Corrigendum to "Technical note: Consistent calculation of aquatic gross production from oxygen triple isotope measurements" published in Biogeosciences, 8, 1793–1811, 2011

No abstract available

Technical note: Consistent calculation of aquatic gross production from oxygen triple isotope measurements

Oxygen triple isotope measurements can be used to calculate aquatic gross oxygen production rates. Past studies have emphasised the appropriate definition of the 17O excess and often used an approximation to derive production rates from the 17O excess. Here, I show that the calculation can be phrased more consistently and without any approximations using the relative 17O/16O and 18O/16O isotope ratio differences (delta values) directly. I call this the "dual delta method". The 17O excess is merely a mathematical construct and the derived production rate is independent of its definition, provided all calculations are performed with a consistent definition. I focus on the mixed layer, but also show how time series of triple isotope measurements below the mixed layer can be used to derive gross production. In the calculation of mixed layer productivity, I explicitly include isotopic fractionation during gas invasion and evasion, which requires the oxygen supersaturation s to be measured as well. I also suggest how bubble injection could be considered in the same mathematical framework. I distinguish between concentration steady state and isotopic steady state and show that only the latter needs to be assumed in the calculation. It is even possible to derive an estimate of the net production rate in the mixed layer that is independent of the assumption of concentration steady state. I review measurements of the parameters required for the calculation of gross production rates and show how their systematic uncertainties as well as the use of different published calculation methods can cause large variations in the production rates for the same underlying isotope ratios. In particular, the 17O excess of dissolved O2 in equilibrium with atmospheric O2 and the 17O excess of photosynthetic O2 need to be re-measured. Because of these uncertainties, all calculation parameters should always be fully documented and the measured relative isotope ratio differences as well as the oxygen supersaturation should be permanently archived, so that improved measurements of the calculation parameters can be used to retrospectively improve production rates

Combat Related Post Traumatic Stress Disorder in Veterans of Operation Enduring Freedom and Operation Iraqi Freedom: A Review of the Literature

The conflict Afghanistan and Iraq have now taken their places amongst the longest running wars in American history. As many Americans return from military service, the prevalence of combat related post traumatic stress syndrome is estimated to be as high as 30% or returning veterans. This debilitating condition impacts the individual, their family, and their community in significant ways. A variety of treatments including Cognitive Behavioral Therapy, Prolonged Exposure Therapy, and Virtual Reality Therapy have all been cited as effective interventions for this population. As our nation continues military conflict in the middle east, clinicians need to be prepared to screen and treat individuals suffering from combat related PTSD

Three-body spin-orbit forces from chiral two-pion exchange

Using chiral perturbation theory, we calculate the density-dependent spin-orbit coupling generated by the two-pion exchange three-nucleon interaction involving virtual $\Delta$-isobar excitation. From the corresponding three-loop Hartree and Fock diagrams we obtain an isoscalar spin-orbit strength $F_{\rm so}(k_f)$ which amounts at nuclear matter saturation density to about half of the empirical value of $90$MeVfm$^5$. The associated isovector spin-orbit strength $G_{\rm so}(k_f)$ comes out about a factor of 20 smaller. Interestingly, this three-body spin-orbit coupling is not a relativistic effect but independent of the nucleon mass $M$. Furthermore, we calculate the three-body spin-orbit coupling generated by two-pion exchange on the basis of the most general chiral $\pi\pi NN$-contact interaction. We find similar (numerical) results for the isoscalar and isovector spin-orbit strengths $F_{\rm so}(k_f)$ and $G_{\rm so}(k_f)$ with a strong dominance of the p-wave part of the $\pi\pi NN$-contact interaction and the Hartree contribution.Comment: 8 pages, 4figure, published in : Physical Review C68, 054001 (2003

Making electromagnetic wavelets

Electromagnetic wavelets are constructed using scalar wavelets as superpotentials, together with an appropriate polarization. It is shown that oblate spheroidal antennas, which are ideal for their production and reception, can be made by deforming and merging two branch cuts. This determines a unique field on the interior of the spheroid which gives the boundary conditions for the surface charge-current density necessary to radiate the wavelets. These sources are computed, including the impulse response of the antenna.Comment: 29 pages, 4 figures; minor corrections and addition

Dichroic subreflector for Rosman 2

The dichronic subreflector for the Rosman 2 dish antenna is described. Tests were conducted to make focusing adjustments, to measure the system parameters indicative of a focused condition for the Cassegrain feed, and to determine losses for the focal point feeds due to the presence of the dichroic

Using dissolved oxygen concentrations to determine mixed layer depths in the Bellingshausen Sea

Concentrations of oxygen (O<sub>2</sub>) and other dissolved gases in the oceanic mixed layer are often used to calculate air-sea gas exchange fluxes. The mixed layer depth (<i>z</i><sub>mix</sub>) may be defined using criteria based on temperature or density differences to a reference depth near the ocean surface. However, temperature criteria fail in regions with strong haloclines such as the Southern Ocean where heat, freshwater and momentum fluxes interact to establish mixed layers. Moreover, the time scales of air-sea exchange differ for gases and heat, so that <i>z</i><sub>mix</sub> defined using oxygen may be different than <i>z</i><sub>mix</sub> defined using temperature or density. Here, we propose to define an O<sub>2</sub>-based mixed layer depth, <i>z</i><sub>mix</sub>(O<sub>2</sub>), as the depth where the relative difference between the O<sub>2</sub> concentration and a reference value at a depth equivalent to 10 dbar equals 0.5 %. This definition was established by analysis of O<sub>2</sub> profiles from the Bellingshausen Sea (west of the Antarctic Peninsula) and corroborated by visual inspection. Comparisons of <i>z</i><sub>mix</sub>(O<sub>2</sub>) with <i>z</i><sub>mix</sub> based on potential temperature differences, i.e., <i>z</i><sub>mix</sub>(0.2 °C) and <i>z</i><sub>mix</sub>(0.5 °C), and potential density differences, i.e., <i>z</i><sub>mix</sub>(0.03 kg m<sup>−3</sup>) and <i>z</i><sub>mix</sub>(0.125 kg m<sup>−3</sup>), showed that <i>z</i><sub>mix</sub>(O<sub>2</sub>) closely follows <i>z</i><sub>mix</sub>(0.03 kg m<sup>−3</sup>). Further comparisons with published <i>z</i><sub>mix</sub> climatologies and <i>z</i><sub>mix</sub> derived from World Ocean Atlas 2005 data were also performed. To establish <i>z</i><sub>mix</sub> for use with biological production estimates in the absence of O<sub>2</sub> profiles, we suggest using <i>z</i><sub>mix</sub>(0.03 kg m<sup>−3</sup>), which is also the basis for the climatology by de Boyer Montégut et al. (2004)

Understanding residents’ capacities to support evacuated populations : A study of earthquake and tsunami evacuation for Napier Hill, Napier, Aotearoa New Zealand.

Due to a large regional subduction zone (the Hikurangi subduction zone) and localised faults, Napier City located on the East Coast of Aotearoa/New Zealand is vulnerable to earthquake and tsunami events. On feeling a long or strong earthquake people will need to evacuate immediately inland or to higher ground to avoid being impacted by a tsunami, of which the first waves could start to arrive within 20 minutes (based on the Hikurangi earthquake and tsunami scenario presented in Power et al., 2018). Napier Hill is one such area of higher land, and it is estimated that up to 12,000 people could evacuate there in the 20 minutes following a long or strong earthquake. To understand the capacity of Napier Hill residents to support evacuees, three focus groups were held with a diverse sample of residents from Napier Hill on 21 and 22 July 2019. A follow up email was sent to all participants a week after the focus groups, containing a link to a short six question survey, which was completed by 68 people, most of whom were additional to the focus group attendees. Data from the focus groups and the survey was analysed qualitatively using thematic analysis. The findings highlight that in general people were happy to host evacuees and offer support if they were in a position to do so. However, key issues in being able to offer support included the likely lack of resources available after a disaster, ranging from basic needs though to agency support. The research findings will directly inform Napier City Council and Hawke’s Bay Civil Defence Emergency Management Group’s planning for future readiness and response by providing valuable insights for evacuation planningfalseWellingtonHawke's Bay Civil Defence Emergency Management Grou

The cosomological evolution of the environments of powerful radio galaxies

We present the results from the analysis of 26 extragalactic radio sources of type FRII which were observed with the VLA at 5 GHz and around the 1.4 GHz band. The sources were selected to have redshifts in the range $0.3<z<1.3$, radio powers between $6.9 \times 10^{26} {\rm WHz^{-1}}<P_{151 {\rm MHz}}<1.3 \times 10^{28} {\rm WHz^{-1}}$ and angular size $\theta \ge 10''$. We found that the depolarisation and the rms variations in the rotation measure increased with redshift. The flux values obtained from the observations were used to derive by means of analytical modelling the jet--power, density of the central environment, age of the source and its lobe pressure and the results were then compared with the observations. We find no significant correlations with the density parameter suggesting that the depolarisation and the rms variations in the rotation measure are indicative of the environment becoming more disordered rather than denser. The age and size of a source are correlated and both were found to be independent of redshift and radio--power. Jet--power strongly correlated with the radio--power. The lobe pressure was found to be anti--correlated with size which could explain why there are no sources beyond a few Mpc in size. We found no significant correlation between size and density which demonstrates that the sample is a fair representation of the population.Comment: 2 pages, Cozumel AGN 2003 conference proceeding