Discrete choice models with capacity constraints: an empirical analysis of the housing market of the greater Paris region

Discrete choice models are based on the idea that each user can choose both freely and independently from other users in a given set of alternatives. But this is not the case in several situations. In particular, limitations and interactions can occur when the number of available products of one type is smaller than the total demand for this type. As a consequence, some individuals can be denied their preferred choice. We develop a methodology to address those constraints and we apply it to residential location choice, where our empirical data suggest that availability constraints may bias actual choices. The analysis provides some theoretical developments and elaborates an iterative procedure for estimating demand in the presence of capacity constraints. The empirical application relies on the location choice model developed and estimated in [6] for Ile de France (Paris region) and generalizes it to integrate capacity constraints.Residential location, constrained Logit, capacity constraints, sampling, Ilede- France

Evolutionary history of LINE-1 in the major clades of placental mammals

BACKGROUND: LINE-1 constitutes an important component of mammalian genomes. It has a dynamic evolutionary history characterized by the rise, fall and replacement of subfamilies. Most data concerning LINE-1 biology and evolution are derived from the human and mouse genomes and are often assumed to hold for all placentals. METHODOLOGY: To examine LINE-1 relationships, sequences from the 3′ region of the reverse transcriptase from 21 species (representing 13 orders across Afrotheria, Xenarthra, Supraprimates and Laurasiatheria) were obtained from whole genome sequence assemblies, or by PCR with degenerate primers. These sequences were aligned and analysed. PRINCIPAL FINDINGS: Our analysis reflects accepted placental relationships suggesting mostly lineage-specific LINE-1 families. The data provide clear support for several clades including Glires, Supraprimates, Laurasiatheria, Boreoeutheria, Xenarthra and Afrotheria. Within the afrotherian LINE-1 (AfroLINE) clade, our tree supports Paenungulata, Afroinsectivora and Afroinsectiphillia. Xenarthran LINE-1 (XenaLINE) falls sister to AfroLINE, providing some support for the Atlantogenata (Xenarthra+Afrotheria) hypothesis. SIGNIFICANCE: LINEs and SINEs make up approximately half of all placental genomes, so understanding their dynamics is an essential aspect of comparative genomics. Importantly, a tree of LINE-1 offers a different view of the root, as long edges (branches) such as that to marsupials are shortened and/or broken up. Additionally, a robust phylogeny of diverse LINE-1 is essential in testing that site-specific LINE-1 insertions, often regarded as homoplasy-free phylogenetic markers, are indeed unique and not convergent

New Insights into Rental Housing Markets across the United States: Web Scraping and Analyzing Craigslist Rental Listings

Current sources of data on rental housing - such as the census or commercial databases that focus on large apartment complexes - do not reflect recent market activity or the full scope of the U.S. rental market. To address this gap, we collected, cleaned, analyzed, mapped, and visualized 11 million Craigslist rental housing listings. The data reveal fine-grained spatial and temporal patterns within and across metropolitan housing markets in the U.S. We find some metropolitan areas have only single-digit percentages of listings below fair market rent. Nontraditional sources of volunteered geographic information offer planners real-time, local-scale estimates of rent and housing characteristics currently lacking in alternative sources, such as census data.Comment: 20 pages, 9 figures, Journal of Planning Education and Research. 2016. Online firs

UrbanSim2: Simulating the Connected Metropolis

UrbanSim is an open source software platform for agent-based geospatial simulation, focusing on the spatial dynamics of urban development. Since its creation UrbanSim has been used in the official planning processes for at least a dozen regional governments which were used to help allocate billions of dollars in regional investments in transportation infrastructure. UrbanSim was first conceptualized in the late 1990’s and implemented using the Java programming language. The technology landscape for scientific computing changed dramatically after that, and by 2005 UrbanSim was converted to Python, making heavy use of Numpy to vectorize calculations. By 2014, it became clear that UrbanSim should be reimplemented again to take advantage of significant advances in the libraries available for scientific Python. The new version of UrbanSim, called UrbanSim2, makes extensive use of community-supported scientific Python libraries to reduce the amount of domain-specific customized code to a minimum. UrbanSim is an excellent case study for the power of leveraging the work of the scientific programming community as scaffolding for a domain-specific application, as opposed to building an extensive customized solution in each domain. Additionally, the open and participatory nature inherent in nearly all of the open source projects described here has been particularly embraced by governments, who are often reticent to support large commercial institutions and balkanized and private data formats and software tools

Stopping the UN’s Agenda 21 policy on sustainable development has become a rallying cry for the Tea Party across the U.S.

In recent years the United Nation’s Agenda 21 policy has become the rallying cry for many in the Tea Party who believe that the U.N. threatens American sovereignty. This concern led the introduction of anti-Agenda 21 legislation in 26 states in 2012 and 2013. Karen Trapenberg Frick, David Weinzimmer and Paul Waddell find that conservative states were more likely to see the introduction of anti-Agenda 21 legislation. They writes that the widespread outbreak of introducing legislation may indicate a longer-term situation whereby sustainability opposition becomes part of the state agenda with continued public discussion and media attention. In light of this, planning communities must consider new methods of public engagement that encourages genuine dialogue

A model of residential location choice with endogenous housing prices and traffic for the Paris region

There is a growing interest in the development and the use of large-scale planning models. In this paper, we describe the first step of a project to integrate UrbanSim, a dynamic microsimulation land use model, and METROPOLIS, a dynamic traffic model. This is the first attempt, to our knowledge, to integrate a dynamic land use model and a dynamic traffic model. We briefly describe the two models and propose a unified framework for their integration. Within this integrated framework we develop a model of residential location choice, with endogenous housing prices and traffic. The study area for this research is the Ile-de-France (Paris region), for which we provide empirical results

trans-Dibromidobis(triphenyl­phosphane)platinum(II) chloro­form monosolvate

Both the platininum complex and the solvent mol­ecule of the title compound, [PtBr2(C18H15P)2]·CHCl3, are located on a twofold rotation axis. The CH unit and the Cl atoms of the CHCl3 mol­ecule are disordered over two equally occupied positions. The complex shows a trans square-planar geometry about the Pt atom