Microbiota of De-Novo Pediatric IBD: Increased Faecalibacterium Prausnitzii and Reduced Bacterial Diversity in Crohn's But Not in Ulcerative Colitis

OBJECTIVES: The gastrointestinal microbiota is considered important in inflammatory bowel disease (IBD) pathogenesis. Discoveries from established disease cohorts report reduced bacterial diversity, changes in bacterial composition, and a protective role for Faecalibacterium prausnitzii in Crohn's disease (CD). The majority of studies to date are however potentially confounded by the effect of treatment and a reliance on established rather than de-novo disease.

METHODS: Microbial changes at diagnosis were examined by biopsying the colonic mucosa of 37 children: 25 with newly presenting, untreated IBD with active colitis (13 CD and 12 ulcerative colitis (UC)), and 12 pediatric controls with a macroscopically and microscopically normal colon. We utilized a dual-methodology approach with pyrosequencing (threshold >10,000 reads) and confirmatory real-time PCR (RT-PCR).

RESULTS: Threshold pyrosequencing output was obtained on 34 subjects (11 CD, 11 UC, 12 controls). No significant changes were noted at phylum level among the Bacteroidetes, Firmicutes, or Proteobacteria. A significant reduction in bacterial alpha-diversity was noted in CD vs. controls by three methods (Shannon, Simpson, and phylogenetic diversity) but not in UC vs. controls. An increase in Faecalibacterium was observed in CD compared with controls by pyrosequencing (mean 16.7% vs. 9.1% of reads, P = 0.02) and replicated by specific F. prausnitzii RT-PCR (36.0% vs. 19.0% of total bacteria, P = 0.02). No disease-specific clustering was evident on principal components analysis.

CONCLUSIONS: Our results offer a comprehensive examination of the IBD mucosal microbiota at diagnosis, unaffected by therapeutic confounders or changes over time. Our results challenge the current model of a protective role for F. prausnitzii in CD, suggesting a more dynamic role for this organism than previously described.

Improving the educational achievement of young people in out-of-home care

A strong link between research and practice is essential to ensure
that the best available evidence gets into the hands of child welfare
practitioners, who are faced with the daunting task of making decisions
about vulnerable children on a daily basis. In 2007, a group of
senior child welfare leaders in the province of Ontario (Canada) created
a research dissemination model that replicated the worldrenowned
UK program, Research in Practice (http://www.rip.org.
uk). Practice and Research Together (PART; www.partontario.org) is
an Ontario consortium of 45 child welfare organizations whose mandate
is to disseminate research to its member agencies, which include
85% of the local child welfare organizations in the province. Each
member pays an annual membership-fee that is based on its size
(Dill & Shera, 2011). A key factor in PART's success has been its ability
to link its program offerings (i.e., webinars, literature reviews, conferences,
and publications) to issues of real-world relevance to child
welfare practitioners and senior leaders. A central and highly anticipated
program offering is PART's annual conference (learning
event). These conferences bring evidence to bear on practice in priority
areas in child welfare.
On May 31 and June 1 and 2, 2011, PART, in collaboration with the
Centre for Research on Educational and Community Services (CRECS)
at the University of Ottawa, co-hosted an international conference in
Ottawa that was focused on improving the educational achievement
of young people in out-of-home care (hereafter, in care). Speakers
from five countries – Canada, USA, Germany, Sweden, and UK – presented
the results of their research at the conference. The speakers
addressed three main topic areas: the disadvantaged socio-political
status of young people in care, many of whom do not complete secondary
or post-secondary education; innovative interventions to improve
their educational outcomes; and the effectiveness of tutoring,
which is the most common educational intervention for young people
in care.

Predicting critical source areas of sediment in headwater catchments

Mitigation of diffuse nutrient and sediment delivery to streams requires successful identification andmanagement of critical source areas within catchments. Approaches to predicting high risk areas forsediment loss have typically relied on structural drivers of connectivity and risk, with little considera-tion given to process driven water quality responses. To assess the applicability of structural metrics topredict critical source areas, geochemical tracing of land use sources was conducted in three headwateragricultural catchments in Co. Down and Co. Louth, Ireland, within a Monte Carlo framework. Outputswere applied to the inverse optimisation of a connectivity model, based on LiDAR DEM data, to assess theefficacy of land use risk weightings to predict sediment source contributions over the 18 month studyperiod in the Louth Upper, Louth Lower and Down catchments. Results of the study indicated sedimentproportions over the study period varied from 6 to 10%, 84 to 87%, 4%, and 2 to 3% for the Down Catch-ment, 79 to 85%, 9 to 17%, 1 to 3% and 2 to 3% in the Louth Upper and 2 to 3%, 79 to 85%, 10 to 17%and 2 to 3% in the Louth Lower for arable, channel bank, grassland, and woodland sources, respectively.Optimised land use risk weightings for each sampling period showed that at the larger catchment scale,no variation in median land use weightings were required to predict land use contributions. However,for the two smaller study catchments, variation in median risk weightings was considerable, which mayindicate the importance of functional connectivity processes at this spatial scale. In all instances, arableland consistently generated the highest risk of sediment loss across all catchments and sampling times.This study documents some of the first data on sediment provenance in Ireland and indicates the needfor cautious consideration of land use as a tool to predict critical source areas at the headwater scale

Voltage and power quality improvement strategy for a DFIG wind turbine during variable wind conditions

This paper presents a voltage and power quality enhancement scheme for a doubly-fed induction generator (DFIG) wind farm during variable wind conditions. The wind profiles were derived considering the measured data at a DFIG wind farm located in Northern Ireland (NI). The aggregated DFIG wind farm model was validated using measured data at a wind farm during variable generation. The voltage control strategy was developed considering the X/R ratio of the wind farm feeder which connects the wind farm and the grid. The performance of the proposed strategy was evaluated for different X/R ratios, and wind profiles with different characteristics. The impact of flicker propagation along the wind farm feeder and effectiveness of the proposed strategy is also evaluated with consumer loads connected to the wind farm feeder. It is shown that voltage variability and short-term flicker severity is significantly reduced following implementation of the novel strategy described.

Optimization of FRT Active Power Performance of a DFIG during Transient Grid Faults

Optimal fault ride-through (FRT) conditions for a doubly-fed induction generator (DFIG) during a transient grid fault are analyzed with special emphasis on improving the active power generation profile. The transition states due to crowbar activation during transient faults are investigated to exploit the maximum power during the fault and post-fault period. It has been identified that operating slip, severity of fault and crowbar resistance have a direct impact on the power capability of a DFIG, and crowbar resistance can be chosen to optimize the power capability. It has been further shown that an extended crowbar period can deliver enhanced inertial response following the transient fault. The converter protection and drive train dynamics have also been analyzed while choosing the optimum crowbar resistance and delivering enhanced inertial support for an extended crowbar period.

Active use of DFIG based Wind Farms for Transient Stability Improvement during Grid Disturbances

The doubly-fed induction generator (DFIG) now represents the dominant technology in wind turbine design. One consequence of this is limited damping and inertial response during transient grid disturbances. A dasiadecoupledpsila strategy is therefore proposed to operate the DFIG grid-side converter (GSC) as a static synchronous compensator (STATCOM) during a fault, supporting the local voltage, while the DFIG operates as a fixed-speed induction generator (FSIG) providing an inertial response. The modeling aspects of the decoupled control strategy, the selection of protection control settings, the significance of the fault location and operation at sub- and super-synchronous speeds are analyzed in detail. In addition, a case study is developed to validate the proposed strategy under different wind penetrations levels. The simulations show that suitable configuration of the decoupled strategy can be deployed to improve system voltage stability and inertial response for a range of scenarios, especially at high wind penetration. The conclusions are placed in context of the practical limitations of the technology employed and the system conditions.

Impact of Wind Generation Mix on Transient Stability for an Interconnected Power System

The rapid growth of wind generation in many European countries is pushing power systems into
uncharted territory. As additional wind generators are installed, the changing generation mix may
impact on power system stability. This paper adopts the New England 39 bus system as a test
system for transient stability analysis. Thermal generator models are based on a likely future plant
mix for existing systems, while varying capacities of fixed-speed induction generators (FSIG) and
doubly-fed induction generators (DFIG) are considered. The main emphasis here has been placed
on the impact of wind technology mix on inter-area oscillations following transient grid
disturbances. In addition, both rotor angle stability and transient voltage stability are examined, and
results are compared with current grid code requirements and standards. Results have shown that
FSIGs can reduce tie-line oscillations and improve damping following a transient disturbance, but
they also cause voltage stability and rotor angle stability problems at high wind penetrations. In
contrast, DFIGs can improve both voltage and rotor angle stability, but their power output
noticeably oscillates during disturbances.

Transient Stability Analysis of a Power System with High Wind Penetration

This paper presents transient stability analysis for a power system with high wind penetration. The transient stability has been evaluated based on two stability criteria: rotor angle stability and voltage stability. A modified IEEE-14 bus system has been used as the main study network and simulations have been conducted at several wind power penetration levels, defined as a fraction of total system generation. A wide range of scenarios have been presented based on the wind farm voltage at the point of connection, i.e. low voltage (LV) distribution level and high voltage (HV) transmission level, and the type of wind generator technology, i.e. fixed speed induction generator (FSIG) and doubly-fed induction generator (DFIG).

The Impact of Wind Farm Power Oscillations on the Irish Power System

The impact of power fluctuations arising from fixed-speed wind turbines on the magnitude and frequency of inter-area oscillations has been investigated. The authors introduced data acquisition equipment to record the power flow on the interconnector between the Northern Ireland and Republic of Ireland systems. Through monitoring the interconnector oscillation using a fast Fourier transform, it was possible to determine the magnitude and frequency of the inter-area oscillation between the two systems. The impact of tower shadow on the output power from a wind farm was analysed using data recorded on site. A case study investigates the effect on the system of the removal of a large fixed-speed wind farm. Conclusions are drawn on the impact that conventional generation and the output from fixed-speed wind farms have on the stability of the Irish power system.

Wind Farm Induced Oscillations

The impact of power fluctuations arising from fixed-speed wind turbines on the magnitude and frequency of inter-area oscillations was investigated. The authors used data acquisition equipment to record the power flow on the interconnector between the Northern Ireland and Republic of Ireland systems. By monitoring the interconnector oscillation using a fast Fourier transform, it was possible to determine the magnitude and frequency of the inter-area oscillation between the Northern Ireland electricity system and that of the electricity supply board. Analysis was preformed to determine the relationship (if any) between the inter-area oscillation and the observed wind power generation at the corresponding time. Subsequently, regression analysis was introduced to model this relationship between the FFT output and the wind power generation. The effect of conventional generators on the magnitude and frequency of the inter-area oscillation was also considered.

Measurement-based Estimation of Wind Farm Inertia

The inertia of fixed-speed wind turbine generators (WTGs) helps to mitigate under-frequency transients, promotes fault ride-through and damps inter-area oscillations. It is therefore important to quantify this inertia. The authors use measured wind farm responses during under-frequency transients to provide this information. They discuss the extent of the data and the criteria used to select certain events for further analysis. The estimation of WTG inertia is based on a induction generator model. The basis of the model will be described. The manner in which the model is applied to estimate the inertia from the measured data is then explained. Finally, the implications of the results for power system operation are assessed.

Frequency Stability Issues for Islanded Power Systems

Frequency stability has not necessarily been a major problem for the majority of power systems in the past. However, for economic and environmental reasons, power systems are now operated closer to stability limits to maximise the use of the existing networks. Therefore, introduction of new, more efficient and renewable generation technologies, and their effect on the power system must be fully understood if a reliable and secure electricity supply is to be maintained. Using the Northern Ireland, and interconnected Republic of Ireland electricity networks as a case study, this paper addresses some of the issues regarding integration and modelling of combined cycle gas turbines (CCGT), and wind turbine generator (WTG) technology on a small islanded power system.

Assessing suspended sediment dynamics in relation to ecological thresholds and sampling strategies in two Irish headwater catchments

Prediction of the impact of suspended sediment on aquatic ecosystems requires adequate knowledge of sediment dynamics in surface waters. Often, studies reporting the response of aquatic biota to suspended sediment are concerned with concentrations, while catchment erosion studies often report sediment delivery as annual loads and yields, making the comparison to documented ecological impacts difficult. Similarly, the European Union Freshwater Fish Directive (FFD) (78/659/EC) stipulates a guideline value of 25mgl which should not be exceeded, with the exception of floods and droughts. In this respect, the significance of suspended sediment in two Irish rivers was assessed using turbidity sensors calibrated for suspended sediment. Sediment yields of 0.07 tonnes (t) hayear and 0.44thayear and annual FFD exceedance frequency of 8.3% and 17.8% were estimated for the two catchments. Contrasts in the frequency of exceedance events between both catchments was observed, yet duration was typically short (

Response of farmland biodiversity to the introduction of bioenergy crops: effects of local factors and surrounding landscape context

The recent growth in bioenergy crop cultivation, stimulated by the need to implement measures to reduce net CO emissions, is driving major land-use changes with consequences for biodiversity and ecosystem service provision. Although the type of bioenergy crop and its associated management is likely to affect biodiversity at the local (field) scale, landscape context and its interaction with crop type may also influence biodiversity on farms. In this study, we assessed the impact of replacing conventional agricultural crops with two model bioenergy crops (either oilseed rape Brassica napus or Miscanthus × giganteus) on vascular plant, bumblebee, solitary bee, hoverfly and carabid beetle richness, diversity and abundance in 50 sites in Ireland. We assessed whether within-field biodiversity was also related to surrounding landscape structure. We found that local- and landscape-scale variables correlated with biodiversity in these agricultural landscapes. Overall, the differences between the bioenergy crops and the conventional crops on farmland biodiversity were mostly positive (e.g. higher vascular plant richness in Miscanthus planted on former conventional tillage, higher solitary bee abundance and richness in Miscanthus and oilseed rape compared with conventional crops) or neutral (e.g. no differences between crop types for hoverflies and bumblebees). We showed that these crop type effects were independent of (i.e. no interactions with) the surrounding landscape composition and configuration. However, surrounding landscape context did relate to biodiversity in these farms, negatively for carabid beetles and positively for hoverflies. Although we conclude that the bioenergy crops compared favourably with conventional crops in terms of biodiversity of the taxa studied at the field scale, the effects of large-scale planting in these landscapes could result in very different impacts. Maintaining ecosystem functioning and the delivery of ecosystem services will require a greater understanding of impacts at the landscape scale to ensure the sustainable development of climate change mitigation measures.

Geophysical and hydrogeological characterisation of the impacts of on-site wastewater treatment discharge to groundwater in a poorly productive bedrock acquifer

Contaminants discharging from on-site wastewater treatment systems (OSWTSs) can impact groundwater quality, threatening human health and surface water ecosystems. Risk of negative impacts becomes elevated in areas of extreme vulnerability with high water tables, where thin unsaturated intervals limit vadose zone attenuation. A combined geophysical/hydrogeological investigation into the effects of an OSWTS, located over a poorly productive aquifer (PPA) with thin subsoil cover, aimed to characterise effluent impacts on groundwater. Groundwater, sampled from piezometers down-gradient of the OSWTS percolation area displayed spatially erratic, yet temporally consistent, contaminant distributions. Electrical resistivity tomography identified an area of gross groundwater contamination close to the percolation area and, when combined with seismic refraction and water quality data, indicated that infiltrating effluent reaching the water table discharged to a deeper more permeable zone of weathered shale resting on more competent bedrock. Subsurface structure, defined by geophysics, indicated that elevated chemical and microbiological contaminant levels encountered in groundwater samples collected from piezometers, down-gradient of sampling points with lower contaminant levels, corresponded to those locations where piezometers were screened close to the weathered shale/competent rock interface; those immediately up-gradient were too shallow to intercept this interval, and thus the more impacted zone of the contaminant plume. Intermittent occurrence of faecal indicator bacteria more than 100 m down gradient of the percolation area suggested relatively short travel times. Study findings highlight the utility of geophysics as part of multidisciplinary investigations for OSWTS contaminant plume characterisation, while also demonstrating the capacity of effluent discharging to PPAs to impact groundwater quality at distance. Comparable geophysical responses observed in similar settings across Ireland suggest the phenomena observed in this study are more widespread than previously suspected.