986 research outputs found
Biopsym : a learning environment for transrectal ultrasound guided prostate biopsies
This paper describes a learning environment for image-guided prostate
biopsies in cancer diagnosis; it is based on an ultrasound probe simulator
virtually exploring real datasets obtained from patients. The aim is to make
the training of young physicians easier and faster with a tool that combines
lectures, biopsy simulations and recommended exercises to master this medical
gesture. It will particularly help acquiring the three-dimensional
representation of the prostate needed for practicing biopsy sequences. The
simulator uses a haptic feedback to compute the position of the virtual probe
from three-dimensional (3D) ultrasound recorded data. This paper presents the
current version of this learning environment
Safety culture as a rational myth: why developing safety culture implies engineering resilience?
Available on: http://www.resilience-engineering.org/REPapers/Chevreau_R.pdfInternational audienceWork on resilience engineering has stimulated an ever growing interest illustrated by the increasing number of publications on the subject. While at the same time, the older notion of safety culture continues to interest scientists and practitioners. The purpose of this article is to build a managerial approach of safety culture which takes in resilience engineering. It first describes the epistemological background of this approach based on intervention-research. This aims at introducing the notion of "rational myth" that describes the principles on which organized action bases itself at a given time. Secondly, the article identifies and presents three managerial principles on which risk mastering is centered: the principle of responsibility, the principle of anticipation and the principle of resilience. It then shows that the notion of safety culture as historically defined after the Chernobyl disaster and taken into account by managers can be analyzed as a rational myth for risk mastering including these three principles. It illustrates this by an example taken from an intervention led in partnership with the French pharmaceutical company Sanofi-Aventis. The article finally concludes that developing safety culture is more adapted to risk mastering principles than engineering resilience
BiopSym: a simulator for enhanced learning of ultrasound-guided prostate biopsy
This paper describes a simulator of ultrasound-guided prostate biopsies for
cancer diagnosis. When performing biopsy series, the clinician has to move the
ultrasound probe and to mentally integrate the real-time bi-dimensional images
into a three-dimensional (3D) representation of the anatomical environment.
Such a 3D representation is necessary to sample regularly the prostate in order
to maximize the probability of detecting a cancer if any. To make the training
of young physicians easier and faster we developed a simulator that combines
images computed from three-dimensional ultrasound recorded data to haptic
feedback. The paper presents the first version of this simulator
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New formulation of mechanical specific energy (MSE) taking into account the hydraulic effects for PDC bits
In today’s unstable economic environment, the cost of drilling continues to be the most important limitation factor to drill new wells. Thus, to reach the deepest depth at the lowest price, drilling needs to be optimized. To do so, drillers monitor two values: the rate of penetration (ROP) and the mechanical specific energy (MSE). However, MSE has been proven to be more valuable because it links ROP with drilling parameters as weight on bit (WOB) or torque. Moreover, it allows computation of mechanical efficiency (EFFM), which is directly linked to the drilling efficiency. The latest MSE formulations only consist of three components: a thrust one, a rotary one and a hydraulic one, which only represents the action of the jet impacts. The associated mechanical efficiency consists of the minimum MSE (MSEmin) divided by the actual MSE. This formulation has been proven to be inaccurate by several authors. In fact, they showed that as hydrostatic pressure increases, the mechanical efficiency decreases. This decrease has been explained by these authors by the fact that some important hydraulic phenomena are not considered. These phenomena are the shear dilatancy and change in failure mechanism. Shear dilatancy is the phenomenon that happens when the drill bit shears the rock: the rock dilates which causes a decrease in pore pressure and thus an increase in differential pressure which strengthens the rock. This strengthening has been quantified and MSE has been reformulated to take into account this phenomenon. At atmospheric conditions, the failure mechanism is usually brittle, creating chip like cutting. However, when applying hydrostatic pressure this failure mode switches towards the ductile mode creating ribbon like cutting. The formulation of the MSEmin has been adapted to take into consideration this phenomenon. In order to help an engineer to take into account these phenomena, a program was developed that shows graphically and quantitatively the influence of these mechanisms. The program allows the user to vary several parameters and is capable of extracting drilling data from an existing Excel sheet. This is important since the influence of these mechanisms can create differences of around 10% between the efficiencies calculated with and without considering these phenomena, and this difference can reach values over 20% in certain formationsPetroleum and Geosystems Engineerin
On the structure of contraction operators. I
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27438/1/0000476.pd
Expression of a bacterial effector, harpin N, causes increased resistance to fire blight in Pyrus communis
The rapid and effective activation of disease resistance responses is essential for plant defense against pathogen attack. These responses are initiated when pathogen-derived molecules (elicitors) are recognized by the host. In order to create novel mechanisms for fire blight resistance in pear, we have generated transgenic pears expressing the elicitor harpin Nea from Erwinia amylovora under the control of the constitutive promoter CaMV35S. The transient expression of hrpN Ea in pear cells did not provoke any apparent damage. Therefore, stable constitutive expression of hrpN Ea was studied in seventeen transgenic clones of the very susceptible cultivar "Passe Crassane.” Most transgenic clones displayed significant reduction of susceptibility to fire blight in vitro when inoculated by E. amylovora, which was positively correlated to their degree of expression of the transgene hrpN Ea . These results indicate that ectopic expression of a bacterial elicitor such as harpin Nea is a promising way to improve pear resistance to fire bligh
On the structure of contraction operators. II
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27446/1/0000486.pd
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Federalism & post-conflict statebuilding: The case of Somalia
The use of federalism as an integral component in post-conflict statebuilding processes is becoming increasingly common (e.g. Iraq, Yemen & Sri Lanka). The current academic literature, however, is divided between those that argue that federalism in such fragile environments will increase the likelihood of secession and ‘balkanisation’ and that those that argue that only federalism can provide the periphery with constitutionally protected rights against the centre. However, currently there is little empirical evidence to support either view. This research seeks to contribute to this gap by assessing whether the recent introduction of federalism in Somalia since 2013 has led to the delivery of tangible governance and peacebuilding outcomes.
This thesis specifically focuses on the federalism process in Jubaland, a state which formed in 2013. Data was gathered across the region using a statistically significant perception survey and was supplemented by Key Informant Interviews. The surveys were designed to assess public opinion towards federalism and understand how its introduction was perceived to have impacted local governance and conflict dynamics. This analysis was further extended to assess the impact of federalism in other federal member states including Puntland, Galmadug and Southwest based on a review of available secondary literature. An analytical framework assessed the strength of Federal Government-Federal Member State, intra-state and inter-state relations and the extent to which a particular state had undertook tangible governance reforms.
The key findings of the research indicate that the population in Jubaland is strongly supportive of federalism in principle and the manner in which it has been implemented. Federalism was seen by the majority of the population as a way of maintaining Somali unity whilst protecting local interests and meeting ocal needs. The approach of the Jubaland authorities to adopt a consociational approach to governance led to the establishment of a sustainable political settlement and the inclusion of minority groups for the first time.
However, these successes have not been experienced more widely across Somalia. Other federal member states have experienced poor relations with the federal government. Internally, some states also have weak and violent relations with groups who are competing for influence and poor external relationships with other federal member states. In general, there is a low commitment to governance reform at federal-state level.
These findings underpin the final conclusion that whilst federalism in Somalia has enabled improved governance and peacebuilding outcomes in Jubaland, it is the manner of how federal governance has been implemented in other federal states that explains the disparity in results across the country as a whole. More widely, this research suggests that federalism in post-conflict contexts is neither a panacea for peace and stability, or in of itself, a catalyst for inevitable fragmentation
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