OBJECTIVE This study examined the prospective relationship of substance use and mental health problems with risk of discontinuous enrollment in college. METHODS Participants were 1,145 students at a large public university who were interviewed annually for four years beginning at college entry in 2004 (year 1). Discontinuous enrollment was defined as a gap in enrollment of one or more semeste...

The seeking of discontinuity in enumeration was recently renewed because Cowan [Cowan, N. (2001). The magical number 4 in short-term memory: A reconsideration of mental storage capacity. Behavioral and Brain Sciences, 24, 87-185; Cowan, N. (2005). Working memory capacity. Hove: Psychology Press] suggested that it allows evaluating the limit of the focus of attention, currently estimated at four...

Recent empirical work in several economic fields, particularly environmental and energy economics, has adapted the regression discontinuity framework to applications where time is the running variable and treatment occurs at the moment of the discontinuity. In this guide for practitioners, we discuss several features of this “Regression Discontinuity in Time” framework that differ from the more...

A method for the simulation of discontinuities in photonic crystal defect waveguides is presented. This frequency domain technique is based on the multiple multipole method. In contrast with other known techniques, spurious reflections (due to the impedance mismatch at the waveguide terminations) are avoided. The absence of spurious reflections allows one to characterize precisely the intrinsic...

The regression discontinuity model has recently become a commonly applied framework for empirical work in economics. Hahn, Todd, and Van der Klaauw (2001) provide a formal development of the identification of a treatment effect in this framework and also note the potential bias problems in its estimation. This bias difficulty is the result of a particular feature of the regression discontinuity...

The search for a full treatment of wrapping in type logical grammar has been a task of long-standing. In this paper we present a calculus for discontinuity addressing this challenge, ω-DL. The calculus allows an unbounded number of points of discontinuity (hence the prefix ω-) and includes both deterministic and nondeterministic discontinuous connectives. We believe that it constitutes a genera...

We report on a study of the carrier-phase time transfer boundary discontinuity by the use of the precise point positioning (PPP) technique. Carrier-phase time transfer is first compared with two-way satellite time and frequency transfer (TWSTFT) between the same stations. It matches TWSTFT quite well and provides better short-term stability. Later, we extract 1-day data-arc boundary discontinui...

Regression discontinuity analyses can generate estimates of the causal effects of an exposure when a continuously measured variable is used to assign the exposure to individuals based on a threshold rule. Individuals just above the threshold are expected to be similar in their distribution of measured and unmeasured baseline covariates to individuals just below the threshold, resulting in excha...

Block volumes are generally estimated by analyzing the discontinuity spacing measurements obtained either from the scan lines placed over the rock exposures or the borehole cores. Discontinuity spacing measurements made at the Mesozoic limestone quarries in Karaburun Peninsula were used to estimate the average block volumes that could be produced from them using the suggested methods in the lit...

We investigate a modiication of Horn and Schunck's approach which leads to a better preservation of ow discontinuities. It replaces the quadratic smoothness term by a nonquadratic one. Energy minimization by steepest descent leads to a system of two nonlinear diiusion{reaction equations with a single common nonlinear diiusivity. This enables us to make use from techniques for nonlinear diiusion...