Complexity for extended dynamical systems

We consider dynamical systems for which the spatial extension plays an important role. For these systems, the notions of attractor, epsilon-entropy and topological entropy per unit time and volume have been introduced previously. In this paper we use the notion of Kolmogorov complexity to introduce, for extended dynamical systems, a notion of complexity per unit time and volume which plays the same role as the metric entropy for classical dynamical systems. We introduce this notion as an almost sure limit on orbits of the system. Moreover we prove a kind of variational principle for this complexity.Comment: 29 page

Assessing protocol adherence in a clinical trial with ordered treatment regimens: Quantifying the pragmatic, randomized optimal platelet and plasma ratios (PROPPR) trial experience

AbstractBackgroundMedication dispensing errors are common in clinical trials, and have a significant impact on the quality and validity of a trial. Therefore, the definition, calculation and evaluation of such errors are important for supporting a trial’s conclusions. A variety of medication dispensing errors can occur. In this paper, we focus on errors in trials where the intervention includes multiple therapies that must be given in a pre-specified order that varies across treatment arms and varies in duration.MethodsThe Pragmatic, Randomized Optimal Platelet and Plasma Ratios (PROPPR) trial was a Phase III multi-site, randomized trial to compare the effectiveness and safety of 1:1:1 transfusion ratios of plasma and platelets to red blood cells with a 1:1:2 ratio. In this trial, these three types of blood products were to be transfused in a pre-defined order that differed by treatment arm. In this paper, we present approaches from the PROPPR trial that we used to define and calculate the occurrence of out of order blood transfusion errors. We applied the proposed method to calculate protocol adherence to the specified order of transfusion in each treatment arm.ResultsUsing our proposed method, protocol adherence was greater in the 1:1:1 group than in the 1:1:2 group (96% vs 93%) (p<0.0001), although out of order transfusion errors in both groups were low. Final transfusion ratios of plasma to platelets to red blood cells for the 1:1:1 ratio group was 0.93:1.32:1, while the transfusion ratio for the 1:1:2 ratio group was 0.48:0.48:1.ConclusionsOverall, PROPPR adherence to blood transfusion order pre-specified in the protocol was high, and the required order of transfusions for the 1:1:2 group was more difficult to achieve. The approaches proposed in this manuscript were useful in evaluating the PROPPR adherence and are potentially useful for other trials where a specific treatment orders with varying durations must be maintained

Sarcopenic Obesity and Myosteatosis Are Associated with Higher Mortality in Patients with Cirrhosis

Background and aims Obesity is frequently associated with cirrhosis, and cirrhotic patients may develop simultaneous loss of skeletal muscle and gain of adipose tissue, culminating in the condition of sarcopenic obesity. Additionally, muscle depletion is characterized by both a reduction in muscle size and increased proportion of muscular fat, termed myosteatosis. In this study, we aimed to establish the frequency and clinical significance of sarcopenia, sarcopenic obesity and myosteatosis in cirrhotic patients. Methods We analysed 678 patients with cirrhosis. Sarcopenia, sarcopenic obesity and myosteatosis were analysed by CT scan using the third lumbar vertebrae skeletal muscle and attenuation indexes, using previously validated gender-and body mass index-specific cutoffs. Results Patients were predominately men (n = 457, 67%), and cirrhosis aetiology was hepatitis C virus in 269 patients (40%), alcohol in 153 (23%), non-alcoholic steatohepatitis/cryptogenic in 96 (14%), autoimmune liver disease in 55 (8%), hepatitis B virus in 43 (6%), and others in 5 patients (1%). Sarcopenia was present in 292 (43%), 135 had sarcopenic obesity (20%) and 353 had myosteatosis (52%). Patients with sarcopenia (22 ± 3 vs. 95 ± 22 months, P = 0.04) were associated with mortality. Conclusions Sarcopenia, sarcopenic obesity and myosteatosis are often present in patients with cirrhosis, and sarcopenia and myosteatosis are independently associated with a higher long-term mortality in cirrhosis

Uniformity in the Wiener-Wintner theorem for nilsequences

We prove a uniform extension of the Wiener-Wintner theorem for nilsequences due to Host and Kra and a nilsequence extension of the topological Wiener-Wintner theorem due to Assani. Our argument is based on (vertical) Fourier analysis and a Sobolev embedding theorem.Comment: v3: 18 p., proof that the cube construction produces compact homogeneous spaces added, measurability issues in the proof of Theorem 1.5 addressed. We thank the anonymous referees for pointing out these gaps in v

Structure of the Polycomb Group Protein PCGF1 in Complex with BCOR Reveals Basis for Binding Selectivity of PCGF Homologs

SummaryPolycomb-group RING finger homologs (PCGF1, PCGF2, PCGF3, PCGF4, PCGF5, and PCGF6) are critical components in the assembly of distinct Polycomb repression complex 1 (PRC1)-related complexes. Here, we identify a protein interaction domain in BCL6 corepressor, BCOR, which binds the RING finger- and WD40-associated ubiquitin-like (RAWUL) domain of PCGF1 (NSPC1) and PCGF3 but not of PCGF2 (MEL18) or PCGF4 (BMI1). Because of the selective binding, we have named this domain PCGF Ub-like fold discriminator (PUFD). The structure of BCOR PUFD bound to PCGF1 reveals that (1) PUFD binds to the same surfaces as observed for a different Polycomb group RAWUL domain and (2) the ability of PUFD to discriminate among RAWULs stems from the identity of specific residues within these interaction surfaces. These data show the molecular basis for determining the binding preference for a PCGF homolog, which ultimately helps determine the identity of the larger PRC1-like assembly

Higher media multi-tasking activity is associated with smaller gray-matter density in the anterior cingulate cortex

Media multitasking, or the concurrent consumption of multiple media forms, is increasingly prevalent in today’s society and has been associated with negative psychosocial and cognitive impacts. Individuals who engage in heavier media-multitasking are found to perform worse on cognitive control tasks and exhibit more socio-emotional difficulties. However, the neural processes associated with media multi-tasking remain unexplored. The present study investigated relationships between media multitasking activity and brain structure. Research has demonstrated that brain structure can be altered upon prolonged exposure to novel environments and experience. Thus, we expected differential engagements in media multitasking to correlate with brain structure variability. This was confirmed via Voxel-Based Morphometry (VBM) analyses: Individuals with higher Media Multitasking Index (MMI) scores had smaller gray matter density in the anterior cingulate cortex (ACC). Functional connectivity between this ACC region and the precuneus was negatively associated with MMI. Our findings suggest a possible structural correlate for the observed decreased cognitive control performance and socio-emotional regulation in heavy media-multitaskers. While the cross-sectional nature of our study does not allow us to specify the direction of causality, our results brought to light novel associations between individual media multitasking behaviors and ACC structure differences

Academic Performance and Behavioral Patterns

Identifying the factors that influence academic performance is an essential part of educational research. Previous studies have documented the importance of personality traits, class attendance, and social network structure. Because most of these analyses were based on a single behavioral aspect and/or small sample sizes, there is currently no quantification of the interplay of these factors. Here, we study the academic performance among a cohort of 538 undergraduate students forming a single, densely connected social network. Our work is based on data collected using smartphones, which the students used as their primary phones for two years. The availability of multi-channel data from a single population allows us to directly compare the explanatory power of individual and social characteristics. We find that the most informative indicators of performance are based on social ties and that network indicators result in better model performance than individual characteristics (including both personality and class attendance). We confirm earlier findings that class attendance is the most important predictor among individual characteristics. Finally, our results suggest the presence of strong homophily and/or peer effects among university students

The Rise and Fall of "Respectable" Spanish Liberalism, 1808-1923: An Explanatory Framework

The article focuses on the reasons behind both the consolidation of what I have termed “respectable” liberalism between the 1830s and the 1840s and its subsequent decline and fall between 1900 and 1923. In understanding both processes I study the links established between “respectable” liberals and propertied elites, the monarchy, and the Church. In the first phase these links served to consolidate the liberal polity. However, they also meant that many tenets of liberal ideology were compromised. Free elections were undermined by the operation of caciquismo, monarchs established a powerful position, and despite the Church hierarchy working with liberalism, the doctrine espoused by much of the Church was still shaped by the Counter-Reformation. Hence, “respectable” liberalism failed to achieve a popular social base. And the liberal order was increasingly denigrated as part of the corrupt “oligarchy” that ruled Spain. Worse still, between 1916 and 1923 the Church, monarch, and the propertied elite increasingly abandoned the liberal Monarchist Restoration. Hence when General Primo de Rivera launched his coup the rug was pulled from under the liberals’ feet and there was no one to cushion the fall

Real-Time, Real World Learning—Capitalising on Mobile Technology

This chapter explores the adoption of Web 2.0 technologies to promote active learning by students and to both mediate and enhance classroom instruction. Web 2.0 refers to open source, web-enabled applications (apps) that are driven by user-manipulated and user-generated content (Kassens-Noor, 2012). These apps are often rich in user participation, have dynamic content, and harness the collective intelligence of users (Chen, Hwang, & Wang, 2012). As such, these processes create “active, context based, personalised learning experiences” (Kaldoudi, Konstantinidis, & Bamidis, 2010, p. 130) that prioritise learning ahead of teaching. By putting the learner at the centre of the education process educators can provide environments that enhance employability prospects and spark a passion for learning that, hopefully, lasts a lifetime. As such, we critique an active learning approach that makes use of technology such as mobile applications (apps), Twitter, and augmented reality to enhance students’ real world learning. Dunlap and Lowenthal (2009) argue that social media can facilitate active learning as they recreate informal, free-flowing communications that allow students and academics to connect on a more emotional level. Furthermore, their use upskills students in the technical complexities of the digital world and also the specialised discourses that are associated with online participation, suitable for real world learning and working (Fig. 16.1). Three case studies explore the benefits of Web 2.0 processes. The first details the use of Twitter chats to connect students, academics, and industry professionals via online synchronous discussions that offer a number of benefits such as encouraging concise writing from students and maintaining on-going relationships between staff, students, and industry contacts. The second details a location-based mobile app that delivers content to students when they enter a defined geographical boundary linked to an area of a sports precinct. Finally, we explore the use of augmented reality apps to enhance teaching in Human Geography and Urban Studies