Evaluating the reliability of point estimates of wetland reference evaporation

The Penman-Monteith formulation of evaporation has been criticised for its reliance upon point estimates so that areal estimates of wetland evaporation based upon single weather stations may be misleading. Typically, wetlands comprise a complex mosaic of land cover types from each of which evaporative rates may differ. The need to account for wetland patches when monitoring hydrological fluxes has been noted. This paper presents work carried out over a wet grassland in Southern England. The significance of fetch on actual evaporation was examined using the approach adopted by Gash (1986) based upon surface roughness to estimate the fraction of evaporation sensed from a specified distance upwind of the monitoring station. This theoretical analysis (assuming near-neutral conditions) reveals that the fraction of evaporation contributed by the surrounding area increases steadily to a value of 77% at a distance of 224 m and thereafter declines rapidly. Thus, point climate observations may not reflect surface conditions at greater distances. This result was tested through the deployment of four weather stations on the wetland. The resultant data suggested that homogeneous conditions prevailed so that the central weather station provided reliable areal estimates of reference evaporation during the observation period March–April 1999. This may be a result of not accounting for high wind speeds and roughness found in wetlands that lead to widespread atmospheric mixing. It should be noted this analysis was based upon data collected during the period March-April when wind direction was constant (westerly) and the land surface was moist. There could be more variation at other times of the year that would lead to greater heterogeneity in actual evaporation.</p> <p style='line-height: 20px;'><b>Keywords: </b>evaporation, Penman-Monteith, automatic weather station, fetch, wetland</p

Rsr1 Palmitoylation and GTPase Activity Status Differentially Coordinate Nuclear, Septin, and Vacuole Dynamics in Candida albicans

Peer reviewedPublisher PD

Estimating evaporation from a wet grassland

International audienceWet grasslands are being restored across the UK and Europe to reinstate their high biodiversity following over 50 years of drainage and conversion to arable agriculture. The water balance of many wet grasslands is dominated by precipitation and evaporation and it is essential to quantify evaporation rates to understand the hydrological functioning of wetlands and the implications for water resources in catchments where wetlands are being restored. This paper considers data from direct measurements of evaporation from the Pevensey Levels wet grassland using the eddy correlation method. Equations are derived to predict actual evaporation using meteorological data on the site or from standard meteorological station observations. It was found that evaporation could be estimated reliably from meteorological variables, such as wind speed, temperature and humidity and by water availability. It was also found that when water availability is high, evaporation is high and may exceed reference evaporation values, raising questions over the deployment of the two-step Penman-Monteith model unless reliable crop coefficients and relative evaporation figures can be determined

Predicting Water Activity for Complex Wastes with Solvation Cluster Equilibria (SCE) - 12042

ABSTRACT Predicting an electrolyte mixture&apos;s water activity, i.e. the ratio of water vapor pressure over a solution with that of pure water, in principle reveals both boiling point and solubilities for that mixture. Better predictions of these properties helps support the ongoing missions to concentrate complex nuclear waste mixtures in order to conserve tank space and improved predictions of water activity will help. A new approach for predicting water activity, the solvation cluster equilibria (SCE) model, uses pure electrolyte water activities to predict water activity for a complex mixture of those electrolytes. An SCE function based on electrolyte hydration free energy and a standard DebyeHückel (DH) charge compression fits each pure electrolyte&apos;s water activity with three parameters. Given these pure electrolyte water activities, the SCE predicts any mixture water activity over a large range of concentration with an additional parameter for each mixture vector, the multinarity. In contrast to ionic strength, which scales with concentration, multinarity is related to the relative proportion of electrolytes in a mixture and can either increase or decrease the water activity prediction over a broad range of concentration for that mixture

Learning in large learning spaces:the academic engagement of a diverse group of students

Teaching larger groups of students is a growing phenomenon in HE and this brings with it, its own challenges not least for the students themselves but also their lecturers. Demographic factors as well as the experiences that characterise us as individuals will impact upon our ability to learn. The pilot study reported here considered the “academic engagement” of a diverse group of students where their course is delivered in large learning environments. As a pilot study, the paper concludes with the identification of two areas which are worthy of further research. Firstly, the study highlighted that mature students were more likely to engage in learning strategies that are associated with surface learning – the binary opposite to which practitioners often strive to achieve. Secondly, the research suggests that students who appear to know their tutors well indicate a preference for study approaches that are likely to develop deeper learning

Distributional Modes for Scalar Field Quantization

We propose a mode-sum formalism for the quantization of the scalar field based on distributional modes, which are naturally associated with a slight modification of the standard plane-wave modes. We show that this formalism leads to the standard Rindler temperature result, and that these modes can be canonically defined on any Cauchy surface.Comment: 15 pages, RevTe

Costs of insensitive acetylcholinesterase insecticide resistance for the malaria vector Anopheles gambiae homozygous for the G119S mutation

<p>Abstract</p> <p>Background</p> <p>The G119S mutation responsible for insensitive acetylcholinesterase resistance to organophosphate and carbamate insecticides has recently been reported from natural populations of <it>Anopheles gambiae </it>in West Africa. These reports suggest there are costs of resistance associated with this mutation for <it>An. gambiae</it>, especially for homozygous individuals, and these costs could be influential in determining the frequency of carbamate resistance in these populations.</p> <p>Methods</p> <p>Life-history traits of the AcerKis and Kisumu strains of <it>An. gambiae </it>were compared following the manipulation of larval food availability in three separate experiments conducted in an insecticide-free laboratory environment. These two strains share the same genetic background, but differ in being homozygous for the presence or absence of the G119S mutation at the <it>ace-1 </it>locus, respectively.</p> <p>Results</p> <p>Pupae of the resistant strain were significantly more likely to die during pupation than those of the susceptible strain. Ages at pupation were significantly earlier for the resistant strain and their dry starved weights were significantly lighter; this difference in weight remained when the two strains were matched for ages at pupation.</p> <p>Conclusions</p> <p>The main cost of resistance found for <it>An. gambiae </it>mosquitoes homozygous for the G119S mutation was that they were significantly more likely to die during pupation than their susceptible counterparts, and they did so across a range of larval food conditions. Comparing the frequency of G119S in fourth instar larvae and adults emerging from the same populations would provide a way to test whether this cost of resistance is being expressed in natural populations of <it>An. gambiae </it>and influencing the dynamics of this resistance mutation.</p

Renewing Criminalized and Hegemonic Cultural Landscapes

The Mafia's long historical pedigree in Mezzogiorno, Southern Italy, has empowered the Mafioso as a notorious, uncontested, and hegemonic figure. The counter-cultural resistance against the mafiosi culture began to be institutionalized in the early 1990s. Today, Libera Terra is the largest civil society organization in the country that uses the lands confiscated from the Mafia as a space of cultural repertoire to realize its ideals. Deploying labor force through volunteer participation, producing biological fruits and vegetables, and providing information to the students on the fields are the principal cultural practices of this struggle. The confiscated lands make the Italian experience of anti-Mafia resistance a unique example by connecting the land with the ideals of cultural change. The sociocultural resistance of Libera Terra conveys a political message through these practices and utters that the Mafia is not invincible. This study draws the complex panorama of the Mafia and anti-Mafia movement that uses the ‘confiscated lands’ as cultural and public spaces for resistance and socio-cultural change. In doing so, this article sheds new light on the relationship between rural criminology and crime prevention policies in Southern Italy by demonstrating how community development practice of Libera Terra changes the meaning of landscape through iconographic symbolism and ethnographic performance

The European Union, borders and conflict transformation: the case of Cyprus

Much of the existing literature on the European Union (EU), conflict transformation and border dynamics has been premised on the assumption that the nature of the border determines EU intervention and the consequences that flow from this in terms of EU impact. The article aims to transcend this literature through assessing how domestic interpretations influence EU border transformation in conflict situations, taking Cyprus as a case study. Moreover, the objective is to fuse the literature on EU bordering impact and perceptions of the EU’s normative projection in conflict resolution. Pursuing this line of inquiry is an attempt to depart from the notion of borders being constructed solely by unidirectional EU logics of engagement or bordering practices to a conceptualization of the border as co-constituted space, where the interpretations of the EU’s normative projections by conflict parties, and the strategies that they pursue, can determine the relative openness of the EU border

The whereabouts of power: politics, government and space

In a world where it has become almost commonplace to talk about power as centralised or distributed, concentrated or diffuse, deterritorialized or dispersed even, it is all too easy to miss the diverse geographies of power that put us in place. The binary talk that forces us to choose between a centred or a decentred view of power, or to shuffle between them in an effort to blur clearly demarcated scales, leaves little room to move beyond defined distances and settled proximities in relation to the exercise of power. In this paper, a more spatially-curious dialogue of power is opened up which foregrounds associational as well as instrumental forms of power which can make a difference to how we act politically