bluuebunny/crossref_metadata_2025 huggingface dataset:
Atmospheric test of the J(BrONO2)/kBrO+NO2 ratio: implications for total stratospheric Bry and bromine-mediated ozone loss
Authors: Kreycy S. , Camy-Peyret C. , Chipperfield M. P. , Dorf M. , Feng W. , Hossaini R. , Kritten L. , Werner B. , Pfeilsticker K.
Published: July 2013

Abstract. We report on time-dependent O3, NO2 and BrO profiles measured by limb observations of scattered skylight in the stratosphere over Kiruna (67.9° N, 22.1° E) on 7 and 8 September 2009 during the autumn circulation turn-over. The observations are complemented by simultaneous direct solar occultation measurements around sunset and sunrise performed aboard the same stratospheric balloon payload. Supporting radiative transfer and photochemical modelling indicate that the measurements can be used to constrain the ratio J(BrONO2)/kBrO+NO2, for which at T = 220 ± 5 K an overall 1.7 (+0.4 −0.2) larger ratio is found than recommended by the most recent Jet Propulsion Laboratory (JPL) compilation (Sander et al., 2011). Sensitivity studies reveal the major reasons are likely to be (1) a larger BrONO2 absorption cross-section σBrONO2, primarily for wavelengths larger than 300 nm, and (2) a smaller kBrO+NO2 at 220 K than given by Sander et al. (2011). Other factors, e.g. the actinic flux and quantum yield for the dissociation of BrONO2, can be ruled out. The observations also have consequences for total inorganic stratospheric bromine (Bry) estimated from stratospheric BrO measurements at high NOx loadings, since the ratio J(BrONO2)/kBrO+NO2 largely determines the stratospheric BrO/Bry ratio during daylight. Using the revised J(BrONO2)/kBrO+NO2 ratio, total stratospheric Bry is likely to be 1.4 ppt smaller than previously estimated from BrO profile measurements at high NOx loadings. This would bring estimates of Bry inferred from organic source gas measurements (e.g. CH3Br, the halons, CH2Br2, CHBr3, etc.) into closer agreement with estimates based on BrO observations (inorganic method). The consequences for stratospheric ozone due to the revised J(BrONO2)/kBrO+NO2 ratio are small (maximum −0.8%), since at high NOx (for which most Bry assessments are made) the enhanced ozone loss by overestimating Bry is compensated for by the suppressed ozone loss due to the underestimation of BrO/Bry with a smaller J(BrONO2)/kBrO+NO2 ratio.
The initiation of Neoproterozoic "snowball" climates in CCSM3: the influence of paleo-continental configuration
Authors: Liu Y. , Peltier W. R. , Yang J. , Vettoretti G.
Published: July 2013

Abstract. We identify the "hard snowball" bifurcation point at which total sea ice cover of the oceans is expected by employing the comprehensive coupled climate model CCSM3 for two realistic Neoproterozoic continental configurations, namely a low-latitude configuration appropriate for the 720 Ma Sturtian glaciation and a higher southern latitude configuration more appropriate for the later 635 Ma Marinoan glaciation. We find that for the same total solar insolation (TSI) and atmospheric CO2 concentration (pCO2), the most recent continental configuration is characterized by colder climate than the 720 Ma continental configuration and enters the hard snowball state more easily on account of the following four factors: the low heat capacity of land in the south polar region, the higher albedo of the snow covered land compared to that of sea ice, the more negative net cloud forcing near the ice front in the Northern Hemisphere (NH), and more importantly, the more efficient sea ice transport towards the equator in the NH due to the absence of blockage by continents. Beside the paleogeography, we also find the optical depth of aerosol to have a significant influence on this important bifurcation point. When the high value (recommended by CCSM3 but demonstrated to be a significant overestimate) is employed, the critical values of pCO2, beyond which a hard snowball will be realized, are between 80–90 ppmv and 140–150 ppmv for the Sturtian and Marinoan continental configurations, respectively. However, if a lower value is employed that enables the model to approximately reproduce the present-day climate, then the critical values of pCO2 become 50–60 ppmv and 100–110 ppmv for the two continental configurations, respectively. All of these values are higher than previously obtained for the present-day geography (17–35 ppmv) using the same model, primarily due to the absence of vegetation, but are much lower than that obtained previously for the 635 Ma continental configuration using the ECHAM5/MPI-OM model in its standard configuration (∼500 ppmv). However, when the sea ice albedo in that model was reduced from 0.75 to a more appropriate value of 0.45, the critical pCO2 becomes ∼204 ppmv, closer to but still higher than the values obtained here. Our results are similar to those obtained with the present-day geography (70–100 ppmv) when the most recent version of the NCAR model, CCSM4, is employed.
Automated field detection of rock fracturing, microclimate, and diurnal rock temperature and strain fields
Authors: Warren K. , Eppes M.-C. , Swami S. , Garbini J. , Putkonen J.
Published: July 2013

Abstract. The rates and processes that lead to non-tectonic rock fracture on the Earth's surface are widely debated but poorly understood. Few, if any, studies have made the direct observations of rock fracturing under natural conditions that are necessary to directly address this problem. An instrumentation design that enables concurrent high spatial and temporal monitoring resolution of (1) diurnal environmental conditions of a natural boulder and its surroundings in addition to (2) the fracturing of that boulder under natural full-sun exposure is described herein. The surface of a fluvially transported granite boulder was instrumented with (1) six acoustic emission (AE) sensors that record micro-crack associated, elastic wave-generated activity within the three-dimensional space of the boulder, (2) eight rectangular rosette foil strain gages to measure surface strain, (3) eight thermocouples to measure surface temperature, and (4) one surface moisture sensor. Additionally, a soil moisture probe and a full weather station that measures ambient temperature, relative humidity, wind speed, wind direction, barometric pressure, insolation, and precipitation were installed adjacent to the test boulder. AE activity was continuously monitored by one logger while all other variables were acquired by a separate logger every 60 s. The protocols associated with the instrumentation, data acquisition, and analyses are discussed in detail. During the first four months, the deployed boulder experienced almost 12 000 AE events, the majority of which occur in the afternoon when temperatures are decreasing. This paper presents preliminary data that illustrates data validity and typical patterns and behaviors observed. This system offers the potential to (1) obtain an unprecedented record of the natural conditions under which rocks fracture and (2) decipher the mechanical processes that lead to rock fracture at a variety of temporal scales under a range of natural conditions.
Evaluation of areal precipitation estimates based on downscaled reanalysis and station data by hydrological modelling
Authors: Duethmann D. , Zimmer J. , Gafurov A. , Güntner A. , Kriegel D. , Merz B. , Vorogushyn S.
Published: July 2013

Abstract. In data sparse mountainous regions it is difficult to derive areal precipitation estimates. In addition, their evaluation by cross validation can be misleading if the precipitation gauges are not in representative locations in the catchment. This study aims at the evaluation of precipitation estimates in data sparse mountainous catchments. In particular, it is first tested whether monthly precipitation fields from downscaled reanalysis data can be used for interpolating gauge observations. Secondly, precipitation estimates from this and other methods are evaluated by comparing simulated and observed discharge, which has the advantage that the data are evaluated at the catchment scale. This approach is extended here in order to differentiate between errors in the overall bias and the temporal dynamics, and by taking into account different sources of uncertainties. The study area includes six headwater catchments of the Karadarya Basin in Central Asia. Generally the precipitation estimate based on monthly precipitation fields from downscaled reanalysis data showed an acceptable performance, comparable to another interpolation method using monthly precipitation fields from multi-linear regression against topographical variables. Poor performance was observed in only one catchment, probably due to mountain ridges not resolved in the model orography of the regional climate model. Using two performance criteria for the evaluation by hydrological modelling allowed a more informed differentiation between the precipitation data and showed that the precipitation data sets mostly differed in their overall bias, while the performance with respect to the temporal dynamics was similar. Our precipitation estimates in these catchments are considerably higher than those from continental- or global-scale gridded data sets. The study demonstrates large uncertainties in areal precipitation estimates in these data sparse mountainous catchments. In such regions with only very few precipitation gauges but high spatial variability of precipitation, important information for evaluating precipitation estimates may be gained by hydrological modelling and a comparison to observed discharge.
Comparison of different evaporation estimates over the African continent
Authors: Trambauer P. , Dutra E. , Maskey S. , Werner M. , Pappenberger F. , van Beek L. P. H. , Uhlenbrook S.
Published: July 2013

Abstract. Evaporation is a key process in the water cycle, with implications ranging from water management, to weather forecast and climate change assessments. The estimation of continental evaporation fluxes is complex and typically relies on continental-scale hydrological or land-surface models. However, it appears that most global or continental-scale hydrological models underestimate evaporative fluxes in some regions of Africa, and as a result overestimate stream flow. Other studies suggest that land-surface models may overestimate evaporative fluxes. In this study, we computed actual evaporation for the African continent using a continental version of the global hydrological model PCR-GLOBWB, which is based on a water balance approach. Results are compared with other independently computed evaporation products: the evaporation results from the ECMWF reanalysis ERA-Interim and ERA-Land (both based on the energy balance approach), the MOD16 evaporation product, and the GLEAM product. Three other alternative versions of the PCR-GLOBWB hydrological model were also considered. This resulted in eight products of actual evaporation, which were compared in distinct regions of the African continent spanning different climatic regimes. Annual totals, spatial patterns and seasonality were studied and compared through visual inspection and statistical methods. The comparison shows that the representation of irrigation areas has an insignificant contribution to the actual evaporation at a continental scale with a 0.5° spatial resolution. The choice of meteorological forcing data has a larger effect on the evaporation results, especially in the case of the precipitation input as different precipitation input resulted in significantly different evaporation in some of the studied regions. ERA-Interim evaporation is generally the highest of the selected products followed by ERA-Land evaporation. The satellite based products (GLEAM and MOD16) do not show regular behaviour when compared to the other products, though this depends on the region and the season considered. The results from this study allow for a better understanding of the differences between products in each climatic region. Through an improved understanding of the causes of differences between these products and their uncertainty, this study provides information to improve the quality of evaporation products for the African continent and, consequently, leads to improved water resources assessments at regional scale.
Impacts of climate and forest changes on streamflow and water balance in a mountainous headwater stream in Southern Alberta
Authors: Mahat V. , Anderson A.
Published: July 2013

Abstract. Rivers in Southern Alberta are vulnerable to climate change because much of the river water originates as snow in the eastern slopes of the Rocky Mountains. Changes in likelihood of forest disturbance (wildfire, insects, logging, etc.) may also have impacts that are compounded by climate change. This study evaluates the impacts of climate and forest changes on streamflow in the upper parts of the Oldman River in Southern Alberta using a conceptual hydrological model, HBV-EC in combination with a stochastic weather generator (LARS-WG) driven by GCM (Global Climate Model) output climate data. Three climate change scenarios (A1B, A2 and B1) are selected to cover the range of possible future climate conditions (2020s, 2050s, and 2080s). GCM projected less than a 10% increase in precipitation in winter and a similar amount of precipitation decrease in summer. These changes in projected precipitation resulted in up to a 200% (9.3 mm) increase in winter streamflow in February and up to a 63% (31.2 mm) decrease in summer flow in June. This amplification is mostly driven by the projected increase in temperature that is predicted to melt winter snow earlier, possibly resulting in lower water availability in the snowmelt dominated regions during the summer. Uncertainty analysis was completed using a guided GLUE (generalized likelihood uncertainty estimation) approach to obtain the best 100 parameter sets and associated ranges of streamflows. The impacts of uncertainty were higher in spring and summer flows than in winter and fall flows. Forest change compounded the climate change impact by increasing winter flow; however, it did not reduce the summer flow.
Herding and Speculation in the Crude Oil Market
Authors: Brunetti Celso , Bykahin Bahattin , Harris Jeffrey H.
Published: July 2013

We examine whether herding among speculators in U.S. crude oil futures markets affects market prices and volatility. Using detailed data on the positions of hedge funds and swap dealers from 2005-2009, we find little evidence that herding destabilizes the crude oil futures market. To the contrary, herding among speculative traders is negatively correlated with contemporaneous volatility and does not lead next-day volatility. Our impulse-response analysis shows that market regulators should monitor herding since a shock to herding among all groups may lead to price changes, and, in the case of hedge funds, may lead to increased volatility. Interestingly, however, increased swap dealer herding actually dampens crude oil price volatility.
Measuring Index Investment in Commodity Futures Markets
Authors: Sanders Dwight R. , Irwin Scott H.
Published: July 2013

The “Masters Hypothesis” is the claim that unprecedented buyingpres-sure in recent years from new index investment created a massive bubble in commodity futures prices. Due to data limitations, some recent studies of the market impact of index investment in the WTI crude oil futures market impute index positions. We investigate the accuracy of the algorithm popularized by Masters (2008) to estimate index positions. The estimates generated by the Masters algorithm deviate substantially from the positions reported in the U.S. Commodity Futures Trading Commission’s (CFTC) Index Investment Data (IID) report—the agency’s best data on index positions. The Masters algorithm over-estimates the gross WTI crude oil position by an average of 142,000 contracts. Importantly, the deviation in the first half of 2008, the period of greatest concern about the market impact of index investment, is directionally wrong. These results suggest empirical tests of market impact based on mapping algorithms in WTI crude oil futures should be viewed with considerable caution.
Physical Markets, Paper Markets and the WTI-Brent Spread
Authors: Büyük şahin Bahattin , Lee Thomas K. , Moser James T. , Robe Michel A.
Published: July 2013

We document that, starting in the Fall of2008, the benchmark West Texas Intermediate (WTI) crude oil has periodically traded at unheard-of discounts to the corresponding Brent benchmark. We further document that this discount is not reflected in spreads between Brent and other benchmarks that are directly comparable to WTI. Drawing on extant models linking oil inventory conditions to the futures term structure, we test empirically several conjectures about how calendar and commodity spreads (nearby vs. first-deferred WTI; nearby Brent vs. WTI) should move over time and be related to storage conditions at Cushing. We then investigate whether, after controlling for macroeconomic and physical market fundamentals, spread behavior is partly predicted by the aggregate oil futures positions of commodity index traders.
The Oil Price-Macroeconomy Relationship Since the Mid-1980s: A Global Perspective
Authors: Morana Claudio
Published: July 2013

We investigate the oil price-macroeconomy relationship from a global perspective, by means of a large scale macro-financial-econometric model. In addition to real activity, we consider fiscal and monetary policy responses and labor and financial markets conditions, in order to provide a comprehensive account of the macro-financial effects of oil price shocks. We find that oil market supply side, speculative, preferences, and volatility shocks exercised recessionary effects during the first and second Persian Gulf War and 2008 oil price episodes. As long as oil supply will keep expanding at a slower pace than required by demand conditions, and in so far as the recently passed regulatory provisions aimed at controlling financial speculation in the oil (and other commodities) futures market will prove unsuccessful, a recessionary bias, determined by higher and more uncertain real oil prices, may then be expected to persist also in the near future.
Oil Price Uncertainty and Industrial Production
Authors: Pinno Karl , Serletis Apostolos
Published: July 2013

We estimate a bivariate GARCH-in-Mean VAR with a BEKK variance specification, to investigate whether oil price volatility affects real economic activity. We use the same data set of thirty seven, aggregate and disaggregate, industrial production indices used by Herrera et al. (2011) as a proxy for real output and a post-1973 data sample. We check the robustness of our results by using two proxies for the price of oil, the West Texas Intermediate (WTI) oil price and the Refiners’ Acquisition Cost (RAC) of crude oil, and by testing for both nominal and real effects. We find significant evidence of nonlinearities for both aggregate and disaggregate indices. Our research highlights the importance of nominal prices and extreme events such as the Great Recession in the transmission of nonlinearities. Our results show that nonlinear impacts of the price of oil on the aggregate economy vary according to time period even within the post-1974 data. Since 2000, oil price volatility is up markedly, but the number of industries it impacts is down when compared with the full sample. This is in keeping with what one would expect, based on trend improvements in GDP per unit of energy use. However, for those series, where oil price volatility is significant, the impact of oil volatility is substantially higher than in the full sample; this runs contrary to what one might expect from the observed GDP per unit of energy use improvements.
The 1 : 1 Adduct of 1,3-Diisopropyl-4,5-dimethyl-2,3-dihydroimidazol-2- ylidene and Nitrous Oxide
Authors: Göhner M. , Haiss P. , Kuhn N. , Ströbele M. , Zeller K.-P.
Published: July 2013

The nucleophilic carbene 1,3-diisopropyl-4,5-dimethyl-2,3-dihydroimidazol-2-ylidene (7) captures nitrous oxide under formation of both syn- (8) and anti-1,3-diisopropyl-4,5-imidazolium diazotate (9). The syn-isomer is the thermodynamically more stable form. As shown by X-ray crystallography, the two isomers are statistically distributed in the crystalline state
Activation of C–Cl Bonds: Synthesis and Structural Characterization of [Ru2(μ-Cl)(μ-PtBu2)(μ- Ph2PN(H)PPh2)(CO)4]
Authors: Mayer Tobias , Böttcher Hans-Christian
Published: July 2013

The synthesis and structural characterization of the complex [Ru2(μ-Cl)(μ-PtBu2)(μ-dppa)(CO)4] (4, dppa = Ph2PN(H)PPh2) are reported. The title compound and two other related complexes were obtained in high yields by the reaction of the coordinatively unsaturated species [Ru2(μ-H)(μ-PtBu2)(μ-PˆP)(CO)4] (PˆP = dppa, 3; PˆP =Ph2PN(Ph)PPh2, 5; PˆP =Ph2PN(CH2Ph)PPh2, 6) with carbon tetrachloride. Single crystals of 4 grown from dichloromethane-acetone have been analyzed by X-ray crystallography
Infinite Anionic Chains Formed by Alternating Bidentately Acting [SbS4]3- Anions and [Mn(dien)]2+ Complexes in the Compound [Mn(dien)2][Mn(dien)SbS4]2
Authors: Näther Christian , Herzberg Nicola , Bensch Wolfgang
Published: July 2013

The new compound [Mn(dien)2][Mn(dien)SbS4]2 (dien=diethylenetriamine) was synthesized under solvothermal conditions. It crystallizes in the non-centrosymmetric monoclinic space group P21 with a=7.5736(5), b=19.1081(16), c=13.1174(11) Å, b =90:022(9) , V =1898.3(3) Å3, and Z =2. The crystal structure is composed of one [Mn(dien)2]2+ cation and an anionic chain composed of [SbS4]3- anions and [Mn(dien)2]2+ cations. The [SbS4]3- anions connect [Mn(dien)2]2+ ions in a μ2-fashion to form an undulated {[Mn(dien)SbS4]}-2 chain running along [001]. The Mn2+ ions in the chain are in a rare distorted rectangular pyramidal coordination environment with 3 N and 1 S atom forming the base and one S atom being located at the apex of the pyramid. The anionic chains and the cations alternate along [010]. Several relatively strong intra- and inter-chain N-H-S bonding interactions are observed. From the Raman spectrum the reduction of the ideal Td symmetry of the [SbS4]3- anions is obvious because more resonances occur than expected for the undistorted geometry
A Dinuclear Palladium(II) Complex of the {N(SPPh2)2}- Ligand – Synthesis and Structure
Authors: Marks Sebastian , Roesky Peter W.
Published: July 2013

The synthesis and characterization including the crystal structure of the dinuclear palladium( II) complex [(k-S,S’)-{N(SPPh2)2}Pd(m-{k2-S'',S'''})-{N(SPPh2)2}PdCl2] (1) are reported. Compound 1 was obtained from the reaction of [PdCl2(COD)] (COD=1,5-cyclooctadiene) and HN(SPPh2)2 in a 1:1 molar ratio in CH2Cl2. The {N(SPPh2)2}- ligands act both as bridging and/or terminally chelating units
Synthesis of a 30-Membered Macrocycle Incorporating Two Ruthenium Sandwich Complexes
Authors: Schmid Alexander , Polborn Kurt , Lindel Thomas
Published: July 2013

The first macrocycle incorporating two ruthenium sandwich complexes has been synthesised. Key step is a cyclodimerisation by double etherification of a p-chlorophenylalanine-derived [RuCp*]+ complex. Silica-based cation exchange chromatography allowed the separation of dicationic diastereomers. Assignment of the relative configurations was possible by X-ray structure determination. Partial demetalation in acetonitrile proceeded in high yield by irradiation in the presence of biphenyl
A Base-stabilized Iodoborylene Complex of Platinum(II)
Authors: Braunschweig Holger , Brenner Peter B. , Dewhurst Rian D. , Radacki Krzysztof
Published: July 2013

The first base-stabilized iodoborylene platinum complex was prepared through the addition of 4-picoline (4-Pic) to a suspension of an iodo-bridged binuclear iodoboryl complex. An X-ray structure determination of the title compound has characterized the molecular structure as cis-[Pt{BI(4- Pic)}I2(PCy3)]. The bond lengths lie in the expected range for neutral, base-stabilized borylene complexes. The strong trans influence of the borylene moiety is reflected in the longer Pt-1 distance for the iodo ligand opposite the borylene, compared to that opposite the phosphine ligand
Cobalt(III)-Binding of Gluconate and 2-Amino-2-Deoxy-Gluconate
Authors: Pfister Max , Illi Sarah , Klüfers Peter
Published: July 2013

Two isomers of the [Co(tren)(D-Glc1A1,2H-2-K2O1,2)]+ (1) chelate are formed in equal parts in the reaction of [Co(tren)Cl2]Cl and sodium gluconate. In contrast, the gluconate’s 2-amino-2-deoxy derivative glucosaminate formed a single isomer of [Co(tren)(D-Glc1A2N1H-1-k2N,O2)]2+ (2). Crystals of the OC-6-34 isomer of 1, [1a]PF6 H2O, showed the support of the metal-binding site by intramolecular hydrogen bonds. Due to the inertness of the cobalt(III) chelates, spectroscopy on redissolved crystals of [1a]PF6 H2O allowed the separation of the two 13C NMR signal sets of the isomeric mixture. In a DFT approach, a small energy difference explained the formation of two isomers in the case of the gluconate. A larger difference was obtained for the glucosaminate, in line with the known rules for the stereospecific amino acid-Co(tren) chelation
Facile 1,1-Carboboration Reaction of a Diarylphosphino-substituted Conjugated Diyne with Tris(pentafluorophenyl)borane
Authors: Feldhaus Philipp , Kehr Gerald , Fröhlich Roland , Daniliuc Constantin G. , Erker Gerhard
Published: July 2013

Bis(dimesitylphosphanyl)butadiyne (14) reacts with B(C6F5)3 by a 1,1-carboboration sequence. The selective attack at a single phosphanyl-alkyne moiety is observed. First a phosphirenium-borate zwitterion 15 is formed at r. t. Thermolysis (80 °C) results in the E-selective formation of the 1,1- carboboration product, the frustrated Lewis pair (FLP) E-16, which upon heating to 160 °C eventually undergoes isomerization followed by an internal nucleophilic aromatic substitution reaction to give the product 17 featuring a -B(F)(C6F5)2 substituent at the five-membered P-heterocycle. Finally, the FLP E-16 was reacted with n-butylisocyanide to yield the five-membered heterocyclic product 18, formed by P,B addition to the isonitrile carbon atom. Compounds 14, 15, 17, and 18 were characterized by X-ray crystal structure analyses
Nickel(II) and Iron(II) Complexes with Tetradentate NHC/Amide Hybrid Ligands
Authors: Klawitter Iris , Meyer Steffen , Demeshko Serhiy , Meyer Franc
Published: July 2013

Two methylene-bridged bis(imidazolium) salts [H4L1](PF6)2 and [H4L2](PF6)2 with appended amide groups have been synthesized which, after deprotonation, may serve as potentially tetradentate ligands providing two bis(imidazole-2-ylidene) and two amide donors. Using [H4L1](PF6)2, a square-planar nickel(II) complex [NiL1] and a six-coordinate bis(ligand) iron(II) complex [Fe(HL1)2] have been isolated and structurally characterized. Their low-spin states have been confirmed spectroscopically, and their redox properties have been studied by cyclic voltammetry. Oxidations are metal-centered to give NiIII and FeIII species, respectively
Nutrição de mudas de Mimosa caesalpiniaefolia Benth. sob diferentes doses de N, P, K, Ca e Mg
Authors: Gonçalves Elzimar de Oliveira , Paiva Haroldo Nogueira de , Neves Júlio César de Lima , Gomes José Mauro
Published: July 2013

http://dx.doi.org/10.5902/198050989274Neste trabalho, objetivou-se verificar o teor e o conteúdo de N, P, K, Ca e Mg, em razão da aplicação de crescentes doses de fertilizantes e determinar o nível crítico desses nutrientes no solo e na planta, em mudas de sansão-do-campo (Mimosa caesalpiniaefolia Benth.) produzidas em três classes de solo (Argissolo Vermelho-Amarelo mesotrófico, Latossolo Vermelho-Amarelo álico e Latossolo Vermelho-Amarelo distrófico). As mudas foram plantadas em vasos com capacidade de 2,1 dm3. O experimento foi conduzido no período de dezembro de 2004 a abril de 2005, em Viçosa, MG. Os tratamentos foram delimitados segundo uma matriz baconiana, onde variou os macronutrientes em três doses diferentes e dois tratamentos adicionais (zero e base), com quatro repetições. As mudas de sansão-do-campo, em geral, apresentaram maior conteúdo dos nutrientes N, P, K, Ca e Mg à medida que a disponibilidade destes aumentava no solo. Tal fato refletiu em maiores teores dos nutrientes em todas as partes da planta. Entretanto, em alguns casos, não houve resposta em crescimento correspondente a esse aumento. Em termos de nível crítico, os valores que proporcionaram melhor crescimento da planta foram: N (16 a 17,3 g kg-1 na parte aérea), P (77 a 110 mg dm-³ no solo e 1 a 1,5 g kg-1 na parte aérea), K (51 a 86,5 mg dm-³ no solo e 5,7 a 7,1 g kg-1 na parte aérea), Ca (0,8 a 2,2 cmolc dm-³ no solo e 10 a 14,4 g kg-1 na parte aérea) e Mg (0,2 a 0,25 cmolc dm-³ no solo 1,3 a 2,4 g kg-1 na parte aérea). Contudo, para o K e o Ca, sugerem-se estudos com doses dentro dessa faixa de valores encontrados, para melhor definição do nível crítico. Dentre os solos estudados, os Latossolos se mostraram mais exigentes de adição de nutrientes, sobretudo para N e P, para uma adequada produção de mudas de Mimosa caesalpiniaefolia.
Crescimento e sobrevivência de mudas de sabiá (Mimosa caesalpiniaefolia Benth.) inoculadas com micro-organismos simbiontes em condições de campo
Authors: Mendes Marília Malta Cavalcante , Chaves Lúcia de Fátima de Carvalho , Pontes Neto Tarcísio Pio , Silva José Antônio Aleixo da , Figueiredo Márcia do Vale Barreto
Published: July 2013

http://dx.doi.org/10.5902/198050989277A Sabiá (Mimosa caesalpiniaefolia Benth.) possui a característica ecológica de se associar simbioticamente a bactérias fixadoras de Nitrogênio e fungos micorrízicos arbusculares. Tais associações são utilizadas como ferramentas biológicas capazes de minimizar o uso de fertilizantes químicos e beneficiar o desenvolvimento da planta em ambientes com déficit nutricional. Este trabalho teve como objetivo avaliar o crescimento da Sabiá em resposta à inoculação com rizóbio e fungos micorrízicos arbusculares, estabelecer curvas de crescimento em altura e diâmetro do colo, determinar os conteúdos de N e P na parte aérea das plantas e avaliar a sobrevivência das plantas em campo. A estirpe de rizóbio utilizada foi a BR3405, os fungos micorrízicos arbusculares utilizados foram Glomus clarum e Gigaspora margarita. A inoculação conjunta de Glomus clarum + Gigaspora margarita + BR3405 e a inoculação com o isolado Gigaspora margarita promoveram os melhores valores para as variáveis estudadas (altura, diâmetro do colo, conteúdo de N e P), sendo este último o tratamento mais indicado para o cultivo da Sabiá nas condições em estudo. As plantas apresentaram 100 % de sobrevivência, independente do tratamento utilizado. Não foi constatada diferença estatística para os conteúdos de N e P na parte aérea da Sabiá, porém, foi observado maior crescimento das plantas com o uso dos simbiontes.
Biomassa e nutrientes no corte raso de um povoamento de Pinus taeda L. de 27 anos de idade em Cambará do Sul – RS
Authors: Schumacher Mauro Valdir , Witschoreck Rudi , Calil Francine Neves , Lopes Vicente Guilheme
Published: July 2013

http://dx.doi.org/10.5902/198050989278Este trabalho, realizado em um povoamento de Pinus taeda de 27 anos de idade no município de Cambará do Sul (RS) teve como objetivos: estimar a produção de biomassa, o estoque de nutrientes e avaliar o impacto nutricional de diferentes intensidades de remoção de biomassa com a colheita florestal. A biomassa foi estimada por meio do ajuste de equações de regressão, com coleta de 15 árvores distribuídas em 5 classes diamétricas. O estoque de nutrientes foi obtido pelo produto entre o conteúdo médio de nutrientes em cada componente da biomassa e o número de árvores por classe diamétrica por hectare. A biomassa de Pinus taeda, acima do solo, foi estimada em 266,08 Mg ha-1, sendo composta por: 69,1 % de madeira do tronco, 17,1 % de galhos vivos, 6,7 % de casca do tronco, 3,8 % de galhos secos e 3,4 % de acículas. O estoque de nutrientes na biomassa, em kg ha-1, foi estimado em: 511,96 de N; 44,39 de P; 174,27 de K; 310,77 de Ca; 103,80 de Mg; 115,36 de S; 2,94 de B; 0,62 de Cu; 17,34 de Fe; 36,70 de Mn e 4,46 de Zn. A distribuição relativa do estoque total de nutrientes nos componentes da biomassa de Pinus taeda apresentou a seguinte sequência: madeira do tronco (43,6 %), galhos vivos (24,8 %), acículas (19,0 %), casca do tronco (8,7 %) e galhos secos (3,9 %). A colheita de toda biomassa acima do solo, quando comparada com a retirada apenas da madeira do tronco, acarreta uma elevação na exportação de nutrientes que pode variar de 58,0 % a 127,4 %, dependendo do nutriente, enquanto a remoção de biomassa aumentou 40,8 %.
A idade das plantações de Eucalyptus sp. influenciando os estoques de carbono
Authors: Wink Charlote , Reinert Dalvan José , Müller Ivanor , Reichert José Miguel , Jacomet Luciano
Published: July 2013

http://dx.doi.org/10.5902/198050989279O crescimento das árvores e acúmulo de biomassa, bem como a manutenção do resíduo florestal na superfície do solo pode atuar na retirada de carbono da atmosfera graças ao processo de ciclagem de material vegetal. O objetivo foi estudar a influência das plantações de Eucalyptus sp. com 20, 44 e 240 meses de idade sobre a variação de carbono no solo e na biomassa. O carbono no solo foi determinado em profundidade por meio de autoanalisador CHNS e o carbono na vegetação foi determinado pela biomassa em cada floresta, considerando um fator de 0,45 da massa seca. Determinaram-se a densidade e a análise granulométrica do solo. Para a comparação entre plantações, realizou-se a análise de variância e comparação de médias do carbono na vegetação e no solo, considerando o nível de 5 % de probabilidade. O teor e estoque de carbono no solo foram baixos, indicando ser uma característica natural da categoria dos Argissolos ou que o crescimento das florestas de eucalipto em substituição à vegetação campo nativo não agregou um aumento significativo no carbono, apesar de ter ocorrido um aumento significativo de carbono na biomassa acima do solo, a qual inclui a biomassa florestal aérea e a serapilheira. Portanto, apesar dos baixos valores de estoque de carbono, identificou-se um maior estoque médio total no solo quando comparado ao estoque acima do solo. Além disso, esse aumento acima do solo (compartimentos arbóreos e serapilheira) pode ser considerado significativo entre as plantações de eucalipto com diferentes idades.
Fenologia e morfologia de Diatenopteryx sorbifolia Radlk.
Authors: Felippi Marciele , Longhi Solon Jonas , Araujo Maristela Machado , Caron Braulio
Published: July 2013

http://dx.doi.org/10.5902/198050989280O presente estudo procurou elucidar a época de ocorrência de flores e frutos e os aspectos morfológicos externos e internos da flor, fruto e semente, e externos da plântula e da muda de Diatenopteryx sorbifolia Radlk (Sapindaceae). A coleta do material botânico e as observações fenológicas foram realizadas em árvores matrizes, localizadas em remanescentes, no Município de Frederico Westphalen, RS, entre março de 2007 a março de 2010. O trabalho foi conduzido no Laboratório de Sementes do Departamento de Ciências Florestais, Universidade Federal de Santa Maria, RS. A espécie floresceu de setembro a outubro. A frutificação anual ocorreu de novembro a janeiro, tendo dispersão anemocórica. Houve irregularidade na produção de frutos conforme os anos, não havendo sincronismo entre matrizes durante as fenofases. A espécie possui inflorescência do tipo tirso, pleiotirso, com pequenas flores de coloração branca, hermafroditas com ovário súpero, sincárpico, bicarpelar e uniovular, como também flores unissexuais masculinas. O fruto simples, seco e indeiscente, de coloração castanha, é do tipo esquisocarpáceo, constituído por dois samarídeos contendo de uma a duas sementes, de formato ovoide, coloração castanha, exalbuminosas, com embrião axial e cotilédones carnosos. O processo germinativo iniciou a partir do 2° dia após a semeadura, sendo a germinação do tipo epígea. Após 18 dias, a plântula fanerocotiledonar está formada. A muda, nas condições de estudo, está formada três meses após a semeadura. A caracterização fenológica, assim como a morfológica, se constitui informação relevante para a identificação da espécie a campo, coleta e análise de sementes, como também, a produção de mudas.
Crescimento e nutrição de erva-mate influenciados pela adubação nitrogenada, fosfatada e potássica
Authors: Santin Delmar , Benedetti Eliziane Luiza , Bastos Marília Camotti , Kaseker Jéssica Fernandes , Reissmann Carlos Bruno , Brondani Gilvano Ebling , Barros Nairam Félix de
Published: July 2013

http://dx.doi.org/10.5902/198050989282A ocorrência natural da erva-mate em solos ácidos e com baixa fertilidade natural, levou essa espécie a ser considerada de baixa exigência nutricional, principalmente em relação ao fósforo, embora pouco se conheça também sobre a exigência de N e K. Diante disto, o objetivo deste trabalho foi avaliar o crescimento, teor de nutrientes no solo e em plantas jovens de erva-mate submetidas a doses de P combinadas com NK. Aplicou-se 0, 100, 200, 400 e 600 mg dm-3 de P2O5 combinados com 0, 50 e 100 mg dm-3 de N e K2O a um Latossolo Vermelho distrófico. Três mudas de erva-mate foram transplantadas para vasos com 2,9 dm3 de solo. Aos 120 dias determinaram-se a altura, diâmetro do caule, comprimento e volume radicular e produção de matéria seca da parte aérea e radicular das mudas. Determinaram-se os teores de N, P, K, Ca, Mg, Fe, Cu, Zn, Mn e Al das folhas e raízes, além do conteúdo de N, P, K, Ca e Mg. Amostras de solo foram submetidas à análise química. O crescimento da erva-mate foi afetado pela interação entre P e NK, demonstrando melhor crescimento quando o teor de P no solo estava entre 18,5 a 28,6 mg dm-3 combinado com 100 mg dm-3 de N e K2O. Em doses superiores a 400 mg dm-3 de P2O5, as folhas passaram a apresentar clorose internerval, sintoma típico de deficiência de Fe. A ordem dos macronutrientes mais exigidos e que mais contribuíram para o crescimento da erva-mate foi P, N, K, Mg e Ca. A erva-mate cresce bem em solos com altos teores de P, mas depende da boa disponibilidade de N, K e Ca.
Dinâmica da estrutura da vegetação do sub-bosque sob influência da exploração em uma floresta de terra firme no município de Moju – PA
Authors: Mendes Fernanda da Silva , Jardim Fernando Cristóvam da Silva , Carvalho João Olegário Pereira de , Souza Deivison Venício , Araújo Clívia Bezerra , Oliveira Mariana Gomes de , Leal Eduardo da Silva
Published: July 2013

http://dx.doi.org/10.5902/198050989283Analisou-se a dinâmica da estrutura da vegetação do sub-bosque de uma floresta de terra firme sob a influência de clareiras durante 12 anos após a exploração florestal de impacto reduzido no município de Moju, Pará, na Amazônia Oriental, Brasil. Angiospermas de 10 cm de altura a 5 cm de DAP foram inventariadas em 468 m² de amostras, em seis ocasiões (1998, 1999, 2000, 2001, 2007 e 2010), analisadas de acordo com as formas de vida (árvores, arbustos, lianas, ervas e palmeiras), considerando a abundância, a frequência, as categorias de tamanho (CT1 = 10 cm ≤ HT < 50 cm; CT2 = 50 cm ≤ HT ≤130 cm; CT3 = 130 cm < HT e DAP < 2 cm; e CT4 = 2 cm ≤ DAP < 5 cm) e a regeneração natural relativa. As famílias mais representativas foram Burseraceae, Marantaceae, Violaceae e Lecythidaceae em todas as ocasiões, enquanto as espécies mais importantes foram Monotagma sp1., Monotagma sp2., Rinorea guianensis, Lecythis idatimon e Protium pilosum. As formas de vida mais representativas foram, em ordem decrescente, árvores, ervas e lianas em todas as ocasiões. A dinâmica das diferentes formas de vida foi dependente da intensidade de luz. As clareiras possibilitaram o estabelecimento de regeneração de espécies comerciais e potencialmente comerciais, indicando que essas espécies não necessitam de condução para garantir o estoque para futuros cortes.
Óleo essencial de eucalipto como bioestimulador do crescimento de fungos ectomicorrízicos in vitro
Authors: Steffen Ricardo Bemfica , Antoniolli Zaida Inês , Steffen Gerusa Pauli Kist , Jacques Rodrigo Josemar Seminoti , Santos Marcos Leandro dos , Godoy Helena Teixeira , Bogusz Júnior Stanislau
Published: July 2013

http://dx.doi.org/10.5902/198050989285Os metabólitos secundários extraídos de essências florestais conhecidamente micossimbiontes podem estimular o crescimento de isolados ectomicorrízicos in vitro. Assim, determinou-se o efeito de concentrações do óleo essencial de Eucalyptus grandis no estímulo ao crescimento dos fungos ectomicorrízicos Pisolithus sp. (UFSC Pt 24 e UFSC Pt 188), Pisolithus microcarpus (UFSC Pt 116), Chondrogaster angustiporus (UFSC Ch 163), Scleroderma citrinum (UFSC Sc 124) e Suillus sp. (UFSM RA 2.2 e UFSM RA 2.8) em meio de cultura líquido. Após o período de 25 dias de incubação, avaliou-se a morfologia e o crescimento dos isolados. A adição do óleo essencial nas concentrações de 20 a 30 μL L-1 promoveu crescimento miceliano in vitro nos isolados UFSC Pt 24, UFSC Pt 116, UFSC Ch 163, UFSC Sc 124, UFSM RA 2.2 e UFSM RA 2.8. A adição do óleo essencial na concentração de 20 μL L-1 resultou em aumento no diâmetro e na ramificação das hifas dos isolados UFSC Pt 116 e UFSC Pt 24. A utilização de óleo essencial na elaboração de meios de cultura para o crescimento de isolados ectomicorrízicos mostra-se eficiente, por aumentar a produção de massa micelial do fungo.
Solos e geoambientes do Parque Nacional do Viruá e entorno, Roraima: visão integrada da paisagem e serviço ambiental
Authors: Mendonça Bruno Araujo Furtado de , Fernandes Filho Elpídio Inácio , Schaefer Carlos Ernesto Gonçalves Reynaud , Simas Felipe Nogueira Bello , Vale Junior José Frutuoso do , Lisboa Beatriz de Aquino Ribeiro , Mendonça Júlia Gaio Furtado de
Published: July 2013

http://dx.doi.org/10.5902/198050989287O Parque Nacional (PARNA) do Viruá ocupa 227.011 ha, na região do baixo Rio Branco, Roraima. A região compreende um extenso mosaico de ambientes complexos inundáveis, florestais e não florestais. Este trabalho teve como objetivo geral detalhar os aspectos pedológicos e geoambientais do Parque e entorno, em uma visão integrada da paisagem e, além disso, estimar o estoque de carbono nos solos e geoambientes. Foram descritos e coletados 29 perfis de solos nas principais fitofisionomias de Campinaranas e Florestas do Parque e entorno. Destacaram-se os seguintes: Espodossolo Humilúvico, Neossolo Quartzarênico, Neossolo Flúvico, Neossolo Litólicos, Latossolo Vermelho-Amarelo, Latossolo Vermelho, Cambissolo Háplico, Cambissolo Flúvico, Gleissolo Háplico e Plintossolo Háplico. Os solos apresentaram distribuição espacial com limites abruptos e com forte associação entre as fitofisionomias. Foram agrupados em três pedoambientes: (1) solos arenosos das campinaranas, (2) solos associados aos inselbergs e adjacências e (3) solos aluviais. Foram mapeadas e descritas 18 unidades geoambientais no Parque e entorno. Os geoambientes predominantes no Parque foram: Planícies Arenosas e Paleodunas com Campinarana Graminosa e Arbustiva em Neossolos Quartzarênicos hidromórficos e Espodossolos; e Planícies de Inundação e Terraços com Floresta de Igapó sobre solos hidromórficos arenosos, com respectivamente 24,6 % e 20,1 % da área estudada. Em termos de estoque total de carbono nos solos, destacaram-se os geoambientes dos complexos arenosos das Campinaranas e associações, com 9450,9 Gg C. A grande extensão e representatividade dos complexos arenosos das Campinaranas fazem do PARNA Viruá uma Unidade de Conservação de proteção integral com forte vocação para preservação e conservação de sistemas arenícolas amazônicos. As áreas sob o domínio de Espodossolos possuem os maiores estoques de carbono orgânico e os complexos arenosos das Campinaranas e associações representam os geoambientes mais relevantes na prestação de serviços ambientais de conservação do carbono nos solos.
Efeito do estresse hídrico simulado com NaCl, manitol e PEG (6000) na germinação de sementes de Erythrina falcata Benth
Authors: Pelegrini Luciana Luiza , Borcioni Elis , Nogueira Antônio Carlos , Koehler Henrique Soares , Quoirin Marguerite Germaine Ghislaine
Published: July 2013

http://dx.doi.org/10.5902/198050989295A espécie Erythrina falcata Benth. (Fabaceae) é usada em sistemas agroflorestais, na restauração de florestas de mata ciliar, em locais sujeitos à inundação e na recuperação de ecossistemas degradados. O objetivo deste trabalho foi avaliar os possíveis efeitos do estresse hídrico na germinação de sementes de Erythrina falcata. O experimento foi realizado no Laboratório de Sementes Florestais da Universidade Federal do Paraná (UFPR) Paraná, Brasil. As unidades experimentais consistiram em caixas do tipo gerbox, contendo duas folhas de papel filtro e 25 sementes por caixa. Às folhas foi acrescido de 10 ml de cada solução osmótica. As caixas foram vedadas com parafilme e colocadas em câmaras de germinação do tipo Mangelsdorf, sob luz contínua à temperatura de 25±2 ºC. Testaram-se os seguintes potenciais osmóticos: 0.0; -0,2; -0,4; -0,6; -0,8 e -1,0 MPa para NaCl, manitol e PEG (6000). As sementes foram transferidas a cada dois dias para os mesmos potenciais osmóticos. A menor tolerância ao estresse hídrico foi observada simulando-o com PEG 6000. O limite para germinação está entre -0,2 e -0,4 MPa de PEG, enquanto que os potenciais osmóticos testados com NaCl e manitol não influenciaram o processo germinativo.
Concise Review: The Involvement ofSOX2in Direct Reprogramming of Induced Neural Stem/Precursor Cells
Authors: Maucksch Christof , Jones Kathryn S. , Connor Bronwen
Published: July 2013

Since induced pluripotent stem cells were first generated from mouse embryonic fibroblasts in 2006, somatic cell reprogramming has become a powerful and valuable tool in many fields of biomedical research, with the potential to lead to the development of in vitro disease models, cell-based drug screening platforms, and ultimately novel cell therapies. Recent research has now demonstrated the direct conversion of fibroblasts into stem, precursor, or mature cell types that are committed in their fate within a specific lineage, such as hematopoietic precursors or mature neurons. This has been achieved by ectopic expression of defined, tissue-specific transcription factors. Several studies have demonstrated direct reprogramming of mouse and human fibroblasts into immature neural stem or precursor cells, either by transient expression of the four pluripotency genes OCT3/4, KLF4, SOX2, and C-MYC or by application of different combinations of up to 11 neural transcription factors. Interestingly, in all of these studies SOX2 was introduced alone or in combination with other transcription factors. In this review we discuss the different combinations of ectopic transcription factors used to generate neural stem/precursor cells from somatic cells, with particular emphasis on SOX2 and its potential to act as a master regulator for reprogramming to a neural precursor state.
Balancing Industrial Concentration and Competition for Economic Development in Asia: Insights from South Korea, China, India, Indonesia and the Philippines
Authors: Mendoza Ronald Umali , Barcenas Lai-Lynn Angelica , Mahurkar Padmini
Published: July 2013

In pursuit of economic growth and development, countries have tried to strike a balance between competition and industrial policies across time. This paper will review the empirical evidence on industrial concentration and its economic correlates (notably firms' performance as measured by profitability, factor productivity and innovation). It will also analyze how the introduction of competition policies and laws in South Korea, China, India, Indonesia and the Philippines affected industrial concentration. It will examine at what point in their industrialization and economic development these economies implemented these laws and policies. The empirical literature suggests that industrial concentration could exhibit an inverted-U-shaped relationship as far as its link to certain economic indicators of success, such as productivity and innovation. This suggests a role for recalibrating policies to adjust the balance between industrial concentration and competition, so that the over-all outcomes are net welfare enhancing. Indeed, country policy experiences reviewed here appear to demonstrate this recalibration, notably following privatization and liberalization policies.