Development of growth rate, body lipid, moisture, and energy models for white sturgeon (Acipenser transmontanus) fed at various feeding rates.

The objectives were to develop and evaluate: 1) growth rate models, 2) body lipid, moisture, and energy models for white sturgeon fed at various feeding rates (FR; % body weight [BW] per day) and then evaluate responses at proportions of optimum feeding rate (OFR) across increasing BW (g). For objective 1, 19 datasets from the literature containing initial BW, FR and specific growth rate (SGR; % BW increase per day) were used. For objective 2, 12 datasets from the literature (11 from objective 1) containing SGR, FR, final BW, body lipid (%), protein (%), ash (%), moisture (%), and energy (kJ/g) were used. The average rearing temperatures was 19.2 ± 1.5 °C (mean ± SD). The average nutrient compositions and gross energy of the diets were 45.7 ± 4.3% protein, 14.8 ± 3.2% lipid, and 20.4 ± 1.3 kJ/g, respectively. The logistic model was used for objectives 1 and 2 to develop a statistical relationship between SGR and FR, then an iterative technique was used to estimate OFR for each dataset. For objective 2, the statistical relationship between body lipid, energy, and moisture and FR was established. Using the OFR estimate, SGR, body lipid, energy and moisture were computed at various FR as a proportion of OFR. Finally, a nonparametric fitting procedure was used to establish relationships between SGR, body lipid, energy and moisture (responses) compared with BW (predictor) at various proportions of OFR. This allows visualization of the effect of under- or over-feeding on the various responses. When examining the differences between OFR at 100% and various proportions of OFR, SGR differences decrease and moisture differences increase as BW increases. Lipid and energy differences decrease as BW increases. To our knowledge, these are the first description of changes in nutrient compositions when white sturgeon are fed at various FR. Because physiological and behavioral properties that are unique to sturgeon, results from this study are specific to sturgeon under the conditions of this study and cannot be compared directly with salmonids even if some of the results are similar. This research provides insight to designing future nutritional studies in sturgeon

On the Dynamic Resources Availability in Grids

This paper has been submitted to the Grid'2007 conference.Currently deployed grids gather together thousands of computational and storage resources for the benefit of a large community of scientists. However, the large scale, the wide geographical spread, and at times the decision of the rightful resource owners to commit the capacity elsewhere, raises serious resource availability issues. Little is known about the characteristics of the grid resource availability, and of the impact of resource unavailability on the performance of grids. In this work, we make first steps in addressing this twofold lack of information. First, we analyze a long-term availability trace and assess the resource availability characteristics of Grid'5000, an experimental grid environment of over 2,500 processors. Based on the results of the analysis, we further propose a model for grid resource availability. Our analysis and modeling results show that grid computational resources become unavailable at a high rate, negatively affecting the ability of grids to execute long jobs. Second, through trace-based simulation, we show evidence that resource availability can have a severe impact on the performance of the grid systems. The results of this step show evidence that the performance of a grid system can rise when availability is taken into consideration, and that human administration of availability change information results in 10-15 times more job failures than for an automated monitoring solution, even for a lowly utilized system

Determination of ghrelin immunoreactivity in the rat stomach after fasting and refeeding

Ghrelin is a recently discovered hormone secreted by cells of the stomach. The aim of this study was to investigate fasting and refeeding induced alterations on ghrelin immunolabelling of cells of the stomach. Thirty-six adult mate Wistar rats were used in this study. Rats were divided into six groups. Group I: control group; Group II: rats fasted for 7 days; Group III: rats fed for 1 day after 7 days of fasting; Group IV: rats fed for 3 days after 7 days of fasting; Group V: rats fed for 5 days after 7 days of fasting; Group VI: rats fed for 7 days after 7 days of fasting. At the end of the experiment, rats were sacrificed and stomach tissues were processed for imunohistochemistry to localize ghrelin. Ghrelin-immunopositive cells were detected only in the mucosal lining of the stomach. After fasting for 7 days, the number of ghrelin-immunopositive cells increased significantly compared to the control rats. Following refeeding, the number of ghrelin-immunoreactive cells was reduced to a level comparable to the controls. Therefore, fasting and refeeding after fasting were observed to result in changes in ghrelin immunoreactivity in the cells of the stomach. We conclude that ghrelin is highly expressed in the stomach and that fasting increases the expression of ghrelin in the stomach, but this expression decreases after refeeding. Our results indicate that regutation of ghrelin is a process probably involved in the long-term control of nutritional states. (c) 2007 Elsevier GmbH. All rights reserved

On the Benefit of Processor Co-Allocation in Multicluster Grid Systems

In multicluster grid systems, parallel applications may benefit from processor co-allocation, that is, the simultaneous allocation of processors in multiple clusters. Although co-allocation allows the allocation of more processors than available in a single cluster, it may severely increase the execution time of applications due to the relatively slow widearea communication. The aim of this paper is to investigate the benefit of co-allocation in multicluster grid systems, despite this drawback. To this end, we have conducted experiments in a real multicluster grid environment, as well as in a simulated environment, and we evaluate the performance of co-allocation for various applications that range from computation-intensive to communication-intensive and for various system load settings. In addition, we compare the performance of scheduling policies that are specifically designed for co-allocation. We demonstrate that considering latency in the resource selection phase improves the performance of co-allocation, especially for communicationintensive parallel applications

Investigation of the Salt Concentration Dependence of Water-Gated Field Effect Transistors (WG-FET) Using 16-nm-Thick Single Crystalline Si Film

This paper presents the effect of NaCl concentration on the operation of a water-gated field effect transistor (WG-FET) that uses 16-nm-thick single crystalline silicon (Si) film. In WG-FET, electrical double layer (EDL) formed at the water/silicon interface behaves as gate dielectric and this fluidic interface makes WG-FET a suitable device for sensing applications. Characteristics of EDL and the threshold voltage of WG-FET depend on the molarity of solution. Increasing the molarity of NaCl solution from 0.5 to 65 mM changes the threshold voltage from 360 to 465 mV. Accordingly, drain current of the WG-FET device changes with NaCl concentration

Displacement Sensor with Inherent Read-Out Circuit Using Water-Gated Field Effect Transistor (WG-FET)

This paper presents, for the first time, a displacement sensor with inherent read-out circuit using an inverter built with WG-FET that has 16-nm-thick single crystalline silicon film. In WG-FET, electrical double layer (EDL) capacitances are formed at water/silicon and water/top gate interfaces. These two capacitances and the resistance of the de-ionized (DI) water droplet build a first order RC network. Propagation delay of an inverter built with WG-FET depends on this RC constant. When the distance between top gate and silicon film changes, EDL capacitances remain the same, but resistance of the DI-water droplet changes. Accordingly, propagation delay of the inverter changes linearly with this distance. Increasing the distance from 400 µm to 1200 µm changes low-to-high propagation delay tplh of the inverter from 1.08 ms to 1.36 ms and high-to-low propagation delay tphl from 0.48 ms to 0.56 ms, which yields sensitivities of 0.35 µs/µm and 0.1 µs/µm, respectively

On the Dynamic Resources Availability in Grids

This paper has been submitted to the Grid'2007 conference.Currently deployed grids gather together thousands of computational and storage resources for the benefit of a large community of scientists. However, the large scale, the wide geographical spread, and at times the decision of the rightful resource owners to commit the capacity elsewhere, raises serious resource availability issues. Little is known about the characteristics of the grid resource availability, and of the impact of resource unavailability on the performance of grids. In this work, we make first steps in addressing this twofold lack of information. First, we analyze a long-term availability trace and assess the resource availability characteristics of Grid'5000, an experimental grid environment of over 2,500 processors. Based on the results of the analysis, we further propose a model for grid resource availability. Our analysis and modeling results show that grid computational resources become unavailable at a high rate, negatively affecting the ability of grids to execute long jobs. Second, through trace-based simulation, we show evidence that resource availability can have a severe impact on the performance of the grid systems. The results of this step show evidence that the performance of a grid system can rise when availability is taken into consideration, and that human administration of availability change information results in 10-15 times more job failures than for an automated monitoring solution, even for a lowly utilized system

The performance of bags-of-tasks in large-scale distributed systems

Ever more scientists are employing large-scale distributed systems such as grids for their computational work, instead of tightly coupled high-performance computing systems. However, while these distributed systems are more cost-effective, their heterogeneity in terms of hardware, software, and systems administration, and the lack of accurate resource information leads to inefficient scheduling. In addition, and in contrast to the workloads of tightly coupled high-performance computing systems, a large part of the workloads submitted to these distributed systems consists of large sets (bags) of sequential tasks. Therefore, a realistic performance analysis of scheduling bags-of-tasks in large-scale distributed systems is important. Towards this end, we introduce in this paper a realistic workload model for bags-of-tasks, and we explore through trace-based simulations the design space of scheduling bags-of-tasks. Finally, we identify three new scheduling policies that use only inaccurate information when scheduling, and we compare them against known classes of proposed scheduling policies