Population expansion in the North African Late Pleistocene signalled by mitochondrial DNA haplogroup U6

Background <br/> The archaeology of North Africa remains enigmatic, with questions of population continuity versus discontinuity taking centre-stage. Debates have focused on population transitions between the bearers of the Middle Palaeolithic Aterian industry and the later Upper Palaeolithic populations of the Maghreb, as well as between the late Pleistocene and Holocene. <br/> Results Improved resolution of the mitochondrial DNA (mtDNA) haplogroup U6 phylogeny, by the screening of 39 new complete sequences, has enabled us to infer a signal of moderate population expansion using Bayesian coalescent methods. To ascertain the time for this expansion, we applied both a mutation rate accounting for purifying selection and one with an internal calibration based on four approximate archaeological dates: the settlement of the Canary Islands, the settlement of Sardinia and its internal population re-expansion, and the split between haplogroups U5 and U6 around the time of the first modern human settlement of the Near East. <br/> Conclusions <br/> A Bayesian skyline plot placed the main expansion in the time frame of the Late Pleistocene, around 20 ka, and spatial smoothing techniques suggested that the most probable geographic region for this demographic event was to the west of North Africa. A comparison with U6's European sister clade, U5, revealed a stronger population expansion at around this time in Europe. Also in contrast with U5, a weak signal of a recent population expansion in the last 5,000 years was observed in North Africa, pointing to a moderate impact of the late Neolithic on the local population size of the southern Mediterranean coast

Guidelines for the Integrated Management of Mountain Ecosystems

The United Nations Conference of Environment and Development in Rio de Janeiro (1992), the Earth Summit, appropriately recognized the mountains as one of the most threatened ecosystems on the planet. Recent research has shown that this threat may increase significantly in the future as a result of the greenhouse effect. At Rio the nations of the world agreed to a mountain agenda for the 21st century. But although the principles are clear enough there are very few practical guides on how actually to implement Agenda 21 especially at the grass roots. This small publication is a first attempt to spell out the first steps in doing something about the crisis in the mountains. What follows is derived from a joint project in the 1980s involving UNEP, the USSR State Committee for Environmental Protection, Centre for International Projects, the Bulgarian Ministry of Agriculture and Food Industry, Academy of Agriculture, the Poushkarov Institute of Soil Science and Agroecology, and the Georgian Agricultural Academy of Sciences. The objectives of the project were to create an international network of experts, both distinguished scientists and representatives of the leading international organizations who would direct field experiments and consider alternative methods for the complex integrated management of mountain ecosystems. The experimental plots were in the Caucasus, the Rhodopes, and Balkan mountains, including a range of mountain situations -- mediterranean, subtropical, high mountains, etc. To these sites were brought students mainly from developing countries, to learn at first hand the practical details of environmental protection in the mountains. From these courses guidelines were produced which form the basis for this publication. There were many other by-products of great use -- films, advisory missions to the Himalayas and Africa, classifications of soils and productivity, technical reports on a range of topics including landslides, mechanization, and agroecology. The project was evaluated as a success story and most appreciated by the students who greatly enjoyed the summer journeys into the idyllic Georgian and Bulgarian mountains. Whatever happens to the project in these more wintry times, the networks forged in those remote valleys will endure. Indeed the project brought together from such regions as the Andes experts and students who never met at home but who now cooperate actively

Neural Networks for Self-tuning Control Systems

In this paper, we presented a self-tuning control algorithm based on a three layers perceptron type neural network. The proposed algorithm is advantageous in the sense that practically a previous training of the net is not required and some changes in the set-point are generally enough to adjust the learning coefficient. Optionally, it is possible to introduce a self-tuning mechanism of the learning coefficient although by the moment it is not possible to give final conclusions about this possibility. The proposed algorithm has the special feature that the regulation error instead of the net output error is retropropagated for the weighting coefficients modifications.

Histološke i biokemijske promjene u jetri i bubrezima štakora izazvane torijevim nitratom

The histopathological and biochemical alterations in rat\u27s liver and kidney induced by daily intraperitoneal administration of thorium nitrate were studied. The activity of alkaline phosphatase and adenosine triphosphatase was found to be inhibited at various intervals and the pathomorphological changes were found to be related to the duration of treatment. The results indicate that the effect of thorium is cumulative and that the biochemical alterations occur prior to histological changes.Toksikološka svojstva torija slabo su istražena, iako torij postaje sve važniji elemenat u industriji. Njegova se upotreba širi, pa se upotrebljava i u medicinskoj dijagnostici (torijev dioksid - thorotrast). U ovom su radu istraživani učinci torijevih soli na bubrege i jetru štakora kojima je torijev nitrat injiciran intraperitonealno u dozi od 10 mg/kg svakog dana kroz 120 dana. Kontrolnim je životinjama injicirana fiziološka otopina na jednak način. U prvih 60 dana pokusa samo je nekoliko štakora uginulo, a nakon toga vremena smrtnost se povećala. Tek nakon 30 dana uočene su histološke promjene jetre u obliku kongestije vena i sinusoida i taj je nalaz postajao sve izrazitiji tijekom vremena. U kasnijoj su fazi nađena degenerativna i nekrotična žarišta. Slične su promjene nađene i u bubrežnom parenhimu. Ovim je promjenama prethodilo smanjenje aktivnosti alkalne fosfataze i adenozin trifosfataze u jetri i u još većoj mjeri u bubregu

Evaluation of Dynamic Cell Processes and Behavior Using Video Bioinformatics Tools

Just as body language can reveal a person’s state of well-being, dynamic changes in cell behavior and morphology can be used to monitor processes in cultured cells. This chapter discusses how CL-Quant software, a commercially available video bioinformatics tool, can be used to extract quantitative data on: (1) growth/proliferation, (2) cell and colony migration, (3) reactive oxygen species (ROS) production, and (4) neural differentiation. Protocols created using CL-Quant were used to analyze both single cells and colonies. Time-lapse experiments in which different cell types were subjected to various chemical exposures were done using Nikon BioStations. Proliferation rate was measured in human embryonic stem cell colonies by quantifying colony area (pixels) and in single cells by measuring confluency (pixels). Colony and single cell migration were studied by measuring total displacement (distance between the starting and ending points) and total distance traveled by the colonies/cells. To quantify ROS production, cells were pre-loaded with MitoSOX Red™, a mitochondrial ROS (superoxide) indicator, treated with various chemicals, then total intensity of the red fluorescence was measured in each frame. Lastly, neural stem cells were incubated in differentiation medium for 12 days, and time lapse images were collected daily. Differentiation of neural stem cells was quantified using a protocol that detects young neurons. CLQuant software can be used to evaluate biological processes in living cells, and the protocols developed in this project can be applied to basic research and toxicological studies, or to monitor quality control in culture facilities

Ultraviolet astronomy with small space telescopes

After describing the present situation with astronomy in the ultraviolet (UV), reviewing a few past and proposed future missions, we present options to develop space missions that have been realized for modest costs. In this context, we bring together a few aspects of different missions and projects that, when combined, might result in a low-cost mission for imaging or low resolution spectroscopy in the UV

THE COMPLEX CIRCUMNUCLEAR ENVIRONMENT of the BROAD-LINE RADIO GALAXY 3C 390.3 REVEALED by CHANDRA HETG

We present the first high spectral resolution X-ray observation of the broad-line radio galaxy 3C 390.3 obtained with the high-energy transmission grating spectrometer on board the Chandra X-ray Observatory. The spectrum shows complex emission and absorption features in both the soft X-rays and Fe K band. We detect emission and absorption lines in the energy range E = 700–1000 eV associated with ionized Fe L transitions (Fe XVII–XX). An emission line at the energy of E sime 6.4 keV consistent with the Fe Kα is also observed. Our best-fit model requires at least three different components: (i) a hot emission component likely associated with the hot interstellar medium in this elliptical galaxy with temperature kT = 0.5 ± 0.1 keV; (ii) a warm absorber with ionization parameter logξ = 2.3 ± 0.5 erg s−1 cm, column density logN H = 20.7 ± 0.1 cm−2, and outflow velocity v out < 150 km s−1; and (iii) a lowly ionized reflection component in the Fe K band likely associated with the optical broad-line region or the outer accretion disk. These evidences suggest the possibility that we are looking directly down the ionization cone of this active galaxy and that the central X-ray source only photoionizes along the unobscured cone. This is overall consistent with the angle-dependent unified picture of active galactic nuclei