93 research outputs found
Skillful decadal prediction of German Bight storm activity
We evaluate the prediction skill of the Max Planck Institute Earth System Model (MPI-ESM) decadal hindcast system for German Bight storm activity (GBSA) on a multiannual to decadal scale. We define GBSA every year via the most extreme 3-hourly geostrophic wind speeds, which are derived from mean sea-level pressure (MSLP) data. Our 64-member ensemble of annually initialized hindcast simulations spans the time period 1960–2018. For this period, we compare deterministically and probabilistically predicted winter MSLP anomalies and annual GBSA with a lead time of up to 10 years against observations. The model produces poor deterministic predictions of GBSA and winter MSLP anomalies for individual years but fair predictions for longer averaging periods. A similar but smaller skill difference between short and long averaging periods also emerges for probabilistic predictions of high storm activity. At long averaging periods (longer than 5 years), the model is more skillful than persistence- and climatology-based predictions. For short aggregation periods (4 years and less), probabilistic predictions are more skillful than persistence but insignificantly differ from climatological predictions. We therefore conclude that, for the German Bight, probabilistic decadal predictions (based on a large ensemble) of high storm activity are skillful for averaging periods longer than 5 years. Notably, a differentiation between low, moderate, and high storm activity is necessary to expose this skill
E. coli separatome-based protein expression and purification platform
Provided is a separatome-based peptide, polypeptide, and protein expression and purification platform based on the juxtaposition of the binding properties of host cell genomic peptides, polypeptides, and proteins with the characteristics and location of the corresponding genes on the host cell chromosome of E. coli. The separatome-based protein expression and purification platform quantitatively describes and identifies priority deletions, modifications, or inhibitions of certain gene products to increase chromatographic separation efficiency, defined as an increase in column capacity, column selectivity, or both, with emphasis on the former. Moreover, the separatome-based protein expression and purification platform provides a computerized knowledge tool that, given separatome data, and a target recombinant peptide, polypeptide, or protein, intuitively suggests strategies facilitating efficient product purification. The separatome-based protein expression and purification platform is an efficient bioseparation system that intertwines host cell expression systems and chromatography
A quantum pathway to overcome the trilemma of magnetic data storage
The three essential pillars of magnetic data storage devices are readability,
writeability, and stability. However, these requirements compete as magnetic
domain sizes reach the fundamental limit of single atoms and molecules. The
proven magnetic bistability of individual holmium atoms on magnesium oxide
appeared to operate within this magnetic trilemma, sacrificing writeability for
unprecedented stability. Using the magnetic stray field created by the tip of a
spin-polarized scanning tunneling microscope (SP-STM), we controllably move the
Ho state into the quantum regime, allowing us to write its state via the
quantum tunneling of magnetization (QTM). We find that the hyperfine
interaction causes both the excellent magnetic bistability, even at zero
applied magnetic field, and the avoided level crossings which we use to control
the magnetic state via QTM. We explore how to use such a system to realize a
high-fidelity single atom NOT gate (inverter). Our approach reveals the
prospect of combining the best traits of the classical and quantum worlds for
next generation data storage
Seasonal Prediction of Arabian Sea Marine Heatwaves
Marine heatwaves are known to have a detrimental impact on marine ecosystems, yet predicting when and where they will occur remains a challenge. Here, using a large ensemble of initialized predictions from an Earth System Model, we demonstrate skill in predictions of summer marine heatwaves over large marine ecosystems in the Arabian Sea seven months ahead. Retrospective forecasts of summer (June to August) marine heatwaves initialized in the preceding winter (November) outperform predictions based on observed frequencies. These predictions benefit from initialization during winters of medium to strong El Niño conditions, which have an impact on marine heatwave characteristics in the Arabian Sea. Our probabilistic predictions target spatial characteristics of marine heatwaves that are specifically useful for fisheries management, as we demonstrate using an example of Indian oil sardine (Sardinella longiceps)
Rigidity versus flexibility: is this an issue in S1 (sigma-1) receptor ligand affinity and activity?
A set of stereoisomeric 2,5-diazabicyclo[2.2.2]octanes 14 and 15 was prepared in a chiral-pool synthesis starting from (S)- or (R)-aspartate. The key step in the synthesis was a Dieckmann-analogous cyclization of (dioxopiperazinyl)acetates 8, which involved trapping uf the intermediate hemiketal anion with Me3SiCl. The \u3c31 affinity was tested using membrane preparations from animal (guinea pig) and human origin. The binding of bicyclic compounds was analyzed by molecular dynamics simulations based on a 3D homology model of the \u3c31 receptor. The good correlation between Ki values observed in the \u3c31 assays and calculated free binding energy, coupled with the identification of four crucial ligand/receptor interactions allowed the formulation of structure affinity relationships. In an in vitro antitumor assay with seven human tumor cell lines, the bicyclic compounds inhibited selectively the growth of the cell line A427, which is due to induction of apoptosis. In this assay, the compounds behave like the known \u3c31 receptor antagonist haloperidol
Separatome-based protein expression and purification platform
Provided is a separatome-based recombinant peptide, polypeptide, and protein expression and purification platform based on the juxtaposition of the binding properties of host cell genomic peptides, polypeptides, and proteins with the characteristics and location of the corresponding genes on the host cell chromosome, such as that of E. coli, yeast, Bacillus subtilis or other prokaryotes, insect cells, mammalian cells, etc. This platform quantitatively describes and identifies priority deletions, modifications, or inhibitions of certain gene products to increase chromatographic separation efficiency, defined as an increase in column capacity, column selectivity, or both, with emphasis on the former. Moreover, the platform provides a computerized knowledge tool that, given separatome data and a target recombinant peptide, polypeptide, or protein, intuitively suggests strategies leading to efficient product purification. The separatome-based protein expression and purification platform is an efficient bioseparation system that intertwines host cell expression systems and chromatography
Upgrade of a low-temperature scanning tunneling microscope for electron-spin resonance
Electron spin resonance with a scanning tunneling microscope (ESR-STM) combines the high energy resolution of spin resonance spectroscopy with the atomic scale control and spatial resolution of STM. Here we describe the upgrade of a helium-3 STM with a 2D vector-field magnet (Bz = 8.0 T, Bx = 0.8 T) to an ESR-STM. The system is capable of delivering radio frequency (RF) power to the tunnel junction at frequencies up to 30 GHz. We demonstrate magnetic field-sweep ESR for the model system TiH/MgO/Ag(100) and find a magnetic moment of (1.004 ± 0.001) μB. Our upgrade enables to toggle between a DC mode, where the STM is operated with the regular control electronics, and an ultrafast-pulsed mode that uses an arbitrary waveform generator for pump-probe spectroscopy or reading of spin-states. Both modes allow for simultaneous radiofrequency excitation, which we add via a resistive pick-off tee to the bias voltage path. The RF cabling from room temperature to the 350 mK stage has an average attenuation of 18 dB between 5 and 25 GHz. The cable segment between the 350 mK stage and the STM tip presently attenuates an additional 34+5−3 dB from 10 to 26 GHz and 38+3−2 dB between 20 and 30 GHz. We discuss our transmission losses and indicate ways to reduce this attenuation. We finally demonstrate how to synchronize the arrival times of RF and DC pulses coming from different paths to the STM junction, a prerequisite for future pulsed ESR experiments
Biogeochemical Impacts of a Black Carbon Wet Deposition Event in Halong Bay, Vietnam
Black carbon (BC) is emitted to the atmosphere during biomass, biofuel, and fossil fuel combustion, and leaves the atmosphere via dry or wet deposition on land and on the ocean. On a global scale, wet deposition accounts for about 80% of the total atmospheric BC inputs to the ocean. The input of BC particles to the ocean can enrich surface waters with carbon and associated elements, and owing to high porosity and surface-active properties, BC can alter biogeochemical cycles by sorbing dissolved compounds and promoting aggregation. The rain-mediated input of BC to the ocean and its consequences on nutrient concentrations and particle dynamics were studied in Halong Bay, Vietnam, during a 24-h cycle impacted by short and heavy rainfall events. This study suggests that once introduced in the surface ocean via wet deposition, BC sorbs dissolved organic matter (DOM) and stimulates aggregation processes. The observed wet deposition events were characterized by sudden and pulsed inputs of BC particles that created a thin layer of sinking surface-active aggregates, acting as a net-like scavenger for DOM, nutrients (especially phosphate), and small particles. In addition, the wet deposition events coincided with an enrichment of nutrients in the surface microlayer, with an excess input of nitrogen relative to phosphorus leading to an increase of the molar N:P ratio from 24:1 to 37:1. In the underlying water, the molar N:P ratio also increased (i.e., from 39:1 to 64:1), and this can be attributed to the preferential scavenging of dissolved P-compounds on sinking BC-aggregates
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