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A rectifying transformation is required to sense variations in texture contrast. Various theoretical and practical considerations have inclined researchers to suppose that this rectification is full-wave, rather than half-wave. In the studies reported here, observers are asked to judge which of two texture patches has higher texture variance. Textures are(More)
This paper investigates intensity coding in human vision. Specifically, we address the following question: how do different luminances influence the perceived total luminance of a composite image? We investigate this question using a paradigm in which the observer attempts to judge, with feedback, which of two texture patches has higher total luminance. All(More)
This work studies the preattentive discrimination of achromatic textures composed of mixtures of different (Weber) contrasts. These textures differ not at all in local spatial structure, but only in the relative proportions of different contrasts they comprise. It is shown that, like chromatic discrimination, preattentive discrimination of such textures is(More)
We investigated whether plaids activate preattentive mechanisms that are distinct from those activated by their component gratings. Observers searched for a target plaid, the sum of two perpendicular components in a circular window (radius = 0.65 degrees). The target was present on half the trials. On all trials, half of the distractors had the same(More)
BACKGROUND The characteristics and prognostic value of the variability of premature ventricular contraction (PVC) coupling intervals (CIs) for cardiac mortality are not yet decisive. METHODSANDRESULTS In 133 consecutive patients (58±14 years old, 53 women) who had left ventricular dysfunction (LVD: ejection fraction <50%) and frequent PVCs (≥10/h) who(More)
BACKGROUND The purpose of this study was to investigate the clinical usefulness of myocardial contrast echocardiography (MCE) to distinguish stress-induced cardiomyopathy (SCMP) from acute myocardial infarction (AMI) in the emergency department (ED). METHODS AND RESULTS We investigated 51 patients (62±13 years, 29 women) who had suspected SCMP in the ED(More)
Jong-Ho Nam, Chi Young Shim*, Darae Kim, Seung-Hyun Lee, and Geu-Ru Hong Cardiology Division, Severance Cardiovascular Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea; and Division of Cardiovascular Surgery, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul 03722,(More)
BACKGROUND AND OBJECTIVES Oxidative stress (OS) plays an important role in the pathophysiology of atrial fibrillation (AF) by amplifying the inflammatory cascade, wherein augmented inflammation facilitates the atrial electrical remodeling process. Few studies have investigated the possible link between systemic inflammation and OS in AF. SUBJECTS AND(More)