Convergent Analytic Solutions for Homoclinic Orbits in Reversible and Non-reversible Systems

In this paper, convergent, multi-infinite, series solutions are derived for the homoclinic orbits of a canonical fourth-order ODE system, in both reversible and non-reversible cases. This ODE includes traveling-wave reductions of many important nonlinear PDEs or PDE systems, for which these analytical solutions would correspond to regular or localized pulses of the PDE. As such, the homoclinic solutions derived here are clearly topical, and they are shown to match closely to earlier results obtained by homoclinic numerical shooting. In addition, the results for the non-reversible case go beyond those that have been typically considered in analyses conducted within bifurcation-theoretic settings. We also comment on generalizing the treatment here to parameter regimes where solutions homoclinic to exponentially small periodic orbits are known to exist, as well as another possible extension placing the solutions derived here within the framework of a comprehensive categorization of ALL possible traveling-wave solutions, both smooth and non-smooth, for our governing ODE.Comment: arXiv admin note: text overlap with arXiv:math-ph/060606

Post-Double Hopf Bifurcation Dynamics and Adaptive Synchronization of a Hyperchaotic System

In this paper a four-dimensional hyperchaotic system with only one equilibrium is considered and its double Hopf bifurcations are investigated. The general post-bifurcation and stability analysis are carried out using the normal form of the system obtained via the method of multiple scales. The dynamics of the orbits predicted through the normal form comprises possible regimes of periodic solutions, two-period tori, and three-period tori in parameter space. Moreover, we show how the hyperchaotic synchronization of this system can be realized via an adaptive control scheme. Numerical simulations are included to show the effectiveness of the designed control

Investigation of perognathus as an experi- mental organism for research in space biology progress report, 1 apr. - 30 jun. 1965

Reproduction of mice in confinemen

Investigation of perognathus as an experimen- tal organism for research in space biology fourth quarterly progress report, 1 jul. - 30 sep. 1964

Perognathus investigated as experimental organism for space biology researc

Investigation of Perognathus as an experimental organism for research in space biology Progress report, 1 Jul. - 30 Sep. 1965

Histopathology of pocket mouse intestine mucous after irradiation - growth and development data on laboratory pocket mous

Towards a Typology of Corporate Responsibility in Different Governance Contexts

This paper develops a typology of different country governance contexts, in which we propose four broad categories of countries in Sub-Saharan Africa. Our analysis measures the most appropriate methods for helping to create a climate that is receptive to fostering corporate accountability. Our criteria are based on several different factors, none of which is determinative: the natural resources of the country; the country\u27s dependence on one commodity; the corruption level; the stability and accountability of the government; the state of civil society; and the existence of ongoing conflict. Examining these factors together results in measuring not just the country\u27s receptivity to change, but also the means for producing change. At one end of the spectrum, what we label Category 0 countries, are nations with economies and governments that are so poorly managed that there is little multinational investment - sometimes even in the context of lucrative investment opportunities. At the other end lie those countries with acceptable levels of good governance, more developed economies and markets, and with, consequently, a comparatively high level of both domestic and multinational corporate investment. We examine the appropriateness of strategies to apply external or internal pressure in different types of countries. Next, we discuss the affects of applying the proposed intervention strategies to the countries, addressing both short and long-term expected results. We find that in Category 0 countries, with extremely low levels of international investment, strategies should focus on improving governance and overall human welfare, which often could lead to welcoming international corporate investment. Other categories of countries, with greater - and often problematic - international corporate involvement, require different types of approaches

Towards a Typology of Corporate Responsibility in Different Governance Contexts

This paper develops a typology of different country governance contexts, in which we propose four broad categories of countries in Sub-Saharan Africa. Our analysis measures the most appropriate methods for helping to create a climate that is receptive to fostering corporate accountability. Our criteria are based on several different factors, none of which is determinative: the natural resources of the country; the country\u27s dependence on one commodity; the corruption level; the stability and accountability of the government; the state of civil society; and the existence of ongoing conflict. Examining these factors together results in measuring not just the country\u27s receptivity to change, but also the means for producing change. At one end of the spectrum, what we label Category 0 countries, are nations with economies and governments that are so poorly managed that there is little multinational investment - sometimes even in the context of lucrative investment opportunities. At the other end lie those countries with acceptable levels of good governance, more developed economies and markets, and with, consequently, a comparatively high level of both domestic and multinational corporate investment. We examine the appropriateness of strategies to apply external or internal pressure in different types of countries. Next, we discuss the affects of applying the proposed intervention strategies to the countries, addressing both short and long-term expected results. We find that in Category 0 countries, with extremely low levels of international investment, strategies should focus on improving governance and overall human welfare, which often could lead to welcoming international corporate investment. Other categories of countries, with greater - and often problematic - international corporate involvement, require different types of approaches

La pietra naturale nei beni culturali

Le pietre ornamentali ricoprono un ruolo fondamentale per quei beni culturali costituiti parzialmente o interamente in materiale lapideo. In un contesto come quello italiano, la conoscenza dei litotipi utilizzati in ciascun ambito regionale, sia per le produzioni artistiche di pregio che per l’edilizia corrente, riveste certamente una particolare importanza. Infatti, l’impiego della pietra ha da sempre connotato in maniera determinante il paesaggio urbano e rurale. Lo studio dei litotipi ornamentali, la loro caratterizzazione e la loro conservazione rivolge l’attenzione sui materiali posti in opera e rappresenta una branca delle Scienze Geologiche e delle Scienze applicate ai Beni Culturali. Tale ricerca, regolata e normata secondo standard nazionali e internazionali, permette di ampliare l’esperienza scientifica e culturale. I materiali lapidei, la cui scelta d’impiego fu ed è tutt’oggi tutt’altro che casuale, rappresentano parte della storia e ne rappresentano il patrimonio tangibil

A re-analysis of the NuSTAR and XMM-Newton broad-band spectrum of Ser~X-1

Context: Ser X-1 is a well studied LMXB which clearly shows a broad iron line. Recently, Miller et al. (2103) have presented broad-band, high quality NuSTAR data of SerX-1.Using relativistically smeared self-consistent reflection models, they find a value of R_in close to 1.0 R_ISCO (corresponding to 6 R_g), and a low inclination angle, less than 10 deg. Aims: The aim of this paper is to probe to what extent the choice of reflection and continuum models (and uncertainties therein) can affect the conclusions about the disk parameters inferred from the reflection component. To this aim we re-analyze all the available public NuSTAR and XMM-Newton. Ser X-1 is a well studied source, its spectrum has been observed by several instruments, and is therefore one of the best sources for this study. Methods: We use slightly different continuum and reflection models with respect to those adopted in literature for this source. In particular we fit the iron line and other reflection features with self-consistent reflection models as reflionx (with a power-law illuminating continuum modified with a high energy cutoff to mimic the shape of the incident Comptonization spectrum) and rfxconv. With these models we fit NuSTAR and XMM-Newton spectra yielding consistent spectral results. Results: Our results are in line with those already found by Miller et al. (2013) but less extreme. In particular, we find the inner disk radius at about 13 R_g and an inclination angle with respect to the line of sight of about 27 deg. We conclude that, while the choice of the reflection model has little impact on the disk parameters, as soon as a self-consistent model is used, the choice of the continuum model can be important in the precise determination of the disk parameters from the reflection component. Hence broad-band X-ray spectra are highly preferable to constrain the continuum and disk parameters.Comment: 13 pages including 8 figures. Accepted for publication in A&