Chronic Recanalization of Dissection of the Distal Anterior Cerebral Artery: Case Report and Review of the Literature

The natural history of atraumatic idiopathic dissection of the distal anterior cerebral artery is still unclear. We present a 38-year-old man who had dissection of the left A2 segment of this vessel associated with subintimal hematoma and infarction. Because of complete stroke in acute stage, he did not undergo surgery. About three months later, administration of aspirin (100 mg/day) was started. At nine months, magnetic resonance angiography revealed complete recanalization of the A2 dissection. To assess the outcome of dissection, we should observe the patient for at least one year

Instability toward biexciton crystallization in one-dimensional electron-hole systems

One-dimensional (1D) electron-hole (e-h) systems in a high-density regime is investigated by means of bozonization techniques. It turned out that the systems are insulating even at the high density limit and that the exciton Mott transition (insulator-to-metal transition) never occurs at absolute zero temperature. The insulating ground state exhibits a strong instability towards the crystallization of biexcitons.Comment: 4 page

Small Work Space Algorithms for Some Basic Problems on Binary Images

International audienceThis paper presents space-efficient algorithms for some basic tasks (or problems) on a binary image of n pixels, assuming that an input binary image is stored in a read-only array with random-access. Although efficient algorithms are available for those tasks if O(n) work space (of O(n logn) bits) is available, we aim to propose efficient algorithms using only limited work space, i.e., O(1) or O(√n) space. Tasks to be considered are (1) CCC to count the number of connected components, (2) MERR to report the minimum enclosing rectangle of every connected component, and (3) LCCR to report a largest connected component. We show that we can solve each of CCC, MERR, and LCCR in O(n logn) time using only O(1) space. If we can use O(√n) work space, we can solve them in O(n), O(n), and O(n + m logm) time, respectively, where m is the number of pixels in the largest connected component

Priority queues and sorting for read-only data

Abstract. We revisit the random-access-machine model in which the input is given on a read-only random-access media, the output is to be produced to a write-only sequential-access media, and in addition there is a limited random-access workspace. The length of the input is N elements, the length of the output is limited by the computation itself, and the capacity of the workspace is O(S + w) bits, where S is a parameter specified by the user and w is the number of bits per machine word. We present a state-of-the-art priority queue-called an adjustable navigation pile-for this model. Under some reasonable assumptions, our priority queue supports minimum and insert in O(1) worst-case time and extract in O(N/S +lg S) worst-case time, where lg N ≤ S ≤ N/ lg N . We also show how to use this data structure to simplify the existing optimal O(N 2 /S + N lg S)-time sorting algorithm for this model