Effects of Environmentally Relevant Concentrations of Poultry Litter Associated Contaminates on the Sexual Development of Xenopus laevis

Poultry litter contains high levels of natural sex hormones, nitrogen, phosphorous, and trace amounts of heavy metals. Poultry litter runoff from poultry and farming operations in the Delmarva region can have serious impacts on frog development in the Chesapeake Bay Watershed. In this study, we investigated potential effects of litter compounds on Xenopus laevis development when exposed to environmental levels (0.35 and 0.70 g/L) of litter solution. We found that despite rapid hormone degradation, poultry litter solution still affected X. laevis development. Hormones were also more persistent in the lower poultry litter concentration, leading to even greater effects. Slowed growth and increased female gonadal abnormalities were observed after exposure to 0.35 g/L but not to 0.70 g/L of litter solution, and increased male gonadal abnormalities were observed after treatment to both litter concentrations. The developmental impacts examined in this study may have greater environmental impacts on frog reproduction and survival.

The Impact of Offshore Wind Farms on Marine Ecosystems: A Review Taking an Ecosystem Services Perspective

The rapid increase in renewable energy generation from wind has increased concerns about the impacts that wind arrays have on the marine environment and what these impacts mean for society. One method for identifying the impacts of offshore wind farms (OWFs) on human welfare is through the assessment and valuation of ecosystem services. Using an ecosystem services approach, this paper reviews the impacts of OWFs on the ecosystem services delivered by marine environments. During the construction phase, supporting services such as reduced energy capture and nutrient cycling are changed due to the introduction of hard substrate and the reduction in soft sediment habitat at turbine bases. This may lead to changes in all other ecosystem services, both negative and positive. Quantifying these changes, however, is a challenge partly due to data limitations and a lack of clear understanding of the impacts of OWFs on the marine ecosystems. Scientific effort needs to quantitatively explore the impacts of OWFs on ecosystem functionality and the gathering of data that enables the assessment of changes to ecosystem services. Data needed to better quantify and value the impacts of OWFs on ecosystem services are suggested. The development of methods which integrate socioeconomic valuation of ecosystem services into the evaluation of renewable energy devices compliments efforts in assessing the environmental impacts and should enable a holistic assessment of the impact of renewable energy production and greenhouse gas mitigation technologies on the U. K. carbon footprint.

Development and validation of a lateral flow device for the detection of nicarbazin contamination in poultry feeds

Concentrations of the coccidiostat nicarbazin as low as 2 mg/kg in feed can result in violative drug residues arising in poultry liver. A lateral flow device (LFD) was developed for the detection of contaminating concentrations of nicarbazin following solvent extraction of poultry feeds. Test results, as determined by both visual and instrumental measurement, are available within minutes. For 22 feed samples, nicarbazin-free and fortified at 2 mg/kg, the % relative inhibition ranged from 0 to 45% and from 53 to 85%, respectively. Nicarbazin contamination at the critical concentration (2 mg/kg) can be determined in all cases providing the sampling is representative. A wide range of feed samples taken at a mill that incorporated nicarbazin into poultry feed were analyzed. Data generated for these samples by both the LFDs and a mass spectrometric method were compared, and a significant correlation was achieved.

Dendrochronology and Deer Park Farms

This chapter examines some aspects of the environmental
context for the constructional activity observed at Deer
Park Farms (DPF). This can be done at several levels by
observing what dendrochronology suggests in terms of
environment and environmental change across the period
from around AD 500 to 1000. Looking at the broad sweep
of tree growth across the period, something not previously
attempted, we can make comparisons between tree
growth in Ireland and elsewhere in Europe. We can study
abrupt events in the records and draw on information
from other sources in an attempt to paint a picture of the
period against which to view the constructional activity
on the site itself. It is worth remarking that there is no
blueprint for this work. Most of the information used has
only recently been produced and it is largely independent
of conventional history.

Coordinated Control of DFIG and FSIG-based Wind Farms under Unbalanced Grid Conditions

This paper investigates the control and operation of doubly-fed induction generator (DFIG) and fixed-speed induction generator (FSIG) based wind farms under unbalanced grid conditions. A DFIG system model suitable for analyzing unbalanced operation is developed, and used to assess the impact of an unbalanced supply on DFIG and FSIG operation. Unbalanced voltage at DFIG and FSIG terminals can cause unequal heating on the stator windings, extra mechanical stresses and output power fluctuations. These problems are particularly serious for the FSIG-based wind farm without a power electronic interface to the grid. To improve the stability of a wind energy system containing both DFIG and FSIG based wind farms during network unbalance, a control strategy of unbalanced voltage compensation by the DFIG systems is proposed. The DFIG system compensation ability and the impact of transmission network impedance are illustrated. The simulation results implemented in Matlab/Simulink show that the proposed DFIG control system improves not only its own performance, but also the stability of the FSIG system with the same grid connection point during network unbalance.