Intrinsic noise of microRNA-regulated genes and the ceRNA hypothesis

MicroRNAs are small noncoding RNAs that regulate genes post-transciptionally by binding and degrading target eukaryotic mRNAs. We use a quantitative model to study gene regulation by inhibitory microRNAs and compare it to gene regulation by prokaryotic small non-coding RNAs (sRNAs). Our model uses a combination of analytic techniques as well as computational simulations to calculate the mean-expression and noise profiles of genes regulated by both microRNAs and sRNAs. We find that despite very different molecular machinery and modes of action (catalytic vs stoichiometric), the mean expression levels and noise profiles of microRNA-regulated genes are almost identical to genes regulated by prokaryotic sRNAs. This behavior is extremely robust and persists across a wide range of biologically relevant parameters. We extend our model to study crosstalk between multiple mRNAs that are regulated by a single microRNA and show that noise is a sensitive measure of microRNA-mediated interaction between mRNAs. We conclude by discussing possible experimental strategies for uncovering the microRNA-mRNA interactions and testing the competing endogenous RNA (ceRNA) hypothesis.Comment: 32 pages, 11 figure

Analysis of emerging contaminants: A case study of the underground and drinking water samples in Chandigarh, India

The present report deals with the analysis of emerging contaminants and the quality of drinking and underground water supply in Chandigarh, India. A water sampling monitoring and analysis was conducted by collecting a total of 54 samples of underground & drinking water of Chandigarh to analyse the health risk associated with the spread of emerging contaminants in the water sources. The quality of water samples was also assessed by measuring the colour, odour, temperature, pH, electrical conductivity (EC), biological oxygen demand (BOD), dissolved oxygen (DO), total dissolved solids/ salts (TDS) and hardness. For the estimation of the emerging contaminants (Endosulphan (ES) and Hexachlorohexane (HCH)) in the water samples, an extraction procedure was carried out by dispersive liquid-liquid extraction method followed by analysis using gas chromatography-mass spectrometry (GC-MS). The levels of ES and HCH obtained were compared with the drinking water standards of the Bureau of Indian Standards (IS: 10500). The levels of HCH and ES in all the water samples tested were found to be below the detection limit. It cannot be denied that the industrial discharge and other agencies seems to be complying with the regulations. The Initiatives by the Central and State Govt of India seems to have created sensitivity and awareness among the public specifically among the farmers. The limit of detection (LOD) were 1.0 × 10−3 and 2.4 × 10−3 ppm for ES and, HCH respectively. However, some water pollution indicators such as TDS, EC, DO and total hardness were found to exceed the limits specified by the Bureau of Indian Standards (BIS)

Epigenetic Landscapes Explain Partially Reprogrammed Cells and Identify Key Reprogramming Genes

A common metaphor for describing development is a rugged “epigenetic landscape” where cell fates are represented as attracting valleys resulting from a complex regulatory network. Here, we introduce a framework for explicitly constructing epigenetic landscapes that combines genomic data with techniques from spin-glass physics. Each cell fate is a dynamic attractor, yet cells can change fate in response to external signals. Our model suggests that partially reprogrammed cells are a natural consequence of high-dimensional landscapes, and predicts that partially reprogrammed cells should be hybrids that co-express genes from multiple cell fates. We verify this prediction by reanalyzing existing datasets. Our model reproduces known reprogramming protocols and identifies candidate transcription factors for reprogramming to novel cell fates, suggesting epigenetic landscapes are a powerful paradigm for understanding cellular identity

Introduction to the Special Issue – Flows and Practices: The Politics of Integrated Water Resources Management (IWRM) in Southern Africa

For the past two decades, IWRM has been actively promoted by water experts as well as multilateral and bilateral donors who have considered it to be a crucial way to address global water management problems. IWRM has been incorporated into water laws, reforms and policies of southern African nations. This article introduces the special issue 'Flows and Practices: The Politics of IWRM in southern Africa'. It provides a conceptual framework to study: the flow of IWRM as an idea; its translation and articulation into new policies, institutions and allocation mechanisms, and the resulting practices and effects across multiple scales – global, regional, national and local. The empirical findings of the complexities of articulation and implementation of IWRM in South Africa, Zimbabwe, Mozambique, Tanzania and Uganda form the core of this special issue. We demonstrate how Africa has been a laboratory for IWRM experiments, while donors as well as a new cadre of water professionals and students have made IWRM their mission. The case studies reveal that IWRM may have resulted in an unwarranted policy focus on managing water instead of enlarging poor women’s and men’s access to water. The newly created institutional arrangements tended to centralise the power and control of the State and powerful users over water and failed to address historically rooted inequalities.publishedVersio

Beyond Big Bird, Binders, and Bayonets: Humor and Visibility Among Connected Viewers of the 2012 US Presidential Debates

During the 2012 US presidential debates, more than five million connected viewers turned to social media to respond to the broadcast and talk politics with one another. Using a mixed-methods approach, this study examines the prevalence of humor and its relationship to visibility among connected viewers live-tweeting the debates. Based on a content analysis of tweets and accounts, we estimate that approximately one-fifth of the messages sent during the debates consisted of strictly humorous content. Using retweet frequency as a proxy for visibility, we found a positive relationship between the use of humor and the visibility of individual tweets. Not only was humor widespread in the discourse of connected viewers, but humorous messages enjoyed greater overall visibility. These findings suggest a strategic use of humor by political actors seeking greater shares of attention on social media

A Needs Assessment of Screening of Non-Communicable Diseases in Prenatal Care at CHUK and Muhima District Hospital

Introduction: There has been a recent trend of women experiencing delays in management for high-risk pregnancies in Kigali, Rwanda. Physicians at the University Teaching Hospital of Kigali (CHUK) have observed a high incidence of women receiving obstetric care that were not screened appropriately. This points to an inconsistent screening method for non-communicable diseases (NCDs) prior to delivery and lack of streamlined care. The objective of this study is to assess the need for more robust screening of maternal NCDs. Methods: This study, between June 2018-19, is a needs-assessment for the screening of NCDs among pregnant women (n=255) at CHUK. It consists of a retrospective chart review and qualitative interviews. Results: Results thus far indicate that among a sample of pregnant women (n=255) at CHUK, 90.6% received an NCD diagnosis during their care. Almost ¼ (22.7%) of women had an NCD diagnosis during a previous pregnancy. At the time of admission, the average systolic BP was 155.1 (SD = 22.0) and the average diastolic BP was 100.6 (SD = 14.8). A majority of women presented to the district hospital with chief complaints related to preeclampsia or blood pressure. Conclusion: Although analysis is ongoing, these results show that a significant proportion of women with previous high-risk pregnancies experienced delays in care. This leads to negative health outcomes in future pregnancies. Preliminary results indicate a trend of inappropriate management of anticipated possible risk from previously known diagnoses and the need for a streamlined process of referral for maternal NCD cases at CHUK