| 1. |
- Leisawitz, David, et al.
(author)
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The origins space telescope
- 2019
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 11115
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Conference paper (peer-reviewed)abstract
- The Origins Space Telescope will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did galaxies evolve from the earliest galactic systems to those found in the universe today? How do habitable planets form? How common are life-bearing worlds? To answer these alluring questions, Origins will operate at mid-and far-infrared wavelengths and offer powerful spectroscopic instruments and sensitivity three orders of magnitude better than that of Herschel, the largest telescope flown in space to date. After a 3 1/2 year study, the Origins Science and Technology Definition Team will recommend to the Decadal Survey a concept for Origins with a 5.9-m diameter telescope cryocooled to 4.5 K and equipped with three scientific instruments. A mid-infrared instrument (MISC-T) will measure the spectra of transiting exoplanets in the 2.8-20 μm wavelength range and offer unprecedented sensitivity, enabling definitive biosignature detections. The Far-IR Imager Polarimeter (FIP) will be able to survey thousands of square degrees with broadband imaging at 50 and 250 μm. The Origins Survey Spectrometer (OSS) will cover wavelengths from 25-588 μm, make wide-area and deep spectroscopic surveys with spectral resolving power R ∼ 300, and pointed observations at R ∼ 40,000 and 300,000 with selectable instrument modes. Origins was designed to minimize complexity. The telescope has a Spitzer-like architecture and requires very few deployments after launch. The cryo-thermal system design leverages JWST technology and experience. A combination of current-state-of-the-art cryocoolers and next-generation detector technology will enable Origins' natural backgroundlimited sensitivity.
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| 2. |
- Leisawitz, David, et al.
(author)
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Origins Space Telescope: Baseline mission concept
- 2021
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In: Journal of Astronomical Telescopes, Instruments, and Systems. - 2329-4221 .- 2329-4124. ; 7:1
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Journal article (peer-reviewed)abstract
- The Origins Space Telescope will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did galaxies evolve from the earliest galactic systems to those found in the Universe today? How do habitable planets form? How common are life-bearing worlds? To answer these alluring questions, Origins will operate at mid-and far-infrared (IR) wavelengths and offer powerful spectroscopic instruments and sensitivity three orders of magnitude better than that of the Herschel Space Observatory, the largest telescope flown in space to date. We describe the baseline concept for Origins recommended to the 2020 US Decadal Survey in Astronomy and Astrophysics. The baseline design includes a 5.9-m diameter telescope cryocooled to 4.5 K and equipped with three scientific instruments. A mid-infrared instrument (Mid-Infrared Spectrometer and Camera Transit spectrometer) will measure the spectra of transiting exoplanets in the 2.8 to 20 μm wavelength range and offer unprecedented spectrophotometric precision, enabling definitive exoplanet biosignature detections. The far-IR imager polarimeter will be able to survey thousands of square degrees with broadband imaging at 50 and 250 μm. The Origins Survey Spectrometer will cover wavelengths from 25 to 588 μm, making wide-area and deep spectroscopic surveys with spectral resolving power R ∼ 300, and pointed observations at R ∼ 40,000 and 300,000 with selectable instrument modes. Origins was designed to minimize complexity. The architecture is similar to that of the Spitzer Space Telescope and requires very few deployments after launch, while the cryothermal system design leverages James Webb Space Telescope technology and experience. A combination of current-state-of-the-art cryocoolers and next-generation detector technology will enable Origins' natural background-limited sensitivity.
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| 4. |
- Aston, Eoghan A., et al.
(author)
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Scale-dependent spatial patterns in benthic communities around a tropical island seascape
- 2019
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In: Ecography. - : Wiley. - 0906-7590 .- 1600-0587. ; 42:3, s. 578-590
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Journal article (peer-reviewed)abstract
- Understanding and predicting patterns of spatial organization across ecological communities is central to the field of landscape ecology, and a similar line of inquiry has begun to evolve sub-tidally among seascape ecologists. Much of our current understanding of the processes driving marine community patterns, particularly in the tropics, has come from small-scale, spatially-discrete data that are often not representative of the broader seascape. Here we expand the spatial extent of seascape ecology studies and combine spatially-expansive in situ digital imagery, oceanographic measurements, spatial statistics, and predictive modeling to test whether predictable patterns emerge between coral reef benthic competitors across scales in response to intra-island gradients in physical drivers. We do this around the entire circumference of a remote, uninhabited island in the central Pacific (Jarvis Island) that lacks the confounding effects of direct human impacts. We show, for the first time, that competing benthic groups demonstrate predictable scaling patterns of organization, with positive autocorrelation in the cover of each group at scales < similar to 1 km. Moreover, we show how gradients in subsurface temperature and surface wave power drive spatially-abrupt transition points in group dominance, explaining 48-84% of the overall variation in benthic cover around the island. Along the western coast, we documented ten times more sub-surface cooling-hours than any other part of the coastline, with events typically resulting in a drop of 1-4 degrees C over a period of < 5 h. These high frequency temperature fluctuations are indicative of upwelling induced by internal waves and here result in localized nitrogen enrichment (NO2 + NO3) that promotes hard coral dominance around 44% of the island's perimeter. Our findings show that, in the absence of confounding direct human impacts, the spatial organization of coral reef benthic competitors are predictable and somewhat bounded across the seascape by concurrent gradients in physical drivers.
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| 5. |
- Butler, T., et al.
(author)
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Glymphatic clearance estimated using diffusion tensor imaging along perivascular spaces is reduced after traumatic brain injury and correlates with plasma neurofilament light, a biomarker of injury severity
- 2023
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In: Brain Communications. - 2632-1297. ; 5:3
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Journal article (peer-reviewed)abstract
- Using an MRI technique called diffusion tensor imaging along perivascular space to estimate brain glymphatic clearance, Butler et al. demonstrate clearance reductions in subjects with traumatic brain injury as compared with healthy controls and in association with a blood biomarker of injury severity. The glymphatic system is a perivascular fluid clearance system, most active during sleep, considered important for clearing the brain of waste products and toxins. Glymphatic failure is hypothesized to underlie brain protein deposition in neurodegenerative disorders like Alzheimer's disease. Preclinical evidence suggests that a functioning glymphatic system is also essential for recovery from traumatic brain injury, which involves release of debris and toxic proteins that need to be cleared from the brain. In a cross-sectional observational study, we estimated glymphatic clearance using diffusion tensor imaging along perivascular spaces, an MRI-derived measure of water diffusivity surrounding veins in the periventricular region, in 13 non-injured controls and 37 subjects who had experienced traumatic brain injury similar to 5 months previously. We additionally measured the volume of the perivascular space using T-2-weighted MRI. We measured plasma concentrations of neurofilament light chain, a biomarker of injury severity, in a subset of subjects. Diffusion tensor imaging along perivascular spaces index was modestly though significantly lower in subjects with traumatic brain injury compared with controls when covarying for age. Diffusion tensor imaging along perivascular spaces index was significantly, negatively correlated with blood levels of neurofilament light chain. Perivascular space volume did not differ in subjects with traumatic brain injury as compared with controls and did not correlate with blood levels of neurofilament light chain, suggesting it may be a less sensitive measure for injury-related perivascular clearance changes. Glymphatic impairment after traumatic brain injury could be due to mechanisms such as mislocalization of glymphatic water channels, inflammation, proteinopathy and/or sleep disruption. Diffusion tensor imaging along perivascular spaces is a promising method for estimating glymphatic clearance, though additional work is needed to confirm results and assess associations with outcome. Understanding changes in glymphatic functioning following traumatic brain injury could inform novel therapies to improve short-term recovery and reduce later risk of neurodegeneration.
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| 6. |
- Irani, I., et al.
(author)
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Less Than 1% of Core-collapse Supernovae in the Local Universe Occur in Elliptical Galaxies
- 2022
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In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 927:1
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Journal article (peer-reviewed)abstract
- We present observations of three core-collapse supernovae (CCSNe) in elliptical hosts, detected by the Zwicky Transient Facility Bright Transient Survey (BTS). SN 2019ape is a SN Ic that exploded in the main body of a typical elliptical galaxy. Its properties are consistent with an explosion of a regular SN Ic progenitor. A secondary g-band light-curve peak could indicate interaction of the ejecta with circumstellar material (CSM). An Ha-emitting source at the explosion site suggests a residual local star formation origin. SN 2018fsh and SN 2020uik are SNe II which exploded in the outskirts of elliptical galaxies. SN 2020uik shows typical spectra for SNe II, while SN 2018fsh shows a boxy nebular Ha profile, a signature of CSM interaction. We combine these 3 SNe with 7 events from the literature and analyze their hosts as a sample. We present multi-wavelength photometry of the hosts, and compare this to archival photometry of all BTS hosts. Using the spectroscopically complete BTS, we conclude that 0.3%(+0.3)(-0.1) of all CCSNe occur in elliptical galaxies. We derive star formation rates and stellar masses for the host galaxies and compare them to the properties of other SN hosts. We show that CCSNe in ellipticals have larger physical separations from their hosts compared to SNe Ia in elliptical galaxies, and discuss implications for star-forming activity in elliptical galaxies.
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| 7. |
- Verguet, Stéphane, et al.
(author)
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Impact of supplemental immunisation activity (SIA) campaigns on health systems : findings from South Africa
- 2013
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In: Journal of Epidemiology and Community Health. - : BMJ Publishing Group. - 0143-005X .- 1470-2738. ; 67:11, s. 947-952
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Journal article (peer-reviewed)abstract
- Background Supplemental immunisation activity (SIA) campaigns provide children with an additional dose of measles vaccine and deliver other childhealth interventions including vitamin A supplements, deworming medications and oral polio vaccines. They also require the mobilisation of a large health workforce. We assess the impact of the implementation of SIA campaigns on selected routine child and maternalhealth services in South Africa (SA).Methods We use district-level monthly headcount data for 52 South African districts for the period 2001-2010, sourced from the District Health Information System, SA. The data include 12 child and maternalhealth headcount indicators including routine immunisation, and maternal and reproductivehealth indicators. We analyse the association between the implementation of the 2010 SIA campaign and the change (decrease/increase) in headcounts, using a linear regression model.Results We find a significant decrease for eight indicators. The total number of fully immunised children before age 1 decreased by 29% (95% CI 23% to 35%, p<0.001) during the month of SIA implementation; contraceptive use and antenatal visits decreased by 7-17% (p0.02) and about 10% (p<0.001), respectively.Conclusions SIA campaigns may negatively impact health systems during the period of implementation by disrupting regular functioning and diverting resources from other activities, including routine child and maternal health services. SIA campaigns present multidimensional costs that need to be explicitly considered in benefit-cost assessments.
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| 8. |
- Verguet, Stephane, et al.
(author)
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Measles control in Sub-Saharan Africa : South Africa as a case study
- 2012
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In: Vaccine. - Oxford : Elsevier. - 0264-410X .- 1873-2518. ; 30:9, s. 1594-1600
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Journal article (peer-reviewed)abstract
- Background: Due to intensified measles immunization efforts, measles mortality has decreased substantially worldwide, particularly in Sub-Saharan Africa (SSA). The World Health Organization (WHO) estimated a 92% decrease in measles-related deaths in the WHO AFRO region for the period 2000-2008. Recently, the AFRO region established a measles pre-elimination goal and experts have suggested engaging in a measles eradication campaign at the global level. However, recent large-scale outbreaks in many Sub-Saharan African countries present a challenge to measles control efforts. This paper examines measles immunization and the impact of measles supplemental immunization activities (SlAs) on routine immunization coverage in South Africa (SA). Methods: We reported on immunization coverage trends in SA for the period 2001-2010 at the province and district levels. The data included routine immunization for 1st and 2nd doses of measles vaccine (MCV1, MCV2), SlAs, 1st dose of Bacille Calmette-Guerin vaccine, 1st and 3rd doses of oral polio vaccine (OPV1, OPV3), 3rd dose of Diphtheria-Tetanus-Pertussis-Haemophilus-influenzae-B vaccine (DTP-Hib3), and the number of under-one-year-olds having completed a primary course of immunization (Imm1). A regression model looked at the SIA impact on routine coverage. Results: Over the past decade, MCV1 and MCV2 coverage have increased nationally from 68% and 57% in 2001 to 95% and 83% in 2010, respectively. SIA coverage has remained at high levels, around 90%, over the same period. Substantial heterogeneity in MCV1 and MCV2 coverage is present across SA districts, with differences in coverage of 56% (MCV1) and 51% (MCV2) in 2010. In any given year, occurrence of SlAs was associated with a decrease in routine immunization coverage of MCV1, MCV2, OPV1, OPV3, DTP-Hib3, and Imm1, at the district level. Conclusions: The heterogeneity in measles vaccination coverage across SA districts challenges the goal of measles elimination in SA and SSA. The reduction in routine immunization coverage associated with the occurrence of SlAs raises the legitimate concern that SlAs may negatively impact health systems' functioning. (C) 2012 Elsevier Ltd. All rights reserved.
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| 9. |
- Verguet, Stephane, et al.
(author)
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Supplementary immunization activities (SIAs) in South Africa : comprehensive economic evaluation of an integrated child health delivery platform
- 2013
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In: Global Health Action. - : Informa UK Limited. - 1654-9716 .- 1654-9880. ; 6, s. 1-9
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Journal article (peer-reviewed)abstract
- Background: Supplementary immunization activity (SIA) campaigns provide children with an additional dose of measles vaccine and deliver other interventions, including vitamin A supplements, deworming medications, and oral polio vaccines.Objective: To assess the cost-effectiveness of the full SIA delivery platform in South Africa (SA).Design: We used an epidemiologic cost model to estimate the cost-effectiveness of the 2010 SIA campaign. We used province-level campaign data sourced from the District Health Information System, SA, and from planning records of provincial coordinators of the Expanded Programme on Immunization. The data included the number of children immunized with measles and polio vaccines, the number of children given vitamin A supplements and Albendazole tablets, and costs.Results: The campaign cost $37 million and averted a total of 1,150 deaths (95% uncertainty range: 990-1,360)- This ranged from 380 deaths averted in KwaZulu-Natal to 20 deaths averted in the Northern Cape. Vitamin A supplementation alone averted 820 deaths (95% UR: 670-1,040); measles vaccination alone averted 330 deaths (95% UR: 280-370)- Incremental cost-effectiveness was $27,100 (95% UR: $18, 500-34,400) per death averted nationally, ranging from $11,300 per death averted in the Free State to $91,300 per death averted in the Eastern Cape.Conclusions: Cost-effectiveness of the SIA child health delivery platform varies substantially across SA provinces, and it is substantially more cost-effective when vitamin A supplementation is included in the interventions administered. Cost-effectiveness assessments should consider health system delivery platforms that integrate multiple interventions, and they should be conducted at the sub-national level.
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