bluuebunny/crossref_metadata_2025 huggingface dataset:
Nutrigenomic approaches for benefit-risk analysis of foods and food components: defining markers of health
Authors: Elliott Ruan , Pico Catalina , Dommels Yvonne , Wybranska Iwona , Hesketh John , Keijer Jaap
Published: August 2007

To be able to perform a comprehensive and rigorous benefit-risk analysis of individual food components, and of foods, a number of fundamental questions need to be addressed first. These include whether it is feasible to detect all relevant biological effects of foods and individual food components, how such effects can confidently be categorised into benefits and risks in relation to health and, for that matter, how health can be quantified. This article examines the last of these issues, focusing upon concepts for the development of new biomarkers of health. Clearly, there is scope for refinement of classical biomarkers so that they may be used to detect even earlier signs of disease, but this approach defines health solely as the absence of detectable disease or disease risk. We suggest that the health of a biological system may better be reflected by its ability to withstand and manage relevant physiological challenges so that homeostasis is maintained. We discuss the potential for expanding the range of current challenge tests for use in conjunction with functional genomic technologies to develop new types of biomarkers of health.
Lactobacillus caseiShirota administered during lactation increases the duration of autoimmunity in rats and enhances lung inflammation in mice
Authors: Ezendam Janine , van Loveren Henk
Published: August 2007

Probiotics are considered to have beneficial effects on the immune system. An association between the composition of microflora and allergies has been demonstrated and modulation of microflora of infants by probiotics might reduce the risk of allergies. To investigate immune effects of probiotics administered early after birth two animal models were used: a mouse model for respiratory allergy; a rat model for experimental autoimmune encephalomyelitis (EAE). Administration of the probioticLactobacillus caseiShirota (LcS) started during lactation and allergy or autoimmunity were induced at an adult age. Results were compared with similar studies in rats and mice that were exposed from an adult age. Early administration of LcS significantly increased lymphocytes in the lungs of female mice and eosinophils in the lungs of male mice. LcS had no effects on ovalbumin-specific serum IgE levels and on ovalbumin-specific cytokine production by spleen cells. In adult mice, LcS enhanced ovalbumin-specific cytokine production by the spleen, whereas other parameters were not affected. Early administration of LcS to rats significantly increased the duration of clinical symptoms of EAE. This was also demonstrated previously in adult rats exposed to LcS. Timing of administration of LcS induced divergent effects on respiratory allergy and only early administration of LcS exacerbated lung inflammation. In the EAE model, LcS stimulated autoimmunity independent of the timing of administration. Our data show that immune effects of probiotics do not necessarily induce beneficial effects. It is therefore important that, in the evaluation of probiotics, efficacy and safety should be demonstrated.
Association of fruit and vegetable intake with cardiovascular risk factors in urban south Indians
Authors: Radhika Ganesan , Sudha Vasudevan , Mohan Sathya Rangaswamy , Ganesan Anbazhagan , Mohan Viswanathan
Published: August 2007

The study examines the relationship between fruit and vegetable intake (g/d) and CVD risk factors in urban south Indians. The study population comprised of 983 individuals aged ≥ 20 years selected from the Chennai Urban Rural Epidemiological Study (CURES), a population-based cross-sectional study on a representative population of Chennai in southern India. Fruit and vegetable intake (g/d) was measured using a validated semi-quantitative FFQ. Linear regression analysis revealed that after adjusting for potential confounders such as age, sex, smoking, alcohol, BMI and total energy intake, the highest quartile of fruit and vegetable intake (g/d) showed a significant inverse association with systolic blood pressure (β = − 2·6 (95 % CI − 5·92, − 1·02) mmHg; P = 0·027), BMI (β = − 2·3 (95 % CI − 2·96, − 1·57) kg/m2; P < 0·0001), waist circumference (β = − 2·6 (95 % CI − 3·69, − 1·46) cm; P < 0·0001), total cholesterol (β = − 50 (95 % CI − 113·9, − 13·6) mg/l; P = 0·017) and LDL-cholesterol concentration (β = − 55 (95 % CI − 110·8, − 11·1) mg/l; P = 0·039) when compared with the lowest quartile. A higher intake of fruit and vegetables explained 48 % of the protective effect against CVD risk factors. Increased intake of fruits and vegetables could play a protective role against CVD in Asian Indians who have high rates of premature coronary artery disease.
Characterization of actin genes inBonamia ostreaeand their application to phylogeny of the Haplosporidia
Authors: LÓPEZ-FLORES I. , SUÁREZ-SANTIAGO V. N. , LONGET D. , SAULNIER D. , CHOLLET B. , ARZUL I.
Published: August 2007

Bonamia ostreaeis a protozoan parasite that infects the European flat oysterOstrea edulis, causing systemic infections and resulting in massive mortalities in populations of this valuable bivalve species. In this work, we have characterizedB. ostreaeactin genes and used their sequences for a phylogenetic analysis. Design of different primer sets was necessary to amplify the central coding region of actin genes ofB. ostreae. Characterization of the sequences and their amplification in different samples demonstrated the presence of 2 intragenomic actin genes inB. ostreae, without any intron. The phylogenetic analysis placedB. ostreaein a clade withMinchinia tapetis,Minchinia teredinisandHaplosporidium costaleas its closest relatives, and demonstrated that the paralogous actin genes found inBonamiaresulted from a duplication of the original actin gene after theBonamiaorigin.
Toxoplasmosis in prey species and consequences for prevalence in feral cats: not all prey species are equal
Authors: AFONSO E. , THULLIEZ P. , PONTIER D. , GILOT-FROMONT E.
Published: August 2007

Toxoplasma gondiiis largely transmitted to definitive felid hosts through predation. Not all prey species represent identical risks of infection for cats because of differences in prey susceptibility, exposure and/or lifespan. Previously published studies have shown that prevalence in rodent and lagomorph species is positively correlated with body mass. We tested the hypothesis that different prey species have different infection risks by comparing infection dynamics of feral cats at 4 sites in the sub-Antarctic Kerguelen archipelago which differed in prey availability. Cats were trapped from 1994 to 2004 and anti-T. gondiiIgG antibodies were detected using the modified agglutination test (⩾1:40). Overall seroprevalence was 51·09%. Antibody prevalence differed between sites, depending on diet and also on sex, after taking into account the effect of age. Males were more often infected than females and the difference between the sexes tended to be more pronounced in the site where more prey species were available. A difference in predation efficiency between male and female cats may explain this result. Overall, our results suggest that the composition of prey items in cat diet influences the risk ofT. gondiiinfection. Prey compositon should therefore be considered important in any understanding of infection dynamics ofT. gondii.
‘It's not over when it's over’: persistent neurobiological abnormalities in recovered depressed patients
Authors: Bhagwagar Z. , Cowen P.J.
Published: August 2007

The tendency of major depression to recur is a leading problem in clinical management and is responsible for much of the illness burden. Until recently, biological studies of depression have focused on the mechanisms involved in acute illness but there are now many data to suggest that neurobiological abnormalities persist when depressed patients are clinically recovered and withdrawn from medication. These abnormalities encompass a number of neurochemical and neuropsychological mechanisms that could be relevant to recurrence, including changes in the availability of serotonin (5-hydroxytryptamine, 5-HT) receptor subtypes, decreases in cortical γ-aminobutyric acid (GABA), increases in cortisol secretion and negative biases in the processing of emotional information. Studies of groups at high risk of depression before illness onset will help to clarify which biological abnormalities precede the development of depression and which are the product of recurrent illness. Ultimately this work should lead to a better understanding of the neurobiology of vulnerability to depression and more innovative approaches to primary and secondary prevention.
A multi-data source surveillance system to detect a bioterrorism attack during the G8 Summit in Scotland
Authors: MEYER N. , McMENAMIN J. , ROBERTSON C. , DONAGHY M. , ALLARDICE G. , COOPER D.
Published: August 2007

In 18 weeks, Health Protection Scotland (HPS) deployed a syndromic surveillance system to early-detect natural or intentional disease outbreaks during the G8 Summit 2005 at Gleneagles, Scotland. The system integrated clinical and non-clinical datasets. Clinical datasets included Accident & Emergency (A&E) syndromes, and General Practice (GPs) codes grouped into syndromes. Non-clinical data included telephone calls to a nurse helpline, laboratory test orders, and hotel staff absenteeism. A cumulative sum-based detection algorithm and a log-linear regression model identified signals in the data. The system had a fax-based track for real-time identification of unusual presentations. Ninety-five signals were triggered by the detection algorithms and four forms were faxed to HPS. Thirteen signals were investigated. The system successfully complemented a traditional surveillance system in identifying a small cluster of gastroenteritis among the police force and triggered interventions to prevent further cases.
Understanding the impact of Hib conjugate vaccine on transmission, immunity and disease in the United Kingdom
Authors: McVERNON J. , RAMSAY M. E. , McLEAN A. R.
Published: August 2007

A rise in invasiveHaemophilus influenzaetype b (Hib) infections occurred 8 years after vaccine introduction in the United Kingdom. Aspects of Hib vaccine delivery unique to the United Kingdom have been implicated. The authors developed a fully age-structured deterministic susceptible–infected–resistant–susceptible mathematical model, expressed as a set of partial differential equations, to better understand the causes of declining vaccine effectiveness. We also investigated the consequences of the vaccine's impact on reducing Hib transmission for maintenance of immunity. Our findings emphasized the importance of maintaining high post-immunization antibody titres among age groups at greatest risk of invasive infections. In keeping with UK population-based estimates, low direct efficacy of immunological memory against disease was found, cautioning against over-reliance on evidence of priming alone as a correlate of population protection. The contribution of herd immunity to disease control was reinforced. Possible intervention strategies will be explored in subsequent work.
Risk factors for ciprofloxacin resistance in reported Campylobacter infections in southern Alberta
Authors: JOHNSON J. Y. M. , McMULLEN L. M. , HASSELBACK P. , LOUIE M. , JHANGRI G. , SAUNDERS L. D.
Published: August 2007

We conducted a case-control study examining risk factors for ciprofloxacin resistance in Campylobacter infections that were reported in 2004 and 2005 in two health regions in southern Alberta. The study questionnaire included questions about recent travel and antibiotic use, food consumption frequency, use of household and personal hygiene products with antibacterial agents, contact with animals, and potential misuse of antibiotics. Of the 210 patients who participated, 31·0% had ciprofloxacin-resistant Campylobacter infections. Foreign travel was the strongest predictor of resistance. Surprisingly, possession of antibiotics for future use was identified as a risk factor for resistance. We also examined the potential for participation bias and resistance misclassification to affect the resulting multivariable models. Participation bias appears to have had a substantial effect on the model results, but the estimated misclassification effect due to the use of different ciprofloxacin susceptibility testing methods was only slight.
Prevalence ofStaphylococcus aureuscarriage among dogs and their owners
Authors: BOOST M. V. , O'DONOGHUE M. M. , JAMES A.
Published: August 2007

Case reports have indicated transmission ofStaphylococcus aureusbetween humans and pets. We investigated associations between level of contact between dog and owner, andS. aureuscolonization. In a cross-sectional study, nasal carriage and antibiotic susceptibility ofS. aureuswas determined for 830 dogs and 736 owners. Relatedness of isolates was investigated using antibiograms and pulsed-field gel electrophoresis (PFGE). Associations between carriage and demographics or amount of contact between owners and dogs were documented.S. aureuswas isolated in 24% of humans and 8·8% of dogs. Antibiotic resistance was significantly more common in canine isolates. Of 17 owner/dog colonized pairs, six were indistinguishable by PFGE. Colonization of dogs was not associated with close human contact, but was strongly associated with health-care occupations (OR 3·29, 95% CI 1·49–7·26,P=0·002). In outbreak situations health-care workers' pets should be considered as a source ofS. aureus. High rates of resistance indicate increased monitoring of antibiotic use in veterinary practice is needed.
Food and trust in Australia: building a picture
Authors: Coveney John
Published: August 2007

Objective

To explore consumer trust in food, especially people’s experiences that support or diminish trust in the food supply; consumer practices to strengthen trust in food; and views on how trust in the food supply could be increased.

Setting

Adelaide, South Australia.

Design

In-depth qualitative research interviews and focus groups.

Subjects

Women and men who are primary food providers in families (n= 24).

Results

Media coverage of food scares and scandals and personal experience of food-borne illness challenged respondents’ trust in the food system. Poor retail food handling practices and questionable marketing ploys by food manufacturers also decreased trust. Buying ‘Made-in-Australia’ produce and following food safety procedures at home were important practices to strengthen food trust. Knowledge of procedures for local food inspection and for national food regulation to keep food safe was scanty. Having a strong regulatory environment governing food safety and quality was considered by respondents to be of prime importance for trust building.

Discussion

The dimensions of trust found in this study are consistent with key theoretical aspects of trust. The need for trust in highly complex environments, in this case the food supply, was evident. Trust was found to be integral to food choice, and negative media reports, the sources of which themselves enjoy various levels of dependability, were found to easily damage trust relationships. The lack of visibility of authoritative monitoring and surveillance, misleading food advertising, and poor retail food handling practices were identified as areas that decreased consumer trust. Respondents also questioned the probity of food labelling, especially health claims and other mechanisms designed to guide food choice. The research highlights the role trust plays in food choice. It also emphasises the importance of a visible authoritative presence in the food system to strengthen trust and provide reassurance to consumers.
Principal component analysis and modeling of the subsidence of the shoreline of Lake Taupo, New Zealand, 1983–1999: Evidence for dewatering of a magmatic intrusion?
Authors: Smith Euan G. C. , Williams Timothy D. , Darby Desmond J.
Published: August 2007

Principal component analysis was applied to a set of relative water level measurements made at 22 sites around Lake Taupo, New Zealand, in 37 surveys during 1986–1996. Only a single mode was significantly above noise levels. This mode showed a subsidence of the lake shore that decayed exponentially with time, with a time constant of about 12 years. The mode was well modeled by a Mogi point dilatation at a depth of 8 ± 1 km located beneath the point with the greatest rate of subsidence, which was about 8.5 ± 1 mm yr−1, in the center of the northern lake shore. The model implies that the source contracted by 0.02 ± 0.002 km3 during 1986–1996. Three model parameters, the time constant, the depth, and the volume contraction, place constraints on the physical process or processes that caused the contraction and resulting lake shore subsidence. We infer that magma was intruded into the crust beneath the north shore of the lake at some time prior to the start of the lake shore observations in 1979 and that the contraction was due to water leaving the melt because of decompression. For this to work, the water must diffuse quickly away from the source, and we accordingly infer that the permeability of the overlying crust must be 10−15 m2 or greater. To match the observed source contraction, and assuming a 1% by weight fluid loss, the magma would have to have contained about 2.5 km3 or more of melt.
Signal and noise in Gravity Recovery and Climate Experiment (GRACE) observed surface mass variations
Authors: Schrama Ernst J. O. , Wouters Bert , Lavallée David A.
Published: August 2007

The Gravity Recovery and Climate Experiment (GRACE) product used for this study consists of 43 monthly potential coefficient sets released by the GRACE science team which are used to generate surface mass thickness grids expressed as equivalent water heights (EQWHs). We optimized both the smoothing radius and the level of approximation by empirical orthogonal functions (EOFs) and found that 6.25° and three modes are able to describe more than 73.5% of the variance. The EQWHs obtained by the EOF method describe all known variations in the continental hydrology, present‐day ice sheet melting, and global isostatic adjustment. To assess the quality of the estimated grids, we constructed degree error spectra of EQWHs. We conclude that a significant part of the errors in GRACE can be explained by a scaling factor of 0.85 relative to degree error estimates provided by the GGM02C gravity model but that the present‐day errors in the GRACE data are a factor 2 to 5 larger than forecasted by tide model differences and atmospheric pressure differences. Comparison to a network of 59 International GNSS Service (IGS) stations confined the filter parameter settings to three EOF modes and 5° or 6.25° smoothing radius. Residuals that remain after the EOF method do exhibit S2 aliasing errors and a semiannual continental hydrology signal contained in the Global Land Data Assimilation Systems (GLDAS) model. Further analysis of the residual EOF signal revealed alternating track correlation patterns that are partially explained by the GRACE covariance matrix and the handling of nuisance parameters in the GRACE data processing.
Three‐dimensional fractal modeling of intracloud lightning discharge in a New Mexico thunderstorm and comparison with lightning mapping observations
Authors: Riousset Jeremy A. , Pasko Victor P. , Krehbiel Paul R. , Thomas Ronald J. , Rison William
Published: August 2007

The direct comparison of lightning mapping observations by the New Mexico Tech Lightning Mapping Array (LMA) with realistic models of thundercloud electrical structures and lightning discharges represents a useful tool for studies of electrification mechanisms in thunderstorms, initiation and propagation mechanisms of different types of lightning discharges as well as for understanding of electrical and energetic effects of tropospheric thunderstorms on the upper regions of the Earth's atmosphere. This paper presents the formulation of a new three‐dimensional probabilistic model for investigating the structure and development of bidirectional positive and negative lightning leaders. The results closely resemble structures observed by the LMA during intracloud discharges. The model represents a synthesis of the original dielectric breakdown model based on fractal approach proposed by Niemeyer et al. (1984) and the equipotential lightning channel hypothesis advanced by Kasemir (1960) and places special emphasis on obtaining self‐consistent solutions preserving complete charge neutrality of the discharge trees at any stage of the simulation. A representative simulation run is compared to a typical intracloud discharge measured by LMA in a New Mexico thunderstorm on 31 July 1999. Following the conclusions from Coleman et al. (2003), the comparison of the model and observed discharges reveals that an adequate choice of the electrical structure of the model thundercloud permits the development of a model intracloud discharge reproducing principal features of the observed event including the initial vertical extension of the discharge between the main negative and upper positive charge regions of the thundercloud, and the subsequent horizontal propagations in these regions. Also consistent with observations (e.g., Coleman et al., 2003), negative and positive leaders mainly develop in the upper positive and main negative charge regions, respectively. For the particular model case presented in this paper, the total charge transfer, the vertical dipole moment and the average linear charge density associated with the development of bidirectional structure of leader channels are estimated to be 37.5 C, 122 C·km, and 0.5 mC/m, respectively, in good agreement with related data reported in the refereed literature. The model results also demonstrate that the bulk charge carried by the integral action of positive and negative leaders leads to a significant (up to 80%) reduction of the electric field values inside the thundercloud, significantly below the lightning initiation threshold.
Influences of urbanization on surface characteristics as derived from the Moderate‐Resolution Imaging Spectroradiometer: A case study for the Beijing metropolitan area
Authors: Wang Kaicun , Wang Jiankai , Wang Pucai , Sparrow Michael , Yang Juan , Chen Hongbin
Published: August 2007

Moderate‐Resolution Imaging Spectroradiometer (MODIS) global land surface temperature/emissivity (LST), vegetation indices, BRDF/Albedo and land cover products collected for the period of March 2000 to March 2006 are combined with the surface heat fluxes retrieved from MODIS as well as meteorological data to investigate the influence of urbanization associated with the surface characteristics of the city of Beijing. The results show that the use of different rural areas in the urban heat island (UHI) calculation influences the value of UHI and its seasonal variation. Daytime UHI shows a distinct seasonal variation, the maximum during summer being larger than 10°C, while conspicuous negative UHI occurs in winter and spring. Seasonal variation of nighttime UHI is much less. The contrast in thermal inertia between rural and urban areas, anthropogenic heat from the urban area and less latent heat flux over urban areas are the main factors influencing daytime UHI, whereas anthropogenic heat controls the nighttime UHI. Surface broadband emissivity derived from MODIS LST/emissivity for the urban area is nearly equal to the rural areas. Surface albedo over the urban area is 0.03–0.08 less than that of rural areas, but aerosols substantially reduce surface incoming solar radiation over the urban area, which results in the surface absorbed solar radiation being nearly equal for urban and rural areas during autumn. Diurnal variation of UHI demonstrates a distinctively seasonal variation. The accuracy of MODIS LST is investigated and it was found that the influence of satellite view angle on the calculated UHI is small enough to be ignored.
Layered mantling deposits in northeast Arabia Terra, Mars: Noachian‐Hesperian sedimentation, erosion, and terrain inversion
Authors: Fassett Caleb I. , Head James W.
Published: August 2007

Thick, layered mantling deposits of different ages occur in several nonpolar regions of Mars and are thought to represent volcanic ash and/or climate‐related ice‐dust deposition. One such deposit is a layered mantling unit that unconformably blanketed highlands terrain in northeast Arabia Terra during the Late Noachian and/or earliest Hesperian. Shortly thereafter, by the mid‐Hesperian, this deposit was substantially eroded; on the basis of its superposed crater population, it appears to have subsequently retained its approximate morphology and distribution in the ∼3.5 Gyr since. When the erosion occurred, in the Early Hesperian, the mantling unit was more resistant in some areas than its surroundings, resulting in inversion of relief: craters were transformed into highstanding buttes, and valleys were transformed into isolated ridges. On the basis of the scale of the observed inversion of relief, the magnitude of erosion in northeast Arabia Terra was substantial, up to hundreds of meters. We have used newly available data to assess the nature of the mantling material and probable mechanisms for its deposition and removal. We find that (1) the mantle unit is layered at scales of meters to tens of meters; (2) the deposit has a median thickness of ∼60 m, and the thickness of the deposit was locally controlled by the topography at the time of its deposition; (3) the mantling unit thins toward the south; and (4) characteristics of the mantling unit, such as its induration, as well as observed pits and fractures, suggest that volatiles may have been incorporated into the mantling unit either during or following its emplacement. Taken together, our observations lead us to favor models for the deposition of the mantling unit involving airfall of dust or ash. Either climate‐driven dust deposition or plinian volcanic eruptions from the nearby Syrtis Major volcanic province are plausible candidate models for the emplacement of the unit in time and space.
Linkage of sediment supply and transport processes in Miyagawa Dam catchment, Japan
Authors: Imaizumi Fumitoshi , Sidle Roy C.
Published: August 2007

Linkages between sediment supply by episodic geomorphic processes (obtained from aerial photographs and field surveys) and sediment transport (estimated from changes in sediment deposition behind a large dam) were investigated in the Miyagawa Dam catchment, central Japan. A total of 6667 landslides were confirmed in the period from 1965 to 2000 on the basis of seven temporal pairs of aerial photographs. Both the occurrence of landslides and discharge into the dam lake affect sediment yield, indicating that fluvial systems in Miyagawa Dam catchment are supply limited with respect to sediment. Sediment yields are affected by not only the initial failed volume of landslides but also the mobility of landslides and debris flows. In Miyagawa Dam catchment, percentages of landslides reaching channels varied from 56% in 1997–2000 to 75% in 1976–1981 and were correlated with maximum hourly rainfall. In addition, the mobility of debris flows was higher during periods with high maximum instantaneous discharge compared to lower discharge, suggesting that the water content both in initially failed materials and transported sediment controlled their mobility. Topography also affected the mobility of landslides/debris flows. For catchments >0.1 km2, the percentage of channel network length impacted by debris flows decreased with increasing catchment area due to reduced channel gradient. Thus both the magnitude of rainfall‐runoff events and the catchment topography affect how landslide sediment contributes to sediment yield at the large catchment scale.
A simple mechanism for irreversible tidewater glacier retreat
Authors: Pfeffer W. T.
Published: August 2007

Tidewater glacier retreat is abrupt and typically irreversible. The mechanics of abrupt onset are evaluated by considering the behavior of a sliding law that depends inversely upon effective pressure (pice − pwater); for such a law, flux can increase with decreasing thickness if the loss of bed traction exceeds the loss of driving stress. Characteristic values of increased flux and glacier thinning are shown to propagate upstream if ice flux increases with decreasing thickness below an ice thickness threshold determined by the chosen sliding law. Upstream propagation leads to instability, described in earlier literature, in which increased flow leads to thinning, loss of bed traction, and continued acceleration. In simplest terms, the instability arises when alterations in glacier geometry act to reduce resistive stresses more than driving stresses. The effects of diffusion are also analyzed, and it is shown that for the form of sliding law considered here, diffusion will not necessarily eliminate upstream‐propagating instabilities. Application of this theory shows that a transition from stable to unstable conditions occurred at Columbia Glacier, Alaska, near the time of onset of its retreat in the early 1980s. The theory also successfully predicts stable or rapidly retreating states for 12 other Alaska tidewater glaciers, and its applicability to Greenland outlet glaciers is discussed.
Uncertainty assessment in watershed‐scale water quality modeling and management: 1. Framework and application of generalized likelihood uncertainty estimation (GLUE) approach
Authors: Zheng Yi , Keller Arturo A.
Published: August 2007

Watershed‐scale water quality models involve substantial uncertainty in model output because of sparse water quality observations and other sources of uncertainty. Assessing the uncertainty is very important for those who use the models to support management decision making. Systematic uncertainty analysis for these models has rarely been done and remains a major challenge. This study aimed (1) to develop a framework to characterize all important sources of uncertainty and their interactions in management‐oriented watershed modeling, (2) to apply the generalized likelihood uncertainty estimation (GLUE) approach for quantifying simulation uncertainty for complex watershed models, and (3) to investigate the influence of subjective choices (especially the likelihood measure) in a GLUE analysis, as well as the availability of observational data, on the outcome of the uncertainty analysis. A two‐stage framework was first established as the basis for uncertainty assessment and probabilistic decision‐making. A watershed model (watershed analysis risk management framework (WARMF)) was implemented using data from the Santa Clara River Watershed in southern California. A typical catchment was constructed on which a series of experiments was conducted. The results show that GLUE can be implemented with affordable computational cost, yielding insights into the model behavior. However, in complex watershed water quality modeling, the uncertainty results highly depend on the subjective choices made by the modeler as well as the availability of observational data. The importance of considering management concerns in the uncertainty estimation was also demonstrated. Overall, this study establishes guidance for uncertainty assessment in management‐oriented watershed modeling. The study results have suggested future efforts we could make in a GLUE‐based uncertainty analysis, which has led to the development of a new method, as will be introduced in a companion paper. Eventually, the study should assist in the development of a new generation of watershed water quality models.
Uncertainty assessment in watershed‐scale water quality modeling and management: 2. Management objectives constrained analysis of uncertainty (MOCAU)
Authors: Zheng Yi , Keller Arturo A.
Published: August 2007

Watershed‐scale water quality models are increasingly used to support management decision making. However, significant uncertainty in model output remains an unaddressed issue. In our first study, a framework for assessing the uncertainty in watershed modeling and management was developed, and the application of the generalized likelihood uncertainty estimation (GLUE) approach was examined. The influence of subjective choices (especially the likelihood measure) in a GLUE analysis, as well as of availability of observational data, was investigated. On the basis of GLUE, we developed a new Bayesian approach of uncertainty analysis, specifically for management‐oriented watershed water quality modeling, as introduced in this paper. The approach, named management objectives constrained analysis of uncertainty (MOCAU), inherits GLUE's equifinality ideology while explicitly considering management objectives and observational uncertainty. It has many unique features that have not been covered (or have not been explored in great detail) by previous GLUE studies. A series of experiments was conducted to investigate the performance of MOCAU. The results show that MOCAU can be applied efficiently, generating accurate uncertainty estimates for management applications. Subjective assumptions in the uncertainty analysis are explicit and realistic, on the basis of management objectives such as nonattainment frequency of water quality objectives. MOCAU also yields insights into watershed model structure improvement and strategic data collection to reduce uncertainty. Besides water quality modeling, MOCAU can also be applied to other complicated modeling problems where errors are significant, observational data is limited, and management objectives are involved.
Reconciling late Neogene Pacific absolute and relative plate motion changes
Authors: Wessel Paul , Kroenke Loren W.
Published: August 2007

New models of Pacific absolute plate motion relative to hot spots and models of relative plate motion involving the Pacific plate all agree there was a significant change in the late Neogene (Chron 3A, ∼5.89 Ma), reflecting a more northerly absolute motion than previously determined. As Pacific absolute plate motion became slightly more northerly, left‐stepping transform segments came under compression. Some left‐stepping segments became microplates with clockwise rotation; others show clear evidence of compressional deformation. Conversely, right‐stepping transforms came under tension, and many developed intratransform spreading centers or show similar evidence for transform magmatism. Several large left‐stepping transform offsets represent portions of the Nazca plate protruding into the Pacific and as such act as obstacles to the more northerly Pacific absolute plate motion. We suggest these obstructions act to enhance the generally tensile equatorial Pacific stress regime caused by distant slab pull. As a consequence, the greater French Polynesia region has experienced diffuse volcanism that increased considerably following the Chron 3A plate motion change. We propose that since the Hawaii‐Emperor Bend time, the distant Pacific slab pull and the friction between the large, buoyant Ontong Java plateau and the northern margin of the Australia plate have produced episodes of increased tensile stresses in the equatorial Pacific. We believe these stress excursions are responsible for much of the intraplate volcanism observed in a wide triangular region from Samoa to the East Pacific and Pacific‐Antarctic Rises.
TRMM‐TMI satellite observed soil moisture and vegetation density (1998–2005) show strong connection with El Niño in eastern Australia
Authors: Liu Yi , de Jeu Richard A. M. , van Dijk Albert I. J. M. , Owe Manfred
Published: August 2007

Spatiotemporal patterns in soil moisture and vegetation water content across mainland Australia were investigated from 1998 through 2005, using TRMM/TMI passive microwave observations. The Empirical Orthogonal Function technique was used to extract dominant spatial and temporal patterns in retrieved estimates of moisture content for the top 1‐cm of soil (θ) and vegetation moisture content (via optical depth τ). The dominant temporal θ and τ patterns were strongly correlated to the El Niño Southern Oscillation Index (SOI) in spring (r2 = 0.90), and to a progressively lesser extent autumn, summer and winter. The Indian Ocean Dipole (IOD) index also explained part of the variation in spring θ and τ. Correlation analysis suggested that the regions most affected by El Niño are mainly located in eastern Australia. The results suggest that the drought conditions experienced in eastern Australia since 2000 and clearly expressed in these satellite observations have a strong connection with El Niño.
Retrieving snow mass from GRACE terrestrial water storage change with a land surface model
Authors: Niu Guo‐Yue , Seo Ki‐Weon , Yang Zong‐Liang , Wilson Clark , Su Hua , Chen Jianli , Rodell Matthew
Published: August 2007

A reliable snow water equivalent (SWE) product is critical for climate and hydrology studies in Arctic regions. Passive microwave sensors aboard satellites provide a capability of observing global SWE and have produced many SWE datasets. However, these datasets have significant errors in boreal forest regions and where snowpack is deep or wet. The Gravity Recovery and Climate Experiment (GRACE) satellites are measuring changes in terrestrial water storage (TWS), of which snow mass is the primary component in winter Arctic river basins. This paper shows SWE can be derived from GRACE TWS change in regions where the ground is not covered by snow in a summer month if accurate changes in below‐ground water storage (including soil water and groundwater) can be provided by a land surface model. Based on gravity change, the GRACE‐derived SWE estimates are not affected by the boreal forest canopy and are more accurate in deep snow regions than microwave retrievals. The paper also discusses the uncertainties in the SWE retrievals.
Improved ground‐based liquid water path retrievals using a combined infrared and microwave approach
Authors: Turner D. D.
Published: August 2007

Radiative transfer modeling through cloudy atmospheres requires accurate measurement of the cloud properties. In liquid water clouds, accurate measurements of the liquid water path (LWP) are required, especially when the LWP is less than 100 g/m2. A new ground‐based retrieval algorithm was developed that retrieves LWP using infrared (8–13 μm and 3–4 μm) and microwave (23.8 and 31.4 GHz) radiance observations, as microwave radiance is sensitive to a large range of LWP (less than 5 to over 1000 g/m2) and infrared radiance is extremely sensitive to LWP less than approximately 60 g/m2. The random error in the retrieved LWP is estimated to be less than 4% when the LWP is less than 50 g/m2 but, for larger LWPs, it increases to at least 12 g/m2. The algorithm is also able to retrieve effective radius (re) when the LWP is less than approximately 60 g/m2. This new retrieval algorithm was applied to data collected by the Atmospheric Radiation Measurement (ARM) program's Mobile Facility at Pt. Reyes, California, from July to August 2005. Daytime retrieved re values agree well to airborne in situ observations, with a mean bias of 0.11 μm. A radiative transfer model utilizing the retrieved cloud properties was used to compute the surface and top of the atmosphere fluxes. The flux residuals (observed minus calculated) demonstrate a significant reduction in scatter (approximately a factor of 2 for LWP < 40 g/m2) relative to flux calculations where the cloud properties were determined by the microwave‐only retrieval algorithm MWRRET.
Contribution of High Frequencies to Speech Recognition in Quiet and Noise in Listeners With Varying Degrees of High-Frequency Sensorineural Hearing Loss
Authors: Amos Nathan E. , Humes Larry E.
Published: August 2007

Purpose

The contribution of audible high-frequency information to speech-understanding performance in listeners with varying degrees of high-frequency sensorineural hearing loss was examined.

Method

Thirty-six elderly hearing-impaired (EHI) and 24 young normal-hearing (YNH) listeners were tested in quiet (+20 dB speech-to-noise ratio [SNR]) and noise (+5 dB SNR) and under different bandpass conditions (narrow, 200–1600 Hz; midband, 200–3200 Hz; broadband, 200–6400 Hz), both without and with spectral shaping of the stimuli. Monosyllabic word-recognition performance was examined through use of both whole-word scoring and phoneme scoring. The 36 EHI listeners were divided into 3 groups of 12 listeners each, with the groups differing in the amount of high-frequency hearing loss. The 24 YNH participants were separated into 2 groups, each serving as a reference group for either the unshaped or spectrally shaped speech listening conditions.

Results

Results for spectrally shaped speech, in both quiet and noise, revealed that the 3 EHI groups performed equivalently in the different bandwidth conditions and demonstrated no change (increase or decrease) in word-recognition performance between the midband and broadband conditions. The YNH groups, however, demonstrated improved speech understanding attributable to the higher frequencies for the broadband condition in both the unshaped and shaped conditions.

Conclusions

Data from the EHI listeners revealed that performance for unshaped speech was correlated moderately and negatively with degree of high-frequency hearing loss. Alternatively, recognition performance for shaped speech was related to neither the performance for unshaped speech nor the amount of high-frequency hearing loss.
The Effects of Speech Presentation Level on Acceptance of Noise in Listeners With Normal and Impaired Hearing
Authors: Freyaldenhoven Melinda C. , Plyler Patrick N. , Thelin James W. , Hedrick Mark S.
Published: August 2007

Purpose

To compare the effects of speech presentation level on acceptance of noise in listeners with normal and impaired hearing.

Method

Participants were listeners with normal (
n
= 24) and impaired (
n
= 46) hearing who were matched for conventional acceptable noise level (ANL). ANL was then measured at 8 fixed speech presentation levels (40, 45, 50, 55, 60, 65, 70, and 75 dB HL) to determine if global ANL (i.e., ANL averaged across speech presentation levels) or ANL growth (i.e., the slope of the ANL function) varied between groups.

Results

The effects of speech presentation level on acceptance of noise were evaluated using global ANLs and ANL growth. Results showed global ANL and ANL growth were not significantly different for listeners with normal and impaired hearing, and neither ANL measure was related to pure-tone average for listeners with impaired hearing. Additionally, conventional ANLs were significantly correlated with both global ANLs and ANL growth for all listeners.

Conclusion

These results indicate that the effects of speech presentation level on acceptance of noise are not related to hearing sensitivity. These results further indicate that a listener’s conventional ANL was related to his or her global ANL and ANL growth.
Vocal Fold Epithelial Response to Luminal Osmotic Perturbation
Authors: Sivasankar Mahalakshmi , Fisher Kimberly V.
Published: August 2007

Purpose

Dry-air challenges increase the osmolarity of fluid lining the luminal surface of the proximal airway. The homeostasis of surface fluid is thought to be essential for voice production and laryngeal defense. Therefore, the authors hypothesized that viable vocal fold epithelium would generate a water flux to reduce an osmotic challenge (150 mOsm mannitol) on the lumen. Bidirectional transepithelial water fluxes were measured in vocal folds exposed to physiologically realistic luminal osmotic perturbations in vitro.

Method

Thirty-six native ovine vocal folds were exposed to either luminal hyperosmotic or isosmotic perturbations. Vocal fold viability and water fluxes toward the lumen and into the mucosa were measured at prechallenge baseline and for 30 min after challenge.

Results

Vocal fold electrophysiological viability was maintained for the duration of osmotic perturbation. Luminal osmotic exposure increased luminally directed transepithelial water fluxes in 60% of vocal folds. This increase was electrically silent, of short duration, and would not negate the osmotic gradient.

Conclusion

Ovine vocal fold epithelia detect osmotic perturbations to the luminal surface in vitro. This ability to detect and respond to changes in surface composition may be important in homeostatic regulation of vocal fold surface fluid during osmotic perturbations in respiration and phonation.
Effects of Intensive Voice Treatment (the Lee Silverman Voice Treatment [LSVT]) on Vowel Articulation in Dysarthric Individuals With Idiopathic Parkinson Disease: Acoustic and Perceptual Findings
Authors: Sapir Shimon , Spielman Jennifer L. , Ramig Lorraine O. , Story Brad H. , Fox Cynthia
Published: August 2007

Purpose

To evaluate the effects of intensive voice treatment targeting vocal loudness (the Lee Silverman Voice Treatment [LSVT]) on vowel articulation in dysarthric individuals with idiopathic Parkinson’s disease (PD).

Method

A group of individuals with PD receiving LSVT (
n
= 14) was compared to a group of individuals with PD not receiving LSVT (
n
= 15) and a group of age-matched healthy individuals (
n
= 14) on the variables vocal sound pressure level (VocSPL); various measures of the first (F1) and second (F2) formants of the vowels /i/, /u/, and /a/; vowel triangle area; and perceptual vowel ratings. The vowels were extracted from the words
key,
stew,
and
Bobby
embedded in phrases. Perceptual vowel rating was performed by trained raters using a visual analog scale.

Results

Only VocSPL, F2 of the vowel /u/ (F2u), and the ratio F2i/F2u significantly differed between patients and healthy individuals pretreatment. These variables, along with perceptual vowel ratings, significantly changed (improved) in the group receiving LSVT only.

Conclusion

These results, along with previous findings, add further support to the generalized therapeutic impact of intensive voice treatment on orofacial functions (speech, swallowing, facial expression) and respiratory and laryngeal functions in individuals with PD.
Effects of Short- and Long-Term Changes in Auditory Feedback on Vowel and Sibilant Contrasts
Authors: Lane Harlan , Matthies Melanie L. , Guenther Frank H. , Denny Margaret , Perkell Joseph S. , Stockmann Ellen , Tiede Mark , Vick Jennell , Zandipour Majid
Published: August 2007

Purpose

To assess the effects of short- and long-term changes in auditory feedback on vowel and sibilant contrasts and to evaluate hypotheses arising from a model of speech motor planning.

Method

The perception and production of vowel and sibilant contrasts were measured in 8 postlingually deafened adults prior to activation of their cochlear implant speech processors, 1 month postactivation, and 1 year postactivation. Measures were taken postactivation both with and without auditory feedback. Contrast measures were also made for a group of speakers with reportedly normal hearing speaking with masked and unmasked auditory feedback.

Results

Vowel and sibilant contrasts, measured in the absence of auditory feedback after 1 month of prosthesis use, were diminished compared with their values measured before prosthesis. Contrasts measured in the absence of auditory feedback after 1 year’s experience with the prosthesis were increased compared with their values after 1 month’s experience. In both time samples, contrasts were enhanced when auditory feedback was restored.

Conclusion

The provision of prosthetic hearing to postlingually deafened adults impaired their phonemic contrasts at first, as their auditory feedback had novel characteristics. Once auditory feedback became recalibrated with prosthesis use, it could, in turn, revise feedforward commands that control the contrasts in its absence.