Mineralization of organic contaminants under aerobic and anaerobic conditions in sludge-soil mixtures

Background and Main Features  The mineralization of eight organic chemicals (surfactants, substituted aromatic compounds, di(2-ethylhexyl)phthalate and phenanthrene) was examined in sludge-soil mixtures under aerobic, denitrifying and methanogenic conditions. Results and Discussion  Most of the chemicals were extensively or partially mineralized under aerobic conditions with mineralization half-lives between 1.5 and 12.5 days. Linear tridecyl tetra ethoxylate, di(2-ethylhexyl)phthalate and 2,4-dinitrophenol were also mineralized partially under denitrifying conditions. No mineralization of the chemicals was observed under methanogenic conditions, with the exception of a minor mineralization of linear tridecyl tetraethoxylate. Conclusion  This study indicates that the examined organic chemicals may be rapidly degraded in sludge-amended fields under aerobic conditions, and that some of the chemicals may also be degraded during denitrification. Recommendations and Outlook  When investigating the degradation of sludge-bound chemicals in soil, it is relevant to consider both aerobic and anaerobic soil regimes due to spatial and temporal variations in the redox conditions within sludge and soil. The approach presented in this article may be used for evaluation of the long-term fate of sludge-bound chemicals in soil.     

Effect of flavonoids on stress responses in myotube cultures

Effects of flavonoids on stress response of myotube cultures was studied by monitoring the release of [14C] taurine, leukotriene production, and 2',7'-dichlorodihydroflourescein (DCFH2) oxidation. Stress was induced by hypotonic shock, which was accompanied by cell swelling leading to increased leukotriene production and a concomitant increase in reactive oxygen species and osmolyte release. In this model system, addition of the flavonoids catechin and quercetin decreased leukotriene production, DCFH2 oxidation, and taurine efflux, indicating a reduction of cellular stress. High concentrations of epigallocatechin gallate (EGCG) and tea extract increased leukotriene production and initial DCFH2 oxidation, indicating an increased cellular stress (possibly toxicity). However, taurine efflux was reduced, and also longer exposure time as well as lower concentrations of EGCG and tea reduced DCFH2 oxidation. Trolox and alpha-tocopherol did not significantly affect taurine efflux or leukotriene production, and it was therefore concluded that suppression of these responses was not confined to redox activity in a myotube culture.     

Novel genes continue to enhance population growth in adders (Vipera berus)

In 1999, we published a report on how an introduction of 20 males into a severely inbred and isolated population of adders (Vipera berus) halted its decline towards extinction, induced a profound change in population genetic variability, resulted in a dramatic increase in offspring viability and thus in a rapid increase in numbers. Since the publication of our paper we have received numerous inquiries as to whether we have continued to monitor this population, as this is the case we herein present population demographic data gathered between 1981 and 2003. The population has continued to increase in numbers and in 2003, we collected 39 adult male adders, more than at any time over the 23-year study. Our continued work, hence, lends strong support to the importance of novel genes in enhancing the viability of inbred populations and supports the importance of preserving genetic variability in order to maintain viable wild populations.     

A phenetic analysis of morphological variation in Citrullus lanatus in Namibia

Morphological data recorded from field trials using Citrullus lanatus germplasm collected in Namibia were used to analyse and compare the various morphotypes of this species. The experiment comprised wild types and local landraces as well as commercial cultivars. Cluster analysis supported the indigenous classification system used in Namibia, in which Citrullus types are distinguished based on gross morphology, ecology and usage and grouped into seed, cooking and fresh-eating (watermelon) types. Commercial watermelon cultivars formed a distinct cluster. Wide variation was found within the local types whereas the genetic basis of the commercial type appears to be narrow. The commercial cultivars were most closely related to local watermelon types and more distantly related to the wild types, whereas the cooking melons form an intermediate group.     

Tractor overturn concerns in Iowa: perspectives from the Keokuk county rural health study

Agriculture remains one of the most hazardous industries in the U.S., with tractor overturns producing the greatest number of agricultural machinery-related fatalities. Rollover protective structures (ROPS) and seatbelts effectively reduce tractor overturn deaths. However, a large proportion of tractors in use in American agriculture are older tractors without ROPS and seatbelts. This article describes the tractor-related responses from participants in a population-based study conducted in Keokuk County, Iowa. This study was designed to measure rural and agricultural adverse health and injury outcomes and their respective risk factors. Questionnaires were partially developed from well-documented national surveys. Questions about agricultural machinery use, presence of safety equipment on the machinery, work practices, and attitudes about farm safety were included. Study participants on farms who owned tractors had an average of 3.1 tractors with an average age of 27 years. Only 39% of the 665 tractors had ROPS. Tractor age was associated with the presence of ROPS; 84% of tractors manufactured after 1984 were ROPS-equipped, whereas only 3% of tractors manufactured before 1960 were ROPS-equipped. ROPS-equipped tractors were significantly more common on larger farms and households with higher income. Only 4% of the farmers reported that their tractors had seatbelts and they wore them when operating their tractors. The results of this study support the findings of other studies, which indicate that many older tractors without ROPS and seatbelts remain in use in American agriculture. Until a dramatic reduction in the number of tractors in the U.S. operated without ROPS and seatbelts is achieved, the annual incidence of 120 to 130 deaths associated with tractor overturns will persist.     

Effects of management practices on yield and quality of milk from smallholder dairy units in urban and peri-urban Morogoro,Tanzania

A longitudinal study design was used to assess the management, chemical composition of cows’ milk and quantify the microbial load of raw milk produced at farm level. Data were collected between December 2010 and September 2011 in Morogoro municipality. Milk samples were collected once every month and analysed for butter fat (BF), crude protein (CP), total solids (TS) and solids non-fat (SNF). Total bacterial count (TBC) and coliform counts (CC) were normalized by log transformation. The average milk yield was 7.0 l/day and was not influenced by feeding systems and breeds. Dairy cows owned by people who had no regular income produced more milk than government employees and retired officers. Means of BF, TS, SNF and CP were similar in different feeding systems. Wet season had significantly higher TBC (5.9 log₁₀ cfu/ml) and CC (2.4 log₁₀ cfu/ml) but feeding systems had no effect. Stocking density influenced TBC but not CC. It can be concluded that dairy cows produced low milk yield and its quality was poor.     

Genetic connections between dressage and show-jumping horses in Dutch Warmblood horses

Abstract

During the last decades, the breeding practice within the Dutch Warmblood studbook (KWPN) has resulted in an increasing specialisation of horses into show-jumping (JH) and dressage (DH). The objective of this study was to describe the effect of the specialisation on the connectedness between the subpopulations of JH and DH horses registered by KWPN. The subpopulations comprised 23,800 JH horses and 18,125 DH horses, born between 1995 and 2009. Genetic similarity (GS), genetic pool in common (GC_x) based on the marginal genetic contribution of common ancestors and coefficient of relationship (r) between and within subpopulations were analysed in three periods of time to describe changes in genetic connectedness between subpopulations. A decline in GS (0.97–0.45), GC_0.5 (0.69–0.13) and r (0.018–0.014) in the recent years was observed. Both subpopulations have a common genetic pool; however, if the specialisation process continues, it will result in two unrelated (genetic) groups.     

Effect of Herbicide Treatment on Host Plant Quality for a Leaf-Eating Beetle

The effect of sub-lethal chlorsulfuron treatment of the annual weed Polygonum convolvulus L. on growth and survival of the folivorous beetle Gastrophysa polygoni L. was studied in a controlled environment. Treated and untreated plants were used in whole plant bioassays and in feeding experiments with excised leaves. Direct insect toxicity of the herbicide was studied by use of a Potter Spray Tower. The herbicide was non-toxic to the larvae when applied topically. Larvae fed excised leaves from treated plants did not differ from larvae fed leaves from control plants in terms of developmental time, weight or survival. This suggests that the treatment did not affect the nutritional value of the plant or at least that the beetles could compensate for any such changes. Chlorsulfuron reduced survival of larvae living on whole plants treated with sub-lethal dosages (8 to 67% of the recommended field rate). The mortality of larvae in whole plant experiments was dependent on herbicide dosage and herbivore load. Mortality ranged from approximately 20% on control plants to a maximum of 80% on plants sustaining the highest dosages and herbivore loads. It is argued that the beetles' response to chlorsulfuron-treated plants could be caused by a herbivore-induced plant response enhanced by the action of chlorsulfuron.     

Selective haddock (Melanogrammus aeglefinus) trawling: Avoiding cod (Gadus morhua) bycatch

The critical condition of the North Sea cod stocks has resulted in restrictions on not only cod, but also haddock and other species that are caught together with cod. Thus full exploitation of the haddock stock is unachievable unless cod can be excluded from the haddock catch. We designed a selective trawl based on the behavioral differences between haddock and cod as they enter a trawl, i.e., cod stay close to the seabed whereas haddock rise above it. The trawl's fishing line is raised ～60 cm above the seabed to allow cod to escape beneath the trawl while haddock are retained. To collect the escapees, three sampling bags were attached beneath the raised fishing line. The selective haddock trawl reduced the total catch of cod by 55% during the day and 82% at night, and 99% of the marketable haddock was caught during the day and 89% at night. Cod escape rates were highly length dependent: smaller cod escaped the trawl in greater numbers than did larger individuals. Whiting, saithe, lemon sole, and plaice were included in the analysis.