The role of cognitive abilities in laparoscopic simulator training

Learning minimally invasive surgery (MIS) differs substantially from learning open surgery and trainees differ in their ability to learn MIS. Previous studies mainly focused on the role of visuo-spatial ability (VSA) on the learning curve for MIS. In the current study, the relationship between spatial memory, perceptual speed, and general reasoning ability, in addition to VSA, and performance on a MIS simulator is examined. Fifty-three laparoscopic novices were tested for cognitive aptitude. Laparoscopic performance was assessed with the LapSim simulator (Surgical Science Ltd., Gothenburg, Sweden). Participants trained multiple sessions on the simulator until proficiency was reached. Participants showed significant improvement on the time to complete the task and efficiency of movement. Performance was related to different cognitive abilities, depending on the performance measure and type of cognitive ability. No relationship between cognitive aptitude and duration of training or steepness of the learning curve was found. Cognitive aptitude mediates certain aspects of performance during training on a laparoscopic simulator. Based on the current study, we conclude that cognitive aptitude tests cannot be used for resident selection but are potentially useful for developing individualized training programs. More research will be performed to examine how cognitive aptitude testing can be used to design training programs

Criticality in Dynamic Arrest: Correspondence between Glasses and Traffic

Dynamic arrest is a general phenomenon across a wide range of dynamic systems, but the universality of dynamic arrest phenomena remains unclear. We relate the emergence of traffic jams in a simple traffic flow model to the dynamic slow down in kinetically constrained models for glasses. In kinetically constrained models, the formation of glass becomes a true (singular) phase transition in the limit $T\to 0$. Similarly, using the Nagel-Schreckenberg model to simulate traffic flow, we show that the emergence of jammed traffic acquires the signature of a sharp transition in the deterministic limit \pp\to 1, corresponding to overcautious driving. We identify a true dynamical critical point marking the onset of coexistence between free flowing and jammed traffic, and demonstrate its analogy to the kinetically constrained glass models. We find diverging correlations analogous to those at a critical point of thermodynamic phase transitions.Comment: 4 pages, 4 figure

London's King's Cross redevelopment: a compact, resource efficient and 'liveable' global city model for an era of climate emergency?

Cities have long been subject to urban containment policies against urban sprawl. Climate change concerns have recently added to the imperative to densify urban space. Urban compaction is often pursued through the creation of ‘exemplar’ urban developments that superficially implement ‘best practice’ ideas from elsewhere. In this paper, we abandon the notion of ‘best practice’ in favour of context-sensitive ‘good practices’. Taking London’s King’s Cross redevelopment as a case study, this paper draws on qualitative methods to examine the contribution of context and path-dependency, as a product of local and non-local forces, to the emergence of King´s Cross as ‘good practice’

Annoyance from transportation noise: relationships with exposure metrics DNL and DENL and their confidence intervals.

We present a model of the distribution of noise annoyance with the mean varying as a function of the noise exposure. Day-night level (DNL) and day-evening-night level (DENL) were used as noise descriptors. Because the entire annoyance distribution has been modeled, any annoyance measure that summarizes this distribution can be calculated from the model. We fitted the model to data from noise annoyance studies for aircraft, road traffic, and railways separately. Polynomial approximations of relationships implied by the model for the combinations of the following exposure and annoyance measures are presented: DNL or DENL, and percentage "highly annoyed" (cutoff at 72 on a scale of 0-100), percentage "annoyed" (cutoff at 50 on a scale of 0-100), or percentage (at least) "a little annoyed" (cutoff at 28 on a scale of 0-100). These approximations are very good, and they are easier to use for practical calculations than the model itself, because the model involves a normal distribution. Our results are based on the same data set that was used earlier to establish relationships between DNL and percentage highly annoyed. In this paper we provide better estimates of the confidence intervals due to the improved model of the relationship between annoyance and noise exposure. Moreover, relationships using descriptors other than DNL and percentage highly annoyed, which are presented here, have not been established earlier on the basis of a large dataset

Cytoplasmic Linker Proteins: Keeping in Shape by Regulating the Cytoskeleton

Microtubules are an essential component of the eukaryotic cytoskeleton. Proper functioning of the microtubular network depends highly on its dynamic properties, with frequent transitions from phases of prolonged growth to rapid shrinkage (catastrophe) and vice versa (rescue). Several proteins have been shown to bind to microtubules, some of them, the so-called plus-end-tracking proteins (+TIPs), binding specifically to the growing ends of microtubules. This thesis describes the functional analysis of two +TIPs, the Cytoplasmic Linker Proteins CLIP-115 and CLIP-170. These proteins are structurally highly similar resulting in a high level of redundancy. Although single CLIP-115 or CLIP-170 knockout mice both have characteristic features, no large abnormalities were found in fibroblasts derived from them. To learn more about the CLIPs and their redundant functions, CLIP double knockout (DKO) mice were generated. The dynamic properties of the microtubules in ce! lls derived from these mice were profoundly altered with a five-fold decrease in rescue-frequency. In addition, the microtubule network was changed notably, with large microtubule-free areas in which proteins aggregates were found. These aggregates contained the microtubule motor-protein cytoplasmic dynein and several components of the dynactin complex. Furthermore DKO fibroblasts spread abnormally, resulting in a two-fold increase of the surface area in attached cells compared to wild type cells. The mice deficient for both CLIP-115 and CLIP-170 have an abnormal posture and show hind limb clasping. Although they perform poorly on certain behavioral and strength-related tasks, they show a surprising age-related improvement of motor coordination. At older ages, certain tasks start to deteriorate again. Using magnetic resonance imaging (MRI) and histological analysis a progressive form of hydrocephalus is detected. In younger mice, an accumulation of cerebellar neurons is see! n in other parts of the brain, indicating a defect in neuronal migrati on. Taken together, the results described in this thesis confirm that CLIP-115 and CLIP-170 act as rescue factors, but that they also have important functions in regulating cell spreading and neuronal migration

Environmental and Energy Performance of the Biomass to Synthetic Natural Gas Supply Chain

A quarter of the total primary energy demand in the European Union is met by natural gas. Synthetic natural gas produced through biomass gasification can contribute to a more sustainable energy supply system. A chain analysis of the energetic performance of synthetic natural gas where the upstream, midstream and downstream part are included has not been found in literature. The energy performance of the possible large-scale application of synthetic natural gas is therefore unsure. A model was designed to analyse the performance of the biomass to synthetic natural gas chain and to estimate the effect of 1% synthetic natural gas in the energy system. A break-even distance is introduced to determine whether it is energetically feasible to apply pretreatment. Results show that torrefaction and pelleting are energetically unfeasible within the European Union. Emissions can be reduced with almost 70% compared to a fossil reference scenario. Over 1.2 Mha is required to fulfil 0.25% of the total primary energy demand in the European Union