Reversal of the extraordinary Hall effect polarity in thin Co/Pd multilayers

Thin Co/Pd multilayers, with room temperature perpendicular anisotropy and an enhanced surface scattering, were studied for the possible use in the extraordinary Hall effect (EHE) - based magnetic memory devices. Polarity of the EHE signal was found to change from negative in thick samples to positive in thin ones. Reversal of EHE sign was also observed in thick samples with aging. The effect is argued to be related to the dominance of surface scattering having the EHE polarity opposite to that of the bulk

Inhomogeneity and transverse voltage in superconductors

Voltages parallel and transverse to electric current in slightly inhomogeneous superconductors can contain components proportional to the field and temperature derivatives of the longitudinal and Hall resistivities. We show that these anomalous contributions can be the origin of the zero field and even-in-field transverse voltage occasionally observed at the superconductor to normal state transition. The same mechanism can also cause an anomaly in the odd-in-field transverse voltage interfering the Hall effect signal.Comment: 6 pages, 7 figure

Electromagnetically Induced Transparency from a Single Atom in Free Space

We report an absorption spectroscopy experiment and the observation of electromagnetically induced transparency from a single trapped atom. We focus a weak and narrowband Gaussian light beam onto an optically cooled Barium ion using a high numerical aperture lens. Extinction of this beam is observed with measured values of up to 1.3 %. We demonstrate electromagnetically induced transparency of the ion by tuning a strong control beam over a two-photon resonance in a three-level lambda-type system. The probe beam extinction is inhibited by more than 75 % due to population trapping.Comment: 4 pages, 3 figure

Anästhesieeinleitung und Intubation beim Kind mit vollem Magen: Zeit zum Umdenken!

Zusammenfassung: Die klassische in der Erwachsenenanästhesie übliche Vorgehensweise bei der Ileusintubation ist für die Anwendung bei Kindern nicht in allen Punkten zweckmäßig. Erschwerte Präoxygenation, verminderte Sauerstoffreserven, erhöhter Sauerstoffverbrauch sowie Atelektasenneigung führen beim Neugeborenen, Säugling und Kleinkind zu einer verkürzten Apnoetoleranz mit sehr schnell eintretender Hypoxämie nach der Anästhesieeinleitung. Eine sanfte Maskenbeatmung mit Drucklimitierung bei 10-12cmH2O führt nicht zur Mageninflation mit Aspiration. Hauptfaktoren für eine Aspiration bei Kindern sind Sperren, Pressen, Husten des Patienten während der Anästhesieeinleitung und Intubationsversuchen bei inadäquater Muskelrelaxation. Die sanfte Maskenbeatmung erlaubt eine ruhige, kontrollierte endotracheale Intubation bei optimierter Oxygenation, hämodynamischer Stabilität, genügender Anästhesietiefe und vollständiger Muskelrelaxation. Die Anwendung des Krikoiddrucks hat sich in der Praxis zur Verhinderung einer Aspiration nicht immer als effektiv erwiesen. Unmittelbar nach der Einleitung durchgeführt, kann er zu Husten und Pressen sowie zu erschwerter Beatmung und Intubation führen; er ist damit kontraproduktiv und provoziert geradezu eine Aspiration. Deshalb soll der Krikoiddruck bei der "Rapid-sequence-induction"- (RSI-)Intubation beim Kind in der Regel nicht angewendet werden. Wichtige Elemente einer an die Kinderanästhesie adaptierten RSI-Intubation sind die suffiziente schnelle i.v.-Anästhesieeinleitung mit profunder Muskelrelaxation, die sanfte Maskenbeatmung mit Druckbegrenzung bei 10-12cmH2O und die atraumatische Intubation unter kontrollierten Bedingunge

VoIP: a Corporate Governance Approach to Avoid the Risk of Civil Liability

Since the deregulation of Voice over Internet Protocol (VoIP) in 2005, many South African organizations are now attempting to leverage its cost saving and competitive values. However it has been recently cited that VoIP is one of the greatest new risks to business. This risk is cited to increase Information Security insurance premiums in the near future. Due to the dynamic nature of the technology, regulatory and legislative concerns such as lawful interception of communications and privacy may also contribute to business risk. VoIP consists of both direct communications (voice conversation) and indirect communications (voice mails, emails and instant messaging). Due to this dual nature, complying with regulations such as the Regulation of Interception of Communications and Provision of Communication-Related Information Act (RICA) should be considered. In order to leverage value from the VoIP implementation, an executive or SME owner should look to implement the technology with knowledge of the potential risk of civil liability. This is further highlighted by the King III Report which makes the Directors and CEO of an organisation ultimately responsible for IT Governance and Information Security Governance. The report goes further to say, any new technology, such as VoIP, should comply with all South African legislation and regulations. This responsibility encourages the practice of both due care and due diligence. However, recent trends exercised by Information Security professionals, responsible for drafting Information Security policies, often neglect the regulatory requirements and choose to only implement International best practices with no considerations to the risk of civil liability. Although these best practice frameworks may inadvertently comply with existing local legislation, a chance of an oversight is a possibility. Oversights may not only result in criminal sanctions but also civil action due to losses or damages suffered by a third party. Using both the identified regulations and relevant International best practices one may attempt to ensure good Governance with regards to VoIP’s dual nature. The aim is to aid executives and SME owners in mitigating the risk of civil liability to better leverage VoIP’s value by utilizing the proposed VoIP: Civil Liability Risk Table. This should aid in the exercise of due care and due diligence when implementing VoIP as a means of conducting business communication

Investigation of dual polarization laser modulation

Dual polarization lasers for wideband optical communication