Use Of High Number Research Articles

Genetic evidence of successful establishment of the Nile perch (Lates spp. L.) in East African lakes and implications for management

Nile perch establishment in novel ranges in East Africa is one of the most successful freshwater invasion stories in the recent history. It became ecologically dominant and well established in several lakes in the Lake Victoria Region in a period of less than 5 decades. Genetic diversity of both introduced and native populations were assessed and patterns compared in order to establish the genetic consequences of their introductions. Genetic variation was surveyed at both the mitochondrial control region (CR) and at nine microsatellite loci. A total of 527 Nile perch fish were sampled from 5 East African lakes: native source populations were examined from lakes Albert and Turkana while introduced populations were sampled from lakes Kyoga, Nabugabo and Victoria. Both types of markers revealed higher average genetic diversity for invasive species (HE = 0.70, h = 0.81) than for native source populations (HE = 0.66, h = 0.69). Both populations scored relatively higher than the average for freshwater fishes (HE = 0.62). Both native and introduced populations had 2 underlying genetic groupings in similar proportions as revealed by the STRUCTURE program. The high genetic diversity was most probably a consequence of higher numbers of propagules than outlined by official records of introductions. Use of high number of individuals at stocking is probably the reason for apparently minimized ‘founder effects’ of Nile perch in the introduced ranges. The two underling populations revealed through genetic analysis may be representatives of the two subspecies of Nile perch previously reported in other studies. Implications to the management of this fishery in the East African region is that with the relatively high genetic diversity, the species could be sustainably exploited if it were effectively managed. In addition, further studies of the life histories and other attributes of the two genetic groupings of Nile perch in the region are recommended, as they may require different management plans.

Assessing manual lifting tasks based on segment angle interpolations

This study investigates the effects of the number of interpolation points on the prediction accuracy of segment angle trajectory during lifting. Ten participants performed various lifting tasks while a motion tracking system recorded their movements. Two-point through ten-point equal time-spaced segment angles extracted from major segment trajectory data captured by the motion tracking system were used to re-generate the whole body lifting motion by using polynomial and cubic spline interpolation methods. The root mean square error (RMSE) between the reference (motion tracking system) and the estimated (interpolation method) segment angle trajectories were calculated to quantify the prediction accuracy. The results showed that the cubic spline interpolation will yield a smaller RMSE value than one based on the polynomial interpolation. While increasing the number of interpolation points can reduce the RMSE of the estimated segment angle trajectories, there was a diminishing advantage in continuing to add interpolation points. A sensitivity analysis suggests that if the estimation of the segment angles at each interpolation point deviates considerably from the real value, and cannot be controlled at a low level (<10 (), the use of higher number of interpolation points will not improve the estimation accuracy.

Analysis of the performance of the ship steam boiler using simulation

The aim of this paper is to demonstrate the successful application of system dynamics simulation modelling at investigating performance dynamics of the ship steam boiler. Ship steam boiler is a complex non-linear system which needs to be systematically investigated as a unit consisting of a number of subsystems and elements, which are linked by cause-effect feedback loops, both within the system and with the relevant surrounding. In this paper the authors will present the efficient application of scientific methods for the research of complex dynamic systems called qualitative and quantitative simulation system dynamics methodology, which will allow for production and use of higher number and kinds of simulation models of the observed elements, and finally allow for the continuous computer simulation, which will contribute to acquisition of new information about the non-linear character of performance dynamics of ship steam boilers in the process of designing and education. Ship steam boiler will be presented in POWERSIM simulation language in mental-verbal, structural, and mathematical computer models.

A model of isolated autologously hemoperfused porcine slaughterhouse lungs

Models of isolated and perfused lungs study pathophysiological phenomena of the airways, but are limited by restricted resemblance to the human situation, non-physiological perfusates or the need for the use of high numbers of laboratory animals. The present model was established to address these difficulties. Aim of the current study was the establishment of an animal model that uses slaughterhouse animals and closely resembles physiological conditions found in humans. We used a model of hemoperfused isolated porcine slaughterhouse lungs using autologous blood, metabolically controlled via a dialysis system. Over a period of 135 minutes positive inspiratory pressure, pulmonary arterial pressure, pulmonary vein oxygen partial pressure and lung weight were assessed. Stable organ function was maintained over 135 minutes with an amount of 2,500-3,000 ml perfusate without fall in pulmonary arterial pressure. During the time the positive inspiratory pressure and lung weight increased, while pulmonary vein oxygen partial pressure decreased. The present model of isolated hemoperfused slaughterhouse lungs displays a useful new and economic approach to evaluate pulmonary function and toxicity of different substances on an organ level. As a major economic advantage in comparison to models using laboratory animals, the current model might be run using blood and organs obtained from slaughterhouse animals.

Study of edge effect and multi-curvature in laser bending of AISI 304 stainless steel

Abstract Laser bending is a weakly coupled thermo-mechanical process, where thermal energy is utilized to carry out the bending process. This offers an excellent tool in automotive, shipbuilding and aerospace applications. This study deals with the edge effect in laser bending of AISI 304 stainless steel, which was carried out using a 10 kW continuous wave CO2 laser. The study of the variations in bending angle, along the longitudinal direction of laser scanning path (edge effect) through physical optimization, has clearly demonstrated that the edge effect depends on multiple process parameters. It has also been found that the laser bending sometime can render a multi-curvature on a single laser scan path. The so called multi-curvature phenomenon has been found to be very much dependent on the laser scanning speed and the extent of this effect can be minimized with the use of higher number of passes.

Relationship between possession of electric appliances and electricity for lighting and others in Japanese households

A questionnaire survey on the possession of electric appliances and on its influence upon the energy consumption in Japanese households was conducted in 1996. It was found that the increase in the consumption of residential electricity was due to the use of higher number of electric appliances. This reflects the higher economic status of the householders and their lifestyle. The relationship between electric consumption for lighting and others and the influencing factor is evaluated by using the multivariate analysis. The results of this study are expected to provide fundamental information in order to enhance residents’ awareness on the importance of energy conservation. It is also expected that the results will be helpful for Asian developing countries.

住宅における電気機器の所有状況と照明・動力他用電力消費量に関する調査

A questionnaire survey on the possession of electric appliances and its influence on the energy consumption in household were conducted in 1996. It was found that the increase in the consumption of residential electricity was due to the use of higher number of electric appliances. This reflects the higher economic status of the household and their life style. The relationship between electric consumption for lighting and others and the influencing factor is evaluated by using the multi-variate analysis. The results of this study are expected to provide fundamental information in order to enhance residents' awareness of the importance of energy conservation.

Influência da área da parcela e do número de repetições na precisão de experimentos com arbóreas

Os experimentos de campo com plantas perenes arbóreas ocupam grandes áreas, em razão do porte das plantas que exigem largos espaçamentos. É freqüente usarem-se parcelas grandes, em detrimento do número de repetições, para diminuir a área experimental, a mão-de-obra e o conseqüente custo da pesquisa. Essa prática, contudo, traz prejuízos à precisão das estimativas dos parâmetros e à aplicação eficiente de testes estatísticos. Este trabalho teve o objetivo de mostrar que o uso de parcelas pequenas favorece o aumento do número de repetições, diminui a área dos experimentos e aumenta a sua precisão. O método utilizado associa o tamanho da unidade experimental ao número de repetições, pela minimização da variância da média de cada tratamento, permitindo maior número de repetições, para aumentar a precisão dos testes, obter maior uniformidade no experimento e melhorar a qualidade das pesquisas. Parcelas pequenas favorecem o aumento do número de repetições, permitem obter melhores estimativas do erro experimental, dos efeitos de tratamentos e dos parâmetros, dando mais eficiência aos testes estatísticos aplicados aos dados. Houve diminuição do número de plantas necessárias ao experimento e redução da área experimental em cerca de 18%.

The isolated perfused liver: a new model using autologous blood and porcine slaughterhouse organs

Introduction: Current models of isolated and perfused livers are limited by nonphysiologic perfusates or the need for the use of high numbers of laboratory animals. The present study was performed in order to rectify these difficulties. Methods: To establish a new isolated perfused liver model, a perfusion circuit was developed using normothermic, autologous hemoperfusion and organs obtained from a slaughterhouse. Results: Stable organ function was maintained over 220 min. The organs displayed physiologic values for measured variables, including oxygen consumption which varied from 5.2±1.5 ml/min at 40 min to 5.2±2.4 ml/min at 220 min, and bile production (0.15–0.31 ml/min, respectively). Discussion: The present studies demonstrate a new approach for experimental liver perfusion by combining the optimal perfusion medium of autologous blood and slaughterhouse organs as source material.

Exploring the diversity of multimedia systems

We evaluate the validity of the fundamental assumption behind application-specific programmable processors: that applications differ from each other in key parameters which are exploitable, such as the available instruction-level parallelism (ILP), demand on various hardware resources, and the desired mix of function units. Following the tradition of the CAD community, we develop an accurate chip area estimate and a set of aggressive hardware optimization algorithms. We follow the tradition of the architecture community by using comprehensive real-life benchmarks and production quality tools. This combination enables us to build a unique framework for system-level synthesis and to gain valuable insights about design and use of application-specific programmable processors for modern applications. We explore the application-specific programmable processor (ASSP) design space to understand the relationship between performance and area. The architecture model we used is the Hewlett Packard PA-RISC with single level caches. The system, including all memory and bus latencies, is simulated and no other specialized ALU or memory structures are being used. The experimental results reveal a number of important characteristics of the ASSP design space. For example, we found that in most cases a single programmable architecture performs similarly to a set of architectures that are tuned to individual application. A notable exception is highly cost sensitive designs, which we observe need a small number of specialized architectures that require smaller areas. Also, it is clear that there is enough parallelism in the typical media and communication applications to justify use of high number of function units. We found that the framework introduced in this paper can be very valuable in making early design decisions such as area and architectural configuration tradeoff, cache and issue width tradeoff under area constraint, and the number of branch units and issue width.

TEMPORARY NEUROLOGICAL IMPROVEMENT AFTER BIOARTIFICIAL LIVER TREATMENT FOR ACUTE ON CHRONIC LIVER FAILURE

Purpose of the study: The use of bioartificial liver (BAL) has been reported to be an optimal temporary support until liver transplantation for patients affected by fulminant hepatic failure. At present data on cases of acute exacerbation of chronic liver disease are less encouraging since no clear neurological improvement have been reported yet. The use of higher number of hepatocytes and of hollow-fiber with greater porosity might help to improve results in these cases. Methods used: A 57 year old man with an acute exacerbation of chronic liver disease related to HBV infection, grade 3 potto-systemic encephalopathy, insulin dependent diabetes and renal failure was admitted to the surgical ICU in hepatic coma [Glasgow Coma Scale (GCS)=6]. EEG evaluation at admission revealed a diffuse metabolic neurological distress. BAL procedure, using cryopreserved porcine hepatocytes, was performed every 48 hours for 3 times. Briefly, 1,5±1010 viable porcine hepatocytes and 10g hydrated collagen coated dextran microcarriers were loaded into the extrafiber space of a hollow-fiber bioreactor (0,6μm porosity). Patient underwent plasmapheresis and plasma recirculated through an activated cellulose-charcoal column, an oxygenator, a heater and finally through the bioreactor loaded with porcine hepatocytes. Treatments lasted 6 hours. Results: patient tolerated the procedure very well, cardiovascular and pulmonary functions were not altered. At the end of the last treatment the patient recovered from coma conditions. Glasgow Coma Scale improved to 11. Amelioration of neurological status was confirmed by EEG evaluation that revealed a improvement in the basic neurological activity with reduction of Δ waves. These results suggest that repeated BAL procedures using higher number of hepatocytes and a large porosity hollow fiber has been well tolerated and resulted in temporary neurological improvement in a patient with acute on chronic liver failure.

MULTIPLE DONOR ALLOTRANSPLANTATION

Currently it is not feasible to isolate sufficient numbers of islets from a single pancreas for clinical transplantation. We examined whether small numbers of islets obtained from multiple donors could be used for transplantation. Islets were isolated from four inbred strains of mice (DBA/2, DBA/1, C3H, and A.SW) by a stationary collagenase digestion and Ficoll separation and transplanted into the renal subcapsular space of streptozotocin-induced diabetic B6AF1 mice. At least 200 handpicked islets were required to produce normoglycemia in syngeneic and allogeneic diabetic recipient mice. None of the mice given 50 islets became normoglycemic within 2 weeks postgrafting. When various numbers of purified islets from a single donor were transplanted, the survival was significantly better for 200-islet allografts than for 800-islet and 400-islet allografts. When a 200-islet composite graft was prepared from four donors (50 fresh handpicked islets from each donor), the survival of the composite graft as measured by sustained normoglycemia in nonimmunosuppressed recipients was dramatic, with 17 of 18 recipients maintaining normoglycemia indefinitely (greater than 200 days). Similarly, when islets isolated from four donors and cultured for various periods were mixed and transplanted (200 islets/recipient) all recipient mice (n = 8) enjoyed indefinite graft survival. Use of higher numbers of purified islets or crude islets in a composite multiple-donor islet allograft was less effective in achieving indefinite graft survival. Thus, transplantation of a composite graft made up with subtherapeutic numbers of islets from multiple histoincompatible donors to provide adequate therapeutic numbers is a practical solution to the lack of islet availability. In addition, composite islet grafts appear to possess immunological advantages, with significantly prolonged survival over that produced by single-donor islet grafts.

Microsatellite marker-based genetic variability in Spanish rice cultivars and landraces

The genetic relationships among japonica rice cultivars and landraces were studied. Most of them are of Spanish origin, and were developed and cultivated for varying time periods over more than a century. To uncover genetic diversity within each cultivar, we analysed 30 plants per cultivar or accession using 10 fluorescently labelled primer pairs for SSR markers. Six cultivars were included in the study, with accessions from four different regions of Spain of the traditional cultivar Bomba. A total of 37 alleles were detected with a mean of 3.7 alleles per locus. Polymorphism information content (PIC) ranged from 0 to 0.78 with an average of 0.51 per locus. Genetic diversity for cvs. Albufera, Bahia, Taipei 309 and Jsendra ranged between 0.008 and 0.062. Cultivar Bomba accessions displayed higher number of alleles and genetic diversity, with Tarragona the lowest (0.08) and Valencia the highest (0.16) genetic diversity. Although infrequent, some heterozygous individuals were detected in cvs. Bomba, Bahia and Taipei 309. Cluster analysis enabled to categorize four accessions of cv. Bomba and cv. Albufera in one group and cvs. Bahia, Taipei 309, Jsendra and Senia in a second group supporting previously known relationships among varieties. These results show the utility of SSR markers for characterization of rice cultivars. In addition, the use of high number of individuals per cultivar, enabled to evaluate both inter- and intra-varietal genetic diversity. Therefore, this investigation should be useful in rice breeding programmes for genotype identification and for the evaluation of germplasm purity.