10 research outputs found
Optical modeling of the Jefferson Laboratory IR demo FEL
The Thomas Jefferson National Accelerator Facility (Jefferson Lab) is in the process of building a 1 kW free-electron laser operates at 3 microns. The details of the accelerator driver are given in other papers in these proceedings. The optical cavity consists of a near-concentric resonator with transmissive outcoupling. Though several free-electron lasers have used similar designs, they have not had to confront the high average-power loading present in this laser. It is useful to know the limits of this type of optical cavity design. The optical system of the laser has been modeled using the commercial code GLAD{reg_sign} by using a Beer`s-law region to mimic the FEL interaction. The effects of mirror heating have been calculated and compared with analytical treatments. The magnitude of the distortion for several materials and wave-lengths has been estimated. The model developed here allows one to quickly determine whether the mirror substrates and coatings are adequate for operation at a given optical power level once the absorption of the coatings, substrate, and transmission are known. Results of calculations of the maximum power level expected using several different sets of mirrors will be presented. Measurements of the distortion in calcium fluoride from absorption of carbon dioxide laser light are planned to benchmark the simulations. Multimode simulations using the code ELIXER have been carried out to characterize the saturated optical mode quality. The results will be presented
TRY plant trait database – enhanced coverage and open access
Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
Global variability in leaf respiration in relation to climate, plant functional types and leaf traits
• Leaf dark respiration (Rdark) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of Rdark and associated leaf traits.
• Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixed-effects models were used to disentangle sources of variation in Rdark.
• Area-based Rdark at the prevailing average daily growth temperature (T) of each site increased only twofold from the Arctic to the tropics, despite a 20°C increase in growing T (8–28°C). By contrast, Rdark at a standard T (25°C, Rdark25) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher Rdark25 at a given photosynthetic capacity (Vcmax25) or leaf nitrogen concentration ([N]) than species at warmer sites. Rdark25 values at any given Vcmax25 or [N] were higher in herbs than in woody plants.
• The results highlight variation in Rdark among species and across global gradients in T and aridity. In addition to their ecological significance, the results provide a framework for improving representation of Rdark in terrestrial biosphere models (TBMs) and associated land-surface components of Earth system models (ESMs)
Colorectal Neuroendocrine Neoplasms: Areas of Unmet Need
The subject of colorectal neuroendocrine neoplasms (NENs), subdivided
into well-differentiated NENs, termed neuroendocrine tumours (NETs;
grade (G) 1 and 2), and poorly differentiated NENs, termed
neuroendocrine carcinomas (NECs; G3) according to the 2010 World Health
Organisation (WHO) classification, has arguably not had as much
attention or study as NENs occurring in other sites. Colorectal NETs and
NECs are however easier to study than many others since they are usually
not difficult to remove and are increasingly detected because of
intensified colorectal cancer screening and surveillance programmes.
Colorectal NETs and NECs show site-specific heterogeneity with variable
behaviour and different therapeutic options; these various aspects
provide unique challenges. Because of bowel cancer screening programmes,
colorectal NENs, like conventional adenocarcinomas, may be diagnosed at
a stage that is associated with improved survival. In this article we
intend to describe and define areas of unmet needs relating to the
epidemiology, classification, pathology, diagnosis and therapy of
colorectal NETs (including NETs G3), colorectal NECs, and finally, mixed
adeno-neuroendocrine carcinomas (MANECs) by reviewing and discussing the
relevant literature
Verona Evidence-Based Meeting (EBM) 2020 on Intraductal Papillary Mucinous Neoplasms (IPMNs) of the Pancreas: Meeting Report
The aim of the Verona EBM 2020 on IPMN project was to increase the level of evidence in the diagnosis and treatment of patients with IPMNs. To this end, worldwide experts from various backgrounds were brought together under the umbrella of an international consortium, to design high-profile multicentric studies addressing open controversies in the field
Global variability in leaf respiration in relation to climate, plant functional types and leaf traits
TRY plant trait database - enhanced coverage and open access
10.1111/gcb.14904GLOBAL CHANGE BIOLOGY261119-18
TRY plant trait database, enhanced coverage and open access
Plant traits-the morphological, ahawnatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives