Die Rede von der Wiederkehr der städtischen Wohnungsfrage offenbart, dass dem Wohnen eine strukturelle Fundierung zugrunde liegt. Als Komponenten dieses Fundaments lassen sich die kapitalistische ...Kommodifizierung der Wohnung, das Festhalten am bürgerlichen Familienparadigma in der Wohnform und die Inszenierung individualistischer Lebensweise über das Wohnen ausmachen. Eine Auseinandersetzung mit Fragen ökologischer Nachhaltigkeit urbaner Räume im Zeichen der Klimakrise, sollte daher Gesellschaftsanalyse und Gesellschaftskritik in den Mittelpunkt der Debatte rücken. Stadtökologie sollte primär eine Frage der politischen Ökologie sein. Demzufolge müsste dem Wohnen als Teil der sozialen Infrastruktur schichtübergreifend Vorrang eingeräumt, kollektiven Wohnformen größere Spielräume der Umsetzung zugebilligt und Wohnbau regionalplanerisch organisiert werden.
We present a comprehensive chemical abundance analysis of five red giants and two horizontal branch (HB) stars towards the southern edge of the Galactic bulge, at (l, b) ~ (0°,−11°). Based on ...high-resolution spectroscopy obtained with the Magellan/MIKE spectrograph, we derived up to 23 chemical element abundances and identify a mixed bag of stars, representing various populations in the central regions of the Galaxy. Although cosmological simulations predict that the inner Galaxy was host to the first stars in the Universe, we see no chemical evidence of the ensuing massive supernova explosions: all of our targets exhibit halo-like, solar Sc/Fe ratios, which is in contrast to the low values predicted from Population III nucleosynthesis. One of the targets is a CEMP-s star at Fe/H = −2.52 dex, and another target is a moderately metal-poor (Fe/H = −1.53 dex) CH star with strong enrichment in s-process elements (e.g., Ba/Fe = 1.35). These individuals provide the first contenders of these classes of stars towards the bulge. Four of the carbon-normal stars exhibit abundance patterns reminiscent of halo star across a metallicity range spanning −2.0 to −2.6 dex, i.e., enhanced α-elements and solar Fe-peak and neutron-capture elements, and the remaining one is a regular metal-rich bulge giant. The position, distance, and radial velocity of one of the metal-poor HB stars coincides with simulations of the old trailing arm of the disrupted Sagittarius dwarf galaxy. While their highly uncertain proper motions prohibit a clear kinematic separation, the stars’ chemical abundances and distances suggest that these metal-poor candidates, albeit located towards the bulge, are not of the bulge, but rather inner halo stars on orbits that make them pass through the central regions. Thus, we caution similar claims of detections of metal-poor stars as true habitants of the bulge.
We present radial velocities and chemical abundances of O, Na, Mg, Al, Si, Ca, Cr, Fe, Co, Ni, and Cu for a sample of 156 red giant branch stars in two Galactic bulge fields centered near (l, b) = (+ ...5.25,-3.02) and (0,-12). The (+ 5.25,-3.02) field also includes observations of the bulge globular cluster NGC 6553. However, we only selected a subset of the original observations that included spectra with both high S/N and that did not show strong TiO absorption bands. This work extends previous analysis of this data set beyond Fe and the alpha -elements Mg, Si, Ca, and Ti. For most elements, the NGC 6553 stars exhibit abundance trends nearly identical to comparable metallicity bulge field stars. However, the star-to-star scatter and mean Na/Fe ratios appear higher in the cluster, perhaps indicating additional self-enrichment.
We present a chemical abundance study of the brightest confirmed member star of the ultra-faint dwarf galaxy Bootes II from Keck/HIRES high-resolution spectroscopy at moderate signal-to-noise ratios. ...At Fe/H = -2.93 + or - 0.03(stat.) + or -0.17(sys.), this star chemically resembles metal-poor halo field stars and the signatures of other faint dwarf spheroidal galaxies at the same metallicities in that it shows enhanced alpha /Fe ratios, Solar Fe-peak element abundances, and low upper limits on the neutron-capture element Ba. Moreover, this star shows no chemical peculiarities in any of the eight elements we were able to measure. This implies that the chemical outliers found in other systems remain outliers pertaining to the unusual enrichment histories of the respective environments, while Boo II appears to have experienced an enrichment history typical of its very low mass. We also re-calibrated previous measurements of the galaxy's metallicity from the calcium triplet (CaT) and find a much lower value than reported before. The resulting broad metallicity spread, in excess of one dex, the very metal-poor mean, and the chemical abundance patterns of the present star imply that Bootes II is a low-mass, old, metal-poor dwarf galaxy and not an overdensity associated with the Sagittarius Stream as has been previously suggested based on its sky position and kinematics. The low, mean CaT metallicity of -2.7 dex falls right on the luminosity-metallicity relation delineated over four orders of magnitude from the more luminous to the faintest galaxies. Thus Bootes II's chemical enrichment appears representative of the galaxy's original mass, while tidal stripping and other mass loss mechanisms were probably not significant as for other low-mass satellites.
Accurate forecasting of electricity prices can provide significant benefits to energy suppliers when allocating their assets and to energy consumers for defining an optimal portfolio. There are ...numerous methods that efficiently support the forecasting of time series, such as electricity prices, which have high volatility. However, the performance of these approaches varies depending on data sets and operational conditions. In this work, the concept of composite forecasting is presented and implemented in a retrospective study, in real industrial forecasting conditions to show the potential of forecast performance improvement and comparable high consistency of a forecast performance across different ‘Day Peak’ and ‘Day Base’ electricity price data sets for different seasons. As individual methods support vector regression, artificial neural networks and ridge regression are implemented. The forecast performances of these methods are evaluated and compared with their forecast combination using different error measures. The results show that composite forecasting processes with ‘inverse root mean squared error’ combination approach can generate, on average, a more accurate and robust forecast than using an individual methods or other combination schemas.
•A composite forecasting approach for a systematic search of consistent, high-performance forecast combining methods from different domains•Overall improvement of forecasting performance using composite forecasting approach against individual methods reached, up to 22 percent•The performance of combined forecasts using ‘Inverse of the Root Mean Squared Errors’ outperforms other combination schemas or separate methods
Aims.
The Chemical Evolution of
R
-process Elements in Stars (CERES) project aims to provide a homogeneous analysis of a sample of metal-poor stars (Fe/H < –1.5). We present the stellar parameters ...and the chemical abundances of elements up to Zr for a sample of 52 giant stars.
Methods.
We relied on a sample of high signal-to-noise UVES spectra. We determined stellar parameters from
Gaia
photometry and parallaxes. Chemical abundances were derived using spectrum synthesis and model atmospheres.
Results.
We determined chemical abundances of 26 species of 18 elements: Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, and Zr. For several stars, we were able to measure both neutral and ionised species, including Si, Sc, Mn, and Zr. We have roughly doubled the number of measurements of Cu for stars at Fe/H ≤ −2.5. The homogeneity of the sample made it possible to highlight the presence of two Zn-rich stars (Zn/Fe ∼ +0.7), one
r
-rich and the other
r
-poor. We report the existence of two branches in the Zn/Fe versus Ni/Fe plane and suggest that the high Zn/Fe branch is the result of hypernova nucleosynthesis. We discovered two stars with peculiar light neutron-capture abundance patterns: CES1237+1922 (also known as BS 16085-0050), which is ∼1 dex underabundant in Sr, Y, and Zr with respect to the other stars in the sample, and CES2250-4057 (also known as HE 2247-4113), which shows a ∼1 dex overabundance of Sr with respect to Y and Zr.
Conclusions.
The high quality of our dataset allowed us to measure hardly detectable ions. This can provide guidance in the development of line formation computations that take deviations from local thermodynamic equilibrium and hydrodynamical effects into account.
Metal-poor stars in the Galactic halo often show strong enhancements in carbon and/or neutron-capture elements. However, the Galactic bulge is notable for its paucity of these carbon-enhanced ...metal-poor (CEMP) and/or CH-stars, with only two such objects known to date. This begs the question whether the processes that produced their abundance distribution were governed by a comparable nucleosynthesis in similar stellar sites as for their more numerous counterparts in the halo. Recently, two contenders of these classes of stars were discovered in the bulge, at Fe/H = −1.5 and −2.5 dex, both of which show enhancements in C/Fe of 0.4 and 1.4 dex (respectively), Ba/Fe in excess of 1.3 dex, and also elevated nitrogen. The more metal-poor of the stars can be well matched by standard s-process nucleosynthesis in low-mass asymptotic giant branch (AGB) polluters. The other star shows an abnormally high Rb/Fe ratio. Here, we further investigate the origin of the abundance peculiarities in the Rb-rich star by new, detailed measurements of heavy element abundances and by comparing the chemical element ratios of 36 species to several models of neutron-capture nucleosynthesis. The i-process with intermediate neutron densities between those of the slow (s-) and rapid (r)-neutron-capture processes has been previously found to provide good matches of CEMP stars with enhancements in both r- and s-process elements (class CEMP-r/s), rather than invoking a superposition of yields from the respective individual processes. However, the peculiar bulge star is incompatible with a pure i-process from a single ingestion event. Instead, it can, statistically, be better reproduced by more convoluted models accounting for two proton ingestion events, or by an i-process component in combination with s-process nucleosynthesis in low-to-intermediate mass (2–3 M⊙) AGB stars, indicating multiple polluters. Finally, we discuss the impact of mixing during stellar evolution on the observed abundance peculiarities.
Abstract
Wide binaries, with separations between the two stars from a few au to more than several thousand au, are valuable objects for various research topics in Galactic astronomy. As the number of ...newly reported wide binaries continues to increase, studying the chemical abundances of their component stars becomes more important. We conducted high-resolution near-infrared (NIR) spectroscopy for six pairs of wide binary candidates using the Immersion Grating Infrared Spectrometer at the Gemini-South telescope. One pair was excluded from the sample due to a significant difference in radial velocity between its component stars, while the remaining five pairs exhibited homogeneous properties in 3D motion and chemical composition among the pair stars. The differences in Fe/H ranged from 0.00 to 0.07 dex for these wide binary pairs. The abundance differences between components are comparable to the previous results from optical spectroscopy for other samples. In addition, when combining our data with literature data, it appears that the variation of abundance differences increases in wide binaries with larger separations. However, SVO 2324 and SVO 3206 showed minimal differences in most elements despite their large separation, supporting the concept of multiple formation mechanisms depending on each wide binary. This study is the first approach to the chemical properties of wide binaries based on NIR spectroscopy. Our results further highlight that NIR spectroscopy is an effective tool for stellar chemical studies based on equivalent measurements of chemical abundances from the two stars in each wide binary system.
To date, there are few studies and no systematic reviews focusing specifically on groin hernia in women. Most of the existing knowledge comes from registry data.
This present review now reports on ...such findings as are available on groin hernia in women.
A systematic search of the available literature was performed in September 2018 using Medline, PubMed, Google Scholar, and the Cochrane Library. For the present analysis 80 publications were identified.
The lifetime risk of developing a groin hernia in women is 3-5.8%. The proportion of women in the overall collective of operated groin hernias is 8.0-11.5%. In women, the proportion of femoral hernias is 16.7-37%. Risk factors for development of a groin hernia in women of high age and with a positive family history. A groin hernia during pregnancy should not be operated on. The rate of emergency procedures in women, at 14.5-17.0%, is 3 to 4-fold higher than in men and at 40.6% is even higher for femoral hernia. Therefore, watchful waiting is not indicated in women. During surgical repair of groin hernia in females the presence of a femoral hernia should always be excluded and if detected should be repaired using a laparo-endoscopic or open preperitoneal mesh technique. A higher rate of chronic postoperative inguinal pain must be expected in females.
Special characteristics must be taken into account for repair of groin hernia in women.
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