103,450 research outputs found
Adverse birth outcome: a comparative analysis between cesarean section and vaginal delivery at Felegehiwot Referral Hospital, Northwest Ethiopia: a retrospective record review [Corrigendum]
No full textAbebe Eyowas F, Negasi AK, Aynalem GE, Worku AG. Pediatric Health, Medicine and Therapeutics. 2016;7:65–70On page 65 Abel Fekadu Dadi should have been listed as an author. The incorrect author list was:Fantu Abebe Eyowas1Ashebir Kidane Negasi1Gizachew Eyassu Aynalem1Abebaw Gebeyehu Worku2The correct author list should have been:Fantu Abebe Eyowas1Ashebir Kidane Negasi1Gizachew Eyassu Aynalem1Abebaw Gebeyehu Worku2Abel Fekadu Dadi2Read the original articl
Stile deformativo e reticolo idrografico lungo la scarpata del Plateau Somalo al margine meridionale dell'Afar
No full textAmphibian diversity, distribution and conservation in the Ethiopian highlands : morphological, molecular and biogeographic investigation on Leptopelis and Ptychadena (Anura)
No full textLittle is known about the diversity, distribution and population status of Ethiopian amphibians in general, and most of the existing knowledge is based on field data recorded about three decades ago or earlier. There are almost no genetic data available for molecular systematics studies. Species of the Tree Frogs (Leptopelis Günther 1859) and Grassland Frogs (Ptychadena Boulenger 1917) are solely distributed in Africa (mainly sub-Saharan), with 52 and 53 known species, respectively. Six species of Leptopelis and thirteen species of Ptychadena were recorded in Ethiopia. Together these two genera comprise 30% of all known species of amphibians in Ethiopia. Many of these species (five Leptopelis and five Ptychadena) are said to be endemic to the Ethiopian Highlands that are part of the Eastern Afromontane Biodiversity Hotspot. Geographically, the Ethiopian Highlands are bisected by the Rift Valley, and further fragmented by valleys and gorges, and comprise the highest concentration of elevated ground in Africa. Earlier taxonomic studies were mainly based on morphological and ecological studies, making it difficult to identify most species in museum collections or during field work. In addition, limited sampling from the geographic areas of each species made it difficult to make good estimates of the ranges of species, and to prioritize them for conservation.
The main objectives of this study are, using Leptopelis and Ptychadena as model taxa, 1) to explore the diversity and phylogeography of some amphibians in the Ethiopian Highlands and parts of the Rift Valley; 2) to preliminarily explain the geo-climatic events that are associated with the evolutionary history of these taxa; and 3) to re-evaluate the conservation status of species and their habitats by associating phylogenetic, biogeographic and ecological information. We tested hypotheses pertaining to correspondence of traditional morphological taxonomy versus molecular phylogeny, biogeographic distinctness of distribution patterns, evolutionary history of diversification, and evaluation of conservation status of species and populations in the highlands.
The field sampling conducted between 2006 and 2010 from several localities across and within the Ethiopian Rift Valley was substantial, but not enough, to fully assess the phylogeography of the above genera. This assessment, conducted for the first time for Ethiopian Leptopelis and Ptychadena, was done using partial mitochondrial DNA sequences of the 12S and 16S genes. Estimation of phylogenetic relationships and divergence times was made using Maximum Likelihood and Maximum Parsimony methods. Morphological observations were made on fresh collections, holotypes and non-type museum materials. Biogeographic patterns were assessed using geographic distribution data. Geographic and spatial data were combined with new phylogenetic groupings to assess geographic ranges and habitat status of populations and species. We followed a new approach of ‘elevation-based’ extent of occurrence (instead of the simple polygons applied in the IUCN Red List maps) to estimate geographic ranges. Results were compared and evaluated with previous reports and online database.
Despite the wide taxonomic variation between the studied genera (Leptopelis and Ptychaena), we found similarities in some of their major taxonomic problems, as well as evolutionary, biogeographic and conservation aspects. The similarities are in: overlaps in many morphological characters (conservatism) among different species; misleading variation in some physical features within a population/species (homoplasy); monophyly of highland endemic species; cryptic phylo-groups embedded within known clades; relatively low genetic distance between species and recent evolutionary divergence times; habitat status and threats for survival of populations.
In both genera, the reconstructed phylogenetic relationships showed that the highland endemic species form well-supported monophyletic groups: the ‘Ethiopian Highland Leptopelis species group’, and the ‘Ptychadena cooperi species group’. Cryptic diversity of highland endemics was revealed, highlighting the possibility of having six candidate species (at least two Leptopelis and four Ptychadena) awaiting description. Two presumed lowland endemic species of Ptychadena (P. filwoha and P. harenna) were genetically found to be conspecific with other widely distributed (non-endemic) lowland species (P. mascareniensis and P. anchietae, respectively).
Wide overlaps in several morphological features made identification of some closely related species populations difficult. New diagnostic features were identified to characterize some of the most difficult groups (e.g., presence of spicules in males of P. neumanni contrasted with absence in P. erlangeri or P. nana).
As compared with some other African species for which molecular data are available, relatively small evolutionary distances were found among the highland species within each genus, explained by a possibly very recent radiation as estimated in the corresponding divergence times. Diversification of the highland endemics was probably associated with formation of the Ethiopian Highlands by volcanic activities and uplifting, and accompanying climatic changes between 30 and 6 Mya.
We observed congruence of phylogenetic groups with clear patterns of geographic distribution, allowing us to identify distinct biogeographic categories that can potentially serve as units for conservation of Ethiopian amphibians. The Rift Valley and major river gorges appear important horizontal barriers delimiting geographic ranges of most species. There is no considerable vertical (altitudinal) segregation of the highland populations in the two genera.
The highland Leptopelis and Ptychadena comprise more diverse endemic species (16) than known before (10), contributing substantially to the biodiversity value of the Ethiopian Highlands. While range extension is revealed for some species in the current study, there is unfortunately a substantial reduction for others from what has been proposed previously. Land cover data and our field observation of many parts of the country for about two decades indicate that large parts of the suitable highland habitats for most species of Leptopelis and Ptychadena are severely degraded and fragmented by human activities. Lakes are drying, levels of rivers are decreasing, and the wooded and grassland vegetation of the highlands and the Rift Valley is being lost. Our revised assessment of populations showed that nine of the 16 studied species appear to be threatened at different levels. This implies an urgent need for revision of existing conservation status of these taxa to protect them in rapidly changing environments. Further work is needed in the areas of phylogeography, taxonomy, and natural history of populations and species in areas that are not covered in this study
sj-docx-1-his-10.1177_11786329231157467 – Supplemental material for Intravenous Immunoglobulin G (IVIG) Need Assessment Survey Toward Local Manufacturing of IVIG Using a Mini-Pool Plasma Fractionation Technique
No full textSupplemental material, sj-docx-1-his-10.1177_11786329231157467 for Intravenous Immunoglobulin G (IVIG) Need Assessment Survey Toward Local Manufacturing of IVIG Using a Mini-Pool Plasma Fractionation Technique by Bisrat Bekele, Zekarias Masresha, Mekdelawit Alemayehu, Berhanu Seyoum, Liya Wassie and Markos Abebe in Health Services Insights</p
Rates of Late Quaternary deformation along the Wonji fault belt in the Lakes Region, Main Ethiopian Rift.
No full textThe Wonji fault belt (Main Ethiopian Rift): structural and geomorphological constraints and GPS monitoring.
No full textThe Wonji Fault Belt (WFB), Main Ethiopian Rift, forms a network of faults oriented NNE-SSW with a Quaternary direction of extension oriented c. N95° E. Faults are spaced between 0.5 and 2 km, show a fresh steep scarp, recent activity and slip rates of up to 2.0 mm a−1. This high value of deformation along the rift floor with respect to the plate separation rates suggests that most of the active strain could be accommodated by magma-induced faulting within the rift. However, the mountain front morphology associated with a displacement of 300–400 m since the Middle Pleistocene, tilted-blocks, brittle-seismic fault rock fabric and historical earthquakes with M>6 support a tectonic origin of the Asela boundary fault. Therefore, we propose a model that considers the possible coexistence of both magmatic deformation at the rift floor and brittle faulting at the rift margin. We also report the data relative to a GPS network installed in December 2004, along two transects across the WFB, between Asela and the Ziway Lake
Style of faulting and drainage pattern along the Somalian plateau escarpment at the southern Afar margin (Ethiopia) [Stile deformativo e reticolo idrografico lungo la scarpata del Plateau Somalo al margine meridionale dell’Afar (Etiopia)]
No full textAn integrated structural and geomorphologic study along the Somalian Plateau escarpment at the southern Afar margin (Dire Dawa area, Ethiopia), provides insights into the rift geometry, timing and evolution of this sector of the East Africa Rift system. Late Triassic-Jurassic sandstones and carbonate sequences lie in nonconformity over the pre-Cambrian metamorphic basement and are in turn disconformably covered by Early Cretaceous continental and transitional sandstones and conglomerates. After another disconformity a thick sequence of Flood Basalt was deposited during the Oligocene and today crop out close to the margin of the Rift at an elevation of about 3500 m in the Somalian Plateau. Rift architecture in the study area is characterized by faulted blocks tilting away from the Afar Depression «domino-style faulting», as already described by MORTON & BLACK (1975). Major faults are ca. E-W oriented and show high-angle geometry. Kinematic indicators measured along the fault planes commonly show a slight left lateral component providing a ca. NNWSSE direction of extension. Faulted monoclines composed of footwall anticline-hanging-wall syncline pairs are observed adjacent to many of the block-bounding and intra-block faults. We interpret this structural style to have formed in response to fault-propagation folding in extensional regime. The drainage pattern in the study area is strongly influenced by the main E-W trending faults and by the NNW-SSE system of fractures and doleritic dikes emplaced during the Oligocene volcanic event. Two main stages of fault activation can be recognised in the area. In fact, the faulted blocks, although usually quite dissected, sometimes have a flat top ridge preserving the remain of a former planation surface, most probably a huge pediment that connected the main escarpment to the Afar. This pediment erase some of the faults and in the distal area is covered by Early-Middle Pleistocene Afar flood basalts. After the modelling of the pediment that also cancelled the previous drainage network, a new phase of fault activity is documented. An even older drainage has been recognised in the Plateau area, where broad paleovalleys cut for over 1400 m below the original plateau in the area which separated the Afar depression from the Somalian lowlands. Originally, they were alimented from the «Afar sector» (i.e., from the north) most probably as a consequence of the upwarping that followed the emplacement of the Trap, and evolved as superimposed rivers. The northward drainage is therefore the result of river reversion as a consequence of the down-faulting associated to the rift activation and evolution. These evidence suggest that the emplacement of the Trap occurred at low elevation and was followed by upwarping and much later by rifting processes and down-faulting
Hybrid silica aerogels from bridged silicon alkoxides: ultralow thermal conductivity for low-temperature applications
No full textHybrid silica aerogels are promising materials for thermal insulation applications. Highly porous aerogels were synthesized from bridged bis(triethoxysilyl)methane BTEM and triethoxysilane TREOS silicon alkoxides via the sol‒gel process. The carbon content in the hybrid aerogels decreased with increasing amounts of TREOS. Crack-free monolith aerogels were synthesized through supercritical drying, which is crucial for thermal and optical investigations. The aerogels are characterized by high BET surface areas ranging from 700 to 1400 m2/g, pore volumes between 2.0 and 10.5 cm3/g, and a maximum porosity of 95%. The thermal conductivity of the aerogels at room temperature was measured via a hot disk apparatus. The materials exhibited ultralow thermal conductivity, reaching a minimum value of 15 mW/mK. This value ranks among the lowest reported values for silica-based aerogels in the literature. Optical transmittance measurements indicated high transparency, exceeding 80% in the visible region. Therefore, these exceptional properties of low density, high optical transparency, and low thermal conductivity make these materials promising candidates for transparent insulation applications
Bibliographie Hilarion G. Petzold 1958 – 2009 mit Anhang als Einführung
No full textDieses Archiv enthält die Gesamtbibliographie der Werke des Autors nebst einiger Texte „Über H. G. Petzold“ im Schlussteil der Bibliographie sowie einen Anhang mit einer Einführung in die Architektur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author and some texts about H. G. Petzold, moreover an epilogue with an introduction to the architecture of the works in its epistemological structure and composition and as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2009-petzold-h-g-gesamtbibliographie-h-g-petzold-1958-2009-updating-november2009/peerReviewedpublishedVersio
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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