Pulsar magnetospheres have strong magnetic fields and large amounts of plasma. The structures of these magnetospheres are studied using force-free electrodynamics. To understand pulsar ...magnetospheres, discussions must include their outer region. However, force-free electrodynamics is limited in it does not handle dissipation. Therefore, a resistive pulsar magnetic field model is needed. To break the ideal magnetohydrodynamic (MHD) condition , Ohm's law is used. This work introduces resistivity depending upon the distance from the star and obtain a self-consistent steady state by time integration. Poloidal current circuits form in the magnetosphere while the toroidal magnetic field region expands beyond the light cylinder and the Poynting flux radiation appears. High electric resistivity causes a large space scale poloidal current circuit and the magnetosphere radiates a larger Poynting flux than the linear increase outside of the light cylinder radius. The formed poloidal-current circuit has width, which grows with the electric conductivity. This result contributes to a more concrete dissipative pulsar magnetosphere model.
Endogenous parathyroid hormone (PTH) and PTH-related peptide (PTHrP) bind to the parathyroid hormone receptor 1 (PTH1R) and activate the stimulatory G-protein (Gs) signaling pathway. Intriguingly, ...the two ligands have distinct signaling and physiological properties: PTH evokes prolonged Gs activation, whereas PTHrP evokes transient Gs activation with reduced bone-resorption effects. The distinct molecular actions are ascribed to the differences in ligand recognition and dissociation kinetics. Here, we report cryoelectron microscopic structures of six forms of the human PTH1R-Gs complex in the presence of PTH or PTHrP at resolutions of 2.8 –4.1 Å. A comparison of the PTH-bound and PTHrP-bound structures reveals distinct ligand-receptor interactions underlying the ligand affinity and selectivity. Furthermore, five distinct PTH-bound structures, combined with computational analyses, provide insights into the unique and complex process of ligand dissociation from the receptor and shed light on the distinct durations of signaling induced by PTH and PTHrP.
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•Cryo-EM structures of PTH-PTH1R-Gs and PTHrP-PTH1R-Gs complex•Structural basis of the affinity and selectivity of PTH1R endogenous ligands•Sequential activation mechanism of the PTH1R by endogenous ligands•Structural changes in the PTH-PTH1R-Gs complex triggered by the ligand dissociation
The six distinct structures of PTH-PTH1R-Gs and PTHrP-PTH1R-Gs reveal the differential endogenous ligand recognition and dynamic conformational change in both the extracellular and intracellular regions. These structures and molecular dynamics simulations provide a ligand dissociation mechanism from the receptor and illuminate the distinct signal durations induced by PTH and PTHrP.
The effects of land-use changes on climate are assessed using specified-concentration simulations complementary to the representative concentration pathway 2.6 (RCP2.6) and RCP8.5 scenarios performed ...for phase 5 of the Coupled Model Intercomparison Project (CMIP5). This analysis focuses on differences in climate and land–atmosphere fluxes between the ensemble averages of simulations with and without land-use changes by the end of the twenty-first century. Even though common land-use scenarios are used, the areas of crops and pastures are specific for each Earth system model (ESM). This is due to different interpretations of land-use classes. The analysis reveals that fossil fuel forcing dominates land-use forcing. In addition, the effects of land-use changes are globally not significant, whereas they are significant for regions with land-use changes exceeding 10%. For these regions, three out of six participating models—the Second Generation Canadian Earth System Model (CanESM2); Hadley Centre Global Environmental Model, version 2 (Earth System) (HadGEM2-ES); and Model for Interdisciplinary Research on Climate, Earth System Model (MIROC-ESM)—reveal statistically significant changes in mean annual surface air temperature. In addition, changes in land surface albedo, available energy, and latent heat fluxes are small but significant for most ESMs in regions affected by land-use changes. These climatic effects are relatively small, as land-use changes in the RCP2.6 and RCP8.5 scenarios are small in magnitude and mainly limited to tropical and subtropical regions. The relative importance of the climatic effects of land-use changes is higher for the RCP2.6 scenario, which considers an expansion of biofuel croplands as a climate mitigation option. The underlying similarity among all models is the loss in global land carbon storage due to land-use changes.
The Global Carbon Budget 2018 (GCB2018) estimated by the atmospheric CO
2 growth rate, fossil fuel emissions, and modeled (bottom‐up) land and ocean fluxes cannot be fully closed, leading to a ...“budget imbalance,” highlighting uncertainties in GCB components. However, no systematic analysis has been performed on which regions or processes contribute to this term. To obtain deeper insight on the sources of uncertainty in global and regional carbon budgets, we analyzed differences in Net Biome Productivity (NBP) for all possible combinations of bottom‐up and top‐down data sets in GCB2018: (i) 16 dynamic global vegetation models (DGVMs), and (ii) 5 atmospheric inversions that match the atmospheric CO
2 growth rate. We find that the global mismatch between the two ensembles matches well the GCB2018 budget imbalance, with Brazil, Southeast Asia, and Oceania as the largest contributors. Differences between DGVMs dominate global mismatches, while at regional scale differences between inversions contribute the most to uncertainty. At both global and regional scales, disagreement on NBP interannual variability between the two approaches explains a large fraction of differences. We attribute this mismatch to distinct responses to El Niño–Southern Oscillation variability between DGVMs and inversions and to uncertainties in land use change emissions, especially in South America and Southeast Asia. We identify key needs to reduce uncertainty in carbon budgets: reducing uncertainty in atmospheric inversions (e.g., through more observations in the tropics) and in land use change fluxes, including more land use processes and evaluating land use transitions (e.g., using high‐resolution remote‐sensing), and, finally, improving tropical hydroecological processes and fire representation within DGVMs.
Key Points
Top‐down and bottom‐up estimates of net land‐atmosphere CO
2 fluxes agree well globally but show important mismatches at regional scales
Regional mismatches are dominated by differences between inversions and interannual variability in CO
2 fluxes
Mismatches between top‐down and bottom‐up data sets are explained by sensitivity to climate and by uncertainty in land use change forcing
An earth system model (MIROC-ESM 2010) is fully described in terms of each model component and their interactions. Results for the CMIP5 (Coupled Model Inter-comparison Project phase 5) historical ...simulation are presented to demonstrate the model's performance from several perspectives: atmosphere, ocean, sea-ice, land-surface, ocean and terrestrial biogeochemistry, and atmospheric chemistry and aerosols. An atmospheric chemistry coupled version of MIROC-ESM (MIROC-ESM-CHEM 2010) reasonably reproduces transient variations in surface air temperatures for the period 1850-2005, as well as the present-day climatology for the zonal-mean zonal winds and temperatures from the surface to the mesosphere. The historical evolution and global distribution of column ozone and the amount of tropospheric aerosols are reasonably simulated in the model based on the Representative Concentration Pathways' (RCP) historical emissions of these precursors. The simulated distributions of the terrestrial and marine biogeochemistry parameters agree with recent observations, which is encouraging to use the model for future global change projections.
Both designed and natural anion-conducting channelrhodopsins (dACRs and nACRs, respectively) have been widely applied in optogenetics (enabling selective inhibition of target-cell activity during ...animal behaviour studies), but each class exhibits performance limitations, underscoring trade-offs in channel structure-function relationships. Therefore, molecular and structural insights into dACRs and nACRs will be critical not only for understanding the fundamental mechanisms of these light-gated anion channels, but also to create next-generation optogenetic tools. Here we report crystal structures of the dACR iC++, along with spectroscopic, electrophysiological and computational analyses that provide unexpected insights into pH dependence, substrate recognition, channel gating and ion selectivity of both dACRs and nACRs. These results enabled us to create an anion-conducting channelrhodopsin integrating the key features of large photocurrent and fast kinetics alongside exclusive anion selectivity.
Krokinobacter eikastus rhodopsin 2 (KR2) is a light-driven Na+ pump found in marine bacterium. KR2 pumps Li+ and Na+, but it becomes an H+ pump in the presence of K+, Rb+, and Cs+. Site-directed ...mutagenesis of the cytoplasmic surface successfully converted KR2 into a light-driven K+ pump, suggesting that ion selectivity is determined at the cytoplasmic surface. Here we extended this research and successfully created a light-driven Cs+ pump. KR2 N61L/G263F pumps Cs+ as well as other monovalent cations in the presence of a protonophore. Ion-transport activities correlated with the additive volume of the residues at 61 and 263. The result suggests that an ion-selectivity filter is affected by these two residues and functions by strict exclusion of K+ and larger cations in the wild type (N61/G263). In contrast, introduction of large residues possibly destroys local structures of the ion-selectivity filter, leading to the permeation of K+ (P61/W263) and Cs+ (L61/F263).
Light-driven outward sodium-pumping rhodopsin (NaR) was recently found in marine bacteria. Krokinobacter eikastus rhodopsin 2 (KR2) actively transports sodium and lithium ions in NaCl and LiCl, ...respectively, while it pumps protons in KCl. NaR has a conserved NDQ (N112, D116, and Q123 in KR2) motif, and previous studies suggested an important role for N112 in the function of KR2. Here we replaced N112 with 19 different amino acids and studied the molecular properties of the mutants. All mutants exhibited absorption bands from a protonated Schiff base in the λmax range from 508 to 531 nm upon heterologous expression in Escherichia coli, whose ion-pumping activity was measured using pH electrodes. The function of these mutants was classified into three phenotypes: wild-type (WT)-like Na+/H+ compatible pump, exclusive H+ pump, and no pump. Among the 19 mutants, only N112D, -G, -S, and -T showed light-driven Na+ pump activity, N112A, -C, -P, -V, -E, -Q, -I, -L, -M, -F, and -W were exclusively H+ pumps, and N112H, -K, -Y, and -R exhibited no pump activity. The mutants of the no pump function lack a blue-shifted M intermediate, indicating that Schiff base deprotonation is a prerequisite for Na+ and H+ pumps. In contrast, the subsequent red-shifted O intermediate was observed for WT and N112V but absent for N112T and N112A, suggesting that observation of this intermediate depends on kinetics. Although N112D, -G, -S, and -T are able to pump Na+, they also pump H+ in NaCl, where Na+ and H+ pumps compete with each other because of the decreased Na+ uptake efficiency. From these facts, an exclusive Na+ pump in NaCl exists only in WT. We conclude that N112 is one of the functional determinants of NaR.
Rhodopsins are one of the most studied photoreceptor protein families, and ion‐translocating rhodopsins, both pumps and channels, have recently attracted broad attention because of the development of ...optogenetics. Recently, a new functional class of ion‐pumping rhodopsins, an outward Na+ pump, was discovered, and following structural and functional studies enable us to compare three functionally different ion‐pumping rhodopsins: outward proton pump, inward Cl− pump, and outward Na+ pump. Here, we review the current knowledge on structure‐function relationships in these three light‐driven pumps, mainly focusing on Na+ pumps. A structural and functional comparison reveals both unique and conserved features of these ion pumps, and enhances our understanding about how the structurally similar microbial rhodopsins acquired such diverse functions. We also discuss some unresolved questions and future perspectives in research of ion‐pumping rhodopsins, including optogenetics application and engineering of novel rhodopsins.
Recent structural and spectroscopic analysis of a new functional class of ion‐pumping rhodopsins, an outward Na+ pump, revealed how structurally similar rhodopsins have acquired novel function. Here, we review the structure‐function relationships among three known ion‐pumping rhodopsins and discuss the future direction of light‐driven ion pump research.
Most of the work examining the relationship between intelligence and job performance has conceptualized intelligence as
. Recent findings, however, have supported the claim that more specific factors ...of intelligence contribute to the prediction of job performance. The present study builds upon prior work on specific cognitive abilities by investigating the relationship between ability tilt, a measure representing differential strength between two specific abilities, and job performance. It was hypothesized that ability tilt would differentially relate to job performance based on whether or not the tilt matched the ability requirements of the job, and that ability tilt would provide incremental validity over
and specific abilities for predicting performance when the tilt matched job requirements. Hypotheses were tested using a large sample from the General Aptitude Test Battery (GATB) database. Ability tilt related with job performance in the expected direction for 27 of the 36 tilt-job combinations examined, with a mean effect size of .04 when the tilt matched job requirements. The mean incremental validities for ability tilt were .007 over
and .003 over
and specific abilities, and, on average, tilt explained 7.1% of the total variance in job performance. The results provide limited evidence that ability tilt may be a useful predictor in addition to ability level, and contribute to our understanding of the role of specific abilities in the workplace.
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