Nitrates in surface waters, inputs and seasonality: Phase 2

Changes in management practices and agricultural productivity over the past twenty years have lead to nitrate pollution and eutrophication of lakes and rivers. Information on nitrate concentrations and discharge has been collected on the River Frome at East Stoke since 1965, using the same analytical nitrate method so that the results are comparable. These records of weekly spot values of nitrate concentration and daily mean discharges have been analysed for trends and seasonal patterns in both concentration and nitrate loadings. In this extension of our nitrate contract, a new automated method of intensive sampling has been used to monitor short-term variability and to assess how well similar routine (weekly) sampling schemes can represent the true nitrate record

On the polarimetric variability of bright O-type stars

Polarimetric data associated with multi-parameter observational campaigns of selected bright O-type stars and their variable winds, are analysed in relation to the outcomes of the UV and optical spectroscopic studies. For the stars ξ Per and λ Cep, individual measurement uncertainties are Δρ~±0.0002 with nightly mean uncertainties of Δρ~±0.00007. Although variability is apparent on a night-to-night basis, with differences in δρ~0.0002, no correlations are found between these and the periodic behaviours associated with the stellar Si IV and H α lines. Similar polarimetric variability is seen in the data for the standard star ø Cas used as a reference in this observing campaign. It is suggested that all of these low level fluctuations are not intrinsic to the stars but are engendered by structured instrumental polarization in the diffraction pattern and depolarization effects in combination with inconsistent target acquisition and with variable seeing conditions in the Earth's atmosphere. Reassessment of older data for λ Cep from Hayes (1978) also supports this thesis

Simulations of Nonthermal Electron Transport in Multidimensional Flows: Synthetic Observations of Radio Galaxies

We have applied an effective numerical scheme for cosmic-ray transport to 3D MHD simulations of jet flow in radio galaxies (see the companion paper by Jones et al. 1999). The marriage of relativistic particle and 3D magnetic field information allows us to construct a rich set of ``synthetic observations'' of our simulated objects. The information is sufficient to calculate the ``true'' synchrotron emissivity at a given frequency using explicit information about the relativistic electrons. This enables us to produce synchrotron surface-brightness maps, including polarization. Inverse-Compton X-ray surface-brightness maps may also be produced. First results intended to explore the connection between jet dynamics and electron transport in radio lobes are discussed. We infer lobe magnetic field values by comparison of synthetically observed X-ray and synchrotron fluxes, and find these ``inverse-Compton'' fields to be quite consistent with the actual RMS field averaged over the lobe. The simplest minimum energy calculation from the synthetic observations also seems to agree with the actual simulated source properties.Comment: 7 pages, 1 figure; to appear in Life Cycles of Radio Galaxies, ed. J. Biretta et al., New Astronomy Review

Alien Registration- Clarke, Mary (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/22256/thumbnail.jp

Estimating poverty maps from aggregated mobile communication networks

Governments and other organisations often rely on data collected by household surveys and censuses to provide estimates of household poverty and identify areas in most need of regeneration and development investment. However, due to the high cost associated with manual data collection and processing, many developing countries conduct such surveys very infrequently, if at all, and only at a coarse level of spatial granularity. Consequently, it becomes difficult for governments and NGOs to determine where and when to intervene. This thesis addresses this problem by examining the feasibility of deriving up to date and high resolution proxy measurements of poverty from an alternative source of data, namely, Call Detail Records (CDRs), which can be used by organisations to help in decision making. Specifically, we contribute the following: 1. A detailed spatial analysis of economic wealth in two sub-Saharan countries, Senegal and Cote d’Ivoire from which we derive two baseline poverty esti- ˆ mators grounded on concrete usage scenarios. 2. We establish a link between communication patterns and wealth through a simulation-based analysis of information diffusion. We further examine the influence of contextual factors, including data quality issues and economic volatility, on the strength of this relationship. 3. An approach to building wealth prediction models based on features of aggregated CDRs. Features include static and simulation based measures of information access, activity based metrics and econometric inspired metrics. We further perform a comparative analysis of the results of several models in relation to the baseline predictors. We conclude that it is possible to produce proxy poverty or wealth indicators from aggregated CDRs that provide a good level of accuracy, particularly where geographical coverage of the mobile phone network is sufficient. The final outcome of this thesis is a method for developing aggregated CDR-based poverty or wealth models that can be readily implemented anywhere in which there is a need for more up to date and/or finer resolution poverty estimates

Magnetically modulated accretion in T Tauri stars

We examine how accretion on to T Tauri stars may be modulated by a time-dependent `magnetic gate' where the inner edge of the accretion disc is disrupted by a varying stellar field. We show that magnetic field variations on time-scales shorter than 10^5 yr can modulate the accretion flow, thus providing a possible mechanism both for the marked photometric variability of T Tauri stars and for the possible conversion of T Tauri stars between classical and weak line status. We thus suggest that archival data relating to the spectrophotometric variability of T Tauri stars may provide an indirect record of magnetic activity cycles in low-mass pre-main-sequence stars.Comment: LaTeX file (requires mn.sty), 4 pages, no figures or tables. To appear in MNRAS

Diet behaviour among young people in transition to adulthood (18–25 year olds) : a mixed method study

Peer reviewedPublisher PD

Merit - An evaluation tool for 100% renewable energy provision

Islands represent an interesting challenge in terms of energy supply. A great deal of work has been carried out to look at specific aspects of this issue on different islands. Unfortunately, results from one study cannot be easily applied to other islands due to island-specific resources and energy-use profiles. A quantitative evaluation tool (MERIT) is presented here, which is able to match half-hourly energy demands (heat, electricity, hot water and transport) with local supplies. The program examines the energy balance on any scale, from an individual building through to an entire country, thereby providing a powerful and generic aid to decision making. This paper demonstrates the generality and usefulness of MERIT by using it to analyse the options for creating an energy-autonomous community on a typical, small island off the west coast of Scotland. Results are presented showing the feasibility of accomplishing 100% renewable provision on this island using available local resources