Hierarchy of integrable Hamiltonians describing of nonlinear n-wave interaction

In the paper we construct an hierarchy of integrable Hamiltonian systems which describe the variation of n-wave envelopes in nonlinear dielectric medium. The exact solutions for some special Hamiltonians are given in terms of elliptic functions of the first kind.Comment: 17 page

The role of the Fulbe in the urban life and economy of Lunsar, Sierra Leone: being a study of the adaptation of an immigrant group

In 1954 Dr. J. Littlejohn conducted a pilot survey of the town of Lunsar in Sierra Leone on behalf of the Department of Social Anthropology in the University of Edinburgh. Five years later, in May 1959 under the direction of Dr. K. L. Little, Dr. Littlejohn returned to Sierra Leone as leader of the University of Edinburgh, Lunsar Research Team. The other two team members at that time were Dr. D. Gamble (anthropologist) and Dr. R. Mills (physician). This team, generous- ly financed by the Nuffield Foundation, had the aim of studying the process of urbanisation in a town which had grown solely as a result of open cast iron mining activities taking place less than a mile away. During the course of his investi- gations Dr. Littlejohn reported that one tribal group, the Fula or Fulbe, were different from the other immigrants in that they kept separate from the other tribes, appeared to be strongly Muslim, and had defeated the Temne on a number of occasions in Historical times. It was recommended that I go to Lunsar and study the Fulbe to find out how they adapted themselves to living in Lunsar so that the Fulbe might be compared with the other tribal groups. An outline of techniques used in the study of the Fulbe is given below. Participant observation. This in itself is more of a way of life than a special technique, a kind of omnidirectional departure point from which the field worker gathers information by a number of means, viz: - a. observation and noting of the physical distribution and movement of the subjects of study. b. the interception by ear and eye of distribution and content of communications between subjects. c. the asking of direct and indirect questions to elucidate what has been seen or heard, or read as being the behaviour of the subjects. The taking up of a special identity, the effort of learning the language, the assumption of a local name, the sharing of food when offered and the other deli- berate acts of behaviour already mentioned are in fact 'participant observations' which are unstructured and can themselves only lead to impressions based on chance contacts. The study period in Lunsar was originally to be six months, although this was later extended to ten months. Clearly, to collect enough data within this time a very intensive study had to be conducted. Selection of informants. Since there were so few Fulbe in Lunsar it was important to obtain certain basic data on all the residents and as many Fulbe passing through Lunsar as possible. To assist in this an interview guide was drawn up which appears as an Appendix. From information gained in this way the demography and statistical structure of Lunsar and itinerant Fulbe was calculated. In analysis, all Fulbe who had stayed in Lunsar longer than nine months were treated as residents, and those staying for a shorter period were regarded as itinerants. This is a purely arbitrary division but no other could be adopted because of the unpredictability and high mobility of the Fulbe. Additional specialist information, for example on occupations, ritual and vi. family was obtained directly from the persons best able to provide the informa- tion. An attempt was made to avoid using one informant more than others. Pachometric Tests. The psychometric tests used were not intended to be anything more than a more exact way of verifying or refuting hypothesesmade on the basis of data obtained by observation and interview. Where the data from such tests appears in the text only a minimum of arithmetic appears, and the main calcula- tions appear separately in an appendix. Samples. The informants subjected to tests of one kind or another were not all selected at random. Although random samples may be ideal, especially when the distribution of variations in the population is known, they were found to be un- satisfactory because of the informant's' continuous coming and going as they went about their business, trailing, etc. Also, even if the population in Lunsar had been correctly represented, the total statistical universe of Fulbe all over Africa could not be. To get round this difficulty large samples were used (3 plus) stratified by age and occupation in as similar manner as possible as the total Lunsar Fulbe population. Also appearing as an appendix is a list of Fulbe informants in Lunsar and the tests set them. It will be noted that few women have been used in these special studies. This is because the Fulbe women although very independent are not considered by their menfolk as repositories of knowledge and wisdom. The women themselves act according to their society's expectations of them and consider intensive question- ing on topics other than domestic issues embarrassing and answer such questions by "mi anda" - I do not know. Documentary material. Although there is an enormous literature on the Fulbe, most of it takes its subject matter from areas dominated by Fulbe. Little has been written about the behaviour of Fulbe on the peripheries of these concentra- reemburs oÇ tions, where they are faced with the problem of interacting with ,(other cultures ulture, while maintaining their own c vii. A few articles on Fulbe in Sierra Leone have been written and where possible the relevant material has been incorporated in this study. Native Authority court records were consulted, although they reported few cases involving Fulbe. A far richer source of information way, the District Commissioner's files at Port Lokko, from which the history of political conflict since the war between Fulbe and the Temnes and Lokkos was in part obtained. Mechanical E uioment, a. A camera was used to obtain pictorial illustrations, some it of which appear in the text. However, it was found that /was very difficult to com- bine note taking and picture taking, so most photographs were taken on outings specifically assigned for this purpose. It was found that the best technique was to write down a list of the photographs required and systematically tick off each subject as it was photographed. when the social situation to be studied is out- side the control of the field worker, e.g. rituals, a decision has to be made at the time on whether notes or photographs will be of most use. When long sequen- ces of photographs can be taken and the films processed locally it is fairly easy to ask informants to explain them afterwards. b. A tape recorder was used to collect material at cere- monies, although for various reasons it did not work on some important occasions. The tape recorder was sometimes used during interviews when more than one informant was being used. This enabled me to find out afterwards what was discussed by people not actually talking to me at the time. c. General information on each informant was transferred on to 'Cope. Chat Paramount Punch Cards' to assist in the processing of statistical data. Each informant was given a code number on being first interviewed. This helped me to differentiate between a number of people with the same names. Each individuals card could also be sorted out by the code number. A complete descrip- tion of the card system and codes appearsin appendix D. This was written in the field so that in the event of an accident to myself, the material would be understandable to anyone else

Using Wave-Packet Interferometry to Monitor the External Vibrational Control of Electronic Excitation Transfer

We investigate the control of electronic energy transfer in molecular dimers through the preparation of specific vibrational coherences prior to electronic excitation, and its observation by nonlinear wave-packet interferometry. Laser-driven coherent nuclear motion can affect the instantaneous resonance between site-excited electronic states and thereby influence short-time electronic excitation transfer (EET). We first illustrate this control mechanism with calculations on a dimer whose constituent monomers undergo harmonic vibrations. We then consider the use of nonlinear wave-packet interferometry (nl-WPI) experiments to monitor the nuclear dynamics accompanying EET in general dimer complexes following impulsive vibrational excitation by a sub-resonant control pulse (or control pulse sequence). In measurements of this kind, two pairs of polarized phase-related femtosecond pulses following the control pulse generate superpositions of coherent nuclear wave packets in optically accessible electronic states. Interference contributions to the time- and frequency-integrated fluorescence signal due to overlaps among the superposed wave packets provide amplitude-level information on the nuclear and electronic dynamics. We derive the basic expression for a control-pulse-dependent nl-WPI signal. The electronic transition moments of the constituent monomers are assumed to have a fixed relative orientation, while the overall orientation of the complex is distributed isotropically. We include the limiting case of coincident arrival by pulses within each phase-related pair in which control-influenced nl-WPI reduces to a fluorescence-detected pump-probe difference experiment. Numerical calculations of pump-probe signals based on these theoretical expressions are presented in the following paper

Microarray analysis of whole genome expression of intracellular Mycobacterium tuberculosis

Analysis of the changing mRNA expression profile of Mycobacterium tuberculosis though the course of infection promises to advance our understanding of how mycobacteria are able to survive the host immune response. The difficulties of sample extraction from distinct mycobacterial populations, and of measuring mRNA expression profiles of multiple genes has limited the impact of gene expression studies on our interpretation of this dynamic infection process. The development of whole genome microarray technology together with advances in sample collection have allowed the expression pattern of the whole M. tuberculosis genome to be compared across a number of different in vitro conditions, murine and human tissue culture models and in vivo infection samples. This review attempts to produce a summative model of the M. tuberculosis response to infection derived from or reflected in these gene expression datasets. The mycobacterial response to the intracellular environment is characterised by the utilisation of lipids as a carbon source and the switch from aerobic/microaerophilic to anaerobic respiratory pathways. Other genes induced in the macrophage phagosome include those likely to be involved in the maintenance of the cell wall and genes related to DNA damage, heat shock, iron sequestration and nutrient limitation. The comparison of transcriptional data from in vitro models of infection with complex in vivo samples, together with the use of bacterial RNA amplification strategies to sample defined populations of bacilli, should allow us to make conclusions about M. tuberculosis physiology and host microenvironments during natural infection

Breaking of the overall permutation symmetry in nonlinear optical susceptibilities of one-dimensional periodic dimerized Huckel model

Based on infinite one-dimensional single-electron periodic models of trans-polyacetylene, we show analytically that the overall permutation symmetry of nonlinear optical susceptibilities is, albeit preserved in the molecular systems with only bound states, no longer generally held for the periodic systems. The overall permutation symmetry breakdown provides a fairly natural explanation to the widely observed large deviations of Kleinman symmetry for periodic systems in off-resonant regions. Physical conditions to experimentally test the overall permutation symmetry break are discussed.Comment: 7 pages, 1 figur

Hawking radiation from "phase horizons" in laser filaments?

Belgiorno et al have reported on experiments aiming at the detection of (the analogue of) Hawking radiation using laser filaments [F. Belgiorno et al, Phys. Rev. Lett. 105, 203901 (2010)]. They sent intense focused Bessel pulses into a non-linear dielectric medium in order to change its refractive index via the Kerr effect and saw creation of photons orthogonal to the direction of travel of the pluses. Since the refractive index change in the pulse generated a "phase horizon" (where the phase velocity of these photons equals the pulse speed), they concluded that they observed the analogue of Hawking radiation. We study this scenario in a model with a phase horizon and a phase velocity very similar to that of their experiment and find that the effective metric does not quite correspond to a black hole. The photons created in this model are not due to the analogue of black hole evaporation but have more similarities to cosmological particle creation. Nevertheless, even this effect cannot explain the observations -- unless the pulse has significant small scale structure in both the longitudinal and transverse dimensions.Comment: 13 pages RevTeX, 2 figure

Linear response functions for a vibrational configuration interaction state

Linear response functions are implemented for a vibrational configuration interaction state allowing accurate analytical calculations of pure vibrational contributions to dynamical polarizabilities. Sample calculations are presented for the pure vibrational contributions to the polarizabilities of water and formaldehyde. We discuss the convergence of the results with respect to various details of the vibrational wave function description as well as the potential and property surfaces. We also analyze the frequency dependence of the linear response function and the effect of accounting phenomenologically for the finite lifetime of the excited vibrational states. Finally, we compare the analytical response approach to a sum-over-states approac

On the Non-invasive Measurement of the Intrinsic Quantum Hall Effect

With a model calculation, we demonstrate that a non-invasive measurement of intrinsic quantum Hall effect defined by the local chemical potential in a ballistic quantum wire can be achieved with the aid of a pair of voltage leads which are separated by potential barriers from the wire. B\"uttiker's formula is used to determine the chemical potential being measured and is shown to reduce exactly to the local chemical potential in the limit of strong potential confinement in the voltage leads. Conditions for quantisation of Hall resistance and measuring local chemical potential are given.Comment: 16 pages LaTex, 2 post-script figures available on reques

Unsupervised machine learning of integrated health and social care data from the Macmillan Improving the Cancer Journey service in Glasgow

Background: Improving the Cancer Journey (ICJ) was launched in 2014 by Glasgow City Council and Macmillan Cancer Support. As part of routine service, data is collected on ICJ users including demographic and health information, results from holistic needs assessments and quality of life scores as measured by EQ-5D health status. There is also data on the number and type of referrals made and feedback from users on the overall service. By applying artificial intelligence and interactive visualization technologies to this data, we seek to improve service provision and optimize resource allocation.Method: An unsupervised machine-learning algorithm was deployed to cluster the data. The classical k-means algorithm was extended with the k-modes technique for categorical data, and the gap heuristic automatically identified the number of clusters. The resulting clusters are used to summarize complex data sets and produce three-dimensional visualizations of the data landscape. Furthermore, the traits of new ICJ clients are predicted by approximately matching their details to the nearest existing cluster center.Results: Cross-validation showed the model’s effectiveness over a wide range of traits. For example, the model can predict marital status, employment status and housing type with an accuracy between 2.4 to 4.8 times greater than random selection. One of the most interesting preliminary findings is that area deprivation (measured through Scottish Index of Multiple Deprivation-SIMD) is a better predictor of an ICJ client’s needs than primary diagnosis (cancer type).Conclusion: A key strength of this system is its ability to rapidly ingest new data on its own and derive new predictions from those data. This means the model can guide service provision by forecasting demand based on actual or hypothesized data. The aim is to provide intelligent person-centered recommendations. The machine-learning model described here is part of a prototype software tool currently under development for use by the cancer support community.Disclosure: Funded by Macmillan Cancer Support</p

Dissipative Tunneling in 2 DEG: Effect of Magnetic Field, Impurity and Temperature

We have studied the transport process in the two dimensional electron gas (2DEG) in presence of a magnetic field and a dissipative environment at temperature T. By means of imaginary time series functional integral method we calculate the decay rates at finite temperature and in the presence of dissipation. We have studied decay rates for wide range of temperatures -- from the thermally activated region to very low temperature region where the system decays by quantum tunneling. We have shown that dissipation and impurity helps the tunneling. We have also shown that tunneling is strongly affected by the magnetic field. We have demonstrated analytical results for all the cases mentioned above.Comment: 8 pages, 2 figure