bluuebunny/crossref_metadata_2025_split huggingface dataset:
The impact of climate change uncertainty on California's vegetation and adaptation management
Authors: Thorne James H. , Choe Hyeyeong , Boynton Ryan M. , Bjorkman Jacquelyn , Albright Whitney , Nydick Koren , Flint Alan L. , Flint Lorraine E. , Schwartz Mark W. 
Published: December 2017

AbstractThe impacts of different emission levels and climate change conditions to landscape‐scale natural vegetation could have large repercussions for ecosystem services and environmental health. We forecast the risk‐reduction benefits to natural landscapes of lowering business‐as‐usual greenhouse gas emissions by comparing the extent and spatial patterns of climate exposure to dominant vegetation under current emissions trajectories (Representative Concentration Pathway, RCP8.5) and envisioned Paris Accord target emissions (RCP4.5). This comparison allows us to assess the ecosystem value of reaching targets to keep global temperature warming under 2°C. Using 350,719 km2 of natural lands in California, USA, and the mapped extents of 30 vegetation types, we identify each type's current bioclimatic envelope by the frequency with which it occupies current climate conditions. We then map the trajectory of each pixel's climate under the four climate futures to quantify areas expected to fall within, become marginal to (outside a 95% probability contour), or move beyond their current climate conditions by the end of the 21st century. In California, these four future climates represent temperature increases of 1.9–4.5°C and a −24.8 to +22.9% change in annual precipitation by 2100. From 158,481 to 196,493 km2 (45–56%) of California's natural vegetation is predicted to become highly climatically stressed under current emission levels (RCP8.5) under the drier and wetter global climate models, respectively. Vegetation in three California ecoregions critical to human welfare, southwestern CA, the Great Valley, and the Sierra Nevada Mountains, becomes >50% impacted, including 68% of the lands around Los Angeles and San Diego. However, reducing emissions to RCP4.5 levels reduces statewide climate exposure risk by 86,382–99,726 km2. These projections are conservative baseline estimates because they do not account for amplified drought‐related mortality, fires, and beetle outbreaks that have been observed during the current five‐year drought. However, these results point to the landscape benefits of emission reductions.
A new application of principal response curves for summarizing abrupt and cyclic shifts of communities over space
Authors: Auber Arnaud , Travers‐Trolet Morgane , Villanueva Maria Ching , Ernande Bruno 
Published: December 2017

AbstractThere is a growing need to easily describe and synthesize the dynamics of ecosystems’ components in space and time. Most multivariate analyses provide ordination diagrams or biplots that are too cluttered to allow simple reading and are unfamiliar to most users. To overcome such difficulties, a novel application of principal response curves (PRCs) is proposed. Principal response curves are traditionally used to assess treatment effects on community structure measured repeatedly over time. In this new application, the tested factor and the repeated‐observation axis are replaced by time and space, respectively. The georeferencing of sampling sites permits to produce an easy‐to‐read map that summarizes both the temporal dynamics of the community and the contribution of each species to these dynamics at each sampling site. A 24‐yr‐long time series of scientific surveys monitoring 77 fish and cephalopod species in the Eastern English Channel is used to illustrate the novel application of the PRC method. This new application could prove a relevant tool for the ecosystem approach to human activities management by providing spatialized indicators of community changes, as spatial monitoring tools are increasingly recommended for measuring the effectiveness of management actions.
Long‐term population dynamics in a multi‐species assemblage of large herbivores in East Africa
Authors: Kiffner Christian , Rheault Helena , Miller Elizabeth , Scheetz Tanner , Enriquez Vivien , Swafford Rachelle , Kioko John , Prins Herbert H. T. 
Published: December 2017

AbstractWildlife population declines in Africa are widespread. However, species‐specific population trends and dynamics in mammal community composition have rarely been described over long time periods. To describe population trends of 13 large herbivore species in Lake Manyara National Park (Tanzania) from 1959 to 2016 and to discover whether the herbivore community structure changed, we used general additive models and additional statistical methods to detect structural changes in the time series. Population dynamics were non‐linear and population growth rates were not correlated with precipitation anomalies. Relatively steep population declines of three megaherbivores occurred during the 1980s and early 1990s, resulting in severe reductions in African elephant and buffalo populations and the local extinction of black rhinoceros. These declines coincided with reported peaks of illegal hunting of these species and expansion of agriculture at the periphery of the park. Population densities of elephant and buffalo seem to have stabilized in recent times, yet have not recovered to previous densities. In contrast, eight species (giraffe, zebra, waterbuck, wildebeest, warthog, impala, bushbuck, and baboon) have apparently fared well (similar or higher densities in most recent compared to first decade), despite having undergone substantial fluctuations over the past 58 yr. Population fluctuations in these species were likely caused by disease outbreaks, heavy bush encroachment, and reduced competition with buffalo. Possibly, declines in megaherbivore densities (mainly elephants) facilitated bush encroachment. Albeit grazers are still dominating in the herbivore community, the proportion of browsers is currently increasing, likely encouraged by dense vegetation in the shrub layer in large parts of the park. Overall, herbivore biomass density has declined by ~40% compared to the baseline estimate in the first decade of the time series. Our analyses and ancillary information provide evidence that this overall decline in the herbivore assemblage was triggered by human‐induced reductions in megaherbivore population densities during the 1980s, either through excessive poaching, insularization of the park, or both. Likely, this had cascading and interacting effects on the vegetation structure and the herbivore assemblage. Thus, legacy effects of ineffective megaherbivore conservation efforts 30 yr ago are likely still affecting the ecology of this national park.
Historical and recent land use affects ecosystem functions in subtropical grasslands in Brazil
Authors: Leidinger Jan L. G. , Gossner Martin M. , Weisser Wolfgang W. , Koch Christiane , Rosadio Cayllahua Zully L. , Podgaiski Luciana R. , Duarte Marcelo M. , Araújo Ademir S. F. , Overbeck Gerhard E. , Hermann Julia‐Maria , Kollmann Johannes , Meyer Sebastian T. 
Published: December 2017

AbstractLand‐use changes such as conversion of semi‐natural grasslands to agriculture, silviculture, or high‐intensity pastures affect biodiversity and ecosystem functions and services. However, which ecosystem functions are affected when highly diverse grasslands are converted remains largely unknown. As a model system, we studied 80 grasslands in Rio Grande do Sul, southern Brazil, comprising exceptionally diverse permanent grasslands that are traditionally managed with burning of accumulated biomass and moderate grazing, and four additional grassland types with different present or historical management: permanent grasslands with reduced or increased current management intensity and secondary grasslands after past agricultural or silvicultural use. We measured ten ecosystem functions covering all major below‐ and aboveground ecosystem components and the processes that link them, using the novel rapid ecosystem function assessment approach. Ecosystem functions included primary and secondary production, and species interactions, that is, herbivory, pollination, predation, seed dispersal, and decomposition. Ecosystem functions differed significantly among grassland types, most distinctly between permanent and secondary grasslands. Historical land‐use changes to agriculture and silviculture led to altered ecosystem functions even after reconversion to grassland, including lower primary and secondary production, lower decomposition, lower seed dispersal capabilities, and higher invertebrate herbivory. Current management practices explained additional variation in some ecosystem functions, including strong positive effects of intensified management on secondary production. Other ecosystem functions such as pollination and predation were not affected. The findings suggest that conversion of grasslands to more intensive land‐use types has long‐lasting consequences for some ecosystem functions, with effects persisting even many years after reconversion, resulting in changes in the ecosystem services provided by these grasslands.
Predicting the bioavailability of sediment-bound uranium to the freshwater midge (Chironomus dilutus) using physicochemical properties
Authors: Crawford Sarah E. , Lofts Stephen , Liber Karsten 
Published: December 2017

Abstract

Assessment of uranium (U)-contaminated sediment is often hindered by the inability to accurately account for the physicochemical properties of sediment that modify U bioavailability. The present goal was to determine whether sediment-associated U bioavailability could be predicted over a wide range of conditions and sediment properties using simple regressions and a geochemical speciation model, the Windermere Humic Aqueous Model (WHAM7). Data from a U-contaminated field sediment bioaccumulation test, along with previously published bioaccumulation studies with U-spiked field and formulated sediments, were used to examine the models. Observed U concentrations in Chironomus dilutus larvae exposed to U-spiked and U-contaminated sediments correlated well (r2 &gt; 0.74, p &lt; 0.001) with the WHAM-calculated concentration of U bound to humic acid, indicating that humic acid may be a suitable surrogate for U binding sites (biotic ligands) in C. dilutus larvae. Subsequently, the concentration of U in C. dilutus was predicted with WHAM7 by numerically optimizing the equivalent mass of humic acid per gram of organism. The predicted concentrations of U in C. dilutus larvae exposed to U-spiked and U-contaminated field sediment compared well with the observed values, where one of the regression models provided a slightly better fit (mean absolute error = 18.1 mg U/kg dry wt) than WHAM7 (mean absolute error = 34.2 mg U/kg dry wt). The regression model provides a predictive capacity with a minimal number of variables, whereas WHAM7 provides additional complementary insight into the chemical variables influencing the speciation, sorption, and bioavailability of U in sediment. The present results indicate that physicochemical properties of sediment can be used to account for variability in U bioavailability as measured through bioaccumulation in chironomids exposed to U-contaminated sediments. Environ Toxicol Chem 2018;37:1146–1157. © 2017 SETAC
Mineral chemistry, bulk rock geochemistry, and S‐isotope signature of lode‐gold mineralization in the Bétaré Oya gold district, south‐east Cameroon
Authors: Vishiti Akumbom , Suh Cheo Emmanuel , Lehmann Bernd , Shemang Elisha Mutum , Ngome Njumbe Lionel Junior , Nshanji Nfor Jones , Chinjo Fonkwo Edmond , Mongwe Oben Yoland , Egbe Ashu Jones , Petersen Sven 
Published: December 2017

Lode‐gold mineralization in the Bétaré Oya gold district is related to a series of quartz–sulphide veins that define a steeply dipping NNE–SSW‐trending brittle–ductile shear zone. The veins transect metasedimentary sequences in the vicinity of small granitic intrusions. Quartz veins range from barren (massive quartz) to mineralized with textures that vary from foliated, sheared, vuggy, fractured, and sugary to brecciated with inclusions of altered wall rock. They contain gold, pyrite, and galena in addition to chalcopyrite and both hypogene and supergene haematite and covellite. Parameters that consistently define primary gold mineralization in the area include silicification, sulphidation, sericitization, K‐feldspar alteration, haematitization, and carbonatization. Gold grains recovered from heavy mineral concentrate and grains that occur as inclusions in pyrite were characterized by microchemical methods. The gold grains are zoned and exhibit a simple internal structure of partly deformed and leached rims and high‐purity intragranular veinlets. Gold is alloyed with Ag; gold fineness varies between 859 and 877 in the core and from 958 to 997 in the leached rims. Inclusions of gold in pyrite cluster between 875 and 900. Pyrite has up to 0.59 wt% Au, and other trace elements occur in low quantities but for Pb (0.13 wt%), Ag (1.36 wt%), and Sb (1.63 wt%). The bulk trace element signature of the veins is characterized by Au, Ag, As, Bi, Ba, Cr, Cu, Mn, Pb, Sb, Sr, V, W, Zn, and Zr. This depicts a geochemical association of Au ± Cu ± Bi ± As ± Pb. The occurrence of Au as well as elevated Pb and Zn could suggest a granitic source for the ore‐bearing fluid. The auriferous quartz veins are characterized by a widespread in δ34S from 2.8 to 14.9‰ pointing to multiple sources of sulphur in the system, perhaps a mixture of sulphur from the metasedimentary and the granitic rocks.
Myelin extracellular leaflet compaction requires apolipoprotein D membrane management to optimize lysosomal‐dependent recycling and glycocalyx removal
Authors: García‐Mateo Nadia , Pascua‐Maestro Raquel , Pérez‐Castellanos Alberto , Lillo Concepción , Sanchez Diego , Ganfornina Maria D. 
Published: December 2017

AbstractTo compact the extracellular sides of myelin, an important transition must take place: from membrane sliding, while building the wraps, to membrane adhesion and water exclusion. Removal of the negatively charged glycocalyx becomes the limiting factor in such transition. What is required to initiate this membrane‐zipping process? Knocking‐out the Lipocalin Apolipoprotein D (ApoD), essential for lysosomal functional integrity in glial cells, results in a specific defect in myelin extracellular leaflet compaction in peripheral and central nervous system, which results in reduced conduction velocity and suboptimal behavioral outputs: motor learning is compromised. Myelination initiation, growth, intracellular leaflet compaction, myelin thickness or internodal length remain unaltered. Lack of ApoD specifically modifies Plp and P0 protein expression, but not Mbp or Mag. Late in myelin maturation period, ApoD affects lipogenic and growth‐related, but not stress‐responsive, signaling pathways. Without ApoD, the sialylated glycocalyx is maintained and ganglioside content remains high. In peripheral nervous system, Neu3 membrane sialidase and lysosomal Neu1 are coordinately expressed with ApoD in subsets of Schwann cells. ApoD‐KO myelin becomes depleted of Neu3 and enriched in Fyn, a kinase with pivotal roles in transducing axon‐derived signals into myelin properties. In the absence of ApoD, partial permeabilization of lysosomes alters Neu1 location as well. Exogenous ApoD rescues ApoD‐KO hypersialylated glycocalyx in astrocytes, demonstrating that ApoD is necessary and sufficient to control glycocalyx composition in glial cells. By ensuring lysosomal functional integrity and adequate subcellular location of effector and regulatory proteins, ApoD guarantees the glycolipid recycling and glycocalyx removal required to complete myelin compaction.
Task‐related effective connectivity reveals that the cortical rich club gates cortex‐wide communication
Authors: Senden Mario , Reuter Niels , van den Heuvel Martijn P. , Goebel Rainer , Deco Gustavo , Gilson Matthieu 
Published: December 2017

AbstractHigher cognition may require the globally coordinated integration of specialized brain regions into functional networks. A collection of structural cortical hubs—referred to as the rich club—has been hypothesized to support task‐specific functional integration. In the present paper, we use a whole‐cortex model to estimate directed interactions between 68 cortical regions from functional magnetic resonance imaging activity for four different tasks (reflecting different cognitive domains) and resting state. We analyze the state‐dependent input and output effective connectivity (EC) of the structural rich club and relate these to whole‐cortex dynamics and network reconfigurations. We find that the cortical rich club exhibits an increase in outgoing EC during task performance as compared with rest while incoming connectivity remains constant. Increased outgoing connectivity targets a sparse set of peripheral regions with specific regions strongly overlapping between tasks. At the same time, community detection analyses reveal massive reorganizations of interactions among peripheral regions, including those serving as target of increased rich club output. This suggests that while peripheral regions may play a role in several tasks, their concrete interplay might nonetheless be task‐specific. Furthermore, we observe that whole‐cortex dynamics are faster during task as compared with rest. The decoupling effects usually accompanying faster dynamics appear to be counteracted by the increased rich club outgoing EC. Together our findings speak to a gating mechanism of the rich club that supports fast‐paced information exchange among relevant peripheral regions in a task‐specific and goal‐directed fashion, while constantly listening to the whole network.
MiRNALet‐7a mediates prostate cancer PC‐3 cell invasion, migration by inducing epithelial‐mesenchymal transition through CCR7/MAPK pathway
Authors: Tang Guanlin , Du Ruoyang , Tang Zhaobing , Kuang Youlin 
Published: December 2017

AbstractProstate cancer is one of the most common malignancies in older men. Recent evidence has demonstrated microRNA (miRNA) Let‐7a expression decreased in prostate cancer, while the expression of CC chemokine receptor type 7 (CCR7) increased. In this study, we investigated whether CCR7 overexpression was associated with a decrease in the expression of miRNA Let‐7a in invasion and metastasis of prostate cancer cell. Synthetic Let‐7a mimics and Let‐7a inhibitors were transfected into prostate cancer PC‐3 cells, respectively. Then Western blot was used to detect the expression of CCR7, ERK, p38, MMP‐9, and Epithelial‐Mesenchymal Transition (EMT)‐related proteins. Matrigel invasion assays were performed to assess the migratory and invasive activities of PC3 cells. To confirm the fact that 3′UTR of CCR7 is a direct target of Let‐7a, a luciferase assay for the reporter gene expressing the Let‐7a binding sites of CCR7 3′UTR was used. Synthetic Let‐7a mimics decreased prostate cancer cell migration and invasion, as well as the expression of CCR7, phospho‐p38, phospho‐ERK1/2, MMP‐9, N‐cadherin, and Snail in PC‐3 cells. The Let‐7a inhibitors reversed the effects of Let‐7a on PC‐3 cells. The 3′UTR of CCR7 was confirmed as a direct target of Let‐7a by using the luciferase assay. All findings demonstrated that Let‐7a/CCR7 axis regulated EMT progress in prostate cancer cells and mediated the tumor cell invasion and migration process via activation of P38/ERK signal pathway. Our results suggested that the therapeutic potential of Let‐7a as an antitumor and antimetastatic manager in prostate cancer and CCR7 may be regarded as a therapeutic target for the prostate cancer treatment.
Proliferation and apoptosis of rheumatoid arthritis fibroblast‐like synoviocytes following signal transducer and activator of transcription 3 RNA interference delivery
Authors: Sun Xuehui , Han Yun , Liu Ying , Tang Yanchun , Wang Jibo 
Published: December 2017

AbstractObjectiveIn this study, we investigated the effects of delivering small interfering RNA (siRNA) for efficient STAT3 downregulation on propagation and apoptosis of rheumatoid arthritis fibroblast‐like synoviocytes (RA‐FLS).MethodsThe FLSs were transfected with three different siRNAs. RNAi‐1 was selected for further experiments. The expression levels of both STAT3 messenger RNA (mRNA) and its protein were detected by a real‐time polymerase chain reaction and Western blot analysis. The proliferation of FLSs was examined by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay. The apoptosis of FLSs was examined by flow cytometry. The expression levels of cell apoptotic‐related genes
Bcl‐2,
Bax, and caspase‐3 were detected by Western blot analysis.ResultsRNAi‐1 was selected as the RNAi group for its lowest expression levels of STAT3 mRNA. In RNAi group, the proliferation of synoviocytes was much lower and the apoptosis rate was significantly higher. FLSs of RNAi‐1 group showed significantly lower expression level of apoptotic‐inhibiting gene
Bcl‐2 and significantly higher expression levels of proapoptotic gene
Bax and apoptotic protease caspase‐3.ConclusionTransfection with targeted STAT3 recombinant plasmids effectively inhibited the expression of
STAT3 mRNA and its protein in RA‐FLSs. RNAi‐mediated silencing of
STAT3 reduced the proliferation and promoted the apoptosis of FLSs.
Murine models of osteosarcoma: A piece of the translational puzzle
Authors: Walia Mannu K. , Castillo‐Tandazo Wilson , Mutsaers Anthony J. , Martin Thomas John , Walkley Carl R. 
Published: December 2017

AbstractOsteosarcoma (OS) is the most common cancer of bone in children and young adults. Despite extensive research efforts, there has been no significant improvement in patient outcome for many years. An improved understanding of the biology of this cancer and how genes frequently mutated contribute to OS may help improve outcomes for patients. While our knowledge of the mutational burden of OS is approaching saturation, our understanding of how these mutations contribute to OS initiation and maintenance is less clear. Murine models of OS have now been demonstrated to be highly valid recapitulations of human OS. These models were originally based on the frequent disruption of p53 and Rb in familial OS syndromes, which are also common mutations in sporadic OS. They have been applied to significantly improve our understanding about the functions of recurrently mutated genes in disease. The murine models can be used as a platform for preclinical testing and identifying new therapeutic targets, in addition to testing the role of additional mutations in vivo. Most recently these models have begun to be used for discovery based approaches and screens, which hold significant promise in furthering our understanding of the genetic and therapeutic sensitivities of OS. In this review, we discuss the mouse models of OS that have been reported in the last 3‐5 years and newly identified pathways from these studies. Finally, we discuss the preclinical utilization of the mouse models of OS for identifying and validating actionable targets to improve patient outcome.