Ice retreat in Wilkes Basin of East Antarctica during a warm interglacial.

Efforts to improve sea level forecasting on a warming planet have focused on determining the temperature, sea level and extent of polar ice sheets during Earth's past interglacial warm periods1-3. About 400,000 years ago, during the interglacial period known as Marine Isotopic Stage 11 (MIS11), the global temperature was 1 to 2 degrees Celsius greater2 and sea level was 6 to 13 metres higher1,3. Sea level estimates in excess of about 10 metres, however, have been discounted because these require a contribution from the East Antarctic Ice Sheet3, which has been argued to have remained stable for millions of years before and includes MIS114,5. Here we show how the evolution of 234U enrichment within the subglacial waters of East Antarctica recorded the ice sheet's response to MIS11 warming. Within the Wilkes Basin, subglacial chemical precipitates of opal and calcite record accumulation of 234U (the product of rock-water contact within an isolated subglacial reservoir) up to 20 times higher than that found in marine waters. The timescales of 234U enrichment place the inception of this reservoir at MIS11. Informed by the 234U cycling observed in the Laurentide Ice Sheet, where 234U accumulated during periods of ice stability6 and was flushed to global oceans in response to deglaciation7, we interpret our East Antarctic dataset to represent ice loss within the Wilkes Basin at MIS11. The 234U accumulation within the Wilkes Basin is also observed in the McMurdo Dry Valleys brines8-10, indicating11 that the brine originated beneath the adjacent East Antarctic Ice Sheet. The marine origin of brine salts10 and bacteria12 implies that MIS11 ice loss was coupled with marine flooding. Collectively, these data indicate that during one of the warmest Pleistocene interglacials, the ice sheet margin at the Wilkes Basin retreated to near the precipitate location, about 700 kilometres inland from the current position of the ice margin, which-assuming current ice volumes-would have contributed about 3 to 4 metres13 to global sea levels.

A targeted neuropsychological examination of children with a history of sport-related concussion.

Experimental research suggests that sport-related concussion can lead to persistent alterations in children's neurophysiology and cognition. However, the search for neuropsychological tests with a similar ability to detect long-term deficits continues. PRIMARY OBJECTIVE: The current study assessed whether a target battery of neuropsychological measures of higher cognition and academic achievement would detect lingering deficits in children 2 years after injury. RESEARCH DESIGN: Cross-sectional. METHODS AND PROCEDURE: A total of 32 pre-adolescent children (16 concussion history, 16 control) completed a targeted battery of neuropsychological and academic tests. MAIN OUTCOMES AND RESULTS: Children with a history of concussion exhibited selective deficits during the Raven's Coloured Progressive Matrices, Comprehensive Trail-Making Test, and the mathematics sub-section of the WRAT-3. Deficit magnitude was significantly related to age at injury, but not time since injury. CONCLUSIONS: The current results suggest that neuropsychological measures of higher cognition and academic achievement may be sensitive to lingering deficits, and that children injured earlier in life may exhibit worse neuropsychological and academic performance.

The Relationship between Total Water Intake and Cognitive Control among Prepubertal Children.

BACKGROUND: Cognitive control (also known as executive function) encompasses mental processes that underlie goal-directed behavior, and it enables us to adjust our behavior according to changing environmental demands. Previous research among children has demonstrated that aerobic fitness and obesity have contrasting and selective effects on cognitive control. However, the relationship between water intake and childhood cognitive control remains inadequately studied. This study investigated the relationship between total water intake and cognitive control among prepubertal children (8-9-year olds). METHODS: Children between 8 and 9 years of age (n = 63) performed a modified flanker task to assess cognitive control related to inhibition (ability to resist distractions and maintain focus). Diet was measured using 3-day food records. Total water was defined as water consumed from drinking water, beverages, and food. RESULTS: A comparison of task performance across the median intake of total water revealed that children above the median exhibited shorter reaction times across multiple conditions of the flanker task, requiring variable amounts of cognitive control. Further, after adjustment of age, IQ, socioeconomic status, weight status, and aerobic fitness level, the proportion of intake comprised of water (%TW) was negatively correlated with reaction time interference, that is, the ability to maintain task performance when task conditions demanded greater inhibition. CONCLUSIONS: These results indicate an association between water intake and cognitive control using a task that modulates inhibition. Specifically, higher water intake correlated with greater ability to maintain task performance when inhibitory demands are increased. Future work is needed to determine the mechanism by which water influences cognitive control among children.

Bis(tetraphenylphosphonium) tris(oxalato-O,O')germanate(IV).

The synthesis and structure of the title compound, (C(24)H(20)P)(2)[Ge(C(2)O(4))(3)], are reported. The PPh(4)(+) cations in the structure form infinite zigzag chains in which the P.P distances alternate between 6.229 (1) and 7.118 (1) A, and the P.P.P angle is 131.4 (1) A. The shorter P.P distance is associated with a sixfold phenyl embrace. However, the longer P.P distance is associated with both phenyl-phenyl interactions and interactions between the cations and a twofold symmetric [Ge(C(2)O(4))(3)](2-) anion. In the cation-anion interactions, the P.O distance is 4.444 (2) A, the O.P-C(distal) angle is 175.0 (1) degrees and the shortest H.O distances are 2.74 and 3.09 A.

Long term results of glaucoma surgery among participants in an east African population survey.

AIM: To evaluate the long term results of glaucoma surgery among people in East Africa. METHODS: Participants in a population based survey of eye disease prevalence were offered glaucoma surgery using standardised criteria. Either surgical iridectomy or trabeculectomy was carried out as indicated by a medical officer or by one of two ophthalmologists. Trabeculectomy methods included releasable sutures and mitomycin C in the majority of eyes. Subjects were examined during the first week and 2 months after surgery. Nearly 3 years later, re-examination was carried out in those who were still resident in the region. RESULTS: Among 46 people who were offered iridectomy, trabeculectomy, or combined cataract extraction/lens implant/trabeculectomy, 21 people underwent surgery (46%). Of the 21, 19 were re-examined at 3 years (90%), including 16/18 eyes after trabeculectomy. Among these, intraocular pressure (IOP) declined from 29.9 (SD 9.4) mm Hg to 14.7 (5.9) mm Hg, with 16 of 18 eyes (89%) achieving a reduction > 25%. Hypotony maculopathy, late bleb leak, and late endophthalmitis were not detected. Visually significant cataract developed in 5/15 re-examined eyes that underwent trabeculectomy alone (33%), possibly associated with pre-existing cataract and diagnosis of angle closure glaucoma, but not with mitomycin C use. CONCLUSIONS: Nearly half of those with glaucoma among residents of rural African villages accepted the offer of surgical therapy. While technical success was achieved at satisfactory levels, the development of cataract must be considered an important issue for application of glaucoma surgical therapy programmes.

Crystal supramolecular motifs: columns of embracing Ph3PMe+ or Ph3PCI+ cations controlling formation of.

The crystal structures of (Ph3PCl)2[Cu3Cl8] (1) (triclinic, space group P1, a = 9.480(6) A, b = 10.243(8) A, c = 11.232(6) A, alpha = 86.76(4) degrees, beta = 66.62(5) degrees, gamma = 83.92(4) degrees, Z = 1) and (Ph3PMe)2[Cu3Br8] (2) (triclinic, space group P1, a = 9.795(4) A, b = 10.472(4) A, c = 11.392(4) A, alpha = 86.67(3) degrees, beta = 66.67(3)degrees, gamma = 83.14(3) degrees, Z = 1), reported here, demonstrate a new supramolecular motif for cations of the type Ph3PY+ where Y is CH3 or Cl. The crystals contain columns of cations propagated by alternating 6-fold phenyl embraces (6PE) and pseudo-6PE: the pseudo-6PE described here contains four phenyl rings and two hetero groups (Cl or CH3), and is symbolized as 4P2Y. The zigzag sequence of cations engaged in ...6P...4P2Y...6P...4P2Y... is similar to the zigzag chain of infinite 6-fold phenyl embraces (ZZI6PE) frequently adopted by Ph4P+ cations in crystals. One-dimensionally nonmolecular anion chains with repeat unit [Cu3X8] run parallel to and between the columns of cations. The coordination geometry in the [Cu3X8(2-)]1 to infinity chain has not been observed in crystals with other cations, and it is postulated that the attractive interactions between cations in the pseudo-ZZI6PE crystal supramolecular motif control the geometry of the anions through the requirement for commensurability of cation columns and anion chains.

CAD modeling of the birth process. Part II.

We are engaged in studying the process of human birth by developing a computer-based dynamic model that can be adapted to specific birth scenarios. The individual characteristics of a given pregnant woman and fetus, embedded in their clinical measurements and CT and MRI images, are captured in the model. One can thereby predict adverse events that might happen during labor and delivery. Based on our findings from a preliminary design and execution of this model, we believe it holds great promise as an accurate, cost-effective diagnostic and teaching tool that will help predict conditions during individual labor scenarios that might cause traumatic birth injuries, and thereby enable us to make the most informed clinical decisions possible.

Development and hormone regulation of androgen receptor levels in the sexually dimorphic larynx of Xenopus laevis.

Development of the sexually dimorphic larynx in African clawed frogs is controlled by secretion of androgenic steroids (D. Sassoon and D. Kelley, 1986, Amer. J. Anat. 177, 457-472). Adult laryngeal muscle shows high levels of androgen binding relative to other skeletal muscles and binding activity in males is three times that in females (N. Segil, L. Silverman, and D. Kelley, 1987, Gen. Comp. Endocrinol. 66, 95-101). To determine when androgen sensitivity and sex differences arise, we assayed [3H]dihydrotestosterone (DHT) binding activity in larynges from metamorphic and postmetamorphic male and female frogs. Scatchard analyses indicate that DHT binds to a saturable component with high affinity. At metamorphosis, male and female juveniles have average binding levels of 262 and 269 fmoles/mg protein, respectively, approximately 7 to 20 times their adult values. At 3 months postmetamorphosis (PM), sexually dimorphic binding levels are observed. Binding activity declines gradually in females from metamorphosis to 9 months PM. In males, levels of binding activity remain high throughout the first 6 months PM and then decrease to near adult levels by 9 months PM. Administration of exogenous DHT to 3 months PM juveniles decreases average binding activity from 180 (male) or 74 fmoles/mg (female) to 33.5 fmoles/mg in both sexes. Testosterone has a less pronounced effect on binding activity in males than DHT and is ineffective in females. We conclude that sexually dimorphic adult levels of androgen binding in larynx arise by differential decrease from initially high, sexually monomorphic levels and that high titers of circulating androgens normally present by 6 months PM in males are responsible for the marked decrease in binding activity observed during laryngeal development.

Spontaneous surface wrinkling retinopathy.

Spontaneously occurring surface wrinkling retinopathy occurreed in 17 eyes of 16 patients and was not related to pervious surgery, retinal vascular disease, or obvious ocular inflammation. Visual symptoms were not severe and follow-up suggests that the usual course of surface wrinkling is usually benign. However, 2 eyes progressed to 20/300, so that there is a chance of considerable visual deterioration in some cases. The vitreous may or may not be detached. The ophthalmoscopic features of a wrinkled shagreen, tortuous vessels pulled toward a nidus, and intraretinal hemorrhages were seen. The leakage of fluorescein into the retina is emphasized in this series and may be fairly marked. The possible causes and mechanism of wrinkling are discussed with emphasis on mild chronic ischemia and posterior vitreous collapse.