Surgical results: A justification of the surgeon selection process for the ACAS trial

AbstractPurpose: The selection of surgeons to participate in a prospective randomized trial comparing the efficacy of a surgical method with medical management is critically important because it will have a direct impact on the outcome of the study and the future use of the operation. We report the success of the method used for selecting surgeons who participated in the Asymptomatic Carotid Atherosclerosis Study (ACAS) by examining the surgical morbidity and mortality rates and the outcome of the study.Methods: A Surgical Management Committee established criteria for auditing surgeons who wished to participate in the study. The parameters included a minimum performance of at least 12 carotid endarterectomies (CEA) per year and an audit of each surgeon's last 50 consecutive CEAs with required documentation of a combined neurologic morbidity and mortality rate of <3.0% for asymptomatic patients and <5.0% for all indications including symptomatic patients.Results: As of February 1991, 164 surgeons from 48 medical centers applied for ACAS participation. One hundred seventeen were approved, and their aggregate experience of 5641 operations yielded a combined neurologic morbidity and mortality rate of 2.3% for asymptomatic and symptomatic patients combined. The morbidity and mortality rate for CEA on asymptomatic patients was 1.7%. These surgeons, plus those recruited after February 1991, became investigators in the ACAS trial and were responsible for the surgical care of 825 patients who were randomized to the surgical arm. Seven hundred twenty-four patients actually underwent CEA. One patient (0.14%) died and ten patients (1.38%) had strokes within the 30-day perioperative interval, for a combined stroke or death incidence of 1.52%. The 5-year stroke event rate in the surgical group (including perioperative morbidity and mortality rates) was 5.1%, compared with 11% of patients treated medically, yielding a relative risk reduction of 53% in favor of surgery ( p =0.004).Conclusions: A method for selecting surgeons for participation in the ACAS trial was successful in providing low perioperative morbidity and mortality rates. This materially influenced the outcome of the study in favor of CEA. (J VASC SURG 1996;23:323-8.

Hydrographic observations from the US/PRC Cooperative Program in the Western Equatorial Pacific Ocean, cruises 1-4

In support of the Tropical Oceans and Global Atmosphere (TOGA) program, investigators from Woods Hole Oceanographic Institution (WHOI), NOAA Pacific Marine Envionmental Laboratory and the State Oceanic Administration (SOA) from both Qingdao (First Institute) and Guangzhou (South China Sea Branch) conducted hydrographic observations aboard the Chinese Research vessels Xiang Yang Hong 5 and Xiang Yang Hong 14 in the western equatorial Pacific. The objective of this component of the TOGA program was to document the water mass property distributions of the western equatorial Pacific Ocean and describe the oceanic velocity field. The four cruises summarized here were conducted during the period November 1985 to June 1988 and are the first half of an eight cruise repeated survey of the region scheduled to be completed in spring 1990. Conductivity-Temperatue-Depth-Oxygen (CTD/02) stations were collected to a minimum cast depth of 2,500 m or the bottom when shallower. The cruises reoccupied the same stations to provide temporal information. Summarized listings of CTD/O2 data together with selected physical properties of sea water for these cruises are provided here, as well as a description of the hardware used and an explanation of the data reduction tehniques employed.Funding was provided by the National Oceanic and Atmospheric Administration

Behaviour of uranium along Jucar River (Eastern Spain) Determination of 234U/238U and 235U/238U ratios

The uranium concentration and the U-234/U-238, U-235/U-238 activity ratios were studied in water samples from Jucar River, using low-level alpha-spectrometry. The effects of pH, temperature and salinity were considered and more detailed sampling was done in the neighbourhood of Cofrentes Nuclear plant (Valencia, Spain). Changes were observed in the uranium concentration with the salinity and the U-234/U-238 activity ratio was found to vary with pH. Leaching and dilution, which depend on pH and salinity, are the probable mechanisms for these changes in the concentration of uranium and the activity ratios.Rodríguez Álvarez, MJ.; Sanchez, F. (1995). Behaviour of uranium along Jucar River (Eastern Spain) Determination of 234U/238U and 235U/238U ratios. Journal of Radioanalytical and Nuclear Chemistry. 190(1):113-120. doi:10.1007/BF02035642S1131201901M. J. RORDÍGUEZ-AALVAREZ, F. SÁNCHEZ, E. NAVARRO, Proc. 3nd Intern. Summer School, Huelva Spain, M. GARCÍA-LEÓN, G. MADURGA (Eds), World Scientific, Singapore, 1994.M. IVANOVICH, R. S. HARMON (Eds), Uranium Disequilibrium Series: Applications to Environmental Problems, Clarendon Press, Oxford, 1982.K. OSMOND, J. B. COWART, At. Energy Rev., 14 (1976) 621.B. L. DICKSON, R. L. MEAKINS, Nucl. Instrum. Methods Phys. Res., 223 (1983) 593.J. L. GASCÓN, MURILLO, PhD Thesis, University of Zaragoza, Spain, 1990.M. C. MORÓN, A. MARTINEZ-AGUIRRE, M. GARCÍA-LEÓN, Intern. Conf. on Environmental Radioactivity in the Mediterranean Area, Barcelona 10–13 May 1988, SNE-ENS, Barcelona, 1988, p. 111.R. BOJANOWSKI, R. FUKAI, S. BALLESTRA, H. ASARI, Determination of natural radioactive elements in marine environmental materials by ion-exchange and α-spectrometry. Proc. 4th Symp. on the Determination of Radionuclides in Environmental and Biological Materials, April 1983, London, Ed-Rd Press.R. GARCÍA-TENORIO, M. GARCÍA-LEÓN, G. PIAZZA, Anal. Física B, 82 (1986) 238.L. HALLSTADIUS, Nucl. Instrum. Methods Phys. Res., 223 (1984) 266.F. VERA, A. MARTIN, Nucl. Instrum. Methods Phys. Res., A276 (1989) 289.A. MARTINEZ-AGUIRRE, M. GARCÍA-LEÓN, J. Radioanal. Nucl. Chem., 155 (1991) 97.J. R. DOOLEY, H. C. ROSHOLT, Econ. Geol., 61 (1996) 326.A. MARTINEZ-AGUIRRE, M. GARCÍA-LEÓN, Radiat. Prot. Dosim., 45 (1992) 249.J. TOOLE, M. S. BAXTER, J. THOMSON, Estuarine, Coastal and Shelf Sci., 25 (1987) 283.S. G. BHAT, S. KRISHANASWAMI, Proc. Indian Acad. Sci., A LXX, (1969).K. K. TUREKIAN, J. K. COCHRAN, in: Chemical Oceanography, Vol. 7, J. P. RILEY and R. CHESTER (Eds), 2nd ed., Academic Press, New York, 1978.D. LANGMUIR, Geochim. Cosmochim. Acta, 42 (1978) 547.J. M. MARTIN, M. MEYBECK, Mar. Chem., 7 (1979) 173.Radionuclide Transformations, Annals of the ICRP, ICRP Publication 38, Vol. 11–13, Pergamon Press, 1983.A. MANGINI, G. SONNTAG, G. BERTSCH, E. MÜLLER, Nature, 278 (1979) 337.M. R. SCOTT, in: M. IVANOVICH, R. S. HARMON (Eds), Uranium Disequilibrium Series: Applications to Environmental Problems, Clarendon Press, Oxford, 1982.J. K. OSMOND, J. B. COWART, in: M. IVANOVICH, R. S. HARMON (Eds), Uranium Disequilibrium Series: Applications to Environmental Problems, Clarendon Press, Oxford, 1982.R. BOWEN (Eds), Isotopes in the Earth Sciences, Elsevier Applied Science, 1988.F. VERA, PhD Thesis, University Extremadura, Spain, 1988.F. VERA, A. MARTIN, J. Radioanal. Nucl. Chem., 134 (1988) 73

Assessment of pre- and post-methionine load homocysteine for prediction of recurrent stroke and coronary artery disease in the Vitamin Intervention for Stroke Prevention Trial

Methionine (Met) loading increases total plasma homocysteine (tHcy) and assesses homocysteine metabolism. We tested the hypothesis that pre- or post-Met tHcy will predict recurrent stroke or coronary artery disease (CAD) in a subgroup analysis of the Vitamin Intervention for Stroke Prevention (VISP) trial. VISP subjects with non-disabling stroke underwent measurement of tHcy at baseline (fasting pre- and post-Met load) and were randomized to high/low-dose B-vitamin therapy for prevention of recurrent stroke or CAD. In the sample cohort of 2,124 subjects, mean ± SD tHcy levels in µmol/L were: pre-Met 13.2 ± 4.3, post-Met 30.4 ± 9.76, and pre/post-Met Δ 17.1 ± 8.3. The hazard ratio (HR) for recurrent stroke was 1.16 (p=0.026) for 1 SD higher pre-Met tHcy and 1.15 (p=0.054) for 1 SD higher post-Met tHcy. For CAD, the HR for 1 SD higher pre-Met tHcy was 1.27 (p=0.001) and was 1.00 (p=0.99) for post-Met tHcy. In survival analyses using pre- or post-Met as covariates, the coefficient of pre/post-Met Δ was not significant for stroke and was only marginally significant for CAD (p<0.08), but was negative. We conclude that fasting, pre-Met tHcy is as effective as post-Met tHcy or pre/post-Met Δ in predicting the risk for stroke and CAD

Measurement of the Proton and Deuteron Spin Structure Functions g2 and Asymmetry A2

We have measured the spin structure functions g2p and g2d and the virtual photon asymmetries A2p and A2d over the kinematic range 0.02 < x < 0.8 and 1.0 < Q^2 < 30(GeV/c)^2 by scattering 38.8 GeV longitudinally polarized electrons from transversely polarized NH3 and 6LiD targets.The absolute value of A2 is significantly smaller than the sqrt{R} positivity limit over the measured range, while g2 is consistent with the twist-2 Wandzura-Wilczek calculation. We obtain results for the twist-3 reduced matrix elements d2p, d2d and d2n. The Burkhardt-Cottingham sum rule integral - int(g2(x)dx) is reported for the range 0.02 < x < 0.8.Comment: 12 pages, 4 figures, 1 tabl

Users' guides to the medical literature: how to use an article about mortality in a humanitarian emergency

The accurate interpretation of mortality surveys in humanitarian crises is useful for both public health responses and security responses. Recent examples suggest that few medical personnel and researchers can accurately interpret the validity of a mortality survey in these settings. Using an example of a mortality survey from the Democratic Republic of Congo (DRC), we demonstrate important methodological considerations that readers should keep in mind when reading a mortality survey to determine the validity of the study and the applicability of the findings to their settings

Mobile Phone Data for Children on the Move: Challenges and Opportunities

Today, 95% of the global population has 2G mobile phone coverage and the number of individuals who own a mobile phone is at an all time high. Mobile phones generate rich data on billions of people across different societal contexts and have in the last decade helped redefine how we do research and build tools to understand society. As such, mobile phone data has the potential to revolutionize how we tackle humanitarian problems, such as the many suffered by refugees all over the world. While promising, mobile phone data and the new computational approaches bring both opportunities and challenges. Mobile phone traces contain detailed information regarding people's whereabouts, social life, and even financial standing. Therefore, developing and adopting strategies that open data up to the wider humanitarian and international development community for analysis and research while simultaneously protecting the privacy of individuals is of paramount importance. Here we outline the challenging situation of children on the move and actions UNICEF is pushing in helping displaced children and youth globally, and discuss opportunities where mobile phone data can be used. We identify three key challenges: data access, data and algorithmic bias, and operationalization of research, which need to be addressed if mobile phone data is to be successfully applied in humanitarian contexts.Comment: 13 pages, book chapte

The CLIMODE field campaign : observing the cycle of convection and restratification over the Gulf Stream

Author Posting. © American Meteorological Society, 2009. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 90 (2009): 1337-1350, doi:10.1175/2009BAMS2706.1.A major oceanographic field experiment is described, which is designed to observe, quantify, and understand the creation and dispersal of weakly stratified fluid known as “mode water” in the region of the Gulf Stream. Formed in the wintertime by convection driven by the most intense air–sea fluxes observed anywhere over the globe, the role of mode waters in the general circulation of the subtropical gyre and its biogeo-chemical cycles is also addressed. The experiment is known as the CLIVAR Mode Water Dynamic Experiment (CLIMODE). Here we review the scientific objectives of the experiment and present some preliminary results.Physical Oceanography program of NS

Precision Determination of the Neutron Spin Structure Function g1n

We report on a precision measurement of the neutron spin structure function $g^n_1$ using deep inelastic scattering of polarized electrons by polarized ^3He. For the kinematic range 0.014<x<0.7 and 1 (GeV/c)^2< Q^2< 17 (GeV/c)^2, we obtain $\int^{0.7}_{0.014} g^n_1(x)dx = -0.036 \pm 0.004 (stat) \pm 0.005 (syst)$ at an average $Q^2=5 (GeV/c)^2$. We find relatively large negative values for $g^n_1$ at low $x$. The results call into question the usual Regge theory method for extrapolating to x=0 to find the full neutron integral $\int^1_0 g^n_1(x)dx$, needed for testing quark-parton model and QCD sum rules.Comment: 5 pages, 3 figures To be published in Phys. Rev. Let