in choosing parents in tea breeding programmes to generate progenies with a wide range of flavonol glycosides.

Chemical analysis of the Sri Lankan tea (Camellia sinensis, L.) germplasm would immensely contribute to the success of the tea breeding programme. However, the polyphenols, particularly catechins (flavan-3-ols), are readily prone to oxidation in the conventional method of sample preparation. Therefore, optimization of the present sample preparation methodology for the profiling of metabolites is much important. Two sample preparation methodologies were compared, fresh leaves (as in the conventional procedures) and freeze-dried leaves (a new procedure), for quantification of major metabolites by employing two cultivars, one is known to be high quality black tea and the other low quality black tea. The amounts of major metabolites such as catechins, caffeine, gallic acid, and theobromine, recorded in the new sampling procedure via freeze-dried leaves, were significantly higher than those recorded in the conventional sample preparation procedure. Additionally new method required less amount of leaf sample for analysis of major metabolites and facilitates storage of samples until analysis. The freeze-dried method would be useful for high throughput analysis of large number of samples in shorter period without chemical deterioration starting from the point of harvest until usage. Hence, this method is more suitable for metabolite profiling of tea as well as other phenol rich plants.

High-current dc thyristor circuit breaker (t.c.b.) devices, based on the parallel capacitor-current commutation-forced turn-off principle, require very large capacitors to effect correct operation as fault-current interrupters in electrical circuits. The commutation capacitors of t.c.b. devices that interrupt current in a single switching operation absorb virtually all the electromagnetic energy stored in circuits, where they operate during the single switching process. These device types interrupt current extremely fast, but because of the scale of the energy transfer to the commutation capacitor, they are especially prone to producing short-duration switching overvoltages of excessive magnitude. A novel t.c.b. device involving two switching operations or stages is presented and analyzed. With this device type, the circuit-stored energy is transferred to the commutation capacitor in two stages, which, in so doing, produces significantly lower switching overvoltages than the conventional 'single-stage' t.c.b. device. Results of a range of tests on a low-voltage two-stage t.c.b. device and a high-power-prototype version are given together with the basis for determining their optimum design criteria. Comparative simulation studies are also provided. Finally, the limitations of t.c.b. devices are examined and discussed in conjunction with cost comparisons and their merits and limitations for typical applications. Index Terms - DC circuit breakers, dc electrical-protection systems, dc-traction systems, thyristor circuit breaker, thyristor switch.

On rare occasions, differentiated thyroid carcinoma causes tumor thrombosis in the great veins. Multimodality treatment with surgery, radioiodine therapy, and targeted therapies is used to manage tumor thrombosis associated with thyroid malignancies, though no established guidelines exist. We present a woman with a tracer-avid tumor thrombus in the right brachiocephalic vein after surgery for follicular thyroid carcinoma. Follow-up revealed an excellent response after treatment with 131I as a single modality for both remnant and tumor thrombus. [ABSTRACT FROM AUTHOR]

This paper's aim is to recognize offline Hand written Malayalam character in different images using optical character recognition, OCR is achallenging technology and popular of pattern recognition.Using OCR in Malayalam language is more complex because the language contains with largest number of characters among all other Indian languages. In this paper we propose an enhanced approach of offline handwritten characters. The steps in the proposed works are Pre-processing, Segmentation. In pre-processing the method used Otsu, Sauvola and Hybrid method, which is applying dilation on sauvola method. In segmentation we use word level segmentation and character level segmentation. [ABSTRACT FROM AUTHOR]

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Sensory evaluation is of prime importance in the tea industry. The price of tea is predominantly determined by the tea taster's judgement. Hence, statisticians and sensory analysts have significant interest in improving the reliability of sensory panel evaluations. This study suggests a statistical de-biasing approach to improve the agreement of panels of tea tasters by using the Mandel's bundle of lines model. This paper analyses data from a panel of eight experts who evaluated 72 black tea samples collected from 13 different geographical regions of Sri Lanka over a one year (January 2010 - December 2010) period at monthly intervals. The results showed that in only 20 instances out of 72, the intra-class correlation coefficients were greater than 0.5, but after bias correction, 64 instances out of 72 have intra-class correlations greater than 0.5. Therefore, the Mandel's bundle of lines approach improves consensus among the experts by enforcing better statistical calibration. [ABSTRACT FROM AUTHOR]

Tea (Camellia sinensisL.) is well known for its biochemical constituents that define the product quality and confer pest and disease resistance. Seven major metabolites – epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC), epigallocatechin gallate (EGCg), caffeine, theobromine, and gallic acid – of 87 beverage type and six non-beverage type tea accessions from Sri Lankan tea germplasm were profiled using HPLC and LC-MS/MS. All seven metabolites varied widely in the beverage type accessions. The non-beverage types only contained gallic acid and epicatechin. Results prove the presence of high EC and ECg contents in green leaves to be a reliable marker for identifying high-quality black tea-producing accessions. High EC and low EGCg contents in green tea leaves appear to enhance traits of resistance to blister blight disease. Significant variations detected in theobromine, caffeine, and total polyphenol content define the affinity of germplasm to the main three tea taxa, and we conclude thatC. sinensisssp.lasiocalyxpredominates the Sri Lankan germplasm collection. [ABSTRACT FROM PUBLISHER]

Modular multilevel converters (MMCs) will be extensively used in the high-voltage direct-current transmission networks because of its superior characteristics over line commutated converter. Increasing the reliability of the MMC is directly related to the balancing of the MMC submodule capacitors voltages, which guarantees the proper operation of the converter and lowers the stress on the submodules. This paper presents an adaptive voltage-balancing strategy based on the capacitor voltage estimation, utilizing a hybrid adaptive linear neuron recursive least squares scheme. The proposed strategy eliminates the need of measuring submodules capacitor voltages and associated communication link with the central controller. Furthermore, the estimated capacitor voltages are utilized to detect and localize different types of submodule faults. After isolating the faulty submodules, the proposed fault-tolerant control unit modifies the parameters of the voltage-balancing strategy to overcome the reduction of the active submodules. The dynamic performance of the proposed strategy is investigated, using PSCAD/EMTDC simulations and hardware-in-the-loop real-time simulations, under different normal and faulty operating conditions. The accuracy and the time response of the proposed fault detection and tolerant control units result in stabilizing the operation of the MMC under different types of faults. Consequently, the proposed integrated control strategy improves the reliability of the MMC. [ABSTRACT FROM PUBLISHER]

Flavonol glycosides in tea leaves have been quantified as aglycones, quercetin, myricetin, and kaempferol. Occurrence of the said compounds was reported in fruits and vegetable for a long time in association with the antioxidant potential. However, data on flavonols in tea were scanty and, hence, this study aims to envisage the flavonol content in a representative pool of accessions present in the Sri Lankan tea germplasm. Significant amounts of myricetin, quercetin, and kaempferol have been detected in the beverage type tea accessions of the Sri Lankan tea germplasm. This study also revealed that tea is a good source of flavonol glycosides. The Camellia sinensis var. sinensis showed higher content of myricetin, quercetin, and total flavonols than var. assamica and ssp. lasiocalyx. Therefore flavonols and their glycosides can potentially be used in chemotaxonomic studies of tea germplasm. The nonbeverage type cultivars, especially Camellia rosaflora and Camellia japonica Red along with the exotic accessions resembling China type, could be useful in future germplasm studies because they are rich sources of flavonols, namely, quercetin and kaempferol, which are potent antioxidants. The flavonol profiles can be effectively used in choosing parents in tea breeding programmes to generate progenies with a wide range of flavonol glycosides. [ABSTRACT FROM AUTHOR]

Chemical analysis of the Sri Lankan tea (Camellia sinensis, L.) germplasm would immensely contribute to the success of the tea breeding programme. However, the polyphenols, particularly catechins (flavan-3-ols), are readily prone to oxidation in the conventional method of sample preparation. Therefore, optimization of the present sample preparation methodology for the profiling of metabolites is much important. Two sample preparation methodologies were compared, fresh leaves (as in the conventional procedures) and freeze-dried leaves (a new procedure), for quantification of major metabolites by employing two cultivars, one is known to be high quality black tea and the other low quality black tea. The amounts of major metabolites such as catechins, caffeine, gallic acid, and theobromine, recorded in the new sampling procedure via freeze-dried leaves, were significantly higher than those recorded in the conventional sample preparation procedure. Additionally new method required less amount of leaf sample for analysis of major metabolites and facilitates storage of samples until analysis. The freeze-dried method would be useful for high throughput analysis of large number of samples in shorter period without chemical deterioration starting from the point of harvest until usage. Hence, this method is more suitable for metabolite profiling of tea as well as other phenol rich plants. [ABSTRACT FROM AUTHOR]

Experimental results on atmospheric-pressure arc plasma convolutes in air around a polytetrafluoroethylene cylindrical shroud containing a magnetic field (B-field) producing coil are presented. In this paper, the B-field coil is energized by a current separate from that flowing through the arc, and a separate RLC circuit was connected across the arc gap. Thus the magnitude and time duration of the B-field are independent of the arc current and the high-frequency current oscillations produced by the parallel RLC circuit. Experimental results for the time variation of the current through and voltage across the arc plasma for these different conditions are presented, along with high-speed photographs of the oscillating current arc. The effects of varying the B-field upon plasma pulsations formed by the independent B-field and RLC current oscillations are discussed. [ABSTRACT FROM AUTHOR]

This study proposes a simple topology which consists of a single sinusoidal pulse width modulation (SPWM) inverter and battery banks with wind-driven doubly fed induction generators (DFIGs) to dispatch a controllable power to the grid. The excitation of the rotor is established using an SPWM inverter supplied through a set of batteries with the stator connected to the grid. The proposed system supplies the desired real and reactive power to the grid by appropriately charging/discharging the batteries depending on excess/deficit power from the wind. A closed-loop controller has been developed for this purpose which involves varying the rotor voltage magnitude and frequency. The entire control strategy proposed in this study has been implemented using TMS320LF2407A DSP controller and detailed procedure for such implementation is presented. The steady-state analysis and phasor diagram representation of the system have been developed and presented. Experimental results obtained on a three-phase, four-pole, 50 Hz, 5 kVA DFIG together with the closed-loop controller under steady-state and dynamic operating conditions, confirm the usefulness of the proposed system. The experimental results have been compared with predicted values and a very close agreement between the two is observed. [ABSTRACT FROM AUTHOR]

Tea (Camellia sinensis) is rich in specialized metabolites, especially polyphenolic proanthocyanidins (PAs) and their precursors. To better understand the PA pathway in tea, we generated a complementary DNA library from leaf tissue of the blister blight-resistant tea cultivar TRI2043 and functionally characterized key enzymes responsible for the biosynthesis of PA precursors. Structural genes encoding enzymes involved in the general phenylpropanoid/flavonoid pathway and the PA-specific branch pathway were well represented in the library. Recombinant tea leucoanthocyanidin reductase (CsLAR) expressed in Escherichia coli was active with leucocyanidin as substrate to produce the 2R,3S-trans-flavan-ol (+)-catechin in vitro. Two genes encoding anthocyanidin reductase, CsANRl and CsANR2, were also expressed in E. coli, and the recombinant proteins exhibited similar kinetic properties. Both converted cyanidin to a mixture of (+)-epicatechin and (-)-catechin, although in different proportions, indicating that both enzymes possess epimerase activity. These epimers were unexpected based on the belief that tea PAs are made from (-)-epicatechin and (+)-catechin. Ectopic expression of CsANR2 or CsLAR led to the accumulation of low levels of PA precursors and their conjugates in Medicago truncatula hairy roots and anthocyanin-overproducing tobacco (Nicotiana tabacum), but levels of oligomeric PAs were very low. Surprisingly, the expression of CsLAR in tobacco overproducing anthocyanin led to the accumulation of higher levels of epicatechin and its glucoside than of catechin, again highlighting the potential importance of epimerization in flavan-3-ol biosynthesis. These data provide a resource for understanding tea PA biosynthesis and tools for the bioengineering of flavanols. [ABSTRACT FROM AUTHOR]

Desorption isotherm of fresh tea leaves was studied using static gravimetric method of saturated salt solutions at temperatures of 15, 20, 25 and 30ºC and water activities of 0.07 to 0.97. Data were fitted to five mathematical equations. Using the best-fit mathematical model, thermodynamic properties of fresh tea leaves including net isosteric heat of sorption, differential entropy were estimated. The applicability of enthalpy - entropy compensation theory for fresh tea leaves was also evaluated. Results showed that the modified Oswin model was best fitted with the experimental data. Thermodynamics properties like net isosteric heat of sorption and differential entropy were found to decrease exponentially with the increase in moisture content. Net isosteric heat of sorption and differential entropy increased exponentially with decreasing moisture content of fresh tea leaves. Isosteric heat of sorption of fresh tea leaves was very close to heat of vaporization of pure water when the moisture content of tea leaves exceeded 40% (d.b.). The enthalpy-entropy compensation theory could be successfully applied for the moisture desorption behavior of fresh tea leaf samples and it was enthalpy driven spontaneous process. [ABSTRACT FROM AUTHOR]

Abstract Levels of (-)-epicatechin in tea cultivars resistant to blister blight leaf disease were significantly higher than those in susceptible cultivars, while the reverse was true for (-)-epigallocatechin gallate, suggesting that epicatechin was involved in the resistance mechanism. The content of the methylxanthines, caffeine and theobromine, in the leaf increased in the initial translucent stage of the disease, probably as a defense response to fungal attack. Epicatechin and epigallocatechin levels were less than in healthy tissues at this stage, but increases in the corresponding gallate esters suggested that they were being converted into esters. Although epicatechin and epigallocatechin levels decreased from translucent to mature blister stages, the decrease was not significant. The decrease in levels of epicatechin, epigallocatechin, and their esters on infection and the formation of cyanidin and delphinidin on oxidative depolymerization of the blisters suggests that proanthocyanidins may play a role in the defense mechanism. The high resistance of a purple green leafed cultivar is attributed to the additional catechin source provided by the high levels of anthocyanins present. [ABSTRACT FROM AUTHOR]

The giant inguinal hernia has now become rare. Better hygienic conditions and better hernioplasty techniques, carried out with local anesthesia; usually encourage patients to undergo surgical treatment of the hernia soon after diagnosis. A case of giant inguinoscrotal hernia is being reported. Problems arise in management for both the patient and the surgeons because of the rarity of reported cases. [ABSTRACT FROM AUTHOR]