Critical analysis of the eigenfilter method for the design of FIR filters and wideband beamformers

The least squares based eigenfilter method has been applied to the design of both finite impulse response (FIR) filters and wideband beamformers successfully. It involves calculating the resultant filter coefficients as the eigenvector of an appropriate Hermitian matrix, and offers lower complexity and less computation time with better numerical stability as compared to the standard least squares method. In this paper, we revisit the method and critically analyze the eigenfilter approach by revealing a serious performance issue in the passband of the designed FIR filter and the mainlobe of the wideband beamformer, which occurs due to a formulation problem. A solution is then proposed to mitigate this issue, and design examples for both FIR filters and wideband beamformers are provided to demonstrate the effectiveness of the proposed method

Thermal history of the early Miocene Waitemata Basin and adjacent Waipapa Group, North Island, New Zealand

Apatite fission track (AFT) and vitrinite reflectance (VR) data for early Miocene outcrops from the Waitemata Basin reveal that the basin sequence was subjected to shallow burial before denudation. AFT results suggest that the total sediment thickness within the basin was <=1 km and maximum paleotemperatures during burial never exceeded c. 60deg.C. Statistical analyses of the detrital AFT ages distinguish four dominant sources of sediment supply: contemporaneous volcanism; metagreywacke rocks of the Waipapa Group; the Northland Allochthon; and an unidentified source south of the basin. The apatite and zircon fission track results from the Waipapa Group rocks (Gondwana Terrane) adjacent to the basin suggest two discrete phases of accelerated cooling: the first during the early Cretaceous (c. 117 Ma) and the second during the mid Cretaceous (c. 84 Ma). These events probably reflect key stages in the tectonic development of the New Zealand microcontinent during the Cretaceous period, the earlier event being related to the climax of compressional deformation (Rangitata Orogeny) and the latter to extensional tectonism associated with the opening of the Tasman Sea. Waipapa Group rocks now exposed at the surface cooled from maximum paleotemperatures of c. 250deg.C at an estimated rate of c. 180-36deg.C/m.y., involving substantial denudation

Displaced thinned coprime arrays with an additional sensor for DOA estimation

A new sparse array structure based on the recently proposed thinned coprime arrays is proposed to maximize the number of unique lags. The design process involves two stages: the first stage displaces one subarray from its original position for an increase in the number of lags; as the displacement results in the minimum interelement spacing equal to integer multiples of half-wavelength, an additional sensor at a distance of half-wavelength is then added in the displaced subarray to avoid spatial aliasing. The strategic location of the additional sensor results in a significant increase in the overall unique lags which can be utilized for direction-of-arrival estimation (DOA) using compressive sensing based methods. Furthermore, the new structure has excellent performance in the presence of mutual coupling as shown by simulation results

Nanoplasmonics beyond Ohm's law

In tiny metallic nanostructures, quantum confinement and nonlocal response change the collective plasmonic behavior with important consequences for e.g. field-enhancement and extinction cross sections. We report on our most recent developments of a real-space formulation of an equation-of-motion that goes beyond the common local-response approximation and use of Ohm's law as the central constitutive equation. The electron gas is treated within a semi-classical hydrodynamic model with the emergence of a new intrinsic length scale. We briefly review the new governing wave equations and give examples of applying the nonlocal framework to calculation of extinction cross sections and field enhancement in isolated particles, dimers, and corrugated surfaces.Comment: Invited paper for TaCoNa-Photonics 2012 (www.tacona-photonics.org), to appear in AIP Conf. Pro

Strain and field modulation in bilayer graphene band structure

Using an external electric field, one can modulate the bandgap of Bernal stacked bilayer graphene by breaking A-~B symmetry. We analyze strain effects on the bilayer graphene using the extended Huckel theory and find that reduced interlayer distance results in higher bandgap modulation, as expected. Furthermore, above about 2.5 angstrom interlayer distance, the bandgap is direct, follows a convex relation to electric field and saturates to a value determined by the interlayer distance. However, below about 2.5 angstrom, the bandgap is indirect, the trend becomes concave and a threshold electric field is observed, which also depends on the stacking distance.Comment: 3 pages, 5 figures - v1 and v2 are the same, uploaded twice - v3, some typos fixed and a reference adde

A Novel Use for the Rigid Cystoscope: The Removal of Sacral Tacks after a Coloanal Anastamosis Dehiscence

A 69-year-old female presented as an emergency with atrial fibrillation, which was treated with warfarin. She subsequently developed fresh rectal bleeding and after further investigations a Dukes B adenocarcinoma of the rectum was found. She subsequently underwent a low anterior resection, coloanal anastamosis and a defunctioning ileostomy. Three sterile surgical metallic tacks (pins) were inserted into the sacrum to stop brisk bleeding from the presacral venous plexus. Following discharge, she was readmitted with septic shock and a CT scan revealed a presacral fluid collection in the area surrounding the sacral tacks (pins) and an anastamotic dehiscence. The patient was not fit for further pelvic surgery to remove the tacks, so an alternative minimally invasive cystoscopic procedure was performed. The sacral tacks (pins) were removed by the urologist using a rigid cystoscope and cold cup biopsy forceps. To our knowledge, this is the first reported case in the literature

Synthesis of visible light driven TiO2 coated carbon nanospheres for degradation of dyes

Herein, we report the successful synthesis of visible light driven metal doped TiO2 coated carbon nanospheres (CNS) via a facile hydrothermal approach. The synthesized materials were characterized by standard analytical techniques, such as XRD, SEM-EDS-mapping, TEM, FTIR, PL, Raman and UV-Vis absorption spectroscopy. The effect of dopants on the band gap energy, crystallite size and photocatalytic properties of the TiO2 coated CNS was investigated systematically. The incorporation of dopants in TiO2 matrix found to significantly extend the absorption edge toward visible region and efficient separation of charge carriers on excitation. The photodegradation of two different organic dyes were investigated to evaluate the activity of the photocatalyst under different conditions such as dopant percentage, catalyst dose, different quenchers and calcination temperature. The best photocatalytic activity was observed with 3.0% Ce, doped TiO2 coated CNS with 1.5gL-1 concentration calcined at 400°C. We also performed the antibacterial activity of pure and doped-TiO2 coated CNS against pathogenic gram negative and gram positive bacteria. The doped-TiO2 coated CNS exhibited excellent antibacterial activity against both bacteria

Incoherent Transport through Molecules on Silicon in the vicinity of a Dangling Bond

We theoretically study the effect of a localized unpaired dangling bond (DB) on occupied molecular orbital conduction through a styrene molecule bonded to a n++ H:Si(001)-(2x1) surface. For molecules relatively far from the DB, we find good agreement with the reported experiment using a model that accounts for the electrostatic contribution of the DB, provided we include some dephasing due to low lying phonon modes. However, for molecules within 10 angstrom to the DB, we have to include electronic contribution as well along with higher dephasing to explain the transport features.Comment: 9 pages, 5 figure

Health services utilization and out-of-pocket (OOP) expenditures in public and private facilities in Pakistan: An empirical analysis of the 2013-14 OOP health expenditure survey

Background: As low- and middle-income countries progress toward Universal Health Coverage, there is an increasing focus on measuring out-of-pocket (OOP) expenditure and health services utilization within countries. While there have been several reforms to improve health services coverage and financial protection in Pakistan, there is limited empirical research comparing OOP expenditure and health services utilization between public and private facilities and exploring their determinants, a knowledge gap addressed in this study.Methods: We used data from 2013 to 14 OOP Health Expenditure Survey, a population-based household survey carried out for Pakistan\u27s National Health Accounts. The analysis included 7969 encounters from 4293 households. We conducted bivariate analyses to describe patterns of care utilization, estimated annualized expenditures by type and sector of care, and assessed expenditure composition. We used multivariable logistic regression modeling to identify factors associated with sector of care and generalized linear model (GLM) with log link and gamma distribution to identify determinants of OOP expenditures stratified by type of care (inpatient and outpatient).Results: Most encounters (82.5%) were in the private sector and were for outpatient visits (85%). Several public-private differences were observed in annualized expenditures and expenditure components. Logistic regression results indicate males, wealthier individuals, Punjab and Sindh residents, and those in smaller households were more likely to access private outpatient care. In the inpatient model, rural residents were more likely to use a private provider, while Khyber Pakhtunkhwa residents were less likely to use private care. GLM results indicate private sector inpatient expenditures were approximately PKR 6660 (USD 61.8) higher than public sector expenditures, but no public-private differences were observed for outpatient expenditures. Several demographic factors were significantly associated with outpatient and inpatient expenditures. Of note, expenditures increased with increasing wealth, decreased with increasing household size, and differed by province and region.Conclusions: This is the first study comprehensively investigating how healthcare utilization and OOP expenditures vary by sector, type of care, and socio-economic characteristics in Pakistan. The findings are expected to be particularly useful for the next phase of social health protection programs and supply side reforms, as they highlight sub-populations with higher OOP and private sector utilization