Analysis of the “Travelling Salesman Problem” and an Application of Heuristic Techniques for Finding a New Solution

In 1832, a German travelling salesman published a handbook describing his profession. Sadly, his name is unknown; he only stated that the book was written by “one old travelling salesman.” However, he has come down in history thanks to a rather simple and quite obvious observation. He pointed out that when one goes on a business trip, one should plan it carefully; by doing so, one can “win” a great deal of time and increase the trip’s “economy.” Two centuries later, mathematicians and scientists are still struggling with what is now known as the “Travelling Salesman Problem” (TSP)

Hopf bifurcation for the hydrogen atom in a circularly polarized microwave field

We consider the Rydberg electron in a circularly polarized microwave field, whose dynamics is described by a Hamiltonian depending on one parameter, K¿>¿0. The corresponding Hamiltonian system of ODE has two equilibrium points L1 (unstable for all K and energy value h(L1)) and L2 (a center for K¿¿Kcrit, with energy value h(L2)). We study the Hamiltonian-Hopf bifurcation phenomena that take place for K close to Kcrit around L2. First, a local analysis based on the computation of the integrable normal form up to a finite order is carried out and the steps for the computation of this (resonant) normal form are explained in a constructive manner. The analysis of the normal form obtained allows: to claim the type of the Hopf bifurcation –supercritical–; to study the local behavior of the electron in a neighborhood of the equilibrium L2 for the original non integrable Hamiltonian (as a perturbative approach from the integrable normal form); to obtain (approximations for) the parametrizations of the relevant invariant objects that take place due to the bifurcation (periodic orbits and invariant manifolds of L2). We compute numerically such objects and analyse not only the local picture of the dynamics close to L2, but also a global description of the dynamics and the effect of the Hopf bifurcation as well as other objects that organize the dynamics are discussed. We conclude that, for K close to Kcrit and the energy level h(L2), the Hopf bifurcation has essentially no effect on the dynamics from a physical point of view. However, for bigger values of K¿>¿Kcrit, the Hopf bifurcation has a dramatic effect: different kind of orbits coexist, mostly chaotic. Such orbits provide a ionization mechanism with several passages far from and close to L2 before ionizing. Surprisingly enough, also robust confinement regions (where the electron remains confined for ever), exist in the middle of chaotic areasPeer ReviewedPostprint (published version

The impact of peripheral arterial disease on patients with mechanical circulatory support.

Background: Left ventricular assist devices (LVAD) are indicated as bridging or destination therapy for patients with advanced (Stage D) heart failure and reduced ejection fraction (HFrEF). Due to the clustering of the mutual risk factors, HFrEF patients have a high prevalence of peripheral arterial disease (PAD). This, along with the fact that continuous flow LVAD influence shear stress on the vasculature, can further deteriorate the PAD. Methods: We queried the National Inpatient Sample (NIS) database (2002-2014) to identify the burden of pre-existing PAD cases, its association with LVAD, in-hospital mortality, and other complications of LVAD. The adjusted odds ratio (aOR) and 95% confidence interval (CI) were calculated using the Cochran-Mantel-Haenszel test. Results: A total of 20,817 LVAD patients, comprising of 1,625 (7.8%) PAD and 19,192 (91.2%) non-PAD patients were included in the study. The odds of in-hospital mortality in PAD patients were significantly higher compared to non-PAD group (OR 1.29, CI, 1.07-1.55, P = 0.007). The PAD group had significantly higher adjusted odds as compared to non-PAD group for acute myocardial infarction (aOR 1.29; 95% CI, 1.07-1.55, P = 0.007), major bleeding requiring transfusion (aOR, 1.286; 95% CI, 1.136-1.456, P \u3c 0.001), vascular complications (aOR, 2.360; 95% CI, 1.781-3.126, P \u3c 0.001), surgical wound infections (aOR, 1.50; 95% CI, 1.17-1.94, P = 0.002), thromboembolic complications (aOR, 1.69; 95% CI, 1.36-2.10, P \u3c 0.001), implant-related complications (aOR, 1.47; 95% CI, 1.19-1.80, P \u3c 0.001), and acute renal failure (aOR, 1.26; 95% CI, 1.12-1.43, P \u3c 0.001). Conclusion: PAD patients can have high LVAD associated mortality as compared to non-PAD

La Estabilidad de Buques en la Organización Marítima Internacional y la contribución de España

Actualmente y durante los últimos años, el desarrollo de la normativa de estabilidad ha sido unos de los protagonistas en la Organización Marítima Internacional, de las Naciones Unidas. Estos trabajos han sido llevados a cabo, mayormente, en el Subcomité SLF donde España ha estado presente en los principales grupos de trabajo: estabilidad sin avería, donde se ha llevado a cabo la revisión del código de estabilidad sin avería; estabilidad en averías, donde se ha desarrollado el nuevo método probabilístico harmonizado; y pequeños buques de pesca, donde España es responsable de la redacción del capítulo relativo a estabilidad. La representación de España ha estado involucrada en muchos de esos cambios y este artículo presenta las colaboraciones de España en dicho desarrollo. ABSTRACT Today and during the last years, the development of the rules and regulations on stability has kept busy the main agenda of the International Maritime Organization of the United Nations. This activity has been mainly carried out in the SLF Sub-Committee (Stability, Load Lines and Fishing Vessels) where Spain has been a prominent actor in various working groups: intact stability, where a complete revision of the Code has been undertaken; damage stability, where a new harmonized probabilistic method has been developed; and small fishing vessels, where Spain has been responsible for the development of the chapter related to stability. The representatives of Spain have been deeply involved in some of those changes stated above and this paper presents its major contributions on all these developments

Sustainable Technology for Person-Centered Accessible Integrated Multimodal Information Systems

This paper reports on a mobility management technology project conducted by the GeoGraphics Laboratory at Bridgewater State University in Bridgewater, Massachusetts, in the Northeastern United States (U.S.). This study is a part of a much larger mobility management technology deployment by the Cape Cod Regional Transit Authority (CCRTA) that deployed integrated intermodal intelligent transportation system (ITS) to support the mobility of a metropolitan region that has a high proportion of elderly residents and persons with disabilities and is a significant tourist destination for national and international travelers. This paper reports on a research project that is developing smartphone applications to provide travelers using transit with navigational tools and real-time spatial information to optimize their travel experience. The smart phone applications are written using the Android 2.2, Windows 7.5, and Apple iOS 4 operating systems. The applications provide the traveler with schedules for every CCRTA regional and shuttle route, estimated time of arrival (ETA), and bus tracking maps (Google and Bing Maps) that locate the transit vehicle and the consumer on the same map as well as text based vehicle tracking. There is an on-line tutorial on how to use the smartphone application. It also provides features that will provide emergency communication with care givers on the consumer’s travel status. The research has developed these transit navigation tools on the three most popular operating systems for smart phones using a widely available cellular carrier. An associated regional capital infrastructure project is bringing state-of-the-art broadband capability and the potential for 4G wireless infrastructure to the most rural “last mile” areas of the Cape Cod Region. These improvements to wireless communications can provide significant benefits to the safety and security of travelers with disabilities

Ataxia with oculomotor apraxia type 2: clinical, biological and genotype/phenotype correlation study of a cohort of 90 patients

Ataxia with oculomotor apraxia type 2 (AOA2) is an autosomal recessive disease due to mutations in the senataxin gene, causing progressive cerebellar ataxia with peripheral neuropathy, cerebellar atrophy, occasional oculomotor apraxia and elevated alpha-feto-protein (AFP) serum level. We compiled a series of 67 previously reported and 58 novel ataxic patients who underwent senataxin gene sequencing because of suspected AOA2. An AOA2 diagnosis was established for 90 patients, originating from 15 countries worldwide, and 25 new senataxin gene mutations were found. In patients with AOA2, median AFP serum level was 31.0 mu g/l at diagnosis, which was higher than the median AFP level of AOA2 negative patients: 13.8 mu g/l, P = 0.0004; itself higher than the normal level (3.4 mu g/l, range from 0.5 to 17.2 mu g/l) because elevated AFP was one of the possible selection criteria. Polyneuropathy was found in 97.5% of AOA2 patients, cerebellar atrophy in 96%, occasional oculomotor apraxia in 51%, pyramidal signs in 20.5%, head tremor in 14%, dystonia in 13.5%, strabismus in 12.3% and chorea in 9.5%. No patient was lacking both peripheral neuropathy and cerebellar atrophy. The age at onset and presence of occasional oculomotor apraxia were negatively correlated to the progression rate of the disease (P = 0.03 and P = 0.009, respectively), whereas strabismus was positively correlated to the progression rate (P = 0.03). An increased AFP level as well as cerebellar atrophy seem to be stable in the course of the disease and to occur mostly at or before the onset of the disease. One of the two patients with a normal AFP level at diagnosis had high AFP levels 4 years later, while the other had borderline levels. The probability of missing AOA2 diagnosis, in case of sequencing senataxin gene only in non-Friedreich ataxia non-ataxia-telangiectasia ataxic patients with AFP level >= 7 mu g/l, is 0.23% and the probability for a non-Friedreich ataxia non-ataxia-telangiectasia ataxic patient to be affected with AOA2 with AFP levels >= 7 mu g/l is 46%. Therefore, selection of patients with an AFP level above 7 mu g/l for senataxin gene sequencing is a good strategy for AOA2 diagnosis. Pyramidal signs and dystonia were more frequent and disease was less severe with missense mutations in the helicase domain of senataxin gene than with missense mutations out of helicase domain and deletion and nonsense mutations (P = 0.001, P = 0.008 and P = 0.01, respectively). The lack of pyramidal signs in most patients may be explained by masking due to severe motor neuropathy

Perceptions of Secondary Education Teachers Working in an Inclusive Setting

This dissertation in practice addresses the continuous underperformance of students with disabilities (SWD) on standardized assessments when compared to their non-disabled peers. This dissertation on the complex problem of practice investigates secondary education teachers\u27 perceptions of students with disabilities and their ability to be included in the general education classroom. The purpose of this research is to develop a professional development framework to enhance inclusive practices. Students with disabilities nationwide are increasingly taught in the general education classroom in order to provide them access to their least restrictive environment and instruction of the general education curriculum. The beliefs held by teachers about students with disabilities and their inclusion in the general education classroom is one key variable to the successful inclusion as measured by student outcomes. To provide necessary support, it is imperative to understand teachers\u27 attitude towards students with disabilities and their inclusion in the general education classroom. Based on the survey results and relevant research, the professional development framework to enhance inclusive practices was developed and will focus on three elements: (a) school culture and understanding of inclusion, (b) effective inclusive teaching strategies, and (c) collaboration models and techniques. The goal of the professional development framework is for administrators and other school leaders to provide appropriate learning opportunities for teachers to enhance their understanding of inclusion and to provide them strategies and techniques to improve student outcomes in an effort to close the achievement gap between students with and without disabilities

INCOME GENERATION SCHEMES FOR SUSTAINABLE DEVELOPMENT OF TRIBAL WOMEN

Purpose of the study: The study tried to evaluate two issues which are socio-economic conditions of tribal women and the impact of welfare schemes financing by banks for income generation among tribal women. Methodology: This empirical research adopted a quantitative method by distributing a schedule to 120 tribal women located in a rural-based Khammam district of Telangana state. The data analyzed by using the one-way ANOVA, mean, regression analysis and standard deviation (S.D.) with the assistance of Statistical Package for Social Sciences to determining the impact of income generation schemes on socio-economic conditions. Main Findings: This study found that incomes are improved phenomenally after availing welfare schemes targeted at tribal women. However, the tribal women are needed to facilitate awareness of various schemes on circulation by the Government. The known income generation schemes were impacted positively among few tribal women and they have expressed satisfaction as there was significant empowerment in their livelihoods. Applications of this study: The findings of the study are useful for the government in implementing income generation activities to strengthen tribal women economically, socially and politically. It would be relevant to apply solutions for the problems encountering by tribal women. Novelty/Originality of this study: The impact of income generation schemes has been addressed categorically concerning empowerment. Therefore a determined plan of implementation of further action can significantly empower the tribal women in all respects