Imagining Margaret Garner: The Tragic Life of an American Woman

There is limited information on the life of the nineteenth century female slave with most details compiled from the narratives of well-known women such as Sojourner Truth. Professor Erlene Stetson and other historians argue that scholars treat slavery as a male phenomenon and the female is merely looked upon as a breeder, while noted African-American activist Angela Davis calls for a more accurate portrayal to debunk derogatory myths. This paper addresses the issue of image with the argument that the enslaved African-American woman possessed no image of her own. It focuses on the story of a runaway female slave named Margaret Garner, who chose to murder one of her children rather than return that child to the bonds of slavery. She gained international attention, but quickly disappeared from history. The story of Garner as a slave, fugitive, resistor and heroine were all images of one woman realized through the notion of others; her story required a twentieth-century author, Toni Morrison, to revive her memory. Image plays an important part in how people, places and events are regarded. A new wave of historians has ignited a revolution of study on the still developing image of the African- American female slave, with the goal of employing new methods of thinking and research to form coherent conclusions

Characteristics of Some Fruiting Plant Species in Northwest Arkansas, and the Avian Assemblages that Feed on Them

Fruits continue to be recognized as an important food source for birds in temperate areas, particularly during the fall migration period. More than 20 species of plants producing fleshy fruits are found in the Arkansas Ozarks. However, only a few of these appear to be important resources for birds during the fall migration period (August - October). Among those are sassafras (Sassafras albidum), gray-backed grape (Vitis cinerea), black cherry (Prunus serotina), hercules club (Araliaspinosa) and pokeweed (Phytolacca americana). Over the past 4 years, we have documented the physical and nutritional characteristics of those fruits and taken observational data on the assemblages of birds eating them. It appears that avian species assemblages feeding on fruits are partially determined by the physical and nutritional contents of those fruits. Sassafras is extremely lipid-rich and higher in caloric content than the other species of fruits. It appears to be eaten almost exclusively by larger birds, perhaps be due to the large size of its fruits, which may exceed gape width of many smaller bird species. Prunus and Vitis are also eaten by a large number of avian species. Phytolacca was eaten only by a small number of primarily resident bird species and often persisted into the winter. Reasons for this pattern are not clear, as it was relatively similar to the other fruits inmost characteristics. Aralia was seen being eaten by only a few species of birds but is less common than the other species, and its small fruits may not be as attractive as those of the other species. Compared to other places in the east, there appear to be a relatively low number of migratory frugivorous birds in northwestern Arkansas. Overall, there were very few species noted at any fruiting plants, and a large proportion of the total assemblage of birds was comprised of resident species

Dynamic earthquake rupture preserved in a creeping serpentinite shear zone

Laboratory experiments on serpentinite suggest that extreme dynamic weakening at earthquake slip rates is accompanied by amorphisation, dehydration and possible melting. However, hypotheses arising from experiments remain untested in nature, because earthquake ruptures have not previously been recognised in serpentinite shear zones. Here we document the progressive formation of high-temperature reaction products that formed by coseismic amorphisation and dehydration in a plate boundary-scale serpentinite shear zone. The highest-temperature products are aggregates of nanocrystalline olivine and enstatite, indicating minimum peak coseismic temperatures of ca. 925 ± 60 °C. Modelling suggests that frictional heating during earthquakes of magnitude 2.7–4 can satisfy the petrological constraints on the coseismic temperature profile, assuming that coseismic fluid storage capacity and permeability are increased by the development of reaction-enhanced porosity. Our results indicate that earthquake ruptures can propagate through serpentinite shear zones, and that the signatures of transient frictional heating can be preserved in the fault rock record

The Space Interferometry Mission Astrometric Grid Giant-Star Survey. I. Stellar Parameters and Radial Velocity Variability

We present results from a campaign of multiple epoch echelle spectroscopy of relatively faint (V = 9.5-13.5 mag) red giants observed as potential astrometric grid stars for the Space Interferometry Mission (SIM PlanetQuest). Data are analyzed for 775 stars selected from the Grid Giant Star Survey spanning a wide range of effective temperatures (Teff), gravities and metallicities. The spectra are used to determine these stellar parameters and to monitor radial velocity (RV) variability at the 100 m/s level. The degree of RV variation measured for 489 stars observed two or more times is explored as a function of the inferred stellar parameters. The percentage of radial velocity unstable stars is found to be very high -- about 2/3 of our sample. It is found that the fraction of RV-stable red giants (at the 100 m/s level) is higher among stars with Teff \sim 4500 K, corresponding to the calibration-independent range of infrared colors 0.59 < (J-K_s)_0 < 0.73. A higher percentage of RV-stable stars is found if the additional constraints of surface gravity and metallicity ranges 2.3< log g < 3.2 and -0.5 < [Fe/H] < -0.1, respectively, are applied. Selection of stars based on only photometric values of effective temperature (4300 K < Teff < 4700 K) is a simple and effective way to increase the fraction of RV-stable stars. The optimal selection of RV-stable stars, especially in the case when the Washington photometry is unavailable, can rely effectively on 2MASS colors constraint 0.59 < (J-K_s)_0 < 0.73. These results have important ramifications for the use of giant stars as astrometric references for the SIM PlanetQuest.Comment: Astronomical Journal, in press, 22 pages, 11 Postscript figures, uses aastex.cl

The internal structure and composition of a plate-boundary-scale serpentinite shear zone: the Livingstone Fault, New Zealand

Abstract. Deciphering the internal structure and composition of large serpentinite-dominated shear zones will lead to an improved understanding of the rheology of the lithosphere in a range of tectonic settings. The Livingstone Fault in New Zealand is a terrane-bounding structure that separates the basal portions (peridotite; serpentinised peridotite; metagabbros) of the Dun Mountain Ophiolite Belt from the quartzofeldspathic schists of the Caples and Aspiring Terrane. Field and microstructural observations from 11 localities along a strike length of ca. 140 km show that the Livingstone Fault is a steeply dipping, serpentinite-dominated shear zone tens of metres to several hundred metres wide. The bulk shear zone has a pervasive scaly fabric that wraps around fractured and faulted pods of massive serpentinite, rodingite and partially metasomatised quartzofeldspathic schist up to a few tens of metres long. S–C fabrics and lineations in the shear zone consistently indicate a steep east-side-up shear sense, with significant local dispersion in kinematics where the shear zone fabrics wrap around pods. The scaly fabric is dominated (>98 % vol) by fine-grained (≪10 µm) fibrous chrysotile and lizardite–polygonal serpentine, but infrequent (<1 % vol) lenticular relicts of antigorite are also preserved. Dissolution seams and foliation surfaces enriched in magnetite, as well as the widespread growth of fibrous chrysotile in veins and around porphyroclasts, suggest that bulk shear zone deformation involved pressure–solution. Syn-kinematic metasomatic reactions occurred along all boundaries between serpentinite, schist and rodingite, forming multigenerational networks of nephritic tremolite veins that are interpreted to have caused reaction hardening within metasomatised portions of the shear zone. We propose a conceptual model for plate-boundary-scale serpentinite shear zones which involves bulk-distributed deformation by pressure–solution creep, accompanied by a range of physical (e.g. faulting in pods and wall rocks; smearing of magnetite along fault surfaces) or chemical (e.g. metasomatism) processes that result in localised brittle deformation within creeping shear zone segments

Earliest evidence of herd-living and age segregation amongst dinosaurs

Sauropodomorph dinosaurs dominated the herbivorous niches during the first 40 million years of dinosaur history (Late Triassic–Early Jurassic), yet palaeobiological factors that influenced their evolutionary success are not fully understood. For instance, knowledge on their behaviour is limited, although herding in sauropodomorphs has been well documented in derived sauropods from the Late Jurassic and Cretaceous. Here we report an exceptional fossil occurrence from Patagonia that includes over 100 eggs and skeletal specimens of 80 individuals of the early sauropodomorph Mussaurus patagonicus, ranging from embryos to fully-grown adults, with an Early Jurassic age as determined by high-precision U–Pb zircon geochronology. Most specimens were found in a restricted area and stratigraphic interval, with some articulated skeletons grouped in clusters of individuals of approximately the same age. Our new discoveries indicate the presence of social cohesion throughout life and age-segregation within a herd structure, in addition to colonial nesting behaviour. These findings provide the earliest evidence of complex social behaviour in Dinosauria, predating previous records by at least 40 My. The presence of sociality in different sauropodomorph lineages suggests a possible Triassic origin of this behaviour, which may have influenced their early success as large terrestrial herbivores.Fil: Pol, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; ArgentinaFil: Mancuso, Adriana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Smith, Roger M. H.. University of the Witwatersrand; SudáfricaFil: Marsicano, Claudia Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Ramezani, Jahandar. Massachusetts Institute of Technology; Estados UnidosFil: Cerda, Ignacio Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Otero, Alejandro. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; ArgentinaFil: Fernandez, Vincent. European Synchrotron Radiation; Franci

Genomic resources for Myzus persicae: EST sequencing, SNP identification, and microarray design

<p>Abstract</p> <p>Background</p> <p>The green peach aphid, <it>Myzus persicae </it>(Sulzer), is a world-wide insect pest capable of infesting more than 40 plant families, including many crop species. However, despite the significant damage inflicted by <it>M. persicae </it>in agricultural systems through direct feeding damage and by its ability to transmit plant viruses, limited genomic information is available for this species.</p> <p>Results</p> <p>Sequencing of 16 <it>M. persicae </it>cDNA libraries generated 26,669 expressed sequence tags (ESTs). Aphids for library construction were raised on <it>Arabidopsis thaliana</it>, <it>Nicotiana benthamiana</it>, <it>Brassica oleracea, B. napus</it>, and <it>Physalis floridana </it>(with and without <it>Potato leafroll virus </it>infection). The <it>M. persicae </it>cDNA libraries include ones made from sexual and asexual whole aphids, guts, heads, and salivary glands. <it>In silico </it>comparison of cDNA libraries identified aphid genes with tissue-specific expression patterns, and gene expression that is induced by feeding on <it>Nicotiana benthamiana</it>. Furthermore, 2423 genes that are novel to science and potentially aphid-specific were identified. Comparison of cDNA data from three aphid lineages identified single nucleotide polymorphisms that can be used as genetic markers and, in some cases, may represent functional differences in the protein products. In particular, non-conservative amino acid substitutions in a highly expressed gut protease may be of adaptive significance for <it>M. persicae </it>feeding on different host plants. The Agilent eArray platform was used to design an <it>M. persicae </it>oligonucleotide microarray representing over 10,000 unique genes.</p> <p>Conclusion</p> <p>New genomic resources have been developed for <it>M. persicae</it>, an agriculturally important insect pest. These include previously unknown sequence data, a collection of expressed genes, molecular markers, and a DNA microarray that can be used to study aphid gene expression. These resources will help elucidate the adaptations that allow <it>M. persicae </it>to develop compatible interactions with its host plants, complementing ongoing work illuminating plant molecular responses to phloem-feeding insects.</p

Optogenetics design of mechanistically-based stimulation patterns for cardiac defibrillation

Current rescue therapies for life-threatening arrhythmias ignore the pathological electro-anatomical substrate and base their efficacy on a generalized electrical discharge. Here, we developed an all-optical platform to examine less invasive defibrillation strategies. An ultrafast wide-field macroscope was developed to optically map action potential propagation with a red-shifted voltage sensitive dye in whole mouse hearts. The macroscope was implemented with a random-access scanning head capable of drawing arbitrarily-chosen stimulation patterns with sub-millisecond temporal resolution allowing precise epicardial activation of Channelrhodopsin2 (ChR2). We employed this optical system in the setting of ventricular tachycardia to optimize mechanistic, multi-barrier cardioversion/defibrillation patterns. Multiple regions of conduction block were created with a very high cardioversion efficiency but with lower energy requirements as compared to whole ventricle interventions to interrupt arrhythmias. This work demonstrates that defibrillation energies can be substantially reduced by applying discrete stimulation patterns and promotes the progress of current anti-arrhythmic strategies

Hydroxymethylglutaryl-CoA reductase inhibition with simvastatin in acute lung injury to reduce pulmonary dysfunction (HARP-2) trial : study protocol for a randomized controlled trial

Acute lung injury (ALI) is a common devastating clinical syndrome characterized by life-threatening respiratory failure requiring mechanical ventilation and multiple organ failure. There are in vitro, animal studies and pre-clinical data suggesting that statins may be beneficial in ALI. The Hydroxymethylglutaryl-CoA reductase inhibition with simvastatin in Acute lung injury to Reduce Pulmonary dysfunction (HARP-2) trial is a multicenter, prospective, randomized, allocation concealed, double-blind, placebo-controlled clinical trial which aims to test the hypothesis that treatment with simvastatin will improve clinical outcomes in patients with ALI