How Clean is the Clean Room?

In order to limit contamination and protect the integrity of search-for-life missions, spacecraft assembly clean rooms should be free of microorganisms to the extent that planetary protection guidelines require of the mission. This study monitored the bioburden of the clean room in which the Mars-destined InSight lander was being assembled. Samples of ten locations inside the clean room and one location outside were taken at monthly intervals, starting in March 2014 and scheduled to end in September 2014. Bioburden was determined using qPCR and ATP analyses with qPCR targating 16S rRNA gene copy number and ATP targating metabolic activity of microbes. Samples were treated with propidium monoazide (PMA) to selectively distinguish between viable and non-viable cells prior to DNA extraction and qPCR. Analyses of total ATP, internal ATP, and ATP as measured by a handheld device were done. Results from the first three samplings shows that the amount of both untreated and PMA treated DNA decreased significantly between the first sampling (3/21/2014) and the second sampling (5/13/2014), possibly as a result of increased assembly activity and rigorous cleaning practices. Results of the ATP analyses showed no significant changes in total ATP, but internal and handheld ATP decreased between the second and third samplings. The preliminary results indicate that the bioburden of the clean room changes inversely as a result of assembly activity and cleaning efforts. The clean room will continue to be monitored through an additional three months

Does the Production of Isoprene Affect the Productivity of Poplars?

Poplar trees are known to produce a chemical called isoprene that plays a complex, and not fully understood, role in the chemical process of photosynthesis. Understanding why plants produce isoprene and under what conditions will help scientists make more accurate predictions about poplars’ photosynthetic capabilities in future climates. What benefit could isoprene provide a plant? The literature suggests its production could help plants tolerate heat stress. We studied two genetic lines of trees in a common garden of Populus, one line with the gene for producing isoprene and a second line without that gene. We subjected some trees of each line to low water conditions to investigate if isoprene played a role in allowing plants to cope with water stress. We then compared the ability of these 4 treatment groups of poplars to photosynthesize over a range of temperatures. Poplars with and without isoprene showed similar rates of photosynthesis over the range of temperatures measured. Poplars subjected to low water conditions and poplars with normal water conditions also recorded similar rates of photosynthesis. This suggests that isoprene does not offer a photosynthetic benefit, and also that the low water conditions may not have triggered a water stressed state in the poplars. However, the poplars’ rate of photosynthesis differed between morning and afternoon, suggesting that time of day could play a role in photosynthesis. Future work is needed to understand how the influence of time of day on photosynthesis may overshadow any differences due to isoprene production

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

Justify your alpha

Benjamin et al. proposed changing the conventional “statistical significance” threshold (i.e.,the alpha level) from p ≤ .05 to p ≤ .005 for all novel claims with relatively low prior odds. They provided two arguments for why lowering the significance threshold would “immediately improve the reproducibility of scientific research.” First, a p-value near .05provides weak evidence for the alternative hypothesis. Second, under certain assumptions, an alpha of .05 leads to high false positive report probabilities (FPRP2 ; the probability that a significant finding is a false positive

WSES guidelines for management of Clostridium difficile infection in surgical patients

In the last two decades there have been dramatic changes in the epidemiology of Clostridium difficile infection (CDI), with increases in incidence and severity of disease in many countries worldwide. The incidence of CDI has also increased in surgical patients. Optimization of management of C difficile, has therefore become increasingly urgent. An international multidisciplinary panel of experts prepared evidenced-based World Society of Emergency Surgery (WSES) guidelines for management of CDI in surgical patients.Peer reviewe

Chemical kinetics in an atmospheric pressure helium plasma containing humidity

Atmospheric pressure plasmas are sources of biologically active oxygen and nitrogen species, which makes them potentially suitable for the use as biomedical devices. Here, experiments and simulations are combined to investigate the formation of the key reactive oxygen species, atomic oxygen (O) and hydroxyl radicals (OH), in a radio-frequency driven atmospheric pressure plasma jet operated in humidified helium. Vacuum ultra-violet high-resolution Fourier-transform absorption spectroscopy and ultra-violet broad-band absorption spectroscopy are used to measure absolute densities of O and OH. These densities increase with increasing H 2 O content in the feed gas, and approach saturation values at higher admixtures on the order of 3 × 10 14 cm −3 for OH and 3 × 10 13 cm −3 for O. Experimental results are used to benchmark densities obtained from zero-dimensional plasma chemical kinetics simulations, which reveal the dominant formation pathways. At low humidity content, O is formed from OH + by proton transfer to H 2 O, which also initiates the formation of large cluster ions. At higher humidity content, O is created by reactions between OH radicals, and lost by recombination with OH. OH is produced mainly from H 2 O + by proton transfer to H 2 O and by electron impact dissociation of H 2 O. It is lost by reactions with other OH molecules to form either H 2 O + O or H 2 O 2 . Formation pathways change as a function of humidity content and position in the plasma channel. The understanding of the chemical kinetics of O and OH gained in this work will help in the development of plasma tailoring strategies to optimise their densities in applications

Justify your alpha

In response to recommendations to redefine statistical significance to p ≤ .005, we propose that researchers should transparently report and justify all choices they make when designing a study, including the alpha level

WSES guidelines for management of Clostridium difficile infection in surgical patients

In the last two decades there have been dramatic changes in the epidemiology of Clostridium difficile infection (CDI), with increases in incidence and severity of disease in many countries worldwide. The incidence of CDI has also increased in surgical patients. Optimization of management of C difficile, has therefore become increasingly urgent. An international multidisciplinary panel of experts prepared evidenced-based World Society of Emergency Surgery (WSES) guidelines for management of CDI in surgical patients