Excision of damaged bases from transcription intermediates by FPG/NEI superfamily DNA glycosylases

Oxidative lesions are abundant due to constant presence of reactive oxygen species in living cells. Repair of oxidative base lesions is initiated by DNA glycosylases. For example, bacterial Fpg and Nei DNA glycosylases excise oxidized purines and pyrimidines, respectively, from DNA. Their human homologs, NEIL1 and NEIL2, have been reported to show preference towards oxidized lesions in DNA bubbles. From these observations, it had been hypothesized that NEIL proteins may be involved in the repair of lesions in DNA bubbles generated during transcription. However, it is not presently clear how NEILs would behave on bubbles more closely resembling transcription intermediates (e. g., containing the RNA strand), and bacterial homologs Fpg and Nei had never been investigated with bubble substrates. We have studied excision of either 8-oxoguanine (8-oxoG) or 5,6-dihydrouracil (DHU) by E. coli Fpg and Nei and human NEIL1 and NEIL2 from single-strand oligonucleotides, perfect duplexes, bubbles with different number of unpaired bases (6 to 30), Dloops with DNA or RNA and from complexes with RNA polymerase. Fpg, NEIL1 and NEIL2 efficiently excised DHU located inside a bubble. Fpg and NEIL1 was generally more active than NEIL2 in excision of 8-oxoG from ssDNA and bubbles. Nei, on the other hand, was active only on DHU located in dsDNA (either perfect duplex or DNA/DNA D-loop). Fpg and NEIL1 also have shown activity in D-loops with RNA. The activity of Fpg was observed in pre-assembled transcriptional complexes with E. coli RNA polymerase and depended on the position of the lesion in the transcription bubble, possibly reflecting local accessibility of the lesion within the elongation complex

Determinants of Risk Behaviour in Livestock Development Programs: Evidence from South Africa's Kaonafatso Yadikgomo (Kyd) Scheme

Risk plays a significant role in input use decisions and production of output in agricultural production. Understanding farmer risk attitudes and their responses to risk is significant in designing effective intervention programmes. Few studies have tried to identify how the introduction of a livestock programme has tended to influence farmer risk profile. The objective of the study was to highlight the determinants of risk behaviour in participants of a livestock development programme. The study was carried out in KwaZulu-Natal (KZN) Province of South Africa, utilising a purposive sample of 164 respondents who are part of the Kaonafatso Yadikgomo (KYD) Scheme. The cross-sectional survey collected data pertaining to the risk attitudes of the livestock farmers from an attitudinal scale as well as socio-economic and farm biophysical characteristics. Descriptive statistics and multiple linear regression were used to analyse the data. The results show that the livestock farmers were risk loving, with the risk attitude being influenced by the age of household head, monthly household income and experience in rearing cattle at the ð‘ < 0.1 level. Furthermore, the source of income, herd size, reason for slaughtering cattle distance to the nearest water source and access to a dip tank had significant influence of attitude towards risk at the ð‘ < 0.05 level. The study concludes that being part of a livestock development programme tends inflto uence the risk attitudes of the participants as the determinants were against a priori expectations.&nbsp

Multi-objective Optimization of Wind Farm Layouts Under Energy Generation and Noise propagation

Wind farm design deals with the optimal placement of turbines in a wind farm. Past studies have focused on energymaximization, cost-minimization or revenue-maximization objectives. As land is more extensively exploited for onshore wind farms, wind farms are more likely to be in close proximity with human dwellings. Therefore governments, developers, and landowners have to be aware of wind farms’ environmental impacts. After considering land constraints due to environmental features, noise generation remains the main environmental/health concern for wind farm design. Therefore, noise generation is sometimes included in optimization models as a constraint. Here we present continuous-location models for layout optimization that take noise and energy as objective functions, in order to fully characterize the design and performance spaces of the optimal wind farm layout problem. Based on Jensen’s wake model and ISO-9613-2 noise calculations, we used single- and multiobjective genetic algorithms (NSGA-II) to solve the optimization problem. Preliminary results from the biobjective optimization model illustrate the trade-off between energy generation and noise production by identifying several key parts of Pareto frontiers. In addition, comparison of single-objective noise and energy optimization models show that the turbine layouts and the inter-turbine distance distributions are different when considering these objectives individually. The relevance of these results for wind farm layout designers is explored

Agent-based Order Release in Matrix-Structured Assembly Systems

The introduction of new variants and the difficulty of forecasting future market demand and developments aggravate the synchronisation of assembly lines. This ultimately leads to cycle time spreads and thus to efficiency losses, e.g. due to lower employee utilisation. In response, matrix-structured assembly systems have been developed as a concept of cycle time independent flow production. Essential characteristics of this type of assembly systems are the dissolution of both one-dimensionally arranged assembly stations as well as cycle times across assembly stations. In recent years, the focus has been on assembly control for the routing of orders through a matrix-structured assembly system. However, order release strategies have largely been neglected, which means that the actually promised performance of this new organisational form of assembly cannot be fulfilled. An agent-based release decision enables the optimal scheduling of new orders taking into account current information from the assembly system such as station states or the processing progress of orders that have already been released. This work extends and builds on existing agent-based approaches to control matrix-structured assembly systems in regard to order release. This results in a theoretical improvement in key performance indicators such as throughput time and station utilisation. For this purpose, the release process, as well as the associated calculation logics and constraints, are described and the implementation in an environmental model is outlined. An essential part of calculation logics is the prediction of all possible paths and capacity requirements resulting from routing and sequence flexibility. This work contributes to the practical realisation and economic operation of matrix-structured assembly systems

Modelling the spatial-temporal distribution of tsetse (Glossina pallidipes) as a function of topography and vegetation greenness in the Zambezi Valley of Zimbabwe

In this study, we developed a stable and temporally dynamic model for predicting tsetse (Glossina pallidipes) habitat distribution based on a remotely sensed Normalised Difference Vegetation Index (NDVI), an indicator of vegetation greenness, and topographic variables, specifically, elevation and topographic position index (TPI). We also investigated the effect of drainage networks on habitat suitability of tsetse as well as factors that may influence changes in area of suitable tsetse habitat. We used data on tsetse presence collected in North western Zimbabwe during 1998 to develop a habitat prediction model using Maxent (Training AUC = 0.751, test AU = 0.752). Results of the Maxent model showed that the probability of occurrence of tsetse decreased as TPI increased while an increase in elevation beyond 800 m resulted in a decrease in the probability of occurrence. High probabilities (>50%) of occurrence of tsetse were associated with NDVI between high 0.3 and 0.6. Based on the good predictive ability of the model, we fitted this model to environmental data of six different years, 1986, 1991, 1993, 2002, 2007 and 2008 to predict the spatial distribution of tsetse presence in those years and to quantify any trends or changes in the tsetse distribution, which may be a function of changes in suitable tsetse habitat. The results showed that the amount of suitable tsetse habitat significantly decreased (r2 0.799, p = 0.007) for the period 1986 and 2008 due to the changes in the amount of vegetation cover as measured by NDVI over time in years. Using binary logistic regression, the probability of occurrence of suitable tsetse habitat decreased with increased distance from drainage lines. Overall, results of this study suggest that temporal changes in vegetation cover captured by using NDVI can aptly capture variations in habitat suitability of tsetse over time. Thus integration of remotely sensed data and other landscape variables enhances assessment of temporal changes in habitat suitability of tsetse which is crucial in the management and control of tsetse

Anwendung der Infrarotthermografie bei ferkelführenden Sauen

In der Nutztierpraxis gilt die Rektaltemperatur als einer der wichtigsten Indikatoren für die Tiergesundheit. Die rektale Temperaturmessung ist jedoch zeitaufwendig und erfordert direkten Tierkontakt. Die Infrarotthermografie (IR-Thermografie) stellt hingegen eine nichtinvasive, kontaktlose Methode dar, um die Körpertemperatur zu messen. Ein Versuch an Sauen im Abferkelbereich unter Praxisbedingungen hat gezeigt, dass sich die Körperregionen Auge und Ohrrücken zur Erfassung der Körpertemperatur mittels IR-Thermografie gut eignen. Damit kann die IR-Thermografie einen wesentlichen Beitrag zur gezielten Krankheitsprävention und zur Verbesserung des Tierwohls ferkeIführender Sauen leisten.One of the most important disease indicators in livestock is the rectal temperature. This procedure is, compared to the infrared thermography, more time consuming and needs animal contact. The infrared thermography is a contactless and non-invasive method to detect the body temperature. Regarding to animal welfare the infrared thermography is a good method to detect the body temperature. A trial with sows in farrowing crates under practical conditions has shown that the body regions eye and back of the ear are appropriate localisations to record the body temperature using infrared thermography. Therefore the infrared thermography can provide an essential contribution to disease prevention and can improve the welfare of lactating sows

Optimisation of multimedia over wireless IP links via X-layer design: an end-to-end transmission chain simulator

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Lability of DOC transported by Alaskan rivers to the Arctic Ocean

Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 35 (2008): L03402, doi:10.1029/2007GL032837.Arctic rivers transport huge quantities of dissolved organic carbon (DOC) to the Arctic Ocean. The prevailing paradigm is that DOC in arctic rivers is refractory and therefore of little significance for the biogeochemistry of the Arctic Ocean. We show that there is substantial seasonal variability in the lability of DOC transported by Alaskan rivers to the Arctic Ocean: little DOC is lost during incubations of samples collected during summer, but substantial losses (20–40%) occur during incubations of samples collected during the spring freshet when the majority of the annual DOC flux occurs. We speculate that restricting sampling to summer may have biased past studies. If so, then fluvial inputs of DOC to the Arctic Ocean may have a much larger influence on coastal ocean biogeochemistry than previously realized, and reconsideration of the role of terrigenous DOC on carbon, microbial, and food-web dynamics on the arctic shelf will be warranted.This material is based on work supported by the National Science Foundation under grant numbers OPP-0436106, OPP- 0519840, and EAR-0403962, and is a contribution to the Study of Environmental Arctic Change (SEARCH)

Airborne bacterial emission fluxes from manure-fertilized agricultural soil

This is the first study to quantify the dependence on wind velocity of airborne bacterial emission fluxes from soil. It demonstrates that manure bacteria get aerosolized from fertilized soil more easily than soil bacteria, and it applies bacterial genomic sequencing for the first time to trace environmental faecal contamination back to its source in the chicken barn. We report quantitative, airborne emission fluxes of bacteria during and following the fertilization of agricultural soil with manure from broiler chickens. During the fertilization process, the concentration of airborne bacteria culturable on blood agar medium increased more than 600 000-fold, and 1 m3 of air carried 2.9 × 105 viable enterococci, i.e. indicators of faecal contamination which had been undetectable in background air samples. Trajectory modelling suggested that atmospheric residence times and dispersion pathways were dependent on the time of day at which fertilization was performed. Measurements in a wind tunnel indicated that airborne bacterial emission fluxes from freshly fertilized soil under local climatic conditions on average were 100-fold higher than a previous estimate of average emissions from land. Faecal bacteria collected from soil and dust up to seven weeks after fertilization could be traced to their origins in the poultry barn by genomic sequencing. Comparative analyses of 16S rRNA gene sequences from manure, soil and dust showed that manure bacteria got aerosolized preferably, likely due to their attachment to low-density manure particles. Our data show that fertilization with manure may cause substantial increases of bacterial emissions from agricultural land. After mechanical incorporation of manure into soil, however, the associated risk of airborne infection is low