Statistical inference for unreliable grading using the maximum entropy principle.

Quantitatively assessing the level of confidence on a test score can be a challenging problem, especially when the available information is based on multiple criteria. A concrete example beyond the usual grading of tests occurs with recommendation letters, where a recommender assigns a score to a candidate, but the reliability of the recommender must be assessed as well. Here, we present a statistical procedure, based on Bayesian inference and Jaynes' maximum entropy principle, that can be used to estimate the most probable and expected score given the available information in the form of a credible interval. Our results may provide insights on how to properly state and analyze problems related to the uncertain evaluation of performance in learning applied to several contexts, beyond the case study of the recommendation letters presented here.

Recommendations for the prevention and diagnosis of asthma in children: Evidence from international guidelines adapted for Mexico

BACKGROUND: With the availability of high-quality asthma guidelines worldwide, one possible approach of developing a valid guideline, without re-working the evidence, already analysed by major guidelines, is the ADAPTE approach, as was used for the development of National Guidelines on asthma. METHODS: The guidelines development group (GDG) covered a broad range of experts from medical specialities, primary care physicians and methodologists. The core group of the GDG searched the literature for asthma guidelines 2005 onward, and analysed the 11 best guidelines with AGREE-II to select three mother guidelines. Key clinical questions were formulated covering each step of the asthma management. RESULTS: The selected mother guidelines are British Thoracic Society (BTS), GINA and GEMA 2015. Responses to the questions were formulated according to the evidence in the mother guidelines. Recommendations or suggestions were made for asthma treatment in Mexico by the core group, and adjusted during several rounds of a Delphi process, taking into account: 1. Evidence; 2. Safety; 3. Cost; 4. Patient preference - all these set against the background of the local reality. Here the detailed analysis of the evidence present in BTS/GINA/GEMA sections on prevention and diagnosis in paediatric asthma are presented for three age-groups: children with asthma ≤5 years, 6-11 years and ≥12 years. CONCLUSIONS: For the prevention and diagnosis sections, applying the AGREE-II method is useful to develop a scientifically-sustained document, adjusted to the local reality per country, as is the Mexican Guideline on Asthma

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Manifesto on small airway involvement and management in asthma and chronic obstructive pulmonary disease: an Interasma (Global Asthma Association - GAA) and World Allergy Organization (WAO) document endorsed by Allergic Rhinitis and its Impact on Asthma (ARIA) and Global Allergy and Asthma European Network (GA2LEN).

Evidence that enables us to identify, assess, and access the small airways in asthma and chronic obstructive pulmonary disease (COPD) has led INTERASMA (Global Asthma Association) and WAO to take a position on the role of the small airways in these diseases. Starting from an extensive literature review, both organizations developed, discussed, and approved the manifesto, which was subsequently approved and endorsed by the chairs of ARIA and GA2LEN. The manifesto describes the evidence gathered to date and defines and proposes issues on small airway involvement and management in asthma and COPD with the aim of challenging assumptions, fostering commitment, and bringing about change. The small airways (defined as those with an internal diameter <2 mm) are involved in the pathogenesis of asthma and COPD and are the major determinant of airflow obstruction in these diseases. Various tests are available for the assessment of the small airways, and their results must be integrated to confirm a diagnosis of small airway dysfunction. In asthma and COPD, the small airways play a key role in attempts to achieve disease control and better outcomes. Small-particle inhaled formulations (defined as those that, owing to their size [usually <2 µm], ensure more extensive deposition in the lung periphery than large molecules) have proved beneficial in patients with asthma and COPD, especially those in whom small airway involvement is predominant. Functional and biological tools capable of accurately assessing the lung periphery and more intensive use of currently available tools are necessary. In patients with suspected COPD or asthma, small airway involvement must be assessed using currently available tools. In patients with subotpimal disease control and/or functional or biological signs of disease activity, the role of small airway involvement should be assessed and treatment tailored. Therefore, the choice between large- and small-particle inhaled formulations must reflect the physician's considerations of disease features, phenotype, and response to previous therapy. This article is being co-published in Asthma Research and Practice and the World Allergy Organization Journal.

First Report of Root Rot of Chicory Caused by Phytophthora cryptogea in Chile.

Chicory (Cichorium intybus L. var sativum Bisch.), a relatively new high-value crop in Chile, was introduced for commercial production of inulin. Inulins are polysaccharides extracted from chicory tap roots that are used in processed foods because of their beneficial gastrointestinal properties. Approximately 3,000 ha of chicory are grown for local processing in the BioBio Region near Chillan in south central Chile. Recently, a severe rot of 1 to 3% of mature roots in the field and after harvest has been observed in most fields, which caused yield and quality losses. Typical symptoms include a brown discoloration and a soft, watery decay of the root. Tissue pieces from symptomatic roots were placed on water agar and clarified V8 juice agar medium amended with antibiotics (1) for isolation of the causal pathogen. A Phytopthora sp. had been consistently isolated from root lesions, and axenic cultures were obtained using single-hypha transfers. The species was provisionally identified as Phytopthora cryptogea (Pethybridge and Lafferty, 1919) on the basis of morphological and cultural characteristics (1). Mycelia grew between 5 and 30°C with optimal growth at 20 to 25°C and no growth at 35°C. All isolates produced hyphal swellings and nonpapillate, persistent, internally proliferating, and ovoid to obpyriform sporangia with mean dimensions of 45 × 31 µm in sterile soil extract. The isolates were of A1 mating type because they produced oospores only when paired with reference isolates of P. cinnamomi A2 on clarified V8 juice agar amended with thiamine, tryptophan, and ß-sitosterol (1) after 20 days at 20°C in the dark. On the basis of morphological and sequence data from cytochrome c oxidase subunit 1 and 2, internal transcribed spacer 2, and ß-tubulin (GenBank Accession Nos. JQ037796 to JQ037798, respectively), the pathogen was identified as P. cryptogea. Pathogenicity tests were conducted using three isolates of P. cryptogea by placing a 7-mm-diameter disk from a 1-week-old V8 agar culture on 10 wounded and nonwounded healthy chicory roots (2). Control roots were mock inoculated with agar plugs. The inoculated roots were incubated at 20°C in a moist chamber. Root rot symptoms, identical to those observed both in field and storage, developed after 4 to 6 days only on wounded sites inoculated with the pathogen, and P. cryptogea was reisolated from these inoculated plants. Mock-inoculated roots remained healthy. This experiment was completed twice and similar results were obtained. To our knowledge, this is the first report of Phytophthora root rot of chicory caused by P. cryptogea in Chile. References: (1) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (2) M. E. Stanghellini and W. C. Kronland. Plant Dis. 66:262, 1982.

The product of the cysK gene of Bacillus stearothermophilus V mediates potassium tellurite resistance in Escherichia coli.

The nucleotide sequence of a 4,539 bp fragment of Bacillus stearothermophilus V mediating tellurite resistance in Escherichia coli was determined. Four ORFs of more than 150 amino acids encoding polypeptides of 244, 258, 308, and 421 residues were found in the restriction fragment. E. coli cells harboring a recombinant plasmid containing the Ter determinant express, when challenged with tellurite, a 32 kDa protein with an amino terminal sequence identical to the ten first residues of the 308 ORF. This ORF shows great similarity with the cysteine synthase gene (cysK) of a number of organisms. Recombinant clones carrying the active cysK gene have minimal inhibitory concentrations to K2TeO3 that were tenfold higher than those determined for the host strain or that of clones carrying ORFs 244, 258, and 421. Introduction of the B. stearothermophilus V cysK gene into a cysK strain of Salmonella typhimurium LT2 resulted in complementation of the mutation as well as transfer of tellurite resistance.

The amino acidic substitution of cysteine 167 by serine (C167S) in BstVI restriction endonuclease of Bacillus stearothermophilus V affects its conformation and thermostability.

The restriction endonuclease BstVI from Bacillus stearothermophilus V contains three cysteine residues at positions 134, 167 and 180. Titration of Cys residues with DTNB showed that none of them are involved in disulphide bond formation. Cysteine triplets 134 and 167 were modified by recombinant PCR to introduce a serine residue in each case. The mutated genes were cloned into pGEM-T vector and transformed into E. coli JM109. Even though pGEM-T is not designed for expression, the mutant proteins were efficiently expressed in E. coli. The endonuclease carrying the mutation C134S was purified to homogeneity but appeared to be very unstable. In contrast, the C167S mutant enzyme was stable when pure and was studied biochemically. This mutant enzyme was as stable and resistant to protein-denaturing agents as the wild type enzyme. The activity of both enzymes was not affected by preincubations of 2 h at 80 degrees C. A short preincubation at 95 degrees C caused a complete inactivation of the mutant enzyme while the wild type endonuclease retained 30% of its activity. Moreover, the C167S BstVI was more susceptible to be hydrolyzed by proteinase K and trypsine compared to the wild type endonuclease. These results show that the substitution Cys --> Ser at position 167 affects the configuration and thermostability of BstVI restriction endonuclease.

Cloning of a tellurite resistance determinant from Bacillus stearothermophilus V in Escherichia coli.

A potassium tellurite-resistance determinant was isolated from Bacillus stearothermophilus V and cloned in Escherichia coli. Transformed cells formed black colonies when grown on solid media containing permissive tellurite concentrations. The resistance determinant was contained in a B. stearothermophilus V chromosomal DNA fragment of 7 kb.

Biochemical characterization of tellurite-reducing activities of Bacillus stearothermophilus V.

Bacillus stearothermophilus V is a naturally occurring Gram-positive rod which exhibits resistance to potassium tellurite. Crude extracts of this bacterium catalyse the NADH-dependent, protease-sensitive reduction of K2TeO3 in vitro. Two fractions which showed the ability to reduce potassium tellurite (H1 and H2) were obtained. Fraction H1 behaved as a macroaggregate exhibiting a very high molecular mass that could not be estimated accurately. Upon electrophoresis in polyacrylamide gels in the presence of SDS, however, it was resolved into three distinct bands of 60, 41 and 37.5 kDa. On the other hand, an M(r) of 121 was determined for fraction H2 by means of gel filtration and high-pressure liquid chromatography. In SDS-PAGE a unique protein band of 60 kDa was observed, suggesting that it is actually a dimer. Both fractions showed pH and temperature optima of 7.5 and 57 degrees C, respectively. Concentrations of 2.5 M NaCl or 0.35 mM SDS inhibited fraction H2 almost completely, while fraction H1 retained 20% of its activity under the same conditions. Concentrations of 5 mM EDTA caused the activity of both fractions to increase 2-fold. In addition to reducing tellurite, they were also able to reduce Na2SeO3 and Na2SO3 in vitro.