355 research outputs found
Healthy eating promotion at the workplace: the European programme FOOD (Fighting Obesity through Offer and Demand)
VIII Congreso Iberoamericano de Nutrición. ¿Nutrición basada en la videncia o en la evidencia
On the equilibrium of a charged massive particle in the field of a Reissner-Nordstr\"om black hole
The multiyear problem of a two-body system consisting of a
Reissner-Nordstr\"om black hole and a charged massive particle at rest is here
solved by an exact perturbative solution of the full Einstein-Maxwell system of
equations. The expressions of the metric and of the electromagnetic field,
including the effects of the electromagnetically induced gravitational
perturbation and of the gravitationally induced electromagnetic perturbation,
are presented in closed analytic formulas.Comment: 9 pages, els macro
Coordinating Agile Systems through the Model-based Execution of Temporal Plans
SM thesisAgile autonomous systems are emerging, such as unmanned aerial vehicles (UAVs), that must robustly perform tightly coordinated time-critical missions; for example, military surveillance or search-and-rescue scenarios. In the space domain, execution of temporally flexible plans has provided an enabler for achieving the desired coordination and robustness, in the context of space probes and planetary rovers, modeled as discrete systems. We address the challenge of extending plan execution to systems with continuous dynamics, such as air vehicles and robot manipulators, and that are controlled indirectly through the setting of continuous state variables.Systems with continuous dynamics are more challenging than discrete systems, because they require continuous, low-level control, and cannot be controlled by issuing simple sequences of discrete commands. Hence, manually controlling these systems (or plants) at a low level can become very costly, in terms of the number of human operators necessary to operate the plant. For example, in the case of a fleet of UAVs performing a search-and-rescue scenario, the traditional approach to controlling the UAVs involves providing series of close waypoints for each aircraft, which incurs a high workload for the human operators, when the fleet consists of a large number of vehicles.Our solution is a novel, model-based executive, called Sulu, that takes as input a qualitative state plan, specifying the desired evolution of the state of the system. This approach elevates the interaction between the human operator and the plant, to a more abstract level where the operator is able to Âcoach the plant by qualitatively specifying the tasks, or activities, the plant must perform. These activities are described in a qualitative manner, because they specify regions in the plantÂs state space in which the plant must be at a certain point in time. Time constraints are also described qualitatively, in the form of flexible temporal constraints between activities in the state plan. The design of low-level control inputs in order to meet this abstract goal specification is then delegated to the autonomous controller, hence decreasing the workload per human operator. This approach also provides robustness to the executive, by giving it room to adapt to disturbances and unforeseen events, while satisfying the qualitative constraints on the plant state, specified in the qualitative state plan.Sulu reasons on a model of the plant in order to dynamically generate near-optimal control sequences to fulfill the qualitative state plan. To achieve optimality and safety, Sulu plans into the future, framing the problem as a disjunctive linear programming problem. To achieve robustness to disturbances and maintain tractability, planning is folded within a receding horizon, continuous planning and execution framework. The key to performance is a problem reduction method based on constraint pruning. We benchmark performance using multi-UAV firefighting scenarios on a real-time, hardware-in-the-loop testbed
Multifocal infantile haemangioma: a diagnostic challenge
We describe a case of a newborn who presented with multiple dark red macules that developed into red-to-purple papules associated with thrombocytopaenia. Abdominal ultrasound showed multiple hyperechoic papules and nodules. Endothelial cells from a skin biopsy stained positively for endothelial cell glucose transporter 1, which was consistent with a diagnosis of multifocal infantile haemangioma. At the age of 2?months, the child developed intestinal bleeding and anaemia. Upper and lower endoscopies showed no intestinal haemangiomas. Oral treatment with propranolol (3?mg/kg/day) resulted in complete involution of the skin and hepatic haemangiomas over the period of treatment, which lasted until the child was aged 15?months. This is a rare case of multifocal cutaneous haemangioma with hepatic and probable intestinal involvement, successfully treated with propranolol
Self-force on a scalar point charge in the long throat
An analytic method is presented which allows for the computation of the
self-force for a static particle with a scalar charge in the region of an
ultrastatic spacetime which one can call the long throat. The method is based
on the approximate WKB solution of a radial mode equation for a scalar field.
This field is assumed to be massless, with a coupling to the scalar
curvature is satisfying the condition .Comment: 11 pages, 1 figur
Overcharging a Black Hole and Cosmic Censorship
We show that, contrary to a widespread belief, one can overcharge a near
extremal Reissner-Nordstrom black hole by throwing in a charged particle, as
long as the backreaction effects may be considered negligible. Furthermore, we
find that we can make the particle's classical radius, mass, and charge, as
well as the relative size of the backreaction terms arbitrarily small, by
adjusting the parameters corresponding to the particle appropriately. This
suggests that the question of cosmic censorship is still not wholly resolved
even in this simple scenario. We contrast this with attempting to overcharge a
black hole with a charged imploding shell, where we find that cosmic censorship
is upheld. We also briefly comment on a number of possible extensions.Comment: 26 pages, 3 figures, LaTe
Photon mass and electrogenesis
We show that if photon possesses a tiny but non-vanishing mass the universe
cannot be electrically neutral. Cosmological electric asymmetry could be
generated either at an early stage by different evaporation rates of primordial
black holes with respect to positively and negatively charged particles or by
predominant capture of protons in comparison to electrons by heavy galactic
black holes in contemporary universe. An impact of this phenomenon on the
generation of large scale magnetic fields and on the universe acceleration is
considered.Comment: 15 pages, no figures, text added, typos corrected, refs. improve
Hepatocellular Carcinoma, Polymyositis, Rhabdomyolysis, and Acute Renal Failure
A 55 yr-old man presented with progressive muscle weakness and oliguria for 5days. Laboratory findings suggested rhabdomyolysis complicated with acute renal failure. A diagnosis of polymyositis was based upon the proximal muscle weakness on both upper and lower limbs, elevated muscle enzyme levels, muscle biopsy findings and the needle electromyography findings. The muscle biopsy showed extensive muscle necrosis and calcification. Investigations for underlying malignancy demonstrated hepatocellular carcinoma. The patient was managed with hemodialysis and high dose prednisolone. His renal function was fully recovered and his muscle power did improve slightly, but he died of a rupture of the hepatic tumor. In our view, this is an interesting case in that the hepatocellular carcinoma was associated with polymyositis and fulminant rhabdomyolysis-induced acute renal failure requiring hemodialysis
Successful and safe treatment of hemangioma with oral propranolol in a single institution
PurposeDramatic improvement of hemangioma to propranolol has been recently reported; however, details on dose and duration of treatment, potential risks, and monitoring have not been determined. The objective of this study is to describe and analyze the use of propranolol as a first-line treatment or as a single therapy in management of complicated hemangioma.MethodsA retrospective chart review of eight patients diagnosed with hemangioma and treated with propranolol in Kangbuk Samsung Hospital from February 2010 to April 2011 was performed.ResultsEight patients with hemangioma with functional impairment, cosmetic disfigurement, or rapid growth were treated with propranolol. Five patients had solitary facial hemangioma. The mean age of symptoms at onset was 5 weeks. The median age for starting propranolol treatment was 5.5 months. Propranolol at 2 mg/kg/day was finally administered in divided doses with a gradual increase. Significant regression was observed in seven patients, and shrinkage in size, softening in consistency, and decrease in redness were evident within 4 weeks. Among them, six patients were still taking propranolol, and one patient had stopped after 12 months. Other one patient did not show significant improvement with satisfactory result after 3 months of propranolol use. Treatment with propranolol was well tolerated and had few side effects. No rebound growth was observed in any of the patients.ConclusionWe observed that use of propranolol was very effective in treatment of hemangioma without obvious adverse effects or relapse
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