427 research outputs found

    The Twentieth Century Record of Inequality and Poverty in the United States

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    When the twentieth century is viewed as a whole, no clear trend in income inequality emerges. Inequality was high and rising during the first three decades and peaked during the Depression. It fell sharply during World War II and remained at the lower level in the 1950s and 1960s. From the 1970s through the mid-1990s inequality steadily increased to levels not seen since World War II, though well below those during the first three decades. The rate of poverty exhibited a long-run downward trend from about 60–70 percent in the earlier years of the century to the 12–14 percent range in recent years, with considerable fluctuation around this secular trend. Changes in inequality were produced largely by demographic and technological changes, the growth and decline of various industries, changes in patterns of international trade, cyclical unemployment, and World War II. The primary drivers of the rate of poverty were economic growth and factors that produced changes in income inequality, particularly demographic change and unemployment. Public policy has reduced the market-generated level of inequality, but since 1950 has had little effect on the trend in inequality. Prior to 1950, the growth of government, and particularly the introduction of a broadly based income tax during World War II, coincided with and partly produced the sharp downward shift in inequality of that era. Government had little effect on poverty rates until 1950. Public income transfer programs have reduced poverty rates appreciably in recent decades. Since World War II, when they have been on a large enough scale to matter, changes in tax and transfer policy have tended to reinforce market-generated trends in inequality and poverty rather than offset them.

    Universal Formulae for Percolation Thresholds

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    A power law is postulated for both site and bond percolation thresholds. The formula writes pc=p0[(d1)(q1)]ad bp_c=p_0[(d-1)(q-1)]^{-a}d^{\ b}, where dd is the space dimension and qq the coordination number. All thresholds up to dd\rightarrow \infty are found to belong to only three universality classes. For first two classes b=0b=0 for site dilution while b=ab=a for bond dilution. The last one associated to high dimensions is characterized by b=2a1b=2a-1 for both sites and bonds. Classes are defined by a set of value for {p0; a}\{p_0; \ a\}. Deviations from available numerical estimates at d7d \leq 7 are within ±0.008\pm 0.008 and ±0.0004\pm 0.0004 for high dimensional hypercubic expansions at d8d \geq 8. The formula is found to be also valid for Ising critical temperatures.Comment: 11 pages, latex, 3 figures not include

    Evidence for Trait-Based Dominance in Occupancy among Fossil Taxa and the Decoupling of Macroecological and Macroevolutionary Success

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    Biological systems provide examples of differential success among taxa, from ecosystems with a few dominant species (ecological success) to clades that possess far more species than sister clades (macroevolutionary success). Macroecological success, the occupation by a species or clade of an unusually high number of areas, has received less attention. If macroecological success reflects heritable traits, then successful species should be related. Genera composed of species possessing those traits should occupy more areas than genera with comparable species richness that lack such traits. Alternatively, if macroecological success reflects autapomorphic traits, then generic occupancy should be a by-product of species richness among genera and occupancy of constituent species. We test this using Phanerozoic marine invertebrates. Although temporal patterns of species and generic occupancy are strongly correlated, inequality in generic occupancy typically is greater than expected. Genus-level patterns cannot be explained solely with species-level patterns. Within individual intervals, deviations between the observed and expected generic occupancy correlate with the number of lithological units (stratigraphic formations), particularly after controlling for geographic range and species richness. However, elevated generic occupancy is unrelated to or negatively associated with either generic geographic ranges or within-genus species richness. Our results suggest that shared traits among congeneric species encourage shortterm macroecological success without generating short-term macroevolutionary success. A broad niche may confer high occupancy but does not necessarily promote speciation. Supplemental files attached below (.zip

    Evidence for Trait-Based Dominance in Occupancy among Fossil Taxa and the Decoupling of Macroecological and Macroevolutionary Success

    Get PDF
    Biological systems provide examples of differential success among taxa, from ecosystems with a few dominant species (ecological success) to clades that possess far more species than sister clades (macroevolutionary success). Macroecological success, the occupation by a species or clade of an unusually high number of areas, has received less attention. If macroecological success reflects heritable traits, then successful species should be related. Genera composed of species possessing those traits should occupy more areas than genera with comparable species richness that lack such traits. Alternatively, if macroecological success reflects autapomorphic traits, then generic occupancy should be a by-product of species richness among genera and occupancy of constituent species. We test this using Phanerozoic marine invertebrates. Although temporal patterns of species and generic occupancy are strongly correlated, inequality in generic occupancy typically is greater than expected. Genus-level patterns cannot be explained solely with species-level patterns. Within individual intervals, deviations between the observed and expected generic occupancy correlate with the number of lithological units (stratigraphic formations), particularly after controlling for geographic range and species richness. However, elevated generic occupancy is unrelated to or negatively associated with either generic geographic ranges or within-genus species richness. Our results suggest that shared traits among congeneric species encourage shortterm macroecological success without generating short-term macroevolutionary success. A broad niche may confer high occupancy but does not necessarily promote speciation. Supplemental files attached below (.zip

    Evidence for Trait-Based Dominance in Occupancy among Fossil Taxa and the Decoupling of Macroecological and Macroevolutionary Success

    Get PDF
    Biological systems provide examples of differential success among taxa, from ecosystems with a few dominant species (ecological success) to clades that possess far more species than sister clades (macroevolutionary success). Macroecological success, the occupation by a species or clade of an unusually high number of areas, has received less attention. If macroecological success reflects heritable traits, then successful species should be related. Genera composed of species possessing those traits should occupy more areas than genera with comparable species richness that lack such traits. Alternatively, if macroecological success reflects autapomorphic traits, then generic occupancy should be a by-product of species richness among genera and occupancy of constituent species. We test this using Phanerozoic marine invertebrates. Although temporal patterns of species and generic occupancy are strongly correlated, inequality in generic occupancy typically is greater than expected. Genus-level patterns cannot be explained solely with species-level patterns. Within individual intervals, deviations between the observed and expected generic occupancy correlate with the number of lithological units (stratigraphic formations), particularly after controlling for geographic range and species richness. However, elevated generic occupancy is unrelated to or negatively associated with either generic geographic ranges or within-genus species richness. Our results suggest that shared traits among congeneric species encourage shortterm macroecological success without generating short-term macroevolutionary success. A broad niche may confer high occupancy but does not necessarily promote speciation. Supplemental files attached below (.zip

    The Sand Creek Massacre and the History of Greater Reconstruction in the American West

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    In the traditional U.S. historical narrative, the Civil War & Reconstruction era is a North vs. South story. Nevertheless, the era of western expansion, a central theme throughout the nineteenth century, has no contingent place within this traditional narrative. Meanwhile, the history of the American West and its diverse peoples appears in many textbooks as an unrelated albeit contemporaneous narrative. Separated by geographical regions, historians often do not examine these concurrent histories. However, many of these historical events and actors were interconnected. As I am interested in understanding the Reconstruction era’s national impact, I intend to explore how Reconstruction policies were enacted in the 1860s and 70s trans-Mississippi West, building which builds on the historical contributions of Historian Elliot West in “Greater Reconstruction,” which aims to reimagine a more national ideal of Reconstruction, not confined to the Southern states. Moreover, this era includes western Native peoples\u27 post-Civil War reform era history. This project aims to uncover the history of the Reconstruction of Native peoples by concentrating on the Southern Arapaho and Cheyenne of the Colorado plains territory. Elliott West’s “Greater Reconstruction” concept specifically connects mid-nineteenth-century race-making and nation-state-building political projects in the American South and West. For this project, I plan to center the 1864 Sand Creek massacre that took place in the southeastern Colorado Territory as a marking point in the Civil War in the West and Greater Reconstruction. This massacre involved the brutal murder and mutilation of an estimated 200 Cheyenne and Arapaho people by the U.S. Army. By contextualizing this massacre in terms of other Civil War-era Indian “wars,” I will be able to examine the federal government’s decision to investigate the attack on the Native people, which was not only a common occurrence but widely supported among military personnel. I will significantly rely on Congressional testimony and investigation reports (39th Congress, 2nd Session, U.S. Senate, Reports of Committees, No. 156.), along with Bureau of Indian Affairs records (Record Group 75.19.10). These sources will help me determine why this particular Native massacre received so much federal scrutiny. I also intend to put the Sand Creek investigation in a historical conversation with the federal government’s attempts to reconstruct the Southern Arapaho and Cheyenne through new treaty provisions (primarily in the Medicine Lodge Treaty of 1867) that forced them into reservation life in Native Territory. Rather than portraying these developments as contradictory, I hope to connect them by identifying their shared Greater Reconstruction-era political motivations as 19th-century Republicans attempted to build a politically and culturally unified nation. More broadly, I hope to shed light on an overlooked aspect of Greater Reconstruction and its complicated and often negative impact on the Arapaho people. In so doing, this project contributes to the growing inclusion of marginalized voices and perspectives in the history of Reconstruction, which is still primarily dominated by prominent American military and political figures. Finally, this project will take steps to clarify the meaning and legacy of this critical era of political reform and nation-state building concerning American society today

    Early Devonian non-trilobite arthropods from the Iberian Chains (North East, Spain)

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    Slightly sclerotised arthropods are described from shales of the Early Devonian age of the Axial Depression of the Cámaras river in Northeast Spain. The oldest records represent eurypterid fragments assigned to indeterminate Pterygotidae. They have been found in the early Pragian Nogueras Formation associated with land plant remains and rare marine invertebrates. The other two correspond to the first report of the phyllocarid Nahecaris in Spain. Nahecaris carlsi n. sp. is represented by a single complete specimen from the Pragian Santa Cruz Formation and Nahecaris sp. by another specimen from the Emsian Mariposas Formation. Both are associated with a rich marine fauna of various invertebrate groups. Environmentally, these arthropods occupied different areas from marginal marine (Pterygotidae indet.) to more open marine conditions (Nahecaris). The discovery of slightly sclerotised arthropods in several levels informs about the potential of the area for such type of preservation

    Early Devonian non-trilobite arthropods from the Iberian Chains (North East, Spain)

    Full text link
    Slightly sclerotised arthropods are described from shales of the Early Devonian age of the Axial Depression of the Cámaras river in Northeast Spain. The oldest records represent eurypterid fragments assigned to indeterminate Pterygotidae. They have been found in the early Pragian Nogueras Formation associated with land plant remains and rare marine invertebrates. The other two correspond to the first report of the phyllocarid Nahecaris in Spain. Nahecaris carlsi n. sp. is represented by a single complete specimen from the Pragian Santa Cruz Formation and Nahecaris sp. by another specimen from the Emsian Mariposas Formation. Both are associated with a rich marine fauna of various invertebrate groups. Environmentally, these arthropods occupied different areas from marginal marine (Pterygotidae indet.) to more open marine conditions (Nahecaris). The discovery of slightly sclerotised arthropods in several levels informs about the potential of the area for such type of preservation

    Dengue Virus Infection of Aedes aegypti Requires a Putative Cysteine Rich Venom Protein

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    Citation: Londono-Renteria, B., Troupin, A., Conway, M. J., Vesely, D., Ledizet, M., Roundy, C. M., . . . Colpitts, T. M. (2015). Dengue Virus Infection of Aedes aegypti Requires a Putative Cysteine Rich Venom Protein. Plos Pathogens, 11(10), 23. doi:10.1371/journal.ppat.1005202Dengue virus (DENV) is a mosquito-borne flavivirus that causes serious human disease and mortality worldwide. There is no specific antiviral therapy or vaccine for DENV infection. Alterations in gene expression during DENV infection of the mosquito and the impact of these changes on virus infection are important events to investigate in hopes of creating new treatments and vaccines. We previously identified 203 genes that were >= 5-fold differentially upregulated during flavivirus infection of the mosquito. Here, we examined the impact of silencing 100 of the most highly upregulated gene targets on DENV infection in its mosquito vector. We identified 20 genes that reduced DENV infection by at least 60% when silenced. We focused on one gene, a putative cysteine rich venom protein (SeqID AAEL000379; CRVP379), whose silencing significantly reduced DENV infection in Aedes aegypti cells. Here, we examine the requirement for CRVP379 during DENV infection of the mosquito and investigate the mechanisms surrounding this phenomenon. We also show that blocking CRVP379 protein with either RNAi or specific antisera inhibits DENV infection in Aedes aegypti. This work identifies a novel mosquito gene target for controlling DENV infection in mosquitoes that may also be used to develop broad preventative and therapeutic measures for multiple flaviviruses
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