260 research outputs found
At the Post Office
This resource contains a dialogue which takes place at the post office. It involves a woman customer who wishes to send a registered letter.
The dialogue is pitched at level 3 (B1/2 accroding to the CEFR) and some exercises follow
Procrastination - a Tigrinyan poem
This Tigrinya poem is based on an English poem, whose author is not known
Tigrinya Idioms
Idioms such as the four items, which are underlined, are so linked with the tradition, it is essential for those born in the Diaspora to learn and appreciate their denotative and conotative meanings
Miocene faunal remains from the Burji-Soyama area, Amaro Horst, southern sector of the main Ethiopian Rift
The Palaeoanthropological Inventory of Ethiopia is dedicated to the discovery and documentation of palaeoanthropologically significant study areas in the Main Ethiopian Rift and Afar Depression. Fieldwork in the area at the southern end of the Amaro Horst during the 1989 field season was focused on a fossiliferous sedimentary succession with intercalated volcanic horizons. Potassium-argon dating sets a minimum age of 11.1 my for sediments bearing vertebrate remains. The partial skeleton of a fossil proboscidean recovered at Burji is described, illustrated and assessed comparatively. The remains are those of a primitive species of choerolophodont mastodon. Biochronological considerations place this specimen in the time range of 15-17 my. The presence of fossiliferous sediments in the Burji area suggest that a rift-related basin had developed in this part of Ethiopia by Middle or Early Miocene times.National Geographic Society 4134-89; National Science Foundation Anthropology Program: BSN 88-19735; Centre for Research and Conservation of the Cultural Heritage,
Ethiopian Ministry of Culture and Sports Affair
Dynamic landscapes and human dispersal patterns : tectonics, coastlines, and the reconstruction of human habitats
Studies of the impact of physical environment on human evolution usually focus on climate as the main external forcing agent of evolutionary and cultural change. In this paper we focus on changes in the physical character of the landscape driven by geophysical processes as an equally potent factor. Most of the landscapes where finds of early human fossils and artefacts are concentrated are ones that have been subjected to high levels of geological instability, either because of especially active tectonic processes associated with faulting and volcanic activity or because of proximity to coastlines subject to dramatic changes of geographical position and physical character by changes of relative sea level. These processes can have both beneficial effects, creating ecologically attractive conditions for human settlement, and deleterious or disruptive ones, creating barriers to movement, disruption of ecological conditions, or hazards to survival. Both positive and negative factors can have powerful selective effects on human behaviour and patterns of settlement and dispersal. We consider both these aspects of the interaction, develop a framework for the reconstruction and comparison of landscapes and landscape change at a variety of scales, and illustrate this with selected examples drawn from Africa and Arabia
Se Isotopes as Groundwater Redox Indicators:Detecting Natural Attenuation of Se at an in Situ Recovery U Mine
One
of the major ecological concerns associated with the in situ
recovery (ISR) of uranium (U) is the environmental release of soluble,
toxic selenium (Se) oxyanions generated by mining. Post-mining natural
attenuation by the residual reductants in the ore body and reduced
down-gradient sediments should mitigate the risk of Se contamination
in groundwater. In this work, we investigate the Se concentrations
and Se isotope systematics of groundwater and of U ore bearing sediments
from an ISR site at Rosita, TX, USA. Our results show that selenate
(SeÂ(VI)) is the dominant Se species in Rosita groundwater, and while
several up-gradient wells have elevated SeÂ(VI), the majority of the
ore zone and down-gradient wells have little or no Se oxyanions. In
addition, the δ<sup>82</sup>Se<sub>VI</sub> of Rosita groundwater
is generally elevated relative to the U ore up to +6.14‰, with
the most enriched values observed in the ore-zone wells. Increasing
δ<sup>82</sup>Se with decreasing SeÂ(VI) conforms to a Rayleigh
type distillation model with an ε of −2.25‰ ±
0.61‰, suggesting natural SeÂ(VI) reduction occurring along
the hydraulic gradient at the Rosita ISR site. Furthermore, our results
show that Se isotopes are excellent sensors for detecting and monitoring
post-mining natural attenuation of Se oxyanions at ISR sites
P20-12. Heterogeneity of Gag mutational pathways in primary HIV-1 subtype C infection
Poster presentatio
A pulse of mid-Pleistocene rift volcanism in Ethiopia at the dawn of modern humans
The Ethiopian Rift Valley hosts the longest record of human co-existence with volcanoes on Earth, however, current understanding of the magnitude and timing of large explosive eruptions in this region is poor. Detailed records of volcanism are essential for interpreting the palaeoenvironments occupied by our hominin ancestors; and also for evaluating the volcanic hazards posed to the 10 million people currently living within this active rift zone. Here we use new geochronological evidence to suggest that a 200 km-long segment of rift experienced a major pulse of explosive volcanic activity between 320 and 170 ka. During this period, at least four distinct volcanic centres underwent large-volume (>10 km3) caldera-forming eruptions, and eruptive fluxes were elevated five times above the average eruption rate for the past 700 ka. We propose that such pulses of episodic silicic volcanism would have drastically remodelled landscapes and ecosystems occupied by early hominin populations
- …