In this work, we report the manifestations of carrier-dopant exchange interactions in colloidal Mn(2+)-doped CdSe/CdS core/multishell quantum wells. The carrier-magnetic ion exchange interaction effects are tunable through wave function engineering. In our quantum well heterostructures, manganese was incorporated by growing a Cd0.985Mn0.015S monolayer shell on undoped CdSe nanoplatelets using the colloidal atomic layer deposition technique. Unlike previously synthesized Mn(2+)-doped colloidal nanostructures, the location of the Mn ions was controlled with atomic layer precision in our heterostructures. This is realized by controlling the spatial overlap between the carrier wave functions with the manganese ions by adjusting the location, composition, and number of the CdSe, Cd1-xMnxS, and CdS layers. The photoluminescence quantum yield of our magnetic heterostructures was found to be as high as 20% at room temperature with a narrow photoluminescence bandwidth of ∼22 nm. Our colloidal quantum wells, which exhibit magneto-optical properties analogous to those of epitaxially grown quantum wells, offer new opportunities for solution-processed spin-based semiconductor devices.

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The Cooper Ornithological Society is pleased to present the report of the Advisory Panel on the Spotted Owl to the ornithological community. This panel was asked to judge the present status and future probabilities of this owl' s populations with increasing harvesting of old-growth forests in California, Oregon, and Washington. Further, the panel was to suggest research priorities to consolidate the information base on which timber management considerations will be made. The importance of this issue is manifest in the report. Very probably fewer than 6000 of the two races Strix occidentalis occidentalis and S.O. caurina remain in Washington, Oregon, and California from Kern County northward, with an estimated 2000 breeding pairs in that area. The Mexican Spotted Owl (S.O. fucida) is even rarer. Some observers suggest that the owl is so closely tied to old-growth forests in the northern portion of its range that any further harvesting of these forests would reduce the species in proportion to the area harvested. Many millions of dollars of timber and related jobs hinge on the outcome of decisions made on harvesting of old-growth timber. Thus the biology of this owl is a sensitive issue, but one which deserves a complete and impartial hearing. I feel strongly that the issue received such a hearing from the panel. A panel of experts was first suggested by the National Audubon Society which contacted the Cooper Society in mid-1985. To make the effort as broadly based as possible, the Society conferred with the President of the American Ornithologists' Union, Dr. Frances James. With Dr. James, we jointly appointed the panel and recommended to the Audubon Society that Dr. William R. Dawson be appointed chair. After his appointment, Dr. Dawson organized the panel, took testimony in the Pacific states, and carefully brought together the final product which you have below. The Audubon Society published a limited number of copies of the report (Audubon Conservation Rep. no. 7, 1986) but it is of such importance to the scientific community, and its history has been tied so directly to the Cooper Society, that we believe it is appropriate to publish it in The Condor. As you will see, the report is extremely comprehensive and a model to all those who attempt such a task in the future. We have not included the appendices, which included a glossary, documents provided to the panel, the panel' s agenda, and estimated costs of future research, as we felt that these were unnecessary to the scientific community' s understanding of the problem. The costs of the panel and of the publishing in The Condor were met by a private, anonymous donor. We are very grateful to this donor, and to each of the scientific panel members for their long hours of work, dedication to an excellent product, and their fairness in reaching their conclusions. Ornithology, and the Spotted Owl, will long be in their debt. C. John Ralph President State. First in response to recommendations of ture reversed the Chief of the Forest Service' s the Interagency Oreg...

The purpose of this study is to determine if frequent reflux events from an incompetent LES or poor clearance from decreased peristalsis is the predominant abnormality in PSS patients with severe reflux esophagitis. Seven patients with both classic manometric findings of PSS and endoscopic findings of esophageal ulcerations and/or Barrett's esophagus were compared to nine patients with similar endoscopic findings but with no evidence of a connective tissue disorder. All patients underwent simultaneous intraesophageal pH monitoring and scintigraphy for a total of 40 min after a radiolabeled meal. Four of the PSS patients and all the non-PSS patients had simultaneous manometry. We found that PSS patients had significantly fewer reflux events (P less than 0.01), but the reflux events had significantly longer duration (P less than 0.01) compared to patients with similar severity of esophagitis and no connective tissue disease. We conclude that decreased smooth muscle peristalsis appears to be the primary contributor to acid exposure and esophageal injury in PSS.

We used photoluminescence spectroscopy to resolve two emission features in CdSe/CdMnS/CdS and CdSe/CdS core/multi-shell nanoplatelet heterostructures. The photoluminescence from the magnetic sample has a positive circular polarization with a maximum centered at the position of the lower energy feature. The higher energy feature has a corresponding signature in the absorption spectrum; this is not the case for the low-energy feature. We have also studied the temporal evolution of these features using a pulsed-excitation/time-resolved photoluminescence technique to investigate their corresponding recombination channels. A model was used to analyze the temporal dynamics of the photoluminescence which yielded two distinct timescales associated with these recombination channels. The above results indicate that the low-energy feature is associated with recombination of electrons with holes localized at the core/shell interfaces; the high-energy feature, on the other hand, is excitonic in nature with the holes confined within the CdSe cores.