987 research outputs found
Anthrakologische Untersuchungen zur Vegetationsgeschichte des Kaokolandes, Nordwest-Namibia
Mit dem Ziel, zur AufklĂ€rung der Vegetationsgeschichte des nordwestlichen Namibia beizutragen, wurden holzkohleanalytische Untersuchungen an Material aus archĂ€ologischen Fundstellen im Kaokoland durchgefĂŒhrt. Grundvoraussetzung hierfĂŒr war der Aufbau einer Vergleichssammlung rezenter namibischer Hölzer und die Erstellung eines holzanatomischen Merkmalskataloges mit dichotomem SchlĂŒssel. Das Arbeitsgebiet wird von den pastoralnomadischen Himba und Herero besiedelt und ist durch einen steilen Klimagradienten gekennzeichnet. Dieser ist der Hauptfaktor fĂŒr die heutige Anordnung der Vegetationseinheiten im Kaokoland. Vor den im Rahmen dieser Arbeit durchgefĂŒhrten Untersuchungen war wenig ĂŒber die holozĂ€ne und spĂ€tpleistozĂ€ne Vegetationsgeschichte Namibias bekannt. Aufgrund des ariden Klimas der Region gibt es kaum pollenerhaltende Sedimente. Marine Pollenanalysen haben zur Kenntnis der Umweltgeschichte des sĂŒdwestlichen Teils des afrikanischen Kontinents beigetragen. Sie können jedoch nicht die lokale bis regionale Vegetationsgeschichte Nordwest-Namibias aufklĂ€ren. Die Erhaltung von Holzkohlen in holozĂ€nen und teilweise in spĂ€tpleistozĂ€nen Horizonten in Abris im Kaokoland ist gut. Vorausgesetzt, dass die Ablagerungen ungestört sind, ist die Holzkohlenanalyse ein angemessenes Mittel, zur AufklĂ€rung der Vegetations- und Klimageschichte der Region. Holzkohlenanalysen von Fundstellen im östlichen Kaokoland belegen die Abwesenheit einer Mopane-Savanne und die Dominanz der Gattung Acacia in der Gehölzvegetation des ausgehenden PleistozĂ€ns. Sowohl die Temperaturen als auch die Niederschlagsbedingungen lagen mit hoher Wahrscheinlichkeit unter den heutigen. Anthrakologische Ergebnisse zum FrĂŒhholozĂ€n stammen vom Fundplatz Omungunda im östlichen, niederschlagsreichen Teil des Arbeitsgebietes. Es lĂ€sst sich bereits auf die Anwesenheit einer Mopane-Savanne wĂ€hrend dieses Zeitraumes schlieĂen, aber die Abwesenheit typischer Taxa der heutigen "Colophospermum mopane-Spirostachys africana-Baumsavanne" weist auf deutlich trockenere klimatische Bedingungen hin. Mittel- und spĂ€tholozĂ€ne Holzkohleablagerungen zeigen nur geringe Abweichungen der Artenzusammensetzung und ihrer relativen Anteile. Beides weist auf relativ stabile Umweltbedingungen wĂ€hrend dieser Periode hin. FĂŒr die einzelnen Fundstellen können typische Artengruppen ausgegrenzt werden, die mit den heutigen umgebenden Vegetationseinheiten korrespondieren. Ihr stetiges Auftreten in den jeweiligen Fundstellen ist ein Hinweis, dass die ökologischen Bedingungen sich kaum verĂ€ndert haben. Der Nachweis des Colophospermum mopane Typs in den Holzkohlen der Fundstelle N 2000/1 im ariden Westen weist auf geringfĂŒgig feuchtere Bedingungen um 2000 BP hin. Eine weitere Feuchteschwankung lĂ€sst sich aus dem Fund von Terminalia prunioides Holzkohle in einer Fundstelle im nordwestlichen Kaokoland schlieĂen. In ErgĂ€nzung zu den Holzkohleanalysen wurden Interviews zur aktuellen Brennholznutzung durchgefĂŒhrt, um Informationen ĂŒber den Einfluss der selektiven Brennholzwahl zu erhalten. Die Ergebnisse zeigen, dass die Brennholzwahl tatsĂ€chlich selektiv ist, sich aber mit den Vegetationseinheiten entlang des Klimagradienten Ă€ndert. Daher kann in diesem Fall der Einfluss auf die archĂ€obotanischen Ergebnisse als begrenzt angesehen werden
Espace naturel, techniques agraires et végétation ségétale en pays Kassena
Les Kassena, une ethnie sĂ©dentaire appartenant au groupe linguistique des Gurunsi, habitent dans une rĂ©gion au sud du Burkina Faso et au nord du Ghana. Leur Ă©conomie est basĂ©e sur lâautosubsistance Ă partir de la culture du mil et lâĂ©levage du bĂ©tail. Avec une saison des pluies de six mois et une pluviomĂ©trie de plus de 900 mm, la rĂ©gion offre des conditions favorables Ă la culture du mil. Cette rĂ©gion est caractĂ©risĂ©e par une forte inĂ©galitĂ© en ce qui concerne la dispersion de lâhabitat. Certaines rĂ©gions, comme les alentours de la montagne de TiĂ©bĂ©lĂ© qui, selon les rĂ©cits de la tradition orale, est lâancien centre des Kassena de lâest, connaissent une importante population allant jusquâĂ 100 habitants par km/carrĂ©. Dâautres rĂ©gions, notamment la vallĂ©e du Nazinon, Ă©taient plus ou moins inhabitĂ©es jusquâĂ ces derniĂšres annĂ©es. Ceci est probablement dĂ» aux maladies endĂ©miques comme lâonchocercose. Pour les rĂ©gions les plus peuplĂ©es, nous avons cherchĂ© Ă connaĂźtre les techniques spĂ©cifiques qui ont permis Ă la population de sâinstaller et de sâalimenter. Les Kassena maĂźtrisent un systĂšme de culture permanente sur des champs terrassĂ©s exigeant beaucoup dâentretien. Ces champs sont soumis Ă un contrĂŽle social et religieux. De plus, les Kassena cultivent des champs de brousse qui se trouvent souvent dans la plaine et Ă grande distance des villages. Ces champs de brousse sont cultivĂ©s dâune façon plus extensive. Le prĂ©sent exposĂ© dĂ©crit les techniques de lâagriculture en respect des conditions de lâenvironnement. Lâobjectif est de mieux comprendre les stratĂ©gies Ă©conomiques et culturelles des cultivateurs de cette rĂ©gion
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Fuel selection during long-term ancient iron production in Sudan
The Royal City of Meroe, a capital of the ancient Kushite kingdom in modern Sudan, is renowned for its extensive remains of ancient iron production. The exploitation of wood to fuel Meroeâs metallurgical past has long been linked to environmental degradation. However, palaeoenvironmental studies involving archaeobotanical methods such as charcoal analysis, which might confirm or disprove the hypothesis of large-scale deforestation, have so far been missing for the area. Our investigations offer the first comprehensive anthracological data for the iron-smelting contexts at Meroe and its surroundings covering more than 1000 years. They provide unequivocal evidence for extreme selectivity for a single species, the Nile acacia Acacia nilotica (Syn. Vachellia nilotica), throughout the course of the currently known metallurgical history of the Meroe region. The charcoal data neither point to fuel shortage nor to environmental degradation at any point in time during the entire production period. Non-metallurgical contexts show that a wider array of taxa was used for fuel with low values of Acacia nilotica type charcoal. We thus conclude that Acacia nilotica wood was preferably used and mainly spared for the technical application of iron smelting. The probable source areas for Nile acacia wood and possible woody resource management strategies to maintain the fuel supply are discussed.The archaeological research discussed in this paper was funded by Qatar Sudan Archaeology Project [grant number 037] and UCL Qatar. The British Institute in Eastern Africa (BIEA) funded the anthracological investigations
First archaeobotanical plant macro-remain analysis from the Middle Bronze Age wetland settlement of Viverone (Viverone âEmissarioâ Project: campaign Viv16)
YesThe first archaeobotanical studies of the Middle Bronze Age lakeshore settlement demonstrate the enormous potential of this
site for appropriate analyses. On the basis of the well-preserved layers a multitude of plant remains and wide diversity of species are present at this site. Evidence of emmer, spelt, tetraploid naked wheat, hulled barley, peas and broad beans conforms to the basic cultural crop spectrum of the Middle Bronze Age. The wild plants originate from various locations in the direct vicinity and allow an insight into the landscape at that time. Numerous wild plants were intentionally used by the settlers. Fruits gathered include cornelian cherries, hazelnuts, crab apples and a diversity of berries.
Furthermore, archaeobotanical analyses support observations already made on site that within the settlement there are at least two functionally different areas. While in section 50/51 the layers contain the remains of daily food preparation, section 7 indicates a link to animal fodder.National Geographi
Effect of metoprolol on myocardial function and energetics in patients with nonischemic dilated cardiomyopathy: A randomized, double-blind, placebo-controlled study
AbstractObjectives. This study examined the of metoprolol on left ventricular performance, efficiency, neurohormonal activation and myocardial respiratory quotient in patients with dilated cardiomyopathy.Background.The mechanism by which beta-adrenergie blockade improves ejection fraction in patients with dilated cardiomyopathy remains an enigma. Thus, we undertook an extensive hemodynamic evaluation of this mechanism. In addition, because animal models have shown that catecholamine exposure may increase relative fatty acid utilization, we hypothesized that antagonism of sympathetic stimulation may result in increased carbohydrate utilization.Methods. This was a randomized, double-blind, prospective trial in which 24 men with nonischemic dilated cardiomyopathy underwent cardiac catheterization before and after 3 months of therapy with metoprolol (n = 15) or placebo (n = 9) in addition to standard therapy. Pressure-volume relations were examined using a micromanometer catheter and digital ventriculography.Results. At baseline, the placebo-treated patients had somewhat more advanced left ventricular dysfunction. Ejection fraction and left ventricular performance improved only in the metoprolol-treated patients. Stroke and minute work increased without an increase in myocardial oxgen consumption, suggesting increased myocardial efficiency. Further increases in ejection fraction were seen between 3 and 6 months in the metoprolol group. The placebo group had a significant increase in ejection fraction only after crossover to metoprolol. A significant relation the change in coronary sinus norepinephrine and myocardial respiratory quotient was seen, suggesting a possible effect of adrenergic deactivation on substrate utilization.Conclusions. These data demonstrate that in patients with cardiomyopthy, metoprolol treatment improves myocardial performance and energetics, and favorably alters substrate utilization. Beta-adrenergic blocking agents, such as metoprolol, are hemodynamically and energetically beneficial in the treatment of myocardial failure
Isotopic and microbotanical insights into Iron Age agricultural reliance in the Central African rainforest
The emergence of agriculture in Central Africa has previously been associated with the migration of Bantu-speaking populations during an anthropogenic or climate-driven âopeningâ of the rainforest. However, such models are based on assumptions of environmental requirements of key crops (e.g. Pennisetum glaucum) and direct insights into human dietary reliance remain absent. Here, we utilise stable isotope analysis (ÎŽ13C, ÎŽ15N, ÎŽ18O) of human and animal remains and charred food remains, as well as plant microparticles from dental calculus, to assess the importance of incoming crops in the Congo Basin. Our data, spanning the early Iron Age to recent history, reveals variation in the adoption of cereals, with a persistent focus on forest and freshwater resources in some areas. These data provide new dietary evidence and document the longevity of mosaic subsistence strategies in the region
Newsletter Networks in the Feminist History and Archives Movement
This article examines how networks have been critical to the construction of feminist histories. The author examines the publication Matrices: A Lesbian/Feminist Research Newsletter (1977â1996), to argue that a feminist network mode can be traced through the examination of small-scale print newsletters that draw on the language and function of networks. Publications such as Matrices emerge into wide production and circulation in the 1970s alongside feminist community archives, and newsletters and archives work together as interconnected social movement technologies. Newsletters enabled activist-researchers writing feminist histories to share difficult-to-access information, resources, and primary sources via photocopying and other modes of print reproduction. Looking from the present, the author examines how network thinking has been a feature of feminist activism and knowledge production since before the Internet, suggesting that publications such as Matrices are part of a longer history of networked communications media in feminist contexts
Differential cross section measurements for the production of a W boson in association with jets in protonâproton collisions at âs = 7 TeV
Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript â1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio
Search for stop and higgsino production using diphoton Higgs boson decays
Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass
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