Holistic processing of impossible objects: Evidence from Garner’s speeded-classification task

Holistic processing, the decoding of the global structure of a stimulus while the local parts are not explicitly represented, is a basic characteristic of object perception. The current study was aimed to test whether such a representation could be created even for objects that violate fundamental principles of spatial organization, namely impossible objects. Previous studies argued that these objects cannot be represented holistically in long-term memory because they lack coherent 3D structure. Here, we utilized Garner’s speeded classification task to test whether the perception of possible and impossible objects is mediated by similar holistic processing mechanisms. To this end, participants were asked to make speeded classifications of one object dimension while an irrelevant dimension was kept constant (baseline condition) or when this dimension varied (filtering condition). It is well accepted that ignoring the irrelevant dimension is impossible when holistic perception is mandatory, thus the extent of Garner interference in performance between the baseline and filtering conditions serves as an index of holistic processing. Critically, in Experiment 1, similar levels of Garner interference were found for possible and impossible objects implying holistic perception of both object types. Experiment 2 extended these results and demonstrated that even when depth information was explicitly processed, participants were still unable to process one dimension (width/depth) while ignoring the irrelevant dimension (depth/width, respectively). The results of Experiment 3 replicated the basic pattern found in Experiments 1 and 2 using a novel set of object exemplars. In Experiment 4, we used possible and impossible versions of the Penrose triangles in which information about impossibility is embedded in the internal elements of the objects which participant were explicitly asked to judge. As in Experiments 1–3, similar Garner interference was found for possible and impossible objects. Taken together, these findings emphasize the centrality of holistic processing style in object perception and suggest that it applies even for atypical stimuli such as impossible objects.     

Selective Laser Sintering 3-Dimensional Printing as a Single Step Process to Prepare Amorphous Solid Dispersion Dosage Forms for Improved Solubility and Dissolution Rate

This study reports the development of ritonavir-copovidone amorphous solid dispersions (ASDs) and dosage forms thereof using selective laser sintering (SLS) 3-dimensional (3-D) printing in a single step, circumventing the post-processing steps required in common techniques employed to make ASDs. For this study, different drug loads of ritonavir with copovidone were processed at varying processing conditions to understand the impact, range, and correlation of these parameters for successful ASD formation. Further, ASDs characterized using conventional and advanced solid-state techniques including wide-angle X-ray scattering (WAXS), solid-state nuclear magnetic resonance (ssNMR), revealed the full conversion of the crystalline drug to its amorphous form as a function of laser-assisted selective fusion in a layer-by-layer manner. It was observed that an optimum combination of the powder flow properties, surface temperature, chamber temperature, laser speed, and hatch spacing was crucial for successful ASD formation, any deviations resulted in print failures or only partial amorphous conversion. Moreover, a 21-fold increase in solubility was demonstrated by the SLS 3-D printed tablets. The results confirmed that SLS 3-D printing can be used as a single-step platform for creating ASD-based pharmaceutical dosage forms with a solubility advantage.     

Does selective migration bias the health impact assessment of urban regeneration programmes in cross-sectional studies? Findings from a Dutch case study

We examined if the assessment of the health impact of a national Dutch regeneration programme depends on using either a repeated cross-sectional or longitudinal study design. This is important as only the latter design can incorporate migration patterns. For both designs, we compared trends in medication use between target and control districts. We found differences in medication use trends to be modest under the longitudinal design, and not demonstrable under the repeated cross-sectional design. The observed differences were hardly influenced by migration patterns. We conclude that in the Netherlands migration patterns had little effect on the health impact assessment of this national urban regeneration programme, so either the cross-sectional or longitudinal evaluation study design will do.     

“Open” approach to aortic arch aneurysm repair

Aortic arch aneurysm is a relatively rare entity in cardiac surgery. Repair of such aneurysms, either in isolation or combined with other cardiac procedures, remains a challenging task. The need to produce a relatively bloodless surgical field with circulatory arrest, while at the same time protecting the brain, is the hallmark of this challenge. However, a clear understanding of the topic allows a better and less morbid approach to such a complex surgery.Literature has shown the advantage of selective cerebral perfusion techniques in comparison with only circulatory arrest. Ability to perfuse the brain has allowed circulatory arrest temperatures at moderate hypothermia without the need for deep hypothermia. Even though cannulation site selection appears to be a minor issue, literature has shown that the subclavian/axillary route has the best outcomes and that femoral cannulation should only be reserved for no access patients. Although different techniques for arch anastomosis have been described, we routinely perform the distal first technique as we find it to be less cumbersome and easiest to reproduce.In this review our aim is to outline a systematic approach to aortic arch surgery. Starting with indications for intervention and proceeding with approaches on site of cannulation, approaches to brain protection with hypothermia and selective cerebral perfusion and finally surgical steps in performing the distal and arch vessels anastomosis.     

cN0甲状腺乳头状癌颈淋巴结选择性清除术的意义及方式探讨

目的探讨甲状腺乳头状癌颈淋巴结转移规律,为选择最佳手术方式提供参考。方法回顾性分析2012年1月~2016年1月宁德市闽东医院618例诊断为c N0甲状腺乳头状癌患者的临床和病理资料,术前、术中腺体内注射美蓝,切除甲状腺同时常规清扫中央区,根据淋巴结染色情况选择性清扫颈侧区。结果 618例有完整统计资料的c N0甲状腺乳头状癌患者中,病理诊断颈部蓝染淋巴结总转移率为88.19%(3347/3795),中央区(Ⅵ区)淋巴结转移率为89.49%(3006/3359),颈侧区(Ⅱ、Ⅲ、Ⅳ)蓝染淋巴结转移率为78.21%(341/436),其中Ⅱ区72.81%(83/114)、Ⅲ区80.46%(140/174)、Ⅳ区79.73%(118/148)。结论甲状腺乳头状癌最常见的转移部位是Ⅵ区,术中应常规清除,其次依次为Ⅲ、Ⅳ、Ⅱ、Ⅴ区,对于c N0患者也应选择性行颈部淋巴结清扫术,美蓝进行术前标记转移淋巴结方法可行,对于临床术式选择有一定的指导意义,值得推广应用。     

The acquisition of contextual cueing effects by persons with and without intellectual disability

Two experiments were conducted to compare the acquisition of contextual cueing effects of adolescents and young adults with intellectual disabilities (ID) relative to typically developing children and young adults. Contextual cueing reflects an implicit, memory based attention guidance mechanism that results in faster search for target locations that have been previously experienced in a predictable context. In the study, participants located a target stimulus embedded in a context of numerous distracter stimuli. During a learning phase, the location of the target was predictable from the location of the distracters in the search displays. We then compared response times to locating predictable relative to unpredictable targets presented in a test phase. In Experiment 1, all of the distracters predicted the location of the target. In Experiment 2, half of the distracters predicted the location of the target while the other half varied randomly. The participants with ID exhibited significant contextual facilitation in both experiments, with the magnitude of facilitation being similar to that of the typically developing (TD) children and adults. We concluded that deficiencies in contextual cueing are not necessarily associated with low measured intelligence that results in a classification of ID.