Evaluation of the optical criteria for sessile serrated lesions of the colon: A prospective study on a colorectal cancer screening population

Background and study aims We aimed to describe the presence and combination of Hazewinkelʼs optical diagnosis (OD) criteria for sessile serrated lesions (SSL), determining which lesion characteristics increase the probability of a correct OD, with a focus on diminutive lesions. Patients and methods This was a prospective study describing the presence of Hazewinkelʼs OD criteria for SSL in lesions found in consecutive CRC screening colonoscopies. The presence of each OD criterion and their diagnostic combinations in SSL, related to the lesion’s NBI International Colorectal Endoscopic (NICE) classification category, size, and location, were described. The presence of two or more optical criteria was considered diagnostic of SSL. The OD was compared to pathology as the gold standard. Results Seventy-nine SSLs (5.6 %) were diagnosed. Cloud-like appearance was the most prevalent OD criterion (35, 44.3 %). OD criteria were more frequently identified in NICE type 1, ≥ 10 mm, and proximal lesions. Only 26 SLLs fulfilled the OD criteria (sensitivity 32.9 %, 95 % CI 29.1 %–36.7 %). The sensitivity for diminutive SSL was 14.7 %, (95 % CI 11.9 %–17.6 %). Eighty-five lesions were optically diagnosed as SSL. However, only in 26 SSL was this the definitive diagnosis (positive predictive value 30.6 %, 95 % CI 26.9 %–34.3 %). Size > 5 mm and proximal location increased the probability of a correct diagnosis. The overall accuracy of the optical criteria was 92.0 % (95 % CI, 89.8 %–94.2 %). Conclusions The Hazewinkelʼs optical criteria are not reliable for a positive diagnosis of SSL, particularly for diminutive lesions.

Unraveling the role of governance mechanisms in online ratings: The case of Spanish chain-affiliated hotels

This article studies how the choice of the mechanism of governance affects online ratings of hotels, empirically exploring the conditions under which various governance mechanisms improve (or damage) them. We emphasize that no governance mode is universally superior. However, when the mechanism of governance fits hotel characteristics, online ratings improve. We argue that such characteristics (i.e., hotel category, size, and age) determine the severity of agency problems (e.g., managerial shirking and free-riding) and the performance of governance choice. We test several organizational fit hypotheses on a data set of 2,328 hotels operating in Spain. Our results support the fit argument, because they show the superiority of franchise and management contracts (i.e., hybrids) for enhancing online ratings, as opposed to vertical integration, when category rises and size increases. Furthermore, we find evidence that maintenance does not appear to be a major problem in leasing. JEL CLASSIFICATION: D23; L25; L83

Recognition Memory Shielded from Semantic but not Perceptual Interference in Normal Aging

Normal aging impairs long-term declarative memory, and evidence suggests that this impairment may be driven partly by structural or functional changes in the medial temporal lobe (MTL). Theories of MTL memory function therefore make predictions for age-related memory loss. One theory – the Representational-Hierarchical account – makes two specific predictions. First, recognition memory in older participants should be impaired by feature-level interference, in which studied items contain many shared perceptual features such that those features appear repeatedly. Second, if the interference in a recognition memory task – i.e., the information that repeats across items – resides at a higher level of complexity than simple perceptual features, such as semantic gist, older adults should be less impacted by such interference than young adults. We tested these predictions using the Deese-Roediger-McDermott paradigm, by creating feature-level (i.e., perceptual) interference with phonemically/orthographically related word categories, and higher-level associative interference with semantically related word categories. Importantly, we manipulated category size in order to compare the effect of less versus more interference (i.e., small versus large category size), which served to (1) avoid potential item confounds arising from systematic differences between words belonging to perceptually- versus semantically-related categories, and (2) ensure that any effect of interference was due to information encoded at study, rather than pre-experimentally. Further, we used signal detection theory to interpret our data, rather than examining false alarm rates in isolation, thereby avoiding potentially confounding contamination of the memory measure by changes in response bias across conditions or groups. Older participants, relative to young adults, were relatively more impaired by perceptual interference and less impaired by semantic interference. This pattern seems at odds with many current theories of age-related memory loss, but is in line with the Representational-Hierarchical account.

Multi-Criteria Sorting with Category Size Restrictions

We consider the multi-criteria sorting problem where alternatives that are evaluated on multiple criteria are assigned into ordered categories. We focus on the sorting problem with category size restrictions, where the decision maker (DM) may have some concerns or constraints on the number of alternatives that should be assigned to some of the categories. We develop an approach based on the UTADIS method that fits an additive utility function to represent the decision maker’s preferences. We introduce additional variables and constraints to enforce the restrictions on the sizes of categories. The new formulation reduces the number of binary variables and hence decreases the computational effort compared to the existing approaches in the literature. We further improve the computational efficiency by developing lower and upper bounds on the rank of each alternative in order to narrow down the set of categories that each alternative can be assigned to. We demonstrate our approach on two applications from practice.