222 results on '"Griffiths, Robert"'
Search Results
2. Rewriting cricket history
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Griffiths, Robert and Whale, Stephen
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- 2008
Catalog
3. Diagnosis of previous exposure to asbestos
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Griffiths, Robert
- Published
- 1998
4. Identifying Primary Care Pathways from Quality of Care to Outcomes and Satisfaction Using Structural Equation Modeling
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Ricci-Cabello, Ignacio, Stevens, Sarah, Dalton, Andrew R. H., Griffiths, Robert I., Campbell, John L., and Valderas, Jose M.
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Quality control -- Analysis -- Research ,Medical care -- United Kingdom -- Analysis -- Research ,Patient satisfaction -- Analysis -- Research ,Quality control ,Business ,Health care industry - Abstract
Objective. To study the relationships between the different domains of quality of primary health care for the evaluation of health system performance and for informing policy decision making. Data Sources. A total of 137 quality indicators collected from 7,607 English practices between 2011 and 2012. Study Design. Cross-sectional study at the practice level. Indicators were allocated to subdomains of processes of care ('quality assurance,' 'education and training,' 'medicine management,' 'access,' 'clinical management,' and 'patient-centered care'), health outcomes ('intermediate outcomes' and 'patient-reported health status'), and patient satisfaction. The relationships between the subdomains were hypothesized in a conceptual model and subsequently tested using structural equation modeling. Principal Findings. The model supported two independent paths. In the first path, 'access' was associated with 'patient-centered care' ([beta] = 0.63), which in turn was strongly associated with 'patient satisfaction' ([beta] = 0.88). In the second path, 'education and training' was associated with 'clinical management' ([beta] = 0.32), which in turn was associated with 'intermediate outcomes' ([beta] = 0.69). 'Patient-reported health status' was weakly associated with 'patient-centered care' ([beta] = -0.05) and 'patient satisfaction' ([beta] = 0.09), and not associated with 'clinical management' or 'intermediate outcomes.' Conclusions. This is the first empirical model to simultaneously provide evidence on the independence of intermediate health care outcomes, patient satisfaction, and health status. The explanatory paths via technical quality clinical management and patient centeredness offer specific opportunities for the development of quality improvement initiatives. Key Words. Primary health care, clinical quality, health care, patient experience, quality indicators, quality of health care, technical quality of care, Providing high-quality clinical care is a clear priority for most health care systems (Kocher, Emanuel, and DeParle 2010). There is a general agreement that quality of care is a complex [...] more...
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- 2018
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5. Cost-effectiveness of a paclitaxel-eluting stent (Eluvia) compared to Zilver PTX for endovascular femoropopliteal intervention
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Gray, William A., Griffiths, Robert I., Elroy, Peter W. M., Amorosi, Stacey L., McGovern, Alysha M., Jaff, Michael R., Akehurst, Ron, and Müller-Hülsbeck, Stefan
- Abstract
AbstractObjectivesAntiproliferative therapies based on paclitaxel have been developed to extend the durability of endovascular interventions for lower-extremity atherosclerotic peripheral artery disease, resulting in improved primary vessel patency and fewer target lesion revascularizations. This study evaluated the cost-effectiveness of the sustained-release, paclitaxel-eluting Eluvia stent (Boston Scientific, Marlborough, MA) versus the paclitaxel-coated Zilver PTX stent (Cook Medical, Bloomington, IN) for endovascular intervention in the superficial femoral or proximal popliteal artery.DesignA microsimulation model was constructed from a United States Medicare perspective with a 24-month time horizon. Patients entering the model were assigned to initial endovascular intervention with either Eluvia or Zilver PTX. Each month patients were exposed to the risks of primary vessel patency loss, target lesion revascularization, amputation, and death. Clinical input parameters were taken from a randomized trial (IMPERIAL) comparing the two interventions at 24-months follow-up. Cost parameters were obtained from analyses of Medicare administrative and claims data. Cost-effectiveness analysis entailed sampling a complete set of clinical and cost parameters from their respective distributions, and then running cohorts of 10,000 patients through each intervention arm of the model. One-way and probabilistic sensitivity analyses were performed.ResultsIn the base case microsimulation, at 24 months, the modeled target lesion revascularization was 11.6% for Eluvia and 19.0% for Zilver PTX, and the mean total direct costs were $20,010 and $21,356, respectively (Eluvia average savings=$1,346). In probabilistic sensitivity analyses, Eluvia was cost-effective in 87.8% of all simulations at a willingness-to-pay threshold of $10,000 per target lesion revascularization prevented. Eluvia was more effective and less costly (dominant) than Zilver PTX in 73.6% of simulations.ConclusionsIn this comparison of a paclitaxel-eluting to a paclitaxel-coated stent for endovascular femoropopliteal intervention, Eluvia was more effective and less costly (dominant) than Zilver PTX from a US Medicare perspective. These findings should be considered when formulating reimbursement policy and clinical practice guidelines. more...
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- 2022
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6. AI and Poetry.
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GRIFFITHS, ROBERT
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POETRY writing ,HUMAN-machine systems ,GEMINI (Chatbot) - Abstract
The article discusses the emergence of AI technologies like Google's chatbot, Bard, which threatens traditional writing jobs and challenges the role of poets, prompting reflections on the evolving landscape of creativity and human-machine interaction. more...
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- 2024
7. Universals and Particulars.
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GRIFFITHS, ROBERT
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AUTHORSHIP ,POETRY writing - Abstract
The article stresses the importance of particularity in writing especially in poetry writing.
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- 2022
8. Economic impact of immunization against rotavirus gastroenteritis: evidence from a clinical trial
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Griffiths, Robert I., Anderson, Gerard F., Powe, Neil R., Oliveras, Elizabeth, Herbert, Robert J., Grant, Cameron C., and Davidson, Bruce L.
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Rotavirus infections -- Prevention ,Immunization of infants -- Economic aspects ,Medical care, Cost of -- Analysis ,Gastroenteritis in children -- Prevention ,Health - Abstract
Objective: To estimate the economic impact of immunization against rotavirus gastroenteritis in an infant population in the United States. Design: Cost identification and break-even analyses from the perspective of society, nested within a phase 3, randomized, double-blind, placebo-controlled trial. Patients: Infants (N=1278), aged 6 to 22 weeks, enrolled during the summer and fall of 1991 and followed up until July 1, 1992. Intervention: Immunization schedule of three doses of orally administered tetravalent or serotype I rhesus rotavirus vaccine, or placebo. Main Outcome Measures: Incidence of rotavirus gastroenteritis, total direct medical costs, direct nonmedical costs, and indirect costs of rotavirus and nonrotavirus gastroenteritis for the duration of the study and of any illness during 5 days after each dose. The cost of the vaccine was not included. Results: Median total cost per infant among the 1 187 infants who completed the immunization schedule was $9 in the tetravalent vaccine group, $9 in the serotype I vaccine group, and $49 in the placebo group (P=.01). Rotavirus gastroenteritis occurred in 195 infants (16%): 13% (51/398) in the tetravalent group, 12% (47/404) in the serotype 1 group, and 25% (97/385) in the placebo group (P, The cost of immunizing newborns against rotavirus gastroenteritis, a cause of severe infant diarrhea, may be close to $12 per child. Researchers administered three oral doses of two different vaccines or a placebo to 1,187 children between 6 and 22 weeks old. The treatment group received either tetravalent or serotype 1 rhesus rotavirus vaccines. One fourth of the infants in the placebo group had episodes of rotavirus gastroenteritis compared to 12% to 13% in the vaccine groups. Extensive cost analysis determined a break-even point of $11 or $12 per infant. Rotavirus vaccines may be effective in controlling rotavirus gastroenteritis and disease-associated costs. Fewer cases of infant diarrhea would probably lower anxiety among parents and reduce related inconveniences, such as productivity at work. more...
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- 1995
9. The production of dialysis by for-profit versus not-for-profit freestanding renal dialysis facilities
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Griffiths, Robert I., Powe, Neil R., Gaskin, Darrell J., Anderson, Gerard F., de Lissovoy, Gregory V., and Whelton, Paul K.
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Hemodialysis facilities -- Evaluation ,Medical care -- Utilization ,Hemodialysis patients -- Care and treatment - Abstract
Objective. A study was conducted to determine whether for-profit and not-for-profit freestanding renal dialysis facilities differ with respect to efficiency in the production of dialysis treatments. Data Sources/Study Setting. National data on 1,224 Medicare-certified freestanding dialysis facilities were obtained from the Health Care Financing Administration's (HCFA) 1990 Independent Renal Dialysis Facility Cost Report. Data on Medicare patients receiving care at these facilities during 1990 were obtained from HCFA's End Stage Renal Disease (ESRD) Program Management and Medical Information System (PMMIS). Study Design. Ordinary least squares regression (OLS) was used to estimate the association between monthly output of dialysis treatments in 1990 and (a) facility capital and labor inputs, (b) facility ownership characteristics, and (c) case-mix characteristics. Data Collection/Extraction Methods. Facility and patient level data were extracted from the Facility Cost Report and the PMMIS databases, respectively. Patient level data were aggregated by facility and merged with facility level data. Principal Findings. For-profit sole proprietorships, for-profit partnerships and for-profit corporations each produced significantly more dialysis treatments per month than not-for-profits, adjusting for quantities of resource inputs and case-mix characteristics. Conclusion. For-profit facilities appear to be more efficient producers of dialysis treatments than not-for-profits. Further study should address whether other factors such as differences in severity of disease or in quality of care are responsible for these observations. Keywords. For-profit medical care, renal dialysis, health economics, Medicare, end stage renal disease, The rise of the for-profit enterprise in health care has prompted debate over whether for-profit health care providers are more efficient than not-for-profits (Siafacu 1981; Held and Pauly 1983; Relman [...] more...
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- 1994
10. A review of the first year of Medicare coverage of erythropoietin
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Griffiths, Robert I., Powe, Neil R., Greer, Joel, De Lissovoy, Gregory, Anderson, Gerard F., Whelton, Paul K., Watson, Alan J., and Eggers, Paul W.
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Medicare -- Economic aspects -- Evaluation -- Usage ,Erythropoietin, Recombinant -- Usage -- Economic aspects ,Prescription drug plans -- Evaluation -- Usage ,Drug utilization -- Evaluation -- Economic aspects -- Usage ,Business ,Health care industry ,Evaluation ,Economic aspects ,Usage - Abstract
Recombinant human erythropoietin (rHuEPO) is a new drug for treating anemia associated with end stage renal disease (ESRD). In a study of rHuEPO diffusion, costs, and effectiveness, we analyze ESRD program data and all claims submitted to Medicare for reimbursement of rHuEPO administered to ESRD dialysis patients. Access to rHuEPO was rapid and extensive during the first year of Medicare coverage. Dosing of rHuEPO and achieved hematocrit were lower than expected based on the results of clinical trials. rHuEPO cost Medicare $144 million in its first year. The analysis of insurance claims data allowed effective monitoring of access, costs, and effectiveness of this new biotechnology., BACKGROUND Pharmaceutical products developed through advances in recombinant biotechnology have been reviewed by the Food and Drug Administration (FDA) and are now in use in routine clinical practice. Some of [...] more...
- Published
- 1994
11. All in the analysis: incorporating functional ingredients into dairy products involves thorough analysis, according to Dr Robert Griffiths of Reading Scientific Services (RSSL)
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Griffiths, Robert
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Dairy products ,Phytosterols ,Omega-3 fatty acids ,Agricultural industry ,Business ,Business, international ,Food and beverage industries - Abstract
Dairy products have been the focus of much innovation in recent years, with an increasing number incorporating functional ingredients. It is now common to see different dairy products that contain [...] more...
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- 2009
12. Climate change alters temporal dynamics of alpine soil microbial functioning and biogeochemical cycling via earlier snowmelt
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Broadbent, Arthur A D, Snell, Helen S K, Michas, Antonios, Pritchard, William J, Newbold, Lindsay, Cordero, Irene, Goodall, Tim, Schallhart, Nikolaus, Kaufmann, Ruediger, Griffiths, Robert I, Schloter, Michael, Bahn, Michael, and Bardgett, Richard D more...
- Abstract
Soil microbial communities regulate global biogeochemical cycles and respond rapidly to changing environmental conditions. However, understanding how soil microbial communities respond to climate change, and how this influences biogeochemical cycles, remains a major challenge. This is especially pertinent in alpine regions where climate change is taking place at double the rate of the global average, with large reductions in snow cover and earlier spring snowmelt expected as a consequence. Here, we show that spring snowmelt triggers an abrupt transition in the composition of soil microbial communities of alpine grassland that is closely linked to shifts in soil microbial functioning and biogeochemical pools and fluxes. Further, by experimentally manipulating snow cover we show that this abrupt seasonal transition in wide-ranging microbial and biogeochemical soil properties is advanced by earlier snowmelt. Preceding winter conditions did not change the processes that take place during snowmelt. Our findings emphasise the importance of seasonal dynamics for soil microbial communities and the biogeochemical cycles that they regulate. Moreover, our findings suggest that earlier spring snowmelt due to climate change will have far reaching consequences for microbial communities and nutrient cycling in these globally widespread alpine ecosystems. more...
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- 2021
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13. Not cricket.
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Griffiths, Robert and Whale, Stephen
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Cricket -- Laws, regulations and rules ,Sports officiating -- Laws, regulations and rules ,Government regulation - Published
- 2006
14. Karl Marx oration 2020
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Bains, Joginder and Griffiths, Robert
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- 2020
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15. A Reconsideration of Walter de la Mare.
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Griffiths, Robert
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- RECONSIDERATION of Walter de la Mare, A (Poem), GRIFFITHS, Robert
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- 2020
16. Opposing actions of renal tubular- and myeloid-derived porcupine in obstruction-induced kidney fibrosis
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Lu, Xiaohan, Rudemiller, Nathan P., Ren, Jiafa, Wen, Yi, Yang, Bo, Griffiths, Robert, Privratsky, Jamie R., Madan, Babita, Virshup, David M., and Crowley, Steven D.
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Wnt/β-catenin signaling is essential in the pathogenesis of renal fibrosis. We previously reported inhibition of the Wnt O-acyl transferase porcupine, required for Wnt secretion, dramatically attenuates kidney fibrosis in the murine unilateral ureteral obstruction model. Here, we investigated the tissue-specific contributions of porcupine to renal fibrosis and inflammation in ureteral obstruction using mice with porcupine deletion restricted to the kidney tubular epithelium or infiltrating myeloid cells. Obstruction of the ureter induced the renal mRNA expression of porcupine and downstream targets, β-catenin, T-cell factor, and lymphoid enhancer factor in wild type mice. Renal tubular specific deficiency of porcupine reduced the expression of collagen I and other fibrosis markers in the obstructed kidney. Moreover, kidneys from obstructed mice with tubule-specific porcupine deficiency had reduced macrophage accumulation with attenuated expression of myeloid cytokine and chemokine mRNA. In co-culture with activated macrophages, renal tubular cells from tubular-specific porcupine knockout mice had blunted induction of fibrosis mediators compared with wild type renal tubular cells. In contrast, macrophages from macrophage-specific porcupine deficient mice in co-culture with wild type renal tubular cells had markedly enhanced expression of pro-fibrotic cytokines compared to wild type macrophages. Consequently, porcupine deletion specifically within macrophages augmented renal scar formation following ureteral obstruction. Thus, our experiments suggest a benefit of interrupting Wnt secretion specifically within the kidney epithelium while preserving Wnt O-acylation in infiltrating myeloid cells during renal fibrogenesis. more...
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- 2019
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17. Persistence of dissolved organic matter explained by molecular changes during its passage through soil
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Roth, Vanessa-Nina, Lange, Markus, Simon, Carsten, Hertkorn, Norbert, Bucher, Sebastian, Goodall, Timothy, Griffiths, Robert, Mellado-Vázquez, Perla, Mommer, Liesje, Oram, Natalie, Weigelt, Alexandra, Dittmar, Thorsten, and Gleixner, Gerd more...
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Dissolved organic matter affects fundamental biogeochemical processes in the soil such as nutrient cycling and organic matter storage. The current paradigm is that processing of dissolved organic matter converges to recalcitrant molecules (those that resist degradation) of low molecular mass and high molecular diversity through biotic and abiotic processes. Here we demonstrate that the molecular composition and properties of dissolved organic matter continuously change during soil passage and propose that this reflects a continual shifting of its sources. Using ultrahigh-resolution mass spectrometry and nuclear magnetic resonance spectroscopy, we studied the molecular changes of dissolved organic matter from the soil surface to 60 cm depth in 20 temperate grassland communities in soil type Eutric Fluvisol. Applying a semi-quantitative approach, we observed that plant-derived molecules were first broken down into molecules containing a large proportion of low-molecular-mass compounds. These low-molecular-mass compounds became less abundant during soil passage, whereas larger molecules, depleted in plant-related ligno-cellulosic structures, became more abundant. These findings indicate that the small plant-derived molecules were preferentially consumed by microorganisms and transformed into larger microbial-derived molecules. This suggests that dissolved organic matter is not intrinsically recalcitrant but instead persists in soil as a result of simultaneous consumption, transformation and formation. Dissolved organic matter is persistent in soil owing to continuous consumption and transformation rather than owing to its recalcitrant molecular properties, according to analyses of molecular changes of dissolved organic matter as it passes through soil. more...
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- 2019
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18. Stimulating Type 1 Angiotensin Receptors on T Lymphocytes Attenuates Renal Fibrosis
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Wen, Yi, Rudemiller, Nathan P., Zhang, Jiandong, Jeffs, Alexander D., Griffiths, Robert, Lu, Xiaohan, Ren, Jiafa, Privratsky, Jamie, and Crowley, Steven D.
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Most forms of chronic kidney disease culminate in renal fibrosis that heralds organ failure. In contrast to the protective effects of globally blocking type 1 angiotensin (AT1) receptors throughout the body, activating AT1receptors directly on immune cells may serve protective functions. However, the effects of stimulating the T-cell AT1receptor on the progression of renal fibrosis remain unknown. In this study, mice with T-cell–specific deletion of the dominant murine AT1receptor isoform Lck-Cre Agtraflox/flox[total knockout (TKO)] and wild-type (WT) controls were subjected to the unilateral ureteral obstruction model of kidney fibrosis. Compared with WT controls, obstructed kidneys from TKO mice at day 14 had increased collagen 1 deposition. CD4+T cells, CD11b+Ly6Chimyeloid cells, and mRNA levels of Th1 inflammatory cytokines are elevated in obstructed TKO kidneys, suggesting that augmented Th1 responses in the TKO mice may exaggerate renal fibrosis by driving proinflammatory macrophage differentiation. In turn, T-bet deficient (T-bet knockout) mice lacking Th1 responses have attenuated collagen deposition after unilateral ureteral obstruction. We conclude that activating the AT1receptor on T cells mitigates renal fibrogenesis by inhibiting Th1 differentiation and renal accumulation of profibrotic macrophages. more...
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- 2019
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19. Engagement with China Was It a Mistake? U.S. expectations may have been unrealistic, but there is much to remember and learn from our previous dealings with Beijing.
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GRIFFITHS, ROBERT
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HUMAN rights , *ECONOMIC development , *FOREIGN investments ,CHINA-United States relations ,TIANANMEN Square Massacre, China, 1989 - Abstract
The article discusses history of the U.S. foreign policy toward China. Topics discussed include need for new and less-engaging approach for China's unbalanced trade, suppression of political freedoms and human rights; information on Tiananmen Square massacre in 1989; and economic growth in China by foreign investment. more...
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- 2021
20. Vascular type 1 angiotensin receptors control blood pressure by augmenting peripheral vascular resistance in female mice
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Wolf, Erin, Diaz, Edward J., Hollis, Alison N., Hoang, Thien A., Azad, Hooman A., Bendt, Katharine M., Griffiths, Robert C., and Sparks, Matthew A.
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Angiotensin II (ANG II) is a major mediator of hypertension pathogenesis. In addition, there are well-documented differences in expression of the renin-angiotensin system (RAS) components and ANG II responses between males and females, which may explain sex differences in blood pressure (BP) and hypertension epidemiology. We previously showed that type 1A angiotensin (AT1A) receptors in vascular smooth muscle cells (VSMCs) play a critical role in BP regulation and hypertension pathogenesis, but these studies were carried out in male mice. Therefore, the major goal of the current studies was to examine the impact of VSMC AT1Areceptors on BP and hypertension pathogenesis in female mice. We found that elimination of VSMC AT1Areceptors in female mice reduced (≈8 mmHg) baseline BP without altering sodium sensitivity. The severity of ANG II-induced hypertension was diminished (≈33% reduction in BP), particularly during the last 2 wk of chronic ANG II infusion, compared with controls, but natriuresis was not altered during the first 5 days of ANG II infusion. Urinary norepinephrine levels were enhanced in female SMKO compared with control mice. There was a virtually complete elimination of ANG II-induced kidney hemodynamic responses with attenuation of acute vasoconstrictor responses in the systemic vasculature. These findings demonstrate that direct vascular actions of AT1Areceptors play a prominent role in BP control and hypertension pathogenesis in female mice. more...
- Published
- 2018
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21. Star of Europe
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Griffiths, Robert
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Literature/writing ,Political science - Abstract
It is one thing to disagree with the editorial policy of the Morning Star, but quite another to misrepresent it as grotesquely as Jim Denham does ('Red all over', 31 [...]
- Published
- 2015
22. The ball-tampering affair.
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Griffiths, Robert and Whale, Stephen
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Sports officiating -- Laws, regulations and rules ,Sportsmanship -- Laws, regulations and rules ,Government regulation - Published
- 2007
23. Methods for estimating costs in patients with hyperlipidemia experiencing their first cardiovascular event in the United Kingdom
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Danese, Mark D., Gleeson, Michelle, Griffiths, Robert I., Catterick, David, and Kutikova, Lucie
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AbstractAims:Methods for integrating external costs into clinical databases are not well-characterized. The purpose of this research was to describe and implement methods for estimating the cost of hospitalizations, prescriptions, and general practitioner and specialist visits used to manage hyperlipidemia patients experiencing cardiovascular (CV) events in the United Kingdom (UK).Methods:This study was a retrospective cohort study using the Clinical Practice Research Datalink and Hospital Episode Statistics data. Costs were incorporated based on reference costs from the National Health Service,and labor costs from the Personal Social Services Research Unit. The study population included patients seen by general practitioners in the UK from 2006–2012. Patients ≥18 years were selected at the time of their first CV-related hospitalization defined as myocardial infarction, ischemic stroke, heart failure, transient ischemic attack, unstable angina, or revascularization. To be included, patients must have received ≥2 lipid-lowering therapies. Outcome measures included healthcare utilization and direct medical costs for hospitalizations, medications, general practitioner visits, and specialist visits during the 6-month acute period, starting with the CV hospitalization, and during the subsequent 30-month long-term period.Results:There were 24,093 patients with a CV hospitalization included in the cohort. This study identified and costed 69,240 hospitalizations, 673,069 GP visits, 32,942 specialist visits, and 2,572,792 prescriptions,representing 855 unique drug and dose combinations. The mean acute period and mean annualized long-term period costs (2014£) were £4,060 and £1,433 for hospitalizations, £377 and £518 for GP visits, £59 and £103 for specialist visits, and £98 and £209 for medications.Conclusions:Hospital costs represent the largest portion of acute and long-term costs in this population. Detailed costing using utilization data is feasible and representative of UK clinical practice, but is labor intensive. The availability of a standardized coding system in the UK drug costing data would greatly facilitate drug costing. more...
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- 2017
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24. C-C Motif Chemokine 5 Attenuates Angiotensin II–Dependent Kidney Injury by Limiting Renal Macrophage Infiltration
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Rudemiller, Nathan P., Patel, Mehul B., Zhang, Jian-dong, Jeffs, Alexander D., Karlovich, Norah S., Griffiths, Robert, Kan, Matthew J., Buckley, Anne F., Gunn, Michael D., and Crowley, Steven D.
- Abstract
Inappropriate activation of the renin angiotensin system (RAS) is a key contributor to the pathogenesis of essential hypertension. During RAS activation, infiltration of immune cells into the kidney exacerbates hypertension and renal injury. However, the mechanisms underpinning the accumulation of mononuclear cells in the kidney after RAS stimulation remain unclear. C-C motif chemokine 5 (CCL5) drives recruitment of macrophages and T lymphocytes into injured tissues, and we have found that RAS activation induces CCL5 expression in the kidney during the pathogenesis of hypertension and renal fibrosis. We therefore evaluated the contribution of CCL5 to renal damage and fibrosis in hypertensive and normotensive models of RAS stimulation. Surprisingly, during angiotensin II-induced hypertension, CCL5-deficient (knockout, KO) mice exhibited markedly augmented kidney damage, macrophage infiltration, and expression of proinflammatory macrophage cytokines compared with wild-type controls. When subjected to the normotensive unilateral ureteral obstruction model of endogenous RAS activation, CCL5 KO mice similarly developed more severe renal fibrosis and greater accumulation of macrophages in the kidney, congruent with enhanced renal expression of the macrophage chemokine CCL2. In turn, pharmacologic inhibition of CCL2 abrogated the differences between CCL5 KO and wild-type mice in kidney fibrosis and macrophage infiltration after unilateral ureteral obstruction. These data indicate that CCL5 paradoxically limits macrophage accumulation in the injured kidney during RAS activation by constraining the proinflammatory actions of CCL2. more...
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- 2016
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25. Experimental inhibition of porcupine-mediated Wnt O-acylation attenuates kidney fibrosis
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Madan, Babita, Patel, Mehul B., Zhang, Jiandong, Bunte, Ralph M., Rudemiller, Nathan P., Griffiths, Robert, Virshup, David M., and Crowley, Steven D.
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Activated Wnt signaling is critical in the pathogenesis of renal fibrosis, a final common pathway for most forms of chronic kidney disease. Therapeutic intervention by inhibition of individual Wnts or downstream Wnt/β-catenin signaling has been proposed, but these approaches do not interrupt the functions of all Wnts nor block non-canonical Wnt signaling pathways. Alternatively, an orally bioavailable small molecule, Wnt-C59, blocks the catalytic activity of the Wnt-acyl transferase porcupine, and thereby prevents secretion of all Wnt isoforms. We found that inhibiting porcupine dramatically attenuates kidney fibrosis in the murine unilateral ureteral obstruction model. Wnt-C59 treatment similarly blunts collagen mRNA expression in the obstructed kidney. Consistent with its actions to broadly arrest Wnt signaling, porcupine inhibition reduces expression of Wnt target genes and bolsters nuclear exclusion of β-catenin in the kidney following ureteral obstruction. Importantly, prevention of Wnt secretion by Wnt-C59 blunts expression of inflammatory cytokines in the obstructed kidney that otherwise provoke a positive feedback loop of Wnt expression in collagen-producing fibroblasts and epithelial cells. Thus, therapeutic targeting of porcupine abrogates kidney fibrosis not only by overcoming the redundancy of individual Wnt isoforms but also by preventing upstream cytokine-induced Wnt generation. These findings reveal a novel therapeutic maneuver to protect the kidney from fibrosis by interrupting a pathogenic crosstalk loop between locally generated inflammatory cytokines and the Wnt/β-catenin signaling pathway. more...
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- 2016
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26. Einstein and (Coincidentally) the Modern Poets.
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Griffiths, Robert
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POETS ,PHYSICS in literature - Abstract
The article explores the coincidental contributions of physicist Albert Einstein on the modern poets.
- Published
- 2016
27. HOSPITAL DOWNSTREAM REVENUE FROM MEDICARE PATIENTS MAY SUPPORT SCREENING AND DIAGNOSIS FOR LUNG CANCER
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CRAMER, GERI, I GRIFFITHS, ROBERT, M HARGENS, LIESL, and BHORA, FAIZ
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- 2022
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28. Fat chance: the Hilditch symposium: compositional analysis, organised by the SCI Oils & Fats Group, will look in detail at the most recent procedures available to those working in this fascinating field
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Griffiths, Robert
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Oils and fats -- Analysis ,Oils and fats industry -- Conferences, meetings and seminars ,Oils and fats industry -- Analysis ,Waxes industry -- Conferences, meetings and seminars ,Waxes industry -- Analysis ,Business ,Chemicals, plastics and rubber industries - Published
- 2007
29. Uneasy bedfellows?
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Griffiths, Robert and Whale, Stephen
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Sports associations -- Contracts ,Contracts -- Laws, regulations and rules ,Duty of care (Law) -- Laws, regulations and rules ,West Bromwich Albion Football Club v. El-Safty (2006 E.W.C.A. Civ. 1299) ,Government regulation ,Contract agreement - Published
- 2006
30. 'Best ever' Linux distribution
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Griffiths, Robert
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I never fail to find at least one useful program on your enclosed CDs, but the Knoppix Linux CD is the best ever (October issue). It loaded and ran beautifully […]
- Published
- 2003
31. The ?-Fleming-Viot Process and a Connection with Wright-Fisher Diffusion
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Griffiths, Robert C.
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The d-dimensional ?-Fleming-Viot generator acting on functions g(x), with xbeing a vector of dallele frequencies, can be written as a Wright-Fisher generator acting on functions gwith a modified random linear argument of xinduced by partitioning occurring in the ?-Fleming-Viot process. The eigenvalues and right polynomial eigenvectors are easy to see from this representation. The two-dimensional process, which has a one-dimensional generator, is considered in detail. A nonlinear equation is found for the Green's function. In a model with genic selection a proof is given that there is a critical selection value such that if the selection coefficient is greater than or equal to the critical value then fixation, when the boundary 1 is hit, has probability 1 beginning from any nonzero frequency. This is an analytic proof different from the proofs of Der, Epstein and Plotkin (2011) and Foucart (2013). An application in the infinitely-many-alleles ?-Fleming-Viot process is finding an interesting identity for the frequency spectrum of alleles that is based on size biasing. The moment dual process in the Fleming-Viot process is the usual ?-coalescent tree back in time. The Wright-Fisher representation using a different set of polynomials gn(x) as test functions produces a dual death process which has a similarity to the Kingman coalescent and decreases by units of one. The eigenvalues of the process are analogous to the Jacobi polynomials when expressed in terms of gn(x), playing the role of xn. Under the stationary distribution when there is mutation, is analogous to the nth moment in a beta distribution. There is a d-dimensional version gn(X), and even an intriguing Ewens' sampling formula analogy when d? 8. more...
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- 2014
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32. Development and Pilot of Case Manager: A Virtual-Patient Experience for Veterinary Students
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Byron, Julie K., Johnson, Susan E., Allen, L. Clare V., Brilmyer, Cheryl, and Griffiths, Robert P.
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There is an increasing demand in veterinary education to engage students, teach and reinforce clinical reasoning, and provide access anytime/anywhere to quality learning opportunities. In addition, accrediting bodies are asking for more concrete documentation of essential clinical-skills outcomes. Unfortunately, during the clinical year in a referral hospital setting, students are at the mercy of chance regarding the types of cases they will encounter and the opportunities they will have to participate. Patient- and case-simulation technology is becoming more popular as a way to achieve these objectives in human and veterinary medical education. Many of the current options available to the veterinary medical education community to develop virtual-patient cases are too time-consuming, cost prohibitive, or difficult for the instructor or learner to use. In response, we developed a learning tool, Case Manager, which is low-cost and user-friendly. Case Manager was designed to meet the demands of veterinary education by providing students with an opportunity to cultivate clinical reasoning skills and allowing for real-time student feedback. We launched a pilot test with 37 senior veterinary medical students as part of their Small Animal Internal Medicine clinical rotation. Students reported that Case Manager increased their engagement with the material, improved diagnostic and problem-solving skills, and broadened their exposure to a variety of cases. In addition, students felt that Case Manager was superior to a more traditional, less interactive case presentation format. more...
- Published
- 2014
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33. Epistemic restrictions in Hilbert space quantum mechanics.
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Griffiths, Robert B.
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QUANTUM measurement , *HILBERT space , *PROBLEM solving , *EPISTEMICS , *QUANTUM mechanics , *QUANTUM information theory , *MATHEMATICAL models - Abstract
A resolution of the quantum measurement problem(s) using the consistent histories interpretation yields in a rather natural way a restriction on what an observer can know about a quantum system, one that is also consistent with some results in quantum information theory. This analysis provides a quantum mechanical understanding of some recent work that shows that certain kinds of quantum behavior are exhibited by a fully classical model if by hypothesis an observer's knowledge of its state is appropriately limited. [ABSTRACT FROM AUTHOR] more...
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- 2013
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34. Fast protocols for local implementation of bipartite nonlocal unitaries.
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Yu, Li, Griffiths, Robert B., and Cohen, Scott M.
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QUANTUM entanglement , *BIPARTITE graphs , *EIGHTFOLD way (Nuclear physics) , *QUANTUM theory , *QUANTUM information science - Abstract
In certain cases the communication time required to deterministically implement a nonlocal bipartite unitary using prior entanglement and local operations and classical communication can be reduced by a factor of two. We introduce two such "fast" protocols and illustrate them with various examples. For some simple unitaries, the entanglement resource is used quite efficiently. The problem of exactly which unitaries can be implemented by these two protocols remains unsolved, though there is some evidence that the set of implementable unitaries may expand at the cost of using more entanglement. [ABSTRACT FROM AUTHOR] more...
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- 2012
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35. Automated Assessment of Bradykinesia and Dyskinesia in Parkinson's Disease
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Griffiths, Robert I., Arfon, Sian, Xu, Zheng Ming, Johnson, William, Evans, Andrew, and Kempster, Peter
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There is a need for objective measures of dyskinesia and bradykinesia of Parkinson's disease (PD) that are continuous throughout the day and related to levodopa dosing. The output of an algorithm that calculates dyskinesia and bradykinesia scores every two minutes over 10 days (PKG: Global Kinetics Corporation) was compared with conventional rating scales for PD in PD subjects. The algorithm recognises bradykinesia as movements made with lower acceleration and amplitude and with longer intervals between movement. Similarly the algorithm recognises dyskinesia as having movements of normal amplitude and acceleration but with shorter periods without movement. The distribution of the bradykinesia and dyskinesia scores from PD subjects differed from that of normal subjects. The algorithm predicted the clinical dyskinesia rating scale AIMS with a 95% margin of error of 3.2 units compared with the inter-rater 95% limits of agreement from 3 neurologists of −3.4 to +4.3 units. Similarly the algorithm predicted the UPDRS III score with a margin of error similar to the inter-rater limits of agreement. Improvement in scores in response to changes in medication could be assessed statistically in individual patients. This algorithm provides objective, continuous and automated assessment of the clinical features of bradykinesia and dyskinesia in PD. more...
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- 2012
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36. LETTERS.
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Lightfoot, Albert, Blyth, Steve, Gray, Randall, Fahy, Frank, Lucas, Richard, Beck, David, Emes, Derek, Griffiths, Robert, Bainbridge, Henry, Young, Paul, Goss, John, Aston, Max, Collins, Stan, Stanley, Geoff, D'Oliveiro, Lawrence, Green, Malcolm, Welch, Stephen, and Evans, Brian more...
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GOBEKLI Tepe (Turkey) ,ASTRONOMICAL observatories ,MIND & body ,COGNITION ,THOUGHT & thinking - Abstract
Several letters to the editor are presented in response to articles in previous issues, including one about the Göbekli Tepe archaeological site in the August 17, 2013 issue, an editorial in the September 21, 2013 issue, and "Mind Into Matter" by Lambros Malafouris in the September 7, 2013 issue. more...
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- 2013
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37. Addition of rituximab to chemotherapy alone as first-line therapy improves overall survival in elderly patients with mantle cell lymphoma
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Griffiths, Robert, Mikhael, Joseph, Gleeson, Michelle, Danese, Mark, and Dreyling, Martin
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Clinical trials have demonstrated that rituximab improves overall survival in non-Hodgkin lymphoma (NHL), except in mantle cell lymphoma (MCL). We used Surveillance Epidemiology and End Results (SEER)–Medicare data to compare survival in older MCL patients who began chemotherapy with or without rituximab within 180 days of diagnosis. Patients were followed from diagnosis (January 1999 to December 2005) until death or the end of observation (December 2007). Medicare administrative and claims data were used to identify the date and cause of death and the immunochemotherapy regimen. Of 638 patients, the mean age at diagnosis was 75 years, 75% had stage III/IV disease, 67% had extranodal involvement, and 64% received rituximab. The average length of first-line treatment was 21 weeks, with no difference between the 2 groups (P= .76). Median survival was 27 months for chemotherapy alone, compared with 37 months for chemotherapy plus rituximab (P< .001). In multivariate analysis of 2-year survival, rituximab plus chemotherapy was associated with lower all-cause (hazard ratio [HR] 0.58; 95% confidence interval [CI] 0.41-0.82; P< .01), and cancer-specific (HR 0.56; 95% CI 0.37-0.84; P< .01) mortality. Results were similar when using the entire observation period, propensity score analysis, and limiting chemotherapy to CHOP/CHOP-like. We conclude that first-line chemotherapy including rituximab is associated with significantly improved survival in older patients diagnosed with MCL. more...
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- 2011
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38. Role of AT1receptor-mediated salt retention in angiotensin II-dependent hypertension
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Crowley, Steven D., Zhang, Jiandong, Herrera, Maria, Griffiths, Robert, Ruiz, Phillip, and Coffman, Thomas M.
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Activation of type 1 angiotensin II (AT1) receptors in the kidney promotes blood pressure elevation and target organ damage, but whether renal AT1receptors influence the level of hypertension by stimulating sodium retention or by raising systemic vascular resistance has not been established. In the current studies, we used a kidney cross-transplantation strategy to determine whether increased sodium reabsorption by AT1receptors in the kidney mediates the chronic hypertensive response to angiotensin II. We found this to be true. In addition, we also identified a second, nontrivial component of blood pressure elevation induced by activation of renal AT1receptors that is sodium-independent. As the kidney has the capacity to limit the transmission of elevated systemic blood pressure into the renal microcirculation, prior studies struggled to clearly discriminate the relative contributions of blood pressure elevation vs. activation of AT1receptors to hypertensive kidney injury. In our model, we found that rapid surges in blood pressure, which may overcome the kidney's capacity to prevent perturbations in renal hemodynamics, correlate closely with kidney damage in hypertension. Moreover, maximal kidney injury in hypertension may require activation of a pool of nonrenal, systemic AT1receptors. These studies provide insight into precise mechanisms through which AT1receptor blockade influences the progression of hypertensive kidney disease. more...
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- 2011
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39. Entanglement requirements for implementing bipartite unitary operations.
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Stahlke, Dan and Griffiths, Robert B.
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QUANTUM entanglement , *DUALITY theory (Mathematics) , *WAVE-particle duality , *MATHEMATICAL analysis , *QUANTUM theory - Abstract
We prove, using a method based on map-state duality, lower bounds on entanglement resources needed to deterministically implement a bipartite unitary using separable (SEP) operations, which include LOCC (local operations and classical communication) as a particular case. It is known that the Schmidt rank of an entangled pure state resource cannot be less than the Schmidt rank of the unitary. We prove that if these ranks are equal the resource must be uniformly (maximally) entangled: equal nonzero Schmidt coefficients. Higher rank resources can have less entanglement: we have found numerical examples of Schmidt rank 2 unitaries, which can be deterministically implemented, by either SEP or LOCC, using an entangled resource of two qutrits with less than one ebit of entanglement. [ABSTRACT FROM AUTHOR] more...
- Published
- 2011
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40. An observational study of outcomes after initial infused therapy in Medicare patients diagnosed with chronic lymphocytic leukemia
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Danese, Mark D., Griffiths, Robert I., Gleeson, Michelle, Satram-Hoang, Sacha, Knopf, Kevin, Mikhael, Joseph, and Reyes, Carolina
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The study goal was to characterize older chronic lymphocytic leukemia (CLL) patients and to evaluate outcomes in those patients who initiated infused therapy. Patients 66 years of age and older in the Surveillance, Epidemiology, and End Results (SEER) program with a CLL diagnosis were matched to their Medicare Part A and Part B claims for long-term follow-up. Treatment patterns, survival after initiation of infused therapy, and both hematologic and hospitalization outcomes were assessed. There were 6433 CLL patients identified, and 2040 received infused therapy. Treated patients were categorized as receiving rituximab monotherapy (16%), rituximab plus chemotherapy (14%), and chemotherapy alone (70%) based on the initial 60 days after infusion. Rituximab plus chemotherapy compared with chemotherapy alone was associated with a 25% lower risk of overall mortality (95% confidence interval, 9%-38%). Restricting to patients age 70 years and older did not change the risk reduction for rituximab plus chemotherapy. Hematologic interventions were more common with rituximab plus chemotherapy compared with chemotherapy alone, but there was no difference in all-cause hospitalizations. These analyses, based on observational data, suggest that the benefits of initial therapy with rituximab in a heterogeneous group of older CLL patients are comparable with those demonstrated in younger patients. more...
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- 2011
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41. Sympathetic withdrawal augments cerebral blood flow during acute hypercapnia in sleeping lambs.
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Cassaglia, Priscila A, Griffiths, Robert I, and Walker, Adrian M
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Cerebral sympathetic activity constricts cerebral vessels and limits increases in cerebral blood flow (CBF), particularly in conditions such as hypercapnia which powerfully dilate cerebral vessels. As hypercapnia is common in sleep, especially in sleep disordered breathing, we tested the hypothesis that sympathetic innervation to the cerebral circulation attenuates the CBF increase that accompanies increases in PaCO2 in sleep, particularly in REM sleep when CBF is high. more...
- Published
- 2008
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42. Stimulation of lymphocyte responses by angiotensin II promotes kidney injury in hypertension
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Crowley, Steven D., Frey, Campbell W., Gould, Samantha K., Griffiths, Robert, Ruiz, Phillip, Burchette, James L., Howell, David N., Makhanova, Natalia, Yan, Ming, Kim, Hyung-Suk, Tharaux, Pierre-Louis, and Coffman, Thomas M. more...
- Abstract
Activation of the renin-angiotensin system contributes to the progression of chronic kidney disease. Based on the known cellular effects of ANG II to promote inflammation, we posited that stimulation of lymphocyte responses by ANG II might contribute to the pathogenesis of hypertensive kidney injury. We therefore examined the effects of the immunosuppressive agent mycophenolate mofetil (MMF) on the course of hypertension and kidney disease induced by chronic infusion of ANG II in 129/SvEv mice. Although it had no effect on the severity of hypertension or cardiac hypertrophy, treatment with MMF significantly reduced albuminuria and ameliorated kidney injury, decreasing glomerulosclerosis and reducing lymphocyte infiltration into the renal interstitium. Attenuation of renal pathology with MMF was associated with reduced expression of mRNAs for the proinflammatory cytokines interferon-γ and tumor necrosis factor-α and the profibrotic cytokine transforming growth factor-β. As infiltration of the kidney by T lymphocytes was a prominent feature of ANG II-dependent renal injury, we carried out experiments examining the effects of ANG II on lymphocytes in vitro. We find that exposure of splenic lymphocytes to ANG II causes prominent rearrangements of the actin cytoskeleton. These actions require the activity of Rho kinase. Thus, ANG II exaggerates hypertensive kidney injury by stimulating lymphocyte responses. These proinflammatory actions of ANG II seem to have a proclivity for inducing kidney injury while having negligible actions in the pathogenesis of cardiac hypertrophy. more...
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- 2008
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43. Importance sampling and the two-locus model with subdivided population structure
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Griffiths, Robert C., Jenkins, Paul A., and Song, Yun S.
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The diffusion-generator approximation technique developed by De Iorio and Griffiths (2004a) is a very useful method of constructing importance-sampling proposal distributions. Being based on general mathematical principles, the method can be applied to various models in population genetics. In this paper we extend the technique to the neutral coalescent model with recombination, thus obtaining novel sampling distributions for the two-locus model. We consider the case with subdivided population structure, as well as the classic case with only a single population. In the latter case we also consider the importance-sampling proposal distributions suggested by Fearnhead and Donnelly (2001), and show that their two-locus distributions generally differ from ours. In the case of the infinitely-many-alleles model, our approximate sampling distributions are shown to be generally closer to the true distributions than are Fearnhead and Donnelly's. more...
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- 2008
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44. Coalescent lineage distributions
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Griffiths, Robert C.
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We study identities for the distribution of the number of edges at time tback (i.e. measured backwards) in a coalescent tree whose subtrees have no mutations. This distribution is important in the infinitely-many-alleles model of mutation, where every mutation is unique. The model includes, as a special case, the number of edges in a coalescent tree at time tback when mutation is ignored. The identities take the form of expected values of functions of Zt=eiXt, where Xtis distributed as standard Brownian motion. Associated identities are also found for the distributions of the time to the most recent common ancestor, the time until loss of ancestral lines by coalescence or mutation, and the age of a mutation. Hypergeometric functions play an important role in the identities. The identities are of mathematical interest, as well as potentially being formulae to use for numerical integration or simulation to compute distributions that are usually expressed as alternating-sign series expansions, which are difficult to compute. more...
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- 2006
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45. PTH and the Risks for Hip, Vertebral, and Pelvic Fractures Among Patients on Dialysis
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Danese, Mark D., Kim, John, Doan, Quan V., Dylan, Michelle, Griffiths, Robert, and Chertow, Glenn M.
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Background:Few investigations have described fracture risk and its relation to disorders in calcium (Ca), phosphorus (P), and parathyroid hormone (PTH) metabolism in the end-stage renal disease population. Methods:Laboratory values for Ca, P, and PTH were obtained from Dialysis Morbidity and Mortality Study (DMMS) Waves 1 to 4. Additional data available from the US Renal Data System were used to determine the incidence and associated costs of hip, vertebral, and pelvic fractures in 9,007 patients with nonmissing laboratory values and Medicare as primary payor. Cox proportional hazards and Poisson models were used to analyze time to first fracture and numbers of fractures, respectively. Results:There was no association between Ca or P values and risk for fracture; risks for vertebral and hip fractures and PTH concentrations were U shaped and weakly significant using Poisson regression (P= 0.03). The age- and sex-adjusted mortality rate after fracture was 2.7 times greater (580/1,000 person-years) than for general dialysis patients from the DMMS (217/1,000 person-years). Mean total episodic costs of hip, vertebral, and pelvic fractures were $20,810 ± $16,743 (SD), $17,063 ± $26,201, and $14,475 ± $19,209, respectively. Conclusion:Using data from the DMMS, there were no associations between Ca and P concentrations and risk for fracture. Risks for hip and vertebral fracture were associated weakly with PTH concentration, with the lowest risk observed around a PTH concentration of 300 pg/mL (ng/L). Fractures were associated with high subsequent mortality and costs. Prospective studies are needed to determine whether therapies that maintain PTH concentrations within or near the National Kidney Foundation–Kidney Disease Outcomes Quality Initiative range will result in fewer complications of disordered mineral metabolism. more...
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- 2006
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46. Clinical and Economic Outcomes of Staphylococcus aureusSepticemia in ESRD Patients Receiving Hemodialysis
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Nissenson, Allen R., Dylan, Michelle L., Griffiths, Robert I., Yu, Hsing-Ting, Dean, Bonnie B., Danese, Mark D., and Dubois, Robert W.
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Background:Serious infections are a common problem in patients with end-stage renal disease (ESRD). The purpose of this study is to identify clinical and economic consequences of hospitalizations for septicemia caused by Staphylococcus aureusin hemodialysis patients with ESRD. Methods:We conducted a retrospective analysis of data obtained from the US Renal Data System to determine lengths of stay and Medicare paid costs for index hospitalizations and episodes of care for patients with ESRD hospitalized with septicemia caused by S aureus. Factors associated with hospital length of stay and Medicare paid costs were examined in multivariate analysis. Results:A total of 11,572 patient admissions with septicemia caused by S aureuswere included; 20.7% of patients developed 1 or more complications. Average length of stay for the index admission was 13.0 days, and 11.8% of patients were readmitted within 12 weeks for care related to S aureus. Average Medicare cost for the index admission was $17,307. Average episodic cost of care, including the index hospitalization, outpatient visits, and readmissions related to S aureusduring the subsequent 12 weeks, was $20,067. S aureus—related complications were associated with greater episodic costs of care: no complications, $18,476; one complication, $25,804 (P< 0.05 versus no complications); and 2 or more complications, $32,102 (P< 0.05 versus no complications). In multivariate analysis, complications resulted in increased mean lengths of stay of 4 to 7 days, and complications were among the strongest predictors of total episodic costs. Conclusion:Patients with septicemia caused by S aureushad costly and lengthy hospitalizations, which frequently were associated with clinically and economically important complications, including hospital readmissions. more...
- Published
- 2005
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47. Clinical Outcomes and Costs Due to Staphylococcus aureusBacteremia Among Patients Receiving Long-Term Hemodialysis
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Engemann, John J., Friedman, Joëlle Y., Reed, Shelby D., Griffiths, Robert I., Szczech, Lynda A., Kaye, Keith S., Stryjewski, Martin E., Reller, L. Barth, Schulman, Kevin A., Corey, G. Ralph, and Fowler, Vance G. more...
- Abstract
AbstractObjective:To examine the clinical outcomes and costs associated with Staphylococcus aureusbacteremia among hemodialysis-dependent patients.Design:Prospectively identified cohort study.Setting:A tertiary-care university medical center in North Carolina.Patients:Two hundred ten hemodialysis-dependent adults with end-stage renal disease hospitalized with S. aureusbacteremia.Results:The majority of the patients (117; 55.7%) underwent dialysis via tunneled catheters, and 29.5% (62) underwent dialysis via synthetic arteriovenous fistulas. Vascular access was the suspected source of bacteremia in 185 patients (88.1%). Complications occurred in 31.0% (65), and the overall 12-week mortality rate was 19.0% (40). The mean cost of treating S. aureusbacteremia, including readmissions and outpatient costs, was $24,034 per episode. The mean initial hospitalization cost was significantly greater for patients with complicated versus uncomplicated S. aureusbacteremia ($32,462 vs $17,011; P= .002).Conclusion:Interventions to decrease the rate of S. aureusbacteremia are needed in this high-risk, hemodialysis-dependent population (Infect Control Hosp Epidemiol2005;26:534-539). more...
- Published
- 2005
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48. Costs and Outcomes Among Hemodialysis-Dependent Patients With Methicillin-Resistant or Methicillin-Susceptible Staphylococcus aureusBacteremia
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Reed, Shelby D., Friedman, Joëlle Y., Engemann, John J., Griffiths, Robert I., Anstrom, Kevin J., Kaye, Keith S., Stryjewski, Martin E., Szczech, Lynda A., Reller, L. Barth, Corey, G. Ralph, Schulman, Kevin A., and Fowler, Vance G. more...
- Abstract
AbstractObjective:Comorbid conditions have complicated previous analyses of the consequences of methicillin resistance for costs and outcomes of Staphylococcus aureusbacteremia. We compared costs and outcomes of methicillin resistance in patients with S. aureusbacteremia and a single chronic condition.Design, Setting, and Patients:We conducted a prospective cohort study of hemodialysis-dependent patients with end-stage renal disease and S. aureusbacteremia hospitalized between July 1996 and August 2001. We used propensity scores to reduce bias when comparing patients with methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) S. aureusbacteremia. Outcome measures were resource use, direct medical costs, and clinical outcomes at 12 weeks after initial hospitalization.Results:Fifty-four patients (37.8%) had MRSA and 89 patients (62.2%) had MSSA. Compared with patients with MSSA bacteremia, patients with MRSA bacteremia were more likely to have acquired the infection while hospitalized for another condition (27.8% vs 12.4%; P= .02). To attribute all inpatient costs to S. aureusbacteremia, we limited the analysis to 105 patients admitted for suspected S. aureusbacteremia from a community setting. Adjusted costs were higher for MRSA bacteremia for the initial hospitalization ($21,251 vs $13,978; P= .012) and after 12 weeks ($25,518 vs $17,354; P= .015). At 12 weeks, patients with MRSA bacteremia were more likely to die (adjusted odds ratio, 5.4; 95% confidence interval, 1.5 to 18.7) than were patients with MSSA bacteremia.Conclusions:Community-dwelling, hemodialysis-dependent patients hospitalized with MRSA bacteremia face a higher mortality risk, longer hospital stays, and higher inpatient costs than do patients with MSSA bacteremia. more...
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- 2005
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49. Importance sampling on coalescent histories. II: Subdivided population models
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De Iorio, Maria and Griffiths, Robert C.
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De Iorio and Griffiths (2004) developed a new method of constructing sequential importance-sampling proposal distributions on coalescent histories of a sample of genes for computing the likelihood of a type configuration of genes in the sample by simulation. The method is based on approximating the diffusion-process generator describing the distribution of population gene frequencies, leading to an approximate sample distribution and finally to importance-sampling proposal distributions. This paper applies that method to construct an importance-sampling algorithm for computing the likelihood of samples of genes in subdivided population models. The importance-sampling technique of Stephens and Donnelly (2000) is thus extended to models with a Markov chain mutation mechanism between gene types and migration of genes between subpopulations. An algorithm for computing the likelihood of a sample configuration of genes from a subdivided population in an infinitely-many-alleles model of mutation is derived, extending Ewens's (1972) sampling formula in a single population. Likelihood calculation and ancestral inference in gene trees constructed from DNA sequences under the infinitely-many-sites model are also studied. The Griffiths-Tavaré method of likelihood calculation in gene trees of Bahlo and Griffiths (2000) is improved for subdivided populations. more...
- Published
- 2004
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50. Abiotic controls on nitrogen fixation and respiration in selected woody debris from the Pacific Northwest, U.S.A.
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Hicks, William T., Harmon, Mark E., and Griffiths, Robert P.
- Abstract
AbstractWe estimated the effects of temperature, moisture, and oxygen concentration on nitrogen fixation and respiration in woody debris and used this information to model seasonal variation in these processes. We measured acetylene reduction and CO2evolution of wood samples to determine the relative effect of these abiotic factors on nitrogen fixation and respiration. The interactions of these abiotic factors were examined in a model to test whether temperature alone can be used as a predictor of seasonal changes in nitrogen fixation and respiration rates in woody debris. Nitrogen fixation rates were optimum near 30ºC, whereas respiration rates were optimum over a broader range, from 30°C to 50°C. Nitrogen fixation and respiration rates were greatest above 175% and 100% wood moisture content, respectively, with little activity below 50%. Nitrogen fixation was optimum at 2% O2, with activity much reduced above and below this concentration. Respiration was optimal when O2exceeded 1%. In our simulations, annual nitrogen fixation and respiration rates were 7.8 and 1.7 times greater, respectively, when only temperature limitation was included than when moisture and oxygen limitations were also included. Therefore, seasonal interactions of abiotic factors need to be considered when estimating annual nitrogen fixation and respiration rates. more...
- Published
- 2003
- Full Text
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