Hydraulic conductivity assessment of falling head percolation tests used for the design of on-site wastewater treatment systems.

The suitability of a location for an on-site wastewater treatment process (for areas which lack access to centralised wastewater treatment systems) requires an assessment of the permeability of the soil into which the effluent will be discharged. In many jurisdictions this is determined using some type of in-situ percolation test. Falling head percolation tests, which give a value of percolation time (PT) that is empirically related to the notion of hydraulic conductivity, are widely used as they are relatively simple to carry out, but the test does not have a sound theoretical framework and test methods are not standardised internationally. In comparison, the saturated hydraulic conductivity of a soil obtained from a constant head well permeameter test is independent of test conditions, and so is a more suitable metric for design. A database of over 900 falling head tests carried out across a range of different subsoil types in Ireland has been collated, all with the inherent limitations of the existing regulative framework regarding the percolation test and soil texture assessment. These tests were then modelled using Hydrus 2-D numerical modelling simulations to determine equivalent field saturated hydraulic conductivity (Kfs) values and thereby provide a correlation with PT values across the range of subsoil conditions. In addition, falling head tests have been carried out in parallel to constant head permeameter tests in the field and compared against the relationship derived from the broad dataset of simulated results. This revealed an optimal solution by which to determine Kfs from the field permeameter test (using parameters recommended for most structured soils from clays to loams). The trendline based on Irish data was also compared against more generic formulations of the relationship between PT, and Kfs and shown to match closely, particularly the Reynolds (2016) 'unified' methodology. Finally, the Irish threshold PT limits for on-site wastewater treatment have been converted to Kfs values and compared against other international standards.

Spatiotemporal representativeness of air pollution monitoring in Dublin, Ireland.

The importance of selecting appropriate air pollution monitoring sites in a city is vital for accurately reporting air quality, enhancing the quality of high-resolution modelling and informing policy to implement measures to deliver cleaner air in the urban environment. COVID-19 restrictions impacted air quality in urban centres worldwide as reduced mobility led to changes in traffic-related air pollution (TRAP). As such, it offered a unique dataset to examine the spatial and temporal variations in air quality between monitoring stations in Dublin, Ireland. Firstly, an analysis of mobility data showed reductions across almost all sectors after COVID-19 restrictions came into place, which was expected to lower TRAP. In addition, similar changes in air quality were evident to other cities around the world: reductions in fine particulate matter (PM2.5) and nitrogen dioxide (NO2) concentrations and an increase in ozone (O3) concentrations. Average daily and diurnal concentrations for these three pollutants presented more statistically significant spatial and temporal changes during COVID-19 restrictions at monitoring sites with urban or traffic classifications than suburban background sites. Furthermore, substantial reductions in the range of average hourly pollutant concentrations were observed, 79% for PM2.5 and 75% for NO2, with a modest 24% reduction for O3. Correlation analysis of air pollution between monitoring sites and years demonstrated an improvement in the R2 for NO2 concentrations only, suggesting that spatiotemporal homogeneity was most notable for this TRAP due to mobility restrictions during COVID-19. The spatiotemporal representativeness of monitoring stations across the city will change with greener transport, and air quality during COVID-19 can provide a benchmark to support the introduction of new policies for cleaner air.

An evaluation of semidistributed-pipe-network and distributed-finite-difference models to simulate karst systems.

Several different approaches have been developed to model the specific characteristics of karst aquifers, taking account of their inherent complex spatial and temporal heterogeneities. This paper sets out the development of a semidistributed modelling approach for applications in an Irish karst context using urban drainage software. The models have proven to be very useful for different studies, with examples given for the ecohydrology of ephemeral karst lakes, extreme groundwater-flood alleviation, karst network investigation, submarine groundwater discharge, and quantification of different recharge and flow components. The limitations of the approach are also highlighted, in particular not being able to simulate diffuse infiltration and flow paths explicitly across the groundwater catchment. Hence, a more distributed, finite-difference modelling approach using MODFLOW Unstructured Grid (USG) with the newly developed Connected Linear Network (CLN) process is then compared against the semidistributed approach on the same karst catchment. Whilst it has proven difficult to achieve the same levels of model performance in simulating the spring flows in the distributed model compared to the semidistributed model, the ability to interrogate the flow paths at any point on the three-dimensional aquifer is demonstrated, which can give new insights into flows (and potential contaminant transport) through such complex systems. The influence of the proximity of highly transmissive conduits on the flow dynamics through the much-lower transmissive matrix cells in which the network is embedded has been particularly investigated.

Plusieurs approches différentes ont été développées pour modéliser les caractéristiques spécifiques des aquifères karstiques, prenant en compte leurs hétérogénéités spatiales et temporelles associées à leur complexité intrinsèque. Cet article présente le développement d'une approche de modélisation semi-distribuée appliquée à un contexte karstique irlandais en utilisant un logiciel de drainage urbain. Ces modèles se sont avérés très utiles pour différentes études, avec des exemples appliqués à l'écohydrologie de lacs karstiques éphémères, l'atténuation de crues extrêmes liées aux eaux souterraines, à l'étude du réseau karstique, à la décharge des sources sous-marines et à la quantification des différentes composantes aussi bien de la recharge que du débit. Les limites de cette approche sont aussi mises en évidence, avec en particulier l'incapacité de simuler l'infiltration diffuse et les voies d'écoulement de manière explicite au sein du bassin d'alimentation d'eaux souterraines. Par conséquent, une approche de modélisation plus distribuée aux différences finies utilisant le logiciel MODFLOW avec une grille non structurée (USG) intégrant le processus récemment développé de réseau linéaire connecté (CLN) est ensuite comparée à l'approche semi-distribuée appliquée au même bassin karstique. Alors qu'il s'est avéré difficile d'atteindre les mêmes niveaux de performance du modèle concernant la simulation du débit à la source à l'aide du modèle distribué en comparaison au modèle semi-distribué, la possibilité d'examiner les voies d'écoulement en tout point de l'aquifère en 3D est démontrée, ce qui peut donner de nouvelles connaissances sur les écoulements (et le transport potentiel de contaminants) au sein de tels systèmes complexes. L'influence de la proximité de conduits hautement transmissifs sur les écoulements dynamiques au travers des cellules de transmissivité plus faible de la matrice au sein de laquelle le réseau est intégré, a été particulièrement étudiée.

Se han elaborado varios enfoques diferentes para modelar las características específicas de los acuíferos kársticos, teniendo en cuenta sus complejas y propias heterogeneidades espaciales y temporales. En el presente documento se expone la elaboración de un enfoque de modelización semidistribuido para aplicaciones en un contexto kárstico de Irlanda utilizando programas informáticos de drenaje urbano. Los modelos han demostrado ser muy útiles para diferentes estudios, y se dan ejemplos para la ecohidrología de los lagos kársticos efímeros, la mitigación de las inundaciones extremas de aguas subterráneas, la investigación de redes kársticas, la descarga submarina de aguas subterráneas y la cuantificación de diferentes componentes de la recarga y el flujo. También se ponen de relieve las limitaciones del enfoque, en particular el hecho de no poder simular explícitamente la infiltración difusa y las trayectorias de flujo a través de la cuenca de captación de aguas subterráneas. Por lo tanto, un enfoque de modelización de diferencias finitas distribuidas utilizando la red no estructurada (USG) de MODFLOW con el proceso de la Red Lineal Conectada (CLN) recientemente desarrollado se compara entonces con el enfoque semidistribuido en la misma cuenca kárstica. Si bien se ha demostrado que es difícil lograr los mismos niveles de rendimiento del modelo en la simulación de los flujos de manantiales en el modelo distribuido en comparación con el modelo semidistribuido, se demuestra la capacidad de interrogar las trayectorias de los flujos en cualquier punto del acuífero tridimensional, lo que puede dar nuevos conocimientos sobre los flujos (y el transporte de contaminantes potenciales) a través de sistemas tan complejos. Se ha investigado en particular la influencia de la proximidad de conductos altamente transmisivos en la dinámica de los flujos a través de las células de la matriz transmisiva, mucho más bajas, en las que está incorporada la red.

Diversas abordagens diferentes foram desenvolvidas para modelar as características específicas dos aquíferos cársticos, levando em consideração suas complexas heterogeneidades espaciais e temporais inerentes. Este artigo apresenta o desenvolvimento de uma abordagem de modelagem semidistribuída para aplicações em um contexto cárstico irlandês usando software de drenagem urbana. Os modelos provaram ser muito úteis para diferentes estudos, com exemplos dados para a ecohidrologia de lagos cársticos efêmeros, alívio de inundações subterrâneas extremas, investigação de rede cárstica, descarga de água subterrânea submarina e quantificação de diferentes componentes de recarga e fluxo. As limitações da abordagem também são destacadas, em particular não ser capaz de simular infiltração difusa e caminhos de fluxo explicitamente através da captação de água subterrânea. Portanto, uma abordagem de modelagem de diferenças finitas, mais distribuída, usando MODFLOW Unstructured Grid (USG) com o processo de Rede Linear Conectada (RLC) recém-desenvolvido é então comparada com a abordagem semidistribuída na mesma bacia cárstica. Embora tenha se mostrado difícil alcançar os mesmos níveis de desempenho do modelo na simulação dos fluxos de nascente no modelo distribuído em comparação com o modelo semidistribuído, a capacidade de interrogar os caminhos de fluxo em qualquer ponto do aquífero tridimensional é demonstrada, o que pode dar novas percepções sobre os fluxos (e o transporte potencial de contaminantes) por meio de tais sistemas complexos. A influência da proximidade de condutos altamente transmissivos na dinâmica do fluxo através das células da matriz transmissiva muito inferior nas quais a rede está inserida foi investigada particularmente.

An analysis of the spatio-temporal occurrence of anthelmintic veterinary drug residues in groundwater.

Anthelmintics are antiparasitic drugs used to control helminthic parasites such as nematodes and trematodes in animals, particularly those exposed through pasture-based production systems. Even though anthelmintics have been shown to be excreted into the environment in relatively high amounts as unmetabolized drug or transformation products (TPs), there is still only limited information available on their environmental occurrence, particularly in groundwater, which has resulted in them being considered as potential emerging contaminants of concern. A comprehensive study was carried out to investigate the occurrence of 40 anthelmintic residues (including 13 TPs) in groundwaters (and associated surface waters) throughout the Republic of Ireland. The study focused on investigating the occurrence of these contaminants in karst and fractured bedrock aquifers, with a total of 106 sites (88 groundwaters and 18 surface waters) samples during spring 2017. Seventeen anthelmintic compounds consisting of eight parent drugs and nine TPs were detected at 22% of sites at concentrations up to 41 ng L-1. Albendazole and its TPs were most frequently detected residues, found at 8% of groundwater sites and 28% of surface water sites. Multivariate statistical analysis identified several source and pathway factors as being significantly related to the occurrence of anthelmintics in groundwater, however there was an evident localised effect which requires further investigation. An investigation of the temporal variations in occurrence over a 13 month period indicated a higher frequency and concentration of anthelmintics during February/March and again later during August/September 2018, which coincided with periods of increased usage and intensive meteorological events. This work presents the first detections of these contaminants in Irish groundwater and it contributes to broadening our understanding of anthelmintics in the environment. It also provides insight to seasonal trends in occurrence, which is critical for assessing potential future effects and implications of climate change.

An investigation of anticoccidial veterinary drugs as emerging organic contaminants in groundwater.

Intensification of the food production system to meet increased global demand for food has led to veterinary pharmaceuticals becoming a critical component in animal husbandry. Anticoccidials are a group of veterinary products used to control coccidiosis in food-producing animals, with primary prophylactic use in poultry production. Excretion in manure and subsequent land-spreading provides a potential pathway to groundwater. Information on the fate and occurrence of these compounds in groundwater is scant, therefore these substances are potential emerging organic contaminants of concern. A study was carried out to investigate the occurrence of anticoccidial compounds in groundwater throughout the Republic of Ireland. Twenty-six anticoccidials (6 ionophores and 20 synthetic anticoccidials) were analysed at 109 sites (63 boreholes and 46 springs) during November and December 2018. Sites were categorised and selected based on the following source and pathway factors: (a) the presence/absence of poultry activity (b) predominant aquifer category and (c) predominant groundwater vulnerability, within the zone of contribution (ZOC) for each site. Seven anticoccidials, including four ionophores (lasalocid, monensin, narasin and salinomycin) and three synthetic anticoccidials (amprolium, diclazuril and nicarbazin), were detected at 24% of sites at concentrations ranging from 1 to 386 ng L-1. Monensin and amprolium were the two most frequently detected compounds, detected at 15% and 7% of sites, respectively. Multivariate statistical analysis has shown that source factors are the most significant drivers of the occurrence of anticoccidials, with no definitive relationships between occurrence and pathway factors. The study found that the detection of anticoccidial compounds is 6.5 times more likely when poultry activity is present within the ZOC of a sampling point, compared to the absence of poultry activity. This work presents the first detections of these contaminants in Irish groundwater and it contributes to broadening our understanding of the environmental occurrence and fate of anticoccidial veterinary products.

A combined-method approach to trace submarine groundwater discharge from a coastal karst aquifer in Ireland.

Knowledge about the hydraulic connections between submarine groundwater discharge (SGD) and its terrestrial coastal catchment is relevant with regard to the management of marine and coastal waters in karst areas. This study applies different methods and monitoring approaches to trace SGD between the Burren Limestone Plateau and Galway Bay in western Ireland, via an excavated sinkhole shaft and deep conduit. Areas of potential SGD were first delineated based on sea surface temperature anomalies using Landsat satellite images. Two fluorescent dyes and solid wood chips were then used as tracers. Solid wood chips were tested as potential means to circumvent the problem of high dispersion in the sea, impacting on the fluorescent dyes to yield readings below the detection limits. Sampling was conducted at 10 different terrestrial locations and in the sea at Galway Bay. Offshore sampling was conducted in transects over a period of four successive days onboard of a vessel using an automated field fluorometer and a conductivity-temperature-depth sensor. No wood chips were recovered in the sea but both fluorescent dyes were successfully sampled. The estimated travel times are in the order of 100 to 354 m/h, and localised tracer readings correlate well in space and time with low conductivity readings. By confirming hydraulic connections between the two karst features and Galway Bay, the study substantiates the hypothesised importance of Variscan veins with regard to regional groundwater flow in the region.

La connaissance des connexions hydrauliques entre les zones de sorties d'eaux souterraines sous-marines et le bassin terrestre côtier attenant est pertinente pour la gestion des eaux marines et côtières en zones karstiques. Cette étude applique différentes approches méthodologiques et de suivi pour tracer la sortie d'eaux souterraines sous-marines entre le plateau calcaire de Burren et la baie de Galway en Irlande de l'Ouest, via une perte et un conduit profond. Les zones de sorties potentielles d'eaux souterraines sous-marines ont été délimitées dans un premier temps sur la base d'anomalies de température des eaux de mer en utilisant des images satellites Landsat. Deux traceurs fluorescents et des copeaux de bois ont été utilisés comme traceurs. Les copeaux de bois ont été utilisés comme moyen potentiel pour contourner les problèmes de dispersion élevée dans la mer, qui impactent les traceurs fluorescents et engendrent des concentrations sous les limites de détections. L'échantillonnage a été menée sur dix sites différents à terre et en mer dans la baie de Galway. L'échantillonnage en mer e a été mené selon des profils sur une période de quatre jours successifs à bord d'un navire muni d'un fluorimètre de terrain automatique et d'un capteur de conductivité-température-profondeur. Aucun copeau de bois n'a été récupéré en mer, mais les deux traceurs fluorescents ont été échantillonnés avec succès. Les temps de séjour estimés sont de l'ordre de 100 à 354 m/h, et les valeurs de traceurs localisées corrèlent bien en espace et en temps avec les basses valeurs de conductivité électrique. En confirmant les connexions hydrauliques entre les deux phénomènes karstiques et la baie de Galway, l'étude corrobore l'hypothèse de l'importance des veines du cycle varisque sur l'organisation des écoulements régionaux d'eau souterraine dans la région.

El conocimiento de las conexiones hidráulicas entre la descarga submarina de aguas subterráneas (SGD) y su cuenca costera terrestre es relevante para la gestión de las aguas marinas y costeras en las zonas kársticas. Este estudio aplica diferentes métodos y enfoques de monitoreo para el seguimiento de la SGD entre la meseta de caliza de Burren y la bahía de Galway en el oeste de Irlanda, a través de un pozo excavado y un conducto profundo. Las áreas de SGD potenciales fueron delineadas primero basándose en anomalías de la temperatura de la superficie del mar usando imágenes satelitales Landsat. Dos tintes fluorescentes y astillas de madera maciza se utilizaron como trazadores. Las astillas de madera maciza se probaron como medio potencial para eludir el problema de la alta dispersión en el mar, impactando en los colorantes fluorescentes para obtener lecturas por debajo de los límites de detección. El muestreo se llevó a cabo en 10 lugares terrestres diferentes y en el mar en la Bahía de Galway. El muestreo en alta mar se llevó a cabo en transectas durante un período de cuatro días consecutivos a bordo de un buque utilizando un fluorómetro de campo automatizado y un sensor de conductividad-temperatura-profundidad. No se recuperaron astillas de madera en el mar, pero se tomaron muestras exitosas de ambos tintes fluorescentes. Los tiempos de tránsito estimados son del orden de 100 a 354 m/h, y las lecturas del trazador localizadas se correlacionan bien en el espacio y el tiempo con las lecturas de baja conductividad. Al confirmar las conexiones hidráulicas entre las dos características kársticas y la Bahía de Galway, el estudio corrobora la importancia hipotética de las vetas de Variscan con respecto al flujo regional de agua subterránea en la región.

O conhecimento sobre as conexões hidráulicas entre a descarga submarina de águas subterrâneas (DSAS) e sua captação terrestre na costa é relevante no que diz respeito ao gerenciamento de águas marinhas e costeiras em áreas cársticas. Este estudo aplica diferentes métodos e abordagens de monitoramento para rastrear a DSAS entre o platô de calcário de Burren e a baía de Galway, no oeste da Irlanda, por meio de um poço escavado e um conduto profundo. Áreas de potencial DSAS foram primeiramente delineadas com base em anomalias de temperatura da superfície do mar usando imagens do satélite Landsat. Dois corantes fluorescentes e lascas de madeira maciça foram então utilizados como marcadores. Lascas de madeira maciça foram testadas como um meio potencial para contornar o problema de alta dispersão no mar, impactando nos corantes fluorescentes para produzir leituras abaixo dos limites de detecção. A amostragem foi realizada em 10 locais terrestres diferentes e no mar na Baía de Galway. A amostragem fora da costa foi realizada em transectos durante um período de quatro dias sucessivos a bordo de uma embarcação usando um fluorômetro de campo automatizado e um sensor de condutividade-temperatura-profundidade. Nenhuma lasca de madeira foi recuperada no mar, mas os dois corantes fluorescentes foram amostrados com sucesso. Os tempos de viagem estimados são da ordem de 100 a 354 m/h, e as leituras localizadas do traçador se correlacionam bem no espaço e no tempo com as leituras de baixa condutividade. Ao confirmar as conexões hidráulicas entre as duas formações cársticas e a Baía de Galway, o estudo confirma a hipótese da importância das veias variscas em relação ao fluxo regional de águas subterrâneas na região.

A new sensitive method for the simultaneous chromatographic separation and tandem mass spectrometry detection of anticoccidials, including highly polar compounds, in environmental waters.

A sensitive and selective method was developed and validated for the determination of 26 anticoccidial compounds (six ionophores and twenty chemical coccidiostats) in surface and groundwater samples at parts-per-quadrillion (pg L-1) to parts-per-trillion (ng L-1) levels by ultra-high performance liquid chromatography with tandem mass spectrometry detection (UHPLC-MS/MS). A range of different analytical columns and mobile phase compositions were evaluated to enhance selectivity and retention of a number of highly polar and basic anticoccidials along with other non-polar coccidiostats. A combined separation, including these problematic polar compounds, was achieved on a phenyl-hexyl column, by binary gradient elution with water/acetonitrile using ammonium formate and formic acid as additives. The anticoccidial residues were extracted from raw, unfiltered, water samples (250 mL) using polymeric divinylbenzene solid phase extraction (SPE) cartridges, with subsequent elution (methanol:acetonitrile:ethyl acetate, 40:40:20, v/v) and concentration prior to determination. The method recovery (at a concentration representative of realistic expected environmental water concentrations based on literature review) ranged from 81% to 105%. The method was successfully validated for 26 anticoccidials, at four concentration levels, in accordance to Commission Decision 2002/657/EC and SANTE/11813/2017 guidelines. Trueness and precision, under within-laboratory reproducibility conditions, ranged from 88% to 111% and 0.9% to 10.3% respectively.

Quantifying and Numerically Representing Recharge and Flow Components in a Karstified Carbonate Aquifer.

Karstified carbonate aquifers are highly heterogeneous systems characterized by multiple recharge, flow, and discharge components. The quantification of the relative contribution of these components, as well as their numerical representation, remains a challenge. This paper identifies three recharge components in the time and frequency domain. While the analysis in the time domain follows traditional approaches, the analysis of the power spectrum allows frequencies associated with specific spectral coefficients and noise types to be distinguished more objectively. The analysis follows the presented hypothesis that the different frequency-noise components are the result of aquifer heterogeneity transforming the random rainfall input into a sequence of non-Gaussian signals. The distinct signals are then numerically represented in the context of a semidistributed pipe network model in order to simulate recharge, flow, and discharge of an Irish karst catchment more realistically. By linking the power spectra of the modeled recharge components with the spectra of the spring discharge, the information usually gained by classical performance indicators is significantly widened. The modeled spring discharge is well matched in the time and frequency domain, yet the different recharge dynamics explain the signal of the aquifer outlet in different noise domains across the spectrum. This study demonstrates the conjunctive use of frequency analysis in conceptualization of a hydrological system together with modeling and evaluation.

The influence of particle size on the first flush strength of urban stormwater runoff.

The presence of a first flush (FF) of suspended solids (SS) in stormwater runoff has important implications for the design of treatment facilities, as does the particle size of solids. Whilst numerous studies have examined the FF behaviour of SS, few have disaggregated FF trends by particle size. In this study, the FF behaviour of SS was investigated in five size ranges, sampled from an urban stormwater drainage system located in Dublin, Ireland. A weak FF was exhibited in the gross fraction of SS, with just two events from 14 transporting more than 50% of the SS mass in the first 25% of runoff, implying that treatment structures should be capable of removing SS throughout the storm event. In the majority of rain events, the FF strength increased with decreasing particle size, probably related to the lower intensities required to dislodge solids at the onset of rainfall. Although FF strength was correlated with rain event characteristics, prediction intervals were too broad to confirm FF presence based on rainfall data alone. Therefore, the design of smaller treatment volumes based on an assumption of FF must be justified by local monitoring data.

Comprehending the multiple 'values' of green infrastructure - Valuing nature-based solutions for urban water management from multiple perspectives.

The valuation of urban water management practices and associated nature-based solutions (NBS) is highly contested, and is becoming increasingly important to cities seeking to increase their resilience to climate change whilst at the same time facing budgetary pressures. Different conceptions of 'values' exist, each being accompanied by a set of potential measures ranging from calculative practices (closely linked to established market valuation techniques) - through to holistic assessments that seek to address wider concerns of sustainability. Each has the potential to offer important insights that often go well beyond questions of balancing the costs and benefits of the schemes concerned. However, the need to address - and go beyond - economic considerations presents policy-makers, practitioners and researchers with difficult methodological, ethical and practical challenges, especially when considered without the benefit of a broader theoretical framework or in the absence of well-established tools (as might apply within more traditional infrastructural planning contexts, such as the analysis of transport interventions). Drawing on empirical studies undertaken in Sheffield over a period of 10 years, and delivered in partnership with several other European cities and regions, we compare and examine different attempts to evaluate the benefits of urban greening options and future development scenarios. Comparing these different approaches to the valuation of nature-based solutions alongside other, more conventional forms of infrastructure - and indeed integrating both 'green and grey' interventions within a broader framework of infrastructures - throws up some surprising results and conclusions, as well as providing important sign-posts for future research in this rapidly emerging field.

Characterising the variations in ethnic skin colours: a new calibrated data base for human skin.

BACKGROUND: Accurate skin colour measurements are important for numerous medical applications including the diagnosis and treatment of cutaneous disorders and the provision of maxillofacial soft tissue prostheses. METHODS: In this study, we obtained accurate skin colour measurements from four different ethnic groups (Caucasian, Chinese, Kurdish, Thai) and at four different body locations (Forehead, cheek, inner arm, back of hand) with a view of establishing a new skin colour database for medical and cosmetic applications. Skin colours are measured using a spectrophotometer and converted to a device-independent standard colour appearance space (CIELAB) where skin colour is expressed as values along the three dimensions: Lightness L*, Redness a* and Yellowness b*. Skin colour differences and variation are then evaluated as a function of ethnicity and body location. RESULTS: We report three main results: (1) When plotted in a standard colour appearance space (CIELAB), skin colour distributions for the four ethnic groups overlap significantly, although there are systematic mean differences. Between ethnicities, the most significant skin colour differences occur along the yellowness dimension, with Thai skin exhibiting the highest yellowness (b*) value and Caucasian skin the lowest value. Facial redness (a*) is invariant across the four ethnic groups. (2) Between different body locations, there are significant variations in redness (a*), with the forehead showing the highest redness value and the inner arm the lowest. (3) The colour gamut is smallest in the Chinese sample and largest in the Caucasian sample, with the Chinese gamut lying entirely the Caucasian gamut. Similarly, the largest variability in skin tones is found in the Caucasian group, and the smallest in the Chinese group. CONCLUSION: Broadly speaking, skin colour variation can be explained by two main factors: individual differences in lightness and yellowness are mostly due to ethnicity, whereas differences in redness are primarily due to different body locations. Variations in lightness are more idiosyncratic probably reflecting the large influence of environmental factors such as exposure to sun.

Robust retention and transfer of tool construction techniques in chimpanzees (Pan troglodytes).

Long-term memory can be critical to a species' survival in environments with seasonal and even longer-term cycles of resource availability. The present, longitudinal study investigated whether complex tool behaviors used to gain an out-of-reach reward, following a hiatus of about 3 years and 7 months since initial experiences with a tool use task, were retained and subsequently executed more quickly by experienced than by naïve chimpanzees. Ten of the 11 retested chimpanzees displayed impressive long-term procedural memory, creating elongated tools using the same methods employed years previously, either combining 2 tools or extending a single tool. The complex tool behaviors were also transferred to a different task context, showing behavioral flexibility. This represents some of the first evidence for appreciable long-term procedural memory, and improvements in the utility of complex tool manufacture in chimpanzees. Such long-term procedural memory and behavioral flexibility have important implications for the longevity and transmission of behavioral traditions.

Impaired Glucose Tolerance or Newly Diagnosed Diabetes Mellitus Diagnosed during Admission Adversely Affects Prognosis after Myocardial Infarction: An Observational Study.

OBJECTIVE: To investigate the prognostic effect of newly diagnosed diabetes mellitus (NDM) and impaired glucose tolerance (IGT) post myocardial infarction (MI). RESEARCH DESIGN AND METHODS: Retrospective cohort study of 768 patients without preexisting diabetes mellitus post-MI at one centre in Yorkshire between November 2005 and October 2008. Patients were categorised as normal glucose tolerance (NGT n = 337), IGT (n = 279) and NDM (n = 152) on pre- discharge oral glucose tolerance test (OGTT). Primary end-point was the first occurrence of major adverse cardiovascular events (MACE) including cardiovascular death, non-fatal MI, severe heart failure (HF) or non-haemorrhagic stroke. Secondary end-points were all cause mortality and individual components of MACE. RESULTS: Prevalence of NGT, impaired fasting glucose (IFG), IGT and NDM changed from 90%, 6%, 0% and 4% on fasting plasma glucose (FPG) to 43%, 1%, 36% and 20% respectively after OGTT. 102 deaths from all causes (79 as first events of which 46 were cardiovascular), 95 non fatal MI, 18 HF and 9 non haemorrhagic strokes occurred during 47.2 ± 9.4 months follow up. Event free survival was lower in IGT and NDM groups. IGT (HR 1.54, 95% CI: 1.06-2.24, p = 0.024) and NDM (HR 2.15, 95% CI: 1.42-3.24, p = 0.003) independently predicted MACE free survival. IGT and NDM also independently predicted incidence of MACE. NDM but not IGT increased the risk of secondary end-points. CONCLUSION: Presence of IGT and NDM in patients presenting post-MI, identified using OGTT, is associated with increased incidence of MACE and is associated with adverse outcomes despite adequate secondary prevention.

The impact of on-site wastewater from high density cluster developments on groundwater quality.

The net impact on groundwater quality from high density clusters of unsewered housing across a range of hydro(geo)logical settings has been assessed. Four separate cluster development sites were selected, each representative of different aquifer vulnerability categories. Groundwater samples were collected on a monthly basis over a two year period for chemical and microbiological analysis from nested multi-horizon sampling boreholes upstream and downstream of the study sites. The field results showed no statistically significant difference between upstream and downstream water quality at any of the study areas, although there were higher breakthroughs in contaminants in the High and Extreme vulnerability sites linked to high intensity rainfall events; these however, could not be directly attributed to on-site effluent. Linked numerical models were then built for each site using HYDRUS 2D to simulate the attenuation of contaminants through the unsaturated zone from which the resulting hydraulic and contaminant fluxes at the water table were used as inputs into MODFLOW MT3D models to simulate the groundwater flows. The results of the simulations confirmed the field observations at each site, indicating that the existing clustered on-site wastewater discharges would only cause limited and very localised impacts on groundwater quality, with contaminant loads being quickly dispersed and diluted downstream due to the relatively high groundwater flow rates. Further simulations were then carried out using the calibrated models to assess the impact of increasing cluster densities revealing little impact at any of the study locations up to a density of 6 units/ha with the exception of the Extreme vulnerability site.

Solar oxidation and removal of arsenic--Key parameters for continuous flow applications.

Solar oxidation to remove arsenic from water has previously been investigated as a batch process. This research has investigated the kinetic parameters for the design of a continuous flow solar reactor to remove arsenic from contaminated groundwater supplies. Continuous flow recirculated batch experiments were carried out under artificial UV light to investigate the effect of different parameters on arsenic removal efficiency. Inlet water arsenic concentrations of up to 1000 µg/L were reduced to below 10 µg/L requiring 12 mg/L iron after receiving 12 kJUV/L radiation. Citrate however was somewhat surprisingly found to promote a detrimental effect on the removal process in the continuous flow reactor studies which is contrary to results found in batch scale tests. The impact of other typical water groundwater quality parameters (phosphate and silica) on the process due to their competition with arsenic for photooxidation products revealed a much higher sensitivity to phosphate ions compared to silicate. Other results showed no benefit from the addition of TiO2 photocatalyst but enhanced arsenic removal at higher temperatures up to 40 °C. Overall, these results have indicated the kinetic envelope from which a continuous flow SORAS single pass system could be more confidently designed for a full-scale community groundwater application at a village level.

Aromatic-hydroxyl interaction of an alpha-aryl ether lignin model-compound on SBA-15, present at pyrolysis temperatures.

An aromatic alpha-aryl ether compound (a benzyl phenyl ether analogue) was covalently grafted to mesoporous silica SBA-15, to create BPEa-SBA-15. The BPEa-SBA-15 was subjected to successive heating cycles up to 600 °C, with in situ monitoring by DRIFTS. It was found that the toluene moiety coordinates to SBA-15 surface silanol hydroxyl groups via an aromatic-hydroxyl interaction. This interaction is evidenced by a red-shift of the aromatic C-H stretches, as well as a red-shift and broadening of the surface hydroxyl O-H stretches, which are features characteristic of a hydrogen bond. These features remain present during heating until ∼400 °C whereupon the ether linkage of BPEa-SBA-15 is cleaved, accompanied by loss of the toluene moiety.

Rapid diaphragm atrophy following cervical spinal cord hemisection.

A cervical (C2) hemilesion (C2Hx), which disrupts ipsilateral bulbospinal inputs to the phrenic nucleus, was used to study diaphragm plasticity after acute spinal cord injury. We hypothesized that C2Hx would result in rapid atrophy of the ipsilateral hemidiaphragm and increases in mRNA expression of proteolytic biomarkers. Diaphragm tissue was harvested from male Sprague-Dawley rats at 1 or 7 days following C2Hx. Histological analysis demonstrated reduction in cross-sectional area (CSA) of type I and IIa fibers in the ipsilateral hemidiaphragm at 1 but not 7 days. Type IIb/x fibers, however, had reduced CSA at 1 and 7 days. A targeted gene array was used to screen mRNA changes for genes associated with skeletal muscle myopathy and myogenesis; this was followed by qRT-PCR validation. Changes in diaphragm gene expression suggested that profound myoplasticity is initiated immediately following C2Hx including activation of both proteolytic and myogenic pathways. We conclude that an immediate myoplastic response occurs in the diaphragm after C2Hx with atrophy occurring in ipsilateral myofibers within 1 day.

Public information use in chimpanzees (Pan troglodytes) and children (Homo sapiens).

The discernment of resource quality is pertinent to many daily decisions faced by animals. Public information is a critical information source that promotes quality assessments, attained by monitoring others' performance. Here we provide the first evidence, to our knowledge, that chimpanzees (Pan troglodytes) use public information to guide resource selection. Thirty-two chimpanzees were presented with two simultaneous video demonstrations depicting a conspecific acquiring resources at a fast (resource-rich) or slow (resource-poor) rate. Subsequently, subjects selected the resource-rich site above chance expectation. As a comparison, we report evidence of public information use in young children. Investigation of public information use in primates is pertinent, as it can enhance foraging success and potentially facilitate payoff-biased social learning.

A comparison of the suitability of different willow varieties to treat on-site wastewater effluent in an Irish climate.

Short rotation coppiced willow trees can be used to treat on-site wastewater effluent with the advantage that, if planted in a sealed basin and sized correctly, they produce no effluent discharge. This paper has investigated the evapotranspiration rate of four different willow varieties while also monitoring the effects of three different effluent types on each variety. The willow varieties used are all cultivars of Salix viminalis. The effluents applied were primary (septic tank) effluent, secondary treated effluent and rain water (control). The results obtained showed that the addition of effluent had a positive effect on the evapotranspiration. The willows were also found to uptake a high proportion of the nitrogen and phosphorus from the primary and secondary treated effluents added during the first year. The effect of the different effluents on the evapotranspiration rate has been used to design ten full scale on-site treatment systems which are now being monitored.