A Language for Verification and Manipulation of Web Documents: (Extended Abstract)

In this paper we develop the language theory underpinning the logical framework PLF. This language features lambda abstraction with patterns and application via pattern-matching. Reductions are allowed in patterns. The framework is particularly suited as a metalanguage for encoding rewriting logics and logical systems where proof terms have a special syntactic constraints, as in term rewriting systems, and rule-based languages. PLF is a conservative extension of the well-known Edinburgh Logical Framework LF. Because of sophisticated pattern matching facilities PLF is suitable for verification and manipulation of HXML documents.     

On the Existence of Epipolar Matrices

This paper considers the foundational question of the existence of a fundamental (resp. essential) matrix given m point correspondences in two views. We present a complete answer for the existence of fundamental matrices for any value of m. We disprove the widely held beliefs that fundamental matrices always exist whenever \(m \le 7\). At the same time, we prove that they exist unconditionally when \(m \le 5\). Under a mild genericity condition, we show that an essential matrix always exists when \(m \le 4\). We also characterize the six and seven point configurations in two views for which all matrices satisfying the epipolar constraint have rank at most one.     

Retinopathy of prematurity: incidence and risk factors

OBJECTIVE: To determine the incidence of Retinopathy of Prematurity (ROP) in high risk babies admitted to the neonatal unit and to study risk factors for it's development. DESIGN: Prospective cohort study. SETTING: Level II Neonatal Intensive Care Unit. SUBJECTS: 100 babies admitted to the neonatal unit during a 4 year period who were below 1500 g or whose gestation was < or = 34 weeks. METHODS: Examination of the eye was done in the neonatal unit or in the neonatal follow up clinic by an Ophthalmologist by indirect Ophthalmoscopy at 4-6 weeks postnatal age. RESULTS: The incidence of ROP was 46%. Of the 100 babies screened, 21 had stage I, 14 had stage II, 8 had stage III and 3 had stages IV and V. The incidence of ROP was 73.3% among < 1000 g babies and 47.3% among < 1500 g babies. The incidence of ROP among 28-29 weeks, 30-31 weeks and 32-33 weeks babies was 83%, 60% and 50%, respectively. The maximum stage of ROP developed between 37-42 weeks post conceptional age in 69% subjects. On univariate analysis, gestation < or = 32 weeks, anemia, Blood transfusions, apnea and exposure to oxygen significantly increased the risk of developing ROP. On multivariate logistic regression analysis, anemia and duration of oxygen therapy were the significant independent predictors of development of ROP. Nine of the 46 babies underwent cryotherapy for threshold ROP. CONCLUSION: The incidence of ROP among high risk babies is significant and duration of oxygen therapy and anemia are independent factors predicting the development of ROP. All high risk babies should be screened for ROP. Cryotherapy is a relatively simple procedure which can be done in the neonatal unit.     

Gellan gum for reducing oil uptake in sev,a legume based product during deep-fat frying

Gellan gum, a high molecular weight anionic linear polysaccharide produced by pure culture fermentation from Sphingomonas paucimobilis ATCC 31461 is used in a variety of food applications that are based on its unique gelling profile. The present work reports on the effective use of gellan gum on the oil uptake of a traditional Indian deep-fat fried product, sev that is based on chickpea flour. The effect of addition of gellan gum at 0.25–0.75% (w/w) (based on chickpea flour) on the dough texture, and that of the sev prepared was also evaluated using TA.XT2i Texture Analyzer. Addition of gellan gum at 0.25% (w/w) markedly reduced the oil content in the sev from 37.02% in the control to 27.91%. The reduction in oil content beyond 0.25% gellan gum addition was not significant (P = 0.05). Furthermore, while addition of gellan gum significantly altered the texture of dough, it did not significantly affect the texture of sev (P = 0.05). Addition of 0.25% gellan gum in combination with sodium alginate (0.25–1.00%), carboxymethylcellulose (0.25–1.00%) or soy protein isolate (2.5–10.0%) did not affect oil uptake significantly (P = 0.05) as compared to that prepared by the addition of 0.25% gellan gum alone.     

Usability study of digital libraries: ACM, IEEE-CS, NCSTRL, NDLTD

If digital libraries are to be used effectively, their user interfaces should be tested and enhanced. We observed 48 participants as they worked with the following digital libraries: ACM, IEEE-CS, NCSTRL, and NDLTD. We discuss how the features of these digital libraries influence the subjects’ efforts to perform search and retrieval tasks. Data analysis indicates that the IEEE-CS digital library was rated the best overall and NDLTD had the best search time. We present user recommendations and propose a taxonomy of features that we believe are essential for the design of future digital libraries. Noteworthy is the observation that users’ judgements on the importance of different features varied widely between the beginning and end of their test sessions. Received: 15 December 1997 / Revised: June 1999     

Modeling coupled migration and settling of particulates in curing filled epoxies

Epoxy resins filled to a high solids loading (40–60% by volume) with noncolloidal particles are used to mitigate stress and vibration in electronic components. We perform continuum‐level finite element method (Schunk et al., A Full‐Newton Finite Element Program for Free and Moving Boundary Problems with Coupled Fluid/Solid Momentum, Energy, Mass, and Chemical Species Transport: User's Guide, Sandia National Laboratories) simulations of filler particle redistribution during the nonisothermal cure of the epoxy under both quiescent and bulk flow conditions. An extent of reaction is used to track the degree of cure. To determine the particle migration, we couple a diffusive flux suspension model (Zhang and Acrivos, Int J Multiphase Flow 1994, 20, 579.) with the curing model. The heat transfer, including the exothermic polymerization reaction, is also modeled. The result is a generalized Newtonian model that has viscosity as a function of temperature, cure and particle volume fraction. With x‐ray computed tomography, we examine settling of the particulate phase in both flowing and quiescent curing systems and compare the experimental results to the model predictions. The model is also validated with temperature measurements. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Detection and characterization of Salmonella associated with tropical seafood

The prevalence of Salmonella in seafood samples collected from the southwest coast of India was studied by conventional culture and by a DNA based molecular technique, polymerase chain reaction (PCR). While conventional culture techniques detected Salmonella in only 20 out of the 100 samples analyzed, direct enrichment lysate PCR detected 52 as positive for Salmonella. A set of three different PCR primers viz., hns, invA and invE were used. It was observed that hns primer detected Salmonella in a significantly higher number of samples. Fourteen out of nineteen isolates belonged to serovar S. enterica Weltevreden. S. Weltevreden isolates were genotyped yielding 4 different patterns both by RAPD and ERIC-PCR but when combined, the overall results discriminated the isolates of S. Weltevreden into 6 different types. This suggests that genetically diverse Salmonella Weltevreden are prevalent in seafood.     

Purification of Lycopene by Reverse Phase Chromatography

This work investigates the potential of various hydrophobic matrices for the separation and purification of lycopene from microbial biomass obtained from fermentation using Blakeslea trispora. The lycopene purification method was developed in two steps. In the first step, carotenoids were extracted from the biomass of B. trispora with petroleum ether/acetone (1:1). In the second step, this partially purified carotenoid extract was further purified by reverse phase chromatography technique. Various binding conditions were studied to achieve maximum amount of lycopene bound onto the chromatographic matrices. Column studies on the elution conditions of lycopene using linear and step gradient method were investigated. Purification of lycopene using packed bed column by reverse phase chromatography matrix HP20 was carried out using step gradient of 55% isopropyl alcohol in acetone followed by 65% isopropyl alcohol in acetone. The purity and recovery of lycopene was checked using Knauer high-performance liquid chromatography (HPLC) system. A 89% recovery of lycopene of HPLC purity 95% was achieved with substantial success. Proton magnetic resonance of the purified sample showed close resemblance with the chemical shifts (δ values) of the standard lycopene.     

Incidence and Molecular Typing of Vibrio parahaemolyticus from Tiger Shrimp Culture Environments along the Southwest Coast of India

Vibrio parahaemolyticus is one of the most prevalent food-borne pathogens along the southwest coast of India, where marine foods are frequently consumed. Shrimp (Penaeus monodon) and environmental samples were collected from aquaculture farms located in and around Cochin. Confirmation of the biochemically identified strains with species-specific toxR gene and detection of virulent genes viz., tdh and trh was performed by polymerase chain reaction (PCR). The phenotypic markers for the presence of tdh and trh genes were assayed by Kanagawa phenomenon and urease activity, respectively. Protease activity was examined to identify other potential virulence factors. After phenotypic characterization of bacterial strains fingerprinting of genomic DNA was carried by various typing methods, viz., random amplified polymorphic DNA (RAPD), enterobacterial repetitive intergenic consensus sequence (ERIC), repetitive extragenic palindromic sequence (REP), and ribosomal gene spacer sequence (RS) PCR methods to assess the genetic diversity within the isolates. Eighteen percent of the samples were found positive for the incidence of V. parahaemolyticus by biochemical protocols and toxR (368 bp) targeted PCR. PCR analyses revealed 1% of the samples positive for tdh (269 bp) and trh (500 bp) gene. RAPD analysis revealed clustering of toxigenic strains into a single group. Cluster analysis revealed the conglomeration of isolates into two, five, and seven major groups using RS, ERIC, and REP PCR methods, respectively. RS PCR generated fewer amplified bands compared to REP and ERIC PCR methods, thus giving scope for higher discrimination. Moreover, RS PCR patterns were more discernible visually from other patterns, suggesting RS PCR as a considerably practical method for routine use.