Sea level data and techniques for detecting vertical crustal movements

An attempt is made to survey problems, requirements, and the outlook for the future in the study of sea level time series so as to determine the relative movement of land and sea levels. The basic aim is to eliminate from the record the contributions from whatever marine dynamic phenomena respond to treatment, allowing the secular element to be identified with optimum clarity. Nevertheless the concept of sea level perturbation varies according to regional experience. The recent work of the Permanent Service for Mean Sea Level helps to eliminate geodetic noise from the series and makes it possible, perhaps, to treat the global mean sea level data bank so as to define eustatic changes in ocean volume which, in the present context, may be regarded as the final goal, allowing the identification of vertical crustal motion itself

On Anomalous Tides in Australian Waters

The Coral Sea has been identified as the location of an anomaly in the semidiurnal tidal band with an apparently sharp local resonance in the vicinity of the frequency of L2. It is here shown that such a simple resonance does not exist but that the anomaly has a gravitational origin which may indicate a more complex mechanism. Long spans of tidal observations from Cairns, Townsville and nearby ports are analysed in an attempt to estimate the frequency response of the gravitational tide across the semi-diurnal spectral band. The identification of the response function is assisted by the treatment of perturbing energy from non-gravitational sources, in particular those associated with shallow water non-linear interaction. At both stations two terms emerge which are seen to be greatly amplified, one with an argument number (2-10000) is very close to N2 in the frequency spectrum while the other (210000) is near to L2. Together they form a conjugate pair of tidal lines about M2 and they are separated from their more conventional neighbours by only one cycle in 8.85 years, the period of the lunar perigee. The anomaly is discussed, and the suggestion is made that the amplification of these terms, (2±10000), may be due to their spatial distribution which is different from those of the principal tides, so exciting specific forcing functions in the response of the oceanic scale system

Fluorine abundances in planetary nebulae

We have determined fluorine abundances from the F II 4789 and F IV 4060 nebular emission lines for a sample of planetary nebulae (PNe). Our results show that fluorine is generally overabundant in PNe, thus providing new evidence for the synthesis of fluorine in asymptotic giant branch (AGB) stars. [F/O] is found to be positively correlated with the C/O abundance ratio, in agreement with the predictions of theoretical models of fluorine production in thermally pulsing AGB stars. A large enhancement of fluorine is observed in the Wolf-Rayet PN NGC 40, suggesting that high mass-loss rates probably favor the survival of fluorine.Comment: 4 pages, 3 figures, accepted for publication in ApJ Letter

On Collisionless Electron-Ion Temperature Equilibration in the Fast Solar Wind

We explore a mechanism, entirely new to the fast solar wind, of electron heating by lower hybrid waves to explain the shift to higher charge states observed in various elements in the fast wind at 1 A.U. relative to the original coronal hole plasma. This process is a variation on that previously discussed for two temperature accretion flows by Begelman & Chiueh. Lower hybrid waves are generated by gyrating minor ions (mainly alpha-particles) and become significant once strong ion cyclotron heating sets in beyond 1.5 R_sun. In this way the model avoids conflict with SUMER electron temperature diagnostic measurements between 1 and 1.5 R_sun. The principal requirement for such a process to work is the existence of density gradients in the fast solar wind, with scale length of similar order to the proton inertial length. Similar size structures have previously been inferred by other authors from radio scintillation observations and considerations of ion cyclotron wave generation by global resonant MHD waves.Comment: 32 pages including 11 figures, 4 tables, accepted by Ap

Bubbles and Filaments: Stirring a Cahn-Hilliard Fluid

The advective Cahn-Hilliard equation describes the competing processes of stirring and separation in a two-phase fluid. Intuition suggests that bubbles will form on a certain scale, and previous studies of Cahn-Hilliard dynamics seem to suggest the presence of one dominant length scale. However, the Cahn-Hilliard phase-separation mechanism contains a hyperdiffusion term and we show that, by stirring the mixture at a sufficiently large amplitude, we excite the diffusion and overwhelm the segregation to create a homogeneous liquid. At intermediate amplitudes we see regions of bubbles coexisting with regions of hyperdiffusive filaments. Thus, the problem possesses two dominant length scales, associated with the bubbles and filaments. For simplicity, we use use a chaotic flow that mimics turbulent stirring at large Prandtl number. We compare our results with the case of variable mobility, in which growth of bubble size is dominated by interfacial rather than bulk effects, and find qualitatively similar results.Comment: 20 pages, 27 figures. RevTeX

Socioeconomic inequalities in coronary heart disease risk in older age: contribution of established and novel coronary risk factors

Background:Evidence on socioeconomic inequalities in coronary heart disease (CHD) and their pathways in the elderly is limited. Little is also known about the contributions that novel coronary risk factors (particularly inflammatory/hemostatic markers) make to socioeconomic inequalities in CHD. Objectives:To examine the extent of socioeconomic inequalities in CHD in older age, and the contributions (relative and absolute) of established and novel coronary risk factors. Methods:A population-based cohort of 3761 British men aged 60–79 years was followed up for 6.5 years for CHD mortality and incidence (fatal and non-fatal). Social class was based on longest-held occupation recorded at 40–59 years. Results:There was a graded relationship between social class and CHD incidence. The hazard ratio for CHD incidence comparing social class V (unskilled workers) with social class I (professionals) was 2.70 [95% confidence interval (CI) 1.37–5.35; P-value for trend = 0.008]. This was reduced to 2.14 (95% CI 1.06–4.33; P-value for trend = 0.11) after adjustment for behavioral factors (cigarette smoking, physical activity, body mass index, and alcohol consumption), which explained 38% of the relative risk gradient (41% of absolute risk). Additional adjustment for inflammatory markers (C-reactive protein, interleukin-6, and von Willebrand factor) explained 55% of the relative risk gradient (59% of absolute risk). Blood pressure and lipids made little difference to these estimates; results were similar for CHD mortality. Conclusions:Socioeconomic inequalities in CHD persist in the elderly and are at least partly explained by behavioral risk factors; novel (inflammatory) coronary risk markers made some further contribution. Reducing inequalities in behavioral factors (especially cigarette smoking) could reduce these social inequalities by at least one-third

High Dietary Sodium Reduces Flow Mediated Dilation in Humans with Salt Sensitive & Salt Resistant BP

Please view abstract in the attached PDF file

Rotational properties of the O-type star population in the Tarantula region

The 30 Doradus (30\,Dor) region in the Large Magellanic Cloud (also known as the Tarantula Nebula) is the nearest massive starburst region, containing the richest sample of massive stars in the Local Group. It is the best possible laboratory to investigate aspects of the formation and evolution of massive stars. Here, we focus on rotation which is a key parameter in the evolution of these objects. We establish the projected rotational velocity, $v_{e}\sin i$, distribution of an unprecedented sample of 216 radial velocity constant ($\rm{\Delta RV\, \leq\, 20 \,km s^{-1}}$) O-type stars in 30\,Dor observed in the framework of the VLT-FLAMES Tarantula Survey (VFTS). The distribution of $v_{e}\sin i$ shows a two-component structure: a peak around 80 $\rm{km s^{-1}}$ and a high-velocity tail extending up to $\sim$600 $\rm{km s^{-1}}$. Around 75% of the sample has 0 $\leq\, v_{e}\sin i \leq$ 200 $\rm{km s^{-1}}$ with the other 25% distributed in the high-velocity tail. The presence of the low-velocity peak is consistent with that found in other studies of late-O and early-B stars. The high-velocity tail is compatible with expectations from binary interaction synthesis models and may be predominantly populated by post-binary interaction, spun-up, objects and mergers. This may have important implications for the nature of progenitors of long-duration gamma ray bursts.Comment: 4 pages, 1 figure. Conference proceedings article: Massive stars: from alpha to Omega, 10-14 June 2013, Rhodes, Greec

Rotational velocities of single and binary O-type stars in the Tarantula Nebula

Rotation is a key parameter in the evolution of massive stars, affecting their evolution, chemical yields, ionizing photon budget, and final fate. We determined the projected rotational velocity, $v_e\sin i$, of $\sim$330 O-type objects, i.e. $\sim$210 spectroscopic single stars and $\sim$110 primaries in binary systems, in the Tarantula nebula or 30 Doradus (30\,Dor) region. The observations were taken using VLT/FLAMES and constitute the largest homogeneous dataset of multi-epoch spectroscopy of O-type stars currently available. The most distinctive feature of the $v_e\sin i$ distributions of the presumed-single stars and primaries in 30 Dor is a low-velocity peak at around 100\,$\rm{km s^{-1}}$. Stellar winds are not expected to have spun-down the bulk of the stars significantly since their arrival on the main sequence and therefore the peak in the single star sample is likely to represent the outcome of the formation process. Whereas the spin distribution of presumed-single stars shows a well developed tail of stars rotating more rapidly than 300\,$\rm{km s^{-1}}$, the sample of primaries does not feature such a high-velocity tail. The tail of the presumed-single star distribution is attributed for the most part -- and could potentially be completely due -- to spun-up binary products that appear as single stars or that have merged. This would be consistent with the lack of such post-interaction products in the binary sample, that is expected to be dominated by pre-interaction systems. The peak in this distribution is broader and is shifted toward somewhat higher spin rates compared to the distribution of presumed-single stars. Systems displaying large radial velocity variations, typical for short period systems, appear mostly responsible for these differences.Comment: 6 pages, 3 figures, Proceedings IAU Symposium No. 307, 2014, 'New windows on massive stars: asteroseismology, interferometry, and spectropolarimetry