98 research outputs found

    Dynamic evolving neural-fuzzy inference system for rainfall-runoff (R-R) modelling

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    Dynamic Evolving Neural-Fuzzy Inference System (DENFIS) is a Takagi-Sugeno-type fuzzy inference system for online learning which can be applied for dynamic time series prediction. To the best of our knowledge, this is the first time that DENFIS has been used for rainfall-runoff (R-R) modeling. DENFIS model results were compared to the results obtained from the physically-based Storm Water Management Model (SWMM) and an Adaptive Network-based Fuzzy Inference System (ANFIS) which employs offline learning. Data from a small (5.6 km2) catchment in Singapore, comprising 11 separated storm events were analyzed. Rainfall was the only input used for the DENFIS and ANFIS models and the output was discharge at the present time. It is concluded that DENFIS results are better or at least comparable to SWMM, but similar to ANFIS. These results indicate a strong potential for DENFIS to be used in R-R modeling

    Survival Models in Breast Cancer Patients

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    Abstract Background: Breast cancer is the most prevalent malignancy among Iranian women. Five and ten year survival is one of the indicators used for evaluation of the quality of care after surgery. In this study, we used several survival models to determine risk factors, survival times and life expectancies of different types of surgery

    Study of genotype, subtype and mutation in the S gene in hepatitis B patients co-infected with HIV in Iran

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    Background: Co-infection with human immunodeficiency virus (HIV) and hepatitis B virus (HBV) is common due to shared routes of transmission, as reported approximately 10% of 33 million HIV-infected patients worldwide are chronically infected with HBV. Mutations of HBsAg especially within the “a” determinant could alter the antigenicity of the protein, causing failure of HBsAg neutralization and escaping from the host’s immune system. This results in active viral replication and liver disease. Objectives: The aim of the survey was to identify HBV genotype and subtype, and different mutations in HBV S gene in hepatitis B patients co-infected with HIV in Iran. Methods: PCR performance and HBV-DNA extraction from plasma of 124 samples obtained from treatment naive HIV/HBV coinfected participants were according to the protocol. Direct sequencing and alignment of surface gene were carried out using reference sequences from the Gene Bank database. Results: From 124 HIV/HBV ELISA positive samples, 40 were HBV DNA-positive. Themean age of patients was 33.88 years. 20% of them were female and 80% were male. All isolates belonged to the sub genotype D1/ayw2 and genotype D. There were 50 point mutations including 23 (46%) missense and 27 (54%) silent mutations in amino acid level. Twenty three amino acid mutations occurred in different immune epitopes such as 11 (47.82%) in B cell, 6 (26.08%) in T helper and 2 (%8.6) in CTL. The prevalence of mutations in both “a” determinant region and Major Hydrophilic Region (MHR) was 5 (21.73%). Conclusions: Our findings showed that P127T and A70P (Outside of MHR) were the most frequently occurring substitution mutations. P127T, P132T, G130R, and S136Y substitutions placed in the first loop of the “a” determinant and the other substitutions of P142T and D144N occurred in the second loop of “a” determinant. The results of our study showed that most of the mutations occurred in B cell epitopes. The mutation in a surface gene of HBV may be selected by immune pressure or anti-retroviral therapy

    Survey of both hepatitis B virus (HBsAg) and hepatitis C virus (HCV-Ab) coinfection among HIV positive patients

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    <p>Abstract</p> <p>Background</p> <p>HIV, HBVand HCV is major public health concerns. Because of shared routes of transmission, HIV-HCV coinfection and HIV-HBV coinfection are common. HIV-positive individuals are at risk of coinfection with HBV and HCV infections. The prevalence rates of coinfection with HBV and HCV in HIV-patients have been variable worldwide depending on the geographic regions, and the type of exposure.</p> <p>Aim</p> <p>This study aimed to examine HBV and HCV coinfection serologically and determine the shared and significant factors in the coinfection of HIV-positive patients.</p> <p>Methods</p> <p>This descriptive, cross-sectional study was carried out on 391 HIV-positive patients including 358 males and 33 females in Lorestan province, west Iran, to survey coinfection with HBsAg and anti-HCV. The retrospective demographic data of the subjects was collected and the patients' serums were analyzed by ELISA kits including HBsAg and anti-HCV. The collected data was analyzed with SPSS software (15) and Chi-square. Fisher's exact test with 5% error intervals was used to measure the correlation of variables and infection rates.</p> <p>Results</p> <p>The results of the study indicated that the prevalence of coinfection in HIV-positive patients with hepatitis viruses was 94.4% (370 in 391), out of whom 57 (14.5%) cases were HBsAg positive, 282 (72%) cases were anti-HCV positive, and 31 (7.9%) cases were both HBsAg and anti-HCV positive.</p> <p>Conclusion</p> <p>There was a significant correlation between coinfection with HCV and HBV and/or both among HIV-positive patients depending on different variables including sex, age, occupation, marital status, exposure to risk factors.(p < 0.001).</p

    On the effects of convecting entropy waves on the combustor hydrodynamics

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    Entropy waves, as hot spots or density inhomogeneities, can be generated by the flame unsteadiness in combustors. These waves are convected downstream while being annihilated by the flow decay and dispersion mechanisms. This results in the diffusion of the enthalpy of the wave within the base flow. Decaying entropy waves may, therefore, affect the density and viscosity of the base flow and consequently modify the combustor hydrodynamics. Study of such hydrodynamic modifications is the objective of the current numerical study. In particular, the extent of induced changes in the flow is investigated. To do so, some hydrodynamic indices are introduced, in which vorticity magnitude and the angles between the velocity and vorticity vectors are the main parameters. In keeping with the previous studies, entropy waves are inserted at the channel inlet by a linear-increment and exponential-decrement temperature function in a cold flow. A more realistic, and rarely investigated thermal boundary condition of convective type are considered on the walls of the channel. The results show that convection of the entropy waves through the channel noticeably changes the hydrodynamic parameters, such as vorticity vector, helicity and streamlines alignment. This is in contrast with the general notion, which regards entropy waves as passive scalars

    Correction to: The emerging role of probiotics as a mitigation strategy against coronavirus disease 2019 (COVID�19) (Archives of Virology, (2021), 166, 7, (1819-1840), 10.1007/s00705-021-05036-8)

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    Authors would like to correct the error in their publication. The original article has been corrected. 1. Reference 17 is incorrect. The correct one should be �The probiotic Bifidobacterium in the management of Coronavirus: A theoretical basis� https://doi.org/10.1177/2058738420961304. 2. The unnecessary symbol �??� found in text is deleted. © 2021, Springer-Verlag GmbH Austria, part of Springer Nature

    Minimal Size of Cell Assemblies Coordinated by Gamma Oscillations

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    In networks of excitatory and inhibitory neurons with mutual synaptic coupling, specific drive to sub-ensembles of cells often leads to gamma-frequency (25–100 Hz) oscillations. When the number of driven cells is too small, however, the synaptic interactions may not be strong or homogeneous enough to support the mechanism underlying the rhythm. Using a combination of computational simulation and mathematical analysis, we study the breakdown of gamma rhythms as the driven ensembles become too small, or the synaptic interactions become too weak and heterogeneous. Heterogeneities in drives or synaptic strengths play an important role in the breakdown of the rhythms; nonetheless, we find that the analysis of homogeneous networks yields insight into the breakdown of rhythms in heterogeneous networks. In particular, if parameter values are such that in a homogeneous network, it takes several gamma cycles to converge to synchrony, then in a similar, but realistically heterogeneous network, synchrony breaks down altogether. This leads to the surprising conclusion that in a network with realistic heterogeneity, gamma rhythms based on the interaction of excitatory and inhibitory cell populations must arise either rapidly, or not at all. For given synaptic strengths and heterogeneities, there is a (soft) lower bound on the possible number of cells in an ensemble oscillating at gamma frequency, based simply on the requirement that synaptic interactions between the two cell populations be strong enough. This observation suggests explanations for recent experimental results concerning the modulation of gamma oscillations in macaque primary visual cortex by varying spatial stimulus size or attention level, and for our own experimental results, reported here, concerning the optogenetic modulation of gamma oscillations in kainate-activated hippocampal slices. We make specific predictions about the behavior of pyramidal cells and fast-spiking interneurons in these experiments.Collaborative Research in Computational NeuroscienceNational Institutes of Health (U.S.) (grant 1R01 NS067199)National Institutes of Health (U.S.) (grant DMS 0717670)National Institutes of Health (U.S.) (grant 1R01 DA029639)National Institutes of Health (U.S.) (grant 1RC1 MH088182)National Institutes of Health (U.S.) (grant DP2OD002002)Paul G. Allen Family FoundationnGoogle (Firm
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