28 resultados para Data mining and knowledge discovery
Resumo:
Advances in neuroscience research over the last few decades have increased our understanding of how individual neurons acquire their specific properties and assemble into complex circuits, and how these circuits are affected in disease. One of the important motives driving neuroscience research is the development of new scientific techniques and interdisciplinary cooperation. Compared to developed countries, many countries on the African continent are confronted with poor facilities, lack of funding or career development programs for neuroscientists, all of which deter young scientists from taking up neuroscience as a career choice. This article highlights some steps that are being taken to promote neuroscience education and research in Africa.
What is "clinical data"? Why and how can they be collected during field surveys on medicinal plants?
Resumo:
ETHNOPHARMACOLOGICAL RELEVANCE: "Reverse pharmacology", also called "bedside-to-bench" or "field to pharmacy" approach, is a research process starting with documentation of clinical outcome as observed by patients with different therapeutic regimens. The treatment most significantly associated with cure is selected for future studies: first, clinical safety and efficacy; then in vivo and vitro studies. Some clinical data, i.e. details on patient status and progress, can be collected during ethnobotanical surveys; they will help clinical researchers and, once effectiveness and safety are established, will also help users of traditional medicine make safer and more effective choices. To gather clinical data successfully, ethnopharmacologists need to be backed by an appropriate team of specialists in medicine and epidemiology. Ethnopharmacologists can also gather important data on traditional medicine safety. MATERIALS AND METHODS: The first step is to create a consensus on the meaning of "clinical data", their interest and importance. An understanding of why "a cure is not a proof of effectiveness" is a starting point to avoid faulty interpretation of the clinical observations. RESULTS: Experience showed that, with the "bedside-to-bench" approach, a treatment derived from traditional recipe can be scientifically validated (in terms of safety and effectiveness) with a cost of less than a million euros, thus providing an end-product that is affordable, available and sustainable. CONCLUSIONS: With rigorous clinical study results, medicinal plant users gain the possibility to refine heath strategies. The field surveyor may gain a better relationship with the population, once she/he is seen as bringing information useful for the quality of care in the community.
Resumo:
Metabolite profiling is critical in many aspects of the life sciences, particularly natural product research. Obtaining precise information on the chemical composition of complex natural extracts (metabolomes) that are primarily obtained from plants or microorganisms is a challenging task that requires sophisticated, advanced analytical methods. In this respect, significant advances in hyphenated chromatographic techniques (LC-MS, GC-MS and LC-NMR in particular), as well as data mining and processing methods, have occurred over the last decade. Together, these tools, in combination with bioassay profiling methods, serve an important role in metabolomics for the purposes of both peak annotation and dereplication in natural product research. In this review, a survey of the techniques that are used for generic and comprehensive profiling of secondary metabolites in natural extracts is provided. The various approaches (chromatographic methods: LC-MS, GC-MS, and LC-NMR and direct spectroscopic methods: NMR and DIMS) are discussed with respect to their resolution and sensitivity for extract profiling. In addition the structural information that can be generated through these techniques or in combination, is compared in relation to the identification of metabolites in complex mixtures. Analytical strategies with applications to natural extracts and novel methods that have strong potential, regardless of how often they are used, are discussed with respect to their potential applications and future trends.
Resumo:
The Anarak, Jandaq and Posht-e-Badam metamorphic complexes occupy the NW part of the Central-East Iranian Microcontinent and are juxtaposed with the Great Kavir block and Sanandaj-Sirjan zone. Our recent findings redefine the origin of these complexes, so far attributed to the Precambrian-Early Paleozoic orogenic episodes, and now directly related to the tectonic evolution of the Paleo-Tethys Ocean. This tectonic evolution was initiated by Late Ordovician-Early Devonian rifting events and terminated in the Triassic by the Eocimmerian collision event due to the docking of the Cimmerian blocks with the Asiatic Turan block. The ``Variscan accretionary complex'' is a new name we proposed for the most widely distributed metamorphic rocks connected to the Anarak and Jandaq complexes. This accretionary complex exposed from SW of Jandaq to the Anarak and Kabudan areas is a thick and fine grain siliciclastic sequence accompanied by marginal-sea ophiolitic remnants, including gabbro-basalts with a supra-subduction-geochemical signature. New Ar-40/Ar-39 ages are obtained as 333-320 Ma for the metamorphism of this sequence under greenschist to amphibolite facies. Moreover, the limy intercalations in the volcano-sedimentary part of this complex in Godar-e-Siah yielded Upper Devonian-Tournaisian conodonts. The northeastern part of this complex in the Jandaq area was intruded by 215 +/- 15 Ma arc to collisional granite and pegmatites dated by ID-TIMS and its metamorphic rocks are characterized by Some Ar-40/Ar-39 radiometric ages of 163-156 Ma. The ``Variscan'' accretionary complex was northwardly accreted to the Airekan granitic terrane dated at 549 +/- 15 Ma. Later, from the Late Carboniferous to Triassic, huge amounts of oceanic material were accreted to its southern side and penetrated by several seamounts such as the Anarak and Kabudan. This new period of accretion is supported by the 280-230 Ma Ar-40/Ar-39 ages for the Anarak mild high-pressure metamorphic rocks and a 262 Ma U-Pb age for the trondhjemite-rhyolite association of that area. The Triassic Bayazeh flysch filled the foreland basin during the final closure of the Paleo-Tethys Ocean and was partly deposited and/or thrusted onto the Cimmerian Yazd block. The Paleo-Tethys magmatic arc products have been well-preserved in the Late Devonian-Carboniferous Godar-e-Siah intra-arc deposits and the Triassic Nakhlak fore-arc succession. On the passive margin of the Cimmerian block, in the Yazd region, the nearly continuous Upper Paleozoic platform-type deposition was totally interrupted during the Middle to Late Triassic. Local erosion, down to Lower Paleozoic levels, may be related to flexural bulge erosion. The platform was finally unconformably covered by Liassic continental molassic deposits of the Shemshak. One of the extensional periods related to Neo-Tethyan back-arc rifting in Late Cretaceous time finally separated parts of the Eocimmerian collisional domain from the Eurasian Turan domain. The opening and closing of this new ocean, characterized by the Nain and Sabzevar ophiolitic melanges, finally transported the Anarak-Jandaq composite terrane to Central Iran, accompanied by large scale rotation of the Central-East Iranian Microcontinent (CEIM). Due to many similarities between the Posht-e-Badam metamorphic complex and the Anarak-Jandaq composite terrane, the former could be part of the latter, if it was transported further south during Tertiary time. (C) 2007 Elsevier B.V. All rights reserved.
Resumo:
OBJECTIVE: As part of the WHO ICD-11 development initiative, the Topic Advisory Group on Quality and Safety explores meta-features of morbidity data sets, such as the optimal number of secondary diagnosis fields. DESIGN: The Health Care Quality Indicators Project of the Organization for Economic Co-Operation and Development collected Patient Safety Indicator (PSI) information from administrative hospital data of 19-20 countries in 2009 and 2011. We investigated whether three countries that expanded their data systems to include more secondary diagnosis fields showed increased PSI rates compared with six countries that did not. Furthermore, administrative hospital data from six of these countries and two American states, California (2011) and Florida (2010), were analysed for distributions of coded patient safety events across diagnosis fields. RESULTS: Among the participating countries, increasing the number of diagnosis fields was not associated with any overall increase in PSI rates. However, high proportions of PSI-related diagnoses appeared beyond the sixth secondary diagnosis field. The distribution of three PSI-related ICD codes was similar in California and Florida: 89-90% of central venous catheter infections and 97-99% of retained foreign bodies and accidental punctures or lacerations were captured within 15 secondary diagnosis fields. CONCLUSIONS: Six to nine secondary diagnosis fields are inadequate for comparing complication rates using hospital administrative data; at least 15 (and perhaps more with ICD-11) are recommended to fully characterize clinical outcomes. Increasing the number of fields should improve the international and intra-national comparability of data for epidemiologic and health services research, utilization analyses and quality of care assessment.
Resumo:
Quantitative information from magnetic resonance imaging (MRI) may substantiate clinical findings and provide additional insight into the mechanism of clinical interventions in therapeutic stroke trials. The PERFORM study is exploring the efficacy of terutroban versus aspirin for secondary prevention in patients with a history of ischemic stroke. We report on the design of an exploratory longitudinal MRI follow-up study that was performed in a subgroup of the PERFORM trial. An international multi-centre longitudinal follow-up MRI study was designed for different MR systems employing safety and efficacy readouts: new T2 lesions, new DWI lesions, whole brain volume change, hippocampal volume change, changes in tissue microstructure as depicted by mean diffusivity and fractional anisotropy, vessel patency on MR angiography, and the presence of and development of new microbleeds. A total of 1,056 patients (men and women ≥ 55 years) were included. The data analysis included 3D reformation, image registration of different contrasts, tissue segmentation, and automated lesion detection. This large international multi-centre study demonstrates how new MRI readouts can be used to provide key information on the evolution of cerebral tissue lesions and within the macrovasculature after atherothrombotic stroke in a large sample of patients.
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We present a new framework for large-scale data clustering. The main idea is to modify functional dimensionality reduction techniques to directly optimize over discrete labels using stochastic gradient descent. Compared to methods like spectral clustering our approach solves a single optimization problem, rather than an ad-hoc two-stage optimization approach, does not require a matrix inversion, can easily encode prior knowledge in the set of implementable functions, and does not have an ?out-of-sample? problem. Experimental results on both artificial and real-world datasets show the usefulness of our approach.