Bicriteria scheduling of a two-machine flowshop with sequence-dependent setup times

The official published version of the article can be found at the link below.A two-machine flowshop scheduling problem is addressed to minimize setups and makespan where each job is characterized by a pair of attributes that entail setups on each machine. The setup times are sequence-dependent on both machines. It is shown that these objectives conflict, so the Pareto optimization approach is considered. The scheduling problems considering either of these objectives are NP-hard , so exact optimization techniques are impractical for large-sized problems. We propose two multi-objective metaheurisctics based on genetic algorithms (MOGA) and simulated annealing (MOSA) to find approximations of Pareto-optimal sets. The performances of these approaches are compared with lower bounds for small problems. In larger problems, performance of the proposed algorithms are compared with each other. Experimentations revealed that both algorithms perform very similar on small problems. Moreover, it was observed that MOGA outperforms MOSA in terms of the quality of solutions on larger problems.Partial Funding from EPSRC under grant EP/D050863/1

Neural Differentiation of Whartonś Jelly Stem Cells in Three-Dimensional Chitosan Based Culture Environment

BACKGROUND AND OBJECTIVE: Wharton Jelly Stem Cells (WJSCs) can be a good option for differentiating and regeneration of nervous system damage. Three dimensional (3D) cell cultures by providing a body-like environment have more advantages than the two dimensional (2D) cell cultures. The aim of this study was to investigate the neural differentiation of these cells in a 3D chitosan based culture environment. METHODS: This experimental study was performed in 4 groups of 2&3D with and without differentiation media on WJSCs. First, to construct the hydrogel, hydroxyl ethyl cellulose was added to chitosan-beta-glycerophosphate solution (8.4: 0.8) (HEC: CH-β-GF). Human WJSCs after isolation by enzymatic method from wartons' jelly of born infant in Imam Khomeini hospital in Tehran and characterization with flow cytometry, were cultured 510 5 cell in each well of 24-well plate in a 2D and 3D environment using the hydrogel in neural differentiation media for 4 days. Then, the neural differentiation of WJSCs was evaluated by quantitative analysis of β-Tubulin III, Nestin and β-actin (internal control) genes expression by Real Time PCR (RT-PCR). FINDINGS: The results of RT-PCR showed that expression of β-Tubulin III and Nestin genes in WJSCs was significantly increased by the influence of the neural differentiation media in both 2D (more than 4 folds)and 3D (more than 2 folds) culture conditions (p <0.005). But the expression of β-Tubulin III and Nestin in 3D cell culture condition (more than 1.5 folds) was greater than that in the 2D cell culture condition under the influence of the neural differentiation media (p <0.01). CONCLUSION: The results showed that neural differentiation of WJSCs in a chitosan based 3D environment is higher than 2D

Evolution of Thick Walls in Curved Spacetimes

We generalize our previous thick shell formalism to incorporate any codimension-1 thick wall with a peculiar velocity and proper thickness bounded by arbitrary spacetimes. Within this new formulation we obtain the equation of motion of a spherically symmetric dust thick shell immersed in vacuum as well as in Friedmann-Robertson-Walker spacetimes.Comment: 8 pages, 1 figur

An Inhomogeneous Model Universe Behaving Homogeneously

We present a new model universe based on the junction of FRW to flat Lemaitre-Tolman-Bondi (LTB) solutions of Einstein equations along our past light cone, bringing structures within the FRW models. The model is assumed globally to be homogeneous, i.e. the cosmological principle is valid. Local inhomogeneities within the past light cone are modeled as a flat LTB, whereas those outside the light cone are assumed to be smoothed out and represented by a FRW model. The model is singularity free, always FRW far from the observer along the past light cone, gives way to a different luminosity distance relation as for the CDM/FRW models, a negative deceleration parameter near the observer, and correct linear and non-linear density contrast. As a whole, the model behaves like a FRW model on the past light cone with a special behavior of the scale factor, Hubble and deceleration parameter, mimicking dark energy.Comment: 23 pages, 19 figures, published version in GR

Lovelock gravity from entropic force

In this paper, we first generalize the formulation of entropic gravity to (n+1)-dimensional spacetime. Then, we propose an entropic origin for Gauss-Bonnet gravity and more general Lovelock gravity in arbitrary dimensions. As a result, we are able to derive Newton's law of gravitation as well as the corresponding Friedmann equations in these gravity theories. This procedure naturally leads to a derivation of the higher dimensional gravitational coupling constant of Friedmann/Einstein equation which is in complete agreement with the results obtained by comparing the weak field limit of Einstein equation with Poisson equation in higher dimensions. Our study shows that the approach presented here is powerful enough to derive the gravitational field equations in any gravity theory. PACS: 04.20.Cv, 04.50.-h, 04.70.Dy.Comment: 10 pages, new versio

Ecological study on fisheries important rivers and bays in the south part of the Caspian Sea 2nd phase: Gorgan Bay

In this study ichthyoplankton, phytoplankton, zooplankton, benthic and hydrochemistry parameters were studied. 9 out of 11 sampling stations were in the Gorgan Bay area and 2 of them were in the mouth of the Bay. Ichthyoplankton survey were carried out in 6 stations and the other surveys such as phytoplankton, etc were done in 11 stations in 2009. Gorgan Bay map and position of sampling sites are given at the end of material and methods section. Biomass and frequency of phytoplankton at different stations, months and seasons were calculated that are presented in Tables 1 to 3. Hydro-chemical parameters such as water temperature, air temperature, visibility, DO, BOD5, pH, Alkalinity (bicarbonate, carbonate and total), Hardness (calcium, magnesium), CL,EC, Salinity, N (nitrate, nitrite, NH_3), Phosphate were measured and results are shown Table 11. Biomass (mgr/m^3) and numbers (ind./m^3) of 47 genus of different phylum of phytoplanktons such as Cyanophyta, Chlorophyta, Pyrophyta, Chrysophyta and Euglenaphyta as well as different phylum of zooplanktons consist of Protozoa, Arthropoda, Rotifera and Cyliophora were estimated. Frequency of phytoplanktons (ind/m^3) was 131.2, 1.6, 65.3, 18.9 and 23.8 million respectively. Furthermore, their biomass was 308.4, 1.9, 1358.9, 295.1 and 124.7 mg/m^3, respectively. The maximum and minimum numbers were observed in Leptolingbaya belonged to Cyanophyta and Diatoms of Chrysophyta 84.3 and 0.025 million (ind/ m^3) respectively. The maximum and minimum biomass was observed in Gyrosigma (Chrysophyta) and Tetradron (Chloropyta), 12317.3 and 0.014 mg/m3 respectively. The average biomass of zooplankton was measured 531.74, 30.77, 225.07, and 96.26 mg/m^3 respectively and the total was attained 883.83 mg/m3 Table 5. The maximum and minimum biomass of all zooplanktons was estimated in November and July, 3446.23 and 6 mg/m^3 respectively. Furthermore, the maximum and minimum numbers of zooplanktons were found in September and July which were 48.4 and 0.002 millions respectively and the average number was 8.4 ind/m^3 Table 4. Also numbers and biomass (gr/m^2) of 11 families of benthos which inhabit Gorgan Bay such as Annelida, Mollusca and Arthropoda were investigated in separated stations and distinctive months. The maximum and minimum biomass of benthos was observed in January (42.91 gr/m^2) and March (0.6428 gr/m^2). The biomass was considerable in April, February, August and December (Tables: 4, 5 and 6)

A Review of One-Way and Two-Way Experiments to Test the Isotropy of the Speed of Light

As we approach the 125th anniversary of the Michelson-Morley experiment in 2012, we review experiments that test the isotropy of the speed of light. Previous measurements are categorized into one-way (single-trip) and two-way (round-trip averaged or over closed paths) approaches and the level of experimental verification that these experiments provide is discussed. The isotropy of the speed of light is one of the postulates of the Special Theory of Relativity (STR) and, consequently, this phenomenon has been subject to considerable experimental scrutiny. Here, we tabulate significant experiments performed since 1881 and attempt to indicate a direction for future investigation.Comment: Updated Fig. 7 and references; Revised sections 3.2 and 4. Accepted in the Indian Journal of Physics on March 30, 201

PTEN status is a crucial determinant of the functional outcome of combined MEK and mTOR inhibition in cancer

Combined MAPK/PI3K pathway inhibition represents an attractive, albeit toxic, therapeutic strategy in oncology. Since PTEN lies at the intersection of these two pathways, we investigated whether PTEN status determines the functional response to combined pathway inhibition. PTEN (gene, mRNA, and protein) status was extensively characterized in a panel of cancer cell lines and combined MEK/mTOR inhibition displayed highly synergistic pharmacologic interactions almost exclusively in PTEN-loss models. Genetic manipulation of PTEN status confirmed a mechanistic role for PTEN in determining the functional outcome of combined pathway blockade. Proteomic analysis showed greater phosphoproteomic profile modification(s) in response to combined MEK/mTOR inhibition in PTEN- loss contexts and identified JAK1/STAT3 activation as a potential mediator of synergistic interactions. Overall, our results show that PTEN-loss is a crucial determinant of synergistic interactions between MAPK and PI3K pathway inhibitors, potentially exploitable for the selection of cancer patients at the highest chance of benefit from combined therapeutic strategies

Neurofeedback Using Real-Time Near-Infrared Spectroscopy Enhances Motor Imagery Related Cortical Activation

Accumulating evidence indicates that motor imagery and motor execution share common neural networks. Accordingly, mental practices in the form of motor imagery have been implemented in rehabilitation regimes of stroke patients with favorable results. Because direct monitoring of motor imagery is difficult, feedback of cortical activities related to motor imagery (neurofeedback) could help to enhance efficacy of mental practice with motor imagery. To determine the feasibility and efficacy of a real-time neurofeedback system mediated by near-infrared spectroscopy (NIRS), two separate experiments were performed. Experiment 1 was used in five subjects to evaluate whether real-time cortical oxygenated hemoglobin signal feedback during a motor execution task correlated with reference hemoglobin signals computed off-line. Results demonstrated that the NIRS-mediated neurofeedback system reliably detected oxygenated hemoglobin signal changes in real-time. In Experiment 2, 21 subjects performed motor imagery of finger movements with feedback from relevant cortical signals and irrelevant sham signals. Real neurofeedback induced significantly greater activation of the contralateral premotor cortex and greater self-assessment scores for kinesthetic motor imagery compared with sham feedback. These findings suggested the feasibility and potential effectiveness of a NIRS-mediated real-time neurofeedback system on performance of kinesthetic motor imagery. However, these results warrant further clinical trials to determine whether this system could enhance the effects of mental practice in stroke patients