448 research outputs found
Spin and Statistics and First Principles
It was shown in the early Seventies that, in Local Quantum Theory (that is
the most general formulation of Quantum Field Theory, if we leave out only the
unknown scenario of Quantum Gravity) the notion of Statistics can be grounded
solely on the local observable quantities (without assuming neither the
commutation relations nor even the existence of unobservable charged field
operators); one finds that only the well known (para)statistics of Bose/Fermi
type are allowed by the key principle of local commutativity of observables. In
this frame it was possible to formulate and prove the Spin and Statistics
Theorem purely on the basis of First Principles.
In a subsequent stage it has been possible to prove the existence of a
unique, canonical algebra of local field operators obeying ordinary Bose/Fermi
commutation relations at spacelike separations. In this general guise the Spin
- Statistics Theorem applies to Theories (on the four dimensional Minkowski
space) where only massive particles with finite mass degeneracy can occur. Here
we describe the underlying simple basic ideas, and briefly mention the
subsequent generalisations; eventually we comment on the possible validity of
the Spin - Statistics Theorem in presence of massless particles, or of
violations of locality as expected in Quantum Gravity.Comment: Survey based on a talk given at the Meeting on "Theoretical and
experimental aspects of the spin - statistics connection and related
symmetries", Trieste, Italy - October 21-25, 200
HDBStat!: A platform-independent software suite for statistical analysis of high dimensional biology data
BACKGROUND: Many efforts in microarray data analysis are focused on providing tools and methods for the qualitative analysis of microarray data. HDBStat! (High-Dimensional Biology-Statistics) is a software package designed for analysis of high dimensional biology data such as microarray data. It was initially developed for the analysis of microarray gene expression data, but it can also be used for some applications in proteomics and other aspects of genomics. HDBStat! provides statisticians and biologists a flexible and easy-to-use interface to analyze complex microarray data using a variety of methods for data preprocessing, quality control analysis and hypothesis testing. RESULTS: Results generated from data preprocessing methods, quality control analysis and hypothesis testing methods are output in the form of Excel CSV tables, graphs and an Html report summarizing data analysis. CONCLUSION: HDBStat! is a platform-independent software that is freely available to academic institutions and non-profit organizations. It can be downloaded from our website
The Rewiring of Ubiquitination Targets in a Pathogenic Yeast Promotes Metabolic Flexibility, Host Colonization and Virulence
Funding: This work was funded by the European Research Council [http://erc.europa.eu/], AJPB (STRIFE Advanced Grant; C-2009-AdG-249793). The work was also supported by: the Wellcome Trust [www.wellcome.ac.uk], AJPB (080088, 097377); the UK Biotechnology and Biological Research Council [www.bbsrc.ac.uk], AJPB (BB/F00513X/1, BB/K017365/1); the CNPq-Brazil [http://cnpq.br], GMA (Science without Borders fellowship 202976/2014-9); and the National Centre for the Replacement, Refinement and Reduction of Animals in Research [www.nc3rs.org.uk], DMM (NC/K000306/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Acknowledgments We thank Dr. Elizabeth Johnson (Mycology Reference Laboratory, Bristol) for providing strains, and the Aberdeen Proteomics facility for the biotyping of S. cerevisiae clinical isolates, and to Euroscarf for providing S. cerevisiae strains and plasmids. We are grateful to our Microscopy Facility in the Institute of Medical Sciences for their expert help with the electron microscopy, and to our friends in the Aberdeen Fungal Group for insightful discussions.Peer reviewedPublisher PD
Wheeze in Preschool Age Is Associated with Pulmonary Bacterial Infection and Resolves after Antibiotic Therapy
BACKGROUND: Neonates with airways colonized by Haemophilus influenzae, Streptococcus pneumoniae or Moraxella catarrhalis are at increased risk for recurrent wheeze which may resemble asthma early in life. It is not clear whether chronic colonization by these pathogens is causative for severe persistent wheeze in some preschool children and whether these children might benefit from antibiotic treatment. We assessed the relevance of bacterial colonization and chronic airway infection in preschool children with severe persistent wheezing and evaluated the outcome of long-time antibiotic treatment on the clinical course in such children. METHODOLOGY/PRINCIPAL FINDINGS: Preschool children (n = 42) with severe persistent wheeze but no symptoms of acute pulmonary infection were investigated by bronchoscopy and bronchoalveolar lavage (BAL). Differential cell counts and microbiological and virological analyses were performed on BAL samples. Patients diagnosed with bacterial infection were treated with antibiotics for 2-16 weeks (n = 29). A modified ISAAC questionnaire was used for follow-up assessment of children at least 6 months after bronchoscopy. Of the 42 children with severe wheezing, 34 (81%) showed a neutrophilic inflammation and 20 (59%) of this subgroup had elevated bacterial counts (≥ 10⁴ colony forming units per milliliter) suggesting infection. Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis were the most frequently isolated species. After treatment with appropriate antibiotics 92% of patients showed a marked improvement of symptoms upon follow-up examination. CONCLUSIONS/SIGNIFICANCE: Chronic bacterial infections are relevant in a subgroup of preschool children with persistent wheezing and such children benefit significantly from antibiotic therapy
Spirometric changes in obstructive disease: after all, how much is significant?
OBJECTIVE: To establish the upper limits for changes in FEV1, slow vital capacity (SVC), FVC, and inspiratory capacity (IC) after placebo administration in patients with airflow obstruction. METHODS: One hundred and two adults with airflow obstruction (FEV1 = 62 ± 19% of predicted) were included in the study. All of the participants performed SVC and FVC maneuvers before and after the administration of placebo spray. The changes in FEV1, SVC, FVC, and IC were expressed as absolute values, percentage of change from baseline values, and percentage of predicted values, 95% CIs and 95th percentiles being calculated. Factor analysis was performed in order to determine how those changes clustered. RESULTS: Considering the 95% CIs and 95th percentiles and after rounding the values, we found that the upper limits for a significant response were as follows: FEV1 = 0.20 L, FVC = 0.20 L, SVC = 0.25 L, and IC = 0.30 L (expressed as absolute values); FEV1 = 12%, FVC = 7%, SVC = 10%, and IC = 15% (expressed as percentage of change from baseline values); and FEV1 = 7%, FVC = 6%, SVC = 7%, and IC = 12% (expressed as percentage of predicted values). CONCLUSIONS: In patients with airflow obstruction, IC varies more widely than do FVC and SVC. For IC, values greater than 0.30 L and 15% of change from the baseline value can be considered significant. For FVC, values greater than 0.20 L and 7% of change from the baseline value are significant. Alternatively, changes exceeding 0.20 L and 7% of the predicted value can be considered significant for FEV1 and FVC. On factor analysis, spirometric parameters clustered into three dimensions, expressing changes in flows, volumes, and dynamic hyperinflation.OBJETIVO: Estabelecer os limites superiores para mudanças em VEF1, capacidade vital lenta (CVL), CVF e capacidade inspiratória (CI) após o uso de placebo em pacientes com obstrução ao fluxo aéreo. MÉTODOS: Cento e dois adultos com obstrução ao fluxo aéreo (VEF1 = 62 ± 19% do previsto) foram incluídos neste estudo. Todos os participantes realizaram manobras de CVL e CVF antes e depois do uso de spray de placebo. As mudanças em VEF1, CVL, CVF e CI foram expressas em valores absolutos, porcentagem de variação em relação aos valores basais e porcentagem dos valores previstos, e foram calculados os IC95% e os percentis 95. A análise fatorial foi realizada a fim de determinar como essas alterações se agrupavam. RESULTADOS: Considerando os IC95% e percentis 95 e após o arredondamento dos valores, obtivemos os seguintes limites superiores para resposta significante: VEF1 = 0,20 L, CVF = 0,20 L, CVL = 0,25 L e CI = 0,30 L (em valores absolutos); VEF1 = 12%, CVF = 7%, CVL = 10% e CI = 15% (em porcentagem de variação em relação aos valores basais) e VEF1 = 7%, CVF = 6%, CVL = 7% e CI = 12% (em porcentagem dos valores previstos). CONCLUSÕES: Em pacientes com obstrução ao fluxo aéreo, a CI apresenta maior variabilidade do que a CVF e a CVL. Para a CI, valores maiores que 0,30 L e 15% de variação em relação ao valor basal devem ser considerados significantes. Para CVF, valores maiores que 0,20L e 7% de variação em relação ao valor basal são significantes. Alternativamente, alterações de mais de 0,20 L e 7% do previsto no VEF1 e na CVF devem ser consideradas significantes. Na análise fatorial, os parâmetros espirométricos se agruparam em três dimensões, expressando mudanças no fluxo, volume e hiperinsuflação dinâmica.Universidade Federal do Rio Grande do NorteUniversidade Federal de São Paulo (UNIFESP)Hospital do Servidor Público Estadual de São PauloUNIFESPSciEL
Early blood glucose profile and neurodevelopmental outcome at two years in neonatal hypoxic-ischaemic encephalopathy
Background: To examine the blood glucose profile and the relationship between blood glucose levels and neurodevelopmental outcome in term infants with hypoxic-ischaemic encephalopathy. Methods: Blood glucose values within 72 hours of birth were collected from 52 term infants with hypoxic-ischaemic encephalopathy. Hypoglycaemia [ 150 mg/dL (8.3 mmol/L)] were correlated to neurodevelopmental outcome at 24 months of age. Results: Four fifths of the 468 blood samples were in the normoglycaemic range (392/468:83.8%). Of the remaining 76 samples, 51.3% were in the hypoglycaemic range and (48.7%) were hyperglycaemic. A quarter of the hypoglycaemic samples (28.2%:11/39) and a third of the hyperglycaemic samples (32.4%:12/37) were recorded within the first 30 minutes of life. Mean (SD) blood glucose values did not differ between infants with normal and abnormal outcomes [4.89(2.28) mmol/L and 5.02(2.35) mmol/L, p value = 0.15] respectively. In term infants with hypoxic-ischaemic encephalopathy, early hypoglycaemia (between 0-6 hours of life) was associated with adverse outcome at 24 months of age [OR = 5.8, CI = 1.04-32)]. On multivariate analysis to adjust for grade of HIE this association was not statistically significant. Late hypoglycaemia (6-72 hours of life) was not associated with abnormal outcome [OR = 0.22, CI (0.04-1.14)]. The occurrence of hyperglycaemia was not associated with adverse outcome. Conclusion: During the first 72 hours of life, blood glucose profile in infants with hypoxic-ischaemic encephalopathy varies widely despite a management protocol. Early hypoglycaemia (0-6 hours of life) was associated with severe HIE, and thereby; adverse outcome
NIOX VERO: Individualized Asthma Management in Clinical Practice
As we move toward an era of precision medicine, novel biomarkers of disease will enable the identification and personalized treatment of new endotypes. In asthma, fractional exhaled nitric oxide (FeNO) serves as a surrogate marker of airway inflammation that often correlates with the presence of sputum eosinophils. The increase in FeNO is driven by an upregulation of inducible nitric oxide synthase (iNOS) by cytokines, which are released as a result of type-2 airway inflammation. Scientific evidence supports using FeNO in routine clinical practice. In steroid-naive patients and in patients with mild asthma, FeNO levels decrease within days after corticosteroid treatment in a dose-dependent fashion and increase after steroid withdrawal. In difficult asthma, FeNO testing correlates with anti-inflammatory therapy compliance. Assessing adherence by FeNO testing can remove the confrontational aspect of questioning a patient about compliance and change the conversation to one of goal setting and ways to improve disease management. However, the most important aspect of incorporating FeNO in asthma management is the reduction in the risk of exacerbations. In a recent primary care study, reduction of exacerbation rates and improved symptom control without increasing overall inhaled corticosteroid (ICS) use were demonstrated when a FeNO-guided anti-inflammatory treatment algorithm was assessed and compared to the standard care. A truly personalized asthma management approach—showing reduction of exacerbation rates, overall use of ICS and neonatal hospitalizations—was demonstrated when FeNO testing was applied as part of the treatment algorithm that managed asthma during pregnancy. The aim of this article is to describe how FeNO and the NIOX VERO® analyzer can help to optimize diagnosis and treatment choices and to aid in the monitoring and improvement of clinical asthma outcomes in children and adults
Mechanosensory interactions drive collective behaviour in Drosophila.
Collective behaviour enhances environmental sensing and decision-making in groups of animals. Experimental and theoretical investigations of schooling fish, flocking birds and human crowds have demonstrated that simple interactions between individuals can explain emergent group dynamics. These findings indicate the existence of neural circuits that support distributed behaviours, but the molecular and cellular identities of relevant sensory pathways are unknown. Here we show that Drosophila melanogaster exhibits collective responses to an aversive odour: individual flies weakly avoid the stimulus, but groups show enhanced escape reactions. Using high-resolution behavioural tracking, computational simulations, genetic perturbations, neural silencing and optogenetic activation we demonstrate that this collective odour avoidance arises from cascades of appendage touch interactions between pairs of flies. Inter-fly touch sensing and collective behaviour require the activity of distal leg mechanosensory sensilla neurons and the mechanosensory channel NOMPC. Remarkably, through these inter-fly encounters, wild-type flies can elicit avoidance behaviour in mutant animals that cannot sense the odour--a basic form of communication. Our data highlight the unexpected importance of social context in the sensory responses of a solitary species and open the door to a neural-circuit-level understanding of collective behaviour in animal groups
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