4,719 research outputs found

    Summing Radiative Corrections to the Effective Potential

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    When one uses the Coleman-Weinberg renormalization condition, the effective potential VV in the massless ϕ44\phi_4^4 theory with O(N) symmetry is completely determined by the renormalization group functions. It has been shown how the (p+1)(p+1) order renormalization group function determine the sum of all the N^{\mbox{\scriptsize p}}LL order contribution to VV to all orders in the loop expansion. We discuss here how, in addition to fixing the N^{\mbox{\scriptsize p}}LL contribution to VV, the (p+1)(p+1) order renormalization group functions also can be used to determine portions of the N^{\mbox{\scriptsize p+n}}LL contributions to VV. When these contributions are summed to all orders, the singularity structure of \mcv is altered. An alternate rearrangement of the contributions to VV in powers of lnϕ\ln \phi, when the extremum condition V(ϕ=v)=0V^\prime (\phi = v) = 0 is combined with the renormalization group equation, show that either v=0v = 0 or VV is independent of ϕ\phi. This conclusion is supported by showing the LL, \cdots, N4^4LL contributions to VV become progressively less dependent on ϕ\phi.Comment: 16 pages; added 2 figures and 2 tables; references revise

    New Loop Representations for 2+1 Gravity

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    Since the gauge group underlying 2+1-dimensional general relativity is non-compact, certain difficulties arise in the passage from the connection to the loop representations. It is shown that these problems can be handled by appropriately choosing the measure that features in the definition of the loop transform. Thus, ``old-fashioned'' loop representations - based on ordinary loops - do exist. In the case when the spatial topology is that of a two-torus, these can be constructed explicitly; {\it all} quantum states can be represented as functions of (homotopy classes of) loops and the scalar product and the action of the basic observables can be given directly in terms of loops.Comment: 28pp, 1 figure (postscript, compressed and uuencoded), TeX, Pennsylvania State University, CGPG-94/5-

    P E N G A R U H K O M P E N S A S I D A N D I S I P L I N K E R J A T E R H A D A P K I N E R J A G U R U D I S M A N 1 J A T I S A R I K A B U P A T E N K A R A W A N G

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    A B S T R A K P e n e l i t i a n i n i b e r t u j u a n u n t u k m e n g e t a h u i p e m b e r i a n K o m p e n s a s i , k o n d i s i D i s i p l i n K e r j a d a n K i n e r j a G u r u , s e r t a u n t u k m e n g e t a h u i s e b e r a p a b e s a r p e n g a r u h v a r i a b e l K o m p e n s a s i d a n D i s i p l i n K e r j a t e r h a d a p K i n e r j a G u r u b a i k s e c a r a s i m u l t a n m a u p u n s e c a r a p a r s i a l d i S M A N e g e r i 1 J a t i s a r i K a b u p a t e n K a r a w a n g . S a m p e l d a l a m p e n e l i t i a n i n i j u m l a h s e l u r u\ud h p o p u l a s i y a n g b e r j u m l a h 4 9 G u r u . M e t o d e p e n e l i t i a n y a n g d i g u n a k a n a d a l a h a n a l i s i s r e g r e s i b e r g a n d a , a n a l i s i s k o r e l a s i b e r g a n d a , a n a l i s i s k o e f i s i e n d e t e r m i n a s i s i m u l t a n d a n p a r s i a l . H a s i l p e n e l i t i a n m e n u n j u k k a n b a h w a k o m p e n s a s i y a n g d i b e r i k a n m a s i h t e r m a s u k k a t e g o r i c u k u p , m e n g e n a i d i s i p l i n k e r j a s e c a r a u m u m r e s p o n d e n m e n y a t a k a n d a l a m k a t e g o r i c u k u p , d a n k i n e r j a g u r u b e r a d a p a d a k a t e g o r i c u k u p . K o m p e n s a s i d a n D i s i p l i n K e r j a s e c a r a s i m u l t a n m a u p u n p a r s i a l b e r p e n g a r u h s i g n i f i k a n t e r h a d a p K i n e r j a g u r u . S e c a r a s i m u l t a n p e n g a r u h n y a a d a l a h 8 1 , 9 % d a n s i s a n y a 1 8 , 1 % d i p e n g a r u h i o l e h v a r i a b e l l a i n . V a r i a b e l y a n g b e r p e n g a r u h d o m i n a n a d a l a h K o m p e n s a s i . K a t a K u n c i : K o m p e n s a s i , D i s i p l i n K e r j a , d a n K i n e r j a G u r

    Riociguat for the treatment of chronic thromboembolic pulmonary hypertension.

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    BACKGROUND: Riociguat, a member of a new class of compounds (soluble guanylate cyclase stimulators), has been shown in previous clinical studies to be beneficial in the treatment of chronic thromboembolic pulmonary hypertension. METHODS: In this phase 3, multicenter, randomized, double-blind, placebo-controlled study, we randomly assigned 261 patients with inoperable chronic thromboembolic pulmonary hypertension or persistent or recurrent pulmonary hypertension after pulmonary endarterectomy to receive placebo or riociguat. The primary end point was the change from baseline to the end of week 16 in the distance walked in 6 minutes. Secondary end points included changes from baseline in pulmonary vascular resistance, N-terminal pro-brain natriuretic peptide (NT-proBNP) level, World Health Organization (WHO) functional class, time to clinical worsening, Borg dyspnea score, quality-of-life variables, and safety. RESULTS: By week 16, the 6-minute walk distance had increased by a mean of 39 m in the riociguat group, as compared with a mean decrease of 6 m in the placebo group (least-squares mean difference, 46 m; 95% confidence interval [CI], 25 to 67; P<0.001). Pulmonary vascular resistance decreased by 226 dyn · sec · cm-5in the riociguat group and increased by 23 dyn · sec · cm-5in the placebo group (least-squares mean difference, -246 dyn · sec · cm-5; 95% CI, -303 to -190; P<0.001). Riociguat was also associated with significant improvements in the NT-proBNP level (P<0.001) and WHO functional class (P = 0.003). The most common serious adverse events were right ventricular failure (in 3% of patients in each group) and syncope (in 2% of the riociguat group and in 3% of the placebo group). CONCLUSIONS: Riociguat significantly improved exercise capacity and pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension. (Funded by Bayer HealthCare; CHEST-1 and CHEST-2 ClinicalTrials.gov numbers, NCT00855465 and NCT00910429, respectively.) Copyright © 2013 Massachusetts Medical Society
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