bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Climate Variability on Snowmelt and Implications for Organic Matter in a High‐Elevation Lake
Authors: Sadro Steven , Sickman James O. , Melack John M. , Skeen Kevin 
Published: June 2018

AbstractFew coupled lake‐watershed studies examine long‐term effects of climate on the ecosystem function of lakes in a hydrological context. We use 32 years of hydrological and biogeochemical data from a high‐elevation site in the Sierra Nevada of California to characterize variation in snowmelt in relation to climate variability and explore the impact on factors affecting phytoplankton biomass. The magnitude of accumulated winter snow, quantified through basinwide estimates of snow water equivalent (SWE), was the most important climate factor controlling variation in the timing and rate of spring snowmelt. Variations in SWE and snowmelt led to significant differences in lake flushing rate, water temperature, and nitrate concentrations across years. On average in dry years, snowmelt started 25 days earlier and proceeded 7 mm/day slower, and the lake began the ice‐free season with nitrate concentrations ~2 μM higher and water temperatures 9°C warmer than in wet years. Flushing rates in wet years were 2.5 times larger than those in dry years. Consequently, particulate organic matter concentrations, a proxy for phytoplankton biomass, were 5–6 μM higher in dry years. There was a temporal trend of increase in particulate organic matter across dry years that corresponded to lake warming independent of variation in SWE. These results suggest that phytoplankton biomass is increasing as a result of both interannual variability in precipitation and long‐term warming trends. Our study underscores the need to account for local‐scale catchment variability that may affect the accumulation of winter snowpack when predicting climate responses in lakes.
Mixing Efficiency in the Presence of Stratification: When Is It Constant?
Authors: Monismith Stephen G. , Koseff Jeffrey R. , White Brian L. 
Published: June 2018

AbstractThe efficiency of the conversion of mechanical to potential energy, often expressed as the flux Richardson number, Rif, is an important determinant of vertical mixing in the ocean. To examine the dependence of Rif on the buoyancy Reynolds number, ReB, we analyze three sets of data: microstructure profiler data for which mixing is inferred from rates of dissipation of turbulent kinetic energy (ε) and temperature variance (χ) measured in the open ocean, time series of spectrally fit values of ε and covariance‐derived buoyancy fluxes measured in nearshore internal waves, and time series of spectrally fit values of ε and χ measured in an energetic estuarine flow. While profiler data are well represented by Rif ≈ 0.2 for 1 < ReB < 1,000, the covariance data have much larger values of ReB and, consistent with direct numerical simulation results, show that Rif ~ ReB−0.5. The estuarine data have values of ReB that fall between those of the other two data sets but also shows Rif ≈ 0.2 for ReB < 5000. Overall, these data suggest that Rif is in general not constant and may be substantially less than 0.2 when ReB is large, although the value at which the transition from constant to ReB‐dependent mixing may depend on additional parameters that are yet to be determined. Nonetheless, for much of the ocean, ReB < 100 and so Rif is constant there.
Small Earthquakes Matter in Injection‐Induced Seismicity
Authors: Brown Megan R. M. , Ge Shemin 
Published: June 2018

AbstractA simplistic triggering mechanism, pore pressure increase from injection, has been the focus of injection‐induced seismicity studies for decades. Research into other possible mechanisms, like poroelastic stress changes, is ongoing, but there has been relatively little focus on earthquake interaction. While studies have looked at how moderate‐magnitude events (M ≥ 3.0) may trigger larger magnitude‐induced seismicity, research into the cumulative effect of the hundreds to thousands of small‐magnitude (M ≤ 3.0) events is lacking. Here we use generic models to compare the possible stress changes from pore pressure increase and from earthquake interactions of small‐magnitude events. We find that the area of increased pore pressure is much larger than that of positive Coulomb static stress transfer; however, maximum Coulomb static stress change is larger than maximum pore pressure increase. We argue that, yes, small earthquakes do matter, and their interaction may be an important triggering mechanism to consider.
Rain on Generative Seas
Authors: Cavaleri Luigi , Bertotti Luciana 
Published: June 2018

AbstractFollowing evidence derived in the field and from previous numerical experiments, we carry out wave modeling tests where the white‐capping and wind input source functions are modified to be functions of also the rain rate and the wind speed. We show the high sensitivity of the results to these parameterizations and how related physically sound, but purely intuitive, choices can reproduce almost perfectly the original results also in extreme conditions. We discuss the related physical and numerical implications.
Increases in Land Surface Temperature in Response to Fire in Siberian Boreal Forests and Their Attribution to Biophysical Processes
Authors: Liu Zhihua , Ballantyne Ashley P. , Cooper L. Annie 
Published: June 2018

AbstractWildfire is the most prevalent natural disturbance in boreal forests and impacts climate through biogeochemical (e.g., greenhouse gas emission from biomass burning) and biophysical (e.g., albedo [α], evapotranspiration [ET], and roughness) processes. We used satellite observations to investigate the immediate (i.e., 1 year after fire) biophysical effects of fire in Siberian boreal forests. We found that boreal forest fires have a net annual warming effect (0.0728 to 0.325 K) due to strong summer warming and weak winter cooling. Fires also increased the diurnal temperature range and seasonal amplitude. These effects are strongest in summer and significantly higher in evergreen than in deciduous coniferous forests. Decreases in ET contributed to warming effects in summer, and increases in α contributed to cooling in winter. Our results suggest that the increase in observed land surface temperature immediately following fires in boreal ecosystems is most likely due to reduced ET leading to a strong positive feedback on the surface radiative budget.
Deep Sea Currents Driven by Breaking Internal Tides on the Continental Slope
Authors: Xie Xiaohui , Liu Qian , Zhao Zhongxiang , Shang Xiaodong , Cai Shuqun , Wang Dongxiao , Chen Dake 
Published: June 2018

AbstractMooring data collected on the continental slope of the South China Sea show that along‐slope deep sea bottom currents are generated when large spring internal tides (internal waves with tidal frequency) are observed, with the maximum velocity amplitude exceeding 0.15 m/s. The observations are consistent with predictions that near‐bottom breaking of internal waves can result in generation of along‐slope flows when these waves obliquely approach the slope. A linear internal tide model in one horizontal dimension with realistic topography and stratification is used to show that the breaking of internal tides is likely due to near‐critical reflection on the slope. Combining the mooring observations and the model simulation, an along‐slope near‐bottom transport of ~0.5 Sv is estimated. Along‐slope bottom flows caused by breaking internal waves potentially provide a significant way to deform continental slopes and affect deep water exchange between the marginal sea and open ocean.
Investigation of Coatings for Langmuir Probes in an Oxygen‐Rich Space Environment
Authors: Samaniego Joseph I. , Wang Xu , Andersson Laila , Malaspina David , Ergun Robert E. , Horányi Mihály 
Published: June 2018

AbstractUse of Langmuir probes in the atmospheres of planets is complicated by oxidation of the probe surface when high‐density oxygen atoms/molecules and/or ions are present. Oxidation of most materials creates an electrically resistive layer on the probe surface that reduces the current collected at a given bias voltage, changing the probe's current‐voltage (I‐V) curves and consequently the measured plasma parameters. TiN (Titanium Nitride), DAG (a graphite coating), or Gold are currently used Langmuir probe coatings, yet they all have issues when exposed to oxygen‐rich environments. Iridium and Rhenium are selected as new coating candidates because of the high conductivity of their oxidized forms and high hardness. Here we present the oxidation effect on the measurements of probes made of current coating materials (DAG, Gold, and TiN) and new coating materials (Iridium and Rhenium) against controls (Copper and Nickel) in the laboratory. The oxidation process is performed by bombarding oxygen ions on the probe surface with energies of 1.5–10 eV. The probe's I‐V curves taken in an argon plasma are compared before and after oxidation. Our results show that the TiN, Gold, and DAG probes show significant to small changes in their I‐V curves, while Iridium outperforms all the other testing materials with almost unchanged I‐V curves after the oxidation process. Additionally, this new coating can be applied for other plasma instruments in which surface oxidation may pose an issue. However, for the application of Iridium to electric field probes, future work must be carried out to determine photoemission characteristics.
Metabolic patterns in insulin-resistant male hypogonadism
Authors: Gevi Federica , Fanelli Giuseppina , Zolla Lello 
Published: June 2018

AbstractMale hypogonadism associated with insulin resistance (IR) very often leads to metabolic syndrome, at variance with hypogonadism in its first stadium of insulin sensitivity (IS). A plasma metabolomic investigation of these patients can provide useful information in comparison with the values of IS patients. To this aim plasma from insulin-resistant males with hypogonadism were analysed by using ultra high-performance liquid chromatography (UHPLC) and high-resolution mass spectrometry (HRMS). Thus, metabolites were compared to the controls through multivariate statistical analysis and grouped by metabolic pathways. Metabolite database searches and pathway analyses identified imbalances in 18–20 metabolic pathways. Glucose metabolism (e.g., glycolysis and the Krebs cycle) is fuelled by amino acids degradation, in particular of branched amino acids, in individuals with lean body mass. Gluconeogenesis is strongly activated. Some crucial pathways such as glycerol are skewed. Mitochondrial electron transport is affected with a reduction in ATP production. Beta-oxidation of short and medium chain fatty acids did not represent an energy source in hypogonadism, at variance with long and branched fatty acids, justifying the increase in fat mass. Carnosine and β-alanine are strongly reduced resulting in increased fatigue and mental confusion. A comparison of IR with IS male hypogonadism will contribute to a better understanding of how these two hormones work in synergy or antagonise each other in humans. It could also help to select patients who will respond to hormone treatment, and provide accurate biomarkers to measure the response to treatment eventually leading to better strategies in preventing systemic complications in patients not fit for hormone replacement therapy.
CREB controls cortical circuit plasticity and functional recovery after stroke
Authors: Caracciolo L. , Marosi M. , Mazzitelli J. , Latifi S. , Sano Y. , Galvan L. , Kawaguchi R. , Holley S. , Levine M. S. , Coppola G. , Portera-Cailliau C. , Silva A. J. , Carmichael S. T. 
Published: June 2018

AbstractTreatments that stimulate neuronal excitability enhance motor performance after stroke. cAMP-response-element binding protein (CREB) is a transcription factor that plays a key role in neuronal excitability. Increasing the levels of CREB with a viral vector in a small pool of motor neurons enhances motor recovery after stroke, while blocking CREB signaling prevents stroke recovery. Silencing CREB-transfected neurons in the peri-infarct region with the hM4Di-DREADD blocks motor recovery. Reversing this inhibition allows recovery to continue, demonstrating that by manipulating the activity of CREB-transfected neurons it is possible to turn off and on stroke recovery. CREB transfection enhances remapping of injured somatosensory and motor circuits, and induces the formation of new connections within these circuits. CREB is a central molecular node in the circuit responses after stroke that lead to recovery from motor deficits.
Analysis of 3800-year-old Yersinia pestis genomes suggests Bronze Age origin for bubonic plague
Authors: Spyrou Maria A. , Tukhbatova Rezeda I. , Wang Chuan-Chao , Valtueña Aida Andrades , Lankapalli Aditya K. , Kondrashin Vitaly V. , Tsybin Victor A. , Khokhlov Aleksandr , Kühnert Denise , Herbig Alexander , Bos Kirsten I. , Krause Johannes 
Published: June 2018

AbstractThe origin ofYersinia pestisand the early stages of its evolution are fundamental subjects of investigation given its high virulence and mortality that resulted from past pandemics. Although the earliest evidence ofY. pestisinfections in humans has been identified in Late Neolithic/Bronze Age Eurasia (LNBA 5000–3500y BP), these strains lack key genetic components required for flea adaptation, thus making their mode of transmission and disease presentation in humans unclear. Here, we reconstruct ancientY. pestisgenomes from individuals associated with the Late Bronze Age period (~3800 BP) in the Samara region of modern-day Russia. We show clear distinctions between our new strains and the LNBA lineage, and suggest that the full ability for flea-mediated transmission causing bubonic plague evolved more than 1000 years earlier than previously suggested. Finally, we propose that severalY. pestislineages were established during the Bronze Age, some of which persist to the present day.
Genetic inactivation of ANGPTL4 improves glucose homeostasis and is associated with reduced risk of diabetes
Authors: Gusarova Viktoria , O’Dushlaine Colm , Teslovich Tanya M. , Benotti Peter N. , Mirshahi Tooraj , Gottesman Omri , Van Hout Cristopher V. , Murray Michael F. , Mahajan Anubha , Nielsen Jonas B. , Fritsche Lars , Wulff Anders Berg , Gudbjartsson Daniel F. , Sjögren Marketa , Emdin Connor A. , Scott Robert A. , Lee Wen-Jane , Small Aeron , Kwee Lydia C. , Dwivedi Om Prakash , Prasad Rashmi B. , Bruse Shannon , Lopez Alexander E. , Penn John , Marcketta Anthony , Leader Joseph B. , Still Christopher D. , Kirchner H. Lester , Mirshahi Uyenlinh L. , Wardeh Amr H. , Hartle Cassandra M. , Habegger Lukas , Fetterolf Samantha N. , Tusie-Luna Teresa , Morris Andrew P. , Holm Hilma , Steinthorsdottir Valgerdur , Sulem Patrick , Thorsteinsdottir Unnur , Rotter Jerome I. , Chuang Lee-Ming , Damrauer Scott , Birtwell David , Brummett Chad M. , Khera Amit V. , Natarajan Pradeep , Orho-Melander Marju , Flannick Jason , Lotta Luca A. , Willer Cristen J. , Holmen Oddgeir L. , Ritchie Marylyn D. , Ledbetter David H. , Murphy Andrew J. , Borecki Ingrid B. , Reid Jeffrey G. , Overton John D. , Hansson Ola , Groop Leif , Shah Svati H. , Kraus William E. , Rader Daniel J. , Chen Yii-Der I. , Hveem Kristian , Wareham Nicholas J. , Kathiresan Sekar , Melander Olle , Stefansson Kari , Nordestgaard Børge G. , Tybjærg-Hansen Anne , Abecasis Goncalo R. , Altshuler David , Florez Jose C. , Boehnke Michael , McCarthy Mark I. , Yancopoulos George D. , Carey David J. , Shuldiner Alan R. , Baras Aris , Dewey Frederick E. , Gromada Jesper 
Published: June 2018

AbstractAngiopoietin-like 4 (ANGPTL4) is an endogenous inhibitor of lipoprotein lipase that modulates lipid levels, coronary atherosclerosis risk, and nutrient partitioning. We hypothesize that loss of ANGPTL4 function might improve glucose homeostasis and decrease risk of type 2 diabetes (T2D). We investigate protein-altering variants in ANGPTL4 among 58,124 participants in the DiscovEHR human genetics study, with follow-up studies in 82,766 T2D cases and 498,761 controls. Carriers of p.E40K, a variant that abolishes ANGPTL4 ability to inhibit lipoprotein lipase, have lower odds of T2D (odds ratio 0.89, 95% confidence interval 0.85–0.92, p = 6.3 × 10−10), lower fasting glucose, and greater insulin sensitivity. Predicted loss-of-function variants are associated with lower odds of T2D among 32,015 cases and 84,006 controls (odds ratio 0.71, 95% confidence interval 0.49–0.99, p = 0.041). Functional studies in Angptl4-deficient mice confirm improved insulin sensitivity and glucose homeostasis. In conclusion, genetic inactivation of ANGPTL4 is associated with improved glucose homeostasis and reduced risk of T2D.
Solvent-controlled growth of inorganic perovskite films in dry environment for efficient and stable solar cells
Authors: Wang Pengyang , Zhang Xingwang , Zhou Yuqin , Jiang Qi , Ye Qiufeng , Chu Zema , Li Xingxing , Yang Xiaolei , Yin Zhigang , You Jingbi 
Published: June 2018

AbstractInorganic halide perovskites such as cesium lead halide are promising due to their excellent thermal stability. Cesium lead iodide (CsPbI3) has a bandgap of 1.73 eV and is very suitable for making efficient tandem solar cells, either with low-bandgap perovskite or silicon. However, the phase instability of CsPbI3 is hindering the further optimization of device performance. Here, we show that high quality and stable α-phase CsPbI3 film is obtained via solvent-controlled growth of the precursor film in a dry environment. A 15.7% power conversion efficiency of CsPbI3 solar cells is achieved, which is the highest efficiency reported for inorganic perovskite solar cells up to now. And more importantly, the devices can tolerate continuous light soaking for more than 500 h without efficiency drop.
Nickel-catalyzed reductive thiolation and selenylation of unactivated alkyl bromides
Authors: Fang Yi , Rogge Torben , Ackermann Lutz , Wang Shun-Yi , Ji Shun-Jun 
Published: June 2018

AbstractChalcogen-containing compounds have received considerable attention because of their manifold applications in agrochemicals, pharmaceuticals, and material science. While many classical methods have been developed for preparing organic sulfides, most of them exploited the transition-metal-catalyzed cross-couplings of aryl halides or pseudo halides with thiols or disulfides, with harsh reaction conditions usually being required. Herein, we present a user-friendly, nickel-catalyzed reductive thiolation of unactivated primary and secondary alkyl bromides with thiosulfonates as reliable thiolation reagents, which are easily prepared and bench-stable. Furthermore, a series of selenides is also prepared in a similar fashion with selenosulfonates as selenolation reagents. This catalytic method offers a facile synthesis of a wide range of unsymmetrical alkyl-aryl or alkyl-alkyl sulfides and selenides under mild conditions with an excellent tolerance of functional groups. Likewise, the use of sensitive and stoichiometric organometallic reagents can be avoided.
A multi-modal MRI study of the central response to inflammation in rheumatoid arthritis
Authors: Schrepf Andrew , Kaplan Chelsea M. , Ichesco Eric , Larkin Tony , Harte Steven E. , Harris Richard E. , Murray Alison D. , Waiter Gordon D. , Clauw Daniel J. , Basu Neil 
Published: June 2018

AbstractIt is unknown how chronic inflammation impacts the brain. Here, we examined whether higher levels of peripheral inflammation were associated with brain connectivity and structure in 54 rheumatoid arthritis patients using functional and structural MRI. We show that higher levels of inflammation are associated with more positive connections between the inferior parietal lobule (IPL), medial prefrontal cortex, and multiple brain networks, as well as reduced IPL grey matter, and that these patterns of connectivity predicted fatigue, pain and cognitive dysfunction. At a second scan 6 months later, some of the same patterns of connectivity were again associated with higher peripheral inflammation. A graph theoretical analysis of whole-brain functional connectivity revealed a pattern of connections spanning 49 regions, including the IPL and medial frontal cortex, that are associated with peripheral inflammation. These regions may play a critical role in transducing peripheral inflammatory signals to the central changes seen in rheumatoid arthritis.
Strong sesquiterpene emissions from Amazonian soils
Authors: Bourtsoukidis E. , Behrendt T. , Yañez-Serrano A. M. , Hellén H. , Diamantopoulos E. , Catão E. , Ashworth K. , Pozzer A. , Quesada C. A. , Martins D. L. , Sá M. , Araujo A. , Brito J. , Artaxo P. , Kesselmeier J. , Lelieveld J. , Williams J. 
Published: June 2018

AbstractThe Amazon rainforest is the world’s largest source of reactive volatile isoprenoids to the atmosphere. It is generally assumed that these emissions are products of photosynthetically driven secondary metabolism and released from the rainforest canopy from where they influence the oxidative capacity of the atmosphere. However, recent measurements indicate that further sources of volatiles are present. Here we show that soil microorganisms are a strong, unaccounted source of highly reactive and previously unreported sesquiterpenes (C15H24; SQT). The emission rate and chemical speciation of soil SQTs were determined as a function of soil moisture, oxygen, and rRNA transcript abundance in the laboratory. Based on these results, a model was developed to predict soil–atmosphere SQT fluxes. It was found SQT emissions from a Terra Firme soil in the dry season were in comparable magnitude to current global model canopy emissions, establishing an important ecological connection between soil microbes and atmospherically relevant SQTs.
Scaling law for excitons in 2D perovskite quantum wells
Authors: Blancon J.-C. , Stier A. V. , Tsai H. , Nie W. , Stoumpos C. C. , Traoré B. , Pedesseau L. , Kepenekian M. , Katsutani F. , Noe G. T. , Kono J. , Tretiak S. , Crooker S. A. , Katan C. , Kanatzidis M. G. , Crochet J. J. , Even J. , Mohite A. D. 
Published: June 2018

AbstractRuddlesden–Popper halide perovskites are 2D solution-processed quantum wells with a general formula A2A’n-1M
n
X3n+1, where optoelectronic properties can be tuned by varying the perovskite layer thickness (n-value), and have recently emerged as efficient semiconductors with technologically relevant stability. However, fundamental questions concerning the nature of optical resonances (excitons or free carriers) and the exciton reduced mass, and their scaling with quantum well thickness, which are critical for designing efficient optoelectronic devices, remain unresolved. Here, using optical spectroscopy and 60-Tesla magneto-absorption supported by modeling, we unambiguously demonstrate that the optical resonances arise from tightly bound excitons with both exciton reduced masses and binding energies decreasing, respectively, from 0.221 m0 to 0.186 m0 and from 470 meV to 125 meV with increasing thickness from n equals 1 to 5. Based on this study we propose a general scaling law to determine the binding energy of excitons in perovskite quantum wells of any layer thickness.