The General AntiParticle Spectrometer (GAPS) is an Antarctic balloon-borne detector designed to measure low-energy cosmic antinuclei (<0.25GeV/n), with a specific focus on antideuterons, as a ...distinctive signal from dark matter annihilation or decay in the Galactic halo. The instrument consists of a tracker, made up of ten planes of lithium-drifted Silicon Si(Li) detectors, surrounded by a plastic scintillator Time-of-Flight system. GAPS uses a novel particle identification method based on exotic atom capture and decay with the emission of pions, protons, and atomic X-rays from a common annihilation vertex.
An important ingredient for the antinuclei identification is the reconstruction of the “annihilation star” topology. A custom antinucleus annihilation reconstruction algorithm, called the “star-finding” algorithm, was developed to reconstruct the annihilation star fully, determining the annihilation vertex position and reconstructing the tracks of the primary and secondary charged particles. The reconstruction algorithm and its performances were studied on simulated data obtained with the Geant4-based GAPS simulation software, which fully reproduced the detector geometry. This custom algorithm was found to have better performance in the vertex resolution and reconstruction efficiency compared with a standard Hough-3D algorithm.
The General Antiparticle Spectrometer (GAPS) is an Antarctic balloon experiment designed for low-energy (0.1–0.3 GeV/n) cosmic antinuclei as signatures of dark matter annihilation or decay. GAPS is ...optimized to detect low-energy antideuterons, as well as to provide unprecedented sensitivity to low-energy antiprotons and antihelium nuclei. The novel GAPS antiparticle detection technique, based on the formation, decay, and annihilation of exotic atoms, provides greater identification power for these low-energy antinuclei than previous magnetic spectrometer experiments. This work reports the sensitivity of GAPS to detect antihelium-3 nuclei, based on full instrument simulation, event reconstruction, and realistic atmospheric influence simulations. The report of antihelium nuclei candidate events by AMS-02 has generated considerable interest in antihelium nuclei as probes of dark matter and other beyond the Standard Model theories. GAPS is in a unique position to detect or set upper limits on the cosmic antihelium nuclei flux in an energy range that is essentially free of astrophysical background. In three 35-day long-duration balloon flights, GAPS will be sensitive to an antihelium flux on the level of 1.3−1.2+4.5·10−6 m-2sr-1s-1(GeV/n)-1 (95% confidence level) in the energy range of 0.11–0.3 GeV/n, opening a new window on rare cosmic physics.
The General Antiparticle Spectrometer (GAPS) is an upcoming balloon mission to measure low-energy cosmic-ray antinuclei during at least three ∼35-day Antarctic flights. With its large geometric ...acceptance and novel exotic atom-based particle identification, GAPS will detect ∼500 cosmic antiprotons per flight and produce a precision cosmic antiproton spectrum in the kinetic energy range of ∼0.07−0.21GeV/n at the top of the atmosphere. With these high statistics extending to lower energies than any previous experiment, and with complementary sources of experimental uncertainty compared to traditional magnetic spectrometers, the GAPS antiproton measurement will be sensitive to dark matter, primordial black holes, and cosmic ray propagation. The antiproton measurement will also validate the GAPS antinucleus identification technique for the antideuteron and antihelium rare-event searches. This analysis demonstrates the GAPS sensitivity to cosmic-ray antiprotons using a full instrument simulation and event reconstruction, and including solar and atmospheric effects.
Summary
Little is known about the life‐history traits exhibited by burbot (Lota lota) throughout their circumpolar range. Monitoring burbot movements between lentic and lotic habits and collection of ...demographic data (length, age, sex, and maturity) were used to answer the following questions in the Torrey Creek drainage of west‐central Wyoming, USA: (a) is there plasticity in the life‐history traits of the burbot population, (b) do Trail Lake origin and Torrey Creek origin burbot interchange during the spawning period, and (c) is there a difference in growth and age at sexual maturity between burbot captured in Trail Lake and Torrey Creek? Results indicated that burbot in Trail Lake and Torrey Creek exhibit plasticity in their life history traits. Directional movement of PIT‐tagged burbot in Trail Lake and Torrey Creek was monitored nearly continuously by tandem stream‐width antennas. Thirty‐five percent of lentic‐origin burbot migrated upstream into Torrey Creek, and 11% of lotic‐origin burbot migrated downstream of the antennas near the Torrey Creek inlet to Trail Lake. Migratory activity of burbot was highest during the late winter and early spring at a time that coincided with spawning. Additionally, Torrey Creek‐origin burbot were smaller and younger than Trail Lake‐origin burbot. In addition to documenting migration, the sampling of small, sexually mature burbot in Torrey Creek suggests that stream‐resident burbot reach maturity earlier than adfluvial and lacustrine burbot in Trail Lake. Furthermore, high catch rates of age‐0 burbot indicate that Torrey Creek upstream from Trail Lake provides nursery habitat to the burbot population. Life history trait plasticity and spawning and nursery habitats documented in this study should be considered when selecting conservation actions for this unique burbot population.
Les rapports d'isotopes de strontium (sup.87Sr/sup.86Sr) dans les otolites constituent un outil bien etabli pour determiner les origines et motifs de deplacement des poissons. L'extraction d'otolites ...necessite toutefois de sacrifier les poissons, et quand il s'agit d'especes protegees ou en peril, il est preferable d'utiliser des echantillons non letaux comme des ecailles, epines ou rayons de nageoire. Contrairement aux otolites, qui sont principalement constitues d'aragonite, ces tissus sont faits d'apatite biologique. L'analyse par spectrometrie de masse a source a plasma inductif a collection d'ions multiples combinee a l'ablation par laser (LA-MC-ICP-MS) d'apatite biologique peut induire une interference significative sur la masse 87, produisant des mesures inexactes du sup.87Sr/sup.86Sr. Pour quantifier cette interference, nous avons applique l'analyse par LA-MC-ICP-MS a trois echantillons marins (otolite d'acoupa blanc (Atractoscion nobilis); rayon de nageoire pectorale d'esturgeon vert (Acipenser medirostris); dent de taupe du Pacifique (Lamna ditropis) et fi des otolites, ecailles et epines de dore jaune (Sander vitreus) d'eau douce). Les conditions instrumentales qui maximisent l'intensite des signaux produisaient des rapports sup.87Sr/sup.86Sr eleves dans les echantillons de bioapatite, associes a une interference polyatomique (sup.40Casup.31Psup.16O, sup.40Arsup.31Psup.16O). L'ajustement des conditions instrumentales afin de reduire les niveaux d'oxydes a elimine cette interference, produisant des rapports sup.87Sr/sup.86Sr exacts pour tous les echantillons de tissus. Cette methode constitue une solution de rechange originale et non letale a l'analyse des otolites pour reconstituer le cycle biologique des poissons. Traduit par la Redaction
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We examined the diets of age‐6 and age‐7 hatchery‐reared juvenile pallid sturgeon Scaphirhynchus albus (mean fork length FL = 538 ± 13 mm 90% confidence interval; mean weight = 518 ± 49 g) and ...indigenous shovelnose sturgeon S. platorynchus (mean FL = 525 ± 12 mm; mean weight = 683 ± 41 g) sampled in 2003 and 2004 from the Missouri River above Fort Peck Reservoir, Montana. Diet overlap between juvenile pallid sturgeon and shovelnose sturgeon was low. Fish were the primary prey of juvenile pallid sturgeon, and aquatic insects were the primary prey of shovelnose sturgeon. Sturgeon chub Macrhybopsis gelida and sicklefin chub M. meeki, two species that have declined throughout much of the Missouri River, comprised 79% of the number of identifiable fish in juvenile pallid sturgeon stomachs. The prevalence of sicklefin chub and sturgeon chub as a food resource of juvenile pallid sturgeon indicates that recovery and management of native cyprinids is a potentially important step in the recovery of pallid sturgeon.
Burbot, Lota lota (Linnaeus), is a regionally popular sportfish in the Wind River drainage of Wyoming, USA, at the southern boundary of the range of the species. Recent declines in burbot abundances ...were hypothesised to be caused by overexploitation, entrainment in irrigation canals and habitat loss. This study addressed the overexploitation hypothesis using tagging data to generate reliable exploitation, abundance and density estimates from a multistate capture–recapture model that accounted for incomplete angler reporting and tag loss. Exploitation rate μ was variable among the study lakes and inversely correlated with density. Exploitation thresholds μ40 associated with population densities remaining above 40% of carrying capacity were generated to characterise risk of overharvest using exploitation and density estimates from tagging data and a logistic surplus‐production model parameterised with data from other burbot populations. Bull Lake (μ = 0.06, 95% CI: 0.03–0.11; μ40 = 0.18) and Torrey Lake (μ = 0.02, 95% CI: 0.00–0.11; μ40 = 0.18) had a low risk of overfishing, Upper Dinwoody Lake had intermediate risk (μ = 0.08, 95% CI: 0.02–0.32; μ40 = 0.18) and Lower Dinwoody Lake had high risk (μ = 0.32, 95% CI: 0.10–0.67; μ40 = 0.08). These exploitation and density estimates can be used to guide sustainable management of the Wind River drainage recreational burbot fishery and inform management of other burbot fisheries elsewhere.
One of the most profound changes in the interest group sector over the last fifty years is interest groups’ increasing need to attract financial donors in order to assure long-term sustainability. ...Groups’ growing propensity to attract ‘chequebook’ members is thought to compromise their ability to foster the personal involvement of individuals in their communities. Yet we know very little about the consequences of these dynamics for the strength of the interest group sector in American communities. This widespread macro-level analysis of the interest group sector indicates that human capital is more important than financial capital for the strength of a community's interest group sector. Financially disadvantaged communities may still enjoy the benefits of a strong interest group sector provided they have a citizenry equipped with time to donate.
The General Antiparticle Spectrometer (GAPS) is an upcoming balloon mission to measure low-energy cosmic-ray antinuclei during at least three ~35-day Antarctic flights. With its large geometric ...acceptance and novel exotic atom-based particle identification, GAPS will detect ~500 cosmic antiprotons per flight and produce a precision cosmic antiproton spectrum in the kinetic energy range of ~0.07–0.21 GeV/n at the top of the atmosphere. With these high statistics extending to lower energies than any previous experiment, and with complementary sources of experimental uncertainty compared to traditional magnetic spectrometers, the GAPS antiproton measurement will be sensitive to dark matter, primordial black holes, and cosmic ray propagation. The antiproton measurement will also validate the GAPS antinucleus identification technique for the antideuteron and antihelium rare-event searches. Finally, this analysis demonstrates the GAPS sensitivity to cosmic-ray antiprotons using a full instrument simulation and event reconstruction, and including solar and atmospheric effects.
That Democrats are widely perceived as a pro‐choice party while Republicans are generally perceived as a pro‐life party seems apparent to even the most casual observer of American politics. Yet, this ...perception was not always as clear as it is today. Our understanding of the partisan evolution of the abortion issue in the United States is informed by previous research demonstrating that changes in the abortion issue at both the elite and mass level conform to Carmines and Stimson's issue evolution model of partisan dynamics. However, an important piece of this puzzle remains unresolved—how does the issue differentiation between the parties get communicated from elite party actors to the mass public? Analyzing over 30 years of several sources of news coverage on abortion, we show that over time, news stories revealed a closer link between particular interest groups and political parties, with the Republican Party becoming aligned with pro‐life interest groups while the Democrats were identified with pro‐choice groups. We posit that media coverage of the interaction between interest groups and political parties on abortion highlighted the issue's increasing political relevance in the minds of the American public and helped to communicate the parties' evolving issue positions to the wider electorate.
Que el partido demócrata está a favor del aborto mientras que el partido republicano está en contra parece obvio aún para cualquier observador de la política estadounidense. A pesar de esto, esta división no siempre fue tan clara como lo es ahora. Nuestra comprensión de la evolución del tópico del aborto en los partidos de los Estados Unidos está fundada en investigaciones previas que demuestran que los cambios en el tema del aborto, tanto en la elite como el público, se ajustan al modelo de evolución de las dinámicas partidistas de Carmines and Stimson. Sin embargo, una pieza importante de este rompecabezas queda sin resolver—¿cómo se comunican las diferencias entre las posturas partidistas sobre diversos asuntos, desde las elites partidistas al público en general? Analizando varias fuentes sobre la cobertura de noticias del aborto por cerca de 30 años, demostramos que a través del tiempo las noticias revelan un vínculo más cercano entre grupos de intereses particulares y los partidos políticos, con el partido republicano favoreciendo a los grupos de interés pro‐vida y los demócratas a los grupos pro‐aborto. Proponemos que la cobertura de los medios sobre la interacción entre los grupos de interés y los partidos políticos sobre el aborto puso de manifiesto la creciente relevancia del tópico en las mentes del público estadounidense y ayudó a comunicar al electorado cómo evolucionaron las posiciones de los partidos.
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![[sup.87]Sr/[sup.86]Sr isoto...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0706-652X/small "[sup.87]Sr/[sup.86]Sr isotope ratio analysis by laser ablation MC-ICP-MS in scales, spines, and fin rays as a nonlethal alternative to otoliths for reconstructing fish life history")
