Biology subjects

Gupta, M.

Publications and source records attributed to Gupta, M..

4 recordsLinked to original sources

bioRxiv2018

Transient patterns of functional dysconnectivity in youth with psychosis spectrum symptoms

Psychosis spectrum disorders are conceptualized as neurodevelopmental disorders accompanied by disruption of large-scale functional brain networks. Both static and dynamic dysconnectivity have been described in patients with schizophrenia and, more recently, in help-seeking individuals at clinical high-risk for psychosis. Less is known, however, about developmental aspects of dynamic functional network connectivity (FNC) associated with psychotic symptoms (PS) in the general population. Here, we investigate resting state fMRI data using established dynamic FNC methods in the Philadelphia Neurodevelopmental Cohort (ages 8-22), including 129 participants experiencing PS and 452 participants without PS (non-PS).\n\nApplying a sliding window approach and k-means clustering, 5 dynamic states with distinct whole-brain connectivity patterns were identified. PS-associated dysconnectivity was most prominent in states characterized by synchronization or antagonism of the default mode network (DMN) and cognitive control (CC) domains. Hyperconnectivity between DMN, salience, and CC domains in PS youth only occurred in a state characterized by synchronization of the DMN and CC domains, a state that also becomes less frequent with age. However, dysconnectivity of the sensorimotor and visual systems in PS youth was revealed in other transient states completing the picture of whole-brain dysconnectivity patterns associated with PS.\n\nOverall, state-dependent dysconnectivity was observed in PS youth, providing the first evidence that disruptions of dynamic functional connectivity are present across a broader psychosis continuum.

neuroscience↗

bioRxiv2018

Comparison of two commercial ELISA kits for detection of rubella specific IgM and IgG antibodies

Enzyme linked immunosorbent assay (ELISA) plays an important role in laboratory confirmation of congenital rubella syndrome (CRS), postnatal rubella and seroprevalence studies in different populations. Variation of results are documented for samples tested by different commercial kits. The Enzygnost rubella ELISA, widely used in the WHO network, is expensive and not readily available. In the present study, performance of the Euroimmun ELISA was compared to the Enzygnost ELISA for detection of rubella specific IgM and IgG antibodies.\n\nTwo hundred and eighty five serum samples collected from suspected CRS patients identified through a recently initiated surveillance for CRS at six sentinel hospitals and 435 serum samples from a serosurvey of pregnant women from these sites, were available for testing of rubella specific IgM and IgG antibodies respectively. Qualitative agreement (concordance percentage and Cohens Kappa coefficient -{kappa}) was evaluated for both IgM and IgG assays. Bland - Altman plots were used to assess the difference in quantitative agreement for IgG titers.\n\nGood qualitative agreement between the two ELISA kits was observed for detection of both anti rubella IgM (94.7% agreement and k of 0.86) and IgG (96.3% agreement and k of 0.84). Sensitivity and specificity of Euroimmun assays compared to Enzygnost was 100% and 93.1% for IgM and 95.9% and 100% for IgG respectively. Bland - Altman analysis for paired quantitative results of rubella specific IgG yielded a mean difference of 0.781 IU/ml with majority of values (97.1%) within {+/-} 2 SD of the mean difference. Euroimmun ELISA provided on an average, higher titers as compared to Enzygnost.\n\nOur study findings suggest that Euroimmun ELISA may be considered for detection of rubella specific IgM in suspected CRS cases and rubella specific IgG in surveillance studies.

microbiology↗

bioRxiv2017

Effects of Social Organization, Trap Arrangement and Density, Sampling Scale, and Population Density on Bias in Population Size Estimation Using Some Common Mark-Recapture Estimators

Mark-recapture estimators are commonly used for population size estimation, and typically yield unbiased estimates for most solitary species with low to moderate home range sizes. However, these methods assume independence of captures among individuals, an assumption that is clearly violated in social species that show fission-fusion dynamics, such as the Asian elephant. In the specific case of Asian elephants, doubts have been raised about the accuracy of population size estimates. More importantly, the potential problem for the use of mark-recapture methods posed by social organization in general has not been systematically addressed. We developed an individual-based simulation framework to systematically examine the potential effects of type of social organization, as well as other factors such as trap density and arrangement, spatial scale of sampling, and population density, on bias in population sizes estimated by POPAN, Robust Design, and Robust Design with detection heterogeneity. In the present study, we ran simulations with biological, demographic and ecological parameters relevant to Asian elephant populations, but the simulation framework is easily extended to address questions relevant to other social species. We collected capture history data from the simulations, and used those data to test for bias in population size estimation. Social organization significantly affected bias in most analyses, but the effect sizes were variable, depending on other factors. Social organization tended to introduce large bias when trap arrangement was uniform and sampling effort was low. POPAN clearly outperformed the two Robust Design models we tested, yielding close to zero bias if traps were arranged at random in the study area, and when population density and trap density were not too low. Social organization did not have a major effect on bias for these parameter combinations at which POPAN gave more or less unbiased population size estimates. Therefore, the effect of social organization on bias in population estimation could be removed by using POPAN with specific parameter combinations, to obtain population size estimates in a social species.

ecology↗

bioRxiv2017

Niche construction in evolutionary theory: the construction of an academic niche?

In recent years, fairly far-reaching claims have been repeatedly made about how niche construction, the modification by organisms of their environment, and that of other organisms, represents a vastly neglected phenomenon in ecological and evolutionary thought. The proponents of this view claim that the niche construction perspective greatly expands the scope of standard evolutionary theory and that niche construction deserves to be treated as a significant evolutionary process in its own right, almost at par with natural selection. Claims have also been advanced about how niche construction theory represents a substantial extension to, and re-orientation of, standard evolutionary theory, which is criticized as being narrowly gene-centric and ignoring the rich complexity and reciprocity of organism-environment interactions. We examine these claims in some detail and show that they do not stand up to scrutiny. We suggest that the manner in which niche construction theory is sought to be pushed in the literature is better viewed as an exercise in academic niche construction whereby, through incessant repetition of largely untenable claims, and the deployment of rhetorically appealing but logically dubious analogies, a receptive climate for a certain sub-discipline is sought to be manufactured within the scientific community. We see this as an unfortunate, but perhaps inevitable, nascent post-truth tendency within science.

evolutionary biology↗