Hidrogenionic potential (pH) of the attractant, trap density and control threshold for Ceratitis capitata (DIPTERA: TEPHRITIDAE) on Hamlin oranges in São Paulo central region, Brazil

This study evaluated the effect of initial pH values of 4.5, 6.5 and 8.5 of the attractant (protein bait) Milhocina® and borax (sodium borate) in the field, on the capture of fruit flies in McPhail traps, using 1, 2, 4 and 8 traps per hectare, in order to estimate control thresholds in a Hamlin orange grove in the central region of the state of São Paulo. The most abundant fruit fly species was Ceratitis capitata, comprising almost 99% of the fruit flies captured, of which 80% were females. The largest captures of C. capitata were found in traps baited with Milhocina® and borax at pH 8.5. Captures per trap for the four densities were similar, indicating that the population can be estimated with one trap per hectare in areas with high populations. It was found positive relationships between captures of C. capitata and the number of Hamlin oranges damaged, 2 and 3 weeks after capture. It was obtained equations that correlate captures and damage levels which can be used to estimate control thresholds. The average loss caused in Hamlin orange fruits by C. capitata was 2.5 tons per hectare or 7.5% of production.

Comparison of double-locus sequence typing (DLST) and multilocus sequence typing (MLST) for the investigation of Pseudomonas aeruginosa populations.

Reliable molecular typing methods are necessary to investigate the epidemiology of bacterial pathogens. Reference methods such as multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) are costly and time consuming. Here, we compared our newly developed double-locus sequence typing (DLST) method for Pseudomonas aeruginosa to MLST and PFGE on a collection of 281 isolates. DLST was as discriminatory as MLST and was able to recognize "high-risk" epidemic clones. Both methods were highly congruent. Not surprisingly, a higher discriminatory power was observed with PFGE. In conclusion, being a simple method (single-strand sequencing of only 2 loci), DLST is valuable as a first-line typing tool for epidemiological investigations of P. aeruginosa. Coupled to a more discriminant method like PFGE or whole genome sequencing, it might represent an efficient typing strategy to investigate or prevent outbreaks.

The inequality trap. A comparative analysis of social spending between 1880 and 1933

[spa] Utilizando dos indicadores alternativos de redistribución –las transferencias sociales y el gasto social- durante el periodo de tiempo comprendido entre 1880 y 1933, y utilizando dos indicadores alternativos de desigualdad –el porcentaje de explotaciones agrarias no familiares y los top income shares-, este papel muestra que, al contrario de lo que muchos estudios sobre los origines del Estado del Bienestar suelen sugerir, la desigualdad no favoreció el desarrollo de la política social ni siquiera en sus etapas iniciales. Ello significa que la política social se desarrolló más rápidamente en los países que previamente ya eran más igualitarios, lo que sugiere que los países con más desigualdad se encontraban en una especie de trampa de la desigualdad, donde la desigualdad en si misma fue uno de los obstáculos a la redistribución.

Counter-propagating dual-trap optical tweezers based on linear momentum conservation

We present a dual-trap optical tweezers setup which directly measures forces using linear momentum conservation. The setup uses a counter-propagating geometry, which allows momentum measurement on each beam separately. The experimental advantages of this setup include low drift due to all-optical manipulation, and a robust calibration (independent of the features of the trapped object or buffer medium) due to the force measurement method. Although this design does not attain the high-resolution of some co-propagating setups, we show that it can be used to perform different single molecule measurements: fluctuation-based molecular stiffness characterization at different forces and hopping experiments on molecular hairpins. Remarkably, in our setup it is possible to manipulate very short tethers (such as molecular hairpins with short handles) down to the limit where beads are almost in contact. The setup is used to illustrate a novel method for measuring the stiffness of optical traps and tethers on the basis of equilibrium force fluctuations, i.e., without the need of measuring the force vs molecular extension curve. This method is of general interest for dual trap optical tweezers setups and can be extended to setups which do not directly measure forces.

Force Spectroscopy with Dual-Trap Optical Tweezers: Molecular Stiffness Measurements and Coupled Fluctuations Analysis

ABSTRACT Dual-trap optical tweezers are often used in high-resolution measurements in single-molecule biophysics. Such measurements can be hindered by the presence of extraneous noise sources, the most prominent of which is the coupling of fluctuations along different spatial directions, which may affect any optical tweezers setup. In this article, we analyze, both from the theoretical and the experimental points of view, the most common source for these couplings in dual-trap optical-tweezers setups: the misalignment of traps and tether. We give criteria to distinguish different kinds of misalignment, to estimate their quantitative relevance and to include them in the data analysis. The experimental data is obtained in a, to our knowledge, novel dual-trap optical-tweezers setup that directly measures forces. In the case in which misalignment is negligible, we provide a method to measure the stiffness of traps and tether based on variance analysis. This method can be seen as a calibration technique valid beyond the linear trap region. Our analysis is then employed to measure the persistence length of dsDNA tethers of three different lengths spanning two orders of magnitude. The effective persistence length of such tethers is shown to decrease with the contour length, in accordance with previous studies.

The inequality trap. A comparative analysis of social spending between 1880 and 1933

[spa] Utilizando dos indicadores alternativos de redistribución –las transferencias sociales y el gasto social- durante el periodo de tiempo comprendido entre 1880 y 1933, y utilizando dos indicadores alternativos de desigualdad –el porcentaje de explotaciones agrarias no familiares y los top income shares-, este papel muestra que, al contrario de lo que muchos estudios sobre los origines del Estado del Bienestar suelen sugerir, la desigualdad no favoreció el desarrollo de la política social ni siquiera en sus etapas iniciales. Ello significa que la política social se desarrolló más rápidamente en los países que previamente ya eran más igualitarios, lo que sugiere que los países con más desigualdad se encontraban en una especie de trampa de la desigualdad, donde la desigualdad en si misma fue uno de los obstáculos a la redistribución.

Allelic diversity and population structure in Vibrio cholerae O139 Bengal based on nucleotide sequence analysis

Comparative analysis of gene fragments of six housekeeping loci, distributed around the two chromosomes of Vibrio cholerae, has been carried out for a collection of 29 V. cholerae O139 Bengal strains isolated from India during the first epidemic period (1992 to 1993). A toxigenic O1 ElTor strain from the seventh pandemic and an environmental non-O1/non-O139 strain were also included in this study. All loci studied were polymorphic, with a small number of polymorphic sites in the sequenced fragments. The genetic diversity determined for our O139 population is concordant with a previous multilocus enzyme electrophoresis study in which we analyzed the same V. cholerae O139 strains. In both studies we have found a higher genetic diversity than reported previously in other molecular studies. The results of the present work showed that O139 strains clustered in several lineages of the dendrogram generated from the matrix of allelic mismatches between the different genotypes, a finding which does not support the hypothesis previously reported that the O139 serogroup is a unique clone. The statistical analysis performed in the V. cholerae O139 isolates suggested a clonal population structure. Moreover, the application of the Sawyer's test and split decomposition to detect intragenic recombination in the sequenced gene fragments did not indicate the existence of recombination in our O139 population.

Draft genome sequence of Aeromonas molluscorum strain 848TT, isolated from bivalve molluscs

We report here the draft genome sequence of Aeromonas molluscorum 848T, the type strain of this Aeromonas species, which was isolated from wedge shells (Donax trunculus) obtained from a retail market in Barcelona, Spain, in 1997.

Using music as a signal for biofeedback

Studies on the potential benefits of conveying biofeedback stimulus using a musical signal have appeared in recent years with the intent of harnessing the strong effects that music listening may have on subjects. While results are encouraging, the fundamental question has yet to be addressed, of how combined music and biofeedback compares to the already established use of either of these elements separately. This experiment, involving young adults (N = 24), compared the effectiveness at modulating participants' states of physiological arousal of each of the following conditions: A) listening to pre-recorded music, B) sonification biofeedback of the heart rate, and C) an algorithmically modulated musical feedback signal conveying the subject's heart rate. Our hypothesis was that each of the conditions (A), (B) and (C) would differ from the other two in the extent to which it enables participants to increase and decrease their state of physiological arousal, with (C) being more effective than (B), and both more than (A). Several physiological measures and qualitative responses were recorded and analyzed. Results show that using musical biofeedback allowed participants to modulate their state of physiological arousal at least equally well as sonification biofeedback, and much better than just listening to music, as reflected in their heart rate measurements, controlling for respiration-rate. Our findings indicate that the known effects of music in modulating arousal can therefore be beneficially harnessed when designing a biofeedback protocol.

Single cell tuning of Myc expression by antigen receptor signal strength and interleukin-2 in T lymphocytes.

Myc controls the metabolic reprogramming that supports effector T cell differentiation. The expression of Myc is regulated by the T cell antigen receptor (TCR) and pro-inflammatory cytokines such as interleukin-2 (IL-2). We now show that the TCR is a digital switch for Myc mRNA and protein expression that allows the strength of the antigen stimulus to determine the frequency of T cells that express Myc. IL-2 signalling strength also directs Myc expression but in an analogue process that fine-tunes Myc quantity in individual cells via post-transcriptional control of Myc protein. Fine-tuning Myc matters and is possible as Myc protein has a very short half-life in T cells due to its constant phosphorylation by glycogen synthase kinase 3 (GSK3) and subsequent proteasomal degradation. We show that Myc only accumulates in T cells exhibiting high levels of amino acid uptake allowing T cells to match Myc expression to biosynthetic demands. The combination of digital and analogue processes allows tight control of Myc expression at the population and single cell level during immune responses.

Genome sequence of Plesiomonas shigelloides strain 302-73 (serotype O1)

Plesiomonas shigelloides, the only species of the genus, is an emergent pathogenic bacterium associated with human diarrheal and extraintestinal disease. We present the whole-genome sequence analysis of the representative strain for the O1 serotype (strain 302-73), providing a tool for studying bacterial outbreaks, virulence factors, and accurate diagnostic methods.

Cardiovascular magnetic resonance imaging techniques for motion-suppressed multi-dimensional coronary artery imaging with high spatial and temporal resolution

L'imagerie par résonance magnétique (IRM) peut fournir aux cardiologues des informations diagnostiques importantes sur l'état de la maladie de l'artère coronarienne dans les patients. Le défi majeur pour l'IRM cardiaque est de gérer toutes les sources de mouvement qui peuvent affecter la qualité des images en réduisant l'information diagnostique. Cette thèse a donc comme but de développer des nouvelles techniques d'acquisitions des images IRM, en changeant les techniques de compensation du mouvement, pour en augmenter l'efficacité, la flexibilité, la robustesse et pour obtenir plus d'information sur le tissu et plus d'information temporelle. Les techniques proposées favorisent donc l'avancement de l'imagerie des coronaires dans une direction plus maniable et multi-usage qui peut facilement être transférée dans l'environnement clinique. La première partie de la thèse s'est concentrée sur l'étude du mouvement des artères coronariennes sur des patients en utilisant la techniques d'imagerie standard (rayons x), pour mesurer la précision avec laquelle les artères coronariennes retournent dans la même position battement après battement (repositionnement des coronaires). Nous avons découvert qu'il y a des intervalles dans le cycle cardiaque, tôt dans la systole et à moitié de la diastole, où le repositionnement des coronaires est au minimum. En réponse nous avons développé une nouvelle séquence d'acquisition (T2-post) capable d'acquérir les données aussi tôt dans la systole. Cette séquence a été testée sur des volontaires sains et on a pu constater que la qualité de visualisation des artère coronariennes est égale à celle obtenue avec les techniques standard. De plus, le rapport signal sur bruit fourni par la séquence d'acquisition proposée est supérieur à celui obtenu avec les techniques d'imagerie standard. La deuxième partie de la thèse a exploré un paradigme d'acquisition des images cardiaques complètement nouveau pour l'imagerie du coeur entier. La technique proposée dans ce travail acquiert les données sans arrêt (free-running) au lieu d'être synchronisée avec le mouvement cardiaque. De cette façon, l'efficacité de la séquence d'acquisition est augmentée de manière significative et les images produites représentent le coeur entier dans toutes les phases cardiaques (quatre dimensions, 4D). Par ailleurs, l'auto-navigation de la respiration permet d'effectuer cette acquisition en respiration libre. Cette technologie rend possible de visualiser et évaluer l'anatomie du coeur et de ses vaisseaux ainsi que la fonction cardiaque en quatre dimensions et avec une très haute résolution spatiale et temporelle, sans la nécessité d'injecter un moyen de contraste. Le pas essentiel qui a permis le développement de cette technique est l'utilisation d'une trajectoire d'acquisition radiale 3D basée sur l'angle d'or. Avec cette trajectoire, il est possible d'acquérir continûment les données d'espace k, puis de réordonner les données et choisir les paramètres temporel des images 4D a posteriori. L'acquisition 4D a été aussi couplée avec un algorithme de reconstructions itératif (compressed sensing) qui permet d'augmenter la résolution temporelle tout en augmentant la qualité des images. Grâce aux images 4D, il est possible maintenant de visualiser les artères coronariennes entières dans chaque phase du cycle cardiaque et, avec les mêmes données, de visualiser et mesurer la fonction cardiaque. La qualité des artères coronariennes dans les images 4D est la même que dans les images obtenues avec une acquisition 3D standard, acquise en diastole Par ailleurs, les valeurs de fonction cardiaque mesurées au moyen des images 4D concorde avec les valeurs obtenues avec les images 2D standard. Finalement, dans la dernière partie de la thèse une technique d'acquisition a temps d'écho ultra-court (UTE) a été développée pour la visualisation in vivo des calcifications des artères coronariennes. Des études récentes ont démontré que les acquisitions UTE permettent de visualiser les calcifications dans des plaques athérosclérotiques ex vivo. Cepandent le mouvement du coeur a entravé jusqu'à maintenant l'utilisation des techniques UTE in vivo. Pour résoudre ce problème nous avons développé une séquence d'acquisition UTE avec trajectoire radiale 3D et l'avons testée sur des volontaires. La technique proposée utilise une auto-navigation 3D pour corriger le mouvement respiratoire et est synchronisée avec l'ECG. Trois échos sont acquis pour extraire le signal de la calcification avec des composants au T2 très court tout en permettant de séparer le signal de la graisse depuis le signal de l'eau. Les résultats sont encore préliminaires mais on peut affirmer que la technique développé peut potentiellement montrer les calcifications des artères coronariennes in vivo. En conclusion, ce travail de thèse présente trois nouvelles techniques pour l'IRM du coeur entier capables d'améliorer la visualisation et la caractérisation de la maladie athérosclérotique des coronaires. Ces techniques fournissent des informations anatomiques et fonctionnelles en quatre dimensions et des informations sur la composition du tissu auparavant indisponibles. CORONARY artery magnetic resonance imaging (MRI) has the potential to provide the cardiologist with relevant diagnostic information relative to coronary artery disease of patients. The major challenge of cardiac MRI, though, is dealing with all sources of motions that can corrupt the images affecting the diagnostic information provided. The current thesis, thus, focused on the development of new MRI techniques that change the standard approach to cardiac motion compensation in order to increase the efficiency of cardioavscular MRI, to provide more flexibility and robustness, new temporal information and new tissue information. The proposed approaches help in advancing coronary magnetic resonance angiography (MRA) in the direction of an easy-to-use and multipurpose tool that can be translated to the clinical environment. The first part of the thesis focused on the study of coronary artery motion through gold standard imaging techniques (x-ray angiography) in patients, in order to measure the precision with which the coronary arteries assume the same position beat after beat (coronary artery repositioning). We learned that intervals with minimal coronary artery repositioning occur in peak systole and in mid diastole and we responded with a new pulse sequence (T2~post) that is able to provide peak-systolic imaging. Such a sequence was tested in healthy volunteers and, from the image quality comparison, we learned that the proposed approach provides coronary artery visualization and contrast-to-noise ratio (CNR) comparable with the standard acquisition approach, but with increased signal-to-noise ratio (SNR). The second part of the thesis explored a completely new paradigm for whole- heart cardiovascular MRI. The proposed techniques acquires the data continuously (free-running), instead of being triggered, thus increasing the efficiency of the acquisition and providing four dimensional images of the whole heart, while respiratory self navigation allows for the scan to be performed in free breathing. This enabling technology allows for anatomical and functional evaluation in four dimensions, with high spatial and temporal resolution and without the need for contrast agent injection. The enabling step is the use of a golden-angle based 3D radial trajectory, which allows for a continuous sampling of the k-space and a retrospective selection of the timing parameters of the reconstructed dataset. The free-running 4D acquisition was then combined with a compressed sensing reconstruction algorithm that further increases the temporal resolution of the 4D dataset, while at the same time increasing the overall image quality by removing undersampling artifacts. The obtained 4D images provide visualization of the whole coronary artery tree in each phases of the cardiac cycle and, at the same time, allow for the assessment of the cardiac function with a single free- breathing scan. The quality of the coronary arteries provided by the frames of the free-running 4D acquisition is in line with the one obtained with the standard ECG-triggered one, and the cardiac function evaluation matched the one measured with gold-standard stack of 2D cine approaches. Finally, the last part of the thesis focused on the development of ultrashort echo time (UTE) acquisition scheme for in vivo detection of calcification in the coronary arteries. Recent studies showed that UTE imaging allows for the coronary artery plaque calcification ex vivo, since it is able to detect the short T2 components of the calcification. The heart motion, though, prevented this technique from being applied in vivo. An ECG-triggered self-navigated 3D radial triple- echo UTE acquisition has then been developed and tested in healthy volunteers. The proposed sequence combines a 3D self-navigation approach with a 3D radial UTE acquisition enabling data collection during free breathing. Three echoes are simultaneously acquired to extract the short T2 components of the calcification while a water and fat separation technique allows for proper visualization of the coronary arteries. Even though the results are still preliminary, the proposed sequence showed great potential for the in vivo visualization of coronary artery calcification. In conclusion, the thesis presents three novel MRI approaches aimed at improved characterization and assessment of atherosclerotic coronary artery disease. These approaches provide new anatomical and functional information in four dimensions, and support tissue characterization for coronary artery plaques.

Distinct OGT-Binding Sites Promote HCF-1 Cleavage.

Human HCF-1 (also referred to as HCFC-1) is a transcriptional co-regulator that undergoes a complex maturation process involving extensive O-GlcNAcylation and site-specific proteolysis. HCF-1 proteolysis results in two active, noncovalently associated HCF-1N and HCF-1C subunits that regulate distinct phases of the cell-division cycle. HCF-1 O-GlcNAcylation and site-specific proteolysis are both catalyzed by O-GlcNAc transferase (OGT), which thus displays an unusual dual enzymatic activity. OGT cleaves HCF-1 at six highly conserved 26 amino acid repeat sequences called HCF-1PRO repeats. Here we characterize the substrate requirements for OGT cleavage of HCF-1. We show that the HCF-1PRO-repeat cleavage signal possesses particular OGT-binding properties. The glutamate residue at the cleavage site that is intimately involved in the cleavage reaction specifically inhibits association with OGT and its bound cofactor UDP-GlcNAc. Further, we identify a novel OGT-binding sequence nearby the first HCF-1PRO-repeat cleavage signal that enhances cleavage. These results demonstrate that distinct OGT-binding sites in HCF-1 promote proteolysis, and provide novel insights into the mechanism of this unusual protease activity.

A Gradient based algorithm for blind inversion of Wiener System using multi-variate score functions

A Wiener system is a linear time-invariant filter, followed by an invertible nonlinear distortion. Assuming that the input signal is an independent and identically distributed (iid) sequence, we propose an algorithm for estimating the input signal only by observing the output of the Wiener system. The algorithm is based on minimizing the mutual information of the output samples, by means of a steepest descent gradient approach.