Controls on winter ecosystem respiration in temperate and boreal ecosystems

Winter CO2 fluxes represent an important component of the annual carbon budget in northern ecosystems. Understanding winter respiration processes and their responses to climate change is also central to our ability to assess terrestrial carbon cycle and climate feedbacks in the future. However, the factors influencing the spatial and temporal patterns of winter ecosystem respiration (Reco) of northern ecosystems are poorly understood. For this reason, we analyzed eddy covariance flux data from 57 ecosystem sites ranging from ~35° N to ~70° N. Deciduous forests were characterized by the highest winter Reco rates (0.90 ± 0.39 g C m-2 d-1), when winter is defined as the period during which daily air temperature remains below 0 °C. By contrast, arctic wetlands had the lowest winter Reco rates (0.02 ± 0.02 g C m-2 d-1). Mixed forests, evergreen needle-leaved forests, grasslands, croplands and boreal wetlands were characterized by intermediate winter Reco rates (g C m-2 d-1) of 0.70(±0.33), 0.60(±0.38), 0.62(±0.43), 0.49(±0.22) and 0.27(±0.08), respectively. Our cross site analysis showed that winter air (Tair) and soil (Tsoil) temperature played a dominating role in determining the spatial patterns of winter Reco in both forest and managed ecosystems (grasslands and croplands). Besides temperature, the seasonal amplitude of the leaf area index (LAI), inferred from satellite observation, or growing season gross primary productivity, which we use here as a proxy for the amount of recent carbon available for Reco in the subsequent winter, played a marginal role in winter CO2 emissions from forest ecosystems. We found that winter Reco sensitivity to temperature variation across space (QS) was higher than the one over time (interannual, QT). This can be expected because QS not only accounts for climate gradients across sites but also for (positively correlated) the spatial variability of substrate quantity. Thus, if the models estimate future warming impacts on Reco based on QS rather than QT, this could overestimate the impact of temperature change

Distribution of Pd clusters on ultrathin, epitaxial TiOx films on Pt3Ti(111)

Scanning tunnelling microscopy (STM) was used to investigate the nucleation and growth of palladium clusters on two different, ultrathin, epitaxial, titania films grown on a Pt$_{3}$Ti(111) surface. The first oxide phase, z\u27-TiO$_{χ}$, is anisotropic and consists of parallel stripes separated by trenches. Defects (i.e., oxygen vacancies) in this structure are confined to these trenches and act as nucleation sites. Therefore, the Pd clusters are mostly arranged in unidirectional rows along the trenches, creating a template effect. The second phase, w\u27-TiO$_{χ}$, exhibits a hexagonal, long range, (7 × 7)R21.8°, Moiré-type superstructure with fewer and shallower defects, making the template effect less discernible

Type soundness for dependent object types (DOT)

Scala's type system unifies aspects of ML modules, object-oriented, and functional programming. The Dependent Object Types (DOT) family of calculi has been proposed as a new theoretic foundation for Scala and similar expressive languages. Unfortunately, type soundness has only been established for restricted subsets of DOT. In fact, it has been shown that important Scala features such as type refinement or a subtyping relation with lattice structure break at least one key metatheoretic property such as environment narrowing or invertible subtyping transitivity, which are usually required for a type soundness proof. The main contribution of this paper is to demonstrate how, perhaps surprisingly, even though these properties are lost in their full generality, a rich DOT calculus that includes recursive type refinement and a subtyping lattice with intersection types can still be proved sound. The key insight is that subtyping transitivity only needs to be invertible in code paths executed at run time, with contexts consisting entirely of valid runtime objects, whereas inconsistent subtyping contexts can be permitted for code that is never executed

Is there potential for using beatboxing in supporting laryngectomees?: findings from a public engagement project

This paper outlines key findings from the UCL public engagement project Beatboxing after laryngectomy. The project was a collaboration between Dr Evangelos Himonides from the UCL Institute of Education and Shout at Cancer, the only charity, globally, that implements singing and acting techniques in the voice rehabilitation for laryngectomies. Clinicians, patients with laryngectomies and young people from East London were brought together to explore the role of beatboxing in voice rehabilitation and raise awareness of the difficulties facing those without voice boxes

Navigating VET to university: Students' perceptions of their transition to university study

<p><em>This paper examines preliminary findings from research into the transition experiences of students entering university through a VET pathway. Participants’ responses obtained in an online survey are analysed to explore their perceptions of how their VET background influenced their transition, including their expectations and adjustment to university. Findings indicate that participants are largely experiencing transition as a positive experience, but in particular those who perceived their VET background as very influential on their transition have significantly higher levels of adjustment and fulfilled expectations. The survey is part of a larger research project including focus groups and interviews that will allow a deeper analysis of students’ experiences. The research also aims to contribute to a deeper conceptual understanding of the transition process. </em></p><p> </p