898 research outputs found

    Legislating the Tower of Babel: International Restrictions on Internet Content and the Marketplace of Ideas

    Get PDF
    The First Amendment to the U.S. Constitution protects the expression of diverse viewpoints in virtually any medium. Nevertheless, the modern novelty of borderless communication via the Internet strains our ideal of keeping government out of the business of regulating speech. This Note reveals the conflict between the First Amendment\u27s national protections and the Internet\u27s lack of national boundaries, while also arguing for international intervention for the protection of free speech. This Author articulates the real danger of watered-down speech unless both the FCC and the international community provide regulations and harmonized international standards for online content that reflect First Amendment protections

    Legislating the Tower of Babel: International Restrictions on Internet Content and the Marketplace of Ideas

    Get PDF
    The First Amendment to the U.S. Constitution protects the expression of diverse viewpoints in virtually any medium. Nevertheless, the modern novelty of borderless communication via the Internet strains our ideal of keeping government out of the business of regulating speech. This Note reveals the conflict between the First Amendment\u27s national protections and the Internet\u27s lack of national boundaries, while also arguing for international intervention for the protection of free speech. This Author articulates the real danger of watered-down speech unless both the FCC and the international community provide regulations and harmonized international standards for online content that reflect First Amendment protections

    Increased Risk for Aplastic Anemia and Myelodysplastic Syndrome in Individuals Lacking Glutathione S-Transferase Genes

    Get PDF
    BACKGROUND: Aplastic anemia (AA) and myelodysplastic syndrome (MDS) are marrow failure states that may be associated with chromosomal instability. An absence of the glutathione S-transferase (GST) enzyme may genetically predispose individuals to AA or MDS. PROCEDURE AND RESULTS: To test this hypothesis, we determined the GSTM1 and GSTT1 genotypes in a total of 196 patients using multiplex PCR. The GSTT1 null genotype was found to be overrepresented in Caucasian, Asian, and Hispanic patients with either AA or MDS. We confirmed a difference in the expected frequency of the GSTM1 null genotype in Caucasian MDS patients. The double null GSTM1/GSTT1 genotype was also overrepresented in Caucasian AA and MDS patients. In our population, 26% of AA patients and 40% of MDS patients had a chromosomal abnormality identified by karyotype or FISH analyses for chromosomes 7 and 8. Patients with AA and the GSTT1 null genotype had an increased frequency of chromosomal abnormalities (P = 0.003). CONCLUSION: There seems to be an increased risk for AA and MDS in individuals lacking GSTT1 or both GSTM1/GSTT1

    Catchment land use effects on fluxes and concentrations of organic and inorganic nitrogen in streams

    Get PDF
    We present annual downstream fluxes and spatial variation in concentrations of dissolved inorganic nitrogen (NH4+ and NO3−) and dissolved organic nitrogen (DON) in two adjacent Scottish catchments with contrasting land use (agricultural grassland vs. semi-natural moorland). Inter- and intra-catchment variation in N species and the relation to spatial differences in agricultural land use were studied by determining catchment N input through agricultural activities at the field scale and atmospheric inputs at a 25 m grid resolution. The average agricultural N input of 52 kg N ha−1 yr−1 to the grassland catchment was more than 4 times higher than the input of 12 kg N ha−1 yr−1 to the moorland catchment, supplemented by 12.3 and 8.2 kg N ha−1 yr−1 through atmospheric deposition, respectively. The grassland catchment was associated with an annual downstream total dissolved nitrogen (TDN) flux of 14.4 kg N ha−1 yr−1, which was 66% higher than the flux of 8.7 kg ha−1 yr−1 from the moorland catchment. This difference was largely due to the NO3− flux being one order of magnitude higher in the grassland catchment. Dissolved organic N fluxes were similar for the two catchments (7.0 kg ha−1 yr−1) with DON contributing 49% to the TDN flux in the grassland compared with 81% in the moorland catchment. The results highlight the importance of diffuse agricultural N inputs to stream NO3− concentrations and the importance of quantifying all the major aquatic N species for developing a better understanding of N transformations and transport in the atmosphere-soil-water system

    Phylogenetic analyses reveal multiple new stem-boring Tetramesa taxa (Hymenoptera: Eurytomidae): implications for the biological control of invasive African grasses

    Get PDF
    Many native South African grass species have become invasive elsewhere in the world. The application of biological control to invasive grasses has been approached with trepidation in the past, primarily due to concerns of a perceived lack of host specific herbivores. This has changed in recent times, and grasses are now considered suitable candidates. The Tetramesa Walker genus (Hymenoptera: Eurytomidae) has been found to contain species that are largely host specific to a particular grass species, or complex of closely related congeners. Very little taxonomic work exists for Tetramesa in the southern hemisphere, and the lack of morphological variability between many Tetramesa species has made identification difficult. This limits the ability to assess the genus for potential biological control agents. Species delimitation analyses indicated 16 putative novel southern African Tetramesa taxa. Ten of these were putative Tetramesa associated with Eragrostis curvula (Schrad.) Nees and Sporobolus pyramidalis Beauv. and S. natalensis Steud., which are alien invasive weeds in Australia. Of these ten Tetramesa taxa, eight were only found on a single host plant, while two taxa were associated with multiple species in a single grass genus. The Tetramesa spp. on S. pyramidalis and S. africanus were deemed suitably host-specific to be used as biological control agents. Field host range data for the Tetramesa species on E. curvula revealed that the wasp may not be suitably host specific for use as a biological control agent. However, further host specificity testing on non-target native Australian species is required

    Growth of oriented C11b MoSi2 bicrystals using a modified Czochralski technique

    Get PDF
    Oriented bicrystals of pure C11b MoSi2 have been grown in a tri-arc furnace using the Czochralski technique. Two single crystal seeds were used to initiate the growth. Each seed had the orientation intended for one of the grains of the bicrystals, which resulted in a 60° twist boundary on the (110) plane. Seeds were attached to a water-cooled seed rod, which was pulled at 120 mm/h with the seed rod rotating at 45 rpm. The water- cooled copper hearth was counter-rotated at 160 rpm. Asymmetric growth ridges associated with each seed crystal were observed during growth and confirmed the existence of a bicrystal. It was also found that careful alignment of the seeds was needed to keep the grain boundary from growing out of the boule. The resulting boundary was characterized by imaging and crystallographic techniques in a scanning electron microscope. The boundary was found to be fairly sharp and the misorientation between the grains remained within 2° from the disorientation between the seeds

    Field-based ecological studies to assess prospective biological control agents for invasive alien plants: An example from giant rat's tail grass

    Get PDF
    Biological control (biocontrol) of invasive alien plants is a widely utilised weed management tool. Prospective biocontrol agents are typically assessed through host specificity testing and pre-release efficacy studies performed in quarantine. However, rearing of the potential biocontrol agents and/or test plants is often difficult or impossible under quarantine conditions. Moreover, practitioners may attain laboratory artefacts in quarantine, which may result in the potential agent being needlessly rejected. Field-based studies in the weed's indigenous distribution could overcome these issues

    Grasses as suitable targets for classical weed biological control

    Get PDF
    Grasses are amongst the most abundant and environmentally damaging invasive weeds worldwide. Biological control is frequently employed as a sustainable and cost-effective management strategy for many weeds. However, grasses have not been actively pursued as targets for classical weed biological control due to a perceived lack of sufficiently specialised and damaging natural enemies to use as biological control agents. There are also concerns that the risk posed to economically important crop/pasture species and closely-related native species is too great to consider implementing biological control for invasive grasses. In this paper, we review the literature and demonstrate that grasses can possess suitably host-specific and damaging natural enemies to warrant consideration as potential biological control agents. The risk of grass biological control is no greater than for other weedy taxa if practitioners follow appropriately rigorous risk assessments protocols

    Contractility parameters of human -cardiac myosin with the hypertrophic cardiomyopathy mutation R403Q show loss of motor function

    Get PDF
    Hypertrophic cardiomyopathy (HCM) is the most frequently occurring inherited cardiovascular disease. It is caused by mutations in genes encoding the force-generating machinery of the cardiac sarcomere, including human ?-cardiac myosin. We present a detailed characterization of the most debated HCM-causing mutation in human ?-cardiac myosin, R403Q. Despite numerous studies, most performed with nonhuman or noncardiac myosin, there is no consensus about the mechanism of action of this mutation on the function of the enzyme. We use recombinant human ?-cardiac myosin and new methodologies to characterize in vitro contractility parameters of the R403Q myosin compared to wild type. We extend our studies beyond pure actin filaments to include the interaction of myosin with regulated actin filaments containing tropomyosin and troponin. We find that, with pure actin, the intrinsic force generated by R403Q is ~15% lower than that generated by wild type. The unloaded velocity is, however, ~10% higher for R403Q myosin, resulting in a load-dependent velocity curve that has the characteristics of lower contractility at higher external loads compared to wild type. With regulated actin filaments, there is no increase in the unloaded velocity and the contractility of the R403Q myosin is lower than that of wild type at all loads. Unlike that with pure actin, the actin-activated adenosine triphosphatase activity for R403Q myosin with Ca2+-regulated actin filaments is ~30% lower than that for wild type, predicting a lower unloaded duty ratio of the motor. Overall, the contractility parameters studied fit with a loss of human ?-cardiac myosin contractility as a result of the R403Q mutation
    • …
    corecore