When do plant hydraulics matter in terrestrial biosphere modelling?

The ascent of water from the soil to the leaves of vascular plants, described by the study of plant hydraulics, regulates ecosystem responses to environmental forcing and recovery from stress periods. Several approaches to model plant hydraulics have been proposed. In this study, we introduce four different versions of plant hydraulics representations in the terrestrial biosphere model T&C to understand the significance of plant hydraulics to ecosystem functioning. We tested representations of plant hydraulics, investigating plant water capacitance, and long-term xylem damages following drought. The four models we tested were a combination of representations including or neglecting capacitance and including or neglecting xylem damage legacies. Using the models at six case studies spanning semiarid to tropical ecosystems, we quantify how plant xylem flow, plant water storage and long-term xylem damage can modulate overall water and carbon dynamics across multiple time scales. We show that as drought develops, models with plant hydraulics predict a slower onset of plant water stress, and a diurnal variability of water and carbon fluxes closer to observations. Plant water storage was found to be particularly important for the diurnal dynamics of water and carbon fluxes, with models that include plant water capacitance yielding better results. Models including permanent damage to conducting plant tissues show an additional significant drought legacy effect, limiting plant productivity during the recovery phase following major droughts. However, when considering ecosystem responses to the observed climate variability, plant hydraulic modules alone cannot significantly improve the overall model performance, even though they reproduce more realistic water and carbon dynamics. This opens new avenues for model development, explicitly linking plant hydraulics with additional ecosystem processes, such as plant phenology and improved carbon allocation algorithms.

Economic valuation of temperature-related mortality attributed to urban heat islands in European cities.

As the climate warms, increasing heat-related health risks are expected, and can be exacerbated by the urban heat island (UHI) effect. UHIs can also offer protection against cold weather, but a clear quantification of their impacts on human health across diverse cities and seasons is still being explored. Here we provide a 500 m resolution assessment of mortality risks associated with UHIs for 85 European cities in 2015-2017. Acute impacts are found during heat extremes, with a 45% median increase in mortality risk associated with UHI, compared to a 7% decrease during cold extremes. However, protracted cold seasons result in greater integrated protective effects. On average, UHI-induced heat-/cold-related mortality is associated with economic impacts of €192/€ - 314 per adult urban inhabitant per year in Europe, comparable to air pollution and transit costs. These findings urge strategies aimed at designing healthier cities to consider the seasonality of UHI impacts, and to account for social costs, their controlling factors, and intra-urban variability.

Machine Learning in Meningioma MRI: Past to Present. A Narrative Review.

Meningioma is one of the most frequent primary central nervous system tumors. While magnetic resonance imaging (MRI), is the standard radiologic technique for provisional diagnosis and surveillance of meningioma, it nevertheless lacks the prima facie capacity in determining meningioma biological aggressiveness, growth, and recurrence potential. An increasing body of evidence highlights the potential of machine learning and radiomics in improving the consistency and productivity and in providing novel diagnostic, treatment, and prognostic modalities in neuroncology imaging. The aim of the present article is to review the evolution and progress of approaches utilizing machine learning in meningioma MRI-based sementation, diagnosis, grading, and prognosis. We provide a historical perspective on original research on meningioma spanning over two decades and highlight recent studies indicating the feasibility of pertinent approaches, including deep learning in addressing several clinically challenging aspects. We indicate the limitations of previous research designs and resources and propose future directions by highlighting areas of research that remain largely unexplored. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 2.

Rainfall manipulation experiments as simulated by terrestrial biosphere models: Where do we stand?

Changes in rainfall amounts and patterns have been observed and are expected to continue in the near future with potentially significant ecological and societal consequences. Modelling vegetation responses to changes in rainfall is thus crucial to project water and carbon cycles in the future. In this study, we present the results of a new model-data intercomparison project, where we tested the ability of 10 terrestrial biosphere models to reproduce the observed sensitivity of ecosystem productivity to rainfall changes at 10 sites across the globe, in nine of which, rainfall exclusion and/or irrigation experiments had been performed. The key results are as follows: (a) Inter-model variation is generally large and model agreement varies with timescales. In severely water-limited sites, models only agree on the interannual variability of evapotranspiration and to a smaller extent on gross primary productivity. In more mesic sites, model agreement for both water and carbon fluxes is typically higher on fine (daily-monthly) timescales and reduces on longer (seasonal-annual) scales. (b) Models on average overestimate the relationship between ecosystem productivity and mean rainfall amounts across sites (in space) and have a low capacity in reproducing the temporal (interannual) sensitivity of vegetation productivity to annual rainfall at a given site, even though observation uncertainty is comparable to inter-model variability. (c) Most models reproduced the sign of the observed patterns in productivity changes in rainfall manipulation experiments but had a low capacity in reproducing the observed magnitude of productivity changes. Models better reproduced the observed productivity responses due to rainfall exclusion than addition. (d) All models attribute ecosystem productivity changes to the intensity of vegetation stress and peak leaf area, whereas the impact of the change in growing season length is negligible. The relative contribution of the peak leaf area and vegetation stress intensity was highly variable among models.

Extreme lateral lumbar interbody fusion (XLIF) in the management of degenerative scoliosis: a retrospective case series.

BACKGROUND: Surgical treatment of adult degenerative scoliosis (DS) always remains a challenge and often necessitates complex multilevel surgery via traditional open approaches. However, the severity of the procedure, in association with the fact that many of these patients are at an advanced age with several comorbidities, results in high rate of complications. Therefore, during the last decade, minimally invasive procedures have gained a place in the treatment of this pathology. Our aim is to determine the safety and efficacy of extra lateral lumbar interbody fusion (XLIF) with or without supplemented instrumentation in the treatment of DS. METHODS: In a retrospective case series study, we reviewed the files of patients who underwent XLIF in our Hospital between 2008 and 2017. We recorded the patients' demographic characteristics, clinical parameters such as back-pain [visual analogue scale (VAS)] and back-related disability [Oswestry Disability Index (ODI)], as well as radiological parameters including the Cobb angle. Comparison of the before and after results were performed with the t-test and Chi-square test, where appropriate. RESULTS: Twelve patients fulfilled the eligibility criteria of our study. All patients were female, with a mean age of 64.5 years (SD =7.8 years) and 28 months (SD =13 months) follow-up. The XLIF decreased the pain intensity by 4.66 cm (SD =1.23 cm), and improved the back-related disability by 26% (SD =8.35%) in the ODI scale at the 6-month follow-up. Similarly, scoliosis improved by an average of 11.5° (SD =7°) and lordosis changed by an average of 13.5° (SD =10.86°). All changes were statistically significant. There were three complications, two patients presented meralgia paresthetica, which resolved spontaneously in 3 months, and in one patient occurred an intraoperative bowel perforation treated with bowel anastomosis. CONCLUSIONS: XLIF is a feasible and efficient alternative in the treatment of DS. It can be the treatment of choice in elderly patients in whom comorbidities increase the perioperative risk of complications.

Collagen type-I A2 gene polymorphisms and susceptibility to intracranial aneurysms: a meta-analysis of genetic association studies.

BACKGROUND: The development, evolution and rupture of intracranial aneurysms are in part related to genetic factors. The role of collagen type-I a2 genetic polymorphisms has not been clarified yet. MATERIAL AND METHODS: A meta-analysis was realized by means of a genotype model-fitting process (allele contrast, recessive, dominant, additive and co-dominant), and a model-free approach using the generalized odds ratio. The latter was assessed in association to the degree of dominance (h-index). RESULTS: No statistically significant association was documented between EX28 G>C collagen type-I a2 variant and intracranial aneurysms (generalized odds ratio = 1.23, 95% confidence interval = 0.57, 2.63). Significant associations between INT46 T>G collagen type I a2 variant and intracranial aneurysms were documented in three models, the dominant [0.52 (0.38, 069)], the co-dominant [0.50 (0.32, 0.78)] and the allele contrast models [0.63 (0.49, 0.82)]. The generalized odds ratio was estimated to be as high as 1.94 (1.23, 3.06). The degree of dominance (h-index = -1.54) indicated that the TG genotype was characterized by lower risk of developing intracranial aneurysms compared to the TT genotype. CONCLUSIONS: The available literature data demonstrated that there is no association of collagen type-(2a) and intracranial aneurysms, through EX28 G>C (rs42524) polymorphism according to the model-fitting process and the model-free approach. Regarding the INT46 T>G (rs2621215) polymorphisms, the latter models indicated that there could be a protective effect of the G-allele against the development of intracranial aneurysms. However, the majority of studies are from East Asia, therefore the results are applicable primarily to that patient population.

Partitioning direct and indirect effects reveals the response of water-limited ecosystems to elevated CO2.

Increasing concentrations of atmospheric carbon dioxide are expected to affect carbon assimilation and evapotranspiration (ET), ultimately driving changes in plant growth, hydrology, and the global carbon balance. Direct leaf biochemical effects have been widely investigated, whereas indirect effects, although documented, elude explicit quantification in experiments. Here, we used a mechanistic model to investigate the relative contributions of direct (through carbon assimilation) and indirect (via soil moisture savings due to stomatal closure, and changes in leaf area index) effects of elevated CO2 across a variety of ecosystems. We specifically determined which ecosystems and climatic conditions maximize the indirect effects of elevated CO2 The simulations suggest that the indirect effects of elevated CO2 on net primary productivity are large and variable, ranging from less than 10% to more than 100% of the size of direct effects. For ET, indirect effects were, on average, 65% of the size of direct effects. Indirect effects tended to be considerably larger in water-limited ecosystems. As a consequence, the total CO2 effect had a significant, inverse relationship with the wetness index and was directly related to vapor pressure deficit. These results have major implications for our understanding of the CO2 response of ecosystems and for global projections of CO2 fertilization, because, although direct effects are typically understood and easily reproducible in models, simulations of indirect effects are far more challenging and difficult to constrain. Our findings also provide an explanation for the discrepancies between experiments in the total CO2 effect on net primary productivity.

A giant, free-floating mass in the left atrium in a patient with atrial fibrillation.

A large intracardiac mass is a rare condition and one with an extremely high risk of haemodynamic and embolic complications. Urgent surgical excision is the treatment of choice, and the histological examination reveals the exact nature of the mass, usually a myxoma or a thrombus. We present the case of an 80-year-old woman, with a history of atrial fibrillation, who was admitted because of a seriously impaired level of consciousness, and fever. A large cerebral infarct and a urinary tract infarction were diagnosed. On the transthoracic echocardiogram a giant, free-floating mass was detected in the left atrium, transiently obstructing the mitral valve orifice. Based on the features of the mass and patient's history, it was considered more likely to be a thrombus rather than a tumour. Given the patient's extremely unfavourable neurological status, cardiac surgery was considered to be contraindicated and the patient was administered unfractionated heparin intravenously. Unfortunately, after a few hours the patient suffered a cardiac arrest and died.