Self Gravitating Fundamental Strings

We study the configuration of a typical highly excited string as one slowly increases the string coupling. The dominant interactions are the long range dilaton and gravitational attraction. In four spacetime dimensions, the string slowly contracts from its initial (large) size until it approaches the string scale where it forms a black hole. In higher dimensions, the string stays large until the coupling reaches a critical value, and then it rapidly collapses to a black hole. The implications for the recently proposed correspondence principle are discussed.Comment: 20 pages, LaTe

The entropy of black holes: a primer

After recalling the definition of black holes, and reviewing their energetics and their classical thermodynamics, one expounds the conjecture of Bekenstein, attributing an entropy to black holes, and the calculation by Hawking of the semi-classical radiation spectrum of a black hole, involving a thermal (Planckian) factor. One then discusses the attempts to interpret the black-hole entropy as the logarithm of the number of quantum micro-states of a macroscopic black hole, with particular emphasis on results obtained within string theory. After mentioning the (technically cleaner, but conceptually more intricate) case of supersymmetric (BPS) black holes and the corresponding counting of the degeneracy of Dirichlet-brane systems, one discusses in some detail the ``correspondence'' between massive string states and non-supersymmetric Schwarzschild black holes.Comment: 51 pages, 4 figures, talk given at the "Poincare seminar" (Paris, 6 December 2003), to appear in Poincare Seminar 2003 (Birkhauser

Venous Sinus Thrombosis in Lemierre's Syndrome

Pseudotumor cerebri is characterized by increased intracranial pressure without a space-occupying lesion. Associated causes include cranial venous obstruction. We present a case of pseudotumor cerebri in Lemierre's syndrome. Lemierre's syndrome is an acute oropharyngeal infection with septic thrombophlebitis of the internal jugular vein. In our patient the thrombophlebitis extended intracranially to include the saggital, sigmoid, and straight sinuses

Temporal Arteroma

Loss of vision OSA 69-year old female with an 11-day history of progressive loss of vision OS. Previous history significant for mild chronic leukopenia.VA: 20/20 OD, NLP OS; Color plates 11/15 ODMRIAggregates of small cell immature atypical lymphocytes with clumped chromatin; Elevated ESRIV corticosteroidsAttache

Hydrocephalus Secondary to Isolated Spinal Cysticerosis

Hydrocephalus is a common complication of Neurocysticercosis and is usually due to obstruction by cisternal or ventricular cysts, or subarachnoid spaces by diffuse basilar meningitis. Spinal cysticercosis is an uncommon manifestation seen in 0.7 to 6% of cases. It is thought to be due to downward migration of larvae from the cerebral to the spinal subarachnoid spaces with possible ventriculoependymal infiltration or hematogenous dissemination. We report the unusual case of isolated spinal involvement leading to hydrocephalus

Bitemporal Superior Quadrantic Defects Associated with an Anomalous A1

Bitemporal superior quadrantic defects are thought to be secondary to lesions disrupting inferonasal retinal fibers as they decussate in the anterior chiasm. They can be seen with compressive lesions such as pituitary adenomas, meningiomas, or anterior cerebral artery aneurysms most commonly

Familial Isolated Foveal Hypoplasia Simulating Hereditary Congenital Nystagmus and Gaze Holding Failure

Usually associated with other ocular anomalies, isolated foveal hypoplasia is a rare developmental defect In addition to decreased vision, nystagmus is a prominent feature of the condition

Optic Neuropathy in Systemic Lupus Erythematosus: MRI Characteristics

Central nervous system involvement in systemic lupus erythematous (SLE) has been estimated to occur in 30% to 40% of patients. Though less common, optic nerve disease can be seen in 1% of those patients with SLE. Gadolinium enhanced Magnetic Resonance Imaging (MRI) has increased the sensitivity in evaluating CNS lesions. Two reports of the MRI characteristics of optic neuropathy in SLE were normal although Gadolinium contrast was not used