bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase behavior of the base‐catalyzed transesterification of soybean oil
Authors: Zhou Weiyang , Boocock D. G. B.
Published: February 2007

Biodiesel is made by the transesterification of vegetable oils to form alkyl FA esters. High levels of conversion (>99%) are required to lower the total concentration of free and chemically bound glycerol to that allowed by the ASTM standard (0.240 wt%) for biodiesel. A polar dye was used to visualize the phase behaviors in methanolysis, ethanolysis, and butanolysis. The dye was more strongly colored in more polar phases. Methanolysis and ethanolysis reactions commenced as two phases (alcohol and oil), then formed emulsions, and ended as two phases as glycerol‐rich phases separated. Ethanolysis was more easily initiated by mixing than was methanolysis. Ethanolysis also exhibited a much longer emulsion period and slower glycerol separation. The glycerol‐rich phase was smaller in volume in ethanolysis than in methanolysis. Butanolysis remained one phase throughout, and no polar phase existed at any time. The results are consistent with the known phase compositions in these reactions. The concentrations of MG, DG, and TG in the products with time in stirred reactions were consistent with the observed phase behavior in the dye experiments.
Acoustic shock
Authors: McFerran D J , Baguley D M
Published: February 2007

Acoustic shock is a recently recognised clinical entity: following an abrupt, intense and unanticipated acoustic stimulus, usually delivered by a telephone handset or headset, some individuals report a symptom cluster that includes otalgia, altered hearing, aural fullness, imbalance, tinnitus, dislike or even fear of loud noises, and anxiety and/or depression. Symptoms start shortly after the triggering acoustic incident and can be short-lived or can last for a considerable time. If persistent, the condition can lead to significant disability. Proposed mechanisms include involvement of the tensor tympani muscle, hyperexcitability of central auditory pathways, and a precursive state of raised anxiety or arousal. A formal treatment programme has not yet been proposed, but the potential utility of modern therapeutic techniques for tinnitus and hyperacusis are considered. Given the large number of UK residents working in telephone call centres, this condition is of considerable clinical importance.
Age-dependent dynamics of Theileria equi and Babesia caballi infections in southwest Mongolia based on IFAT and/or PCR prevalence data from domestic horses and ticks
Authors: RÜEGG S. R. , TORGERSON P. , DEPLAZES P. , MATHIS A.
Published: February 2007

Epidemiological factors of tick-borne equine piroplasmoses, caused by Theileria equi and Babesia caballi, were investigated using logistic regression (GLM) and general additive models (GAM) based on the prevalences determined in 510 domestic horses and in ticks in S.W. Mongolia by indirect immunofluorescence antibody test (IFAT) and/or multiplex PCR. Prevalences of T. equi and B. caballi in horses were 66·5% (95% CI: 62·1–70·7) and 19·1% (15·6–22·9), respectively by PCR and 78·8% (74·9–82·3) and 65·7% (61·3–69·9) by IFAT. Of 166 ticks analysed from PCR- and IFAT-negative horses 1 was PCR positive for B. caballi and none for T. equi. GAM demonstrated non-linear increasing proportions of T. equi-PCR and -IFAT positive horses with age suggesting persistent infection. In contrast, the B. caballi-PCR prevalence decreased with age despite a concurrent increase in the proportion of IFAT-positive animals suggesting parasite elimination. The tick (Dermacentor nuttalli) burden of the horses increased with age and decreased with advancing season. Geldings were more likely to be infected with, and seroconvert to, T. equi. Neither herd affiliation, date of sample collection nor abundance of tick infestation had a significant influence on parasite prevalence.
Molecular typing ofStreptococcus pyogenesfrom remote Aboriginal communities where rheumatic fever is common and pyoderma is the predominant streptococcal infection
Authors: McDONALD M. I. , TOWERS R. J. , FAGAN P. , CARAPETIS J. R. , CURRIE B. J.
Published: February 2007

Aboriginal Australians in remote communities have high rates of rheumatic heart disease (RHD); yet pharyngitis is reportedly rare whilst pyoderma is common. Some strains of group A streptococci (GAS) have preference for the throat and others for the skin depending on M protein type. A study in three remote communities provided 350 GAS isolates foremmsequence typing, 244 were alsoemmpattern typed. There was 100% correlation betweenemmsequence and pattern type. Patterns D and E (non-throat tropic) made up 71% of throat and 87% of skin isolates although patterns A–C (throat tropic) were more common in the throat than the skin (RR 2·3, 95% CI 1·4–3·8) whilst the opposite was found for pattern D (RR 2·2, 95% CI 1·7–3·0). Pattern E favoured the throat (RR 1·4, 95% CI 1·1–1·8). Where environmental factors predispose to skin infection,emmpattern types D and E prevail, whatever the recovery site.
The impact of a school-based safe water and hygiene programme on knowledge and practices of students and their parents: Nyanza Province, western Kenya, 2006
Authors: O'REILLY C. E. , FREEMAN M. C. , RAVANI M. , MIGELE J. , MWAKI A. , AYALO M. , OMBEKI S. , HOEKSTRA R. M. , QUICK R.
Published: February 2007

Safe drinking water and hygiene are essential to reducing Kenya's diarrhoeal disease burden. A school-based safe water and hygiene intervention in Kenya was evaluated to assess its impact on students' knowledge and parents' adoption of safe water and hygiene practices. We surveyed 390 students from nine schools and their parents at baseline and conducted a final evaluation of 363 students and their parents. From baseline to final evaluation, improvement was seen in students' knowledge of correct water treatment procedure (21–65%,P<0·01) and knowing when to wash their hands. At final evaluation, 14% of parents reported currently treating their water, compared with 6% at baseline (P<0·01). From 2004 to 2005, school absenteeism in the September–November term decreased in nine project schools by 35% and increased in nine neighbouring comparison schools by 5%. This novel programme shows promise for reducing school absenteeism and promoting water and hygiene interventions in the home.
Changes in carotenoid intake from fruit and vegetables in the Spanish population over the period 1964–2004
Authors: Granado F , Blázquez S , Olmedilla B
Published: February 2007

Objective

To assess changes in carotenoid intake based on the variations in the consumption of fresh fruit and vegetables in the Spanish population over the period 1964–2004.

Design

Consumption data of fresh fruit and vegetables from Family Budget Surveys carried out in 1964, 1980, 1990 and 2004. Consumption data (g per person per day) accounted for >90% of fruit and vegetable consumption at each time point. Quality controlled high-performance liquid chromatography analysis of the carotenoid composition of Spanish fruit and vegetable was used.

Subjects

Randomly selected, private households throughout Spain (20 800 households in 1964, 30 311 households in 1980, 21 155 households in 1990 and 6000 households in 2004). Twelve vegetables and 16 fruits representing 89–96% of the total consumption of fresh fruit and vegetables were used.

Results

Individual consumption of fruit and vegetables has changed over this period, altering the total and individual intake of carotenoids. Total carotenoid intake increased from 2.5 mg per person per day in 1964 to 4.1 mg per person per day in 1990, with a decrease to 3.3 mg per person per day in 2004. These increments are due to an increase in lycopene, α- and β-carotene, while a decrease in lutein and zeaxanthin is observed during the last decade. A continuous and consistent decrease in the relative contribution of lutein in the diet is observed over the period studied.

Conclusion

Although the consumption of fruit and vegetables is still consistent with a Mediterranean-type pattern, modifications in the consumption of individual fruits and vegetables have provoked changes in total and specific carotenoid intake with potential relevance in human health.
The detection of organic matter in terrestrial snow and ice: implications for astrobiology
Authors: Phillips S.J.M. , Parnell J.
Published: February 2007

The discovery of icy bodies in our Solar System has opened up the possibility that life may exist on and below their surfaces. Snow and ice are good sites for the preservation of biomarkers as they trap and preserve organic matter that is deposited onto their surfaces. Terrestrial samples of snow and ice collected from Ben Macdui in north east Scotland have been analysed for organic compounds contained within them. A range of n-alkanes and n-alkanoic acids were found in both samples. The particulate matter contained proportionally more higher weight n-alkanols than the melted water. This is because higher molecular weight molecules are less soluble in water. Therefore, the volume of snow and ice to be sampled on other icy bodies is an important factor, as many important biomarkers have high molecular weights and may not be detected in small quantities of melted water.
Developmental Fractionation of Working Memory and Response Inhibition During Childhood
Authors: Tsujimoto Satoshi , Kuwajima Mariko , Sawaguchi Toshiyuki
Published: February 2007

Abstract. The lateral prefrontal cortex (LPFC) plays a major role in both working memory (WM) and response inhibition (RI), which are fundamental for various cognitive abilities. We explored the relationship between these LPFC functions during childhood development by examining the performance of two groups of children in visuospatial and auditory WM tasks and a go/no-go RI task. In the younger children (59 5- and 6-year-olds), performance on the visuospatial WM task correlated significantly with that in the auditory WM task. Furthermore, accuracy in these tasks correlated significantly with performance on the RI task, particularly in the no-go trials. In contrast, there were no significant correlations among those tasks in older children (92 8- and 9-year-olds). These results suggest that functional neural systems for visuospatial WM, auditory WM, and RI, especially those in the LPFC, become fractionated during childhood, thereby enabling more efficient processing of these critical cognitive functions.
False Memory in a Short-Term Memory Task
Authors: Coane Jennifer H. , McBride Dawn M. , Raulerson III Bascom A. , Jordan J. Scott
Published: February 2007

The Deese/Roediger-McDermott (DRM; Roediger & McDermott, 1995 ) paradigm reliably elicits false memories for critical nonpresented words in recognition tasks. The present studies used a Sternberg (1966) task with DRM lists to determine whether false memories occur in short-term memory tasks and to assess the contribution of latency data in the measurement of false memories. Subjects studied three, five, or seven items from DRM lists and responded to a single probe (studied or nonstudied). In both experiments, critical lures were falsely recognized more often than nonpresented weak associates. Latency data indicated that correct rejections of critical lures were slower than correct rejections of weakly related items at all set sizes. False alarms to critical lures were slower than hits to list items. Latency data can distinguish veridical and false memories in a short-term memory task. Results are discussed in terms of activation-monitoring models of false memory.
Statistical and dynamical downscaling of precipitation: An evaluation and comparison of scenarios for the European Alps
Authors: Schmidli J. , Goodess C. M. , Frei C. , Haylock M. R. , Hundecha Y. , Ribalaygua J. , Schmith T.
Published: February 2007

This paper compares six statistical downscaling models (SDMs) and three regional climate models (RCMs) in their ability to downscale daily precipitation statistics in a region of complex topography. The six SDMs include regression methods, weather typing methods, a conditional weather generator, and a bias correction and spatial disaggregation approach. The comparison is carried out over the European Alps for current and future (2071–2100) climate. The evaluation of simulated precipitation for the current climate shows that the SDMs and RCMs tend to have similar biases but that they differ with respect to interannual variations. The SDMs strongly underestimate the magnitude of the year‐to‐year variations. Clear differences emerge also with respect to the year‐to‐year anomaly correlation skill: In winter, over complex terrain, the better RCMs achieve significantly higher skills than the SDMs. Over flat terrain and in summer, the differences are smaller. Scenario results using A2 emissions show that in winter mean precipitation tends to increase north of about 45°N and insignificant or opposite changes are found to the south. There is good agreement between the downscaling models for most precipitation statistics. In summer, there is still good qualitative agreement between the RCMs but large differences between the SDMs and between the SDMs and the RCMs. According to the RCMs, there is a strong trend toward drier conditions including longer periods of drought. The SDMs, on the other hand, show mostly nonsignificant or even opposite changes. Overall, the present analysis suggests that downscaling does significantly contribute to the uncertainty in regional climate scenarios, especially for the summer precipitation climate.
Effects of soil freezing and thawing on vegetation carbon density in Siberia: A modeling analysis with the Lund‐Potsdam‐Jena Dynamic Global Vegetation Model (LPJ‐DGVM)
Authors: Beer C. , Lucht W. , Gerten D. , Thonicke K. , Schmullius C.
Published: February 2007

The current latitudinal gradient in biomass suggests a climate‐driven limitation of biomass in high latitudes. Understanding of the underlying processes, and quantification of their relative importance, is required to assess the potential carbon uptake of the biosphere in response to anticipated warming and related changes in tree growth and forest extent in these regions. We analyze the hydrological effects of thawing and freezing of soil on vegetation carbon density (VCD) in permafrost‐dominated regions of Siberia using a process‐based biogeochemistry‐biogeography model, the Lund‐Potsdam‐Jena Dynamic Global Vegetation Model (LPJ‐DGVM). The analysis is based on spatially explicit simulations of coupled daily thaw depth, site hydrology, vegetation distribution, and carbon fluxes influencing VCD subject to climate, soil texture, and atmospheric CO2 concentration. LPJ represents the observed high spring peak of runoff of large Arctic rivers, and simulates a realistic fire return interval of 100 to 200 years in Siberia. The simulated VCD changeover from taiga to tundra is comparable to inventory‐based information. Without the consideration of freeze‐thaw processes VCD would be overestimated by a factor of 2 in southern taiga to a factor of 5 in northern forest tundra, mainly because available soil water would be overestimated with major effects on fire occurrence and net primary productivity. This suggests that forest growth in high latitudes is not only limited by temperature, radiation, and nutrient availability but also by the availability of liquid soil water.
Impact of global dimming and brightening on global warming
Authors: Wild Martin , Ohmura Atsumu , Makowski Knut
Published: February 2007

Speculations on the impact of variations in surface solar radiation on global warming range from concerns that solar dimming has largely masked the full magnitude of greenhouse warming, to claims that the recent reversal from solar dimming to brightening rather than the greenhouse effect was responsible for the observed warming. To disentangle surface solar and greenhouse influences on global warming, trends in diurnal temperature range are analyzed. They suggest that solar dimming was effective in masking greenhouse warming, but only up to the 1980s, when dimming gradually transformed into brightening. Since then, the uncovered greenhouse effect has revealed its full dimension, as manifested in a rapid temperature rise (+0.38°C/decade over land since mid‐1980s). Recent solar brightening cannot supersede the greenhouse effect as main cause of global warming, since land temperatures increased by 0.8°C from 1960 to 2000, even though solar brightening did not fully outweigh solar dimming within this period.
Waveform modeling of the slab beneath Japan
Authors: Chen Min , Tromp Jeroen , Helmberger Don , Kanamori Hiroo
Published: February 2007

The tomographic P wave model for the Japan subduction zone derived by Zhao et al. (1994) has two very striking features: a slab about 90 km thick with P wave velocities 3–6% higher than the surrounding mantle and a mantle wedge with −6% low‐velocity anomalies. We study three‐component seismograms from more than 600 Hi‐net stations produced by two earthquakes which occurred in the downgoing Pacific Plate at depths greater than 400 km. We simulate body wave propagation in the three‐dimensional (3‐D) P wave model using 2‐D finite difference (FDM) and 3‐D spectral element (SEM) methods. As measured by cross correlation between synthetics and data, the P wave model typically explains about half of the traveltime anomaly and some of the waveform complexity but fails to predict the extended SH wave train. In this study we take advantage of the densely distributed Hi‐net stations and use 2‐D FDM modeling to simulate the P‐SV and SH waveforms. Our 2‐D model suggests that a thin, elongated low‐velocity zone exists atop the slab, extending down to a depth of 300 km with an S wave velocity reduction of 14% if a thickness of 20 km is assumed. Further, 3‐D SEM simulations confirm that this model explains a strong secondary arrival which cannot easily be imaged with standard tomographic techniques. The low‐velocity layer could explain the relatively weak coupling associated with most subduction zones at shallow depths (<50 km), generally involving abundant volcanic activity and silent earthquakes, and it may also help to further our understanding of the water‐related phase transition of ultramafic rocks, and the nature of seismicity at intermediate depths (∼70–300 km).
Carbonaceous material in aerosol particles in the lower stratosphere and tropopause region
Authors: Murphy D. M. , Cziczo D. J. , Hudson P. K. , Thomson D. S.
Published: February 2007

The Particle Analysis by Laser Mass Spectrometry (PALMS) instrument has measured the composition of single particles in the lower stratosphere. The average fraction of carbonaceous material in the stratospheric particles decreased rapidly above the tropopause. The decrease in the average carbon content was mostly associated with a sharp increase in the bottom 2 km of the stratosphere in the frequency of fairly pure sulfate particles both with or without meteoric metals. The low potassium content of the fairly pure sulfate particles is used to show that they were formed in the stratosphere and were not tropospheric particles that had lost organics because of oxidation. Of the tropospheric carbonaceous‐sulfate particles found in the stratosphere, the mass spectra had similar patterns from the upper troposphere to the maximum altitude sampled, about 19 km. A reduction in the carbon to sulfate ratio in tropospheric particles was only apparent above about 440 K potential temperature. This implies that carbon compounds can remain for months in particles larger than about 300 nm. Despite the slow rate, these data do not exclude rapid heterogeneous reactions of organics in the particles with OH or other radicals. There was no evidence of significant transfer of semivolatile organics between particles in the stratosphere. However, particles that originated in the stratosphere acquired small amounts of carbon when they were transported to the tropopause.
A robust geostatistical approach to contaminant source identification
Authors: Sun Alexander Y.
Published: February 2007

Estimation under model uncertainty remains a practical concern in many scientific and engineering fields. A commonly encountered example in groundwater remediation is the contaminant source identification problem. Like many other inverse problems, contaminant source identification is inherently ill posed and is sensitive to both data and model uncertainties. Model uncertainties, which may be introduced at virtually any stage of a model building process, can adversely affect estimator performance if they are not accounted for properly. In this paper, a robust geostatistical approach (RGS), which is extended from the geostatistical inversion approach (GS), is used to solve linear estimation problems. The uncertainties in both model and covariance matrices are taken into account in the RGS formulation. The nominal correlation structural parameters are estimated using a structural analysis procedure. The resulting minimax optimization problem is solved using semidefinite programming techniques. The RGS is generic and can be applied to any problem for which the GS is suitable and the upper bound of uncertainty can be quantified. The RGS is illustrated for source release history identification in a two‐dimensional aquifer where the model uncertainty is caused by variability in hydraulic conductivity. It is shown that when the model is perfectly known, the RGS solution coincides with that of the GS; when the model has uncertainty, the RGS is robust against unknown variations from a nominal model, and its overall performance is better than that of the GS using the same nominal model.
sl
(
2
,
R
)
symmetry and solvable multiboson systems
Authors: Goliński Tomasz , Horowski Maciej , Odzijewicz Anatol , Sliżewska Aneta
Published: February 2007

The one-mode and the two-mode multiboson systems with sl(2,R) symmetry are investigated. Hamiltonians of these systems are integrated using the theory of orthogonal polynomials. The coherent state representation for these systems is constructed.
Fatigue suppression of ferroelectric Pb1−xBax(Zr0.52Ti0.48)O3 thin films prepared by sol-gel method
Authors: Wang Y. , Wang K. F. , Zhu C. , Wei T. , Zhu J. S. , Liu J.-M.
Published: February 2007

The polarization fatigue behavior of ferroelectric Pb1−xBax(Zr0.52Ti0.48)O3 (PBZT) thin films deposited on Pt-coated silicon wafers by sol-gel method is investigated. The fatigue endurance is significantly enhanced upon Ba doping and almost fatigue-free performance up to 1010 switching cycles for PBZT (x=0.1) thin films are observed at room temperature. It is revealed that Ba doping up to x=0.1 results in a 70% decrease of oxygen vacancies in the films. The improved fatigue endurance is attributed to the enhanced oxygen ion stability and suppressed oxygen vacancies.
Dynamic and steady state current response to light excitation of multilayered organic photodiodes
Authors: Zaus E. S. , Tedde S. , Fürst J. , Henseler D. , Döhler G. H.
Published: February 2007

Measurements of current transients are used to gain insight into the mechanism of charge transport and extraction of photodiodes based on bulk heterojunction blends of poly-3-hexyl-thiophene and [6,6]-phenyl C61 butyric acid methyl ester. It is shown that the implementation of an appropriate hole conducting layer leads to a reduction of the dark current in the reverse direction. It is observed that the dynamic response to light excitation is strongly influenced by the thickness of the hole conducting layer, the light intensity, and the applied bias. Charge accumulation at the interface is assumed to result in the characteristic shape of the transients. The shape of the switch-off transient can be understood qualitatively by an equivalent circuit diagram.
Structural and elastic characterization of Cu-implanted SiO2 films on Si(100) substrates
Authors: Shirokoff J. , Young C. K. , Brits L. C. , Andrews G. T. , Johannessen B. , Ridgway M. C.
Published: February 2007

Cu-implanted SiO2 films on Si(100) have been studied and compared to unimplanted SiO2 on Si(100) using x-ray methods, transmission electron microscopy, Rutherford backscattering, and Brillouin spectroscopy. The x-ray results indicate the preferred orientation of Cu {111} planes parallel to the Si substrate surface without any directional orientation for Cu-implanted SiO2∕Si(100) and for Cu-implanted and annealed SiO2∕Si(100). In the latter case, transmission electron microscopy reveals the presence of spherical nanocrystallites with an average size of ∼2.5 nm. Rutherford backscattering shows that these crystallites (and the Cu in the as-implanted film) are largely confined to depths of 0.4−1.2 μm below the film surface. Brillouin spectra contain peaks due to surface, film-guided and bulk acoustic modes. Surface (longitudinal) acoustic wave velocities for the implanted films were ∼7% lower (∼2% higher) than for unimplanted SiO2∕Si(100). Elastic constants were estimated from the acoustic wave velocities and film densities. C11 (C44) for the implanted films was ∼10% higher (lower) than that for the unimplanted film. The differences in acoustic velocities and elastic moduli are ascribed to implantation-induced compaction and/or the presence of Cu in the SiO2 film.
Effect of bulk inversion asymmetry on optical transitions of zinc blende semiconductor quantum wells
Authors: Chen Chun-Nan , Chang Sheng-Hsiung , Lee Meng-En , Chiang Jih-Chen , Lo Ikai , Wang Wan-Tsang , Gau Ming-Hong , Kao Hsiu-Fen
Published: February 2007

The influence of bulk inversion asymmetry (tetrahedral) on the optical transitions in zinc blende quantum wells is analyzed using an enhanced k∙p optical calculation framework which takes intracell interactions into account. It is shown that inversion asymmetry results in a marked variation of the optical transition strength. Significantly, this effect cannot be revealed by the conventional k∙p optical transition formalism, which considers intercell interactions only.
Re-Urbanity: Urbanising the Rural and Ruralising the Urban
Authors: Lacour Claude , Puissant Sylvette
Published: February 2007

In recent years, increased attention has been paid to intermediate zones, especially medium-sized and small-sized areas, which have witnessed new sociospatial dynamics. We discuss a theoretical approach for updating the analysis of the structuring and the functioning of these areas which are searching for an identity. We assume, in particular, that they would express a new spatial model, which is qualified as re-urbanity. We present our arguments by combining rural and urban features and values, enabling us to constitute a comprehensive framework for these emergent sociospatial dynamics.
Residential Location and the Biophysical Environment: Exurban Development Agents in a Heterogeneous Landscape
Authors: Yin Li , Muller Brian
Published: February 2007

Agent-based models offer a promising framework for analyzing interactions between agents and a heterogeneous landscape. Researchers have identified a complex of factors that influence exurban development, including demographic shifts and location attractiveness of natural amenities as a magnet to amenity-seeking migrants. Attractiveness is often defined in terms of local or on-lot amenities, including scenic views, the availability of natural features, and low levels of noise. However, exurban-growth models have not fully incorporated a fundamental insight of this literature, that the location behavior of exurban residents is sensitive to fine-grained variations in their biophysical environment. In this study we evaluate how agents and households operate in exurban environments and respond to biophysical features. We simulate household decisionmaking in terms of preferences for features such as site accessibility, two-dimensional amenities, and three-dimensional scenic views. Our results show that, as we build two-dimensional and three-dimensional landscape layers, our model captures the characteristics of landscape change with increasing accuracy. This approach has considerable potential to improve our ability to describe development dynamics in heterogeneous land markets.
Long-term forest landscape responses to fire exclusion in the Great Xing'an Mountains, China
Authors: Chang Yu , He Hong S. , Bishop Ian , Hu Yuanman , Bu Rencang , Xu Chonggang , Li Xiuzhen
Published: February 2007

Understanding of long-term forest landscape dynamics under fire exclusion, which have not been studied in north-eastern China, is increasingly needed for designing sound forest management and protection plans. In the present study, we examine whether long-term fire exclusion leads to catastrophic fires and whether the fire regimes altered by fire exclusion have changed the course of natural succession of dominant tree species. We designed two simulation scenarios – fire exclusion and no fire exclusion – and used LANDIS to study the long-term (300 years) fire regime dynamic and the succession of dominant tree species in terms of species abundance, age structure and spatial pattern. Our simulated results show that fire exclusion can lead to catastrophic fires with return intervals ranging from 50 to 120 years, increase the proportion of coniferous forests and decrease the proportion of deciduous forests, simplify tree species composition, and alter forest age structures and landscape patterns. Based on these simulated results, we suggest that prescribed burning or coarse woody debris reduction, uneven age management, and a comprehensive wildlife habitat suitability analysis should be incorporated in forest management plans in this region.
Fluctuations in fuel moisture across restoration treatments in semi-arid ponderosa pine forests of northern Arizona, USA
Authors: Faiella Shawn Michael , Bailey John Duff
Published: February 2007

Fuel moisture is an important variable in estimating fire behaviour and wildfire hazard. We measured three replicates each of thin-and-burn, burn-only, and control treatments in semi-arid ponderosa pine forests of northern Arizona, USA to quantify temporal changes and treatment effects on live foliar and dead fuel moisture content. Overstorey structure and canopy bulk density were reduced 40–75% in the thin-and-burn treatment v. the burn-only and control treatments. Fluctuations in foliar moisture content varied temporally and across study areas. In 2003, a significant treatment effect was found for two study sites for 1-year-old foliage, but no significant treatment effect was found for new foliage. In 2004, a significant treatment effect was found across all three study sites for both 1-year-old and new foliage. However, no clear pattern existed regarding a specific treatment and its effect on moisture content of old or new foliage. No conclusive evidence was found for a significant treatment effect on the moisture content of fuel particles in the size classes of 0–6, 6–25, and 25–100-mm diameter. Proposals regarding amplified fire behaviour as a consequence of reduced fuel moisture contents in treated v. untreated forest stands in semi-arid ponderosa pine forests of northern Arizona therefore appear to be unwarranted.
Th1/Th2 cross-regulation and the discovery of IL-10
Authors: Bashyam Hema
Published: February 2007

In the late 1980s, Tim Mosmann and colleagues isolated functionally distinct T helper (Th)-1 and Th2 clones, and provided evidence that these two subsets were mutually inhibitory. Knowledge of the inhibition led to the discovery that Th2 cells make IL-10 to suppress Th1 cells.
ClusterDraw web server: a tool to identify and visualize clusters of binding motifs for transcription factors
Authors: Papatsenko Dmitri
Published: February 2007

ClusterDraw is a program aimed to identification of binding sites and binding-site clusters. Major difference of the ClusterDraw from existing tools is its ability to scan a wide range of parameter values and weigh statistical significance of all possible clusters, smaller than a selected size. The program produces graphs along with decorated FASTA files. ClusterDraw web server is available at the following URL: http://flydev.berkeley.edu/cgi-bin/cld/submit.cgi

Contact:  dxp@berkeley.edu

Supplementary information: Supplementary data are available at Bioinformatics online.
Position dependencies in transcription factor binding sites
Authors: Tomovic Andrija , Oakeley Edward J.
Published: February 2007

Motivation: Most of the available tools for transcription factor binding site prediction are based on methods which assume no sequence dependence between the binding site base positions. Our primary objective was to investigate the statistical basis for either a claim of dependence or independence, to determine whether such a claim is generally true, and to use the resulting data to develop improved scoring functions for binding-site prediction.

Results: Using three statistical tests, we analyzed the number of binding sites showing dependent positions. We analyzed transcription factor–DNA crystal structures for evidence of position dependence. Our final conclusions were that some factors show evidence of dependencies whereas others do not. We observed that the conformational energy (Z-score) of the transcription factor–DNA complexes was lower (better) for sequences that showed dependency than for those that did not (P < 0.02). We suggest that where evidence exists for dependencies, these should be modeled to improve binding-site predictions. However, when no significant dependency is found, this correction should be omitted. This may be done by converting any existing scoring function which assumes independence into a form which includes a dependency correction. We present an example of such an algorithm and its implementation as a web tool.

Availability:  http://promoterplot.fmi.ch/cgi-bin/dep.html

Contact:  edward.oakeley@fmi.ch

Supplementary information: Supplementary data (1, 2, 3, 4, 5, 6, 7 and 8) are available at Bioinformatics online.
Postoperative Cognitive Dysfunction in Patients with Preoperative Cognitive Impairment
Authors: Silverstein Jeffrey H. , Steinmetz Jacob , Reichenberg Abraham , Harvey Philip D. , Rasmussen Lars S.
Published: February 2007

Background

The authors explored the database of the first International Study of Postoperative Cognitive Dysfunction study to specify the domains of cognitive function that were most vulnerable and to determine the pattern of deterioration in patients with preoperative cognitive impairment.

Methods

One thousand two hundred eighteen patients were included in the first International Study of Postoperative Cognitive Dysfunction, where neuropsychological testing was performed at entry to the study, at 1 week, and at 3 months after surgery. The authors' analyses determined the extent to which seven neuropsychological measures changed after surgery with focus on the relation with preoperative cognitive impairment, defined as a preoperative score 1.5 SD below healthy controls in the memory test.

Results

Preoperative cognitive impairment was found in 74 patients at baseline. At 1 week, cognitive deterioration was seen in all tests, but in particular in the Letter Digit Coding and the time of the Stroop interference test, with 14% and 16% of the total sample (n = 1,016) exceeding 2 SD, respectively. At 3 months, deterioration was more uniform. Significantly fewer in the preoperative cognitive impairment group had deterioration in the memory test, both at 1 week and at 3 months, with no patient displaying a deterioration exceeding 2 SD.

Conclusions

Postoperative cognitive deterioration was seen in all tests, although most commonly in attention and cognitive speed at 1 week. Deterioration in memory was difficult to detect after surgery in patients with preoperative cognitive impairment.
High-dose Morphine Impairs Vascular Endothelial Function by Increased Production of Superoxide Anions
Authors: Lam Chen-Fuh , Liu Yen-Chin , Tseng Fan-Ling , Sung Yen-Hui , Huang Chien-Chi , Jiang Meei-Jyh , Tsai Yu-Chuan
Published: February 2007

Background

The effects of high-dose morphine on vascular endothelial function have not been previously shown. The authors hypothesized that the pro-oxidant effect of high-dose morphine impairs vascular endothelial function.

Methods

Mice were subjected to placebo or morphine (20 mg/kg intraperitoneal) injection for consecutive 14 days. Aortas were harvested for assessment of vasomotor function by isometric force recordings. Protein expression p47phox was determined by Western blotting. Generations of superoxide anions were detected under a confocal microscope.

Results

Compared with controls, contraction response to phenylephrine was significantly enhanced in the aorta of mice treated with high-dose morphine (maximal contractions were 150 +/- 26 vs. 261 +/- 32 mg, respectively; n = 5 or 6, P = 0.04). Endothelium-dependent relaxations to acetylcholine (10 to 10 m) were significantly reduced in morphine-treated animals but were normalized by superoxide scavenging. Fluorescent densities of dihydroethidium were increased in the aorta of morphine-treated mice. Aorta of mice treated with morphine expressed higher levels of p47phox (a major subunit of nicotinamide adenine dinucleotide phosphate oxidase). In cultured endothelial cells, morphine enhanced production of reactive oxygen species.

Conclusions

Collectively, the authors' results showed that high-dose morphine impairs vascular endothelial function via attenuation of biologic activity of endothelium-derived nitric oxide. Chemical antagonism between superoxide anions generated by nicotinamide adenine dinucleotide phosphate oxidases may be the molecular mechanism responsible for the inactivation of endogenous nitric oxide after treatment with high-dose morphine.
Imaging Human Cerebral Pain Modulation by Dose-dependent Opioid Analgesia
Authors: Wagner Klaus J. , Sprenger Till , Kochs Eberhard F. , Tölle Thomas R. , Valet Michael , Willoch Frode
Published: February 2007

Background

Previous imaging studies have demonstrated a number of cortical and subcortical brain structures to be activated during noxious stimulation and infusion of narcotic analgesics. This study used O-water and positron emission tomography to investigate dose-dependent effects of the short-acting mu-selective opioid agonist remifentanil on regional cerebral blood flow during experimentally induced painful heat stimulation in healthy male volunteers.

Methods

Positron emission tomography measurements were performed with injection of 7 mCi O-water during nonpainful heat and painful heat stimulation of the volar forearm. Three experimental conditions were used during both sensory stimuli: saline, 0.05 microg x kg x min remifentanil, and 0.15 microg x kg x min remifentanil. Cardiovascular and respiratory parameters were monitored noninvasively. Across the three conditions, dose-dependent effects of remifentanil on regional cerebral blood flow were analyzed on a pixel-wise basis using a statistical parametric mapping approach.

Results

During saline infusion, regional cerebral blood flow increased in response to noxious thermal stimulation in a number of brain regions as previously reported. There was a reduction in pain-related activations with increasing doses of remifentanil in the thalamus, insula, and anterior and posterior cingulate cortex. Increasing activation occurred in the cingulofrontal cortex (including the perigenual anterior cingulate cortex) and the periaqueductal gray.

Conclusions

Remifentanil induced regional cerebral blood flow increases in the cingulofrontal cortex and periaqueductal gray during pain stimulation, indicating that mu-opioidergic activation modulates activity in pain inhibitory circuitries. This provides direct evidence that opioidergic analgesia is mediated by activation of established descending antinociceptive pathways.
Randomized, Controlled Trial of Early Intravenous Nutrition for Prevention of Neonatal Jaundice in Term and Near‐term Neonates
Authors: Makay Balahan , Duman Nuray , Özer Esra , Kumral Abdullah , Yeşilirmak Didem , Özkan Hasan
Published: February 2007

Background:

This study was undertaken to investigate the effects of early parenteral nutrition on prevention of neonatal jaundice in term and near‐term neonates who could not be enterally fed.

Patients and Methods:

Seventy‐two infants were randomized into 2 groups: the early parenteral nutrition group (group 1) received 1.0 g/kg/d amino acids beginning within the first day and 1.0 g/kg/d lipid added the next day. The conventional nutrition group (group 2) started on a solution containing 10% glucose and electrolytes in the first 72 hours of life, followed by 0.5 g/kg/d amino acids and lipid. Amino acids and lipid were each increased by 0.5 g/kg/d to a maximum of 3.0 g/kg/d in both groups. Main outcome measures were energy intake; serum bilirubin levels at 24, 48, and 72 hours; need for phototherapy; and duration of phototherapy.

Results:

Higher energy intake was achieved after the first day in group 1. Daily serum bilirubin levels did not significantly differ between groups. Nine patients in each group required phototherapy. The initiation times of phototherapy were 92.9 hours ± 25.5 in group 1 and 83.1 hours ± 28.5 in group 2. Durations of phototherapy were 37.3 hours ± 11.1 in group 1 and 52.0 hours ± 20.7 in group 2. There were no significant differences in the requirement, initiation time, and duration of phototherapy.

Conclusions:

Early parenteral nutrition has no proven benefit in terms of therapy requirement or severity and duration of neonatal jaundice compared with conventional parenteral nutrition in term and near‐term infants who could not be enterally fed.
Topical Application of Mitomycin‐C in Oesophageal Strictures
Authors: Rosseneu S , Afzal N , Yerushalmi B , Ibarguen‐Secchia E , Lewindon P , Cameron D , Mahler T , Schwagten K , Köhler H , Lindley KJ , Thomson M
Published: February 2007

Background:

Benign oesophageal strictures may occur as a complication of caustic ingestion or severe gastro‐oesophageal reflux or as a sequela of oesophageal surgery and other fibrosing conditions. The traditional initial treatment of oesophageal strictures is intraluminal dilation; however, even if frequent, this occasionally may not provide adequate oesophageal lumen capacity or give significant symptom‐free intervals, and restricturing after dilation is difficult and challenging. Topical postdilation application of an antifibrotic agent, mitomycin‐C, in the treatment of an oesophageal stricture has been described.

Patients and Methods:

Eight centres participated, with a total of 16 patients (4 girls), median age 48 (range 0–276) months. The causes of stricture were as follows: caustic (10), post–trachea‐oesophageal fistula repair (2), peptic (2), Crohn disease (1), and dystrophic epidermolysis bullosa (1). The median (range) length and diameter of the strictures were as follows: 22 mm (8–50 mm) and 1.5 mm (1–6 mm). Of the 16 patients, 15 had undergone repeated dilations varying from 3 to more than 1000 (daily self‐bouginage) before mitomycin‐C, and the median interval between dilations was 4 weeks. Mitomycin‐C 0.1 mg/mL was applied after dilation for a median time of 3.5 minutes and a median of 3 (1–12) times.

Results:

Major success, both endoscopic and clinical improvement or cure, occurred in 10 of 16 patients. In 3 of 16 patients the interval period between dilations increased dramatically. Failure of therapy was considered in 3 of 16. All of the patients remained symptom free for a follow‐up time of as long as 5 years.

Conclusions:

Postdilation application of topical mitomycin‐C resulted in major success in 62.5% of patients and partial success in 19%, and it may be a useful strategy in oesophageal strictures of differing causes that are refractory to repeated perendoscopic dilation.
Cyclooxygenase‐2 Expression in Polyps From a Patient With Juvenile Polyposis Syndrome With Mutant BMPR1A
Authors: Kurland Jayde E , Beck Stayce E , Solomon Carol J , Brann Oscar S , Carethers John M , Huang Sherry C
Published: February 2007

Objectives:

Cyclooxygenase‐2 (COX‐2) expression is increased in colorectal cancers and has been reported to be upregulated in Peutz‐Jeghers polyps. To determine whether germline and somatic loss of BMPR1A in polyps from a patient with juvenile polyposis syndrome have altered COX‐2 expression, we characterized a patient with juvenile polyposis syndrome for BMPR1A germline mutations and examined the polyps for BMPR1A expression and COX‐2 expression.

Patients and Methods:

DNA analysis for BMPR1A was performed on a patient with juvenile polyposis syndrome. Multiple polypectomies were performed, and several polyps showed adenomatous change. Genomic DNA was extracted from polyp material for loss of heterozygosity (LOH) analyses with microsatellite markers. Immunohistochemistry was performed on sections using antibodies for BMPR1A and COX‐2.

Results:

The kindred possessed a germline BMPR1A missense mutation. In polyp domains containing cystic and adenomatous epithelium, no LOH was observed using markers near the BMPR1A locus. Immunostaining indicated decreased expression of phospho‐SMAD1 (pSMAD1), functionally downstream of the mutant BMPR1A receptor in the cystic epithelium, with further reduction in adenomatous portions within the polyp. COX‐2 protein, normally not expressed in the colon, was present and increased in polyp epithelium.

Conclusions:

Decreased expression of pSMAD1 in the cystic epithelium with further reduction in the adenomatous area, and increase in COX‐2 expression within polyps from the BMPR1A heterozygote, suggest a potential mechanism for adenomatous pathogenesis in these hamartomatous polyps. This may imply that COX‐2 inhibitors could be a means for chemoprevention in this syndrome.
Epidermal Growth Factor Stimulates Chloride Transport in Primary Cultures of Weanling and Adult Rabbit Colonocytes
Authors: Carlos Maria A , Nwagwu Chimnoya , Ao Mei , Venkatasubramanian Jayashree , Boonkaewwan Chaiwat , Prasad Roli , Chowdhury Shamim AK , Vidyasagar Dharmapuri , Rao Mrinalini C
Published: February 2007

Objectives:

We have shown that Ca2+‐dependent regulation of Cl− secretion in the mammalian colon exhibits age dependence. Because epidermal growth factor (EGF) has a well‐established role in growth and can increase intracellular calcium [Ca2+]i, it is conceivable that its developmental influence may extend to the regulation of intestinal ion transport. In this study, we examined the role of EGF in the regulation of Cl− transport in the developing rabbit distal colon.

Materials and Methods:

Because serum contains growth factors, which could have confounded our studies, we first established an optimal milieu for testing EGF in primary cultures of adult rabbit distal colonocytes by culturing them for 24 h in media containing 0%, 1%, 5%, and 20% serum. Chloride transport (millimoles per second) and [Ca2+]i were measured with use of the fluorescent indicator N‐(ethoxycarbonylmethyl)‐6‐methoxyquinolinium bromide (MQAE) and Fura‐2AM, respectively.

Results:

Serum depletion had no effect on cell number, DNA content, or basal Cl− transport, but it significantly affected cell viability. In media with 0%, 1%, or 20% serum, bethanechol, 8BrcAMP, taurodeoxycholate, and EGF stimulated Cl− transport to a similar extent. EGF maximally stimulated Cl− transport at 16.3 nmol/L and 20 minutes. Bethanechol, but not EGF, increased [Ca2+]i. EGF did not alter bethanechol‐stimulated Cl− transport or [Ca2+]i. EGF acts via an EGF‐receptor and mitogen activated protein kinase (MAPK) signaling pathway, since stimulation of Cl− transport was abolished by genistein, AG1478, and PD98059. Weanling and adult colonocytes, cultured in 1% serum, showed similar basal and EGF‐stimulated Cl− transport.

Conclusions:

EGF stimulates rabbit colonic Cl− transport via a Ca2+‐independent, tyrosine kinase‐ and MAPK‐dependent pathway, and its effects are not age dependent.