Explicit solution of the linearized Einstein equations in TT gauge for all multipoles

We write out the explicit form of the metric for a linearized gravitational wave in the transverse-traceless gauge for any multipole, thus generalizing the well-known quadrupole solution of Teukolsky. The solution is derived using the generalized Regge-Wheeler-Zerilli formalism developed by Sarbach and Tiglio.Comment: 9 pages. Minor corrections, updated references. Final version to appear in Class. Quantum Gra

Technical Note: Quantitative long-term measurements of VOC concentrations by PTR-MS ? measurement, calibration, and volume mixing ratio calculation methods

International audienceProton transfer reaction mass spectrometry (PTR-MS) is a technique for online measurements of atmospheric concentrations, or volume mixing ratios, of volatile organic compounds (VOCs). The aim of this paper is to give a detailed description of our measurement, calibration, and volume mixing ratio calculation methods, which have been designed for long-term stand-alone field measurements by PTR-MS. We also show how the information obtained from a calibration can be used to determine the instrument specific relative transmission curve, which enables quantitative mixing ratio calculation for VOCs which are not present in a calibration gas standard. To illustrate the functionality of our measurement, calibration, and calculation methods, we present a one-month period of ambient mixing ratio data measured in a boreal forest ecosystem at the SMEAR II station in southern Finland. During the measurement period 27 March?26 April 2007, the hourly averages of mixing ratios were 0.1?0.5 ppbv for formaldehyde, 0.2?3.0 ppbv for methanol, 0.04?0.39 ppbv for benzene, and 0.03?1.25 ppbv for monoterpenes

Hydrocarbon fluxes above a Scots pine forest canopy: Measurements and modeling

International audienceWe measured the fluxes of several hydrocarbon species above a Scots pine (Pinus sylvestris) stand using disjunct eddy covariance technique with proton transfer reaction ? mass spectrometry. The measurements were conducted during four days in July at SMEAR II research station in Hyytiälä, Finland. Compounds which showed significant emission fluxes were methanol, acetaldehyde, acetone, and monoterpenes. A stochastic Lagrangian transport model with simple chemical degradation was applied to assess the sensitivity of the above canopy fluxes to chemistry. According to the model, the chemical degradation had a minor effect on the fluxes measured in this study but has a major effect on the vertical flux profiles of more reactive compounds, such as sesquiterpenes. The monoterpene fluxes followed the traditional exponential temperature dependent emission algorithm but were considerably higher than the fluxes measured before at the same site. The normalized emission potential (30°C) was 2.5 ?g gdw?1 h?1 obtained using the temperature dependence coefficient of 0.09°C?1

Anthropogenic and biogenic influence on VOC fluxes at an urban background site in Helsinki, Finland

We measured volatile organic compounds (VOCs), carbon dioxide (CO2) and carbon monoxide (CO) at an urban background site near the city centre of Helsinki, Finland, northern Europe. The VOC and CO2 measurements were obtained between January 2013 and September 2014 whereas for CO a shorter measurement campaign in April-May 2014 was conducted. Both anthropogenic and biogenic sources were identified for VOCs in the study. Strong correlations between VOC fluxes and CO fluxes and traffic rates indicated anthropogenic source of many VOCs. The VOC with the highest emission rate to the atmosphere was methanol, which originated mostly from traffic and other anthropogenic sources. The traffic was also a major source for aromatic compounds in all seasons whereas isoprene was mostly emitted from biogenic sources during summer. Some amount of traffic-related isoprene emissions were detected during other seasons but this might have also been an instrumental contamination from cycloalkane products. Generally, the observed VOC fluxes were found to be small in comparison with previous urban VOC flux studies. However, the differences were probably caused by lower anthropogenic activities as the CO2 fluxes were also relatively small at the site.Peer reviewe

Constraint-preserving boundary treatment for a harmonic formulation of the Einstein equations

We present a set of well-posed constraint-preserving boundary conditions for a first-order in time, second-order in space, harmonic formulation of the Einstein equations. The boundary conditions are tested using robust stability, linear and nonlinear waves, and are found to be both less reflective and constraint preserving than standard Sommerfeld-type boundary conditions.Comment: 18 pages, 7 figures, accepted in CQ

Measurements of hydrocarbon emissions from a boreal fen using the REA technique

Fluxes of biogenic volatile organic compounds (VOC) and methane were measured above a boreal fen. Vegetation on the fen is dominated by Sphagnum mosses and sedges. A relaxed eddy accumulation (REA) system with dynamic deadband was designed and constructed for the measurements. Methane, C-2-C-6 hydrocarbons and some halogenated hydrocarbons were analysed from the samples by gas chromatographs equipped with FID and ECD. A significant flux of isoprene and methane was detected during the growing seasons. Isoprene emission was found to follow the common isoprene emission algorithm. Average standard emission potential of isoprene was 680 mu g m(-2) h(-1). Fluxes of other non-methane hydrocarbons were below detection limit.Fluxes of biogenic volatile organic compounds (VOC) and methane were measured above a boreal fen. Vegetation on the fen is dominated by Sphagnum mosses and sedges. A relaxed eddy accumulation (REA) system with dynamic deadband was designed and constructed for the measurements. Methane, C-2-C-6 hydrocarbons and some halogenated hydrocarbons were analysed from the samples by gas chromatographs equipped with FID and ECD. A significant flux of isoprene and methane was detected during the growing seasons. Isoprene emission was found to follow the common isoprene emission algorithm. Average standard emission potential of isoprene was 680 mu g m(-2) h(-1). Fluxes of other non-methane hydrocarbons were below detection limit.Fluxes of biogenic volatile organic compounds (VOC) and methane were measured above a boreal fen. Vegetation on the fen is dominated by Sphagnum mosses and sedges. A relaxed eddy accumulation (REA) system with dynamic deadband was designed and constructed for the measurements. Methane, C-2-C-6 hydrocarbons and some halogenated hydrocarbons were analysed from the samples by gas chromatographs equipped with FID and ECD. A significant flux of isoprene and methane was detected during the growing seasons. Isoprene emission was found to follow the common isoprene emission algorithm. Average standard emission potential of isoprene was 680 mu g m(-2) h(-1). Fluxes of other non-methane hydrocarbons were below detection limit.Peer reviewe

A stochastic evolutionary model for capturing human dynamics

The recent interest in human dynamics has led researchers to investigate the stochastic processes that explain human behaviour in various contexts. Here we propose a generative model to capture the dynamics of survival analysis, traditionally employed in clinical trials and reliability analysis in engineering. We derive a general solution for the model in the form of a product, and then a continuous approximation to the solution via the renewal equation describing age-structured population dynamics. This enables us to model a wide range of survival distributions, according to the choice of the mortality distribution. We provide empirical evidence for the validity of the model from a longitudinal data set of popular search engine queries over 114 months, showing that the survival function of these queries is closely matched by the solution for our model with power-law mortality

Terpenoid emissions from fully grown east Siberian Larix cajanderi trees

Peer reviewe

Acute hormonal findings after aneurysmal subarachnoid hemorrhage - report from a single center

Purpose: The aim was to assess anterior pituitary hormone levels during the acute phase of aneurysmal subarachnoid hemorrhage (aSAH) and analyze the possible association with the clinical condition and outcome. Material and methods: Forty patients with aSAH whose aneurysm was secured by endovascular coiling were enrolled. Basal secretions of cortisol, testosterone, luteinizing hormone (LH), prolactin (PRL), and sex hormone binding globulin (SHBG) levels were measured up to 14 days after the incident. Results: The main finding was that hypocortisolism was rare whereas testosterone deficiency was common in male patients. Furthermore, various other hormone deviations were frequent and there was wide interindividual variability. We found no association between delayed cerebral ischemia (DCI), outcome of the patients or aneurysm location, and hormone abnormalities, while both Hunt & Hess and Fisher grade were associated with low PRL levels. Hunt & Hess 5 was associated with low PRL concentration when compared to grades 1 (OR = 4.81, 95% CI 1.15-20.14, p = 0.03), 3 (OR 7.73, 95% CI 1.33-45.01, p = 0.02), and 4 (OR = 6.86 95% CI 1.28-26.83, p = 0.02). Fisher grade 4 was associated with low PRL concentration when compared to grades 3 (OR 3.37, 95% CI 1.06-10.73, p = 0.03) and 2 (OR 9.71, 95% CI 1.22-77.10, p = 0.04). Conclusion: Deviations from normal and huge interindividual differences are common in hormone levels during the acute phase of aSAH. Routine assessment of anterior pituitary function in the acute phase of aSAH is not warranted. During the follow-up in the outpatient clinic, hormone concentrations were not measured, which would have brought a more long-term perspective into our findings.Peer reviewe