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The homogeneity of the magnetic field of an Oxford 85/310HR magnet was optimized with the use of passive shims (i.e., pieces of steel) and room-temperature electronic shims. Both the characteristics of the passive shims and the current settings for the room-temperature electronic shims were calculated with the goal of minimizing field inhomogeneities as assessed by Fourier analysis of data from circular field plots. The measurement techniques, the methods of data analysis, and the techniques employed in correcting the magnetic field are presented. Difficulties and constructive approaches are suggested in these descriptions. The final results show a field of excellent homogeneity over a 10-cm-diameter spherical volume, with a peak-to-peak variation of 3.2 ppm, which is better than the manufacturer's expected specification of 5 ppm. A water-filled sphere of 10 cm diameter gave a half-height linewidth of 0.14 ppm after a small amount of additional touch-up shimming. The field homogeneity as corrected is much improved over its original state, allowing the acquisition of improved spectra from samples of a size several centimeters in each linear dimension. Thus the field homogeneity is more useful for in vivo spectroscopy, the purpose for which the magnet was intended. © 1988 Academic Press, Inc.

The effects of distraction on the contingent negative variation (CNV) were investigated in a group of 11 elderly (mean = 72.2 years) and a group of 12 young (mean = 23.3 years) subjects. Scalp electrical activity was recorded from midline sites at frontal, central, and parietal locations. Three experimental conditions included Recall, No Recall, and Control situations. In the Recall, or distraction condition, spoken consonant-vowel-consonant (CVC) letters were presented concurrently with the CNV signal interval and were recalled by the subjects after each trial. The No Recall condition was similar to the Recall task except that subjects were not required to repeat the CVSs. The Control condition presented a standard S1 - S2 CNV situation without CVCs. Amplitudes of the CNV, reaction times (RTs), and heart rate (HR) served as indices of distraction. The effects of distraction for both age groups indicated reduced CNVs, lengthened RTs, and elevated HRs. However, a significant age by electrode interaction revealed that while CNV amplitudes at central and parietal sites were comparable between age groups, amplitudes at the frontal placement were consistently reduced in the elderly compared to the young in all conditions. The finding of diminished frontal activity, as measured by the CNV, suggests a process of selective cortical aging and possible cellular loss which may be linked to performance deficits.

Reports the occurrence of these two brackish-water copepods in the freshwater layer of Tuborg Lake, at the head of Antoinette Bay, one of the eastern extensions of the Nansen Sound-Greely Fiord system. Drepanopus bungei has been known previously only from the arctic coast of Siberia; it was also found in Disraeli Fiord on the north coast of Ellesmere Island. Tuborg Lake has been cut off from the Arctic Ocean for 3000 yr, hence these species are relict from a time when they were more widespread in the Arctic, probably owing to a generally lower salinity. The Tuborg Lake population of Limnocalanus macrurus grimaldii fits into Linquist's "non-extreme grimaldii" category has evolved only slightly, if at all, toward the macrurus form (with highly vaulted forehead). Remarks on the meromict layering and temperature/salinity profiles of the lake are included.

The Biology of Mysids and Euphausiids. Advances in Marine Biology, 18. By J. Mauchline. Pp.677. ISBN 0-12-026118-9. (Academic: 1981.) £38.60, $89.

Eurytemoraaffinis is reported from the Ohio River at Louisville, Kentucky, about 2,960 river miles upstream from the Gulf of Mexico. This is about 2,254 river miles beyond the farthest penetration up the Mississippi River previously known: Horn Lake, De Soto County, Mississippi.

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Anilocra acuta (Isopoda: Cymothoidae), previously known from Georgia and from Tampa Bay, Florida, is recorded from the lower Ochlockenee River and from Alligator Harbor, Florida, from Louisiana, and from the lower Hudson River, New York. New hosts areLepisosteus spatula, Bairdiella chrysura, andExox niger.

Evidence is presented for the recent introduction of Cirolana arcuata, previously known from Australia and New Zealand, into San Francisco Bay, where it appears to be established. Thus far it has been found only at the Oleum Power Plant on San Pablo Bay near Rodeo. C. robusta Menzies, from Chile, and Chilean specimens identified as C. concinna by Menzies are shown to belong to C. arcuata. The species is redescribed and illustrated in detail.

During a 7-year study of greater prairie chickens (Tympanuchus cupido pinnatus) in Kansas, 24 juveniles were captured, banded, and fitted with radio transmitters. Their monthly ranges and day-today movements showed that they moved more than adults during late autumn and during the spring booming season. They also suffered heavier morta ity than adults, especially during the fall dispersal. Broods broke up before dispersing, and both activities occurred in late August through September. Mortality was about 56 percent for broods under 10 weeks of age, and less thereafter. J. WILDL. MANAGE. 41(1):27-34 Although biologists investigated brood activities of some grouse species in North America, few data are available for greater prairie chickens. Earlier studies of prairie chickens in Kansas (Robel et al. 1970) detected extensive movements of juveniles in October and November. If the increased movements represented dispersal, and the observed high mortality of these dispersing juveniles was representative of all juveniles, then dispersal and resulting mortality might be a force regulating the population. The primary objective of this study was to gather additional information on mobility, mortality, brood break-up, and dispersal of juvenile greater prairie chickens. We wish to acknowledge the cooperation of J. Simpson, owner of the land on which this study was conducted, and the field assistance of J. Tatschl, A. Bisset, and D. Bowen. MATERIALS AND METHODS The study was done in Geary and Waubaunsee counties, 20 to 30 km southsoutheast of Manhattan, Kansas, in 1964-70. The area is typical of the western edge of Kansas Flint Hills bluestem prairie, which extends from Nebraska southward to Oklahoma. The topography and vegetation of the study area were described by Robel et al. (1970). Year-round grazing by cows with calves was light to moderate with some season-long grazing by steers and rotation of pasture use. Some of the pastureland was mowed annually for prairie hay. Juvenile prairie chickens were livetrapped on booming grounds in spring and fall with cannon nets (Silvy and Robel 1967) and throughout the year with funnel-type, walkin traps of various sizes (Watt 1969:34). All caught were banded, and some were equipped with miniature radio transmitters (Marshall and Kupa 1963, Brander 1968) and released. Their subsequent movements were monitored with portable receivers. When a bird with a transmitter moved beyond the range of ground-based portable receivers (0.8 to 1.5 km), portable receivers in a Cessna 120 aircraft were used. At an altitude of 300 m, signals could be received from 13 km. When a bird could not be located after 2 days of ground and aerial searches, its transmitter was assumed to have stopped working. Attempts were made to locate each transmitter-equipped prairie chicken two or three 1 Contribution No. 1266, Division of Biology, Kansas Agricultural Experiment Station, Kansas State University, Manhattan 66506. The study was financed by the National Institutes of Health, the National Science Foundation, and the Kansas Agricultural Experiment Station. 2 Present address: Bays Mountain Park, RR #4, Kingsport, Tennessee 37660. J. Wildl. Manage. 41(1):1977 27 This content downloaded from 207.46.13.51 on Tue, 21 Jun 2016 06:08:45 UTC All use subject to http://about.jstor.org/terms 28 DISPERSAL OF YOUNG PRAIRIE CHICKENS " Bowman and Robel times a day at different times each day to determine daily and seasonal movements. Occasional continuous monitoring for 10to 24-hour periods supplemented the data on daily movements. Radio-determined locations were plotted on base maps and the outermost points connected to determine monthly ranges for each bird (Mohr 1947). The distances between successive daily locations gave an index of mobility. On any day when two or more locations were recorded for an individual bird, we chose one of them at random to represent that day. Ranges and distances for each juvenile were calculated for each month, movements from the last day of one month to first of the next being recorded in the earlier month. Standard errors were calculated (Snedecor and Cochran 1967:50) for both ranges and distance for each month class. The distance between capture site and the last location was the "effective distance of dispersal" (Johnston 1961).

Oithona colcarva, n. sp., is described and compared with related species. It is common in coastal and estuarine waters of the Gulf of Mexico and the Atlantic coast south of Cape Cod. Since 1925 it has been incorrectly known asOithona brevicornis. *** DIRECT SUPPORT *** A00BY058 00006

The no‐slip boundary condition results in a leading edge acceleration dependent on velocity distribution across the sheet, but not directly on viscosity. For a one‐seventh power distribution, the acceleration of the leading edge must be in the range 0.765‐0.875 g.

Chesapeake Bay specimens ofAcartia, identified by C. B. Wilson asA. clausii andA. longiremis, were re-examined. All the specimens identified asA. longiremis and most of those labelledA. clausii wereA. tonsa. A. clausii was present only in two winter samples. The postulated change in the composition of species ofAcartia in the Bay can no longer be supported, since it arose from Wilson's misidentifications.

Ein neuer cirolanider Isopode, Excirolana kumari, wird beschrieben. Er bewohnt Rohren in einem Mangrovehabitat bei Port Swettenham in Malaysia. Der Sexualdimorphismus ist ausgepragt; das Mannchen besitzt auffallige "Horner" am Kopf und den ersten beiden Pereoniten sowie eine sehr viel starker entwickelte zweite Antenne als das Weibchen. Die Jungtiere werden im Korper erbrutet.

Two living specimens ofHyperia galba were observed to hold on and move in an inverted position while attached to the scyphozoan medusa,Cyanea capillata. The mouthparts face away from the substrate and ifH. galba is parasitic, it probably feeds on the tentacles or oral arms rather than the bell of the jellyfish. During the collection of hydrographic data in Narragansett Bay, members of three hyperiid species were found to occur on the jellyfishes,C. capillata, Aurelia aurita, andTima formosa. While making similar collections in the Niantic River, two amphipod species were observed onC. capillata. Two hyperiids are reported from Patuxent River and Chesapeake Bay representing range extensions for both.