bluuebunny/crossref_metadata_2025 huggingface dataset:
Governance, economic policy, and the environmental Kuznets curve for natural tropical forests
Authors: BHATTARAI MADHUSUDAN , HAMMIG MICHAEL
Published: May 2004

This paper reports the results of an empirical analysis of the relationship between income and the rate of deforestation of tropical natural forests. The inverted U-shaped relationship known as the environmental Kuznets curve is confirmed. The study focuses on the role of institutions and macroeconomic policy in the deforestation process. Results indicate that the quality of governance is an important determinant of forest resource preservation, and that rural population pressure is not as important as suggested by other studies. Agricultural technology improvement and enhanced educational attainment also lead to reductions of deforestation rates.
Consumption pattern, trade, and greenhouse gas leakage in India
Authors: SENGUPTA RAMPRASAD , BHARDWAJ GEETESH
Published: May 2004

The policy discussions for sharing the global responsibility for abatement of greenhouse gas (GHG) emissions by individual countries take account neither of the pattern of their final consumption nor of the role of globalization through trade in the leakage of GHGs across national boundaries. This paper gives the methodology of estimating the total emissions of a GHG, which is imputable to the consumption pattern of a country and the effect of trade on the net leakage of such gas. The paper estimates the effect of trade on the net leakage of carbon dioxide and methane from India. It shows a significant net leakage of carbon dioxide from India for the observed consumption pattern in the 1990s. In spite of the difficulty of application of the method of estimating the leakage due to data constraints regarding regularly updated input–output tables for the different countries, the results point to the necessity of using some policy measure to influence globally the preference structure of the people in favour of eco-friendly consumption patterns.
Summaries
Authors: HONLONKOU ALBERT N. , YAP ROBERTO C. , SENGUPTA RAMPRASAD , BHARDWAJ GEETESH , KANG SANG MOK , LEE MYUNGHUN , BHATTARAI MADHUSUDAN , HAMMIG MICHAEL , AMMAN HANS M. , DURAIAPPAH ANANTHA KUMAR , DINAR ARIEL , BALAKRISHNAN TRICHUR K. , WAMBIA JOSEPH
Published: May 2004

Modelling adoption of natural resources management technologies: the case of fallow systems

Option valuation of Philippine forest plantation leases

Consumption pattern, trade, and greenhouse gas leakage in India

An empirical study on effective pollution enforcement in Korea

Governance, economic policy, and the environmental Kuznets curve for natural tropical forests

Land tenure and conflict resolution: a game theoretic approach in the Narok district in Kenya

Politics of institutional reforms in the water and drainage sector of Pakistan
An atmospheric turbulent velocity spectrum for three dimensions
Authors: Thebaud L.
Published: May 2004

A simple parametric model is developed that extends and unifies the usual phenomenological description of turbulent atmospheric velocity variances and correlations. The multidimensional spectral model thus defined allows any second‐order statistical quantity involving velocity to be calculated. The model parameters are determined by fitting them to published single‐point measurements of temporal spectra over land, which shows the ability of the model to efficiently and naturally account for observed differences in the low‐frequency behavior of spectra for different velocity components. The scheme is first tested by comparing its predictions for correlations to other data. The utility of the model is illustrated and its predictions are further tested by comparing to a set of optical ocean image data that exposes the two‐dimensional patterns of wind speed fluctuations in Taylorized flow. These exhibit the predicted anisotropy of the spectrum. Some detailed issues in the model for optical response to wind fluctuations are discussed.
Open‐closed field line boundary position: A parametric study using an MHD model
Authors: Kabin K. , Rankin R. , Rostoker G. , Marchand R. , Rae I. J. , Ridley A. J. , Gombosi T. I. , Clauer C. R. , DeZeeuw D. L.
Published: May 2004

In this paper we investigate the effect of changes in the interplanetary magnetic field (IMF), solar wind dynamic pressure, and dipole tilt angle on the position of the ionospheric projection of the open‐closed field line boundary (OCB) in a magnetohydrodynamic (MHD) model. We carry out a large number of steady state global MHD simulations in order to parameterize the OCB as a function of the solar wind By and Bz which we find to have the largest effect on the OCB location. We interpolate between the values produced by the simulations, which allows us to evaluate the location of the OCB projection into the ionosphere for any values of ∣By∣ < 10 nT and ∣Bz∣ < 10 nT. It is found that, particularly on the nightside, the OCB position is very sensitive to changes in the northward IMF component Bz, but it is much less sensitive to changes in Bz when it is southward. The response of the OCB location to changes in By also depends greatly on whether Bz is northward or southward, being much larger in situations in which Bz > 0 nT. We also find that the polar cap area increases with the increasing solar wind dynamic pressure. The Bx component of the IMF and the dipole tilt angle are found to have relatively small effects on the location of the OCB.
Reactive geothermal transport simulations to study the formation mechanism of an impermeable barrier between acidic and neutral fluid zones in the Onikobe Geothermal Field, Japan
Authors: Todaka Norifumi , Akasaka Chitoshi , Xu Tianfu , Pruess Karsten
Published: May 2004

Two types of fluids are encountered in the Onikobe geothermal reservoir (Japan): one is neutral and the other is acidic. It is hypothesized that acidic fluid might be upwelling along a fault zone from magma and that an impermeable barrier might be present between the acidic and neutral fluid zones. To test such a conceptual model and to study the geochemical behavior due to mixing of the two fluids, reactive geothermal transport simulations under both natural and production conditions were carried out using the code TOUGHREACT. Results indicate Mn‐rich smectite precipitates near the mixing front. Precipitation of sphalerite and galena occurs in a similar region as the Mn‐rich smectite. Precipitation of these minerals depends on pH and temperature. In addition, quartz, pyrite, and calcite precipitate in the shallow zone resulting in further development of caprock. The changes in porosity and permeability due to precipitation of Mn‐rich smectite are small compared with that of quartz, calcite, and pyrite. However, the smectite precipitation is likely to fill open fractures and to form an impermeable barrier between acidic and neutral fluid regions. The simulated mineral assemblage is generally consistent with observations in the Onikobe field. The numerical simulations described here provide useful insight into geochemical behavior and formation of impermeable barriers from fluid mixing. The method presented in this paper may be useful in fundamental analysis of hydrothermal systems and in the exploration of geothermal reservoirs, including chemical evolution, mineral alteration, mineral scaling, and changes in porosity and permeability.
Neural network uncertainty assessment using Bayesian statistics with application to remote sensing: 1. Network weights
Authors: Aires F.
Published: May 2004

Neural network techniques have proved successful for many inversion problems in remote sensing; however, uncertainty estimates are rarely provided. This study has three parts. In this article, we present an approach to evaluate uncertainties (i.e., error bars and the correlation structure of these errors) of the neural network parameters, the so‐called “synaptic weights” on the basis of a Bayesian technique. In contrast to more traditional approaches based on “point estimation” of the neural network weights (i.e., only one set of weights is determined by the learning process), we assess uncertainties on such estimates to monitor the quality of the neural network model. Uncertainties of the network parameters are used in the following two papers to estimate uncertainties of the network output [Aires et al., 2004a] and of the network Jacobians [Aires et al., 2004b]. These new theoretical developments are illustrated by applying them to the problem of retrieving surface skin temperature, microwave surface emissivities, and integrated water vapor content from a combined analysis of microwave and infrared observations over land.
Neural network uncertainty assessment using Bayesian statistics with application to remote sensing: 2. Output errors
Authors: Aires F. , Prigent C. , Rossow W. B.
Published: May 2004

A technique to estimate the uncertainties of the parameters of a neural network model, i.e., the synaptic weights, was described in the work of Aires [2004]. Using these weight uncertainty estimates, we compute the uncertainties in the network outputs (i.e., error bars and correlation structure of these errors). Such quantities are very important for evaluating any application of the neural network technique. The theory is applied to the same remote sensing problem as in the work of Aires [2004] concerning the retrieval of surface skin temperature, microwave surface emissivities and integrated water vapor content from a combined analysis of microwave and infrared observations over land.
Neural network uncertainty assessment using Bayesian statistics with application to remote sensing: 3. Network Jacobians
Authors: Aires F. , Prigent C. , Rossow W. B.
Published: May 2004

Used for regression fitting, neural network (NN) models can be used effectively to represent highly nonlinear, multivariate functions. In this situation, most emphasis has been on estimating the output errors, but almost no attention has been given to errors associated with the internal structure of the NN model. The complex relationships linking the inputs to the outputs inside the network are the essence of the model and assessing their physical meaning makes all the difference between a “black box” model with small output errors and a physically meaningful model that will provide insight on the problem and will have better generalization properties. Such dependency structures can, for example, be described by the NN Jacobians: they indicate the sensitivity of one output with respect to the inputs of the model. Estimating these Jacobians is essential for many other applications as well. We use a new method of uncertainty estimate developed in the work of Aires [2004] to investigate the robustness of the quantities that characterize the NN structure. A regularization strategy based on principal component analysis is proposed to suppress the multicolinearities that are a major concern when analyzing the internal structure of such a model. The theory is applied to the remote sensing application already presented in the work of Aires [2004] and Aires et al. [2004].
Observation of solar particle event on board a commercial flight from Los Angeles to New York on 29 October 2003
Authors: Getley Ian L.
Published: May 2004

The enhanced radiation associated with solar particle events and in particular the secondary ionization doses created by the neutron flux in the upper atmosphere resulting from both cosmic ray and solar particle interaction with constituents of the atmosphere, pose an additional significant risk to both aircrew and passengers at aircraft altitude. Whilst the elevated x‐ray component from a solar flare or coronal mass ejection (CME) can be significant, the effects of large particle events to the secondary radiation environment at jet aircraft cruising altitudes, can have consequences for both people and micro electronics used in modern generation aircraft. It has been shown that dose rates increase with higher latitudes and altitudes, and due to the geomagnetic field effect that deflects incoming solar and galactic cosmic rays, we get greater shielding closer to the equator. Generally increasing latitude appears to have a greater effect on increasing secondary radiation than altitude alone and this is certainly so during a solar flare or solar particle event.
Lateral mixing in the Mississippi River below the confluence with the Ohio River
Authors: Rathbun R. E. , Rostad C. E.
Published: May 2004

Lateral dispersion coefficients for two dispersants were determined for three sections of the Mississippi River below the confluence with the Ohio River. The dispersants were the specific conductance and an industrial organic compound (trimethyltriazinetrione). Three models based on the stream tube concept were used, and lateral dispersion coefficients computed from these models were comparable. Coefficients for the two dispersants also were comparable. Lateral dispersion coefficients were consistent with expectations based on the characteristics of the river sections. Overall average values were 0.444 m2/s for a relatively straight section of river, 1.69 m2/s for a section containing two sharp bends, and 2.22 m2/s for a long section containing four sharp bends and several small islands. The lateral dispersion coefficients measured for the Mississippi River are consistent with literature data and a water discharge relation. Results of this study provide lateral dispersion coefficients for a water discharge not previously reported in the literature as well as new values for the Mississippi River.
Subsurface flow and vegetation patterns in tidal environments
Authors: Ursino Nadia , Silvestri Sonia , Marani Marco
Published: May 2004

Tidal environments are characterized by a complex interplay of hydrological, geomorphic, and biological processes, and their understanding and modeling thus require the explicit description of both their biotic and abiotic components. In particular, the presence and spatial distribution of salt marsh vegetation (a key factor in the stabilization of the surface soil) have been suggested to be related to topographic factors and to soil moisture patterns, but a general, process‐based comprehension of this relationship has not yet been achieved. The present paper describes a finite element model of saturated‐unsaturated subsurface flow in a schematic salt marsh, driven by tidal fluctuations and evapotranspiration. The conditions leading to the establishment of preferentially aerated subsurface zones are studied, and inferences regarding the development and spatial distribution of salt marsh vegetation are drawn, with important implications for the overall ecogeomorphological dynamics of tidal environments. Our results show that subsurface water flow in the marsh induces complex water table dynamics, even when the tidal forcing has a simple sinusoidal form. The definition of a space‐dependent aeration time is then proposed to characterize root aeration. The model shows that salt marsh subsurface flow depends on the distance from the nearest creek or channel and that the subsurface water movement near tidal creeks is both vertical and horizontal, while farther from creeks, it is primarily vertical. Moreover, the study shows that if the soil saturated conductivity is relatively low (10−6 m s−1, values quite common in salt marsh areas), a persistently unsaturated zone is present below the soil surface even after the tide has flooded the marsh; this provides evidence of the presence of an aerated layer allowing a prolonged presence of oxygen for aerobic root respiration. The results further show that plant transpiration increases the extent and persistence of the aerated layer, thereby introducing a strong positive feedback: Pioneer plants on marsh edges have the effect of increasing soil oxygen availability, thus creating the conditions for the further development of other plant communities.
Preseismic groundwater level changes induced by crustal deformations related to earthquake swarms off the east coast of Izu Peninsula, Japan
Authors: Koizumi Naoji , Kitagawa Yuichi , Matsumoto Norio , Takahashi Makoto , Sato Tsutomu , Kamigaichi Osamu , Nakamura Koji
Published: May 2004

Groundwater level changes since October 1994 of Omuroyama‐kita (OMR) well in Izu Peninsula, Japan, were examined in relation to six earthquake swarms with which large crustal deformations were accompanied. After removing not only tidal and barometric effects but rainfall effect on groundwater, we detected four preseismic groundwater level changes accompanied with crustal deformations recorded at nearby stations. Those groundwater level changes are interpreted to have caused by crustal deformations or volumetric strain changes which seem to be caused by dike intrusions, which are possible sources of the earthquake swarms off the east coast of Izu Peninsula.
Mass and water transport into the tropical stratosphere: A cloud‐resolving simulation
Authors: Küpper Christoph , Thuburn John , Craig George C. , Birner Thomas
Published: May 2004

A three‐dimensional cloud‐resolving model is used to investigate the relative contributions of cumulus clouds and slow, large‐scale nonconvective ascent to the transport of mass and moisture into the tropical stratosphere. When run to equilibrium, the simulation reproduces key features of the thermal and cloud structure in the tropical tropopause region, including a sharp cold point with a thin cirrus layer above the level of cumulus outflow. The simulated nonconvective mass flux into the stratosphere is 2 orders of magnitude greater than the cumulus mass flux, and the nonconvective water flux is several times greater than the cumulus water flux. The water content of air entering the stratosphere is controlled by the coldest temperature experienced by the air during its slow nonconvective ascent. Temperature fluctuations associated with convectively generated gravity waves reduce this coldest temperature slightly below that of the large‐scale temperature minimum.
Acute and long‐term effects of nateglinide on insulin secretory pathways
Authors: Ball Andrew J , Flatt Peter R , McClenaghan Neville H
Published: May 2004

Acute and chronic effects of the insulinotropic drug nateglinide upon insulin release were examined in the BRIN‐BD11 cell line.

Nateglinide (10–400 μM) stimulated a concentration‐dependent increase (P<0.05–P<0.001) in insulin release at a non‐stimulatory (1.1 mM) glucose concentration. The insulinotropic response to 200 μM nateglinide was increased at 30 mM (P<0.01), but not 5.6–16.7 mM glucose concentrations.

In depolarized cells, nateglinide (50–200 μM) evoked KATP channel‐independent insulin secretion (P<0.05–P<0.001) in the absence and presence of 5.6–30.0 mM glucose (P<0.001).

Exposure for 18 h to 100 μM nateglinide abolished the acute insulinotropic effects of 200 μM nateglinide, tolbutamide or glibenclamide, but had no effect upon the insulinotropic effect of 200 μM efaroxan.

While 18 h exposure to 100 μM nateglinide did not affect basal insulin release or insulin release in the presence of 16.7 mM glucose, 25 μM forskolin or 10 nM PMA, significant inhibition of the insulinotropic effects of 20 mM leucine and 20 mM arginine were observed.

These data show that nateglinide stimulates both KATP channel‐dependent and‐independent insulin secretion. The maintained insulinotropic effects of this drug with increasing glucose concentrations support the antihyperglycaemic actions of nateglinide in Type II diabetes.

Studies of the long‐term effects of nateglinide indicate that nateglinide shares signalling pathways with sulphonylureas, but not the imidazoline efaroxan. This may be significant when considering a nateglinide treatment regimen, particularly in patients previously treated with sulphonylurea.

British Journal of Pharmacology (2004) 142, 367–373. doi:10.1038/sj.bjp.0705766
Remodelling of the PDE4 cAMP phosphodiesterase isoform profile upon monocyte‐macrophage differentiation of human U937 cells
Authors: Shepherd Malcolm C , Baillie George S , Stirling David I , Houslay Miles D
Published: May 2004

Monocytes and macrophages provide key targets for the action of novel anti‐inflammatory therapeutics targeted at inhibition of PDE4 cAMP‐specific phosphodiesterases.

PDE4 enzymes provide the dominant cAMP phosphodiesterase activity in U937 human monocytic cells.

Differentiation of U937 monocytic cells to a macrophage‐like phenotype causes a marked reduction in total cellular PDE4 activity.

Monocytic U937 cells express the long PDE4A4, PDE4D5 and PDE4D3 isoforms plus the short PDE4B2 isoform. Differentiation of U937 cells to a macrophage‐like phenotype causes a marked downregulation of PDE4D3 and PDE4D5, elicits a marked upregulation of PDE4B2 and induces the novel PDE4A10 long isoform. Comparable patterns are found in human peripheral blood monocytes and macrophages differentiated from them.

Immunopurification of PDE4 subfamilies identifies long PDE4D isoforms as providing the major PDE4 activity in U937 monocytic cells.

In U937 macrophage‐like cells, the activity of the short PDE4B2 isoform predominates.

No indication of either the expression or induction of PDE4C was evident.

Activation of ERK exerts an inhibitory effect on total PDE4 activity in monocytic U937 cells, where the activity of long PDE4 isoforms predominates.

The effect of ERK activation is switched to one of overall stimulation of total PDE4 activity in macrophage U937 cells, where the activity of the short PDE4B2 isoform predominates.

The profound differentiation‐induced changes in PDE4 isoform profile identified here suggests that the development of inhibitors specific for particular PDE4 isoforms may allow for selective effects on monocytes and macrophages to be achieved.

British Journal of Pharmacology (2004) 142, 339–351. doi:10.1038/sj.bjp.0705770
Molecular mechanisms of vasoselectivity of the 1,4‐dihydropyridine lercanidipine
Authors: Wirtz Susanne , Herzig Stefan
Published: May 2004

The effects of (S)‐ and (R)‐lercanidipine on CHO cells stably expressing the cardiac (Cav1.2a) or vascular (Cav1.2b) splice variant of the L‐type calcium channel pore subunit were studied, using whole‐cell and single‐channel patch‐clamp measurements.

Lercanidipine block of Cav1.2b current was enantioselective. (S)‐lercanidipine was 4.1‐fold more potent.

Experiments using acidic solutions (pH 6.8) revealed a 6.4‐fold enhanced inhibitory effect of (S)‐lercanidipine compared with physiological conditions (pH 7.4) indicating that the charged form mediates inhibition.

At depolarised holding potential (−40 mV), (S)‐lercanidipine exhibited a 35‐fold greater potency, compared with standard conditions (−80 mV).

A comparison of the concentration‐dependent inhibition of Cav1.2a with Cav1.2b subunit currents by (S)‐lercanidipine revealed only a 1.8‐fold difference in IC50, but the slope of the dose–response curve was much steeper (nH=2.3) with Cav1.2a, compared with Cav1.2b (nH=0.8). This indicates overlap between agonistic and antagonistic effects, predominant with the cardiac Cav1.2a subunit. This idea is supported by transient stimulatory effects, and a slight leftward shift of the IV curves. These effects were more prominent for Cav1.2a than for Cav1.2b.

Single‐channel experiments confirmed typical features of calcium channel agonists such as prolonged channel openings, a component of lengthened openings, and an enhanced open probability in the presence of (S)‐lercanidipine. Again, these findings were concentration‐dependent and more pronounced for Cav1.2a than for Cav1.2b.

Our data indicate a splice‐variant predominant agonism as a new mechanism contributing to the vasoselectivity of lercanidipine, along with marked voltage‐dependence of action.

British Journal of Pharmacology (2004) 142, 275–284. doi:10.1038/sj.bjp.0705786
A concise, total synthesis of the TMC-95A/B proteasome inhibitors
Authors: Albrecht Brian K. , Williams Robert M.
Published: May 2004

A concise, total synthesis of the proteasome inhibitors TMC-95A/B has been accomplished. The synthesis features the use of an
l
-serine-derived
E
-selective modified Julia olefination reaction to ultimately control the stereochemical outcome of the highly oxidized tryptophan fragment. Additionally, the limited use of protecting groups at a late stage of the total synthesis allowed for its completion in an efficient manner.
Variation in xylem structure from tropics to tundra: Evidence from vestured pits
Authors: Jansen Steven , Baas Pieter , Gasson Peter , Lens Frederic , Smets Erik
Published: May 2004

Bordered pits play an important role in permitting water flow among adjacent tracheary elements in flowering plants. Variation in the bordered pit structure is suggested to be adaptive in optimally balancing the conflict between hydraulic efficiency (conductivity) and safety from air entry at the pit membrane (air seeding). The possible function of vestured pits, which are bordered pits with protuberances from the secondary cell wall of the pit chamber, could be increased hydraulic resistance or minimized vulnerability to air seeding. These functional hypotheses have to be harmonized with the notion that the vestured or nonvestured nature of pits contains strong phylogenetic signals (i.e., often characterize large species-rich clades with broad ecological ranges). A literature survey of 11,843 species covering 6,428 genera from diverse climates indicates that the incidence of vestured pits considerably decreases from tropics to tundra. The highest frequencies of vestured pits occur in deserts and tropical seasonal woodlands. Moreover, a distinctly developed network of branched vestures is mainly restricted to warm habitats in both mesic and dry (sub)tropical lowlands, whereas vestures in woody plants from cold and boreal arctic environments are usually minute and simple. A similar survey of the frequency of exclusively scalariform perforation plates illustrates that the major ecological trend of this feature is opposite that of vestured pits. These findings provide previously undescribed insights suggesting that vessels with vestured pits and simple perforation plates function as an efficient hydraulic system in plants growing in warm environments with periodical or continuous drought stress.
Distinct migrating and nonmigrating dendritic cell populations are involved in MHC class I-restricted antigen presentation after lung infection with virus
Authors: Belz Gabrielle T. , Smith Christopher M. , Kleinert Lauren , Reading Patrick , Brooks Andrew , Shortman Ken , Carbone Francis R. , Heath William R.
Published: May 2004

During lung infection with virus, airway-derived dendritic cells (DC) have been thought to be the dominant cell type involved in acquisition, transport, and direct antigen presentation for cytotoxic T lymphocyte priming. Contrary to this view, we have found that both an airway-derived CD8α
–
CD11b
–
DC subset and distinct CD8α
+
lymph node resident DC can present class I-restricted antigens after lung infection with influenza virus or herpes simplex virus 1. Presentation by a nonairway-derived DC population argues that cytotoxic T lymphocyte priming may involve interplay between different DC subsets, not all of which originate within the site of infection.
Seven in absentia homolog 1A mediates ubiquitination and degradation of group 1 metabotropic glutamate receptors
Authors: Moriyoshi Koki , Iijima Kouichirou , Fujii Hajime , Ito Hiroshi , Cho Yoshimi , Nakanishi Shigetada
Published: May 2004

Seven in absentia homolog 1A (Siah1A) is a member of the RING-finger-containing E3 ubiquitin ligases and has been shown to bind to the Siah-interacting domain (SID) at the carboxyl-terminal tails of the long splice forms of group 1 metabotropic glutamate receptors (mGluR1a and mGluR5). We examined the function of Siah1A in ubiquitination and degradation of group 1 mGluRs in heterologously expressing cell lines. Coexpression of Siah1A markedly decreased the SID-containing splice forms of group 1 mGluRs but not the SID-lacking mGluR1b splice form or the SID-deleted mGluR1a mutant. The decrease of mGluR1a resulted from accelerated protein turnover, as revealed by pulse–chase experiments. The Siah1A-mediated degradation of group 1 mGluRs was abrogated by not only mutations at the RING-finger domain of Siah1A but also treatment with a proteasome inhibitor. Siah1A coexpression induced strong ubiquitination of group 1 mGluRs. Replacements of lysine residues with arginine showed that Siah1A-mediated ubiquitination occurs at multiple lysine residues spanning both the seven-transmembrane region and carboxyl-terminal tail of mGluR5.In situhybridization histochemistry showed a wide-spread distribution of Siah1 mRNAs, with high expression in the hippocampal pyramidal neurons and cerebellar Purkinje cells. Group 1 mGluRs play critical roles in the neural plasticity in both the hippocampal neurons and Purkinje cells. This investigation indicates that Siah1A serves as a selective ubiquitin ligase that mediates ubiquitination-dependent degradation of long splice variants of group 1 mGluRs and would contribute to posttranslational down-regulation of group 1 mGluRs.
Biological control of sciarid and phorid pests of mushroom with predatory mites from the genusHypoaspis(Acari: Hypoaspidae) and the entomopathogenic nematodeSteinernema feltiae
Authors: Jess S. , Bingham J.F.W.
Published: May 2004

In small-scale experiments, the predatory mites,Hypoaspis aculeifer(Canestrini) andH. milesBerlese, applied at 700 mites m−2, and the entomopathogenic nematode,Steinernema feltiae(Filipjev) applied at 3 × 10−6nematodes m−2controlled sciarids and phorids in mushroom compost and casing substrates. For both mite species, earliest application to the growing substrate following sciarid infestation reduced sciarid emergence. In contrast, later application of each biological control agent provided more effective control of phorid emergence. The behaviour of adult mites suggested thatH. aculeiferwere more positively geotactic thanH. milesalthough both species could penetrate compost and casing substrates to a depth of 2–12 cm. A majority ofS. feltiaenematodes resided at a depth of 2–4 cm in both substrate types. Independent application ofH. aculeiferprovided more comprehensive control of sciarids and phorids than the other biological agents studied, owing to its better dispersal within compost and casing, and ability to attack larvae of differing ages.
Nectar-related vs. human-related volatiles: behavioural response and choice by female and male Anopheles gambiae (Diptera: Culicidae) between emergence and first feeding
Authors: Foster W.A. , Takken W.
Published: May 2004

The close association of Anopheles gambiae Giles with humans and its females’ ability to live on human blood alone suggest that females may ignore sources of sugar in favour of human blood as a source of energy. They have limited energy reserves at emergence, and at 27°C both sexes generally die if they do not feed during night 1, 24–36 h after emergence. Food preferences during this critical period were tested by measuring responses to volatiles from honey and soiled socks, which served as surrogates for nectar-related and human-related volatiles in a wind-tunnel olfactometer. Both sexes responded more strongly to honey than to human volatiles, and given a choice, preferred honey over human volatiles. After 5 days of sugar access and maturation, males continued to prefer honey volatiles, whereas females changed behaviour, responding almost exclusively to human volatiles. Night 1 experiments also demonstrated that: (i) females previously having had sugar during the night of emergence responded more strongly to human volatiles; (ii) large-bodied mosquitoes of both sexes responded more strongly to honey than small-bodied ones; and (iii) females were equally responsive to honey in both early and late scotophase but were slightly more responsive to human volatiles in late scotophase. These results indicate that for a female’s first meal, sugar is a viable option and is preferred when nectar-related stimuli are strong. This supports field evidence that sugar-feeding is a significant component of A. gambiae female behaviour.
Teaching and learning speech and language therapy skills: the effectiveness of classroom as clinic in speech and language therapy student education
Authors: Horton S. , Byng S. , Bunning K. , Pring T.
Published: May 2004

Background: Terms such as ‘clinical intuition’ have often been applied to the practice of speech and language therapy. Various authors have aimed to make the process of therapy practice more explicit, and it is argued that recently developed descriptive/analytic frameworks have the potential to engender the critical mindset necessary for student speech and language therapists to become good reflective practitioners, with the potential for enhancing clinical education.

Aims: To investigate whether and how aspects of clinical skills education could be usefully addressed in an academic, as opposed to a clinical, setting. The study aimed to address the question of whether use of an interaction analysis system, in conjunction with video observation, and ‘practice simulation’ in a teaching–learning programme could be shown to have a positive impact on: (1) students' perceptions of their own understanding and practice of therapy, and their perceptions of themselves as self‐reflective practitioners; and whether (2) this was borne out by students' ability to observe and interpret therapeutic interaction, as measured by (i) an objective written assessment; (ii) an objective video observation assessment; and (iii) assessment of their abilities in clinical practice.

Methods & Procedures: Thirty‐six students from City University took part in an experimental, placebo‐controlled study using a deferred intervention design. Assessments designed to reflect changes resulting from the teaching–learning curriculum were carried out pre‐ and post‐intervention with experimental and control groups. Quantitative and qualitative results were obtained.

Outcomes & Results: The intervention programme was found to have had a significant impact on students' perceptions of their understanding of therapy, but not on their perceptions of their practice of therapy. The experimental group scored significantly better on a written assessment of ‘interpretation of therapy interaction’, but were no better than the control group on a ‘Video observation’ assessment. Owing to attrition and the poor quality of videos submitted for assessment, it was not possible to measure changes in actual clinical practice. Qualitative feedback from the teaching–learning programme suggests that students generally found the approach to be beneficial.

Conclusions: While there were some encouraging results, it is still uncertain whether addressing the actual practice of therapy in an academic setting gives ‘added value’ to the work carried out on clinical placements. However, there is no doubt that bringing this type of programme under the umbrella of an academic institution would greatly increase the consistency of teaching and the range of experiences available to students.
Realizability of modules over Tate cohomology
Authors: Benson David , Krause Henning , Schwede Stefan
Published: May 2004

Letkkbe a field and letGGbe a finite group. There is a canonical element in the Hochschild cohomology of the Tate cohomologyγG∈HH3,−1H^∗(G,k)\gamma _G\in H\!H^{3,-1}\hat H^*(G,k)with the following property. Given a gradedH^∗(G,k)\hat H^*(G,k)-moduleXX, the image ofγG\gamma _Gin<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper E x t Subscript ModifyingAbove upper H With caret Sub Superscript asterisk Subscript left-parenthesis upper G comma k right-parenthesis Superscript 3 comma negative 1 Baseline left-parenthesis upper X comma upper X right-parenthesis">ExtH^∗(G,k)3,−1⁡(X,X)\operatorname {Ext}^{3,-1}_{\hat H^*(G,k)}(X,X)vanishes if and only ifXXis isomorphic to a direct summand ofH^∗(G,M)\hat H^*(G,M)for somekGkG-moduleMM. The description of the realizability obstruction works in any triangulated category with direct sums. We show that in the case of the derived category of a differential graded algebraAA, there is also a canonical element of Hochschild cohomologyHH3,−1H∗(A)H\!H^{3,-1}H^*(A)which is a predecessor for these obstructions.
Parabolic evolution equations with asymptotically autonomous delay
Authors: Schnaubelt Roland
Published: May 2004

We study retarded parabolic non-autonomous evolution equations whose coefficients converge as

t
→
∞

t\to \infty

, such that the autonomous problem in the limit has an exponential dichotomy. Then the non-autonomous problem inherits the exponential dichotomy, and the solution of the inhomogeneous equation tends to the stationary solution at infinity. We use a generalized characteristic equation to deduce the exponential dichotomy and new representation formulas for the solution of the inhomogeneous equation.
An extended urn model with application to approximation
Authors: Chen Fengxin
Published: May 2004

Pólya’s urn model from probability theory is extended to obtain a class of approximation operators for which the Weierstrass Approximation Theorem holds.
Ideals in a perfect closure, linear growth of primary decompositions, and tight closure
Authors: Sharp Rodney , Nossem Nicole
Published: May 2004

This paper is concerned with tight closure in a commutative Noetherian ring

R
R

of prime characteristic

p
p

, and is motivated by an argument of K. E. Smith and I. Swanson that shows that, if the sequence of Frobenius powers of a proper ideal

a

{\mathfrak {a}}

of

R
R

has linear growth of primary decompositions, then tight closure (of

a

{\mathfrak {a}}

) ‘commutes with localization at the powers of a single element’. It is shown in this paper that, provided

R
R

has a weak test element, linear growth of primary decompositions for other sequences of ideals of

R
R

that approximate, in a certain sense, the sequence of Frobenius powers of

a

{\mathfrak {a}}

would not only be just as good in this context, but, in the presence of a certain additional finiteness property, would actually imply that tight closure (of

a

{\mathfrak {a}}

) commutes with localization at an arbitrary multiplicatively closed subset of

R
R

. Work of M. Katzman on the localization problem for tight closure raised the question as to whether the union of the associated primes of the tight closures of the Frobenius powers of

a

{\mathfrak {a}}

has only finitely many maximal members. This paper develops, through a careful analysis of the ideal theory of the perfect closure of

R
R

, strategies for showing that tight closure (of a specified ideal

a

{\mathfrak {a}}

of

R
R

) commutes with localization at an arbitrary multiplicatively closed subset of

R
R

and for showing that the union of the associated primes of the tight closures of the Frobenius powers of

a

{\mathfrak {a}}

is actually a finite set. Several applications of the strategies are presented; in most of them it was already known that tight closure commutes with localization, but the resulting affirmative answers to Katzman’s question in the various situations considered are believed to be new.
A class of processes on the path space over a compact Riemannian manifold with unbounded diffusion
Authors: Löbus Jörg-Uwe
Published: May 2004

A class of diffusion processes on the path space over a compact Riemannian manifold is constructed. The diffusion of such a process is governed by an unbounded operator. A representation of the associated generator is derived and the existence of a certain local second moment is shown.
Jack polynomials and some identities for partitions
Authors: Lassalle Michel
Published: May 2004

We prove an identity about partitions involving new combinatorial coefficients. The proof given is using a generating function. As an application we obtain the explicit expression of two shifted symmetric functions, related with Jack polynomials. These quantities are the moments of the “α\alpha-content” random variable with respect to some transition probability distributions.
Enhanced oncogenicity of Asian-American human papillomavirus 16 is associated with impaired E2 repression of E6/E7 oncogene transcription
Authors: Ordóñez Rosa M. , Espinosa Ana María , Sánchez-González Dolores Javier , Armendáriz-Borunda Juan , Berumen Jaime
Published: May 2004

Asian-American (AA) variants of human papillomavirus 16 (HPV-16) are linked to a high incidence of cervical cancer in Mexico, with some evidence strongly suggesting that they are more oncogenic than European (E) variants, including their association with younger women and their higher associated risk of cervical cancer. Differences in the regulation of viral E6/E7 oncogene transcription by the E2 protein may be involved in the higher oncogenicity of AA variants. In E variants, E6/E7 oncogene transcription is repressed by the E2 protein and is frequently up-regulated by the destruction of the E2 gene during viral integration. In contrast, the E2 gene is retained in full in most AA-positive carcinomas, raising the possibility of alternative mechanisms for increasing viral oncogene transcription. The authors investigated whether the higher oncogenicity of AA variants is linked to differences in E6/E7 oncogene transcription and the mechanism of E2 deactivation. E6/E7 and E1/E2 transcripts were explored by RT-PCR in 53 HPV-16-positive cervical carcinomas, 39 retaining (20 European and 19 AA) and 14 having lost (12 European and 2 AA) the E1/E2 genes, and transcription repression activity of the AA E2 genes was tested in four cell lines that constitutively express the β-galactosidase reporter or E6/E7 genes driven by the viral long control region. E6/E7 oncogene transcripts were found in all carcinomas, but only those positive for AA variants with E1/E2 genes had complete E2 transcripts. E2 transcripts were down-regulated by splicing in E-positive carcinomas retaining E1/E2. AA E2 genes were impaired for repression of E6/E7 oncogene transcription in vivo. These results suggest that E6/E7 oncogene expression starts earlier in AA than E variant infections, since E variants need E2 to be destroyed or down-regulated.
Poliovirus binding to its receptor in lipid bilayers results in particle-specific, temperature-sensitive channels
Authors: Tosteson Magdalena T. , Wang Hong , Naumov Anatoli , Chow Marie
Published: May 2004

Poliovirus (PV) infection starts with binding to its receptor (PVR), followed by a receptor-aided, temperature-sensitive conformational change of the infectious particle (sedimenting at 160S) to a particle which sediments at 135S. Reported in this communication is the successful incorporation into lipid bilayers of two forms of the receptor: the full-length human receptor and a modified clone in which the extracellular domains of the receptor were fused to a glycosylphosphatidylinositol tail. Addition of virus (160S) to receptor-containing bilayers leads to channel formation, whereas no channels were observed when the receptor-modified viral particle (135S) was added. Increasing the temperature from 21 to 31 °C led to a 10-fold increase in the magnitude of the single channel conductance, which can be interpreted as a conformational change in the channel structure. A mutant PV with an amino acid change in VP4 (one of the coat proteins) which is defective in genome uncoating failed to produce channels, suggesting that VP4 might be involved in the channel architecture. These studies provide the first electrophysiological characterization of the interactions between poliovirus and its receptor incorporated into a lipid bilayer membrane. Furthermore, they form the foundation for future studies aiming at defining the molecular architecture of the virus–receptor complex.
Amyloid imaging probes are useful for detection of prion plaques and treatment of transmissible spongiform encephalopathies
Authors: Ishikawa Kensuke , Doh-ura Katsumi , Kudo Yukitsuka , Nishida Noriyuki , Murakami-Kubo Ikuko , Ando Yukio , Sawada Tohru , Iwaki Toru
Published: May 2004

Diagnostic imaging probes have been developed to monitor cerebral amyloid lesions in patients with neurodegenerative disorders. A thioflavin derivative, 2-[4′-(methylamino)phenyl] benzothiazole (BTA-1) and a Congo red derivative, (trans, trans),-1-bromo-2,5-bis-(3-hydroxycarbonyl-4-hydroxy)styrylbenzene (BSB) are representative chemicals of these probes. In this report, the two chemicals were studied in transmissible spongiform encephalopathies (TSE). Both BTA-1 and BSB selectively bound to compact plaques of prion protein (PrP), not only in the brain specimens of certain types of human TSE, but also in the brains of TSE-infected mice when the probes were injected intravenously. The chemicals bound to plaques in the brains were stable and could be detected for more than 42 h post-injection. In addition, the chemicals inhibited abnormal PrP formation in a cellular model of TSE with IC50 values of 4 nM for BTA-1 and 1·4 μM for BSB. In an experimental mouse model, the intravenous injection of 1 mg BSB prolonged the incubation period by 14 %. This efficacy was only observed against the RML strain and not the other strains examined. These observations suggest that these chemicals bind directly to PrP aggregates and inhibit new formation of abnormal PrP in a strain-dependent manner. Both BTA-1 and BSB can be expected to be lead chemicals not only for imaging probes but also for therapeutic drugs for TSEs caused by certain strains.
Single-nucleotide polymorphisms in two Marek's disease virus genes (Meq and gD): application to a retrospective molecular epidemiology study (1982–1999) in France
Authors: Laurent S. , Esnault E. , Rasschaert D.
Published: May 2004

Marek's disease virus (MDV) is a herpesvirus that causes a lymphoproliferative disease in chickens. Vaccines against MDV are available, but the virus is gradually becoming more virulent. A molecular epidemiology study of MDV was carried out by assessing nucleotide variation in two different genes, Meq and gD, in 68 French field isolates circulating from 1982 to 1999, compared with reference strains. Viral DNA was amplified by nested PCR and sequenced directly. Comparison of the nucleotide sequences revealed a high nucleotide sequence identity (98 %). Single-nucleotide polymorphisms were identified, leading to the identification of three gene alleles for gD and six for Meq. Nine combinations of alleles were identified. A majority of French isolates (60·5 %) clustered in the C1 type, which has been present for over 17 years. Waves of non-C1-type isolates appeared when vaccine efficacy decreased. Furthermore, specific discriminating sequences were obtained for the CVI-988 vaccine strain.
TT virus-derived apoptosis-inducing protein induces apoptosis preferentially in hepatocellular carcinoma-derived cells
Authors: Kooistra Klaas , Zhang Ying-Hui , Henriquez Niek V. , Weiss Bertram , Mumberg Dominik , Noteborn Mathieu H. M.
Published: May 2004

TT virus (TTV) is widespread among the global population. Its pathogenic nature is still unclear but TTV seems to be more prevalent in cases of hepatitis than in healthy individuals. TTV harbours similarities to chicken anaemia virus (CAV). Here, the apoptotic potential of a putative TTV-derived 105 aa protein and of the main apoptosis-inducing agent of CAV, Apoptin, is compared. As the putative protein induced apoptosis in various human hepatocellular carcinoma (HCC) cell lines, it was named TTV-derived apoptosis-inducing protein (TAIP). The apoptotic activity of TAIP in HCC lines was comparable with that of Apoptin. Conversely, unlike Apoptin, TAIP induced only low-level apoptosis in several non-HCC human cancer cell lines. The data suggest that TAIP acts in a different way to Apoptin as it is selective to a certain degree for HCC lines. This activity of TAIP, coupled with the heterogeneity of TTV isolates, may help to explain the variable reports of TTV pathogenicity.