This study examined relations between eye movements and accuracy scores in a delayed matching-to-sarnple procedure with multiple sample stimuli. Four adult humans responded with high accuracy when there were 2 samples per trial. When the number of samples was increased to 4 per trial, accuracy scores fell to intermediate levels for 2 of the subjects, and then recovered to high levels following practice. Eye-tracking analyses showed that subjects with high and low accuracy on the initial 4-sample trials made similar numbers of observations per trial , but high-accuracy subjects exhibited longer sample-stimulus observing durations. Practice and improvement to high accuracy was accompanied by relatively small changes in observing frequencies and large increases in sample-stimulus observing durations. The results are discussed in terms of independent stimulus control of different aspects of observing behavior topography. One topic of continuing interest in analyses of stimulus control concerns the range, breadth, or number of stimuli that can exert control simultaneously. This question has been addressod in such diverse areas as, for example, breadth of attention in animal cognition (e.g., Maki & Leuin, 1972); the effects of task complexity (number of stimuli) on reaction times in aging populations (e.g., Baron & Menich, 1985); and stimulus overselectivity, an atypically restricted breadth of stimulus control related to learning problems of some individuals with dHvelopmental disabilities Data collection and manuscript preparation were supported by NICHD Grants HD25995 and HD37055, and CNPq Grant 200552/96-1. The contents of this paper are solely the responsibility of the authors and do not necessarily represent the official views of NICHD. Some of the data were presented at the annual conference of the Southeastern Association for Behavior Analysis, Chapel Hill, NC, October, 1997. We thank Kevin Farren for assistance in data analysis, Bill Mcllvane for advice on the project, and Bill Mcllvane and Richard Serna for comments on the manuscript. For their generosity with technical support and assistance, we thank Rikki Razdan and

Students with mental retardation learned to write lists in order to perform a matching task that they could not do otherwise. After an initial assessment phase, reinforcement was arranged in the computerized tasks to follow selection of the six pictures that were identical to those in the six-picture samples presented. In Study 1, even though the participants wrote a list of the names of the six sample pictures on each trial, read a list, or did both, they often made errors when a brief delay preceded picture selection. In contrast, performance was nearly perfect when a list was written, read, and remained available at the time of picture selection, suggesting that the list served to mediate the delays. Study 2 examined the stimulus control by two- and six-picture samples over the list writing. Early during testing, 1 participant refrained from writing lists on two-picture trials but wrote lists on six-picture trials, thereby maximizing reinforcement and minimizing its delay; the other participant showed this pattern of list writing after supplemental training. The studies suggest methods for establishing a rudimentary repertoire of mediating behavior that has relevance for teaching instruction-following skills in natural settings.

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The ratio of the nuclear gi factor to the atomic gj factor in 86 Rb has been measured by the atomic-beam magnetic-resonance technique to be g/(uncorr)/gj-= -1. 466478 (22) X10~4. This result is in excellent agreement with recent optical-pumping measurements but is lower than a previously reported atomic-beam result. R ECENT optical-pumping determinations of gi/gj for free 85 Rb atoms 1 are in considerable disagreement with an earlier atomic-beam measurement of the same ratio. 2 Because the discrepancy between the optical-pumping and atomic-beam results is nine times the larger experimental uncertainty, the question immediately arises whether this discrepancy is indeed real, or whether one of the measurements is in error. If the discrepancy were real, this would have had interesting implications for atomic theory.In an attempt to resolve this question, we have remeasured the nuclear magnetic moment of 85 Rb, using the atomic-beam magnetic-resonance technique, and have obtained a result in agreement with the opticalpumping measurement. In an attempt to vary our technique from that used in Ref. 2, we have used the triple-loop method 3 in our measurements and have observed the CF=3, MF= -1) <-> (3, -2) transition at its field-independent point at 2076.44 G. The frequency of this line is strongly dependent upon the value of gr (dv/dgr= -2905, where v is in MHz and gi is referred to the Bohr magneton), but depends less on the other parameters (dv/da= 9.58, dv/dgj= -0.43) in the BreitRabi equation; thus this transition is well suited to a direct measurement of gi.A special triple hairpin, shown in Fig. 1, was constructed to observe this transition. The two end hairpins were constructed of standard rigid coaxial line and were used to induce the (3, •-2)<-> (3, -3) transition. In use, the magnetic field was shimmed as necessary to make the transition frequency the same in both hairpins. The center hairpin, which was used to induce the (3, -1) <-» (3, -2) transition, was of a simple box-type construction with a center conductor shorted at the bottom of the hairpin. The center hairpin had a length of 4.5 in., resulting in a resonance linewidth of 5 kHz for this transition. This type of hairpin has been used and tested quite extensively by our group, and has yielded reliable results for frequencies up to about 700 MHz. A typical 85 Rb (3, -1) <-> (3, -2) resonance observed with this hairpin is shown in Fig. 2. The magnetic field was calibrated by measuring the frequency of the (3, --2) <-> (3, -3) transition with the center hairpin.The center frequency of the resonance was determined by measuring the frequencies of three pairs of points symmetrically placed about the center of the resonance. These six points were taken at random heights varying from one-third to near full height for each resonance. We were careful to record each pair of symmetrically placed points as quickly as possible, to avoid errors introduced by random fluctuations of resonance height. The average of the three pairs was taken to be the center frequency...

Open wounds represent a potential area of medicolegal risk if foreign bodies are not identified prior to wound closure. The importance of imaging of lacerations was underscored by a recent case where a 20-year-old male collided with a friend's mouth on a trampoline sustaining a simple, superficial scalp laceration. The wound was evaluated in typical fashion including irrigation and local exploration and was prepared for closure. The friend was then evaluated and noted to have multiple extensive dental fractures. An increased index of suspicion generated further evaluation of the first patient's wound. Plain radiography obtained of the first patient's skull was noted to have bony foreign bodies consistent with teeth, which were then removed after further exploration. Superficial wounds are common and complications arising from retained foreign bodies are a potential source of substantial morbidity and consequently medical litigation. This case serves as a reminder to be vigilant and maintain a high index of suspicion regarding the potential for foreign body.

The asymmetric syntheses of a range of N- and O-protected 3-deoxy-3-aminosphingoid bases have been achieved using two complementary approaches. dl-Serine was converted to a racemic N,N-dibenzyl-protected γ-amino-α,β-unsaturated ester which was resolved using a parallel kinetic resolution (PKR) strategy upon reaction with a pseudoenantiomeric mixture of lithium (R)-N-benzyl-N-(α-methylbenzyl)amide and lithium (S)-N-3,4-dimethoxybenzyl-N-(α-methylbenzyl)amide, giving the corresponding enantio- and diastereoisomerically pure β,γ-diamino esters. Alternatively, elaboration of l-serine gave the corresponding enantiopure N,N-dibenzyl-protected γ-amino-α,β-unsaturated ester, and doubly diastereoselective conjugate addition of the antipodes of lithium N-benzyl-N-(α-methylbenzyl)amide was found to proceed under the dominant stereocontrol of the lithium amide reagent in both cases, thus augmenting the accessible range of β,γ-diamino esters. Both of these protocols were expanded to include in situ oxidation of the enolate formed upon conjugate addition, giving access to the corresponding α-hydroxy-β,γ-diamino esters. Elaboration of these β,γ-diamino and α-hydroxy-β,γ-diamino esters gave the protected forms of the 3-deoxy-3-aminosphingoid base targets.

Women experienced fewer injuries than men in postinvasion Baghdad, but were more likely to suffer disability after injury. Efforts to improve conditions for injured women should focus on mitigating financial and provisional hardships, providing counseling services, and ensuring access to rehabilitation services.