bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Characterization of a Novel Ruthenium Sensitizer with a Hexylthiophene-functionalized Terpyridine Ligand for Dye-sensitized Solar Cells
Authors: Ozawa Hironobu , Yamamoto Yasuyuki , Fukushima Kei , Yamashita Satoshi , Arakawa Hironori
Published: May 2013

A novel ruthenium sensitizer TUS-25 with a hexylthiophene-functionalized terpyridine ligand has been synthesized to improve the light-absorption ability of terpyridine-based ruthenium sensitizers. The incident photon-to-current conversion efficiency of the DSC with TUS-25 at around 400 nm was increased greatly by the introduction of two hexylthiophene units. The DSC with TUS-25 showed 7.5% conversion efficiency under AM 1.5 (100 mW cm−2) irradiation.
Comparative transcriptome analysis of small noncoding RNAs in different stages of Trypanosoma brucei
Authors: Zheng Ling-Ling , Wen Yan-Zi , Yang Jian-Hua , Liao Jian-You , Shao Peng , Xu Hui , Zhou Hui , Wen Jun-Zhi , Lun Zhao-Rong , Ayala Francisco J. , Qu Liang-Hu
Published: May 2013

Trypanosoma brucei, a pathogen of human and domestic animals, is an early evolved parasitic protozoan with a complex life cycle. Most genes of this parasite are post-transcriptionally regulated. However, the mechanisms and the molecules involved remain largely unknown. We have deep-sequenced the small RNAs of two life stages of this parasite—the bloodstream form and the procyclic form. Our results show that the small RNAs of T. brucei could derive from multiple sources, including NATs (natural antisense transcripts), tRNAs, and rRNAs. Most of these small RNAs in the two stages were found to share uniform characteristics. However, our results demonstrate that their variety and expression show significant differences between different stages, indicating possible functional differentiation. Dicer-knockdown evidence further proved that some of the small interfering RNAs (siRNAs) could regulate the expression of genes. Based on the genome-wide analysis of the small RNAs in the two stages of T. brucei, our results not only provide evidence to study their differentiation but also shed light on questions regarding the origins and evolution of small RNA-based mechanisms in early eukaryotes.
Fractional difference inequalities of Gronwall-Bellman type
Authors: Deekshitulu G. V. S. R. , Jagan Mohan J.
Published: May 2013

Discrete inequalities, in particular the discrete analogues of the Gronwall–Bellman inequality, have been extensively used in the analysis of nite difference equations. The aim of the present paper is to establish some fractional difference inequalities of Gronwall–Bellman type which provide explicit bounds for the solutions of fractional difference equations.
Double sequences of interval numbers defined by Orlicz functions
Authors: Esi Ayhan
Published: May 2013

We define and study λ2-convergence of double sequences of interval numbers dened by Orlicz function and λ2-statistical convergence of double sequences of interval numbers. We also establish some inclusion relations between them.
A study on hypersurface of complex space form
Authors: Bagewadi C. S. , Bharathi M. C.
Published: May 2013

We show that quasi-umbilical, generalized quasi-umbilical, super quasi-umbilical hypersurfaces of a complex space form are quasi-Einstein, mixed generalized quasi-Einstein and mixed super quasi-Einstein manifolds, respectively. We also prove that a Bochner at space of generalized complex space form is an Einstein manifold.
Slight extensions of some theorems on the rate of pointwise approximation of functions from some subclasses of Lp
Authors: Krasniqi Xhevat Z.
Published: May 2013

In this paper we prove some results on the rate of pointwise approximation of functions by means of some matrix transformations related to the partial sums of a Fourier series, removing the assumptions that entries of the considered matrix belong to the classes RBV S or HBV S. In fact, with weaker assumptions, our results give better degrees than those obtained previously. Moreover, some results that have been obtained earlier follow from our results as special cases. Finally, we present some theorems of such type involving the so-called γRBV S or γHBV S classes of numerical sequences.
Czwarte rozważania nad Słowami prawnymi w rzeczy sobie podobnymi Bartłomieja Groickiego
Authors: Zajda Aleksander
Published: May 2013

Fourth considerations on Bartłomiej Groicki’s Słowa prawne w rzeczy sobie podobne

Starting with B. Groicki’s Słowa prawne w rzeczy sobie podobne (1567), the paper collects and discusses lexis in the field of legal and judicial procedure. First, the history of the field procedura ‘procedure’ is briefly presented from Old Polish to modern times, and then the history of the field dilatio (‘adjorunment’) is discussed in more detail. In the Old Polish period, the most common names in the field dilatio were odwłoka, fryszt, odkład, and also several deverbal derivatives in -anie, -enie (e.g. odkładanie, odwleczenie, przewleczenie), which were however rarely written down in the sources. In the 16th c., this type becomes relatively popular, but the frequency of specific names is also very low at that time; the names odwłoka, przewłoka and zwłoka are much more common. From the second half of the 16th till the end of the 18th c., the centre of the field is dominated by dilatio, a loan word from Latin. In mid-18th c. the name odroczenie appears as an innovation, rare at first but gradually ousting the foreign dylacja and beginning to reign supreme.
Media, Aggregators, and the Link Economy: Strategic Hyperlink Formation in Content Networks
Authors: Dellarocas Chrysanthos , Katona Zsolt , Rand William
Published: May 2013

A defining property of the World Wide Web is a content site's ability to place virtually costless hyperlinks to third-party content as a substitute or complement to its own content. Costless hyperlinking has enabled new types of players, usually referred to as content aggregators, to successfully enter content ecosystems, attracting traffic and revenue by hosting links to the content of others. This, in turn, has sparked a heated controversy between content creators and aggregators regarding the legitimacy and costs/benefits of uninhibited free linking. To our knowledge, this work is the first to model the complex interplay between content and links in settings where a set of sites compete for traffic. We develop a series of analytical models that distill how hyperlinking affects the (a) incentives of content nodes to produce quality content versus link to third-party content, (b) profits of the various stakeholders, (c) average quality of content that becomes available to consumers, and (d) impact of content aggregators. Our results provide a nuanced view of the so-called link economy, highlighting both the beneficial consequences and the drawbacks of free hyperlinks for content creators and consumers.

This paper was accepted by Lorin Hitt, information systems.
Television Advertising and Online Search
Authors: Joo Mingyu , Wilbur Kenneth C. , Cowgill Bo , Zhu Yi
Published: May 2013

Despite a 20-year trend toward integrated marketing communications, advertisers seldom coordinate television and search advertising campaigns. We find that television advertising for financial services brands increases both the number of related Google searches and searchers' tendency to use branded keywords in place of generic keywords. The elasticity of a brand's total searches with respect to its TV advertising is 0.17, an effect that peaks in the morning. These results suggest that practitioners should account for cross-media effects when planning, executing, and evaluating both television and search advertising campaigns.

This paper was accepted by Pradeep Chintagunta, marketing.
Should Managers Use Team-Based Contests?
Authors: Chen Hua , Lim Noah
Published: May 2013

When designing contests to motivate employees, should managers organize employees to compete in teams or as individuals? We develop a behavioral economics model that shows that if contestants are averse to being responsible for the team's loss, a team-based (TB) contest can yield higher effort than an individual-based (IB) contest. This prediction is contrary to those of standard economics models, which favor IB contests over TB contests. We test the competing predictions using laboratory economics experiments. The results show that when contestants do not know each other, average effort levels in the TB and IB contests are not different. When contestants are allowed to socialize with potential teammates before making effort decisions, TB contests yield higher effort relative to IB contests. We also show that the relative efficacy of TB contests is driven by contestants' aversion to letting their team down.

Data, as supplemental material, are available at http://dx.doi.org/10.1287/mnsc.2013.1743 .

This paper was accepted by Peter Wakker, decision analysis.
In Search of a Data-in-Once, Electronic Health Record-Linked, Multicenter Registry—
How Far We Have Come and How Far We Still Have to Go
Authors: Marsolo Keith
Published: May 2013

The learning health system is a framework in which new knowledge is translated
into general clinical practice and clinical practice serves as the engine to generate
new evidence and knowledge. One type of learning health system is an electronic health
record (EHR)-linked multicenter registry. Significant investment has been made in recent
years to spur the adoption of EHRs and to fund the creation of health information
exchanges. Yet, given this investment, are we any closer to achieving the vision of a
learning health system? What are the areas of success? What challenges remain? To answer
these questions and using an EHR-linked multicenter registry as a model, we define a set
of requirements that need to be met in order to achieve the goals of the learning health
system. We then evaluate progress along each dimension by detailing our efforts to
create an EHR-linked multicenter registry for ImproveCareNow, a quality improvement and
research network focused on improving outcomes for children with inflammatory bowel
disease (IBD).
Crystal structure of 5',7'-dibromo-1'-(2-bromoethyl)spiro[[1,3]dioxolane- 2,3'-indolin]-2'-one, C12H10Br3NO3
Authors: Ma Li , Li Ai-Min , Wan Chong-Qing , Cao Sheng-Li
Published: May 2013

C12H10Br3NO3, orthorhombic, Pbca (no. 61), a = 12.942(2) Å, b = 10.304(2) Å, c = 21.527(3) Å, V = 2870.5 Å3, Z = 8, Rgt(F) = 0.0385, wRref(F2) = 0.0868, T = 296 K.
Mitotane levels predict the outcome of patients with adrenocortical carcinoma treated adjuvantly following radical resection
Authors: Terzolo M , Baudin A E , Ardito A , Kroiss M , Leboulleux S , Daffara F , Perotti P , Feelders R A , deVries J H , Zaggia B , De Francia S , Volante M , Haak H R , Allolio B , Al Ghuzlan A , Fassnacht M , Berruti A
Published: May 2013

Context

Mitotane plasma concentrations ≥14 mg/l have been shown to predict tumor response and better survival in patients with advanced adrenocortical carcinoma (ACC). A correlation between mitotane concentrations and patient outcome has not been demonstrated in an adjuvant setting.

Objective

To compare recurrence-free survival (RFS) in patients who reached and maintained mitotane concentrations ≥14 mg/l vs patients who did not.

Design and setting

Retrospective analysis at six referral European centers.

Patients

Patients with ACC who were radically resected between 1995 and 2009 and were treated adjuvantly with mitotane targeting concentrations of 14–20 mg/l.

Main outcome measures

RFS (primary) and overall survival (secondary).

Results

Of the 122 patients included, 63 patients (52%) reached and maintained during a median follow-up of 36 months the target mitotane concentrations (group 1) and 59 patients (48%) did not (group 2). ACC recurrence was observed in 22 patients of group 1 (35%) and 36 patients in group 2 (61%). In multivariable analysis, the maintenance of target mitotane concentrations was associated with a significantly prolonged RFS (hazard ratio (HR) of recurrence: 0.418, 0.22–0.79; P=0.007), while the risk of death was not significantly altered (HR: 0.59, 0.26–1.34; P=0.20). Grades 3–4 toxicity was observed in 11 patients (9%) and was managed with temporary mitotane discontinuation. None of the patients discontinued mitotane definitively for toxicity.

Conclusions

Mitotane concentrations ≥14 mg/l predict response to adjuvant treatment being associated with a prolonged RFS. A monitored adjuvant mitotane treatment may benefit patients after radical removal of ACC.
A novel shift in estrogen receptor expression occurs as estradiol suppresses inflammation-associated colon tumor formation
Authors: Armstrong Cameron M , Billimek Autumn R , Allred Kimberly F , Sturino Joseph M , Weeks Brad R , Allred Clinton D
Published: May 2013

Postmenopausal women on estrogen replacement therapy (ERT) have a reduced risk of developing colon cancer compared with postmenopausal women not on ERT, suggesting a role for estradiol (E2) in protection against this disease. To determine whether E2protects against inflammation-associated colon cancer when administered following the initiation of colonic DNA damage, in this study, we implanted E2-containing pellets into mice after co-treatment with azoxymethane and two rounds of dextran sulfate sodium (DSS). Wild-type (WT) E2-treated mice had reduced numbers and average area of adenocarcinomas compared with the control mice. These effects were lost in estrogen receptor-β (Erβ(Esr2)) knockout mice. Surprisingly, apoptosis was reduced and cell proliferation was increased in sections from tumors of the WT E2mice compared with the WT control mice. These findings are probably due, in part, to a reduction in ERβ expression in colonic epithelial cells as the cells progressed from a non-malignant to a cancerous state as enhanced apoptosis was observed in normal colonocytes expressing higher levels of ERβ. Furthermore, epithelial cells within the tumors had dramatically increased ERα mRNA and protein expression compared with the non-diseased mice. We conclude that while E2treatment resulted in an overall suppression of colonic adenocarcinoma formation, reduced ERβ expression accompanied by enhanced ERα expression caused an altered colonocyte response to E2treatment compared with the earlier stages of colon cancer development. These data are the first examples of decreased ERβ expression concurrent with increased ERα expression as a disease develops and highlight the importance of understanding the timing of E2exposure with regard to the prevention of inflammation-associated colon cancer.
DKK3 is a potential tumor suppressor gene in papillary thyroid carcinoma
Authors: Yin De-tao , Wu Wenxun , Li Mingchuang , Wang Qi-en , Li Hongqiang , Wang Yongfei , Tang Yifeng , Xing Mingzhao
Published: May 2013

The expression of the Dickkopf homolog 3 (DKK3) gene is downregulated in some human cancers, suggesting a possible tumor suppressor role of this gene. The role and regulation ofDKK3in thyroid cancer have not been examined. In this study, we explored the relationship of promoter methylation with the inactivation ofDKK3and tumor behaviors in papillary thyroid carcinoma (PTC). We used methylation-specific PCR and RT-PCR to examine the promoter methylation and expression ofDKK3and tumor characteristics. We found mRNA expression ofDKK3in 44.9% of the PTC tissue samples vs 100% of the matched normal thyroid tissue samples (P<0.01). In contrast, an opposite distribution pattern ofDKK3gene methylation was observed; specifically, 38.8% of the PTC tissue samples vs 0% of the matched normal thyroid tissue samples harboredDKK3methylation. An inverse correlation between the promoter methylation and mRNA expression ofDKK3in PTC tissue samples was also observed. Moreover, we also found an inverse correlation betweenDKK3expression and some aggressive pathological characteristics of PTC, including high TNM stages and lymph node metastasis, but a positive correlation betweenDKK3promoter hypermethylation and pathological aggressiveness of the tumor. Treatment of the PTC cell line TPC-1 with the demethylating agent 5-azaC reducedDKK3promoter methylation and enhanced its expression, establishing functionally the impact ofDKK3methylation on its expression. Our data thus for the first time demonstrate that theDKK3gene is a potential tumor suppressor gene in thyroid cancer and that aberrant promoter methylation is an important mechanism for its downregulation, which may play a role in the tumorigenesis and aggressiveness of PTC.
Summer heat stress affects prostaglandin synthesis in the bovine oviduct
Authors: Kobayashi Yoshihiko , Wakamiya Kaori , Kohka Misa , Yamamoto Yuki , Okuda Kiyoshi
Published: May 2013

Summer heat stress (HS) negatively affects reproductive functions, including prostaglandin (PG) F2α secretion in the endometrium, and decreases fertility in cattle. In the present study, we examined the effects of elevated temperatures on PG synthesis in oviductal epithelial cells. The epithelial cells obtained from the ampulla and isthmus of the oviduct were incubated at various temperatures (38.5, 39.5, 40.0, and 40.5 °C) for 24 h. In the ampulla, PGE2 concentration was higher at 40.5 °C than at 38.5 °C, while PGF2α production was not affected by the temperatures in this range. The expressions of microsomal PGE synthase 1 (PTGES (mPGES1)), cytosolic PGES (PTGES3 (cPGES)), and heat shock protein 90 (HSP90AA1 (HSP90)) mRNAs and proteins were higher at 40.5 °C than at 38.5 °C in the ampullary epithelial cells. Seasonal changes in the expressions of PGES and HSP90AA1 mRNAs in oviductal tissues were also investigated. The expressions of PTGES3 and HSP90AA1 mRNAs were higher in the ampullary tissues in summer than in winter. In summary, elevated temperatures stimulated PGE2 production in the ampullary oviduct by increasing the expressions of PGESs and HSP90AA1, which can activate cPGES. The overall results suggest that HS upsets PG secretions and reduces oviductal smooth muscle motility, which in turn could decrease gamete/embryo transport through the oviduct.
Aberrant expression and regulation of NR2F2 and CTNNB1 in uterine fibroids
Authors: Zaitseva Marina , Holdsworth-Carson Sarah J , Waldrip Luke , Nevzorova Julia , Martelotto Luciano , Vollenhoven Beverley J , Rogers Peter A W
Published: May 2013

Uterine fibroids are the most common benign tumour afflicting women of reproductive age. Despite the large healthcare burden caused by fibroids, there is only limited understanding of the molecular mechanisms that drive fibroid pathophysiology. Although a large number of genes are differentially expressed in fibroids compared with myometrium, it is likely that most of these differences are a consequence of the fibroid presence and are not causal. The aim of this study was to investigate the expression and regulation of NR2F2 and CTNNB1 based on their potential causal role in uterine fibroid pathophysiology. We used real-time quantitative RT-PCR, western blotting and immunohistochemistry to describe the expression of NR2F2 and CTNNB1 in matched human uterine fibroid and myometrial tissues. Primary myometrial and fibroid smooth muscle cell cultures were treated with progesterone and/or retinoic acid (RA) and sonic hedgehog (SHH) conditioned media to investigate regulatory pathways for these proteins. We showed that NR2F2 and CTNNB1 are aberrantly expressed in fibroid tissue compared with matched myometrium, with strong blood vessel-specific localisation. Although the SHH pathway was shown to be active in myometrial and fibroid primary cultures, it did not regulateNR2F2orCTNNB1mRNA expression. However, progesterone and RA combined regulatedNR2F2mRNA, but notCTNNB1, in myometrial but not fibroid primary cultures. In conclusion, we demonstrate aberrant expression and regulation of NR2F2 and CTNNB1 in uterine fibroids compared with normal myometrium, consistent with the hypothesis that these factors may play a causal role uterine fibroid development.
Refusing Treatment
Authors: Frenkel Moshe
Published: May 2013

The number of patients that decline conventional cancer treatment is substantial enough to warrant close attention. Effective patient-doctor communication is crucial in addressing this challenge.
Briefing: Pianc UK
Authors: Haigh Greg
Published: May 2013

Pianc is a professional organisation in which those involved with the design, construction and management of waterborne transport infrastructure around the world, join forces to provide expert advice on cost-effective, reliable and sustainable facilities. The organisation was established to facilitate the growth of waterborne transport in 1885. Its areas of interest cover ports, inland waterways and the coastal zone. Members include national government bodies and public authorities, corporations and individuals.
Statistical patterns in tropical tree cover explained by the different water demand of individual trees and grasses
Authors: Bertram Jason , Dewar Roderick C.
Published: May 2013

Tree cover varies enormously across tropical ecosystems—from arid savannas to closed rain forests—and yet a general predictive theory of tropical tree cover remains elusive. Here we use the maximum‐entropy method to predict the most likely sample frequency distribution of ecosystems with different tree and grass fractional cover if balance between water supply and demand were the dominant constraint on community assembly. Assuming a hierarchy of individual plant water demand in which trees require more water than grasses, we reproduce observed trends in the means and the upper and lower limits of tropical tree and grass cover across the entire spectrum of tropical ecosystem water supply. Finer details not captured by our predictions indicate the influence of additional factors, such as disturbance. Our results challenge the view that tropical tree–grass coexistence is largely sustained by disturbances in moist environments (“unstable” coexistence) with water supply playing a dominant role only in arid conditions (“stable” coexistence). More generally, they suggest that macroecological patterns can be understood and predicted as the most likely outcome of a large number of stochastic processes being played out within a relatively small number of ecological constraints.
Development of Best Turfgrass Management Practices Using the DAYCENT Model
Authors: Zhang Yao , Qian Yaling , Mecham Brent , Parton William J.
Published: May 2013

To predict the best management practices for Kentucky bluegrass (Poa pratensis L.) lawns in Colorado, the DAYCENT ecosystem model was parameterized and applied on a turfgrass ecosystem. In this study, field‐measured data on clipping yields, leaf N content, evapotranspiration (ET), deep percolation, nitrate leaching, and soil temperature from a 3‐yr lysimeter study were used for parameterization and validation. The simulation result for clipping yield was improved compared to the monthly time step CENTURY ecosystem model, with correlation coefficient (r) increased from −0.32 to 0.74. The prediction of ET and deep percolation was acceptable for the 3 yr. The long‐term irrigation and fertilization effects on Kentucky bluegrass biomass and soil C and N were also examined. We predicted a 50% reduction in the annual net production as irrigation decreases from 100% potential evapotranspiration (PET) to 60% PET in this semiarid region. The simulation result suggests that the annual fertilization rates should be gradually reduced for both moderately and highly managed lawns with increasing age of the turfgrass stand.
Simulated Impacts of Crop Residue Removal and Tillage on Soil Organic Matter Maintenance
Authors: Dalzell Brent J. , Johnson Jane M. F. , Tallaksen Joel , Allan Deborah L. , Barbour Nancy W.
Published: May 2013

Cellulosic biofuel production may generate new markets and revenue for farmers. However, residue removal may cause environmental problems such as soil erosion and soil organic matter (SOM) loss. The objective of this study was to determine the amounts of residue necessary for SOM maintenance under different tillage and residue removal scenarios for corn–soybean [Zea mays L.–Glycine max (L.) Merr.] and continuous corn rotations for a site in west‐central Minnesota. We employed a process‐based model (CQESTR) to evaluate management practices and quantify SOM changes over time. Results showed that conventional tillage resulted in SOM loss regardless of the amount of residue returned. Under no‐till, residue amount was important in determining SOM accumulation or depletion. For the upper 30 cm of soil, average annual rates of 3.65 and 2.25 Mg crop residue ha–1 yr–1 were sufficient to maintain SOM for corn–soybean and continuous corn rotations, respectively. Soil OM in soil layers below 30 cm was predicted to decrease in all scenarios as a result of low root inputs. When considered over the upper 60 cm (maximum soil depth sampled), only continuous corn with no‐till was sufficient to maintain SOM. Results from this work are important because they show that, for these management scenarios, no‐till management is necessary for SOM maintenance and that determining whether SOM is accumulating or declining depends on the soil depth considered. At current yields observed in this study area, only continuous corn with no‐till may generate enough residue to maintain or increase SOM.
Changes in Latvian river discharge regime at the turn of the century
Authors: Apsīte Elga , Rudlapa Ilze , Latkovska Inese , Elferts Didzis
Published: May 2013

The study deals with turn-of-the-century changes in the total annual river runoff distribution and high and low flows in Latvia, covering river basins within four hydrological districts which vary according to size and physiographical conditions. Mathematical statistical methods were applied in the analysis of river discharge data series for two study periods of 1951–2009 and 1881–2009. The present results confirm the basic statement concerning the Baltic countries that major significant changes in river runoff during the last two decades have occurred between spring (decrease) and winter (increase) seasons. Mostly insignificant changes in summer runoff and significant/insignificant changes in autumn runoff were found. Analysis shows that a statistically significant trend of increase in low flow for the cold period and a significant trend of decrease in the high discharge and coefficient d of uneven runoff distribution were detected. Changes in river hydrological regime are mainly caused by changes in large-scale atmospheric circulation processes following climate warming, which has taken place. Latvian river hydrography has therefore changed and become more similar to Western European rivers.
Spatial scale effects on model parameter estimation and predictive uncertainty in ungauged basins
Authors: Hughes Denis A. , Kapangaziwiri Evison , Tanner Jane
Published: May 2013

The most appropriate scale to use for hydrological modelling depends on the model structure, the purpose of the results and the resolution of available data used to quantify parameter values and provide the climatic forcing. There is little consensus amongst the community of model users on the appropriate model complexity and number of model parameters that are needed for satisfactory simulations. These issues are not independent of modelling scale, the methods used to quantify parameter values, nor the purpose of use of the simulations. This paper reports on an investigation of spatial scale effects on the application of an approach to quantify the parameter values (with uncertainty) of a rainfall-runoff model with a relatively large number of parameters. The quantification approach uses estimation equations based on physical property data and is applicable to gauged and ungauged basins. Within South Africa the physical property data are available at a finer spatial resolution than is typically used for hydrological modelling. The results suggest that reducing the model spatial scale offers some advantages. Potential disadvantages are related to the need for some subjective interpretation of the available physical property data, as well as inconsistencies in some of the parameter estimation equations.
A Canadian viewpoint on data, information and uncertainty in the context of prediction in ungauged basins
Authors: Spence C. , Burn D. H. , Davison B. , Hutchinson D. , Ouarda T. B. M. J. , St-Hilaire A. , Weber F. , Whitfield P. H.
Published: May 2013

The quality (i.e. the degree of uncertainty that results from the interpretation and analysis) of information dictates its value for decision making. There has been much progress towards improving information on the water budgets of ungauged basins by improving knowledge, tools and techniques during the Prediction in Ungauged Basins (PUB) initiative. These improvements, at least in Canada, have come through efforts in both hydrological process and statistical hydrology research. This paper is a review of some recent Canadian PUB efforts to use data to generate information and reduce uncertainty about the hydrological regimes of ungauged basins. The focus is on the Canadian context and the problems it presents, but the lessons learned are applicable to other countries with similar challenges. With a large land mass that is relatively poorly gauged, novel approaches have had to be developed to extract the most information from the available data. It can be difficult in Canada to find gauged or research basins sufficiently similar to ungauged sites of interest that contain the data required to force either statistical or deterministic models. Many statistical studies have improved information or at least an understanding of the quality of that information, of ungauged basin streamflow regimes using innovative regression-based approaches and pooled frequency analysis. Hydrological process research has reduced knowledge uncertainty, particularly in regard to cold regions processes, and this situation has led to the development of new algorithms that are reducing predictive uncertainty. There remains much to do. Current progress has created an opportunity to better integrate statistical and deterministic models via data assimilation of regionalization model estimates and those from coupled atmospheric-hydrological models. Aspects of such a modelling system could also provide more robust uncertainty analyses than traditional approaches.
Evaluation of remotely sensed snow cover product in Central Asia
Authors: Gafurov A. , Kriegel D. , Vorogushyn S. , Merz B.
Published: May 2013

Central Asian countries depend highly on water resources from snow and glacier melt, which has to be studied thoroughly to estimate water availability. However, the observation network in Central Asia is poor to carry out such studies in detail. Observations from space using remote sensing techniques might fill this observation gap, which needs to be validated. Therefore, this study evaluates the Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow cover product in Central Asia. For the evaluation, in situ snow depth data from 30 meteorological stations and higher resolution Landsat data are used. The results show an overall snow agreement between MODIS and ground observations of 93.1 and 92.7% for MODIS Terra and MODIS Aqua snow products, respectively. The agreement between MODIS and Landsat is 91.9% when considering snow and land agreements. The snow fraction product from MODIS is also validated using Landsat data, and varying accuracies are obtained. The main disadvantage of the MODIS snow cover product are the cloud induced gaps. Therefore, cloud covered pixels are eliminated using the ModSnow algorithm. Using the in situ data, the snow agreement of cloud removed snow cover data is checked, and an accuracy of 84.4% is achieved.
Evaluating hydrometric networks for prediction in ungauged basins: a new methodology and its application to England and Wales
Authors: Hannaford J. , Holmes M. G. R. , Laizé C. L. R. , Marsh T. J. , Young A. R.
Published: May 2013

Flow estimates for ungauged catchments are often derived through regionalisation methods, which enable data transfer from a pool of hydrologically similar catchments with existing gauging stations (i.e., pooling-groups). This paper presents a methodology for indexing the utility of gauged catchments within widely used pooling-group methodologies for high and low flow estimation; this methodology is then used as the basis for a network evaluation strategy. The utility of monitoring stations is assessed using catchment properties and a parallel, but independent, appraisal of the quality of gauging station data, which considers hydrometric performance, anthropogenic disturbances and record length. Results from the application of the method to a national network of over 1,100 gauging stations in England and Wales are presented. First, the method is used to appraise the fitness for purpose of the network for regionalisation. The method is then used to identify gauges which monitor catchments with high potential for regionalisation, but which are deficient in terms of data quality – where upgrades in hydrometric performance would yield the greatest benefits. Finally, gauging stations with limited value for regionalisation, given the pooling-group criteria employed, are identified. Alongside a wider review of other uses of the network, this analysis could inform a judicious approach to network rationalisation.
Impact of uncertainties in discharge determination on the parameter estimation and performance of a hydrological model
Authors: van den Tillaart Sander P. M. , Booij Martijn J. , Krol Maarten S.
Published: May 2013

Uncertainties in discharge determination may have serious consequences for hydrological modelling and resulting discharge predictions used for flood forecasting, climate change impact assessment and reservoir operation. The aim of this study is to quantify the effect of discharge errors on parameters and performance of a conceptual hydrological model for discharge prediction applied to two catchments. Six error sources in discharge determination are considered: random measurement errors without autocorrelation; random measurement errors with autocorrelation; systematic relative measurement errors; systematic absolute measurement errors; hysteresis in the discharge–water level relation and effects of an outdated discharge–water level relation. Assuming realistic magnitudes for each error source, results show that systematic errors and an outdated discharge–water level relation have a considerable influence on model performance, while other error sources have a small to negligible effect. The effects of errors on parameters are large if the effects on model performance are large as well and vice versa. Parameters controlling the water balance are influenced by systematic errors and parameters related to the shape of the hydrograph are influenced by random errors. Large effects of discharge errors on model performance and parameters should be taken into account when using discharge predictions for flood forecasting and impact assessment.
A simple model to separately simulate point and diffuse nutrient signatures in stream flows
Authors: Slaughter Andrew R. , Hughes Denis A.
Published: May 2013

A simple model has been developed to simulate the relationships between stream flow and point and diffuse nutrient concentrations. The point source component is based on a mechanistic approach (including uncertainty), while the diffuse component relies on a statistical regression model. The model is explained and its application illustrated using flow and nutrient data from the South African Department of Water Affairs national monitoring database. The study sites represent a wide range of different combinations of point and diffuse source contributions to the total nutrient signature. The model has been successfully calibrated against the observed data and the study concludes that the point source component offers opportunities for use as a scenario assessment management tool, largely related to its mechanistic basis. However, further research is required to link the parameters of the diffuse source model to diffuse load causative factors so that the model can be used effectively in un-gauged situations or to assess management scenarios.
A comparison of rainfall-runoff modelling approaches for estimating impacts of rural land management on flood flows
Authors: Bulygina Nataliya , McIntyre Neil , Wheater Howard
Published: May 2013

There is a requirement for predictive tools to assist in land management and flood risk planning, and a variety of tools have been proposed recently. We compare four tools developed under various UK research programmes. The strengths and limitations of the tools are reviewed, model performances on historic data are assessed, and the methods are applied to estimating flood flows of 5- and 10-year return periods, and flow peaks under both recent land management conditions and speculative scenarios (grazing intensification and tree planting), using the Pontbren catchment, UK as a case study. Overall, the models agree on the direction of change, so that heavy grazing increases, and afforestation and tree strips decrease the flood flows. However, the estimated effects vary significantly between methods. It is concluded that method selection needs to carefully consider the type and scale of land management scenario being examined, and the sources of data available to support the modelling. Using an ensemble of suitable models is proposed as a useful way to represent a multi-expert opinion and to characterise the structural error associated with a single model.
Development and validation of a GC–MS method for the evaluation of 17 endocrine disruptor compounds, including phytoestrogens and sitosterol, in coastal waters – their spatial and seasonal levels in Porto costal region (Portugal)
Authors: Rocha Maria João , Cruzeiro Catarina , Rocha Eduardo
Published: May 2013

A gas chromatography with mass spectrometric detection (GC–MS) method was developed and optimized for the determination of 17 endocrine disrupting compounds (EDCs) in coastal water samples. The evaluated EDCs were from different origins and included estrogens, bisphenol A, alkylphenolethoxylates, alkylphenols, phytoestrogens and sitosterol (SITO). The EDCs were extracted from samples using Oasis HLB (Hydrophilic–Lipophilic Balance) cartridges and derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) added with 1% trimethylchlorosilane (TMCS). The validation parameters revealed that this method was highly specific for all assayed compounds (>99%) and the linearity of the calibration curves showed a correlation higher than 0.99. The detection limits were at low ng/L level and the recovery rates were higher than 70%. The performance of the method was checked using coastal water samples taken every 2 months during 2009–2010 from the Douro River estuary and the Porto coastline (Portugal). These data revealed that approximately 98.0% of the analyzed compounds showed levels above their limits of detection (LODs). The measured estrogens (2–20 ng/L) and industrial pollutants (up to 1.1 μg/L) were in biologic hazardous concentrations. Besides, a clear seasonal pattern of fluctuation was established for phytoestrogens and SITO. The physicochemical data, namely the amounts of nitrates, nitrites and phosphorous, confirmed the low water quality of this area.
Microbial water quality of recreational lakes near Tbilisi, Georgia
Authors: Jaiani Ekaterine , Kokashvili Tamar , Mitaishvili Nino , Elbakidze Tinantin , Janelidze Nino , Lashkhi Nino , Kalandadze Rusudan , Mikashavidze Eteri , Natroshvili Gulnara , Whitehouse Chris A. , Huq Anwar , Tediashvili Marina
Published: May 2013

Microbial safety of recreational water is one of the major human public health issues in developing countries. Three water bodies, the Tbilisi Sea, Kumisi and Lisi lakes, in the South Caucasus region near Tbilisi, Georgia, were monitored in 2006–2009 to determine microbiological quality using standard methods. Microbial pollution indicators were determined in parallel with phytoplankton abundance and measurement of a number of physical–chemical parameters. Kumisi Lake, a brackish water body in an active agricultural area, appeared to be the most polluted, whereas the Tbilisi Sea, a freshwater reservoir was the least polluted. High values for fecal indicators in all three lakes in summer and early autumn were revealed. In our study, total enterococci counts (TEC) appeared to be a better indicator than either fecal or total coliform counts for the evaluation of fresh and brackish microbial water quality. We found significant correlation between total Vibrio counts and TEC for all three water bodies. Prevalence of somatic coliphages and V. cholerae-specific phages as additional water pollution indicator significantly correlated with abundance of the host bacteria. Particular phytoplankton groups in the lakes responded to the changes of fecal indicators; however, no correlation was observed between dominant zooplankton taxonomic groups and microbial parameters.
Efficacy of copper–silver ionization for controlling fungal colonization in water distribution systems
Authors: Chen Chang-Hua , Lin Li-Chen , Chang Yu-Jun , Liu Chun-Eng , Soon Maw-Soan , Huang Ching-Shan
Published: May 2013

The purpose of this study was to identify the prevalence of fungal colonization in water systems and to evaluate the effect of decreasing fungal colonization by a copper–silver ionization system. Environmental samples were collected for fungal culture prospectively during a 1-year period (2011–2012) at the study hospital. A total of 392 water samples were examined from five buildings on March 1, 2011 and February 29, 2012. Fungi were isolated in 13 (3.4%) of 392 water samples from five buildings. The prevalence of fungal colonization in buildings was decreased from 4.76% (9/189) to 1.97% (4/203), a reduction of more than 40%, in pre-ionization and post-ionization treatment (p < 0.001). Thirteen (3.4%) of 392 water samples yielded fungi including Fusarium species (n = 7), Penicillium species (n = 2), Scedosporium species (n = 2), Aspergillus species (n = 1), and one unidentifiable mold. The number of isolated Fusarium species in ionized water samples (0.5% (1/203)) was statistically lower than those in nonionized (3.2% (6/189)) (p = 0.003). Our finding may determine if this ionization method can be applied for control of waterborne fungi colonization in hospital water systems.
Assessment of endocrine disruptors – DDTs and DEHP (plasticizer) in source water: a case study from Selangor, Malaysia
Authors: Veerasingam Santhi Armugam , Ali Mohd Mustafa
Published: May 2013

The presence of endocrine disruptors in source water is of great concern because of their suspected adverse effects on humans, even when present at very low levels. As the main source of potable water supply, rivers in Malaysia are highly susceptible to contamination by various endocrine disruptors originating from anthropogenic activities. In this study, the contamination levels of 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) and its metabolites and di-(2-ethylhexyl) phthalate (DEHP) in rivers of Selangor were examined using gas chromatography–mass spectrometry. Samples were collected from sites representing source water for 18 drinking water treatment plants in Selangor between July 2008 and July 2009. DDT and its metabolites were detected in only 14% of the 192 samples analysed at levels ranging from 0.6 to 14.6 ng/L. Meanwhile DEHP was detected in 96.8% of the samples at levels ranging from below quantitation level (18 ng/L) to 970 ng/L. The detected levels of DDTs and DEHP were lower than the WHO and Malaysian Guidelines for Drinking Water Quality. Data obtained from this study should also serve as a reference point for future surveillance on these endocrine disruptors.
Genomic copy concentrations of selected waterborne viruses in a slum environment in Kampala, Uganda
Authors: Katukiza A. Y. , Temanu H. , Chung J. W. , Foppen J. W. A. , Lens P. N. L.
Published: May 2013

The presence of viruses in a slum environment where sanitation is poor is a major concern. However, little is known of their occurrence and genomic copy concentration in the slum environment. The main objective of this study was to determine the genomic copy concentrations of human adenoviruses F and G, Rotavirus (RV), Hepatitis A virus (HAV), Hepatitis E virus (HEV) and human adenovirus species A,C,D,E, and F (HAdV-ACDEF) in Bwaise III, a typical slum in Kampala, Uganda. Forty-one samples from surface water, grey water and ground water were collected from 30 sampling locations. The virus particles were recovered by glass wool filtration with elution using beef extract. DNA and RNA viruses were detected by the real time quantitative polymerase chain reaction (qPCR) and the reverse transcription-qPCR (RT-qPCR), respectively. HAdV-F and G were detected in 70.7% of the samples with concentrations up to 2.65 × 101 genomic copies per mL (gc mL−1). RV and HAV were detected in 60.9% and 17.1% of the samples, respectively. The maximum concentration of RV was 1.87 × 102gc mL−1. In addition, 78% of the samples tested positive for the HAdV-ACDEF, but all samples tested negative for HEV. These new data are essential for quantitative microbial risk assessment, and for understanding the effects of environmental pollution in slums.
Reduction of bacteriophage MS2 by filtration and irradiation determined by culture and quantitative real-time RT–PCR
Authors: Lodder W. J. , van den Berg H. H. J. L. , Rutjes S. A. , Bouwknegt M. , Schijven J. F. , de Roda Husman A. M.
Published: May 2013

Molecular methods are increasingly applied for virus detection in environmental samples without rendering data on viral infectivity. Infectivity data are important for assessing public health risks from exposure to human pathogenic viruses in the environment. Here, treatment efficiencies of three (drinking) water treatment processes were estimated by quantification of the indicator virus bacteriophage MS2 with culture and real-time reverse transcription polymerase chain reaction (qRT–PCR). We studied the virus reduction by slow sand filtration at a pilot plant. No decay of MS2 RNA was observed, whereas infectious MS2 particles were inactivated at a rate of 0.1 day−1. Removal of MS2 RNA and infectious MS2 particles was 1.2 and 1.6 log10-units, respectively. Virus reduction by UV and gamma irradiation was determined in laboratory-scale experiments. The reduction of MS2 RNA based on qRT–PCR data was negligible. Reduction of infectious MS2 particles was estimated at 3.0–3.6 log10-units (UV dose up to 400 or 800 J/m2) and 4.7–7 log10-units (gamma dose up to 200 Gray). As shown in this study, estimations of viral reduction, both inactivation and removal, obtained by molecular methods should be interpreted carefully when considering treatment options to provide virus-safe drinking water. Combining culture-based methods with molecular methods may provide supplementary information on mechanisms of virus reduction.