Critical O(d)O(d)-equivariant biharmonic maps

We study $O(d)$-equivariant biharmonic maps in the critical dimension. A major consequence of our study concerns the corresponding heat flow. More precisely, we prove that blowup occurs in the biharmonic map heat flow from $B^4(0, 1)$ into $S^4$. To our knowledge, this was the first example of blowup for the biharmonic map heat flow. Such results have been hard to prove, due to the inapplicability of the maximum principle in the biharmonic case. Furthermore, we classify the possible $O(4)$-equivariant biharmonic maps from $\mathbf{R}^4$ into $S^4$, and we show that there exists, in contrast to the harmonic map analogue, equivariant biharmonic maps from $B^4(0,1)$ into $S^4$ that wind around $S^4$ as many times as we wish. We believe that the ideas developed herein could be useful in the study of other higher-order parabolic equations.Comment: 24 pages, 1 figure. Published online in Calculus of Variations and Partial Differential Equations, 201

Complexity in daily life – a 3D-visualization showing activity patterns in their contexts

This article attacks the difficulties to make well informed empirically grounded descriptions and analyses of everyday life activity patterns. At a first glance, everyday life seems to be very simple and everybody has experiences from it, but when we try to investigate it from a scientific perspective, its complexity is overwhelming. There are enormous variations in interests and activity patterns among individuals, between households and socio-economic groups in the population. Therefore, and in spite of good intentions, traditional methods and means to visualize and analyze often lead to over-simplifications. The aim of this article is to present a visualization method that might inspire social scientists to tackle the complexity of everyday life from a new angle, starting with a visual overview of the individual's time use in her daily life, subsequently aggregating to time use in her household, further at group and population levels without leaving the individual out of sight. Thereby variations and complexity might be treated as assets in the interpretation rather than obstacles. To exemplify the method we show how activities in a daily life project are distributed among household members and between men and women in a population.household division of labour, time-geography, 3D method, visualization, diaries, everyday life, activity patterns. Complexity in daily life – a 3D-visualization showing activity patterns in their contexts

Exploring time diaries using semi-automated activity pattern extraction

Identifying patterns of activities in time diaries in order to understand the variety of daily life in terms of combinations of activities performed by individuals in different groups is of interest in time use research. So far, activity patterns have mostly been identified by visually inspecting representations of activity data or by using sequence comparison methods, such as sequence alignment, in order to cluster similar data and then extract representative patterns from these clusters. Both these methods are sensitive to data size, pure visual methods become too cluttered and sequence comparison methods become too time consuming. Furthermore, the patterns identified by both methods represent mostly general trends of activity in a population, while detail and unexpected features hidden in the data are often never revealed. We have implemented an algorithm that searches the time diaries and automatically extracts all activity patterns meeting user-defined criteria of what constitutes a valid pattern of interest for the user’s research question. Amongst the many criteria which can be applied are a time window containing the pattern, minimum and maximum occurrences of the pattern, and number of people that perform it. The extracted activity patterns can then be interactively filtered, visualized and analyzed to reveal interesting insights. Exploration of the results of each pattern search may result in new hypotheses which can be subsequently explored by altering the search criteria. To demonstrate the value of the presented approach we consider and discuss sequential activity patterns at a population level, from a single day perspective.Time-geography, diaries, everyday life, activity patterns, visualization, data mining, sequential pattern mining

Obscenity and the Mail: A Study of Administrative Restraint

This paper shows how 3-dimensional interactive visualization can be used as a tool in system identification. Non-linear or time-dependent dynamics often leave a significant residual with linear, time-invariant models. The structure of this residual is decisive for the subsequent modelling, and by using advanced visualization techniques, the modeller may gain a deeper insight into this structure than can be obtained by standard correlation analysis

Optogenetic control of genetically-targeted pyramidal neuron activity in prefrontal cortex

A salient feature of prefrontal cortex organization is the vast diversity of cell types that support the temporal integration of events required for sculpting future responses. A major obstacle in understanding the routing of information among prefrontal neuronal subtypes is the inability to manipulate the electrical activity of genetically defined cell types over behaviorally relevant timescales and activity patterns. To address these constraints, we present here a simple approach for selective activation of prefrontal excitatory neurons in both in vitro and in vivo preparations. Rat prelimbic pyramidal neurons were genetically targeted to express a light-­activated nonselective cation channel, channelrhodopsin-­2, or a light-­driven inward chloride pump, halorhodopsin, which enabled them to be rapidly and reversibly activated or inhibited by pulses of light. These light responsive tools provide a spatially and temporally precise means of studying how different cell types contribute to information processing in cortical circuits. Our customized optrodes and optical commutators for in vivo recording allow for efficient light delivery and recording and can be requested at www.neuro-­cloud.net/nature-precedings/baratta

SCHOOL OF SERVICE: EFFECTS OF SCHOOL-ORIENTED DEVELOPMENT TYPOLOGY ON LOCAL CIVIC AND POLITICAL ENGAGEMENT

The school-oriented development hypothesis developed by Carolyn Reid and Emily Talen has thus far been tested only in suburban neighbourhoods. This study attempts to ascertain the impact of various design elements of the school-oriented development hypothesis on political and civic participation in the Homewood community in Pittsburgh, using a mixed methodology. Only one of the public schools in the study demonstrated a significant impact on political and civic participation in the surrounding blocks, and though this school also best followed the physical criteria of the school-oriented development typology, none of the other data warranted a conclusion favourable to the school-oriented development hypothesis. At the same time, however, greater attention must be paid to factors such as homeownership, whose effects were much greater and more significant than the presence of schools, and to the academic programmes in each school, which have the most direct impact on students and on the community as a whole. Greater communication between academic, design and community institutions is highly recommended

The Role of Positive Comity in U.S. Antitrust Enforcement Against Japanese Firms: A Mixed Review

On October 7, 1999, the United States and Japan signed an antitrust cooperation agreement. The agreement contains provisions for notification and consultation, coordination and cooperation, and positive comity. These provisions address Japanese sovereignty concerns arising from the unilateral application of U.S. antitrust laws to the conduct of Japanese firms that occurs outside the territorial borders of the United States. The agreement also addresses U.S. perceptions that Japanese markets are closed to American businesses because it offers tools, other than unilateral antitrust enforcement, to open Japanese markets to American businesses. However, the positive comity provision does not proscribe unilateral antitrust enforcement. This Comment analyzes the strengths and weaknesses of the positive comity provision and recommends several improvements