Outbreak by serratia marcescens producing carbapenemases in an adult intensive care unit

Serratia marcescens (SM) es un bacilo Gram-negativo perteneciente a la familia Enterobacteriaceae, reconocido como patógeno oportunista asociado a brotes nosocomiales. Es naturalmente resistente a tetraciclina, amoxicilina, amoxicilina-clavulánico, cefalotina y colistin. En los últimos años existe preocupación por la gran dispersión de los bacilos gramnegativos resistentes a los carbapenémicos (KPC), también causantes de brotes nosocomiales; éstas aumentan la morbimortalidad, los costos hospitalarios y prolon-gan la internación. En nuestro hospital en la Unidad de Cuidados Intensivos (UCI) en el año 2012 tuvimos el primer caso de Infección por SM KPC, constituyéndose un gran desafío médico y de control de infecciones en cuanto al tratamiento, y medidas de control

Anthropogenic-scale CO2 degassing from the Central Atlantic Magmatic Province as a driver of the end-Triassic mass extinction

The climatic and environmental impact of exclusively volcanic CO2 emissions is assessed during the main effusive phase of the Central Atlantic Magmatic Province (CAMP), which is synchronous with the end-Triassic mass extinction. CAMP volcanism occurred in brief and intense eruptive pulses each producing extensive basaltic lava flows. Here, CAMP volcanic CO2 injections into the surface system are modelled using a biogeochemical box model for the carbon cycle. Our modelling shows that, even if positive feedback phenomena may be invoked to explain the carbon isotope excursions preserved in end-Triassic sedimentary records, intense and pulsed volcanic activity alone may have caused repeated temperature increases and pH drops, up to 5 °C and about 0.2 log units respectively. Hence, rapid and massive volcanic CO2 emissions from CAMP, on a similar scale to current anthropogenic emissions, severely impacted on climate and environment at a global scale, leading to catastrophic biotic consequences

Deep CO₂ in the end-Triassic Central Atlantic Magmatic Province

Large Igneous Province eruptions coincide with many major Phanerozoic mass extinctions, suggesting a cause-effect relationship where volcanic degassing triggers global climatic changes. In order to fully understand this relationship, it is necessary to constrain the quantity and type of degassed magmatic volatiles, and to determine the depth of their source and the timing of eruption. Here we present direct evidence of abundant CO2 in basaltic rocks from the end-Triassic Central Atlantic Magmatic Province (CAMP), through investigation of gas exsolution bubbles preserved by melt inclusions. Our results indicate abundance of CO2 and a mantle and/or lower-middle crustal origin for at least part of the degassed carbon. The presence of deep carbon is a key control on the emplacement mode of CAMP magmas, favouring rapid eruption pulses (a few centuries each). Our estimates suggest that the amount of CO2 that each CAMP magmatic pulse injected into the end-Triassic atmosphere is comparable to the amount of anthropogenic emissions projected for the 21st century. Such large volumes of volcanic CO2 likely contributed to end-Triassic global warming and ocean acidification

Massive methane fluxing from magma–sediment interaction in the end-Triassic Central Atlantic Magmatic Province

Exceptional magmatic events coincided with the largest mass extinctions throughout Earth’s history. Extensive degassing from organic-rich sediments intruded by magmas is a possible driver of the catastrophic environmental changes, which triggered the biotic crises. One of Earth’s largest magmatic events is represented by the Central Atlantic Magmatic Province, which was synchronous with the end-Triassic mass extinction. Here, we show direct evidence for the presence in basaltic magmas of methane, generated or remobilized from the host sedimentary sequence during the emplacement of this Large Igneous Province. Abundant methane-rich fluid inclusions were entrapped within quartz at the end of magmatic crystallization in voluminous (about 1.0 × 106 km3) intrusions in Brazilian Amazonia, indicating a massive (about 7.2 × 103 Gt) fluxing of methane. These micrometre-sized imperfections in quartz crystals attest an extensive release of methane from magma–sediment interaction, which likely contributed to the global climate changes responsible for the end-Triassic mass extinction

Some remarks about underused Loedel diagrams

We emphasize that it can be didactically very useful for students to realize how a space-time diagram of an observer, moving with a constant velocity with respect to another observer, can be obtained easily by means of a standard matrix of rotation, without recourse to imaginary axes and angles. These diagrams were introduced for the first time by Loedel and their main advantage over Minkowski diagrams is that a scale factor is not necessary to convert the units of an observer to those of another observer. We show this well-known property of Loedel diagrams using a new geometric approach. © 2013 IOP Publishing Ltd

A little help for a better understanding and application of Faraday's law

In this letter, we examine Faraday's law of induction, analysing the electromotive force generated by a Lorentz force and the one generated by an electric field due to a changing magnetic field. We obtain the result in a didactically simple and appealing way. The final formula is derived considering explicitly the dependence of the magnetic field on the space coordinates, which is often neglected in standard textbooks