Dense point sets have sparse Delaunay triangulations

The spread of a finite set of points is the ratio between the longest and shortest pairwise distances. We prove that the Delaunay triangulation of any set of n points in R^3 with spread D has complexity O(D^3). This bound is tight in the worst case for all D = O(sqrt{n}). In particular, the Delaunay triangulation of any dense point set has linear complexity. We also generalize this upper bound to regular triangulations of k-ply systems of balls, unions of several dense point sets, and uniform samples of smooth surfaces. On the other hand, for any n and D=O(n), we construct a regular triangulation of complexity Omega(nD) whose n vertices have spread D.Comment: 31 pages, 11 figures. Full version of SODA 2002 paper. Also available at http://www.cs.uiuc.edu/~jeffe/pubs/screw.htm

Review of The World Bank, A Case for Aid: Building a Consensus for Development Assistance, by James D. Wolfensohn & Nicolas Stern

[Excerpt] The World Bank’s new book, A Case for Aid: Building a Consensus for Development Assistance, indicates how dramatic and lasting the progress against global poverty has been in the past 50 years. It also shows how dramatically the Bank’s own understanding has risen, even in the past decade, of how to make its efforts more effective in relieving poverty and achieving other development goals. These two themes form the basis for the World Bank’s visionary thesis: that eradicating much of the poverty, ill health, and illiteracy around the world is within reach. The occasion for pronouncing this message in A Case for Aid was the International Conference on Financing for Development, held in Monterrey, Mexico in March 2002. The United Nations hosted this conference to chart the future of foreign aid. The conference was notable in part because of the dramatic, and surprising to some, announcement by America’s President Bush of a bold new commitment by the United States to foreign aid for the developing world. A Case for Aid memorializes this conference, and provides analysis and commentary of its issues. It includes four parts. First is a keynote speech, “A Partnership for Development and Peace,” from World Bank president James D. Wolfensohn. Second is an essay, “Making the Case for Aid,” written by World Bank chief economist Nicolas Stern after the conference. Third, forming the book’s bulk, is “The Role and Effectiveness of Development Assistance,” by a panel of World Bank authors. Finally, the book includes the official U.N. document “The Monterrey Consensus.

A Review of Selected E-Recruiting Websites: Disability Accessibility Considerations

Ten job boards1 and 31 corporate E-recruiting websites were evaluated for accessibility for people with disabilities. The examination was performed using both an automated accessibility testing software (Bobby v3.2) and an examination of a sub-sample of the sites through a “simulated” application process. The simulated application process was performed utilizing only the information available to a screen reader and navigating the site using only keyboard commands, duplicating how a blind individual would typically navigate the web. The purpose of this second method was to see if it would be possible to successfully proceed through the entire multi-step job search and application process. None of the job board pages (home, job search, signup, or resumé submittal pages) evaluated by Bobby were found to be accessible. The vast majority of corporate E-recruiting sites also failed Bobby’s tests. The simulated application process evaluation was slightly more promising, but still only three of the nine job boards and three of the twelve corporate sites evaluated were accessible enough to work through the entire process of registration, job searching, resumé submittal, and application for a position. Many of the issues encountered could easily be corrected through the consistent use of alternative text for essential submit image buttons (i.e. “apply,” “post resumé”)

Deformation invariance of rational pairs

Rational pairs, recently introduced by Koll\'ar and Kov\'acs, generalize rational singularities to pairs $(X,D)$. Here $X$ is a normal variety and $D$ is a reduced divisor on $X$. Integral to the definition of a rational pair is the notion of a thrifty resolution, also defined by Koll\'ar and Kov\'acs, and in order to work with rational pairs it is often necessary to know whether a given resolution is thrifty. In this paper we present several foundational results that are helpful for identifying thrifty resolutions and analyzing their behavior. We also show that general hyperplane sections of rational pairs are again rational. In 1978, Elkik proved that rational singularities are deformation invariant. Our main result is an analogue of this theorem for rational pairs: given a flat family $X\to S$ and a Cartier divisor $D$ on $X$, if the fibers over a smooth point $s\in S$ form a rational pair, then $(X,D)$ is also rational near the fiber $X_s$.Comment: 17 pages. Version 3: added a corollary about proper families over a curve, and a Bertini-type theorem for rational pair

Performing Empire: Theater and Colonialism in Caroline Link's Nirgendwo in Afrika

In Caroline Link's popular 2001 film Nirgendwo in Afrika, a Jewish family fleeing the Holocaust finds refuge in British-controlled Kenya. Theater plays a crucial role in the film: Members of the Redlich family explicitly call upon one another to engage in roleplaying. They make use of theater to experiment, imaginatively, with their new roles within the colonial establishment. The film's production team, as I point out, was similarly preoccupied with questions of theater and theatricality. In interviews, the film's director and producers claim that their indigenous extras struggled to understand the distinction between fiction and reality, often became overly caught up in the roles they were portraying, and could only be, not truly perform, for the camera. In this way, the film's production team discounts their indigenous extras as genuine collaborators and, ultimately, justifies their monopoly over the work of cultural representation. If theater and performance are often portrayed as opening up a path to greater political and social emancipation, we find here instead an example of how it can be used both to initiate individuals into a colonial hierarchy and to maintain and reinforce patterns of exclusion

Progress Along the Pathway for Transforming Regional Health: A Pulse Check on Multi-Sector Partnerships

Multi-sector partnerships play an increasingly significant role in the movement to improve heath, equity, and economic prosperity. These partnerships recognize that many of our most pressing challenges defy sector boundaries, and cannot be effectively addressed by any one institution alone. Progress Along the Pathway to Health System Transformation: A Pulse Check on Multi-Sector Partnerships is the only survey of its kind to ask leaders across the U.S. what their partnerships do, how they finance their work, and how their groups have been developing over time. The 2016 Pulse Check report provides a snapshot of 237 multi-sector partnerships throughout the country as well as rich detail around what contributes to—or gets in the way of—moving their important work forward. The survey revealed two sets of findings that are distinct, but closely related. These include characteristics of the partnerships and their efforts, such as composition, portfolio priorities, and financing; as well as developmental phases and the distinctive patterns of momentum builders and pitfalls that groups experience as they evolve. Further, ReThink Health has found that partnerships often face predictable challenges and can catalyze momentum in particularly powerful ways. The Pulse Check explored these barriers and drivers with a view toward understanding how partnerships may evolve along their journey. Pulse Check findings indicate that certain partnership characteristics do indeed show progressive differences across developmental phases (see graphic below). For instance, when compared to respondents in the Earlier and Middle phases, those in the Later phase tend to have partnerships that are more established, with larger staffs, a larger number active sectors, more expansive action portfolios, and longer-term financial plans

Review of The Future of Life, by Edward O. Wilson

[Excerpt] It is refreshing to read an environmental diatribe where the writer has both the authority of a world expert and a willingness to compromise to pursue realistic solutions. Wilson is a Harvard biology professor, two-time Pulitzer Prize winner, and a director of the Nature Conservancy. In The Future of Life, he presents a succinct evaluation of the great ecological issues of our day, focusing on the rapid pace of species extinctions, and on the promise of finding a balance between conservation and human activity that will bring the extinctions to a halt