bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations and Modeling of Potassium Emission in the Terrestrial Nightglow
Authors: Noll S. , Plane J. M. C. , Feng W. , Proxauf B. , Kimeswenger S. , Kausch W. 
Published: May 2019

AbstractThe ablation of cosmic dust entering the atmosphere causes the formation of an atomic potassium (K) layer in the mesopause region. It can be studied via resonance fluorescence from the K(D1) line at 769.9 nm, stimulated by sunlight or a laser. In addition, the faint emission from a chemiluminescent cycle involving ozone and oxygen atoms has been observed with a nocturnal mean intensity of about 1 Rayleigh. In this study, the K nightglow is investigated in much greater detail, using 2,299 high‐resolution spectra taken with the astronomical echelle spectrograph Ultraviolet and Visual Echelle Spectrograph at Cerro Paranal in Chile (24.6°S) between 2000 and 2014. The seasonal variation is dominated by a maximum in June. During the night, the highest intensities are found close to sunrise. Moreover, there is a clear negative correlation with solar activity. These variations are very different from those of the well‐studied sodium (Na) nightglow. The K nightglow at Cerro Paranal was also simulated with the Whole Atmosphere Community Climate Model including K chemistry. The observed and modeled climatologies do not match well, largely because of unreliable Whole Atmosphere Community Climate Model ozone densities. Satellite‐based profile retrievals for ozone and temperature from Sounding of the Atmosphere using Broadband Emission Radiometry and K from Optical Spectrograph and Infrared Imaging System were then used to simulate the K nightglow and to derive the quantum yield of the K(D) emission with respect to the reaction of K with ozone. Considering that the obscured K(D2) line is expected on theoretical grounds to be 1.67 times brighter than K(D1), we find about 30% for this quantum yield, which is much higher than for Na(D) emission.
Annual Cycle of Planetary Boundary Layer Heights Estimated From Wind Profiler Network Data
Authors: Molod Andrea , Salmun Haydee , Marquardt Collow Allison B. 
Published: May 2019

AbstractThe planetary boundary layer (PBL) height over the U.S. Great and Central Plains during 1992–2012 is examined here using a combination of wind profiler‐derived PBL height estimates and reanalysis fields from the Modern Era Retrospective Reanalysis Version 2. The combined analysis allows for a process level study of the reasons behind the monthly mean behavior of the observed PBL heights under clear‐sky conditions as well as the PBL height variability. Wind profiler PBL height monthly mean annual cycles were grouped into general categories of behavior, each analyzed using Modern Era Retrospective Reanalysis Version 2 fields of sensible and latent heat flux, surface temperature, net radiation, and soil moisture. In the “canonical” category the latent heat plays little role in the determination of the monthly mean PBL height, and it follows the annual cycle of the surface temperature. In the other categories, precipitation and latent heat flux had more influence in setting the annual cycle of the PBL height. An analysis of variance revealed that the role of latent heat in determining the PBL height variations is large (explaining up to 40% of PBL height variability) even in the canonical category for which latent heat played no role in setting the monthly mean. In other categories the latent heat explained up to 80% of the PBL height variations. The amount of that influence is shown to be related to the variability of column soil moisture.
Impact of Solar Radiation Modification on Allowable CO2 Emissions: What Can We Learn From Multimodel Simulations?
Authors: Plazzotta Maxime , Séférian Roland , Douville Hervé 
Published: May 2019

AbstractSolar radiation modification (SRM) is known to strengthen both land and ocean carbon uptake because of its impacts on surface temperature, solar radiation, and other potential drivers of the global carbon cycle. However, the magnitude and timing of the response of both land and ocean carbon uptake to SRM and its consequence on allowable CO2 emissions remain poorly understood. Here we use the results of six Earth system models simulating a continuous stratospheric injection of 5 Tg of sulfur dioxide per year between 2020 and 2069 under the representative concentration pathways 4.5 to investigate the impact of SRM on land and ocean carbon uptake. We find that 50 years of SRM under this protocol increases the allowable CO2 emissions by 40 ± 19 GtC; 85% of this additional uptake of carbon is stored in the land biosphere and 15% in the ocean. This increase in allowable CO2 emissions is however not sustainable after the stoppage of SRM. Earth system models predict a mean release of 8 ± 11 GtC of the carbon back to the atmosphere 20 years after the stoppage which is dominated by large uncertainties in the response of the simulated land carbon cycle to rising temperature and solar radiation. We demonstrate that the time scales of carbon dioxide removal (CDR) potential of SRM are smaller than the time scales of the geological storage assumed in well‐established CDR options. This shows that the CDR potential of SRM should be compared to well‐established CDR options with caution.
Synthesizing Seemingly Contradictory Seismic and Magnetotelluric Observations in the Southeastern United States to Image Physical Properties of the Lithosphere
Authors: Murphy Benjamin S. , Egbert Gary D. 
Published: May 2019

AbstractAlthough seismic velocity and electrical conductivity are both sensitive to temperature, thermal lithosphere properties are derived almost exclusively from seismic data because conductivity is often too strongly affected by minor highly conductive phases to be a reliable indicator of temperature. However, in certain circumstances, electrical observations can provide strong constraints on mantle temperatures. In the southeastern United States (SEUS), magnetotelluric (MT) data require high resistivity values (>300 Ωm) to at least 200‐km depth. As dry mantle mineral conduction laws provide an upper bound on temperature for an observed resistivity value, the only interpretation is that lithospheric temperatures (<1330 °C) persist to 200 km. However, seismic tomography shows that velocities in this region are generally slightly slow with respect to references models; this observation has led to a view of relatively thin (<150 km), eroded thermal lithosphere beneath the SEUS. We show that MT and seismic (tomography, attenuation, receiver function) results are consistent with thick (~200 km), coherent thermal lithosphere in this region. Reduced seismic velocities (relative to reference models) can be explained by considering the effect of finite grain size (anelasticity). Calculated velocity as a function of temperature is overall slower when including anelastic effects, even at reasonable grain sizes of 1 mm to 1 cm; this permits mantle temperatures that are colder than would typically be inferred. We argue for a geodynamic scenario in which the present thermal lithosphere in the SEUS formed in association with the Central Atlantic Magmatic Province and has subsequently survived intact for ~200 Ma.
Continent‐Wide R1/R2 Current System and Ohmic Losses by Broad Dipolarization‐Injection Fronts
Authors: Panov E. V. , Baumjohann W. , Nakamura R. , Weygand J. M. , Giles B. L. , Russell C. T. , Reeves G. , Kubyshkina M. V. 
Published: May 2019

AbstractWe employ Magnetospheric Multiscale, Geostationary Operational Environmental and Los Alamos National Laboratory satellites, as well as the ground magnetometer networks over Greenland and North America to study a substorm on 9 August 2016 between 9 and 10 UT. We found that during the substorm two earthward flows, whose dipolarization‐injection fronts exceeded 6.5 and 4 Earth's radii (RE) in YGSM, impinged and rebounded from Earth's dipolar field lines at L=6–7 downtail, where L is the McIlwain number. The impingements and rebounds ended with a substorm current system of downward R1 and upward R2 currents which grew to azimuthally cover the whole North American continent. At the fronts, regions of enhanced negative j·E′ were formed and peaked toward the end of the impingements. These regions appeared to be conjugate with eastward moving aurora (along the growth phase arc and together with eastward drifting energetic electrons at geosynchronous equatorial orbit), which manifests ionospheric Ohmic losses.
Improving Support to Siblings of Children With Cancer Through a Community-Academic Partnership
Authors: Oberoi Anjali R. , Towry Lisa , Eilenberg Jenna Sandler , Lun Phyllis , Lerro Grace , Alderfer Melissa A. , Long Kristin A. 
Published: May 2019

Objective: Siblings of children with cancer are a psychosocially at-risk group and have unmet needs that are typically not addressed within traditional hospital settings. The current study implemented a community-academic partnership model with SuperSibs—a nationwide, community-based, no-cost program for siblings of children with cancer, powered by Alex’s Lemonade Stand Foundation—to evaluate and improve their sibling resources. Method: Researchers and Alex’s Lemonade Stand Foundation staff partnered to plan and conduct research with siblings regarding desired support resources, with attention to the acceptability and feasibility of implementation. Siblings ( N = 23) provided qualitative data regarding suggestions for new resources and feedback on existing and proposed SuperSibs programs. Qualitative data were analyzed using applied thematic analysis. Results: Siblings emphasize the importance of support that is meaningful, age-appropriate, consistently delivered and that offers autonomy. Siblings recommended revised SuperSibs program initiatives, such as yoga instruction, education for parents and teachers, and game-based interventions. Collaboration throughout the course of the research between researchers and Alex’s Lemonade Stand Foundation staff yielded improvements to SuperSibs programming. Conclusion: Community-academic partnerships are useful in conducting impactful research that is directly translatable into community-based support. Recommendations continue to inform resource development and evaluation goals. Implications for Impact Statement Siblings of children with cancer are a psychosocially at-risk group that receives limited support within traditional hospital settings. This project implemented a community-academic partnership to design and conduct qualitative research aimed at improving community-based sibling support resources from SuperSibs, a free program offered by Alex’s Lemonade Stand Foundation. Findings suggest that the community-academic partnership model has strong potential to improve evidence-based support for siblings.
Structural basis of allosteric regulation of Tel1/ATM kinase
Authors: Xin Jiyu , Xu Zhu , Wang Xuejuan , Tian Yanhua , Zhang Zhihui , Cai Gang 
Published: May 2019

AbstractATM/Tel1 is an apical kinase that orchestrates the multifaceted DNA damage response. Mutations of ATM/Tel1 are associated with ataxia telangiectasia syndrome. Here, we report cryo-EM structures of symmetric dimer (4.1 Å) and asymmetric dimer (4.3 Å) of Saccharomyces cerevisiae Tel1. In the symmetric state, the side chains in Tel1 C-terminus (residues 1129–2787) are discernible and an atomic model is built. The substrate binding groove is completely embedded in the symmetric dimer by the intramolecular PRD and intermolecular LID domains. Point mutations in these domains sensitize the S. cerevisiae cells to DNA damage agents and hinder Tel1 activation due to reduced binding affinity for its activator Xrs2/Nbs1. In the asymmetric state, one monomer becomes more compact in two ways: the kinase N-lobe moves down and the Spiral of α-solenoid moves upwards, which resemble the conformational changes observed in active mTOR. The accessibility of the activation loop correlates with the synergistic conformational disorders in the TRD1-TRD2 linker, FATC and PRD domains, where critical post-translational modifications and activating mutations are coincidently condensed. This study reveals a tunable allosteric network in ATM/Tel1, which is important for substrate recognition, recruitment and efficient phosphorylation.
An essential contractile ring protein controls cell division in Plasmodium falciparum
Authors: Rudlaff Rachel M. , Kraemer Stephan , Streva Vincent A. , Dvorin Jeffrey D. 
Published: May 2019

AbstractDuring the blood stage of human malaria, Plasmodium falciparum parasites divide by schizogony—a process wherein components for several daughter cells are produced within a common cytoplasm and then segmentation, a synchronized cytokinesis, produces individual invasive daughters. The basal complex is hypothesized to be required for segmentation, acting as a contractile ring to establish daughter cell boundaries. Here we identify an essential component of the basal complex which we name PfCINCH. Using three-dimensional reconstructions of parasites at electron microscopy resolution, we show that while parasite organelles form and divide normally, PfCINCH-deficient parasites develop inviable conjoined daughters that contain components for multiple cells. Through biochemical evaluation of the PfCINCH-containing complex, we discover multiple previously undescribed basal complex proteins. Therefore, this work provides genetic evidence that the basal complex is required for precise segmentation and lays the groundwork for a mechanistic understanding of how the parasite contractile ring drives cell division.
Lack of selective resistance of influenza A virus in presence of host-targeted antiviral, UV-4B
Authors: Warfield Kelly L. , Schaaf Kaitlyn R. , DeWald Lisa Evans , Spurgers Kevin B. , Wang Wei , Stavale Eric , Mendenhall Michelle , Shilts Meghan H. , Stockwell Timothy B. , Barnard Dale L. , Ramstedt Urban , Das Suman R. 
Published: May 2019

AbstractDevelopment of antiviral drug resistance is a continuous concern for viruses with high mutation rates such as influenza. The use of antiviral drugs targeting host proteins required for viral replication is less likely to result in the selection of resistant viruses than treating with direct-acting antivirals. The iminosugar UV-4B is a host-targeted glucomimetic that inhibits endoplasmic reticulum α-glucosidase I and II enzymes resulting in improper glycosylation and misfolding of viral glycoproteins. UV-4B has broad-spectrum antiviral activity against diverse viruses including dengue and influenza. To examine the ability of influenza virus to develop resistance against UV-4B, mouse-adapted influenza virus was passaged in mice in the presence or absence of UV-4B and virus isolated from lungs was used to infect the next cohort of mice, for five successive passages. Deep sequencing was performed to identify changes in the viral genome during passaging in the presence or absence of UV-4B. Relatively few minor variants were identified within each virus and the ratio of nonsynonymous to synonymous (dN/dS) substitutions of minor variants confirmed no apparent positive selection following sustained exposure to UV-4B. Three substitutions (one synonymous in PB2, one nonsynonymous in M and PA each) were specifically enriched (>3%) in UV-4B-treated groups at passage five. Recombinant viruses containing each individual or combinations of these nonsynonymous mutations remained sensitive to UV-4B treatment in mice. Overall, these data provide evidence that there is a high genetic barrier to the generation and selection of escape mutants following exposure to host-targeted iminosugar antivirals.
Water transit time and active recharge in the Sahel inferred by bomb-produced 36Cl
Authors: Bouchez Camille , Deschamps Pierre , Goncalves Julio , Hamelin Bruno , Mahamat Nour Abdallah , Vallet-Coulomb Christine , Sylvestre Florence 
Published: May 2019

AbstractThe lack of data and suitable methods to quantify regional hydrological processes often hinders sustainable water management and adaptation to climate change in semiarid regions, particularly in the Sahel, which is known for its climatic variability. Here we show that 36Cl from nuclear tests is a promising method to estimate water transit times and groundwater recharge rates on the catchment scale, and to distinguish water and chloride cycles. 36Cl was measured in 131 surface and groundwater samples in the Chari-Logone sub-catchment of the emblematic Lake Chad Basin, located in central Sahel. It was found that only 12 ± 8% of the catchment is connected to the main rivers. Groundwater supporting rivers in the upper humid part of the catchment has a mean transit time of 9.5 ± 1 years and a recharge rate of 240 ± 170 mm yr−1. In the lower Sahelian part of the catchment, stream-focused recharge yields recharge rates up to 78 ± 7 mm yr−1 in riparian groundwater against 16 ± 27 mm yr−1 elsewhere. Our estimates suggest that aquifers in the Sahel host a significant amount of renewable water, which could therefore be used as a strategic freshwater resource.
Pacing behaviour in laboratory macaques is an unreliable indicator of acute stress
Authors: Poirier Colline , Oliver Caitlin J. , Castellano Bueno Janire , Flecknell Paul , Bateson Melissa 
Published: May 2019

AbstractPacing behaviour, the most frequent stereotypic behaviour displayed by laboratory rhesus macaques (Macaca mulatta) is often used as an indicator of stress. In this study, we investigated how reliable this welfare indicator is at detecting acute stress by testing the reaction of macaques to the stressful event of being exposed to an agonistic interaction between conspecifics housed in the same room but in a different cage. Pacing, agitated locomotion, and stress-related displacement behaviours were quantified before, during and after agonistic interaction exposure, based on video recordings of 13 socially-housed macaques in their home cage. Displacement behaviours increased after agonistic interaction exposure, confirming that the events were experienced as stressful by the focal individuals. The occurrence of pacing did not increase during or after the agonistic interactions. Instead, agitated locomotion increased during the agonistic interactions. These results suggest either, that pacing as an indicator of acute stress is prone to false negative results, increasing in some stressful situations but not others, or that agitated locomotion has been mistaken for pacing in previous studies and that pacing is in fact unrelated to current acute stress. Both interpretations lead to the conclusion that pacing is unreliable as an indicator of acute stress in laboratory rhesus macaques.
Spatially-resolved Brillouin spectroscopy reveals biomechanical abnormalities in mild to advanced keratoconus in vivo
Authors: Shao Peng , Eltony Amira M. , Seiler Theo G. , Tavakol Behrouz , Pineda Roberto , Koller Tobias , Seiler Theo , Yun Seok-Hyun 
Published: May 2019

AbstractMounting evidence connects the biomechanical properties of tissues to the development of eye diseases such as keratoconus, a disease in which the cornea thins and bulges into a conical shape. However, measuring biomechanical changes in vivo with sufficient sensitivity for disease detection has proven challenging. Here, we demonstrate the diagnostic potential of Brillouin light-scattering microscopy, a modality that measures longitudinal mechanical modulus in tissues with high measurement sensitivity and spatial resolution. We have performed a study of 85 human subjects (93 eyes), consisting of 47 healthy volunteers and 38 keratoconus patients at differing stages of disease, ranging from stage I to stage IV. The Brillouin data in vivo reveal increasing biomechanical inhomogeneity in the cornea with keratoconus progression and biomechanical asymmetry between the left and right eyes at the onset of keratoconus. The receiver operating characteristic analysis of the stage-I patient data indicates that mean Brillouin shift of the cone performs better than corneal thickness and maximum curvature respectively. In conjunction with morphological patterns, Brillouin microscopy may add value for diagnosis of keratoconus and potentially for screening subjects at risk of complications prior to laser eye surgeries.
CB2 receptor deletion on myeloid cells enhanced mechanical allodynia in a mouse model of neuropathic pain
Authors: Nent Elisa , Nozaki Chihiro , Schmöle Anne-Caroline , Otte David , Zimmer Andreas 
Published: May 2019

AbstractNeuropathic pain can develop after nerve injury, leading to a chronic condition with spontaneous pain and hyperalgesia. Pain is typically restricted to the side of the injured nerve, but may occasionally spread to the contralateral side, a condition that is often referred to as mirror-image pain. Mechanisms leading to mirror-image pain are not completely understood, but cannabinoid CB2 receptors have been implicated. In this study, we use genetic mouse models to address the question if CB2 receptors on neurons or on microglia/macrophages are involved. First, we show that a GFP reporter protein under control of the CB2 promoter is induced upon partial sciatic nerve ligation in spinal cord, dorsal root ganglia, and highest in sciatic nerve macrophages, but not in neurons. Mice which lack CB2 receptors specifically on myeloid cells (microglia, macrophages) developed a mirror-image allodynia [treatment F1,48 = 45.69, p < 0.0001] similar to constitutive CB2 receptor knockout mice [treatment F1,70 = 92.41, p < 0.0001]. Such a phenotype was not observed after the deletion of CB2 from neurons [treatment F1,70 = 0.1315, p = 0.7180]. This behavioral pain phenotype was accompanied by an increased staining of microglia in the dorsal horn of the spinal cord, as evidenced by an enhanced Iba 1 expression [CB2KO, p = 0.0175; CB2-LysM, p = 0.0425]. Similarly, myeloid-selective knockouts showed an increased expression of the leptin receptor in the injured ipsilateral sciatic nerve, thus further supporting the notion that leptin signaling contributes to the increased neuropathic pain responses of CB2 receptor knockout mice. We conclude that CB2 receptors on microglia and macrophages, but not on neurons, modulate neuropathic pain responses.
Deformities of the Globus Pallidus are Associated with Severity of Suicidal Ideation and Impulsivity in Patients with Major Depressive Disorder
Authors: Kim Kiwon , Shin Jeong-Hyeon , Myung Woojae , Fava Maurizio , Mischoulon David , Papakostas George I. , Choi Kwan Woo , Na Eun Jin , Seo Sang Won , Seong Joon-Kyung , Jeon Hong Jin 
Published: May 2019

AbstractNeuroimaging research increasingly suggests there are biological features related to suicidal risk, including brain morphometric features, leading to an elaborate suicide risk assessment. However, few studies have focused on the severity of suicidal ideation and its association with subcortical anatomy in patients with major depressive disorder (MDD). Here, we mainly investigated whether specific structural differences were present in MDD patients with and without suicidal ideation; and supplemented comparison with and without suicidal attempt. We hypothesized that structures associated with suicidal ideation would be derived from a combination of depression and impulsivity. Local atrophy of subcortical structures in 48 patients with MDD (24 with suicidal ideation and 24 without) and 25 age- and sex-matched healthy controls were compared using a surface-based shape analysis method. There was no difference in brain volume between MDD patients with or without suicidal ideations; or MDD patients with or without suicidal attempt. However, the atrophy level in the left pallidum showed a positive correlation with severity of suicidal risk in MDD patients with suicidal ideation. Local atrophy of the left hippocampus, right caudate, and right pallidum had a positive correlation with total impulsivity. These findings possibly suggest that vulnerability to suicidal attempt can be derived from suicidal ideation combined with depression and impulsivity, related to reduced motivational control.