Studies of some organonitrogen derivatives of chromium and iron

The thesis describes synthetic and structural studies of ketimlno - and amidino - complexes of chromium, and comparisons of their properties with the analagous molybdenum and tungsten derivatives. Studies of an amldino - complex of Iron are also described. The reaction of h(^5)-C(_5)H(_5)Cr(CO)(_3)Br with R(_2)CNLi (R = Ph, p-tolyl, t-butyl) produced green complexes h(^5)-C(_5)H(_5)Cr(CO)(_2)(N:Cr(_2)). Substitution of carbonyl groups in the latter could not be achieved with triphenylphosphine under a variety of conditions. The spectral properties of the complexes are discussed and compared with the corresponding molybdenum and tungsten systems. Reaction of Fe(CO)(_4)I(_2) with (p-tolyl)NLi.CMe:N(p-tolyl) produced an unidentified yellow powder. Subsequent reaction of this powder with alumina produced the orange air-sensitive complex Fe(CO)(_4){(p-tolyl)NH.CMe:N(p-tolyl)}. This complex gave no reaction, with N-bromosuccinimide. Spectral data for the complex is given and discussed. Exploratory investigations of the reaction between h(^5)-C(_5)H(_5)Cr(CO)(_3)Br and RNLi.CR':NR (R = p-tolyl, R' = Me; R = Me, R' = Ph) gave evidence for the formation of a cyclopentadienyl chromium dicarbonyl amidino complex but its instability prevented its isolation. An investigation of the reaction between Ph(_2)CNLi and h(^5)-C(_5)H(_5)cr(CO)(_3)HgBr is also described. A small quantity of h(^5)-C(_5)H(_5)Cr(CO)(_2)(N:CPh(_2)) was detected

Land Use Strategy (LUS) Delivery Evaluation Project : Volume 1: Main Report

Scotland’s first Land Use Strategy (LUS) – Getting the best from our land – was published in March 2011. The LUS is a requirement of the Climate Change (Scotland) Act 2009, highlighting the important contribution that Scottish Ministers expect land use and land management to make towards the climate change agenda in Scotland. The crucial component of the LUS are its ten principles for sustainable land use – the LUS Principles. The LUS Principles are the key mechanism by which the strategic intent of the national level LUS can be translated into regional and local level planning and decision-making, through existing land use delivery mechanisms, to inform action on the ground. The overall aim of the LUS Delivery Evaluation Project therefore was “to evaluate the range of current land use delivery mechanisms, to ascertain their effectiveness in translating the strategic Principles of the LUS into decision-making on the ground”. The evaluation considered eleven case study land use delivery mechanisms ranging from an urban Local Development Plan (LDP) to the Loch Lomond and the Trossachs National Park Partnership Plan

The Limits and Possibilities of Prepaid Water in Urban Africa: Lessons From the Field

This study explores the potential of prepaid meters for serving urban poor communities. It examines eight African countries from the perspective of their communities, as well as from water sector bodies, governments, and other investors

Deep optical imaging of the field of PC1643+4631A&B, I: Spatial distributions and the counts of faint galaxies

We present deep optical images of the PC1643+4631 field obtained at the WHT. This field contains two quasars at redshifts z=3.79 & 3.83 and a cosmic microwave background (CMB) decrement detected with the Ryle Telescope. The images are in U,G,V,R and I filters, and are complete to 25th magnitude in R and G and to 25.5 in U. The isophotal galaxy counts are consistent with the results of Metcalde et al. (1996), Hogg et al. (1997), and others. We find an excess of robust high-redshift Ly-break galaxy candidates with 25.0<R<25.5 compared with the mean number found in the fields studied by Steidel et al. -we expect 7 but find 16 - but we do not find that the galaxies are concentrated in the direction of the CMB decrement. However, we are still not sure of the distance to the system causing the CMB decrement. We have also used our images to compare the commonly used object-finding algorithms of FOCAS and SExtractor: we find FOCAS the more efficient at detecting faint objects and the better at dealing with composite objects, whereas SExtractor's morphological classification is more reliable, especially for faint objects near the resolution limit. More generally, we have also compared the flux lost using isophotal apertures on a real image with that on a noise-only image: recovery of artificial galaxies from the noise-only image significantly overestimates the flux lost from the galaxies, and we find that the corrections made using this technique suffer a systematic error of some 0.4 magnitudes.Comment: 17 pages, 40 figures, submitted to MNRAS, 1 large figure avaliable at ftp://ftp.mrao.cam.ac.uk:/pub/PC1643/paper1.figure18.p

Level banks used to decrease waterlogging can increase salinity

Some farmers have used level W1SALTS banks to control surface zvaters above areas affected by ivaterlogging and salinity. Because the amount of waterlogging has been reduced, crop yields have increased downslope of some banks. However, the banks divert fresh surface water into deeper salty groundwater and, in the long term, worsen salinity. This article details an investigation of the effect of level WIS ALTS banks on saline groundwaters and discusses alternative methods of preventing the waterlogging of saline areas

The Canada-UK Deep Submillimetre Survey: First Submillimetre Images, the Source Counts, and Resolution of the Background

We present the first results of a deep unbiased submillimetre survey carried out at 450 and 850 microns. We detected 12 sources at 850 microns, giving a surface density of sources with 850-micron flux densities > 2.8mJy of of 0.49+-0.16 per square arcmin. The sources constitute 20-30% of the background radiation at 850 microns and thus a significant fraction of the entire background radiation produced by stars. This implies, through the connection between metallicity and background radiation, that a significant fraction of all the stars that have ever been formed were formed in objects like those detected here. The combination of their large contribution to the background radiation and their extreme bolometric luminosities make these objects excellent candidates for being proto-ellipticals. Optical astronomers have recently shown that the UV-luminosity density of the universe increases by a factor of about 10 between z=0 and z=1 and then decreases again at higher redshifts. Using the results of a parallel submillimetre survey of the local universe, we show that both the submillimetre source density and background can be explained if the submillimetre luminosity density evolves in a similar way to the UV-luminosity density. Thus, if these sources are ellipticals in the process of formation, they may be forming at relatively modest redshifts.Comment: 8 pages (LATEX), 6 postscript figures, submitted to ApJ Letter

Rapid assessment of prepaid water systems in Africa

Prepaid water meter systems appear to overcome many of the challenges of supplying water to a range of consumers in Africa. However there are concerns as to the effect on the human right to water as well as on the viability of the approach to water service providers on scale. The paper presents findings from a World Bank study in eight African countries using on-site data collection, key informant interviews, 27 focus groups and 1,180 household surveys in three countries. The study found that customers appreciate the convenience and believe that prepaid systems have enabled them to manage household expenses better, reducing the risk of incurring debt or disconnection. However, although many utilities believe the benefits outweigh the costs, they report that the robustness of prepaid meters varies at present varies considerably, leaving utilities too reliant on technical support from suppliers, which is not always timeously available. Initial capital costs are also relatively high

The Canada-UK Deep Sub-Millimeter Survey II: First identifications, redshifts and implications for galaxy evolution

Identifications are sought for 12 sub-mm sources detected by Eales et al (1998). Six are securely identified, two have probable identifications and four remain unidentified with I_AB > 25. Spectroscopic and estimated photometric redshifts indicate that four of the sources have z < 1, and four have 1 < z < 3, with the remaining four empty field sources probably lying at z > 3. The spectral energy distributions of the identifications are consistent with those of high extinction starbursts such as Arp 220. The far-IR luminosities of the sources at z > 0.5 are of order 3 x 10^12 h_50^-2 L_sun, i.e. slightly larger than that of Arp 220. Based on this small sample, the cumulative bolometric luminosity function shows strong evolution to z ~ 1, but weaker or possibly even negative evolution beyond. The redshift dependence of the far-IR luminosity density does not appear, at this early stage, to be inconsistent with that seen in the ultraviolet luminosity density. Assuming that the energy source in the far-IR is massive stars, the total luminous output from star-formation in the Universe is probably dominated by the far-IR emission. The detected systems have individual star-formation rates (exceeding 300 h_50^-2 M_O yr^-1) that are much higher than seen in the ultraviolet selected samples, and which are sufficient to form substantial stellar populations on dynamical timescales of 10^8 yr. The association with merger-like morphologies and the obvious presence of dust makes it attractive to identify these systems as forming the metal-rich spheroid population, in which case we would infer that much of this activity has occurred relatively recently, at z ~ 2.Comment: 17 pages text + 14 figures. Accepted for publication in the Astrophysical Journal. Gzipped tar file contains one text.ps file for text and tables, one Fig2.jpg file for Fig 2, and 13 Fig*.ps files for the remaining figure

Decentralization : the key to accelerating access to distributed energy services in sub-Saharan Africa?

The decentralization of governance is increasingly considered crucial for delivering development and is being widely adopted in sub-Saharan countries. At the same time, distributed (decentralized) energy systems are increasingly recognized for their role in achieving universal access to energy and are being promoted in sub-Saharan countries. However, little attention has been paid by governments and energy practitioners to the dynamic interrelationships between national and local government and the role of governance decentralization in transitioning to distributed energy systems. This paper traces the complex relationships between accelerated delivery of distributed energy and decentralized local governance systems. The argument is grounded in an exploration of two different approaches to decentralized energy systems governance in Kenya and Malawi. For Kenya, analysis focuses on the energy sector since the adoption of the new decentralized constitution in 2010. In Malawi, it focuses on the involvement of the authors in piloting Local Authority Energy Officers in districts under the decentralization of Malawian energy policy. Our analysis shows that accelerating the speed and scale of implementation for distributed energy systems and enhancing their sustainability and socio-economic impacts is directly linked to the quality of local and national governance structures and their interrelationships. The paper extends existing work in energy and evidence literacy for policy actors by developing an analytical framework, to enable more effective local governance within energy access initiatives in the Global South