bluuebunny/crossref_metadata_2025_split huggingface dataset:
Worst Case and Probabilistic Analysis of the 2-Opt Algorithm for the TSP
Authors: Englert Matthias , Röglin Heiko , Vöcking Berthold 
Published: June 2013

Abstract2-Opt is probably the most basic local search heuristic for the TSP. This heuristic achieves amazingly good results on “real world” Euclidean instances both with respect to running time and approximation ratio. There are numerous experimental studies on the performance of 2-Opt. However, the theoretical knowledge about this heuristic is still very limited. Not even its worst case running time on 2-dimensional Euclidean instances was known so far. We clarify this issue by presenting, for every$p\in\mathbb{N}$, a family ofLpinstances on which 2-Opt can take an exponential number of steps.Previous probabilistic analyses were restricted to instances in whichnpoints are placed uniformly at random in the unit square [0,1]2, where it was shown that the expected number of steps is bounded by$\tilde{O}(n^{10})$for Euclidean instances. We consider a more advanced model of probabilistic instances in which the points can be placed independently according to general distributions on [0,1]d, for an arbitraryd≥2. In particular, we allow different distributions for different points. We study the expected number of local improvements in terms of the numbernof points and the maximal densityϕof the probability distributions. We show an upper bound on the expected length of any 2-Opt improvement path of$\tilde{O}(n^{4+1/3}\cdot\phi^{8/3})$. When starting with an initial tour computed by an insertion heuristic, the upper bound on the expected number of steps improves even to$\tilde{O}(n^{4+1/3-1/d}\cdot\phi^{8/3})$. If the distances are measured according to the Manhattan metric, then the expected number of steps is bounded by$\tilde{O}(n^{4-1/d}\cdot\phi)$. In addition, we prove an upper bound of$O(\sqrt[d]{\phi})$on the expected approximation factor with respect to allLpmetrics.Let us remark that our probabilistic analysis covers as special cases the uniform input model withϕ=1 and a smoothed analysis with Gaussian perturbations of standard deviationσwithϕ∼1/σd.
In silico aided metabolic engineering of Klebsiella oxytoca and fermentation optimization for enhanced 2,3-butanediol production
Authors: Park Jong Myoung , Song Hyohak , Lee Hee Jong , Seung Doyoung 
Published: June 2013

Abstract
Klebsiella oxytoca naturally produces a large amount of 2,3-butanediol (2,3-BD), a promising bulk chemical with wide industrial applications, along with various byproducts. In this study, the in silico gene knockout simulation of K. oxytoca was carried out for 2,3-BD overproduction by inhibiting the formation of byproducts. The knockouts of ldhA and pflB genes were targeted with the criteria of maximization of 2,3-BD production and minimization of byproducts formation. The constructed K. oxytoca ΔldhA ΔpflB strain showed higher 2,3-BD yields and higher final concentrations than those obtained from the wild-type and ΔldhA strains. However, the simultaneous deletion of both genes caused about a 50 % reduction in 2,3-BD productivity compared with K. oxytoca ΔldhA strain. Based on previous studies and in silico investigation that the agitation speed during 2,3-BD fermentation strongly affected cell growth and 2,3-BD synthesis, the effect of agitation speed on 2,3-BD production was investigated from 150 to 450 rpm in 5-L bioreactors containing 3-L culture media. The highest 2,3-BD productivity (2.7 g/L/h) was obtained at 450 rpm in batch fermentation. Considering the inhibition of acetoin for 2,3-BD production, fed-batch fermentations were performed using K. oxytoca ΔldhA ΔpflB strain to enhance 2,3-BD production. Altering the agitation speed from 450 to 350 rpm at nearly 10 g/L of acetoin during the fed-batch fermentation allowed for the production of 113 g/L 2,3-BD, with a yield of 0.45 g/g, and for the production of 2.1 g/L/h of 2,3-BD.
THE PRICING OF MORTALITY-LINKED CONTINGENT CLAIMS: AN EQUILIBRIUM APPROACH
Authors: Tsai Jeffrey T. , Tzeng Larry Y. 
Published: June 2013

AbstractThis study introduces an equilibrium approach to price mortality-linked securities in a discrete time economy, assuming that the mortality rate has a transformed normal distribution. This pricing method complements current studies on the valuation of mortality-linked securities, which only have discrete trading opportunities and insufficient market trading data. Like the Wang transform, the valuation relationship is still risk-neutral (preference-free) and the mortality-linked security is priced as the expected value of its terminal payoff, discounted by the risk-free rate. This study provides an example of pricing the Swiss Re mortality bond issued in 2003 and obtains an approximated closed-form solution.
STATISTICAL INFERENCE FOR COPULAS IN HIGH DIMENSIONS: A SIMULATION STUDY
Authors: Embrechts Paul , Hofert Marius 
Published: June 2013

AbstractStatistical inference for copulas has been addressed in various research papers. Due to the complicated theoretical results, studies have been carried out mainly in the bivariate case, be it properties of estimators or goodness-of-fit tests. However, from a practical point of view, higher dimensions are of interest. This work presents the results of large-scale simulation studies with particular focus on the question to what extent dimensionality influences point and interval estimators.
SOME DISTRIBUTIONAL PROPERTIES OF A CLASS OF COUNTING DISTRIBUTIONS WITH CLAIMS ANALYSIS APPLICATIONS
Authors: Willmot Gordon E. , Woo Jae-Kyung 
Published: June 2013

AbstractWe discuss a class of counting distributions motivated by a problem in discrete surplus analysis, and special cases of which have applications in stop-loss, discrete Tail value at risk (TVaR) and claim count modelling. Explicit formulas are developed, and the mixed Poisson case is considered in some detail. Simplifications occur for some underlying negative binomial and related models, where in some cases compound geometric distributions arise naturally. Applications to claim count and aggregate claims models are then given.
Large-time evolution of statistical moments of wind–wave fields
Authors: Annenkov Sergei Y. , Shrira Victor I. 
Published: June 2013

AbstractWe study the long-term evolution of weakly nonlinear random gravity water wave fields developing with and without wind forcing. The focus of the work is on deriving, from first principles, the evolution of the departure of the field statistics from Gaussianity. Higher-order statistical moments of elevation (skewness and kurtosis) are used as a measure of this departure. Non-Gaussianity of a weakly nonlinear random wave field has two components. The first is due to nonlinear wave–wave interactions. We refer to this component as ‘dynamic’, since it is linked to wave field evolution. The other component is due to bound harmonics. It is non-zero for every wave field with finite amplitude, contributes both to skewness and kurtosis of gravity water waves and can be determined entirely from the instantaneous spectrum of surface elevation. The key result of the work, supported both by direct numerical simulation (DNS) and by the analysis of simulated and experimental (JONSWAP) spectra, is that in generic situations of a broadband random wave field the dynamic contribution to kurtosis is small in absolute value, and negligibly small compared with the bound harmonics component. Therefore, the latter dominates, and both skewness and kurtosis can be obtained directly from the instantaneous wave spectra. Thus, the departure of evolving wave fields from Gaussianity can be obtained from evolving wave spectra, complementing the capability of forecasting spectra and capitalizing on the existing methodology. We find that both skewness and kurtosis are significant for typical oceanic waves; the non-zero positive kurtosis implies a tangible increase of freak wave probability. For random wave fields generated by steady or slowly varying wind and for swell the derived large-time asymptotics of skewness and kurtosis predict power law decay of the moments. The exponents of these laws are determined by the degree of homogeneity of the interaction coefficients. For all self-similar regimes the kurtosis decays twice as fast as the skewness. These formulae complement the known large-time asymptotics for spectral evolution prescribed by the Hasselmann equation. The results are verified by the DNS of random wave fields based on the Zakharov equation. The predicted asymptotic behaviour is shown to be very robust: it holds both for steady and gusty winds.
Bifurcation in a thin liquid film flowing over a locally heated surface
Authors: Katkar Harshwardhan H. , Davis Jeffrey M. 
Published: June 2013

AbstractWe investigate the nonlinear dynamics of a two-dimensional film flowing down a finite heater, for a non-volatile and a volatile liquid. An oscillatory instability is predicted beyond a critical value of the Marangoni number using linear stability theory. Continuation along the Marangoni number using a nonlinear evolution equation is employed to trace the bifurcation diagram associated with the oscillatory instability. Hysteresis, a characteristic attribute of a subcritical Hopf bifurcation, is observed in a critical parametric region. The bifurcation is universally observed for both a non-volatile film and a volatile film.
New exact relations for easy recovery of steady wave profiles from bottom pressure measurements
Authors: Clamond Didier 
Published: June 2013

AbstractThis paper is about the determination of a free surface wave profile from a given pressure distribution at the bottom. For a two-dimensional irrotational steady surface water wave propagating over a flat horizontal bed, this problem is solved analytically in an implicit form. Explicit solutions can be easily obtained numerically via fixed point iterations, whose convergence is outlined mathematically and numerically. This new surface reconstruction procedure does not involve the resolution of a differential or an integral equation, i.e. the surface is given by algebraic local relations. Thus, this formulation permits the free surface recovery in a simpler and more efficient way than previous methods.
Supplementation of diets with bovine colostrum influences immune function in dogs
Authors: Satyaraj Ebenezer , Reynolds Arleigh , Pelker Robyn , Labuda Jeff , Zhang Peifang , Sun Peichuan 
Published: June 2013

While the need for colostrum in neonates is well established, the systemic effect of feeding bovine colostrum (BC) to adult humans is gaining increasing attention. However, no systematic studies evaluating the immunomodulatory effect of BC in dogs have been reported. The aim of the present study was to evaluate the immunomodulatory effect of dietary supplementation of BC in dogs. The study was conducted in two phases: pre-test (8 weeks) and test (40 weeks), with twenty-four dogs (mean age 2·5 years) randomised into two groups. In the ‘pre-test’ phase, both groups were fed a nutritionally complete diet. At the end of the ‘pre-test’ phase, all dogs received a canine distemper virus (CDV) vaccine, and dogs in the ‘test group’ were switched to a diet supplemented with 0·1 % spray-dried BC. Response to the CDV vaccine was evaluated by measuring vaccine-specific plasma IgG levels. Gut-associated lymphoid tissue response was assessed by measuring faecal IgA levels. Gut microbiota were evaluated by the temporal temperature gel electrophoresis methodology. Dogs fed the BC-supplemented diet demonstrated a significantly higher vaccine response and higher levels of faecal IgA when compared with the control group. Supplementing diets with BC also resulted in significantly increased gut microbiota diversity and stability in the test group. In conclusion, diets supplemented with BC significantly influence immune response in dogs.
Effects of nitric oxide synthase inhibition on glutamine action in a bacterial translocation model
Authors: Santos Rosana G. C. , Quirino Iara E. P. , Viana Mirelle L. , Generoso Simone V. , Nicoli Jacques R. , Martins Flaviano S. , Nogueira-Machado José A. , Arantes Rosa M. E. , Correia Maria I. T. D. , Cardoso Valbert N. 
Published: June 2013

Glutamine may be a precursor for NO synthesis, which may play a crucial role in bacterial translocation (BT). The goal of the present study was to investigate the potential effects of glutamine on BT and the immunological response in an experimental model of NO synthase inhibition by NG-nitro-L-arginine methyl ester (l-NAME). Mice were randomly assigned to four groups: sham; intestinal obstruction (IO); IO+500 mg/kg per d glutamine (GLN); IO+GLN plus 10 mg/kg per d l-NAME (GLN/LN). The groups were pretreated for 7 d. BT was induced by ileal ligation and was assessed 18 h later by measuring the radioactivity of 99mTc-Escherichiacoli in the blood and organs. Mucosal damage was determined using a histological analysis. Intestinal permeability (IP) was assessed by measuring the levels of 99mTc-diethylenetriaminepentaacetic acid in the blood at 4, 8 and 18 h after surgery. IgA and cytokine concentrations were determined by ELISA in the intestinal fluid and plasma, respectively. BT was increased in the GLN/LN and IO groups than in the GLN and sham groups. IP and intestinal mucosa structure of the sham, GLN and GLN/LN groups were similar. The GLN group had the highest levels of interferon-γ, while IL-10 and secretory IgA levels were higher than those of the IO group but similar to those of the GLN/LN group. The present results suggest that effects of the glutamine pathway on BT were mediated by NO. The latter also interferes with the pro-inflammatory systemic immunological response. On the other hand, IP integrity preserved by the use of glutamine is independent of NO.
Observation of repetitive bursts in emission of fast ions and neutrons in sub-nanosecond laser-solid experiments
Authors: Krása J. , Klír D. , Velyhan A. , Margarone D. , Krouský E. , Jungwirth K. , Skála J. , Pfeifer M. , Kravárik J. , Kubeš P. , Řezáč K. , Ullschmied J. 
Published: June 2013

AbstractA massive deuterated polyethylene target was exposed to laser intensities of about 3 × 1016 W/cm2 employing the 3-TW Prague Asterix Laser System (PALS). We achieved a yield of 2 × 108 neutrons per laser shot. Average time-of-flight signals of scintillation detectors operated in current mode reveal broad energy spectra of fusion neutrons with dominating energy of about 2.45 MeV. The energy dependence of the neutron yield shows a consistency in results of nanosecond, picosecond and sub-picosecond experiments. Here we also show that ions emitted in the backward direction from the front target surface have a multi-peak energy spectrum, which is caused by burst emission mechanisms.
Monitoring, firms’ compliance and imposition of fines: evidence from the Federal Industrial Inspection Program in Mexico City
Authors: Escobar Ninel , Chávez Carlos 
Published: June 2013

AbstractWe analyze the performance of the Federal Industrial Inspection Program operated by the Federal Attorney for Environmental Protection (PROFEPA) in Mexico City. We seek to answer three questions: What drives the inspections? What determines non-compliance? And what drives imposition of fines? We use firm-level data that identify certain characteristics of the firms, PROFEPA's inspections, compliance results and fines for all air polluting firms under the Program during the period January 2000–October 2008. We obtain three main results. First, PROFEPA's inspections have focused on larger firms devoted to industrial activities located in poor and dense municipalities. Second, past inspections were significant and have a high marginal effect on compliance. Third, the severity of the infraction was not relevant to the decision to impose a fine but rather to its amount.
Life insurance underwriting in the United States – yesterday, today and tomorrow
Authors: Klein Allen M. 
Published: June 2013

AbstractUnderwriting in the United States (US) life insurance marketplace has evolved tremendously over the last several decades. This paper will take a brief look at that history, from the older underwriting techniques still in use today to the introduction of smoker/nonsmoker distinctions in about 1980 to the evolution of preferred underwriting in the late 1980s, and finally to a movement toward simplified issue underwriting and a new approach to older age underwriting today.
Is there a place in the UK Defined Contribution pensions market for a guaranteed savings product?
Authors: Eason S. , Barker P. , Foroughi G. , Harsant J. , Hunter D. , Jarvis S. , Jones G. , Knava V. , Murphy P. , Murray K. , Muthulingam J. , Odozi N. , Page T. , Washoma K. , Webb A. 
Published: June 2013

AbstractThe UK has seen a significant transition from Defined Benefit (“DB”) to Defined Contribution (“DC”) for occupational pension saving. The planned automatic enrolment program starting in 2012 is expected to increase the use of DC. The main features of DC are that investment risk falls onto the individual during the pre-retirement phase and that there are no guarantees as to investment returns or the level of pension. In July 2012, Steve Webb, the Pensions Minister, challenged industry to think hard about meeting the need for more certainty about pension savings in DC plans and to consider providing an affordable ‘Money Safe’ guarantee where the member would get back at least the nominal value of their contributions (individual, employer and tax relief). This paper explores whether this is viable for the mass market.
Texture Indicators for Segmentation of Polyomavirus Particles in Transmission Electron Microscopy Images
Authors: Proença Maria C. , Nunes José F.M. , de Matos António P.A. 
Published: June 2013

AbstractA fully automatic approach to locate polyomavirus particles in transmission electron microscopy images is presented that can localize intact particles, many damaged capsids, and an acceptable percentage of superposed ones. Performance of the approach is quantified in 25 electron micrographs containing nearly 390 particles and compared with the interpretation of the micrographs by two independent electron microscopy experts. All parameterization is based on the particle expected dimensions. This approach uses indicators calculated from the local co-occurrence matrix of gray levels to assess the textured pattern typical of polyomavirus and prune the initial set of candidates. In more complicated backgrounds, about 2–10% of the elements survive. A restricted set of the accepted points is used to evaluate the typical average and variance and to reduce the set of survivors accordingly. These intermediate points are evaluated using (i) a statistical index concerning the radiometric distribution of a circular neighborhood around the centroid of each candidate and (ii) a structural index resuming the expected morphological characteristics of eight radial intensity profiles encompassing the area of the possible particle. This hierarchical approach attains 90% efficiency in the detection of entire virus particles, tolerating a certain lack of differentiation in the borders and a certain amount of shape alterations.
Understanding the needs of family caregivers of older adults dying with dementia
Authors: Thompson Genevieve N. , Roger Kerstin 
Published: June 2013

AbstractObjectives:A challenge in understanding the needs of dementia family caregivers (DFC) within the purview of dementia as a terminal illness rests on the fact that literature in this area is dispersed across disciplines and not specifically grounded within the realm of palliative care. The objective of this paper is to describe the domains of DFC needs and their impact on the delivery of palliative care services.Methods:A literature search pertaining to dementia family caregivers and palliative/end-of-life care was conducted using the databases Medline, CINHAL, Ageline, PsychInfo, and Scopus for articles published in the English language between 1997 and 2011.Results:Supporting family caregivers of individuals with dementia throughout the disease trajectory requires consideration of caregivers : (1) physical, emotional, and psychological needs; (2) information and decisional support needs; and (3) instrumental support needs. The unique nature and prolonged duration of these needs directly influences the palliative care services and supports required by these family caregivers.Significance of results:Understanding the scope of DFC needs help further our understanding of how these needs may impact the delivery of palliative care services, and assists in developing a model of care for those dying from dementia and for their family caregivers.
Graphical design method for unequal power dividers based on phase-balanced SIW tee-junctions
Authors: Contreras Soraya , Peden Alain 
Published: June 2013

This paper presents a detailed procedure to design substrate integrated waveguide (SIW) Tee-junctions with wide-range split-power ratio (from 1:1 to 1:8) and phase-balanced outputs. A set of curves was generated using an electromagnetic (EM) simulator to graphically determine the required parameters for the desired junction. Since such curves are provided, no further electromagnetic simulation is required when applying the proposed method. Input return loss at central frequency is guaranteed to be better than 18 dB. If an optimization procedure is required, the parameters obtained from this methodology may be used as initial values for such a process. Moreover, design rules are given for implementing 1 → 2Nunequal power dividers with phase-balanced outputs. To demonstrate the accuracy of the proposed graphical method, three implementation examples are provided: two Tee-junctions and a 1 → 4 power divider.
BDNF–TrkB signaling in striatopallidal neurons controls inhibition of locomotor behavior
Authors: Besusso Dario , Geibel Mirjam , Kramer Dana , Schneider Tomasz , Pendolino Valentina , Picconi Barbara , Calabresi Paolo , Bannerman David M. , Minichiello Liliana 
Published: June 2013

AbstractThe physiology of brain-derived neurotrophic factor signaling in enkephalinergic striatopallidal neurons is poorly understood. Changes in cortical Bdnf expression levels, and/or impairment in brain-derived neurotrophic factor anterograde transport induced by mutant huntingtin (mHdh) are believed to cause striatopallidal neuron vulnerability in early-stage Huntington’s disease. Although several studies have confirmed a link between altered cortical brain-derived neurotrophic factor signaling and striatal vulnerability, it is not known whether the effects are mediated via the brain-derived neurotrophic factor receptor TrkB, and whether they are direct or indirect. Using a novel genetic mouse model, here, we show that selective removal of brain-derived neurotrophic factor–TrkB signaling from enkephalinergic striatal targets unexpectedly leads to spontaneous and drug-induced hyperlocomotion. This is associated with dopamine D2 receptor-dependent increased striatal protein kinase C and MAP kinase activation, resulting in altered intrinsic activation of striatal enkephalinergic neurons. Therefore, brain-derived neurotrophic factor/TrkB signaling in striatopallidal neurons controls inhibition of locomotor behavior by modulating neuronal activity in response to excitatory input through the protein kinase C/MAP kinase pathway.