Information theoretic approach to quantization and classification for signal processing, communications, and machine learning applications

There are five main contributions of this dissertation. The first contribution is new closed-form expressions for channel capacity of a new class of channel matrices. The second contribution is the discovery of the structure for optimal binary quantizer and the associated methods for finding an optimal quantizer that maximizes mutual information between the input and output for a given input distribution. The third contribution is the discovery of the structure for an optimal $K$-ary quantizer that maximizes the mutual information subject to an arbitrary constraint on the output distribution. The fourth contribution is the joint design of an optimal quantizer that maximizes the mutual information over both the input distribution and the quantization parameters for an arbitrary binary noisy channel with a given noise density. The last contribution is the development and analysis of novel efficient classification algorithms for finding the minimum impurity partition using mutual information as the metric

Effect of Dzyaloshinskii–Moriya interaction on Heisenberg antiferromagnetic spin chain in a longitudinal magnetic field

Using functional integral method for the Heisenberg antiferromagnetic spin chain with the added Dzyaloshinskii-Moriya Interaction in the presence of the longitudinal magnetic field, we find out expression for free energy of the spin chain via spin fluctuations, from which quantities characterize the antiferromagnetic order and phase transition such as staggered and total magnetizations derived. From that, we deduce the significant effect of the Dzyaloshinskii-Moriya interaction on the reduction of the antiferromagnetic order and show that the total magnetization can be deviated from the initial one under the influence of canting of the spins due to a combination of the Dzyaloshinskii-Moriya interaction and the magnetic field. Besides, the remarkable role of the transverse spin fluctuations due to the above factors on the antiferromagnetic behaviours of the spin chain is also indicated. &nbsp

Supercruiser Arrow HS-8

Technology in aeronautics has advanced dramatically since the last design of a production High Speed Civil Transport (HSCT) aircraft. Newly projected requirements call for a new High Speed Civil Transport aircraft with a range of approximately 550 nm and at least 275 passenger capacity. The aircraft must be affordable and marketable. The new HSCT must be able to sustain long-duration flights and to absorb the abuse of daily operation. The new aircraft must be safe and simple to fly and require a minimum amount of maintenance. This aircraft must meet FAA certification criteria of FAR Part 25 and environmental constraints. Several design configurations were examined and two designs were selected for further investigation. The first design employs the delta planform wings and conventional empennage layout. The other design uses a swing wing layout and conventional empennage. Other engineering challenges, including materials and propulsion are also discussed. At a cruise flight speed between Mach 2.2 and Mach 3.0, no current generation of materials can endure the thermal loading of supersonic flight and satisfy the stringent weight requirements. A new generation of lightweight composite materials must be developed for the HSCT. With the enforcement of stage 3 noise restrictions, these new engines must be able to propel the aircraft and satisfy the noise limit. The engine with the most promise is the variable cycle engine. At low subsonic speeds the engine operates like a turbofan engine, providing the most efficient performance. At higher speeds the variable cycle engine operates as a turbojet power plant. The two large engine manufacturers, General Electric and Pratt & Whitney in the United States, are combining forces to make the variable cycle engine a reality

Neurogenic Hypotension and Bradycardia Modulated by Electroacupuncture in Hypothalamic Paraventricular Nucleus

Electroacupuncture (EA) stimulates somatic median afferents underlying P5-6 acupoints and modulates parasympathoexcitatory reflex responses through central processing in the brainstem. Although decreases in blood pressure and heart rate by the neural-mediated Bezold-Jarisch reflex responses are modulated by EA through opioid actions in the nucleus tractus solitarius and nucleus ambiguus, the role of the hypothalamus is unclear. The hypothalamic paraventricular nucleus (PVN) is activated by sympathetic afferents and regulates sympathetic outflow and sympathoexcitatory cardiovascular responses. In addition, the PVN is activated by vagal afferents, but little is known about its regulation of cardiopulmonary inhibitory hemodynamic responses. We hypothesized that the PVN participates in the Bezold-Jarisch reflex responses and EA inhibits these cardiopulmonary responses through the PVN opioid system. Rats were anesthetized and ventilated, and their heart rate and blood pressures were monitored. Application of phenylbiguanide every 10 min close to the right atrium induced consistent depressor and bradycardia reflex responses. Unilateral microinjection of the depolarization blockade agent kainic acid or glutamate receptor antagonist kynurenic acid in the PVN reduced these reflex responses. In at least 70% of the rats, 30 min of bilateral EA at P5-6 acupoints reduced the depressor and bradycardia responses for at least 60 min. Blockade of the CCK-1 receptors converted the non-responders into EA-responders. Unilateral PVN-microinjection with naloxone reversed the EA inhibition. Vagal-evoked activity of the PVN cardiovascular neurons was reduced by 30 min EA (P5-6) through opioid receptor activation. These data indicate that PVN processes inhibitory cardiopulmonary reflexes and participates in EA-modulation of the neural-mediated vasodepression and bradycardia

Pichia pastoris versus Saccharomyces cerevisiae:a case study on the recombinant production of human granulocyte-macrophage colony-stimulating factor

BACKGROUND: Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) is a glycoprotein that has been approved by the FDA for the treatment of neutropenia and leukemia in combination with chemotherapies. Recombinant hGM-CSF is produced industrially using the baker's yeast, Saccharomyces cerevisiae, by large-scale fermentation. The methylotrophic yeast, Pichia pastoris, has emerged as an alternative host cell system due to its shorter and less immunogenic glycosylation pattern together with higher cell density growth and higher secreted protein yield than S. cerevisiae. In this study, we compared the pipeline from gene to recombinant protein in these two yeasts. RESULTS: Codon optimization in silico for both yeast species showed no difference in frequent codon usage. However, rhGM-CSF expressed from S. cerevisiae BY4742 showed a significant discrepancy in molecular weight from those of P. pastoris X33. Analysis showed purified rhGM-CSF species with molecular weights ranging from 30 to more than 60 kDa. Fed-batch fermentation over 72 h showed that rhGM-CSF was more highly secreted from P. pastoris than S. cerevisiae (285 and 64 mg total secreted protein/L, respectively). Ion exchange chromatography gave higher purity and recovery than hydrophobic interaction chromatography. Purified rhGM-CSF from P. pastoris was 327 times more potent than rhGM-CSF from S. cerevisiae in terms of proliferative stimulating capacity on the hGM-CSF-dependent cell line, TF-1. CONCLUSION: Our data support a view that the methylotrophic yeast P. pastoris is an effective recombinant host for heterologous rhGM-CSF production

Rapid decrease of malaria morbidity following the introduction of community-based monitoring in a rural area of central Vietnam

<p>Abstract</p> <p>Background</p> <p>Despite a successful control programme, malaria has not completely disappeared in Vietnam; it remains endemic in remote areas of central Vietnam, where standard control activities seem to be less effective. The evolution of malaria prevalence and incidence over two and half years in a rural area of central Vietnam, after the introduction of community-based monitoring of malaria cases, is presented.</p> <p>Methods</p> <p>After a complete census, six cross-sectional surveys and passive detection of malaria cases (by village and commune health workers using rapid diagnostic tests) were carried out between March 2004 and December 2006 in Ninh-Thuan province, in a population of about 10,000 individuals. The prevalence of malaria infection and the incidence of clinical cases were estimated.</p> <p>Results</p> <p>Malaria prevalence significantly decreased from 13.6% (281/2,068) in December 2004 to 4.0% (80/2,019) in December 2006. <it>Plasmodium falciparum </it>and <it>Plasmodium vivax </it>were the most common infections with few <it>Plasmodium malariae </it>mono-infections and some mixed infections. During the study period, malaria incidence decreased by more than 50%, from 25.7/1,000 population at risk in the second half of 2004 to 12.3/1,000 in the second half of 2006. The incidence showed seasonal variations, with a yearly peak between June and December, except in 2006 when the peak observed in the previous years did not occur.</p> <p>Conclusion</p> <p>Over a 2.5-year follow-up period, malaria prevalence and incidence decreased by more than 70% and 50%, respectively. Possibly, this could be attributed to the setting up of a passive case detection system based on village health workers, indicating that a major impact on the malaria burden can be obtained whenever prompt diagnosis and adequate treatment are available.</p

Discussing Depression with Vietnamese American Patients

Background Asian patients preferentially seek mental health care from their primary care providers but are unlikely to receive it. Primary care providers need culturally-informed strategies for addressing stigmatizing illnesses. Methods 11 Vietnamese American community members participated in semi-structured interviews. Interviews were audio-taped and transcribed. The grounded theory approach was used for qualitative coding and thematic analysis. Results Vietnamese community members describe experiences with depression under four themes: (1) Stigma and face; (2) Social functioning and the role of the family; (3) Traditional healing and beliefs about medications; and (4) Language and culture. Based on this data, we offer suggestions for improving culturally-informed care for Vietnamese Americans. Disucssion Our study adds to the research aimed at improving communication and health care relationships between physicians and Vietnamese American patients. Physicians should learn to tailor their interviewing style to the increasingly diverse patient population

The use of reproductive healthcare at commune health stations in a changing health system in Vietnam

Background: With health sector reform in Vietnam moving towards greater pluralism, commune health stations (CHSs) have been subject to growing competition from private health services and increasing numbers of patients bypassing CHSs for higher-level health facilities. This study describes the pattern of reproductive health (RH) and family planning (FP) service utilization among women at CHSs and other health facilities, and explores socio demographic determinants of RH service utilization at the CHS level

Australia: A Continent Without Native Powdery Mildews? The First Comprehensive Catalog Indicates Recent Introductions and Multiple Host Range Expansion Events, and Leads to the Re-discovery of Salmonomyces as a New Lineage of the Erysiphales

In contrast to Eurasia and North America, powdery mildews (Ascomycota, Erysiphales) are understudied in Australia. There are over 900 species known globally, with fewer than currently 60 recorded from Australia. Some of the Australian records are doubtful as the identifications were presumptive, being based on host plant-pathogen lists from overseas. The goal of this study was to provide the first comprehensive catalog of all powdery mildew species present in Australia. The project resulted in (i) an up-to-date list of all the taxa that have been identified in Australia based on published DNA barcode sequences prior to this study; (ii) the precise identification of 117 specimens freshly collected from across the country; and (iii) the precise identification of 30 herbarium specimens collected between 1975 and 2013. This study confirmed 42 species representing 10 genera, including two genera and 13 species recorded for the first time in Australia. In Eurasia and North America, the number of powdery mildew species is much higher. Phylogenetic analyses of powdery mildews collected from Acalypha spp. resulted in the transfer of Erysiphe acalyphae to Salmonomyces, a resurrected genus. Salmonomyces acalyphae comb. nov. represents a newly discovered lineage of the Erysiphales. Another taxonomic change is the transfer of Oidium ixodiae to Golovinomyces. Powdery mildew infections have been confirmed on 13 native Australian plant species in the genera Acacia, Acalypha, Cephalotus, Convolvulus, Eucalyptus, Hardenbergia, Ixodia, Jagera, Senecio, and Trema. Most of the causal agents were polyphagous species that infect many other host plants both overseas and in Australia. All powdery mildews infecting native plants in Australia were phylogenetically closely related to species known overseas. The data indicate that Australia is a continent without native powdery mildews, and most, if not all, species have been introduced since the European colonization of the continent

Perspectives on child diarrhoea management and health service use among ethnic minority caregivers in Vietnam

<p>Abstract</p> <p>Background</p> <p>In Vietnam, primary government health services are now accessible for the whole population including ethnic minority groups (EMGs) living in rural and mountainous areas. However, little is known about EMGs' own perspectives on illness treatment and use of health services. This study investigates treatment seeking strategies for child diarrhoea among ethnic minority caregivers in Northern Vietnam in order to suggest improvements to health services for EMGs and other vulnerable groups.</p> <p>Methods</p> <p>The study obtained qualitative data from eight months of field work among four EMGs in lowland and highland villages in the Northern Lao Cai province. Triangulation of methods included in-depth interviews with 43 caregivers of pre-school children (six years and below) who had a case of diarrhoea during the past month, three focus group discussions (FGDs) with men, and two weeks of observations at two Communal Health Stations (CHGs). Data was content-analyzed by ordering data into empirically and theoretically inspired themes and sub-categories assisted by the software NVivo8.</p> <p>Results</p> <p>This study identified several obstacles for EMG caregivers seeking health services, including: gender roles, long travelling distances for highland villagers, concerns about the indirect costs of treatment and a reluctance to use government health facilities due to feelings of being treated disrespectfully by health staff. However, ethnic minority caregivers all recognized the danger signs of child diarrhoea and actively sought simultaneous treatment in different health care systems and home-based care. Treatments were selected by matching the perceived cause and severity of the disease with the 'compatibility' of different treatments to the child.</p> <p>Conclusions</p> <p>In order to improve EMGs' use of government health services it is necessary to improve the communication skills of health staff and to acknowledge both EMGs' explanatory disease models and the significant socio-economic constraints they experience. Broader health promotion programs should address the significant gender roles preventing highland mothers from seeking health services and include family elders and fathers in future health promotion programs. Encouraging existing child health care practices, including continued breastfeeding during illness and the use of home-made rehydration solutions, also present important opportunities for future child health promotion.</p