573 research outputs found

    Universal Service in the United States: A Focus on Mobile Communications

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    The concept of universal service, providing affordable telecommunications to all citizens, has a long and changing history in the United States. Prior to the Telecommunications Act of 1996, efforts to achieve universal service were largely based on a complex web of implicit subsidies to basic landline local exchange residential service. The Act expanded and codified the concept of universal service and made the subsidies largely explicit. This Article evaluates the possible economic rationales for subsidizing voice communications and find them lacking. This Article argues that the weak rationale for subsidizing basic voice communications makes it critical that U.S. universal-service policy be competitively neutral with respect to firms and technologies in order to minimize distortions of market processes. However, past regulatory policies have favored wireline vis-A-vis mobile technologies. Moreover, four recent regulatory events threaten to perpetuate and exacerbate the asymmetric treatment of mobile technologies. The recent appointment of three new FCC commissioners may provide an opportunity for more economically rational and competitively neutral policy and funding mechanisms in the future

    Universal Service in the United States: A Focus on Mobile Communications

    Get PDF
    The concept of universal service, providing affordable telecommunications to all citizens, has a long and changing history in the United States. Prior to the Telecommunications Act of 1996, efforts to achieve universal service were largely based on a complex web of implicit subsidies to basic landline local exchange residential service. The Act expanded and codified the concept of universal service and made the subsidies largely explicit. This Article evaluates the possible economic rationales for subsidizing voice communications and find them lacking. This Article argues that the weak rationale for subsidizing basic voice communications makes it critical that U.S. universal-service policy be competitively neutral with respect to firms and technologies in order to minimize distortions of market processes. However, past regulatory policies have favored wireline vis-A-vis mobile technologies. Moreover, four recent regulatory events threaten to perpetuate and exacerbate the asymmetric treatment of mobile technologies. The recent appointment of three new FCC commissioners may provide an opportunity for more economically rational and competitively neutral policy and funding mechanisms in the future

    Systematic Analysis of Intracellular Trafficking Motifs Located within the Cytoplasmic Domain of Simian Immunodeficiency Virus Glycoprotein gp41

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    Previous studies have shown that truncation of the cytoplasmic-domain sequences of the simian immunodeficiency virus (SIV) envelope glycoprotein (Env) just prior to a potential intracellular-trafficking signal of the sequence YIHF can strongly increase Env protein expression on the cell surface, Env incorporation into virions and, at least in some contexts, virion infectivity. Here, all 12 potential intracellular-trafficking motifs (YXXΦ or LL/LI/IL) in the gp41 cytoplasmic domain (gp41CD) of SIVmac239 were analyzed by systematic mutagenesis. One single and 7 sequential combination mutants in this cytoplasmic domain were characterized. Cell-surface levels of Env were not significantly affected by any of the mutations. Most combination mutations resulted in moderate 3- to 8-fold increases in Env incorporation into virions. However, mutation of all 12 potential sites actually decreased Env incorporation into virions. Variant forms with 11 or 12 mutated sites exhibited 3-fold lower levels of inherent infectivity, while none of the other single or combination mutations that were studied significantly affected the inherent infectivity of SIVmac239. These minor effects of mutations in trafficking motifs form a stark contrast to the strong increases in cell-surface expression and Env incorporation which have previously been reported for large truncations of gp41CD. Surprisingly, mutation of potential trafficking motifs in gp41CD of SIVmac316, which differs by only one residue from gp41CD of SIVmac239, effectively recapitulated the increases in Env incorporation into virions observed with gp41CD truncations. Our results indicate that increases in Env surface expression and virion incorporation associated with truncation of SIVmac239 gp41CD are not fully explained by loss of consensus trafficking motifs

    RegenBase: a knowledge base of spinal cord injury biology for translational research.

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    Spinal cord injury (SCI) research is a data-rich field that aims to identify the biological mechanisms resulting in loss of function and mobility after SCI, as well as develop therapies that promote recovery after injury. SCI experimental methods, data and domain knowledge are locked in the largely unstructured text of scientific publications, making large scale integration with existing bioinformatics resources and subsequent analysis infeasible. The lack of standard reporting for experiment variables and results also makes experiment replicability a significant challenge. To address these challenges, we have developed RegenBase, a knowledge base of SCI biology. RegenBase integrates curated literature-sourced facts and experimental details, raw assay data profiling the effect of compounds on enzyme activity and cell growth, and structured SCI domain knowledge in the form of the first ontology for SCI, using Semantic Web representation languages and frameworks. RegenBase uses consistent identifier schemes and data representations that enable automated linking among RegenBase statements and also to other biological databases and electronic resources. By querying RegenBase, we have identified novel biological hypotheses linking the effects of perturbagens to observed behavioral outcomes after SCI. RegenBase is publicly available for browsing, querying and download.Database URL:http://regenbase.org

    Long-term and recent trends in hypertension awareness, treatment and control in twelve high-income countries: an analysis of 123 nationally representative surveys

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    Background: Antihypertensive medicines are effective in reducing adverse cardiovascular events. Our aim was to compare hypertension awareness, treatment and control, and how they have changed over time, in high-income countries. Methods: We used data on 526,336 participants aged 40-79 years in 123 national health examination surveys from 1976 to 2017 in twelve high-income countries: Australia, Canada, Finland, Germany, Ireland, Italy, Japan, New Zealand, South Korea, Spain, the UK, and the USA. We calculated the percent of participants with hypertension – defined as systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg or being on pharmacological treatment for hypertension – who were aware of their condition, who were treated, and whose hypertension was controlled (i.e. lower than 140/90 mmHg). Findings: Canada, South Korea, Australia and the UK have the lowest prevalence of hypertension, and Finland the highest. In the 1980s and early 1990s, treatment rates were at most 40% and control rates were below 25% in most countries and age-sex groups. Over time, hypertension awareness and treatment increased and control rate improved in all twelve countries, with South Korea and Germany experiencing the largest improvements. Most of the increase occurred in the 1990s and early-mid 2000s, having plateaued since in most countries. Canada, Germany, South Korea and the USA have the highest rates of awareness, treatment and control, while Finland, Ireland, Japan and Spain the lowest. Even in the best performing countries, treatment coverage was at most 80% and control rates were below 70%. Interpretation: Hypertension awareness, treatment and control have improved substantially in high-income countries since the 1980s and 1990s. However, control rates have plateaued in the past decade, at levels lower than those in high-quality hypertension programmes. There is substantial variation across countries in the rates of hypertension diagnosis, treatment an

    Spitzer, Near-Infrared, and Submillimeter Imaging of the Relatively Sparse Young Cluster, Lynds 988e

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    We present {\it Spitzer} images of the relatively sparse, low luminosity young cluster L988e, as well as complementary near-infrared (NIR) and submillimeter images of the region. The cluster is asymmetric, with the western region of the cluster embedded within the molecular cloud, and the slightly less dense eastern region to the east of, and on the edge of, the molecular cloud. With these data, as well as with extant Hα\alpha data of stars primarily found in the eastern region of the cluster, and a molecular 13^{13}CO gas emission map of the entire region, we investigate the distribution of forming young stars with respect to the cloud material, concentrating particularly on the differences and similarities between the exposed and embedded regions of the cluster. We also compare star formation in this region to that in denser, more luminous and more massive clusters already investigated in our comprehensive multi-wavelength study of young clusters within 1 kpc of the Sun.Comment: 21 pages, 6 tables, 13 figures. Full resolution figures at: http://astro.pas.rochester.edu/~tom/Preprints/L988e.pd

    MRI hip morphology is abnormal in unilateral DDH and increased lateral limbus thickness is associated with residual DDH at minimum 10-year follow-up.

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    PURPOSE The purpose of the study was to compare the post-reduction magnetic resonance imaging morphology for hips that developed residual acetabular dysplasia, hips without residual dysplasia, and uninvolved contralateral hips in patients with unilateral developmental dysplasia of the hip undergoing closed or open reduction and had a minimum 10-year follow-up. METHODS Retrospective study of patients with unilateral dysplasia of the hip who underwent open/closed hip reduction followed by post-reduction magnetic resonance imaging. Twenty-eight patients with a mean follow-up of 13 ± 3 years were included. In the treated hips, residual dysplasia was defined as subsequent surgery for residual acetabular dysplasia or for Severin grade > 2 at latest follow-up. On post-reduction, magnetic resonance imaging measurements were performed by two readers and compared between the hips with/without residual dysplasia and the contralateral uninvolved side. Magnetic resonance imaging measurements included acetabular version, coronal/ axial femoroacetabular distance, acetabular depth-width ratio, osseous/cartilaginous acetabular indices, and medial/lateral (limbus) cartilage thickness. RESULTS Fifteen (54%) and 13 (46%) hips were allocated to the "no residual dysplasia" group and to the "residual dysplasia" group, respectively. All eight magnetic resonance imaging parameters differed between hips with residual dysplasia and contralateral uninvolved hips (all p < 0.05). Six of eight parameters differed (all p < 0.05) between hips with and without residual dysplasia. Among these, increased limbus thickness had the largest effect (odds ratio = 12.5; p < 0.001) for increased likelihood of residual dysplasia. CONCLUSIONS We identified acetabular morphology and reduction quality parameters that can be reliably measured on the post-reduction magnetic resonance imaging to facilitate the differentiation between hips that develop with/without residual acetabular dysplasia at 10 years postoperatively. LEVEL OF EVIDENCE level III, prognostic case-control study

    Fixed-Parameter Algorithms in Analysis of Heuristics for Extracting Networks in Linear Programs

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    We consider the problem of extracting a maximum-size reflected network in a linear program. This problem has been studied before and a state-of-the-art SGA heuristic with two variations have been proposed. In this paper we apply a new approach to evaluate the quality of SGA\@. In particular, we solve majority of the instances in the testbed to optimality using a new fixed-parameter algorithm, i.e., an algorithm whose runtime is polynomial in the input size but exponential in terms of an additional parameter associated with the given problem. This analysis allows us to conclude that the the existing SGA heuristic, in fact, produces solutions of a very high quality and often reaches the optimal objective values. However, SGA contain two components which leave some space for improvement: building of a spanning tree and searching for an independent set in a graph. In the hope of obtaining even better heuristic, we tried to replace both of these components with some equivalent algorithms. We tried to use a fixed-parameter algorithm instead of a greedy one for searching of an independent set. But even the exact solution of this subproblem improved the whole heuristic insignificantly. Hence, the crucial part of SGA is building of a spanning tree. We tried three different algorithms, and it appears that the Depth-First search is clearly superior to the other ones in building of the spanning tree for SGA. Thereby, by application of fixed-parameter algorithms, we managed to check that the existing SGA heuristic is of a high quality and selected the component which required an improvement. This allowed us to intensify the research in a proper direction which yielded a superior variation of SGA

    A century of trends in adult human height

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    Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3–19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8–144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries
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