On a common circle: natural scenes and Gestalt rules

To understand how the human visual system analyzes images, it is essential to know the structure of the visual environment. In particular, natural images display consistent statistical properties that distinguish them from random luminance distributions. We have studied the geometric regularities of oriented elements (edges or line segments) present in an ensemble of visual scenes, asking how much information the presence of a segment in a particular location of the visual scene carries about the presence of a second segment at different relative positions and orientations. We observed strong long-range correlations in the distribution of oriented segments that extend over the whole visual field. We further show that a very simple geometric rule, cocircularity, predicts the arrangement of segments in natural scenes, and that different geometrical arrangements show relevant differences in their scaling properties. Our results show similarities to geometric features of previous physiological and psychophysical studies. We discuss the implications of these findings for theories of early vision.Comment: 3 figures, 2 large figures not include

Time Marches on, and So Does the History of Public Relations

Editor's Introduction to History of Public Relations special issu

Quadrupole Collective States in a Large Single-J Shell

We discuss the ability of the generator coordinate method (GCM) to select collective states in microscopic calculations. The model studied is a single-$j$ shell with hamiltonian containing the quadrupole-quadrupole interaction. Quadrupole collective excitations are constructed by means of the quadrupole single-particle operator. Lowest collective bands for $j$=31/2 and particle numbers $N$=4,6,8,10,12, and $14$ are found. For lower values of $j$, exact solutions are obtained and compared with the GCM results.Comment: submitted for publication in Phys. Rev. C, revtex, 28 pages, 15 PostScript figures available on request from [email protected], preprint No. IFT/17/9

Feed-Forward Segmentation of Figure-Ground and Assignment of Border-Ownership

Figure-ground is the segmentation of visual information into objects and their surrounding backgrounds. Two main processes herein are boundary assignment and surface segregation, which rely on the integration of global scene information. Recurrent processing either by intrinsic horizontal connections that connect surrounding neurons or by feedback projections from higher visual areas provide such information, and are considered to be the neural substrate for figure-ground segmentation. On the contrary, a role of feedforward projections in figure-ground segmentation is unknown. To have a better understanding of a role of feedforward connections in figure-ground organization, we constructed a feedforward spiking model using a biologically plausible neuron model. By means of surround inhibition our simple 3-layered model performs figure-ground segmentation and one-sided border-ownership coding. We propose that the visual system uses feed forward suppression for figure-ground segmentation and border-ownership assignment

Failure of available scoring systems to predict ongoing infection in patients with abdominal sepsis after their initial emergency laparotomy

<p>Abstract</p> <p>Background</p> <p>To examine commonly used scoring systems, designed to predict overall outcome in critically ill patients, for their ability to select patients with an abdominal sepsis that have ongoing infection needing relaparotomy.</p> <p>Methods</p> <p>Data from a RCT comparing two surgical strategies was used. The study population consisted of 221 patients at risk for ongoing abdominal infection. The following scoring systems were evaluated with logistic regression analysis for their ability to select patients requiring a relaparotomy: APACHE-II score, SAPS-II, Mannheim Peritonitis Index (MPI), MODS, SOFA score, and the acute part of the APACHE-II score (APS).</p> <p>Results</p> <p>The proportion of patients requiring a relaparotomy was 32% (71/221). Only 2 scores had a discriminatory ability in identifying patients with ongoing infection needing relaparotomy above chance: the APS on day 1 (AUC 0.61; 95%CI 0.52-0.69) and the SOFA score on day 2 (AUC 0.60; 95%CI 0.52-0.69). However, to correctly identify 90% of all patients needing a relaparotomy would require such a low cut-off value that around 80% of all patients identified by these scoring systems would have negative findings at relaparotomy.</p> <p>Conclusions</p> <p>None of the widely-used scoring systems to predict overall outcome in critically ill patients are of clinical value for the identification of patients with ongoing infection needing relaparotomy. There is a need to develop more specific tools to assist physicians in their daily monitoring and selection of these patients after the initial emergency laparotomy.</p> <p>Trial registration number</p> <p>ISRCTN: <a href="http://www.controlled-trials.com/ISRCTN 51729393">ISRCTN 51729393</a></p

How Awareness Changes the Relative Weights of Evidence During Human Decision-Making

A combined behavioral and brain imaging study shows how sensory awareness and stimulus visibility can influence the dynamics of decision-making in humans

Initial microbial spectrum in severe secondary peritonitis and relevance for treatment

This study aims to determine whether abdominal microbial profiles in early severe secondary peritonitis are associated with ongoing infection or death. The study is performed within a randomized study comparing two surgical treatment strategies in patients with severe secondary peritonitis (n = 229). The microbial profiles of cultures retrieved from initial emergency laparotomy were tested with logistic regression analysis for association with ‘ongoing infection needing relaparotomy’ and in-hospital death. No microbial profile or the presence of yeast or Pseudomonas spp. was related to the risk of ongoing infection needing relaparotomy. Resistance to empiric therapy for gram positive cocci and coliforms was moderately associated with ongoing abdominal infection (OR 3.43 95%CI 0.95–12.38 and OR 7.61, 95%CI 0.75–76.94). Presence of only gram positive cocci, predominantly Enterococcus spp, was borderline independently associated with in-hospital death (OR 3.69, 95%CI 0.99–13.80). In secondary peritonitis microbial profiles do not predict ongoing abdominal infection after initial emergency laparotomy. However, the moderate association of ongoing infection with resistance to the empiric therapy compels to more attention for resistance when selecting empiric antibiotic coverage

Factors associated with posttraumatic stress symptoms in a prospective cohort of patients after abdominal sepsis: a nomogram

Objective: To determine to what extent patients who have survived abdominal sepsis suffer from symptoms of posttraumatic stress disorder (PTSD) and depression, and to identify potential risk factors for PTSD symptoms. Design and setting: PTSD and depression symptoms were measured using the Impact of Events Scale-Revised (IES-R), the Post-Traumatic Symptom Scale 10 (PTSS-10) and the Beck Depression Inventory II (BDI-II). Patients and participants: A total of 135 peritonitis patients were eligible for this study, of whom 107 (80%) patients completed the questionnaire. The median APACHE-II score was 14 (range 12-16), and 89% were admitted to the ICU. Measurements and results: The proportion of patients with "moderate" PTSD symptom scores was 28% (95% CI 20-37), whilst 10% (95% CI 6-17) of patients had "high" PTSD symptom scores. Only 5% (95% CI 2-12) of the patients expressed severe depression symptoms. Factors associated with increased PTSD symptoms in a multivariate ordinal regression model were younger age (0.74 per 10 years older, p = 0.082), length of ICU stay (OR = 1.4 per doubling of duration, p = 0.003) and having some (OR = 4.9, p = 0.06) or many (OR = 55.5, p < 0.001) traumatic memories of the ICU or hospital stay. Conclusion: As many as 38% of patients after abdominal sepsis report elevated levels of PTSD symptoms on at least one of the questionnaires. Our nomogram may assist in identifying patients at increased risk for developing symptoms of PTSD

Dos and don’ts in response priming research

Response priming is a well-understood but sparsely employed paradigm in cognitive science. The method is powerful and well-suited for exploring early visuomotor processing in a wide range of tasks and research fields. Moreover, response priming can be dissociated from visual awareness, possibly because it is based on the first sweep of feedforward processing of primes and targets. This makes it a theoretically interesting device for separating conscious and unconscious vision. We discuss the major opportunities of the paradigm and give specific recommendations (e.g., tracing the time-course of priming in parametric experiments). Also, we point out typical confounds, design flaws, and data processing artifacts

Determinants of lenalidomide response with or without erythropoiesis-stimulating agents in myelodysplastic syndromes:the HOVON89 trial

A randomized phase-II study was performed in low/int-1 risk MDS (IPSS) to study efficacy and safety of lenalidomide without (arm A) or with (arm B) ESA/G-CSF. In arm B, patients without erythroid response (HI-E) after 4 cycles received ESA; G-CSF was added if no HI-E was obtained by cycle 9. HI-E served as primary endpoint. Flow cytometry and next-generation sequencing were performed to identify predictors of response. The final evaluation comprised 184 patients; 84% non-del(5q), 16% isolated del(5q); median follow-up: 70.7 months. In arm A and B, 39 and 41% of patients achieved HI-E; median time-to-HI-E: 3.2 months for both arms, median duration of-HI-E: 9.8 months. HI-E was significantly lower in non-del(5q) vs. del(5q): 32% vs. 80%. The same accounted for transfusion independency-at-week 24 (16% vs. 67%), but similar in both arms. Apart from presence of del(5q), high percentages of bone marrow lymphocytes and progenitor B-cells, a low number of mutations, absence of ring sideroblasts, and SF3B1 mutations predicted HI-E. In conclusion, lenalidomide induced HI-E in patients with non-del(5q) and del(5q) MDS without additional effect of ESA/G-CSF. The identified predictors of response may guide application of lenalidomide in lower-risk MDS in the era of precision medicine. (EudraCT 2008-002195-10).</p