Nitrogen Oxide Concentrations in Natural Waters on Early Earth

A key challenge in origins-of-life studies is estimating the abundances of species relevant to the chemical pathways proposed to have contributed to the emergence of life on early Earth. Dissolved nitrogen oxide anions (NO$_{X}^{-}$), in particular nitrate (NO$_{3}^{-}$) and nitrite (NO$_{2}^{-}$), have been invoked in diverse origins-of-life chemistry, from the oligomerization of RNA to the emergence of protometabolism. Recent work has calculated the supply of NO$_{X}^{-}$ from the prebiotic atmosphere to the ocean, and reported steady-state [NO$_{X}^{-}$] to be high across all plausible parameter space. These findings rest on the assumption that NO$_{X}^{-}$ is stable in natural waters unless processed at a hydrothermal vent. Here, we show that NO$_{X}^{-}$ is unstable in the reducing environment of early Earth. Sinks due to UV photolysis and reactions with reduced iron (Fe$^{2+}$) suppress [NO$_{X}^{-}$] by several orders of magnitude relative to past predictions. For pH$=6.5-8$ and $T=0-50^\circ$C, we find that it is most probable that NO$_{X}^{-}$]$<1~\mu$M in the prebiotic ocean. On the other hand, prebiotic ponds with favorable drainage characteristics may have sustained [NO$_{X}^{-}$]$\geq 1~\mu$M. As on modern Earth, most NO$_{X}^{-}$ on prebiotic Earth should have been present as NO$_{3}^{-}$, due to its much greater stability. These findings inform the kind of prebiotic chemistries that would have been possible on early Earth. We discuss the implications for proposed prebiotic chemistries, and highlight the need for further studies of NO$_{X}^{-}$ kinetics to reduce the considerable uncertainties in predicting [NO$_{X}^{-}$] on early Earth.Comment: In review for publication at Geochemistry, Geophysics, and Geosystems (G-cubed). Comments, questions, and criticism solicited; please contact corresponding author at [email protected]. SI at: https://web-cert.mit.edu/sukrit/Public/nox_si.pdf. GitHub at: https://github.com/sukritranjan/no

Integrated Modelling for Understanding Watershed Development Impacts on Social and Biophysical Systems

The intention of watershed development (WD) programs in India is to improve the livelihoods of people and preserve the natural resource base, particularly in areas where water scarcity limits the development potential of rural communities. In practice, there are many complications to implementing WD programs in an effective and equitable way for all people within and between villages in a catchment. Our understanding of the potential implications of a program is often limited by the way in which we investigate the biophysical-social-economic system. Two common failings are (a) not properly considering the importance of the place, scope and scale of a problem and (b) using a disciplinary approach to make conclusions about the system as a whole. This paper discusses how we are addressing these issues as part of an integrated assessment project looking at WD in the state of Andhra Pradesh, India. The multi-disciplinary project team includes agronomists, economists, environmental modellers, groundwater and surface water hydrologists, and social scientists who together are aiming to develop a holistic understanding of the impacts of WD on biophysical, social and economic systems. Key to the project philosophy is the inclusion of government representatives, communities, and non-government organisations (NGOs) in developing the researchers\u27 understanding of the issues and complexities associated with WD and the critical questions that need addressing by the project. An integrated model is being developed that will incorporate crop production water use and hydrological (surface water and groundwater) models in addition to knowledge gained from extensive household surveys in villages in two case study catchments. The household surveys were developed based on discussions with NGOs working with the rural communities in Andhra Pradesh and are being used to examine economic and social outcomes (positive and negative) of WD for households. Measures of equity and resilience are being developed to measure differences in outcomes between villages (e.g. upstream, downstream) and within villages (e.g. income groups, gender, land ownership, etc)

कर्नाटक के देवगढ़ द्वीप में पक्षियोँ की जैवविविधता

कर्नाटक के देवगढ़ द्वीप में पक्षियोँ की जैवविविधत

Forecasting of crop yield using weather parameters–two step nonlinear regression model approach

Concept of the paper is firstly to remove the trend of crop yield and then to develop the forecasting models using detrended yield. Not much work is available or development of forecast models or modelling due to their non-linear behaviour. For that, in this paper, methodology developed for forecasting using nonlinear growth models, which will help in forecasting yield, pest and disease incidences etc with high accuracy. Crop yield forecast models for wheat crop have been developed (using non-linear growth models, linear models and weather indices approach with weekly weather data) for different districts of Uttar Pradesh (UP). Weather Indices (WI) were obtained using above two approaches. Weather indices based regression models were developed using weather indices as independent variables while character under study such as crop yield was used as dependent variable for wheat crop, i.e. two step non-linear forecast model. Technique of forecasting using non-linear approach and using weather indices will enrich the knowledge in developing customized models on forecasting for different types of crops and for different locations. The approach provided reliable yield forecast about two months before harvest

Risk factors for high anti-HHV-8 antibody titers (≥1:51,200) in black, HIV-1 negative South African cancer patients: a case control study

Background: Infection with human herpesvirus 8 (HHV-8) is the necessary causal agent in the development of Kaposi's sarcoma (KS). Infection with HIV-1, male gender and older age all increase risk for KS. However, the geographic distribution of HHV-8 and KS both prior to the HIV/AIDS epidemic and with HIV/AIDS suggest the presence of an additional co-factor in the development of KS. Methods: Between January 1994 and October 1997, we interviewed 2576 black in-patients with cancer in Johannesburg and Soweto, South Africa. Blood was tested for antibodies against HIV-1 and HHV-8 and the study was restricted to 2191 HIV-1 negative patients. Antibodies against the latent nuclear antigen of HHV-8 encoded by orf73 were detected with an indirect immunofluorescence assay. We examined the relationship between high anti-HHV-8 antibody titers (≥1:51,200) and sociodemographic and behavioral factors using unconditional logistic regression models. Variables that were significant at p = 0.10 were included in multivariate analysis. Results: Of the 2191 HIV-1 negative patients who did not have Kaposi's sarcoma, 854 (39.0%) were positive for antibodies against HHV-8 according to the immunofluorescent assay. Among those seropositive for HHV-8, 530 (62.1%) had low titers (1:200), 227 (26.6%) had medium titers (1:51,200) and 97 (11.4%) had highest titers (1:204,800). Among the 2191 HIV-1 negative patients, the prevalence of high anti-HHV-8 antibody titers (≥1:51,200) was independently associated with increasing age (ptrend = 0.04), having a marital status of separated or divorced (p = 0.003), using wood, coal or charcoal as fuel for cooking 20 years ago instead of electricity (p = 0.02) and consuming traditional maize beer more than one time a week (p = 0.02; p-trend for increasing consumption = 0.05) although this may be due to chance given the large number of predictors considered in this analysis. Conclusions: Among HIV-negative subjects, patients with high anti-HHV-8 antibody titers are characterized by older age. Other associations that may be factors in the development of high anti- HHV-8 titers include exposure to poverty or a low socioeconomic status environment and consumption of traditional maize beer. The relationship between these variables and high anti- HHV-8 titers requires further, prospective study

Diagnostic imaging of cervical intraepithelial neoplasia based on hematoxylin and eosin fluorescence

Background Pathological classification of cervical intraepithelial neoplasia (CIN) is problematic as it relies on subjective criteria. We developed an imaging method that uses spectroscopy to assess the fluorescent intensity of cervical biopsies derived directly from hematoxylin and eosin (H&E) stained tissues. Methods Archived H&E slides were identified containing normal cervical tissue, CIN I, and CIN III cases, from a Community Hospital and an Academic Medical Center. Cases were obtained by consensus review of at least 2 senior pathologists. Images from H&E slides were captured first with bright field illumination and then with fluorescent illumination. We used a Zeiss Axio Observer Z1 microscope and an AxioVision 4.6.3-AP1 camera at excitation wavelength of 450–490 nm with emission captured at 515–565 nm. The 32-bit grayscale fluorescence images were used for image analysis. Results We reviewed 108 slides: 46 normal, 33 CIN I and 29 CIN III. Fluorescent intensity increased progressively in normal epithelial tissue as cells matured and advanced from the basal to superficial regions of the epithelium. In CIN I cases this change was less prominent as compared to normal. In high grade CIN lesions, there was a slight or no increase in fluorescent intensity. All groups examined were statistically different. Conclusion Presently, there are no markers to help in classification of CIN I-III lesions. Our imaging method may complement standard H&E pathological review and provide objective criteria to support the CIN diagnosis

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

Performance and Operation of the CMS Electromagnetic Calorimeter

The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

Hard Coral Diversity of Kalpeni Islands, Lakshadweep

Hard Coral Diversity of Kalpeni Islands, Lakshadwee