60 research outputs found

    Late Quaternary Faulting History of the Carrizal and Related Faults, La Paz Region, Baja California Sur, Mexico

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    The southwest margin of the Gulf of California has an array of active normal faults despite this being an oblique-divergent plate boundary with spreading centers that localized deformation along the plate boundary 2–3 million years ago. The Carrizal and Centenario faults form the western border fault of the Gulf of California marginal fault system within and south of La Paz Bay, and ∼20–30 km west of the capital city of La Paz, Baja California Sur, Mexico. Geologic and geomorphic mapping, optically stimulated luminescence (OSL) geochronology, and paleoseismic investigations onshore, compressed high-intensity radar pulse (CHIRP) profiling offshore, and analysis of uplifted marine terraces in the footwall of the offshore Carrizal fault provide some of the first numerical and geometrical constraints on late Pleistocene–Holocene faulting along the Carrizal fault. The onshore Carrizal fault has ruptured with up to ∼1–2 m of vertical displacement per event, likely producing ∼M 6.3–6.9 earthquakes, and at least two to three surface rupturing earthquakes have occurred since 22 ka. Onshore paleoseismic excavations and uplifted marine terraces on the western side of La Paz Bay both suggest offset rates of 0.1–0.2 mm/yr, with a footwall uplift rate of 0.13 mm/yr since 128 ka, and an approximately constant rate since marine oxygen-isotope stage (MIS) 11 terraces (420 ka). A CHIRP survey identified underwater fault scarps with heights ranging from 21 to 86 m on the Carrizal fault in La Paz Bay and from 3 to 5 m along the Centenario fault. The offshore Carrizal fault lies 8–10 km east of the western edge of La Paz Bay, forming a right step from the onshore Carrizal fault. The offshore Carrizal fault is the oldest fault of the fault system, and the fault likely grew in the latest Miocene to Pliocene in a complex way to the south toward the onshore Centenario and Carrizal faults. When the Alarcon spreading center started its modern rates at 2.4 Ma, the Carrizal fault likely slowed to the 0.1–0.2 mm/yr rates of the late Quaternary determined in this study

    Writing materiality into management and organization studies through and with Luce Irigaray

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    YesThere is increasing recognition in management and organization studies of the importance of materiality as an aspect of discourse, while the neglect of materiality in post-structuralist management and organization theory is currently the subject of much discussion. This article argues that this turn to materiality may further embed gender discrimination. We draw on Luce Irigaray’s work to highlight the dangers inherent in masculine discourses of materiality. We discuss Irigaray’s identification of how language and discourse elevate the masculine over the feminine so as to offer insights into ways of changing organizational language and discourses so that more beneficial, ethicallyfounded identities, relationships and practices can emerge. We thus stress a political intent that aims to liberate women and men from phallogocentrism. We finally take forward Irigaray’s ideas to develop a feminist écriture of/for organization studies that points towards ways of writing from the body. The article thus not only discusses how inequalities may be embedded within the material turn, but it also provides a strategy that enriches the possibilities of overcoming them from within

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Environmentalism, pre-environmentalism, and public policy

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    In the last decade, thousands of new grassroots groups have formed to oppose environmental pollution on the basis that it endangers their health. These groups have revitalized the environmental movement and enlarged its membership well beyond the middle class. Scientists, however, have been unable to corroborate these groups' claims that exposure to pollutants has caused their diseases. For policy analysts this situation appears to pose a choice between democracy and science. It needn't. Instead of evaluating the grassroots groups from the perspective of science, it is possible to evaluate science from the perspective of environmentalism. This paper argues that environmental epidemiology reflects ‘pre-environmentalist’ assumptions about nature and that new ideas about nature advanced by the environmental movement could change the way scientists collect and interpret data.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45449/1/11077_2005_Article_BF01006494.pd

    Virus-Mediated Transduction of Murine Retina with Adeno-Associated Virus: Effects of Viral Capsid and Genome Size

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    Gene therapy vectors based on adeno-associated viruses (AAVs) show promise for the treatment of retinal degenerative diseases. In prior work, subretinal injections of AAV2, AAV5, and AAV2 pseudotyped with AAV5 capsids (AAV2/5) showed variable retinal pigmented epithelium (RPE) and photoreceptor cell transduction, while AAV2/1 predominantly transduced the RPE. To more thoroughly compare the efficiencies of gene transfer of AAV2, AAV3, AAV5, and AAV6, we quantified, using stereological methods, the kinetics and efficiency of AAV transduction to mouse photoreceptor cells. We observed persistent photoreceptor and RPE transduction by AAV5 and AAV2 up to 31 weeks and found that AAV5 transduced a greater volume than AAV2. AAV5 containing full-length or half-length genomes and AAV2/5 transduced comparable numbers of photoreceptor cells with similar rates of onset of expression. Compared to AAV2, AAV5 transduced significantly greater numbers of photoreceptor cells at 5 and 15 weeks after surgery (greater than 1,000 times and up to 400 times more, respectively). Also, there were 30 times more genome copies in eyes injected with AAV2/5 than in eyes injected with AAV2. Comparing AAVs with half-length genomes, AAV5 transduced only four times more photoreceptor cells than AAV2 at 5 weeks and nearly equivalent numbers at 15 weeks. The enhancement of transduction was seen at the DNA level, with 50 times more viral genome copies in retinas injected with AAV having short genomes than in retinas injected with AAV containing full-length ones. Subretinal injection of AAV2/6 showed only RPE transduction at 5 and 15 weeks, while AAV2/3 did not transduce retinal cells. We conclude that varying genome length and AAV capsids may allow for improved expression and/or gene transfer to specific cell types in the retina

    Middle Pleistocene environments, landscapes and tephrostratigraphy of the Armenian Highlands: evidence from Bird Farm 1, Hrazdan Valley

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    The significance of the southern Caucasus in understanding Pleistocene hominin expansions is well established. However, the palaeoenvironments in which Palaeolithic occupation of the region took place are presently poorly defined. The Hrazdan river valley, Armenian Highlands, contains a rich Palaeolithic record alongside Middle Pleistocene volcanic, fluvial and lacustrine strata, and thus offer exciting potential for palaeoenvironmental reconstruction. We present the first results of sedimentological, geochemical, tephrostratigraphical and biological (diatoms) study of the sequence of Bird Farm 1, located in the central part of the valley. These data show six phases of landscape development during the interval 440–200 ka. The sequence represents the first quantitative Pleistocene diatom record from the Armenian Highlands and the southern Caucasus, and indicates the persistence of a deep, stratified lacustrine system, with evidence for changing lake productivity that is tentatively linked to climate. Furthermore, major element chemical characterization of visible and crypto-tephra horizons in the sequence enables the first stages of the development of a regional tephrostratigraphy. Together, the evidence from Bird Farm 1 demonstrates the importance of lacustrine archives in the region for palaeoenvironmental reconstruction and highlights the potential for linkages between archives on both a local and regional scale
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