Error propagation through a bayesian network for biomass estimation in neotropical forests

The above-ground biomass (AGB) of tropical forests is a crucial variable for the global ecological problems. It concerns both scientists and decision makers, especially through the recently set carbon market. Estimations of AGB from tree inventories are also a crucial point for the development of new methods of estimation, especially from above (plane, satellite). Tree inventories are the actual material for assessing carbon stocks. They produce a large range of datasets. Some cover small area and give hi-quality information: diameter at breast height (DBH), species Latin names, heights, ... Some datasets cover very large areas but give low-quality information: range of DBH instead of precise measure, family name or even no floristic specification, no heights, ... In addition, some other databases are required, like wood density data and weighted trees. For this study located in French Guiana, we use all of those kinds of datasets. To make correct inferences about biomass stocks and their evolution, it is essential to quantify the uncertainty associated with AGB estimates. It is also essential to answer those two questions: 1- Where does the uncertainty come from, and 2- How does it change with the data quality. To answer those questions, we calculate the AGB with a full hierarchical Bayesian model. It allows us to propagate errors through the model until the final AGB distribution. We can then perform a sensibility analysis, changing the error laws. The error laws are describing the uncertainty associated with every field measure. Both width and shapes may vary. Finally, we discuss the changes in AGB posterior distribution with the changes in error laws and data type. We also give some implication for both previous work and future experiments. (Résumé d'auteur

Stress corrosion crack initiation of Zircaloy-4 cladding tubes in an iodine vapor environment during creep, relaxation, and constant strain rate tests

During accidental power transient conditions with Pellet Cladding Interaction (PCI), the synergistic effect of the stress and strain imposed on the cladding by thermal expansion of the fuel, and corrosion by iodine released as a fission product, may lead to cladding failure by Stress Corrosion Cracking (SCC). In this study, internal pressure tests were conducted on unirradiated cold-worked stress-relieved Zircaloy-4 cladding tubes in an iodine vapor environment. The goal was to investigate the influence of loading type (constant pressure tests, constant circumferential strain rate tests, or constant circumferential strain tests) and test temperature (320, 350, or 380 °C) on iodine-induced stress corrosion cracking (I-SCC). The experimental results obtained with different loading types were consistent with each other. The apparent threshold hoop stress for I-SCC was found to be independent of the test temperature. SEM micrographs of the tested samples showed many pits distributed over the inner surface, which tended to coalesce into large pits in which a microcrack could initiate. A model for the time-to-failure of a cladding tube was developed using finite element simulations of the viscoplastic mechanical behavior of the material and a modified Kachanov's damage growth model. The times-to-failure predicted by this model are consistent with the experimental data

Mechanical behavior of recrystallized Zircaloy-4 under monotonic loading at room temperature: Tests and simplified anisotropic modeling

Mechanical behavior of recrystallized Zircaloy-4 was studied at room temperature in the rolling-transverse plane of a thin sheet. Uniaxial constant elongation rate tests (CERTs) were performed along with creep tests, over a wide range of strain rates. Based on a simplified formulation, different sets of parameters for an anisotropic viscoplastic model were found to fit the stress–strain curves. Notched specimen tensile tests were carried out with a digital image correlation (DIC) technique in order to determine the strain field evolution. From these measurements and the determination of Lankford coefficients, the most consistent model was selected and simulated data were successfully compared with the experimental observations

Marked increase in incidence for bloodstream infections due to Escherichia coli, a side effect of previous antibiotic therapy in the elderly.

We conducted a survey including 3334 bloodstream infections (BSIs) due to E. coli diagnosed in 2005-2014 at a stable cohort of hospitals. Marked increases in incidence were observed for community-acquired (CA) BSIs in patients aged >75 years, CA-BSIs of digestive origin in patients aged 60-74 years, healthcare-associated BSIs, and BSIs associated with ESBL (extended-spectrum B-lactamase)-producing E. coli (ESBLEc). Using MLST, we studied the genetic diversity of 412 BSI isolates recovered during the 2014 survey: 7 major sequence type complexes (STCs) were revealed in phylogenetic group B2, 3 in group A/B1 and 2 in group D. Among the 31 ESBLEc isolates, 1/3 belonged to STC 131. We searched for possible associations between clonal groups, clinical determinants and characteristics of BSIs: isolates from groups B2 (except STC 131) and D were susceptible to antibiotics and associated with BSIs of urinary origin in patients <60 years. STC 131 and group A/B1 isolates were multi-drug resistant and associated with CA-BSIs of digestive origin in patients aged 60-74 with a recent history of antibiotic treatment. STC 131 isolates were associated with HCA-BSIs in patients with recent/present hospitalization in a long-stay unit. We provide a unique population-based picture of the epidemiology of E. coli BSI. The aging nature of the population led to an increase in the number of cases caused by the B2 and D isolates generally implicated in BSIs. In addition, the association of a trend toward increasing rates of gut colonization with multi drug-resistant isolates revealed by the rise in the incidence of BSIs of digestive origin caused by STC 131 and A/B1 (STCs 10, 23, and 155) isolates, and a significant increase in the frequency of BSIs in elderly patients with recent antibiotic treatment suggested that antibiotic use may have contributed to the growing incidence of BSI

Bounded Expectations: Resource Analysis for Probabilistic Programs

This paper presents a new static analysis for deriving upper bounds on the expected resource consumption of probabilistic programs. The analysis is fully automatic and derives symbolic bounds that are multivariate polynomials of the inputs. The new technique combines manual state-of-the-art reasoning techniques for probabilistic programs with an effective method for automatic resource-bound analysis of deterministic programs. It can be seen as both, an extension of automatic amortized resource analysis (AARA) to probabilistic programs and an automation of manual reasoning for probabilistic programs that is based on weakest preconditions. As a result, bound inference can be reduced to off-the-shelf LP solving in many cases and automatically-derived bounds can be interactively extended with standard program logics if the automation fails. Building on existing work, the soundness of the analysis is proved with respect to an operational semantics that is based on Markov decision processes. The effectiveness of the technique is demonstrated with a prototype implementation that is used to automatically analyze 39 challenging probabilistic programs and randomized algorithms. Experimental results indicate that the derived constant factors in the bounds are very precise and even optimal for many programs

Stakeholder Perspectives on Randomized Clinical Trials for Children With Poor-Prognosis Cancers

Ensayos clínicos aleatorizados; Niños; CáncerAssaigs clínics aleatoris; Nens; CàncerRandomized clinical trials; Children; CancerImportance In poor-prognosis children’s cancers, new therapies may carry fresh hope for patients and parents. However, there is an absolute requirement for any new therapy to be properly evaluated to fulfill scientific, regulatory, and reimbursement requirements. Randomized clinical trials (RCTs) are considered the gold standard, but no consensus exists on how and when they should be deployed to best meet the needs of all stakeholders. Objective To conduct a multistakeholder meeting to foster a greater shared understanding of perspectives regarding RCTs of new therapies for children with poor-prognosis cancers and develop consensus recommendations on when and how they should be used. Evidence Review During October 2022 and April 2023, 2 structured workshops were convened, bringing together individuals representing the perspectives of patient advocates and academic clinician-researchers, regulators, and health technology assessment bodies. A premeeting briefing document was prepared and circulated to all attendees. During the workshops, selected attendees presented on behalf of each stakeholder group, focused topic discussions were conducted, and each meeting concluded by agreeing on a consensus set of recommendations. Meeting organizers drafted meeting summary reports that were circulated to all attendees, who commented on and revised them as a group to produce final recommendations from the workshops. Findings Though the workshops did not reconcile all stakeholder differences, sufficient areas of agreement enabled a set of conclusions to be drawn, resulting in 8 consensus recommendations: (1) drug development strategies for new therapies, including the role of RCTs, should be established at the time of first-in-child studies; (2) engagement with regulators and health technology assessment bodies about RCT design is crucial; (3) involvement of patient advocates is necessary to ensure that an RCT is patient focused; (4) timing of an RCT is critical to preserve clinical equipoise; (5) use of crossover in an RCT can be of benefit, but with important caveats; (6) end point maturity and overall survival in an RCT may be important for regulatory and health technology assessment approvals; (7) in the absence of an RCT, contemporaneous control cohorts are preferred over historical control cohorts; and (8) quality of life should be captured in all prospective RCTs. Conclusions and Relevance The agreed-upon workshop conclusions provide a basis for key considerations while undertaking future drug development activities for children with poor-prognosis cancers, ensuring that the needs and perspectives of all stakeholders are factored in from the outset.The workshops were organized and conducted by Childhood Cancer International Europe with funding support from operating grant 101083204 from the European Union

An Experimental Study of A Design-driven, Tool-based Development Approach

International audienceDesign-driven software development approaches have long been praised for their many benefits on the development process and the resulting software system. This paper discusses a step towards assessing these benefits by proposing an experimental study that involves a design-driven, tool-based development approach. This study raises various questions including whether a design-driven approach improves software quality and whether the tool-based approach improves productivity. In examining these questions, we explore specific issues such as the approaches that should be involved in the comparison, the metrics that should be used, and the experimental framework that is required

Disparity of turbinal bones in placental mammals

Turbinals are key bony elements of the mammalian nasal cavity, involved in heat and moisture conservation as well as olfaction. While turbinals are well known in some groups, their diversity is poorly understood at the scale of placental mammals, which span 21 orders. Here, we investigated the turbinal bones and associated lamellae for one representative of each extant order of placental mammals. We segmented and isolated each independent turbinal and lamella and found an important diversity of variation in the number of turbinals, as well as their size, and shape. We found that the turbinal count varies widely, from zero in the La Plata dolphin, (Pontoporia blainvillei) to about 110 in the African bush elephant (Loxodonta africana). Multiple turbinal losses and additional gains took place along the phylogeny of placental mammals. Some changes are clearly attributed to ecological adaptation, while others are probably related to phylogenetic inertia. In addition, this work highlights the problem of turbinal nomenclature in some placental orders with numerous and highly complex turbinals, for which homologies are extremely difficult to resolve. Therefore, this work underscores the importance of developmental studies to better clarify turbinal homology and nomenclature and provides a standardized comparative framework for further research

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly