Modeling stomatal conductance in the earth system: linking leaf water-use efficiency and water transport along the soil–plant–atmosphere continuum

The Ball–Berry stomatal conductance model is commonly used in earth system models to simulate biotic regulation of evapotranspiration. However, the dependence of stomatal conductance (<i>g</i>_s) on vapor pressure deficit (<i>D</i>_s) and soil moisture must be empirically parameterized. We evaluated the Ball–Berry model used in the Community Land Model version 4.5 (CLM4.5) and an alternative stomatal conductance model that links leaf gas exchange, plant hydraulic constraints, and the soil–plant–atmosphere continuum (SPA). The SPA model simulates stomatal conductance numerically by (1) optimizing photosynthetic carbon gain per unit water loss while (2) constraining stomatal opening to prevent leaf water potential from dropping below a critical minimum. We evaluated two optimization algorithms: intrinsic water-use efficiency (&Delta;<i>A</i>_n /&Delta;<i>g</i>_s, the marginal carbon gain of stomatal opening) and water-use efficiency (&Delta;<i>A</i>_n /&Delta;<i>E</i>_l, the marginal carbon gain of transpiration water loss). We implemented the stomatal models in a multi-layer plant canopy model to resolve profiles of gas exchange, leaf water potential, and plant hydraulics within the canopy, and evaluated the simulations using leaf analyses, eddy covariance fluxes at six forest sites, and parameter sensitivity analyses. The primary differences among stomatal models relate to soil moisture stress and vapor pressure deficit responses. Without soil moisture stress, the performance of the SPA stomatal model was comparable to or slightly better than the CLM Ball–Berry model in flux tower simulations, but was significantly better than the CLM Ball–Berry model when there was soil moisture stress. Functional dependence of <i>g</i>_s on soil moisture emerged from water flow along the soil-to-leaf pathway rather than being imposed a priori, as in the CLM Ball–Berry model. Similar functional dependence of <i>g</i>_s on <i>D</i>_s emerged from the &Delta;<i>A</i>_n/&Delta;<i>E</i>_l optimization, but not the &Delta;<i>A</i>_n /<i>g</i>_s optimization. Two parameters (stomatal efficiency and root hydraulic conductivity) minimized errors with the SPA stomatal model. The critical stomatal efficiency for optimization (&iota;) gave results consistent with relationships between maximum <i>A</i>_n and <i>g</i>_s seen in leaf trait data sets and is related to the slope (<i>g</i>₁) of the Ball–Berry model. Root hydraulic conductivity (<i>R</i>_r^*) was consistent with estimates from literature surveys. The two central concepts embodied in the SPA stomatal model, that plants account for both water-use efficiency and for hydraulic safety in regulating stomatal conductance, imply a notion of optimal plant strategies and provide testable model hypotheses, rather than empirical descriptions of plant behavior

Using Data Linkage to Investigate Inconsistent Reporting of Self-Harm and Questionnaire Non-Response

The objective of this study was to examine agreement between self-reported and medically recorded self-harm, and investigate whether the prevalence of self-harm differs in questionnaire responders vs. non-responders. A total of 4,810 participants from the Avon Longitudinal Study of Parents and Children (ALSPAC) completed a self-harm questionnaire at age 16 years. Data from consenting participants were linked to medical records (number available for analyses ranges from 205-3,027). The prevalence of self-harm leading to hospital admission was somewhat higher in questionnaire non-responders than responders (2.0 vs. 1.2%). Hospital attendance with self-harm was under-reported on the questionnaire. One third reported self-harm inconsistently over time; inconsistent reporters were less likely to have depression and fewer had self-harmed with suicidal intent. Self-harm prevalence estimates derived from self-report may be underestimated; more accurate figures may come from combining data from multiple sources

Does attentional dysfunction and thalamic atrophy predict decline in dementia with Lewy bodies?

INTRODUCTION: To evaluate the clinical characteristics of DLB subjects who died within 1 year of assessment compared to those who survived and investigate their patterns of in vivo regional thalamic atrophy using structural MRI. METHODS: Seventy subjects (35 DLB, 35 aged controls) underwent 3 T T1-weighted MR scanning as well as clinical and cognitive assessments, including a computerised assessment of attention. All subjects were contacted after 12 months for reassessment. For both hemispheres, using FSL FIRST, the thalamus was automatically segmented followed by inter-subject vertex-wise analyses involving group comparisons and behavioural correlates. RESULTS: There was significant bilateral atrophy in the ventral-dorsal and pulvinar regions in DLB relative to controls (pcorrected < 0.05). The DLB group was then re-categorised based on 12-month mortality data: DLB-a (n = 26) and DLB-d (n = 9) (a = alive, d = death within 12 months of study assessment). Compared to controls, significant attentional dysfunction and bilateral atrophy of the pulvinar, ventral and dorsal nuclei were observed in DLB-d (pcorrected < 0.05), whereas in DLB-a, atrophy was far less extensive. CONCLUSIONS: Distinct patterns of thalamic atrophy occur in DLB that may relate to the attentional dysfunction and cognitive fluctuations that characterise this disorder. Relative to controls, the extent of attentional impairment and pattern of thalamic degeneration differ in those patients who died within 12 months of assessment, despite having an otherwise similar level of dementia severity. These findings may provide insight into the neurobiological changes underpinning important clinical characteristics and disease heterogeneity

Decarbonising and Diversifying Defence in the US and the UK: A Workers’ Enquiry for a Just Transition: Full Report

Introduction: p.4

Trichomonad parasite infection in four species of Columbidae in the UK

Trichomonas gallinae is an emerging pathogen in wild birds, linked to recent declines in finch (Fringillidae) populations across Europe. Globally, the main hosts for this parasite are species of Columbidae (doves and pigeons); here we carry out the first investigation into the presence and incidence of Trichomonas in four species of Columbidae in the UK, through live sampling of wild-caught birds and subsequent PCR. We report the first knownUKcases of Trichomonas infection in 86% of European Turtle Doves Streptopelia turtur sampled, along with 86% of Eurasian Collared Doves Streptopelia decaocto, 47% of Woodpigeons Columba palumbus and 40% of Stock Doves Columba oenas. Birds were more likely to be infected if the farm provided supplementary food for gamebirds. We found three strains of T. gallinae and one strain clustering within the Trichomonas tenax clade, not previously associated with avian hosts in the UK. One T. gallinae strain was identical at the ITS/5.8S/ITS2 ribosomal region to that responsible for the finch trichomonosis epizootic. We highlight the importance of increasing our knowledge of the diversity and ecological implications of Trichomonas parasites in order further to understand the sub-clinical impacts of parasite infection

Global longitudinal strain by feature tracking cardiovascular MRI predicts mortality in patients with end stage kidney disease

Background: Patients with end-stage kidney disease (ESKD) are at increased risk premature death, with cardiovascular disease being the predominant mode of death. We hypothesized that left ventricular global longitudinal strain (LV-GLS) measured by feature tracking cardiovascular magnetic resonance imaging (CMR) would be associated with all-cause mortality in patients with ESKD. Methods: A pooled analysis of CMR studies in patients with ESKD acquired within a single centre between 2002 and 2016 was carried out. CMR parameters including left ventricular ejection fraction (LVEF), LV mass index (LVMI), left atrial emptying fraction (LAEF) and LV-GLS were measured. We tested independent associations of CMR parameters with survival using a multivariable Cox model. Results: Among 215 patients (mean age: 54 years, 62% male), mortality was 53% over 5.0 years median follow-up. The median LVEF was 64.7% (IQR 58.5, 70.0) and median LV-GLS was -15.3% (-17.24, -13.6). While 90% of patients had preserved LVEF (&gt;50%), 58% of this group had abnormal LVGLS (&gt;-16%). On multivariable Cox regression, age (HR: 1.04, 95%CI: 1.02-1.05), future-renal transplant (HR 0.29 95%CI: 0.17-0.47), LAEF (HR: 0.98, 95%CI: 0.96-1.00) and LV-GLS (HR: 1.08, 95%CI: 1.01-1.16) were independently associated with mortality. Conclusions: In this cohort of patients with ESKD, LV-GLS on feature tracking CMR and LAEF were associated with all-cause mortality, independent of baseline clinical variables and future renal transplantation. This effect was present even when &gt;90% of the cohort had normal left ventricular ejection fraction (LVEF). Using LV-GLS, instead of LVEF, to diagnose cardiac dysfunction in patients with ESKD could result in a major advance in our understanding of cardiovascular disease in ESKD

Threats posed to conservation by media misinformation

Media coverage of trophy hunting highlights the potential for misinformation to enter public and political debates on conservation issues. We argue that misinformation should be a major concern for all involved in conservation

The radio source count at 93.2 GHz from observations of 9C sources using AMI and CARMA

We present results from follow-up observations of a sample of 80 radio sources, originally detected as part of the 15.2-GHz Ninth Cambridge (9C) survey. The observations were carried out, close to simultaneously, at two frequencies: 15.7 GHz, using the Arcminute Microkelvin Imager (AMI) Large Array, and 93.2 GHz, using the Combined Array for Research in Millimeter-wave Astronomy (CARMA). There is currently little direct information on the 90-GHz-band source count for S ≲ 1 Jy. However, we have used the measured 15.7-to-93.2-GHz spectral-index distribution and 9C source count to predict the differential source count at 93.2 GHz as 26 ± 4(S/Jy)^(−2.15) Jy^(−1) sr^(−1); our projection is estimated to be most accurate for 10 ≲ S ≲ 100 mJy. Our estimated differential count is more than twice the 90-GHz prediction made by Waldram et al.; we believe that this discrepancy is because the measured 43-GHz flux densities used in making their prediction were too low. Similarly, our prediction is significantly higher than that of Sadler et al. at 95 GHz. Since our spectral-index distribution is similar to the 20-to-95-GHz distribution measured by Sadler et al. and used in making their prediction, we believe that the difference is almost entirely attributable to the dissimilarity in the lower frequency counts used in making the estimates