Calibration of parameters in Dynamic Energy Budget models using Direct-Search methods.

Dynamic Energy Budget (DEB) theory aims to capture the quantitative aspects of metabolism at the individual level, for all species. The parametrization of a DEB model is based on information obtained through the observation of natural populations and experimental research. Currently the DEB toolbox estimates these parameters using the Nelder-Mead Simplex method, a derivative-free direct-search method. However, this procedure presents some limitations regarding convergence and how to address constraints. Framed in the calibration of parameters in DEB theory, this work presents a numerical comparison between the Nelder-Mead Simplex method and the SID-PSM algorithm, a Directional Direct-Search method for which convergence can be established both for unconstrained and constrained problems. A hybrid version of the two methods, named as Simplex Directional Direct-Search, provides a robust and efficient algorithm, able to solve the constrained optimization problems resulting from the parametrization of the biological models.

Minimally invasive approach to traumatic intracerebral hematomas.

Trauma is one of the leading causes of death in Brazil. We report on 28 cases of traumatic intracerebral hematomas operated on via a minimally invasive approach. A simplified method of localization and right placement of the burr hole is described in details, as well as the technique used in all cases. Every patient was submitted to pre- and postoperative CT scan (computerized tomography) and had the volume of the hematoma measured before the surgical procedure to compare the efficacy of the treatment. No patient needed a second operation, even though in some cases there were residual hematomas. We believe that this approach can be done with safety and replace a standard craniotomy in selected cases.

[Tethered spinal cord syndrome: report of 2 cases]. / Síndrome da medula presa: registro de dois casos.

The tethered spinal cord syndrome is a disease that is part of the group of spinal dysraphisms, that was recently recognized as an individualized nosological entity, yet not frequently diagnosed among us. It is characterized by shortening and thickening of the filum terminale which prevents the ascent of the spinal cord into spinal canal, the conus medularis abnormally remaining in a low place. It is associated in all cases with spina bifida. The diagnosis is simple, once the disease is suspected. It is manifested by progressive motor or sensory deficit in the legs, urinary incontinence, scoliosis and leg or back pain, specially in young children. The plain lumbosacral RX always shows spina bifida. Myelography makes the diagnostic. It shows, basically, the negative image of the thickened filum terminale and the low placed conus medularis. Other exams which can help are the computerized tomography and the ultra-sound of the spinal cord. The surgical treatment is very simple and heals without sequels if done in due time. It consists in a sectioning of the filum terminale through laminectomy. Two cases diagnosed and treated at Hospital da Baleia, from Fundação Benjamin Guimarãcs, Belo Horizonte, are reported in this paper.

Bilateral intracavernous carotid aneurysms: treatment by bilateral carotid ligation.

Bilateral carotid ligation was performed successfully in a patient who had bilateral aneurysms of the intracavernous portion of the carotid artery. The left common carotid artery was ligated for treatment of an intracavernous aneurysm. Three years later, as the patient developed signs of a contralateral cavernous sinus aneurysm, the right carotid artery was partially occluded. Except for a slight right ptosis and a limitation of vertical gaze, the neurological signs subsided completely.