Relativistic Jets from Active Galactic Nuclei

The nuclei of most normal galaxies contain supermassive black holes, which can accrete gas through a disk and become active. These active galactic nuclei (AGNs) can form jets that are observed on scales from astronomical units to megaparsecs and from meter wavelengths to TeV energies. High-resolution radio imaging and multiwavelength/messenger campaigns are elucidating the conditions under which this happens. Evidence is presented that: Relativistic AGN jets are formed when the black hole spins and the the accretion disk is strongly magnetized, perhaps on account of gas accreting at high latitude beyond the black hole sphere of influence. AGN jets are collimated close to the black hole by magnetic stress associated with a disk wind. Higher-power jets can emerge from their galactic nuclei in a relativistic, supersonic, and proton-dominated state, and they terminate in strong, hot spot shocks; lower-power jets are degraded to buoyant plumes and bubbles. Jets may accelerate protons to EeV energies, which contribute to the cosmic ray spectrum and may initiate pair cascades that can efficiently radiate synchrotron γ-rays. Jets were far more common when the Universe was a few billion years old and black holes and massive galaxies were growing rapidly. Jets can have a major influence on their environments, stimulating and limiting the growth of galaxies. The observational prospects for securing our understanding of AGN jets are bright

Integrating Service-Learning in the Public Speaking Course

This best-practices article endorses incorporating service-learning into the foundational public speaking course. The article explains connections between service-learning and the rhetorical tradition, highlights pedagogical approaches that would benefit from a service-learning component, and discusses the benefits of service-learning for community partners and students. The remainder of the article focuses on how to implement servicelearning in a public speaking course, including reflection and assessment recommendations

Prophylactic Insertion of Optional Vena Cava Filters in High-Risk Trauma Patients

Background:: Vena cava interruption is a form of pulmonary embolism prophylaxis that is being used in high-risk patients who do not tolerate pharmacologic prophylaxis. Retrievable prophylactic vena cava filters (VCFs) are of particular interest for severely injured patients where the necessity for VCF is often only temporary. Methods:: In a single-institution case series of consecutive patients who received prophylactic VCFs after polytrauma, between 04/1998 and 07/2004, the demographic data, injury pattern and complications were analysed. Results:: Ninety-five prophylactic VCFs were placed in polytrauma patients (median ISS of 38). Median age was 38 years (range 16-80 years). Median delay between trauma and filter placement was 1 day (range 0-31 days). No complication was seen related to filter insertion or retrieval. Sixty-five VCFs (68.4%) were retrieved after 4-25 days (median 13 days). One filter migration (1.1%) was observed. Retrieval failed in two patients (3.0%). A total of 30 VCFs (31.6%) were left permanently. One non-fatal PE (1.1%) occurred 21 days after filter retrieval despite prophylaxis with LMWH. DVT developed in two patients (2.1%) including one vena caval occlusion (1.1%). Overall mortality was 7.4%. Conclusions:: Early prophylactic placement of VCF in a high-risk trauma patient should be considered when anticoagulation is contraindicated. Filter insertion and retrieval is safe with a low complication rat

Primary Hemiarthroplasty for Proximal Humeral Fractures in the Elderly: Long-Term Functional Outcome and Social Implications

Background:: Primary shoulder hemiarthroplasty is an established treatment modality for complex fractures of the proximal humerus. Long-term functional outcome is often disappointing. However, little is known about social implications particularly in the elderly. Methods:: A single-institution case series of consecutive geriatric patients (age > 70 years) treated with shoulder hemiarthroplasty for complex fractures of the proximal humerus between 1994 and 1997 was analysed. Postoperative morbidity, long-term function, radiological outcome and social implications were evaluated. Results:: Seventy-seven patients fulfilled the study criteria. Median age at the time of operation was 80 years (range 70-93 years). Systemic and local postoperative complications were observed in 8% including 2 patients (3%) with revision surgery. Postoperative mortality was 1%. Forty-eight patients (62%) were available for follow-up (median 49 months, range 25-80 months), 22 (29%) died from causes unrelated to hemiarthroplasty before follow-up and 7 patients (9%) did not attend follow-up examination. Median Constant-Murley score was 41 points (range 17-77 points). Long-term results concerning pain were satisfying. The Oxford shoulder score ranged from 14 to 40 (median 30). Forty-one patients (85%) still lived in their original environment and managed their daily life independently despite poor shoulder function. Four patients (8%) lived in a retirement home and 3 (6%) in a nursery home. Eighty percent of our patients were still able to use public transportation, do the daily shopping and wash their whole body by themselves. Conclusion:: Most patients managed their daily life independently despite poor shoulder functio

Relativistic Jets from Active Galactic Nuclei

The nuclei of most normal galaxies contain supermassive black holes, which can accrete gas through a disk and become active. These active galactic nuclei (AGNs) can form jets that are observed on scales from astronomical units to megaparsecs and from meter wavelengths to TeV energies. High-resolution radio imaging and multiwavelength/messenger campaigns are elucidating the conditions under which this happens. Evidence is presented that: Relativistic AGN jets are formed when the black hole spins and the the accretion disk is strongly magnetized, perhaps on account of gas accreting at high latitude beyond the black hole sphere of influence. AGN jets are collimated close to the black hole by magnetic stress associated with a disk wind. Higher-power jets can emerge from their galactic nuclei in a relativistic, supersonic, and proton-dominated state, and they terminate in strong, hot spot shocks; lower-power jets are degraded to buoyant plumes and bubbles. Jets may accelerate protons to EeV energies, which contribute to the cosmic ray spectrum and may initiate pair cascades that can efficiently radiate synchrotron γ-rays. Jets were far more common when the Universe was a few billion years old and black holes and massive galaxies were growing rapidly. Jets can have a major influence on their environments, stimulating and limiting the growth of galaxies. The observational prospects for securing our understanding of AGN jets are bright

TinyNode: A Comprehensive Platform for Wireless Sensor Network Applications

We introduce the TinyNode platform for wireless sensor networks. Supporting both research and industrial deployments, the platform offers communication ranges that exceed current platforms by a factor of 3 to 5, while consuming similar energy. It comes with a rich, practical set of hardware extensions and full TinyOS support. We describe the design choices of the TinyNode, the accompanying hardware modules, and the MAC layer implementation

Taking Sides with Pain – Lateralization aspects Related to Cerebral Processing of Dental Pain

The current fMRI study investigated cortical processing of electrically induced painful tooth stimulation of both maxillary canines and central incisors in 21 healthy, right-handed volunteers. A constant current, 150% above tooth specific pain perception thresholds was applied and corresponding online ratings of perceived pain intensity were recorded with a computerized visual analog scale during fMRI measurements. Lateralization of cortical activations was investigated by a region of interest analysis. A wide cortical network distributed over several areas, typically described as the pain or nociceptive matrix, was activated on a conservative significance level. Distinct lateralization patterns of analyzed structures allow functional classification of the dental pain processing system. Namely, certain parts are activated independent of the stimulation site, and hence are interpreted to reflect cognitive emotional aspects. Other parts represent somatotopic processing and therefore reflect discriminative perceptive analysis. Of particular interest is the observed amygdala activity depending on the stimulated tooth that might indicate a role in somatotopic encoding