Measuring segregation using patterns of daily travel behavior : a social interaction based model of exposure

Recent advances in transportation geography demonstrate the ability to compute a metropolitan scale metric of social interaction opportunities based on the time-geographic concept of joint accessibility. The method we put forward in this article decomposes the social interaction potential (SIP) metric into interactions within and between social groups, such as people of different race, income level, and occupation. This provides a novel metric of exposure, one of the fundamental spatial dimensions of segregation. In particular, the SIP metric is disaggregated into measures of inter-group and intra-group exposure. While activity spaces have been used to measure exposure in the geographic literature, these approaches do not adequately represent the dynamic nature of the target populations. We make the next step by representing both the source and target population groups by space-time prisms, thus more accurately representing spatial and temporal dynamics and constraints. Additionally, decomposition of the SIP metric means that each of the group-wise components of the SIP metric can be represented at zones of residence, workplace, and specific origin-destination pairs. Consequently, the spatial variation in segregation can be explored and hotspots of segregation and integration potential can be identified. The proposed approach is demonstrated for synthetic cities with different population distributions and daily commute flow characteristics, as well as for a case study of the Detroit-Warren-Livonia MSA

Calculations of isobaric phase enthalpy differences for binary systems from vapor-liquid equilibrium data

Equations relating isobaric vapor-liquid equilibrium data to heats of vaporization are useful in testing the thermodynamic consistency of experimental VLE data and in the design of distillation equipment. Several researchers have proposed such equations based on the Gibbs-Duhem equation. At low pressures, simplified versions of these equations were successfully used to test the consistency of published VLE and enthalpy data. At high pressures, equilibrium phase enthalpy differences were calculated from rigorous equations using a modified form of the Redlich-Kwong equation to calculate fugacity coefficients. As expected, the relative error of using the simplified equations was found to increase with increasing pressure

A review of the use of a systematic observation method in coaching research between 1997-2016

© 2016 Informa UK Limited, trading as Taylor & Francis Group. A systematic observation method has been one of the most popularly employed methods in coaching research. Kahan’s review of this method conducted between 1975 and 1997 highlighted the key trends in this research, and offered methodological guidance for researchers wishing to use this method in their research. The purpose of this review was to provide an update of the use of a systematic observation method in coaching research and assess the extent to which the calls made by Kahan have been addressed. While in some respect this field of study has progressed (i.e., the introduction of qualitative methods), researchers adopting this method have failed to attend to many of the issues Kahan raised. For this method to continue to make a positive contribution towards the coaching research literature, researchers need to more critically reflect on how and why they are employing this method. At present, some of the decisions made by researchers who have conducted work in this area are not justified with a rationale. It is our intention that this review will serve as guidance for researchers and practitioners, and editors and reviewers of journals when attempting to assess the quality of this type of work

Visualisation and Quantification of Morphogen Gradient Formation in the Zebrafish

During embryonic development, signalling molecules known as morphogens act in a concentration-dependent manner to provide positional information to responding tissues. In the early zebrafish embryo, graded signalling by members of the nodal family induces the formation of mesoderm and endoderm, thereby patterning the embryo into three germ layers. Nodal signalling has also been implicated in the establishment of the dorso-ventral axis of the embryo. Although one can infer the existence of nodal gradients by comparing gene expression patterns in wild-type embryos and embryos in which nodal signalling is diminished or augmented, real understanding can only come from directly observing the gradients. One approach is to determine local ligand concentrations in the embryo, but this is technically challenging, and the presence of inhibitors might cause the effective concentration of a ligand to differ from its actual concentration. We have therefore taken two approaches to visualise a direct response to nodal signalling. In the first, we have used transgenic embryos to study the nuclear accumulation of a Smad2-Venus fusion protein, and in the second we have used bimolecular fluorescence complementation to visualise the formation of a complex between Smad2 and Smad4. This has allowed us to visualise, in living embryos, the formation of a graded distribution of nodal signalling activity. We have quantified the formation of the gradient in time and space, and our results not only confirm that nodal signalling patterns the embryo into three germ layers, but also shed light on its role in patterning the dorso-ventral axis and highlight unexpected complexities of mesodermal patterning

A language for mathematical knowledge management

We argue that the language of Zermelo Fraenkel set theory with definitions and partial functions provides the most promising bedrock semantics for communicating and sharing mathematical knowledge. We then describe a syntactic sugaring of that language that provides a way of writing remarkably readable assertions without straying far from the set-theoretic semantics. We illustrate with some examples of formalized textbook definitions from elementary set theory and point-set topology. We also present statistics concerning the complexity of these definitions, under various complexity measures