bluuebunny/crossref_metadata_2025_split huggingface dataset:
Getting the biggest birch for the bang: restoring and expanding upland birchwoods in the Scottish Highlands by managing red deer
Authors: Tanentzap Andrew J. , Zou James , Coomes David A. 
Published: May 2013

AbstractHigh deer populations threaten the conservation value of woodlands and grasslands, but predicting the success of deer culling, in terms of allowing vegetation to recover, is difficult. Numerical simulation modeling is one approach to gain insight into the outcomes of management scenarios. We develop a spatially explicit model to predict the responses ofBetulaspp. to red deer (Cervus elaphus) and land management in the Scottish Highlands. Our model integrates a Bayesian stochastic stage‐based matrix model within the framework of a widely used individual‐based forest simulation model, using data collected along spatial and temporal gradients in deer browsing. By initializing our model with the historical spatial locations of trees, we find that densities of juvenile trees (<3 m tall) predicted after 9–13 years closely match counts observed in the field. This is among the first tests of the accuracy of a dynamical simulation model for predicting the responses of tree regeneration to herbivores. We then test the relative importance of deer browsing, ground cover vegetation, and seed availability in facilitating landscape‐level birch regeneration using simulations in which we varied these three variables. We find that deer primarily control transitions of birch to taller (>3 m) height tiers over 30 years, but regeneration also requires suitable ground cover for seedling establishment. Densities of adult seed sources did not influence regeneration, nor did an active management scenario where we altered the spatial configuration of adults by creating “woodland islets”. Our results show that managers interested in maximizing tree regeneration cannot simply reduce deer densities but must also improve ground cover for seedling establishment, and the model we develop now enables managers to quantify explicitly how much both these factors need to be altered. More broadly, our findings emphasize the need for land managers to consider the impacts of large herbivores rather than their densities.
Activating Azides and Alkynes for the Click Reaction with [Cu(aNHC)2I] or [Cu(aNHC)2]+ (aNHC = Triazole‐Derived Abnormal Carbenes): Structural Characterization and Catalytic Properties
Authors: Hohloch Stephan , Scheiffele Damaris , Sarkar Biprajit 
Published: May 2013

AbstractNeutral, iodido‐containing copper(I) complexes [Cu(aNHC)2I] {aNHC = 1‐benzyl‐3‐methyl‐4‐phenyl‐1,2,3‐triazol‐5‐ylidene (for 6) and 3‐methyl‐1‐[2‐(methylthio)phenyl]‐4‐phenyl‐1,2,3‐triazol‐5‐ylidene (for 7)} and cationic, halide‐free copper(I) complexes [Cu(aNHC)2](BF4) {aNHC = 1‐benzyl‐3‐methyl‐4‐phenyl‐1,2,3‐triazol‐5‐ylidene (for 8), 3‐methyl‐1,4‐diphenyl‐1,2,3‐triazol‐5‐ylidene (for 9), 3‐methyl‐1‐[2‐(methylthio)phenyl]‐4‐phenyl‐1,2,3‐triazol‐5‐ylidene (for 10), and 1‐mesityl‐3‐methyl‐4‐phenyl‐1,2,3‐triazol‐5‐ylidene (for 11)}, both containing two monodentate abnormal‐carbene ligands (aNHC), were synthesized from [Cu(CH3CN)4](BF4) and the corresponding triazolium salts. It was possible to selectively synthesize both kinds of complexes by simply variing the counter‐anion of the triazolium salts and keeping the metal precursor the same. All complexes were characterized by elemental analysis and spectroscopic methods. 6 and 11 were studied with single‐crystal X‐ray diffraction analyses. In 6, the copper(I) center is tricoordinated, and its geometry is in between trigonal planar and T‐shaped. In halide‐free 11, the copper(I) center is linearly coordinated by two abnormal‐carbene ligands. All complexes were tested as catalysts in the Huisgen [3+2] cycloaddition reaction between azides and alkynes, and they showed excellent efficiencies under neat conditions. A comparison between the efficiencies of the halide‐containing complexes 6 and 7 and the halide‐free cases 8–11, shows that the halide‐free Cu–aNHC complexes are significantly more efficient than their halide‐containing counterparts. The best catalyst was used for a substrate screening by utilizing a variety of azides and a couple of alkynes. The efficiency of the catalyst was maintained with loadings as low as 0.005 mol‐%. Mechanistic studies were carried out as well.
Small‐Molecule Activation with Molybdenum(0) Complexes Supported by Mixed Imidazol‐2‐Ylidene/Phosphanyl Hybrid Ligands – Electronic and Structural Consequences of Substituting a Phosphane by a Carbene Group
Authors: Gradert Christian , Krahmer Jan , Sönnichsen Frank D. , Näther Christian , Tuczek Felix 
Published: May 2013

AbstractBy employing a series of mixed bi‐ and tridentate N‐heterocyclic carbene (NHC)/phosphane ligands, the new molybdenum(0) carbonyl complexes [Mo(CO)4(CP)] [1, CP = 3‐(2‐diphenylphosphanylethyl)‐1‐ethylimidazol‐2‐ylidene], fac‐[Mo(CO)3(PCP)] [2, PCP = 1,3‐bis(2‐diphenylphosphanylethyl)imidazol‐2‐ylidene], and fac‐[Mo(CO)3(CPC)] [3, CPC = bis(1‐ethyl‐3‐ethyleneimidazol‐2‐ylidene)phenylphosphane] have been synthesized. The compounds were investigated by X‐ray structure analysis and vibrational and NMR spectroscopy in conjunction with DFT calculations. For comparison, the complexes [Mo(CO)4(CC)] [4, CC = di(1‐ethylimidazol‐2‐ylidene)methane], fac‐[Mo(CO)3(dpepp)] [5, dpepp = bis(2‐diphenylphosphanylethyl)phenylphosphane], and [Mo(CO)4(dppp)] [6, dppp = 1,3‐bis(diphenylphosphanyl)propane] have also been prepared and investigated. In contrast to the phosphane donors, which exhibiting metal–ligand backbonding interactions, the π‐acceptor interactions of the carbene moieties are exactly cancelled by π‐donor interactions. The σ‐donor strengths of phosphane and carbene groups, on the other hand, are found to be comparable. The implications of this result with respect to the activation of small molecules (e.g., N2) are discussed.
Redox‐Induced Carbon–Carbon Bond Formation by Using Noninnocent Ligands
Authors: Myers Thomas W. , Yee Gereon M. , Berben Louise A. 
Published: May 2013

AbstractThe control of radical reactions to afford selective carbon–carbon bond formation is a significant synthetic challenge with applications ranging from small‐molecule activation to natural product synthesis. Oxidation of (IP–)2Al(CH3) (1, IP = iminopyridine) with TrBPh4 (Tr = trityl) afforded the C–C coupled product [(IP)(Tr‐IP)Al(CH3)][BPh4] (2) in which the trityl radical and the IP– radical have undergone C–C bond formation. In contrast, oxidation of 1 with TrBArF24 {BArF24 = tetrakis[(3,5‐trifluoromethyl)phenyl]borate} or TrB(C6F5)4 affords cationic [(IP)(IP–)Al(CH3)][BArF24] (3a) or [(IP)(IP–)Al(CH3)][B(C6F5)4] (3b), respectively . The different reaction outcomes provided by the different counteranions of Tr+ imply that a difference in stability of the products or of the intermediate mixed‐valent [(IP)(IP‐)Al(CH3)]+ state exists. We speculate that the most likely factor is the difference in solubility afforded by the different anions of the products that are formed. We also show that the formation of stable, cationic biradical complexes is possible and that these complexes do not undergo C–C radical coupling at the IP ligand. Cationic [(IP–)2Al(OEt2)][BArF24] (4) was obtained by protonolysis of 1 with H(OEt2)2BArF24, and two‐electron oxidation of [(IP2–)2Al]– (5) afforded [(IP–)2Al(thf)][BArF24] (6).
P4 Activation by Lanthanum and Lutetium Naphthalene Complexes Supported by a Ferrocene Diamide Ligand
Authors: Huang Wenliang , Diaconescu Paula L. 
Published: May 2013

AbstractTwo rare‐earth (La and Lu) naphthalene complexes supported by a ferrocene diamide ligand activate P4 under ambient conditions to form M3P7 species exclusively. The resulting complexes feature a Zintl‐type polyphosphide P73– unit stabilized by three lanthanide fragments. The reported metal complexes were characterized by X‐ray crystallography, multinuclear NMR spectroscopy, and elemental analysis.
Is it clean or contaminated soil? Using petrogenic versus biogenic GC-FID chromatogram patterns to mathematically resolve false petroleum hydrocarbon detections in clean organic soils: A crude oil–spiked peat microcosm experiment
Authors: Kelly-Hooper Francine , Farwell Andrea J. , Pike Glenna , Kennedy Jocelyn , Wang Zhendi , Grunsky Eric C. , Dixon D. George 
Published: May 2013

Abstract

The Canadian Council of Ministers of the Environment (CCME) reference method for the Canada-wide standard (CWS) for petroleum hydrocarbon (PHC) in soil provides chemistry analysis standards and guidelines for the management of contaminated sites. However, these methods can coextract natural biogenic organic compounds (BOCs) from organic soils, causing false exceedences of toxicity guidelines. The present 300-d microcosm experiment used CWS PHC tier 1 soil extraction and gas chromatography–flame ionization detector (GC-FID) analysis to develop a new tier 2 mathematical approach to resolving this problem. Carbon fractions F2 (C10–C16), F3 (C16–C34), and F4 (&gt;C34) as well as subfractions F3a (C16–C22) and F3b (C22–C34) were studied in peat and sand spiked once with Federated crude oil. These carbon ranges were also studied in 14 light to heavy crude oils. The F3 range in the clean peat was dominated by F3b, whereas the crude oils had approximately equal F3a and F3b distributions. The F2 was nondetectable in the clean peat but was a significant component in crude oil. The crude oil–spiked peat had elevated F2 and F3a distributions. The BOC-adjusted PHC F3 calculation estimated the true PHC concentrations in the spiked peat. The F2:F3b ratio of less than 0.10 indicated PHC absence in the clean peat, and the ratio of greater than or equal to 0.10 indicated PHC presence in the spiked peat and sand. Validation studies are required to confirm whether this new tier 2 approach is applicable to real-case scenarios. Potential adoption of this approach could minimize unnecessary ecological disruptions of thousands of peatlands throughout Canada while also saving millions of dollars in management costs. Environ Toxicol Chem 2013;32:2197–2206. © 2013 SETAC
Bioavailability of purified subcellular metals to a marine fish
Authors: Guo Feng , Yao Jie , Wang Wen-Xiong 
Published: May 2013

Abstract

In the present study, the authors used a supply of naturally contaminated oysters to investigate how the subcellular metal distribution and the metal burden in prey affected the transfer of metals to a marine fish, the grunt Terapon jarbua. The oysters, Crassostrea hongkongensis, each with different contamination histories, were collected and separated into 3 subcellular fractions: 1) metal-rich granules, 2) cellular debris, and 3) a combined fraction of organelles, heat-denatured proteins, and metallothionein-like proteins, defined as the trophically available metal (TAM). These purified fractions showed a wide range of metal concentrations and were fed to the fish for a period of 7 d at a daily comparable feeding rate of 3% of fish body weight. After 7 d exposure, the newly absorbed metals were mainly distributed in the intestine and liver, indicating a significant tissue-specific trophic transfer, especially for Cd and Cu. The trophic transfer factors (TTFs) showed a sequence of cellular debris &gt;TAM &gt; metal-rich granules, suggesting the impact of subcellular distribution in prey on metal bioavailability. However, significant inverse relationships between the TTFs and the metal concentrations in diets were also found in the present study, especially for Cd and Zn. The subcellular metal compartmentalization might be less important than the metal concentration in prey influencing the trophic transfer. The authors' results have important implications for bioavailability and environmental assessment of dietary metals. Environ Toxicol Chem 2013;32:2109–2116. © 2013 SETAC
The influence of sea level rise and changes in fringing reef morphology on gradients in alongshore sediment transport
Authors: Grady A. E. , Moore L. J. , Storlazzi C. D. , Elias E. , Reidenbach M. A. 
Published: May 2013

AbstractClimate‐change‐induced alterations to coral reef ecosystems, in combination with sea level rise, have the potential to significantly alter wave dissipation across reefs, leading to shifts in alongshore sediment transport gradients and alterations to tropical coastlines. We used Delft3D to model schematized profiles of two reef flat widths based on the south Molokai, Hawaii coast. Simulated anthropogenic modifications include incremental degradation of the reef structure as well as sea level rise. Our findings indicate that sea level rise has a greater relative effect on wave energy flux and alongshore sediment transport over a wide flat, whereas both reef degradation and sea level rise exert similar influence over a narrow flat. These results suggest reefs that vary in width alongshore are more likely to experience changes in alongshore sediment transport gradients, and therefore shifts in shoreline erosion and accretion patterns, than more uniform reef systems.
FRAMING THE WILLINGNESS‐TO‐PAY QUESTION: IMPACT ON RESPONSE PATTERNS AND MEAN WILLINGNESS TO PAY
Authors: Gyrd‐Hansen Dorte , Jensen Mette Lundsby , Kjaer Trine 
Published: May 2013

SUMMARYIn this study, respondents were randomly allocated to three variants of the payment card format and an open‐ended format in order to test for convergent validity. The aim was to test whether preferences (as measured by willingness to pay additional tax) would be affected by framing the willingness‐to‐pay question differently. Results demonstrated that valuations were highly sensitive to whether respondents were asked to express their maximum willingness to pay per month or per year. Another important finding is that the introduction of a binary response filter prior to the payment card follow‐up tends to eliminate the positive aspects of introducing a payment card and produces response patterns that are much in line with those of the open‐ended contingent valuation format. However, although a filter will impact on the distribution of willingness‐to‐pay bids and on the rate of zero and protest bids, the overall impact on the welfare estimate is minor. The outcomes of this study indicate that valuations in the stated preference literature may be, at least in part, a function of the instrument designed to obtain the valuations. Copyright © 2013 John Wiley & Sons, Ltd.
The Dimensions of Expatriate Adjustment
Authors: Haslberger Arno , Brewster Chris , Hippler Thomas 
Published: May 2013

AbstractA narrow and partial theoretical base has limited current concepts of expatriate adjustment and the research based upon them. This conceptual article explores one of the less theorized aspects of expatriate adjustment: the fact that it has multiple dimensions. We conceive of adjustment as a person‐environment relationship that takes place in the three dimensions of cognitions, feelings, and behaviors. Combining these elements takes us one step closer to a comprehensive and more realistic understanding of the nature of expatriate adjustment. We include suggestions for future research that follow from our reconceptualization.
The Association of Meaningfulness, Well‐Being, and Engagement with Absenteeism: A Moderated Mediation Model
Authors: Soane Emma , Shantz Amanda , Alfes Kerstin , Truss Catherine , Rees Chris , Gatenby Mark 
Published: May 2013

AbstractWe theorized that absence from work is a resource‐based process that is related to perceived meaningfulness of work, well‐being, and engagement. Broaden‐and‐build theory (Fredrickson, 1998, 2001) and engagement theory (Bakker, Schaufeli, Leiter, & Taris, 2008; Kahn, 1990) were used to develop a framework for explaining absence. Results of a study of 625 employees and human resource records of subsequent absenteeism data for a three‐month period supported our hypotheses that meaningful work increases engagement with work, and that engagement is associated with low levels of absenteeism. Furthermore, data showed that engagement fully mediated the relationship between meaningfulness and absence, and that well‐being strengthened the relationship between meaningfulness and engagement. The results have implications for understanding the role of individual‐level resources in the workplace, and how meaningfulness, well‐being, and engagement influence absence.
Tournament Compensation Systems, Employee Heterogeneity, and Firm Performance
Authors: Backes‐Gellner Uschi , Pull Kerstin 
Published: May 2013

AbstractTournament compensation systems are widely used in practice and have been extensively analyzed theoretically. However, one major problem has hardly been studied in a company context so far: Although it is theoretically well understood that tournament compensation systems are only effective when employees are homogeneous, it has rarely been analyzed what companies can do when they are confronted with employee heterogeneity. In our article, we derive hypotheses on the performance effects of tournament compensation systems in a context of employee heterogeneity based on tournament and expectancy theory. Using personnel records from incentive travel contests, we are able to show that performance is lower in a situation with employee heterogeneity, but that in heterogeneous tournaments, incentives may still work for a subgroup of employees whom we term the “threshold group.” In addition, we also show how companies manage to design the information disclosure systems necessary to install effective “handicapping” or “league‐building” systems in order to increase the effort‐performance expectancy.
Radially anisotropic structure beneath the Shikoku Basin from broadband surface wave analysis of ocean bottom seismometer records
Authors: Takeo A. , Nishida K. , Isse T. , Kawakatsu H. , Shiobara H. , Sugioka H. , Kanazawa T. 
Published: May 2013

AbstractWe have analyzed broadband surface wave data from ocean bottom seismometers deployed in the Shikoku Basin in the northeastern Philippine Sea to determine the radially anisotropic uppermost mantle structure beneath this oceanic basin. We first applied noise correlation method to continuous microseismic records to obtain phase velocities for fundamental‐mode and first higher‐mode Rayleigh waves and fundamental‐mode Love waves at periods of 7–29 s. At longer periods, we applied an array analysis method to teleseismic surface waves to obtain phase velocities of fundamental‐mode Rayleigh and Love waves at periods of 29–117 s. Using these broadband phase velocity measurements, we have determined the one‐dimensional radially anisotropic structure from the crust to the low velocity zone (LVZ) beneath the Shikoku Basin without assuming a priori structure in the uppermost mantle. The final structural model (SB‐RA10) has a high‐velocity lid from the Moho to a depth of ∼40 km, with an LVZ at greater depths. S wave velocities decrease by 6%–10% at a depth range of ∼40–70 km. This large decrease in velocity suggests that there is either a large difference in grain size between these layers or indicates the presence of partial melt or water in the LVZ. Furthermore, strong radial anisotropy of 4%–5% (VSH>VSV) is observed in the uppermost mantle, which may be stronger in the LVZ.
Influence of viscosity pressure dependence on deep lithospheric tectonics during continental collision
Authors: Gray R. , Pysklywec R. N. 
Published: May 2013

AbstractPrevious geodynamic models of continental collision show that the behavior of the continental lithosphere is strongly influenced by its rheology. We build on previous work by quantitatively investigating with numerical experiments the influence of the pressure dependence of viscosity on the process of tectonic deformation during collision. The models demonstrate how the inclusion of viscosity pressure dependence can quite substantially alter the style of continental mantle lithosphere deformation. At low activation volumes, high convergence rates, and low to moderate initial Moho temperatures, the subduction style of mantle lithosphere deformation is dominant. Increasing the activation volume of mantle material allows the subduction style of deformation to occur at all convergence rates studied in the experiments, at the expense of the subduction‐drip and ablative‐drip styles of deformation. At low activation volumes, high convergence rates, and high initial Moho temperatures, the distributed pure shear style of deformation occurs. With these same conditions, increasing the activation volume of mantle material produces an ablative subduction style of mantle lithosphere deformation. At low activation volumes, low convergence rate, and moderate to high initial Moho temperatures, the mantle lithosphere prefers a convective removal style of deformation; increasing the activation volume here yields an ablative‐drip and distributed pure shear styles of deformation. The results demonstrate that inclusion of the pressure dependence of viscosity—quite often neglected in lithosphere‐scale geodynamic models—can be significant in modulating deformation of the deforming lithosphere.
Regulation of p14ARF expression by HPV‐18 E6 variants
Authors: Vazquez‐Vega Salvador , Sanchez‐Suarez Lilia Patricia , Andrade‐Cruz Rafael , Castellanos‐Juarez Emilio , Contreras‐Paredes Adriana , Lizano‐Soberon Marcela , Garcia‐Carranca Alejandro , Benitez Bribiesca Luis 
Published: May 2013

AbstractA common causative agent for uterine cervical cancer is the human papillomavirus type 18 (HPV‐18) which has three phylogenic variants: Asian‐Amerindian, European, and African. Each variant shows significant molecular differences in the E6 gene. E6 oncoprotein is a negative regulator of tumor suppressor protein p53, hence, this oncoprotein indirectly regulates the expression of tumor‐suppressor p14ARF. p14ARF and p16INK4A genes are overexpressed in—and have been proposed as markers for—HPV‐related cervical cancer. In order to dissect the role of E6 on the regulation of p14ARF expression, separating it from that of other intervening factors, transfection of E6 variants to MCF‐7 cells was performed, assessing cDNA transcript levels by RT‐PCR, whereas p14ARF and p53 expression were evaluated by immunocytochemistry and Western blot. E6 transfected cells differentially expressed transcripts of two molecular forms: E6 and E6*. The ratio of these two forms varied with the transfected E6 variant. With the Asian‐Amerindian variant, the ratio was E6 > E6*, whereas with the European and the African the ratio was E6* > E6. As expected with the E6* construct, E6* transcripts were solely observed. In addition, when E6 > E6* and p53 expression was low, p14ARF was high and when E6* > E6 and p53 expression was high, p14ARF was low. In conclusion, each E6 variant distinctively affects p53 levels and consequently p14ARF expression, finding that could be related with the differences in oncogenic effect of infection with the diverse high‐risk HPV variants. J. Med. Virol. 85:1215–1221, 2013. © 2013 Wiley Periodicals, Inc.