Publications by authors named "O E Walther"

Although there are some techniques for dealing with sparse and concentrated discrete data, standard time-series analyses appear ill-suited to understanding the temporal patterns of terrorist attacks due to the sparsity of the events. This article addresses these issues by proposing a novel technique for analysing low-frequency temporal events, such as terrorism, based on their cumulative curve and corresponding gradients. Using an iterative algorithm based on a piecewise linear function, our technique detects trends and shocks observed in the events associated with terrorist groups that would not necessarily be visible using other methods.

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In West Africa, long and complex livestock value chains connect producers mostly in the Sahel with consumption basins in urban areas and the coast. Regional livestock trade is highly informal and, despite recent efforts to understand animal movement patterns in the region, remains largely unrecorded. Using CILSS' database on intraregional livestock trade, we built yearly and overall weighted networks of animal movements between markets.

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The defined formation and expansion of droplets are essential operations for droplet-based screening assays. The volumetric expansion of droplets causes a dilution of the ingredients. Dilution is required for the generation of concentration graduation which is mandatory for many different assay protocols.

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Upper gastrointestinal bleeding occurred in a 64-year-old woman who was being treated with 1,000 mg acetylsalicylic acid and three times 5,000 IU heparin daily previous to a planned embolectomy because of occlusion of a lower leg artery. Radiology demonstrated multiple areas of osteolysis of the left thorax which were interpreted as recurrence of carcinoma of the breast, treated by mastectomy and radiotherapy 15 years previously. Acute renal failure, recurring severe back and abdominal pain, paraplegia of both legs and finally death from circulatory failure were explained as having been caused by multiple embolisation in the course of arteriosclerosis or a paraneoplastic increase in clotting activity.

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