A Constructive Heuristic Approach for Single Airport Slot Allocation Problems

With growth in air transportation expected to continue, the mitigation of operational inefficiency and consequent delays is becoming increasingly important. Slot allocation, as a means of demand management at congested airports, has a significant impact on wider airport operations. This requires sophisticated approaches, to intelligently allocate scarce airport resources to unevenly distributed traffic demand for the use of airport facilities. This paper presents a novel heuristic approach to solve the single airport slot allocation problem. The approach has been tested on real-world data from three medium-sized airports. We introduce a constructive heuristic framework which is able to generate feasible solutions to the model. Within this framework, a number of ordering heuristics are developed to order slot requests to be scheduled, and an allocation algorithm is developed to allocate slots to a request determined by the ordering heuristic. Experimental results suggest that the order in which slot requests are scheduled has a significant impact on the solution quality

Targeting lentiviral vectors to antigen-specific immunoglobulins

Gene transfer into B cells by lentivectors can provide an alternative approach to managing B lymphocyte malignancies and autoreactive B cell-mediated autoimmune diseases. These pathogenic B cell Populations can be distinguished by their surface expression of monospecific immunoglobulin. Development of a novel vector system to deliver genes to these specific B cells could improve the safety and efficacy of gene therapy. We have developed an efficient rnethod to target lentivectors to monospecific immunoglobulin-expressing cells in vitro and hi vivo. We were able to incorporate a model antigen CD20 and a fusogenic protein derived from the Sindbis virus as two distinct molecules into the lentiviral Surface. This engineered vector could specifically bind to cells expressing Surface immunoglobulin recognizing CD20 (αCD20), resulting in efficient transduction of target cells in a cognate antigen-dependent manner in vitro, and in vivo in a xenografted tumor model. Tumor suppression was observed in vivo, using the engineered lentivector to deliver a suicide gene to a xenografted tumor expressing αCD20. These results show the feasibility of engineering lentivectors to target immunoglobulin-specific cells to deliver a therapeutic effect. Such targeting lentivectors also Could potentially be used to genetically mark antigen-specific B cells in vivo to study their B cell biology

The ionized nebula surrounding the red supergiant W26 in Westerlund 1

We present Hα images of an ionized nebula surrounding the M2-5Ia red supergiant (RSG) W26 in the massive star cluster Westerlund 1. The nebula consists of a circumstellar shell or ring ∼0.1 pc in diameter and a triangular nebula ∼0.2 pc from the star that in high-resolution Hubble Space Telescope images shows a complex filamentary structure. The excitation mechanism of both regions is unclear since RSGs are too cool to produce ionizing photons and we consider various possibilities. The presence of the nebula, high stellar luminosity and spectral variability suggests that W26 is a highly evolved RSG experiencing extreme levels of mass-loss. As the only known example of an ionized nebula surrounding an RSG W26 deserves further attention to improve our understanding of the final evolutionary stages of massive stars

The scaling attractor and ultimate dynamics for Smoluchowski's coagulation equations

We describe a basic framework for studying dynamic scaling that has roots in dynamical systems and probability theory. Within this framework, we study Smoluchowski's coagulation equation for the three simplest rate kernels $K(x,y)=2$, $x+y$ and $xy$. In another work, we classified all self-similar solutions and all universality classes (domains of attraction) for scaling limits under weak convergence (Comm. Pure Appl. Math 57 (2004)1197-1232). Here we add to this a complete description of the set of all limit points of solutions modulo scaling (the scaling attractor) and the dynamics on this limit set (the ultimate dynamics). The main tool is Bertoin's L\'{e}vy-Khintchine representation formula for eternal solutions of Smoluchowski's equation (Adv. Appl. Prob. 12 (2002) 547--64). This representation linearizes the dynamics on the scaling attractor, revealing these dynamics to be conjugate to a continuous dilation, and chaotic in a classical sense. Furthermore, our study of scaling limits explains how Smoluchowski dynamics ``compactifies'' in a natural way that accounts for clusters of zero and infinite size (dust and gel)

Some Recent Advances in Bound-State Quantum Electrodynamics

We discuss recent progress in various problems related to bound-state quantum electrodynamics: the bound-electron g factor, two-loop self-energy corrections and the laser-dressed Lamb shift. The progress relies on various advances in the bound-state formalism, including ideas inspired by effective field theories such as Nonrelativistic Quantum Electrodynamics. Radiative corrections in dynamical processes represent a promising field for further investigations.Comment: 12 pages, nrc1 LaTeX styl

Randall-Sundrum black holes and strange stars

It has recently been suggested that the existence of bare strange stars is incompatible with low scale gravity scenarios. It has been claimed that in such models, high energy neutrinos incident on the surface of a bare strange star would lead to catastrophic black hole growth. We point out that for the flat large extra dimensional case, the parts of parameter space which give rise to such growth are ruled out by other methods. We then go on to show in detail how black holes evolve in the the Randall-Sundrum two brane scenario where the extra dimensions are curved. We find that catastrophic black hole growth does not occur in this situation either. We also present some general expressions for the growth of five dimensional black holes in dense media.Comment: 16 pages, more numerics has lead to different path to same conclusion. Accepted in PR

Strange Stars with a Density-Dependent Bag Parameter

We have studied strange quark stars in the framework of the MIT bag model, allowing the bag parameter B to depend on the density of the medium. We have also studied the effect of Cooper pairing among quarks, on the stellar structure. Comparison of these two effects shows that the former is generally more significant. We studied the resulting equation of state of the quark matter, stellar mass-radius relation, mass-central-density relation, radius-central-density relation, and the variation of the density as a function of the distance from the centre of the star. We found that the density-dependent B allows stars with larger masses and radii, due to stiffening of the equation of state. Interestingly, certain stellar configurations are found to be possible only if B depends on the density. We have also studied the effect of variation of the superconducting gap parameter on our results.Comment: 23 pages, 8 figs; v2: 25 pages, 9 figs, version to be published in Phys. Rev. (D

A Systematic Review of Patients’ Values, Preferences, and Expectations for the Diagnosis and Treatment of Male Lower Urinary Tract Symptoms

Context: Understanding men's values and preferences in the context of personal, physical, emotional, relational, and social factors is important in optimising patient counselling, facilitating treatment decision-making, and improving guideline recommendations. Objective: To systematically review the available evidence regarding the values, preferences, and expectations of men towards the investigation and treatment (conservative, pharmacological, and surgical) of male lower urinary tract symptoms (LUTS). Evidence acquisition: We searched electronic databases until August 31, 2020 for quantitative and qualitative studies that reported values and preferences regarding the investigation and treatment of LUTS in men. We assessed the quality of evidence and risk of bias using the Grading of Recommendation, Assessment, Development and Evaluation (GRADE) and GRADE Confidence in the Evidence from Reviews of Qualitative Research (CERQual) approaches. Evidence synthesis: We included 25 quantitative studies, three qualitative studies, and one mixed-methods study recruiting 9235 patients. Most men reported urodynamic testing to be acceptable, despite discomfort or embarrassment, as it significantly informs treatment decisions (low certainty evidence). Men preferred conservative and less risky treatment options, but the preference varied depending on baseline symptom severity and the risk/benefit characteristics of the treatment (moderate certainty). Men preferred pharmacological treatments with a low risk of erectile dysfunction and those especially improving urgency incontinence (moderate certainty). Other important preference considerations included reducing the risk of acute urinary retention or surgery (moderate certainty). Conclusions: Men prefer lower-risk management options that have fewer sexual side effects and are primarily effective at improving urgency incontinence and nocturia. Overall, the evidence was rated to be of low to moderate certainty. This review can facilitate the treatment decision-making process and improve the trustworthiness of guideline recommendations. Patient summary: We thoroughly reviewed the evidence addressing men's values and preferences regarding the management of urinary symptoms and found that minimising adverse effects is particularly important. Further research to understand other factors that matter to men is required. (C) 2020 European Association of Urology. Published by Elsevier B.V. All rights reserved.Peer reviewe

Restricting quark matter models by gravitational wave observation

We consider the possibilities for obtaining information about the equation of state for quark matter by using future direct observational data on gravitational waves. We study the nonradial oscillations of both fluid and spacetime modes of pure quark stars. If we observe the $f$ and the lowest $w_{\rm II}$ modes from quark stars, by using the simultaneously obtained radiation radius we can constrain the bag constant $B$ with reasonable accuracy, independently of the $s$ quark mass.Comment: To appear in Phys. Rev.