180 research outputs found

    CLASSICAL CEPHEID LIGHT CURVES REVISITED

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    Fourier decompositions are made of the B, V, R, and I classical Cepheid observations of Moffett and Barnes. The Fourier diagrams for V agree very well with the corresponding plots of Simon and Lee. The B, R, and I diagrams resemble the plots for V, but with small, systematic shifts in the phases ϕ21 and ϕ31. The 2.5-day star, DT Cyg, is confirmed as a likely overtone pulsator by its anomalous position in the Fourier plots. Finally, we study the Fourier phase quantity ϕ41 and introduce phase-phase diagrams to look at the Hertzsprung progression. Discontinuities in these diagrams support the idea that the long-period and short-period Cepheids may reach their limit cycles in different ways

    Cepheid variables in the LMC cluster NGC 1866. I. New BVRI CCD photometry

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    We report BV(RI)c CCD photometric data for a group of seven Cepheid variables in the young, rich cluster NGC 1866 in the Large Magellanic Cloud. The photometry was obtained as part of a program to determine accurate distances to these Cepheids by means of the infrared surface brightness technique, and to improve the LMC Cepheid database for constructing Cepheid PL and PLC relations. Using the new data together with data from the literature, we have determined improved periods for all variables. For five fundamental mode pulsators, the light curves are now of excellent quality and will lead to accurate distance and radius determinations once complete infrared light curves and radial velocity curves for these variables become available.Comment: To appear in ApJ Supp., AASTeX, 24 pages, 8 tables, 8 figure

    V(RI)sub(c) Photometry of Cepheids in the Magellanic Clouds

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    We present V(RI)sub data for thirteen Cepheids in the Large Magellanic Cloud ans fifty-five in each wavelength band. The median uncertainty in the photometry iy Moffett, Gieren & Barnes (1998) which contained 1000 measures (±0.01\pm 0.01 mag) in each wavelength band on 22 variables with periods in the range 8--133 days.Comment: LaTeX file (9 pages), LaTeX table (1 page), 2 figures of 3 panels eacs PASP (July

    Synthalin::a lost lesson for glucagon suppression in diabetes therapeutics

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    Objectives Within mammalian pancreatic islets, there are two major endocrine cell types, beta-cells which secrete insulin and alpha-cells which secrete glucagon. Whereas, insulin acts to lower circulating glucose, glucagon counters this by increasing circulating glucose via the mobilisation of glycogen. Synthalin A (Syn A) was the subject of much research in the 1920s and 1930s as a potential pancreatic alpha-cell toxin to block glucagon secretion. However, with the discovery of insulin and its lifesaving use in patients with diabetes, research on Syn-A was discontinued. Key findings This short review looks back on early studies performed with Syn A in animals and humans with diabetes. These are relevant today because both type 1 and type 2 diabetes are now recognised as states of not only insulin deficiency but also glucagon excess. Summary Lessons learned from this largely forgotten portfolio of work and therapeutic strategy aimed at limiting the number or function of islet alpha-cells might be worthy of reconsideration

    Impact of a Multimodal Antimicrobial Stewardship Program on Pseudomonas aeruginosa Susceptibility and Antimicrobial Use in the Intensive Care Unit Setting

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    Objective. To study the impact of our multimodal antibiotic stewardship program on Pseudomonas aeruginosa susceptibility and antibiotic use in the intensive care unit (ICU) setting. Methods. Our stewardship program employed the key tenants of published antimicrobial stewardship guidelines. These included prospective audits with intervention and feedback, formulary restriction with preauthorization, educational conferences, guidelines for use, antimicrobial cycling, and de-escalation of therapy. ICU antibiotic use was measured and expressed as defined daily doses (DDD) per 1,000 patient-days. Results. Certain temporal relationships between antibiotic use and ICU resistance patterns appeared to be affected by our antibiotic stewardship program. In particular, the ICU use of intravenous ciprofloxacin and ceftazidime declined from 148 and 62.5 DDD/1,000 patient-days to 40.0 and 24.5, respectively, during 2004 to 2007. An increase in the use of these agents and resistance to these agents was witnessed during 2008–2010. Despite variability in antibiotic usage from the stewardship efforts, we were overall unable to show statistical relationships with P. aeruginosa resistance rate. Conclusion. Antibiotic resistance in the ICU setting is complex. Multimodal stewardship efforts attempt to prevent resistance, but such programs clearly have their limits

    Acupuncture for chronic neck pain: a pilot for a randomised controlled trial

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    Background: Acupuncture is increasingly being used for many conditions including chronic neck pain. However the evidence remains inconclusive, indicating the need for further well-designed research. The aim of this study was to conduct a pilot randomised controlled parallel arm trial, to establish key features required for the design and implementation of a large-scale trial on acupuncture for chronic neck pain. Methods: Patients whose GPs had diagnosed neck pain were recruited from one general practice, and randomised to receive usual GP care only, or acupuncture ( up to 10 treatments over 3 months) as an adjunctive treatment to usual GP care. The primary outcome measure was the Northwick Park Neck Pain Questionnaire (NPQ) at 3 months. The primary analysis was to determine the sample size for the full scale study. Results: Of the 227 patients with neck pain identified from the GP database, 28 (12.3%) consenting patients were eligible to participate in the pilot and 24 (10.5%) were recruited to the trial. Ten patients were randomised to acupuncture, receiving an average of eight treatments from one of four acupuncturists, and 14 were randomised to usual GP care alone. The sample size for the full scale trial was calculated from a clinically meaningful difference of 5% on the NPQ and, from this pilot, an adjusted standard deviation of 15.3%. Assuming 90% power at the 5% significance level, a sample size of 229 would be required in each arm in a large-scale trial when allowing for a loss to follow-up rate of 14%. In order to achieve this sample, one would need to identify patients from databases of GP practices with a total population of 230,000 patients, or approximately 15 GP practices roughly equal in size to the one involved in this study (i.e. 15,694 patients). Conclusion: This pilot study has allowed a number of recommendations to be made to facilitate the design of a large-scale trial, which in turn will help to clarify the existing evidence base on acupuncture for neck pain

    Acute kidney disease and renal recovery : consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup

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    Consensus definitions have been reached for both acute kidney injury (AKI) and chronic kidney disease (CKD) and these definitions are now routinely used in research and clinical practice. The KDIGO guideline defines AKI as an abrupt decrease in kidney function occurring over 7 days or less, whereas CKD is defined by the persistence of kidney disease for a period of > 90 days. AKI and CKD are increasingly recognized as related entities and in some instances probably represent a continuum of the disease process. For patients in whom pathophysiologic processes are ongoing, the term acute kidney disease (AKD) has been proposed to define the course of disease after AKI; however, definitions of AKD and strategies for the management of patients with AKD are not currently available. In this consensus statement, the Acute Disease Quality Initiative (ADQI) proposes definitions, staging criteria for AKD, and strategies for the management of affected patients. We also make recommendations for areas of future research, which aim to improve understanding of the underlying processes and improve outcomes for patients with AKD
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