Palliative care, homelessness, and restricted or uncertain immigration status.

Background: People experiencing homelessness have limited access to palliative care support despite high levels of ill health and premature mortality. Most research exploring these challenges in the United Kingdom has focused on people living in hostels or temporary accommodation. People with uncertain or restricted immigration status are often unable to access this accommodation due to lack of entitlement to benefits. There is little research about the experiences of those in the United Kingdom who cannot access hostels or temporary accommodation due to restricted or uncertain immigration status with regards to palliative and end-of-life care access. Aim: To explore the barriers to palliative and end-of-life care access for people with uncertain or restricted immigration status, who are experiencing homelessness and have advanced ill health, and the experiences of UK hospices of supporting people in this situation. Design: A multi-method cross-sectional study. Setting/participants: An online survey for hospice staff followed by online focus groups with staff from inclusion health, homelessness and palliative care services, charities and interviews with people experiencing homelessness. Results: Fifty hospice staff responded to the online survey and 17 people participated in focus groups and interviews (focus groups: n = 10; interviews: n = 7). The survey demonstrated how hospices are not currently supporting many people with restricted or uncertain immigration status who are homeless and that hospice staff have received limited training around eligibility for entitlements or National Health Service (NHS) care. Interview and focus group data demonstrated high levels of unmet need. Reasons for this included a lack of consistency around eligibility for support from local authorities, issues relating to NHS charging, and mistrust and limited knowledge of the UK health and social care system. These barriers leave many people unable to access care toward the end of their lives. Conclusion: To advocate for and provide compassionate palliative and end-of-life care for people with uncertain immigration status, there is need for more legal literacy, with training around people's entitlement to care and support, as well as easier access to specialist legal advice.

Palliative care, homelessness and restricted or uncertain immigration status Most research from the UK about access to support at the end of life for people who are homeless has looked at the experiences of people who are staying in hostels or temporary accommodation. People that are not UK nationals are not entitled to the benefit which pays for hostel or temporary accommodation. There is a group of people in the UK who are very unwell, who are homeless and are not able to access hostel accommodation due to their immigration status. This project explored the experiences of this group around access to palliative care. We spoke to professionals from health and social care services, charities and local councils and people who are in this situation themselves. Hospice staff were also surveyed to see if they had experience of supporting people in this situation. The survey showed that hospices are not currently supporting many people with restricted or uncertain immigration status who are homeless, and that they have limited training around supporting people in this situation. In the interviews and focus groups, opinions were heard about challenges to palliative care support for people with uncertain or restricted immigration status who were experiencing homelessness. Professionals described how it can be hard to obtain support from local authorities, and also understanding rules about who has to pay to receive NHS care. People with uncertain or restricted immigration status who were also homeless did not always know how to access the UK health and social care system and had negative experiences of doing so in the past. As a result, many people are unable to access care towards the end of their lives. To provide compassionate palliative and end-of-life care for people with uncertain immigration status, there is need for more legal literacy, with training around people's entitlement to care and support, as well as easier access to specialist legal advice.

Lessons from relatives: C4 photosynthesis enhances CO2 assimilation during the low-light phase of fluctuations.

Despite the global importance of species with C4 photosynthesis, there is a lack of consensus regarding C4 performance under fluctuating light. Contrasting hypotheses and experimental evidence suggest that C4 photosynthesis is either less or more efficient in fixing carbon under fluctuating light than the ancestral C3 form. Two main issues have been identified that may underly the lack of consensus: neglect of evolutionary distance between selected C3 and C4 species and use of contrasting fluctuating light treatments. To circumvent these issues, we measured photosynthetic responses to fluctuating light across 3 independent phylogenetically controlled comparisons between C3 and C4 species from Alloteropsis, Flaveria, and Cleome genera under 21% and 2% O2. Leaves were subjected to repetitive stepwise changes in light intensity (800 and 100 µmol m-2 s-1 photon flux density) with 3 contrasting durations: 6, 30, and 300 s. These experiments reconciled the opposing results found across previous studies and showed that (i) stimulation of CO2 assimilation in C4 species during the low-light phase was both stronger and more sustained than in C3 species; (ii) CO2 assimilation patterns during the high-light phase could be attributable to species or C4 subtype differences rather than photosynthetic pathway; and (iii) the duration of each light step in the fluctuation regime can strongly influence experimental outcomes.

Corrigendum: Activation of CO2 assimilation during photosynthetic induction is slower in C4 than in C3 photosynthesis in three phylogenetically controlled experiments.

[This corrects the article DOI: 10.3389/fpls.2022.1091115.].

Can we improve the chilling tolerance of maize photosynthesis through breeding?

Chilling tolerance is necessary for crops to thrive in temperate regions where cold snaps and lower baseline temperatures place limits on life processes; this is particularly true for crops of tropical origin such as maize. Photosynthesis is often adversely affected by chilling stress, yet the maintenance of photosynthesis is essential for healthy growth and development, and most crucially for yield. In this review, we describe the physiological basis for enhancing chilling tolerance of photosynthesis in maize by examining nine key responses to chilling stress. We synthesize current knowledge of genetic variation for photosynthetic chilling tolerance in maize with respect to each of these traits and summarize the extent to which genetic mapping and candidate genes have been used to understand the genomic regions underpinning chilling tolerance. Finally, we provide perspectives on the future of breeding for photosynthetic chilling tolerance in maize. We advocate for holistic and high-throughput approaches to screen for chilling tolerance of photosynthesis in research and breeding programmes in order to develop resilient crops for the future.

Activation of CO2 assimilation during photosynthetic induction is slower in C4 than in C3 photosynthesis in three phylogenetically controlled experiments.

Introduction: Despite their importance for the global carbon cycle and crop production, species with C4 photosynthesis are still somewhat understudied relative to C3 species. Although the benefits of the C4 carbon concentrating mechanism are readily observable under optimal steady state conditions, it is less clear how the presence of C4 affects activation of CO2 assimilation during photosynthetic induction. Methods: In this study we aimed to characterise differences between C4 and C3 photosynthetic induction responses by analysing steady state photosynthesis and photosynthetic induction in three phylogenetically linked pairs of C3 and C4 species from Alloteropsis, Flaveria, and Cleome genera. Experiments were conducted both at 21% and 2% O2 to evaluate the role of photorespiration during photosynthetic induction. Results: Our results confirm C4 species have slower activation of CO2 assimilation during photosynthetic induction than C3 species, but the apparent mechanism behind these differences varied between genera. Incomplete suppression of photorespiration was found to impact photosynthetic induction significantly in C4 Flaveria bidentis, whereas in the Cleome and Alloteropsis C4 species, delayed activation of the C3 cycle appeared to limit induction and a potentially supporting role for photorespiration was also identified. Discussion: The sheer variation in photosynthetic induction responses observed in our limited sample of species highlights the importance of controlling for evolutionary distance when comparing C3 and C4 photosynthetic pathways.

Detection of the metabolic response to drought stress using hyperspectral reflectance.

Drought is the most important limitation on crop yield. Understanding and detecting drought stress in crops is vital for improving water use efficiency through effective breeding and management. Leaf reflectance spectroscopy offers a rapid, non-destructive alternative to traditional techniques for measuring plant traits involved in a drought response. We measured drought stress in six glasshouse-grown agronomic species using physiological, biochemical, and spectral data. In contrast to physiological traits, leaf metabolite concentrations revealed drought stress before it was visible to the naked eye. We used full-spectrum leaf reflectance data to predict metabolite concentrations using partial least-squares regression, with validation R2 values of 0.49-0.87. We show for the first time that spectroscopy may be used for the quantitative estimation of proline and abscisic acid, demonstrating the first use of hyperspectral data to detect a phytohormone. We used linear discriminant analysis and partial least squares discriminant analysis to differentiate between watered plants and those subjected to drought based on measured traits (accuracy: 71%) and raw spectral data (66%). Finally, we validated our glasshouse-developed models in an independent field trial. We demonstrate that spectroscopy can detect drought stress via underlying biochemical changes, before visual differences occur, representing a powerful advance for measuring limitations on yield.

A best-practice guide to predicting plant traits from leaf-level hyperspectral data using partial least squares regression.

Partial least squares regression (PLSR) modelling is a statistical technique for correlating datasets, and involves the fitting of a linear regression between two matrices. One application of PLSR enables leaf traits to be estimated from hyperspectral optical reflectance data, facilitating rapid, high-throughput, non-destructive plant phenotyping. This technique is of interest and importance in a wide range of contexts including crop breeding and ecosystem monitoring. The lack of a consensus in the literature on how to perform PLSR means that interpreting model results can be challenging, applying existing models to novel datasets can be impossible, and unknown or undisclosed assumptions can lead to incorrect or spurious predictions. We address this lack of consensus by proposing best practices for using PLSR to predict plant traits from leaf-level hyperspectral data, including a discussion of when PLSR is applicable, and recommendations for data collection. We provide a tutorial to demonstrate how to develop a PLSR model, in the form of an R script accompanying this manuscript. This practical guide will assist all those interpreting and using PLSR models to predict leaf traits from spectral data, and advocates for a unified approach to using PLSR for predicting traits from spectra in the plant sciences.

Source:sink imbalance detected with leaf- and canopy-level spectroscopy in a field-grown crop.

The finely tuned balance between sources and sinks determines plant resource partitioning and regulates growth and development. Understanding and measuring metabolic indicators of source or sink limitation forms a vital part of global efforts to increase crop yield for future food security. We measured metabolic profiles of Cucurbita pepo (zucchini) grown in the field under carbon sink limitation and control conditions. We demonstrate that these profiles can be measured non-destructively using hyperspectral reflectance at both leaf and canopy scales. Total non-structural carbohydrates (TNC) increased 82% in sink-limited plants; leaf mass per unit area (LMA) increased 38% and free amino acids increased 22%. Partial least-squares regression (PLSR) models link these measured functional traits with reflectance data, enabling high-throughput estimation of traits comprising the sink limitation response. Leaf- and canopy-scale models for TNC had R2 values of 0.93 and 0.64 and %RMSE of 13 and 38%, respectively. For LMA, R2 values were 0.91 and 0.60 and %RMSE 7 and 14%; for free amino acids, R2 was 0.53 and 0.21 with %RMSE 20 and 26%. Remote sensing can enable accurate, rapid detection of sink limitation in the field at the leaf and canopy scale, greatly expanding our ability to understand and measure metabolic responses to stress.

Seasonal trends in photosynthesis and leaf traits in scarlet oak.

Understanding seasonal variation in photosynthesis is important for understanding and modeling plant productivity. Here, we used shotgun sampling to examine physiological, structural and spectral leaf traits of upper canopy, sun-exposed leaves in Quercus coccinea Münchh (scarlet oak) across the growing season in order to understand seasonal trends, explore the mechanisms underpinning physiological change and investigate the impact of extrapolating measurements from a single date to the whole season. We tested the hypothesis that photosynthetic rates and capacities would peak at the summer solstice, i.e., at the time of peak photoperiod. Contrary to expectations, our results reveal a late-season peak in both photosynthetic capacity and rate before the expected sharp decrease at the start of senescence. This late-season maximum occurred after the higher summer temperatures and vapor pressure deficit and was correlated with the recovery of leaf water content and increased stomatal conductance. We modeled photosynthesis at the top of the canopy and found that the simulated results closely tracked the maximum carboxylation capacity of Rubisco. For both photosynthetic capacity and modeled top-of-canopy photosynthesis, the maximum value was therefore not observed at the summer solstice. Rather, in each case, the measurements at and around the solstice were close to the overall seasonal mean, with values later in the season leading to deviations from the mean by up to 41 and 52%, respectively. Overall, we found that the expected Gaussian pattern of photosynthesis was not observed. We conclude that an understanding of species- and environment-specific changes in photosynthesis across the season is essential for correct estimation of seasonal photosynthetic capacity.

Identification of Quantitative Trait Loci Relating to Flowering Time, Flag Leaf and Awn Characteristics in a Novel Triticum dicoccum Mapping Population.

Tetraploid landraces of wheat harbour genetic diversity that could be introgressed into modern bread wheat with the aid of marker-assisted selection to address the genetic diversity bottleneck in the breeding genepool. A novel bi-parental Triticum turgidum ssp. dicoccum Schrank mapping population was created from a cross between two landrace accessions differing for multiple physiological traits. The population was phenotyped for traits hypothesised to be proxies for characteristics associated with improved photosynthesis or drought tolerance, including flowering time, awn length, flag leaf length and width, and stomatal and trichome density. The mapping individuals and parents were genotyped with the 35K Wheat Breeders' single nucleotide polymorphism (SNP) array. A genetic linkage map was constructed from 104 F4 individuals, consisting of 2066 SNPs with a total length of 3295 cM and an average spacing of 1.6 cM. Using the population, 10 quantitative trait loci (QTLs) for five traits were identified in two years of trials. Three consistent QTLs were identified over both trials for awn length, flowering time and flag leaf width, on chromosomes 4A, 7B and 5B, respectively. The awn length and flowering time QTLs correspond with the major loci Hd and Vrn-B3, respectively. The identified marker-trait associations could be developed for marker-assisted selection, to aid the introgression of diversity from a tetraploid source into modern wheat for potential physiological trait improvement.

The "one-point method" for estimating maximum carboxylation capacity of photosynthesis: A cautionary tale.

The maximum carboxylation capacity of Rubisco, Vc,max , is an important photosynthetic parameter that is key to accurate estimation of carbon assimilation. The gold-standard technique for determining Vc,max is to derive Vc,max from the initial slope of an A-Ci curve (the response of photosynthesis, A, to intercellular CO2 concentration, Ci ). Accurate estimates of Vc,max derived from an alternative and rapid "one-point" measurement of photosynthesis could greatly accelerate data collection and model parameterization. We evaluated the practical application of the one-point method in six species measured under standard conditions (saturating irradiance and 400 µmol CO2 mol-1 ) and under conditions that would increase the likelihood for successful estimation of Vc,max : (a) ensuring Rubisco-limited A by measuring at 300 µmol CO2 mol-1 and (b) allowing time for acclimation to saturating irradiance prior to measurement. The one-point method significantly underestimated Vc,max in four of the six species, providing estimates 21%-32% below fitted values. We identified ribulose-1,5-bisphosphate-limited A, light acclimation, and the use of an assumed respiration rate as factors that limited the effective use of the one-point method to accurately estimate Vc,max . We conclude that the one-point method requires a species-specific understanding of its application, is often unsuccessful, and must be used with caution.

Spectroscopy can predict key leaf traits associated with source-sink balance and carbon-nitrogen status.

Approaches that enable high-throughput, non-destructive measurement of plant traits are essential for programs seeking to improve crop yields through physiological breeding. However, many key traits still require measurement using slow, labor-intensive, and destructive approaches. We investigated the potential to retrieve key traits associated with leaf source-sink balance and carbon-nitrogen status from leaf optical properties. Structural and biochemical traits and leaf reflectance (500-2400 nm) of eight crop species were measured and used to develop predictive 'spectra-trait' models using partial least squares regression. Independent validation data demonstrated that the models achieved very high predictive power for C, N, C:N ratio, leaf mass per area, water content, and protein content (R2>0.85), good predictive capability for starch, sucrose, glucose, and free amino acids (R2=0.58-0.80), and some predictive capability for nitrate (R2=0.51) and fructose (R2=0.44). Our spectra-trait models were developed to cover the trait space associated with food or biofuel crop plants and can therefore be applied in a broad range of phenotyping studies.

Nutrient sink limitation constrains growth in two barley species with contrasting growth strategies.

Mineral nutrients exert important limitations on plant growth. Growth is limited by the nutrient source when it is constrained by nutrient availability and uptake, which may simultaneously limit investment in photosynthetic proteins, leading to carbon source limitation. However, growth may also be limited by nutrient utilization in sink tissue. The relative importance of these processes is contested, with crop and vegetation models typically assuming source limitations of carbon and mineral nutrients (especially nitrogen). This study compared the importance of source and sink limitation on growth in a slower-growing wild perennial barley (Hordeum bulbosum) and a faster-growing domesticated annual barley (Hordeum vulgare), by applying a mineral nutrient treatment and measuring nitrogen uptake, growth, allocation, and carbon partitioning. We found that nitrogen uptake, growth, tillering, shoot allocation, and nitrogen storage were restricted by low nutrient treatments. Multiple lines of evidence suggest that low nutrient levels do not limit growth via carbon acquisition: (a) Carbohydrate storage does not increase at high nutrient levels. (b) Ratio of free amino acids to sucrose increases at high nutrient levels. (c) Shoot allocation increases at high nutrient levels. These data indicate that barley productivity is limited by the capacity for nutrient use in growth. Models must explicitly account for sink processes in order to properly simulate this mineral nutrient limitation of growth.

Carbon source-sink limitations differ between two species with contrasting growth strategies.

Understanding how carbon source and sink strengths limit plant growth is a critical knowledge gap that hinders efforts to maximize crop yield. We investigated how differences in growth rate arise from source-sink limitations, using a model system comparing a fast-growing domesticated annual barley (Hordeum vulgare cv. NFC Tipple) with a slow-growing wild perennial relative (Hordeum bulbosum). Source strength was manipulated by growing plants at sub-ambient and elevated CO2 concentrations ([CO2 ]). Limitations on vegetative growth imposed by source and sink were diagnosed by measuring relative growth rate, developmental plasticity, photosynthesis and major carbon and nitrogen metabolite pools. Growth was sink limited in the annual but source limited in the perennial. RGR and carbon acquisition were higher in the annual, but photosynthesis responded weakly to elevated [CO2 ] indicating that source strength was near maximal at current [CO2 ]. In contrast, photosynthetic rate and sink development responded strongly to elevated [CO2 ] in the perennial, indicating significant source limitation. Sink limitation was avoided in the perennial by high sink plasticity: a marked increase in tillering and root:shoot ratio at elevated [CO2 ], and lower non-structural carbohydrate accumulation. Alleviating sink limitation during vegetative development could be important for maximizing growth of elite cereals under future elevated [CO2 ].

Rights and the reality of healthcare charging in the United Kingdom.

In 2004, the United Kingdom Government withdrew free access to secondary healthcare for certain groups of overseas visitors, including those asylum seekers whose claims had failed but were still living legally in the UK. We argue, as others have previously, that the implementation of the 2004 National Health Service (Charges to Overseas Visitors) (Amendment) Regulations, represents a serious breach of the right to health as envisaged in international law. This placed health care workers in an invidious position of having to identify those entitled to care. We argue that this is not the role of healthcare and that doctors must not allow the denial of healthcare to be used as a tool of immigration policy. We also question the notion that these regulations make economic sense and suggest that they will have a detrimental effect upon public health.

Safety, pharmacokinetics, and effects on cognitive function of multiple doses of GTS-21 in healthy, male volunteers.

This study was designed to determine the safety, tolerability, pharmacokinetics and effects on cognitive function of GTS-21 in healthy, male volunteers. A total of 18 subjects were randomized to GTS-21 (25, 75 and 150 mg) or placebo administered three times daily (first 4 days, once on Day 5) for three, 5-day sessions. GTS-21 was well tolerated up to doses of 450 mg/day, with no clinically significant safety findings. C(max) and the area under the plasma concentration of GTS-21 and the metabolite 4-OH-GTS-21 increased in a dose-related fashion; although considerable intersubject variability occurred, it decreased with continued dosing. GTS-21 showed statistically significant enhancement of three measures of cognitive function (attention, working memory, episodic secondary memory) compared to placebo. A relationship between exposure to GTS-21 and the magnitude of the cognitive response was apparent, with maximal effect approached for doses between 75 and 150 mg three times a day. These data indicate that GTS-21 may represent a novel treatment for dementia.

Globalization, migration and health.

The term 'globalization' describes the integration of economic systems through improved communication, but it also represents increased insecurity for those with few resources--particularly refugees. This article examines why people migrate, their numbers, constraints on their movement and their particular health care needs. Immigrants have much to contribute to their recipient countries, but at some loss to their homelands. Both economically and morally, more liberal immigration policies would be beneficial. Policies towards asylum seekers should not be more restrictive in the aftermath of 11 September 2001 and detention should be the exception rather than the rule. Globalization should be managed so as to improve people's lives throughout the world.