Cardiac arrest in a teenager - a case report

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenCardiac arrest is rarely seen in children and teenagers. We present a 12-year old girl with cardiac arrest following myocardial infarction, that required prolonged cardiac massage and extracorporeal-membranous-oxygenation (ECMO). At coronary angiography the left main coronary artery (LMCA) was stented for a suspected coronary dissection. The contraction of the heart improved and the ECMO-treatment was discontinued a week later. The patient was discharged home, but six months later a coronary artery bypass surgery was performed for in-stent restenosis. Further work-up with computed tomography (CT) showed that the LMCA originated from the right aortic sinus instead of the the left one. This case demonstrates how life threatening myocardial infarction can be caused by coronary artery anomalies.Hjartastopp er sjaldgæft hjá börnum og unglingum. Lýst er 12 ára stúlku sem fór í hjartastopp eftir brátt hjartadrep þar sem beita varð langvarandi hjartahnoði og hjarta- og lungnavél til að bjarga lífi hennar. Við kransæðaþræðingu vaknaði grunur um flysjun í vinstri kransæðarstofni og var því komið fyrir kransæðastoðneti. Samdráttur hjartans lagaðist og var hjarta- og lungnavélin aftengd viku síðar. Hún útskrifaðist heim en hálfu ári síðar sást endurþrenging í stoðnetinu og var því gerð kransæðahjáveituaðgerð. Á tölvusneiðmyndum sást að um meðfæddan galla var að ræða þar sem vinstri kransæðarstofn átti upptök frá hægri ósæðarbolla í stað þess vinstra. Tilfellið sýnir að kransæðamissmíð getur valdið lífshættulegu hjartadrepi

Aircraft-based observations and high-resolution simulations of an Icelandic dust storm

The first aircraft-based observations of an Icelandic dust storm are presented. The measurements were carried out over the ocean near Iceland's south coast in February 2007. This dust event occurred in conjunction with an easterly barrier jet of more than 30 m s<sup>−1</sup>. The aircraft measurements show high particle mass mixing ratios in an area of low wind speeds in the wake of Iceland near the coast, decreasing abruptly towards the jet. Simulations from the Weather Research and Forecasting Model coupled with Chemistry (WRF/Chem) indicate that the measured high mass mixing ratios and observed low visibility inside the wake are due to dust transported from Icelandic sand fields towards the ocean. This is confirmed by meteorological station data. Glacial outwash terrains located near the Mýrdalsjökull glacier are among simulated dust sources. Sea salt aerosols produced by the impact of strong winds on the ocean surface started to dominate as the aircraft flew away from Iceland into the jet. The present results support recent studies which suggest that Icelandic deserts should be considered as important dust sources in global and regional climate models

Simple Space-Time Symmetries: Generalizing Conformal Field Theory

We study simple space-time symmetry groups G which act on a space-time manifold M=G/H which admits a G-invariant global causal structure. We classify pairs (G,M) which share the following additional properties of conformal field theory: 1) The stability subgroup H of a point in M is the identity component of a parabolic subgroup of G, implying factorization H=MAN, where M generalizes Lorentz transformations, A dilatations, and N special conformal transformations. 2) special conformal transformations in N act trivially on tangent vectors to the space-time manifold M. The allowed simple Lie groups G are the universal coverings of SU(m,m), SO(2,D), Sp(l,R), SO*(4n) and E_7(-25) and H are particular maximal parabolic subgroups. They coincide with the groups of fractional linear transformations of Euklidean Jordan algebras whose use as generalizations of Minkowski space time was advocated by Gunaydin. All these groups G admit positive energy representations. It will also be shown that the classical conformal groups SO(2,D) are the only allowed groups which possess a time reflection automorphism; in all other cases space-time has an intrinsic chiral structure.Comment: 37 pages, 4 Table

Transactional Support for Visual Instance Search

International audienceThis article addresses the issue of dynamicity and durability for scalable indexing of very large and rapidly growing collections of local features for visual instance retrieval. By extending the NV-tree, a scalable disk-based high-dimensional index, we show how to implement the ACID properties of transactions which ensure both dynamicity and durability. We present a detailed performance evaluation of the transactional NV-tree, showing that the insertion throughput is excellent despite the effort to enforce the ACID properties

Synthesis of accelerograms compatible with the Chinese GB 50011-2001 design spectrum via harmonic wavelets: artificial and historic records

A versatile approach is employed to generate artificial accelerograms which satisfy the compatibility criteria prescribed by the Chinese aseismic code provisions GB 50011-2001. In particular, a frequency dependent peak factor derived by means of appropriate Monte Carlo analyses is introduced to relate the GB 50011-2001 design spectrum to a parametrically defined evolutionary power spectrum (EPS). Special attention is given to the definition of the frequency content of the EPS in order to accommodate the mathematical form of the aforementioned design spectrum. Further, a one-to-one relationship is established between the parameter controlling the time-varying intensity of the EPS and the effective strong ground motion duration. Subsequently, an efficient auto-regressive moving-average (ARMA) filtering technique is utilized to generate ensembles of non-stationary artificial accelerograms whose average response spectrum is in a close agreement with the considered design spectrum. Furthermore, a harmonic wavelet based iterative scheme is adopted to modify these artificial signals so that a close matching of the signals’ response spectra with the GB 50011-2001 design spectrum is achieved on an individual basis. This is also done for field recorded accelerograms pertaining to the May, 2008 Wenchuan seismic event. In the process, zero-phase high-pass filtering is performed to accomplish proper baseline correction of the acquired spectrum compatible artificial and field accelerograms. Numerical results are given in a tabulated format to expedite their use in practice