675 research outputs found
A Case Study of Using Mobile Applications and Peripherals to Encourage âReal-Lifeâ Critical Analysis in Human Physiology
This paper shares a practice of encouraging critical analysis in science students by comparing mobile applications and peripherals to traditional tools to record physiological variables such as heart rate and blood pressure. A progressive series of case studies is described with learning outcomes mapped to the benchmark statement for Bioscience from the United Kingdom's Quality Assurance Agency. A student reflection and staff commentary of the practice is also offered
Effective elastic thickness and crustal thickness variations in west central Africa inferred from gravity data
International audienceThe west central African region is characterized by various geological features: Cretaceous rifts (Benue), Tertiary domal uplift (Adamawa volcanic uplift), Tertiary-Recent volcanoes (Cameroon Volcanic Line or CVL), Tertiary sedimentary basins (Chad basins), and cratonic region (Congolese craton). In this study, we investigate the relationship between these tectonic features and the flexural rigidity of the lithosphere in Cameroon, in terms of effective elastic thickness (Te), by the use of the coherence function analysis. For that purpose, we use a new dataset of-32,000 gravity and topography points from Cameroon and the adjacent countries. The Te contour map deduced from this study shows a good relationship between the tectonic provinces and the rigidity of the lithosphere, the minima (14-20 km) are beneath the active rifted and volcanic areas (Benue, CVL, and Adamawa), and the maxima (-40 km) correspond to the Archean reworked unit in Congo. A spectral analysis of the gravity data is performed to determine the crust-mantle boundary in these tectonic provinces. The crustal thickness (Tc) contour map shows a variation from 14 km to about 45 km, consistent with other geophysical data. The lower values (14-20 km) are obtained in central Cameroon on the Adamawa uplift, and the highest values are found in southern Cameroon (Archean reworked Congolese craton). Comparing Te and Tc values shows that there is generally a positive correlation between the two parameters, with an exception in Chad where this correlation is rather negative
ACLAS â a method to define geologically significant lineaments from potential fields data
Geological features, such as faults, dikes and contacts appear as lineaments in gravity and magnetic data. The Automated Coherent Lineament Analysis and Selection (ACLAS) method is a new approach to automatically compare and combine sets of lineaments or edges derived from two or more existing enhancement techniques applied to the same gravity or magnetic data set. ACLAS can be applied to the results of any edge detection algorithms and overcomes discrepancies between techniques to generate a coherent set of detected lineaments, which can be more reliably incorporated into geological interpretation. We demonstrate that the method increases spatial accuracy, removes artefacts not related to real edges, increases stability and that it is fast to implement and execute. The direction of lower density or susceptibility can also be automatically determined representing, for example, the downthrown side of a fault. Here, ACLAS is demonstrated on magnetic anomalies calculated from a simple slab model and from a synthetic continental margin model with noise added to the result. The approach helps to identify and discount artefacts of the different techniques, although the success of the combination is limited by the appropriateness of the individual techniques and their inherent assumptions. ACLAS has been applied separately to gravity and magnetic data from the NW Australia shelf displaying results from the two data sets together helps the appreciation of similarities and differences between gravity and magnetic results and indicates the application of the new approach to large scale structural mapping. Future developments could include refinement of depth estimates for ACLAS lineaments
Comparison of social resistance to Ebola response in Sierra Leone and Guinea suggests explanations lie in political configurations not culture
Sierra Leone and Guinea share broadly similar cultural worlds, straddling the societies of the Upper Guinea Coast with Islamic West Africa. There was, however, a notable difference in their reactions to the Ebola epidemic. As the epidemic spread in Guinea, acts of violent or everyday resistance to outbreak control measures repeatedly followed, undermining public health attempts to contain the crisis. In Sierra Leone, defiant resistance was rarer. Instead of looking to âcultureâ to explain patterns of social resistance (as was common in the media and in the discourse of responding public health authorities) a comparison between Sierra Leone and Guinea suggests that explanations lie in divergent political practice and lived experiences of the state. In particular, the structures of authority in which the government-sanctioned epidemic response was channeled relate very differently to communities of trust in each country. Predicting and addressing social responses to epidemic control measures should assess such political-trust configurations when planning interventions
Constraints on non-minimally coupled curved space electrodynamics from astrophysical observations
We study interactions of electro-magnetic fields with the curvature tensor of
the form . Such
coupling terms though are invariant under general coordinate transformation and
CPT, however violate the Einstein equivalence principle. These couplings do not
cause any energy dependent dispersion of photons but they exhibit
birefringence. We put constraints on the coupling constant using
results from solar system radar ranging experiments and millisecond-pulsar
observations. We find that the most stringent constraint comes from pulsar
observations and is given by obtained from the
timing of binary pulsar PSR B1534+12.Comment: 9 pages latex, accepted in CQ
Generating a high-resolution global magnetic model for oil and mineral exploration
This is the final contribution to the trilogy of articles on global potential-field data compilations. Getech's continental and national magnetic data compilations commenced in 1989 and were designed specifically for use in petroleum and mineral exploration. These studies complemented the continental-scale gravity-compilation studies that were the subject of the TLE âMeter Readerâ contributions in March and May of this year. The success of these projects resulted from strategic partnerships, especially with Paterson, Grant and Watson Ltd. (PGW), and links to a wide range of national organizations. Early compilations covering the whole of Africa, South America, and China were followed by large-scale, small-scale, and national compilations and continue to this day with compilations of U. S. surveys. The projects spawned a range of technical developments, including approaches to remove survey-line noise, the integration of survey grids and disparate ship-track data, and the preservation of the longest-wavelength anomalies associated with the crustal magnetic field. The resulting global gravity and magnetic grids now form an invaluable resource for resource exploration
Joint analysis of the magnetic field and total gradient intensity in central Europe
In the European region, the magnetic field at satellite altitudes
(âŒ350 km) is mainly defined by a long-wavelength magnetic low,
called the Central European Magnetic Low (CEML) here, located to the southwest
of the Trans-European Suture Zone (TESZ).
We studied this area through a joint analysis of magnetic and total gradient
(âT) anomaly maps for a range of different altitudes of 5, 100 and
350 km. Tests on synthetic models showed the usefulness of the joint
analysis at various altitudes to identify reverse dipolar anomalies and to
characterize areas in which magnetization is weak. This way we identified
areas where either reversely or normally magnetized sources are locally
dominant. At a European scale these anomalies are sparse, with a low degree
of coalescence effect. The âT map indeed presents generally small
values within the CEML area, indicating that the Paleozoic Platform is
weakly magnetized.
At 350 km of altitude, the TESZ effect is largely dominant: with intense
âT highs above the East European Craton (EEC) and very small values
above the Paleozoic Platform, this again denotes a weakly magnetized
crust. Small coalescence effects are masked by the trend of the TESZ.
Although we identified sparsely located reversely magnetized sources in the
Paleozoic Platform of the CEML, the joint analysis does not support a model
of a generally reversely magnetized crust. Instead, our analysis strongly
favors the hypothesis that the CEML anomaly is mainly caused by a sharp
contrast between the magnetic properties of the EEC and Paleozoic Platform.</p
INPOP08, a 4-D planetary ephemeris: From asteroid and time-scale computations to ESA Mars Express and Venus Express contributions
The latest version of the planetary ephemerides developed at the Paris
Observatory and at the Besancon Observatory is presented here. INPOP08 is a
4-dimension ephemeris since it provides to users positions and velocities of
planets and the relation between TT and TDB. Investigations leading to improve
the modeling of asteroids are described as well as the new sets of observations
used for the fit of INPOP08. New observations provided by the European Space
Agency (ESA) deduced from the tracking of the Mars Express (MEX) and Venus
Express (VEX) missions are presented as well as the normal point deduced from
the Cassini mission. We show the huge impact brought by these observations in
the fit of INPOP08, especially in terms of Venus, Saturn and Earth-Moon
barycenter orbits.Comment: 14 pages. submitted to A&A. accepted in A&
Did Ebola emerge in West Africa by a policy-driven phase change in agroecology? Ebola's social context
SCOPUS: no.jinfo:eu-repo/semantics/publishe
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