Everyday infant experiences among the Aka hunter-gatherers and the neighboring Ngandu farmers were observed and compared. Twenty Aka and 21 Ngandu 3- to 4-month-olds and 20 Aka and 20 Ngandu 9- to 10-month-olds were observed for 3 hr on each of 4 days so that all 12 daylight hr were covered. The Aka infants were more likely to be held, fed, and asleep or drowsy, whereas Ngandu infants were more likely to be alone and to fuss or cry, smile, vocalize, or play. The amount of crying, soothing, feeding, and sleeping declined over time in both groups. Distal social interaction increased over time among the Ngandu but not among the Aka. Despite striking cultural differences on many variables, however, functional context systematically affected the relative prominence of the infants' behavior in both cultural groups.
Inter-Rydberg transitions of Ar2 in the green (∼460–530 nm) have been studied by intracavity, laser absorption spectroscopy. All five Hund’s case (c) members of the Aπu5p manifold, predicted by the guidelines established by Mulliken [J. Chem. Phys. 52, 5170 (1970)] for Xe2 and later adapted by Chang and Setser [J. Chem. Phys. 69, 3885 (1978)] for Ar2, have been observed. The molecular transitions originate from Aσg4s(1u,0−u) and terminate on the A2 Σ+ 1/2 u ion core, 3Πg on the A2 Σ+ 1/2 u ion co-derived (5p Rydberg electron 0−g, 0+g, 2g, 1g, and 1g. Transitions involving three of these are strongly red degraded [revealing that Re4s(1u, 0−u) <Re5p(0−g) ≲Re(0+g)<Re(1g upper)] whereas the bands associated with the 2g and lowest 1g levels are not. Analysis of newly observed hot bands (Δv≡v′−v″<0) yields the following vibrational constants for ω″e =297.2±1.0 cm−1, ω″e x″e =3.3±0.4 cm−1, and ω″e y″e =0.08±0.05 cm−1. Several clear vibrational sequences are observed and tentative assignments for the Aπu5p separated atom limits are reported. The 0−g, 0+g, (2g, 1g), and 1g (upper) states apparently correlate (in the separated atom limit) with Ar(1S0)+Ar 5p[ 1/2 ]1, [ (5)/(2) ]2, [ (5)/(2) ]3, and [ (3)/(2) ]1, respectively, which is consistent with the known 4p, 5p→4s oscillator strengths, the Ar 3p5 5p fine structure splittings, and the measured energy defects between the Aπu5p substrates. Rather than being degenerate at small R, the 0−g and 0+g states of the πu5p manifold are split by 247 cm−1 near Re. Bandheads arising from the Aσu5p(0−g)←Aσg4s (1u, 0−u) transition have also been observed. Calculations show that the Aσu5p(0−g) state dissociation energy (D0≂1.0 eV) is noticeably smaller than that for the Aπu5p levels (D0=1.26±0.01 eV).
Extensive spectra attributable to transitions from the 4sO" a 3~ + metastable state of Ar 2 to excited Rydberg states have been observed by intracavity absorption spectroscopy and by laser excitation spectroscopy in the afterglow of a pulsed corona discharge. Of these the most extensive and best resolved were the laser induced fluorescence spectra. Most of the spectra can be assigned to vibronic transitions in the nf:i eITg,3~t) and np:i eITg/~g+).-a 3~u+ series. The 5P1T 3IT g .-a 3~u+ and 7pO" 3~g+ .-a 3~: transitions observed near 19 823 and 19 529 cm -I, respectively, exhibit many bands with v' =f 0 in their (v' -v") vibrational band system developments. The higher n value members of these and other observed series are dominated by (0--0) transitions. Rotational structure is partially resolved in a few bands of the 7pO" 3~g+ -a system, but most of the spectra observed appear to be either rotationally unresolved or made up of blended collections of rotational lines. Above the 7pO", 5P1T pair, the (n + 2)pO" 3~g+ and np1T 3ITg members of the np:i series rapidly c9,alesce, indicating a rapid onset of decoupling of the electronic orbital angular momentum, L, from the internuclear axis. Such decoupling leads to np-complex formation at n values much lower than observed in the np:i series of the lighter dimers: He 2 and Ne2' From the data for the observed series, the lowest ionization limit of Ar2 (relative to a 3~u+ ,v = 0) was determined to be 29 373 ± 3 cm -I.Vibrational intervals 6.G(v + 112) for a 3~u+ (v<4) and 7pO" 3~g+ (v<2) yield the vibrational constants {J)e = 296 and 282 cm -I and x{J)e = 2.5 and 17 cm -I, respectively.
Spectra attributed to transitions from the 5sσ a 3Σu+ metastable state of Kr2 to excited Rydberg states have been observed by intracavity and multipass absorption and by laser excitation spectroscopy. Four distinct Rydberg series converging on the X 2Σu+ core of Kr2+ have been identified. Rotational structure is not resolved in any of the observed spectra. Most of the spectra can be assigned to vibronic transitions in the nfλ(3Πg,3Σg+) and npλ(3Πg,3Σg+)←a 3Σu+ series by analogy with similar spectra in the lighter rare gas dimers. The 6pπ 3Πg←a 3Σu+ and 8pσ 3Σg+←a 3Σu+ transitions observed in the ∼19 200–18 200 cm−1 region exhibit many bands with v′≠0 in their (v′–v″) vibrational band system developments. The higher n value members of these and other observed series are dominated by (0–0) transitions. All series are perturbed in a few energy regions by states built on the excited ion core states A 2Π3/2g and B 2Π3/2u. Laser excitation spectra for the 8pσ 3Σg+←a transition obtained by monitoring various 5p→5s emission lines of atomic krypton suggest that the 8pσ 3Σg+ Rydberg state of Kr2 is predissociated by a repulsive potential correlated with Kr 5p[3/2]1+Kr(1S0). The lowest ionization limit of Kr2 (relative to a 3Σu+,v=0) was determined to be 28 484±5 cm−1.
Subsequent analyses using Tukey honestly significant difference tests revealed no group differences in adult vocalizations to infants at 3 months, although the Ngandu adults vocalized more than the Aka adults at 9 months (p < .039) and engaged in more mutual visual interactions at 9 months (p < .02) but not at 3 months; in contrast, en-face interactions increased over time among the Aka (p < .003) but not among the Ngandu.
The emission spectrum of Br2 in the ultraviolet (180≤λ≤400nm) has been examined in electron beam pumped rare gas–hydrogen bromide (HBr) gas mixtures. Temporally resolved and rare gas pressure-dependent studies of the Br2 fluorescence at 292 (D′→A′), 312, 334, and 358 nm indicate that the formation processes for Br2 ion pair states differ for Ne and Ar diluents. Experimental evidence suggests that Br2 excited states in the first tier [correlated with Br−(1S0)+Br+(3P2)] in Ar/HBr mixtures are formed by ion–ion recombination in which Br+(3P2) is produced by charge transfer between Ar+(2P) and HBr, followed by predissociation of HBr+(A 2Σ+). In Ne buffer, Br2 states well above D′ are apparently produced by Penning ionization of HBr by Ne 3s 3P followed by recombination of Br+(3P0,1,2 ) ions with Br−(1S0). Also, Ar is effective in collisionally relaxing the lowest manifold of six Br2 ion pair states but both Ne and Ar are poor quenchers of the D′(2g) level.
The Digit S an subtest from the Wechsler Intelligence Scale for Children was administerex to 48 children. Half of the children were administered the test under the Wechsler procedures (last digit dropped in inflection), and the other half were administered the test under the Stanford-Binet procedures (uniform emphasis on all digits). Ss under the Wechsler procedure repeated significantly more digits in both the forward and backward conditions than did Ss under the Stanford-Binet procedures. It is suggested that for maximal use of normative data, examiners should be careful to administer these tests by the procedures under which they were standardized.
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