Dynamics of a Quantum Phase Transition and Relaxation to a Steady State

We review recent theoretical work on two closely related issues: excitation of an isolated quantum condensed matter system driven adiabatically across a continuous quantum phase transition or a gapless phase, and apparent relaxation of an excited system after a sudden quench of a parameter in its Hamiltonian. Accordingly the review is divided into two parts. The first part revolves around a quantum version of the Kibble-Zurek mechanism including also phenomena that go beyond this simple paradigm. What they have in common is that excitation of a gapless many-body system scales with a power of the driving rate. The second part attempts a systematic presentation of recent results and conjectures on apparent relaxation of a pure state of an isolated quantum many-body system after its excitation by a sudden quench. This research is motivated in part by recent experimental developments in the physics of ultracold atoms with potential applications in the adiabatic quantum state preparation and quantum computation.Comment: 117 pages; review accepted in Advances in Physic

Malignant melanoma of the cerebello-pontine angle region

A case of malignant melanoma in the cerebello-pontine angle region is presented in a 72 years old female patient, who had neurological examination and CT scan suggestive of acoustic neuroma. The surgical finding and the histological examination provided the diagnosis. As a primary focus was not found on clinical examination and although autopsy was not carried out, there is a possibility of the diagnosis being a primary malignant melanoma in CNS. This specific location for this kind of tumor was found to be rare when literature is looked up

Middle cerebral artery revascularization: anatomical studies and considerations on the anastomosis site Revascularização da artéria cerebral média: estudo anatômico e considerações sobre o local de sutura

In the surgical management of skull base lesions and vascular diseases such as giant aneurysms, involvement of the internal carotid artery may require the resection or the occlusion of the vessel. The anastomosis of the external carotid artery and the middle cerebral artery with venous graft may be indicated to re-establish the blood flow. To determine the best suture site in the middle cerebral artery, an anatomical study was carried out. Fourteen cerebral hemispheres were analysed after the injection of red latex into the internal carotid artery. The superior and inferior trunk of the main division of the middle cerebral artery have more than 2 mm of diameter. They are superficial allowing an anastomosis using a venous graft. The superior trunk has a disadvantage, it gives rise to branches for the precentral and post-central giri. The anastomosis with the inferior trunk presents lower risk of neurological deficit even though the angular artery originates from it.<br>No tratamento cirúrgico das lesões da base do crânio e patologias vasculares como aneurismas gigantes, a ressecção ou oclusão da artéria carótida interna pode ser necessária. A anastomose das artérias carótida externa e cerebral média com interposição de enxerto venoso pode ser utilizada para restabelecer o fluxo sangüíneo. Para determinar o melhor local de sutura na artéria cerebral média, realizou-se um estudo anatômico. Quatorze hemisférios cerebrais foram analisados depois da injeção de látex vermelho na artéria carótida interna. Os ramos superior e inferior da divisão principal da artéria cerebral média têm mais de 2 mm de diâmetro. Eles são superficiais e permitem uma anastomose utilizando um enxerto venoso. O tronco superior tem a desvantagem de dar origem aos ramos para os giros pré e pós-centrais. A anastomose com o tronca inferior apresenta menor risco de déficit neurológico, apesar da artéria angular ter origem desse vaso