This paper contributes to the broad literature on public services contracting in two ways. First, we provide an empirical analysis of contracting decisions in the provision of welfare-to-work (WTW) services. We estimate both the WTW-contracting decisions of Dutch municipalities and their impact on the performance, measured as the fraction of Social Assistance (SA) recipients. Second, we explici...

The textit{QIF}  (Quadrant Interlocking Factorization) method of Evans and Hatzopoulos solves linear equation systems using textit{WZ}  factorization. The  WZ factorization can be faster than the textit{LU} factorization  because,  it performs the simultaneous evaluation of two columns or two rows. Here, we present a  method for computing the real and integer textit{WZ} and  textit{ZW} factoriz...

Since 2007, several contributions have tried to identify early-warning signals of the financial crisis. However, the vast majority of analyses has focused on financial systems and little theoretical work has been done on the economic counterpart. In the present paper we fill this gap and employ the theoretical tools of network theory to shed light on the response of world trade to the financial...

Recent reports show growing reserves of unconventional gas are available and that there is an appetite from policy makers, industry, and others to better understand the GHG impact of exploiting reserves such as shale gas. There is little publicly available data comparing unconventional and conventional gas production. Existing studies rely on national inventories, but it is not generally possib...

BACKGROUND Cataract surgery is the most common surgical procedure in ophthalmology. Biometry data and accurate intraocular lens (IOL) calculations are very important in achieving the desired refractive outcomes. The aim of this study was to compare measurements using a new optical low coherence reflectometry (OLCR) biometer (OA-2000) and the gold standard partial coherence interferometry (PCI) ...

PURPOSE To compare the repeatability and reproducibility of ocular biometry and intraocular lens (IOL) power obtained with a new optical biometer (AL-Scan) and a standard optical biometer (IOLMaster 500). SETTING Siriraj Hospital, Mahidol University, Bangkok, Thailand. DESIGN Prospective comparative study. METHODS Two independent operators measured eyes with cataract using both biometers....

In this article the notions of semi weak orthogonality and semi weak factorization structure in a category $mathcal X$ are introduced. Then the relationship between semi weak factorization structures and quasi right (left) and weak factorization structures is given. The main result is a characterization of semi weak orthogonality, factorization of morphisms, and semi weak factorization structur...

Trade is a fundamental pillar of economy and a form of social organization. Its empirical characterization at the worldwide scale is represented by the World Trade Web (WTW), the network built upon the trade relationships between the different countries. Several scientific studies have focused on the structural characterization of this network, as well as its dynamical properties, since we have...

A fuel-cycle model—called the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model—has been developed at Argonne National Laboratory to evaluate well-to-wheels (WTW) energy and emission impacts of motor vehicle technologies fueled with various transportation fuels. The new GREET version has up-to-date information regarding energy use and emissions for fuel produ...

An outbreak in the autumn of 2005 resulted in 218 confirmed cases of Cryptosporidium hominis. The attack rate (relative risk 4.1, 95%CI 2.8-9.1) was significantly higher in the population supplied by Cwellyn Water Treatment Works (WTW). A case-control study demonstrated a statistically significant association (odds ratio 6.1, 95% CI 1.8-23.8) between drinking unboiled tap water and C. hominis i...