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This thesis concerns the use of data from the Gaia satellite to study Galactic planetary nebulae. Gaia is a recent ESA mission measuring positions, parallaxes, proper motions, and photometry of nearly two billion stars in the Milky Way. Several thousand of these stars are passing through the planetary nebula phase, an important phase that low and intermediate mass stars experience towards the ends of their lives before becoming white dwarfs. The thesis has three main contributions. The first is the development and application of an automated technique for identifying the central stars of planetary nebulae in the Gaia catalogue. The second is a statistical method for identifying photometric variability in these central stars. Periodic photometric variability is often an indicator of binarity, which is now known to be key to the formation and shaping of a significant fraction of planetary nebulae. The method is validated through ground-based follow up observations. Finally, more precise distances from Gaia parallaxes are combined with newly obtained ground-based narrowband imagery to determine and investigate the planetary nebula luminosity function of the local Milky Way. Besides being an important extragalactic indicator, this distribution of nebula magnitudes is related to the evolution of planetary nebula central stars across different masses. Distances and photometry from Gaia allow the brightness of the nebula and the evolution of the central star to be related directly in unprecedented detail.

Background Little research has been conducted on the impact of the coronavirus disease 2019 (COVID-19) pandemic on either birth outcomes or the ability of archival medical records to accurately capture these outcomes. Our study objective is thus to compare the prevalence of preterm birth, stillbirth, low birth weight (LBW), small for gestational age (SGA), congenital microcephaly, and neonatal bloodstream infection (NBSI) before and during the first wave of the COVID-19 pandemic in Kinshasa, Democratic Republic of Congo (DRC). Methods We conducted a facility-based retrospective cohort study in which identified cases of birth outcomes were tabulated at initial screening and subcategorized according to level of diagnostic certainty using Global Alignment of Immunization Safety Assessment in pregnancy (GAIA) definitions. Documentation of any birth complications, delivery type, and maternal vaccination history were also evaluated. The prevalence of each birth outcome was compared in the pre-COVID-19 (i.e., July 2019 to February 2020) and intra-COVID-19 (i.e., March to August 2020) periods via two-sample z-test for equality of proportions. Results In total, 14,300 birth records were abstracted. Adverse birth outcomes were identified among 22.0% and 14.3% of pregnancies in the pre-COVID-19 and intra-COVID-19 periods, respectively. For stillbirth, LBW, SGA, microcephaly, and NBSI, prevalence estimates were similar across study periods. However, the prevalence of preterm birth in the intra-COVID-19 period was significantly lower than that reported during the pre-COVID-19 period (8.6% vs. 11.5%, p Conclusion This study succeeded in providing prevalence estimates for key adverse birth outcomes using GAIA criteria during the COVID-19 pandemic in Kinshasa, DRC. Furthermore, our study adds crucial real-world data to the literature surrounding the impact of the COVID-19 pandemic on maternal and neonatal services and outcomes in Africa.

These documents are the stored online versions of the presentations given during the Microworkshop "Accessing the Gaia treasure trove with TOPCAT, STILTS, ADQL and Gaia Sky", held on Thursday, Nov. 3rd, 2022, at the ESO Chile headquarters in Vitacura, Chile. The 1st document deals with TOPCAT and STILTS, the second with TAP queries and the underlying ADQL language. Ths way, the participants of this workshop are enabled to access the material used during the event.

Purpose In accordance with Latour, this paper aims to respond to the call for a “down-to-earth” post-learning organization approach to sustainability, which is critical of Senge’s conception of learning organization (LO). Design/methodology/approach “Gaia storytelling” is used to define a LO that is “down-to-earth”. Findings Gaia is understood through the notion of a critical zone, which foregrounds the local and differentiated terrestrial conditions in which life on Earth is embedded. Practical implications Gaia storytelling implies perceiving LO as a network of storytelling practices enacted and told by unique creative citizens. Such an organization sustains and grows through several entangled storytelling cycles that allow Gaia to shape learning. Social implications The article distinguishes five different storytelling cycles as a way to explore how the Gaia theater cycle connects to other cycles. The four other cycles are: Gaia thinking, explorative, creative and Gaia truth-telling. Originality/value A Gaian LO is a new beginning for LO.

Dramatic advances in astronomical instrumentation and data processing power have transformed astrometry, over the last decades, from a narrow specialist field into a powerful standard tool for astronomical research. In the optical regime Gaia is the prime example of this, but parallel developments are happening in groundbased techniques and at other wavelengths. In this talk I outline some of the advances that have enabled this transformation and give examples from the amazingly rich variety of science applications of modern astrometry. Many more examples are given elsewhere at this meeting. It is clear that we have only seen the beginning of thís process: Gaia has yet to demonstrate the full extent of its capabilities and will be much expanded in depth and scope by other projects, the full synergies of which may only become apparent much later. The review ends with a few reflections on the long-term prospects and challenges of astrometry.

Herbig Ae/Be stars are intermediate mass pre-main sequence stars. The massive stars among Herbig Ae/Be stars (Herbig Be stars: B0-B3) are reported to accrete mass through boundary layer accretion, whereas the lower mass Herbig Ae/Be stars accrete through magnetospheric accretion. Interestingly, Herbig Be stars show a bi-modal nature in the near-infrared colors and the Hα equivalent widths. The stars with H-K > 1.0 and Hα EW > 50 Å (emission) are defined as Extreme Herbig Be stars. The difference is attributed to the presence and absence of envelopes around these stars. The total number of known Extreme Herbig Be stars is 11. We investigate the possibility of identifying more extreme Herbig Be stars with high Hα EW taken from Gaia BP/RP spectra and 2MASS NIR colors. We identified 14 candidates that satisfy the criteria of Extreme Herbig Be stars. Confirmation of their evolutionary status using spectroscopic follow-up will increase the total sample of Extreme Herbig Be stars up to 170%.

We introduce the application of the clustering algorithm to the preliminary compiled list of probable wide pairs of co-moving stars. The main aim of such development is a possibility of unsupervised blind search of coeval loose stellar structures over significant regions in space. Using Gaia EDR3 data, we investigated the application of the method to nearby region hosting recently discovered loose structures – tidal tails of Coma Ber star cluster and a nearby stellar group named Group X. We compare the results of straightforward clustering of stellar data with results of using our method with varying parameters. We then compare the results of our method to the recent results of the two groups of authors who independently discovered the discussed structures. We find parameters allowing the method to find the full scope of distributed stellar groups without preliminary knowledge of their characteristics. It decreases the risk of false positive clustering and improves the ability to discover loose stellar groups, in comparison with the application of clustering algorithm to the individual stars. Further we obtain a refined dataset of probable members of both stellar groups and independently obtain their ages (700 ± 70 Myr and 450 ± 100 Myr) and space velocities ((U,V,W) = (8.63 ± 0.13, 6.63 ± 0.20, 6.65 ± 0.95) km/s for Coma Ber star cluster, and (U,V,W) = (7.70 ± 0.12, 3.27 ± 0.45, 5.69 ± 0.80) km/s for Group X). Our results are in very good agreement with those of previous investigators.

Abstract: The stellivore hypothesis (Vidal 2014, Chap 9; Vidal 2016; Vidal 2020) proposes to reinterpret some known accreting binary star systems as Type II civilizations. A stellivore can be seen as a variation on the Dyson sphere idea, making the most of accretion power, instead of solar collectors. Since it was proposed, no clear refutation or confirmation has been advanced. What lacks are concrete predictions and data supporting them. Drawing on Gaia DR3 data, I present preliminary results of apparent goal-directed motions of stellivore candidates in the galactic field. Uncertainties remain, but I discuss how these could be reduced and mitigated. Goal-directedness is a hallmark of intentionality and intelligence, which, if proven with enough statistical significance would be thought-provoking. References: Vidal, C. 2014. The Beginning and the End - The Meaning of Life in a Cosmological Perspective. Frontiers Collection. Springer. http://arxiv.org/abs/1301.1648. ———. 2016. “Stellivore Extraterrestrials? Binary Stars as Living Systems.” Acta Astronautica 128: 251–56. doi:10.1016/j.actaastro.2016.06.038. https://zenodo.org/record/164853. ———. 2020. “Energy Rate Density as a Technosignature: The Case for Stellivores.” Presented at Life in the Universe: Big History, SETI and the Future of Humankind. IBHA & INAF-IASF MI Symposium 15-16 July 2019. http://www.clemvidal.com/s/Vidal-2020-ERD-as-a-technosignature-case-for-stellivores.pdf.

From the determination of the first occurrence rates by the Kepler Mission, small planets (< 4 Earth radii) have garnered outsize interest. Early Kepler occurrence rates showed that small planets are more abundant than their larger counterparts, but these analyses were limited by the precision of stellar radii. As a result, the planet radius gap – a relative minimum in occurrence separating super-Earths (< 1.8 Earth radii) from sub-Neptunes (>1.8 Earth radii) — was confirmed when the California-Kepler Survey precisely determined the properties of >1000 host stars hosting >2000 planets. Today, in the era of Gaiaphotometry and parallaxes and all-sky exoplanet transit surveys, homogeneous, precise stellar properties are possible for thousands of host stars enabling detailed studies of the gap. In this talk, I will present the discovery and subsequent Gaia-Era investigations of the exoplanet radius gap. I will discuss the gap’s potential origins and proposed formation mechanisms’ ability to explain the current observational data. Finally, I will discuss the prospects for differentiating between the various gap formation mechanisms, so that we may further understand planet formation and evolution for planets similar to our own.

Un autre langage se cherche, « à la limite de l’intelligible ». Comment peut-on aujourd’hui « se rapporter au monde », le penser et le dire, sans plus répéter les présupposés modernes, empêtrés que nous sommes dans les conséquences de leurs conséquences ? Comment ce monde, que nous connaissons si mal, « nous vient-il » s’il n’est plus seulement « un objet calculable et prévisible » ? Comment la Terre fait-elle intrusion, elle qui réagit à nos actions ? Questions qui constituent et traversent le champ de l’écocritique telle que nous la définissons. Il importe de penser ensemble pour inventer de nouveaux concepts, non toxiques, fabriquer des savoirs pertinents susceptibles de répondre à ce qui est en train d’arriver ; défaire et se défaire des réflexes et des préjugés de la modernité, promouvoir des récits qui supplantent nos fables obsolètes et expriment les bouleversements inédits dont nous faisons l’expérience. Les frontières disciplinaires peuvent-elles devenir des zones d’échanges, productrices d’intelligence ? L’écocritique peut-elle favoriser une « culture de la sympoïèse » (Haraway), inventer un sol commun où repousse la vie ? Another language is sought, « at the limit of the intelligible ». How can we today « relate to the world », think it and tell it, without repeating modern biases, entangled as we are in the consequences of their consequences? How may this world, one we so badly know, « come to us » if it is no longer only « a calculable and predictable object »? How may the Earth creep in, reacting to our actions? These questions shape and cross the field of ecocriticism as we define it. It is important to think together in order to invent new, non-toxic concepts, to create relevant knowledge that may respond to what is happening; to undo and to discard the reflexes and prejudices of modernity, to promote narratives that supplant our obsolete fables and express the unprecedented upheavals we are experiencing. Can disciplinary borders become zones of exchange, that may produce intelligence? Can ecocriticism foster a « culture of sympoiesis » (Haraway), inventing a common ground where life may grow anew?

Embracing science but suggesting an alternate explanation for global warming, the essay provides a thermodynamic and historical perspective on eco-destruction. From a long-term evolutionary perspective, caution is raised about the repetition of human exceptionalism implied by the popular term “Anthropocene,” which hyperbolically frames humankind as the first organism in evolutionary history, and uniquely dangerous at that, to threaten global life. In fact, cyanobacteria preceded technological humanity, altering Earth's atmospheric composition orders of magnitude more than humanity has. The extreme resilience of Gaia, planetary life taken as an open thermodynamic system with environmentally regulative tendencies, has undergone dramatic changes in the past, such as the production of an oxygen-rich atmosphere. Genetically nimble life, recycling matter on a planetary level, has evolved means of tempering the tendency of organisms to exponentially reproduce. Ironically, these means, some which appear to have evolved to titrate hypergrowth in animal clades via senescence, have so far escaped ecologically rapacious humans. Thermodynamically, modern technological humanity, for all its self-regard as an intelligent life form, resembles a ravaging fire or intrinsically short-lived storm system. Long-term human persistence in the global ecosystem will require changes in our epistemology, economics, and ecology.

This paper turns to the thought of Yan Thomas to address the way of constructing categories and operating through them that is typical of law. The art of law displays a special quality: the reduction of the ‘things’ of the social world through the construction of categories, and the use of these same categories to conduct legal operations. The paper argues that the quintessential legal performance is instituting, and it finally asks how to exercise a legal imagination for Gaia. Xenia Chiaramonte, ‘Law Is Other Wor(l)ds’, in The Case for Reduction, ed. by Christoph F. E. Holzhey and Jakob Schillinger, Cultural Inquiry, 25 (Berlin: ICI Berlin Press, 2022), pp. 227-50

Bruno Latour: Wo bin ich? Lektionen aus dem Lockdown. Berlin: Suhrkamp 2021. 978-3-518-12771-1

With the aim of better understanding the physical conditions under which Be stars form and evolve, it is imperative to further investigate whether poorly studied young open clusters host Be stars. In this work, we explain how data from Gaia DR2 and DR3 can be combined to recover and characterize active Be stars in open clusters. We test our methodology in four open clusters broadly studied in the literature, known for hosting numerous Be stars. In addition, we show that the disk formation and dissipation approach that is typically used to model long term Be star variability, can explain the observed trends for Be stars in a (GDR3-GDR2) versus GDR3 plot. We propose that extending this methodology to other open clusters, and, in particular, those that are poorly studied, will help to increase the number of Be candidates. Eventually, Be stars may eclipse binary systems in open clusters.

Hobbs, David, et al., The era of all-sky space astrometry began with the Hipparcos mission in 1989 and provided the first very accurate catalogue of apparent magnitudes, positions, parallaxes and proper motions of 120 000 bright stars at the milliarcsec (or milliarcsec per year) accuracy level. Hipparcos has now been superseded by the results of the Gaia mission. The second Gaia data release contained astrometric data for almost 1.7 billion sources with tens of microarcsec (or microarcsec per year) accuracy in a vast volume of the Milky Way and future data releases will further improve on this. Gaia has just completed its nominal 5-year mission (July 2019), but is expected to continue in operations for an extended period of an additional 5 years through to mid 2024. Its final catalogue to be released ∼ 2027, will provide astrometry for ∼ 2 billion sources, with astrometric precisions reaching 10 microarcsec. Why is accurate astrometry so important? The answer is that it provides fundamental data which underpin much of modern observational astronomy as will be detailed in this White Paper. All-sky visible and Near-InfraRed (NIR) astrometry with a wavelength cutoff in the K-band is not just focused on a single or small number of key science cases. Instead, it is extremely broad, answering key science questions in nearly every branch of astronomy while also providing a dense and accurate visible-NIR reference frame needed for future astronomy facilities., Open access funding provided by Lund University.

The Orion complex is one of the best-studied regions in the sky. It is the closest massive star-forming region to earth, which harbors molecular clouds and various stellar groups at different evolutionary stages (up to 20 Myr) and with different masses. Therefore, it offers the closest laboratory to study the formation of clusters and stellar groups in different environments on the same large gas complex. Recently, we were able to analyze the 6D phase space of the southern Orion molecular cloud complex by using Gaia observed YSOs as probes for cloud distance and proper motion. This is a valid approach, since these YSOs still reside close to their parental cloud and they share, on average, the same radial velocity as the gas. The results show an expansion of the studied clouds on the 100-pc scale, implying a feedback-driven star formation history, likely from previous generations of massive stars that formed early in Orion. We call this feedback event the Orion big-blast event (Orion-BB), which took place about 6 Myr ago, based on a dynamical traceback. This event was able to form, or at least shape and compress, the molecular gas and likely triggered/enhanced star formation in the region. Additionally, young stellar clusters in the region (𝛔Ori, NGC1977) seem to be affected similarly. Our analysis shows that young stars remember the motion of their parental cloud. Our results imply that by observing young open clusters in the solar neighborhood, we could learn about the star-forming region in which they formed. For Orion-like regions, the resulting outcome (stellar clusters, associations, groups) will have characteristic space motions traceable for about several ten Myr before they eventually settle at different and unrecognizable orbits in the Milky Way., Funding: The Austrian Research Promotion Agency FFG (AT), Grant Number 873708, https://www.ffg.at/en, {"references":["Großschedl et al. 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How stellar clusters form is a fundamental open question in modern astrophysics. Most young stars are observed in groups or clusters, still embedded in their natal molecular clouds. But, within 10 Myr, only about 10% of stars remain bound to their birth clusters. The vast majority of stars have already dispersed into the field, or are found in unbound stellar associations by this age. This raises the question: on what spatial scales do stars form co-evally? And for how long do the initial conditions, such as spatial configurations and kinematics preserve after stars de-couple from their natal gas? Using Gaia DR2 data, we have discovered a large scale (300 pc long), co-eval cigar-like structure that is compact in proper motions, and located about 400 pc from us. The relic filament is roughly 35 Myr old and connects four already known open star clusters and three newly discovered ones. The latest DR3 data, complemented with radial velocities, provide an even better and more precise picture of this structure. This allows us to see, almost frozen in time, an ensemble of young stellar clusters/groups just getting out of the original nascent filament. This is a unique event, picturing the status of young stars at the early stage of their life formed together co-evally on such an unexpectedly large spatial scale.

Signalling that ‘humanity’ has radically changed the Earth’s environmental parameters, the Anthropocene currently generates debate across the socio-cultural sciences. In this context, neo-Marxist and new materialist approaches stand out for the way they oblige social theory to catch up with new material realities. We share the conviction that the Anthropocene might constitute a genuine event for social theory and practice. However, we argue that the search for alternative ways of problematizing and ‘dramatizing’ our eco-political predicament confronts these approaches with unresolved issues of scientism and economic totalization. Looking for another path, we turn to Science and Technology Studies (STS), and especially Actor-Network Theory (ANT). We relay the long-standing focus on nonhuman agency characteristic of this field via Isabelle Stengers’ argument that we must ‘accept’ the reality of Gaia’s intrusion into collective historicity. The challenge posed by Stengers, we suggest, requires the development of an art of immanent attention to the politics of varied matters as they unfold across diverse ecologies of practice. Extending further than the present preoccupations of Euro-American social theory, other areas within and across environmental history, activism and politics offer sites of resistance as well as experimentation whose conceptual possibilities and practical efficacies have yet to be explored. Slowing down theory sufficiently to learn from these multiple sites, we argue, is the starting point for an approach more adequate to the problems posed by the Anthropocene event.

Toczące się od kilku lat dyskusje na temat nowej epoki w dziejach Ziemi koncentrują się na kwestiach wyboru adekwatnej nazwy i weryfikowalnego naukowo datowania. Lektura tekstów wokół antropocenu ujawnia właściwe dla różnych dyscyplin naukowych metodologie i narzędzia badawcze, a przede wszystkim pokazuje lokalność i sytuacyjność produkowanej przez każdą z nich wiedzy. Artykuł zaczyna się od przywołania remedium na katastrofalne skutki techno-naukowego postępu, które odwołując się do sił chtonicznych proponują Isabel Stangers, Donna Haraway i Bruno Latour. Choć nadają mu samo imię Gaja, odmiennie definiują otwarty i emergentny system powiązań sym-biotycznych, o którym pod koniec lat siedemdziesiątych pisał brytyjski fizjolog James Lovelock. Następnie przedstawia najważniejsze i konkurencyjne wobec antropocenu koncepcje: kapitalocen (Jason W. Moore), nekrocen (Justin McBrien) i plantacjocen (Anna Lowenhaupt Tsing), żeby przejść do idei prospektywnego i spekulacyjnego myślenia Donny Haraway (Staying with Trouble, 2016). Haraway zastanawia się nad przyszłością po antropocenie i tym, jak można odzyskać naturokulturową różnorodność. Dokonuje radykalnej redefinicji relacji między ludźmi a innymi, biotycznymi i abiotycznymi sprawczościami, niedostateczną uwagę poświęca jednak holobiontom z pogranicza biologii i nowoczesnych technologii, które pojawiają się w takich współczesnych projektach, jak przedstawiona w artykule Species Series koreańskiego artysty Wonbin Yanga (2012). A debate about a new era in the history of the Earth has been under way for almost two decades, but it has focused merely on an adequate naming and scientifically verifiable dating of that period. What has been written about the Anthropocene lays bare specificity of methodologies and approaches of various research fields, but above all demonstrates locality and situatedness of knowledge produced within each of them. The article starts with recalling a few remedies to catastrophic after-effects of the techno-scientific progress proposed by Isabel Stangers, Donna Haraway, and Bruno Latour, who refer to chthonic powers. Although they give these powers the same name Gaia, each of them differently defines an open-ended and emergent system of symbiotic relationships which was described by the British physiologist James Lovelock in the late 1970s. Next, the article presents the most important concepts of the new era that compete with the term “Anthropocene”: Capitalocene (Jason W. Moore), Necrocene (Justin McBrien), and Plantatiocene (Anna Lowenhaupt Tsing). Finally the article focuses on Donna Haraway’s idea of prospective and speculative fabulation (Staying with Trouble, 2016). Haraway outlines a future after the Anthropocene, speculating about how to salvage naturecultural variability. She offers a radical redefinition of relationships between humans and others critters, biotic and abiotic agencies. She does not focus extensively, however, on holobionts in border area of biology and modern technologies which emerge in such contemporary projects as Species Series of an Corean artist Wonbin Yanga (2012), analysed in the paper.

We present the first results of analysis of the structure and dynamics of the Vela OB2 association and nearby open clusters using a combination of Gaia eDR3 astrometry and spectroscopic radial velocities. We confirm the youth of sources in our sample using Lithium equivalent widths, identify velocity substructure and estimate rates of expansion for the Vela OB2 association. We find that the expansion of Vela OB2 is significantly anisotropic., {"references":["Armstrong J. J. et al. 2020, MNRAS, 494(4), 4794","Armstrong J. J. et al. 2018, MNRAS, 480, L121","de Zeeuw P. T. et al. 1999, AJ, 117, 354","Jeffries R. D. et al. 2014, A&A, 563, A94","Miville-Deschenes M.- A., Lagache G., 2005, ApJS, 157(2), 302","Prisinzano L. et al. 2016, A&A, 589, A70","Wright, N. J. 2020, NewAR, 90, 101549"]}

Theoretical models show the main sequence gap is a result of the mixing of 3He during the merger of envelope and core convection zones. Unlike stars the either side of the gap, stars in a narrow mass range will go through instability phases, where their dynamos could switch between the αΩ dynamo like the Sun and Ω2 dynamo like late M dwarfs. At the same time, they show radial pulsation and their fluxes fluctuate, which resemble the pulsations observed in evolved stars like red giants and asymptotic giant branch stars. Consequently, they are a unique type of dwarf like no other on the main sequence. In this work, we would like to know 1) will the unstable interior structures result in observable characteristics such as flaring and spots, and 2) what is the mass range for these stars observationally? Here we present our preliminary results: 1) stars in the gap have higher percentage rate of activities than their adjacent regions, and 2) high resolution speckle results yield promising close binaries to yield dynamical masses in the future.

We present a new census of candidate pre-main-sequence stars in the Cepheus flare star-forming region, based on Gaia EDR3 parallaxes, proper motions, and colour-magnitude diagrams. We identified new candidate members of the previously known young stellar groups associated with NGC 7023, L1177, L1217/L1219, L1228, L1235, and L1251. We studied the 3D structure of the star-forming complex and the distribution of tangential velocities of the young stars. The young stellar groups are located between 330 and 368 pc from the Sun, divided into three kinematic subgroups, and have ages between 1 and 5 million yr. The results confirm the scenario of propagating star formation, suggested by previous studies. In addition to the bulk pre-main-sequence star population between 330 and 370 pc, there is a scattered and more evolved pre-main-sequence population around 150-180 pc. We found new candidate members of the nearby Cepheus Association, and identified a new moving group of 46, 15-20 million yr old pre-main-sequence stars located at a distance of 178 pc, around the A0-type star HD 190833. A few pre-main-sequence stars are located at 800-900 pc, indicative of star-forming regions associated with the Galactic local arm above the Galactic latitude of +10°., Funding: ESA PRODEX Contract nr. 4000129910

La lecture du livre « Où suis-je ? » de Bruno Latour convainc que, au moins autant que l’enjeu écologique de la planète, c’est bien, dans son entière plénitude, la question de l’habiter qui est posée. Dès lors, les considérations écologiques, en particulier l’annonce apocalyptique de la fin, peuvent-elles être les entrées exclusives de cet enjeu pour l’humanité tout entière, soit chacun et chacune de ses membres, et bien au-delà encore ?

A sporadic E layer has significant influence on radio communications and broadcasting, and predicting the occurrence of sporadic E layers is one of the most important issues in space weather forecast. While sporadic E layer occurrence and the magnitude of the critical sporadic E frequency (foEs) have clear seasonal variations, significant day-to-day variations as well as regional and temporal variations also occur. Because of the highly complex behavior of sporadic E layers, the prediction of sporadic E layer occurrence has been one of the most difficult issues in space weather forecast. To explore the possibility of numerically predicting sporadic E layer occurrence, we employed the whole atmosphere–ionosphere coupled model GAIA, examining parameters related to the formation of sporadic E layer such as vertical ions velocities and vertical ion convergences at different altitudes between 90 and 150 km. Those parameters in GAIA were compared with the observed foEs data obtained by ionosonde observations in Japan. Although the agreement is not very good in the present version of GAIA, the results suggest a possibility that sporadic E layer occurrence can be numerically predicted using the parameters derived from GAIA. We have recently developed a real-time GAIA simulation system that can predict atmosphere–ionosphere conditions for a few days ahead. We present an experimental prediction scheme and a preliminary result for predicting sporadic E layer occurrence.

We report the results of the STRong lensing Insights from the Dark Energy Survey (STRIDES) follow-up campaign of the late 2017/early 2018 season. We obtained spectra of 65 lensed quasar candidates either with EFOSC2 on the NTT or ESI on Keck, which confirm 10 new gravitationally lensed quasars and 10 quasar pairs with similar spectra, but which do not show a lensing galaxy in DES images. Eight lensed quasars are doubly imaged with source redshifts between 0.99 and 2.90, one is triply imaged by a group (DESJ0345-2545, $z=1.68$), and one is quadruply imaged (quad: DESJ0053-2012, $z=3.8$). Singular isothermal ellipsoid models for the doubles, based on high-resolution imaging from SAMI on SOAR or NIRC2 on Keck, give total magnifications between 3.2 and 5.6, and Einstein radii between 0.49 and 1.97 arcseconds. After spectroscopic follow-up, we extract multi-epoch $grizY$ photometry of confirmed lensed quasars and contaminant quasar+star pairs from the first 4 years of DES data using parametric multi-band modelling, and compare variability in each system's components. By measuring the reduced ${\chi}^2$ associated with fitting all epochs to the same magnitude, we find a simple cut on the less variable component that retains all confirmed lensed quasars, while removing 94 per cent of contaminant systems with stellar components. Based on our spectroscopic follow-up, this variability information can improve selection of lensed quasars and quasar pairs from 34-45 per cent to 51-70 per cent, with the majority of remaining contaminants being compact star-forming galaxies. Using mock lensed quasar lightcurves we demonstrate that selection based only on variability will over-represent the quad fraction by 10 per cent over a complete DES magnitude-limited sample (excluding microlensing differences), explained by the magnification bias and hence lower luminosity (more variable) sources in quads., Comment: 22 pages, 16 figures, submitted to MNRAS

This Opinion and Hypothesis paper explores the Covid-19 pandemic against the background of global climate change. It is a cross-discipline study that examines interdependences in our environment at a hierarchy of scales; from the inner mind-body system, to the interactions of individuals within society, to at the outermost level the interactions of complete societies with the planet. These interactions are described as hierarchical Markov-blanket systems, whose properties shed light on how such hierarchical interactions may become unstable, contributing to reciprocal chaotic and destructive change at the outer level of climate change, and at the inner societal level evidenced by the current Coronavirus pandemic.

Bruno Latour is one of the founding figures in social network theory and a broadly influential systems thinker. Although his work has always been relational, little scholarship has engaged the relational morality, ontology, and epistemology of feminist care ethics with Latour’s actor–network theory. This article is intended as a translation and a prompt to spur further interactions. Latour’s recent publications, in particular, have focused on the new climate regime of the Anthropocene. Care theorists are just beginning to address posthuman approaches to care. The argument here is that Latourian analysis is helpful for such explorations, given that caring for the earth and its inhabitants is the dire moral challenge of our time. The aim here is not to characterize Latour as a care theorist but rather as a provocative scholar who has much to say that is significant to care thinking. We begin with a brief introduction to Latour’s scholarship and lexicon, followed by a discussion of care theorist Puig de la Bellacasa’s work on Latour. We then explore recent work on care and the environment consistent with a Latourian approach. The conclusion reinforces the notion that valuing relationality across humans and non-human matter is essential to confronting the Anthropocene.

In this paper, we propose an extension of the PROMETHEE methods. Despite PROMETHEE are among the most applied methods in Multiple Criteria Decision Aiding (MCDA), some drawbacks can be underlined with respect to their applicability since they do not take into account few characteristics of multicriteria decision problems that are very relevant in real world applications: (i) robustness regarding the plurality of compatible preference parameters; (ii) interaction between criteria; (iii) hierarchies of criteria. Even if different extensions of the PROMETHEE methods have taken into account all these aspects singularly, we propose to deal with all of them simultaneously presenting a new version which incorporates Robust Ordinal Regression (ROR), Stochastic Multicriteria Acceptability Analysis (SMAA), bipolar Choquet integral and Multiple Criteria Hierarchy Process (MCHP). ROR and SMAA permit to consider all the instances of the considered preference model compatible with the preference information provided by the DM; the bipolar Choquet integral is able to represent the possible positive and negative interactions between criteria as well as the antagonistic effect between some of them; finally, the MCHP permits to decompose the problem in small parts so that each of them can be analyzed more in detail with respect to the problem at hand. Moreover, we also introduce an extension of the GAIA technique to handle visualization in MCDA problems presenting interactions and antagonistic effects between criteria organized in a hierarchy. Furthermore it gives the possibility to display the plurality of instances of the preference model considered by SMAA. A didactic example will illustrate the proposed methodology.

This article considers some metaphysical and theological implications of the Anthropocene, which is the proposed name for a new geological epoch that is characterized by massive human disturbances of the Earth system. This stratigraphic time unit concludes the Holocene epoch that offered a relatively stable climate for human civilizations to emerge and flourish. The Anthropocene therefore marks the end of such natural stabilities - both real and imagined - along with a growing awareness of the dynamic agency or subjectivity of the Earth. By magnifying nonhuman subjectivity, the new epoch is widely interpreted by scholars across a range of disciplines as unsettling modern dualistic notions of human exceptionalism. Consequently, nonhuman nature is no longer a relatively inert background for human cultural activities. Humans and nonhumans must now be seen as interrelated Earth subjects. This nonmodern perspective suggests an ecological metaphysics of intersubjectivity along the lines of Alfred North Whitehead’s philosophy of organism, which redistributes subjectivity, creativity, and transcendence throughout nature. Theology in the Anthropocene must therefore account for this nondual view of reality, which arguably implies a divine-world relation characterized by mutual immanence. The proposed earthbound theology ultimately envisions the divine as poetic exemplification of intersubjectivity.

O artigo discute a desmistificação de Gaia na cultura grega que levou ao surgimento da ciência grega com Aristóteles que fundamentou a ciência helênica com Teofrasto e Estrabão. Dos jônicos, passando por Heráclito, e os atomistas até Hipócrates, a razão grega procurou em entender e explicar a origem do homem e da Terra não mais por meio dos mitos, mas sim buscando evidências na própria dinâmica da natureza, elegendo em cada momento histórico, elementos da natureza que melhor sintetizassem a origem natural, assim como a unidade metafísica e ontológica do mundo. L'article traite de la démystification de Gaia dans la culture grecque qui a conduit à l'émergence de la science grecque avec Aristote qui a basé la science hellénique avec Théophraste et Strabon. Des Ioniens en passant par Héraclite et des atomistes à Hippocrate, la raison grecque cherchait à comprendre et à expliquer l'origine de l'homme et de la terre non plus à travers des mythes, mais à la recherche de preuves dans la dynamique même de la nature, en mettant en valeur à chaque moment historique des éléments de la nature qui synthétisent le mieux à l’origine naturelle, ainsi que l’unité métaphysique et ontologique du monde. The article discusses the demystification of Gaia in Greek culture that led to the emergence of Greek science with Aristotle, the base of Hellenic science with Theophrastus and Strabo. From the Ionians to Heraclitus and the atomists to Hippocrates, the Greek reason sought to understand and explain the origin of man and the earth no longer through myths, but in search of evidence in the very dynamics of nature, by highlighting at each historical moment the elements of nature that best synthesize the natural origin, as well as the metaphysical and ontological unity of the world.

O artigo tem por objetivo discutir o papel do mito de Gaia na formação da ciência geográfica. Para tal objetivo, foram analisadas as obras Ilídada e Odisséia de Homero, os Hinos Homéricos, Teogonia – a origem dos deuses de Hesíodo e as obras Órficas, que permitiram entender o papel do mito de Gaia na construção da primeira interpretação geográfica no que tange à origem e a dinâmica de transformação da Terra, permitindo o desenvolvimento da ciência na antiguidade. O foco inicial recaiu na busca da compreensão da fisiologia e da fisiografia de Gaia pelos pré-socráticos, momento que surgiu o conceito de Kosmos, que pôs fim ao mito de Gaia. Foi a partir desta arquitetura que se desenvolveu a ciência geográfica no helenismo, cujo auge foram os trabalhos de Teofrasto e Estrabão, que influenciaram a própria constituição ciência geográfica na modernidade. L'article vise à discuter du rôle du mythe Gaia dans la formation de la science géographique. À cette fin, sont analysées les œuvres Illidade et Odyssée, d'Homère, les Hymnes homériques, Théogonie - l’origine des dieux d'Hésiode et les œuvres orphiques, qui nous ont permis de comprendre le rôle du mythe Gaia dans la construction de la première interprétation géographique origine et la dynamique de la transformation de la terre, permettant le développement de la science dans les temps anciens. L'objectif initial était de rechercher une compréhension pré-socratique de la physiologie et de la physiographie de Gaia, moment auquel le concept de Cosmos a émergé, mettant fin au mythe de Gaia. C'est à partir de cette architecture que la science géographique s'est développée dans l'hellénisme, dont l'apogée a été l'œuvre de Théophraste et de Strabon, qui ont influencé la constitution même de la science géographique dans la modernité. This article aims to discuss the participation of the myth of Gaia in the formation of geographical science in antiquity. For this purpose, Homer´s The Iliad and the Odyssey, the Homeric Hymns, The origin of the world and the gods according Hesiod's Theogony and the Orphic manuscripts have been used in order to understand the role of the Gaia myth in the construction of the first geographical interpretation related to Earth's origin and transformation, allowing the development of science in antiquity. The initial focus was directed to search the pre-Socratic understanding of the physiology and physiography of Gaia while the concept of Kosmos arose, decreeing the end of Gaia. It was from the architecture that Geographical science has developed in Hellenism taking for granted its peak moment in the work of Theophrastus and Strabo that notable influenced the constitution of geographical science in modernity.

We present estimates of the distances; ages and masses for nearly 5;5 million stars from public spectroscopic surveys. To derive these estimates we use Gaia DR2 parallax values; spectroscopic parameters as well as infra-red photometry. These estimates were obtained with the third version of the Unified tool to estimate Distances; Ages; and Masses (UniDAM); which introduced the use of optical photometry and (where available) asteroseismic data.

The dynamical history of the Milky Way is complicated. We see a lot of substructure (that is likely accreted), both in spatial density, and in kinematics. The complexity varies, from simple streams to phase-mixed structures that can only be separated by invariants such as stellar chemistry. To complicate things further, the Galaxy has non-axisymmetric structures such as the bar and multiple spiral arms. Due to their large scale-lengths, the kinematic signatures of such features often overlap, making it difficult to relate to one culprit or another. With the aid of high precision spectroscopy and astrometry, combined with dynamical modelling, we can make an attempt at understanding the various underlying causes of non-axisymmetric motions in the Galaxy. In this thesis, we adopt this multi-pronged approach that combines predictive models with high precision data. We explore the signatures of non-axisymmetry on both the local and global phase-space in the Galaxy. In the first part, we use kinematical modelling to quantify bulk motion in the line-of-sight velocity field of the disc, and place limits on the derived amplitudes accounting for systematics/limitations in the data. In the second part, we reveal new global phase-space structure in the Galaxy, and study it in the context of the perturbative effects of both internal (bar/spiral structure) and external (satellite galaxies) sources. Our findings suggest that the nature of spiral arms in our Galaxy might be transient.

Aims. Several kinematic and chemical substructures have been recently found amongst Milky Way halo stars with retrograde motions. It is currently unclear how these various structures are related to each other. This Letter aims to shed light on this issue. Methods. We explore the retrograde halo with an augmented version of the Gaia DR2 RVS sample, extended with data from three large spectroscopic surveys, namely RAVE, APOGEE and LAMOST. In this dataset, we identify several structures using the HDBSCAN clustering algorithm. We discuss their properties and possible links using all the available chemical and dynamical information. Results. In concordance with previous work, we find that stars with [Fe/H] $-1$. The retrograde halo contains a mixture of debris from objects like Gaia-Enceladus, Sequoia, and even the chemically defined thick-disc. We find that the Sequoia has a smaller range in orbital energies than previously suggested and is confined to high-energy. Sequoia could be a small galaxy in itself, but since it overlaps both in integrals-of-motion space and chemical abundance space with the less bound debris of Gaia-Enceladus, its nature cannot be fully settled yet. In the low-energy part of the halo we find evidence for at least one more distinct structure: Thamnos. Stars in Thamnos are on low inclination, mildly eccentric retrograde orbits, moving at $v_{\phi}\approx-150$ km/s, and are chemically distinct from the other structures. Conclusions. Even with the excellent Gaia DR2 data it remains challenging to piece together all the fragments found in the retrograde halo. At this point, we are very much in need of large datasets with high-quality high-resolution spectra and tailored high-resolution hydrodynamical simulations of galaxy mergers., Comment: 6 pages, 5 figures, submitted to A&A

Galactic astrophysics is now in the process of building a multi-dimensional map of the Galaxy. For such a map, stellar ages are the essential ingredient. Ages are however measured only indirectly by comparing observational data with models. It is often difficult to provide a single age value for a given star, as several non-overlapping solutions are possible. We aim at recovering the underlying log(age) distribution from the measured log(age) probability density function for an arbitrary set of stars. We build an age inversion method, namely, we represent the measured log(age) probability density function as a weighted sum of probability density functions of mono-age populations. Weights in that sum give the underlying log(age) distribution. Mono-age populations are simulated so that the distribution of stars on the log g-[Fe/H] plane is close to that of the observed sample. We tested the age inversion method on simulated data, demonstrating that it is capable of properly recovering the true log(age) distribution for a large (N > 103) sample of stars. The method was further applied to large public spectroscopic surveys. For RAVE-on, LAMOST and APOGEE we also applied age inversion to mono-metallicity samples, successfully recovering age-metallicity trends present in higher-precision APOGEE data and chemical evolution models. We conclude that applying an age inversion method as presented in this work is necessary to recover the underlying age distribution of a large (N > 103 ) set of stars. These age distributions can be used to explore for instance age-metallicity relations., 15 pages, 15 figures

EnglishWhen we think about the eὕρησις of fire in Ancient Greece, we think about Prometheus’ myth. But in ancient sources we can read many clues about an origin of fire from the earth. To set together these stories by an anthropological point of view, may lead to shed a light on ancient perspectives about the many meanings and functions of Earth in everyday life. italianoL’ eὕρησις del fuoco nell’Antica Grecia e generalmente abbinata al mito di Prometeo. Ma nelle fonti antiche sono presenti numerose tracce di una narrazione mitica secondo cui l’origine del fuoco era da ricondurre anche a Gaia e alla terra. Tale narrazione mitica sembra presentare una stretta connessione con dati ed esperienze appartenenti al vissuto dell’uomo greco, per il quale Gaia / la terra risulterebbe connessa a funzioni ampie e fondamentali.

Es bien sabido que la cultura popular contiene una gran variedad de mitos. En el mundo que el cineasta James Cameron plasmó en el film Avatar resulta sencillo distinguir una representación del Mito de Gaia. Sin embargo, el film también puede ser analizado desde una perspectiva ecocrítica. Por ende, el siguiente artículo analizará, mediante una revisión de dicho mito y también de las hipótesis de James Lovelock, cómo Gaia está presente en el planeta Pandora y es perfectamente reconocible en la figura de Eywa. Basándonos en la ecocrítica, veremos que la visión del planeta Pandora es aquella donde prima la defensa del universo natural y de los Na’vi, que, como grupo más débil y oprimido, logrará superar las adversidades y vencer los intereses de una sociedad moderna que busca extraer recursos naturales a cualquier precio.

We present six new time-delay measurements obtained from Rc-band monitoring data acquired at the Max Planck Institute for Astrophysics (MPIA) 2.2 m telescope at La Silla observatory between October 2016 and February 2020. The lensed quasars HE 0047−1756, WG 0214−2105, DES 0407−5006, 2M 1134−2103, PSJ 1606−2333, and DES 2325−5229 were observed almost daily at high signal-to-noise ratio to obtain high-quality light curves where we can record fast and small-amplitude variations of the quasars. We measured time delays between all pairs of multiple images with only one or two seasons of monitoring with the exception of the time delays relative to image D of PSJ 1606−2333. The most precise estimate was obtained for the delay between image A and image B of DES 0407−5006, where τAB = −128.4−3.8+3.5 d (2.8% precision) including systematics due to extrinsic variability in the light curves. For HE 0047−1756, we combined our high-cadence data with measurements from decade-long light curves from previous COSMOGRAIL campaigns, and reach a precision of 0.9 d on the final measurement. The present work demonstrates the feasibility of measuring time delays in lensed quasars in only one or two seasons, provided high signal-to-noise ratio data are obtained at a cadence close to daily.

Gravitationally lensed quasars are useful for studying astrophysics and cosmology, and enlarging the sample size of lensed quasars is important for multiple studies. In this work, we develop a lens search algorithm for four-image (quad) lensed quasars based on their time variability. In the development of the lens search algorithm, we constructed a pipeline simulating multi-epoch images of lensed quasars in cadenced surveys, accounting for quasar variabilities, quasar hosts, lens galaxies, and the PSF variation. Applying the simulation pipeline to the Hyper Suprime-Cam (HSC) transient survey, we generated HSC-like difference images of the mock lensed quasars from Oguri & Marshall's lens catalog. We further developed a lens search algorithm that picks out variable objects as lensed quasar candidates based on their spatial extent in the difference images. We tested our lens search algorithm with the mock lensed quasars and variable objects from the HSC transient survey. Using difference images from multiple epochs, our lens search algorithm achieves a high true-positive rate (TPR) of 90.1% and a low false-positive rate (FPR) of 2.3% for the bright quads with wide separation. With a preselection of the number of blobs in the difference image, we obtain a TPR of 97.6% and a FPR of 2.6% for the bright quads with wide separation. Even when difference images are only available in one single epoch, our lens search algorithm can still detect the bright quads with wide separation at high TPR of 97.6% and low FPR of 2.4% in the optimal seeing scenario, and at TPR of $\sim94%$ and FPR of $\sim5%$ in typical scenarios. Therefore, our lens search algorithm is promising and is applicable to ongoing and upcoming cadenced surveys, particularly the HSC transient survey and the Rubin Observatory Legacy Survey of Space and Time, for finding new lensed quasar systems. [abridged], 15 pages, 11 figures

We present the final sample of 98 detached double white dwarf (WD) binaries found in the Extremely Low Mass (ELM) Survey, a spectroscopic survey targeting M He-core WDs completed in the Sloan Digital Sky Survey footprint. Over the course of the survey we observed ancillary low-mass WD candidates like GD 278, which we show is a P = 0.19 day double WD binary, as well as candidates that turn out to be field blue straggler/subdwarf A-type stars with luminosities too high to be WDs given their Gaia parallaxes. Here, we define a clean sample of ELM WDs that is complete within our target selection and magnitude range 15 g(0) P

The Gaia mission and the stellar physics

Astrometry from space has unique advantages over ground-based observations: the all-sky coverage, relatively stable, and temperature and gravity invariant, operating environment delivers precision, accuracy and sample volume several orders of magnitude greater than ground-based results. Even more importantly, absolute astrometry is possible. The European Space Agency Cornerstone mission Gaia is delivering that promise. Gaia provides 5-D phase space measurements, 3 spatial coordinates and two space motions in the plane of the sky, for a representative sample of the Milky Way’s stellar populations (over 2billion stars, being ~1% of the stars over 50% of the radius). Full 6-D phase space data is delivered from line-of-sight (radial) velocities for the 300million brightest stars. These data make substantial contributions to astrophysics and fundamental physics on scales from the Solar System to cosmology. Reliable parallax distances in astronomy were available for of order 10^4 stars to milliarcsec (mas) precision in the 1980s, for of order 10^5 stars to mas accuracy in the 2000s, and with Gaia for more than 10^9 stars to 10μas accuracy. A knowledge revolution is underway., European Research Council (320360)

The goal of my work is to address the topic of the formation and evolution of the Galactic disk through the properties of open clusters. During my PhD I use photometric and astrometric data to derive open clusters properties such as distance, age, proper motions and metallicity. The aim is to take advantage of the high quality astrometry and photometry of first Gaia data release to build a homogeneous data base and to improve the cluster census. This is the first step towards Gaia second data release exploitation. To analyze large samples of data I develop and validate an automated pipeline. This includes: 1) BASE-9, a free available automated Bayesian analysis tool for parameters determination of stellar clusters, and the automated procedure UPMASK (free available). This procedure uses Principal Component Analysis and k-means clustering to select stars having similar properties on the photometric planes to determine the membership probability. In this work I improve it to deal also with astrometric data. I also improve BASE-9 in order to work with PARSEC isochrones I make use of ESO archive data to analyse the photometry and derive the physical parameters of three clusters namely NGC 2225, NGC 6134 and NGC 2243. I re-analyzed them with BASE-9 to compare the two methods. I used the Gaia first data release parallaxes and proper motions (TGAS), complemented with UCAC4 data, to study a sample of 134 OCs, and the data of the Hot Stuff for One Years catalog to study a sample of 13 OCs. I derived candidate members, proper motions and parallaxes for a sample of about 150 OCs. Using BASE-9 I inferred age, distance and extinction for 39 OCs and metallicity for 34 OCs. Finally, using the Python library galpy, I calculated the orbit of 36 OCs. I find evidences of vertical heating already effective at the time defined by the age of our clusters (~ 1Gyr). No evident sign of radial heating is detected in the same timescale.

Results of comparison of Gaia DR2 parallaxes with data derived from a combined analysis of 2MASS (Two Micron All-Sky Survey), SDSS (Sloan Digital Sky Survey), GALEX (Galaxy Evolution Explorer), and UKIDSS (UKIRT Infrared Deep Sky Survey) surveys in four selected high-latitude | b | &gt, 48&deg, sky areas are presented. It is shown that multicolor photometric data from large modern surveys can be used for parameterization of stars closer than 4400 pc and brighter than g S D S S = 19 . m 6 , including estimation of parallax and interstellar extinction value. However, the stellar luminosity class should be properly determined.

The painting activity is one of the most complex and important activities in automobile manufacturing. The inherent complexity of the painting activity and the frequent need for repainting usually turn the painting process into a bottleneck in automobile assembly plants, which is reflected in higher operating costs and longer overall cycle times. One possible approach for optimizing the performance of the paint shop is to improve the efficiency of the color planning. This can be accomplished by evaluating the relative merits of a set of vehicle painting plans. Since this problem has a multicriteria nature, we resort to the multicriteria decision analysis (MCDA) methodology to tackle it. A recent trend in the MCDA field is the development of hybrid approaches that are used to achieve operational synergies between different methods. Here we apply, for the first time, an integrated approach that combines the strengths of the analytic hierarchy process (AHP) and the Preference Ranking Organization METHod for Enrichment Evaluations (PROMETHEE), aided by Geometrical Analysis for Interactive Aid (GAIA), to the problem of assessing alternative vehicle painting plans. The management of the assembly plant found the results of value and is currently using them in order to schedule the painting activities such that an enhancement of the operational efficiency of the paint shop is obtained. This efficiency gain has allowed the management to bid for a new automobile model to be assembled at this specific plant.

It has now become an important issue to evaluate the performance of technical institu- tions to develop better research and enrich the existing teaching processes. The results of such per- formance appraisal would serve as a reference point for decisions to choose a particular institution, hire manpower, and provide financial support for the betterment of students and underperforming institutions. The performance of institutions responsible for promotion of technical education in a vast country, like India also needs to be assessed for its journey to share a major role in global economy. In this paper, an integrated approach combining PROMETHEE (Preference Ranking Organization METHod for Enrichment Evaluation) and GAIA (Geometrical Analysis for Interac- tive Aid) methods is applied for evaluating the performance of 20 National Institutes of Technol- ogy (NITs) in India with respect to nine pivotal criteria. It is observed that NIT, Tiruchirappalli and NIT, Warangal are the two best performers based on the last five years data. On the other hand, NIT, Patna takes the last position in the ranking list of 20 NITs suggesting allocation of more resources for its efficient management and subsequent development. Placement of the graduated students from those NITs is found to be the most important criterion.

The Internet is ubiquitous in our daily lives, but this holds true only for those who can afford it. As telecommunications operators deploy infrastructure and provide Internet services based on profit and regulations, billions of people are still digitally-disconnected. The only solution for these unsatisfied users is to build themselves the infrastructure required for obtaining access to the Internet. This article presents a global classification and a summary of the main characteristics of different Alternative Network deployments arisen in the last years with an aim to provide Internet services, where mainstream network deployments do not exist or are not the preferred solution. The “Global Access to the Internet for All” Working Group of the Internet Research Task Force, where all authors actively participate, is interested in documenting these emerging deployments. As an outcome of this work, a classification has converged by consensus, where five classification criteria have been identified and, based on them, four different types of Alternative Networks have been identified, which we describe along with real examples for each of them. Such a classification is useful for a deeper understanding of the common characteristics behind existing and emerging Alternative Networks.

The disruption of the climate : thinking what is coming with Bruno Latour. In his contribution Serge Gutwirth presents Bruno Latour’s article by describing the issue of climate disruption and the geopolitical and philosophical debates it raises., Dans sa contribution Serge Gutwirth présente l’article de Bruno Latour en décrivant la question du bouleversement climatique et des discussions géopolitiques et philosophiques qu’il implique., Gutwirth Serge. Bouleversement climatique : penser ce qui vient avec Bruno Latour. In: Revue Juridique de l'Environnement, n°1, 2014. pp. 45-50.

We propose a new way to search for hypervelocity stars in the Galactic bulge, by using red clump (RC) giants, that are good distance indicators. The 2nd Gaia Data Release and the near-IR data from the VISTA Variables in the Via Lactea (VVV) Survey led to the selection of a volume limited sample of 34 bulge RC stars. A search in this combined data set leads to the discovery of seven candidate hypervelocity red clump stars in the Milky Way bulge. Based on this search we estimate the total production rate of hypervelocity RC stars from the central supermassive black hole (SMBH) to be $N_{HVRC} = 3.26 \times 10^{-4} $ yr$^{-1}$. This opens up the possibility of finding larger samples of hypervelocity stars in the Galactic bulge using future surveys, closer to their main production site, if they are originated by interactions of binaries with the central SMBH., Comment: 9 pages, 2 figures, 4 subfigures, 3 tables. Accepted for publication in ApJL