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1.	Abolfathi, Bela, et al. (författare) The Fourteenth Data Release of the Sloan Digital Sky Survey : First Spectroscopic Data from the Extended Baryon Oscillation Spectroscopic Survey and from the Second Phase of the Apache Point Observatory Galactic Evolution Experiment 2018 Ingår i: Astrophysical Journal Supplement Series. - : IOP Publishing Ltd. - 0067-0049 .- 1538-4365. ; 235:2 Tidskriftsartikel (refereegranskat)abstract The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes the second data release from this phase, and the 14th from SDSS overall (making this Data Release Fourteen or DR14). This release makes the data taken by SDSS-IV in its first two years of operation (2014-2016 July) public. Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey; the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data-driven machine-learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from the SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS web site (www.sdss.org) has been updated for this release and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020 and will be followed by SDSS-V.
2.	Blanton, Michael R., et al. (författare) Sloan Digital Sky Survey IV : Mapping the Milky Way, Nearby Galaxies, and the Distant Universe 2017 Ingår i: Astronomical Journal. - : IOP Publishing Ltd. - 0004-6256 .- 1538-3881. ; 154:1 Tidskriftsartikel (refereegranskat)abstract We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and. high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z similar to 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z similar to 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs. and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the. Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July.
3.	The Seventeenth Data Release of the Sloan Digital Sky Surveys : Complete Release of MaNGA, MaStar, and APOGEE-2 Data 2022 Ingår i: Astrophysical Journal Supplement Series. - : Institute of Physics (IOP). - 0067-0049 .- 1538-4365. ; 259:2 Tidskriftsartikel (refereegranskat)abstract This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.
4.	Aguado, D. S., et al. (författare) The Fifteenth Data Release of the Sloan Digital Sky Surveys : First Release of MaNGA-derived Quantities, Data Visualization Tools, and Stellar Library 2019 Ingår i: Astrophysical Journal Supplement Series. - : Institute of Physics Publishing (IOPP). - 0067-0049 .- 1538-4365. ; 240:2 Tidskriftsartikel (refereegranskat)abstract Twenty years have passed since first light for the Sloan Digital Sky Survey (SDSS). Here, we release data taken by the fourth phase of SDSS (SDSS-IV) across its first three years of operation (2014 July-2017 July). This is the third data release for SDSS-IV, and the 15th from SDSS (Data Release Fifteen; DR15). New data come from MaNGA-we release 4824 data cubes, as well as the first stellar spectra in the MaNGA Stellar Library (MaStar), the first set of survey-supported analysis products (e.g., stellar and gas kinematics, emission-line and other maps) from the MaNGA Data Analysis Pipeline, and a new data visualization and access tool we call "Marvin." The next data release, DR16, will include new data from both APOGEE-2 and eBOSS; those surveys release no new data here, but we document updates and corrections to their data processing pipelines. The release is cumulative; it also includes the most recent reductions and calibrations of all data taken by SDSS since first light. In this paper, we describe the location and format of the data and tools and cite technical references describing how it was obtained and processed. The SDSS website (www.sdss.org) has also been updated, providing links to data downloads, tutorials, and examples of data use. Although SDSS-IV will continue to collect astronomical data until 2020, and will be followed by SDSS-V (2020-2025), we end this paper by describing plans to ensure the sustainability of the SDSS data archive for many years beyond the collection of data.
5.	Griffith, Emily, et al. (författare) The Similarity of Abundance Ratio Trends and Nucleosynthetic Patterns in the Milky Way Disk and Bulge 2021 Ingår i: Astrophysical Journal. - : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 909:1 Tidskriftsartikel (refereegranskat)abstract We compare abundance ratio trends in a sample of similar to 11,000 Milky Way bulge stars (R-GC < 3 kpc) from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) to those of APOGEE stars in the Galactic disk (5 kpc < R-GC < 11 kpc). We divide each sample into low-Ia (high-[Mg/Fe]) and high-Ia (low-[Mg/Fe]) populations, and in each population, we examine the median trends of [X/Mg] versus [Mg/H] for elements X = Fe, O, Na, Al, Si, P, S, K, Ca, V, Cr, Mn, Co, Ni, Cu, and Ce. To remove small systematic trends of APOGEE abundances with stellar log(g), we resample the disk stars to match the log(g) distributions of the bulge data. After doing so, we find nearly identical median trends for low-Ia disk and bulge stars for all elements. High-Ia trends are similar for most elements, with noticeable (0.05-0.1 dex) differences for Mn, Na, and Co. The close agreement of abundance trends (with typical differences less than or similar to 0.03 dex) implies that similar nucleosynthetic processes enriched bulge and disk stars despite the different star formation histories and physical conditions of these regions. For example, we infer that differences in the high-mass slope of the stellar initial mass function between disk and bulge must have been less than or similar to 0.30. This agreement, and the generally small scatter about the median sequences, means that one can predict all of a bulge star's APOGEE abundances with good accuracy knowing only its measured [Mg/Fe] and [Mg/H] and the observed trends of disk stars.
6.	Hasselquist, Sten, et al. (författare) APOGEE Chemical Abundance Patterns of the Massive Milky Way Satellites 2021 Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 923:2 Tidskriftsartikel (refereegranskat)abstract The SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey has obtained high-resolution spectra for thousands of red giant stars distributed among the massive satellite galaxies of the Milky Way (MW): the Large and Small Magellanic Clouds (LMC/SMC), the Sagittarius Dwarf Galaxy (Sgr), Fornax (Fnx), and the now fully disrupted Gaia Sausage/Enceladus (GSE) system. We present and analyze the APOGEE chemical abundance patterns of each galaxy to draw robust conclusions about their star formation histories, by quantifying the relative abundance trends of multiple elements (C, N, O, Mg, Al, Si, Ca, Fe, Ni, and Ce), as well as by fitting chemical evolution models to the [α/Fe]-[Fe/H] abundance plane for each galaxy. Results show that the chemical signatures of the starburst in the Magellanic Clouds (MCs) observed by Nidever et al. in the α-element abundances extend to C+N, Al, and Ni, with the major burst in the SMC occurring some 3-4 Gyr before the burst in the LMC. We find that Sgr and Fnx also exhibit chemical abundance patterns suggestive of secondary star formation epochs, but these events were weaker and earlier (∼5-7 Gyr ago) than those observed in the MCs. There is no chemical evidence of a second starburst in GSE, but this galaxy shows the strongest initial star formation as compared to the other four galaxies. All dwarf galaxies had greater relative contributions of AGB stars to their enrichment than the MW. Comparing and contrasting these chemical patterns highlight the importance of galaxy environment on its chemical evolution.
7.	Imig, Julie, et al. (författare) A Tale of Two Disks : Mapping the Milky Way with the Final Data Release of APOGEE 2023 Ingår i: Astrophysical Journal. - : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 954:2 Tidskriftsartikel (refereegranskat)abstract We present new maps of the Milky Way disk showing the distribution of metallicity ([Fe/H]), alpha-element abundances ([Mg/Fe]), and stellar age, using a sample of 66,496 red giant stars from the final data release (DR17) of the Apache Point Observatory Galactic Evolution Experiment survey. We measure radial and vertical gradients, quantify the distribution functions for age and metallicity, and explore chemical clock relations across the Milky Way for the low-a disk, high-alpha disk, and total population independently. The low-alpha disk exhibits a negative radial metallicity gradient of -0.06 +/- 0.001 dex kpc(-1), which flattens with distance from the midplane. The high-alpha disk shows a flat radial gradient in metallicity and age across nearly all locations of the disk. The age and metallicity distribution functions shift from negatively skewed in the inner Galaxy to positively skewed at large radius. Significant bimodality in the [Mg/Fe]-[Fe/H] plane and in the [Mg/Fe]-age relation persist across the entire disk. The age estimates have typical uncertainties of similar to 0.15 in log(age) and may be subject to additional systematic errors, which impose limitations on conclusions drawn from this sample. Nevertheless, these results act as critical constraints on galactic evolution models, constraining which physical processes played a dominant role in the formation of the Milky Way disk. We discuss how radial migration predicts many of the observed trends near the solar neighborhood and in the outer disk, but an additional more dramatic evolution history, such as the multi-infall model or a merger event, is needed to explain the chemical and age bimodality elsewhere in the Galaxy.
8.	Poyatos, R., et al. (författare) Global transpiration data from sap flow measurements: the SAPFLUXNET database 2021 Ingår i: Earth System Science Data. - : Copernicus GmbH. - 1866-3508 .- 1866-3516. ; 13:6, s. 2607-2649 Tidskriftsartikel (refereegranskat)abstract Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land-atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The "sapfluxnetr" R package - designed to access, visualize, and process SAPFLUXNET data - is available from CRAN.
9.	Weinberg, David H., et al. (författare) Chemical Cartography with APOGEE : Multi-element Abundance Ratios 2019 Ingår i: Astrophysical Journal. - : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 874:1 Tidskriftsartikel (refereegranskat)abstract We map the trends of elemental abundance ratios across the Galactic disk, spanning R = 3-15 kpc and midplane distance vertical bar Z vertical bar = 0-2 kpc, for 15 elements in a sample of 20,485 stars measured by the SDSS/APOGEE survey (O, Na, Mg, Al, Si, P, S, K, Ca, V, Cr, Mn, Fe, Co, Ni). Adopting Mg rather than Fe as our reference element, and separating stars into two populations based on [Fe/Mg], we find that the median trends of [X/Mg] versus [Mg/H] in each population are nearly independent of location in the Galaxy. The full multi-element cartography can be summarized by combining these nearly universal median sequences with our measured metallicity distribution functions and the relative proportions of the low-[Fe/Mg] (high-alpha) and high-[Fe/Mg] (low-alpha) populations, which depend strongly on R and vertical bar Z vertical bar. We interpret the median sequences with a semi-empirical "two-process" model that describes both the ratio of core collapse and Type Ia supernova (SN Ia) contributions to each element and the metallicity dependence of the supernova yields. These observationally inferred trends can provide strong tests of supernova nucleosynthesis calculations. Our results lead to a relatively simple picture of abundance ratio variations in the Milky Way, in which the trends at any location can be described as the sum of two components with relative contributions that change systematically and smoothly across the Galaxy. Deviations from this picture and future extensions to other elements can provide further insights into the physics of stellar nucleosynthesis and unusual events in the Galaxy's history.
10.	Bruhner, Carl Magnus, 1988-, et al. (författare) Bridging the Privacy Gap: Enhanced User Consent Mechanisms on the Web 2023 Ingår i: Proc. NDSS Workshop on Measurements, Attacks, and Defenses for the Web (MADWeb @NDSS). - Reston, VA : Internet Society. - 1891562878 Konferensbidrag (refereegranskat)abstract In the age of the General Data Protection Regula-tion (GDPR) and the California Consumer Privacy Act (CCPA),privacy and consent control have become even more apparent forevery-day web users. Privacy banners in all shapes and sizes askfor permission through more or less challenging designs and makeprivacy control more of a struggle than they help users’ privacy.In this paper, we present a novel solution expanding the AdvancedData Protection Control (ADPC) mechanism to bridge currentgaps in user data and privacy control. Our solution moves theconsent control to the browser interface to give users a seamlessand hassle-free experience, while at the same time offering contentproviders a way to be legally compliant with legislation. Throughan extensive review, we evaluate previous works and identifycurrent gaps in user data control. We then present a blueprintfor future implementation and suggest features to support privacycontrol online for users globally. Given browser support, thesolution provides a tangible path to effectively achieve legallycompliant privacy and consent control in a user-oriented mannerthat could allow them to again browse the web seamlessly.
11.	Cunha, Katia, et al. (författare) Adding the s-Process Element Cerium to the APOGEE Survey : Identification and Characterization of Ce II Lines in the H-band Spectral Window 2017 Ingår i: Astrophysical Journal. - : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 844:2 Tidskriftsartikel (refereegranskat)abstract Nine Ce II lines have been identified and characterized within the spectral window observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey (between lambda 1.51 and 1.69 mu m). At solar metallicities, cerium is an element that is produced predominantly as a result of the slow capture of neutrons (the s-process) during asymptotic giant branch stellar evolution. The Ce II lines were identified using a combination of a high-resolution (R = lambda/delta lambda = 100,000) Fourier Transform Spectrometer (FTS) spectrum of a Boo and an APOGEE spectrum (R. =. 22,400) of a metal-poor, but s-process enriched, red giant (2M16011638-1201525). Laboratory oscillator strengths are not available for these lines. Astrophysical gf-values were derived using alpha Boo as a standard star, with the absolute cerium abundance in alpha Boo set by using optical Ce II lines that have precise published laboratory gf-values. The near-infrared Ce II lines identified here are also analyzed, as consistency checks, in a small number of bright red giants using archival FTS spectra, as well as a small sample of APOGEE red giants, including two members of the open cluster NGC 6819, two field stars, and seven metal-poor N-and Al-rich stars. The conclusion is that this set of Ce II lines can be detected and analyzed in a large fraction of the APOGEE red giant sample and will be useful for probing chemical evolution of the s-process products in various populations of the Milky Way.
12.	Gómez-Blanco, David, et al. (författare) Why and when should organisms elongate their telomeres? : Elaborations on the 'excess resources elongation' and 'last resort elongation' hypotheses 2023 Ingår i: Ecology and Evolution. - 2045-7758. ; 13:12 Tidskriftsartikel (refereegranskat)abstract Telomere length and telomere shortening are thought to be critical cellular attributes and processes that are related to an individual's life span and fitness. The general pattern across most taxa is that after birth telomere length gradually decreases with age. Telomere protection and restoration mechanisms are usually assumed to reduce the rate of shortening or at most keep telomere length constant. However, here we have compiled a list of 26 articles showing that there is an increasing number of studies reporting apparent elongation of telomeres (i.e., a net increase in TL from time t to time t+1 ) often in a considerable proportion of the individuals studied. Moreover, the few studies which have studied telomere elongation in detail show that increases in telomere length are unlikely to be due to measurement error alone. In this article, we argue that episodes of telomere elongation deserve more attention as they could reflect individual strategies to optimise life histories and maximise fitness, which may not be reflected in the overall telomere dynamics patterns. We propose that patterns of telomere (net) elongation may be partly determined by other factors than those causing telomere shortening, and therefore deserve analyses specifically targeted to investigate the occurrence of telomere elongation. We elaborate on two ecological hypotheses that have been proposed to explain patterns of telomere elongation (the 'excess resources elongation' and the 'last resort elongation' hypothesis) and we discuss the current evidence for (or against) these hypotheses and propose ways to test them.
13.	Hasselquist, David, et al. (författare) Hypothesis-based Comparison of IPv6 and IPv4 Path Distances 2020 Ingår i: Symposium on Modelling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS). - Cham : Springer. - 9783030681098 - 9783030681104 Konferensbidrag (refereegranskat)abstract Short end-to-end path lengths and faster round-trip times (RTTs) are important for good client performance. While prior measurement studies related to IPv6 primarily focus on various adoption aspects, much less work have focused on performance metrics such as these. In this paper, we compare the relative end-to-end path distances and RTTs when using IPv6 and IPv4 between PlanetLab nodes in Europe and different subsets of popular domains. In addition to providing access to multiple measurement nodes, the use of PlanetLab also provides a use-case driven report of running IPv6 experiments on this previously prosperous experimental platform for academic research. In particular, the study provides a first report on performing IPv6 experiments on PlanetLab, highlights the lack of IP support among PlanetLab nodes and limitations of state-of-the-art traceroute tools used for IPv6 measurements, and provides a statistical methodology that uses hypothesis testing to derive insights while accounting for such testbed and traceroute shortcomings. Our performance analysis shows (among other things) that the relative RTTs of the IPv6 paths are currently faster than the corresponding IPv4 paths, and that the fraction of pairings for which this is the case is quickly increasing across a wide range of domain popularities and domain categories. These findings suggest that there is incentive to use IPv6, which may impact the rate of further IPv6 deployment.
14.	Hasselquist, David, et al. (författare) Lightweight Fingerprint Attack and Encrypted Traffic Analysis on News Articles 2022 Ingår i: <em></em>2022 IFIP Networking Conference (IFIP Networking). - : IEEE. - 9783903176485 Konferensbidrag (refereegranskat)abstract The news articles we read online can reveal a lot about us. Privacy aware groups have therefore long pushed for the use of HTTPS (encrypted end-to-end communication). In this paper, we present the design and evaluation of a lightweight framework that can (1) successfully identify individual news articles even when the articles are delivered over encrypted connections, and (2) separate between articles associated with different news websites even when the websites are delivered over the same infrastructure. Our results demonstrate that naive use of HTTPS is not enough to prevent attackers monitoring a user's connections from identifying articles that the user reads on the most popular news website. We also provide insights into what makes some websites more/less resilient to our attack, and we use Twitter data to evaluate the effectiveness of an example attack that in addition incorporates the popularity of individual news articles. We are the first to demonstrate and evaluate the practical effectiveness of this type of attack when applied on modern news websites, and our multi-website-based evaluation provides valuable insights into how websites can best protect themselves against this type of attacks. These insights are important for websites that want to help protect the privacy of their users.
15.	Hasselquist, David, et al. (författare) Longitudinal Analysis of Wildcard Certificates in the WebPKI 2023 Ingår i: 2023 IFIP NETWORKING CONFERENCE, IFIP NETWORKING. - : IEEE. - 9783903176577 - 9798350339383 Konferensbidrag (refereegranskat)abstract The use of wildcard certificates and multi-domain certificates can impact how sensitive a certificate is to attacks and how many (sub)domains and machines may be impacted if a private key is compromised. Unfortunately, there are no globally agreed-upon best practices for these certificate types and the recommendations have changed many times over the years. In this paper, we present a 10-year longitudinal analysis of the usage of wildcard certificates and multi-domain certificates on the internet. Our analysis captures and highlights substantial differences in the heterogenous wildcard and multi-domain certificate practices. The results also show that there are several ways that CAs and domain owners have chosen to improve their practices, with many appearing to reduce the number of domains (and subdomains) for which each certificate is responsible.
16.	Hasselquist, David, et al. (författare) Now is the Time: Scalable and Cloud-supported Audio Conferencing using End-to-End Homomorphic Encryption 2023 Ingår i: PROCEEDINGS OF THE 2023 CLOUD COMPUTING SECURITY WORKSHOP, CCSW 2023. - : ASSOC COMPUTING MACHINERY. - 9798400702594 ; , s. 41-53 Konferensbidrag (refereegranskat)abstract Homomorphic encryption (HE) allows computations on encrypted data, leaking neither the input nor the computational output. While the method has historically been infeasible to use in practice, due to recent advancements, HE has started to be applied in real-world applications. Motivated by the possibility of outsourcing heavy computations to the cloud and still maintaining end-to-end security, in this paper, we use HE to design a basic audio conferencing application and demonstrate that our design approach (including some advanced features) is both practical and scalable. First, by homomorphically mixing encrypted audio in an untrusted, honest-but-curious server, we demonstrate the practical use of HE in audio communication. Second, by using multiplication operations, we go beyond the purely additive audio mixing and implement advanced example features capable of handling server-side mute and breakout rooms without the cloud server being able to extract sensitive user-specific metadata. Whereas the encryption and decryption times are shown to be magnitudes slower than generic AES encryption and roughly ten times slower than Signal's AES implementation, our solution approach is scalable and achieves end-to-end encryption while keeping performance well within the bounds of practical use. Third, besides studying the performance aspects, we also objectively evaluate the perceived audio quality, demonstrating that this approach also achieves excellent audio quality. Finally, our comprehensive evaluation and empirical findings provide valuable insights into the tradeoffs between HE schemes, their security configurations, and audio parameters. Combined, our results demonstrate that audio mixing using HE (including advanced features) now can be made both practical and scalable.
17.	Hasselquist, David, et al. (författare) PET-Exchange: A Privacy Enhanced Trading Exchange using Homomorphic Encryption 2023 Ingår i: 2023 20TH ANNUAL INTERNATIONAL CONFERENCE ON PRIVACY, SECURITY AND TRUST, PST. - : IEEE. - 9798350313871 - 9798350313888 ; , s. 168-179 Konferensbidrag (refereegranskat)abstract The underlying trading mechanisms of electronic securities exchanges have mostly stayed the same over the years with some additions and improvements. However, over the recent decade, high-frequency traders using algorithmic trading have shifted the field using practices that many consider unfair or unethical. In addition, insider trading continues to cause trust issues on certain trading platforms. In this paper, we present PET-Exchange, a privacy-preserving framework for trading securities on an electronic stock exchange. By using homomorphic encryption, PET-Exchange prevents information disclosures and unfair advantages in the trading processes. By matching and trading encrypted orders, we study the performance under various volumes and timing constraints, and compare this to the unencrypted counterparts. Our analysis of PET-Exchange using market trade data shows the privacy and cryptographic tradeoffs, demonstrating it to be suitable for small-scale trading and privacy-preserving auctions. Finally, we discuss the potential impact on transparency, fairness, and opportunities for financial crime in an electronic securities exchange. The insights we provide take us one step closer to a privacy-aware and fair public securities exchange.
18.	Hasselquist, David, et al. (författare) Phishing in Style: Characterizing Phishing Websites in the Wild 2023 Ingår i: Proc. Network Traffic Measurement and Analysis Conference (TMA). - : Institute of Electrical and Electronics Engineers (IEEE). - 9783903176584 - 9798350325676 Konferensbidrag (refereegranskat)abstract The prevalence of phishing domains is steadily rising as attackers exploit toolkits to create phishing websites. As web development expertise is no longer a prerequisite, phishing attacks have become more widespread, outpacing many existing detection methods. Developing novel techniques to identify malicious domains is crucial to safeguard potential victims online. While most current methods emphasize the visual aspects of phishing websites, in this paper, we investigate the underlying structure by collecting data on style sheets and certificates from both verified phishing domains and benign domains. Using a token-based similarity algorithm, we group the phishing domains into three categories and identify shared characteristics of these domains. Our work demonstrates the feasibility of using structural similarities to identify a website created using a phishing kit. By employing such detection, users would be able to browse the web with a reduced risk of falling victim to malicious activities.
19.	Hasselquist, David, et al. (författare) QUIC Throughput and Fairness over Dual Connectivity 2020 Ingår i: Symposium on Modelling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS). - Cham : Springer. - 9783030681098 - 9783030681104 Konferensbidrag (refereegranskat)abstract Dual Connectivity (DC) is an important lower-layer feature accelerating the transition from 4G to 5G that also is expected to play an important role in standalone 5G. However, even though the packet reordering introduced by DC can significantly impact the performance of upper-layer protocols, no prior work has studied the impact of DC on QUIC. In this paper, we present the first such performance study. Using a series of throughput and fairness experiments, we show how QUIC is affected by different DC parameters, network conditions, and whether the DC implementation aims to improve throughput or reliability. Our findings provide insights into the impacts of splitting QUIC traffic in a DC environment. With reasonably selected DC parameters and increased UDP receive buffers, QUIC over DC performs similarly to TCP over DC and achieves optimal fairness under symmetric link conditions when DC is not used for packet duplication.
20.	Hasselquist, David, et al. (författare) QUIC Throughput and Fairness over Dual Connectivity 2022 Ingår i: Computer Networks. - : ELSEVIER. - 1389-1286 .- 1872-7069. ; 219 Tidskriftsartikel (refereegranskat)abstract Dual Connectivity (DC) is an important lower-layer feature accelerating the transition from 4G to 5G that also is expected to play an important role in standalone 5G radio networks. However, even though the packet reordering introduced by DC can significantly impact the performance of upper-layer protocols, no prior work has studied the impact of DC on QUIC. In this paper, we present the first such performance study. Using a series of throughput and fairness experiments, we show how QUIC is affected by different DC parameters, network conditions, and whether the DC implementation aims to improve throughput or reliability. Results for two QUIC implementations (aioquic, ngtcp2) and two congestion control algorithms (NewReno, CUBIC) are presented under both static and highly time-varying network conditions Our findings provide network operators with insights and understanding into the impacts of splitting QUIC traffic in a DC environment. With reasonably selected DC parameters and increased UDP receive buffers, QUIC over DC performs similarly to TCP over DC and achieves optimal fairness under symmetric link conditions when DC is not used for packet duplication. The insights can help network operators provide modern users with better end-to-end service when deploying DC.
21.	Hasselquist, David, et al. (författare) Trends and Detection Avoidance of Internet-Connected Industrial Control Systems 2019 Ingår i: IEEE Access. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2169-3536. ; 7, s. 155504-155512 Tidskriftsartikel (refereegranskat)abstract The search engine Shodan crawls the Internet for, among other things, Industrial Control Systems (ICS). ICS are devices used to operate and automate industrial processes. Due to the increasing popularity of the Internet, these devices are getting more and more connected to the Internet. These devices will, if not hidden, be shown on Shodan. This study uses Shodan, together with data found by other researches to plot the trends of these ICS devices. The studied trends focus on the country percentage distribution and the usage of ICS protocols. The results show that all studied countries, except the United States, have decreased their percentage of world total ICS devices. We suspect that this does not represent the real story, as companies are getting better at hiding their devices from online crawlers. Our results also show that the usage of old ICS protocols is increasing. One of the explanations is that industrial devices, running old communication protocols, are increasingly getting connected to the Internet. In addition to the trend study, we evaluate Shodan by studying the time it takes for Shodan to index one of our devices on several networks. We also study ways of avoiding detection by Shodan and show that, by using a method called port knocking, it is relatively easy for a device to hide from Shodan, but remain accessible for legitimate users.
22.	Hasselquist, David, et al. (författare) Twitch Chat Fingerprinting 2022 Ingår i: Proc. IFIP Network Traffic Measurement and Analysis Conference (TMA) 2022. Konferensbidrag (refereegranskat)abstract The streaming content that we choose to watch canreveal much about our thoughts, opinions, and interests. Anadversary capable of determining what users watch thereforepresents a significant privacy threat. In this paper, we presentand evaluate the first fingerprinting attack on Twitch that allowsviewers of individual live streams to be identified despite thetraffic being encrypted. The attack targets the traffic patternsassociated with chat messages associated with each stream. Ourresults show that high accuracy can be achieved by eavesdroppingonly for a short time (e.g., 90 seconds) and that the accuracy canbe increased even further by interacting with the stream. We alsotake a closer look at how the accuracy and activity level differbetween different Twitch channels and provide insights into theaccuracy that attackers using different strategies for selectingtarget channels may have. Finally, we study countermeasures toprotect against such attacks and demonstrate that the naive use ofVPN is not enough. We instead present countermeasures alteringpacket timing and sizes. Our large-scale evaluation of differentcountermeasures provides important insights that help both thestreaming providers and users better protect their privacy.
23.	Hasselquist, Sten, et al. (författare) Exploring the stellar age distribution of the milky way bulge using APOGEE 2020 Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 901:2 Tidskriftsartikel (refereegranskat)abstract We present stellar age distributions of the Milky Way bulge region using ages for ∼6000 high-luminosity (log(g)< 2.0), metal-rich ([Fe/H] ≥ -0.5) bulge stars observed by the Apache Point Observatory Galactic Evolution Experiment. Ages are derived using The Cannon label-transfer method, trained on a sample of nearby luminous giants with precise parallaxes for which we obtain ages using a Bayesian isochrone-matching technique. We find that the metal-rich bulge is predominantly composed of old stars (>8 Gyr). We find evidence that the planar region of the bulge (ZGC\| 0.25 kpc) is enriched in metallicity, Z, at a faster rate (dZ/dt ∼ 0.0034 Gyr-1) than regions farther from the plane (dZ/dt ∼ 0.0013 Gyr-1 at \| ZGC\| > 1.00 kpc). We identify a nonnegligible fraction of younger stars (age ∼2-5 Gyr) at metallicities of +0.2 < [Fe/H] < +0.4. These stars are preferentially found in the plane (ZGC\| ≤ 0.25 kpc) and at R cy ≈ 2-3 kpc, with kinematics that are more consistent with rotation than are the kinematics of older stars at the same metallicities. We do not measure a significant age difference between stars found inside and outside the bar. These findings show that the bulge experienced an initial starburst that was more intense close to the plane than far from the plane. Then, star formation continued at supersolar metallicities in a thin disk at 2 kpc ≲ R cy ≲ 3 kpc until ∼2 Gyr ago.
24.	Horta, Danny, et al. (författare) The chemical characterization of halo substructure in the Milky Way based on APOGEE 2023 Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 520:4, s. 5671-5711 Tidskriftsartikel (refereegranskat)abstract Galactic haloes in a Λ-CDM universe are predicted to host today a swarm of debris resulting from cannibalized dwarf galaxies. The chemodynamical information recorded in their stellar populations helps elucidate their nature, constraining the assembly history of the Galaxy. Using data from APOGEE and Gaia, we examine the chemical properties of various halo substructures, considering elements that sample various nucleosynthetic pathways. The systems studied are Heracles, Gaia-Enceladus/Sausage (GES), the Helmi stream, Sequoia, Thamnos, Aleph, LMS-1, Arjuna, I’itoi, Nyx, Icarus, and Pontus. Abundance patterns of all substructures are cross-compared in a statistically robust fashion. Our main findings include: (i) the chemical properties of most substructures studied match qualitatively those of dwarf Milky Way satellites, such as the Sagittarius dSph. Exceptions are Nyx and Aleph, which are chemically similar to disc stars, implying that these substructures were likely formed in situ; (ii) Heracles differs chemically from in situ populations such as Aurora and its inner halo counterparts in a statistically significant way. The differences suggest that the star formation rate was lower in Heracles than in the early Milky Way; (iii) the chemistry of Arjuna, LMS-1, and I’itoi is indistinguishable from that of GES, suggesting a possible common origin; (iv) all three Sequoia samples studied are qualitatively similar. However, only two of those samples present chemistry that is consistent with GES in a statistically significant fashion; (v) the abundance patterns of the Helmi stream and Thamnos are different from all other halo substructures.
25.	Horta, Danny, et al. (författare) The chemical compositions of accreted and in situ galactic globular clusters according to SDSS/APOGEE 2020 Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966. ; 493:3, s. 3363-3378 Tidskriftsartikel (refereegranskat)abstract Studies of the kinematics and chemical compositions of Galactic globular clusters (GCs) enable the reconstruction of the history of star formation, chemical evolution, and mass assembly of the Galaxy. Using the latest data release (DR16) of the SDSS/APOGEE survey, we identify 3090 stars associated with 46 GCs. Using a previously defined kinematic association, we break the sample down into eight separate groups and examine how the kinematics-based classification maps into chemical composition space, considering only a (mostly Si and Mg) elements and Fe. Our results show that (i) the loci of both in situ and accreted subgroups in chemical space match those of their field counterparts; (ii) GCs from different individual accreted subgroups occupy the same locus in chemical space. This could either mean that they share a similar origin or that they are associated with distinct satelliteswhich underwent similar chemical enrichment histories; (iii) the chemical compositions of the GCs associated with the low orbital energy subgroup defined by Massari and collaborators is broadly consistent with an in situ origin. However, at the low-metallicity end, the distinction between accreted and in situ populations is blurred; (iv) regarding the status of GCs whose origin is ambiguous, we conclude the following: the position in Si-Fe plane suggests an in situ origin for Liller 1 and a likely accreted origin for NGC 5904 and NGC 6388. The case of NGC 288 is unclear, as its orbital properties suggest an accretion origin, its chemical composition suggests it may have formed in situ.
26.	Kuglerova, Lenka, et al. (författare) Management perspectives on Aqua incognita : Connectivity and cumulative effects of small natural and artificial streams in boreal forests 2017 Ingår i: Hydrological Processes. - : WILEY. - 0885-6087 .- 1099-1085. ; 31:23, s. 4238-4244 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
27.	Metcalfe, Daniel B., et al. (författare) Patchy field sampling biases understanding of climate change impacts across the Arctic 2018 Ingår i: Nature Ecology and Evolution. - : Springer Science and Business Media LLC. - 2397-334X. ; 2:9, s. 1443-1448 Tidskriftsartikel (refereegranskat)abstract Effective societal responses to rapid climate change in the Arctic rely on an accurate representation of region-specific ecosystem properties and processes. However, this is limited by the scarcity and patchy distribution of field measurements. Here, we use a comprehensive, geo-referenced database of primary field measurements in 1,840 published studies across the Arctic to identify statistically significant spatial biases in field sampling and study citation across this globally important region. We find that 31% of all study citations are derived from sites located within 50 km of just two research sites: Toolik Lake in the USA and Abisko in Sweden. Furthermore, relatively colder, more rapidly warming and sparsely vegetated sites are under-sampled and under-recognized in terms of citations, particularly among microbiology-related studies. The poorly sampled and cited areas, mainly in the Canadian high-Arctic archipelago and the Arctic coastline of Russia, constitute a large fraction of the Arctic ice-free land area. Our results suggest that the current pattern of sampling and citation may bias the scientific consensuses that underpin attempts to accurately predict and effectively mitigate climate change in the region. Further work is required to increase both the quality and quantity of sampling, and incorporate existing literature from poorly cited areas to generate a more representative picture of Arctic climate change and its environmental impacts.
28.	Naurin, Sara, et al. (författare) A microarray for large-scale genomic and transcriptional analyses of the zebra finch (Taeniopygia guttata) and other passerines 2008 Ingår i: Molecular Ecology Notes. - : Wiley. - 1471-8278 .- 1755-098X. ; 8:2, s. 275-281 Tidskriftsartikel (refereegranskat)abstract The microarray technology has revolutionized biological research in the last decade. By monitoring the expression of many genes simultaneously, microarrays can elucidate gene function, as well as scan entire genomes for candidate genes encoding complex traits. However, because of high costs of sequencing and design, microarrays have largely been restricted to a few model species. Cross-species microarray (CSM) analyses, where microarrays are used for other species than the one they were designed for, have had varied success. We have conducted a CSM analysis by hybridizing genomic DNA from the common whitethroat (Sylvia communis) on a newly developed Affymetrix array designed for the zebra finch (Taeniopygia guttata), the Lund-zf array. The results indicate a very high potential for the zebra finch array to act as a CSM utility in other passerine birds. When hybridizing zebra finch genomic DNA, 98% of the gene representatives had higher signal intensities than the background cut-off, and for the common whitethroat, we found the equivalent proportion to be as high as 96%. This was surprising given the fact that finches and warblers diverged 25-50 million years ago, but may be explained by a relatively low sequence divergence between passerines (89-93%). Passerine birds are widely used in studies of ecology and evolution, and a zebra finch array that can be used for many species may have a large impact on future research directions.
29.	Nidever, David L., et al. (författare) The Lazy Giants : APOGEE Abundances Reveal Low Star Formation Efficiencies in the Magellanic Clouds 2020 Ingår i: Astrophysical Journal. - : Institute of Physics (IOP). - 0004-637X .- 1538-4357. ; 895:2 Tidskriftsartikel (refereegranskat)abstract We report the first APOGEE metallicities and alpha-element abundances measured for 3600 red giant stars spanning a large radial range of both the Large (LMC) and Small Magellanic Clouds, the largest Milky Way (MW) dwarf galaxies. Our sample is an order of magnitude larger than that of previous studies and extends to much larger radial distances. These are the first results presented that make use of the newly installed southern APOGEE instrument on the du Pont telescope at Las Campanas Observatory. Our unbiased sample of the LMC spans a large range in metallicity, from [Fe/H] = -0.2 to very metal-poor stars with [Fe/H] -2.5, the most metal-poor Magellanic Cloud (MC) stars detected to date. The LMC [alpha/Fe]-[Fe/H] distribution is very flat over a large metallicity range but rises by similar to 0.1 dex at -1.0 < [Fe/H] less than or similar to -0.5. We interpret this as a sign of the known recent increase in MC star formation activity and are able to reproduce the pattern with a chemical evolution model that includes a recent "starburst." At the metal-poor end, we capture the increase of [alpha/Fe] with decreasing [Fe/H] and constrain the "alpha-knee" to [Fe/H] less than or similar to -2.2 in both MCs, implying a low star formation efficiency of similar to 0.01 Gyr(-1). The MC knees are more metal-poor than those of less massive MW dwarf galaxies such as Fornax, Sculptor, or Sagittarius. One possible interpretation is that the MCs formed in a lower-density environment than the MW, a hypothesis that is consistent with the paradigm that the MCs fell into the MW's gravitational potential only recently.
30.	Palacios, Maria G., et al. (författare) Consequences of immune system aging in nature: a study of immunosenescence costs in free-living Tree Swallows 2011 Ingår i: Ecology. - : Wiley. - 0012-9658. ; 92:4, s. 952-966 Tidskriftsartikel (refereegranskat)abstract Immunosenescence, the aging of the immune system, is well documented in humans and laboratory models and is known to increase infection risk, morbidity, and mortality among the old. Immunosenescence patterns have recently been unveiled in various free-living populations, but their consequences in the wild have not been explored. We investigated the consequences of immunosenescence in free-living Tree Swallows Tachycineta bicolor through a field experiment simulating a bacterial infection (challenge with lipopolysaccharide, LPS) in females of different ages during the nestling rearing period. We assessed behavioral and physiological responses of females, as well as growth and quality of their offspring, to determine the costs associated with the simulated infection. Results of the experiment differed between the two years of study. In the first year, old females challenged with LPS lost more body mass and reduced their nest visitation rates more, and their offspring tended to grow slower compared to similarly challenged younger females. In contrast, in the second year, old females did not appear to suffer larger costs than younger ones. Interestingly, immunosenescence was only detected during the first year of the study, suggesting that it is the dysregulated immune function characteristic of immunosenescent individuals rather than age per se that can lead to higher costs of immune defense in old individuals. These results provide the first evidence of costs of immunosenescence in free-living animals and support the hypothesis that old, immunosenescent individuals pay higher costs than younger ones when faced with a challenge to their immune system. Our results also suggest that these costs are mediated by an exaggerated sickness behavior, as seen in laboratory models, and can be modulated by ecological factors such as weather conditions and food availability.
31.	Radchuk, Viktoriia, et al. (författare) Adaptive responses of animals to climate change are most likely insufficient 2019 Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1 Tidskriftsartikel (refereegranskat)abstract Biological responses to climate change have been widely documented across taxa and regions, but it remains unclear whether species are maintaining a good match between phenotype and environment, i.e. whether observed trait changes are adaptive. Here we reviewed 10,090 abstracts and extracted data from 71 studies reported in 58 relevant publications, to assess quantitatively whether phenotypic trait changes associated with climate change are adaptive in animals. A meta-analysis focussing on birds, the taxon best represented in our dataset, suggests that global warming has not systematically affected morphological traits, but has advanced phenological traits. We demonstrate that these advances are adaptive for some species, but imperfect as evidenced by the observed consistent selection for earlier timing. Application of a theoretical model indicates that the evolutionary load imposed by incomplete adaptive responses to ongoing climate change may already be threatening the persistence of species.
32.	Replogle, Kirstin, et al. (författare) The Songbird Neurogenomics (SoNG) Initiative: Community-based tools and strategies for study of brain gene function and evolution 2008 Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 9:131 Tidskriftsartikel (refereegranskat)abstract Background: Songbirds hold great promise for biomedical, environmental and evolutionary research. A complete draft sequence of the zebra finch genome is imminent, yet a need remains for application of genomic resources within a research community traditionally focused on ethology and neurobiological methods. In response, we developed a core set of genomic tools and a novel collaborative strategy to probe gene expression in diverse songbird species and natural contexts. Results: We end-sequenced cDNAs from zebra finch brain and incorporated additional sequences from community sources into a database of 86,784 high quality reads. These assembled into 31,658 non-redundant contigs and singletons, which we annotated via BLAST search of chicken and human databases. The results are publicly available in the ESTIMA: Songbird database. We produced a spotted cDNA microarray with 20,160 addresses representing 17,214 non-redundant products of an estimated 11,500-15,000 genes, validating it by analysis of immediate-early gene (zenk) gene activation following song exposure and by demonstrating effective cross hybridization to genomic DNAs of other songbird species in the Passerida Parvorder. Our assembly was also used in the design of the "Lund-zfa" Affymetrix array representing similar to 22,000 non-redundant sequences. When the two arrays were hybridized to cDNAs from the same set of male and female zebra finch brain samples, both arrays detected a common set of regulated transcripts with a Pearson correlation coefficient of 0.895. To stimulate use of these resources by the songbird research community and to maintain consistent technical standards, we devised a "Community Collaboration" mechanism whereby individual birdsong researchers develop experiments and provide tissues, but a single individual in the community is responsible for all RNA extractions, labelling and microarray hybridizations. Conclusion: Immediately, these results set the foundation for a coordinated set of 25 planned experiments by 16 research groups probing fundamental links between genome, brain, evolution and behavior in songbirds. Energetic application of genomic resources to research using songbirds should help illuminate how complex neural and behavioral traits emerge and evolve.
33.	Rosenquist, Hampus, et al. (författare) On the Dark Side of the Coin: Characterizing Bitcoin Use for Illicit Activities 2024 Ingår i: PASSIVE AND ACTIVE MEASUREMENT, PAM 2024, PT II. - : SPRINGER INTERNATIONAL PUBLISHING AG. - 9783031562518 - 9783031562525 ; , s. 37-66 Konferensbidrag (refereegranskat)abstract The decentralized nature of Bitcoin allows for pseudonymous money exchange beyond authorities' control, contributing to its popularity for diverse illegal activities such as scams, ransomware attacks, money laundering, and black markets. In this paper, we characterize this landscape, providing insights into similarities and differences in the use of Bitcoin for such activities. Our analysis and the derived insights contribute to the understanding of Bitcoin transactions associated with illegal activities through three main aspects. First, our study offers a comprehensive characterization of money flows to and from Bitcoin addresses linked to different abuse categories, revealing variations in flow patterns and success rates. Second, our temporal analysis captures long-term trends and weekly patterns across categories. Finally, our analysis of outflow from reported addresses uncovers differences in graph properties and flow patterns among illicit addresses and between abuse categories. These findings provide valuable insights into the distribution, temporal dynamics, and interconnections within various categories of Bitcoin transactions related to illicit activities. The increased understanding of this landscape and the insights gained from this study offer important empirical guidance for informed decision-making and policy development in the ongoing effort to address the challenges presented by illicit activities within the cryptocurrency space.
34.	Santana, Felipe A., et al. (författare) Final Targeting Strategy for the SDSS-IV APOGEE-2S Survey 2021 Ingår i: Astronomical Journal. - : American Astronomical Society. - 1538-3881 .- 0004-6256. ; 162:6 Tidskriftsartikel (refereegranskat)abstract APOGEE is a high-resolution (R similar to 22,000), near-infrared, multi-epoch, spectroscopic survey of the Milky Way. The second generation of the APOGEE project, APOGEE-2, includes an expansion of the survey to the Southern Hemisphere called APOGEE-2S. This expansion enabled APOGEE to perform a fully panoramic mapping of all of the main regions of the Milky Way; in particular, by operating in the H band, APOGEE is uniquely able to probe the dust-hidden inner regions of the Milky Way that are best accessed from the Southern Hemisphere. In this paper we present the targeting strategy of APOGEE-2S, with special attention to documenting modifications to the original, previously published plan. The motivation for these changes is explained as well as an assessment of their effectiveness in achieving their intended scientific objective. In anticipation of this being the last paper detailing APOGEE targeting, we present an accounting of all such information complete through the end of the APOGEE-2S project; this includes several main survey programs dedicated to exploration of major stellar populations and regions of the Milky Way, as well as a full list of programs contributing to the APOGEE database through allocations of observing time by the Chilean National Time Allocation Committee and the Carnegie Institution for Science. This work was presented along with a companion article, Beaton et al. (2021), presenting the final target selection strategy adopted for APOGEE-2 in the Northern Hemisphere.
35.	Tobler, Michael, et al. (författare) Telomeres in ecology and evolution : A review and classification of hypotheses 2022 Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 31:23, s. 5946-5965 Forskningsöversikt (refereegranskat)abstract Research on telomeres in the fields of ecology and evolution has been rapidly expanding over the last two decades. This has resulted in the formulation of a multitude of, often name-given, hypotheses related to the associations between telomeres and life-history traits or fitness-facilitating processes (and the mechanisms underlying them). However, the differences (or similarities) between the various hypotheses, which can originate from different research fields, are often not obvious. Our aim here is therefore to give an overview of the hypotheses that are of interest in ecology and evolution and to provide two frameworks that help discriminate among them. We group the hypotheses (i) based on their association with different research questions, and (ii) using a hierarchical approach that builds on the assumptions they make, such as about causality of telomere length/shortening and/or the proposed functional consequences of telomere shortening on organism performance. Both our frameworks show that there exist parallel lines of thoughts in different research fields. Moreover, they also clearly illustrate that there are in many cases competing hypotheses within clusters, and that some of these even have contradictory assumptions and/or predictions. We also touch upon two topics in telomere research that would benefit from further conceptualization. This review should help researchers, both those familiar with and those new to the subject, to identify future avenues of research.
36.	Weinberg, David H., et al. (författare) Chemical Cartography with APOGEE : Mapping Disk Populations with a 2-process Model and Residual Abundances 2022 Ingår i: Astrophysical Journal Supplement Series. - : IOP Publishing Ltd. - 0067-0049 .- 1538-4365. ; 260:2, s. 1-46 Tidskriftsartikel (refereegranskat)abstract We apply a novel statistical analysis to measurements of 16 elemental abundances in 34,410 Milky Way disk stars from the final data release (DR17) of APOGEE-2. Building on recent work, we fit median abundance ratio trends [X/Mg] versus [Mg/H] with a 2-process model, which decomposes abundance patterns into a "prompt" component tracing core-collapse supernovae and a "delayed" component tracing Type Ia supernovae. For each sample star, we fit the amplitudes of these two components, then compute the residuals Delta[X/H] from this two-parameter fit. The rms residuals range from similar to 0.01-0.03 dex for the most precisely measured APOGEE abundances to similar to 0.1 dex for Na, V, and Ce. The correlations of residuals reveal a complex underlying structure, including a correlated element group comprised of Ca, Na, Al, K, Cr, and Ce and a separate group comprised of Ni, V, Mn, and Co. Selecting stars poorly fit by the 2-process model reveals a rich variety of physical outliers and sometimes subtle measurement errors. Residual abundances allow for the comparison of populations controlled for differences in metallicity and [alpha/Fe]. Relative to the main disk (R = 3-13 kpc), we find nearly identical abundance patterns in the outer disk (R = 15-17 kpc), 0.05-0.2 dex depressions of multiple elements in LMC and Gaia Sausage/Enceladus stars, and wild deviations (0.4-1 dex) of multiple elements in omega Cen. The residual abundance analysis opens new opportunities for discovering chemically distinctive stars and stellar populations, for empirically constraining nucleosynthetic yields, and for testing chemical evolution models that include stochasticity in the production and redistribution of elements.

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