361 research outputs found
The Pro-Trade Effect of Immigration on American Exports During the Late Nineteenth and Early Twentieth Centuries
The belief that immigrants generate beneficial externalities in their host countries, specifically
in the form of an increased opportunity and ability of firms to expand their foreign trade, has
recently been challenged by George Borjas in Heaven?s Door (1999, p. 97) as having no
empirical support. Borjas? assertion ignores several recent papers that provide precisely that
evidence of a powerful pro-trade effect of international migration. Here we extend that body
of evidence by looking to history. We show that immigration, primarily from Europe between
1870 and 1910, had an important pro-trade effect on American exports. Our data set spans
the exports of 44 commodities to 17 countries observed at 5 year intervals. We use a
modified gravity model to examine the migrant stock-export relationship and find that United
States exports to a country were positively related to the size of the migrant stock of
immigrants from that country. The estimated strength of the effect varied across ?Old?
Europe, ?New? Europe, and non-Europe groupings of the trading partner countries. Exports
were also found to have been greater to English-speaking countries, and to countries with
per capita incomes similar to the United States. This relative per capita income effect became
stronger during the latter part of the period, whereas the migrant stock effect diminished after
1885
Is increased hepatitis C virus case-finding combined with current or 8-week to 12-week direct-acting antiviral therapy cost-effective in UK prisons? A prevention benefit analysis
UNLABELLED: Prisoners have a high prevalence of hepatitis C virus (HCV), but case-finding may not have been cost-effective because treatment often exceeded average prison stay combined with a lack of continuity of care. We assessed the cost-effectiveness of increased HCV case-finding and treatment in UK prisons using short-course therapies. A dynamic HCV transmission model assesses the cost-effectiveness of doubling HCV case-finding (achieved through introducing opt-out HCV testing in UK pilot prisons) and increasing treatment in UK prisons compared to status quo voluntary risk-based testing (6% prison entrants/year), using currently recommended therapies (8-24 weeks) or interferon (IFN)-free direct-acting antivirals (DAAs; 8-12 weeks, 95% sustained virological response, Ā£3300/week). Costs (British pounds, Ā£) and health utilities (quality-adjusted life years) were used to calculate mean incremental cost-effectiveness ratios (ICERs). We assumed 56% referral and 2.5%/25% of referred people who inject drugs (PWID)/ex-PWID treated within 2 months of diagnosis in prison. PWID and ex-PWID or non-PWID are in prison an average 4 and 8 months, respectively. Doubling prison testing rates with existing treatments produces a mean ICER of Ā£19,850/quality-adjusted life years gained compared to current testing/treatment and is 45% likely to be cost-effective under a Ā£20,000 willingness-to-pay threshold. Switching to 8-week to 12-week IFN-free DAAs in prisons could increase cost-effectiveness (ICER Ā£15,090/quality-adjusted life years gained). Excluding prevention benefit decreases cost-effectiveness. If >10% referred PWID are treated in prison (2.5% base case), either treatment could be highly cost-effective (ICER<Ā£13,000). HCV case-finding and IFN-free DAAs could be highly cost-effective if DAA cost is 10% lower or with 8 weeks' duration. CONCLUSIONS: Increased HCV testing in UK prisons (such as through opt-out testing) is borderline cost-effective compared to status quo voluntary risk-based testing under a Ā£20,000 willingness to pay with current treatments but likely to be cost-effective if short-course IFN-free DAAs are used and could be highly cost-effective if PWID treatment rates were increased. (Hepatology 2016;63:1796-1808)
Assessment of arsenic status and distribution in Usangu agro-ecosystem-Tanzania.
The research article published by Elsevier Ltd., 2021This study was conducted to assess arsenic (As) status and distribution in Usangu agroecosystem-Tanzania, including three land use. About 198 soil samples were collected in ten irrigation schemes in three land uses. Total and bioavailable As were determined by acid digestion (Aqua regia (AQ)) and Mehlich 3 method (M3) to estimate status, distribution and bioavailability. Arsenic concentration were variable among land use and irrigation schemes where total arsenic ranged 567.74-2909.84Ā Ī¼g/kg and bioavailable As ranged 26.17-712.37Ā Ī¼g/kg. About 12-16% of total arsenic were available for plant uptake. Approximately 86.53% of studied agricultural soils had total As concentration above Tanzania maximum allowable limit. Bioavailable As were lower compared to total As and were within the acceptable threshold. Total arsenic concentration were variable among schemes and higher values were observed in schemes which are highly intensified and mechanized. Thus, this study provides essential site specific preliminary baseline information for As status and distribution in agricultural soils to initiate monitoring and management strategies for increased land productivity and environmental safety
The effects of mesoscale oceanāatmosphere coupling on the large-scale ocean circulation
Author Posting. Ā© American Meteorological Society, 2009. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 22 (2009): 4066ā4082, doi:10.1175/2009JCLI2629.1.Small-scale variation in wind stress due to oceanāatmosphere interaction within the atmospheric boundary layer alters the temporal and spatial scale of Ekman pumping driving the double-gyre circulation of the ocean. A high-resolution quasigeostrophic (QG) ocean model, coupled to a dynamic atmospheric mixed layer, is used to demonstrate that, despite the small spatial scale of the Ekman-pumping anomalies, this phenomenon significantly modifies the large-scale ocean circulation. The primary effect is to decrease the strength of the nonlinear component of the gyre circulation by approximately 30%ā40%. This result is due to the highest transient Ekman-pumping anomalies destabilizing the flow in a dynamically sensitive region close to the western boundary current separation. The instability of the jet produces a flux of potential vorticity between the two gyres that acts to weaken both gyres.AH and WD were supported
by an ARC Linkage International Grant (LX0668781). WD was also supported by NSF Grants OCE 0424227
and OCE 0550139. Funding for PB was provided by
NSF Grants OCE 0344094 and OCE 0725796 and by the
research grant from the Newton Trust of the University
of Cambridge. SK was supported by U.S. DOE Grant
DE-FG02ā02ER63413 and NASA Grant NNG-06-
AG66G-1
Performance of Monolayer Graphene Nanomechanical Resonators with Electrical Readout
The enormous stiffness and low density of graphene make it an ideal material
for nanoelectromechanical (NEMS) applications. We demonstrate fabrication and
electrical readout of monolayer graphene resonators, and test their response to
changes in mass and temperature. The devices show resonances in the MHz range.
The strong dependence of the resonant frequency on applied gate voltage can be
fit to a membrane model, which yields the mass density and built-in strain.
Upon removal and addition of mass, we observe changes in both the density and
the strain, indicating that adsorbates impart tension to the graphene. Upon
cooling, the frequency increases; the shift rate can be used to measure the
unusual negative thermal expansion coefficient of graphene. The quality factor
increases with decreasing temperature, reaching ~10,000 at 5 K. By establishing
many of the basic attributes of monolayer graphene resonators, these studies
lay the groundwork for applications, including high-sensitivity mass detectors
The COVID-19 Pandemic and Physical Activity
The SARS-CoV-2-caused COVID-19 pandemic has resulted in a devastating threat to human society in terms of health, economy, and lifestyle. Although the virus usually first invades and infects the lung and respiratory track tissue, in extreme cases, almost all major organs in the body are now known to be negatively impacted often leading to severe systemic failure in some people. Unfortunately, there is currently no effective treatment for this disease. Pre-existing pathological conditions or comorbidities such as age are a major reason for premature death and increased morbidity and mortality. The immobilization due to hospitalization and bed rest and the physical inactivity due to sustained quarantine and social distancing can downregulate the ability of organs systems to resist to viral infection and increase the risk of damage to the immune, respiratory, cardiovascular, musculoskeletal systems and the brain. The cellular mechanisms and danger of this "second wave" effect of COVID-19 to the human body, along with the effects of aging, proper nutrition, and regular physical activity, are reviewed in this editorial article
Academic neurosurgery in the UK: present and future directions.
Academic neurosurgery encompasses basic science and clinical research efforts to better understand and treat diseases of relevance to neurosurgical practice, with the overall aim of improving treatment and outcome for patients. In this article, we provide an overview of the current and future directions of British academic neurosurgery. Training pathways are considered together with personal accounts of experiences of structured integrated clinical academic training and unstructured academic training. Life as an academic consultant is also described. Funding is explored, for the specialty as a whole and at the individual level. UK academic neurosurgical organisations are highlighted. Finally, the UK's international standing is considered
Gasless Laparoscopic Surgery for Minimally Invasive Surgery in Low-Resource Settings: Methods for Evaluating Surgical Field of View and Abdominal Wall Lift Force
Funder: Translate MedTec
Variants in interferon-alpha pathway genes and response to pegylated interferon-Alpha2a plus ribavirin for treatment of chronic hepatitis C virus infection in the hepatitis C antiviral long-term treatment against cirrhosis trial
Combination treatment with pegylated-interferon-alpha (PEG IFN-Ī) and ribavirin, the current recommended therapy for chronic hepatitis C virus (HCV) infection, results in a sustained virological response (SVR) in only about half of patients. Because genes involved in the interferon-alpha pathway may affect antiviral responses, we analyzed the relationship between variants in these genes and SVR among participants in the Hepatitis C Antiviral Long-Term treatment Against Cirrhosis (HALT-C) trial. Patients had advanced chronic hepatitis C that had previously failed to respond to interferon-based treatment. Participants were treated with peginterferon-Ī2a and ribavirin during the trial. Subjects with undetectable HCV RNA at week 72 were considered to have had an SVR. Subjects with detectable HCV RNA at week 20 were considered nonresponders. We used TaqMan assays to genotype 56 polymorphisms found in 13 genes in the interferon-alpha pathway. This analysis compares genotypes for participants with an SVR to nonresponders. The primary analysis was restricted to European American participants because a priori statistical power was low among the small number (n = 131) of African American patients. We used logistic regression to control the effect of other variables that are associated with treatment response. Among 581 European American patients, SVR was associated with IFNAR1 IVS1-22G (adjusted odds ratio, 0.57; P = 0.02); IFNAR2 Ex2-33C (adjusted odds ratio, 2.09; P = 0.02); JAK1 IVS22+112T (adjusted odds ratio, 1.66; P = 0.04); and ADAR Ex9+14A (adjusted odds ratio, 1.67; P = 0.03). For the TYK2 -2256A promoter region variant, a borderline association was present among European American participants (OR, 1.51; P = 0.05) and a strong relationship among African American patients; all 10 with SVR who were genotyped for TYK2 -2256 carried the A variant compared with 68 of 120 (57%) nonresponders ( P = 0.006). Conclusion: Genetic polymorphisms in the interferon-Ī pathway may affect responses to antiviral therapy of chronic hepatitis C. (H EPATOLOGY 2009.)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63061/1/22877_ftp.pd
Targeted next-generation sequencing of DNA regions proximal to a conserved GXGXXG signaling motif enables systematic discovery of tyrosine kinase fusions in cancer
Tyrosine kinase (TK) fusions are attractive drug targets in cancers. However, rapid identification of these lesions has been hampered by experimental limitations. Our in silico analysis of known cancer-derived TK fusions revealed that most breakpoints occur within a defined region upstream of a conserved GXGXXG kinase motif. We therefore designed a novel DNA-based targeted sequencing approach to screen systematically for fusions within the 90 human TKs; it should detect 92% of known TK fusions. We deliberately paired āin-solutionā DNA capture with 454 sequencing to minimize starting material requirements, take advantage of long sequence reads, and facilitate mapping of fusions. To validate this platform, we analyzed genomic DNA from thyroid cancer cells (TPC-1) and leukemia cells (KG-1) with fusions known only at the mRNA level. We readily identified for the first time the genomic fusion sequences of CCDC6-RET in TPC-1 cells and FGFR1OP2-FGFR1 in KG-1 cells. These data demonstrate the feasibility of this approach to identify TK fusions across multiple human cancers in a high-throughput, unbiased manner. This method is distinct from other similar efforts, because it focuses specifically on targets with therapeutic potential, uses only 1.5āĀµg of DNA, and circumvents the need for complex computational sequence analysis
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