Enhanced glacial discharge from the eastern Antarctic Peninsula since the 1700s associated with a positive Southern Annular Mode.

The Antarctic Peninsula Ice Sheet is currently experiencing sustained and accelerating loss of ice. Determining when these changes were initiated and identifying the main drivers is hampered by the short instrumental record (1992 to present). Here we present a 6,250 year record of glacial discharge based on the oxygen isotope composition of diatoms (δ18Odiatom) from a marine core located at the north-eastern tip of the Antarctic Peninsula. We find that glacial discharge - sourced primarily from ice shelf and iceberg melting along the eastern Antarctic Peninsula - remained largely stable between ~6,250 to 1,620 cal. yr BP, with a slight increase in variability until ~720 cal. yr. BP. An increasing trend in glacial discharge occurs after 550 cal. yr BP (A.D. 1400), reaching levels unprecedented during the past 6,250 years after 244 cal. yr BP (A.D. 1706). A marked acceleration in the rate of glacial discharge is also observed in the early part of twentieth century (after A.D. 1912). Enhanced glacial discharge, particularly after the 1700s is linked to a positive Southern Annular Mode (SAM). We argue that a positive SAM drove stronger westerly winds, atmospheric warming and surface ablation on the eastern Antarctic Peninsula whilst simultaneously entraining more warm water into the Weddell Gyre, potentially increasing melting on the undersides of ice shelves. A possible implication of our data is that ice shelves in this region have been thinning for at least ~300 years, potentially predisposing them to collapse under intensified anthropogenic warming.

Heritability estimates versus large environmental effects: the IQ paradox resolved.

Some argue that the high heritability of IQ renders purely environmental explanations for large IQ differences between groups implausible. Yet, large environmentally induced IQ gains between generations suggest an important role for environment in shaping IQ. The authors present a formal model of the process determining IQ in which people's IQs are affected by both environment and genes, but in which their environments are matched to their IQs. The authors show how such a model allows very large effects for environment, even incorporating the highest estimates of heritability. Besides resolving the paradox, the authors show that the model can account for a number of other phenomena, some of which are anomalous when viewed from the standard perspective.

Treatment of early vocal cord carcinoma: a comparison of apples and apples.

Radiation therapy, hemilaryngectomy, and even cordectomy will cure a very large percentage of patients with early vocal cord cancer and preserve the voice. However, hemilaryngectomy and cordectomy are conceded by most surgeons to usually produce a poorer voice, compared to radiation therapy, and the operations are restricted to certain anatomical distributions. Those surgeons advocating hemilaryngectomy or cordectomy have compared their results with radiation therapy series which include a proportion of patients with lesions not suitable for voice-sparing operations. One hundred and thirty-nine patients with T 1-2 carcinoma of the vocal cords with a 2-15 year follow-up, who were treated initially by radiation therapy, were analyzed in detail by initial extent of disease. Patients were identified whose lesions were anatomically suitable for hemilaryngectomy or cordectomy, and results for these patients compared to operative results. Since the curative results with voice sparing by irradiation were at least equal, and since the quality of the voice is thought to be much better, there is little justification for recommending a major operation except in specific situations. Lesions initially suitable for voice-sparing operations which subsequently recur after irradiation can usually be treated by a voice-sparing operation.

Chemodectomas arising in temporal bone structures.

Eighteen patients with chemodectomas arising in temporal bone structures were evaluated and treated at the University of Florida. Seventeen patients have each been followed a minimum of 3 years. Patients were retrospectively staged as having "local" or "advanced" disease, depending on the presence or absence of bone destruction and/or cranial nerve involvement. Fourteen of the patients received radiation therapy as all or part of their therapy; 6 patients were treated with radiation therapy alone, 3 patients were irradiated immediately postoperatively for residual disease, and 5 patients had radiation therapy for recurrence after operation. They were treated with cobalt-60 radiation with doses ranging from 3760 to 5640 rad. All irradiated patients demonstrated evidence of tumor regression, and none have had tumor recurrence with followup of 3-12 years. Of the 8 patients with cranial nerve paralysis prior to therapy, 5 had return of function of 1 or more cranial nerves. One of 6 patients treated initially with radiation therapy had a complication, while 6 of 8 patients irradiated postoperatively had complications. None of the complications were fatal. Three patients treated by operation for early disease limited to the hypotympanum had the disease controlled for 11-12 years. Guidelines for the selection of initial therapy are discussed.

Giant drusen (astrocytic hamartoma) of the optic nerve seen with computerized axial tomography.

An EMI scan (computerized axial tomography) performed on a 75-year-old man with giant drusen (astrocytic hamartoma) of the left optic nerve clearly revealed a dense localized mass at the distal termination of the left optic nerve. The EMI scan proved to be an accurate, noninvasive technique for neuro-ophthalmologic diagnosis.