Search results for "Laboratory"
showing 10 items of 923 documents
ACQUISITION OF STUDENT SCIENTIFIC INQUIRY SKILLS: CENTRALISED EXAMINATION RESULTS IN CHEMISTRY
2016
From 2011, the new educational standard in Latvia in the framework of the educational reform on the centralised examination (CE) in chemistry stipulates students to demonstrate the inquiry skills they have mastered. The purpose of this study is to find out the students’ inquiry skills by analysing the CE results in chemistry. This study addresses the following research questions: (a) To what extent are the centralised examination inquiry skills measured according to the standard outcomes? (b) What information on how students have mastered the inquiry skills in chemistry is available from the CE results for the period of 2011-2015? (c) Does measuring the inquiry skills using inquiry-based la…
Electron crystallography and non-linear optics
1999
Electron crystallography can be used to obtain specific information about molecular parameters such as the polarisability, dipole moment, and hyperpolarisability. In this, work we show how a combination of quantum mechanics and simulation methods can be used to solve several unknown organic structures and how the calculated molecular parameters can be used to predict the corresponding physical properties of the crystals.
User-oriented evaluation of mechanical single-channel axial pipettes.
2013
Hand tools should be designed so that they are comfortable to use, fit the hand and are user-oriented. Six different manual, single-channel axial pipettes were evaluated for such objective outcomes as muscular activity, wrist postures and efficiency, as well as for subjective outcomes concerning self-assessed features of pipette usability and musculoskeletal strain. Ten experienced laboratory employees volunteered for the study. The results showed that light and short pipettes with better tool comfort resulted in reduced muscular activity and perceived musculoskeletal strain when they were compared with a long and heavy pipette. There were no differences in the efficiency between the differ…
Inter-laboratory evaluation of the ISO standard 11063 "Soil quality -- Method to directly extract DNA from soil samples"
2011
International audience; Extracting DNA directly from micro-organisms living in soil is a crucial step for the molecular analysis of soil microbial communities. However, the use of a plethora of different soil DNA extraction protocols, each with its own bias, makes accurate data comparison difficult. To overcome this problem, a method for soil DNA extraction was proposed to the International Organization for Standardization (ISO) in 2006. This method was evaluated by 13 independent European laboratories actively participating in national and international ring tests. The reproducibility of the standardized method for molecular analyses was evaluated by comparing the amount of DNA extracted, …
Circulating markers of retinal and optic nerve lipids
2013
Purpose Blood lipids are frequently used as a surrogate of lipid composition of peripheral tissues. Even if it is well accepted, such a relationship has never been clearly demonstrated for the eye. The aim of this study was to determine in human samples whether a lipidomic approach based on red blood cells could reveal associations between circulating and ocular lipid profiles. Methods Red blood cells, retinas and optic nerves were collected from 9 human donors. The lipidomic analyses on these tissues were done by both, gas chromatography and liquid chromatography coupled to an electrospray ionization source-mass spectrometer (LC-ESI-MS/MS). Results Gas chromatographic approach did not show…
An Ontology-Based Approach for the Reconstruction and Analysis of Digital Incidents Timelines
2015
International audience; Due to the democratisation of new technologies, computer forensics investigators have to deal with volumes of data which are becoming increasingly large and heterogeneous. Indeed, in a single machine, hundred of events occur per minute, produced and logged by the operating system and various software. Therefore, the identification of evidence, and more generally, the reconstruction of past events is a tedious and time-consuming task for the investigators. Our work aims at reconstructing and analysing automatically the events related to a digital incident, while respecting legal requirements. To tackle those three main problems (volume, heterogeneity and legal require…
Can we Trust Untargeted Metabolomics: Results of the Metabo-ring Initiative, a Large-scale Multi-instruments Inter-laboratoire Study
2013
This work was presented at the 6th Journée Scientifique du Réseau Français de Métabolomique et Fluxomique, Nantes, May 2012 and at the 8th International Conference of the Metabolomics Society, Washington, June 2012This work was presented at the 6th Journée Scientifique du Réseau Français de Métabolomique et Fluxomique, Nantes, May 2012 and at the 8th International Conference of the Metabolomics Society, Washington, June 2012; The metabo-ring initiative brought together five nuclear magnetic resonance instruments (NMR) and 11different mass spectrometers with the objective of assessing the reliability of untargeted metabolomics approaches in obtaining comparable metabolomics profiles. This wa…
Ether-lipid and docosahexaenoic acid (DHA) levels in erythrocytes of patients with glaucoma
2008
International audience; Purpose: : Neuronal tissues such as the brain and the retina are known to contain elevated amounts of phospholipids with a vinyl-ether double bond (ether-lipids or plasmalogens) as well as high concentrations of long-chain omega-3 polyunsaturated fatty acids (docosahexaenoic acid or DHA). Abnormal blood levels of ether-lipids and DHA have been associated with several neurological disorders such as Alzheimer Disease. Since many observations bring up the idea of pathogenetic similarities between Alzheimer Disease and glaucoma, the aim of our work was to check whether ether-lipid and DHA levels were modified in glaucoma patients. Methods: : Blood samples were collected …
Quantification of land-atmosphere exchanges of water, energy and carbon dioxide in space and time over the heterogeneous Barrax site
2008
International audience; To advance our understanding of land-atmosphere exchanges of water, energy and carbon dioxide (CO2) in space and time over heterogeneous land surfaces, two intensive field campaigns were carried out at the Barrax agricultural test site in Spain during 12-21 July 2004 (SPARC 2004) and 8-14 July 2005 (SEN2FLEX 2005) involving multiple field, satellite and airborne instruments for characterizing the state of the atmosphere, the vegetation and the soil from the visible to the microwave range of the spectrum. Part of the experimental area is a core site of area 25 km2, within which numerous crops are grown, on both irrigated and dry land, alongside fields of bare soil. Th…