3,712 research outputs found
(Re)modeling the Narrative: Communication Networks, Petitionary Texts, and the 13th Century Prosopography
Studies that apply Social Network Analysis (SNA) to historical documents and literary texts are becoming more reflective of the innovations and developments in digital medieval studies. Historical SNA studies conducted by Hammond (2016) looks at family trees in medieval Scotland to create a network. Similarly, Geggel (2018), builds a literary
network using Irish and Viking texts, demonstrating a shift in medieval studies as they converge with network theory.
However, none of these studies focus on historical documents or their contributions to paleography. In this project I
employ SNA to examine the reign of Edward I (1272-1307), both in terms his place in English history and his impact on
historical communication networks. Using petitions as historical evidence, I analyze smaller conversations occurring
in England, looking at whether these events did, in fact, impact life in Western Europe. The data extracted from these
minor historical documents are used to construct visualizations representing prosopographies - or collective narratives - shaped by English communication networks. The source material for my current research begins with a sample
of 413 open-source digitized documents available from the British National Archives’ Special Collection 8. I argue that
this methodology can give historians a better sense of the past. The results of this study reveal trends in 13th century
communication networks, but, more importantly, provide the framework for a working model that future research in
historical Social Network Analysis can implement
Stable low-level expression of p21(WAF1/CIP1 )in A549 human bronchogenic carcinoma cell line-derived clones down-regulates E2F1 mRNA and restores cell proliferation control
BACKGROUND: Deregulated cell cycle progression and loss of proliferation control are key properties of malignant cells. In previous studies, an interactive transcript abundance index (ITAI) comprising three cell cycle control genes, [MYC × E2F1]/p21 accurately distinguished normal from malignant bronchial epithelial cells (BEC), using a cut-off threshold of 7,000. This cut-off is represented by a line with a slope of 7,000 on a bivariate plot of p21 versus [MYC × E2F1], with malignant BEC above the line and normal BEC below the line. This study was an effort to better quantify, at the transcript abundance level, the difference between normal and malignant BEC. The hypothesis was tested that experimental elevation of p21 in a malignant BEC line would decrease the value of the [MYC × E2F1]/p21 ITAI to a level below this line, resulting in loss of immortality and limited cell population doubling capacity. In order to test the hypothesis, a p21 expression vector was transfected into the A549 human bronchogenic carcinoma cell line, which has low constitutive p21 TA expression relative to normal BEC. RESULTS: Following transfection of p21, four A549/p21 clones with stable two-fold up-regulated p21 expression were isolated and expanded. For each clone, the increase in p21 transcript abundance (TA) was associated with increased total p21 protein level, more than 5-fold reduction in E2F1 TA, and 10-fold reduction in the [MYC × E2F1]/p21 ITAI to a value below the cut-off threshold. These changes in regulation of cell cycle control genes were associated with restoration of cell proliferation control. Specifically, each transfectant was capable of only 15 population doublings compared with unlimited population doublings for parental A549. This change was associated with an approximate 2-fold increase in population doubling time to 38.4 hours (from 22.3 hrs), resumption of contact-inhibition, and reduced dividing cell fraction as measured by flow cytometric DNA analysis. CONCLUSION: These results, likely due to increased p21-mediated down-regulation of E2F1 TA at the G1/S phase transition, are consistent with our hypothesis. Specifically, they provide experimental confirmation that a line with slope of 7,000 on the p21 versus [MYC × E2F1] bivariate plot quantifies the difference between normal and malignant BEC at the level of transcript abundance
Radiation measurements from polar and geosynchronous satellites
June 1978.Includes bibliographical references.This is the Annual report for period 1 November 1976-31 October 1977 and the Final report, 10 October 1970-31 July 1978 for National Aeronatuics and Space Administratin grant NGR-06-002-102.National Aeronatuics and Space Administratin grant NGR-06-002-10
Clinical outcomes of stents versus balloon angioplasty in non-acute coronary artery disease: A meta-analysis of randomized controlled trials
Aims To evaluate whether stents as compared to balloon angioplasty reduce mortality in patients with non-acute coronary artery disease. Methods and results We identified randomized controlled trials comparing stents to balloon angioplasty for the treatment of non-acute coronary artery disease by searching major medical databases from 1979 to March 2002. Two independent reviewers selected and extracted data from trials that had to report data on death and myocardial infarction. Nineteen trials, with a total of 8004 patients, fulfilled our inclusion criteria. For 1000 patients treated with stents rather than balloon angioplasty, 3 (95% CI 0-6), 5 (95% CI 0-9), and 6 (95% CI -1-12) additional lives were saved at 30 days, 6 and 12 months. At 12 months, for 1000 patients treated with stents rather than balloon angioplasty 46 (95% CI 25-66) additional target vessel revascularizations were avoided, but 25 (95% CI 15-34) additional bleeding complications with need for blood transfusion or surgical intervention occurred. In sensitivity analysis 11 (95% CI 2-20) and 2 (95% CI -4-7) deaths were avoided per 1000 patients treated with stents rather than PTCA in trials that routinely used compared to trials that did not use glycoprotein IIb/IIIa inhibitors. Conclusion In non-acute coronary disease stents may reduce overall mortality, but this benefit seems to be limited to stents used in conjunction with glycoprotein IIb/IIIa inhibitors. Stents compared to PTCA reduce target vessel revascularizations, but increase the risk of bleeding complication
Variation in transcriptional regulation of cyclin dependent kinase inhibitor p21(waf1/cip1 )among human bronchogenic carcinomas
BACKGROUND: Cell proliferation control depends in part on the carefully ordered regulation of transcription factors. The p53 homolog p73, contributes to this control by directly upregulating the cyclin dependent kinase inhibitor, p21(waf1/cip1). E2F1, an inducer of cell proliferation, directly upregulates p73 and in some systems upregulates p21 directly. Because of its central role in controlling cell proliferation, upregulation of p21 has been explored as a modality for treating bronchogenic carcinoma (BC). Improved understanding of p21 transcriptional regulation will facilitate identification of BC tissues that are responsive to p21-directed therapies. Toward this goal, we investigated the role that E2F1 and p73 each play in the transcriptional regulation of p21. RESULTS: Among BC samples (N = 21) p21 transcript abundance (TA) levels varied over two orders of magnitude with values ranging from 400 to 120,000 (in units of molecules/10(6 )molecules β-actin). The p21 values in many BC were high compared to those observed in normal bronchial epithelial cells (BEC) (N = 18). Among all BC samples, there was no correlation between E2F1 and p21 TA but there was positive correlation between E2F1 and p73α (p < 0.001) TA. Among BC cell lines with inactivated p53 and wild type p73 (N = 7) there was positive correlation between p73α and p21 TA (p < 0.05). Additionally, in a BC cell line in which both p53 and p73 were inactivated (H1155), E2F1 TA level was high (50,000), but p21 TA level was low (470). Transiently expressed exogenous p73α in the BC cell line Calu-1, was associated with a significant (p < 0.05) 90% increase in p21 TA and a 20% reduction in E2F1 TA. siRNA mediated reduction of p73 TA in the N417 BC cell line was associated with a significant reduction in p21 TA level (p < 0.01). CONCLUSION: p21 TA levels vary considerably among BC patients which may be attributable to 1) genetic alterations in Rb and p53 and 2) variation in TA levels of upstream transcription factors E2F1 and p73. Here we provide evidence that p73 upregulates p21 TA in BC tissues and upregulated p21 TA may result from E2F1 upregulation of p73 but not from E2F1 directly
An ocean coupling potential intensity index for tropical cyclones
© American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 40 (2013): 1878–1882, doi:10.1002/grl.50091.Timely and accurate forecasts of tropical cyclones (TCs, i.e., hurricanes and typhoons) are of great importance for risk mitigation. Although in the past two decades there has been steady improvement in track prediction, improvement on intensity prediction is still highly challenging. Cooling of the upper ocean by TC-induced mixing is an important process that impacts TC intensity. Based on detail in situ air-deployed ocean and atmospheric measurement pairs collected during the Impact of Typhoons on the Ocean in the Pacific (ITOP) field campaign, we modify the widely used Sea Surface Temperature Potential Intensity (SST_PI) index by including information from the subsurface ocean temperature profile to form a new Ocean coupling Potential Intensity (OC_PI) index. Using OC_PI as a TC maximum intensity predictor and applied to a 14 year (1998–2011) western North Pacific TC archive, OC_PI reduces SST_PI-based overestimation of archived maximum intensity by more than 50% and increases the correlation of maximum intensity estimation from r2 = 0.08 to 0.31. For slow-moving TCs that cause the greatest cooling, r2 increases to 0.56 and the root-mean square error in maximum intensity is 11 m s−1. As OC_PI can more realistically characterize the ocean contribution to TC intensity, it thus serves as an effective new index to improve estimation and prediction of TC maximum intensity.This work is supported by Taiwan’s National
Science Council and National Taiwan University (grant numbers: NSC 101-
2111-M-002-002-MY2; NSC 101-2628-M-002-001-MY4; 102R7803) and
US Office of Naval Research (ONR) under the Impact of Typhoons on
Pacific (ITOP) program. PB’s support is provided by ONR under
PE 0601153N through NRL Contract N00173-10-C-6019
Landowners' perceptions of risk in grassland management: Woody plant encroachment and prescribed fire
Ecologists recognize that fire and herbivory are essential to maintaining habitat quality in grassland ecosystems. Prescribed fire and grazing are typically used on public reserves to increase biodiversity, improve grassland productivity, and control encroachment of woody plants. However, these tools, particularly prescribed fire, have not been widely adopted by private landowners. Fire suppression and prescribed fire are strategies that present competing risks to owners who make management decisions. We explore landowner perceptions of risk associated with (1) eastern redcedar (Juniperus virginiana) encroachment, and (2) the use of prescribed fire to control woody species in the Grand River Grasslands of Iowa and Missouri, USA. We found that although mapping data of eastern redcedar in this region showed substantial encroachment over the past three decades, concept mapping of landowner beliefs and in-person interviews of local community leaders revealed that perceived risks associated with prescribed fire often outweighed those associated with loss of forage and grassland habitats.Peer reviewedNatural Resource Ecology and Managemen
Clinical Outcomes of Primary Stenting versus Balloon Angioplasty in Patients with Myocardial Infarction: A Meta-analysis of Randomized Controlled Trials
PURPOSE: To examine whether primary stenting as compared with primary balloon angioplasty reduces clinical outcomes in patients with myocardial infarction. METHODS: Major medical databases from 1979 to March 2002 were searched for randomized controlled trials that compared primary stenting with balloon angioplasty in patients with myocardial infarction. Two independent reviewers selected and extracted data from identified trials. The outcomes were mortality at 30 days, 6 months, and 12 months; recurrent events; and bleeding. RESULTS: Nine trials with a total of 4433 patients fulfilled the inclusion criteria. The odds ratios for mortality after stenting as compared with balloon angioplasty were 1.17 (95% confidence interval [CI]: 0.78 to 1.74) at 30 days, 1.07 (95% CI: 0.76 to 1.52) at 6 months, and 1.09 (95% CI: 0.80 to 1.50) at 12 months (P for heterogeneity Ͼ0.1 for each comparison). The odds ratios for reinfarction after stenting as compared with balloon angioplasty were 0.52 (95% CI: 0.31 to 0.87) at 30 days, 0.67 (95% CI: 0.45 to 1.00) at 6 months, and 0.67 (95% CI: 0.45 to 0.99) at 12 months; for target vessel revascularization, they were 0.46 (95% CI: 0.34 to 0.61) at 30 days, 0.42 (95% CI: 0.35 to 0.51) at 6 months, and 0.48 (95% CI: 0.39 to 0.59) at 12 months (P for heterogeneity Ͼ0.1 for all estimates with the exception of reinfarction at 12 months where P Ï 0.08). The odds ratio for postinterventional bleeding complications after stenting as compared with balloon angioplasty was 1.34 (95% CI: 0.95 to 1.88; P for heterogeneity Ͼ0.1). CONCLUSION: Compared with balloon angioplasty, primary stenting is not associated with lower mortality, but is associated with a lower risk of reinfarction and target vessel revascularization. Am J Med. 2004;116:253-262. ©2004 by Excerpta Medica Inc. I n patients with myocardial infarction, balloon angioplasty reduces short-term death, nonfatal myocardial infarction, and stroke when compared with thrombolytic reperfusion (1). Still, the clinical efficacy of balloon angioplasty is limited by the development of late restenosis in up to 50% of patients, and by recurrent myocardial infarction in 3% to 5% of patients (2-5). Primary stenting may offer additional benefits. However, a recent meta-analysis of clinical trials found no difference in mortality and reinfarction rates among patients undergoing stenting or balloon angioplasty (6). We conducted a meta-analysis based on published and unpublished trial data to investigate whether primary stenting as compared with balloon angioplasty reduces mortality, recurrent events, and the risk of bleeding in patients with myocardial infarction. METHODS Data Search and Trial Selection We searched MEDLINE, EMBASE, Pascal, Index Medicus, the Cochrane Library, and abstracts from cardiology conferences from 1979 to March 2002 to identify all randomized controlled trials that compared primary stenting with balloon angioplasty in patients with myocardial infarction. We used the following search terms: angioplasty transluminal percutaneous coronary, stents, randomized controlled trials, clinical trials, coronary artery dilatation, transluminal coronary angioplasty, and random. We also searched all references of relevant articles for additional trials. If necessary, authors of identified trials were contacted for additional information
COVID-19 in Sub-Saharan Africa: Impacts on land, governance, and livelihoods
This paper focuses on the impacts of COVID-19 on livelihoods, land access and governance in rural and peri urban selected areas of Sub-Saharan Africa. Crises are usually expected to be worse for citizens in developing countries since most of their economic activities are in the informal sector, and access to the social protection programs is often limited and exclusionary. Those vulnerable and marginalized are often those who are hit the hardest and who struggle the most to recover after crises. The COVID-19 pandemic is no exception. Extended lockdowns have put livelihoods under stress, underlying patterns of fragile livelihoods and inequality. There are also particular vulnerabilities with regards to land access and livelihoods of vulnerable populations. Our case studies document how the pandemic has affected livelihoods through several mechanisms relating to land access, including distress sales due to economic hardships and exacerbating land conflicts due to increased pressure on land and increasing trends of urban-to-rural migration. We reflect on how households act and react when faced with shocks and how this affects not only their current access to livelihood assets but might undermine their options for the future. In addition, a range of other effects were identified in our case studies that we expect to negatively impact livelihood recovery
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