810 research outputs found
Post-test simulations for the NACIE-UP benchmark by STH codes
This paper illustrates the results obtained in the last phase of the NACIE-UP benchmark activity foreseen inside the EU SESAME Project. The purpose of this research activity, performed by system thermal–hydraulic (STH) codes, is finalized to the improvement, development and validation of existing STH codes for Heavy Liquid Metal (HLM) systems. All the participants improved their modelling of the NACIE-UP facility, respect to the initial blind simulation phase, adopting the actual experimental boundary conditions and reducing as much as possible sources of uncertainty in their numerical model. Four different STH codes were employed by the participants to the benchmark to model the NACIE-UP facility, namely: CATHARE for ENEA, ATHLET for GRS, RELAP5-3D© for the “Sapienza” University of Rome and RELAP5/Mod3.3(modified) for the University of Pisa. Three reference tests foreseen in the NACIE-UP benchmark and carried out at ENEA Brasimone Research Centre were analysed from four participants. The data from the post-test analyses, performed independently by the participant using different STH codes, were compared together and with the available experimental results and critically discussed
The state of Texas vs the Methodist hospital system: An accounting case study: Working paper series--99-02
Pressures to contain costs have given private hospitals the economic incentive to reduce provision of charity care services, shifting the burden onto government hospitals. Budget pressures on governmental units have produced resistance to any further shift in charity care burden. We observe in a lawsuit (State of Texas vs. Methodist Hospital System [MHS]) what appears to be a classic moral hazard situation. The government expects a certain (unspecified) level of charity care to be performed in exchange for tax exemptions; hospital management allegedly consumes perquisites and overstates reported charity care figures. Both sides use accounting numbers to defend their positions. The Case makes five contributions. First, it is relevant and flexible enough for use in several different accounting or business courses, including financial, audit, tax, not-for-profit, or ethics courses. Second, it provides students an introduction to not-for-profit accounting placed in an interesting and relevant context. Third, students must employ forensic skills, much as did the state attorney general. Fourth, the Case requires students to make several audit-related determinations, including knowledge of a client's business, fraud, and related-party transactions. Finally, as students progress through the case, they are required to consider several ethical issues
Label-based Optimization of Dense Disparity Estimation for Robotic Single Incision Abdominal Surgery
Minimally invasive surgical techniques have led to novel approaches such as Single Incision Laparoscopic Surgery (SILS), which allows the reduction of post-operative infections and patient recovery time, improving surgical outcomes. However, the new techniques pose also new challenges to surgeons: during SILS, visualization of the surgical field is limited by the endoscope field of view, and the access to the target area is limited by the fact that instruments have to be inserted through a single port.
In this context, intra-operative navigation and augmented reality based on pre-operative images have the potential to enhance SILS procedures by providing the information necessary to increase the intervention accuracy and safety. Problems arise when structures of interest change their pose or deform with respect to pre-operative planning, as usually happens in soft tissue abdominal surgery. This requires online estimation of the deformations to correct the pre-operative plan, which can be done, for example, through methods of depth estimation from stereo endoscopic images (3D reconstruction). The denser the reconstruction, the more accurate the deformation identification can be.
This work presents an algorithm for 3D reconstruction of soft tissue, focusing on the refinement of the disparity map in order to obtain an accurate and dense point map. This algorithm is part of an assistive system for intra-operative guidance and safety supervision for robotic abdominal SILS .
Results show that comparing our method with state-of-the-art CPU implementations, the percentage of valid pixel obtained with our method is 24% higher while providing comparable accuracy. Future research will focus on the development of a real-time implementation of the proposed algorithm, potentially based on a hybrid CPU-GPU processing framework
Virtual Assistive System for Robotic Single Incision Laparoscopic Surgery
Single Incision Laparoscopic Surgery (SILS) reduces
the trauma of large wounds decreasing the post-operative infections,
but introduces technical difficulties for the surgeon, who has
to deal with at least three instruments in a single incision. These
drawbacks can be overcome with the introduction of robotic
arms inside the abdominal cavity, but still remain difficulties in
the surgical field vision, limited by the endoscope field of view.
This work is aimed at developing a system to improve the information
required by the surgeon and enhance the vision during
a robotic SILS. In the pre-operative phase, the segmentation and
surface rendering of organs allow the surgeon to plan the surgery.
During the intra-operative phase, the run-time information (tools
and endoscope pose) and the pre-operative information (3D
models of organs) are combined in a virtual environment. A
point-based rigid registration of the virtual abdomen on the real
patient creates a connection between reality and virtuality. The
camera-image plane calibration allows to know at run-time the
pose of the endoscopic view.
The results show how using a small set of 4 points (the minimal
number of points that would be used in a real procedure) for the
camera-image plane calibration and for the registration between
real and virtual model of the abdomen, is enough to provide a
calibration/registration accuracy within the requirements
TOpic: rare and special cases, the real "Strange cases"
Introduction: The bladder hernia represents approximately 1-3% of
all inguinal hernias, where patients aged more than 50 years have a
higher incidence (10%). Many factors contribute to the development of a bladder hernia,
including the presence of a urinary outlet obstruction causing chronic
bladder distention, the loss of bladder tone, pericystitis, the perivesical
bladder fat protrusion and the obesity
Influence of hyperhomocysteinemia on the cellular redox state - Impact on homocysteine-induced endothelial dysfunction
Hyperhomocysteinemia is an independent risk factor for the development of atherosclerosis. An increasing body of evidence has implicated oxidative stress as being contributory to homocysteines deleterious effects on the vasculature. Elevated levels of homocysteine may lead to increased generation of superoxide by a biochemical mechanism involving nitric oxide synthase, and, to a lesser extent, by an increase in the chemical oxidation of homocysteine and other aminothiols in the circulation. The resultant increase in superoxide levels is further amplified by homocysteinedependent alterations in the function of cellular antioxidant enzymes such as cellular glutathione peroxidase or extracellular superoxide dismutase. One direct clinical consequence of elevated vascular superoxide levels is the inactivation of the vasorelaxant messenger nitric oxide, leading to endothelial dysfunction. Scavenging of superoxide anion by either superoxide dismutase or 4,5-dihydroxybenzene 1,3-disulfonate (Tiron) reverses endothelial dysfunction in hyperhomocysteinemic animal models and in isolated aortic rings incubated with homocysteine. Similarly, homocysteineinduced endothelial dysfunction is also reversed by increasing the concentration of the endogenous antioxidant glutathione or overexpressing cellular glutathione peroxidase in animal models of mild hyperhomocysteinemia. Taken together, these findings strongly suggest that the adverse vascular effects of homocysteine are at least partly mediated by oxidative inactivation of nitric oxide
Documenting Surface and Sub-surface Volatiles While Drilling in Frozen Lunar Simulant
NASA's Resource Prospector (RP) mission is intended to characterize the three-dimensional nature of volatiles in lunar polar regions and permanently shadowed regions. RP is slated to carry two instruments for prospecting purposes. These include the Neutron Spectrometer System (NSS) and Near-Infrared Volatile Spectrometer System (NIRVSS). A Honybee Robotics drill (HRD) is intended to sample to depths of 1 m, and deliver a sample to a crucible that is processed by the Oxygen Volatile Extraction Node (OVEN) where the soil is heated and evolved gas is delivered to the gas chromatograph / mass spectrometer of the Lunar Advanced Volatile Analysis system (LAVA). For several years, tests of various sub-systems have been undertaken in a large cryo-vacuum chamber facility (VF-13) located at Glenn Research Center. In these tests a large tube (1.2 m high x 25.4 cm diameter) is filled with lunar simulant, NU-LHT-3M, prepared with known abundances of water. There are thermo-couples embedded at different depths, and also across the surface of the soil tube. The soil tube is placed in the chamber and cooled with LN2 as the pressure is reduced to approx.5-6x10(exp -6) Torr. Here we discuss May 2016 tests where two soil tubes were prepared and placed in the chamber. Also located in the chamber were 5 crucibles, an Inficon mass spectrometer, and a trolly permitting x-y translation, where the HRD and NIRVSS, were mounted. The shroud surrounding the soil tube was held at different temperatures for each tube to simulate a warm and cold lunar environment
Global Outsourcing of Healthcare: A Medical Tourism Decision Model
The demand for global healthcare services is experiencing tremendous growth. US patients are seeking to reduce their expenditures on healthcare through obtaining treatment on an internationally competitive basis. This trend, known as medical tourism, is on the rise, and US legislators and policy makes must be aware of the issues facing American patients. This paper seeks to model factors that influence a patient's decision to seek healthcare services abroad. we develop a two-stage model for medical tourism- the first stage being the evaluation of the foreign country and the second stage choosing the healthcare facility. We argue country-specific characteristics influence the country of choice-including economic condition, political climate, and regulatory policies. We also argue that certain factors- including costs, hospital accreditaion, quality of care, and physician trining- impact the choice of healthcare facility. The model suggests that no one factor is dominant in the decision, but all play a crucial role in choosing healthcare on an international basis. Policy makers must use these factors to evaluate the impact medical tourism will continuw to have on the US healtcare system in order to effectively compete in today's global, consumer-driven healthcare market.Medical tourism; global outsourcing; decision model; health care system; healthcare services; health policy; health costs
Pre-test analysis of thermal-hydraulic behaviour of the NACIE facility for the characterization of a fuel pin bundle
This report, carried out at the DIMNP (Dipartimento di Ingegneria Meccanica, Nucleare e della Produzione) of the University of Pisa in collaboration with ENEA Brasimone Research Centre, illustrates the pre-test thermo-fluidynamic analysis of the NACIE (Natural Circulation Experiment) facility, built at ENEA, in its new configuration of the heat exchanger and of the heater system. In particular, the first part of the work regards the study performed by RELAP5/Mod3.3 system code, modified in order to take into account LBE fluid properties and the appropriate convective heat transfer correlations. The code was employed to support the design of SEARCH experimental campaign, devoted to characterize the performance of a wire spaced fuel bundle relevant for MYRRHA facility (i.e. heat exchange and pressure drop) in shutdown conditions and providing data for code validation. For this purpose, low heat power simulations on NACIE facility have been performed to investigate the established loop natural flow rate and related parameters for increasing values of loop hydraulic resistance. The second part of the work concerns the first application, to a simplified representation of NACIE facility, of the coupling between the RELAP5 thermal-hydraulic system code and the CFD Fluent commercial code. Preliminary comparative analysis among the simulations performed by RELAP5-Fluent coupled codes and by RELAP5 stand-alone code showed very good agreement among them, giving confidence to this innovative coupling strategy.
Countering the Australian 'ndrangheta: The criminalisation of mafia behaviour in Australia between national and comparative criminal law
Mafia-type criminal groups belonging to, or originated from, the Calabrian ‘ndrangheta from Southern Italy, have been object of recent academic research and media attention in Australia. The Australian ‘ndrangheta, as qualified form of organised crime, poses new challenges for law enforcement in the country. This paper briefly looks at the strategies to fight organised crime in Australia, with specific focus on anti-association laws. By using a comparative approach, the paper will look at the criminalisation of mafias as qualified forms of organised crime in other two jurisdictions, Italy and the USA, to advocate for an effective mafia criminalisation in Australia. In conclusion, this paper will argue that, in order to also fight mafia phenomena, criminal law in Australia should focus on behaviours of organised crime groups rather than only on the criminalisation of proscribed associations and their illegal activities
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