A warped kernel improving robustness in Bayesian optimization via random embeddings

This works extends the Random Embedding Bayesian Optimization approach by integrating a warping of the high dimensional subspace within the covariance kernel. The proposed warping, that relies on elementary geometric considerations, allows mitigating the drawbacks of the high extrinsic dimensionality while avoiding the algorithm to evaluate points giving redundant information. It also alleviates constraints on bound selection for the embedded domain, thus improving the robustness, as illustrated with a test case with 25 variables and intrinsic dimension 6

Polyribosomes associated with synaptic specializations on axon initial segments: localization of protein-synthetic machinery at inhibitory synapses.

Previous studies have revealed a selective association between polyribosomes and axospinous synapses in a variety of brain regions. The present study evaluates whether polyribosomes are also associated with the symmetrical and presumably inhibitory synaptic connections found on the initial segment of axons of some neurons in the CNS. The initial segments of pyramidal neurons in the sensorimotor cortex of the monkey and of granule cells in the hippocampus of the rat were examined. The initial segments of these cell types are contacted by GABAergic terminals that form symmetrical synaptic connections. In the present study, these initial segments were found to contain polyribosomes that tended to be selectively localized beneath the synaptic specializations. Both the synaptic connections and the polyribosomes were localized to the initial segment; after the point at which the axon became myelinated, neither synapses nor polyribosomes were found. The association between polyribosomes and synapses was also suggested by the position of the polyribosomes with respect to the synapse. In each cell type, the majority of the polyribosomes that were present in the initial segments appeared to be localized preferentially beneath synaptic sites, although some polyribosomes were also present in the core of the axon. These data reveal that polyribosomes are not peculiar to spine synapses, but rather are ubiquitous components of the subsynaptic region of many types of synapses. We propose that neurons may regulate their innervation by positioning protein-synthetic machinery (and appropriate mRNA molecules) at particular locations in order to construct particular types of synapses at defined positions on the postsynaptic cells' receptive surface

Oxidative stress and superoxide dismutase activity in brain of rats fed with diet containing permethrin

Many pesticides have been reported to cause a lot of health problems in workers, users and non-target organisms in the environment. Permethrin containing insect pesticide has been reported to be toxic to non-target organisms. However, the underlying mechanism involved inthe toxicity is not well understood. The present study was envisaged to investigate the possible role of oxidative stress in permethrin neurotoxicity and to evaluate the protective effect of superoxide dismutase (SOD) activity in brain homogenates of Wistar rats. Oxidative stress measured as thiobarbituric acid reacting substances (TBARS) was found to significantly increase (p < 0.05) in all the experimental groups compared with their parallel controls. Concomitantly, the activity of SOD was found to decrease or increase significantly (p < 0.05) in the experimental groups compared with their controls. Our result also showed that activity of SOD was aged and concentration dependent. Hence, the newly weaned ratsappear to be more susceptible to the pesticide contaminated diet because the SOD activity decreased more in the brain homogenates compared with the middle aged rats or aged rats. Observed aggressive behaviour was noticed in the pesticide exposed rats, hence a possibleneurobehavioral effect. The result demonstrated that the pyrethroid insect powder exerts its toxic effect by promoting oxidative stress in the brain and this may affect normal brain functioning and growth

Event characteristics and socio-demographic features of rape victims presenting for post exposure prophylasix at the Federal Medical Centre, Owerri Nigeria

Objectives: On account of increasing awareness of the need for Post exposure prophylaxis (PEP) and availability of requisite drugs, victims of rape are now presenting at health facilities including ours to access PEP for HIV. This study set to document the socio-demographic features of these victims and the event characteristic of the rape act.Methods: The medical records of patients who presented between January 2009 and December 2013 to the Paediatric infectious diseases clinic of Federal medical Owerri for PEP were reviewed.Results: One hundred and fifty three patients presented over reviewed period. 148(96.7%) presented for PEP on account of rape. They consisted of 147 females and 1male.61 (41.2%) of victims previously knew and could identify their assailants while 19(12.8%) of the victims had been previously raped. 32 (21.6%) victims presented on the day of the rape and weapons were used in 27% of the cases to ensure the victims cooperation. The most common place for the rape act was the assailant's home.None of the victims completed the schedule of follow up visits.Conclusion: Rape remains the commonest reason for presentation at our centre for PEP. Most victims still present late and are nearly always lost to follow-up after the initiation of PEP.Keywords: HIV, Rape, Post exposure prophylaxis, Criminal code

The prevalence of human immunodeficiency virus infection among TB patients in Port Harcourt Nigeria

The joint statement by the American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America recommends that all patients with tuberculosis (TB) undergo testing for human immunodeficiency virus (HIV) infection after counseling. In this study, we investigated the prevalence of HIV infection among 120 patients diagnosed with microbiologically proven TB aged 18 to 54 years with a mean age of 39.5 years (standard deviation 6.75). The subjects studied were 36 male (30%) and 84 females (70%). Enzyme-linked immunosorbent assay methods were used to screen for HIV infection among the subjects. Of the 120 TB patients tested 30 (25%) were positive for HIV infection. The prevalence of HIV was higher in females 24 (80%) compared to males 6 (20%) and among singles (66.7%) compared to married subjects (33.3%) (χ2 = 83.5 and χ2 = 126.2, respectively P = 0.001). HIV-1 was the predominant viral subtype. HIV prevalence was significantly higher in subjects in the 38–47 year and 28–37 year age groups (both 40%) followed by the 18–28 year age group (20%) (χ2 = 42.6, P = 0.05). The mean CD4 lymphocyte count of the HIV-infected TB subjects was significantly lower (195 ± 40.5 cells/μL) compared to the non-HIV infected (288 ± 35.25 cells/μL P = 0.01). This study has shown a high prevalence of HIV among TB patients. Reactivation of TB among people living with HIV can be reduced by TB preventive therapy and by universal access to antiretroviral therapy

Dynamical R-Matrices for Integrable Maps

The integrability of two symplectic maps, that can be considered as discrete-time analogs of the Garnier and Neumann systems is established in the framework of the $r$-matrix approach, starting from their Lax representation. In contrast with the continuous case, the $r$-matrix for such discrete systems turns out to be of dynamical type; remarkably, the induced Poisson structure appears as a linear combination of compatible ``more elementary" Poisson structures. It is also shown that the Lax matrix naturally leads to define separation variables, whose discrete and continuous dynamics is investigated.Comment: 16 plain tex page