696 research outputs found

    Occurrence and temporal variations of TMDD in the river Rhine, Germany

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    Background, aim, and scope: The chemical substance 2,4,7,9-tetramethyl-5-decyne-4,7-diol (TMDD) is a non-ionic surfactant used as an industrial defoaming agent and in various other applications. Its commercial name is Surynol 104Âź and the related ethoxylates are also available as SurfynolÂź 420, 440, 465 and 485 which are characterized by different grades of ethoxylation of TMDD at both hydroxyl functional groups. TMDD and its ethoxylates offer several advantages in waterborne industrial applications in coatings, inks, adhesives as well as in paper industries. TMDD and its ethoxylates can be expected to reach the aquatic environment due its widespread use and its physico-chemical properties. TMDD has previously been detected in several rivers of Germany with concentrations up to 2.5 ”g/L. In the United States, TMDD was also detected in drinking water. However, detailed studies about its presence and distribution in the aquatic environment have not been carried out so far. The aim of the present study was the analysis of the spatial and temporal concentration variations of TMDD in the river Rhine at the RheingĂŒtestation Worms (443.3 km). Moreover, the transported load in the Rhine was investigated during two entire days and 7 weeks between November 2007 and January 2008. Materials and methods: The sampling was carried out at three different sampling points across the river. Sampling point MWL1 is located in the left part of the river, MWL2 in the middle part, and MWL4 in the right part. One more sampling site (MWL3) was run by the monitoring station until the end of 2006, but was put out of service due to financial constrains. The water at the left side of the river Rhine (MWL1) is influenced by sewage from a big chemical plant in Ludwigshafen and by the sewage water from this city. The water at the right side of the river Rhine (MWL4) is largely composed of the water inflow from river Neckar, discharging into Rhine 14.9 km upstream from the sampling point and of communal and industrial wastewater from the city Mannheim. The water from the middle of the river (MWL2) is largely composed of water from the upper Rhine. Water samples were collected in 1-L bottles by an automatic sampler. The water samples were concentrated by use of solid-phase extraction (SPE) using Bond Elut PPL cartridges and quantified by use of gas chromatography-mass spectrometry (GC-MS). The quantification was carried out with the internal standard method. Based on these results, concentration variations were determined for the day profiles and week profiles. The total number of analyzed samples was 219. Results: The results of this study provide information on the temporal concentration variability of TMDD in river Rhine in a cross section at one particular sampling point (443.3 km). TMDD was detected in all analyzed water samples at high concentrations. The mean concentrations during the 2 days were 314 ng/L in MWL1, 246 ng/L in MWL2, and 286 ng/L in MWL4. The variation of concentrations was low in the day profiles. In the week profiles, a trend of increasing TMDD concentrations was detected particularly in January 2008, when TMDD concentrations reached values up to 1,330 ng/L in MWL1. The mean TMDD concentrations during the week profiles were 540 ng/L in MWL1, 484 ng/L in MWL2, and 576 ng/L in MWL4. The loads of TMDD were also determined and revealed to be comparable in all three sections of the river. The chemical plant located at the left side of the Rhine is not contributing additional TMDD to the river. The load of TMDD has been determined to be 62.8 kg/d on average during the entire period. By extrapolation of data obtained from seven week profiles the annual load was calculated to 23 t/a. Discussion: The permanent high TMDD concentrations during the investigation period indicate an almost constant discharge of TMDD into the river. This observation argues for effluents of municipal wastewater treatment plants as the most likely source of TMDD in the river. Another possible source might be the degradation of ethoxylates of TMDD (SurfynolÂź series 400), in the WWTPs under formation of TMDD followed by discharge into the river. TMDD has to be considered as a high-production-volume (HPV) chemical based on the high concentrations found in this study. In the United States, TMDD is already in the list of HPV chemicals from the Environmental Protection Agency (EPA). However, the amount of TMDD production in Europe is unknown so far and also the biodegradation rates of TMDD in WWTPs have not been investigated. Conclusions: TMDD was found in high concentrations during the entire sampling period in the Rhine river at the three sampling points. During the sampling period, TMDD concentrations remained constant in each part of the river. These results show that TMDD is uniformly distributed in the water collected at three sampling points located across the river. ‘Waves’ of exceptionally high concentrations of TMDD could not be detected during the sampling period. These results indicate that the effluents of WWTPs have to be considered as the most important sources of TMDD in river Rhine. Recommendations and perspectives: Based also on the occurrence of TMDD in different surface waters of Germany with concentrations up to 2,500 ng/L and its presence in drinking water in the USA, more detailed investigations regarding its sources and distribution in the aquatic environment are required. Moreover, the knowledge with respect to its ecotoxicity and its biodegradation pathway is scarce and has to be gained in more detail. Further research is necessary to investigate the rate of elimination of TMDD in municipal and industrial wastewater treatment plants in order to clarify the degradation rate of TMDD and to determine to which extent effluents of WWTPs contribute to the input of TMDD into surface waters. Supplementary studies are needed to clarify whether the ethoxylates of TMDD (known as Surfynol 400Âź series) are hydrolyzed in the aquatic environment resulting in formation of TMDD similar to the well known cleavage of nonylphenol ethoxylates into nonylphenols. The stability of TMDD under anaerobic conditions in groundwater is also unknown and should be studied

    Influence of operating parameters on the biodegradation of steroid estrogens and nonylphenolic compounds during biological wastewater treatment processes

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    This document is the unedited author's version of a Submitted Work that was subsequently accepted for publication in Environmental Science & Technology, copyright © American Chemical Society after peer review. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/es901612v.This study investigated operational factors influencing the removal of steroid estrogens and nonylphenolic compounds in two sewage treatment works, one a nitrifying/denitrifying activated sludge plant and the other a nitrifying/denitrifying activated sludge plant with phosphorus removal. Removal efficiencies of >90% for steroid estrogens and for longer chain nonylphenol ethoxylates (NP4−12EO) were observed at both works, which had equal sludge ages of 13 days. However, the biological activity in terms of milligrams of estrogen removed per day per tonne of biomass was found to be 50−60% more efficient in the nitrifying/denitrifying activated sludge works compared to the works which additionally incorporated phosphorus removal. A temperature reduction of 6 °C had no impact on the removal of free estrogens, but removal of the conjugated estrone-3-sulfate was reduced by 20%. The apparent biomass sorption (LogKp) values were greater in the nitrifying/denitrifying works than those in the nitrifying/denitrifying works with phosphorus removal for both steroid estrogens and nonylphenolic compounds possibly indicating a different cell surface structure and therefore microbial population. The difference in biological activity (mg tonne−1 d−1) identified in this study, of up to seven times, suggests that there is the potential for enhancing the removal of estrogens and nonylphenols if more detailed knowledge of the factors responsible for these differences can be identified and maximized, thus potentially improving the quality of receiving waters.Public Utilities Board (Singapore), Anglian Water Ltd, Severn Trent Water Ltd, Thames Water Utilities Ltd, United Utilities 393 Plc and Yorkshire Water Services

    Humanization of robots: is it really such a good idea?

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    The aim of this review was to examine the pros and cons of humanizing social robots following a psychological perspective. As such, we had six goals. First, we defined what social robots are. Second, we clarified the meaning of humanizing social robots. Third, we presented the theoretical backgrounds for promoting humanization. Fourth, we conducted a review of empirical results of the positive effects and the negative effects of humanization on human–robot interaction (HRI). Fifth, we presented some of the political and ethical problems raised by the humanization of social robots. Lastly, we discussed the overall effects of the humanization of robots in HRI and suggested new avenues of research and development.info:eu-repo/semantics/publishedVersio

    Smart homes and their users:a systematic analysis and key challenges

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    Published research on smart homes and their users is growing exponentially, yet a clear understanding of who these users are and how they might use smart home technologies is missing from a field being overwhelmingly pushed by technology developers. Through a systematic analysis of peer-reviewed literature on smart homes and their users, this paper takes stock of the dominant research themes and the linkages and disconnects between them. Key findings within each of nine themes are analysed, grouped into three: (1) views of the smart home-functional, instrumental, socio-technical; (2) users and the use of the smart home-prospective users, interactions and decisions, using technologies in the home; and (3) challenges for realising the smart home-hardware and software, design, domestication. These themes are integrated into an organising framework for future research that identifies the presence or absence of cross-cutting relationships between different understandings of smart homes and their users. The usefulness of the organising framework is illustrated in relation to two major concerns-privacy and control-that have been narrowly interpreted to date, precluding deeper insights and potential solutions. Future research on smart homes and their users can benefit by exploring and developing cross-cutting relationships between the research themes identified

    A critical review of the formation of mono- and dicarboxylated metabolic intermediates of alkylphenol polyethoxylates during wastewater treatment and their environmental significance

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    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 Taylor & Francis.Alkylphenoxyacetic acids, the metabolic biodegradation products of alkylphenol ethoxylates, are commonly found in wastewaters and sewage effluents. These persistent hydrophilic derivatives possess intrinsic estrogenic activity, which can mimic natural hormones. Their concentrations increase through the sewage treatment works as a result of biodegradation and biotransformation, and when discharged can disrupt endocrine function in fish. These acidic metabolites represent the dominant alkylphenolic compounds found in wastewater effluent and their presence is cause for concern as, potentially, through further biotransformation and biodegradation, they can act as sources of nonylphenol, which is toxic and estrogenic. The authors aim to assess the mechanisms of formation as well as elimination of alkylphenoxyacetic acids within conventional sewage treatment works with the emphasis on the activated sludge process. In addition, they evaluate the various factors influencing their degradation and formation in laboratory scale and full-scale systems. The environmental implications of these compounds are considered, as is the need for tertiary treatment processes for their removal

    The preference for water nipples vs. water bowls in dairy goats

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    <p>Abstract</p> <p>Background</p> <p>Previous studies have reported that the design of the water dispensers can influence the water intake in farm animals. Horses and dairy cows seem to prefer to drink from an open surface whereas sheep and pigs apparently prefer water nipples, probably because of the worse water quality in water bowls. The aim of the present study was to examine the preference of dairy goats for water nipples or water bowls.</p> <p>Methods</p> <p>In each of the two experiments (exp. 1, dry goats, exp. 2 lactating goats), 42 dairy goats were allotted into 6 groups of 7 goats. In period 1, the goats had access to a water nipple. In period 2, they had access to a water bowl and in period 3 (preference test) they had access to both a water nipple and a water bowl. Water usage and wastage was recorded and water intake (water usage - water wastage) was calculated for each group for the two last days of each period. In experiment 2, water samples from each dispenser were analyzed for heterotrophy germs at 22°C, <it>Escherichia coli </it>and turbidity.</p> <p>Results</p> <p>Water usage was higher from water nipples than from water bowls both in experiment 1 (dry goats) and experiment 2 (lactating goats). There was however, no difference in water intake from water nipples and water bowls. In the preference test (period 3), the water intake tended to be higher from the water nipple than from the water bowl both for the dry goats (exp. 1) and lactating goats (exp. 2). Especially for the dry goats, the differences between groups were large. Turbidity and heterotrophy germs were much higher in the samples from the water bowls than from the water nipples.</p> <p>Water wastage from the water bowls was negligible compared to the water nipples. From the water nipples the water wastage was 30% and 23% of water usage for the dry and lactating goats respectively.</p> <p>Conclusions</p> <p>We conclude that type of water dispenser (nipple or bowl) was probably of minor importance for water intake in goats, but water bowls had a lower water quality.</p

    Initial Sequence and Comparative Analysis of the Cat Genome

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    The genome sequence (1.9-fold coverage) of an inbred Abyssinian domestic cat was assembled, mapped, and annotated with a comparative approach that involved cross-reference to annotated genome assemblies of six mammals (human, chimpanzee, mouse, rat, dog, and cow). The results resolved chromosomal positions for 663,480 contigs, 20,285 putative feline gene orthologs, and 133,499 conserved sequence blocks (CSBs). Additional annotated features include repetitive elements, endogenous retroviral sequences, nuclear mitochondrial (numt) sequences, micro-RNAs, and evolutionary breakpoints that suggest historic balancing of translocation and inversion incidences in distinct mammalian lineages. Large numbers of single nucleotide polymorphisms (SNPs), deletion insertion polymorphisms (DIPs), and short tandem repeats (STRs), suitable for linkage or association studies were characterized in the context of long stretches of chromosome homozygosity. In spite of the light coverage capturing ∌65% of euchromatin sequence from the cat genome, these comparative insights shed new light on the tempo and mode of gene/genome evolution in mammals, promise several research applications for the cat, and also illustrate that a comparative approach using more deeply covered mammals provides an informative, preliminary annotation of a light (1.9-fold) coverage mammal genome sequence

    Exploring the development of a cultural care framework for European caring science

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    The aim of this paper is to discuss the development of a cultural care framework that seeks to inform and embrace the philosophical ideals of caring science. Following a review of the literature that identified a lack of evidence of an explicit relationship between caring science and cultural care, a number of well-established transcultural care frameworks were reviewed. Our purpose was to select one that would resonate with underpinning philosophical values of caring science and that drew on criteria generated by the European Academy of Caring Science members. A modified framework based on the work of Giger and Davidhizar was developed as it embraced many of the values such as humanism that are core to caring science practice. The proposed caring science framework integrates determinants of cultural lifeworld-led care and seeks to provide clear directions for humanizing the care of individuals. The framework is offered to open up debate and act as a platform for further academic enquiry

    Identification of nursing assessment models/tools validated in clinical practice for use with diverse ethno-cultural groups: an integrative review of the literature

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    <p>Abstract</p> <p>Background</p> <p>High income nations are currently exhibiting increasing ethno-cultural diversity which may present challenges for nursing practice. We performed an integrative review of literature published in North America and Europe between 1990 and 2007, to map the state of knowledge and to identify nursing assessment tools/models which are have an associated research or empirical perspective in relation to ethno-cultural dimensions of nursing care.</p> <p>Methods</p> <p>Data was retrieved from a wide variety of sources, including key electronic bibliographic databases covering research in biomedical fields, nursing and allied health, and culture, e.g. CINAHL, MEDline, PUBmed, Cochrane library, PsycINFO, Web of Science, and HAPI. We used the Critical Appraisal Skills Programme tools for quality assessment. We applied Torraco's definition and method of an integrative review that aims to create new knowledge and perspectives on a given phenomena. To add methodological rigor with respect to the search strategy and other key review components we also used the principles established by the Centre for Reviews and Dissemination.</p> <p>Results</p> <p>Thirteen thousand and thirteen articles were retrieved, from which 53 full papers were assessed for inclusion. Eight papers met the inclusion criteria, describing research on a total of eight ethno-cultural assessment tools/models. The tools/models are described and synthesized.</p> <p>Conclusions</p> <p>While many ethno-cultural assessment tools exist to guide nursing practice, few are informed by research perspectives. An increased focus on the efficiency and effectiveness of health services, patient safety, and risk management, means that provision of culturally responsive and competent health services will inevitably become paramount.</p

    Barriers and facilitators to implementing community outreach work, and inter-professional collaboration with regional partners

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    Abstract : Objective. Community outreach workers support individuals in accessing the health and community services they require through various forms of proximity approaches. Even though community outreach has been available in the province of Quebec (Canada) for the past 40 years, it is still difficult to implement and sustain, especially with families of young children. The aim of this study was to document barriers and facilitators to implementing community outreach practices, and to describe how such workers collaborate with sectoral (e.g. health care) and inter-sectoral (e.g. municipalities, community organizations, schools) partners. Methodology. We performed a content analysis on 55 scientific and grey literature documents, and transcriptions of 24 individual interviews and 3 focus groups with stakeholders including parents, community outreach workers, health care employees, and inter-sectoral partners. Results. This study reveals four categories of barriers and facilitators to the implementation of community outreach work (i.e. organizational factors, nature of the work and worker-related factors, family-related factors, external factors). With regards to collaboration, community outreach workers deal with various partners. Good inter-professional collaboration is achieved through positive interactions and communication, shared or co-developed activities for the families, co-intervention with families, and strategies to enhance role awareness and inter-sectoral meetings. Conclusion. Results highlighted that many factors interact and can either influence, positively or negatively, the opportunity to implement community outreach work. The collaborative practices identified may help to maximize facilitators and overcome barriers. Advocacy and a better understanding of how to integrate community outreach work within health services while maintaining the workers’ flexibility are needed to sustain this practice
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