Regime‐dependent statistical post‐processing of ensemble forecasts

This is the final version. Available on open access from Wiley via the DOI in this recordA number of realisations of one or more numerical weather prediction (NWP) models, initialised at a variety of initial conditions, compose an ensemble forecast. These forecasts exhibit systematic errors and biases that can be corrected by statistical post‐processing. Post‐processing yields calibrated forecasts by analysing the statistical relationship between historical forecasts and their corresponding observations. This paper aims to extend post‐processing methodology to incorporate atmospheric circulation. The circulation, or flow, is largely responsible for the weather that we experience and it is hypothesised here that relationships between the NWP model and the atmosphere depend upon the prevailing flow. Numerous studies have focussed on the tendency of this flow to reduce to a set of recognisable arrangements, known as regimes, which recur and persist at fixed geographical locations. This dynamical phenomenon allows the circulation to be categorised into a small number of regime states. In a highly idealised model of the atmosphere, the Lorenz ’96 system, ensemble forecasts are subjected to well‐known post‐processing techniques conditional on the system's underlying regime. Two different variables, one of the state variables and one related to the energy of the system, are forecasted and considerable improvements in forecast skill upon standard post‐processing are seen when the distribution of the predictand varies depending on the regime. Advantages of this approach and its inherent challenges are discussed, along with potential extensions for operational forecasters.Natural Environment Research Council (NERC

Dynamical evolution of titanium, strontium, and yttrium spots on the surface of the HgMn star HD 11753

Aims. We gathered about 100 high-resolution spectra of three typical HgMn (mercury-manganese) stars, HD 11753, HD 53244, and HD 221507, to search for slowly pulsating B-like pulsations and surface inhomogeneous distribution of various chemical elements. Methods. Classical frequency analysis methods were used to detect line profile variability and to determine the variation period. Doppler imaging reconstruction was performed to obtain abundance maps of chemical elements on the stellar surface. Results. For HD 11753, which is the star with the most pronounced variability, distinct spectral line profile changes were detected for Ti, Sr, Y, Zr, and Hg, whereas for HD 53244 and HD 221507 the most variable line profiles belong to the elements Hg and Y, respectively. We derived rotation periods for all three stars from the variations of radial velocities and equivalent widths of spectral lines belonging to inhomogeneously distributed elements: P_rot (HD 11753)=9.54 d, P_rot (HD 53244)=6.16 d, and P_rot (HD 221507)=1.93 d. For HD 11753 the Doppler imaging technique was applied to derive the distribution of the most variable elements Ti, Sr, and Y using two datasets separated by ~65 days. Results of Doppler imaging reconstruction revealed noticeable changes in the surface distributions of TiII, SrII, and YII between the datasets, indicating the hitherto not well understood physical processes in stars with radiative envelopes that cause a rather fast dynamical chemical spot evolution.Comment: Accepted for publication in Astronomy and Astrophysics, 6 pages, 9 figures, 2 tables

Spectroscopic Survey of {\gamma} Doradus Stars I. Comprehensive atmospheric parameters and abundance analysis of {\gamma} Doradus stars

We present a spectroscopic survey of known and candidate $\gamma$\,Doradus stars. The high-resolution, high signal-to-noise spectra of 52 objects were collected by five different spectrographs. The spectral classification, atmospheric parameters (\teff, $\log g$, $\xi$), $v\sin i$ and chemical composition of the stars were derived. The stellar spectral and luminosity classes were found between G0-A7 and IV-V, respectively. The initial values for \teff\ and \logg\ were determined from the photometric indices and spectral energy distribution. Those parameters were improved by the analysis of hydrogen lines. The final values of \teff, \logg\ and $\xi$ were derived from the iron lines analysis. The \teff\ values were found between 6000\,K and 7900\,K, while \logg\,values range from 3.8 to 4.5\,dex. Chemical abundances and $v\sin i$ values were derived by the spectrum synthesis method. The $v\sin i$ values were found between 5 and 240\,km\,s$^{-1}$. The chemical abundance pattern of $\gamma$\,Doradus stars were compared with the pattern of non-pulsating stars. It turned out that there is no significant difference in abundance patterns between these two groups. Additionally, the relations between the atmospheric parameters and the pulsation quantities were checked. A strong correlation between the $v\sin i$ and the pulsation periods of $\gamma$\,Doradus variables was obtained. The accurate positions of the analysed stars in the H-R diagram have been shown. Most of our objects are located inside or close to the blue edge of the theoretical instability strip of $\gamma$\,Doradus.Comment: 18 pages, 13 figure

Domesticating Fears and Fantasies of ‘the East’: integrating the Ottoman legacy within European heritage

'Europe' has no fixed geographical, historical, religious or cultural boundaries. Claims for the existence of European civilization as a discrete construct are continually made yet dissolve on close scrutiny. Here, we examine these claims at one of the grandest points of existential crisis and belonging for Europe, the relationship with the 'Other within': Turkey, the Balkans and Ottoman heritage in Europe. Through a hybrid semiotic and Foucauldian analysis of catalogues of eight high-profile exhibitions in the United Kingdom, Turkey, Belgium and Portugal we argue that an unsettled discursive struggle is at play, in which one 'Europe' articulates 'reconciliation' of profound civilizational difference while another, Ottoman, 'Europe' stakes a claim of right as an intrinsic component of what it means to be European in a contemporary context. We attempt to trace the role of museum marketing in the perennial accommodation/exclusion of the Ottoman Empire as an intrinsic component in the diversity of Europe’s cultural heritage

MOST light-curve analysis of the gamma Dor pulsator HR 8799, showing resonances and amplitude variations

Context: The central star of the HR 8799 system is a gamma Doradus-type pulsator. The system harbours four planetary-mass companions detected by direct imaging, and is a good solar system analogue. The masses of the companions are not known accurately, because the estimation depends strongly on the age of the system, which is also not known with sufficient accuracy. Asteroseismic studies of the star might help to better constrain the age of HR 8799. We organized an extensive photometric and multi-site spectroscopic observing campaign for studying the pulsations of the central star. Aims: The aim of the present study is to investigate the pulsation properties of HR 8799 in detail via the ultra-precise 47-d-long nearly continuous photometry obtained with the MOST space telescope, and to find as many independent pulsation modes as possible, which is the prerequisite of an asteroseismic age determination. Methods: We carried out Fourier analysis of the wide-band photometric time series. Results: We find that resonance and sudden amplitude changes characterize the pulsation of HR 8799. The dominant frequency is always at f1 = 1.978 c/d. Many multiples of one ninth of the dominant frequency appear in the Fourier spectrum of the MOST data: n/9 f1, where n={1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 13, 14, 17, 18}. Our analysis also reveals that many of these peaks show strong amplitude decrease and phase variations even on the 47-d time-scale. The dependencies between the pulsation frequencies of HR 8799 make the planned subsequent asteroseismic analysis rather difficult. We point out some resemblance between the light curve of HR 8799 and the modulated pulsation light curves of Blazhko RR Lyrae stars.Comment: Accepted for publication in Astronomy and Astrophysics. 8 pages, 4 figure

Impact of the policy environment on substance use among sexual minority women

Background: Sexual minority women (SMW) are at greater risk for heavy episodic drinking, frequent marijuana use, and tobacco use than heterosexual women. Because past research has suggested the political and social environment may influence disparities in substance use by sexual orientation, this study examined associations of the U.S. state-level policy environment on substance use by SMW. Methods: A total of 732 SMW participants were recruited from two national online panels: a general population panel (n = 333) and a sexual minority-specific panel (n = 399). Past year substance use was defined by number of days of heavy episodic drinking (HED; 4+ drinks in a day), weekly tobacco use (once a week or more vs. less or none), and weekly marijuana use (once a week or more vs. less or none). Comprehensive state policy protection was defined by enactment of five policies protecting rights of sexual minorities. Regression models compared substance use outcomes for SMW living in states with comprehensive policy protections to SMW living in states with fewer or no protections. Models also assessed the impact of state policies related to alcohol (state monopoly on alcohol wholesale or retail sales), tobacco (state enactment of comprehensive smoke-free workplace laws) and marijuana (legalization of purchase, possession, or consumption of marijuana for recreational use). Results: Comprehensive policy protections were associated with fewer HED days. Recreational marijuana legalization was associated with higher odds of weekly use. Conclusions: Findings underscore the importance of policy protections for sexual minorities in reducing substance use, particularly HED, among SMW

The endothelial mineralocorticoid receptor regulates vasoconstrictor tone and blood pressure

Pathophysiological aldosterone (aldo)/mineralocorticoid receptor (MR) signaling has significant effects on the cardiovascular system, resulting in hypertension and cardiovascular remodeling; however, the specific contribution of the vascular MR to blood pressure regulation remains to be established. To address this question, we generated a mouse model with conditional overexpression of the MR in endothelial cells (MR-EC). In basal conditions, MR-EC mice developed moderate hypertension that could be reversed by canrenoate, a pharmacological MR antagonist. MR-EC mice presented increased contractile response of resistance arteries to vasoconstrictors (phenylephrine, thromboxane A(2) analog, angiotensin II, and endothelin 1) in the absence of vascular morphological alterations. The acute blood pressure response to angiotensin II or endothelin 1 infusion was increased in MR-EC mice compared with that in littermate controls. These observations demonstrate that enhanced MR activation in the endothelium generates an increase in blood pressure, independent of stimulation of renal tubular Na(+) transport by aldo/MR or direct activation of smooth muscle MR and establish one mechanism by which endothelial MR activation per se may contribute to impaired vascular reactivity

Gravity modes in rapidly rotating stars. Limits of perturbative methods

CoRoT and Kepler missions are now providing high-quality asteroseismic data for a large number of stars. Among intermediate-mass and massive stars, fast rotators are common objects. Taking the rotation effects into account is needed to correctly understand, identify, and interpret the observed oscillation frequencies of these stars. A classical approach is to consider the rotation as a perturbation. In this paper, we focus on gravity modes, such as those occurring in gamma Doradus, slowly pulsating B (SPB), or Be stars. We aim to define the suitability of perturbative methods. With the two-dimensional oscillation program (TOP), we performed complete computations of gravity modes -including the Coriolis force, the centrifugal distortion, and compressible effects- in 2-D distorted polytropic models of stars. We started with the modes l=1, n=1-14, and l=2-3, n=1-5,16-20 of a nonrotating star, and followed these modes by increasing the rotation rate up to 70% of the break-up rotation rate. We then derived perturbative coefficients and determined the domains of validity of the perturbative methods. Second-order perturbative methods are suited to computing low-order, low-degree mode frequencies up to rotation speeds ~100 km/s for typical gamma Dor stars or ~150 km/s for B stars. The domains of validity can be extended by a few tens of km/s thanks to the third-order terms. For higher order modes, the domains of validity are noticeably reduced. Moreover, perturbative methods are inefficient for modes with frequencies lower than the Coriolis frequency 2Omega. We interpret this failure as a consequence of a modification in the shape of the resonant cavity that is not taken into account in the perturbative approach.Comment: 8 pages, 6 figures, Astronomy & Astrophysics (in press

A comprehensive study of the open cluster NGC 6866

We present CCD $UBVRI$ photometry of the field of the open cluster NGC 6866. Structural parameters of the cluster are determined utilizing the stellar density profile of the stars in the field. We calculate the probabilities of the stars being a physical member of the cluster using their astrometric data and perform further analyses using only the most probable members. The reddening and metallicity of the cluster were determined by independent methods. The LAMOST spectra and the ultraviolet excess of the F and G type main-sequence stars in the cluster indicate that the metallicity of the cluster is about the solar value. We estimated the reddening $E(B-V)=0.074 \pm 0.050$ mag using the $U-B$ vs $B-V$ two-colour diagram. The distance modula, the distance and the age of NGC 6866 were derived as $\mu = 10.60 \pm 0.10$ mag, $d=1189 \pm 75$ pc and $t = 813 \pm 50$ Myr, respectively, by fitting colour-magnitude diagrams of the cluster with the PARSEC isochrones. The Galactic orbit of NGC 6866 indicates that the cluster is orbiting in a slightly eccentric orbit with $e=0.12$. The mass function slope $x=1.35 \pm 0.08$ was derived by using the most probable members of the cluster.Comment: 14 pages, including 16 figures and 7 tables, accepted for publication in MNRAS. Table 4 in the manuscript will be published electronicall

Comparing substance use outcomes by sexual identity among women: Differences using propensity score methods

Background: Differences in alcohol, tobacco, and other drug (ATOD) use by sexual identity vary across samples of women recruited using different sampling methods. We used propensity score (PS) weighting methods to address two methodological questions: (1) Do disparities between sexual minority women (SMW) and heterosexual women persist when differences in risk and protective factors are similarly distributed between groups, and (2) Does accounting for SMW-specific resiliency factors impact differences between non-probability samples of SMW? Methods: Four samples included SMW from a longitudinal study with a nonprobability sample (n = 373), a national general population panel sample (n = 373), and a national LGBTQ-specific panel sample (n = 311), as well as a national probability sample of heterosexual women (n = 446). Between-groups analyses using double-robust PS weighted models estimated differences in ATOD use under hypothetical conditions in which samples have similar risk and protective factors. Results: After PS weighting, imbalance in confounders between SMW and heterosexual samples was substantially reduced, but not eliminated. In double-robust PS weighted models, SMW samples consistently had significantly greater odds of drug use than heterosexuals, with odds from 8.8 to 5.6 times greater for frequent marijuana use and 4.8–3.2 greater for other drug use. Few differences between SMW samples in ATOD outcomes or other variables remained after PS weighting. Conclusion: Relative to heterosexual women, disparities in marijuana and other drug use among SMW are evident regardless of sampling strategy. The results provide some reassurance about the validity of large nonprobability samples, which remain an important recruitment strategy in research with SMW