Tramp Ship Scheduling Problem with Berth Allocation Considerations and Time-dependent Constraints

This work presents a model for the Tramp Ship Scheduling problem including berth allocation considerations, motivated by a real case of a shipping company. The aim is to determine the travel schedule for each vessel considering multiple docking and multiple time windows at the berths. This work is innovative due to the consideration of both spatial and temporal attributes during the scheduling process. The resulting model is formulated as a mixed-integer linear programming problem, and a heuristic method to deal with multiple vessel schedules is also presented. Numerical experimentation is performed to highlight the benefits of the proposed approach and the applicability of the heuristic. Conclusions and recommendations for further research are provided.Comment: 16 pages, 3 figures, 5 tables, proceedings paper of Mexican International Conference on Artificial Intelligence (MICAI) 201

Pricing and hedging american options analytically: A perturbation method

This paper studies the critical stock price of American options with continuous dividend yield. We solve the integral equation and derive a new analytical formula in a series form for the critical stock price. American options can be priced and hedged analytically with the help of our critical-stock-price formula. Numerical tests show that our formula gives very accurate prices. With the error well controlled, our formula is now ready for traders to use in pricing and hedging the S&P 100 index options and for the Chicago Board Options Exchange to use in computing the VXO volatility index. © 2010 Wiley Periodicals, Inc.postprin

Protein sliding and hopping kinetics on DNA

Using Monte-Carlo simulations, we deconvolved the sliding and hopping kinetics of GFP-LacI proteins on elongated DNA from their experimentally observed seconds-long diffusion trajectories. Our simulations suggest the following results: (1) in each diffusion trajectory, a protein makes on average hundreds of alternating slides and hops with a mean sliding time of several tens of ms; (2) sliding dominates the root mean square displacement of fast diffusion trajectories, whereas hopping dominates slow ones; (3) flow and variations in salt concentration have limited effects on hopping kinetics, while in vivo DNA configuration is not expected to influence sliding kinetics; furthermore, (4) the rate of occurrence for hops longer than 200 nm agrees with experimental data for EcoRV proteins

Impact of Driving Cycles on Greenhouse Gas (GHG) Emissions, Global Warming Potential (GWP) and Fuel Economy for SI Car Real World Driving

The transport sector is one of the major contributors to greenhouse gas emissions. This study investigated three greenhouse gases emitted from road transport: CO2, N2O and CH4 emissions as a function of engine warm up and driving cycles. Five different urban driving cycles were developed and used including free flow driving and congested driving. An in-vehicle FTIR (Fourier Transform Inferred) emission measurement system was installed on a EURO2 emission compliant SI (Spark Ignition) car for emissions measurement at a rate of 0.5 HZ under real world urban driving conditions. This emission measurement system was calibrated on a standard CVS (Constant Volume Sampling) measurement system and showed excellent agreement on CO2 measurement with CVS results. The N2O and CH4 measurement was calibrated using calibration gas in lab. A MAX710 real time in-vehicle fuel consumption measurement system was installed in the test vehicle and real time fuel consumption was then obtained. The temperatures across the TWC (Three Way Catalyst) and engine out exhaust gas lambda were measured. The GHG (greenhouse gas) mass emissions and consequent GWP (Global Warming Potential) for different urban diving conditions were analyzed and presented. The results provided a better understanding of traffic related greenhouse gas emission profile in urban area and will contribute to the control of climate change

Unsupervised learning for cross-domain medical image synthesis using deformation invariant cycle consistency networks

Recently, the cycle-consistent generative adversarial networks (CycleGAN) has been widely used for synthesis of multi-domain medical images. The domain-specific nonlinear deformations captured by CycleGAN make the synthesized images difficult to be used for some applications, for example, generating pseudo-CT for PET-MR attenuation correction. This paper presents a deformation-invariant CycleGAN (DicycleGAN) method using deformable convolutional layers and new cycle-consistency losses. Its robustness dealing with data that suffer from domain-specific nonlinear deformations has been evaluated through comparison experiments performed on a multi-sequence brain MR dataset and a multi-modality abdominal dataset. Our method has displayed its ability to generate synthesized data that is aligned with the source while maintaining a proper quality of signal compared to CycleGAN-generated data. The proposed model also obtained comparable performance with CycleGAN when data from the source and target domains are alignable through simple affine transformations

Highly Stable RNA Capture by Dense Cationic Polymer Brushes for the Design of Cytocompatible, Serum-Stable SiRNA Delivery Vectors

The high density of polymer brushes confers to these coatings unique physicochemical properties, in particular for the regulation of biomolecular interaction and the design of highly selective coatings for biosensors and protein patterning. Here, we show that high density poly­(dimethylaminoethyl methacrylate) cationic polymer brushes enable the stable uptake of high levels of oligonucleotides. This is proposed to result from the high degree of crowding and associated increase in entropic driving force for the binding of polyelectrolytes such as nucleic acid molecules. We further demonstrate the ease with which such coatings allow the design of highly structured nanomaterials for siRNA delivery using block copolymer-brush-based nanoparticles that allow the protection of oligonucleotides by a protein-resistant outer block. In particular, these nanomaterials display a high serum stability and low cytotoxicity while retaining excellent knock down efficiencies. Polymer brush-based nanomaterials therefore appear particularly attractive for the rational design of a new generation of high performance theranostics and RNA delivery probes

Epigenetic programming by maternal nutrition: shaping future generations

Within the Western world’s aging and increasingly overweight population, we are seeing an increasing prevalence of adult-onset, lifestyle-related disease such as diabetes, hypertension and atherosclerosis. There is significant evidence that suboptimal nutrition in pregnancy can lead to an increased risk of these diseases developing in offspring, and that this increased risk can be heritable. Thus, poor in utero nutrition may be a major contributor to the current cycle of obesity. While the molecular basis of this phenomenon is unknown, available evidence suggests that it can be mediated by epigenetic changes to gene expression. Here, we discuss epigenetics as a mediator of disease risk in response to nutritional cues. The potential for maternal nutrition to heritably alter epigenetic states may have implications for population health and adaptive evolution

Kinetic barriers to SNAREpin assembly in the regulation of membrane docking/priming and fusion

Neurotransmission is achieved by soluble NSF attachment protein receptor (SNARE)-driven fusion of readily releasable vesicles that are docked and primed at the presynaptic plasma membrane. After neurotransmission, the readily releasable pool of vesicles must be refilled in less than 100 ms for subsequent release. Here we show that the initial association of SNARE complexes, SNAREpins, is far too slow to support this rapid refilling owing to an inherently high activation energy barrier. Our data suggest that acceleration of this process, i.e., lowering of the barrier, is physiologically necessary and can be achieved by molecular factors. Furthermore, under zero force, a low second energy barrier transiently traps SNAREpins in a half-zippered state similar to the partial assembly that engages calcium-sensitive regulatory machinery. This result suggests that the barrier must be actively raised in vivo to generate a sufficient pause in the zippering process for the regulators to set in place. We show that the heights of the activation energy barriers can be selectively changed by molecular factors. Thus, it is possible to modify, both in vitro and in vivo, the lifespan of each metastable state. This controllability provides a simple model in which vesicle docking/priming, an intrinsically slow process, can be substantially accelerated. It also explains how the machinery that regulates vesicle fusion can be set in place while SNAREpins are trapped in a half-zippered state