Final report to the Higher Education Academy. managing connections: using e-learning tracking information to improve retention rates in higher education

The Final Report provides an outline of the research design, the findings and the recommendations which arose from the ‘Managing Connections: using e-learning tracking information to improve retention rates in higher education’ project, which was funded by the Higher Education Academy and Middlesex University between 2007 and 2008

An exploration of perceptions of learning and e-learning held by students who withdraw and those who persist with UK higher education

This paper discusses the relationships that first-year students have with learning and with technology. Due to the lack of previous work linking e-learning with student retention, differences between ‘withdrawers’ and ‘persisters’ were explored. Data were collected using interviews and questionnaires and analysed using thematic analysis. Evidence of a deficit approach to e-learning appears to manifest itself in both groups and technologies that promote social interaction were primarily reserved for personal use rather than within an institutional context. Recommendations from this research include the need to learn how technologies promoting social interaction are used and incorporate lessons learnt into the design of e-learning experiences

Effects of camel grazing on the ecology of small perennial plants in the Dubai (UAE) inland desert

Camel grazing is recognized as a primary cause of ecological degradation in the UAE. A study of perennial plant species \u3c1 m in height was conducted along a fence separating continuously camel grazed land from land in which camels had been replaced by oryx and gazelle species for 5 years (Al Maha). Vegetation regeneration in Al Maha in the absence of camels was considerable on all substrates (gravel, stable sand, and semi-stable sand) but was greatest on the gravel substratum, indicating that ecology in this habitat is most at risk. Observed regeneration was primarily through vegetative reproduction and growth of existing plants, showing that existing species can tolerate heavy grazing. Therefore, an equilibrium grazing model of continuous and reversible vegetation dynamics is most suitable for management of this ecological zone. Species richness was greater in Al Maha due to the greater number of plants, but biodiversity was unaffected. There was some evidence of localized dune stabilization within Al Maha due to increased vegetative cover. Further recovery of vegetation within Al Maha is discussed. This study highlights the need for reduced grazing pressure throughout the Dubai inland desert, and in particular on gravel substrata. © 2006 Elsevier Ltd. All rights reserved

Effects of camel versus oryx and gazelle grazing on the plant ecology of the Dubai Desert Conservation Reserve

Grazing of the Dubai inland desert has changed substantially over the last century, and particularly over the last three decades. Populations of oryx, ostriches and gazelles have been replaced by an increased camel herd, which is at least 2.5 times historical levels. Camel grazing patterns differ to smaller herbivores, affecting plant species composition. Camels are given supplementary feed, so their population is not limited by seasonal availability of vegetation. Desert plants face longer periods of heavy grazing from a larger camel population, and shorter periods for recovery. Plant chemical defenses may also be less effective from the different grazing regime. Although widely considered to be overgrazed, there is little information in the UAE on appropriate stocking levels for purposes of ecological sustainability or for maximizing pastoral production. The effect of grazing on vegetation was studied within the recently formed Dubai Desert Conservation Reserve (DDCR). Camel farms on the DDCR release camels during the day, allowing them to graze natural vegetation within the Reserve. It also contains an inner enclosure of five years in which camels were replaced by oryx and gazelles, separated by a 20 km fence. Fence line studies were made of (1) small (\u3c1m high) perennial plants, (2) seedling emergence during the winter of 2004/5, and (3) size and distribution of large shrubs (\u3c1m high). In addition, telephone surveys were conducted on DDCR farmers, and spatial distribution of trees was recorded. Heavy grazing in the DDCR has reduced the cover of small perennial plant species, reducing their capacity for annual forage production. The extent of overgrazing on gravel substrata was severe, but it was also significant on sand substrata. There was some evidence of localized dune stabilization in the camel exclosure, due to increased vegetation. Germination density of perennial species was greater in the camel exclosure, probably caused by higher seed production of the larger plants. Germination density of annual plant species was not affected by grazing, but was much greater in closer proximity to established small shrubs. No germination was observed to be associated with feces of camels, oryx, gazelle or dhub lizards (Uromastyx aegyptiaca). Plants reached reproductive maturity at a height of 10 cm or less. Large shrubs were differentially impacted by grazing systems. Calligonum comosum was devastated by camel grazing. Leptadenia pyrotechnica and Lycium schawii were substantially reduced in size, though their long term impact is not yet known. Two species benefited from heavy grazing; the large shrub Calotropis procera and the sedge Cyperus conglomeratus. Among trees, the regeneration of Prosopis cineraria appears to have been severely reduced by herbivory at the small shrub stage, but no evidence of effects on Acacia tortilis was recorded. Observed vegetation differences were primarily due to a greater level of grazing in the DDCR than the exclosure, but the ecological impact of camel grazing differs to that of oryx and gazelles. Rapid recovery within the camel exclosure indicates that plant species are well adapted to periods of heavy grazing, and ecological degradation in the DDCR is reversible. Nevertheless, complete recovery of plant species composition may take decades after a reduction of stocking rate. Recovery would benefit native wildlife, and also farmers by reducing their reliance of supplementary feed. Several options for reducing the impact of camel grazing are considered. © 2006 Taylor & Francis Group, London

Effects of camel grazing on density and species diversity of seedling emergence in the Dubai (UAE) inland desert

Germination in the arid rangelands of the UAE occurs as an \u27event\u27 following a mid-winter to spring rainfall. A fence line study of germination events was conducted in 2005 and 2006 to identify the response to differential grazing regimes. Fifty-six 1 m2 seedling plots were destructively sampled each season. Heavy grazing reduced species richness and diversity without significantly reducing seedling density. Both annual and perennial species were impacted, though the reduction in richness of annual species was less pronounced than the natural variation among locations. Direct grazing of seedlings is limited to a few weeks, due to the short annual plant life span. Reduction of perennial seedling density and species richness was likely caused by the reduced size of adult plants under grazing. Recruitment of perennial species could be affected by heavy grazing, leading to loss of habitat, though under moderate grazing levels this could easily be compensated by greater survival. © 2007 Elsevier Ltd. All rights reserved

1.55 μm direct bandgap electroluminescence from strained n-Ge quantum wells grown on Si substrates

Electroluminescence from strained n-Ge quantum well light emitting diodes grown on a silicon substrate are demonstrated at room temperature. Electroluminescence characterisation demonstrates two peaks around 1.55 μm and 1.8 μm, which correspond to recombination between the direct and indirect transitions, respectively. The emission wavelength can be tuned by around 4% through changing the current density through the device. The devices have potential applications in the fields of optical interconnects, gas sensing, and healthcare

The development of magmatism along the Cameroon Volcanic Line: evidence from seismicity and seismic anisotropy

The Cameroon Volcanic Line (CVL) straddles the continent-ocean boundary in West Africa but exhibits no clear age progression. This renders it difficult to explain by traditional plume/plate motion hypotheses; thus, there remains no consensus on the processes responsible for its development. To understand better the nature of asthenospheric flow beneath the CVL, and the effects of hotspot tectonism on the overlying lithosphere, we analyze mantle seismic anisotropy and seismicity. Cameroon is relatively aseismic compared to hotspots elsewhere, with little evidence for magmatism-related crustal deformation away from Mount Cameroon, which last erupted in 2000. Low crustal Vp/Vs ratios (?1.74) and a lack of evidence for seismically anisotropic aligned melt within the lithosphere both point toward a poorly developed magmatic plumbing system beneath the CVL. Null SKS splitting observations dominate the western continental portion of the CVL; elsewhere, anisotropic fast polarization directions parallel the strike of the Precambrian Central African Shear Zone (CASZ). The nulls may imply that the convecting upper mantle beneath the CVL is isotropic, or characterized by a vertically oriented olivine lattice preferred orientation fabric, perhaps due to a mantle plume or the upward limb of a small-scale convection cell. Precambrian CASZ fossil lithospheric fabrics along the CVL may have been thermomechanically eroded during Gondwana breakup ?130?Ma, with an isotropic lower lithosphere subsequently reforming due to cooling of the slow-moving African plate. Small-scale lithospheric delamination during the 30?Ma recent development of the line may also have contributed to the erosion of the CASZ lithospheric fossil anisotropy, at the same time as generating the low-volume alkaline basaltic volcanism along the CV

Low loss Ge-on-Si waveguides operating in the 8–14 µm atmospheric transmission window

Germanium-on-silicon waveguides were modeled, fabricated and characterized at wavelengths ranging from 7.5 to 11 µm. Measured waveguide losses are below 5 dB/cm for both TE and TM polarization and reach values of ∼ 1 dB/cm for ≥ 10 µm wavelengths for the TE polarization. This work demonstrates experimentally for the first time that Ge-on-Si is a viable waveguide platform for sensing in the molecular fingerprint spectral region. Detailed modeling and analysis is presented to identify the various loss contributions, showing that with practical techniques losses below 1 dB/cm could be achieved across the full measurement range

Ohmic contacts to n-type germanium with low specific contact resistivity

A low temperature nickel process has been developed that produces Ohmic contacts to n-type germanium with specific contact resistivities down to (2.3 ± 1.8) x10<sup>-7</sup> Ω-cm<sup>2</sup> for anneal temperatures of 340 degC. The low contact resistivity is attributed to the low resistivity NiGe phase which was identified using electron diffraction in a transmission electron microscope. Electrical results indicate that the linear Ohmic behaviour of the contact is attributed to quantum mechanical tunnelling through the Schottky barrier formed between the NiGe alloy and the heavily doped n-Ge.<p></p&gt