A novel satellite mission concept for upper air water vapour, aerosol and cloud observations using integrated path differential absorption LiDAR limb sounding

We propose a new satellite mission to deliver high quality measurements of upper air water vapour. The concept centres around a LiDAR in limb sounding by occultation geometry, designed to operate as a very long path system for differential absorption measurements. We present a preliminary performance analysis with a system sized to send 75 mJ pulses at 25 Hz at four wavelengths close to 935 nm, to up to 5 microsatellites in a counter-rotating orbit, carrying retroreflectors characterized by a reflected beam divergence of roughly twice the emitted laser beam divergence of 15 µrad. This provides water vapour profiles with a vertical sampling of 110 m; preliminary calculations suggest that the system could detect concentrations of less than 5 ppm. A secondary payload of a fairly conventional medium resolution multispectral radiometer allows wide-swath cloud and aerosol imaging. The total weight and power of the system are estimated at 3 tons and 2,700 W respectively. This novel concept presents significant challenges, including the performance of the lasers in space, the tracking between the main spacecraft and the retroreflectors, the refractive effects of turbulence, and the design of the telescopes to achieve a high signal-to-noise ratio for the high precision measurements. The mission concept was conceived at the Alpbach Summer School 2010

Enterococcal colonization of infants in a neonatal intensive care unit: associated predictors, risk factors and seasonal patterns

<p>Abstract</p> <p>Background</p> <p>During and shortly after birth, newborn infants are colonized with enterococci. This study analyzes predictors for early enterococcal colonization of infants in a neonatal intensive care unit and describes risk factors associated with multidrugresistant enterococci colonization and its seasonal patterns.</p> <p>Methods</p> <p>Over a 12-month period, we performed a prospective epidemiological study in 274 infants admitted to a neonatal intensive care unit. On the first day of life, we compared infants with enterococcal isolates detected in meconium or body cultures to those without. We then tested the association of enterococcal colonization with peripartal predictors/risk factors by using bivariate and multivariate statistical methods.</p> <p>Results</p> <p>Twenty-three percent of the infants were colonized with enterococci. The three most common enterococcal species were <it>E. faecium </it>(48% of isolates), <it>E. casseliflavus </it>(25%) and <it>E. faecalis </it>(13%). Fifty-seven percent of the enterococci found were resistant to three of five antibiotic classes, but no vancomycin-resistant isolates were observed. During winter/spring months, the number of enterococci and multidrug-resistant enterococci were higher than in summer/fall months (p = 0.002 and p < 0.0001, respectively). With respect to enterococcal colonization on the first day of life, predictors were prematurity (p = 0.043) and low birth weight (p = 0.011). With respect to colonization with multidrug-resistant enterococci, risk factors were prematurity (p = 0.0006), low birth weight (p < 0.0001) and prepartal antibiotic treatment (p = 0.019). Using logistic regression, we determined that gestational age was the only parameter significantly correlated with multidrug-resistant enterococci colonization. No infection with enterococci or multidrugresistant enterococci in the infants was detected. The outcome of infants with and without enterococcal colonization was the same with respect to death, necrotizing enterocolitis, intracerebral hemorrhage and bronchopulmonary dysplasia.</p> <p>Conclusion</p> <p>In neonatal intensive care units, an infant's susceptibility to early colonization with enterococci in general, and his or her risk for colonization with multidrug-resistant enterococci in particular, is increased in preterm newborns, especially during the winter/spring months. The prepartal use of antibiotics with no known activity against enterococci appears to increase the risk for colonization with multidrug-resistant enterococci.</p

Comparison of birth weights of infants either colonized or not colonized with (A) enterococci and (B) multidrug-resistant enterococci in meconium or surveillance cultures

<p><b>Copyright information:</b></p><p>Taken from "Enterococcal colonization of infants in a neonatal intensive care unit: associated predictors, risk factors and seasonal patterns"</p><p>http://www.biomedcentral.com/1471-2334/7/107</p><p>BMC Infectious Diseases 2007;7():107-107.</p><p>Published online 16 Sep 2007</p><p>PMCID:PMC2077867.</p><p></p> Boxes extend from the 25th to the 75th percentile, with a line at the median (50th percentile) and whiskers show the highest and the lowest birth weights. The p values refer to the comparison of the median values using the Mann Whitney test

Comparison of gestational age of infants either colonized or not colonized with (A) enterococci and (B) multidrug-resistant enterococci in meconium or surveillance cultures

<p><b>Copyright information:</b></p><p>Taken from "Enterococcal colonization of infants in a neonatal intensive care unit: associated predictors, risk factors and seasonal patterns"</p><p>http://www.biomedcentral.com/1471-2334/7/107</p><p>BMC Infectious Diseases 2007;7():107-107.</p><p>Published online 16 Sep 2007</p><p>PMCID:PMC2077867.</p><p></p> Boxes extend from the 25th to the 75th percentile, with a line at the median (50th percentile) and whiskers show the highest and the lowest gestational ages. The p values refer to the comparison of the median values using the Mann Whitney test