Validación de un cuestionario para medir retrospectivamente la exposición laboral a plaguicidas

ResumenObjetivosValidar un cuestionario diseñado para medir retrospectivamente la exposición laboral a plaguicidas en un estudio de casos y controles sobre trabajadores expuestos a plaguicidas y malformaciones congénitas.MétodosSe compara la información obtenida mediante una entrevista personal con 56 agricultores con: 1) una entrevista con los empleadores de los agricultores, 2) la observación directa de los lugares de trabajo y 3) un cuestionario que cumplimentaron los agncultores durante la realización del Programa de Capacitación para Manipuladores de Plaguicidas.ResultadosLos índices de exactitud y fiabilidad fueron altos para las variables «cultivos trabajados», «períodos de tratamiento» y «utilización de protección personal», con sensibilidades entre 0,81 y 1 e índices Kappa de 0,65 a 0,80. Sin embargo, las variables «duración de los tratamientos» y «productos plaguicidas utilizados» presentaron índices de exactitud más bajos con sensibilidades entre 0,32 y 0,50.ConclusionesLos resultados sugieren que el cuestionario es un buen instrumento para la medición de algunas variables pero en otras reflejan la existencia de problemas de recuerdo. Esto hace necesario adoptar medidas que mejoren la exactitud de la medida de la exposición como la introducción en el cuestionario del tamaño del área tratada como otra variable que permita valorar la duración de la exposición y la utilización de listas de recuerdo de productos plaguicidas durante la entrevista.SummaryObjectiveThe aim of this study is to validate a questionnaire intended to assess retrospective occupational exposure to pesticides in a case control study of workers exposed to pesticides and congenital malformations.MethodsOccupational data were gathered through personal interviews to 56 agricultural workers and this information was compared to: 1) personal interviews with the workers’ foremen, 2) direct observation of working places and 3) another questionnaire self-administered previously by the workers as a part of the «Training Program for Pesticide Aplicators».ResultsAccuracy and reliability indices are high for variables such as the crops where the interviewees have been working, the time period of the treatments with pesticides and the use of personal protection during treatments (sensitivity ranges between 0.81 and 1 and Kappa index ranges between 0.65 and 0.80). However, for variables such as the duration of the treatments and the pesticides used, sensitivity values range between 0.32 and 0.50.ConclusionsThe results suggest that the questionnaire is a valid tool for measuring some items but in order to improve the quality of the exposure assessment the questionnaire was modified, including a question about size of treated areas (as a proxy variable for duration of treatments) and prompt lists were developed to make easier recall by the workers of specific pesticides used in treatments

A morpholino oligomer therapy regime that restores mitochondrial function and prevents mdx cardiomyopathy

Current clinical trials demonstrate Duchenne muscular dystrophy (DMD) patients receiving phosphorodiamidate morpholino oligomer (PMO) therapy exhibit improved ambulation and stable pulmonary function; however, cardiac abnormalities remain. Utilizing the same PMO chemistry as current clinical trials, we have identified a non-toxic PMO treatment regimen that restores metabolic activity and prevents DMD cardiomyopathy. We propose that a treatment regimen of this nature may have the potential to significantly improve morbidity and mortality from DMD by improving ambulation, stabilizing pulmonary function, and preventing the development of cardiomyopathy

Large superconducting dipole magnet for the heavy ion spectrometer system (HISS)

The magnet is the central element of the spectrometer system, where it will be used to momentum-analyze secondary heavy-ion fragments at relativistic energies. High bending power and large acceptance apertures are necessary for simultaneous multiple fragment measurements. Free access over large angles to the magnetic volume is necessary to accommodate a variety of experiments and particle detection systems. The magnet has pole tips two meters in diameter, a one meter gap, and a maximum central field of three tesla. The coils are designed to be cryostable, with a helical winding pattern. A window-frame steel yoke limits the stray field and augments the cental field. In terms of its magnetic energy of 55 MJ it will be one of the twelve or so largest magnets in the world. Unusual engineering features of the magnet are the large magnetic forces (one million kg) between the coils at liquid helium temperature and the yoke at room temperature, and the large diameter (7 m) hydraulic cylinder base to provide rotation for the magnet. The magnet will be installed at the BEVALAC heavy-ion facility at Lawrence Berkeley Laboratory

Quantum Error Correction via Convex Optimization

We show that the problem of designing a quantum information error correcting procedure can be cast as a bi-convex optimization problem, iterating between encoding and recovery, each being a semidefinite program. For a given encoding operator the problem is convex in the recovery operator. For a given method of recovery, the problem is convex in the encoding scheme. This allows us to derive new codes that are locally optimal. We present examples of such codes that can handle errors which are too strong for codes derived by analogy to classical error correction techniques.Comment: 16 page

Cortical Surface Area Differentiates Familial High Risk Individuals Who Go on to Develop Schizophrenia

BACKGROUND: Schizophrenia is associated with structural brain abnormalities that may be present before disease onset. It remains unclear whether these represent general vulnerability indicators or are associated with the clinical state itself. METHODS: To investigate this, structural brain scans were acquired at two time points (mean scan interval 1.87 years) in a cohort of individuals at high familial risk of schizophrenia (n 5 142) and control subjects (n 5 36). Cortical reconstructions were generated using FreeSurfer. The high-risk cohort was subdivided into individuals that remained well during the study, individuals that had transient psychotic symptoms, and individuals that subsequently became ill. Baseline measures and longitudinal change in global estimates of thickness and surface area and lobar values were compared, focusing on overall differences between high-risk individuals and control subjects and then on group differences within the high-risk cohort. RESULTS: Longitudinally, control subjects showed a significantly greater reduction in cortical surface area compared with the high-risk group. Within the high-risk group, differences in surface area at baseline predicted clinical course, with individuals that subsequently became ill having significantly larger surface area than individuals that remained well during the study. For thickness, longitudinal reductions were most prominent in the frontal, cingulate, and occipital lobes in all high-risk individuals compared with control subjects. CONCLUSIONS: Our results suggest that larger surface areas at baseline may be associated with mechanisms that go above and beyond a general familial disposition. A relative preservation over time of surface area, coupled with a thinning of the cortex compared with control subjects, may serve as vulnerability markers of schizophrenia

Deletion of dystrophin In-Frame Exon 5 leads to a severe phenotype: Guidance for Exon skipping strategies

Duchenne and Becker muscular dystrophy severity depends upon the nature and location of the DMD gene lesion and generally correlates with the dystrophin open reading frame. However, there are striking exceptions where an in-frame genomic deletion leads to severe pathology or protein-truncating mutations (nonsense or frame-shifting indels) manifest as mild disease. Exceptions to the dystrophin reading frame rule are usually resolved after molecular diagnosis on muscle RNA. We report a moderate/severe Becker muscular dystrophy patient with an in-frame genomic deletion of DMD exon 5. This mutation has been reported by others as resulting in Duchenne or Intermediate muscular dystrophy, and the loss of this in-frame exon in one patient led to multiple splicing events, including omission of exon 6, that disrupts the open reading frame and is consistent with a severe phenotype. The patient described has a deletion of dystrophin exon 5 that does not compromise recognition of exon 6, and although the deletion does not disrupt the reading frame, his clinical presentation is more severe than would be expected for classical Becker muscular dystrophy. We suggest that the dystrophin isoform lacking the actin-binding sequence encoded by exon 5 is compromised, reflected by the phenotype resulting from induction of this dystrophin isoform in mouse muscle in vivo. Hence, exon skipping to address DMD-causing mutations within DMD exon 5 may not yield an isoform that confers marked clinical benefit. Additional studies will be required to determine whether multi-exon skipping strategies could yield more functional dystrophin isoforms, since some BMD patients with larger in-frame deletions in this region have been reported with mild phenotypes

Quantized charge transport through a static quantum dot using a surface acoustic wave

We present a detailed study of the surface acoustic wave mediated quantized transport of electrons through a split gate device containing an impurity potential defined quantum dot within the split gate channel. A new regime of quantized transport is observed at low RF powers where the surface acoustic wave amplitude is comparable to the quantum dot charging energy. In this regime resonant transport through the single-electron dot state occurs which we interpret as turnstile-like operation in which the traveling wave amplitude modulates the entrance and exit barriers of the quantum dot in a cyclic fashion at GHz frequencies. For high RF powers, where the amplitude of the surface acoustic wave is much larger than the quantum dot energies, the quantized acoustoelectric current transport shows behavior consistent with previously reported results. However, in this regime, the number of quantized current plateaus observed and the plateau widths are determined by the properties of the quantum dot, demonstrating that the microscopic detail of the potential landscape in the split gate channel has a profound influence on the quantized acoustoelectric current transport.Comment: 9 page

Hartman effect in presence of Aharanov Bohm flux

The Hartman effect for the tunneling particle implies the independence of group delay time on the opaque barrier width, with superluminal velocities as a consequence. This effect is further examined on a quantum ring geometry in the presence of Aharonov-Bohm flux. We show that while tunneling through an opaque barrier the group delay time for given incident energy becomes independent of the barrier thickness as well as the magnitude of the flux. The Hartman effect is thereby extended beyond one dimension and in the presence of Aharonov-Bohm flux.Comment: 4 pages, 4 figure