Tumbleweeds and airborne gravitational noise sources for LIGO

Gravitational-wave detectors are sensitive not only to astrophysical gravitational waves, but also to the fluctuating Newtonian gravitational forces of moving masses in the ground and air around the detector. This paper studies the gravitational effects of density perturbations in the atmosphere, and from massive airborne objects near the detector. These effects were previously considered by Saulson; in this paper I revisit these phenomena, considering transient atmospheric shocks, and the effects of sound waves or objects colliding with the ground or buildings around the test masses. I also consider temperature perturbations advected past the detector as a source of gravitational noise. I find that the gravitational noise background is below the expected noise floor even of advanced interferometric detectors, although only by an order of magnitude for temperature perturbations carried along turbulent streamlines. I also find that transient shockwaves in the atmosphere could potentially produce large spurious signals, with signal-to-noise ratios in the hundreds in an advanced interferometric detector. These signals could be vetoed by means of acoustic sensors outside of the buildings. Massive wind-borne objects such as tumbleweeds could also produce gravitational signals with signal-to-noise ratios in the hundreds if they collide with the interferometer buildings, so it may be necessary to build fences preventing such objects from approaching within about 30m of the test masses.Comment: 15 pages, 10 PostScript figures, uses REVTeX4.cls and epsfig.st

Hydrogen adsorption and cohesive energy of single-walled carbon nanotubes

Hydrogen adsorption on crystalline ropes of carbon single-walled nanotubes (SWNT) was found to exceed 8 wt.%, which is the highest capacity of any carbon material. Hydrogen is first adsorbed on the outer surfaces of the crystalline ropes. At pressures higher than about 40 bar at 80 K, however, a phase transition occurs where there is a separation of the individual SWNTs, and hydrogen is physisorbed on their exposed surfaces. The pressure of this phase transition provides a tube-tube cohesive energy for much of the material of 5 meV/C atom. This small cohesive energy is affected strongly by the quality of crystalline order in the ropes

Interventions to prevent non-critical care hospital acquired pneumonia – a systematic review

Background: Hospital-acquired pneumonia is a significant burden to healthcare systems around the world. Although there is a considerable body of evidence on prevention of ventilator associated pneumonia, less is known about strategies to prevent hospital-acquired pneumonia in non-critical care settings. Objective: To systematically review the randomised controlled trial evidence for prevention of hospital-acquired pneumonia in non-critical care settings. Methods: We searched EMBASE, CINAHL+, MEDLINE and the Cochrane Library. Seventeen different searches were conducted in parallel through each database. Studies were included if they were randomised controlled trials reporting hospital-acquired pneumonia as an endpoint. Studies were excluded if they were performed in critical care or community settings. All studies published up to the end of December 2014 were considered, with no language restrictions. Data were independently extracted by two authors and the Delphi risk of bias tool was applied to assess trial quality. Results: Five thousand one hundred and one titles were identified across 17 searches. Only two studies were eligible for inclusion in the final review, one from a search of physical therapy interventions and one from a search of enteral feeding. The heterogeneity of the interventions did not permit meta-analysis. One trial suggested possible benefits to early mobilisation; the other trial suggested no benefit or harm from early enteral feeding via nasogastric tube. Both trials enrolled patients with acute stroke. No trials in non-stroke, non-critical care populations were eligible for inclusion in the review. Conclusions: There is currently insufficient trial evidence on preventing non-critical care hospital-acquired pneumonia to make recommendations on practice.</p

Volcanic air pollution and human health: recent advances and future directions

Volcanic air pollution from both explosive and effusive activity can affect large populations as far as thousands of kilometers away from the source, for days to decades or even centuries. Here, we summarize key advances and prospects in the assessment of health hazards, effects, risk, and management. Recent advances include standardized ash assessment methods to characterize the multiple physicochemical characteristics that might influence toxicity; the rise of community-based air quality monitoring networks using low-cost gas and particulate sensors; the development of forecasting methods for ground-level concentrations and associated public advisories; the development of risk and impact assessment methods to explore health consequences of future eruptions; and the development of evidence-based, locally specific measures for health protection. However, it remains problematic that the health effects of many major and sometimes long-duration eruptions near large populations have gone completely unmonitored. Similarly, effects of prolonged degassing on exposed populations have received very little attention relative to explosive eruptions. Furthermore, very few studies have longitudinally followed populations chronically exposed to volcanic emissions; thus, knowledge gaps remain about whether chronic exposures can trigger development of potentially fatal diseases. Instigating such studies will be facilitated by continued co-development of standardized protocols, supporting local study teams and procuring equipment, funding, and ethical permissions. Relationship building between visiting researchers and host country academic, observatory, and agency partners is vital and can, in turn, support the effective communication of health impacts of volcanic air pollution to populations, health practitioners, and emergency managers

Evolution of rarefaction pulses into vortex rings

The two-dimensional solitary waves of the Gross-Pitaevskii equation in the Kadomtsev-Petviashvili limit are unstable with respect to three-dimensional perturbations. We elucidate the stages in the evolution of such solutions subject to perturbations perpendicular to the direction of motion. Depending on the energy (momentum) and the wavelength of the perturbation different types of three-dimensional solutions emerge. In particular, we present new periodic solutions having very small energy and momentum per period. These solutions also become unstable and this secondary instability leads to vortex ring nucleation.Comment: 5 pages, 5 figure

Russia-UK collaboration in paleontology: past, present, and future

There is a long history of collaboration between Russia and the United Kingdom in paleontology. This began, arguably, in 1821, with the seminal work by William Fox-Strangways, who produced a geological map of the area around St Petersburg. Most famously, Roderick Murchison carried out extensive surveying and observations throughout European Russia in 1840 and 1841, and published a major monograph on geology and paleontology of European Russia in 1845. Since then, and continuing today, there have been many fruitful collaborations on Precambrian life, Paleozoic marine organisms, terrestrialization of plants and vertebrates, the Permian–Triassic mass extinction, fossil mammals, human evolution, and conservation paleobiology

Ultrafine hydrogen storage powders

A method of making hydrogen storage powder resistant to fracture in service involves forming a melt having the appropriate composition for the hydrogen storage material, such, for example, LaNi5 and other AB5 type materials and AB5+x materials, where x is from about -2.5 to about +2.5, including x=0, and the melt is gas atomized under conditions of melt temperature and atomizing gas pressure to form generally spherical powder particles. The hydrogen storage powder exhibits improved chemcial homogeneity as a result of rapid solidfication from the melt and small particle size that is more resistant to microcracking during hydrogen absorption/desorption cycling. A hydrogen storage component, such as an electrode for a battery or electrochemical fuel cell, made from the gas atomized hydrogen storage material is resistant to hydrogen degradation upon hydrogen absorption/desorption that occurs for example, during charging/discharging of a battery. Such hydrogen storage components can be made by consolidating and optionally sintering the gas atomized hydrogen storage powder or alternately by shaping the gas atomized powder and a suitable binder to a desired configuration in a mold or die

Association between GDF-15 levels and changes in vascular and physical function in older patients with hypertension

Background: Growth differentiation factor-15 (GDF-15) may be a biomarker of disease, protective response and/or prognosis, in older people with hypertension. Aims: To correlate baseline GDF-15 levels with physical and vascular health data in this population. Methods: Baseline blood samples were analysed using a GDF-15 ELISA assay kit. Correlations with baseline and 12-month outcome data, including measures of physical and vascular function, were performed. Results: A total of 147 individuals, mean age 76.8 ± 4.7 years, were included. 77 (52 %) were male. Baseline log10GDF-15 showed significant correlations with age (r = 0.37, p &lt; 0.001), total cholesterol (r = −0.33, p &lt; 0.001) and 6-min walking distance (r = −0.37, p &lt; 0.001). Age remained significantly associated with log10GDF-15 in multivariable analysis (beta = −0.29, p = 0.001). Baseline log10GDF-15 was significantly associated with decline in 6-min walk distance over 12 months (beta = −0.27, p = 0.01) in multivariable models. No significant correlations were seen with changes in vascular function over 12 months. Conclusion: Baseline GDF-15 predicts declining physical, but not vascular, function in our population

Opportunities for refinement in neuroscience: Indicators of wellness and post-operative pain in laboratory macaques

Being able to assess pain in nonhuman primates undergoing biomedical procedures is important for preventing and alleviating pain, and for developing better guidelines to minimise the impacts of research on welfare in line with the 3Rs principle of Refinement. Nonhuman primates are routinely used biomedical models however it remains challenging to recognise negative states, including pain, in these animals. This study aimed to identify behavioural and facial changes that could be used as pain or general wellness indicators in the rhesus macaque (Macaca mulatta). Thirty-six macaques scheduled for planned neuroscience procedures were opportunistically monitored at four times: Pre-Operative (PreOp), Post-Operative (PostOp) once the effects of anaesthesia had dissipated, Pre-Analgesia (PreAn) on the subsequent morning prior to repeating routine analgesic treatment, and Post-Analgesia (PostAn) following administration of analgesia. Pain states were expected to be absent in PreOp, moderate in PreAn, and mild or absent in PostOp and PostAn when analgesia had been administered. Three potential pain indicators were identified: lip tightening and chewing, which were most likely to occur in PreAn, and running which was least likely in PreAn. Arboreal behaviour indicated general wellness, while half-closed eyes, leaning of the head or body shaking indicated the opposite. Despite considerable individual variation, behaviour and facial expressions could offer important indicators of pain and wellness and should be routinely quantified, and appropriate interventions applied to prevent or alleviate pain, and promote positive welfare

Candidate planetary nebulae in the IPHAS photometric catalogue

Original article can be found at: http://www.aanda.org/ Copyright European Southern Observatory. DOI: 10.1051/0004-6361/200912002Context. We have carried out a semi-automated search for planetary nebulae (PNe) in the INT photometric H-alpha survey (IPHAS) catalogue. We present the PN search and the list of selected candidates. We cross correlate the selected candidates with a number of existing infrared galactic surveys in order to gain further insight into the nature of the candidates. Spectroscopy of a subset of objects is used to estimate the number of PNe present in the entire candidate list. Aims. The overall aim of the IPHAS PN project is to carry out a deep census of PNe in the northern Galactic plane, an area where PN detections are clearly lacking. Methods. The PN search is carried out on the IPHAS photometric catalogue. The candidate selection is based on the IPHAS and 2MASS/UKIDSS colours of the objects and the final candidate selection is made visually. Results. From the original list of ~600 million IPHAS detections we have selected a total of 1005 objects. Of these, 224 are known objects, leaving us with 781 PN candidates. Based on the initial follow-up spectroscopy, we expect the list to include very young and proto-PNe in addition to genuine, normal PNe (~16%) and emission line objects other than PNe. We present additional criteria to select the most probable PN candidates from our candidate list.Peer reviewe