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MOSAiC was a rare opportunity to obtain observational data on Arctic cyclones (ACs), with at least 22 ACs sampled during four of the five legs. This presentation will illustrate how some of the AC cloud and boundary-layer characteristics produce both thermodynamic and dynamic impacts on the sea ice in the non-melt seasons. Deep clouds associated with the ACs enhanced the downwelling radiation, with the surface radiation dependent on cloud height, temperature, and liquid water layers. Underneath the warm fronts ahead of the ACs, this effect directly warmed the surface, sometimes to the extent of destabilizing the near-surface boundary layer. Synoptically induced low-level jets (LLJs) found within AC warm sectors between the surface warm front and cold front often also provided warm-air advection down to a few hundred meters above the surface, which, in many cases, produced a stable lower boundary layer and enhanced downward sensible heat flux in these AC regions. These effects in some mid-winter ACs produced near-surface temperature increases of 20° C or more compared to the surface temperatures prior to the ACs, with some, but not all, winter cases also producing strong thermal waves penetrating through the snow and ice and reducing sea-ice growth. In some ACs, a quasi-axisymmetric LLJ near the top of the boundary layer in the warm sector and then wrapping around the low center as a “bent-back” feature produces the appearance of two successive LLJs with greatly differing wind directions at the MOSAiC site. The rapid change in wind speed and direction between these LLJ pairs produces a rapid change in the surface stress vector and imparts strong forcing on the sea ice. During MOSAiC, strong ice deformation, lead formation, etc., was observed during the time periods between the two LLJs. Hence, these LLJs not only play a role in the atmospheric thermal impacts on sea ice from ACs, but also on the dynamic impacts.The broad relevance of Arctic Cyclone mesoscale features, such as low-level jets, warm-sector warm-air advection, and cloud macro and microstructure, to the sea-ice thermodynamic and dynamic environment during the MOSAiC field program will be illustrated with MOSAiC case-study observations, including basic meteorological measurements, rawinsondes, ARM remote sensors, surface energy budget measurements, and ice motion measurements.

Sea ice thickness is a key parameter in the polar climate and ecosystem. Thermodynamic and dynamic processes alter the sea ice thickness. The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition provided a unique opportunity to study seasonal sea ice thickness changes of the same sea ice. We analyzed 11 large-scale (∼50 km) airborne electromagnetic sea thickness and surface roughness surveys from October 2019 to September 2020. Data from ice mass balance and position buoys provided additional information. We found that thermodynamic growth and decay dominated the seasonal cycle with a total mean sea ice thickness increase of 1.4 m (October 2019 to June 2020) and decay of 1.2 m (June 2020 to September 2020). Ice dynamics and deformation-related processes, such as thin ice formation in leads and subsequent ridging, broadened the ice thickness distribution and contributed 30% to the increase in mean thickness. These processes caused a 1-month delay between maximum thermodynamic sea ice thickness and maximum mean ice thickness. The airborne EM measurements bridged the scales from local floe-scale measurements to Arctic-wide satellite observations and model grid cells. The spatial differences in mean sea ice thickness between the Central Observatory (

Sea ice drift and deformation shapes the ice cover of the polar oceans, lead opening modulating heat transfer across the ice pack and deformation driven roughness changes affecting momentum transfer from winds and currents. Yet we do not fully understand the seasonal evolution of sea ice deformation. An array of >95 GPS drifting buoys and 11 ice stations was deployed as a Distributed Network around the MOSAiC Central Observatory, capturing scales of sea ice motion between hundreds of meters to up to 200 kilometers. The array drifted across the Arctic in the transpolar drift in less than a year, with an anomalous east-west sea level pressure gradient driving the fast drift. The buoys monitored horizontal deformation of the pack ice from freeze up north of the Laptev Sea to melt in the Greenland Sea. The deformation responds to inertial motion during the freeze up transition to a consolidated ice pack. The fractal dimension of the total deformation changes throughout the year. At smaller scales of about 10 km deformation becomes whiter during the growth season, once the ice pack is consolidated to the coast. There iis an increase in episodic events at the largest scales during the periods the ice pack is consolidated and where it becomes more tidally active during transition through Fram Strait. The MOSAiC distributed network brings improved understanding in the transition of sea ice deformation from freedrift to pack ice, and the response of the ice to changing momentum transfer from the wind and ocean across the Transpolar Drift. The MOSAiC campaign provides unprecedented information about the atmospheric structure and spatial distribution of winds, as well as near surface currents, from which we can deduce the affect of sub-mesoscale deformation in the wind field on the horizontal ice deformation.

Single-molecule techniques provide insights into the heterogeneity and dynamics of ensembles and enable the extraction of mechanistic information that is complementary to high-resolution structural techniques. Here, we describe the application of single-molecule Förster resonance energy transfer to study the dynamics of integral membrane protein complexes on timescales spanning sub-milliseconds to minutes (10

The metal–organic framework (Me2NH2)2[Cd(NO2BDC)2] (SHF-81) comprises flattened tetrahedral Cd(O2CR)42- nodes, in which Cd(II) centres are linked via NO2BDC2- ligands (2-nitrobenzene-1,4-dicarboxylate) to give a doubly interpenetrated anionic network, with charge balanced by two Me2NH2+ cations per Cd centre resident in the pores. The study establishes that this is a twinned α-quartz-type structure (trigonal, space group P3x21, x = 1 or 2), although very close to the higher symmetry β-quartz arrangement (hexagonal, P6x22, x = 2 or 4) in its as-synthesised solvated form [Cd(NO2BDC)2]·2DMF·0.5H2O (SHF-81-DMF). The activated MOF exhibits very little N2 uptake at 77 K, but shows significant CO2 uptake at 273–298 K with an isosteric enthalpy of adsorption (ΔHads) at zero coverage of -27.4 kJ mol-1 determined for the MOF directly activated from SHF-81-DMF. A series of in situ diffraction experiments, both single-crystal X-ray diffraction (SCXRD) and powder X-ray diffraction (PXRD), reveal that the MOF is flexible and exhibits breathing behaviour with observed changes as large as 12% in the a- and b-axes (|Δa|, |Δb| < 1.8 °A) and 5.5% in the c-axis (|Δc| < 0.7 °A). Both the solvated SHF-81-DMF and activated/desolvated SHF-81forms of the MOF exhibit linear negative thermal expansion (NTE), in which pores that run parallel to the c-axis expand in diameter (a- and b-axis) while contracting in length (c-axis) upon increasing temperature. Adsorption of CO2 gas at 298 K also results in linear negative expansion (Δa, Δb > 0; Δc < 0; ΔV > 0). The largest change in dimensions is observed during activation/desolvation from SHF-81-DMF to SHF-81 (Δa, Δb < 0; Δc > 0; ΔV < 0). Collectively the nine in situ diffraction experiments conducted suggest the breathing behaviour is continuous, although individual desolvation and adsorption experiments do not rule out the possibility of a gating or step at intermediate geometries that is coupled with continuous dynamic behaviour towards the extremities of the breathing amplitude.

The metal-organic framework (Me

One way of getting insight into non-Gaussian measures, posed on infinite dimensional Hilbert spaces, is to first obtain best fit Gaussian approximations, which are more amenable to numerical approximation. These Gaussians can then be used to accelerate sampling algorithms. This begs the questions of how one should measure optimality and how the optimizers can be obtained. Here, we consider the problem of minimizing the distance with respect to relative entropy. We examine this minimization problem by seeking roots of the first variation of relative entropy, taken with respect to the mean of the Gaussian, leaving the covariance fixed. Adapting a convergence analysis of Robbins-Monro to the infinite dimensional setting, we can justify the application of this algorithm and highlight necessary assumptions to ensure convergence, not only in the context of relative entropy minimization, but other infinite dimensional problems as well. Numerical examples in path space, showing the robustness of this method with respect to dimension, are provided., corrected typos

Personal samplers used to determine the inhalable fraction of workplace dust are tested while mounted on a manikin, which simulates a worker. To understand the mechanisms affecting the performance of such samplers, researchers must measure the airflow around the body where the samplers are mounted. Therefore, wind tunnel facilities to determine both airflow conditions around samplers and sampling efficiency are needed. A wind tunnel system was developed that was large enough to accommodate the top half of a life-sized manikin and employed a laser Doppler velocimeter for velocity measurements around the manikin. For generating particles up to 70 μm, an aerosol generation system, using a two-dimensional scanning system to cover an extended area, was developed and tested. The generation system had carriages with linear bearings mounted on rod assemblies for scanning in the horizontal and vertical directions. Screw drives, powered by stepper motors under computer control, moved the carriages in a preprogrammed pattern. The generation system was characterized for its ability to generate uniform concentrations of aerosols over an extended area at wind speeds of 0.5 and 2 m/s and particle sizes of 7 and 70 μm. Uniformity of concentration over the area studied, in the absence of the manikin, was 10% relative standard deviation (RSD) or better, except for 7 μm particles at a wind speed of 0.5 m/s where some nonuniformity was observed. The uniformity under these conditions was improved by rearranging the distances between components in the wind tunnel.

Chemical and biological forensic programs rely on laboratory measurements to determine how a threat agent may have been produced. In addition to laboratory analyses, it may also be useful to identify institutions where the same threat agent has been produced by the same (or a similar) process, since the producer of the agent may have learned methods at a university or similar institution. In this paper, we evaluate a Bayesian network that combines the results of laboratory measurements with evidence from scientific literature to probabilistically rank institutions that have published papers on the agent of interest. We apply techniques from multiattribute decision science to assess and compare the performance of various implementations of the Bayesian network in terms of three attributes: fidelity, consumption of the forensic sample, and document curation intensity. The mathematical approach we use to compare the various implementations is generalizable to the evaluation of other signature systems.

Born in Avignon, France on December 10, 1908 as Olivier Eugene Prosper Charles Messiaen and baptized into the Roman Catholic Church on December 25 of the same year, he was one of the most influential composers of the 20th century. Initially self-taught on the piano, Messiaen eventually spent around a decade studying at the Paris Conservatoire under such notable professors as Jean Gallon and Paul Dukas. Upon completing his formal education in music, he accepted the substantial post of organist at the Eglise de la Saint-Trinite in Paris. On June 22, 1932, he married Claire Delbos, the daughter of a notable professor at the Sorbonne, and five years later on July 14, 1937 they had a child whom they named Pascal. Keywords: messiaen, olivier (1908–1992); messiaen, conscripted into french military; famous work, quatuor pour la fin du temps; titles evoking religious stories or images; dialectic, traditional sacred and avant-garde

A low cost ATE-based cache resident test methodology is presented in this paper for testing cores of microprocessor chips with non-deterministic main memory access. No non-determinism (ND) or training sequence handling of the SerDes is needed, simplifying test development, reducing the need for expensive next generation ATE that handle SerDes, and simplifying debug as the SerDes are not tested or used. Even low cost testers (LCT) with low speed interface support initially developed for structural test can be enabled to run these tests.

An extremely dense high-speed serial interface validation tester is presented. By relying on parallelism and on efficient measurement techniques, the proposed tester significantly reduces the time to validate the key parameters for serdes interfaces such as the bit error rate, receiver sensitivity, receiver jitter tolerance, and transmit jitter generation. Key timing specifications include periodic jitter injection with less than 5 psec edge-placement resolution and jitter measurement with 160 fsec sampling delay resolution