A geochemical and petrological study of the crystalline basement and associated megablocks of the Eyreville-B drillcore, Chesapeake Bay impact structure, USA

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2015.The ca. 36 Ma Chesapeake Bay impact event on the east coast of Virginia, USA, formed an 85 km complex crater in Cretaceous to Eocene sediments and underlying crystalline basement rocks belonging to the Appalachian orogen. Appalachian rocks are well exposed along the Appalachian Mountains to the west, however, little is known of the basement along the Atlantic Coastal Plain owing to the covering sedimentary sequence. This study investigates the crystalline rocks intersected by the 2006 ICDP (International Continental Scientific Drilling Program) – USGS (United States Geological Survey) drilling of the Chesapeake Bay impact structure (CBIS) on the Eyreville Farm near Cape Charles, Virginia. The crystalline rocks of the Eyreville-B borehole core are found in the lower basement-derived section (between 1551.19 m and 1766.32 m depth), in the amphibolite megablock (between 1376.38 m and 1389.35 m depth) and in the upper granite megablock (between 1095.74 m and 1371.11 m depth). The lower basement-derived section consists of foliated metasediments, which include mica schist, amphibolite and calc-silicate rock, and coarse-grained to pegmatitic granite. The amphibolite megablock is a black to dark grey to dark green, fine- to medium-grained, locally foliated, relatively homogenous, lithic block. The upper granite megablock is divided into gneissic and massive varieties, with a minor component of biotite schist xenoliths. The crystalline rocks contain foliations and related structures, fractures and breccias, microstructures and porphyroblast microstructures; however, none of the three lithic blocks is in situ and, consequently, structural measurements cannot be fully interpreted tectonically. Mineral assemblages and microstructural evidence in the mica schists suggest the rocks in the lower basement-derived section experienced a syn-D1 amphibolite facies peak metamorphic event (M1a) followed by retrograde metamorphic conditions (M1b) limited to D1b mylonitic and D2 brittle deformation. Similar metamorphic conditions in the upper megablocks suggest that the three sections likely formed part of a single metamorphic terrane. iv Geochemistry in the lower basement-derived mica schists revealed a strong intermediate igneous provenance, whereas the upper megablock biotite schist xenoliths showed a quartzose sedimentary provenance; the precursors to both appear to have been deposited in active continental margin settings. The lower basement-derived amphibolite appears to be derived from a sedimentary source. The precursor to the upper amphibolite megablock, on the other hand, was probably a tholeittic gabbro generated in an island arc setting. The peraluminous, S-type nature of the lower basement-derived granite suggests it was most likely generated in a within-plate tectonic setting. In contrast, the massive and gneissic granites from the upper megablock are metaluminous, I-type granites that were most likely generated in a syn-collisional environment. Metamorphic conditions of the M1 event were constrained using mineral assemblages mainly from the lower basement-derived section, which limited the X(H2O) value to 0.8, P to >0.4 GPa and the T range to 600-670°C. Using the 0.4 GPa pressure constraint, Zr-in-rutile thermometry revealed a peak metamorphic temperature for the M1 event of 606 ± 18°C, which is consistent with mid-amphibolite facies metamorphism. These estimates suggest a very steep geothermal gradient approaching ~44°C/km. Rutile U/Pb geochronology revealed that the M1 event recorded in the lower basement-derived metasediments occurred at 259 ± 13 Ma, with Ar/Ar geochronology indicating the cooling path through to greenschist metamorphic conditions. Zircon U/Pb SHRIMP geochronology performed by Horton et al. (2009b) on the massive and gneissic megablock granites dated their crystallisation ages at 254 ± 3 Ma and 615 ± 7 Ma, respectively, with the former age in agreement with the rutile U/Pb peak metamorphism results from the lower basement-derived section. These ages, together with petrography, structural observations, geochemistry and geothermobarometry suggests that the amphibolite and granite megablocks form part of the same metamorphic terrane as the lower basement-derived section and that the D1 and M1 events recorded in the lower basement-derived section and upper megablocks of the Eyreville-B borehole core likely occurred during the late stages of the Alleghanian orogeny. v Based on mineralogy, geochemistry, metamorphic grade and structural evidence, comparisons with the neighbouring terranes within the Appalachian basement beneath the Atlantic Coastal Plain sediments suggest that the lower basement-derived and upper amphibolite and granite megablocks of the Eyreville-B borehole core most likely formed part of the Hatteras terrane prior to the Chesapeake Bay impact event. This terrane, together with 5 other terranes, forms part of the Carolina Zone, a peri-Gondwanan micro-continent formed by the amalgamation of magmatic arcs during the Penobscottian and Taconian orogenies, which was then accreted onto the Laurentian margin during the Salinic and Acadian orogenies

Chimpanzee vocal communication: what we know from the wild

Vocal communication plays a vital role in the daily lives of our closest living relatives, chimpanzees. Unpacking the adaptive function of vocalisations, and the cognitive mechanisms underlying their production and comprehension is not only crucial for understanding chimpanzee behaviour, but also for inferring the capacities of our last common ancestors. Here, we review how observational and experimental methods have advanced our understanding of the vocal production and comprehension of wild chimpanzees. We discuss the impact of social and ecological factors on chimpanzee vocal communication, and review the inroads that have been made in elucidating the cognitive processes underpinning call production. We highlight approaches that may offer substantial future advances in knowledge and argue that whilst challenging to collect, data from wild populations is critical to building a comprehensive and accurate understanding of the communicative and cognitive abilities of our closest living relatives, and to tracing the evolutionary roots of human language

Degraded and computer-generated speech processing in a bonobo

The human auditory system is capable of processing human speech even in situations when it has been heavily degraded, such as during noise-vocoding, when frequency domain-based cues to phonetic content are strongly reduced. This has contributed to arguments that speech processing is highly specialized and likely a de novo evolved trait in humans. Previous comparative research has demonstrated that a language competent chimpanzee was also capable of recognizing degraded speech, and therefore that the mechanisms underlying speech processing may not be uniquely human. However, to form a robust reconstruction of the evolutionary origins of speech processing, additional data from other closely related ape species is needed. Specifically, such data can help disentangle whether these capabilities evolved independently in humans and chimpanzees, or if they were inherited from our last common ancestor. Here we provide evidence of processing of highly varied (degraded and computer-generated) speech in a language competent bonobo, Kanzi. We took advantage of Kanzi’s existing proficiency with touchscreens and his ability to report his understanding of human speech through interacting with arbitrary symbols called lexigrams. Specifically, we asked Kanzi to recognise both human (natural) and computer-generated forms of 40 highly familiar words that had been degraded (noise-vocoded and sinusoidal forms) using a match-to-sample paradigm. Results suggest that—apart from noise-vocoded computer-generated speech—Kanzi recognised both natural and computer-generated voices that had been degraded, at rates significantly above chance. Kanzi performed better with all forms of natural voice speech compared to computer-generated speech. This work provides additional support for the hypothesis that the processing apparatus necessary to deal with highly variable speech, including for the first time in nonhuman animals, computer-generated speech, may be at least as old as the last common ancestor we share with bonobos and chimpanzees

Unveiling the mechanism of the in situ> formation of 3d fiber macroassemblies with controlled properties

Electrospinning technique is well-known for the generation of different fibers. While it is a "simple" technique, it lies in the fact that the fibers are typically produced in the form of densely packed two-dimensional (2D) mats with limited thickness, shape, and porosity. The highly demanded three-dimensional (3D) fiber assemblies have been explored by time-consuming postprocessing and/or complex setup modifications. Here, we use a classic electrospinning setup to directly produce 3D fiber macrostructures only by modulating the spinning solution. Increasing solution conductivity modifies electrodynamic jet behavior and fiber assembling process; both are observed in situ using a high-speed camera. More viscous solutions render thicker fibers that own enhanced mechanical stiffness as examined by finite element analysis. We reveal the correlation between the universal solution parameters and the dimensionality of fiber assemblies, thereof, enlightening the design of more "3D spinnable" solutions that are compatible with any commercial electrospinning equipment. After a calcination step, ultralightweight ceramic fiber assemblies are generated. These inexpensive materials can clean up exceptionally large fractions of oil spillages and provide high-performance thermal insulation. This work would drive the development and scale-up production of next-generation 3D fiber materials for engineering, biomedical, and environmental applications

Declarative referential gesturing in a wild chimpanzee (Pan troglodytes)

Humans are argued to be unique in their ability and motivation to share attention with others about external entities—sharing attention for sharing’s sake. Indeed, in humans, using referential gestures declaratively to direct the attention of others toward external objects and events emerges in the first year of life. In contrast, wild great apes seldom use referential gestures, and when they do, it seems to be exclusively for imperative purposes. This apparent species difference has fueled the argument that the motivation and ability to share attention with others is a human-specific trait with important downstream consequences for the evolution of our complex cognition [M. Tomasello, Becoming Human (2019)]. Here, we report evidence of a wild ape showing a conspecific an item of interest. We provide video evidence of an adult female chimpanzee, Fiona, showing a leaf to her mother, Sutherland, in the context of leaf grooming in Kibale Forest, Uganda. We use a dataset of 84 similar leaf-grooming events to explore alternative explanations for the behavior, including food sharing and initiating dyadic grooming or playing. Our observations suggest that in highly specific social conditions, wild chimpanzees, like humans, may use referential showing gestures to direct others’ attention to objects simply for the sake of sharing. The difference between humans and our closest living relatives in this regard may be quantitative rather than qualitative, with ramifications for our understanding of the evolution of human social cognition

Field testing of biohybrid robotic jellyfish to demonstrate enhanced swimming speeds

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Xu, N. W., Townsend, J. P., Costello, J. H., Colin, S. P., Gemmell, B. J., & Dabiri, J. O. Field testing of biohybrid robotic jellyfish to demonstrate enhanced swimming speeds. Biomimetics, 5(4), (2020): E64, doi:10.3390/biomimetics5040064.Biohybrid robotic designs incorporating live animals and self-contained microelectronic systems can leverage the animals’ own metabolism to reduce power constraints and act as natural chassis and actuators with damage tolerance. Previous work established that biohybrid robotic jellyfish can exhibit enhanced speeds up to 2.8 times their baseline behavior in laboratory environments. However, it remains unknown if the results could be applied in natural, dynamic ocean environments and what factors can contribute to large animal variability. Deploying this system in the coastal waters of Massachusetts, we validate and extend prior laboratory work by demonstrating increases in jellyfish swimming speeds up to 2.3 times greater than their baseline, with absolute swimming speeds up to 6.6 ± 0.3 cm s−1. These experimental swimming speeds are predicted using a hydrodynamic model with morphological and time-dependent input parameters obtained from field experiment videos. The theoretical model can provide a basis to choose specific jellyfish with desirable traits to maximize enhancements from robotic manipulation. With future work to increase maneuverability and incorporate sensors, biohybrid robotic jellyfish can potentially be used to track environmental changes in applications for ocean monitoring.This work was supported by the National Science Foundation (NSF) Graduate Research Fellowship Program (GRFP) awarded to N.W.X

Sexual Dimorphism in Hematocrit Response Following Red Blood Cell Transfusion of Critically Ill Surgical Patients

The change in hematocrit (ΔHct) following packed red blood cell (pRBCs) transfusion is a clinically relevant measurement of transfusion efficacy that is influenced by post-transfusion hemolysis. Sexual dimorphism has been observed in critical illness and may be related to gender-specific differences in immune response. We investigated the relationship between both donor and recipient gender and ΔHct in an analysis of all pRBCs transfusions in our surgical intensive care unit (2006–2009). The relationship between both donor and recipient gender and ΔHct (% points) was assessed using both univariate and multivariable analysis. A total of 575 units of pRBCs were given to 342 patients; 289 (49.9%) donors were male. By univariate analysis, ΔHct was significantly greater for female as compared to male recipients (3.81% versus 2.82%, resp., P < 0.01). No association was observed between donor gender and ΔHct, which was 3.02% following receipt of female blood versus 3.23% following receipt of male blood (P = 0.21). By multivariable analysis, recipient gender remained associated significantly with ΔHct (P < 0.01). In conclusion, recipient gender is independently associated with ΔHct following pRBCs transfusion. This association does not appear related to either demographic or anthropomorphic factors, raising the possibility of gender-related differences in recipient immune response to transfusion

Degraded and computer-generated speech processing in a bonobo

The human auditory system is capable of processing human speech even in situations when it has been heavily degraded, such as during noise-vocoding, when frequency domain-based cues to phonetic content are strongly reduced. This has contributed to arguments that speech processing is highly specialized and likely a de novo evolved trait in humans. Previous comparative research has demonstrated that a language competent chimpanzee was also capable of recognizing degraded speech, and therefore that the mechanisms underlying speech processing may not be uniquely human. However, to form a robust reconstruction of the evolutionary origins of speech processing, additional data from other closely related ape species is needed. Specifically, such data can help disentangle whether these capabilities evolved independently in humans and chimpanzees, or if they were inherited from our last common ancestor. Here we provide evidence of processing of highly varied (degraded and computer-generated) speech in a language competent bonobo, Kanzi. We took advantage of Kanzi’s existing proficiency with touchscreens and his ability to report his understanding of human speech through interacting with arbitrary symbols called lexigrams. Specifically, we asked Kanzi to recognise both human (natural) and computer-generated forms of 40 highly familiar words that had been degraded (noise-vocoded and sinusoidal forms) using a match-to-sample paradigm. Results suggest that—apart from noise-vocoded computer-generated speech—Kanzi recognised both natural and computer-generated voices that had been degraded, at rates significantly above chance. Kanzi performed better with all forms of natural voice speech compared to computer-generated speech. This work provides additional support for the hypothesis that the processing apparatus necessary to deal with highly variable speech, including for the first time in nonhuman animals, computer-generated speech, may be at least as old as the last common ancestor we share with bonobos and chimpanzees

Common evolutionary origin of acoustic communication in choanate vertebrates

Acoustic communication, broadly distributed along the vertebrate phylogeny, plays a fundamental role in parental care, mate attraction and various other behaviours. Despite its importance, comparatively less is known about the evolutionary roots of acoustic communication. Phylogenetic comparative analyses can provide insights into the deep time evolutionary origin of acoustic communication, but they are often plagued by missing data from key species. Here we present evidence for 53 species of four major clades (turtles, tuatara, caecilian and lungfish) in the form of vocal recordings and contextual behavioural information accompanying sound production. This and a broad literature-based dataset evidence acoustic abilities in several groups previously considered non-vocal. Critically, phylogenetic analyses encompassing 1800 species of choanate vertebrates reconstructs acoustic communication as a homologous trait, and suggests that it is at least as old as the last common ancestor of all choanate vertebrates, that lived approx. 407 million years before present

West Nile virus transmission in resident birds, Dominican Republic

Centers for Disease Control and Prevention http://www.cdc.gov/ncidod/EID/vol9no10/03-0222.htmWe report West Nile virus (WNV) activity in the Dominican Republic for the first time. Specific anti-WNV antibodies were detected in 5 (15%) of 33 resident birds sampled at one location in November 2002. One seropositive bird was <4 months old, indicating a recent infection