Scenarios for modeling solar radiation modification.

Making informed future decisions about solar radiation modification (SRM; also known as solar geoengineering)-approaches such as stratospheric aerosol injection (SAI) that would cool the climate by reflecting sunlight-requires projections of the climate response and associated human and ecosystem impacts. These projections, in turn, will rely on simulations with global climate models. As with climate-change projections, these simulations need to adequately span a range of possible futures, describing different choices, such as start date and temperature target, as well as risks, such as termination or interruptions. SRM modeling simulations to date typically consider only a single scenario, often with some unrealistic or arbitrarily chosen elements (such as starting deployment in 2020), and have often been chosen based on scientific rather than policy-relevant considerations (e.g., choosing quite substantial cooling specifically to achieve a bigger response). This limits the ability to compare risks both between SRM and non-SRM scenarios and between different SRM scenarios. To address this gap, we begin by outlining some general considerations on scenario design for SRM. We then describe a specific set of scenarios to capture a range of possible policy choices and uncertainties and present corresponding SAI simulations intended for broad community use.

Limited surface impacts of the January 2021 sudden stratospheric warming.

Subseasonal weather prediction can reduce economic disruption and loss of life, especially during "windows of opportunity" when noteworthy events in the Earth system are followed by characteristic weather patterns. Sudden stratospheric warmings (SSWs), breakdowns of the winter stratospheric polar vortex, are one such event. They often precede warm temperatures in Northern Canada and cold, stormy weather throughout Europe and the United States - including the most recent SSW on January 5th, 2021. Here we assess the drivers of surface weather in the weeks following the SSW through initial condition "scrambling" experiments using the real-time CESM2(WACCM6) Earth system prediction framework. We find that the SSW itself had a limited impact, and that stratospheric polar vortex stretching and wave reflection had no discernible contribution to the record cold in North America in February. Instead, the tropospheric circulation and bidirectional coupling between the troposphere and stratosphere were dominant contributors to variability.

Interfacial properties of the nanostructured dye-sensitized solid heterojunction TiO(2)/RuL(2)(NCS)(2)/CuI.

The interfaces of the nanostructured dye-sensitized solid heterojunction TiO(2)/Ru-dye/CuI have been studied using photoelectron spectroscopy of core and valence levels, x-ray absorption spectroscopy and atomic force microscopy. A nanostructured anatase TiO(2) film sensitized with RuL(2)(NCS)(2) [cis-bis(4,4(')-dicarboxy-2,2(')-bipyridine)-bis(isothio-cyanato)-ruthenium(II)] was prepared in a controlled way using a novel combined in-situ and ex-situ (Ar atmosphere) method. Onto this film CuI was deposited in-situ. The formation of the dye-CuI interface and the changes brought upon the dye-TiO(2) interface could be monitored in a stepwise fashion. A direct interaction between the dye NCS groups and the CuI is evident in the core level photoelectron spectra. Concerning the energy matching of the valence electronic levels, the photoelectron spectra indicate that the dye HOMO overlaps in energy with the Cu 3d-I 5p hydrid states. The CuI grow in the form of particles, which at the initial stages displace the dye molecules causing dye-TiO(2) bond breaking. Consequently, the very efficient charge injection channel provided by the dye-TiO(2) carboxylic bonding is directly affected for a substantial part of the dye molecules. This may be of importance for the functional properties of such a heterojunction.

Inter- and intra-molecular migration of peptide amide hydrogens during electrospray ionization.

The isotopic exchange of amide hydrogens in proteins in solution strongly depends on the surrounding protein structure, thereby allowing structural studies of proteins by mass spectrometry. However, during electrospray ionization (ESI), gas phase processes may scramble or deplete the isotopic information. These processes have been investigated by on-line monitoring of the exchange of labile deuterium atoms in homopeptides with hydrogens from a solvent suitable for ESI. The relative contribution of intra- and inter-molecular exchange in the gas phase could be studied from their distinct influence on the well-characterized exchange processes in the spraying solution. The deuterium content of individual labile hydrogens was assessed from the isotopic patterns of two consecutive collision-induced dissociation fragments, as observed with a 9.4 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. Results demonstrate that gas phase exchange in the high-pressure region between the capillary and the skimmer cause substantial depletion of the isotopic information of penta-phenylalanine and penta-aspartic acid. For penta-alanine and hexa-tyrosine, the amide hydrogens located close to the N-terminus are depleted from deuterium during mass analysis. Amide hydrogens located close to the C-terminus still retain the information of the isotopic state in solution, but they are redistributed by intra-molecular exchange of the amide hydrogens with the C-terminal hydroxyl group.

Extraction of quantitative blur measures for circumscribed lesions in mammograms.

This study investigates ways of improving lesion diagnosis in mammograms by deriving quantitative descriptions of the lesion periphery. The descriptions are derived by computer image analysis methods. The degree of blur at lesion boundaries is of prime concern, as poorly outlined lesions can indicate malignancy. The need for quantitative analysis arises from psychological evidence suggesting that the human visual system cannot precisely estimate the degree of blur. To help find suitable measures a set of 'artificial' lesions has been generated by convolving a step-like edge with a set of Gaussian functions G(sigma) where sigma characterizes the degree of blur. From these generated lesion images the parameters sigma are derived by the process involving deconvolution. As the edge changes are most important in radial directions, the measures of sigma are calculated for each radial profile of the lesion. The derived individual values correspond very closely to those used to generate the lesions. Statistical measures obtained from them allow distinction between edges which are blurred to different extents and yet are impossible to differentiate visually. The artificial lesions will be combined with mammographic data, and similar measures derived. The work will be validated on real lesions for which the histological findings are known from performed biopsies.

[An atypical case of Aujeszky's disease in a dog (author's transl)]. / Een atypische vorm van de ziekta van Aujerzky bij een hand

Two cases of Aujeszky's disease in a cat and a dog belonging to the same owner are reported. The two animals each were five months of age. The symptoms shown by the cat were typical of Aujeszky's disease: intense itching, salivation and the head bent to one side. The main symptoms shown by the dog consisted in salivation, ptosis of one eye, a drooping ear, the head bent to one side and ataxia. As itching was not observed in the dog and the animal had spent the first months of its life in wooded surroundings, it could also have been affected with rabies, although it had been inoculated with LEP-Flury vaccine forty days prior to importation. It is of importance to the practitioner to know that itching may be absent in dogs with Aujeszky's disease and that rabies should also be suspected in these cases. Only a laboratory diagnosis will be conclusive. Studies were negative for rabies, the virus of Aujeszky's disease being found to be present in the two cases. The source of infection probably consisted in contaminated pork offal (larynges).

Remote radar sensing: atmospheric structure and insects.

A high-resolution radar sounder has been used in the simultaneous detection of atmospheric structure and insects. The vertical distribution of insects was often correlated with atmospheric structure. Continuous recordings revealed diurnal fluctuations and layering of insects at various altitudes.