bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toxicity of citrus essential oils against Ceratitis capitata (Diptera: Tephritidae) larvae
Authors: Papachristos D.P. , Kimbaris A.C. , Papadopoulos N.T. , Polissiou M.G. 
Published: September 2009

AbstractCitrus peel essential oils are considered to constitute the most important resistance factor of citrus fruits against fruit flies. Essential oils were obtained from three sweet orange varieties, one bitter orange and one lemon variety. Yield, chemical composition and toxicity against neonates of the Mediterranean fruit fly were determined. Based on chemical analysis, the toxicity of commercially purchased major and minor components (monoterpenes and sesquiterpenes) of essential oils was determined. In addition, fractions were prepared to evaluate the role of minor components in the toxicity of crude essential oils. Limonene was by far the most abundant ingredient (96.2–97.4%) in all sweet orange varieties and in bitter orange, while the concentration of limonene was much lower in lemon essential oils (74.3%). Orange and bitter orange essential oils were more toxic than lemon essential oils. The toxicity of orange and bitter orange essential oils was similar to that of their major component limonene. In tests of commercially purchased chemicals, the oxygenated components of essential oils were more toxic than hydrocarbons but their low concentration in citrus essential oils could not affect the toxic activity of essential oils. The presence of α‐pinene and β‐pinene seems to account for the lower toxicity of lemon essential oils in relation to other citrus essential oils. The importance of understanding the toxicity of essential oils in relation to their composition and their role regarding the resistance of citrus fruits to Ceratitis capitata infestation is discussed.
150 Years of Tree Establishment, Land Use and Climate Change in Montane Grasslands, Northwest Argentina
Authors: Carilla Julieta , Grau H. Ricardo 
Published: September 2009

ABSTRACTDegraded grasslands resulting from intensive land use appear to be highly resistant to tree invasion due to interactions between land use, climate, grazing and fire. We describe long‐term patterns of tropical montane forest regeneration into degraded grasslands and analyze their relationships with historical changes in rainfall, grazing and fire in Los Toldos valley (Northwest Argentina), cloud forest life zone (1600 m asl). We used dendrochronological techniques to reconstruct spatial and temporal patterns of Podocarpus parlatorei establishment (the dominant tree species in secondary forests) and grassland fires for the last 150 yr. We assessed current livestock spatial distribution along the valley through feces sampling. Inferred tree establishment patterns (i.e., considering age structure and mortality) were analyzed in relation to temporal and spatial patterns of grazing and fire derived from our own analyses and from government statistics, and to rainfall patterns derived from previous dendrochronological reconstructions. Current grazing intensity was higher close to the local township. Fire occurrence increased with periods of above‐average rainfall (higher fuel productivity), and tended to increase with distance to township (less grazing). Tree establishment in grasslands was spatially associated with high grazing intensity and low fire frequency, and temporally associated with periods of high grazing intensity and below‐average rainfall. Despite climatic and land‐use changes leading to conditions potentially favorable for trees (i.e., more rainfall, less grazing), grasslands persist in this study area, likely due to the direct (saplings burning) and indirect (soil degradation and desiccation) effects of recurrent fires, enhanced by decreasing grazing and increasing rainfall.
The influence of the C+N+O abundances on the determination of the relative ages of globular clusters: the case of NGC1851 and NGC6121 (M4)
Authors: D'Antona F. , Stetson P. B. , Ventura P. , Milone A. P. , Piotto G. , Caloi V. 
Published: September 2009

Abstract
The colour–magnitude diagram (CMD) of NGC 1851 presents two subgiant branches (SGBs), probably due to the presence of two populations differing in total C+N+O (carbon+nitrogen+oxygen) content. We test the idea that a difference in total C+N+O may simulate an age difference when comparing the CMD of clusters to derive relative ages. We compare NGC 1851 with NGC 6121 (M4), a cluster of very similar [Fe/H]. We find that, with a suitable shift of the CMDs that brings the two red horizontal branches at the same magnitude level, the unevolved main sequence and red giant branch match, but the SGB of NGC 6121 and its red giant branch ‘bump’ are fainter than in NGC 1851. In particular, the SGB of NGC 6121 is even slightly fainter than the faint SGB in NGC 1851. Both these features can be explained if the total C+N+O in NGC 6121 is larger than that in NGC 1851, even if the two clusters are coeval. We conclude by warning that different initial C+N+O abundances between two clusters, otherwise similar in metallicity and age, may lead to differences in the turnoff morphology that can be easily attributed to an age difference.
A Case Study of the Mechanics of Extratropical Influence on the Initiation of the Madden–Julian Oscillation
Authors: Ray Pallav , Zhang Chidong 
Published: September 2009

Abstract
Mechanisms for extratropical influences on the initiation of the Madden–Julian oscillation (MJO) are investigated using numerical simulations and a global reanalysis product. Previous simulations by a tropical channel model captured the timing and gross features of the initiations of two MJO events and suggested that the initiations were due to influences from the extratropics. In this study, latitudinal transport of momentum from the extratropics is found to be crucial in generating the lower tropospheric westerlies in the tropics associated with the MJO initiation. The diagnoses of the zonal momentum budget for the MJO initiation region revealed that the advection by meridional winds could be important prior to the initiation of the MJO. The time evolution of the wave activity identifies its source over the southern Indian Ocean where it grows by extracting kinetic energy from the mean flow. The time scale of the lateral boundary conditions that is responsible for the MJO initiation is also investigated. The implications of the results and limitations of the approach are discussed.
Finite-Amplitude Equilibration of Baroclinic Waves on a Jet
Authors: Lee Sukyoung 
Published: September 2009

Abstract
A two-layer quasigeostrophic model is used to study the equilibration of baroclinic waves. In this model, if the background flow is relaxed toward a jetlike profile, a finite-amplitude baroclinic wave solution can be realized in both supercritical and subcritical regions of the model’s parameter space. Analyses of the model equations and numerical model calculations indicate that the finite-amplitude wave equilibration hinges on the breaking of Rossby waves before they reach their critical latitude. This “jetward” wave breaking results in an increase in the upper-layer wave generation and a reduction in the vertical phase tilt. This change in the phase tilt has a substantial impact on the Ekman pumping, as it weakens the damping on the lower-layer wave for some parameter settings and enables the Ekman pumping to serve as a source of wave growth at other settings. Together, these processes can account for the O(1)-amplitude wave equilibration.
From a potential vorticity (PV) perspective, the wave breaking reduces the meridional scale of the upper-layer eddy PV flux, which destabilizes the mean flow. This is followed by a strengthening of the lower-layer eddy PV flux, which weakens the lower-layer PV gradient and constrains the growth of the lower-layer eddy PV. The same jetward wave breaking focuses the upper-layer PV flux toward the jet center where the upper-layer PV gradient is greatest. This results in an intensification of the upper-layer eddy PV relative to lower-layer eddy PV. Because of this large ratio, the upper-layer eddy PV plays the primary role in inducing the upper- and lower-layer eddy streamfunction fields, decreasing the vertical phase tilt. As a result, the Ekman pumping on the eddies is weakened, and for some parameter settings the Ekman pumping can even act as a wave source, contributing toward O(1)-amplitude wave equilibration. By reducing the horizontal shear of the zonal wind, the same wave breaking process weakens the barotropic decay, which also contributes to the wave amplification.
Submonthly Indian Ocean Cooling Events and Their Interaction with Large-Scale Conditions
Authors: Lloyd Ian D. , Vecchi Gabriel A. 
Published: September 2009

Abstract
The Indian Ocean exhibits strong variability on a number of time scales, including prominent intraseasonal variations in both the atmosphere and ocean. Of particular interest is the south tropical Indian Ocean thermocline ridge, a region located between 12° and 5°S, which exhibits prominent variability in sea surface temperature (SST) due to dominant winds that raise the thermocline and shoal the mixed layer. In this paper, submonthly (less than 30 day) cooling events in the thermocline ridge region are diagnosed with observations and models, and are related to large-scale conditions in the Indo-Pacific region. Observations from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) satellite were used to identify 16 cooling events in the period 1998–2007, which on average cannot be fully accounted for by air–sea enthalpy fluxes. Analysis of observations and a hierarchy of models, including two coupled global climate models (GFDL CM2.1 and GFDL CM2.4), indicates that ocean dynamical changes are important to the cooling events. For extreme cooling events (above 2.5 standard deviations), air–sea enthalpy fluxes account for approximately 50% of the SST signature, and oceanic processes cannot in general be neglected. For weaker cooling events (1.5–2.5 standard deviations), air–sea enthalpy fluxes account for a larger fraction of the SST signature. Furthermore, it is found that cooling events are preconditioned by large-scale, low-frequency changes in the coupled ocean–atmosphere system. When the thermocline is unusually shallow in the thermocline ridge region, cooling events are more likely to occur and are stronger; these large-scale conditions are more (less) likely during La Niña (El Niño/Indian Ocean dipole) events. Strong cooling events are associated with changes in atmospheric convection, which resemble the Madden–Julian oscillation, in both observations and the models.
Geographic Aspects of Temperature and Concentration Feedbacks in the Carbon Budget
Authors: Boer G. J. , Arora V. 
Published: September 2009

Abstract
The geographical distribution of feedback processes in the carbon budget is investigated in a manner that parallels that for climate feedback/sensitivity in the energy budget. Simulations for a range of emission scenarios, made with the Canadian Centre for Climate Modelling and Analysis (CCCma) earth system model (CanESM1), are the basis of the analysis. Anthropogenic CO2 emissions are concentrated in the Northern Hemisphere and provide the forcing for changes to the atmospheric carbon budget. Transports redistribute the emitted CO2 globally where local feedback processes act to enhance (positive feedback) or suppress (negative feedback) local CO2 amounts in response to changes in CO2 concentration and temperature.
An increased uptake of CO2 by the land and ocean acts to counteract increased atmospheric CO2 concentrations so that “carbon–concentration” feedbacks are broadly negative over the twenty-first century. Largest values are found over land and particularly in tropical regions where CO2 acts to fertilize plant growth. Extratropical land also takes up CO2 but here the effect is limited by cooler temperatures. Oceans play a lesser negative feedback role with comparatively weak uptake associated with an increase in the atmosphere–ocean CO2 gradient rather than with oceanic biological activity.
The effect of CO2-induced temperature increase is, by contrast, to increase atmospheric CO2 on average and so represents an overall positive “carbon–temperature” feedback. Although the average is positive, local regions of both positive and negative carbon–temperature feedback are seen over land as a consequence of the competition between changes in biological productivity and respiration. Positive carbon–temperature feedback is found over most tropical land while mid–high-latitude land exhibits negative feedback. There are also regions of positive and negative oceanic carbon–temperature feedback in the eastern tropical Pacific.
The geographical patterns of carbon–concentration and carbon–temperature feedbacks are comparatively robust across the range of emission scenarios used, although their magnitudes are somewhat less robust and scale nonlinearly as a consequence of the large CO2 concentration changes engendered by the scenarios. The feedback patterns deduced nevertheless serve to illustrate the localized carbon feedback processes in the climate system.
Application of the Priestley–Taylor Approach in a Two-Source Surface Energy Balance Model
Authors: Agam Nurit , Kustas William P. , Anderson Martha C. , Norman John M. , Colaizzi Paul D. , Howell Terry A. , Prueger John H. , Meyers Tilden P. , Wilson Tim B. 
Published: September 2009

Abstract
The Priestley–Taylor (PT) approximation for computing evapotranspiration was initially developed for conditions of a horizontally uniform saturated surface sufficiently extended to obviate any significant advection of energy. Nevertheless, the PT approach has been effectively implemented within the framework of a thermal-based two-source model (TSM) of the surface energy balance, yielding reasonable latent heat flux estimates over a range in vegetative cover and climate conditions. In the TSM, however, the PT approach is applied only to the canopy component of the latent heat flux, which may behave more conservatively than the bulk (soil + canopy) system. The objective of this research is to investigate the response of the canopy and bulk PT parameters to varying leaf area index (LAI) and vapor pressure deficit (VPD) in both natural and agricultural vegetated systems, to better understand the utility and limitations of this approximation within the context of the TSM. Micrometeorological flux measurements collected at multiple sites under a wide range of atmospheric conditions were used to implement an optimization scheme, assessing the value of the PT parameter for best performance of the TSM. Overall, the findings suggest that within the context of the TSM, the optimal canopy PT coefficient for agricultural crops appears to have a fairly conservative value of ∼1.2 except when under very high vapor pressure deficit (VPD) conditions, when its value increases. For natural vegetation (primarily grasslands), the optimal canopy PT coefficient assumed lower values on average (∼0.9) and dropped even further at high values of VPD. This analysis provides some insight as to why the PT approach, initially developed for regional estimates of potential evapotranspiration, can be used successfully in the TSM scheme to yield reliable heat flux estimates over a variety of land cover types.
Idealized Two-Dimensional Modeling of a Coastal Buoyancy Front, or River Plume, under Downwelling-Favorable Wind Forcing with Application to the Alaska Coastal Current
Authors: Williams William J. , Weingartner Thomas J. , Hermann Albert J. 
Published: September 2009

AbstractThe cross-shelf structure of a buoyancy-driven coastal current, such as produced by a river plume, is modeled in a two-dimensional cross-shelf slice as a “wide” geostrophically balanced buoyancy front. Downwelling-favorable wind stress applied to this front leads to advection in the surface and bottom boundary layers that causes the front to become steeper so that it eventually reaches a steep quasi-steady state. This final state is either convecting, stable and steady, or stable and oscillatory depending on D/δ* and by /f 2, where D is bottom depth, δ* is an Ekman depth, by is the cross-shelf buoyancy gradient, and f is the Coriolis parameter. Descriptions of the cross-shelf circulation patterns are given and a scaling is presented for the isopycnal slope. The results potentially apply to the Alaska Coastal Current, which experiences strong, persistent downwelling-favorable wind stress during winter, but also likely have application to river plumes subjected to downwelling-favorable wind stress.
Airborne Doppler Lidar Investigation of Sea Surface Reflectance at a 355-nm Ultraviolet Wavelength
Authors: Li Zhigang , Lemmerz Christian , Paffrath Ulrike , Reitebuch Oliver , Witschas Benjamin 
Published: September 2009

Abstract
The analysis of the sea surface reflectance for different incidence angles based on observations of an airborne Doppler lidar at an ultraviolet wavelength of 355 nm is described. The results were compared to sea surface reflectance models, including the contribution from whitecaps, specular reflection, and the subsurface volume backscattering. The observations show the expected effect of the wind stress on the sea surface reflectance and allow new insights into the significant contribution from subsurface reflectance for large incidence angles. While most of the observations and model results were obtained for isotropic reflectance, first results on anisotropic reflectance are also provided. The results from this study are relevant to future spaceborne wind lidar instruments, for example, the Atmospheric Dynamics Mission (ADM)-Aeolus, which could use the sea surface reflectance for the calibration of intensity and wind.
Synthesis of 4H-Cyclopenta[def]phenanthrene from 1-Naphthylacetic Acid
Authors: Kim Jinwoo , Jin Youngeup , Song Suhee , Kim Il , Suh Hongsuk 
Published: September 2009

Abstract
4H-cyclopenta[def]phenanthrene (CPP) was prepared from 1-naphthylacetic acid in six steps with an overall yield of 36%. From easily available ethyl 1-naphthaleneacetate, the Michael addition and Lewis acid catalyzed dicyclization provided the diketone, which was reduced and dehydrated to give CPP.
Ni–Al Layered Double Hydroxide Prepared by Liquid Phase Deposition
Authors: Mizuhata Minoru , Hosokawa Akinobu , Béléké Alexis Bienvenu , Deki Shigehito 
Published: September 2009

Abstract
Al-containing nickel layered double hydroxide was prepared by liquid phase deposition (LPD) using aluminum metal or compounds as the fluorine scavenger in the equilibrium reaction of nickel–fluorine complex ion. The obtained phases depend on the Al content when it is solely used as F− scavenger; α-nickel hydroxide is the predominant phase and a small amount of β-phase is detected. In contrast pure Ni–Al LDH/C composites, isostructural and isomorphic to α-Ni(OH)2 are obtained at any range of Al content from 0 to ca. 30 mol % of [Al]⁄[Al+Ni]. High stability of LDH in 6 M aqueous KOH solution was performed because of low impurity of cation species.
Reductive Self-coupling Reaction of Imines and Aldehydes Induced by Strontium Metal
Authors: Miyoshi Norikazu , Kohno Tadashi , Wada Makoto , Matsunaga Sei , Mizota Isao , Shimizu Makoto 
Published: September 2009

Abstract
Aromatic aldimines reacted with Sr in the presence of a catalytic amount of iodine to give self-coupling products in good yields, whereas aromatic and aliphatic aldehydes underwent a similar reaction effected by the combined use of Sr and Al(OEt)3.
Synthesis of Polysilanes by Tunneling Reactions of H Atoms with Solid Si2H6 at 10 K
Authors: Sogoshi Norihito , Sato Shoji , Takashima Hideaki , Sato Tetsuya , Hiraoka Kenzo 
Published: September 2009

Abstract
Tunneling reactions of H atoms with solid Si2H6 at 10 K were investigated. The in situ and real-time reactions H + Si2H6 to form silane and polysilanes were monitored using FT-IR. Quantitative analysis of gaseous products was made by thermal desorption spectrometry. Monosilane and polysilanes were detected as major reaction products. The intermediate product SiH2 was suggested to play an important role for the growth of the Si–Si network of the solid products.
Applications of Emission Spectroscopy to Trace Element Analysis in Plant and Soil Samples
Authors: Schrenk WG 
Published: September 2009

This paper describes spectrographic procedures which have been of use in agricultural research. Included has been a discussion of the approach used to design satisfactory analytical procedures and a description of some of the problems in which these methods have been used.
The use of spectrographic techniques in agriculture is not new, neither is it limited in scope. In fact, this approach is used all over the world where problems of this nature are studied. It is regretted that all such work cannot be acknowledged in a paper such as this. As the field of analytical spectroscopy continues to grow and develop, it may be expected that workers in agriculture will continue to take advantage of the methods of spectroscopy to help solve problems that would be extremely difficult, if not impossible, to study by other methods.
ASTM Investigation of Low-Temperature Viscometry of Engine Oils
Authors: Selby Theodore W. 
Published: September 2009

This paper constitutes a report by the chairman of Section B, Research Division VII on Flow Properties of ASTM Committee D-2 on Petroleum Products and Lubricants, on the activities of Section B in the field of engine oil viscometry at low temperatures.
In presenting this report, the chairman presumes to summarize the information thus far presented, privately or publicly, by members or associates of Section B. While this report may not completely reflect the views of all contributors, it is hoped that it correctly amalgamates their work into an easily accessible, and generally useful, body of information on the subject.
The members and associates of Section B contributing to the work in the area of high-shear viscometry of engine oils at low temperatures are: O. L. Brandes, Member, of the Gulf Research and Development Co., A. W. Sisko, Associate, who contributed to the effort through L. C. Brunstrum, Member, both of the Standard Oil Co. of Indiana, G. A. Kohl and R. D. Skoglund, Associates, who contributed their work through J. R. Callaway, Member, all of the Texaco Research Laboratories, E. O. Forster, Associate, who contributed a portion of the total effort submitted by H. H. Horowitz, Member, both of the Esso Research and Engineering Co., E. W. Merrill, Member, of the Massachusetts Institute of Technology, M. J. Pohorilla, Member, of the Kendall Refining Co., and T. W. Selby, Member, of the General Motors Research Laboratories.
Comparison of In-Reactor Creep and Postirradiation Creep Tests of Structural Materials for Nuclear Applications
Authors: Gilbert E. R. , Harding N. E. 
Published: September 2009

Neutron irradiation can cause the creep rate of a material to increase, decrease, or to remain unchanged. Each of these possible results has been observed in creep during neutron irradiation. In hep alloys increased creep rates have been observed both in Zircaloy-2 and Zr-2.5Nb at creep rates below 10-10 sec-1 at 300 C. At temperatures above 350 C in-reactor creep rates of Zr-2.5Nb are no different from those of unirradiated control tests, whereas in Zircaloy-2 the creep rate may increase, decrease, or remain the same on reactor shutdown, depending on the stress and temperature. Stress relaxation tests reported for zirconium alloys below 100 C resulted in more relaxation during neutron irradiation, suggesting faster creep rates.
In-reactor creep tests for fcc alloys Type 304 stainless steel and Hastelloy X-280 at temperatures above 500 C have resulted in little if any difference in creep rate, although the range of second-stage creep was significantly reduced. Faster in-reactor creep rates are inferred for nickel, copper, and 18-8 stainless steel through greater stress relaxation during neutron irradiation below 100 C.