| 1. |
|
|
| 2. |
-
- 2017
-
Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:2
-
Tidskriftsartikel (refereegranskat)
|
|
| 3. |
-
- 2019
-
Tidskriftsartikel (refereegranskat)
|
|
| 4. |
|
|
| 5. |
- Quanz, S. P., et al.
(författare)
-
Large Interferometer For Exoplanets (LIFE) I. Improved exoplanet detection yield estimates for a large mid-infrared space-interferometer mission
- 2022
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 664
-
Tidskriftsartikel (refereegranskat)abstract
- Context. One of the long-term goals of exoplanet science is the atmospheric characterization of dozens of small exoplanets in order to understand their diversity and search for habitable worlds and potential biosignatures. Achieving this goal requires a space mission of sufficient scale that can spatially separate the signals from exoplanets and their host stars and thus directly scrutinize the exoplanets and their atmospheres.Aims. We seek to quantify the exoplanet detection performance of a space-based mid-infrared (MIR) nulling interferometer that measures the thermal emission of exoplanets. We study the impact of various parameters and compare the performance with that of large single-aperture mission concepts that detect exoplanets in reflected light.Methods. We have developed an instrument simulator that considers all major astrophysical noise sources and coupled it with Monte Carlo simulations of a synthetic exoplanet population around main-sequence stars within 20 pc of the Sun. This allows us to quantify the number (and types) of exoplanets that our mission concept could detect. Considering single visits only, we discuss two different scenarios for distributing 2.5 yr of an initial search phase among the stellar targets. Different apertures sizes and wavelength ranges are investigated.Results. An interferometer consisting of four 2 m apertures working in the 4–18.5 μ.m wavelength range with a total instrument throughput of 5% could detect up to ≈550 exoplanets with radii between 0.5 and 6 R⊕ with an integrated S/N ≥ 7. At least ≈160 of the detected exoplanets have radii ≤1.5 R⊕. Depending on the observing scenario, ≈25–45 rocky exoplanets (objects with radii between 0.5 and 1.5 R⊕) orbiting within the empirical habitable zone (eHZ) of their host stars are among the detections. With four 3.5 m apertures, the total number of detections can increase to up to ≈770, including ≈60–80 rocky eHZ planets. With four times 1 m apertures, the maximum detection yield is ≈315 exoplanets, including ≤20 rocky eHZ planets. The vast majority of small, temperate exoplanets are detected around M dwarfs. The impact of changing the wavelength range to 3–20 μm or 6–17 μm on the detection yield is negligible.Conclusions. A large space-based MIR nulling interferometer will be able to directly detect hundreds of small, nearby exoplanets, tens of which would be habitable world candidates. This shows that such a mission can compete with large single-aperture reflected light missions. Further increasing the number of habitable world candidates, in particular around solar-type stars, appears possible via the implementation of a multi-visit strategy during the search phase. The high median S/N of most of the detected planets will allow for first estimates of their radii and effective temperatures and will help prioritize the targets for a second mission phase to obtain high-S/N thermal emission spectra, leveraging the superior diagnostic power of the MIR regime compared to shorter wavelengths.
|
|
| 6. |
- Alimena, Juliette, et al.
(författare)
-
Searching for long-lived particles beyond the Standard Model at the Large Hadron Collider
- 2020
-
Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 47:9
-
Tidskriftsartikel (refereegranskat)abstract
- Particles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at the weak scale. When produced at experiments such as the Large Hadron Collider (LHC) at CERN, these long-lived particles (LLPs) can decay far from the interaction vertex of the primary proton-proton collision. Such LLP signatures are distinct from those of promptly decaying particles that are targeted by the majority of searches for new physics at the LHC, often requiring customized techniques to identify, for example, significantly displaced decay vertices, tracks with atypical properties, and short track segments. Given their non-standard nature, a comprehensive overview of LLP signatures at the LHC is beneficial to ensure that possible avenues of the discovery of new physics are not overlooked. Here we report on the joint work of a community of theorists and experimentalists with the ATLAS, CMS, and LHCb experiments-as well as those working on dedicated experiments such as MoEDAL, milliQan, MATHUSLA, CODEX-b, and FASER-to survey the current state of LLP searches at the LHC, and to chart a path for the development of LLP searches into the future, both in the upcoming Run 3 and at the high-luminosity LHC. The work is organized around the current and future potential capabilities of LHC experiments to generally discover new LLPs, and takes a signature-based approach to surveying classes of models that give rise to LLPs rather than emphasizing any particular theory motivation. We develop a set of simplified models; assess the coverage of current searches; document known, often unexpected backgrounds; explore the capabilities of proposed detector upgrades; provide recommendations for the presentation of search results; and look towards the newest frontiers, namely high-multiplicity 'dark showers', highlighting opportunities for expanding the LHC reach for these signals.
|
|
| 7. |
- Mishra, U., et al.
(författare)
-
Empirical estimates to reduce modeling uncertainties of soil organic carbon in permafrost regions : a review of recent progress and remaining challenges
- 2013
-
Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 8:3, s. 035020-
-
Tidskriftsartikel (refereegranskat)abstract
- The vast amount of organic carbon (OC) stored in soils of the northern circumpolar permafrost region is a potentially vulnerable component of the global carbon cycle. However, estimates of the quantity, decomposability, and combustibility of OC contained in permafrost-region soils remain highly uncertain, thereby limiting our ability to predict the release of greenhouse gases due to permafrost thawing. Substantial differences exist between empirical and modeling estimates of the quantity and distribution of permafrost-region soil OC, which contribute to large uncertainties in predictions of carbon-climate feedbacks under future warming. Here, we identify research challenges that constrain current assessments of the distribution and potential decomposability of soil OC stocks in the northern permafrost region and suggest priorities for future empirical and modeling studies to address these challenges.
|
|
| 8. |
- Cilliers, S. S., et al.
(författare)
-
Garden ecosystem services of Sub-Saharan Africa and the role of health clinic gardens as social-ecological systems
- 2018
-
Ingår i: Landscape and Urban Planning. - : Elsevier BV. - 0169-2046 .- 1872-6062. ; 180, s. 294-307
-
Tidskriftsartikel (refereegranskat)abstract
- Rapid urbanization is predicted to take place in Africa in the near future and currently stressed cities will be even more overburdened in terms of pressure on green areas and increasing urban poverty. Effectively planning for and conserving current urban green infrastructure will be essential to ensure resilience and maintenance of quality urban environments. Gardens represent major portions of urban green infrastructure. In this paper we review literature to determine the current status of garden ecosystem services under the main themes of provisioning, regulating, supporting and cultural services in sub-Saharan Africa and identify the current challenges in optimizing these ecosystem services. Studying gardens as social-ecological systems might be the key to promote and enhance their resilience capacity in a changing world, acknowledging the fact that gardens are communities of practice in which social learning may occur. Studies on health clinic gardens in the North-West Province of South Africa have indicated how some of the challenges in terms of optimizing garden ecosystem services can be addressed. Multiple stakeholders involved in the health clinic gardens contribute towards a co-production of knowledge that could lead to social learning on aspects such as cultivation of nutritious food. More detailed studies on health clinic gardens are however, necessary to be able to develop a community-based resource management framework that can be implemented in the North-West Province and potentially in other South African provinces and countries in Sub-Saharan Africa.
|
|
| 9. |
- Gao, M., et al.
(författare)
-
Associations of birth characteristics with perimenopausal disorders : a prospective cohort study
- 2019
-
Ingår i: Journal of Developmental Origins of Health and Disease. - 2040-1744 .- 2040-1752. ; 10:2, s. 246-252
-
Tidskriftsartikel (refereegranskat)abstract
- Perimenopausal disorders (PDs) are prevalent and importantly affect quality of life among middle-aged women. Yet, very little is known about the developmental origins of these disorders. The objective of this study was to investigate the associations of birth characteristics with PDs. This cohort study is based on archived birth records for birth weight and gestational age, and followed prospectively in Swedish inpatient and outpatient registers for 8 years (n=3212). The main outcomes were menopausal and climacteric states (e.g. flushing, sleeplessness), perimenopausal bleeding and other PDs (e.g. atrophic vaginitis). Cox proportional hazards regression models were used to estimate the hazard ratios (HRs) for three subtypes of PDs separately. During the follow-up, 218 women had PDs, among whom 125 had menopausal and climacteric states, 61 had perimenopausal bleeding and 58 had other PDs as first recorded disorder. Birth weight was linearly associated with incidence rate of menopausal and climacteric states [HR=1.66 per 1 kg increase, 95% confidence interval (95% CI)=1.14-2.41]. Gestational age (rather than birth weight) was associated with incidence rate of other PDs (HR=0.87 per 1 week increase, 95% CI=0.79-0.95). Neither birth weight nor gestational age was associated with perimenopausal bleeding. Similar results were found after adjustment for other early-life and adult socio-demographic characteristics. This observational study provides, for the first time, evidence regarding the developmental origins of PDs. Future research is required to investigate the underlying causal mechanisms, which may shed further light on the etiology of this class of disorders.
|
|
| 10. |
|
|
