bluuebunny/crossref_metadata_2025 huggingface dataset:
Saccharomyces cerevisiae engineered for xylose metabolism requires gluconeogenesis and the oxidative branch of the pentose phosphate pathway for aerobic xylose assimilation
Authors: Hector Ronald E. , Mertens Jeffrey A. , Bowman Michael J. , Nichols Nancy N. , Cotta Michael A. , Hughes Stephen R.
Published: June 2011

Saccharomyces strains engineered to ferment xylose using Scheffersomyces stipitis xylose reductase (XR) and xylitol dehydrogenase (XDH) genes appear to be limited by metabolic imbalances, due to differing cofactor specificities of XR and XDH. The S. stipitis XR, which uses both NADH and NADPH, is hypothesized to reduce the cofactor imbalance, allowing xylose fermentation in this yeast. However, unadapted S. cerevisiae strains expressing this XR grow poorly on xylose, suggesting that metabolism is still imbalanced, even under aerobic conditions. In this study, we investigated the possible reasons for this imbalance by deleting genes required for NADPH production and gluconeogenesis in S. cerevisiae. S. cerevisiae cells expressing the XR–XDH, but not a xylose isomerase, pathway required the oxidative branch of the pentose phosphate pathway (PPP) and gluconeogenic production of glucose‐6‐P for xylose assimilation. The requirement for generating glucose‐6‐P from xylose was also shown for Kluyveromyces lactis. When grown in xylose medium, both K. lactis and S. stipitis showed increases in enzyme activity required for producing glucose‐6‐P. Thus, natural xylose‐assimilating yeast respond to xylose, in part, by upregulating enzymes required for recycling xylose back to glucose‐6‐P for the production of NADPH via the oxidative branch of the PPP. Finally, we show that induction of these enzymes correlated with increased tolerance to the NADPH‐depleting compound diamide and the fermentation inhibitors furfural and hydroxymethyl furfural; S. cerevisiae was not able to increase enzyme activity for glucose‐6‐P production when grown in xylose medium and was more sensitive to these inhibitors in xylose medium compared to glucose. Published in 2011 by John Wiley & Sons, Ltd.
The control variational method for beams in contact with deformable obstacles
Authors: Barboteu M. , Sofonea M. , Tiba D.
Published: June 2011

We consider a mathematical model which describes the equilibrium of an elastic beam in contact with two obstacles. The contact is modeled with a normal compliance type condition in such a way that the penetration is allowed but is limited. We state the variational formulation of the problem and prove an existence and uniqueness result for the weak solution. Then, we provide an alternative approach to the model, based on the control variational method. Necessary and sufficient optimality conditions are derived, together with an approximation property. We also adapt our results to some versions of the model which describe the contact with a single obstacle. For this type of problems we present two methods of numerical approach, based on the iterative control variational method and the Newton method, respectively, and provide numerical simulations for the two algorithms.
The homogenized equations of motion for an activated elastic lamination in plane strain
Authors: Sanguinet W.C.
Published: June 2011

The equations of motion for an elastic laminar spatial‐temporal composite are investigated. It is assumed that the composite is binary, that is, it is assembled of two original constituents capable of changing (in space‐time) their material density, as well as their material stiffness. The condition of plane strain was then imposed on the composite. The paper begins by attempting to evaluate the materials' average Lagrangian (action density). In doing so, it immediately becomes apparent that expressions are needed for average momentum and stress. Both quantities are found to depend linearly on average strain and average velocity. After calculating the general Euler equations of motion, isotropy was assumed, and two additional forces (one being of a Coriolis nature) were found in the averaged equations of elastodynamics due to the presence of simultaneous change in both inertial and elastic properties of the original material constituents. The appearance of these two forces is a consequence of both dynamics and plane strain; the Coriolis type force disappears in the case of one dimensional strain that arises when longitudinal dynamic disturbances propagate along an elastic bar.
Dynamics of mechanical systems with nonlinear nonholonomic constraints – I The history of solving the problem of a material realization of a nonlinear nonholonomic constraint
Authors: Zeković D.N.
Published: June 2011

The paper brings forth a detailed analysis of the solution of the problem of the material realization of a nonlinear nonholonomic constraint (NNC). The existing models of the NNC are shown that can be classified into two groups: the first group comprises correctly realized physical models, while the second group contains the so‐called “quasinonlinear” nonholonomic constraints which in fact represent mathematical models. The correctness of the cited models is considered in detail, and the essential nature of such constraints, the basic of which is holonomic, is shown. The second group of models, i.e., the “quasinonlinear” NC (nonholonomic constraints) in fact represents the given program of motion, while the additional force, which carries out the program, has the analytical form of the reaction of the NNC. That is why are presented the models of the NNC which possess a clear physical sense, on the basis of which certain statements on the method of variation and the reaction of the NNC can be given. With regard to the clear physical sense and the nature of the models cited, the NNC that come out of them are used quite normally in the analysis of motion of such a system. The cited models, together with standard models oh nonholonomic Mechanics (sphere, disk, blade) make a group of basic nonholonomic constraints which can be classified, according to the three criteria, into certain types. Finally, it is shown that the cited model can be used for the construction of “nonholonomic chains”, both open and closed ones.
Expression and fermentation optimization of oxidized polyvinyl alcohol hydrolase in E. coli
Authors: Yang Yu , Zhang Dongxu , Liu Song , Jia Dongxu , Du Guocheng , Chen Jian
Published: June 2011

Oxidized polyvinyl alcohol (PVA) hydrolase (OPH) is a key enzyme in the degradation of PVA, suggesting that OPH has a great potential for application in textile desizing processes. In this study, the OPH gene from Sphingopyxis sp. 113P3 was modified, by artificial synthesis, for overexpression in Escherichia coli. The OPH gene, lacking the sequence encoding the original signal peptide, was inserted into pET-20b (+) expression vector, which was then used to transform E. coli BL21 (DE3). OPH expression was detected in culture medium in which the transformed E. coli BL21 (DE3) was grown. Nutritional and environmental conditions were investigated for improved production of OPH protein by the recombinant strain. The highest OPH activity measured was 47.54 U/mL and was reached after 84 h under optimal fermentation conditions; this level is 2.64-fold higher that obtained under sub-optimal conditions. The productivity of recombinant OPH reached 565.95 U/L/h. The effect of glycine on the secretion of recombinant OPH was examined by adding glycine to the culture medium to a final concentration of 200 mM. This concentration of glycine reduced the fermentation time by 24 h and increased the productivity of recombinant OPH to 733.17 U/L/h. Our results suggest that the recombinant strain reported here has great potential for use in industrial applications.
Exploring the Role of Religiosity and Spirituality in Amniocentesis Decision‐Making Among Latinas
Authors: Seth Sarah Guerra , Goka Thomas , Harbison Andrea , Hollier Lisa , Peterson Susan , Ramondetta Lois , Noblin Sarah Jane
Published: June 2011

Given the complex array of emotional and medical issues that may arise when making a decision about amniocentesis, women may find that their spiritual and/or religious beliefs can comfort and assist their decision‐making process. Prior research has suggested that Latinas’ spiritual and/or religious beliefs directly influence their amniocentesis decision. A more intimate look into whether Latinas utilize their beliefs during amniocentesis decision‐making may provide an opportunity to better understand their experience. The overall goal of this study was to describe the role structured religion and spirituality plays in Latinas’ daily lives and to evaluate how religiosity and spirituality influences health care decisions, specifically in prenatal diagnosis. Semi‐structured interviews were conducted with eleven women who were invited to describe their religious beliefs and thoughts while considering the option of amniocentesis. All participants acknowledged the influence of religious and/or spiritual beliefs in their everyday lives. Although the women sought comfort and found validation in their beliefs and in their faith in God's will during their amniocentesis decision‐making process, results suggest the risk of procedure‐related complications played more of a concrete role than their beliefs.
Precipitation and Micellar Properties of Novel Mixed Anionic Extended Surfactants and a Cationic Surfactant
Authors: Panswad Donyaporn , Sabatini David A. , Khaodhiar Sutha
Published: June 2011

Surfactant‐modified mineral surfaces can provide both a hydrophobic coating for adsorbing organic contaminants and, in the case of ionic surfactants, a charged exterior for adsorbing oppositely charged species. This research evaluates the precipitation phase boundaries and synergistic behavior of the mixtures of carboxylate‐based anionic extended surfactants with a pyridinium‐based cationic surfactant. One cationic surfactant (cetylpyridinium chloride) and four anionic extended surfactants were studied. The anionic surfactants studied were ethoxy carboxylate extended surfactants with average carbon chain lengths of either 16 and 17 or 16 and 18 with 4 mol of a propylene oxide group and a different number of moles of an ethylene oxide group (2 and 5 mol). Precipitation phase boundaries of mixed anionic extended surfactants and cationic surfactant were evaluated to ensure that the surface tension studies are in regions without precipitate. Surface tension measurements were conducted to evaluate the critical micelle concentration of individual and mixed surfactant systems. Precipitation phase boundaries of these novel mixed surfactant systems showed greatly reduced precipitation areas as compared to a conventional mixed surfactant system which is attributed to the presence of the ethylene oxide and propylene oxide groups and resulting steric hindrances to precipitation. Moreover, it was demonstrated that the CMC of mixed surfactant systems were much lower than that of individual surfactant systems. Synergism was evaluated in the four systems studied by the β parameter which found that all systems studied exhibited synergism. From these results, these novel mixed surfactant systems can greatly increase formulation space (reduce the precipitation region) while maintaining synergism, although slightly reduced from conventional anionic‐cationic mixtures reported previously.
Characterization of Lipid Components in Two Microalgae for Biofuel Application
Authors: Wang Guang , Wang Tong
Published: June 2011

A full characterization of lipid components is critical for selecting the most suitable microalgae and for downstream processing for biofuel production. This study demonstrates extraction, quantification, and diversity of lipid components from two microalgae of different types. For total lipid quantification, three extraction methods were compared and the method of pre‐drying, dry ice‐assisted grinding, and sequential solvent extraction gave the highest total lipid recovery. For lipid class composition determination, the photosynthetic Nannochloropsis contained 37.0% polar lipids, 41.1% triacylglycerols, and 12.5% unsaponifiable matter, whereas, the heterotrophic Schizochytrium had much less polar lipids and unsaponifiable matter. Further separation and quantification showed that Nannochloropsis contained more glycolipids (37.1% of total polar lipids) than that in Schizochytrium (14.3%), while Schizochytrium contained much more phospholipids (85.7%) than that in Nannochloropsis (44.7%). The major components in unsaponifiable matter of Nannochloropsis were hydrocarbon and cholesterol (55.8 and 37.7% of the total GC quantifiable matter), which only accounted for 29.3% of total unsaponifiable matter. For Schizochytrium, 15.4% squalene, 28.9% cholesterol, and 43.2% stigmasta‐4,7,22‐trien‐3‐ol were found in its GC quantifiable matter, and the total quantified hydrocarbon and sterols accounted for 50.5% of unsaponifiable matter. The lipid compositions of the two types of microalgae are very different, therefore, processing performance, such as lipid extraction and conversion to biodiesel may be different. Similar lipid characterization for other biofuel types of microalgae needs to be made to ensure optimal biofuel processing and fuel quality.
ON SUM OF PRODUCTS AND THE ERDŐS DISTANCE PROBLEM OVER FINITE FIELDS
Authors: VINH LE ANH
Published: June 2011

For a prime powerq, let 𝔽qbe the finite field ofqelements. We show that 𝔽*q⊆d𝒜2for almost every subset 𝒜⊂𝔽qof cardinality ∣𝒜∣≫q1/d. Furthermore, ifq=pis a prime, and 𝒜⊆𝔽pof cardinality ∣𝒜∣≫p1/2(logp)1/d, thend𝒜2contains both large and small residues. We also obtain some results of this type for the Erdős distance problem over finite fields.
ORDER EMBEDDING OF A MATRIX ORDERED SPACE
Authors: KARN ANIL K.
Published: June 2011

We characterize certain properties in a matrix ordered space in order to embed it in a C*-algebra. Let such spaces be called C*-ordered operator spaces. We show that for every self-adjoint operator space there exists a matrix order (on it) to make it a C*-ordered operator space. However, the operator space dual of a (nontrivial) C*-ordered operator space cannot be embedded in any C*-algebra.
Bioavailability of phenols from a phenol-enriched olive oil
Authors: Suárez Manuel , Valls Rosa M. , Romero Maria-Paz , Macià Alba , Fernández Sara , Giralt Montse , Solà Rosa , Motilva Maria-José
Published: June 2011

Phenolic compounds are one of the main reasons behind the healthy properties of virgin olive oil (VOO). However, their daily intake from VOO is low compared with that obtained from other phenolic sources. Therefore, the intake of VOO enriched with its own phenolic compounds could be of interest to increase the daily dose of these beneficial compounds. To evaluate the effectiveness of enrichment on their bioavailability, the concentration of phenolic compounds and their metabolites in human plasma (0, 60, 120, 240 and 300 min) from thirteen healthy volunteers (seven men and six women, aged 25 and 69 years) was determined after the ingestion of a single dose (30 ml) of either enriched virgin olive oil (EVOO) (961·17 mg/kg oil) or control VOO (288·89 mg/kg oil) in a cross-over study. Compared with VOO, EVOO increased plasma concentration of the phenol metabolites, particularly hydroxytyrosol sulphate and vanillin sulphate (P < 0·05). After the consumption of VOO, the maximum concentration of these peaks was reached at 60 min, while EVOO shifted this maximum to 120 min. Despite these differences, the wide variability of results indicates that the absorption and metabolism of olive oil phenols are highly dependent on the individual.
Structure modification of a milk protein-based model food affects postprandial intestinal peptide release and fullness in healthy young men
Authors: Juvonen Kristiina R. , Karhunen Leila J. , Vuori Elisa , Lille Martina E. , Karhu Toni , Jurado-Acosta Alicia , Laaksonen David E. , Mykkänen Hannu M. , Niskanen Leo K. , Poutanen Kaisa S. , Herzig Karl-Heinz
Published: June 2011

Physico-chemical and textural properties of foods in addition to their chemical composition modify postprandial metabolism and signals from the gastrointestinal tract. Enzymatic cross-linking of protein is a tool to modify food texture and structure without changing nutritional composition. We investigated the effects of structure modification of a milk protein-based model food and the type of milk protein used on postprandial hormonal, metabolic and appetitive responses. Healthy males (n 8) consumed an isoenergetic and isovolumic test product containing either whey protein (Wh, low-viscous liquid), casein (Cas, high-viscous liquid) or Cas protein cross-linked with transglutaminase (Cas-TG, rigid gel) in a randomised order. Blood samples were drawn for plasma glucose, insulin, cholecystokinin (CCK), glucagon-like peptide 1 and peptide YY analysis for 4 h. Appetite was assessed at concomitant time points. Cas and Wh were more potent in lowering postprandial glucose than Cas-TG during the first hour. Insulin concentrations peaked at 30 min, but the peaks were more pronounced for Cas and Wh than for Cas-TG. The increase in CCK was similar for Cas and Wh in the first 15 min, whereas for Cas-TG, the CCK release was significantly lower, but more sustained. The feeling of fullness was stronger after the consumption of Cas-TG than after the consumption of Cas and Wh. The present results suggest that food structure is more effective in modulating the postprandial responses than the type of dairy protein used. Modification of protein-based food structure could thus offer a possible tool for lowering postprandial glucose and insulin concentrations and enhancing postprandial fullness.
Effects of dietary protein content and 2-hydroxy-4-methylthiobutanoic acid ordl-methionine supplementation on performance and oxidative status of broiler chickens
Authors: Swennen Quirine , Geraert Pierre-André , Mercier Yves , Everaert Nadia , Stinckens Anneleen , Willemsen Hilke , Li Yue , Decuypere Eddy , Buyse Johan
Published: June 2011

Besides its typical role as an amino acid in protein synthesis, methionine is an important intermediate in methylation reactions. In addition, it can also be converted to cysteine and hence plays a role in the defence against oxidative stress. The present study was conducted to investigate further the role ofdl-methionine (DLM) and its hydroxy analogue,dl-2-hydroxy-4-methylthiobutanoic acid (DL-HMTBA), on zootechnical performance and oxidative status of broiler chickens. Male broiler chickens were reared on two diets differing in crude protein (CP) content (low-protein, 18·3 %v.high-protein, 23·2 % CP) and were supplemented either with 0·25 % DLM or 0·25 % DL-HMTBA. Reducing the dietary protein content resulted in an impaired body weight gain (P < 0·0001). However, supplementation of DL-HMTBA to the low-protein diet partially alleviated these negative effects (P = 0·0003). This latter phenomenon could be explained by the fact that chickens fed DL-HMTBA-supplemented diets displayed a better antioxidant status as reflected in lower lipid peroxidation probably as a consequence of their higher hepatic concentrations of total and reduced glutathione compared with their DLM counterparts. On the other hand, within the high protein levels, uric acid might be an important antioxidant to explain the lower lipid peroxidation of high-protein DL-HMTBA-supplemented chickens. Hepatic methionine sulfoxide reductase-A gene expression was not significantly affected by the dietary treatments. In conclusion, the present study indicates that there are interactions between dietary protein content and supplementation of methionine analogues with respect to broiler performance and antioxidant status, also suggesting a causal link between these traits.
Large, solitary angiokeratoma in the posterior third and base of the tongue: case report
Authors: Dutta M , Ghatak S , Biswas G , Sinha R
Published: June 2011

Objective:

We present an extremely rare case of isolated angiokeratoma of the tongue.

Method:

Case report and review of related literature.

Results:

An 18-year-old, male adolescent presented with a fleshy, intermittently bleeding mass in the posterior third and base of the tongue. The lesion was initially suspected to be a lingual thyroid or haemangioma, but histopathological features were consistent with angiokeratoma. Magnetic resonance imaging revealed that the lesion extended up to the vallecula and involved the lamina propria and superficial tongue musculature. No similar lesions were found elsewhere in the body. No metabolic derangements were identified in the patient or his family. The 2.6 × 1.5 × 0.5 cm mass was excised under general anaesthesia.

Conclusion:

We present the 1st case of isolated lingual angiokeratoma in a male, the 4th such case overally, the largest ever documented. The lesion was situated in the posterior third and base of the tongue, a position not previously described.
Quality parenteral nutrition: an ideal mixed bag
Authors: White Rebecca
Published: June 2011

Professor Pennington was an advocate for quality in all aspects of nutrition support and its delivery, ensuring that the patient remained at the centre of all decisions, and that specialist artificial nutrition support was best managed by the multidisciplinary nutrition team and the education of the wider healthcare community. Within the conference theme of ‘Quality’, this commentary aims to outline drivers for and risks to aspects of quality in parenteral nutrition (PN) services. Quality is defined as a particular property or attribute associated with excellence; in the context of the provision of PN this can be translated to quality processes and standards in the assessment, prescription, preparation, administration and monitoring of PN. Quality products and services are delivered through the timely application of knowledge, competence, procedures and standards. Quality can be so easily compromised; inattention, ignorance and arrogance all play their part. PN is a high-risk therapy; the quality of its delivery should not be entirely dependent on the skills, knowledge and competence of those delivering this care but on accepted standards, procedures, communication, resource and infrastructure. Identification of key steps in the provision of PN and a review of the relevant patient safety data reveal points where safeguards can be put in place to ensure quality is not compromised. Full evaluation of standardisation, computerisation and competency-based training as risk-reduction strategies is required.
Linked indicator sets for addressing biodiversity loss
Authors: Sparks Tim H. , Butchart Stuart H. M. , Balmford Andrew , Bennun Leon , Stanwell-Smith Damon , Walpole Matt , Bates Nicholas R. , Bomhard Bastian , Buchanan Graeme M. , Chenery Anna M. , Collen Ben , Csirke Jorge , Diaz Robert J. , Dulvy Nicholas K. , Fitzgerald Claire , Kapos Valerie , Mayaux Philippe , Tierney Megan , Waycott Michelle , Wood Louisa , Green Rhys E.
Published: June 2011

The target adopted by world leaders of significantly reducing the rate of biodiversity loss by 2010 was not met but this stimulated a new suite of biodiversity targets for 2020 adopted by the Parties to the Convention on Biological Diversity (CBD) in October 2010. Indicators will be essential for monitoring progress towards these targets and the CBD will be defining a suite of relevant indicators, building on those developed for the 2010 target. Here we argue that explicitly linked sets of indicators offer a more useful framework than do individual indicators because the former are easier to understand, communicate and interpret to guide policy. A Response-Pressure-State-Benefit framework for structuring and linking indicators facilitates an understanding of the relationships between policy actions, anthropogenic threats, the status of biodiversity and the benefits that people derive from it. Such an approach is appropriate at global, regional, national and local scales but for many systems it is easier to demonstrate causal linkages and use them to aid decision making at national and local scales. We outline examples of linked indicator sets for humid tropical forests and marine fisheries as illustrations of the concept and conclude that much work remains to be done in developing both the indicators and the causal links between them.
Perceptual processing advantages for trauma-related visual cues in post-traumatic stress disorder
Authors: Kleim B. , Ehring T. , Ehlers A.
Published: June 2011

Background

Intrusive re-experiencing in post-traumatic stress disorder (PTSD) comprises distressing sensory impressions from the trauma that seem to occur ‘out of the blue’. A key question is how intrusions are triggered. One possibility is that PTSD is characterized by a processing advantage for stimuli that resemble those that accompanied the trauma, which would lead to increased detection of such cues in the environment.

Method

We used a blurred picture identification task in a cross-sectional (n=99) and a prospective study (n=221) of trauma survivors.

Results

Participants with acute stress disorder (ASD) or PTSD, but not trauma survivors without these disorders, identified trauma-related pictures, but not general threat pictures, better than neutral pictures. There were no group differences in the rate of trauma-related answers to other picture categories. The relative processing advantage for trauma-related pictures correlated with re-experiencing and dissociation, and predicted PTSD at follow-up.

Conclusions

A perceptual processing bias for trauma-related stimuli may contribute to the involuntary triggering of intrusive trauma memories in PTSD.
Spatial patterns of illegal resource extraction in Kibale National Park, Uganda
Authors: MACKENZIE CATRINA A. , CHAPMAN COLIN A. , SENGUPTA RAJA
Published: June 2011

Conservation policy typically excludes people from national parks and manages encroachment by law enforcement. However, local people continue to extract resources from protected areas by boundary encroachment and poaching. This paper quantifies the patterns of illegal resource extraction from Kibale National Park in Uganda, the demand for Park resources by communities bordering the Park, and examines whether designated resource access agreements reduce illegal extraction. Sections of the Park boundary were examined and human entry trails, wood extraction, livestock grazing, and animal poaching signs were quantified. Levels of illegal extraction were compared with the demand for and admitted illegal access to resources inside the Park, collected in a survey of households located near the Park. Extraction was also compared between villages with and without negotiated resources access agreements. The most wanted and extracted resource from the Park was wood for fuel and construction. Implementation of resource access agreements with local community associations was found to be an effective means of reducing illegal extraction, but only if the association members profited from the agreement.
Trend of hospital utilization for encephalitis
Authors: BARBADORO P. , MARIGLIANO A. , RICCIARDI A. , D'ERRICO M. M. , PROSPERO E.
Published: June 2011

Encephalitis generally results in a serious illness requiring hospitalization. The aim of this study was to describe the epidemiology of hospitalization for encephalitis in Italy, taking into account the geographical distribution, aetiology, seasonality and evolution of hospitalization rates over recent years. The mean hospitalization rate was 5·88/100 000. For most of these hospitalizations (n=13 119, 55·6%), no specific cause of encephalitis was reported. The most common aetiological category was ‘viral’, which accounted for 40·1% (n=4205) of such hospitalizations (rate 1·05/100 000). Within this category, herpes virus was the leading causative agent (n=1579, 0·39/100 000). This report highlights a significant increase of ‘viral encephalitis not otherwise specified’ (ICD-9 code 049·9)vs. a reduction of all other causes. A seasonal pattern was noted in people aged ⩾65 years in this group. Specific surveillance of encephalitis without known origin should be reinforced in order to identify the potential role of emerging pathogens and to design preventive interventions.
Prevalence and growth kinetics of Shiga toxin-producingEscherichia coli(STEC) in bovine offal products in Japan
Authors: ASAKURA H. , SAITO E. , MOMOSE Y. , EKAWA T. , SAWADA M. , YAMAMOTO A. , HASEGAWA A. , IWAHORI J. , TSUTSUI T. , OSAKA K. , MATSUSHITA T. , KAKINUMA M. , MOTOYAMA K. , HAYAMA Y. , KITAMOTO H. , IGIMI S. , KASUGA F.
Published: June 2011

Recent epidemiological data suggest a link between the consumption of bovine offal products and Shiga toxin-producingEscherichia coli(STEC) infection in Japan. This study thus examined the prevalence of STEC in various types of these foods. PCR screened 229 bovine offal products for the presence of Shiga toxin (stx) gene. Thirty-eight (16·6%) samples werestxpositive, of which eight were positive forrfbEO157and three were positive forwzyO26. Four O157 and one O26 STEC isolates were finally obtained from small-intestine and omasum products. Notably, homogenates of bovine intestinal products significantly reduced the extent of growth of O157 in the enrichment process compared to homogenates of beef carcass. As co-incubation of O157 with background microbiota complex from bovine intestinal products in buffered peptone water, in the absence of meat samples, tended to reduce the extent of growth of O157, we reasoned that certain microbiota present in offal products played a role. In support of this, inoculation of genericE. colifrom bovine intestinal products into the homogenates significantly reduced the extent of growth of O157 in the homogenates of bovine intestinal and loin-beef products, and this effect was markedly increased when these homogenates were heat-treated prior to inoculation. Together, this report provides first evidence of the prevalence of STEC in a variety of bovine offal products in Japan. The prevalence data herein may be useful for risk assessment of those products as a potential source of human STEC infection beyond the epidemiological background. The growth characteristic of STEC O157 in offal products also indicates the importance of being aware when to test these food products.
Collecting close-contact social mixing data with contact diaries: reporting errors and biases
Authors: SMIESZEK T. , BURRI E. U. , SCHERZINGER R. , SCHOLZ R. W.
Published: June 2011

The analysis of contact networks plays a major role to understanding the dynamics of disease spread. Empirical contact data is often collected using contact diaries. Such studies rely on self-reported perceptions of contacts, and arrangements for validation are usually not made. Our study was based on a complete network study design that allowed for the analysis of reporting accuracy in contact diary studies. We collected contact data of the employees of three research groups over a period of 1 work week. We found that more than one third of all reported contacts were only reported by one out of the two involved contact partners. Non-reporting is most frequent in cases of short, non-intense contact. We estimated that the probability of forgetting a contact of ⩽5 min duration is greater than 50%. Furthermore, the number of forgotten contacts appears to be proportional to the total number of contacts.
Paediatric intensive care admissions for respiratory syncytial virus bronchiolitis in France: results of a retrospective survey and evaluation of the validity of a medical information system programme
Authors: SOILLY A.-L. , FERDYNUS C. , DESPLANCHES O. , GRIMALDI M. , GOUYON J. B.
Published: June 2011

The purpose of this study was to describe the characteristics of patients with bronchiolitis admitted to a paediatric intensive care unit (PICU), and to evaluate a national registry of hospitalizations (Programme de Médicalisation des Systèmes d'Information; PMSI) as a potential source of epidemiological data. Of the 49 French PICUs invited to take part in a retrospective survey of children aged <2 years who were hospitalized during the 2005–2006 epidemic season, 24 agreed to participate. Overall, 467 children were enrolled: 75% were aged <2 months, 76% had positive respiratory syncytial virus (RSV) tests, 34·9% required non-invasive ventilation, 36·6% were mechanically ventilated, and six infants died. The main neonatal characteristics were: prematurity (31·9%), respiratory disease (16·5%), congenital heart disease (6·4%), receiving mechanical ventilation (11·6%), and bronchopulmonary dysplasia at day 28 (3·8%). For bronchiolitis episode, the kappa coefficient between the survey and PMSI data was good only for mechanical ventilation (0·63) and the death rate (0·86).
Distribution of downy mildew (Bremia lactucaeRegel) resistances in a genebank collection of lettuce and its wild relatives
Authors: van Treuren R. , van der Arend A. J. M. , Schut J. W.
Published: June 2011

Genebanks serve as a rich source of diversity that can be exploited for crop improvement. However, large numbers of accessions usually have to be evaluated to find material with the characters of interest, and therefore, enhanced trait information can facilitate the more efficient selection of accessions by users. In this study, we report on the distribution of resistances to 28 races of downy mildew among 1223 genebank accessions of cultivated lettuce (Lactuca sativaL.) and 14 related wild species. Due to modern plant breeding, the overall level of resistance of cultivars released after 1950 appears to have increased two- to three-fold compared with varieties from earlier periods. Although fully resistant reactions could be observed among the accessions of cultivated lettuce for each of the 28 investigated races, the resistance probability was more than two-fold higher on average for accessions from the wild gene pool. In general, species of the primary gene pool appeared less resistant than those of the secondary or tertiary gene pool. Probabilities for examinedLactucaspecies ranged from 0.29 forL. serriolato 1.00 forL. perenniscompared with 0.19 for cultivated lettuce, with lower overall resistance probabilities observed only forL. altaica,L. dregeanaandL. tenerrima. ForL. serriola, the closest relative of cultivated lettuce and the wild species with the highest number of examined accessions, resistance probabilities to each of the investigated downy mildew races were relatively high for populations originating from Eastern Europe and Northern Asia.
LAND REGISTRATION AND LOCAL SOCIETY IN QING CHINA: TAXATION AND PROPERTY RIGHTS IN MID-NINETEENTH CENTURY GUANGDONG
Authors: Matsubara Kentaro
Published: June 2011

This paper explores the relationship between local lineage social structure and the workings of tax registration in Qing China, through a case study providing documentary evidence of a level of precision that enables us to go beyond the findings of previous scholarship. In the first instance, it reconstructs a tax dispute where implications of the registration system come into play, based on rare records made by the taxpayers themselves. In doing so, it shows that (a) the registered “acreage” of land was in fact unrelated to any actual land whatsoever; (b) tax collection ceased to be able to rely on knowledge of the terrain and had to depend on knowing the social groups that could be held responsible for payment, while the cohesion and internal differentiation of these social groups was (in turn) underpinned by tax collection and registration; and (c) since the registration system did not permit the government to keep track of actual landholding, property rights had to be secured at the local community level. In conclusion, an attempt is made to speculate on the extent to which this specific case contributes to our knowledge of local social structure, the interactions between localities and the government, and the property regime of Qing China overall.
A simple framework for relating variations in runoff to variations in climatic conditions and catchment properties
Authors: Roderick Michael L. , Farquhar Graham D.
Published: June 2011

We use the Budyko framework to calculate catchment‐scale evapotranspiration (E) and runoff (Q) as a function of two climatic factors, precipitation (P) and evaporative demand (Eo = 0.75 times the pan evaporation rate), and a third parameter that encodes the catchment properties (n) and modifies how P is partitioned between E and Q. This simple theory accurately predicted the long‐term evapotranspiration (E) and runoff (Q) for the Murray‐Darling Basin (MDB) in southeast Australia. We extend the theory by developing a simple and novel analytical expression for the effects on E and Q of small perturbations in P, Eo, and n. The theory predicts that a 10% change in P, with all else constant, would result in a 26% change in Q in the MDB. Future climate scenarios (2070–2099) derived using Intergovernmental Panel on Climate Change AR4 climate model output highlight the diversity of projections for P (±30%) with a correspondingly large range in projections for Q (±80%) in the MDB. We conclude with a qualitative description about the impact of changes in catchment properties on water availability and focus on the interaction between vegetation change, increasing atmospheric [CO2], and fire frequency. We conclude that the modern version of the Budyko framework is a useful tool for making simple and transparent estimates of changes in water availability.
Flow to partially penetrating wells in unconfined heterogeneous aquifers: Mean head and interpretation of pumping tests
Authors: Dagan G. , Lessoff S. C.
Published: June 2011

A partially penetrating well of length Lw and radius Rw starts to pump at constant discharge Qw at t = 0 from an unconfined aquifer of thickness D. The aquifer is of random and stationary conductivity characterized by KG (geometric mean), σY2 (log conductivity variance), and I and Iv (the horizontal and vertical integral scales). The flow problem is solved under a few simplifying assumptions commonly adopted in the literature for homogeneous media: Rw/Lw ≪ 1, linearization of the free surface condition, and constant drainable porosity n. Additionally, it is assumed that Rw/I < 1 and Lw/Iv ≫ 1 (to simplify the well boundary conditions) and that a first‐order approximation in σY2 (extended to finite σY2 on a conjectural basis) is adopted. The solution is obtained for the mean head field 〈H(R, z, t)〉 and the associated water table equation. The main result of the analysis is that the flow domain can be divided into three zones for 〈H〉: (1) the neighborhood of the well R ≪ I, where 〈H〉 = (Qw/LwKA)h0(R, z, tKefuv/nD), with h0 being the zero‐order solution pertaining to a homogeneous and isotropic aquifer, KA being the conductivity arithmetic mean, and Kefuv being the effective vertical conductivity in mean uniform flow, (2) an exterior zone R ⪆ I in which H = (Qw/LwKefuh)h0(R, z, tKefuv/nD), with Kefuh being the horizontal effective conductivity, and (3) an intermediate zone in which the solution requires a few numerical quadratures, not carried out here. The application to pumping tests reveals that identification of the aquifer parameters for homogeneous and anisotropic aquifers by commonly used methods can be applied for the drawdown measured in an observation well of length LowIv (to ensure exchange of space and ensemble head averages) in the second zone in order to identify Kefuh, Kefuv, and n. In contrast, the use of the drawdown in the well (first zone) leads to an overestimation of Kefuh by the factor KA/Kefuh.
Discovery and focused study of the Chicxulub impact crater
Authors: Urrutia‐Fucugauchi Jaime , Camargo‐Zanoguera Antonio , Pérez‐Cruz Ligia
Published: June 2011

Three decades ago, a landmark paper by Alvarez et al. [1980] proposed that an asteroid impact 65.5 million years ago was the cause of the mass extinction of about 75% of species, including the dinosaurs, at the boundary between the Cretaceous and Paleogene periods (K‐Pg), formerly known as the Cretaceous‐Tertiary (K‐T) boundary. Alvarez et al. used geochemical studies on carbonate sequences from Italy, Denmark, and New Zealand to study the boundary layer, which was enriched in iridium and other platinum group elements (PGEs) at concentrations well above background levels. They associated these enrichments with the collision of an asteroid that injected large amounts of pulverized debris into the atmosphere, resulting in blockage of solar radiation, global cooling, and a shutdown of photosynthesis.
Continuous operation of spectroscopy instruments for stable isotope analysis
Authors: Zeeman Matthias J. , Tu Kevin P. , Knohl Alexander
Published: June 2011

Routine Application of Novel Stable Isotope Spectroscopy Instruments; Berkeley, California, 12 December 2010; Stable isotopes provide a tracer for biogeochemical processes and for exchange between the biosphere and atmosphere at local to global scales. Recent developments in laser spectroscopy now offer the ability to measure stable isotopes in small molecules such as water vapor and carbon dioxide in unprecedented temporal resolution (up to 10 hertz). In a meeting organized with support from the U.S. National Science Foundation–funded Biogeosphere‐Atmosphere Stable Isotope Network (BASIN), an international group consisting of researchers and manufacturers' representatives discussed the challenges of daily use of absorption spectroscopy instruments for stable isotope analysis in continuous field operation. Technological advancement in absorption spectroscopy analysis techniques tied to increased availability of affordable instruments has opened the door to new scientific opportunities and facilitates the use of stable isotope analysis by a larger group of researchers. Despite technological progress, though, stable isotope analysis still requires delicate treatment of samples and setup. Meeting participants tried to identify the key responsibilities for individual labs and the scientific community to help ensure comparability of results and prepare for future regional to global collaborative research efforts. The meeting was concluded with the recommendations below.
Middle and high school students present posters at AGU Fall Meeting
Authors: Saltzman Jennifer
Published: June 2011

While science fairs may be one way for students to learn about science, AGU takes the science fair one step further by hosting middle and high school students from the San Francisco Bay Area so they can show off their research in the professional arena. The Bright Students Training as Research Scientists (Bright STaRS) program creates a special day at the AGU Fall Meeting for budding scientists. In addition to learning the ins and outs of geoscience research by participating in data collection and analysis for their research projects, they learn the importance of communication by presenting their results. Since 2004 the AGU Bright STaRS initiative has hosted students who have worked on research projects at universities, high schools, and science learning centers. The program enables them to spend a day at the Fall Meeting and to present their research in a poster session. Each year 10–15 abstracts are submitted by about 25–40 middle and high school students for this event; in 2010 this increased to 26 abstracts and 50 students. Since its inception, more than 250 students have participated in Bright STaRS.
Murugesu Sivapalan receives 2010 Hydrologic Sciences Award: Response
Authors: Sivapalan Murugesu
Published: June 2011

Murugesu Sivapalan received the 2010 Hydrologic Sciences Award at the 2010 AGU Fall Meeting, held 13–17 December in San Francisco, Calif. The award is for outstanding contributions to the science of hydrology.
The global virtual water trade network
Authors: Tretkoff Ernie
Published: June 2011

While some countries have substantial supplies of freshwater, others need to import water to sustain their populations. Because food products contain significant amounts of water, global trade in food effectively moves water from one country to another in a “virtual water trade.” Konar et al. consider the global virtual water trade as a weighted complex network. The nations that participate in international food trade correspond to the nodes, and the links represent the flow of virtual water; weights are assigned to the links based on the volume of virtual water traded. They found that the number of trade connections follows an exponential distribution. There is a global hierarchy in which nations that trade large volumes of virtual water are more likely to link to other nations that trade large volumes of water. Several nations play a critical role in this network. For instance, the United States is the dominant exporter of virtual water, and Japan is the dominant importer. Furthermore, trade volume follows a power law relationship with the number of trade partners of each nation: The more trading partners a country has, the more virtual water it trades. The study could help in global water resource management; for instance, water‐scarce nations could consider increasing their access to virtual water resources by increasing the number of nations with which they trade food. (Water Resources Research, doi:10.1029/2010WR010307, 2011)
Zooming in on aquatic denitrification hot spots
Authors: Schultz Colin
Published: June 2011

Inorganic nitrogen is an important resource for marine and aquatic ecosystems, acting as a fertilizer for phytoplankton and aquatic plants. When nitrogen concentrations soar, algae blooms can occur. Subsequently, when the algae blooms die, their decomposition can consume most of the available dissolved oxygen, negatively affecting the ecosystem as a whole. Creeks and streams act as strong controls, regulating downstream nitrogen concentrations, and researchers have been zooming in on hyporheic zones—zones where water flows through the sediment alongside the surface water—as possible hot spots of activity in the nitrogen cycle. Using a stable isotope tracer, Zarnetske et al. tracked the evolution of a nitrogen addition as it flowed through a heavily instrumented gravel bar in Drift Creek, in Oregon. The researchers found that the gravel bar could act as either a source or a sink of inorganic nitrogen, depending on how long it took for the water to make its way through the bar. When the creek water took longer to pass through the hyporheic zone, nitrogen levels were reduced significantly through denitrification, while any water that traveled quickly could have its inorganic nitrogen concentrations increased by nitrification. The authors note that a context‐dependent effect of individual hyporheic zones on inorganic nitrogen concentrations could have important implications for attempts to estimate the effects of a watershed on the nitrogen cycle. (Journal of Geophysical Research‐Biogeosciences, doi:10.1029/2010JG001356, 2011)
Agricultural chemical export dynamics in a watershed
Authors: Tretkoff Ernie
Published: June 2011

Understanding how agricultural chemicals filter through a catchment is important for managing water quality. Using a concept of the catchment as a physicochemical filter, Guan et al. examined nitrate, phosphate, and atrazine loads in the Little Vermillion River watershed, a tile‐drained watershed in Illinois. They analyzed a 10‐year data set using mathematical signal processing to investigate spatial and temporal patterns in chemical concentrations and discharge rate. They found that export of these chemicals had a linear relationship with streamflow at annual scales—the higher the streamflow, the more these chemicals were exported from the watershed. The researchers' approach helps identify the roles of different hydrological flow paths in controlling chemical export at different spatial and temporal scales and reveals that chemical inputs overwhelm normal biogeochemical processing in these agricultural systems, leading to high long‐term average rates of export. (Water Resources Research, doi:10.1029/2010WR009997, 2011)