Performance evaluation of fault detection methods for wastewater treatment processes

Several methods to detect faults have been developed in various fields, mainly in chemical and process engineering. However, minimal practical guidelines exist for their selection and application. This work presents an index that allows for evaluating monitoring and diagnosis performance of fault detection methods, which takes into account several characteristics, such as false alarms, false acceptance, and undesirable switching from correct detection to non-detection during a fault event. The usefulness of the index to process engineering is demonstrated first by application to a simple example. Then, it is used to compare five univariate fault detection methods (Shewhart, EWMA, and residuals of EWMA) applied to the simulated results of the Benchmark Simulation Model No. 1 long-term (BSM1_LT). The BSM1_LT, provided by the IWA Task Group on Benchmarking of Control Strategies, is a simulation platform that allows for creating sensor and actuator faults and process disturbances in a wastewater treatment plant. The results from the method comparison using BSM1_LT show better performance to detect a sensor measurement shift for adaptive methods (residuals of EWMA) and when monitoring the actuator signals in a control loop (e.g., airflow). Overall, the proposed index is able to screen fault detection methods.     

Simultaneous horizontal gene transfer of a gene coding for ribosomal protein l27 and operational genes in Arthrobacter sp

Phylogenetic analysis of bacterial L27 ribosomal proteins showed that, against taxonomy, the L27 protein from the Actinobacteria Arthrobacter sp. clusters with protein sequences from the Bacillus group. The L27 gene clusters in the Arthrobacter sp. genome with six genes responsible for creatinine and sarcosine degradation. Phylogenetic analyses of orthologue proteins encoded by three of these genes also showed a phylogenetic relationship with Bacillus species. Comparisons between the synonymous codon usage of the Arthrobacter sp. genes and those from complete genomes showed that Arthrobacter genes encoding the L27 ribosomal protein and the proteins responsible for the degradation of creatinine and sarcosine have a codon usage that is more similar to that of Bacillus species than that of Arthrobacter. We suggest that the Arthrobacter sp. genes encoding the L27 ribosomal protein and the proteins responsible for the degradation of creatinine and sarcosine were acquired simultaneously through horizontal gene transfer from an unknown Bacillus species.     

LDH and structural analogues of pyruvate (author's transl)]

Pyruvate related compounds have been tested for their active or inhibitory properties on LDH. Special structure features were needed for compounds to be bound to the enzyme active site. Pyruvate and the LDH molecule were bound by the interaction of the carboxyl group or its ester derivative, with the enzyme. Ethyl pyruvate seemed to behave as a substrate of the enzyme whereas acetophenone, ethyl acetoacetate and beta-oxoglutarate did not act as substrates or inhibitors of LDH. Phenyl pyruvate, alpha-oxoglutarate and L-mandelate are not substrates but inhibitors of the LDH. It seems that a structure having a carbonyl group in the alpha-position to the carboxyl is required for the binding of a compound to the LDH molecule. Glyoxylate alpha-oxobutyrate and alpha-oxovalerianate appear to be worse LDH substrates than pyruvate itself. This seems to suggest that the shortening or the extension of the pyruvate aliphatic chain induces a decrease of the affinity of the enzyme towards their substrate homologues.     

Manipulating the Mouse Mbryo: Easier than Ever!

Transgenic Research -     

Climate Change or Land Use Dynamics: Do We Know What Climate Change Indicators Indicate?

Different components of global change can have interacting effects on biodiversity and this may influence our ability to detect the specific consequences of climate change through biodiversity indicators. Here, we analyze whether climate change indicators can be affected by land use dynamics that are not directly determined by climate change. To this aim, we analyzed three community-level indicators of climate change impacts that are based on the optimal thermal environment and average latitude of the distribution of bird species present at local communities. We used multiple regression models to relate the variation in climate change indicators to: i) environmental temperature; and ii) three landscape gradients reflecting important current land use change processes (land abandonment, fire impacts and urbanization), all of them having forest areas at their positive extremes. We found that, with few exceptions, landscape gradients determined the figures of climate change indicators as strongly as temperature. Bird communities in forest habitats had colder-dwelling bird species with more northern distributions than farmland, burnt or urban areas. Our results show that land use changes can reverse, hide or exacerbate our perception of climate change impacts when measured through community-level climate change indicators. We stress the need of an explicit incorporation of the interactions between climate change and land use dynamics to understand what are current climate change indicators indicating and be able to isolate real climate change impacts.     

Characterization of new regulatory elements within the Drosophila bithorax complex

The homeotic Abdominal-B (Abd-B) gene expression depends on a modular cis-regulatory region divided into discrete functional domains (iab) that control the expression of the gene in a particular segment of the fly. These domains contain regulatory elements implicated in both initiation and maintenance of homeotic gene expression and elements that separate the different domains. In this paper we have performed an extensive analysis of the iab-6 regulatory region, which regulates Abd-B expression at abdominal segment A6 (PS11), and we have characterized two new polycomb response elements (PREs) within this domain. We report that PREs at Abd-B cis-regulatory domains present a particular chromatin structure which is nuclease accessible all along Drosophila development and both in active and repressed states. We also show that one of these regions contains a dCTCF and CP190 dependent activity in transgenic enhancer-blocking assays, suggesting that it corresponds to the Fab-6 boundary element of the Drosophila bithorax complex.     

Mediterranean diets and metabolic syndrome status in the PREDIMED randomized trial

Background:

Little evidence exists on the effect of an energy-unrestricted healthy diet on metabolic syndrome. We evaluated the long-term effect of Mediterranean diets ad libitum on the incidence or reversion of metabolic syndrome.

Methods:

We performed a secondary analysis of the PREDIMED trial — a multicentre, randomized trial done between October 2003 and December 2010 that involved men and women (age 55–80 yr) at high risk for cardiovascular disease. Participants were randomly assigned to 1 of 3 dietary interventions: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with nuts or advice on following a low-fat diet (the control group). The interventions did not include increased physical activity or weight loss as a goal. We analyzed available data from 5801 participants. We determined the effect of diet on incidence and reversion of metabolic syndrome using Cox regression analysis to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).

Results:

Over 4.8 years of follow-up, metabolic syndrome developed in 960 (50.0%) of the 1919 participants who did not have the condition at baseline. The risk of developing metabolic syndrome did not differ between participants assigned to the control diet and those assigned to either of the Mediterranean diets (control v. olive oil HR 1.10, 95% CI 0.94–1.30, p = 0.231; control v. nuts HR 1.08, 95% CI 0.92–1.27, p = 0.3). Reversion occurred in 958 (28.2%) of the 3392 participants who had metabolic syndrome at baseline. Compared with the control group, participants on either Mediterranean diet were more likely to undergo reversion (control v. olive oil HR 1.35, 95% CI 1.15–1.58, p < 0.001; control v. nuts HR 1.28, 95% CI 1.08–1.51, p < 0.001). Participants in the group receiving olive oil supplementation showed significant decreases in both central obesity and high fasting glucose (p = 0.02); participants in the group supplemented with nuts showed a significant decrease in central obesity.

Interpretation:

A Mediterranean diet supplemented with either extra virgin olive oil or nuts is not associated with the onset of metabolic syndrome, but such diets are more likely to cause reversion of the condition. An energy-unrestricted Mediterranean diet may be useful in reducing the risks of central obesity and hyperglycemia in people at high risk of cardiovascular disease. Trial registration: ClinicalTrials.gov, no. ISRCTN35739639.Metabolic syndrome is a cluster of 3 or more related cardiometabolic risk factors: central obesity (determined by waist circumference), hypertension, hypertriglyceridemia, low plasma high-density lipoprotein (HDL) cholesterol levels and hyperglycemia. Having the syndrome increases a person’s risk for type 2 diabetes and cardiovascular disease.^1,2 In addition, the condition is associated with increased morbidity and all-cause mortality.^1,3–5 The worldwide prevalence of metabolic syndrome in adults approaches 25%^6–8 and increases with age,⁷ especially among women,^8,9 making it an important public health issue.Several studies have shown that lifestyle modifications,¹⁰ such as increased physical activity,¹¹ adherence to a healthy diet^12,13 or weight loss,^14–16 are associated with reversion of the metabolic syndrome and its components. However, little information exists as to whether changes in the overall dietary pattern without weight loss might also be effective in preventing and managing the condition.The Mediterranean diet is recognized as one of the healthiest dietary patterns. It has shown benefits in patients with cardiovascular disease^17,18 and in the prevention and treatment of related conditions, such as diabetes,^19–21 hypertension^22,23 and metabolic syndrome.²⁴Several cross-sectional^25–29 and prospective^30–32 epidemiologic studies have suggested an inverse association between adherence to the Mediterranean diet and the prevalence or incidence of metabolic syndrome. Evidence from clinical trials has shown that an energy-restricted Mediterranean diet³³ or adopting a Mediterranean diet after weight loss³⁴ has a beneficial effect on metabolic syndrome. However, these studies did not determine whether the effect could be attributed to the weight loss or to the diets themselves.Seminal data from the PREDIMED (PREvención con DIeta MEDiterránea) study suggested that adherence to a Mediterranean diet supplemented with nuts reversed metabolic syndrome more so than advice to follow a low-fat diet.³⁵ However, the report was based on data from only 1224 participants followed for 1 year. We have analyzed the data from the final PREDIMED cohort after a median follow-up of 4.8 years to determine the long-term effects of a Mediterranean diet on metabolic syndrome.     

Connectivity conservation priorities for individual patches evaluated in the present landscape: how durable and effective are they in the long term?

One of the most widespread approaches for setting spatially‐explicit priorities for connectivity conservation consists in evaluating the effects of the individual removal of each habitat patch (one at a time) from the landscape. It however remains unknown the degree to which such priorities are valid and reliable in the longer term, as subsequent habitat losses and other disruptions accumulate in the landscape. We compared the patch prioritizations and estimated connectivity losses resulting from individual patch removals and from a more exhaustive assessment accounting for the potentially synergistic impacts of multiple habitat losses by testing all possible combinations of patch removals. Habitat availability (reachability) metrics and metapopulation capacity were calculated in purposefully simulated landscapes and in habitat distribution data for three bird species (NE Spain). We found that 1) individual patch removals allowed identifying areas of low contribution to connectivity that remained so after subsequent network modifications, 2) the most important patches identified through individual removals often did not coincide with those patches whose removal would actually be most detrimental after multiple habitat losses. However, these differences were smaller for the habitat reachability metrics, as well as for very mobile species that were largely insensitive to habitat spatial arrangement. If many patch losses over time are likely, it might be a more robust and fruitful conservation strategy for managers to pinpoint those patches that, with a low negative impact on connectivity, can be converted to other land uses, instead of trying to elucidate through individual patch removals which subset of protected patches would be the most effective for conserving as much connectivity as possible in the long term. Individual patch removals provide useful but non‐permanent guidelines that may need to be reassessed when substantial landscape modifications occur, which requires dynamic strategies for connectivity conservation in the face of global change.