Compact Modeling of Parasitic Internal Fringe Capacitance Effects on the Threshold Voltage of High-K Gate Dielectric Nanoscale SOI MOSFETs

A compact model for the effect of parasitic internal fringe capacitance on threshold voltage in high-K gate dielectric SOI MOSFETs is developed. Our model includes the effects of the gate dielectric permittivity, spacer oxide permittivity, spacer width, gate length and width of MOS structure. A simple expression for parasitic internal fringe capacitance from the bottom edge of the gate electrode is obtained and the charges induced in the source and drain regions due to this capacitance are considered. We demonstrate an increase in surface potential along the channel due to these charges resulting in a decrease in the threshold voltage with increase in gate dielectric permittivity. The accuracy of the results obtained using our analytical model is verified using 2-D device simulations.Comment: Journal Pape

Enhanced Two-Photon Absorption in a Hollow-Core Photonic Bandgap Fiber

We show that two-photon absorption (TPA) in Rubidium atoms can be greatly enhanced by the use of a hollow-core photonic bandgap fiber. We investigate off-resonant, degenerate Doppler-free TPA on the 5S1/2 - 5D5/2 transition and observe 1% absorption of a pump beam with a total power of only 1 mW in the fiber. These results are verified by measuring the amount of emitted blue fluorescence and are consistent with the theoretical predictions which indicate that transit time effects play an important role in determining the two-photon absorption cross-section in a confined geometry.Comment: 5 pages, 6 figure

Tree Climbing and Human Evolution

Paleoanthropologists have long argued—often contentiously—about the climbing abilities of early hominins and whether a foot adapted to terrestrial bipedalism constrained regular access to trees. However, some modern humans climb tall trees routinely in pursuit of honey, fruit, and game, often without the aid of tools or support systems. Mortality and morbidity associated with facultative arboreality is expected to favor behaviors and anatomies that facilitate safe and efficient climbing. Here we show that Twa hunter–gatherers use extraordinary ankle dorsiflexion (\u3e45°) during climbing, similar to the degree observed in wild chimpanzees. Although we did not detect a skeletal signature of dorsiflexion in museum specimens of climbing hunter–gatherers from the Ituri forest, we did find that climbing by the Twa is associated with longer fibers in the gastrocnemius muscle relative to those of neighboring, nonclimbing agriculturalists. This result suggests that a more excursive calf muscle facilitates climbing with a bipedally adapted ankle and foot by positioning the climber closer to the tree, and it might be among the mechanisms that allow hunter–gatherers to access the canopy safely. Given that we did not find a skeletal correlate for this observed behavior, our results imply that derived aspects of the hominin ankle associated with bipedalism remain compatible with vertical climbing and arboreal resource acquisition. Our findings challenge the persistent arboreal–terrestrial dichotomy that has informed behavioral reconstructions of fossil hominins and highlight the value of using modern humans as models for inferring the limits of hominin arboreality

A Randomized Controlled Trial of Glucose versus Amylase Resistant Starch Hypo-Osmolar Oral Rehydration Solution for Adult Acute Dehydrating Diarrhea

Background: Reduction of gross diarrhea rate in excess of that seen over time with intravenous therapy and appropriate antibiotics is not usually achieved by oral glucose-electrolyte rehydration therapy for cholera and cholera-like diarrheas. Methodology and Principal Findings: This prospective randomized clinical trial at a tertiary referral hospital in southern India was undertaken to determine whether amylase resistant starch, substituting for glucose in hypo-osmolar oral rehydration solution, would reduce diarrhea duration and weight in adults with acute severe dehydrating diarrhea. 50 adult males with severe watery diarrhea of less than three days' duration and moderate to severe dehydration were randomized to receive hypo-osmolar ORS (HO-ORS) or HO-ORS in which amylase resistant high amylose maize starch 50g/L substituted for glucose (HAMS-ORS). All remaining therapy followed standard protocol. Duration of diarrhea (ORS commencement to first formed stool) in hours was significantly shorter with HAMS-ORS (median 19, IQR 10-28) compared to HO-ORS (median 42, IQR 24-50) (Bonferroni adjusted P, P-adj < 0.001). Survival analysis (Kaplan-Meier) showed faster recovery from diarrhea in the HAMS-ORS group (P < 0.001, log rank test). Total diarrhea fecal weight in grams (median, IQR) was not significantly lower in the HAMS-ORS group (2190, 1160-5635) compared to HO-ORS (5210, 2095-12190) (P-adj = 0.08). However, stool weight at 13-24 hours (280, 0-965 vs. 1360, 405-2985) and 25-48 hours (0, 0-360 vs. 1080, 55-3485) were significantly lower in HAMS-ORS compared to HO-ORS group (Padj = 0.048 and P = 0.012, respectively). ORS intake after first 24 hours was lower in the HAMS-ORS group. Subgroup analysis of patients with culture isolates of Vibrio cholerae indicated similar significant differences between the treatment groups. Conclusions: Compared to HO-ORS, HAMS-ORS reduced diarrhea duration by 55% and significantly reduced fecal weight after the first 12 hours of ORS therapy in adults with cholera-like diarrhea

Phenotypic Plasticity of Climbing-Related Traits in the Ankle Joint of Great Apes and Rainforest Hunter-Gatherers

The negrito and African pygmy phenotypes are predominately exhibited by hunter-gatherers living in rainforest habitats. Foraging within such habitats is associated with a unique set of locomotor behaviors, most notably habitual vertical climbing during the pursuit of honey, fruit, and game. When performed frequently, this behavior is expected to correlate with developmentally plastic skeletal morphologies that respond to mechanical loading. Using six measurements in the distal tibia and talus that discriminate nonhuman primates by vertical climbing frequency, we tested the prediction that intraspecific variation in this behavior is reflected in the morphology of the ankle joint of habitually climbing human populations. First, to explore the plasticity of climbing-linked morphologies, we made comparisons between chimpanzees, gorillas, and orangutans from wild and captive settings. The analysis revealed significant differences in two climbing-linked traits (anterior expansion of the articular surface of the distal tibia and increased degree of talar wedging), indicating that these traits are sensitive to climbing behavior. However, our analyses did not reveal any signatures of climbing behavior in the ankles of habitually climbing hunter-gatherers. These results suggest that the detection of fine-grained differences in human locomotor behaviors at the ankle joint, particularly those associated with arboreality, may be obscured by the functional demands of terrestrial bipedalism. Accordingly, it may be difficult to use population-level characteristics of ankle morphology to make inferences about the climbing behavior of hominins in the fossil record, even when facultative arborealism is associated with key fitness benefits