PHASE ESTIMATION FOR SINGLE AND MULTI-CHANNEL SPEECH ENHANCEMENT IN MULTI SOURCE ENVIRONMENT

This letter presents a novel method to estimate the clean speech phase spectrum, given the noisy speech observation in single-channel speech enhancement. The proposed method relies on the phase decomposition of the instantaneous noisy phase spectrum followed by temporal smoothing in order to reduce the large variance of noisy phase, and consequently reconstructs an enhanced instantaneous phase spectrum for signal reconstruction. Multi channel systems utilize spatial diversity which is not present in single channel systems. Novel beam-forming based spatial spectrum estimation methods for multi channel speech enhancement have been proposed in this thesis. Under the fixed beam forming framework, a new reverberant speech enhancement method that utilizes the LP residual cepstrum is developed. On the other hand, a LCMV based spectral method is developed for joint noise cancellation and dereverberation in a beam-forming framework. This is realized as a multi channel LCMV filter that constrains both the early and late parts of the speech frame. The filter outputs are then beam formed to remove late reverberations. These methods indicate significant improvement in perceptual quality of separated signals and distant speech recognition performance when compared to conventional methods

Field-Dependent Tilt and Birefringence of Electroclinic Liquid Crystals: Theory and Experiment

An unresolved issue in the theory of liquid crystals is the molecular basis of the electroclinic effect in the smectic-A phase. Recent x-ray scattering experiments suggest that, in a class of siloxane-containing liquid crystals, an electric field changes a state of disordered molecular tilt in random directions into a state of ordered tilt in one direction. To investigate this issue, we measure the optical tilt and birefringence of these liquid crystals as functions of field and temperature, and we develop a theory for the distribution of molecular orientations under a field. Comparison of theory and experiment confirms that these materials have a disordered distribution of molecular tilt directions that is aligned by an electric field, giving a large electroclinic effect. It also shows that the net dipole moment of a correlated volume of molecules, a key parameter in the theory, scales as a power law near the smectic-A--smectic-C transition.Comment: 18 pages, including 9 postscript figures, uses REVTeX 3.0 and epsf.st

Theory of Cylindrical Tubules and Helical Ribbons of Chiral Lipid Membranes

We present a general theory for the equilibrium structure of cylindrical tubules and helical ribbons of chiral lipid membranes. This theory is based on a continuum elastic free energy that permits variations in the direction of molecular tilt and in the curvature of the membrane. The theory shows that the formation of tubules and helical ribbons is driven by the chirality of the membrane. Tubules have a first-order transition from a uniform state to a helically modulated state, with periodic stripes in the tilt direction and ripples in the curvature. Helical ribbons can be stable structures, or they can be unstable intermediate states in the formation of tubules.Comment: 43 pages, including 12 postscript figures, uses REVTeX 3.0 and epsf.st

Regular dendritic patterns induced by non-local time-periodic forcing

The dynamic response of dendritic solidification to spatially homogeneous time-periodic forcing has been studied. Phase-field calculations performed in two dimensions (2D) and experiments on thin (quasi 2D) liquid crystal layers show that the frequency of dendritic side-branching can be tuned by oscillatory pressure or heating. The sensitivity of this phenomenon to the relevant parameters, the frequency and amplitude of the modulation, the initial undercooling and the anisotropies of the interfacial free energy and molecule attachment kinetics, has been explored. It has been demonstrated that besides the side-branching mode synchronous with external forcing as emerging from the linear Wentzel-Kramers-Brillouin analysis, modes that oscillate with higher harmonic frequencies are also present with perceptible amplitudes.Comment: 15 pages, 23 figures, Submitted to Phys. Rev.

hERG1 channels drive tumour malignancy and may serve as prognostic factor in pancreatic ductal adenocarcinoma

BACKGROUND: hERG1 channels are aberrantly expressed in human cancers. The expression, functional role and clinical significance of hERG1 channels in pancreatic ductal adenocarcinoma (PDAC) is lacking. METHODS: hERG1 expression was tested in PDAC primary samples assembled as tissue microarray by immunohistochemistry using an anti-hERG1 monoclonal antibody (α-hERG1-MoAb). The functional role of hERG1 was studied in PDAC cell lines and primary cultures. ERG1 expression during PDAC progression was studied in Pdx-1-Cre,LSL-Kras(G12D/+),LSL-Trp53(R175H/+) transgenic (KPC) mice. ERG1 expression in vivo was determined by optical imaging using Alexa-680-labelled α-hERG1-MoAb. RESULTS: (i) hERG1 was expressed at high levels in 59% of primary PDAC; (ii) hERG1 blockade decreased PDAC cell growth and migration; (iii) hERG1 was physically and functionally linked to the Epidermal Growth Factor-Receptor pathway; (iv) in transgenic mice, ERG1 was expressed in PanIN lesions, reaching high expression levels in PDAC; (v) PDAC patients whose primary tumour showed high hERG1 expression had a worse prognosis; (vi) the α-hERG1-MoAb could detect PDAC in vivo. CONCLUSIONS: hERG1 regulates PDAC malignancy and its expression, once validated in a larger cohort also comprising of late-stage, non-surgically resected cases, may be exploited for diagnostic and prognostic purposes in PDAC either ex vivo or in vivo

Management of Portal Hypertension in Children

Management of portal hypertension in children has evolved over the past several decades. Portal hypertension can result from intrahepatic or extrahepatic causes. Management should be tailored to the child based on the etiology of the portal hypertension and on the functionality of the liver. The most serious complication of portal hypertension is gastroesophageal variceal bleeding, which has a mortality of up to 30%. Initial treatment of bleeding focuses on stabilizing the patient. Further treatment measures may include endoscopic, medical, or surgical interventions as appropriate for the child, depending on the cause of the portal hypertension. β-Blockers have not been proven to effectively prevent primary or secondary variceal bleeding in children. Sclerotherapy and variceal band ligation can be used to stop active bleeding and can prevent bleeding from occurring. Transjugular intrahepatic portosystemic shunts and surgical shunts may be reserved for those who are not candidates for transplant or have refractory bleeding despite medical or endoscopic treatment

The Multidimensional Livelihood Vulnerability Index – an instrument to measure livelihood vulnerability to change in the Hindu Kush Himalayas

In recent years the population of the Hindu Kush Himalayas (HKH) has been confronted with rapid social, economic, demographic, and political changes. In addition, the region is particularly vulnerable to climate change. However, there is a scarcity of cohesive information on the state of the environment and on the socio-economic situation of the approximately 210 million people who reside in the HKH. Specifically, data on livelihood vulnerability are lacking. As part of the Himalaya Climate Change Adaptation Programme, the International Centre for Integrated Mountain Development, in consultation with regional and international partners, has developed the Multidimensional Livelihood Vulnerability Index (MLVI), a measure to explore and describe livelihood vulnerability to climatic, environmental, and socio-economic change in the HKH region. This paper documents how the MLVI was developed and demonstrates the utility of this approach by using primary household survey data of 16 selected districts of three sub-basins in the HKH region. The analysis gives important clues about differences in the intensity and composition of multidimensional livelihood vulnerability across these locations that should be useful to decision makers to identify areas of intervention and guide their measures to reduce vulnerability

Community Engagement for Birth Preparedness and Complication Readiness in the Community Level Interventions for Pre-eclampsia (CLIP) Trial in India: A Mixed-Method Evaluation

Objective: To describe the process of community engagement (CE) in northern Karnataka, India and its impact on pre-eclampsia knowledge, birth preparedness and complication readiness, pregnancy-related care seeking and maternal morbidity. Design: This study was a secondary analysis of a cluster randomised trial of Community Level Interventions for Pre-eclampsia (CLIP). A total of 12 clusters based on primary health centre catchment areas were randomised to intervention or control. CE was conducted in intervention clusters. CE attendance was summarised according to participant group using both quantitative and qualitative assessment. Pre-eclampsia knowledge, birth preparedness, health services engagement and perinatal outcomes was evaluated within trial surveillance. Outcomes were compared between trial arms using a mixed effects logistic regression model on RStudio (RStudio, Boston, USA). Community feedback notes were thematically analysed on NVivo V.12 (QSR International, Melbourne, Australia). Setting: Belagavi and Bagalkote districts in rural Karnataka, India. Participants: Pregnant women and women of reproductive age, mothers and mothers-in-law, community stakeholders and male household decision-makers and health workers. Results: A total of 1379 CE meetings were conducted with 39 362 participants between November 2014 and October 2016. CE activities may have had an effect on modifying community attitudes towards hypertension in pregnancy and its complications. However, rates of pre-eclampsia knowledge, birth preparedness, health services engagement and maternal morbidities among individual pregnant women were not significantly impacted by CE activities in their area. Conclusion: Evaluation of our CE programme in India demonstrates the feasibility of reaching pregnant women alongside household decision-makers, community stakeholders and health workers. More research is needed to explore the pathways of impact between broad community mobilisation to strengthen support for maternal care seeking and clinical outcomes of individual pregnant women. Trial registration number: NCT01911494

Environmental Response and Genomic Regions Correlated with Rice Root Growth and Yield under Drought in the OryzaSNP Panel across Multiple Study Systems

The rapid progress in rice genotyping must be matched by advances in phenotyping. A better understanding of genetic variation in rice for drought response, root traits, and practical methods for studying them are needed. In this study, the OryzaSNP set (20 diverse genotypes that have been genotyped for SNP markers) was phenotyped in a range of field and container studies to study the diversity of rice root growth and response to drought. Of the root traits measured across more than 20 root experiments, root dry weight showed the most stable genotypic performance across studies. The environment (E) component had the strongest effect on yield and root traits. We identified genomic regions correlated with root dry weight, percent deep roots, maximum root depth, and grain yield based on a correlation analysis with the phenotypes and aus, indica, or japonica introgression regions using the SNP data. Two genomic regions were identified as hot spots in which root traits and grain yield were co-located; on chromosome 1 (39.7–40.7 Mb) and on chromosome 8 (20.3–21.9 Mb). Across experiments, the soil type/ growth medium showed more correlations with plant growth than the container dimensions. Although the correlations among studies and genetic co-location of root traits from a range of study systems points to their potential utility to represent responses in field studies, the best correlations were observed when the two setups had some similar properties. Due to the co-location of the identified genomic regions (from introgression block analysis) with QTL for a number of previously reported root and drought traits, these regions are good candidates for detailed characterization to contribute to understanding rice improvement for response to drought. This study also highlights the utility of characterizing a small set of 20 genotypes for root growth, drought response, and related genomic regions

Geographic EBV variants confound disease-specific variant interpretation and predict variable immune therapy responses

Epstein-Barr virus (EBV) is a potent carcinogen linked to hematologic and solid malignancies and causes significant global morbidity and mortality. Therapy using allogeneic EBV-specific lymphocytes shows promise in certain populations, but the impact of EBV genome variation on these strategies remains unexplored. To address this, we sequenced 217 EBV genomes, including hematologic malignancies from Guatemala, Peru, Malawi, and Taiwan, and analyzed them alongside 1307 publicly available EBV genomes from cancer, nonmalignant diseases, and healthy individuals across Africa, Asia, Europe, North America, and South America. These included, to our knowledge, the first natural killer (NK)/T-cell lymphoma (NKTCL) EBV genomes reported outside of East Asia. Our findings indicate that previously proposed EBV genome variants specific to certain cancer types are more closely tied to geographic origin than to cancer histology. This included variants previously reported to be specific to NKTCL but were prevalent in EBV genomes from other cancer types and healthy individuals in East Asia. After controlling for geographic region, we did identify multiple NKTCL-specific variants associated with a 7.8-fold to 21.9-fold increased risk. We also observed frequent variations in EBV genomes that affected peptide sequences previously reported to bind common major histocompatibility complex alleles. Finally, we found several nonsynonymous variants spanning the coding sequences of current vaccine targets BALF4, BKRF2, BLLF1, BXLF2, BZLF1, and BZLF2. These results highlight the need to consider geographic variation in EBV genomes when devising strategies for exploiting adaptive immune responses against EBV-related cancers, ensuring greater global effectiveness and equity in prevention and treatment