The Source Size Dependence on the M_hadron Applying Fermi and Bose Statistics and I-Spin Invariance

The emission volume sizes of pions and Kaons, r_{\pi^\pm \pi^\pm} and r_{K^\pm K^\pm}, measured in the hadronic Z^0 decays via the Bose-Einstein Correlations (BEC), and the recent measurements of r_{\Lambda\Lambda} obtained by through the Pauli exclusion principle are used to study the r dependence on the hadron mass. A clear r_{\pi^\pm \pi^\pm} > r_{K^\pm K^\pm} > r_{\Lambda \Lambda} hierarchy is observed which seems to disagree with the basic string (LUND) model expectation. An adequate description of r(m) is obtained via the Heisenberg uncertainty relations and also by Local Parton Hadron Duality approach using a general QCD potential. These lead to a relation of the type r(m) ~ Constant/sqrt{m}. The present lack of knowledge on the f_o(980) decay rate to the K^0\bar{K}^0 channel prohibits the use of the r_{K^0_SK^0_S} in the r(m) analysis. The use of a generalised BEC and I-spin invariance, which predicts an BEC enhancement also in the K^{\pm}K^0 and \pi^{\pm}\pi^0 systems, should in the future help to include the r_{K^0_SK^0_S} in the r(m) analysis.Comment: 7 pages, 4 figures, Based on an invited talk given by G. Alexander at the XXIX Int. Symp. on Multiparticle Dynamics, 9-13 August 1999, Providence RI, USA. (to be published in the proceedings of this conference

Noise Reduction with Microphone Arrays for Speaker Identification

The presence of acoustic noise in audio recordings is an ongoing issue that plagues many applications. This ambient background noise is difficult to reduce due to its unpredictable nature. Many single channel noise reduction techniques exist but are limited in that they may distort the desired speech signal due to overlapping spectral content of the speech and noise. It is therefore of interest to investigate the use of multichannel noise reduction algorithms to further attenuate noise while attempting to preserve the speech signal of interest. Specifically, this thesis looks to investigate the use of microphone arrays in conjunction with multichannel noise reduction algorithms to aid aiding in speaker identification. Recording a speaker in the presence of acoustic background noise ultimately limits the performance and confidence of speaker identification algorithms. In situations where it is impossible to control the noise environment where the speech sample is taken, noise reduction algorithms must be developed and applied to clean the speech signal in order to give speaker identification software a chance at a positive identification. Due to the limitations of single channel techniques, it is of interest to see if spatial information provided by microphone arrays can be exploited to aid in speaker identification. This thesis provides an exploration of several time domain multichannel noise reduction techniques including delay sum beamforming, multi-channel Wiener filtering, and Spatial-Temporal Prediction filtering. Each algorithm is prototyped and filter performance is evaluated using various simulations and experiments. A three-dimensional noise model is developed to simulate and compare the performance of the above methods and experimental results of three data collections are presented and analyzed. The algorithms are compared and recommendations are given for the use of each technique. Finally, ideas for future work are discussed to improve performance and implementation of these multichannel algorithms. Possible applications for this technology include audio surveillance, identity verification, video chatting, conference calling and sound source localization

Effect of hyperemesis gravidarum on child neurodevelopment

BackgroundPregnancy outcome following hyperemesis gravidarum (HG) has been sparsely reported. This review article aims at critically reviewing the first prospective study of foetal long-term neurodevelopment after maternal HG.AimsThis review aimed at critically appraising the first prospective human study that aimed at investigating long term child neurodevelopment after exposure to maternal HG.MethodsIn this study, women with nausea and vomiting of pregnancy treated with doxylamine–pyridoxine (Diclectin) or with no pharmacotherapy were prospectively recruited. Their children (ages 3 6/12 to 6 11/12 years) were assessed for development using standardized psychological tests. The study cohort was divided into 2 groups: 1) severe NVP necessitating hospitalization of the woman for rehydration and electrolyte corrections (n=22) and 2) all other cases of nausea and vomiting of pregnancy (n=197). ResultsChildren of hospitalized mothers achieved significantly lower IQ scores than the rest of the children on verbal, performance and full scale IQ. In multivariable linear regression duration of hospitalization, maternal depression and maternal IQ were significant predictors for these outcomes. ConclusionThis first prospective human study documented that HG is associated with an increased risk for lower cognitive outcome among HG- exposed offspring. More research is needed to examine whether early use of anti-emetics may prevent hospitalization, leading to favourable child neurodevelopment

Identity and opportunity: The implications of using local languages in the primary education system of the Southern Nations, Nationalities and Peoples Region (SNNPR), Ethiopia.

The thesis concerns the reactions of groups of people to the introduction of local languages into the primary education system in Ethiopia. The changing patterns of language use in education come in response to the language policies of the Federal Democratic Government of Ethiopia, which were first introduced in 1991. The geographical area under consideration is the Southern Nations, Nationalities and Peoples Region (SNNPR). Eight local languages, spoken by the most populous groups of people in the region, are now in use in the primary education system. Some areas of the region have, however, continued to use Amharic, the national language, in primary schools. The field-work discusses the patterns of language use in education, and attitudes towards language use, in areas where local languages have been introduced, and those where Amharic is used. The thesis considers the wider implications of the reform for the peoples of the SNNPR, and, in furtherance of this objective, an attempt is made to place the reform in its historical context. That historical context includes the development of government language policy and the historical patterns of language use in the Ethiopian state, as well as the history of the peoples of the south-west of the country. The reform raises questions which concern identity and opportunity, for the peoples of the south-west of Ethiopia, considered as whole units, and for the individuals who belong to these groups of people. The reform also has profound implications for the status of these groups of people in the Ethiopian state. Opinions about the implications of this reform vary considerably, and the questions addressed by the field-work are a subject of importance in current political debate in Ethiopia

Sensitivity analysis of optimal operation of irrigation supply systems with water quality considerations

Abstract. A model for optimal operation of water supply/irrigation systems of various water quality sources, with treatment plants, multiple water quality conservative factors, and dilution junctions is presented. The objective function includes water cost at the sources, water conveyance costs which account for the hydraulics of the network indirectly, water treatment cost, and yield reduction costs of irrigated crops due to irrigation with poor quality water. The model can be used for systems with supply by canals as well as pipes, which serve both drinking water demands of urban/rural consumers and field irrigation requirements. The general nonlinear optimization problem has been simplified by decomposing it to a problem with linear constraints and nonlinear objective function. This problem is solved using the projected gradient method. The method is demonstrated for a regional water supply system in southern Israel that contains 39 pipes, 37 nodes, 11 sources, 10 agricultural consumers, and 4 domestic consumers. The optimal operation solution is described by discharge and salinity values for all pipes of the network. Sensitivity of the optimal solution to changes in the parameters is examined. The solution was found to be sensitive to the upper limit on drinking water quality, with total cost being reduced by 5% as the upper limit increases from 260 to 600 mg Cl l −1 . The effect of income from unit crop yield is more pronounced. An increase of income by a factor of 20 results in an increase of the total cost by a factor of 3, thus encouraging more use of fresh water as long as the marginal cost of water supply is smaller than the marginal decrease in yield loss. The effect of conveyance cost becomes more pronounced as its cost increases. An increase by a factor of 100 results in an increase of the total cost by about 14%. The network studied has a long pipe that connects two distinct parts of the network and permits the supply of fresh water from one part to the other. Increasing the maximum permitted discharge in this pipe from 0 to 200 m 3 h −1 reduces the total cost by 11%. Increasing the maximum discharge at one of the sources from 90 to 300 m 3 h −1 reduces the total cost by about 8%