Drift estimation in sparse sequential dynamic imaging, with application to nanoscale fluorescence microscopy.

A major challenge in many modern superresolution fluorescence microscopy techniques at the nanoscale lies in the correct alignment of long sequences of sparse but spatially and temporally highly resolved images. This is caused by the temporal drift of the protein structure, e.g. due to temporal thermal inhomogeneity of the object of interest or its supporting area during the observation process. We develop a simple semiparametric model for drift correction in single-marker switching microscopy. Then we propose an M-estimator for the drift and show its asymptotic normality. This is used to correct the final image and it is shown that this purely statistical method is competitive with state of the art calibration techniques which require the incorporation of fiducial markers in the specimen. Moreover, a simple bootstrap algorithm allows us to quantify the precision of the drift estimate and its effect on the final image estimation. We argue that purely statistical drift correction is even more robust than fiducial tracking, rendering the latter superfluous in many applications. The practicability of our method is demonstrated by a simulation study and by a single-marker switching application. This serves as a prototype for many other typical imaging techniques where sparse observations with high temporal resolution are blurred by motion of the object to be reconstructed

Determinants of self-reporting under the European corporate leniency program

We empirically investigate the determinants of self-reporting under the European corporate leniency program. Applying a data set consisting of 442 firm groups that participated in 76 cartels decided by the European Commission between 2000 and 2011, we find that the probability of a firm becoming the chief witness increases with its character as repeat offender, the size of the expected basic fine, the number of countries active in one group as well as the size of the firm’s share in the cartelized market. Our results have important implications for an effective prosecution of anti-cartel law infringers

Empirical investigation of perspective-based reading: A replicated experiment

Inspection is considered a powerful method to detect defects in a software artifact. It is reported that savings are particularly high if inspections are used in early phases of the software development process, i.e. in the requirements definition phase. However, only few systematic techniques exist to support defect detection in requirements documents. One is perspective-based reading (PBR). The effectiveness of this technique has been validated in an experiment with software professionals at NASA/Goddard Space Flight Center. In this paper we describe a replication of this experiment within an academic environment to validate the original results. In the original experiment, no real team meetings were performed, i.e. the individual results were pooled into nominal team results. In contrast, in our replication effort we performed real team meetings, which allowed us to make a comparison between real and nominal teams. Moreover, we investigated how the technique supports detection of de fects belonging to different defect classes. The results are three-fold: (1) We basically confirm the results of the original experiment, that PBR helps to increase individual and team defect detection effectiveness compared to an Ad-hoc approach. (2) We found no statistically significant difference between real and nominal teams. (3) The analysis according to different defect classes only yield few statistically significant results due to the experimental setting. To document data collection and analysis, we used the Goal/Question/Metric approach. We found it highly beneficial for structuring data collection and analysis especially for replication purposes

On Uniqueness of Equilibria in the CAPM

"- This paper replaces the paper ""Existence and Uniqueness of Equilibria in the CAPM"" -nIn the standard CAPM with a riskless asset we give a sufficient condition for uniqueness. This condition is a joint restriction on the agents' endowments and their preferences which is compatible with non-increasing absolute risk aversion and which is in particular satisfied with constant absolute risk aversion. Moreover in the CAPM without a riskless asset we give an example for multiple equilibria even though all agents have constant absolute risk aversion.