Sequential testing of sorted and transformed data as an efficient way to implement long GLRTs

It is often required to detect a long weak signal in Gaussian noise, and frequently, the exact form of that signal is parameterized but not known. A bank of matched filters provides an appropriate detector. However, in some practical applications, there are very many matched filters, and most are quite long. The consequent computational needs may render the classical bank-of-filters approach infeasibly expensive. One example, and our original motivation, is the detection of chirp gravitational waves by an Earth-based interferometer. In this paper, we provide a computational approach to this problem via sequential testing. Since the sequential tests to be used are not for constant signals, we develop the theory in terms of average sample number (ASN) for this case. Specifically, we propose two easily calculable expressions for the ASN: one a bound and the other an approximation. The sequential approach does yield moderate computational savings, but we find that by preprocessing the data using short/medium fast Fourier transforms (FFTs) and an appropriate sorting of these FFT outputs such that the most informative samples are entered to a sequential test first, quite high numerical efficiency can be realized. The idea is simple but appears to be quite successful: Examples are presented in which the computational load is reduced by several orders of magnitude. The FFT is an example of an energy-agglomerating transform, but of course, there are many others. The point here is that the transform need not match the sought signal exactly in the sense that all energy becomes confined to a single sample; it is enough that the energy becomes concentrated, and the more concentrated the better.     

Characterization of the specificities of human blood group H gene-specified alpha 1,2-L-fucosyltransferase toward sulfated/sialylated/fucosylated acceptors: evidence for an inverse relationship between alpha 1,2-L-fucosylation of Gal and alpha 1,6-L-fucosylation of asparagine-linked GlcNAc

The assembly of complex structures bearing the H determinant was examined by characterizing the specificities of a cloned blood group H gene-specified alpha 1,2-L-fucosyltransferase (FT) toward a variety of sulfated, sialylated, or fucosylated Gal beta 1,3/4GlcNAc beta- or Gal beta 1,3GalNAc alpha-based acceptor structures. (a) As compared to the basic type 2, Gal beta 1,4GlcNAc beta-(K(m) = 1.67 mM), the basic type 1 was 137% active (K(m) = 0.83 mM). (b) On C-6 sulfation of Gal, type 1 became 142.1% active and type 2 became 223.0% active (K(m) = 0.45 mM). (c) On C-6 sulfation of GlcNAc, type 2 showed 33.7% activity. (d) On C-3 or C-4 fucosylation of GlcNAc, both types 1 and 2 lost activity. (e) Type 1 showed 70.8% and 5.8% activity, respectively, on C-6 and C-4 O-methylation of GlcNAc. (f) Type 1 retained 18.8% activity on alpha 2,6-sialylation of GlcNAc. (g) Terminal type 1 or 2 of extended chain had lower activity. (h) With Gal in place of GlcNAc in type 1, the activity became 43.2%. (i) Compounds with terminal alpha 1,3-linked Gal were inactive. (j) Gal beta 1,3GalNAc alpha- (the T-hapten) was approximately 0.4-fold as active as Gal beta 1,4GlcNAc beta-. (k) C-6 sulfation of Gal on the T-hapten did not affect the acceptor activity. (l) C-6 sulfation of GalNAc decreased the activity to 70%, whereas on C-6 sulfation of both Gal and GalNAc the T-hapten lost the acceptor ability. (m) C-6 sialylation of GalNAc also led to inactivity. (n) beta 1,6 branching from GalNAc of the T-hapten by a GlcNAc residue or by units such as Gal beta 1, 4GlcNAc-, Gal beta 1,4(Fuc alpha 1,3)GlcNAc-, or 3-sulfoGal beta 1,4GlcNAc- resulted in 111.9%, 282.8%, 48.3%, and 75.3% activities, respectively. (o) The enhancement of enzyme affinity by a sulfo group on C-6 of Gal was demonstrated by an increase (approximately 5-fold) in the K(m) for Gal beta 1,4GlcNAc beta 1,6(Gal beta 1,3)GalNAc alpha-O-Bn in presence of 6-sulfoGal beta 1,- 4GlcNAc beta-O-Me (3.0 mM). (p) Among the two sites in Gal beta 1, 4GlcNAc beta 1,6(Gal beta 1,3) GalNAc alpha-O-Bn, the enzyme had a higher affinity ( > 3-fold) for the Gal linked to GlcNAc. (q) With respect to Gal beta 1,- 3GlcNAc beta-O-Bn (3.0 mM), fetuin triantennary asialo glycopeptide (2.4 mM), bovine IgG diantennary glycopeptide (2.8 mM), asialo Cowper's gland mucin (0.06 mM), and the acrylamide copolymers (0.125 mM each) containing Gal beta 1,3GlcNAc beta-, Gal beta 1,3(6-sulfo)GlcNAc beta-, Gal beta 1,3GalNAc alpha-, Gal beta 1,3Gal beta-, or Gal alpha 1,3Gal beta- units were 153.6%, 43.0%, 6.2%, 52.5%, 94.9%, 14.7%, 23.6%, and 15.6% active, respectively. (r) Fucosylation by alpha 1,2-L-FT of the galactosyl residue which occurs on the antennary structure of the bovine IgG glycopeptide was adversely affected by the presence of an alpha 1,6-L-fucosyl residue located on the distant glucosaminyl residue that is directly attached to the asparagine of the protein backbone. This became evident from the 4-fold activity of alpha 1,2-L-FT toward bovine IgG glycopeptide after approximately 5% removal of alpha 1,6-linked Fuo.     

Evaluation of sport injuries in children and adolescents

Dengue type 2 virus (DV)-induced cytotoxic factor (CF) is capable of reproducing various pathological lesions in mice that are seen in human dengue. The present study was undertaken to investigate the protective effect of active immunization of mice with CF. Mice were immunized with 5 microgram of CF and prevention of CF-induced increase in capillary permeability and damage to the blood-brain barrier were studied at weekly intervals, up to 48 weeks, by challenging with 3 microgram of CF. Maximum protection against increase in capillary permeability and damage to the blood-brain barrier was observed in week 4 after immunization. A breakthrough in the protection occurred with higher doses of CF in a dose-dependent manner. Challenge with a lethal intracerebral (i.c.) dose of DV showed significantly prolonged mean survival time and delayed onset of symptoms of sickness in the immunized mice compared with the normal mice, but the titre of the virus in the brain was similar in the two groups. On i.p. challenge with the virus the protection against damage to the blood-brain barrier was 86 +/- 7% at week 4 and 17 +/- 4% at week 26 after immunization. Sera obtained from the immunized mice showed the presence of CF-specific antibodies by ELISA, Western blot, and by neutralization of the cytotoxic activity of CF in vitro. The present study describes successful prevention of a cytokine-induced pathology by specific active immunization.     

Catalytic Combustion of Model Carbon Particles (CPs) over Pt/β-SiC Catalyst

Platinum catalyst supported on a medium surface area -SiC was successfully used for the catalytic combustion of model carbon particles and compared to a catalyst supported on a low surface area -SiC. The -SiC-based catalyst showed no deactivation as a function of cycling tests while a strong deactivation was observed on the -SiC-based catalyst. This deactivation was attributed to the progressive encapsulation of the platinum particles by a layer of silica which built up during the combustion cycle. These results render possible the use of Pt/-SiC catalyst as a diesel carbon particle catalytic filter with continuous regeneration.     

Full Film, Boundary Lubrication and Tribochemistry in Steel Circular Contacts Lubricated with Glycerol

In this article, the lubricating properties of pure glycerol are investigated under both mild and severe EHL regimes. Amazingly low friction coefficients (about 0.01) are reported by experiments in thick film regimes compared to traditional base oils. EHL calculations of film thickness and friction (including thermal effects) predict friction coefficients that are twice those actually found for glycerol. Chemical analysis of glycerol before and after the friction tests were performed by NMR and Karl Fischer methods, and they reveal that water is produced by tribochemical reaction as well as other species like aldehydes. This finding is in agreement with a corrosion pattern observed inside the wear scars of the steel samples. This study provides an explanation to the anomalously low friction observed in the thick film regime. In fact, water produced in the lubricant decreases traction forces due to the drastic decrease of the viscosity of glycerol with water addition.     

226Ra, 228Ra and 228Th in scale and sludge samples from the Campos Basin oilfield E&P activities

More than 40 scale and sludge samples from the Campos Basin oilfield were analysed in terms of 226Ra, 228Ra and 228Th. Although the exact origin of the samples was not known, scale samples derived from production pipes and sludge samples from water-oil separation units. Reported values ranged from 0.13 to 331 kBq.kg(-1) for 226Ra, from 0.10 to 245 kBq.kg(-1) for 228Ra and <0.10 to 272 kBq.kg(-1) for 228Th in sludge samples. The concentrations in scales were much more regular than in sludges and ranged from 16.2 to 93.2 kBq.kg(-1) for 226Ra, from 4.0 to 36.9 kBq.kg(-1) for 228Ra and from 4.5 to 18.5 kBq.kg(-1) for 228Th. Based on the Basic Safety Standards recommendations and on the derived results, these activities cannot be regarded as exempted and specific procedures should be designed for their radiological control.     

Acoustic Emission Damage Assessment of Steel/CFRP Bonds for Rehabilitation

The use of adhesively bonded carbon fiber reinforced polymer (CFRP) laminates is increasingly being considered for the rehabilitation of metallic structures. The effective structural monitoring of steel/CFRP adhesive joints is of critical importance to assess the design service performance of the system, which ultimately depends on the bond damage tolerance at the load transfer regions. In the present study laboratory static and fatigue tests were conducted on steel/CFRP skin doubler and double strap joint specimens, which were monitored using the acoustic emission (AE) technique. The characteristics of the AE signals were correlated with the mechanical response of the samples, in order to understand the AE response associated with the accumulation of bond damage. One-dimensional source location was also performed to examine the initiation and the development of the disbond. The results show that AE parameter-based analysis is an effective nondestructive evaluation tool for bond damage detection and area location.     

The role of thermal diffusivity in the machining performance of oxide ceramic cutting tool materials

The machining performance of oxide ceramic cutting tools was correlated with their values of thermal diffusivity, hardness and density. It was found that high crater wear resistance requires high values of the thermal diffusivity, hardness and density. High flank wear resistance requires a high value of thermal diffusivity, but is independent of hardness. In contrast, a good surface finish of the steel workpiece (AISI 4340) requires a combination of low thermal diffusivity and low hardness.