1,721,202 research outputs found
Respirometry for the assessment of biomass activity in Membrane Bioreactors
No full textThe aim of the study was to use respirometric techniques for the characterization of biomass
biokinetic behaviour in several MBR pilot plants characterized by different configurations,
different operational conditions and fed with wastewater of different features
(domestic/industrial). Four different MBR pilot plants were investigated: i) a sequencing batch
MBR (SB-MBR) subjected to a gradual salinity increase; ii) a pre-denitrification MBR system
for the treatment of saline wastewater contaminated by hydrocarbons; iii) a University of Cape
Town MBR system (UCT-MBR) for the treatment of domestic wastewater subjected to a
carbon-to-nitrogen (C/N) ratio variation; iiii) a UCT-IFAS-MBR for the treatment of domestic
wastewater characterized by the variation of several operational parameters. The achieved
results highlighted the significant influence that plant configuration and operational conditions
might exert on biomass respiratory activity, referring to both autotrophic and heterotrophic
bacterial species
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Biological stability assessment of MSW organic fractions by means of respirometric and germination tests
Full text linkComposting is the mostly applied method for recovering the organic waste by producing an organic soil conditioner. Furthermore, the organic fraction of unsorted municipal solid waste (OFMSW) should be treated in mechanical biological treatment (MBT) plants in view of reducing its environmental impacts. In both cases, it is essential the assessment of biological stability as well as the phytotoxicity of the final product. The aim of this work was to evaluate the maturity evolution during the composting process of OFMSW at full scale. Samples were collected from two Sicilian (Italy) plants and were subjected to the following analytical measures: volatile solids (VS), dynamic respirometric index (DRI), carbon-to-nitrogen (C/N) ratio and germination index (GI). Results showed that some parameters such as pH and water content values can affect the respirometric test response and the proper activity of microorganisms responsible for biodegradation at full scale. For the unsorted waste, the DRI values suggested that depending on the initial values the stabilization duration might be increased prior to landfilling. DRI revealed to be effective for the assessment of the matrix stability, even if the simultaneous measurements of different indices can provide a reliable information of biological stability and maturity of the organic matrices
Preliminary evaluation of biopolymers production by mixed microbial culture from citrus wastewater in a MBR system using respirometric techniques
Full text linkThis preliminary study was aimed at evaluating the feasibility to produce biopolymers (BP) from citrus wastewater by mixed microbial culture in an anaerobic/aerobic membrane bioreactor (A/O-MBR). The activated sludge of the A/O-MBR was successfully enriched in microorganisms having a good capacity in producing intracellular biopolymers. The production of BP was found to be about 0.55 mgCOD mgCOD−1 using pure acetate at a concentration of 1000 mgCOD L−1. When using fermented wastewater, the conversion of acetate into BP product was 0.56 mgCOD mgCOD−1 in the test performed with C/N equal to 1000:1, whereas it was only 0.12 mgCOD mgCOD−1 in the test with C/N of 100:5. The results achieved suggested the feasibility to use citrus wastewater as a feedstock for biopolymers production although the low biomass storage capacity (0.26 mgCOD mgCODbiomass−1) suggested the need for optimizing the operating conditions in future studies
Treatment of high strength industrial wastewater with membrane bioreactors for water reuse: Effect of pre-treatment with aerobic granular sludge on system performance and fouling tendency
Full text linkIn this study, the treatment of citrus wastewater with membrane bioreactors (MBRs) under different configurations was investigated for water reuse. In particular, one MBR and one aerobic granular sludge MBR (AGS+MBR) bench scale plants were operated for 60 days. The experimental campaign was divided into two periods. In Phase I, a conventional hollow fiber MBR was employed for the treatment of the raw high strength wastewater, whereas in Phase II a combination of in-series reactors (AGS plus MBR) was adopted for the treatment of the high strength citrus wastewater
The results demonstrated that both plant configurations enabled very high COD removal, with average values close to 99%. Respirometric batch tests revealed a considerable high metabolic activity of the biomass in both plant configurations, with higher values in the AGS+MBR. It was speculated that the MBR reactor enriched in active biomass deriving from the erosion of the external granule layers in the upstream reactor. In terms of fouling tendency, higher resistance to filtration was observed in the AGS+MBR plant, also characterized by higher irremovable resistance increase compared to the MBR plant that might severely affect the membrane service life
Circulating Tumor DNA as a Biomarker for Outcomes Prediction in Col-orectal Cancer Patients
No full textCirculating tumour DNA (ctDNA) is a novel tool that has been investigated in several types of tumours, including colorectal cancer (CRC). In fact, the techniques based on liquid biopsies are proposed as appealing non-invasive alternatives to tissue biopsy, adding more insights into tumour molecular profile, heterogeneity and for cancer detection and monitoring. Additionally, some analysis showed that in CRC patients, ctDNA seems to act as a biomarker able to predict the outcome (prognostic role) and the response to treatments (predictive role). In particular, in the early stage CRC (stage I-III), it could represent a time marker of adjuvant therapy as well as a marker of minimal residual disease and recurrence risk in addition to the already recognized risk factors. In metastatic CRC, the analysis of molecular tumour profile by ctDNA has shown to have high concordance with the tissue biopsy at diagnosis. Additionally, some studies demonstrated that ctDNA level during the treatment was linked with the early response to treatment and prognosis. Finally, the quantitative analysis of ctDNA and copy number alterations may be useful in order to detect resistance to therapy at the time of progression of disease and to help in finding new therapeutic targets
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