2,275 research outputs found

    Full-scale trials of external nitrification on plastic media nitrifying trickling filter

    Get PDF
    The full-scale single-stage tertiary nitrifying trickling filter (NTF) at the Citrusdal Wastewater Treatment Plant provides for external nitrification of unclarified effluent from the facultative aerobic lagoon in order to meet standard effluent ammonia concentration requirements. The apparent ammonia nitrification rate (ApANR, gN/m2 media surface·d) of the NTF was sensitive to particulate organic loading rates which were predominantly in the form of algae, and the soluble COD removal rates increased under cold climates. Installation of forced-air ventilation fans improved the nitrification efficiency from 15% to 43%. An increase in hydraulic loading rate (HLR) by effluent recirculation significantly improved the ApANR, eradicated filter flies and decreased the prevalence of worms. Maximum ApANR of ~1.0 gN/m2·d was achieved yielding an ammonia- removal efficiency of approximately 71%. Profile samples collected along the NTF media depth indicated poor media wetting at low HLR resulting in low ApANR (<0.5 gN/m2·d). Also during the cold and rainy winter period, poor biofilm activity and prevalence of motile algae were observed, and under low hydraulic loading rates and warmer temperatures, a dominance of filter flies and fly larvae were observed. In contrast, in controlled laboratory studies, ApANRs up to 1.72 gN/m2·d (22.1 mgN/l removal) were attained, which, in conformity with full-scale, was also found to be sensitive to hydraulic loading conditions

    Reforms, entry and productivity: Some evidence from the Indian manufacturing sector

    Get PDF
    It is now stylized that, while the impact of ownership on firm productivity is unclear, product market competition can be expected to have a positive impact on productivity, thereby making entry (or contestability of markets) desirable. Traditional research in the context of entry has explored the strategic reactions of incumbent firms when threatened by the possibility of entry. However, following De Soto (1989), there has been increasing emphasis on regulatory and institutional factors governing entry rates, especially in the context of developing countries. Using 3-digit industry level data from India, for the 1984-97 period, we examine the phenomenon of entry in the Indian context. Our empirical results suggest that during the 1980s industry level factors largely explained variations in entry rates, but that, following the economic federalism brought about by the post-1991 reforms, variations entry rates during the 1990s were explained largely by state level institutional and legacy factors. We also find evidence to suggest that, in India, entry rates were positively associated with growth in total factor productivity

    How to democratize Internet of Things devices. A participatory design research

    Full text link
    The global introduction of affordable Internet of Things (IoT) devices offers an opportunity to empower a large variety of users with different needs. However, many off-the-shelf digital products are still not widely adopted by people who are hesitant technology users or by older adults, notwithstanding that the design and user-interaction of these devices is recognized to be user-friendly. In view of the potential of IoT-based devices, how can we reduce the obstacles of a cohort with low digital literacy and technology anxiety and enable them to be equal participants in the digitalized world? This article shows the method and results achieved in a community-stakeholder workshop, developed through the participatory design methodology, aiming at brainstorming problems and scenarios through a focus group and a structured survey. The research activity focused on understanding factors to increase the usability of off-the-shelf IoT devices for hesitant users and identify strategies for improving digital literacy and reducing technology anxiety. A notable result was a series of feedback items pointing to the importance of creating learning resources to support individuals with different abilities, age, gender expression, to better adopt off-the-shelf IoT-based solutions.Comment: 8 pages, 5 figure

    BRISC—An Open Source Pulmonary Nodule Image Retrieval Framework

    Get PDF
    We have created a content-based image retrieval framework for computed tomography images of pulmonary nodules. When presented with a nodule image, the system retrieves images of similar nodules from a collection prepared by the Lung Image Database Consortium (LIDC). The system (1) extracts images of individual nodules from the LIDC collection based on LIDC expert annotations, (2) stores the extracted data in a flat XML database, (3) calculates a set of quantitative descriptors for each nodule that provide a high-level characterization of its texture, and (4) uses various measures to determine the similarity of two nodules and perform queries on a selected query nodule. Using our framework, we compared three feature extraction methods: Haralick co-occurrence, Gabor filters, and Markov random fields. Gabor and Markov descriptors perform better at retrieving similar nodules than do Haralick co-occurrence techniques, with best retrieval precisions in excess of 88%. Because the software we have developed and the reference images are both open source and publicly available they may be incorporated into both commercial and academic imaging workstations and extended by others in their research

    Functional claudication distance: a reliable and valid measurement to assess functional limitation in patients with intermittent claudication

    Get PDF
    BACKGROUND: Disease severity and functional impairment in patients with intermittent claudication is usually quantified by the measurement of pain-free walking distance (intermittent claudication distance, ICD) and maximal walking distance (absolute claudication distance, ACD). However, the distance at which a patient would prefer to stop because of claudication pain seems a definition that is more correspondent with the actual daily life walking distance. We conducted a study in which the distance a patient prefers to stop was defined as the functional claudication distance (FCD), and estimated the reliability and validity of this measurement. METHODS: In this clinical validity study we included patients with intermittent claudication, following a supervised exercise therapy program. The first study part consisted of two standardised treadmill tests. During each test ICD, FCD and ACD were determined. Primary endpoint was the reliability as represented by the calculated intra-class correlation coefficients. In the second study part patients performed a standardised treadmill test and filled out the Rand-36 questionnaire. Spearman's rho was calculated to assess validity. RESULTS: The intra-class correlation coefficients of ICD, FCD and ACD were 0.940, 0.959, and 0.975 respectively. FCD correlated significantly with five out of nine domains, namely physical function (rho = 0.571), physical role (rho = 0.532), vitality (rho = 0.416), pain (rho = 0.416) and health change (rho = 0.414). CONCLUSION: FCD is a reliable and valid measurement for determining functional capacity in trained patients with intermittent claudication. Furthermore it seems that FCD better reflects the actual functional impairment. In future studies, FCD could be used alongside ICD and ACD

    Considering the Case for Biodiversity Cycles: Reexamining the Evidence for Periodicity in the Fossil Record

    Get PDF
    Medvedev and Melott (2007) have suggested that periodicity in fossil biodiversity may be induced by cosmic rays which vary as the Solar System oscillates normal to the galactic disk. We re-examine the evidence for a 62 million year (Myr) periodicity in biodiversity throughout the Phanerozoic history of animal life reported by Rohde & Mueller (2005), as well as related questions of periodicity in origination and extinction. We find that the signal is robust against variations in methods of analysis, and is based on fluctuations in the Paleozoic and a substantial part of the Mesozoic. Examination of origination and extinction is somewhat ambiguous, with results depending upon procedure. Origination and extinction intensity as defined by RM may be affected by an artifact at 27 Myr in the duration of stratigraphic intervals. Nevertheless, when a procedure free of this artifact is implemented, the 27 Myr periodicity appears in origination, suggesting that the artifact may ultimately be based on a signal in the data. A 62 Myr feature appears in extinction, when this same procedure is used. We conclude that evidence for a periodicity at 62 Myr is robust, and evidence for periodicity at approximately 27 Myr is also present, albeit more ambiguous.Comment: Minor modifications to reflect final published versio

    Metabolic effects of diets differing in glycaemic index depend on age and endogenous GIP

    Get PDF
    Aims/hypothesis High- vs low-glycaemic index (GI) diets unfavourably affect body fat mass and metabolic markers in rodents. Different effects of these diets could be age-dependent, as well as mediated, in part, by carbohydrate-induced stimulation of glucose-dependent insulinotrophic polypeptide (GIP) signalling. Methods Young-adult (16 weeks) and aged (44 weeks) male wild-type (C57BL/6J) and GIP-receptor knockout (Gipr −/− ) mice were exposed to otherwise identical high-carbohydrate diets differing only in GI (20–26 weeks of intervention, n = 8–10 per group). Diet-induced changes in body fat distribution, liver fat, locomotor activity, markers of insulin sensitivity and substrate oxidation were investigated, as well as changes in the gene expression of anorexigenic and orexigenic hypothalamic factors related to food intake. Results Body weight significantly increased in young-adult high- vs low-GI fed mice (two-way ANOVA, p < 0.001), regardless of the Gipr genotype. The high-GI diet in young-adult mice also led to significantly increased fat mass and changes in metabolic markers that indicate reduced insulin sensitivity. Even though body fat mass also slightly increased in high- vs low-GI fed aged wild-type mice (p < 0.05), there were no significant changes in body weight and estimated insulin sensitivity in these animals. However, aged Gipr −/− vs wild-type mice on high-GI diet showed significantly lower cumulative net energy intake, increased locomotor activity and improved markers of insulin sensitivity. Conclusions/interpretation The metabolic benefits of a low-GI diet appear to be more pronounced in younger animals, regardless of the Gipr genotype. Inactivation of GIP signalling in aged animals on a high-GI diet, however, could be beneficial

    Subcoronary versus supracoronary aortic stenosis. an experimental evaluation

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Valvular aortic stenosis is the most common cause of left ventricular hypertrophy due to gradually increasing pressure work. As the stenosis develop the left ventricular hypertrophy may lead to congestive heart failure, increased risk of perioperative complications and also increased risk of sudden death. A functional porcine model imitating the pathophysiological nature of valvular aortic stenosis is very much sought after in order to study the geometrical and pathophysiological changes of the left ventricle, timing of surgery and also pharmacological therapy in this patient group.</p> <p>Earlier we developed a porcine model for aortic stenosis based on supracoronary aortic banding, this model may not completely imitate the pathophysiological changes that occurs when valvular aortic stenosis is present including the coronary blood flow. It would therefore be desirable to optimize this model according to the localization of the stenosis.</p> <p>Methods</p> <p>In 20 kg pigs subcoronary (n = 8), supracoronary aortic banding (n = 8) or sham operation (n = 4) was preformed via a left lateral thoracotomy. The primary endpoint was left ventricular wall thickness; secondary endpoints were heart/body weight ratio and the systolic/diastolic blood flow ratio in the left anterior descending coronary. Statistical evaluation by oneway anova and unpaired t-test.</p> <p>Results</p> <p>Sub- and supracoronary banding induce an equal degree of left ventricular hypertrophy compared with the control group. The coronary blood flow ratio was slightly but not significantly higher in the supracoronary group (ratio = 0.45) compared with the two other groups (subcoronary ratio = 0.36, control ratio = 0.34).</p> <p>Conclusions</p> <p>A human pathophysiologically compatible porcine model for valvular aortic stenosis was developed by performing subcoronary aortic banding. Sub- and supracoronary aortic banding induce an equal degree of left ventricular hypertrophy. This model may be valid for experimental investigations of aortic valve stenosis but studies of left ventricular hypertrophy can be studied equally well by graduated constriction of the ascending aorta.</p

    Cyclin A1 promoter hypermethylation in human papillomavirus-associated cervical cancer

    Get PDF
    BACKGROUND: The aim of this study was to evaluate epigenetic status of cyclin A1 in human papillomavirus-associated cervical cancer. Y. Tokumaru et al., Cancer Res 64, 5982-7 (Sep 1, 2004)demonstrated in head and neck squamous-cell cancer an inverse correlation between cyclin A1 promoter hypermethylation and TP53 mutation. Human papillomavirus-associated cervical cancer, however, is deprived of TP53 function by a different mechanism. Therefore, it was of interest to investigate the epigenetic alterations during multistep cervical cancer development. METHODS: In this study, we performed duplex methylation-specific PCR and reverse transcriptase PCR on several cervical cancer cell lines and microdissected cervical cancers. Furthermore, the incidence of cyclin A1 methylation was studied in 43 samples of white blood cells, 25 normal cervices, and 24, 5 and 30 human papillomavirus-associated premalignant, microinvasive and invasive cervical lesions, respectively. RESULTS: We demonstrated cyclin A1 methylation to be commonly found in cervical cancer, both in vitro and in vivo, with its physiological role being to decrease gene expression. More important, this study demonstrated that not only is cyclin A1 promoter hypermethylation strikingly common in cervical cancer, but is also specific to the invasive phenotype in comparison with other histopathological stages during multistep carcinogenesis. None of the normal cells and low-grade squamous intraepithelial lesions exhibited methylation. In contrast, 36.6%, 60% and 93.3% of high-grade squamous intraepithelial lesions, microinvasive and invasive cancers, respectively, showed methylation. CONCLUSION: This methylation study indicated that cyclin A1 is a potential tumor marker for early diagnosis of invasive cervical cancer

    New International Guidelines and Consensus on the Use of Lung Ultrasound

    Get PDF
    Following the innovations and new discoveries of the last 10 years in the field of lung ultrasound (LUS), a multidisciplinary panel of international LUS experts from six countries and from different fields (clinical and technical) reviewed and updated the original international consensus for point-of-care LUS, dated 2012. As a result, a total of 20 statements have been produced. Each statement is complemented by guidelines and future developments proposals. The statements are furthermore classified based on their nature as technical (5), clinical (11), educational (3), and safety (1) statements
    corecore