Response of the upper atmosphere to variations in the solar soft x-ray irradiance

Terrestrial far ultraviolet (FUV) airglow emissions have been suggested as a means for remote sensing the structure of the upper atmosphere. The energy which leads to the excitation of FUV airglow emissions is solar irradiance at extreme ultraviolet (EUV) and soft x-ray wavelengths. Solar irradiance at these wavelengths is known to be highly variable; studies of nitric oxide (NO) in the lower thermosphere have suggested a variability of more than an order of magnitude in the solar soft x-ray irradiance. To properly interpret the FUV airflow, the magnitude of the solar energy deposition must be known. Previous analyses have used the electron impact excited Lyman-Birge-Hopfield (LBH) bands of N2 to infer the flux of photoelectrons in the atmosphere and thus to infer the magnitude of the solar irradiance. This dissertation presents the first simultaneous measurements of the FUV airglow, the major atmospheric constituent densities, and the solar EUV and soft x-ray irradiances. The measurements were made on three flights of an identical sounding rocket payload at different levels of solar activity. The linear response in brightness of the LBH bands to variations in solar irradiance is demonstrated. In addition to the N2 LBH bands, atomic oxygen lines at 135.6 and 130.4 nm are also studied. Unlike the LBH bands, these emissions undergo radiative transfer effects in the atmosphere. The OI emission at 135.6 nm is found to be well modeled using a radiative transfer calculation and the known excitation processes. Unfortunately, the assumed processes leading to OI 130.4 nm excitation are found to be insufficient to reproduce the observed variability of this emission. Production of NO in the atmosphere is examined; it is shown that a lower than previously reported variability in the solar soft x-ray irradiance is required to explain the variability of NO

A cross-sectional survey of the perspectives of older people in the Scottish Highlands on the management of their chronic pain.

Background: Although there is evidence of suboptimal outcomes in older people with chronic pain, little emphasis has been placed on those in remote and rural settings. Objective: To describe the perspectives of older people in the Scottish Highlands on their chronic pain management. Design: Cross-sectional survey. Setting: NHS Highland, the most remote and rural geographical health board in Scotland. Subjects: Home-dwelling members of the public aged ≥70 years. Methods: Anonymised questionnaires were mailed to a random sample of 1800 older people. Questionnaire items were demographics, nature of any chronic pain, management regimens and perceived effectiveness. Validated scales were the Pain Disability Questionnaire and the Tampa Scale for Kinesiophobia. Results: Adjusted response rate was 39.3% (709/1755). One-quarter (25.0%, n = 177) were experiencing chronic pain, being more likely to live in deprived areas (P < 0.05). Median pain intensity was 6 (IQR 4–7, 10 high), causing distress (median 5, IQR 3–7). Respondents largely consulted GPs (66.1%, n = 117) with a minority (16.4%, n = 29) referred to a specialist pain clinic and few consulting other health professionals. Over three quarters (78.0%, n = 138) were receiving prescribed medicines, most commonly paracetamol, alone (35.6%, n = 63) or in combination with opioids (16.4%, n = 29). One-third (31.6%, n = 56) expressed a desire for more effective medicines; few reported using any non-pharmacological therapies. The median scores for the Pain Disability Questionnaire and Tampa Scale for Kinesiophobia were 74 (IQR 34–104.5, 150 high) and 40 (IQR 35–45, 68 high). Conclusions: Evidence of provision of appropriate integrated and person-centred chronic pain care is lacking

A qualitative exploration of chronic pain management of older adults in remote and rural settings.

The World Health Organization predicts that the number of older adults will nearly double between 2015 and 2050. Older adults are at a higher risk of developing medical conditions such as chronic pain. However, there is little information about chronic pain and its management in older adults especially those residing in remote and rural areas. To explore views, experiences, and behavioural determinants of older adults regarding chronic pain management in remote and rural settings in Scottish Highlands. Qualitative one-to-one telephone interviews were conducted with older adults with chronic pain residing in remote and rural areas in the Scottish Highlands. The interview schedule was developed by the researchers, validated, and piloted prior to use. All interviews were audio-recorded, transcribed, and independently thematically-analysed by two researchers. Interviews continued until data saturation. Fourteen interviews were conducted with three key themes emerging: views and experiences with chronic pain, need to enhance pain management, and perceived barriers to pain management. Overall, pain was reported as severe and negatively impacted lives. Majority of interviewees used medicines for pain relief but noted that their pain was still poorly controlled. Interviewees had limited expectation for improvement since they considered their condition a normal consequence of ageing. Residing in remote and rural areas was perceived to complicate access to services with many having to travel long distances to see a health professional. Chronic pain management in remote and rural areas remains a significant issue among older adults interviewed. Thus, there is a need to develop approaches to improve access to related information and services. [Abstract copyright: © 2023. The Author(s).

Characterization of Ablation Product Radiation Signatures of PICA and FiberForm

Emission spectroscopy measurements in the post-shock layer in front of low density ablative material samples of different shapes were obtained in the NASA Langley HYMETS arcjet facility. A horizontal line of measurement positions was imaged on the entrance slit of the spectrometer allowing detection of the entire stagnation line in front of the samples. The stagnation line measurements were used to compare the post-shock layer emission signatures in front of PICA and FiberForm. The emission signatures of H, NH, and OH are characteristic for pyrolysis gases and consequently were only observed in front of the PICA samples. CN and C were found in front of both materials and are mainly due to interactions of the carbon fibers with the plasma. In all tests with instrumented samples, the emission of Mn, Cr, and Ni was observed when the thermocouple temperatures reached or exceeded ~1,500 K, strongly indicating erosion of the molten thermocouple tips. Temperatures in the post-shock layer were estimated from comparing the CN band emission to spectral simulation. The resulting rotational and vibrational temperatures were on the order of 7,000 to 9,000 K and close to each other indicating a plasma condition close to equilibrium. In addition to the stagnation line configurations, off-axis lines of observation were investigated to gather information about spalled particles in the flow. From a comparison of measured continuum emission with simulated Planck radiation, average particle temperatures along the measured line of observation were determined for two cases. Particle temperatures between 3,500 and 2,000 K were found. A comprehensive investigation of the entire amount of data set is ongoing

Prediction of the in situ coronal mass ejection rate for solar cycle 25: Implications for Parker Solar Probe in situ observations

The Parker Solar Probe (PSP) and Solar Orbiter missions are designed to make groundbreaking observations of the Sun and interplanetary space within this decade. We show that a particularly interesting in situ observation of an interplanetary coronal mass ejection (ICME) by PSP may arise during close solar flybys ($< 0.1$~AU). During these times, the same magnetic flux rope inside an ICME could be observed in situ by PSP twice, by impacting its frontal part as well as its leg. Investigating the odds of this situation, we forecast the ICME rate in solar cycle 25 based on 2 models for the sunspot number (SSN): (1) the forecast of an expert panel in 2019 (maximum SSN = 115), and (2) a prediction by McIntosh et al. (2020, maximum SSN = 232). We link the SSN to the observed ICME rates in solar cycles 23 and 24 with the Richardson and Cane list and our own ICME catalog, and calculate that between 1 and 7 ICMEs will be observed by PSP at heliocentric distances $< 0.1$ AU until 2025, including 1$\sigma$ uncertainties. We then model the potential flux rope signatures of such a double-crossing event with the semi-empirical 3DCORE flux rope model, showing a telltale elevation of the radial magnetic field component $B_R$, and a sign reversal in the component $B_N$ normal to the solar equator compared to field rotation in the first encounter. This holds considerable promise to determine the structure of CMEs close to their origin in the solar corona.Comment: 11 pages, 6 figures, accepted for publication in the Astrophysical Journal on 2020 September 1

Selenium deficiency is widespread and spatially dependent in Ethiopia

Selenium (Se) is an essential element for human health and livestock productivity. Globally, human Se status is highly variable, mainly due to the influence of soil types on the Se content of crops, suggesting the need to identify areas of deficiency to design targeted interventions. In sub-Saharan Africa, including Ethiopia, data on population Se status are largely unavailable, although previous studies indicated the potential for widespread Se deficiency. Serum Se concentration of a nationally representative sample of the Ethiopian population was determined, and these observed values were combined with a spatial statistical model to predict and map the Se status of populations across the country. The study used archived serum samples (n = 3269) from the 2015 Ethiopian National Micronutrient Survey (ENMS). The ENMS was a cross-sectional survey of young and school-age children, women and men. Serum Se concentration was measured using inductively coupled plasma mass spectrometry (ICPMS). The national median (Q1, Q3) serum Se concentration was 87.7 (56.7, 123.0) μg L−1. Serum Se concentration differed between regions, ranging from a median (Q1, Q3) of 54.6 (43.1, 66.3) µg L−1 in the Benishangul-Gumuz Region to 122.0 (105, 141) µg L−1 in the Southern Nations, Nationalities, and Peoples’ Region and the Afar Region. Overall, 35.5% of the population were Se deficient, defined as serum Se < 70 µg L−1. A geostatistical analysis showed that there was marked spatial dependence in Se status, with serum concentrations greatest among those living in North-East and Eastern Ethiopia and along the Rift Valley, while serum Se concentrations were lower among those living in North-West and Western Ethiopia. Selenium deficiency in Ethiopia is widespread, but the risk of Se deficiency is highly spatially dependent. Policies to enhance Se nutrition should target populations in North-West and Western Ethiopi

Site-specific factors influence the field performance of a Zn-biofortified wheat variety

Background: Biofortification of wheat with zinc (Zn) through breeding and agronomy can reduce Zn deficiencies and improve human health. ‘High-Zn’ wheat varieties have been released in India and Pakistan, where wheat is consumed widely as a dietary staple. The aim of this study was to quantify the potential contribution of a ‘high-Zn’ wheat variety (Triticum aestivum L. var. Zincol-2016) and Zn fertilisers to improving dietary Zn supply under field conditions in Pakistan. Methods: Grain Zn concentration of Zincol-2016 and local reference varieties were determined at three sites of contrasting soil Zn status: Faisalabad (Punjab Province; diethylenetriamine pentaacetate- (DTPA-)extractable Zn, 1.31 mg kg-1 soil; gross plot size 13.3 m2; n=4; reference var. Faisalabad-2008), Islamabad (Capital Territory; 0.48 mg kg-1; 4.6 m2; n=5; reference var. NARC-2011), and Pir Sabak (Khyber Pakhtunkhwa, KPK, Province; 0.12 mg kg-1 soil; 9.1 m2; n=4; reference vars. Pirsabak-2015, Wadhan-2017). Eight Zn fertiliser treatment levels were tested using a randomised complete block design: control; soil (5 or 10 kg ha-1 ZnSO4.H2O; 33% Zn applied at sowing); foliar (0.79 or 1.58 kg of ZnSO4.H2O ha-1 applied as a 250 L ha-1 drench at crop booting stage); three soil foliar combinations. Results: At the Faisalabad site, the grain Zn concentration of Zincol-2016 was greater than Faisalabad-2008, with no yield penalty. Zincol-2016 did not have larger grain Zn concentrations than reference varieties used at Islamabad or Pir Sabak sites, which both had a lower soil Zn status than the Faisalabad site. Foliar Zn fertilisation increased grain Zn concentration of all varieties at all sites. There were no significant effects of soil Zn fertilisers, or variety·fertiliser interactions, on grain Zn concentration or yield. Conclusions: Environment and management affect the performance of ‘high-Zn’ wheat varieties, and these factors needs to be evaluated at scale to assess the potential nutritional impact of Zn biofortified crops. Designing studies to detect realistic effect sizes for new varieties and crop management strategies is therefore an important consideration. The current study indicated that nine replicate plots would be needed to achieve 80% power to detect a 25% increase in grain Zn concentration

The refreezing of melt ponds on Arctic sea ice

The presence of melt ponds on the surface of Arctic sea ice significantly reduces its albedo, inducing a positive feedback leading to sea ice thinning. While the role of melt ponds in enhancing the summer melt of sea ice is well known, their impact on suppressing winter freezing of sea ice has, hitherto, received less attention. Melt ponds freeze by forming an ice lid at the upper surface, which insulates them from the atmosphere and traps pond water between the underlying sea ice and the ice lid. The pond water is a store of latent heat, which is released during refreezing. Until a pond freezes completely, there can be minimal ice growth at the base of the underlying sea ice. In this work, we present a model of the refreezing of a melt pond that includes the heat and salt balances in the ice lid, trapped pond, and underlying sea ice. The model uses a two-stream radiation model to account for radiative scattering at phase boundaries. Simulations and related sensitivity studies suggest that trapped pond water may survive for over a month. We focus on the role that pond salinity has on delaying the refreezing process and retarding basal sea ice growth. We estimate that for a typical sea ice pond coverage in autumn, excluding the impact of trapped ponds in models overestimates ice growth by up to 265 million km3, an overestimate of 26%

Dietary iron intakes based on food composition data may underestimate the contribution of potentially exchangeable contaminant iron from soil

Iron intakes calculated from one-day weighed records were compared with those from same day analyzed duplicate diet composites collected from 120 Malawian women living in two rural districts with contrasting soil mineralogy and where threshing may contaminate cereals with soil iron. Soils and diet composites from the two districts were then subjected to a simulated gastrointestinal digestion and iron availability in the digests measured using a Caco-2 cell model. Median analyzed iron intakes (mg/d) were higher (p < 0.001) than calculated intakes in both Zombwe (16.6 vs. 10.1 mg/d) and Mikalango (29.6 vs. 19.1 mg/d), attributed to some soil contaminant iron based on high Al and Ti concentrations in diet composites. A small portion of iron in acidic soil from Zombwe, but not Mikalango calcareous soil, was bioavailable, as it induced ferritin expression in the cells, and may have contributed to higher plasma ferritin and total body iron for the Zombwe women reported earlier, despite lower iron intakes. In conclusion, iron intakes calculated from food composition data were underestimated, highlighting the importance of analyzing duplicate diet composites where extraneous contaminant iron from soil is likely. Acidic contaminant soil may make a small but useful contribution to iron nutrition