bluuebunny/crossref_metadata_2025 huggingface dataset:
Time variations of descent in the Antarctic vortex during the early winter of 1997
Authors: Kawamoto Nozomi , Kanzawa Hiroshi , Shiotani Masato
Published: September 2004

We analyzed long‐lived chemical constituents observed by the Improved Limb Atmospheric Spectrometer (ILAS) on board the Advanced Earth Observing Satellite (ADEOS) to study the stratospheric descent in the Southern Hemisphere polar vortex. The ILAS N2O distribution inside the polar vortex exhibited clear downward motion in February to June 1997. Average descent for the 5 months is estimated to be ∼2.1–1.7 km month−1 in the middle stratosphere. In late April to June when planetary waves are relatively active, the vertical velocity displays time variations with a period of about 10 days. These time variations also synchronize with both time variations of the temperature time change (∂/∂t) and the Eliassen‐Palm flux divergence (DF) in high latitudes. Moreover, a correlation coefficient map in the latitude‐height cross section between the vertical velocity and the temperature time change reveals an interesting four‐box pattern, suggesting warming below 10 hPa and cooling above 10 hPa in the polar region (70°–90°S) and an opposite distribution in midlatitudes (40°–70°S), when large descent is observed inside the polar vortex. It is just like the meridional circulation in response to DF induced by planetary waves, which was first illustrated by Matsuno's stratospheric sudden warming theory.
Entrainment process of carbon dioxide in the atmospheric boundary layer
Authors: de Arellano Jordi Vilà‐Guerau , Gioli Beniamino , Miglietta Franco , Jonker Harm J. J. , Baltink Henk Klein , Hutjes Ronald W. A. , Holtslag Albert A. M.
Published: September 2004

Aircraft and surface measurements of turbulent thermodynamic variables and carbon dioxide (CO2) were taken above a grassland in a convective atmospheric boundary layer. The observations were analyzed to assess the importance of the entrainment process for the distribution and evolution of carbon dioxide in the boundary layer. From the observations we were able to estimate the vertical profiles of the fluxes, the correlation coefficients, and the skewness of the virtual potential temperature, the specific humidity, and the carbon dioxide. These profiles indicate that important entrainment events occurred during the observed period. The data were also used to estimate the budgets for heat, moisture, and carbon dioxide. By studying this observational data we find that the entrainment of air parcels containing lower concentrations of water vapor and carbon dioxide significantly dries and dilutes the concentration of these two constituents in the boundary layer. This process is particularly important in the morning hours which are characterized by a rapidly growing boundary layer. The observations show that the CO2 concentration in the boundary layer is reduced much more effectively by the ventilation with entrained air than by CO2 uptake by the vegetation. We quantify this effect by calculating the ratio of the entrainment flux of CO2 to the surface flux of CO2(βc = −()e/()o). A value of βc equal to 2.9 is estimated at around 1300 UTC from the vertical profile of the carbon dioxide flux. We corroborate this observational evidence by reproducing the observed situation using a mixed layer model. The mixed layer model also yields the variation in time of βc. During the morning the ventilation process is more important than the CO2 uptake by the vegetation (βc > 1), whereas in the afternoon the assimilation by grass at the surface becomes the dominant process (βc < 1). This research points out the relevance of the entrainment process on the budget of carbon dioxide in the lower troposphere and the relevance of boundary layer dynamics in controlling the diurnal variation of carbon dioxide.
Exchange processes of volatile organic compounds above a tropical rain forest: Implications for modeling tropospheric chemistry above dense vegetation
Authors: Karl Thomas , Potosnak Mark , Guenther Alex , Clark Deborah , Walker John , Herrick Jeffrey D. , Geron Chris
Published: September 2004

Disjunct eddy covariance in conjunction with continuous in‐canopy gradient measurements allowed for the first time to quantify the fine‐scale source and sink distribution of some of the most abundant biogenic (isoprene, monoterpenes, methanol, acetaldehyde, and acetone) and photooxidized (MVK+MAC, acetone, acetaldehyde, acetic, and formic acid) VOCs in an old growth tropical rain forest. Our measurements revealed substantial isoprene emissions (up to 2.50 mg m−2 h−1) and light‐dependent monoterpene emissions (up to 0.33 mg m−2 h−1) at the peak of the dry season (April and May 2003). Oxygenated species such as methanol, acetone, and acetaldehyde were typically emitted during daytime with net fluxes up to 0.50, 0.36, and 0.20 mg m−2 h−1, respectively. When generalized for tropical rain forests, these fluxes would add up to a total emission of 36, 16, 19, 106, and 7.2 Tg/yr for methanol, acetaldehyde, acetone, isoprene, and monoterpenes, respectively. During nighttime we observed strong sinks for oxygenated and nitrogen‐containing compounds such as methanol, acetone, acetaldehyde, MVK+MAC, and acetonitrile with deposition velocities close to the aerodynamic limit. This suggests that the canopy resistance (Rc) is very small and not the rate‐limiting step for the nighttime deposition of many VOCs. Our measured mean dry deposition velocities of methanol, acetone, acetaldehyde, MVK+MAC, and acetonitrile were a factor 10–20 higher than estimated from traditional deposition models. If our measurements are generalized, this could have important implications for the redistribution of VOCs in atmospheric chemistry models. Our observations indicate that the current understanding of reactive carbon exchange can only be seen as a first‐order approximation.
A modeling study of the effect of nitric acid on cloud properties
Authors: Xue Huiwen , Feingold Graham
Published: September 2004

The effect of nitric acid (HNO3) on cloud microphysical and radiative properties is studied using an adiabatic cloud parcel model for a range of aerosol size distributions, different water vapor mass accommodation coefficients, and HNO3 concentrations. Results show that HNO3 not only increases cloud drop number concentration Nd, but also leads to significantly broader droplet size spectra at both the small‐ and large‐size ends. The broader spectra are generally the result of competition for H2O and HNO3 among the polydisperse droplets. The increase in the number of activated cloud droplets in the presence of HNO3, and the deactivation of some of the small cloud droplets due to the outgasing of HNO3, lead to spectral broadening at the small‐size end. At the large‐size end the broadening is caused by an increase in the driving force for growth. For small drops the driving force tends to be decreased by the presence of HNO3. Although Nd increases with increasing HNO3 concentration, the increases in cloud optical depth and albedo due to HNO3 cannot necessarily be predicted by the commonly used relationships for cloud optical properties. The dependence of the cloud optical depth on Nd to the one‐third power is shown to be an overestimate because droplet spectra are significantly broadened by HNO3. We show that broadening effects due to HNO3 and other chemical or microphysical factors need to be considered when estimating cloud optical properties and their effect on climate.
Does the Moon possess a molten core? Probing the deep lunar interior using results from LLR and Lunar Prospector
Authors: Khan A. , Mosegaard K. , Williams J. G. , Lognonné P.
Published: September 2004

It is the main purpose of this study to examine the deeper structure of the Moon in the light of four numbers. These are lunar mass M, mean moment of inertia I, second degree tidal Love number k2, and the quality factor Q, accounting for tidal dissipation within the solid body of the Moon. The former two have been measured by Lunar Prospector to high precision, and more than 30 years of lunar laser ranging (LLR) data have led to an estimate of the second degree tidal Love number and quality factor. The inverse problem dealt with here of obtaining information on the lunar density and S wave velocity profile from the four numbers follows our earlier investigations by employing an inverse Monte Carlo sampling method. We present a novel way of analyzing the outcome using the Bayes factor. The advantage lies in the fact that rather than just looking at a subset of sampled models, we investigate all the information sampled in different runs, i.e., take into account all samples, in order to estimate their relative plausibility. The most likely outcome of our study, based on the data, their uncertainties, and prior information, is a central core with a most probable S wave velocity close to 0 km/s, density of ∼7.2 g/cm3 and radius of about 350 km. This is interpreted as implying the presence of a molten or partially molten Fe core, in line with evidence presented earlier using LLR regarding the dissipation within the Moon.
Identification with Academics and Violence in Schools
Authors: Osborne Jason W.
Published: September 2004

The goal of this article is to present a theoretical model integrating identification with academics, motivation and engagement behaviors, academic outcomes, and violent or deviant behavior. Four different scenarios are presented in which students might be prone to engage in violent or undesirable behavior as a consequence of low or maladaptively high levels of identification with academics. The types of violent behavior likely to result from each scenario are discussed. Because domain identification has been shown to be malleable, this theoretical perspective leads directly to specific actions that might reduce the probability of undesirable behavior, and these actions are discussed.
Academic Socialization: Understanding Parental Influences on Children's School-Related Development in the Early Years
Authors: Taylor Lorraine C. , Clayton Jennifer D. , Rowley Stephanie J.
Published: September 2004

This review summarizes the research literature on the academic socialization of children within the family context. A conceptual model is introduced that describes the process of academic socialization, including parental experiences in school, parental school-related cognitions, and specific parenting behaviors. Parental attitudes and practices provide the foundation for children's development of schemas about school performance and thus are critical determinants of children's early school experiences. In addition, recent efforts to understand the role of transition practices aimed at facilitating children's early adjustment in school are described. The present review extends the transition practices literature by providing a developmental perspective on parenting influences on children's academic socialization, within an ecological systems perspective. The authors describe academic socialization as a process that occurs under the broad umbrella of socioeconomic and cultural contexts.
A Classification System for the Data of Personality Psychology and Adjoining Fields
Authors: Mayer John D.
Published: September 2004

Classes of data are often distinguished according to whether the person produces them, as is the case with self-report data or according to the type of test that produces them, for example, ability or personality tests. In a new classification system, data about personality are first divided according to whether they originate outside of the personality system (external source data) or inside it (personal report data). Personal report data are divided into life, world, self, and process report data. Data are further subdivided by the mental processes that produce each type (convergent thinking, divergent thinking, etc.) and then are connected to the measurement procedures that elicit the specific type. The new classification regularizes terminology and encourages new ways to think about data.
An embedded network approach for scale-up of fluctuation-driven systems with preservation of spike information
Authors: Cai David , Tao Louis , McLaughlin David W.
Published: September 2004

To address computational “scale-up” issues in modeling large regions of the cortex, many coarse-graining procedures have been invoked to obtain effective descriptions of neuronal network dynamics. However, because of local averaging in space and time, these methods do not contain detailed spike information and, thus, cannot be used to investigate, e.g., cortical mechanisms that are encoded through detailed spike-timing statistics. To retain high-order statistical information of spikes, we develop a hybrid theoretical framework that embeds a subnetwork of point neurons within, and fully interacting with, a coarse-grained network of dynamical background. We use a newly developed kinetic theory for the description of the coarse-grained background, in combination with a Poisson spike reconstruction procedure to ensure that our method applies to the fluctuation-driven regime as well as to the mean-driven regime. This embedded-network approach is verified to be dynamically accurate and numerically efficient. As an example, we use this embedded representation to construct “reverse-time correlations” as spiked-triggered averages in a ring model of orientation-tuning dynamics.
Cortical interneurons become activated by deafferentation and instruct the apoptosis of pyramidal neurons
Authors: Koliatsos V. E. , Dawson T. M. , Kecojevic A. , Zhou Yueping , Wang Yi-Feei , Huang K.-X.
Published: September 2004

Unlike peripheral nervous system neurons and certain groups of nerve cells in the CNS, cortical projection neurons are tolerant of axonal lesions. This resistance is incongruent with the massive death of pyramidal neurons in age-associated neurodegenerative diseases that proceed along corticocortical connections. Some insights have emerged from our previous work showing that pyramidal cells in piriform cortex undergo classical apoptosis within 24 h after bulbectomy via transsynaptic, but not retrograde, signaling. These findings allow the investigation of cellular and molecular changes that take place in the context of experimental cortical degeneration. In the present study, we show that the transsynaptic death of pyramidal neurons in piriform cortex is a nitric oxide-mediated event signaled by activated interneurons in layer I. Thus, we demonstrate that cortical interneurons play an essential role in transducing injury to apoptotic signaling that selectively targets pyramidal neurons. We propose that this mechanism may be generic to cortical degenerations and amenable to therapeutic interventions.
Evidence for conservation of architecture and physical properties of Omp85-like proteins throughout evolution
Authors: Surana Neeraj K. , Grass Susan , Hardy Gail G. , Li Huilin , Thanassi David G. , Geme Joseph W. St.
Published: September 2004

Omp85-like proteins represent a family of proteins involved in protein translocation, and they are present in all domains of life, except archaea. In eukaryotes, Omp85-like proteins have been demonstrated to form tetrameric pore-forming complexes that interact directly with their substrate proteins. Studies performed with bacterial Omp85-like proteins have demonstrated pore-forming activity but no evidence of multimerization. In this article, we characterize the
Haemophilus influenzae
HMW1B protein, an Omp85-like protein that has been demonstrated to be critical for secretion of the
H. influenzae
HMW1 adhesin. Analysis of purified protein by biochemical and electron microscopic techniques revealed that HMW1B forms a tetramer. Examination using liposome-swelling assays demonstrated that HMW1B has pore-forming activity, with a pore size of ≈2.7 nm. Far-Western blot analysis established that HMW1B interacts with the N terminus of HMW1. These results provide evidence that a bacterial Omp85-like protein forms a tetramer and interacts directly with a substrate protein, suggesting that the architecture and physical properties of Omp85-like proteins have been conserved throughout evolution.
Cancer regression in patients with metastatic melanoma after the transfer of autologous antitumor lymphocytes
Authors: Rosenberg Steven A. , Dudley Mark E.
Published: September 2004

Our recent clinical trials demonstrate that autologous cell transfer after lymphodepleting chemotherapy can cause the regression of large, vascularized tumors in patients with refractory metastatic melanoma. Eighteen of 35 patients treated with tumor-reactive lymphocyte cultures experienced an objective clinical response (>50% reduction in tumor), including four complete responders. In some patients, tumor regression was accompanied by a large
in vivo
expansion of the administered antitumor lymphocytes, which persisted in peripheral blood at >70% of total lymphocytes for many months after transfer. The cells capable of mediating tumor regression consisted of heterogeneous lymphocyte populations with high avidity for tumor antigens that were derived from tumor-infiltrating lymphocytes cultured for limited times
in vitro
. The success of this treatment likely results from the ability to infuse large numbers of activated antitumor lymphocytes into an appropriate host homeostatic environment depleted of regulatory T cells. These studies are elucidating the requirements for successful immunotherapy of patients with advanced metastatic disease and are leading to additional clinical trials with gene-modified lymphocytes.
Insect aquaplaning:
Nepenthes
pitcher plants capture prey with the peristome, a fully wettable water-lubricated anisotropic surface
Authors: Bohn Holger F. , Federle Walter
Published: September 2004

Pitcher plants of the genus
Nepenthes
have highly specialized leaves adapted to attract, capture, retain, and digest arthropod prey. Several mechanisms have been proposed for the capture of insects, ranging from slippery epicuticular wax crystals to downward-pointing lunate cells and alkaloid secretions that anesthetize insects. Here we report that perhaps the most important capture mechanism has thus far remained overlooked. It is based on special surface properties of the pitcher rim (peristome) and insect “aquaplaning.” The peristome is characterized by a regular microstructure with radial ridges of smooth overlapping epidermal cells, which form a series of steps toward the pitcher inside. This surface is completely wettable by nectar secreted at the inner margin of the peristome and by rain water, so that homogenous liquid films cover the surface under humid weather conditions. Only when wet, the peristome surface is slippery for insects, so that most ant visitors become trapped. By measuring friction forces of weaver ants (
Oecophylla smaragdina
) on the peristome surface of
Nepenthes bicalcarata
, we demonstrate that the two factors preventing insect attachment to the peristome, i.e., water lubrication and anisotropic surface topography, are effective against different attachment structures of the insect tarsus. Peristome water films disrupt attachment only for the soft adhesive pads but not for the claws, whereas surface topography leads to anisotropic friction only for the claws but not for the adhesive pads. Experiments on
Nepenthes alata
show that the trapping mechanism of the peristome is also essential in
Nepenthes
species with waxy inner pitcher walls.
Riparian deforestation, stream narrowing, and loss of stream ecosystem services
Authors: Sweeney Bernard W. , Bott Thomas L. , Jackson John K. , Kaplan Louis A. , Newbold J. Denis , Standley Laurel J. , Hession W. Cully , Horwitz Richard J.
Published: September 2004

A study of 16 streams in eastern North America shows that riparian deforestation causes channel narrowing, which reduces the total amount of stream habitat and ecosystem per unit channel length and compromises in-stream processing of pollutants. Wide forest reaches had more macroinvertebrates, total ecosystem processing of organic matter, and nitrogen uptake per unit channel length than contiguous narrow deforested reaches. Stream narrowing nullified any potential advantages of deforestation regarding abundance of fish, quality of dissolved organic matter, and pesticide degradation. These findings show that forested stream channels have a wider and more natural configuration, which significantly affects the total in-stream amount and activity of the ecosystem, including the processing of pollutants. The results reinforce both current policy of the United States that endorses riparian forest buffers as best management practice and federal and state programs that subsidize riparian reforestation for stream restoration and water quality. Not only do forest buffers prevent nonpoint source pollutants from entering small streams, they also enhance the in-stream processing of both nonpoint and point source pollutants, thereby reducing their impact on downstream rivers and estuaries.
Targeted disruption of the Walker–Warburg syndrome gene
Pomt1
in mouse results in embryonic lethality
Authors: Willer Tobias , Prados Belén , Falcón-Pérez Juan Manuel , Renner-Müller Ingrid , Przemeck Gerhard K. H. , Lommel Mark , Coloma Antonio , Valero M. Carmen , de Angelis Martin Hrabé , Tanner Widmar , Wolf Eckhard , Strahl Sabine , Cruces Jesús
Published: September 2004

O-mannosylation is an important protein modification in eukaryotes that is initiated by an evolutionarily conserved family of protein
O
-mannosyltransferases. The first mammalian protein
O
-mannosyltransferase gene described was the human
POMT1
. Mutations in the
hPOMT1
gene are responsible for Walker–Warburg syndrome (WWS), a severe recessive congenital muscular dystrophy associated with defects in neuronal migration that produce complex brain and eye abnormalities. During embryogenesis, the murine
Pomt1
gene is prominently expressed in the neural tube, the developing eye, and the mesenchyme. These sites of expression correlate with those in which the main tissue alterations are observed in WWS patients. We have inactivated a
Pomt1
allele by gene targeting in embryonic stem cells and produced chimeras transmitting the defect allele to offspring. Although heterozygous mice were viable and fertile, the total absence of
Pomt1

–
/
–

pups in the progeny of heterozygous intercrosses indicated that this genotype is embryonic lethal. An analysis of the mutant phenotype revealed that homozygous
Pomt1

–
/
–

mice suffer developmental arrest around embryonic day (E) 7.5 and die between E7.5 and E9.5. The
Pomt1

–
/
–

embryos present defects in the formation of Reichert's membrane, the first basement membrane to form in the embryo. The failure of this membrane to form appears to be the result of abnormal glycosylation and maturation of dystroglycan that may impair recruitment of laminin, a structural component required for the formation of Reichert's membrane in rodents. The targeted disruption of
mPomt1
represents an example of an engineered deletion of a known glycosyltransferase involved in
O
-mannosyl glycan synthesis.
Generation of methane in the Earth's mantle:
In situ
high pressure–temperature measurements of carbonate reduction
Authors: Scott Henry P. , Hemley Russell J. , Mao Ho-kwang , Herschbach Dudley R. , Fried Laurence E. , Howard W. Michael , Bastea Sorin
Published: September 2004

We present
in situ
observations of hydrocarbon formation via carbonate reduction at upper mantle pressures and temperatures. Methane was formed from FeO, CaCO
3
-calcite, and water at pressures between 5 and 11 GPa and temperatures ranging from 500°C to 1,500°C. The results are shown to be consistent with multiphase thermodynamic calculations based on the statistical mechanics of soft particle mixtures. The study demonstrates the existence of abiogenic pathways for the formation of hydrocarbons in the Earth's interior and suggests that the hydrocarbon budget of the bulk Earth may be larger than conventionally assumed.
The formation of spherulites by amyloid fibrils of bovine insulin
Authors: Krebs Mark R. H. , MacPhee Cait E. , Miller Aline F. , Dunlop Iain E. , Dobson Christopher M. , Donald Athene M.
Published: September 2004

Bovine insulin has long been known to self-assemblein vitrointo amyloid fibrils. We have observed a further higher-order self-association of the protein into spherical structures, with diameters typically around 50 μm but ranging from 10 to 150 μm. In a polarizing light microscope, these structures exhibit a “Maltese-cross” extinction pattern typical of spherulites. Spherical structures of a similar size distribution can be observed in the environmental scanning electron microscope, which also reveals the presence of significant amounts of water in the structures. The spherulites contain a large quantity of well defined amyloid fibrils, suggesting that they are formed at least in part as a consequence of the self-assembly of preformed fibrils. Similar structures also have been observed in the tissues of patients suffering from amyloid disorders. The ability of amyloid fibrils to form such higher-order assemblies supports the hypothesis that they represent a generic form of polypeptide structure with properties that are analogous to those of classical synthetic polymers.
IFN-γ enables cross-presentation of exogenous protein antigen in human Langerhans cells by potentiating maturation
Authors: Matsuo Mitsutoshi , Nagata Yasuhiro , Sato Eiichi , Atanackovic Djordje , Valmori Danila , Chen Yao-Tseng , Ritter Gerd , Mellman Ira , Old Lloyd J. , Gnjatic Sacha
Published: September 2004

We compared monocyte-derived dendritic cells and transforming growth factor-β1-induced Langerhans-like cells (LCs) for their capacity to cross-present exogenous NY-ESO-1 protein/antibody immune complexes to an NY-ESO-1-specific CD8+T cell clone. In contrast to dendritic cells, LCs were not able to cross-present NY-ESO-1 to the T cell clone constitutively but did so after treatment with IFN-γ. Remarkably, this IFN-γ-inducible characteristic was due neither to enhanced antigen uptake nor to facilitated antigen processing in LCs. Rather, IFN-γ acted at least in part by potentiating the maturation of otherwise refractory LCs, enabling in turn exogenous antigen to reach the processing machinery. This model of conditional cross-presentation establishes an original level of action for IFN-γ as an effective immune modulator and supports the use of IFN-γ in protein vaccination strategies targeting LCs.
Cryptochromes and neuronal-activity markers colocalize in the retina of migratory birds during magnetic orientation
Authors: Mouritsen Henrik , Janssen-Bienhold Ulrike , Liedvogel Miriam , Feenders Gesa , Stalleicken Julia , Dirks Petra , Weiler Reto
Published: September 2004

Migratory birds can use a magnetic compass for orientation during their migratory journeys covering thousands of kilometers. But how do they sense the reference direction provided by the Earth's magnetic field? Behavioral evidence and theoretical considerations have suggested that radical-pair processes in differently oriented, light-sensitive molecules of the retina could enable migratory birds to perceive the magnetic field as visual patterns. The cryptochromes (CRYs) have been suggested as the most likely candidate class of molecules, but do CRYs exist in the retina of migratory birds? Here, we show that at least one CRY1 and one CRY2 exist in the retina of migratory garden warblers and that garden-warbler CRY1 (gwCRY1) is cytosolic. We also show that gwCRY1 is concentrated in specific cells, particularly in ganglion cells and in large displaced ganglion cells, which also showed high levels of neuronal activity at night, when our garden warblers performed magnetic orientation. In addition, there seem to be striking differences in CRY1 expression between migratory and nonmigratory songbirds at night. The difference in CRY1 expression between migrants and nonmigrants is particularly pronounced in the large displaced ganglion cells known to project exclusively to a brain area where magnetically sensitive neurons have been reported. Consequently, cytosolic gwCRY1 is well placed to possibly be the primary magnetic-sensory molecule required for light-mediated magnetoreception.
A prominent role for the CBF cold response pathway in configuring the low-temperature metabolome ofArabidopsis
Authors: Cook Daniel , Fowler Sarah , Fiehn Oliver , Thomashow Michael F.
Published: September 2004

TheArabidopsisCBF cold response pathway has a central role in cold acclimation, the process whereby plants increase in freezing tolerance in response to low nonfreezing temperatures. Here we examined the changes that occur in theArabidopsismetabolome in response to low temperature and assessed the role of the CBF cold response pathway in bringing about these modifications. Of 434 metabolites monitored by GC-time-of-flight MS, 325 (75%) were found to increase inArabidopsisWassilewskija-2 (Ws-2) plants in response to low temperature. Of these 325 metabolites, 256 (79%) also increased in nonacclimated Ws-2 plants in response to overexpression of C-repeat/dehydration responsive element-binding factor (CBF)3. Extensive cold-induced changes also occurred in the metabolome ofArabidopsisCape Verde Islands-1 (Cvi-1) plants, which were found to be less freezing tolerant than Ws-2 plants. However, low-temperature-induced expression ofCBF1, CBF2, CBF3, and CBF-targeted genes was much lower in Cvi-1 than in Ws-2 plants, and the low-temperature metabolome of Cvi-1 plants was depleted in metabolites affected byCBF3overexpression. Taken together, the results indicate that the metabolome ofArabidopsisis extensively reconfigured in response to low temperature, and that the CBF cold response pathway has a prominent role in this process.
Nonergodic and conformational control of the electron capture dissociation of protein cations
Authors: Breuker Kathrin , Oh HanBin , Lin Cheng , Carpenter Barry K. , McLafferty Fred W.
Published: September 2004

Electron capture dissociation (ECD) MS is proving to be unusually valuable for “top down” protein sequencing and identification/localization of posttranslational modifications, because the ECD product ions can represent cleavages between most of a protein's amino acids. As proposed, this unusual reactivity results from immediate local utilization, before randomization, of much of the relatively large (≈6 eV) energy from the electron reaction with the multiply charged protein ion, minimizing the effect of differences in the backbone bond dissociation energies. However, others conclude that e–capture produces a labile free radical species for which backbone cleavage is the lowest energy reaction. Supporting the nonergodic mechanism, ECD of ubiquitin (M + 12H)12+ions also yields thermalized radical (M + 12H)11+·ions that instead lose H· when activated. Also, the ECD spectrum of ubiquitin (M + 13H)13+ions is nearly unchanged by heating from 25°C to 125°C, demonstrating that this increase in thermal energy is small compared to the energy driving the reaction. These results support initial capture of the electron in a long-lived high-nRydberg state, followed by internal conversion to the product valence state at an energy well above the dissociation barriers. The instantaneous conformation of the valence state is critical, with the observed products supporting an α-helical structure in which the protonated side chain of each basic residue is intercalated to hydrogen-bond to as many as three amide carbonyls. Activation (e.g., heat, collisions, lowered charge) can disrupt this conformation to allow additional H+-side-chain interactions and provide more complete sequence coverage.
Colorimetric detection of DNA sequences based on electrostatic interactions with unmodified gold nanoparticles
Authors: Li Huixiang , Rothberg Lewis
Published: September 2004

We find that single- and double-stranded oligonucleotides have different propensities to adsorb on gold nanoparticles in colloidal solution. We use this observation to design a hybridization assay based on color changes associated with gold aggregation. Because the underlying adsorption mechanism is electrostatic, no covalent functionalization of the gold, the probe, or the target DNA is required. Hybridization conditions can be optimized because it is completely separated from the detection step. The assay is complete within 5 min, and <100 femtomoles of target produces color changes observable without instrumentation. Single-base-pair mismatches are easily detected.
Single-nucleotide polymorphism discovery by targeted DNA photocleavage
Authors: Hart Jonathan R. , Johnson Martin D. , Barton Jacqueline K.
Published: September 2004

Single-nucleotide polymorphisms are the largest source of genetic variation in humans. We report a method for the discovery of single-nucleotide polymorphisms within genomic DNA. Pooled genomic samples are amplified, denatured, and annealed to generate mismatches at polymorphic DNA sites. Upon photoactivation, these DNA mismatches are then cleaved site-specifically by using a small molecular probe, a bulky metallointercalator, Rhchrysi or Rhphzi. Fluorescent labeling of the cleaved products and separation by capillary electrophoresis permits rapid identification with single-base resolution of the single-nucleotide polymorphism site. This method is remarkably sensitive and minor allele frequencies as low as 5% can be readily detected.
Functional significance of phytochemical lures to dacine fruit flies (Diptera: Tephritidae): an ecological and evolutionary synthesis
Authors: Raghu S.
Published: September 2004

While lures of plant origin are vital tools in dacine (Diptera: Tephritidae) pest management, the ecological and evolutionary significance of this lure response remains enigmatic. Two hypotheses (the ancestral host hypothesis and sexual selection by female choice) have been invoked to explain the functional significance of these chemicals to dacine fruit flies. These hypotheses are often treated as alternatives to one another and evidence favouring one is used to reject the other. This review highlights that these two hypotheses are not logical alternatives to each other as the ancestral host hypothesis attempts to explain the ultimate function of the response of Dacinae to these plant-derived parapheromones while the sexual selection hypothesis provides a proximate explanation for lure response. Research on lure response, dacine mating behaviour, functional significance of lures, plant phylogeny and biochemistry and dacine pheromone chemistry are used to evaluate the evidence in relation to both these hypotheses. Some of the key findings are that there is evidence both in support of and against these two hypotheses. Response of fruit flies to related phenyl propanoids to those commonly used as lures in pest management and distribution of phenyl propanoids attractive to dacines among plant orders strongly support the ancestral host hypothesis. Evidence from pheromone chemistry, dacine mating behaviour and the functional significance of lures both support and contradict the sexual selection hypothesis. Lures appear to have different proximate functions in different dacine species. Considerably greater research is needed to clarify the functional role of phytochemical lures to dacine fruit flies. The two prevalent hypotheses should be investigated independently. Specific research on dacine phylogeny and distribution of lures in plants in relation to ecological roles played by adult dacines is required to elucidate the ultimate roles of the chemicals. Exploration of female response to lures and the behavioural consequences of dacine response to these chemicals to both the insect and plant may shed light on the proximate functions of these chemicals.
Unexpected Listronotus bonariensis (Coleoptera: Curculionidae) mortality in the presence of parasitoids
Authors: Goldson S.L. , Proffitt J.R. , McNeill M.R. , Phillips C.B. , Barlow N.D. , Baird D.B.
Published: September 2004

Field enclosure and laboratory cage experiments designed to measure the impact of the parasitoid Microctonus hyperodae Loan on the Argentine stem weevil, Listronotus bonariensis (Kuschel) have shown that under high parasitoid pressure, there is significant weevil mortality without obvious parasitism. Parasitoid-exposed, but unparasitized portions of caged populations died at rates significantly higher than both the parasitized weevils from the same population and the unexposed controls. Unexpectedly, parasitized weevils had the lowest mortality rates (prior to larval parasitoid emergence). It was of ecological significance that this mortality effect was detected under field conditions using several years of empirically-collected population dynamics data. Under both field and laboratory conditions this mortality was found to occur within shorter time intervals than that required for full parasitoid larval development; thus it could not be attributed to the mortality that occurs after the emergence of prepupal parasitoids. The mechanism for this mortality remains undetermined, although it could possibly be linked to pseudoparasitism.
A PCR-based approach to distinguish important Diadegma species (Hymenoptera: Ichneumonidae) associated with diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)
Authors: Wagener B. , Reineke A. , Löhr B. , Zebitz C.P.W.
Published: September 2004

The diamondback moth, Plutella xylostella (Linnaeus) has a cosmopolitan distribution and is one of the major pests on cruciferous plants. Biological control, especially with species of the genus Diadegma, has been successfully employed in several parts of the world, mainly in South East Asia. The taxonomy of this genus based on classical morphological characters is still unclear and misidentifications are reported. In the present study seven Diadegma species associated with P. xylostella were separated using polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) analyses. The second internal transcribed spacer (ITS2) of the ribosomal DNA (rDNA) was successfully amplified in all 167 individuals and digested using 11 different restriction enzymes. One restriction enzyme (CfoI) showed different restriction profiles in all species and also between two population samples of D. mollipla (Holmgren) from eastern and southern Africa. In addition, a new Diadegma species associated with P. xylostella from Ethiopia was discovered.
Responses of adult mosquitoes of two sibling species,Anopheles arabiensisandA. gambiaes.s. (Diptera: Culicidae), to high temperatures
Authors: Kirby M.J. , Lindsay S.W.
Published: September 2004

It is well known that amongst the sibling species of theAnopheles gambiaecomplex,A. arabiensisPatton predominates overA. gambiaesensu stricto Giles in hotter, drier parts of Africa. Here it was investigated whetherA. arabiensisis better adapted to higher temperatures thanA. gambiaes.s. at the microclimatic level. Bioassays were used to assess behavioural avoidance activity of adult mosquitoes in the presence of increasing temperature. Female mosquitoes were introduced into a holding tube from which they could escape into a cage through a one-way funnel. From a starting temperature of 28°C they were exposed to a 2°C rise in temperature every 30 min until all mosquitoes had escaped or been knocked down. As temperature increased,A. arabiensisleft the holding tube at higher temperatures thanA. gambiaes.s. (A. arabiensismean activation temperature = 35.7°C, 95% CIs = 35.4–36.1°C;A. gambiaes.s. = 33.0°C, 32.5–33.5°C). To determine the relative ability of both species to survive at extremely high temperatures, batches of insects were exposed to 40°C for different periods. It took considerably longer to kill 50% ofA. arabiensisat 40°C than it didA. gambiaes.s. (112 min vs. 67 min). These data show that adultA. arabiensisare better adapted to hotter conditions thanA. gambiaes.s., a characteristic that is reflected in their spatial and temporal distribution in Africa.
Host plant recognition by the root feeding clover weevil, Sitona lepidus (Coleoptera: Curculionidae)
Authors: Johnson S.N. , Gregory P.J. , Murray P.J. , Zhang X , Young I.M.
Published: September 2004

This study investigated the ability of neonatal larvae of the root-feeding weevil, Sitona lepidus Gyllenhal, to locate white clover Trifolium repens L. (Fabaceae) roots growing in soil and to distinguish them from the roots of other species of clover and a co-occurring grass species. Choice experiments used a combination of invasive techniques and the novel technique of high resolution X-ray microtomography to non-invasively track larval movement in the soil towards plant roots. Burrowing distances towards roots of different plant species were also examined. Newly hatched S. lepidus recognized T. repens roots and moved preferentially towards them when given a choice of roots of subterranean clover, Trifolium subterraneum L. (Fabaceae), strawberry clover Trifolium fragiferum L. (Fabaceae), or perennial ryegrass Lolium perenneL. (Poaceae). Larvae recognized T. repens roots, whether released in groups of five or singly, when released 25 mm (meso-scale recognition) or 60 mm (macro-scale recognition) away from plant roots. There was no statistically significant difference in movement rates of larvae.
Two different life-history strategies determine the competitive outcome between Dirhinus giffardii (Chalcididae) and Pachycrepoideus vindemmiae (Pteromalidae), ectoparasitoids of cyclorrhaphous Diptera
Authors: Wang X.G. , Messing R.H.
Published: September 2004

Dirhinus giffardii Silvestri and Pachycrepoideus vindemmiae Rondani are solitary parasitoids attacking puparia of many cyclorrhaphous flies. They are not typical ectoparasitoids, as they feed on host pupae within puparia that develop from the exoskeleton of host larvae. Dirhinus giffardii did not kill its host until the parasitoid egg developed into a larva, while P. vindemmiae permanently paralysed its host at the time of oviposition. As a result, ovipositing into a young host puparium (< 1 day old) in which the host pupa has not yet fully formed resulted in complete death of offspring in P. vindemmiae, but D. giffardii, although suffering higher mortality than in older host puparia, still showed a level of successful development. In a choice experiment, both parasitoids preferred to attack 2- to 3-day-old puparia in which the host pupae had fully formed, rather than 1-day-old host puparia. Pachycrepoideus vindemmiae always prevailed in competition because it injected venom that not only paralysed the host, but also caused the death of D. giffardii larvae in multi-parasitized hosts. Dirhinus giffardii preferred to attack unparasitized hosts rather than hosts previously parasitized by P. vindemmiae, while P. vindemmiae did not show a preference between unparasitized hosts and hosts previously parasitized by D. giffardii.
The spatial dynamics of crop and ground active predatory arthropods and their aphid prey in winter wheat
Authors: Holland J.M. , Winder L. , Woolley C. , Alexander C.J. , Perry J.N.
Published: September 2004

The distribution of aphid predators within arable fields has been previously examined using pitfall traps. With this technique predominantly larger invertebrate species are captured, especially Carabidae, but the technique provides no estimate of density unless mark–recapture is used. However, many other numerically important aphid predators occur in arable fields and relatively little is known about their distribution patterns nor whether they exhibit a density-dependent response to patches of cereal aphids. Identification of the most effective predators can allow management practices to be developed accordingly. In this study, the distribution of cereal aphids and their predators was examined by suction sampling within a field of winter wheat in Devon, UK, along with visual estimates of weed patchiness. Sampling was conducted on four occasions in 1999 across a grid of 128 sample locations. The distribution of 11 predatory taxa from the Carabidae, Staphylinidae and Linyphiidae was examined. Additionally, the total number of aphid predators and a predation index were used in these analyses. Carabid adults and larvae, along with staphylinid larvae showed the strongest aggregation into patches and the most temporal stability in their distribution. Other taxa had more ephemeral distributions as did the cereal aphids. The distribution of carabid larvae was disassociated from the distribution of cereal aphids for the first two sampling occasions indicating biocontrol was occurring. Other predatory groups showed both association and disassociation. Carabid larvae,Bathyphantesand total numbers of Linyphiidae showed a strong correlation with weed cover for two of the sample dates. Cereal aphids were disassociated from weed cover on three sampling occasions.
Implementing the foundation stage in reception classes1
Authors: Aubrey Carol
Published: September 2004

This article draws upon a Department for Education and Skills (DfES) commissioned telephone survey of a nationally representative sample of schools to investigate the challenges faced by those seeking the successful implementation of the Foundation Stage (FS) (for 3–5‐year‐olds) in reception classes. Its focuses on head teachers' and reception teachers' own reported knowledge, perspectives, experiences, attitudes and views about reception practice, as well as background information on provision and teacher characteristics. A vast and rich amount of data was gathered providing a snapshot of practices and opinions related to the second year of implementing the FS. The majority of head teachers and reception teachers had a positive view of the FS and progress made in implementing it. In general, implementation of the National Literacy and Numeracy Strategies, transition to Key Stage 1 and planning opportunities for children to engage in activities they had planned and initiated themselves was not regarded as a problem. The survey highlighted the importance of staff training and the need to extend this. Greatest concerns were expressed in schools with mixed‐age classes, teaching two curricula with distinct pedagogies. It is concluded that schools in both urban and rural/mainly rural areas have distinct, though similarly diverse teaching groups. A wide range of teaching strategies, based on children's diverse needs, will be required to motivate, support and extend them appropriately. The results are interrogated from the perspective of relevant research carried out during the same period.
Developing the spoken language skills of reception class children in two multicultural, inner‐city primary schools
Authors: Riley Jeni , Burrell Andrew , McCallum Bet
Published: September 2004

This article describes a small‐scale study which emanated from the concern of the head teachers and staff of two primary schools serving deprived, multicultural areas of an inner city. The concern of the staff related to the level of their pupils' spoken language skills through the schools and the perceived impact that this has on pupils learning more widely. The article explores the nature and importance of oral language development in the early years and describes an intervention designed to enhance the spoken language skills of the reception children. The pre‐intervention scores of the children at school entry indicated that the language skills of the children were less well developed than those of the general population. The findings suggest that the intervention had a positive effect on the speaking and listening skills of the reception children and that the teachers' involvement in the research contributed to their professional development.