In recent years, global weather forecast models and global climate models have begun to depict intense tropical cyclones, even up to category 5 on the Saffir‐Simpson scale. In light of the limitation ...of horizontal resolution in such models, the author performs calculations, using the extended Best Track data for Atlantic tropical cyclones, to estimate the ability of models with differing grid spacing to represent Atlantic tropical cyclone intensity statistically. Results indicate that, under optimistic assumptions, models with horizontal grid spacing of one fourth degree or coarser should not produce a realistic number of category 4 and 5 storms unless there are errors in spatial attributes of the wind field. Furthermore, the case of Irma (2017) is used to demonstrate the importance of a realistic depiction of angular momentum and to motivate the use of angular momentum in model evaluation.
Key Points
Models with one fourth degree grid spacing or greater should simulate few extreme hurricanes if outer winds are consistent with observations
Comparison of models across a broad range of resolution is inhibited by the use of maximum wind as a primary evaluation metric
The development of immune checkpoint inhibitors has changed the treatment paradigm for advanced cancers across many tumor types. Despite encouraging and sometimes durable responses in a subset of ...patients, most patients do not respond. Tumors have adopted the PD-1/PD-L1 axis for immune escape to facilitate tumor growth, which can be leveraged as a potential target for immune checkpoint inhibitors. On this basis, PD-L1 protein expression on tumor or immune cells emerged as the first potential predictive biomarker for sensitivity to immune checkpoint blockade. The goal of our study was to evaluate PD-L1 as a predictive biomarker based on all US Food and Drug Administration (FDA) drug approvals of immune checkpoint inhibitors. We evaluated the primary studies associated with 45 FDA drug approvals from 2011 until April 2019. In total, there were approvals across 15 tumor types. Across all approvals, PD-L1 was predictive in only 28.9% of cases, and was either not predictive (53.3%) or not tested (17.8%) in the remaining cases. There were 9 FDA approvals linked to a specific PD-L1 threshold and companion diagnostic: bladder cancer (N = 3), non-small cell lung cancer (N = 3), triple-negative breast cancer (N = 1), cervical cancer (N = 1), and gastric/gastroesophageal junction cancer (N = 1) with 8 of 9 (88.9%) with immune checkpoint inhibitor monotherapy. The PD-L1 thresholds were variable both within and across tumor types using several different assays, including approvals at the following PD-L1 thresholds: 1, 5, and 50%. PD-L1 expression was also measured in a variable fashion either on tumor cells, tumor-infiltrating immune cells, or both. In conclusion, our findings indicate that PD-L1 expression as a predictive biomarker has limitations and that the decision to pursue testing must be carefully implemented for clinical decision-making.
A meta-analysis of 62 experimental and 10 non-experimental studies was conducted to evaluate the positive-mood-enhances-creativity generalization. While the results demonstrate that positive mood ...enhances creativity, the strength of that effect is contingent upon the comparative or referent mood state (i.e., neutral or negative mood) as well as the type of creative task. Further, the pattern of effect sizes supports a curvilinear relationship between affective intensity and creative performance. In general, a contextual perspective of mood–creativity relations is supported.
This book presents a comprehensive, contemporary review of tidal environments and deposits. Individual chapters, each written by world-class experts, cover the full spectrum of coastal, ...shallow-marine and even deep-marine settings where tidal action influences or controls sediment movement and deposition. Both siliciclastic and carbonate deposits are covered. Various chapters examine the dynamics of sediment transport by tides, and the morphodynamics of tidal systems. Several chapters explore the occurrence of tidal deposits in the stratigraphic context of entire sedimentary basins. This book is essential reading for both coastal geologists and managers, and geologists interested in extracting hydrocarbons from complex tidal successions.
The upscale aggregation of convection is used to understand the emergence of rotating, coherent midtropospheric structures and the subsequent process of tropical cyclone formation. The Cloud Model, ...version 1 (CM1), is integrated on an f plane with uniform sea surface temperature (SST) and prescribed uniform background flow. Deep convection is maintained by surface fluxes from an ocean with uniform surface temperature. Convection begins to organize simultaneously into moist and dry midtropospheric patches after 10 days. After 20 days, the patches begin to rotate on relatively small scales. Moist cyclonic vortices merge, eventually forming a single dominant vortex that subsequently forms a tropical cyclone on a realistic time scale of about 5 days. Radiation that interacts with clouds and water vapor aids in forming coherent rotating structures. Using the path to genesis provided by the aggregated solution, the relationship between thermodynamic changes within the vortex and changes in the character of convection prior to genesis is explored. Consistent with previous studies, the approach to saturation within the midtropospheric vortex accelerates the genesis process. A novel result is that, prior to genesis, downdrafts become widespread and somewhat stronger. The increased downdraft mass flux leads to stronger and larger surface cold pools. Shear-cold pool dynamics promote the organization of lower-tropospheric updrafts that spin up the surface vortex. It is inferred that the observed inconsistency between convective intensity and thermodynamic stabilization prior to genesis results from sampling limitations of the observations wherein the important cold pool gradients are unresolved.
We consider what can be learnt about the processes of gas accretion and depletion from the kinematic misalignment between the cold/warm gas and stars in local early-type galaxies. Using simple ...analytic arguments and a toy model of the processes involved, we show that the lack of objects with counter-rotating gas reservoirs strongly constrains the relaxation, depletion and accretion time-scales of gas in early-type galaxies. Standard values of the accretion rate, star-formation efficiency and relaxation rate are not simultaneously consistent with the observed distribution of kinematic misalignments. To reproduce that distribution, both fast gas depletion (t
dep ≲ 108 yr; e.g. more efficient star formation) and fast gas destruction (e.g. by active galactic nucleus feedback) can be invoked, but both also require a high rate of gas-rich mergers (>1 Gyr−1). Alternatively, the relaxation of misaligned material could happen over very long time-scales (≃100 dynamical times or ≈1–5 Gyr). We explore the various physical processes that could lead to fast gas depletion and/or slow gas relaxation, and discuss the prospects of using kinematic misalignments to probe gas-rich accretion processes in the era of large integral-field spectroscopic surveys.
The passive removal of toxic heavy metals such as Cd
2+, Cu
2+, Zn
2+, Pb
2+, Cr
3+, and Hg
2+ by inexpensive biomaterials, termed biosorption, requires that the substrate displays high metal uptake ...and selectivity, as well as suitable mechanical properties for applied remediation scenarios. In recent years, many low-cost sorbents have been investigated, but the brown algae have since proven to be the most effective and promising substrates. It is their basic biochemical constitution that is responsible for this enhanced performance among biomaterials. More specifically, it is the properties of cell wall constituents, such as alginate and fucoidan, which are chiefly responsible for heavy metal chelation. In this comprehensive review, the emphasis is on outlining the biochemical properties of the brown algae that set them apart from other algal biosorbents. A detailed description of the macromolecular conformation of the alginate biopolymer is offered in order to explain the heavy metal selectivity displayed by the brown algae. The role of cellular structure, storage polysaccharides, cell wall and extracellular polysaccharides is evaluated in terms of their potential for metal sequestration. Binding mechanisms are discussed, including the key functional groups involved and the ion-exchange process. Quantification of metal–biomass interactions is fundamental to the evaluation of potential implementation strategies, hence sorption isotherms, ion-exchange constants, as well as models used to characterize algal biosorption are reviewed. The sorption behavior (i.e., capacity, affinity) of brown algae with various heavy metals is summarized and their relative performance is evaluated.
This review covers the literature published between January and December in 2018 for marine natural products (MNPs), with 717 citations (706 for the period January to December 2018) referring to ...compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1554 in 469 papers for 2018), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. The proportion of MNPs assigned absolute configuration over the last decade is also surveyed.
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