On the design of one-level indexed sequential files

We consider in this paper the optimal design of one-level indexed sequential files. The main emphasis is on the case where the request probabilities are not equal for all records. The results are obtained using a continuous approximation of the key values, and they are, thus, asymptotic in the nature.     

Acute dissociation after 1 night of sleep loss.

Recent research has shown that dissociative symptoms are related to self-reports of deviant sleep experiences. The present study is the 1st to explore whether sleep loss can fuel dissociative symptoms. Twenty-five healthy volunteers were deprived of sleep for 1 night. Sleepiness and dissociative symptoms were assessed every 6 hr. The authors measured both spontaneous dissociative symptoms and dissociative symptoms induced by dot-staring during sensory deprivation. Sleepiness as well as spontaneous and induced dissociative symptoms were stable throughout the day but increased during the night. These findings provide further evidence for a robust relationship between disruptions in sleep patterns and dissociative symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermal and chemical inactivation of indigenous Streptococcus thermophilus bacteriophages isolated from Argentinian dairy plants

Thermal and chemical resistance of five autochthonal bacteriophages of Streptococcus thermophilus, isolated from Cuartirolo cheese wheys and yogurt, was investigated. Times to obtain 99% inactivation of phages (T99) at 63 degrees C and 72 degrees C in three suspension media (enriched tryptic soy broth, reconstituted commercial nonfat skim milk, and tris magnesium gelatin buffer) were determined. The thermal resistance was dependent on the phages studied but not detectable counts (<10 PFU/ml) were only achieved by heating at 90 degrees C during 5 min. The data obtained for the three assayed media did not permit verifying significant differences among them. Sodium hypochlorite (100 ppm) provided a fast inactivation of bacteriophage particles (<10 PFU/ml after 5 min). Ethanol, at concentrations of 75% and 100%, was also effective for phage destruction. Isopropanol was slightly less effective than ethanol at the same concentrations. Peracetic acid (0.15%) was also a very effective agent for phage inactivation. The results showed that these autochthonal bacteriophages were not completely inactivated neither by normal pasteurization treatments nor by some biocides commonly used in disinfection, except sodium hypochlorite and peracetic acid. The practical implications of these findings have pointed out the necessity of recognizing the importance of establishing adequate conditions to assure effective thermal and chemical treatments in dairy plants and laboratory environments.     

Data-driven deep density estimation

Neural Computing and Applications - Density estimation plays a crucial role in many data analysis tasks, as it infers a continuous probability density function (PDF) from discrete samples. Thus, it...     

The transpassive dissolution mechanism of highly alloyed stainless steels: I. Experimental results and modelling procedure

The transpassive dissolution of austenitic stainless steels (AISI 316L, AISI 904L, 254SMO and 654SMO) in a 0.5 M sulphate solution with pH 2 was studied by conventional and rotating ring-disc voltammetry, as well as electrochemical impedance spectroscopy. The main process in the transpassive potential region was found to be the release of soluble Cr(VI), while small amounts of lower-valency Cr or Mo species are released as well. Secondary passivation readily occurs for AISI 316L, whereas the remaining highly alloyed steels dissolve at high current densities in the whole potential range studied. The dissolution rate was found to increase in the order AISI 904L<254SMO<654SMO. Thus it can be correlated to the increase in the Cr and especially Mo content of the steel substrate. The impedance spectra contain contributions from the transpassive dissolution of Cr and secondary passivation, probably due to enrichment of Fe in the outermost layer of the surface film. A kinetic model of the process is proposed, including a two-step transpassive dissolution of Cr via a Cr(VI) intermediate and the dissolution of Fe(III) through the anodic film. The model was found to be in quantitative agreement with steady state current vs. potential curves and electrochemical impedance spectra. The kinetic parameters of transpassive dissolution were determined and the relevance of their values is discussed.     

Synthesis and characterization of europium(III) nanoparticles for time-resolved fluoroimmunoassay of prostate-specific antigen

Recent advances in the fabrication and bioconjugation of nanometre-sized lanthanide(III) chelate particles have led to robust high specific activity labels. This paper describes the synthesis and characterization of lanthanide(III) nanoparticle labels and the use of a nanoparticle in a bioaffinity assay system. Two europium(III) nanoparticles were prepared using an extremely simple, inexpensive and fast agglomeration strategy. A?silica-stabilized nanoparticle was synthesized from hydrophobic tris(dibenzoylmethane)-mono(phenanthroline) and tris(dibenzoylmethane)-mono(5-aminophenanthroline) europium(III) chelates in aqueous solution. In addition, a naphthoyl trifluoroacetone:tri-n-octylphosphineoxide:sodium dodecyl sulfate europium(III) complex was agglomerated in water. The particle sizes ranged from 62 to 140?nm in diameter. The silica-stabilized particle was further coated with a monoclonal antibody. The analytical performance of the bioconjugated nanoparticle label was evaluated in a model sandwich immunoassay of prostate-specific antigen. The detection limit of human prostate-specific antigen was 28?ng?l(-1), 850?fM, in a microtiter plate format using time-resolved fluorometry. The coefficient of variation ranged from 1 to 9%. The novel nanoparticle label improves the specific activity of existing lanthanide(III) nanoparticle labels and simplifies the preparation route. In addition, prepared high-density nanoparticle labels using lanthanide(III) chelates or other specific fluorochromes have potential applications in a number of other fields.     

Prediction of the spatial resolution of magnetic particle imaging using the modulation transfer function of the imaging process

The magnetic particle imaging method allows for the quantitative determination of spatial distributions of superparamagnetic nanoparticles in vivo. Recently, it was shown that the 1-D magnetic particle imaging process can be formulated as a convolution. Analyzing the width of the convolution kernel allows for predicting the spatial resolution of the method. However, this measure does not take into account the noise of the measured data. Furthermore, it does not consider a reconstruction step, which can increase the resolution beyond the width of the convolution kernel. In this paper, the spatial resolution of magnetic particle imaging is investigated by analyzing the modulation transfer function of the imaging process. An expression for the spatial resolution is derived, which includes the noise level and which is validated in simulations and experiments.     

Why Turks do not use seat belts? An interview study

Despite the effectiveness of seat belt use and legislation, seat belt use rate is low in Turkey. The aim of this study was to investigate the motives to use and not to use a seat belt in different traveling conditions in a sample of car drivers and passengers. Interviews were made face to face with 221 interviewees from different age and occupation groups. Frequently reported reasons for using a seat belt were traveling conditions, safety, situational conditions, habit of using a seat belt, and avoiding punishment. Frequently reported reasons for not using a seat belt were situational conditions, not believing in the effectiveness, discomfort and having no habit. Safety was the strongest predictor of reported seat belt use in both low and high risk traveling conditions. Findings suggest that seat belt campaigns should mainly emphasize seat belt's safety impact and aim at habit formation.     

Rapid electrochemiluminoimmunoassay of human C-reactive protein at planar disposable oxide-coated silicon electrodes

Electrochemiluminescence (ECL) of aromatic Tb(III) chelates at thin insulating film-coated electrodes provides a means for extremely sensitive detection of Tb(III) chelates and also of biologically interesting compounds if these chelates are used as labels in bioaffinity assays. The suitability of silicon electrodes coated with thermally grown silicon dioxide film as disposable working electrodes in sensitive time-resolved ECL measurements is demonstrated, and a rapid electrochemiluminoimmunoassay (ECLIA) of human C-reactive protein (hCRP) is described. Tb(III) chelate labels can be detected almost down to picomolar level, and the calibration curve of these labels covers more than 6 orders of magnitude of chelate concentration. The calibration curve of the present immunometric hCRP assay was found to be linear over a wide range, approximately 4 orders of magnitude of hCRP concentration, the detection limit of the protein being 0.3 ng mL(-1) (mean background + 2SD) on CV values of about 10-30%, depending on the immunoassay incubation time. In the ECLIA measurements, different incubation times were tested from 15 min (giving above-mentioned performance) to as short as only 2 min, which still gave successful results with approximately 20,000 times better detection limit levels than traditional commercial assay methods. During the ECLIA process, also the Si electrode surface morphology was also investigated by atomic force microscope monitoring.