Reduction of ferricytochrome c by some free radical agents

Fast pulse radiolysis and kinetic spectroscopy were used to rapidly generate a variety of free radicals in situ and study their reactions with ferricytochrome c in the time range 10(-6) to 1 second. The radicals included t-butanol, which is inert to ferricytochrome c; malate, lactate, and ethanol, which react with it relatively slowly but are completely utilized in reducing it to ferrocytochrome c; and hydrated electrons and hydrogen atoms, which react with it very rapidly but yield ferrocytochrome c only in part, showing intramolecular consecutive reactions and further attack on the ferrocytochrome c protein. From a detailed comparison between malate and hydrogen atoms it is argued that malate reacts directly and selectively with a specific part of the ferricytochrome c surface while hydrogen atoms react with other parts of the protein too, yielding radicals which in part transfer intramolecularly to yield ferrocytochrome c.     

Enzyme from calf thymus degrading the RNA moiety of DNA-RNA Hybrids: effect on DNA-dependent RNA polymerase

An enzyme present in extracts from calf thymus degrades specifically the RNA moiety of DNA-RNA hybrids. Other nucleic acids, such as single- or double-stranded DNA and single- or double-stranded RNA, are not affected to a comparable degree. If prepared free of the hybrid-degrading enzyme, RNA polymerase from calf thymus shows a fivefold increase in activity on denatured DNA as compared to native DNA.     

Limnological effects on a first order stream after wood ash application to a boreal forest catchment in Bispgården,Sweden

In Sweden, whole tree harvest is common practice, possibly leading to the depletion of mineral nutrients. Furthermore, the increased use of forestry residues for heat production has caused an increasingly growing amount of by-product consisting of wood ash. Therefore, the Swedish Forest Agency has recommended wood ash application (WAA) to replace the mineral nutrients removed by whole tree harvesting, as well as a means to mitigate the acidification of boreal forests and surface waters. In a multidisciplinary study during 2003–2006 in Bispgården (Sweden), we have investigated the limnological effects on a first order stream after WAA (conducted in 2004; 3000 kg ha⁻¹) to a 50-ha forested catchment. In general, no significant effects on an annual basis were found for acidification parameters, such as pH, alkalinity and toxic forms of aluminum (Al). There was, however, evidence of an increased pH during the spring flood, accompanied by a simultaneous decrease in the frequency of low pH-values (<5.6). Moreover, alkalinity increased in the years 2005 and 2006 compared to that of 2003, although the increase in 2006 was not statistically different from that in 2005 or 2003. High concentrations of Al repeatedly occurred in the stream, and the WAA did not affect the frequencies of high concentrations of toxic Al forms (>50 μg l⁻¹). The benthic diatom community did not change as a result of the wood ash treatment and the diatom-based index IPS (Indice de PulluoSensibilité) indicated no nutrient enrichment or organic pollution of the stream water. There were, however, indices of elevated concentrations of potassium (K) in the aquatic moss Fontinalis antipyretica and in leaves from Alder (Alnus incana). We conclude that wood ash treatment of a forested catchment with the dose and form of ash applied in this study did not modify the freshwater ecosystem of a first order stream.     

Dissection of a major QTL for seed colour and fibre content in Brassica napus reveals colocalization with candidate genes for phenylpropanoid biosynthesis and flavonoid deposition

A major quantitative trait locus (QTL) influencing seed fibre and colour in Brassica napus was dissected by marker saturation in a doubled haploid (DH) population from the black‐seeded oilseed rape line ‘Express 617’ crossed with a yellow‐seeded B. napus line, ‘1012–98’. The marker at the peak of a sub‐QTL with a strong effect on both seed colour and acid detergent lignin content lay only 4 kb away from a Brassica (H+)‐ATPase gene orthologous to the transparent testa gene AHA10. Near the peak of a second sub‐QTL, we mapped a copy of the key phenylpropanoid biosynthesis gene cinnamyl alcohol dehydrogenase, while another key phenylpropanoid biosynthesis gene, cinnamoyl co‐a reductase 1, was found nearby. In a cross between ‘Express 617’ and another dark‐seeded parent, ‘V8’, Bna.CCR1 was localized in silico near the peak of a corresponding seed fibre QTL, whereas in this case Bna.CAD2/CAD3 lay nearby. Re‐sequencing of the two phenylpropanoid genes via next‐generation amplicon sequencing revealed intragenic rearrangements and functionally relevant allelic variation in the three parents.     

Stocktake study of current fertilisation recommendations across Europe and discussion towards a more harmonised approach

The European Commission has set targets for a reduction in nutrient losses by at least 50% and a reduction in fertiliser use by at least 20% by 2030 while ensuring no deterioration in soil fertility. Within the mandate of the European Joint Programme EJP Soil ‘Towards climate-smart sustainable management of agricultural soils’, the objective of this study was to assess current fertilisation practices across Europe and discuss the potential for harmonisation of fertilisation methodologies as a strategy to reduce nutrient loss and overall fertiliser use. A stocktake study of current methods of delivering fertilisation advice took place across 23 European countries. The stocktake was in the form of a questionnaire, comprising 46 questions. Information was gathered on a large range of factors, including soil analysis methods, along with soil, crop and climatic factors taken into consideration within fertilisation calculations. The questionnaire was completed by experts, who are involved in compiling fertilisation recommendations within their country. Substantial differences exist in the content, format and delivery of fertilisation guidelines across Europe. The barriers, constraints and potential benefits of a harmonised approach to fertilisation across Europe are discussed. The general consensus from all participating countries was that harmonisation of fertilisation guidelines should be increased, but it was unclear in what format this could be achieved. Shared learning in the delivery and format of fertilisation guidelines and mechanisms to adhere to environmental legislation were viewed as being beneficial. However, it would be very difficult, if not impossible, to harmonise all soil test data and fertilisation methodologies at EU level due to diverse soil types and agro-ecosystem influences. Nevertheless, increased future collaboration, especially between neighbouring countries within the same environmental zone, was seen as potentially very beneficial. This study is unique in providing current detail on fertilisation practices across European countries in a side-by-side comparison. The gathered data can provide a baseline for the development of scientifically based EU policy targets for nutrient loss and soil fertility evaluation.     

Livestock predation by endangered African wild dogs (Lycaon pictus) in northern Kenya

Most large mammalian carnivores are in global decline, principally due to conflict with livestock farmers. Because endangered African wild dogs (Lycaon pictus) range widely, often beyond the boundaries of protected areas, they may be particularly exposed to lethal control by farmers, even where nominally protected by reserves. Hence, effectively conserving wild dogs demands resolution of their conflicts with farmers. We investigated livestock depredation by African wild dogs living outside protected areas in northern Kenya. Scat analysis confirmed the distribution of depredation events reported by local farmers, indicating that farmer reports - collated by local Community Liaison Officers - gave a reasonably good index of the true pattern of depredation. Although livestock were abundant throughout the study area, depredation was exceedingly uncommon (approximately one attack per 1000 km² per year) and the costs of tolerating wild dogs were very low (US $3.40/wilddog/year) where wild prey remained, even at low densities. However, where wild prey were seriously depleted, wild dogs killed livestock repeatedly, and the cost of sustaining them rose to US $389/wilddog/year. Hence, although wild dogs had a negligible economic impact in the region, their impact was locally severe. Conservation activities for wild dogs are most likely to be successful if targeted at areas where wild prey remain, and where traditional herding practices have been retained.     

Poverty reduction with irrigation investment: An empirical case study from Tigray, Ethiopia

The regional government of Tigray has invested millions of dollars to develop irrigation schemes as a strategy of poverty reduction. However, there has been limited attempt to analyze whether these investments have attained their stated objectives of poverty reduction and overall socio-economic enhancement. Therefore, we endeavor to: (1) evaluate the impacts of access to small-scale irrigation on farm household's income and poverty status, (2) contribute to the scant literature on irrigation and poverty reduction in Ethiopia, and (3) provide information for policy makers. We examine a representative sample of 613 farm households (331 irrigators and 282 non-irrigators) drawn using three-stage stratified sampling with Probability Proportional to Size. We find that the average income of non-irrigating households is less than that of the irrigating households by about 50%. The overall average income gain due to access to irrigation ranges from 4000 Birr to 4500 Birr per household per annum. We find also that farming income is more important to irrigating households than to non-irrigating households, and off-farm income is negatively related with access to irrigation.     

Long-time 3D CFD modeling of sedimentation with dredging in a hydropower reservoir

Purpose

The purpose of the current study was to present a 3D computational fluid dynamics (CFD) model that can be used to predict long-term (11 years) bed changes in a reservoir due to sedimentation and dredging and that can be done with a reasonable computational time (18 h) on a desktop computer.

Materials and methods

The numerical model solved the Navier-Stokes equations on a 3D non-orthogonal unstructured grid to find the water velocities and turbulence. The convection-diffusion equation for suspended sediment transport was solved to find the sediment deposition pattern. Bed changes were computed and used to adjust the grid over time. Thereby, bed elevations over time were computed. The effect of dredging was also included in the model, and how this affected the bed elevation changes. The main feature of the numerical model enabling a reasonable computational time was implicit numerical methods giving the possibility to use long time steps.

Results and discussion

The results were compared with annually measured bed elevation changes in the reservoir over 11 years. This gave 11 figures of bed elevation changes, due to the combined effect of sedimentation and dredging. Comparing the annually computed and measured bed changes, there was a fair agreement for most of the years. The main deposition patterns were reproduced. The amount of sediments removed in three dredging campaigns were also computed numerically and compared with the measured values. Parameter tests were done for the grid size, fall velocity of the sediments, cohesion, and sediment transport formula. The deviation between computed and measured dredged sediment volumes was less than 16% for all these four parameters/formulas.

Conclusions

The 3D CFD numerical model was able to compute water flow, sediment transport, and bed elevation changes in a hydropower reservoir over a time period of 11 years. Field measurements showed reasonable agreement with the computed bed elevation changes. The results were most sensitive to the sediment particle fall velocity and cohesion of the bed material.