Diamond thin Film Detectors for Beam Monitoring Devices

Diamonds offer radiation hard sensors, which can be used directly in primary beams. Here we report on the use of a polycrystalline CVD diamond strip sensor as beam monitor of heavy ion beams with up to 2.10^9 lead ions per bunch. The strips allow for a determination of the transverse beam profile to a fraction of the pitch of the strips, while the timing information yields the longitudinal bunch length with a resolution of the order of a few mm.Comment: 6 pages, 7 figures, to appear in the Proceedings of the Hasselt Diamond Workshop (Hasselt, Belgium, Feb. 2006), v4: accidentally submitted figure, appearing at end, remove

How does the substrate affect the Raman and excited state spectra of a carbon nanotube?

We study the optical properties of a single, semiconducting single-walled carbon nanotube (CNT) that is partially suspended across a trench and partially supported by a SiO2-substrate. By tuning the laser excitation energy across the E33 excitonic resonance of the suspended CNT segment, the scattering intensities of the principal Raman transitions, the radial breathing mode (RBM), the G-mode and the D-mode show strong resonance enhancement of up to three orders of magnitude. In the supported part of the CNT, despite a loss of Raman scattering intensity of up to two orders of magnitude, we recover the E33 excitonic resonance suffering a substrate-induced red shift of 50 meV. The peak intensity ratio between G-band and D-band is highly sensitive to the presence of the substrate and varies by one order of magnitude, demonstrating the much higher defect density in the supported CNT segments. By comparing the E33 resonance spectra measured by Raman excitation spectroscopy and photoluminescence (PL) excitation spectroscopy in the suspended CNT segment, we observe that the peak energy in the PL excitation spectrum is red-shifted by 40 meV. This shift is associated with the energy difference between the localized exciton dominating the PL excitation spectrum and the free exciton giving rise to the Raman excitation spectrum. High-resolution Raman spectra reveal substrate-induced symmetry breaking, as evidenced by the appearance of additional peaks in the strongly broadened Raman G band. Laser-induced line shifts of RBM and G band measured on the suspended CNT segment are both linear as a function of the laser excitation power. Stokes/anti-Stokes measurements, however, reveal an increase of the G phonon population while the RBM phonon population is rather independent of the laser excitation power.Comment: Revised manuscript, 20 pages, 8 figure

Tackling the Algorithmic Control Crisis -the Technical, Legal, and Ethical Challenges of Research into Algorithmic Agents

Algorithmic agents permeate every instant of our online existence. Based on our digital profiles built from the massive surveillance of our digital existence, algorithmic agents rank search results, filter our emails, hide and show news items on social networks feeds, try to guess what products we might buy next for ourselves and for others, what movies we want to watch, and when we might be pregnant. Algorithmic agents select, filter, and recommend products, information, and people; they increasingly customize our physical environments, including the temperature and the mood

Induction of osteoclast characteristics in cultured avian blood monocytes; modulation by osteoblasts and 1,25-(OH)2 vitamin D3

It has been established, that the osteoclast is derived from the haemopoietic stem cell, but its exact lineage is still controversial. It is sometimes suggested, that osteoclasts and monocytes/macrophages are related cells. It has also been suggested that osteoclast differentiation is regulated by osteoblasts and 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3). In the present paper we addressed the question whether avian monocytes can differentiate into osteoclasts in vitro, using an array of immunocytochemical, enzyme cytochemical and function markers. We have also determined the effects of osteoblasts, osteoblast conditioned medium and 1,25-(OH)2D3 on the expression of osteoclastic features on monocytes during culture. Monocytes developed tartrate resistant acid phosphatase (TRAcP) enzyme activity and antigens for all anti-osteoclast antibodies tested, during culture. However, they did not acquire the ability to resorb dentine and still showed phagocytosis of latex spheres. This indicates that the monocytes developed into cells resembling osteoclasts but lacking their function while retaining the function of macrophages. Osteoblast conditioned medium stimulated TRAcP enzyme activity and proliferation of monocytes in cultures. Addition of osteoblasts or osteoblast conditioned medium to monocyte cultures on dentine in the presence or absence of 1,25-(OH)2D3 did not result in the generation of genuine osteoclasts, nor in pit formation. 1,25-(OH)2D3 appeared to be cytotoxic to the avian monocytes in concentrations considered optimal for mouse osteoclast formation. These results suggest that avian monocytes do not readily differentiate into osteoclasts under in vitro conditions that stimulate osteoclast differentiation from bone marrow derived haemopoietic cells. Furthermore, labelling with anti-osteoclast antibodies and TRAcP as osteoclast-markers should be used only with great caution in the identification of osteoclasts formed in vitro

The relative importance of comprehensive performance measurement systems and financial performance measures on employees’ perceptions of informational fairness

Research on how performance measurement systems affect employees' perceptions of workplace fairness is important. As organizations often rely on their performance measurement systems to communicate information to their employees, it is useful to ascertain if and how the developments of performance measurement systems that are far more comprehensive than traditional financial systems affect employees' perceptions of informational fairness through the information communicated to employees. Informational fairness refers to employees' perceptions of workplace fairness that is based on the amount and the truthfulness of information that organizations provide to their employees. Based on a sample of managers from manufacturing organizations, the Partial Least Square results indicate that comprehensive performance measurement systems (comprehensive PMS) have a significant direct effect on jobrelevant information. They also indicate that comprehensive PMS have an indirect effect on informational fairness via job-relevant information. In contrast, systems that are based on financial measures have no significant effects on job-relevant information and informational fairness. These results demonstrate how comprehensive PMS (through the communication of a greater amount of job-relevant information) can be used to engender employees' perceptions of high workplace fairnes