Inbound container storage price competition between the container terminal and a remote container yard

With the rapid development of global ocean transportation, storage space in container terminals is becoming a scarce resource. Hence, the terminal yard only performs as a temporary storage facility for inbound cargos. A storage charge is levied for inbound cargos that stay longer than a free storage time (called free-time-limit). After the free-time-limit, customers may move cargos from the terminal yard to a remote container yard where the storage price is lower than that in the terminal. This paper proposes inbound container storage pricing game models between the container terminal and a remote container yard. Two cases are considered: (1) the inbound container’s dwell time is random and follows a probability distribution function; (2) the inbound container’s dwell time is sensitive to the storage prices. The primary objective of this paper is to analyze the storage pricing behavior and competition outcomes of the container terminal and the remote container yard. A number of insights and analysis are provided.     

An analytical model for a short-term advantage for sex

An analytical treatment is given for a model of Maynard Smith in which a short-term advantage for sex and recombination is provided by the mechanism of sib-competition. Suppose the next generation is formed by the winners of a large number of contests. Suppose a number of parents each contribute M offspring to a given contest, but the offspring of an asexual parent are identical whereas those of a sexual parent are distributed with some variance. If M is large there is a high probability that a sexual offspring will have a high enough fitness to win the contest. Calculations show that values of M around 3 and 4 are generally enough for sexual behaviour to overcome its two-fold disadvantage.     

Strategies for improving a long-established terminal’s performance: a simulation study of a Turkish container terminal

Due to a long-lasting increase in global trade, only interrupted by the late-2000s economic crisis, container traffic has grown dramatically. As a result, new terminals have opened and existing terminals face much higher container handling than before. In order to meet these challenges, one of the biggest container terminals in Turkey has begun to reconsider its terminal operations and to achieve improvements of its overall logistics performance. Because the factors impacting the terminal’s performance are highly interrelated, a simulation model was developed to analyze the terminal operations, to identify potential bottleneck resources and to highlight directions for the future development of the configuration and the operational control system. For a long-established terminal like the one considered in this study the options for improving the overall performance are limited by the geographical dimensions and by the existing terminal equipment. By use of the simulation model the terminal operations are evaluated under different workload scenarios and alternative configurations are tested in order to support strategic decisions on the terminal’s development.     

Myoglobin as a model system for designing heme protein based blood substitutes

The ligand binding properties and resistances to denaturation of >300 different site-directed mutants of sperm whale, pig, and human myoglobin have been examined over the past 15 years. This library of recombinant proteins has been used to derive chemical mechanisms for ligand binding and to examine the factors governing holo- and apoglobin stability. We have also examined the effects of mutagenesis on the dioxygenation of NO by MbO(2) to form NO(3)(-) and metMb. This reaction rapidly detoxifies NO and is a key physiological function of both myoglobins and hemoglobins. The mechanisms derived for O(2) binding and NO dioxygenation have been used to design safer, more efficient, and more stable heme protein-prototypes for use as O(2) delivery pharmaceuticals in transfusion therapy (i.e. blood substitutes). An interactive database is being developed (http://olsonnt1.bioc.rice.edu/web/myoglobinhome.asp) to allow rapid access to the ligand binding parameters, stability properties, and crystal structures of the entire set of recombinant myoglobins. The long-range goal is to use this library for developing general protein engineering principles and for designing individual heme proteins for specific pharmacological and industrial uses.     

An evolutionary analytical model of a complementary circular code

The subset X0=[AAC,AAT,ACC,ATC,ATT,CAG,CTC,CTG, GAA,GAC,GAG,GAT,GCC,GGC,GGT,GTA,GTC,GTT,TAC,TTC] of 20 trinucleotides has a preferential occurrence in the frame 0 (reading frame established by the ATG start trinucleotide) of protein (coding) genes of both prokaryotes and eukaryotes. This subset X0 is a complementary maximal circular code with two permutated maximal circular codes X1 and X2 in the frames 1 and 2 respectively (frame 0 shifted by one and two nucleotides respectively in the 5'-3' direction). X0 is called a C3 code (Arquès and Michel, 1997, J. Biosyst 44, 107-134). A quantitative study of these three subsets X0, X1 and X2 in the three frames 0, 1 and 2 of eukaryotic protein genes shows that their occurrence frequencies are constant functions of the trinucleotide positions in the sequences. The frequencies of X0, X1 and X2 in the frame 0 of eukaryotic protein genes are 48.5%, 29% and 22.5% respectively. These properties are not observed in the 5' and 3' regions of eukaryotes where X0, X1 and X2 occur with variable frequencies around the random value (1/3). Several frequency asymmetries unexpectedly observed, e.g. the frequency difference between X1 and X2 in the frame 0, are related to a new property of the C3 code X0 involving substitutions. An evolutionary analytical model at three parameters (p, q, t) based on an independent mixing of the 20 codons (trinucleotides in the frame 0) of X0 with equiprobability (1/20) followed by t approximately 4 substitutions per codon according to the proportions p approximately 0.1, q approximately 0.1 and r = 1 - p - q approximately 0.8 in the three codon sites respectively, retrieves the frequencies of X0, X1 and X2 observed in the three frames of protein genes and explains these asymmetries. The complex behaviour of these analytical curves is totally unexpected and a priori difficult to imagine. Finally, the evolutionary analytical method developed could be applied to the phylogenetic tree reconstruction and the DNA sequence alignment.     

An analytical model for determining two-dimensional receptor-ligand kinetics

Cell-cell adhesive interactions play a pivotal role in major pathophysiological vascular processes, such as inflammation, infection, thrombosis, and cancer metastasis, and are regulated by hemodynamic forces generated by blood flow. Cell adhesion is mediated by the binding of receptors to ligands, which are both anchored on two-dimensional (2-D) membranes of apposing cells. Biophysical assays have been developed to determine the unstressed (no-force) 2-D affinity but fail to disclose its dependence on force. Here we develop an analytical model to estimate the 2-D kinetics of diverse receptor-ligand pairs as a function of force, including antibody-antigen, vascular selectin-ligand, and bacterial adhesin-ligand interactions. The model can account for multiple bond interactions necessary to mediate adhesion and resist detachment amid high hemodynamic forces. Using this model, we provide a generalized biophysical interpretation of the counterintuitive force-induced stabilization of cell rolling observed by a select subset of receptor-ligand pairs with specific intrinsic kinetic properties. This study enables us to understand how single-molecule and multibond biophysics modulate the macroscopic cell behavior in diverse pathophysiological processes.     

Kinetic model for designing a cancer therapy

A kinetic model has been developed to study cancer growth. Cancer growth has been considered as interaction between various independent but interacting compartments. The model considers cell growth and metastasis resulting in the formation of new tumor masses. Using certain representative parameter values, cell growth has been modeled in the absence and the presence of various cancer therapies. Based on this analysis, the critical parameters involved in cancer development have been identified. This model may thus be useful in studying and designing a cancer therapy using the data obtained from specific in vitro experiments.     

An analytical model of joint contact

The stress distribution in the region of contact between a layered elastic sphere and a layered elastic cavity is determined using an analytical model to stimulate contact of articulating joints. The purpose is to use the solution to analyze the effects of cartilage thickness and stiffness, bone stiffness and joint curvature on the resulting stress field, and investigate the possibility of cracking of the material due to tensile and shear stresses. Vertical cracking of cartilage as well as horizontal splitting at the cartilage-calcified cartilage interface has been observed in osteoarthritic joints. The current results indicate that for a given system (material properties mu and nu constant), the stress distribution is a function of the ratio of contact radius to layer thickness (a/h), and while tensile stresses are seen to occur only when a/h is small, tensile strain is observed for all a/h values. Significant shear stresses are observed at the cartilage-bone interface. Softening of cartilage results in an increase in a/h, and a decrease in maximum normal stress. Cartilage thinning increases a/h and the maximum contact stress, while thickening has the opposite effect. A reduction in the indenting radius reduces a/h and increases the maximum normal stress. Bone softening is seen to have negligible effect on the resulting contact parameters and stress distribution.     

An analytical model of memristors in plants

The memristor, a resistor with memory, was postulated by Chua in 1971 and the first solid-state memristor was built in 2008. Recently, we found memristors in vivo in plants. Here we propose a simple analytical model of 2 types of memristors that can be found within plants. The electrostimulation of plants by bipolar periodic waves induces electrical responses in the Aloe vera and Mimosa pudica with fingerprints of memristors. Memristive properties of the Aloe vera and Mimosa pudica are linked to the properties of voltage gated K⁺ ion channels. The potassium channel blocker TEACl transform plant memristors to conventional resistors. The analytical model of a memristor with a capacitor connected in parallel exhibits different characteristic behavior at low and high frequency of applied voltage, which is the same as experimental data obtained by cyclic voltammetry in vivo.     

An analytical model for random pseudonym change scheme in VANETs

The emerging Vehicular Ad hoc NETworks (VANETs) can improve safety, efficiency and convenience in transportation. In spite of the expected benefits, VANETs also introduce some location privacy risk by periodically broadcasting vehicular information. Pseudonym change is commonly accepted as one approach to protect location privacy in VANETs, but the effectiveness of most pseudonym change schemes has never been investigated theoretically. In this paper, focusing on the Random Pseudonym Change (RPC) scheme, we propose an analytical model to quantify its level of location privacy by calculating the size of anonymity set of a vehicle. With this model, we can analyze the probability of a vehicle changing pseudonym simultaneously with its neighbor, which can be then used to calculate the size of anonymity set of the vehicle. Further, we investigate the influence of the pseudonym lifetime distribution on the level of location privacy. Research results, which are validated via extensive simulations, show that for the RPC scheme, the uniform pseudonym lifetime distribution can provide better location privacy protection than the reciprocal pseudonym lifetime distribution. In addition, we also discuss the conditional probability of a vehicle changing pseudonym simultaneously with its neighbor given the age of pseudonym used by the neighbor at the time when the vehicle last changed pseudonym, and point out that utilizing the age of pseudonym can improve the level of location privacy.     

An analytical model for bidirectional reflectance factor of multicomponent vegetation canopies

Based on radiative transfer theory in vegetation and geometric-optical principles, an analytical physi-cal mode] for calculating multiangular, multispectral reflectance over a non-random, multiple component vegetation canopy is developed. This model is derived by taking advantages of the previous leaf canopy and multicomponent canopy BRF models. It quantitatively accounts for both the impact of foliage elements' orientation on the canopy hotspot through an innovative algorithm to estimate the hotspot function for any arbitrarily oriented foliage element and contributions of all foliage elements to the reflectance by multiple scattering. Thus, it is characterized by more com-pletely considering the integrative influence of spatial variations in optical and structural properties of all foliage ele-ments on canopy reflectance than any previous analytical BRF models. Simulation results from this model demonstrate that canopy hotspot becomes strongest when the mean inclination angle of foliage elements is ar     

An analytical model of traumatic diffuse brain injury

Diffuse axonal injury (DAI) with prolonged coma has been produced in the primate using an impulsive, rotational acceleration of the head without impact. This pathophysiological entity has been studied subsequently from a biomechanics perspective using physical models of the skull-brain structure. Subjected to identical loading conditions as the primate, these physical models permit one to measure the deformation within the surrogate brain tissue as a function of the forces applied to the head. An analytical model designed to approximate these experiments has been developed in order to facilitate an analysis of the parameters influencing brain deformation. These three models together are directed toward the development of injury tolerance criteria based upon the shear strain magnitude experienced by the deep white matter of the brain. The analytical model geometry consists of a rigid, right-circular cylindrical shell filled with a Kelvin-Voigt viscoelastic material. Allowing no slip on the boundary, the shell is subjected to a sudden, distributed, axisymmetric, rotational load. A Fourier series representation of the load allows unrestricted load-time histories. The exact solution for the relative angular displacement (V) and the infinitesimal shear strain (epsilon) at any radial location in the viscoelastic material with respect to the shell was determined.(ABSTRACT TRUNCATED AT 250 WORDS)     

An analytical model for calculating internal dose conversion coefficients for non-human biota

To assess the radiation burden of non-human living organisms, dose coefficients are available in the literature, precalculated by assuming an ellipsoidal shape of each organism. A previously developed analytical method was applied for the determination of absorbed fractions inside ellipsoidal volumes from alpha, beta, and gamma radiations to the calculation of dose conversion coefficients (DCCs) for 15 reference organisms, animals and plants, either terrestrial, amphibian, or aquatic, and six radionuclides (¹⁴C, ⁹⁰Sr, ⁶⁰Co, ¹³⁷Cs, ²³⁸U, and ²⁴¹Am). The results were compared with the reference values reported in Publication 108 of the International Commission on Radiological Protection, in which a different calculation approach for DCCs was employed. The results demonstrate that the present analytical method, originally intended for applications in internal dosimetry of nuclear medicine therapy, gives consistent results for all the beta-, beta–gamma-, and alpha-emitting radionuclides tested in a wide range of organism masses, between 8 mg and 1.3 kg. The applicability of the method proposed can take advantage from its ease of implementation in an ordinary electronic spreadsheet, allowing to calculate, for virtually all possible radionuclide emission spectra, the DCCs for ellipsoidal models of non-human living organisms in the environment.     

An analytical subthreshold current model for ballistic quantum-wire double-gate MOS transistors

The subthreshold characteristic of ultra-thin (i.e. quantum-wire), ultra-short double-gate transistors (symmetric structures) working in the ballistic regime has been analytically modeled. This model takes into account short-channel effects, quantization effects and source-to-drain tunneling (WKB approximation) in the expression of the subthreshold drain current. Important device parameters, such as I_off-current or subthreshold swing, can be easily evaluated through this full analytical approach, which also provides a complete set of equations for developing equivalent-circuit model used in ICs simulation.     

A model of antiglucocorticoid action for designing a potent glucocorticoid antagonist

We have previously shown that the biological efficacy of an antiglucocorticoid is directly related to its affinity for the glucocorticoid receptor in whole cells at 37 degrees C. We have also shown that RU 486-receptor complexes differ from other antiglucocorticoid-receptor complexes in so far as their affinity is as high at 37 degrees C in whole cells as at 0 degree C in a cell-free system, whereas a decrease by a factor of 5-10 is observed with the other antagonists. The aim of the present paper was to evaluate the contributions of temperature and cellular integrity (or the biological events linked to temperature and cellular integrity) to the affinity of a steroid for its receptor for the purpose of determining the parameters favorable to high affinity, which is the prerequisite of a potent antagonist. We provide evidence showing that: (1) an increase in temperature has an unfavorable effect on the affinity of a glucocorticoid for its receptor (4-6-fold decrease between 0 and 37 degrees C), (2) RU 486, like an agonist, forms a complex with the cytosolic glucocorticoid receptor, which satisfies the criteria for an "activated" complex under "in vitro activating treatment", (3) these biological post-binding events (either agonistic or otherwise nature), which change the nature of the complexes, contribute to compensating for the negative effect of rising temperatures on their apparent dissociation constant. We conclude that potent antiglucocorticoids must have a chemical structure allowing them to induce biological post-binding events, such as receptor activation, but in an abortive form which thus effectively "traps" the receptor in a non-functional state.     

An analytical model of the vestibular evoked myogenic potential

The vestibular evoked myogenic potential (VEMP) can be modeled (scaling factors aside) as a convolution of the motor unit action potential (MUAP) of a representative motor unit, h(t), with the temporal modulation of the MUAP rate of all contributing motor units, r(t). Accordingly, the variance modulation associated with the VEMP can be modeled as a convolution of r(t) with the square of h(t). To get a deeper theoretical understanding of the VEMP phenomenon, a specific realization of this general model is investigated here. Both r(t) and h(t) were derived from a Gaussian probability density function (in the latter case taking the first derivative). The resulting model turned out to be simple enough to be evaluated analytically in the time and in the frequency domain, while still being realistic enough to account for the basic aspects of the VEMP generation. Perhaps the most significant conclusion of this study is that, in the case of noisy data, it may be difficult to falsify the hypothesis of a rate modulation of infinitesimal duration. Thus, certain aspects of the data (particularly the peak amplitudes) can be interpreted using a short-modulation approximation rather than the general model. The importance of this realization arises from the fact that the approximation offers an exceptionally simple and convenient way for a model-based interpretation of experimental data, whereas any attempt to use the general model for that purpose would result in an ill-posed inverse problem that is far from easy to solve.     

An analytical model of temperature regulation in human head

An analytical model of human brain temperature regulation is proposed. The model describes the distribution of brain temperature as a function of internal and external parameters, such as temperature of the incoming arterial blood, blood flow, oxygen consumption rate, ambient temperature, and heat exchange with the environment. It is shown that substantial changes in human brain temperature can be accomplished only through changes in the temperature of the incoming arterial blood or substantial suppression of blood flow. Other parameters can lead only to temperature changes near the brain surface.     

An analysis of the adequacy of the asymmetric carrier model for sugar transport

In 1972, Lieb, W. R.; Stein, W. D. (Biochim. Biophys. Acta 265, 187–207) in their review of sugar transport in human erythrocytes concluded that the conventional two-state carrier model was inconsistent with the experimental data available at that time. Since then, other papers have appeared which question the validity of the model. In this paper, we give a brief derivation of the equations describing the two-state carrier model, and analyze the predictions of the model in the classical experiments, i.e. zero-trans, infinite-cis, and equilibrium exchange. We show that the estimate of the half saturatiion constant of 2.8 mM for glucose at the inner face of the human red cell membrane for the infinite-cis procedure reported by Hankin, B. L., Lieb, W. R. and Stein, W. D ((1972) Biochim. Biophys. Acta 288, 114–126) is unreliable. We note that all of the other experimental findings are consistent with the asymmetric carrier model.     

An analytical model for the ergometer rowing: inverse multibody dynamics analysis

A model for the ergometer rowing exercise is presented in this paper. From the quantitative observations of a particular trajectory (motion), the model is used to determine the moment of the forces produced by the muscles about each joint. These forces are evaluated according to the continuous system of equations of motion. An inverse dynamics analysis is performed in order to predict the joint torques developed by the muscles during the execution of the task. An elementary multibody mechanical system is used as an example to discuss the assumptions and procedures adopted.