bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of global warming on the rise of volcanic plumes and implications for future volcanic aerosol forcing
Authors: Aubry Thomas J. , Jellinek A. Mark , Degruyter Wim , Bonadonna Costanza , Radić Valentina , Clyne Margot , Quainoo Adjoa 
Published: November 2016

AbstractVolcanic eruptions have a significant impact on climate when they inject sulfur gases into the stratosphere. The dynamics of eruption plumes is also affected by climate itself, as atmospheric stratification impacts plumes' height. We use an integral plume model to assess changes in volcanic plume maximum rise heights as a consequence of global warming, with atmospheric conditions from an ensemble of global climate models, using three representative concentration pathways (RCP) scenarios. Predicted changes in atmospheric temperature profiles decrease the heights of tropospheric and lowermost stratospheric volcanic plumes and increase the tropopause height, for the RCP4.5 and RCP8.5 scenarios in the coming three centuries. Consequently, the critical mass eruption rate required to cross the tropopause increases by up to a factor of 3 for tropical regions and up to 2 for high‐latitude regions. A number of recent lower stratospheric plumes, mostly in the tropics (e.g., Merapi, 2010), would be expected to not cross the tropopause starting from the late 21st century, under RCP4.5 and RCP8.5 scenarios. This effect could result in a ≃5–25% decrease in the average SO2 flux into the stratosphere carried by small plumes, the frequency of which is larger than the rate of decay of volcanic stratospheric aerosol, and a ≃2–12% decrease of the total flux. Our results suggest the existence of a positive feedback between climate and volcanic aerosol forcing. Such feedback may have minor implications for global warming rate but can prove to be important to understand the long‐term evolution of volcanic atmospheric inputs.
Quantifying and reducing uncertainties in estimated soil CO2fluxes with hierarchical data‐model integration
Authors: Ogle Kiona , Ryan Edmund , Dijkstra Feike A. , Pendall Elise 
Published: November 2016

AbstractNonsteady state chambers are often employed to measure soil CO2fluxes. CO2concentrations (C) in the headspace are sampled at different times (t), and fluxes (f) are calculated from regressions ofCversustbased on a limited number of observations. Variability in the data can lead to poor fits and unreliablefestimates; groups with too few observations or poor fits are often discarded, resulting in “missing”fvalues. We solve these problems by fitting linear (steady state) and nonlinear (nonsteady state, diffusion based) models ofCversust, within a hierarchical Bayesian framework. Data are from the Prairie Heating and CO2Enrichment study that manipulated atmospheric CO2, temperature, soil moisture, and vegetation. CO2was collected from static chambers biweekly during five growing seasons, resulting in >12,000 samples and >3100 groups and associated fluxes. We comparefestimates based on nonhierarchical and hierarchical Bayesian (B versus HB) versions of the linear and diffusion‐based (L versus D) models, resulting in four different models (BL, BD, HBL, and HBD). Three models fit the data exceptionally well (R2 ≥ 0.98), but the BD model was inferior (R2 = 0.87). The nonhierarchical models (BL and BD) produced highly uncertainfestimates (wide 95% credible intervals), whereas the hierarchical models (HBL and HBD) produced very precise estimates. Of the hierarchical versions, the linear model (HBL) underestimatedfby ~33% relative to the nonsteady state model (HBD). The hierarchical models offer improvements upon traditional nonhierarchical approaches to estimatingf, and we provide example code for the models.
Sediment carbon sink in low‐density temperate eelgrass meadows (Baltic Sea)
Authors: Jankowska Emilia , Michel Loïc N. , Zaborska Agata , Włodarska‐Kowalczuk Maria 
Published: November 2016

AbstractSeagrass meadows are highly productive habitats that can act as “blue carbon sinks” in coastal ecosystems by facilitating sedimentation and trapping particles. However, the magnitude and occurrence of these effects may be species and density dependent. The present study is the first estimation of seagrass sediment carbon sink in the temperate Zostera marina beds in the Baltic Sea. Several descriptors of organic matter characteristics, along with possible organic matter sources in the sediment were compared at vegetated and unvegetated bottoms. The 210Pb dating of the sediment has been used for accumulation rate assessment. The photopigments and POC concentrations in sediments were higher in vegetated bottoms. The SIAR (Stable Isotopes in R) mixing model based on nitrogen and carbon stable isotope values, indicated that higher percentages of organic matter originated from seagrass production in vegetated sediments (40–45%) compared to unvegetated ones (5–21%). The carbon stock in the upper 10 cm of the vegetated sediments ranged from 50.2 ± 2.2 to 228.0 ± 11.6 (g m−2), whereas the annual C accumulation amount from 0.84 ± 0.2 to 3.85 ± 1.2 (g m−2 yr−1). Our study shows that even the relatively weakly developed vegetation of the small temperate seagrass species enhance organic carbon concentration in the sediments. Estimated carbon stock was much lower than those reported for most of the seagrass meadows elsewhere, and the carbon burial rate was the lowest ever reported. Evidently, the global calculations of sediment carbon stock should be reconsidered by taking into account density and species‐related variability.
Snowpack fluxes of methane and carbon dioxide from high Arctic tundra
Authors: Pirk Norbert , Tamstorf Mikkel P. , Lund Magnus , Mastepanov Mikhail , Pedersen Stine H. , Mylius Maria R. , Parmentier Frans‐Jan W. , Christiansen Hanne H. , Christensen Torben R. 
Published: November 2016

AbstractMeasurements of the land‐atmosphere exchange of the greenhouse gases methane (CH4) and carbon dioxide (CO2) in high Arctic tundra ecosystems are particularly difficult in the cold season, resulting in large uncertainty on flux magnitudes and their controlling factors during this long, frozen period. We conducted snowpack measurements of these gases at permafrost‐underlain wetland sites in Zackenberg Valley (NE Greenland, 74°N) and Adventdalen Valley (Svalbard, 78°N), both of which also feature automatic closed chamber flux measurements during the snow‐free period. At Zackenberg, cold season emissions were 1 to 2 orders of magnitude lower than growing season fluxes. Perennially, CH4 fluxes resembled the same spatial pattern, which was largely attributed to differences in soil wetness controlling substrate accumulation and microbial activity. We found no significant gas sinks or sources inside the snowpack but detected a pulse in the δ13C‐CH4 stable isotopic signature of the soil's CH4 source during snowmelt, which suggests the release of a CH4 reservoir that was strongly affected by methanotrophic microorganisms. In the polygonal tundra of Adventdalen, the snowpack featured several ice layers, which suppressed the expected gas emissions to the atmosphere, and conversely lead to snowpack gas accumulations of up to 86 ppm CH4 and 3800 ppm CO2 by late winter. CH4 to CO2 ratios indicated distinctly different source characteristics in the rampart of ice‐wedge polygons compared to elsewhere on the measured transect, possibly due to geomorphological soil cracks. Collectively, these findings suggest important ties between growing season and cold season greenhouse gas emissions from high Arctic tundra.
Growth dynamics of black spruce (Picea mariana) in a rapidly thawing discontinuous permafrost peatland
Authors: Sniderhan Anastasia E. , Baltzer Jennifer L. 
Published: November 2016

AbstractHigh‐latitude warming has led to radical changes in abiotic conditions influencing forest growth. In the North American boreal forest, widespread declines in forest productivity (particularly in western regions) and changing climate‐growth relationships have been documented. Previous studies have proposed that this decline can be attributed to drought stress as increasing temperatures may cause evapotranspirative demand to exceed available moisture. We used tree ring studies to document growth dynamics of black spruce, one of the most dominant boreal tree species, in a boreal peatland experiencing rapid permafrost thaw. We specifically look at how changing permafrost conditions influence growth. Growth of black spruce at this site has declined steadily since the mid‐1900s and exhibited a shift from positive responses to temperature pre‐1970 to predominantly negative responses in recent decades, despite precipitation increasing over time at this site. Our results show that there is no apparent effect of landscape position or rate of lateral permafrost thaw on growth trends of black spruce, despite gradients in soil moisture and active layer thickness across the mosaic of wetlands and drier permafrost plateaus at this site. However, this does not imply no effect of permafrost thaw on growth; our results support growing evidence that vertical permafrost thaw (i.e., active layer thickening) is causing drought stress in these slow‐growing, shallow‐rooted trees. To our knowledge, this study is the first to investigate permafrost as a driver of within‐site variability in growth‐climate responses, and we provide insight into the widespread growth declines and divergence of climate‐growth relationships in high‐latitude forests.
Soil N transformations and its controlling factors in temperate grasslands in China: A study from 15N tracing experiment to literature synthesis
Authors: Wang Jing , Wang Liang , Feng Xiaojuan , Hu Huifeng , Cai Zucong , Müller Christoph , Zhang Jinbo 
Published: November 2016

AbstractTemperate grasslands in arid and semiarid regions cover about 40% of the total land area in China. So far, only a few studies have studied the N transformations in these important ecosystems. In the present study, soil gross N transformation rates in Inner Mongolia temperate grasslands in China were determined using a 15N tracing experiment and combined with a literature synthesis to identify the soil N transformation characteristics and their controlling factors in a global perspective. Our results showed that the rates of gross N mineralization and immobilization NH4+ were significantly lower, while autotrophic nitrification rates were significantly higher in Chinese temperate grassland soils compared to other regions in the world. In particular, the primary mineral N consumption processes, i.e., immobilization of NO3− and NH4+, and dissimilatory nitrate reduction to ammonium, were on average much lower in temperate grassland soils in China, compared to other temperate grassland regions. The reduced heterotrophic activity and microbial growth associated with lower soil organic carbon and arid climate (e.g., mean annual precipitation) were identified as the main factors regulating soil N cycling in the studied regions in China. To restrict NO3− accumulation and associated high risks of N losses in these arid and semiarid ecosystems in China, it is important to develop the regimes of soil organic C and water management that promote the retention of N in these grassland ecosystems.
Low contribution of internal metabolism to carbon dioxide emissions along lotic and lentic environments of a Mediterranean fluvial network
Authors: Gómez‐Gener Lluís , von Schiller Daniel , Marcé Rafael , Arroita Maite , Casas‐Ruiz Joan Pere , Staehr Peter Anton , Acuña Vicenç , Sabater Sergi , Obrador Biel 
Published: November 2016

AbstractInland waters are significant sources of carbon dioxide (CO2) to the atmosphere. CO2 supersaturation and subsequent CO2 emissions from inland waters can be driven by internal metabolism, external inputs of dissolved inorganic carbon (DIC) derived from the catchment, and other processes (e.g., internal geochemical reactions of calcite precipitation or photochemical mineralization of organic solutes). However, the sensitivity of the magnitude and sources of CO2 emissions to fluvial network hydromorphological alterations is still poorly understood. Here we investigated both the magnitude and sources of CO2 emissions from lotic (i.e., running waters) and lentic (i.e., stagnant waters associated to small dams) waterbodies of a Mediterranean fluvial network by computing segment‐scale mass balances of CO2. Our results showed that sources other than internal metabolism sustained most (82%) of the CO2 emissions from the studied fluvial network. The magnitude and sources of CO2 emissions in lotic waterbodies were highly dependent on hydrology, with higher emissions dominated by DIC inputs derived from the catchment during high flows and lower emissions partially fueled by CO2 produced biologically within the river during low flows. In contrast, CO2 emissions in lentic waterbodies were low, relatively stable over the time and the space, and dominated by DIC inputs from the catchment regardless of the different hydrological situations. Overall, our results stress the sensitivity of fluvial networks to human activities and climate change and particularly highlight the role of hydromorphological conditions on modulating the magnitude and sources of CO2 emissions from fluvial networks.
Coupling between lower‐tropospheric convective mixing and low‐level clouds: Physical mechanisms and dependence on convection scheme
Authors: Vial Jessica , Bony Sandrine , Dufresne Jean‐Louis , Roehrig Romain 
Published: November 2016

AbstractSeveral studies have pointed out the dependence of low‐cloud feedbacks on the strength of the lower‐tropospheric convective mixing. By analyzing a series of single‐column model experiments run by a climate model using two different convective parametrizations, this study elucidates the physical mechanisms through which marine boundary‐layer clouds depend on this mixing in the present‐day climate and under surface warming. An increased lower‐tropospheric convective mixing leads to a reduction of low‐cloud fraction. However, the rate of decrease strongly depends on how the surface latent heat flux couples to the convective mixing and to boundary‐layer cloud radiative effects: (i) on the one hand, the latent heat flux is enhanced by the lower‐tropospheric drying induced by the convective mixing, which damps the reduction of the low‐cloud fraction, (ii) on the other hand, the latent heat flux is reduced as the lower troposphere stabilizes under the effect of reduced low‐cloud radiative cooling, which enhances the reduction of the low‐cloud fraction. The relative importance of these two different processes depends on the closure of the convective parameterization. The convective scheme that favors the coupling between latent heat flux and low‐cloud radiative cooling exhibits a stronger sensitivity of low‐clouds to convective mixing in the present‐day climate, and a stronger low‐cloud feedback in response to surface warming. In this model, the low‐cloud feedback is stronger when the present‐day convective mixing is weaker and when present‐day clouds are shallower and more radiatively active. The implications of these insights for constraining the strength of low‐cloud feedbacks observationally is discussed.
Chromosomal Numerical Aberrations
Authors: Storchova Zuzana 
Published: November 2016

Abstract

Numerical aberrations (whole chromosomal aneuploidy) represent a significant proportion of chromosomal changes found in humans. These aberrations can occur as a consequence of chromosome segregation defects during cell division. Segregation errors that arise during reductive cell division, or meiosis, are upon fertilisation and subsequent embryo development constitutively present in all cells, resulting in whole organismal aneuploidy. Missegregation in mitosis leads to a mosaic distribution of aneuploidy in somatic cells. Aneuploidy is associated with pathological states in most organisms. Numerical aberrations represent a significant cause of pregnancy loss as well as abnormalities found in live births. Moreover, numerical aberrations are frequently found in ageing tissues or in tumour cells. Although the association of aneuploidy and cancer is known for almost a century, the dispute whether this is a cause or a consequence of cell transformation is still ongoing. Recently, new evidence is emerging that numerical aberrations significantly alter the physiology of eukaryotic cells and might indeed directly contribute to tumourigenesis.

Key Concepts

Numerical chromosomal aberrations result from errors in chromosome segregations.

Trisomy, monosomy and polyploidy are among the major causes of spontaneous human abortions.

Trisomies compatible with survival often result in multiple defects.

Numerical chromosomal aberrations significantly alter physiology of eukaryotic cells.

Numerical chromosomal aberrations are frequently found in cancer cells and can contribute to tumourigenesis.
Direct Labelling of Proteins with
125
I
Authors: Gjøen Tor , Berg Trond 
Published: November 2016

Abstract

To quantify binding to receptors and endocytosis of protein ligands, radioactive labelling with
125
I is still the most widely used technique. It combines high sensitivity with simple analysis and is the method of choice for most applications. Radioactive iodine can be directly coupled to tyrosine residues or via adducts that accumulate in the cells at their site of degradation. Two different methods for rapid direct labelling of proteins can be used for studying
in vivo
metabolism (blood clearance and degradation) or receptor kinetics and cellular uptake and degradation.

Key Concepts

Tracing labelled proteins
in vitro
and
in vitro
.

Protein binding to receptors.

Endocytosis and subcellular trafficking of proteins.

Lysosomal degradation.

Radioactive tracers.
Autophagy in Nonmammalian Systems
Authors: Mastrodonato Valeria , Morelli Elena , Vaccari Thomas 
Published: November 2016

Abstract

Autophagy, or ‘self‐eating’, is a catabolic process that enables lysosome‐mediated degradation of cytoplasmic contents and recycling of macromolecules to be used in essential cellular processes. This process enables cells to survive during nutrient restriction, participates in cell death during development and functions in clearance of protein aggregates and intracellular pathogens. Autophagy has been widely studied in yeast,
Drosophila
and
Caenorhabditis elegans
, and studies in these organisms have revealed regulation by multiple cellular pathways. These include cell growth regulators, such as the Class I PI3 kinase and target of rapamycin (Tor), as well as cell death regulators, including caspases. Defects in autophagy are associated with neurodegeneration, pathogen infection, cancer and reduced lifespan. Genetic experiments in model organisms have been critical in determining how autophagy functions in health and disease.

Key Concepts

Over 30
atg
genes have been shown to regulate autophagy.

Autophagy is induced in response to starvation and oxidative stress, enabling cells to recycle macromolecules and degrade damaged organelles.

Autophagy is required for steroid‐triggered removal of larval tissues during
Drosophila melanogaster
development.

Autophagosomes can sequester intracellular pathogens, which evade the cell's phagocytic machinery and traffic them to the lysosome for degradation.

Decreased autophagy leads to an inability to clear protein aggregates and mutant polyglutamine containing proteins from neurons in fly and worm neurodegeneration models.

Induction of autophagy in flies and worms can extend lifespan, whereas its block leads to increased neuronal cell death and reduced lifespan.

Autophagy has a context‐dependent role in tumourigenesis.
Molecular Biology of Breast Cancer
Authors: Caffarel Maria M , Pensa Sara , Wickenden Julie A , Watson Christine J 
Published: November 2016

Abstract

Breast cancer is a common disease affecting approximately 1 in 9 women at some time in their lives. Moreover, it is not a single disease but is characterised by distinct pathological types with different clinical outcomes. In the past decade, considerable progress has been made in understanding these different cancer subtypes at the molecular level. In particular, global gene expression studies have identified five predominant subtypes that have unique expression signatures. Unlike many other cancers, where a hierarchy of genetic mutations that leads to tumourigenesis has been identified, breast tumours have diverse genetic mutations that affect a variety of signalling pathways. Recently, large‐scale whole‐genome sequencing has revealed a set of potential driver mutations for breast cancer. Although some highly successful treatments have been developed, the challenge for the future is the development of individualised therapies that are specific to each patient's tumour type.

Key Concepts

Breast cancer is a heterogeneous disease characterised by distinct pathological types with different outcomes.

Breast tumours have diverse genetic mutations that affect a variety of signalling pathways.

Breast tumours can be classified into different subgroups according to their molecular expression profiles.

It is not clear whether specific molecular pathways establish the subtype of breast cancer or whether different cell types become transformed and give rise to each tumour subtype.

Breast cancer patients would benefit from individual therapeutic regimens designed to treat their particular type of cancer.
Environmental Performance Index
Authors: Hsu Angel , Zomer Alisa 
Published: November 2016

Abstract
The Environmental Performance Index (EPI) ranks 180 countries on nine priority environmental issues in two objectives including protection of human health and maintaining ecosystem vitality. The objective underlying the EPI is to move the environmental debate from emotional and rhetorical arguments to more data‐ and evidence‐based action that facilitates performance tracking and accountability of decision makers. Now in its sixth iteration, the EPI was among the first tools of its kind and is now a standard bearer for comparing and tracking country performance on international policies, including the Sustainable Development Goals (SDGs).
Fading of Affect Associated with Negative Child‐Related Memories Varies by Parental Child Abuse Potential
Authors: Skowronski John J. , Crouch Julie L. , Coley Sarah L. , Sasson Sapir , Wagner Michael F. , Rutledge Ericka , Cote Kreila , Miksys Christie , Milner Joel S. 
Published: November 2016

SummaryPositive memories tend to hold their affective intensity across time better than negative memories, a phenomenon referred to as the fading affect bias (FAB). An initial study explored this bias in the context of parents' affective responses to memories involving their children. Specifically, parents (N = 90 for Study 1) were asked to recall three positive events and three negative events involving their children. Next, parents rated how positively or negatively they felt when each event occurred and at recall. Results revealed that parents at high risk of physical child abuse showed a smaller FAB than low‐risk parents. The smaller FAB effect observed among high‐risk parents occurred largely because affect associated with negative child‐related events faded minimally over time. This risk moderation effect did not emerge in a second study in which parents (N = 90 for Study 2) recalled general events that were not limited to events involving children. Copyright © 2016 John Wiley & Sons, Ltd.