bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dolomitization of the Lower Ordovician Watts Bight Formation of the St. George Group, western Newfoundland: evidence of hydrothermal fluid alterationGeological Survey of Canada Contribution 20080544.
Authors: Conliffe James , Azmy Karem , Knight Ian , Lavoie Denis 
Published: July 2009

The Watts Bight Formation in western Newfoundland consists of a Lower Ordovician succession of shallow-water carbonates and has been extensively dolomitized. These dolomites occur as both replacements and cements and are associated with complex changes in the rock porosity and permeability. Early replacement micritic dolomites (D1) are finely crystalline and indicate that dolomitization began during early stages of diagenesis. The calculated δ18O values of the earliest (D1) dolomitizing fluids (–6.4‰ to –9.5‰ VSMOW, Vienna Standard Mean Ocean Water) fall between the estimated δ18O values of Tremadocian seawater and meteoric waters and suggest mixing-zone dolomitization. A second phase of coarsely crystalline (up to 400 μm) dolomite (D2) replaces D1 dolomite and early calcite and is associated with enhancement in porosity and permeability through the development of intercrystalline pores. A late-stage saddle dolomite (D3) and late burial calcite cements significantly occluded the pores in some horizons. Petrography, fluid inclusions, and geochemistry show that D2 and D3 dolomites formed from warm (65–125 °C) saline (10 to 25 eq. wt.% NaCl + CaCl2) hydrothermal fluids. The calculated δ18Ofluid of D2 ranges from –4.5‰ to 3.6‰ VSMOW, and for D3 dolomites, calculated δ18Ofluid ranges from 1.4‰ to 8.4‰ VSMOW, suggesting an influx of basinal brines. The occurrence of high porosity associated with D2, combined with the laterally sealing tight limestone beds, presence of favourable source rocks, and thermal maturation, may suggest that the Watts Bight carbonates are possible potential hydrocarbon reservoirs and suitable targets for future hydrocarbon exploration in western Newfoundland.
Recent sedimentary legacy of sockeye salmon (Oncorhynchus nerka) and climate change in an ultraoligotrophic, glacially turbid British Columbia nursery lake
Authors: Hill Aaron C. , Stanford Jack A. , Leavitt Peter R. 
Published: July 2009

Paleolimnological studies of sockeye salmon ( Oncorhynchus nerka ) nursery lakes have shown that lake trophic status is often regulated by climate and harvest via marine-derived nutrients (MDN) from adult spawners. However, these controls are not well understood for sockeye nursery lakes in coastal British Columbia, many of which are ultraoligotrophic and glacially turbid. We examined climate, sockeye population dynamics, and sedimentary indicators of lake algal production from 1958 to 2005 using a radioisotope-dated sediment core from Kitlope Lake, British Columbia. Despite high sedimentation rates (~4.7 mm·year–1), significant influence of terrestrial and aquatic organic matter from the main tributary, and the lowest mean (± standard deviation) δ15N (–0.28‰ ± 0.79‰; a proxy for MDN flux) yet reported from a sockeye nursery lake, sedimentary δ15N, C–N ratio, and fossil pigments were coherent with order-of-magnitude changes in sockeye escapements. Moreover, air temperatures were positively correlated with δ15N, indicating a climate influence counteracting declines of MDN import related to declining spawner returns. Despite elevated production potential, Kitlope Lake remains nutrient-limited with a declining sockeye population, and the productivity of this system would benefit from increased sockeye returns.
Spatial and temporal spawning dynamics of native westslope cutthroat trout, Oncorhynchus clarkii lewisi, introduced rainbow trout, Oncorhynchus mykiss, and their hybrids
Authors: Muhlfeld Clint C. , McMahon Thomas E. , Belcer Durae , Kershner Jeffrey L. 
Published: July 2009

We used radiotelemetry to assess spatial and temporal spawning distributions of native westslope cutthroat trout ( Oncorhynchus clarkii lewisi ; WCT), introduced rainbow trout ( Oncorhynchus mykiss ; RBT), and their hybrids in the upper Flathead River system, Montana (USA) and British Columbia (Canada), from 2000 to 2007. Radio-tagged trout (N = 125) moved upriver towards spawning sites as flows increased during spring runoff and spawned in 29 tributaries. WCT migrated greater distances and spawned in headwater streams during peak flows and as flows declined, whereas RBT and RBT hybrids (backcrosses to RBT) spawned earlier during increasing flows and lower in the system. WCT hybrids (backcrosses to WCT) spawned intermediately in time and space to WCT and RBT and RBT hybrids. Both hybrid groups and RBT, however, spawned over time periods that produced temporal overlap with spawning WCT in most years. Our data indicate that hybridization is spreading via long-distance movements of individuals with high amounts of RBT admixture into WCT streams and stepping-stone invasion at small scales by later generation backcrosses. This study provides evidence that hybridization increases the likelihood of reproductive overlap in time and space, promoting extinction by introgression, and that the spread of hybridization is likely to continue if hybrid source populations are not reduced or eliminated.
Negative energy, instability, and AdS–CFT This paper was presented at the Theory CANADA 4 conference, held at Centre de recherches mathématiques, Montréal, Québec, Canada on 4–7 June 2008.
Authors: Copsey Keith , Mann Robert B. 
Published: July 2009

We consider a freely orbifolded AdS5 × S5 and demonstrate that standard boundary conditions allow states of arbitrarily negative energy. These states describe bubbles that are regular up to singularities due to smeared D3-branes. We discuss the evolution of this data and point out that if the usual boundary conditions are enforced such bubbles may never reach infinity.
Low-energy electron elastic scattering from complex atoms: Nd, Eu, and Tm
Authors: Felfli Z. , Msezane A. Z. , Sokolovski D. 
Published: July 2009

The recent Regge-pole methodology, which includes the essential electron correlations, is employed together with a Thomas–Fermi type potential incorporating the vital core-polarization interaction to calculate low-energy (E less than or equal to 1 eV) electron elastic total and Mulholland cross sections for the complex atoms Nd, Eu, and Tm, found to be characterized by subtle Regge resonances, for a fundamental understanding of the mechanism of the near-threshold electron attachment. The binding energies of the complex negative ions Nd–, Eu–, and Tm– formed through the collisions as Regge resonances are extracted for the first time from the resonances and compared with the latest theoretical and experimental values. Ramsauer–Townsend minima, shape resonances, and the Wigner threshold behavior are also obtained.
Effect of midrotation fertilization on growth and specific gravity of loblolly pine
Authors: Antony Finto , Jordan Lewis , Daniels Richard F. , Schimleck Laurence R. , Clark Alexander , Hall Daniel B. 
Published: July 2009

Wood properties and growth were measured on breast-height cores and on disks collected at different heights from a thinned and fertilized midrotation loblolly pine ( Pinus taeda L.) plantation in the lower Coastal Plain of North Carolina. The study was laid out in a randomized complete-block design receiving four levels of nitrogen (N) fertilizer: unfertilized control and 112, 224, and 336 kg/ha plus 28 kg/ha of phosphorus with each treatment. The effect of fertilization was analyzed for the whole-disk and for a 4 year average following fertilization on data collected from breast-height cores and from disks. The fertilization treatments did not significantly affect whole-disk wood properties but significantly increased radial growth. Fertilization rate of 336 kg/ha N significantly reduced 4 year average ring specific gravity and latewood specific gravity. Wood properties of trees that received 112 and 224 kg/ha N were not affected following treatment. There was no height related trend in wood property changes due to fertilization. Fertilization significantly increased ring basal area and earlywood basal area. In summary, there was a decline in wood properties and an increase in basal area growth immediately after fertilization; both depended on the rate of fertilizer applied irrespective of height.
Impact of carbon value on the profitability of slash pine plantations in the southern United States: an integrated life cycle and Faustmann analysis
Authors: Dwivedi Puneet , Alavalapati Janaki R.R. , Susaeta Andres , Stainback Andrew 
Published: July 2009

The emergence of voluntary carbon markets provides an additional income opportunity to nonindustrial private forest (NIPF) landowners because of the carbon sequestered in forest biomass. This study integrates life cycle analysis and the modified Faustmann model to assess the impact of carbon payments on the optimum rotation age and profitability of 1 ha of privately owned but intensely managed slash pine ( Pinus elliottii Engelm.) plantation in the southern United States. Guidelines of the Chicago Climate Exchange were followed for carbon payments. When carbon payments were included, land expectation values (LEVs) were found to be about $1384·ha–1 and $1063·ha–1 for the with and without thinning scenarios, respectively. When payment for carbon sequestered in the live forest biomass was included, LEVs increased to about $2807·ha–1 and $2765·ha–1 for the aforementioned scenarios, respectively. No significant change in the optimum rotation age was observed in the presence of carbon payments. Results suggest that voluntary carbon markets could play a key role in improving the financial returns to NIPF landowners.
Assessing effects of positioning errors and sample plot size on biophysical stand properties derived from airborne laser scanner data
Authors: Gobakken Terje , Næsset Erik 
Published: July 2009

Canopy height distributions were created from small-footprint airborne laser scanner data with an average sampling density of 1.1 points·m–2 collected over 132 sample plots and 61 stands. Field measurements of each plot were carried out within two concentric circles (200 m2 and 300 or 400 m2). The plot positions were altered randomly with Monte Carlo simulations. For various metrics derived from the canopy height distributions, the mean and the standard deviation (SD) of the differences between incorrect plot positions and ground-truth positions were compared. In general, SD was smaller for large field plots than for small plots, and the variation in SD among the Monte Carlo repetitions was smaller for large sample plots. The combined effects of field plot size and sample plot position error on the accuracy of mean tree height (hL), stand basal area (G), and stand volume (V) predicted at stand level using a two-stage procedure combining field training data and laser data were assessed. Standard deviation of the differences between predicted and observed hL was quite stable and of similar size for position errors up to 5 m. However, for G and V the influence of plot position error was more pronounced.
Oak contribution to litter nutrient dynamics in an Appalachian forest receiving elevated nitrogen and dolomite
Authors: Piatek K.B. , Munasinghe P. , Peterjohn W.T. , Adams M.B. , Cumming J.R. 
Published: July 2009

Ecosystem nitrogen (N), phosphorus (P), and calcium (Ca) fluxes are affected by inputs of atmospheric N. Oak litter may additionally affect these fluxes because of its high-lignin content. We analyzed nutrient dynamics in ambient mixed-species litter in an aggrading hardwood stand at the Fernow Experimental Forest in West Virginia. We separated oak from the mix for analysis (oak) and compared it with total litter (all species) to understand how oak affects nutrient fluxes in the litter layer. The study was conducted under ambient atmospheric deposition, under elevated atmospheric deposition, and under elevated deposition plus mitigation with dolomite. N flux between litterfall and 12 months later indicated a net loss in all-species litter of up to 7.3 kg N·ha–1 and a retention of up to 0.6 kg N·ha–1 in oak. P flux included losses in all species in ambient and in dolomite treatments of up to 0.19 kg P·ha–1 and gains of up to 0.12 kg P·ha–1 in oak in all treatments. Oak mineralized Ca at an average across treatments of 4.6 kg Ca·ha–1 compared with 16 kg Ca·ha–1 in all species, with half of that when trees were dormant. Percent immobilization and release over initial litter were greater in oak than in all species, but nutrient fluxes were lower in oak than in all species because of low oak litter mass. Elevated deposition lowered N and increased P immobilization. Dolomite appeared to affect early N dynamics only. With an increase in litterfall mass when forests mature, these effects are also likely to increase.
Potential effects of climate change on ecosystem distribution in Alberta
Authors: Schneider Richard R. , Hamann Andreas , Farr Dan , Wang Xianli , Boutin Stan 
Published: July 2009

We propose a new and relatively simple modification to extend the utility of bioclimatic envelope models for land-use planning and adaptation under climate change. In our approach, the trajectory of vegetation change is set by a bioclimatic envelope model, but the rate of transition is determined by a disturbance model. We used this new approach to explore potential changes in the distribution of ecosystems in Alberta, Canada, under alternative climate and disturbance scenarios. The disturbance model slowed the rate of ecosystem transition, relative to the raw projections of the bioclimatic envelope model. But even with these transition lags in place, a northward shift of grasslands into much of the existing parkland occurred over the 50 years of our simulation. There was also a conversion of 12%–21% of Alberta’s boreal region to parkland. In addition to aspatial projections, our simulations provide testable predictions about where ecosystem changes as a result of climate change are most likely to be initially observed. We also conducted an investigation of model uncertainty that provides an indication of the robustness of our findings and identifies fruitful avenues for future research.
Chapter 11 Physics of Soft Pions and the Lightest Scalars at BES-III
Authors: Bian Jian-Ming , Bytev Vladimir , Chen Ying , Jin Hong-Ying , Jin Shan , Qin Hu , Shen Xiao-Yan , Wu Ning , Xu Guo-Fa , Zhang Zhen-Xia , Zhao Qiang , Zhemchugov Alexey , Zheng Han-Qing , Zhu Shi-Lin , Zou Bing-Song 
Published: July 2009

The following sections are included: Partially Conserved Vector Current (PCAC) and Soft Pions Beyond the Breit–Wigner Description of a Broad Resonance Final State Interaction Theorem and Omnés Solution On the Nature of the Lightest Scalar Resonances
Overexpression of Platelet-Derived Growth Factor-BB Increases Tumor Pericyte Content via Stromal-Derived Factor-1α/CXCR4 Axis
Authors: Song Nan , Huang Yujie , Shi Hubing , Yuan Shaopeng , Ding Yanping , Song Xiaomin , Fu Yan , Luo Yongzhang 
Published: July 2009

Abstract
Platelet-derived growth factor-BB (PDGF-BB) is a well-characterized growth factor displaying potent biological effects on angiogenesis. Recent studies reveal that overexpression of PDGF-BB within tumors results in increased pericyte coverage, suggesting that PDGF-BB signaling is also essential for the cancerous pericyte recruitment process. However, the molecular mechanism underlying this regulation remains obscure. In the current study, we show that tumor-derived PDGF-BB induces SDF-1α expression in endothelial cells (EC), resulting in the formation of SDF-1α chemotaxis gradient, which coincides with the PDGF-BB–induced pericyte recruitment during angiogenesis. PDGF-BB dramatically up-regulates SDF-1α secretion through the activation of PDGFRβ in tumor-associated ECs, whereas this up-regulation can be substantially inhibited by either blockade of the phosphatidylinositol 3-kinase/Akt/mTOR pathway with chemical inhibitors or the inactivation of HIF-1α through small interfering RNA interference. On the other hand, we reveal that SDF-1α can increase pericytes motility in vitro. Blockade of the SDF-1α/CXCR4 axis prevents the PDGF-BB–induced pericyte recruitment not only in three in vitro recruitment models but also in the PDGF-BB–overexpressing tumor xenograft models. These results highlight that the involvement of SDF-1α/CXCR4 axis is essential for the pericyte recruitment within the PDGF-BB–overexpressing tumors and raise the possibility that blockade of the SDF-1α/CXCR4 axis may provide a therapeutic synergy with antiangiogenic molecules that selectively target ECs. [Cancer Res 2009;69(15):6057–64]
Epithelial to Mesenchymal Transition Contributes to Drug Resistance in Pancreatic Cancer
Authors: Arumugam Thiruvengadam , Ramachandran Vijaya , Fournier Keith F. , Wang Huamin , Marquis Lauren , Abbruzzese James L. , Gallick Gary E. , Logsdon Craig D. , McConkey David J. , Choi Woonyoung 
Published: July 2009

AbstractA better understanding of drug resistance mechanisms is required to improve outcomes in patients with pancreatic cancer. Here, we characterized patterns of sensitivity and resistance to three conventional chemotherapeutic agents with divergent mechanisms of action [gemcitabine, 5-fluorouracil (5-FU), and cisplatin] in pancreatic cancer cells. Four (L3.6pl, BxPC-3, CFPAC-1, and SU86.86) were sensitive and five (PANC-1, Hs766T, AsPC-1, MIAPaCa-2, and MPanc96) were resistant to all three agents based on GI50 (50% growth inhibition). Gene expression profiling and unsupervised hierarchical clustering revealed that the sensitive and resistant cells formed two distinct groups and differed in expression of specific genes, including several features of “epithelial to mesenchymal transition” (EMT). Interestingly, an inverse correlation between E-cadherin and its transcriptional suppressor, Zeb-1, was observed in the gene expression data and was confirmed by real-time PCR. Independent validation experiment using five new pancreatic cancer cell lines confirmed that an inverse correlation between E-cadherin and Zeb-1 correlated closely with resistance to gemcitabine, 5-FU, and cisplatin. Silencing Zeb-1 in the mesenchymal lines not only increased the expression of E-cadherin but also other epithelial markers, such as EVA1 and MAL2, and restored drug sensitivity. Importantly, immunohistochemical analysis of E-cadherin and Zeb-1 in primary tumors confirmed that expression of the two proteins was mutually exclusive (P = 0.012). Therefore, our results suggest that Zeb-1 and other regulators of EMT may maintain drug resistance in human pancreatic cancer cells, and therapeutic strategies to inhibit Zeb-1 and reverse EMT should be evaluated. [Cancer Res 2009;69(14):5820–8]
Computational Identification of a p38SAPK-Regulated Transcription Factor Network Required for Tumor Cell Quiescence
Authors: Adam Alejandro P. , George Ajish , Schewe Denis , Bragado Paloma , Iglesias Bibiana V. , Ranganathan Aparna C. , Kourtidis Antonis , Conklin Douglas S. , Aguirre-Ghiso Julio A. 
Published: July 2009

Abstract
The stress-activated kinase p38 plays key roles in tumor suppression and induction of tumor cell dormancy. However, the mechanisms behind these functions remain poorly understood. Using computational tools, we identified a transcription factor (TF) network regulated by p38α/β and required for human squamous carcinoma cell quiescence in vivo. We found that p38 transcriptionally regulates a core network of 46 genes that includes 16 TFs. Activation of p38 induced the expression of the TFs p53 and BHLHB3, while inhibiting c-Jun and FoxM1 expression. Furthermore, induction of p53 by p38 was dependent on c-Jun down-regulation. Accordingly, RNAi down-regulation of BHLHB3 or p53 interrupted tumor cell quiescence, while down-regulation of c-Jun or FoxM1 or overexpression of BHLHB3 in malignant cells mimicked the onset of quiescence. Our results identify components of the regulatory mechanisms driving p38-induced cancer cell quiescence. These may regulate dormancy of residual disease that usually precedes the onset of metastasis in many cancers. [Cancer Res 2009;69(14):5664–72]
Kruppel-Associated Box Domain-Associated Protein-1 as a Latency Regulator for Kaposi's Sarcoma-Associated Herpesvirus and Its Modulation by the Viral Protein Kinase
Authors: Chang Pei-Ching , Fitzgerald Latricia D. , Van Geelen Albert , Izumiya Yoshihiro , Ellison Thomas J. , Wang Don-Hong , Ann David K. , Luciw Paul A. , Kung Hsing-Jien 
Published: July 2009

Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) has been linked to the development of Kaposi's sarcoma, a major AIDS-associated malignancy, and to hematologic malignancies, including primary effusion lymphoma and multicentric Castleman's disease. Like other herpesviruses, KSHV is capable of both latent and lytic replication. Understanding the molecular details associated with this transition from latency to lytic replication is key to controlling virus spread and can affect the development of intervention strategies. Here, we report that Kruppel-associated box domain-associated protein-1 (KAP-1)/transcriptional intermediary factor 1β, a cellular transcriptional repressor that controls chromosomal remodeling, participates in the process of switching viral latency to lytic replication. Knockdown of KAP-1 by small interfering RNA leads to KSHV reactivation mediated by K-Rta, a key transcriptional regulator. In cells harboring latent KSHV, KAP-1 was associated with the majority of viral lytic-gene promoters. K-Rta overexpression induced the viral lytic cycle with concomitant reduction of KAP-1 binding to viral promoters. Association of KAP-1 with heterochromatin was modulated by both sumoylation and phoshorylation. During lytic replication of KSHV, KAP-1 was phosphorylated at Ser824. Several lines of evidence directly linked the viral protein kinase to this post-translational modification. Additional studies showed that this phosphorylation of KAP-1 produced a decrease in its sumoylation, consequently decreasing the ability of KAP-1 to condense chromatin on viral promoters. In summary, the cellular transcriptional repressor KAP-1 plays a role in regulating KSHV latency, and viral protein kinase modulates the chromatin remodeling function of this repressor. [Cancer Res 2009;69(14):5681–9]
Positive Feedback Activation of Estrogen Receptors by the CXCL12-CXCR4 Pathway
Authors: Sauvé Karine , Lepage Julie , Sanchez Mélanie , Heveker Nikolaus , Tremblay André 
Published: July 2009

Abstract
Induction of estrogen-regulated gene transcription by estrogen receptors ERα and ERβ plays an important role in breast cancer development and growth. High expression of the chemokine receptor CXCR4 and its ligand CXCL12/stromal cell-derived factor 1 (SDF-1) has also been correlated with aggressive breast tumor phenotypes. Here, we describe a positive regulatory loop between the CXCR4/SDF-1 signaling pathway and ER transcriptional competence in human breast cancer cells. Treatment of breast carcinoma MCF-7 cells with SDF-1 increased ER transcriptional activity and expression of ER target genes, including SDF-1 itself. These effects were blocked by the antiestrogen ICI-182780 and by CXCR4 silencing and, conversely, estrogen-induced gene expression and growth of MCF-7 cells were impaired on CXCR4 inhibition. Both ERα and ERβ were activated by SDF-1 in the presence of CXCR4 and by overexpression of a constitutively active CXCR4, indicating that CXCR4 signals to both receptors. In particular, ERβ was able to translate the effects of SDF-1 on its own expression, as well as enhance activator protein 1 (AP-1) containing genes cyclin D1 and c-Myc in the presence of tamoxifen. This correlated with an increased ERβ occupancy of responsive promoters at both estrogen-responsive and AP-1 elements. Ser-87, a conserved mitogen-activated protein kinase site in ERβ, was highly phosphorylated by SDF-1, revealing an essential role of the AF-1 domain in response to CXCR4 activation. These results identify a complete autocrine loop between the CXCR4/SDF-1 and ERα/ERβ signaling pathways that dictates ER-dependent gene expression and growth of breast cancer cells. [Cancer Res 2009;69(14):5793–800]