A multi-site campaign to measure solar-like oscillations in Procyon. II. Mode frequencies

We have analyzed data from a multi-site campaign to observe oscillations in the F5 star Procyon. The data consist of high-precision velocities that we obtained over more than three weeks with eleven telescopes. A new method for adjusting the data weights allows us to suppress the sidelobes in the power spectrum. Stacking the power spectrum in a so-called echelle diagram reveals two clear ridges that we identify with even and odd values of the angular degree (l=0 and 2, and l=1 and 3, respectively). We interpret a strong, narrow peak at 446 muHz that lies close to the l=1 ridge as a mode with mixed character. We show that the frequencies of the ridge centroids and their separations are useful diagnostics for asteroseismology. In particular, variations in the large separation appear to indicate a glitch in the sound-speed profile at an acoustic depth of about 1000 s. We list frequencies for 55 modes extracted from the data spanning 20 radial orders, a range comparable to the best solar data, which will provide valuable constraints for theoretical models. A preliminary comparison with published models shows that the offset between observed and calculated frequencies for the radial modes is very different for Procyon than for the Sun and other cool stars. We find the mean lifetime of the modes in Procyon to be 1.29 +0.55/-0.49 days, which is significantly shorter than the 2-4 days seen in the Sun.Comment: accepted for publication in Ap

Neuro-Ophthalmology and Lymphocytic Hypophysitis

Lymphocytic hypophysitis is a rare inflammatory disorder affecting the sellar region. LH typically presents in the third trimester of pregnancy, although nulliparous and male patients have been reported. Two cases of LH with neuroophthalmologic symptoms will be presented

Divided We Stand

Vertical diplopia; Balance difficultiesA 56-year old female with vertical diplopia and mild balance difficulty.VA: Best-corrected, 20/20 OD, 20/15 OS; Color plates: 8.5/10 OD, 9.5/10 OS.MRIEpendymal cystSurgeryAttache

Oculopalatal Tremor with Delayed Onset Ataxia

Oculopalatal myoclonus, more accurately described as oculopalatal tremor (OPT), consists of penduiar nystagmus with palatal tremor. OPT typically presents in a delayed fashion (median: ~10 months; range: 0 - 49 months) following an acute brainstem lesion. Although patients with OPT often exhibit symptoms related to the initial insult, the delayed sequelae are typically restricted to the eyes and palate

Asymetric Papilledema in Idiopathic Intracranial Hypertension: An Insight

Papilledema may be asymmetric or unilateral. Proposed mechanisms have included asymmetric intraocular pressure and anatomical variations in the optic nerve sheaths, such as adhesions or leaks that prevent transmission of intracranial pressure along one nerve

Neuromyelitis Optica

Eugene Devic and his student F. Gault first reported a single case of their own and reviewed 16 existing cases characterized by optic neuropathy and myelopathy . in 1894. The disease has been considered by some investigators to be a variant of multiple sclerosis MS; (clinically definite MS = CDMS), although it appears to follow a s~parate and distinct course. This paper will review the current clinical, pathophysiologic, and therapeutic facets of Devic's neuromyelitis optica (DNO)

Walsh & Hoyt: Familial Creutzfeldt-Jakob Disease

The clinical features of familial CJD (fCJD) are indistinguishable from those of sCJD, including the visual manifestations. Homonymous visual field defects occur in some patients with fCJD, as does cerebral blindness. Nicholl et al. described a family with a 144base pair insertion (6octapeptide repeat) in whom the initial presentation of CJD was visual disturbance and unsteadiness. The propositus of the family was only able to recognize light and dark at the time of his admission 2 months after symptoms began; cognitive decline and myoclonic jerks followed shortly thereafter. An EEG revealed typical synchronous triphasic discharges, and death occurred 1 month after admission. Bertoni et al. described supranuclear paralysis of vertical gaze in several patients with familial CJD who had a mutation at codon 200. Among the patients described by Collinge et al., one patient was said to have had ""pale optic discs"" and perhaps a right homonymous hemianopia. Another patient had ""twitching of the eyelids,"" whereas a third patient had ""blepharoclonus."" A fourth patient was unable to complete tasks, particularly those requiring ""visuospatial skills."" Although these investigators did not describe any specific disorders of eye movement in any of the affected family members, a variety of disturbances of fixation, pursuit, and saccades were likely present in most of them as well as in the affected patients reported by Capellari and by Poulter et al

How to Capture Disease Activity in the Longitudinal Follow-Up of Optic Neuropathies?

Optic neuropathy is a common neuro-ophthalmic diagnosis. Although it is often easy enough to recognize and anatomically localize in its typical forms, it is more challenging to precisely follow for any significant change over time. Many of the tools we use to evaluate and follow optic nerve function are psychophysical such as acuity and perimetry, and accordingly suffer from subjectivity and variability-related errors. The pupil is useful in optic nerve assessment, and although objectively judged by the physician, it is infrequently quantified, and thus less suitable as a long-term follow up marker. Imaging and electrophysiology provide objective metrics for optic nerve anatomy and physiology, but may be cumbersome, expensive, or demonstrate unfavorable sensitivity, specificity and variability across clinics and visits. There is no perfect or gold standard clinical measure of optic nerve function, and the clinician must rely upon different combinations of these tools in individual patients to reliably detec meaning visual change

The Neurobiology of Non-Organic DisordersfMRI/PET/SPECT

Functional disorders are common in clinical practice; indeed, it has been estimated that 20% of outpatient neurologic encounters harbor unexplained medical symptoms. Such disorders are also common in ophthalmology clinics, where 1-5% of patients manifest medically unexplained visual loss, and such impairments run a chronic course in up to 50% of patients. Accordingly, neuro-ophthalmology is often the crossroads for functional disorders within these specialties. Despite their frequency, these disorders are poorly understood

Walsh & Hoyt: Genetic Human Prion Disease

Approximately 1015% of human prion diseases are genetic or inherited, and associated with an identifiable defect in the PRNP gene, for an overall incidence of 1 in 10 million. This figure may grow with increasing genetic knowledge and the greater recognition of disease in individuals with a negative family history. In one survey of 57 patients with CJD, six of the nine patients with PrP gene mutations reported a negative family history. Penetrance of the autosomal-dominant prion diseases appears to be complete and age-dependent. The three main phenotypes that comprise the human familial prion diseases are familial CJD (fCJD), Gerstmann-Straussler-Scheinker (GSS) disease, and fatal familial insomnia (FFI)