Paraunitary oversampled filter bank design for channel coding

Oversampled filter banks (OSFBs) have been considered for channel coding, since their redundancy can be utilised to permit the detection and correction of channel errors. In this paper, we propose an OSFB-based channel coder for a correlated additive Gaussian noise channel, of which the noise covariance matrix is assumed to be known. Based on a suitable factorisation of this matrix, we develop a design for the decoder's synthesis filter bank in order to minimise the noise power in the decoded signal, subject to admitting perfect reconstruction through paraunitarity of the filter bank. We demonstrate that this approach can lead to a significant reduction of the noise interference by exploiting both the correlation of the channel and the redundancy of the filter banks. Simulation results providing some insight into these mechanisms are provided

Health education and the control of urogenital schistosomiasis: assessing the impact of the Juma na Kichocho comic-strip medical booklet in Zanzibar

Endeavours to control urogenital schistosomiasis on Unguja Island (Zanzibar) have focused on school-aged children. To assess the impact of an associated health education campaign, the supervised use of the comic-strip medical booklet Juma na Kichocho by Class V pupils attending eighteen primary schools was investigated. A validated knowledge and attitudes questionnaire was completed at baseline and repeated one year later following the regular use of the booklet during the calendar year. A scoring system (ranging from 0.0 to 5.0) measured children's understandings of schistosomiasis and malaria, with the latter being a neutral comparator against specific changes for schistosomiasis. In 2006, the average score from 751 children (328 boys and 423 girls) was 2.39 for schistosomiasis and 3.03 for malaria. One year later, the score was 2.43 for schistosomiasis and 2.70 for malaria from 779 children (351 boys and 428 girls). As might be expected, knowledge and attitudes scores for schistosomiasis increased (+0.05), but not as much as originally hoped, while the score for malaria decreased (-0.33). According to a Kolmogorov-Smirnov test, neither change was statistically significant. Analysis also revealed that 75% of school children misunderstood the importance of reinfection after treatment with praziquantel. These results are disappointing. They demonstrate that it is mistaken to assume that knowledge conveyed in child-friendly booklets will necessarily be interpreted, and acted upon, in the way intended. If long-term sustained behavioural change is to be achieved, health education materials need to engage more closely with local understandings and responses to urogenital schistosomiasis. This, in turn, needs to be part of the development of a more holistic, biosocial approach to the control of schistosomiasis

Electric transport properties of single-walled carbon nanotubes functionalized by plasma ion irradiation method

科研費報告書収録論文(課題番号:13852016/研究代表者:畠山力三/プラズマイオン照射による新機能性進化ナノチューブ創製法の開発

A New Evolutionary Path to Type Ia Supernovae: Helium-Rich Super-Soft X-Ray Source Channel

We have found a new evolutionary path to Type Ia supernovae (SNe Ia) which has been overlooked in previous work. In this scenario, a carbon-oxygen white dwarf (C+O WD) is originated, not from an asymptotic giant branch star with a C+O core, but from a red-giant star with a helium core of $\sim 0.8-2.0 M_\odot$. The helium star, which is formed after the first common envelope evolution, evolves to form a C+O WD of $\sim 0.8-1.1 M_\odot$ with transferring a part of the helium envelope onto the secondary main-sequence star. This new evolutionary path, together with the optically thick wind from mass-accreting white dwarf, provides a much wider channel to SNe Ia than previous scenarios. A part of the progenitor systems are identified as the luminous supersoft X-ray sources or the recurrent novae like U Sco, which are characterized by the accretion of helium-rich matter. The white dwarf accretes hydrogen-rich, helium-enhanced matter from a lobe-filling, slightly evolved companion at a critical rate and blows excess matter in the wind. The white dwarf grows in mass to the Chandrasekhar mass limit and explodes as an SN Ia. A theoretical estimate indicates that this channel contributes a considerable part of the inferred rate of SNe Ia in our Galaxy, i.e., the rate is about ten times larger than the previous theoretical estimates for white dwarfs with slightly evolved companions.Comment: 19 pages including 12 figures, to be published in ApJ, 519, No.

Functionalization of different polymers with sulfonic groups as a way to coat them with a biomimetic apatite layer

Covalent coupling of sulfonic group (–SO3H) was attempted on different polymers to evaluate efficacy of this functional group in inducing nucleation of apatite in body environment, and thereupon to design a simple biomimetic process for preparing bonelike apatite-polymer composites. Substrates of polyethylene terephthalate (PET), polycaprolactam (Nylon 6), high molecular weight polyethylene (HMWPE) and ethylene-vinyl alcohol copolymer (EVOH) were subjected to sulfonation by being soaked in sulfuric acid (H2SO4) or chlorosulfonic acid (ClSO3H) with different concentrations. In order to incorporate calcium ions, the sulfonated substrates were soaked in saturated solution of calcium hydroxide (Ca(OH)2). The treated substrates were soaked in a simulated body fluid (SBF). Fourier transformed infrared spectroscopy, thin-film X-ray diffraction, and scanning electron microscopy showed that the sulfonation and subsequent Ca(OH)2 treatments allowed formation of –SO3H groups binding Ca2+ ions on the surface of HMWPE and EVOH, but not on PET and Nylon 6. The HMWPE and EVOH could thus form bonelike apatite layer on their surfaces in SBF within 7 d. These results indicate that the –SO3H groups are effective for inducing apatite nucleation, and thereby that surface sulfonation of polymers are effective pre-treatment method for preparing biomimetic apatite on their surfaces

Current driven magnetic permeability interference sensor using NiFe/Cu composite wire with a signal pick-up LC circuit

A novel micro magnetic sensor called the Current Driven Magnetic Permeability Interference (CDMPI) sensor has been developed and the key parameters of the sensor have been studied. The sensor consists of a sensing element in a form of composite wire of a 20 µm copper core electrodeposited with a thin layer of soft magnetic material (Ni 80 Fe 20 ), an ac power source driving the permeability of the magnetic coating layer of the sensing element into a dynamic state, and a signal pickup LC circuit formed by a pickup coil and an capacitor. Experimental studies on the CDMPI sensor have been carried out to investigate the key parameteres in relation to the sensor sensitivity and resolution. The results showed that for high sensitivity and resolution, the frequency and magnitude of the ac driving current through the sensing element each has an optimum value, the resonance frequency of the signal pickup LC circuit should be equal to or twice as the driving frequency on the sensing element, and the anisotropy of the magnetic coating layer of the sensing wire element should be longitudinal

Recruitment Constraints in Singapore's Fluted Giant Clam (Tridacna squamosa) Populations - A Dispersal Model Approach

10.1371/journal.pone.0058819PLoS ONE83

Charge dynamics at heterojunctions for PbS/ZnO colloidal quantum dot solar cells probed with time-resolved surface photovoltage spectroscopy

Time-resolved laser-pump X-ray-photoemission-probe spectroscopy of a ZnO (101 ⎯ ⎯ 0 101¯0 ) substrate with and without PbS quantum dots (QDs) chemically linked to the surface is performed, using laser photon energies resonant with and below the band gap energy of the substrate (λ = 372 and 640 nm, hν = 3.33 and 1.94 eV). Charge injection from the photoexcited QDs to ZnO is demonstrated through the change in the surface photovoltage of the ZnO substrate observed when the heterojunction is illuminated with 1.94 eV radiation. The measured carrier dynamics are limited by the persistent photoconductivity of ZnO, giving dark carrier lifetimes of the order of 200 μs in a depletion layer at the interface. The chemical specificity of soft X-rays is used to separately measure the charge dynamics in the quantum dots and the substrate, yielding evidence that the depletion region at the interface extends into the PbS QD layer

Cell-intrinsic depletion of Aml1-ETO-expressing pre-leukemic hematopoietic stem cells by K-Ras activating mutation

Somatic mutations in acute myeloid leukemia are acquired sequentially and hierarchically. First, pre-leukemic mutations, such as t(8;21) that encodes AML1-ETO, are acquired within the hematopoietic stem cell (HSC) compartment, while signaling pathway mutations, including KRAS activating mutations, are late events acquired during transformation of leukemic progenitor cells and are rarely detectable in HSC. This raises the possibility that signaling pathway mutations are detrimental to clonal expansion of pre-leukemic HSC. To address this hypothesis, we used conditional genetics to introduce Aml1-ETO and K-RasG12D into murine HSC, either individually or in combination. In the absence of activated Ras, Aml1-ETO-expressing HSC conferred a competitive advantage. However, activated K-Ras had a marked detrimental effect on Aml1-ETO-expressing HSC, leading to loss of both phenotypic and functional HSC. Cell cycle analysis revealed a loss of quiescence in HSC co-expressing Aml1-ETO and K-RasG12D, accompanied by an enrichment in E2F and Myc target gene expression and depletion of HSC self-renewal-associated gene expression. These findings provide a mechanistic basis for the observed absence of KRAS signaling mutations in the pre-malignant HSC compartment

Distribution and pathological features of pancreatic, ampullary, biliary and duodenal cancers resected with pancreaticoduodenectomy

BACKGROUND: Pancreatic cancer (PC) has the worst survival of all periampullary cancers. This may relate to histopathological differences between pancreatic cancers and other periampullary cancers. Our aim was to examine the distribution and histopathologic features of pancreatic, ampullary, biliary and duodenal cancers resected with a pancreaticoduodenectomy (PD) and to examine local trends of periampullary cancers resected with a PD. METHODS: A retrospective review of PD between January 2000 and December 2012 at a public metropolitan database was performed. The institutional ethics committee approved this study. RESULTS: There were 142 PDs during the study period, of which 70 cases were pre-2010 and 72 post-2010, corresponding to a recent increase in the number of cases. Of the 142 cases, 116 were for periampullary cancers. There were also proportionately more PD for PC (26/60, 43% pre-2010 vs 39/56, 70% post-2010, P = 0.005). There were 65/116 (56%) pancreatic, 29/116 (25%), ampullary, 17/116 (15%) biliary and 5/116 (4%) duodenal cancers. Nodal involvement occurred more frequently in PC (78%) compared to ampullary (59%), biliary (47%) and duodenal cancers (20%), P = 0.002. Perineural invasion was also more frequent in PC (74%) compared to ampullary (34%), biliary (59%) and duodenal cancers (20%), P = 0.002. Microvascular invasion was seen in 57% pancreatic, 38% ampullary, 41% biliary and 20% duodenal cancers, P = 0.222. Overall, clear margins (R0) were achieved in fewer PC 41/65 (63%) compared to ampullary 27/29 (93%; P = 0.003) and biliary cancers 16/17 (94%; P = 0.014). CONCLUSIONS: This study highlights that almost half of PD was performed for cancers other than PC, mainly ampullary and biliary cancers. The volume of PD has increased in recent years with an increased proportion being for PC. PC had higher rates of nodal and perineural invasion compared to ampullary, biliary and duodenal cancers.Manju D Chandrasegaram, Su C Chiam, John W Chen, Aisha Khalid, Murthy L Mittinty, Eu L Neo, Chuan P Tan, Paul M Dolan, Mark E Brooke-Smith, Harsh Kanhere and Chris S Worthle