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Recent findings using U-Pb zircon geochronology combined with paleoenvironmental proxies and sedimentological observations have constrained the timing and extent of glacial advances and retreats across southwestern and south-central Gondwana during the Late Paleozoic Ice Age (LPIA). Sedimentary archives deposited during the transition from the latest Carboniferous to the earliest Permian reveal widespread short-term warming as reflected in the loss of subglacial deposits across Gondwana basins, some of which were fully deglaciated by the end of the Carboniferous at 299 Ma. These observations are accompanied by fluctuations in proxies for pCO2 and δ13C across the Carboniferous-Permian transition. These climate oscillations require large scale, short-lived climate forcing mechanisms. One such potential cause may be greenhouse gas emissions related to widespread magmatism across central and northwestern Europe, which has been linked to a deep-seated mantle plume. The effects of igneous activity may be further amplified by the interaction of magma with widely occurring organic-rich sedimentary rocks across this region. The products of this magmatic province predominantly show silicic compositions, but intermediate and basaltic melts also occur in outcrops and cores from the British Isles and southern Sweden (predominantly in the form of dykes and sills), the Oslo and Skagerrak Graben as well as the Northern and Southern Permian Basin, which extends from the North Sea across northern Germany to Poland (predominantly filled with rhyolitic and rhyodacitic volcanics).Available radioisotopic age constraints for these magmatic products are from different isotopic systems whose comparison requires consideration of systematic errors, and often have large uncertainties (at the several million-year level) rendering them unsuitable for studying potential causal relations to contemporaneous climate fluctuations that operate at much shorter timescales. We review these results and present new high-resolution U-Pb zircon CA-TIMS (Chemical Abrasion-Thermal Ionization Mass Spectrometry) ages from volcanic and intrusive products from the Southern Permian Basin and adjacent areas which show that the duration of magmatic activity was much shorter than previously thought. We suggest that greenhouse gas emissions from the magma, and its interaction with biogenic sedimentary rocks, may have been the cause for the observed short-term climate oscillations across the Carboniferous-Permian transition. These short-term events, and their effects, appear to be superimposed on long-term climate drivers such as continental arc volcanism, tropical silicate weathering, as well as changes in the distribution of continents in high latitudes, the opening and closing of oceanic gateways and tectonically induced variation in the equilibrium-line altitude for ice.The research presented here is supported by NSF grant 1728705

A new study has ruled out large, once-molten meteorites called achondrites as sources of Earth’s water.

Researchers used ice core data to reconstruct seasonal temperatures throughout the Holocene. The results link especially hot summers with patterns in Earth’s orbit.

Far from pristine outposts of nature, mountains across the world are being rapidly colonized by non-native plants that spread uphill along roads.

The impact sent surface waves rippling over the Martian surface all the way to NASA’s InSight lander, giving scientists a rare view of the planet’s outer layer.

Radiocarbon dating is a cornerstone of climate and archaeological sciences. But the method is under threat as fossil fuel emissions negate a useful signal from atomic tests.

Tidally locked planets always present the same face to their host stars. What does this mean for their potential to support life?

Since the first exoplanet detection in 1992, the study of exoplanets has received considerable attention. It is becoming apparent that the diversity of the general exoplanet population extends beyond that of the Solar System and includes a variety of structures and compositions. For instance, recent research suggests that if a terrestrial planet forms with substantially more Al and Ca than Earth, it may be entirely rocky and lack a metallic core. Two such planets have been tentatively identified (Dorn et al., 2018). Small-core and coreless planets are expected to differ significantly from Earth. Small cores may have fundamentally different dynamics compared to larger cores, which can affect the heat flow inside the planet and the generation and retention of a magnetic dynamo. Additionally, core size has been shown to affect the development of plate tectonics in numerical models (Osterloo et al. 2021; O'Neill et al., 2017), as well as carbon cycling on a planet. Investigating small-core and coreless planets therefore illustrates the potential diversity of exoplanets and offers insight into different regimes of mantle dynamics and plate tectonics. In this study, we use the code StagYY (Tackley, 2008, 2013) to model the evolution of planets with core mass fractions ranging from 10-1 to 10-6 and compare them to an Earth-like reference model. We use mantle reference viscosities of 1020, 1021, and 1022 Pa·s and crustal yield stresses of 30, 100, and 300 MPa. The planets are set to evolve for 4.5 Gyr. In planets with smaller cores, hot plumes rising from the core-mantle boundary (CMB) are reduced in number and develop slowly compared to large-core planets. In the models with a reference viscosity of 1021 Pa·s and a crustal yield stress of 30 MPa, all planets show subduction and plate tectonic-like behavior. The onset of subduction is delayed in small-core planets compared to the Earth-like reference model. Basalt-enriched material accumulates at the CMB and forms a continuous layer in all planet models; this layer is thicker in small-core planets. Due to insulation by the basalt layer, CMB temperature is significantly higher in small-core planets at the end of the 4.5 Gyr evolution period. For a lower reference viscosity of 1020 Pa·s, subduction is initiated earlier and the basalt layer surrounding the CMB is thicker, while the reverse is true for the higher reference viscosity of 1022 Pa·s. At higher yield stresses, some of the planet models undergo subduction and later transition to a stagnant-lid state. However, for a reference viscosity of 1021 Pa·s and a yield stress of 100 MPa, there is no consistent trend regarding this transition. For a yield stress of 300 MPa, planets with core fractions of 10-3 and larger do not show any subduction, but remain in stagnant-lid state throughout the evolution period. In planets with smaller core fractions, subduction events occur starting at 2.5 Gyr. This agrees with previous research suggesting that a small core size can favor the initiation of plate tectonics (Osterloo et al. 2021; O'Neill et al., 2017). In such cases, core size may crucially influence a planet's habitability, since a large-core planet may lack the plate tectonics that are sometimes considered essential to efficient carbon cycling, while a small-core planet may lack the gravity or magnetic dynamo necessary to sustain life. We conclude that core size influences the onset of subduction and plate tectonics on terrestrial planets, as well as their thermal evolution. Small-core planets tend to initiate subduction later than their large-core counterparts and can also be subject to interior heating due to the hot basalt layers insulating the core. For high crustal yield stresses, small-core planets are more likely to develop plate tectonics, while large-core planets remain in a stagnant-lid state. However, this tendency is not evident at yield stresses below 300 MPa. Figure 1: Interior differentiation of planets with a) Earth-like core size b) core mass fraction of 10-1 c) core mass fraction of 10-6 for a reference viscosity of 1021 Pa·s and crustal yield stress of 100 MPa. References: Dorn, C., Harrison, J. H. D., Bonsor, A. and Hands, T.O. A new class of Super-Earths formed from high-temperature condensates: HD219134 b,55 Cnc e, WASP-47 e, MNRAS, 484 (1), 712–727, doi:10.1093/mnras/sty3435.url:http://dx.doi.org/10.1093/mnras/sty3435, 2018. O'Neill, C., Lowman, J., Wasiliev, J. The effect of galactic chemical evolution on terrestrial exoplanet composition and tectonics, Icarus, 352, 114025, doi: 10.1016/j.icarus.2020.114025, 2020. Oosterloo, M., Höning, D., Kamp, I. E. E., van der Tak, F. F. S. The role of planetary interior in the long-term evolution of atmospheric CO2 on Earth-like exoplanets, A&A, 2021, doi:10.1051/0004-6361/202039664, 2021. Tackley, P. J. Modelling compressible mantle convection with large viscosity contrasts in a three-dimensional spherical shell using the yin-yang grid, Phys. Earth Planet. Inter, 171 (1-4), 7-18, doi: 10.1016/j.pepi.2008.08.005, 2008. Tackley, P. J., Ammann, M., Brodholt, J. P., Dobson, D. P. and Valencia, D. Mantle dynamics in super-Earths: Post-perovskite rheology and self-regulation of viscosity, Icarus 225 (1), 50-61, doi:10.1016/j.icarus.2013.03.013, 2013.

International audience; We have studied in detail the emission spectra of the white phosphor Ba7F12Cl2:Eu2+ as a function of Europium content, excitation wavelength and temperature. The change of the emission spectrum with excitation wavelength shows a systematic shift in the CIE chromaticity diagram from warm white upon excitation in the near UV (370 nm) to cold white upon excitation at shorter wavelengths. The observed intensity changes with europium concentration confirm that energy transfer takes place, which is both concentration and temperature dependent. Temperature and sample dependent lifetime studies show that the observed lifetimes do not change within experimental error between dilute and concentrated Eu-doped samples, and they remain constant between 5 K and room temperature. The second observation confirms the previous results that the thermal quenching of the white emission occurs at high temperature (200 °C). The combination of all observations suggests that the energy transfer takes place first between the normal 4f65 d1 states of the Eu ions located on the 3 different crystallographic sites of Ba, and is followed by subsequent relaxation to anomalous emission states whose emission lifetimes remain constant with sample concentration and temperature from 5 K to 300 K.

Introduction: Tofacitinib is an oral JAK inhibitor indicated for the treatment of rheumatoid arthritis (RA). The efficacy and safety of tofacitinib have been shown in several randomized clinical trials. The study presented here aimed to assess the clinical tolerability and effectiveness of tofacitinib among RA patients in real life. Methods: Consecutive patients between January 2015 and April 2017 with RA who fulfilled the American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) 2010 criteria were included in a prospectively designed analysis of retrospective data. Patients were initiated on tofacitinib 5 mg bid. The primary objective was to analyze the safety of tofacitinib in a real-life cohort. Safety was assessed by the reasons to stop tofacitinib during follow up and changes of liver enzymes, hemoglobin, and creatinine. The secondary outcome was to analyze the frequency of and time to achieve low disease activity (LDA) and remission as defined by 28 joint count disease activity score (DAS28). Results: A total of 144 patients were treated with tofacitinib. A total of 84.9% of patients were pre-exposed to at least one biological agent. The average DAS28 at the initiation of tofacitinib was 4.43. A total of 50.0% of patients were positive for rheumatoid factor and 49.0% for ACPA. The mean follow up was 1.22 years (range 10d&ndash, 3.7a) after initiation of tofacitinib treatment. A total of 94 (64.4%) patients remained on tofacitinib during follow-up. The average time to stop tofacitinib was 190.0 days. Reasons to stop tofacitinib were: insufficient response (n = 23), gastrointestinal symptoms (n = 18), infection (n = 5), myalgia (n = 2), remission (n = 2), headache (n = 2), cough, blue finger syndrome, intolerance, heartburn, psoriasis, and increased liver enzymes (all n = 1). Increased alanine amino transferase (ALAT) or aspartate amino transferase (ASAT) &gt, 2&times, upper limit of normal (ULN) were detected in 3.3% and 4.4% of patients, respectively. Hemoglobin decrease of &gt, 10% was detected in 15.1% of the patients and decreased lymphocytes &lt, 500/&mu, L in 3.4%. An increase of creatinine &gt, 20% was detected in 9.4% of patients. A total of 62.9% and 50.0% of the patients achieved low disease activity (LDA) or remission after a median of 319 and 645 days, respectively. These rates were significantly higher in patients na&iuml, ve to biologic agents as compared to patients pre-exposed to biologics (LDA: na&iuml, ve 100% 92 d, pre-exposed 57.0% 434 d, p &le, 0.001, remission: na&iuml, ve 86.7% 132 d, pre-exposed 44.1%, 692 d, p = 0.001). Conclusions: Tofacitinib is a safe and effective treatment option for patients with RA. Tofacitinib may induce high rates of LDA and remission in patients with active disease, even after the use of one or more biologics, though the rate appeared higher in patients na&iuml, ve to biologics. Tofacitinib may be a valuable option in a treat-to-target approach. Our data demonstrate that Janus kinase (JAK) inhibitors are safe and efficacious in real life patients.

Habituation is a basic process of learning in which repeated exposure to a sensory stimulus leads to a decrease in the strength of neuronal activations and behavioral responses. In addition to increases in neuronal activity, sensory stimuli can also lead to decreases in neuronal activity. Until now, the effects of habituation on stimulus-induced neuronal deactivations have not been investigated. We performed functional magnetic resonance imaging in 30 healthy subjects during repetitive unilat- eral somatosensory stimulation and combined this analysis with a psychophysiological examination of changes in the perception threshold. Consistent with the literature, we found a time-dependent decrease of the positive blood oxygenation level-dependent (BOLD) response (indicative of habitua- tion) in the primary somatosensory cortex (SI) contralateral to the stimulus. In contrast, the negative BOLD response (NBR) in the ipsilateral SI did not show a decrease in amplitude; instead, an increase in amplitude was found, i.e., a stronger NBR (increased response). The increased NBR was associated with an increased perception threshold of the nonstimulated hand. These findings suggest that habitu- ation is not primarily characterized by a decrease in the neuronal response to repeated stimuli but rather a widespread change in the balance between excitatory and inhibitory effects that favors inhibi- tory effects. Hum Brain Mapp 35:152-160, 2014. V C 2012 Wiley Periodicals, Inc.

It is well known that the threshold for somatosensory perception may adapt to different inputs. Recent studies suggest the presence of a modulating effect of somatosensory inputs on the spinal dorsal horn. However, the effects of somatosensory inputs on cerebral processing and, in particular, on the functional and effective connectivity of the somatosensory brain network, are poorly understood. In this study, we investigated the longitudinal impact of somatosensory stimuli on the resting-state functional connectivity and effective connectivity of the somatosensory brain network. We performed resting-state functional magnetic resonance imaging (fMRI) in 12 healthy subjects before and after unilateral electrical median nerve stimulation. We combined this analysis with a psychophysiological examination of changes of the perception threshold. We found that the unilateral median nerve stimulation increased the perception thresholds bilaterally and increased the resting-state functional and effective connectivity between most cortical areas of the somatosensory network. The major finding, however, was a decreased resting-state functional connectivity between both secondary somatosensory cortices and the bilateral medial nuclear complex of the thalamus. This decreased connectivity was correlated with increased perception thresholds. These findings emphasize the importance of the medial thalamic nucleus for the perceptual awareness of somatosensory stimuli. Hum Brain Mapp 34:2343–2352, 2013. © 2012 Wiley Periodicals, Inc.

Understanding possible interactions between blood oxygenation level-dependent (BOLD) responses is critical for model-based analyses and the interpretation of experiments that deal with stimuli presented close together in time. Such interactions are well documented in the case of successive positive BOLD responses. However, the influence that a stimulus-induced, negative BOLD response exerts on a subsequent positive BOLD response has yet to be investigated and is the focus of the current study. We performed functional magnetic resonance imaging on 10 healthy subjects during bilateral electrical median nerve stimulation using five different time intervals between left- and right-sided stimuli. We found an acute interruption of the ongoing negative BOLD response at the onset of the positive BOLD response. Different parameters characterizing the positive BOLD response were estimated. There was no impact of the preceding negative BOLD response on the parameters describing the subsequent positive BOLD response. These findings indicate that the underlying mechanisms for negative and positive BOLD responses do not engage parallel processes. We hypothesize that the negative BOLD response is caused by a decreased release of the same vasodilatative agents that evoke the positive BOLD response. Additionally, our results demonstrate that there is no need to adjust the model of a positive BOLD response due to a preceding negative BOLD response in the same brain area.

Habituation is a basic process of learning in which repeated exposure to a sensory stimulus leads to a decrease in the strength of neuronal activations and behavioral responses. In addition to increases in neuronal activity, sensory stimuli can also lead to decreases in neuronal activity. Until now, the effects of habituation on stimulus‐induced neuronal deactivations have not been investigated. We performed functional magnetic resonance imaging in 30 healthy subjects during repetitive unilateral somatosensory stimulation and combined this analysis with a psychophysiological examination of changes in the perception threshold. Consistent with the literature, we found a time‐dependent decrease of the positive blood oxygenation level‐dependent (BOLD) response (indicative of habituation) in the primary somatosensory cortex (SI) contralateral to the stimulus. In contrast, the negative BOLD response (NBR) in the ipsilateral SI did not show a decrease in amplitude; instead, an increase in amplitude was found, i.e., a stronger NBR (increased response). The increased NBR was associated with an increased perception threshold of the nonstimulated hand. These findings suggest that habituation is not primarily characterized by a decrease in the neuronal response to repeated stimuli but rather a widespread change in the balance between excitatory and inhibitory effects that favors inhibitory effects. Hum Brain Mapp 35:152–160, 2014. © 2012 Wiley‐Periodicals, Inc.

Habituation is a basic process of learning evident in a decrement in neuronal/behavioral responses to repeated sensory stimulation. It is generally accepted that habituation affects all sensory systems in the human brain, including the somatosensory network. However, it is not clear where habituation originates within this hierarchically organized network. In this study, we examined whether habituation effects increase relatively uniformly along the processing hierarchy or rather distinctly at a particular processing stage. We addressed these questions by performing functional magnetic resonance imaging (fMRI) on 43 healthy subjects during unilateral electrical median nerve stimulation using a block design. We found a time-dependent decrease in the positive BOLD response (indicative of habituation) in all areas of the somatosensory network with the exception of Brodmann area (BA) 3b. The increase in habituation within the presumed processing stream was most pronounced between subareas of the primary somatosensory cortex (BA3b, BA1, BA2), and no further increase in habituation effects was observed in the subsequent processing stages within either the secondary somatosensory cortex or the insula. Moreover, we found a relatively strong habituation effect within the thalamus. These findings indicate that the increase in habituation along the processing hierarchy is measurable primarily between subareas of the primary somatosensory cortex, and we hypothesize that this increase originates in thalamocortical interactions early in the processing stream.

Somatosensory signals modulate activity throughout a widespread network in both of the brain hemispheres: the contralateral as well as the ipsilateral side of the brain relative to the stimulated limb. To analyze the ipsilateral somatosensory brain areas that are engaged during limb stimulation, we performed functional magnetic resonance imaging (fMRI) in 12 healthy subjects during electrical median nerve stimulation using both a block‐ and an event‐related fMRI design. Data were analyzed through the use of model‐dependent (SPM) and model‐independent (ICA) approaches. Beyond the well‐known positive blood oxygenation level‐dependent (BOLD) responses, negative deflections of the BOLD response were found consistently in several ipsilateral brain areas, including the primary somatosensory cortex, the supplementary motor area, the insula, the dorsal part of the posterior cingulate cortex, and the contralateral cerebellum. Compared to their positive counterparts, the negative hemodynamic responses showed a different time course, with an onset time delay of 2.4 s and a peak delay of 0.7 s. This characteristic delay was observed in all investigated areas and verified by a second (purely tactile) event‐related paradigm, suggesting a systematic difference for brain areas involved in the processing of somatosensory information. These findings may indicate that the physiological basis of these deactivations differs from that of the positive BOLD responses. Therefore, an altered model for the negative BOLD response may be beneficial to further model‐dependent fMRI analyses. Hum Brain Mapp, 2010. © 2010 Wiley‐Liss, Inc.

The primary somatosensory cortex (SI) has been shown to encode the intensity of a stimulus applied to the contralateral side of the body. Recent studies have demonstrated that ipsilateral SI is also involved in the processing of somatosensory information. In this study, we investigated the dependence of the negative BOLD response in ipsilateral SI on the intensity of somatosensory stimulation. Functional MRI was performed in 12 healthy subjects during electrical median nerve stimulation at four different intensities. A monotonic relationship between stimulus intensity and the strength of the negative BOLD response in ipsilateral SI was found. Additionally, a psychophysiological experiment revealed tight coupling between the stimulus intensity applied to one hand and increased perceptual threshold of the other hand. These findings indicate a stimulus intensity-dependent inhibition of ipsilateral SI.