Steady motion of a crack parallel to a bond plane—further results

The present analysis concerns the steady propagation of a crack of length 2a, parallel to a bond plane between two half-planes having different material properties. The crack speed is less than the transverse wave speed of the half-plane in which it is located, but the material properties of the uncracked material are such that the shear or dilatational wave speeds may be exceeded. A transition speed is seen to exist above which the uncracked medium tends to act as a stiffened material.     

The retention of large particles (greater than 2mum) in fibrous filters

A simple method of testing fibrous filters to obtain the grade efficiency curve in the particle size range 2-22 mum is described. Dust collected by the method has been used to measure the retention efficency of model filters and it is shown that there is a maximun in the grade efficency curve. The influence of relative humidity on filter behaviour has been investigated. It is shown that the efficiency of filtration in high particle inertia systems increases with increasing relative humidity. It is considered that the reason for this is an increase in particle-fiber adhesion force.     

A constrained neural network Kalman filter for price estimation in high frequency financial data

In this paper we present a neural network extended Kalman filter for modeling noisy financial time series. The neural network is employed to estimate the nonlinear dynamics of the extended Kalman filter. Conditions for the neural network weight matrix are provided to guarantee the stability of the filter. The extended Kalman filter presented is designed to filter three types of noise commonly observed in financial data: process noise, measurement noise, and arrival noise. The erratic arrival of data (arrival noise) results in the neural network predictions being iterated into the future. Constraining the neural network to have a fixed point at the origin produces better iterated predictions and more stable results. The performance of constrained and unconstrained neural networks within the extended Kalman filter is demonstrated on "Quote" tick data from the $/DM exchange rate (1993-1995).     

Isolation of sooty mangabey simian T-cell leukemia virus type I [STLV-I(sm)] and characterization of a mangabey T-cell line coinfected with STLV-I(sm) and simian immunodeficiency virus SIVsmmPBj14

It has been postulated that dual infections of humans with human immunodeficiency virus (HIV) and human T-cell leukemia/lymphotropic virus (HTLV) may potentiate disease progression. Counterparts of both of these pathogenic human retroviruses have been identified in various simian species indigenous to Asia and Africa, including sooty mangabey monkeys (Cercocebus atys). Using peripheral blood mononuclear cells (PBMC) from a mangabey naturally infected with both SIV and STLV-I, T-cell lines were established and maintained continuously for more than 3 years; these cell lines harbored only a newly identified mangabey STLV-I(sm) or both STLV-I(sm) and the acutely lethal variant SIVsmmPBj14. The dually infected cell line (FEd-P14) was established by de novo infection of mangabey PBMC with SIVsmmPBj14. This cell line was characterized by multiple assays which showed that structural proteins encoded by both viruses were produced in large quantities, but that the predominant viral glycoprotein on the cell surface was the STLV-I(sm) Env. Unusual interactions of the two retroviral glycoproteins were suggested by the formation of syncytia between Raji and the FEd-P14 cells, but not between Raji and simian cells infected with only one retrovirus or human cells infected with HTLV-I. The STLV-I(sm) strain obtained from the sooty mangabey was transmitted to normal macaque and mangabey PBMC and was shown to be unique by sequencing of the entire env gene. STLV-I(sm) from this African species was more closely related to "cosmopolitan" HTLV-I strains than to the prototypic STLV-I from an Asian pig-tailed macaque. In vitro and in vivo studies of STLV-I(sm) and SIVsmm, both isolated from a naturally infected mangabey monkey, may provide insight into disease induction and manifestations associated with coinfection by their human counterparts.     

Subtypes of stalking (obsessional following) in adolescents

Stalking, which has been given the clinical term "obsessional following", is repetitive threatening or harassing behavior that creates a fear of harm in the victim. Empirical and theoretical literature on this form of behavior is beginning to develop and focuses primarily on adults. Three major subtypes of obsessional following have been identified: erotomania, love obsessional, and simple obsessional/borderline erotomania. Using this typology and available empirical research, a context is set in which three cases of adolescent obsessional following are discussed and analysed. These cases document that stalking/obsessional following occurs in adolescents and that important similarities and differences appear to exist between adult and adolescent offenders. Hypotheses are generated to encourage further study of this significant problem.