Danube University Krems

About: Danube University Krems is a education organization based out in Krems, Niederösterreich, Austria. It is known for research contribution in the topics: Stroke & Population. The organization has 498 authors who have published 1572 publications receiving 68797 citations.

Impact of hard-and software timestamping on clock synchronization performance over IEEE 802.11

Abstract: The possibility of equipping devices on the factory floor with wireless communication has brought up new applications and challenges. Among one of these challenges is clock synchronization which is required for easy network management and monitoring. The IEEE 802.11v amendment to IEEE 802.11 has opened the doors for establishing clock synchronization in industrial applications by providing mechanisms and guidelines for synchronization. This work addresses the synchronization means provided by the IEEE 802.11 standard, including the ones mentioned by IEEE 802.11v, and analyses the impact of both software and hardware timestamps on the synchronization performance through test-bed implementations. The results indicate that there are several elements which can affect the quality of both software and hardware time-stamps, which in turn affect the synchronization performance. Moreover, it is also shown that the timestamping accuracy itself is only one factor, and other factors such as control loop settings and synchronization interval also affect the final synchronization performance over WLAN.

Vascularization of primary and secondary ossification centres in the human growth plate

Abstract: The switch from cartilage template to bone during endochondral ossification of the growth plate requires a dynamic and close interaction between cartilage and the developing vasculature. Vascular invasion of the primarily avascular hypertrophic chondrocyte zone brings chondroclasts, osteoblast- and endothelial precursor cells into future centres of ossification. Vascularization of human growth plates of polydactylic digits was studied by immunohistochemistry, confocal-laser-scanning-microscopy and RT-qPCR using markers specific for endothelial cells CD34 and CD31, smooth muscle cells α-SMA, endothelial progenitor cells CD133, CXCR4, VEGFR-2 and mesenchymal progenitor cells CD90 and CD105. In addition, morphometric analysis was performed to quantify RUNX2+ and DLX5+ hypertrophic chondrocytes, RANK+ chondro- and osteoclasts, and CD133+ progenitors in different zones of the growth plate. New vessels in ossification centres were formed by sprouting of CD34+ endothelial cells that did not co-express the mature endothelial cell marker CD31. These immature vessels in the growth plate showed no abluminal coverage with α-SMA+ smooth muscle cells, but in their close proximity single CD133+ precursor cells were found that did not express VEGFR-2, a marker for endothelial lineage commitment. In periosteum and in the perichondrial groove of Ranvier that harboured CD90+/CD105+ chondro-progenitors, in contrast, mature vessels were found stabilized by α-SMA+ smooth muscle cells. Vascularization of ossification centres of the growth plate was mediated by sprouting of capillaries coming from the bone collar or by intussusception rather than by de-novo vessel formation involving endothelial progenitor cells. Vascular invasion of the joint anlage was temporally delayed compared to the surrounding joint tissue.

Patients’ Perceptions of Risky Developments During Psychotherapy

Abstract: Research on risks and unwanted effects is largely missing in psychotherapy. Using exploratory factor analysis six dimensions of personal therapy situation were identified in a preliminary study, three of them were associated with risky developments during the psychotherapeutic process: (1) (poor) quality of therapeutic relationship, (2) burden caused by psychotherapy, and (3) dependency/isolation. Based on the finding of this study an online survey was performed to examine these three dimensions. Aside from these three factors another variable was associated with risky therapy developments: the online questionnaire also asked for premature terminations of psychotherapy as a consequence of risky conditions for the therapeutic development. Risky conditions were found to be associated with the following variables: (1) the combination of female patient–male therapist, (2) the therapeutic orientation (particularly with the psychodynamic approaches) and (3) the duration of therapy. Fewer humanistic and systemic psychotherapies were found among the high risk-prone group of patients who were at risk in at least three of the four variables which were associated with risky developments. Differences in the findings of the study regarding the four therapeutic orientations stress the importance of an extensive differential indication and a cooperative partnership between patient and therapist, in order to facilitate a positive patient participation towards the choice of therapy method and subsequent successful participation throughout the course of treatment. Further studies should also focus on female patient and male therapist psychotherapies.