Ancient lakes of the Sahara

As a result of climate change over the past 5000 years the Sahara changed from savannah to a desert landscape. The beds of ancient lakes are home to snail shells and the petrified roots of trees and shrubs. Examples of human occupation can also be seen in the form of fireplaces and discarded tools. Examination of the geological history of these sites can give a clearer picture of how the climate changed and how humans coped with these changes.

The Palaeolithic Rivers of Southwest Britain

The Palaeolithic Rivers of Southwest Britain (PRoSWeB) project synthesises the archaeological evidence for the Lower and Middle Palaeolithic occupation of south-west Britain (c. 500,000 - 40,000 BP), with a principal focus upon the archaeological and geological potential of the region's Middle Pleistocene fluvial environments. South-west Britain was defined as the region west of the headwaters of the Rivers Frome and Piddle and south-west of the River Avon.

Terrestrial implications for the maritime geoarchaeological resource: A view from the Lower Palaeolithic

Stone tools and faunal remains have been recovered from the English Channel and the North Sea through trawling, dredging for aggregates, channel clearance, and coring. These finds highlight the potential for a maritime Lower Palaeolithic archaeological resource. It is proposed here that any Lower Palaeolithic artefacts, faunal remains, and sediments deposited in the maritime zone during dry, low-stand phases were once (and may still be) contextually similar to their counterparts in the terrestrial Lower Palaeolithic records of north-western Europe. Given these similarities, can interpretive models and analytical frameworks developed for terrestrial archaeology be profitably applied to an assessment of the potential value of any maritime resource? The terrestrial geoarchaeological resource for the Lower Palaeolithic is dominated by artefacts and ecofacts that have been fluvially reworked. The spatio-temporal resolution of these data varies from entire river valleys and marine isotope stages to river channel gravel bar surfaces and decadal timescales, thus supporting a variety of questions and approaches. However, the structure of the terrestrial resource also highlights two fundamental limitations in current maritime knowledge that can restrict the application of terrestrial approaches to any potential maritime resource: (i) how have the repetitive transgressions and regressions of the Middle and Late Pleistocene modified the terrace landforms and sediments associated with the river systems of the English Channel and southern North Sea basins?; and (ii) do the surviving submerged terrace landforms and fluvial sedimentary deposits support robust geochronological models, as is the case with the classical terrestrial terrace sequences? This paper highlights potential approaches to these questions, and concludes that the fluvial palaeogeography, Pleistocene fossils, and potential Lower Palaeolithic artefacts of the maritime geoarchaeological resource can be profitably investigated in future as derived, low-resolution data sets, facilitating questions of colonisation, occupation, demography, and material culture.

A record of Holocene climate change from lake geochemical analyses in southeastern Arabia

Lacustrine sediments from southeastern Arabia reveal variations in lake level corresponding to changes in the strength and duration of Indian Ocean Monsoon (IOM) summer rainfall and winter cyclonic rainfall. The late glacial/Holocene transition of the region was characterised by the development of mega-linear dunes. These dunes became stabilised and vegetated during the early Holocene and interdunal lakes formed in response to the incursion of the IOM at approximately 8500 cal yr BP with the development of C3 dominated savanna grasslands. The IOM weakened ca. 6000 cal yr BP with the onset of regional aridity, aeolian sedimentation and dune reactivation and accretion. Despite this reduction in precipitation, the take was maintained by winter dominated rainfall. There was a shift to drier adapted C4 grasslands across the dune field. Lake sediment geochemical analyses record precipitation minima at 8200, 5000 and 4200 cal yr BP that coincide with Bond events in the North Atlantic. A number of these events correspond with changes in cultural periods, suggesting that climate was a key mechanism affecting human occupation and exploitation of this region. (c) 2006 University of Washington. All rights reserved.

Ancient lakes of the Sahara

As a result of climate change over the past 5000 years the Sahara changed from savannah to a desert landscape. The beds of ancient lakes are home to snail shells and the petrified roots of trees and shrubs. Examples of human occupation can also be seen in the form of fireplaces and discarded tools. Examination of the geological history of these sites can give a clearer picture of how the climate changed and how humans coped with these changes.

UK commercial property lease structures: Landlord and tenant mismatch

UK commercial property lease structures have come under considerable scrutiny during the past decade since the property crash of the early 1990s. In particular, tenants complained that the system was unfair and that it has blocked business change. Government is committed, through its 2001 election manifesto, to promote flexibility and choice in the commercial property lettings market and a new voluntary Commercial Leases Code of Practice was launched in April 2002. This paper investigates whether occupiers are being offered the leases they require or whether there is a mismatch between occupier requirements and actual leases in the market. It draws together the substantial data now available on the actual terms of leases in the UK and surveys of corporate occupiers' attitude to their occupation requirements. Although the data indicated that UK leases have become shorter and more diverse since 1990, this is still not sufficient to meet the current requirements of many corporate occupiers. It is clear that the inability to manage entry and exit strategies is a major concern to occupiers. Lease length is the primary concern of tenants and a number of respondents comment on the mismatch between lease length in the UK and business planning horizons. The right to break and other problems with alienation clauses also pose serious difficulties for occupiers, thus reinforcing the mismatch. Other issues include repairing and insuring clauses and the type of review clause. There are differences in opinion between types of occupier. In particular, international corporate occupiers are significantly more concerned about the length of lease and the incidence of break clauses than national occupiers and private-sector tenants are significantly more concerned about leasing in general than public-sector occupiers. Proposed solutions by tenants are predictable and include shorter leases, more frequent breaks and relaxation of restrictions concerning alienation and other clauses. A significant number specify that they would pay more for shorter leases and other improved terms. Short leases would make many of the other terms more acceptable and this is why they are the main concern of corporate occupiers. Overall, the evidence suggests that there continues to be a gap between occupiers' lease requirements and those currently offered by the market. There are underlying structural factors that act as an inertial force on landlords and inhibit the changes which occupiers appear to want. Nevertheless, the findings raise future research questions concerning whether UK lease structures are a constraining factor on UK competitiveness.

The Royal Army Education Corps in the Gulf Conflict of 1990-91

The official history of the Royal Army Education Corps' involvement in Operation 'Desert Storm', the liberation of Kuwait from Iraqi occupation in 1991, their roles including prisoner of war interrogation, psychological operations, IT services and acting as interpreters for senior officers.

Forces information and media services in Operation Granby 1990-91

The paper looks at the setting up of media services for British Army forces engaged in Operation Granby, the British participation in Operation Desert Storm, the liberation of Kuwait from Iraqi occupation in 1991. In particular, the piece focuses on the creation of a force newspaper and radio station.There is far more involved in the organisation of modern war than simply battles themselves One aspect is the importance of creating and maintaining morale, which can be achieved in a number of ways, especially by keeping troops informed of their progress, purpose and mission as operations unfold. This was specifically recognised by commanders in the Gulf War, who ensured the smooth transmission of information by the provision of media services for forces personnel throughout the War. Here S J Anglim concentrates on the difficulties inherent in setting up and running the Gulf Forces newspaper, The Sandy Times, a Radio service and producing video reviews, all of which played their part in ensunng high morale. He concludes that there are lessons to be learnt and implemented for the success of any future conflicts.

Free-range village chickens on the Accra plains, Ghana: Their contribution to households

A cross-sectional survey investigating the contribution of free-range village chickens to household economies was carried out in four administrative districts within 60km of Accra. Answers were provided by 101 men and 99 women. Nearly all respondents claimed to keep chickens for meat, with a far smaller percentage claiming to keep them for egg production. Over 80% of respondents kept chickens to supplement their incomes. The proportion of the flock eaten varied between administrative areas (p=0.009 and p=0.027), although this was possibly a consequence of differences in consumption patterns between occupation of the respondent, land area cultivated and flock size. The proportion of chickens sold varied as a result of differences in flock size (p=0.013), the proportion sold increasing with number of birds in the flock. Respondents generally agreed that chickens could be sold without difficulty. A majority of chicken sales were from the farm gate, directly to consumers or traders. Sales were on demand or when the owner needed money. Money from the sale was kept by the owner of the chicken and the money was spent on personal needs. The proportion of the flock sold varied between administrative areas (p=0.025) and occupation of the respondent (p=0.040). Respondents describing animal production as their main occupation tended to have greater reliance on chicken sales for their income. Consideration is given to estimating the offtake from the flock and the financial contribution to the household.

An investigation into factors affecting the occupational choices of nominated farm heirs in Ireland

The resilience of family farming is an important feature of the structure of the farming industry in many countries, due largely to the 'smooth' succession of farms from one generation to the next. The stability of this structure is now threatened by the widening gap between the income expected from farming when compared with non-farming occupations in an economy like Ireland, operating at almost full employment. Nominated farm heirs are increasingly unlikely to choose full-time farming as their preferred occupation. To identify the factors that affect this occupational choice, a multinomial logit model is developed and applied to Irish data to examine the farm, economic and personal characteristics that influence a nominated heir's decision to enter farming as opposed to some non-farming occupation. The results show a significant negative relationship between higher education and the choice of full-time farming as an occupation. The interdependence between education and occupational choices is further explored using a bivariate probit model. The main findings are: the occupational choice and the decision to continue with higher education are made jointly; the nominated heirs on more profitable farms are less likely to pursue tertiary education and therefore more likely to enter full-time farming. The model developed is sufficiently general for studying the phenomenon of succession on farms.

The distribution of species diversity across a flora's component lineages: dating the Cape's 'relicts'

The Cape Floristic Region is exceptionally species-rich both for its area and latitude, and this diversity is highly unevenly distributed among genera. The modern flora is hypothesized to result largely from recent (post-Oligocene) speciation, and it has long been speculated that particular species-poor lineages pre-date this burst of speciation. Here, we employ molecular phylogenetic data in combination with fossil calibrations to estimate the minimum duration of Cape occupation by 14 unrelated putative relicts. Estimates vary widely between lineages (7-101 Myr ago), and when compared with the estimated timing of onset of the modern flora's radiation, it is clear that many, but possibly not all, of these lineages pre-date its establishment. Statistical comparisons of diversities with lineage age show that low species diversity of many of the putative relicts results from a lower rate of diversification than in dated Cape radiations. In other putative relicts, however, we cannot reject the possibility that they diversify at the same underlying rate as the radiations, but have been present in the Cape for insufficient time to accumulate higher diversity. Although the extremes in diversity of currently dated Cape lineages fall outside expectations under a underlying diversification rate, sampling of all Cape lineages would be required to reject this null hypothesis.

A DFT study of propylene polymerization using neutral salicyladiminato nickel(II) and palladium(II) as catalysts

Propylene polymerization using salicyladiminato metal catalalysts has been studied using density functional theory at the B3LYP/LANL2DZ level. In particular, the effects on the reaction mechanisms of changing the metal from Pd(II) to Ni(II) have been investigated. While the reaction mechanisms involving the salicyladiminato Ni(II) catalyst have been found to be similar to those established previously for the salicyladiminato Pd(II) catalyst, the nickel catalyst was found to differentiate the trans-O intermediate from the trans-.N intermediate with an energy difference of 46.63 U mol(-1) significantly more than the palladium catalyst for which the energy difference was calculated as 35.82 kJ mol(-1). The energy difference between the trans-O configuration and the trans-N configuration is decreased significantly when combining a molecule of propylene with the catalyst. For the Ni catalyst, the trans-O isomer is more stable than the trans-N isomer to a greater extent than for Pd, so that the insertion of propylene from 20 is relatively less favoured for Ni than for Pd. It is predicted that the mechanism of isomerization from 20 to 2N through a rotational transition state TS2O2N is more appropriate for the Ni catalyst system. The palladium system shows a larger preference for pi-coordination than its nickel counterpart, although the latter possesses a lower reaction barrier. It was found that the occupation of the trans-O position in the asymmetric salicyladiminato catalyst is also more favored by the alkene as it is by the alkyl so that insertion of the alkene may always start from a particular configuration so that specific products are obtained. (c) 2005 Elsevier B.V. All rights reserved.

Life histories of music service histories, the past in inductees' present

This article discusses inductee music service teachers (to 25 years of age). It explores how their lives, as perceived, shape current identities in teaching and result in several career problems. Respondents were drawn from a comprehensive life history study of 28 Local Education Authority employees. Of this larger cohort, four were age 25 years and below, and the remaining 24 teachers made retrospective comments. Data were collected and analysed between October 2002 and March 2004. Principal findings suggest that schooling failed to address these educators' needs as musical learners; key childhood experiences were external of schools. This often resulted in an idealistic trajectory, in teenage years, towards an occupation as a performer. An occupation in music education was entirely disregarded. Consequently, inductees now consider training experiences an inappropriate platform for their professional lives. Managing group teaching and children's behaviour engenders considerable anxiety. Music service work is also deemed a transient state of affairs. There are implications for training, retention and professional development.

The composition of category conjunctions

In three experiments, the authors investigated the impression-formation process resulting from the perception of familiar or unfamiliar social category combinations. In Experiment 1, participants were asked to generate attributes associated with either a familiar or unfamiliar social category conjunction. Compared to familiar combinations, the authors found that when the conjunction was unfamiliar, participants formed their impression less from the individual constituent categories and relatively more from novel emergent attributes. In Experiment 2 the authors replicated this effect using alternative experimental materials. In Experiment 3, the effect generalized to additional (orthogonally combined) gender and occupation categories. The implications of these findings for understanding the processes involved in the conjunction of social categories, and the formation of new stereotypes, are discussed.

Hydrogen bond-induced pair formation of glycine on the chiral Cu{531} surface

Enantio-specific interactions on intrinsically chiral or chirally modified surfaces can be identified experimentally via comparison of the adsorption geometries of similar nonchiral and chiral molecules. Information about the effects of substrate-related and in interactions on the adsorption geometry of glycine, the only natural nonchiral amino acid, is therefore important for identifying enantio-specific interactions of larger chiral amino acids. We have studied the long- and short-range adsorption geometry and bonding properties of glycine on the intrinsically chiral Cu{531} surface with low-energy electron diffraction, near-edge X-ray absorption One structure spectroscopy, X-ray photoelectron spectroscopy, and temperature-programmed desorption. For coverages between 0.15 and 0.33 ML (saturated chemisorbed layer) and temperatures between 300 and 430 K, glycine molecules adsorb in two different azimuthal orientations, which are associated with adsorption sites on the {110} and {311} microfacets of Cu{531}. Both types of adsorption sites allow a triangular footprint with surface bonds through the two oxygen atoms and the nitrogen atom. The occupation of the two adsorption sites is equal for all coverages, which can be explained by pair formation due to similar site-specific adsorption energies and the possibility of forming hydrogen bonds between molecules on adjacent {110} and {311} sites. This is not the ease for alanine and points toward higher site specificity in the case of alanine, which is eventually responsible for the enantiomeric differences observed for the alanine system.