2,749 research outputs found
Fungicide Resistance Genetics of Apple Scab fungus Venturia inaequalis
Apple scab, caused by the ascomycete fungus Venturia inaequalis, is considered the most devastating disease on domestic apple crops. Apples are the most important cultivated crop in temperate regions and the United States produced about 4.6 million tons of apples in 2010. Traditional methods to control fungal plant diseases like apple scab are based on the use of chemical compounds that may produce serious negative effects, mainly related with environmental pollution and the development of fungicide resistance. Identifying genes and mechanisms of fungicide resistance in V. inaequalis is imperative to developing new and more effective defenses against the spread of resistance
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The impact of severe asthma on patients’ autonomy: a qualitative study
Background
People living with severe asthma may have ongoing debilitating symptoms despite high‐dose treatment. Clinical guidelines for severe asthma recommend concepts such as patient centeredness, shared decision making and self‐management, at the heart of which lies autonomy.
Objective
This study aimed to explore the role of autonomy in patients’ narratives about their experiences of living with and managing severe asthma.
Methods
In‐depth semi‐structured interviews were video‐ and/or audio‐recorded and transcribed. Data were categorized using a hybrid approach to analysis incorporating both inductive and deductive methods, informed by the self‐determination construct of autonomy. Analysis and comparison across and within categories were conducted to develop final themes.
Results
Twenty‐nine face‐to‐face interviews, lasting 1.5‐4 hours, were conducted across Australia. Patients’ autonomy was enacted or challenged in a range of situations, such as interacting with health‐care providers, maintaining employment, managing symptoms, and dealing with threats to self‐identity. Two main themes were discerned from the analysis: (a) the desire to live an “unconstrained” life; and (b) preservation of self‐identity.
Conclusion
Our findings suggest that autonomy is broader than conventional medical concepts such as decision making and information seeking. Future research should consider these findings when developing and implementing patient‐driven self‐management interventions for those living with severe asthma
Gut microbiota markers in obese adolescent and adult patients: Age-dependent differential patterns
Obesity levels, especially in children, have dramatically increased over the last few decades. Recently, several studies highlighted the involvement of gut microbiota in the pathophysiology of obesity. We investigated the composition of gut microbiota in obese adolescents and adults compared to age-matched normal weight (NW) volunteers in order to assemble age- and obesity-related microbiota profiles. The composition of gut microbiota was analyzed by 16S rRNA-based metagenomics. Ecological representations of microbial communities were computed, and univariate, multivariate, and correlation analyses performed on bacterial profiles. The prediction of metagenome functional content from 16S rRNA gene surveys was carried out. Ecological analyses revealed a dissimilarity among the subgroups, and resultant microbiota profiles differed between obese adolescents and adults. Using statistical analyses, we assigned, as microbial markers, Faecalibacterium prausnitzii and Actinomyces to the microbiota of obese adolescents, and Parabacteroides, Rikenellaceae, Bacteroides caccae, Barnesiellaceae, and Oscillospira to the microbiota of NW adolescents. The predicted metabolic profiles resulted different in adolescent groups. Particularly, biosynthesis of primary bile acid and steroid acids, metabolism of fructose, mannose, galactose, butanoate, and pentose phosphate and glycolysis/gluconeogenesis were for the majority associated to obese, while biosynthesis and metabolism of glycan, biosynthesis of secondary bile acid, metabolism of steroid hormone and lipoic acid were associated to NW adolescents. Our study revealed unique features of gut microbiota in terms of ecological patterns, microbial composition and metabolism in obese patients. The assignment of novel obesity bacterial markers may open avenues for the development of patient-tailored treatments dependent on age-related microbiota profiles
Time evolution of the Partridge-Barton Model
The time evolution of the Partridge-Barton model in the presence of the
pleiotropic constraint and deleterious somatic mutations is exactly solved for
arbitrary fecundity in the context of a matricial formalism. Analytical
expressions for the time dependence of the mean survival probabilities are
derived. Using the fact that the asymptotic behavior for large time is
controlled by the largest matrix eigenvalue, we obtain the steady state values
for the mean survival probabilities and the Malthusian growth exponent. The
mean age of the population exhibits a power law decayment. Some Monte
Carlo simulations were also performed and they corroborated our theoretical
results.Comment: 10 pages, Latex, 1 postscript figure, published in Phys. Rev. E 61,
5664 (2000
Aging and Immortality in a Cell Proliferation Model
We investigate a model of cell division in which the length of telomeres
within the cell regulate their proliferative potential. At each cell division
the ends of linear chromosomes change and a cell becomes senescent when one or
more of its telomeres become shorter than a critical length. In addition to
this systematic shortening, exchange of telomere DNA between the two daughter
cells can occur at each cell division. We map this telomere dynamics onto a
biased branching diffusion process with an absorbing boundary condition
whenever any telomere reaches the critical length. As the relative effects of
telomere shortening and cell division are varied, there is a phase transition
between finite lifetime and infinite proliferation of the cell population.
Using simple first-passage ideas, we quantify the nature of this transition.Comment: 6 pages, 1 figure, 2-column revtex4 format; version 2: final
published form; contains various improvements in response to referee comment
Exact Solution of an Evolutionary Model without Ageing
We introduce an age-structured asexual population model containing all the
relevant features of evolutionary ageing theories. Beneficial as well as
deleterious mutations, heredity and arbitrary fecundity are present and managed
by natural selection. An exact solution without ageing is found. We show that
fertility is associated with generalized forms of the Fibonacci sequence, while
mutations and natural selection are merged into an integral equation which is
solved by Fourier series. Average survival probabilities and Malthusian growth
exponents are calculated indicating that the system may exhibit mutational
meltdown. The relevance of the model in the context of fissile reproduction
groups as many protozoa and coelenterates is discussed.Comment: LaTeX file, 15 pages, 2 ps figures, to appear in Phys. Rev.
Relative telomere lengths in tumor and normal mucosa are related to disease progression and chromosome instability profiles in colorectal cancer
Telomeric dysfunction is linked to colorectal cancer (CRC) initiation. However, the relationship of normal tissue and tumor telomere lengths with CRC progression, molecular features and prognosis is unclear. Here, we measured relative telomere length (RTL) by real-time quantitative PCR in 90 adenomas (aRTL), 419 stage I-IV CRCs (cRTL) and adjacent normal mucosa (nRTL). Age-adjusted RTL was analyzed against germline variants in telomere biology genes, chromosome instability (CIN), microsatellite instability (MSI), CpG island methylator phenotype (CIMP), TP53, KRAS, BRAF mutations and clinical outcomes. In 509 adenoma or CRC patients, nRTL decreased with advancing age. Female gender, proximal location and the TERT rs2736100 G allele were independently associated with longer age-adjusted nRTL. Adenomas and carcinomas exhibited telomere shortening in 79% and 67% and lengthening in 7% and 15% of cases. Age-adjusted nRTL and cRTL were independently associated with tumor stage, decreasing from adenoma to stage III and leveling out or increasing from stage III to IV, respectively. Cancer MSI, CIMP, TP53, KRAS and BRAF status were not related to nRTL or cRTL. Near-tetraploid CRCs exhibited significantly longer cRTLs than CIN- and aneuploidy CRCs, while cRTL was significantly shorter in CRCs with larger numbers of chromosome breaks. Age-adjusted nRTL, cRTL or cRTL:nRTL ratios were not associated with disease-free or overall survival in stage II/III CRC. Taken together, our data show that both normal mucosa and tumor RTL are independently associated with CRC progression, and highlight divergent associations of CRC telomere length with tumor CIN profiles
Deepening democracy within Ireland's social partnership
Ireland's social partnership process, now under attack from a number of quarters, has repeatedly been charged with being 'undemocratic' in that it undermines the sovereign position of elected political representatives, with key policy formulation and decision-making taking place in fora outside the institutions of representative democracy. These critiques echo those against new forms of networked governance more globally. A key question therefore is how (and if) democracy may be deepened within social partnership or its potential successor(s). This article addresses this question by employing a post-liberal democratic framework to examine social partnership in practice, and by drawing lessons from another partnership process, Malawi's PRSP. Drawing from Malawi's experience, it is argued that democracy can be deepened within social partnership when governance deliberations and negotiations are conducted under conditions of vibrant public debate and genuine perspective-based representation, and when the communicative and discursive norms are widened to allow for such representation
The Heumann-Hotzel model for aging revisited
Since its proposition in 1995, the Heumann-Hotzel model has remained as an
obscure model of biological aging. The main arguments used against it were its
apparent inability to describe populations with many age intervals and its
failure to prevent a population extinction when only deleterious mutations are
present. We find that with a simple and minor change in the model these
difficulties can be surmounted. Our numerical simulations show a plethora of
interesting features: the catastrophic senescence, the Gompertz law and that
postponing the reproduction increases the survival probability, as has already
been experimentally confirmed for the Drosophila fly.Comment: 11 pages, 5 figures, to be published in Phys. Rev.
Effect of smoking status on the efficacy of the SMART regimen in high risk asthma
Background and objective: The optimal management of people with asthma with a significant smoking history is uncertain. The aim of this study was to determine whether the efficacy/safety profile of single combination inhaled corticosteroid (ICS)/long acting beta-agonist (LABA) inhaler maintenance and reliever therapy is influenced by smoking status.
Methods: We undertook secondary analyses from an open-label 24-week randomized study of 303 high risk adult asthma patients randomized to budesonide/formoterol 200/6-µg-metred dose inhaler for maintenance (two actuations twice daily) and either budesonide/formoterol 200/6-µg-metred dose inhaler one actuation (‘single ICS/LABA maintenance and reliever therapy (SMART)’ regimen) or salbutamol 100 µg 1–2 actuations for symptom relief (‘Standard’ regimen). Smoking status was classified in to three groups, as ‘current’, ‘ex’ or ‘never’, and a smoking/treatment interaction term tested for each outcome variable. The primary outcome variable was number of participants with at least one severe exacerbation.
Results: There were 59 current, 97 ex and 147 never smokers included in the analyses. The smoking status/treatment interaction term was not statistically significant for any of the outcome measures. With adjustment for smoking status, the number of participants with severe exacerbations was lower with the SMART regimen (OR 0.45, 95% CI: 0.26–0.77, P = 0.004; P value for interaction between smoking status and treatment 0.29).
Conclusion: We conclude that the favourable safety/efficacy profile of the SMART regimen applies to patients with high risk asthma, irrespective of smoking status
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