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We introduce a new generation of PARSEC-COLIBRI stellar isochrones that include a detailed treatment of the thermally-pulsing asymptotic giant branch (TP-AGB) phase, and covering a wide range of initial metallicities (0.0001

We present the results of our survey of 1612 MHz circumstellar OH maser emission from asymptotic giant branch (AGB) stars and red supergiants (RSGs) in the Large Magellanic Cloud. We have discovered four new circumstellar maser sources in the LMC, and increased the number of reliable wind speeds from IR stars in the LMC from 5 to 13. Using our new wind speeds, as well as those from Galactic sources, we have derived an updated relation for dust driven winds: $v_{exp} \propto Z L^{0.4}$. We compare the sub-solar metallicity LMC OH/IR stars with carefully selected samples of more metal-rich OH/IR stars, also at known distances, in the Galactic Centre and Galactic Bulge. For 8 of the Bulge stars we derive pulsation periods for the first time, using near-IR photometry from the VVV survey. We have modeled our LMC OH/IR stars and developed an empirical method of deriving gas-to-dust ratios and mass loss rates by scaling the models to the results from maser profiles. We have done this also for samples in the Galactic Centre and Bulge and derived a new mass loss prescription that includes luminosity, pulsation period, and gas-to-dust ratio $\dot{M} = 1.06^{+3.5}_{-0.8} \rm{ \cdot }10^{-5}\,(L/10^4\,\rm{L}_\odot)^{0.9\pm0.1}(P/500\,\rm{d})^{0.75\pm0.3} (r_{gd}/200)^{-0.03\pm0.07}\,\rm{M_{\odot}}\, yr^{-1}$. The tightest correlation is found between mass loss rate and luminosity. We find that the gas-to-dust ratio has little effect on the mass loss of oxygen-rich AGB stars and RSGs within the Galaxy and the LMC. This suggests that mass loss of oxygen-rich AGB stars and RSGs is (nearly) independent of metallicity between a half and twice solar., Comment: 33 pages, 29 figures, accepted for publication in MNRAS

We present the results of hydrodynamic simulations of the interaction between a 10 Jupiter mass planet and a red or asymptotic giant branch stars, both with a zero-age main sequence mass of 3.5 $M_\odot$. Dynamic in-spiral timescales are of the order of few years and a few decades for the red and asymptotic giant branch stars, respectively. The planets will eventually be destroyed at a separation from the core of the giants smaller than the resolution of our simulations, either through evaporation or tidal disruption. As the planets in-spiral, the giant stars' envelopes are somewhat puffed up. Based on relatively long timescales and even considering the fact that further in-spiral should take place before the planets are destroyed, we predict that the merger would be difficult to observe, with only a relatively small, slow brightening. Very little mass is unbound in the process. These conclusions may change if the planet's orbit enhances the star's main pulsation modes. Based on the angular momentum transfer, we also suspect that this star-planet interaction may be unable to lead to large scale outflows via the rotation-mediated dynamo effect of Nordhaus and Blackman. Detectable pollution from the destroyed planets would only result for the lightest, lowest metallicity stars. We furthermore find that in both simulations the planets move through the outer stellar envelopes at Mach-3 to Mach-5, reaching Mach-1 towards the end of the simulations. The gravitational drag force decreases and the in-spiral slows down at the sonic transition, as predicted analytically., Comment: Accepted for publication in MNRAS

"Sustainability" is a key idea on college campuses in the United States and the rest of the Western world. To the unsuspecting, sustainability is just a new name for environmentalism. This report is the first in-depth critical study of the sustainability movement in higher education. The focus of this study is on how the sustainability movement has, according to these authors, distorted higher education, the harm it has done to college curricula, and the limits it has imposed on the freedom of students to inquire and to make their own decisions. The report explains how the sustainability movement came to prominence and how it is organized. After presenting the findings, the report offers recommendations and concludes that the sustainability movement has become a major force in American life that has largely escaped serious critical scrutiny. The goal of this report is to change that by examining for the first time the movement's ideological, economic, and practical effects on institutions of higher education. The following are appended: (1) Living with Climate Orthodoxy on Campus: One Professor's Take; (2) Divesting Reason: A Student's Perspective; (3) Environmental Lysenkoism: Reflections from a Scientist; and (4) A Transnational, "Precautionary" Movement: Thoughts from an International Trade Lawyer. An index is also included.

Assigning a summer reading to entering freshmen is a growing trend at hundreds of American colleges and universities. Colleges typically pick one book and ask students to read it outside their courses. Many invite the author to help kick off the year by speaking on campus at convocation. Most colleges see the key purpose of a common reading program as an opportunity to build community on campus. Many also declare that common reading is important because it sets academic expectations, begins conversations, inspires social activism, and encourages critical thinking. This years' annual "Beach Books" reports is the most comprehensive and the only one to categorize the books according to their main subjects and track trends in genres, publication dates, and additional themes. The study for the academic year 2013-2014 covers 341 colleges and universities and the 231 books they assigned. The authors present the results of their study in terms of findings, facts, and gaps. Their findings: (1) Common reading programs are becoming more popular; (2) The list of readings continues to be dominated by recent, trendy, and intellectually unchallenging books; (3) The assigned books frequently emphasize progressive political themes, and the top subject category is multiculturalism; (4) Colleges increasingly see their common reading as exercises in community-building more than student preparation for academic life; and (5) A common reading "industry" is emerging, with publishers, authors, and colleges seeking to advance a particular kind of book. The facts: (1) Author speaking: Of the 341 colleges in our study, 231 (68 percent) brought the author to speak on campus. Having the author speak is seen as a priority for common reading programs; (2) Rationales: 77 percent of colleges said that the purpose of their common reading programs was to foster "community," or create "common" or "shared" experiences among those on and near the campus; (3) Recent: More than half of common reading assignments (51 percent) were published between 2010 and 2013, and only five books were from before 1900; (4) Non-fiction: 72 percent of assignments were memoirs, biographies, essays, and other non-fiction; and (5) Turnover: 82 percent of this year's titles are different from last year's. Some books that were popular a few years ago are now waning or have disappeared. Many new books, some published as recently as the year in which they were assigned, are being introduced. The gaps: (1) Classics: Only four colleges assigned works that could be considered classics. Those were Melville's short story "Bartleby, the Scrivener" (LeMoyne College), a compilation of Shakespeare's works (Indiana University, South Bend), the book of Job from the Bible (St. Michael's College), and Edgar Allen Poe's Great Tales and Poems (University of Wisconsin, Parkside). Other than these exceptions, the hundreds of common reading programs across the country ignored books of lasting merit. Dickens, Dostoevsky, Austen, and Hemingway were not to be found. There was no trace of Twain, Tolstoy, Brontë, Wilde, Hawthorne, Douglass, or Steinbeck. No "To Kill a Mockingbird," "The Great Gatsby," "The Count of Monte Cristo," or even "Catcher in the Rye"; (2) Fiction: Only 28 percent of common reading assignments were fictional. While fiction isn't going away in the larger scheme of contemporary reading, colleges are predisposed against it because they want to show students socially-engaged authors who are active in the real world; (3) Modern literature: Even in confining themselves to living authors, colleges neglect some of the best ones, such as Marilynne Robinson, Thomas Pynchon, Wendell Berry, Donna Tart, Tom Wolfe, and Don DeLillo; (4) History: Other than a "media package" on the civil rights movement assigned by the University of Alabama, Birmingham, no colleges assigned any works of history; and (5) Diversity: There is essentially a common reading genre--inspiring stories, apocalyptic visions, self-assigned projects, identity crises, advice manuals, and curious trends in human behavior--this is the stuff of common reading, and rarely do colleges deviate from these norms. The most-assigned book, for the third year in a row, is "The Immortal Life of Henrietta Lacks." While there were fewer classic books assigned in 2013-2014 than the year before, there were more "honorable mentions," books that treat academic subjects (i.e. physics, economics, poetry, philosophy) with depth and detail, as well as others that take an uncharacteristically hopeful view of immigration, hard work, or life's challenges. The authors note that college administrators and outside observers have been asking questions as to the value of campus common reading programs and students also have doubts about the value of common reading programs. While they recognize the potential of the programs to build intellectual community, students are often disappointed to be given an unchallenging book, or a book ostensibly chosen to fulfill a diversity obligation. The study offers 12 recommendations to colleges for choosing better books and making the most of the common reading experience. Appended are: (1) Key and Totals; (2) Books Chosen as Common Reading 2013-2014: Full List by Institution Name; (3) Titles by Subject Category; (4) By Institution Type; (5) Beach Books in Practice: "The View From My Island"; (6) Common Reading Programs: "Beginning The Process"; (7) Common Reading Books and a Measure of Student Reaction to Them; (8) "Caught with Gay Books: South Carolina Punishes Colleges for Freshman Reading Choices"; and (9) "Williams Reads' Book Selection was a Flop." [For the previous edition, "Beach Books: 2011-2012. What Do Colleges and Universities Want Students to Read outside Class?," see ED540342.]

We have carried out a search for optically visible post-Asymptotic Giant Branch (post-AGB) stars in the Large Magellanic Cloud (LMC). First, we selected candidates with a mid-IR excess and then obtained their optical spectra. We disentangled contaminants with unique spectra such as M-stars, C-stars, planetary nebulae, quasi-stellar objects and background galaxies. Subsequently, we performed a detailed spectroscopic analysis of the remaining candidates to estimate their stellar parameters such as effective temperature, surface gravity (log g), metallicity ([Fe/H]), reddening and their luminosities. This resulted in a sample of 35 likely post-AGB candidates with late-G to late-A spectral types, low log g, and [Fe/H] < -0.5. Furthermore, our study confirmed the existence of the dusty post-Red Giant Branch (post-RGB) stars, discovered previously in our SMC survey, by revealing 119 such objects in the LMC. These objects have mid-IR excesses and stellar parameters (Teff, log g, [Fe/H]) similar to those of post-AGB stars except that their luminosities (< 2500 Lsun), and hence masses and radii, are lower. These post-RGB stars are likely to be products of binary interaction on the RGB. The post-AGB and post-RGB objects show SED properties similar to the Galactic post-AGB stars, where some have a surrounding circumstellar shell, while some others have a surrounding stable disc similar to the Galactic post-AGB binaries. This study also resulted in a new sample of 162 young stellar objects, identified based on a robust log g criterion. Other interesting outcomes include objects with an UV continuum and an emission line spectrum; luminous supergiants; hot main-sequence stars; and 15 B[e] star candidates, 12 of which are newly discovered in this study., Comment: Published in MNRAS 64 pages, 14 figures, 8 tables, 3 appendices. arXiv admin note: text overlap with arXiv:1402.5954

Optimising queries in real-world situations under imperfect conditions is still a problem that has not been fully solved. We consider finding the optimal order in which to execute a given set of selection operators under partial ignorance of their selectivities. The selectivities are modelled as intervals rather than exact values and we apply a concept from decision theory, the minimisation of the maximum regret, as a measure of optimality. We show that the associated decision problem is NP-hard, which renders a brute-force approach to solving it impractical. Nevertheless, by investigating properties of the problem and identifying special cases which can be solved in polynomial time, we gain insight that we use to develop a novel heuristic for solving the general problem. We also evaluate minmax regret query optimisation experimentally, showing that it outperforms a currently employed strategy of optimisers that uses mean values for uncertain parameters.

We discuss properties of oscillatory convective modes in low-mass red giants, and compare them with observed properties of the long secondary periods (LSPs) of semi-regular red giant variables. Oscillatory convective modes are very nonadiabatic g$^{-}$ modes and they are present in luminous stars, such as red giants with $\log L/{\rm L}_\odot \ga 3$. Finite amplitudes for these modes are confined to the outermost nonadiabatic layers, where the radiative energy flux is more important than the convective energy flux. The periods of oscillatory convection modes increase with luminosity, and the growth times are comparable to the oscillation periods. The LSPs of red giants in the Large Magellanic Cloud (LMC) are observed to lie on a distinct period-luminosity sequence called sequence D. This sequence D period-luminosity relation is roughly consistent with the predictions for dipole oscillatory convective modes in AGB models if we adopt a mixing length of 1.2 pressure scale height ($\alpha = 1.2$). However, the effective temperature of the red-giant sequence of the LMC is consistent to models with $\alpha=1.9$, which predict periods too short by a factor of two., Comment: 7 pages, 6 figures, accepted for publication in MNRAS

Aims. We study the effects of moderate deviations from solar abundances upon the atmospheric structure and colours of typical Mira variables. Methods. We present two model series of dynamical opacity-sampling models of Mira variables which have (1) 1 solar metallicity 3 and (2) "mild" S-type C/O abundance ratio ([C/O]=0.9) with typical Zr enhancement (solar +1.0). These series are compared to a previously studied solar-abundance series which has similar fundamental parameters (mass, luminosity, period, radius) that are close to those of o Cet. Results. Both series show noticeable effects of abundance upon stratifications and infrared colours but cycle-to-cycle differences mask these effects at most pulsation phases, with the exception of a narrow-water-filter colour near minimum phase., Comment: 4 pages, 3 figures, accepted for A&A

"The Vanishing West" traces the decline and near extinction of the Western Civilization history survey course in America's top colleges and universities from 1964 to 2010. This course, covering classical antiquity to the present, was once part of the undergraduate curriculum's intellectual bedrock, not only because it was often a graduation requirement, but because it gave narrative coherence to everything else the university taught. In studying the rise of the West, students came to grips with how the arts and sciences encountered in other classes had been shaped. And because Western Civilization had "gone global," they also learned what made the world outside campus the place it had become. They usually finished with at least a partial recognition of their civilization as a grand monument to human achievement and something with which to identify. In 1964, the Western Civilization survey course in various guises, along with related courses such as Great Books surveys, were to be found at all the colleges and universities the authors surveyed. By 2010, the course had disappeared entirely as a requirement at these institutions and was available in some less emphasized form at less than a third of them. Reviving the Western Civilization survey in the form that served earlier generations probably is neither feasible nor desirable. Historical scholarship, including knowledge of the West's interactions with other civilizations and cultures, has progressed. An up-to-date survey would have to take account of this new scholarship. But a historical overview of the Western ascent toward freedom, scientific and technology mastery, and world power, is no less essential to the current generation than it was to those past. "The Vanishing West" invites a new dialogue on how best to resume the work of teaching a rounded overview of civilization to young men and women on whom the responsibility will fall to maintain and improve it. The authors offer twenty-three recommendations aimed at better studying the problem, rebuilding the curriculum, and repairing the graduate education pipeline, so that the history profession will again begin to prepare faculty capable of, and interested in, teaching about the broad course of Western history. Appended are: (1) Syllabus of a Western Civilization Course Offered in Spring 2011; and (2) Tables. (Contains 4 tables, 4 figures and 20 footnotes.)

Independent learning is a buzz word that is often used in connection with computer technologies applied to the area of foreign language instruction. This chapter takes a critical look at some of the stereotypes that exist with regard to computer-assisted language learning (CALL) as a money saver and an easy way to create an "independent" learning environment. It will also look at what currently available tutorial CALL is able to offer and at how to assess users' independence in this environment. The chapter establishes a working definition of learner independence and shows that tutorial CALL is currently only able to help learners become independent to a limited extent. A paradigm shift in language teaching aimed at promoting learner independence necessitates a shift in the design of dedicated CALL software. As an example of how natural language processing (NLP) technologies can be used to promote independent language learning at an advanced stage, the paper briefly presents QuickAssist, an application which enables learners to work with a German text of their choice using a set of NLP tools, and reports on some findings of a user study. [For the complete volume, "Second Language Teaching and Learning with Technology: Views of Emergent Researchers," see ED574599.]

We report on the results of a long time photometric monitoring of the two metal poor Galactic globular clusters M22 and IC4499 searching for long period variables (LPVs) on the upper giant branch. We detected 22 new LPVs in the field of M22 and confirmed the variability of six known variables. Periods could be determined for 16 of them. In the field of IC4499 we detected and characterized 2 new LPVs. Cluster membership is evaluated for all the variables based on photometry and literature data, and the location of the stars in logP-K-diagram is discussed. Our findings give further support to the presence of LPVs at metallicities as low as [Fe/H]=-1.7. The luminosity range where LPVs are found in metal poor clusters is lower than in more metal rich clusters., Comment: 10 pages, 5 figures; accepted for publication in PASA

Stellar photospheres of post-asymptotic giant branch stars bear witness to the internal chemical enrichment processes, integrated over their entire stellar evolution. Here we study post-AGB stars in the Large Magellanic Cloud (LMC). With their known distances, these rare objects are ideal tracers of AGB nucleosynthesis and dredge-up phenomena. We used the UVES spectrograph mounted on the Very Large Telescope (VLT) at the European Southern Observatory (ESO), to obtain high-resolution spectra with high signal-to-noise (S/N) of a sample of four post-AGB stars. The objects display a spectral energy distribution (SED) that indicates the presence of circumstellar dust. All objects are carbon-rich, and strongly enhanced in s-process elements. We deduced abundances of heavy s-process elements for all stars in the sample, and even found an indication of the presence of Hg in the spectrum of one object. The metallicity of all stars except J053253.51-695915.1 is considerably lower than the average value that is observed for the LMC. The derived luminosities show that we witness the late evolution of low-mass stars with initial masses close to 1 solar mass. An exception is J053253.51-695915.1 and we argue that this object is likely a binary. We confirmed the correlation between the efficiency of the third-dredge up and the neutron exposure that is detected in Galactic post-AGB stars. The non-existence of a correlation between metallicity and neutron irradiation is also confirmed and expanded to smaller metallicities. We confirm the status of 21-micron stars as post-Carbon stars. Current theoretical AGB models overestimate the observed C/O ratios and fail to reproduce the variety of s-process abundance patterns that is observed in otherwise very similar objects. Similar results have recently been found for a post-AGB star in the Small Magellanic Cloud (SMC)., Comment: 15 pages, 11 figures, accepted for publication in A&A

The stellar initial mass function (IMF) plays a crucial role in determining the number of surviving stars in galaxies, the chemical composition of the interstellar medium, and the distribution of light in galaxies. A key unsolved question is whether the IMF is universal in time and space. Here we use state-of-the-art results of stellar evolution to show that the IMF of our Galaxy made a transition from an IMF dominated by massive stars to the present-day IMF at an early phase of the Galaxy formation. Updated results from stellar evolution in a wide range of metallicities have been implemented in a binary population synthesis code, and compared with the observations of carbon-enhanced metal-poor (CEMP) stars in our Galaxy. We find that applying the present-day IMF to Galactic halo stars causes serious contradictions with four observable quantities connected with the evolution of AGB stars. Furthermore, a comparison between our calculations and the observations of CEMP stars may help us to constrain the transition metallicity for the IMF which we tentatively set at [Fe/H] = -2. A novelty of the current study is the inclusion of mass loss suppression in intermediate-mass AGB stars at low-metallicity. This significantly reduces the overproduction of nitrogen-enhanced stars that was a major problem in using the high-mass star dominated IMF in previous studies. Our results also demonstrate that the use of the present day IMF for all time in chemical evolution models results in the overproduction of Type I.5 supernovae. More data on stellar abundances will help to understand how the IMF has changed and what caused such a transition., Comment: 8 pages, 2 figures, accepted by MNRAS Letter

By virtue of their spectral types, favourable bolometric corrections as well as their constrained distances, post-AGB stars in external galaxies offer unprecedented tests to AGB nucleosynthesis and dredge-up predictions. We focus here on one object J004441.04-732136.4, which is the only known 21 micrometer source of the SMC. Spectral abundance results reveal J004441.04-732136.4 to be one of the most s-process enriched objects found up to date, while the photospheric C/O ratio of 1.9 +- 0.7, shows the star is only modestly C-rich. J004441.04-732136.4 also displays a low [Fe/H] = -1.34 +- 0.32, which is significantly lower than the mean metallicity of the SMC. From the SED, a luminosity of 7600 +- 200 solar luminosities is found, together with E(B-V) = 0.64 +- 0.02. According to evolutionary post-AGB tracks, the initial mass should be approximately 1.3 solar masses. The photometric variability shows a clear period of 97.6 +- 0.3 days. The detected C/O as well as the high s-process overabundances (e.g. [Y/Fe] = 2.15, [La/Fe] = 2.84) are hard to reconcile with the predictions. The chemical models also predict a high Pb abundance, which is not compatible with the detected spectrum, and a very high 12C/13C, which is not yet constrained by observations. The predictions are only marginally dependent on the evolution codes used. We show that our theoretical predictions match the s-process distribution, but fail in reproducing the detected high overabundances and predict a high Pb abundance which is not detected. Additionally, there remain serious problems in explaining the observed pulsational properties of this source., Comment: 15 pages, 18 figures, accepted for publication in A&A Main Journal

We obtained high-resolution near-IR spectra of 45 AGB stars located in the Galactic bulge. The aim of the project is to determine key elemental abundances in these stars to help constrain the formation history of the bulge. A further aim is to link the photospheric abundances to the dust species found in the winds of the stars. Here we present a progress report of the analysis of the spectra., Comment: 2 pages, 1 figure. To appear in the proceedings of the conference "Assembling the Puzzle of the Milky Way", Le Grand-Bornand, France, 17-22 April 2011, European Physical Journal, editors C. Reyl\'e, A. Robin and M. Schultheis

We present 4 model series of the CODEX dynamical opacity-sampling models of Mira variables with solar abundances, designed to have parameters similar to $o$ Cet, R Leo and R Cas. We demonstrate that the CODEX models provide a clear physical basis for the molecular shell scenario used to explain interferometric observations of Mira variables. We show that these models generally provide a good match to photometry and interferometry at wavelengths between the near-infrared and the radio, and make the model outputs publicly available. These model also demonstrate that, in order to match visible and infrared observations, the Fe-poor silicate grains that form within 3 continuum radii must have small grain radii and therefore can not drive the winds from O-rich Mira variables., Comment: 16 pages, 18 figures, accepted for MNRAS

The pulsation periods of long period variables (LPVs) depend on their mass and helium abundance as well as on their luminosity and metal abundance. Comparison of the observed periods of LPVs in globular clusters with models is capable of revealing the amount of mass lost on the giant branch and the helium abundance.} {We aim to determine the amount of mass loss that has occurred on the giant branches of the low metallicity globular clusters NGC 362 and NGC 2808. We also aim to see if the LPVs in NGC 2808 can tell us about helium abundance variations in this cluster.} We have used optical monitoring of NGC 362 and NGC 2808 to determine periods for the LPVs in these clusters. We have made linear pulsation models for the pulsating stars in these clusters taking into account variations in mass and helium abundance. Reliable periods have been determined for 11 LPVs in NGC 362 and 15 LPVs in NGC 2808. Comparison of the observed variables with models in the logP - K diagram shows that mass loss of ~0.15-0.2 Msun is required on the first giant branch in these clusters, in agreement with estimates from other methods. In NGC 2808, there is evidence that a high helium abundance of Y~0.4 is required to explain the periods of several of the LPVs. It would be interesting to determine periods for LPVs in other Galactic globular clusters where a helium abundance variation is suspected to see if the completely independent test for a high helium abundance provided by the LPVs can confirm the high helium abundance estimates., Comment: 13 pages, 12 figures, accepted for publication in Astronomy & Astrophysics

As shown by Mennickent, et al(2003), a subset of the blue variable stars in the Large Magellanic Cloud exhibit brightness variability of small amplitude in the period range 2.4 to 16 days as well as larger amplitude variability with periods of 140 to 600 days, with a remarkably tight relation between the long and the short periods. Our re-examination of these objects has led to the discovery of additional variability. The Fourier spectra of 11 of their 30 objects have 3 or 4 peaks above the noise level and a linear relation of the form f_a = 2(f_b - f_L) among three of the frequencies. An explanation of this relation requires an interplay between the binary motion and that of a third object. The two frequency relations together with the Fourier amplitude ratios pose a challenging modeling problem., Comment: 4 pages, 3 figures, Astrophysical Journal (in press)

A search for variable stars with ultra-low amplitudes (ULA), in the millimag range, has been made in the combined MACHO and OGLE data bases in the broad vicinity of the Cepheid instability strip in the HR diagram. A total of 25 singly periodic and 4 multiply periodic ULA objects has been uncovered. Our analysis does not allow us to distinguish between pulsational and ellipsoidal (binary) variability, nor between LMC and foreground objects. However, the objects are strongly clustered and appear to be associated with the pulsational instability strips of LMC Pop. I and II variables. When combined with the ULA variables of Buchler et al (2005) a total of 20 objects fall close to the classical Cepheid instability strip. However, they appear to fall on parallel period-magnitude relations that are shifted to slightly higher magnitude which would confer them a different evolutionary status. Low amplitude RV Tauri and Pop. II Cepheids have been uncovered that do not appear in the MACHO or OGLE catalogs. Interestingly, a set of binaries seem to lie on a PM relation that is essentially parallel to that of the RV Tauri/Pop. II Cepheids., Comment: 13 pages, 13 (color) figures. Astrophysical Journal (accepted for publlication)

We present spectroscopic observations from the {\it Spitzer Space Telescope} of six carbon-rich AGB stars in the Sagittarius Dwarf Spheroidal Galaxy (Sgr dSph) and two foreground Galactic carbon stars. The band strengths of the observed C$_2$H$_2$ and SiC features are very similar to those observed in Galactic AGB stars. The metallicities are estimated from an empirical relation between the acetylene optical depth and the strength of the SiC feature. The metallicities are higher than those of the LMC, and close to Galactic values. While the high metallicity could imply an age of around 1 Gyr, for the dusty AGB stars, the pulsation periods suggest ages in excess of 2 or 3 Gyr. We fit the spectra of the observed stars using the DUSTY radiative transfer model and determine their dust mass-loss rates to be in the range 1.0--3.3$\times 10^{-8} $M$_{\odot}$yr$^{-1}$. The two Galactic foreground carbon-rich AGB stars are located at the far side of the solar circle, beyond the Galactic Centre. One of these two stars show the strongest SiC feature in our present Local Group sample., Comment: 12 pages, 11 figures, accepted for publication in MNRAS