Static postural balance study in patients with vestibular disorders using a three dimensional eletromagnetic sensor system

The vestibular-ocular reflex assessment is important, but not enough. Tridimensional electromagnetic sensor systems represent a new method to assess posturography. Aim: To assess body sway in healthy subjects who had positive Dix Hallpike and Epley maneuvers and with other vestibular dysfunctions by means of a three-dimensional system. Study design: Prospective. Materials and Methods: We had 23 healthy women, 15 with peripheral vestibular dysfunction found upon caloric test and 10 with positive Epley and Dix Hallpike maneuvers. All tests performed in the following positions: open and closed eyes on stable and unstable surfaces. Results: With the Eyes Open and on a stable surface, p < 0.01 between the control group and the one with peripheral vestibular dysfunction in all variables, except the a-p maximum, full speed and mediolateral trajectory velocity, which had a p < 0.01 between the group with vestibular dysfunction and controls in all positions. The group with positive Epley and Dix Hallpike maneuvers had p < 0.01 at full speed and in its components in the x and y in positions with open and eyes closed on an unstable surface. Conclusion: The tridimensional electromagnetic sensors system was able to generate reliable information about body sway in the study volunteers.

Obese elderly women exhibit low postural stability: a novel three-dimensional evaluation system

OBJECTIVE: The aim of this study was to evaluate the multisegmental static postural balance of active eutrophic and obese elderly women using a three-dimensional system under different sensory conditions. METHODS: A cross-sectional study was conducted on 31 elderly women (16 eutrophic and 15 obese) aged 65 to 75 years. The following anthropometric measurements were obtained: weight, height, waist and hip circumference, and handgrip strength. The physical activity level was evaluated using the International Physical Activity Questionnaire. Body composition was measured using the deuterium oxide dilution technique. The Polhemus (R) Patriot (three-dimensional) equipment was used to measure the parameters of postural balance along the anteroposterior and laterolateral axes. The data acquisition involved one trial of 60 s to test the limit of stability and four trials of 90 s each under the following conditions: (1) eyes open, stable surface; (2) eyes closed, stable surface; (3) eyes open, unstable surface; and (4) eyes closed, unstable surface. RESULTS: For the limit of stability, significant differences were observed in the maximum anteroposterior and laterolateral displacement (p<0.01) and in the parameter maximum anteroposterior displacement in the eyes closed stable surface condition (p<0.01) and maximum anteroposterior and laterolateral displacement in the eyes open unstable surface (p<0.01 and p = 0.03) and eyes closed unstable surface (p<0.01 and p<0.01) conditions. CONCLUSIONS: Obese elderly women exhibited a lower stability limit (lower sway area) compared with eutrophic women, leaving them more vulnerable to falls.

Isolated GH deficiency type II: knockdown of the harmful Delta3GH recovers wt-GH secretion in rat tumor pituitary cells

Isolated GH deficiency type II (IGHD II) is the autosomal dominant form of GHD. In the majority of the cases, this disorder is due to specific GH-1 gene mutations that lead to mRNA missplicing and subsequent loss of exon 3 sequences. When misspliced RNA is translated, it produces a toxic 17.5-kDa GH (Delta3GH) isoform that reduces the accumulation and secretion of wild-type-GH. At present, patients suffering from this type of disease are treated with daily injections of recombinant human GH in order to maintain normal growth. However, this type of replacement therapy does not prevent toxic effects of the Delta3GH mutant on the pituitary gland, which can eventually lead to other hormonal deficiencies. We developed a strategy involving Delta3GH isoform knockdown mediated by expression of a microRNA-30-adapted short hairpin RNA (shRNA) specifically targeting the Delta3GH mRNA of human (shRNAmir-Delta3). Rat pituitary tumor GC cells expressing Delta3GH upon doxycycline induction were transduced with shRNAmir-Delta3 lentiviral vectors, which significantly reduced Delta3GH protein levels and improved human wild-type-GH secretion in comparison with a shRNAmir targeting a scrambled sequence. No toxicity due to shRNAmir expression could be observed in cell proliferation assays. Confocal microscopy strongly suggested that shRNAmir-Delta3 enabled the recovery of GH granule storage and secretory capacity. These viral vectors have shown their ability to stably integrate, express shRNAmir, and rescue IGHD II phenotype in rat pituitary tumor GC cells, a methodology that opens new perspectives for the development of gene therapy to treat IGHD patients.

Native bradyrhizobial symbionts of Lupinus mariae-josephae, a unique endemism thriving in alkaline soils in Eastern Spain

Lupinus mariae-josephae (Lmj) es una especie de lupino endémica de una pequeña y específica área de Comunidad Valenciana (Este de España), donde prospera en suelos alcalinoscalcáreos, un hábitat singular para los altramuces, que crecen preferentemente en suelos ácidos o neutros. Esto hace de Lmj una especie de lupino única. Cuando se inició este trabajo, la extensión conocida de este endemismo abarcaba unos 700 kilómetros cuadrados, confinados en la provincia de Valencia. En esta área, Lmj prospera en pequeñas poblaciones aisladas que contienen un número reducido de plantas por lo que se la consideró una especie en peligro de extinción. Todos los esfuerzos, utilizando estrategias clásicas dirigidas a ampliar el área de crecimiento de Lmj y garantizar su conservación, han tenido un éxito limitado. El trabajo que se presenta está dirigido a mejorar el conocimiento de la ecología de Lmj, en particular la interacción simbiótica que establece con bacterias del suelo denominadas rizobios y se centra en la caracterización fenotípica, filogenética y genómica de esos rizobios. También se investiga la posible contribución de la simbiosis en mejorar la conservación de Lmj. Para este fin, se han estudiado diferentes aspectos que se describen a continuación. El primero objetivo se centró en aislar y estudiar de la diversidad genética de las bacterias endosimbióticas de Lmj. . Se realizó un análisis filogenético de genes esenciales que mostró que las cepas de Lmj pertenecen al género Bradyrhizobium y que presentan una gran diversidad con características fenotípicas y simbióticas diferentes de cepas de Bradyrhizobium que nodulan otras especies de lupinos nativos de España (cepas ISLU). Las cepas estudiadas se dividieron en dos grupos (Clado I y Clado II). El Clado I, incluye a las cepas Lmj, definiendo un nuevo linaje, filogenéticamente relacionado con otras especies de Bradyrhizobium, como B. jicamae y B. elkanii. El Clado II contiene cepas ISLU relacionadas con cepas de B. canariense y B. japonicum que establecen simbiosis con lupinos de suelos ácidos. Otro análisis filogenético basado en genes simbióticos, distribuyó las cepas de Lmj en sólo dos grupos diferentes. La singularidad y gran diversidad de estas cepas en una pequeña área geográfica, hacen de este, un atractivo sistema para el estudio de la evolución y adaptación de las bacterias simbióticas a su respectiva planta huésped. Adicionalmente, se estudio la presencia de bacterias capaces de nodular Lmj en suelos básicos de Chiapas, México. Sorprendentemente, estos suelos contienen bacterias capaces establecer interacciones simbióticas eficientes con Lmj en ensayos de invernadero. A continuación se investigó la taxonomía de los endosimbiontes de Lmj analizando la secuencia de cuatro genes esenciales (16S rRNA, recA, glnII y atpD) y el promedio de identidad de nucleótidos de genomas completos de algunas cepas representativas de la diversidad (ANIm). Se identificaron nuevas especies de Bradyrhizobium dentro del Clado I y se definió una de ellas: 'Bradyrhizobium valentinum' sp. nov (cepa tipo LmjM3T = CECT 8364T, LMG 2761T). También se abordó cómo conservar Lmj en su hábitat natural mediante inoculación con alguna de las cepas aisladas. Se demostró la ausencia de bacterias capaces de nodular Lmj en suelos rojos alcalinos o ‘‘terra rossa’’ de la Península Ibérica y Baleares. Dos cepas, altamente eficientes en cuanto a la fijación de nitrógeno, LmjC y LmjM3T, fueron seleccionadas para ser empleadas como inoculantes. Dos experimentos de campo llevados a cabo en años consecutivos en áreas con características edafoclimáticas similares a las que presentan las poblaciones de Lmj, lograron la reproducción exitosa de la planta. Se concluyó que un ciclo reproductivo exitoso de Lmj es absolutamente dependiente de la inoculación con sus simbiontes naturales y que la simbiosis debe ser considerada un factor esencial en estrategias de conservación de leguminosas en peligro. La obtención de varias secuencias genómicas de cepas aisladas de Lmj y de otras cepas de Bradyrhizobium reveló una alta similitud entre los genomas de las cepas del Clado I, y permitió la identificación de cinco posibles nuevas especies. Además, se estudiaron tres agrupaciones de genes relacionados con la simbiosis (nod, nif y fix) definiendo un nuevo linaje para las cepas de Lmj, diferente del symbiovar “genistearum” de B. canariense y B. japonicum. La baja diversidad encontrada en el análisis filogenético de los genes simbióticos contrasta con la gran diversidad asociada a genes esenciales. La presencia de plásmidos en cepas del género Bradyrhizobium ha sido descrita en muy pocas ocasiones, sin embargo el análisis de la secuencia genómica de la cepa ISLU101, aislada de Lupinus angustifolius, reveló la presencia de un origen de replicación extracromosómico homólogo al operón repABC, presente en el plásmido de Bradyrhizobium sp BTAi1. Gracias a esta secuencia se identificaron genes homólogos en 19 de 72 cepas ISLU. Filogenéticamente, las secuencias de repABC se agruparon en un grupo monofilético con las de pBTAi1 y separadas de los rizobios de crecimiento rápido. Finalmente, se identificaron sistemas de secreción de proteínas de tipo III (T3SS) en nueve genomas de cepas de Lmj. Los T3SS pueden inyectar proteínas efectoras al interior de células vegetales. Su presencia en rizobios se ha relacionado con la gama de hospedador que pueden nodular y puede tener un efecto beneficioso, neutro o perjudicial en la simbiosis. Los T3SS de las cepas de Lmj codifican para una proteína efectora similar a NopE, un efector dependiente de T3SS descrito en B. diazoefficiens USDA 110T. La proteína NopE de la cepa LmjC se ha caracterizado bioquímicamente. ABSTRACT Lupinus mariae-josephae (Lmj) is a lupine species endemic of a unique small area in Valencia region (Eastern Spain) where the lupine plants thrive in alkaline-limed soils, which preferentially grow in acid or neutral soils. This is the type of soils native lupines of Spain. When this work was initiated, the extension of the endemic area of Lmj was of about 700 squared kilometers confined to the Valencia province. In this area, Lmj thrives in small, isolated patches containing a reduced number of plants, and points to an endemism that can easily became endangered or extinct. Consequently, the Valencia Community authorities gave a ‘‘microreserve” status for conservation of the species. All efforts, using classical strategies directed to extend the area of Lmj growth and ensure its conservation have been so far unsuccessful. The work presented here is directed to improve our knowledge of Lmj ecology and it is centered in the characterization of the rhizobial symbiosis by phenotypic, phylogenetic and genomic analysis as well as in investigate the potential contribution of the symbiosis to improve its conservation. To this end, five different topics have been studied, and results are briefly described here. Extensive details can be followed en the attached, published articles. The first topic deals with the indigenous rhizobial symbionts of the Lmj endemism, and its genetic diversity was investigated. The Lmj root symbionts belong to the Bradyrhizobium genus, and phylogenetic analysis based on core genes identified a large diversity of Bradyrhizobium strains with phenotypic and symbiotic characteristics different from rhizobia nodulating other Lupinus spp. native of Spain. The strains were split in two clades. Clade II contained strains close to classical B. canariense and B. japonicum lineages that establish symbioses with lupines in acid soils of the Mediterranean area. Clade I included Lmj strains that define a new lineage, close to other Bradyrhizobium species as B. jicamae and B. elkanii. The phylogenetic analysis based on symbiotic genes identified only two distinct clusters. The singularity and large diversity of these strains in such a small geographical area makes this an attractive system for studying the evolution and adaptation of the rhizobial symbiont to the plant host. Additionally, the presence of bacteria able to nodulate Lmj in basic soils from Chiapas, Mexico was investigated. Surprisingly, these soils contain bacteria able to effectively nodulate and fix nitrogen with Lmj plants in greenhouse assays. In the second topic, the taxonomic status of the endosymbiotic bacteria of Lmj from Valencia endemism and Chiapas was investigated. Results from phylogenetic analysis of core genes and Average Nucleotide Identity (ANIm) using draft genomic sequences identified new Bradyrhizobium species within strains of Clade I of Lmj endosymbiotic bacteria. Only one of these potentially new species has been defined, meanwhile the others are under process of characterization. The name ‘Bradyrhizobium valentinum’ sp. nov. was proposed for the defined species (type strain LmjM3T= CECT 8364T, LMG 2761T). The third topic was directed to conservation of endangered Lmj in its natural habitat. The relevant conclusion of this experimentation is that the symbiosis should be considered as a relevant factor in the conservation strategies for endangered legumes. First, we showed absence of bacteria able to nodulate Lmj in all the inspected ‘‘terra rossa’’ or alkaline red soils of the Iberian Peninsula and Balearic Islands. Then, two efficient nitrogen fixing strains with Lmj plants, LmjC and LmjM3T, were selected as inoculum for seed coating. Two planting experiments were carried out in consecutive years under natural conditions in areas with edapho-climatic characteristics identical to those sustaining natural Lmj populations, and successful reproduction of the plant was achieved. The relevant conclusion from these assays was that the successful reproductive cycle was absolutely dependent on seedling inoculation with effective bradyrhizobia The forth topic deep into the analysis of the genomic of Lmj representative strains. To this end, draft genomic sequences of selected Lmj strains and type strains of Bradyrhizobium spp. were assembled. The comparison analysis of the draft genomic sequences of Lmj strains and related Bradyrhizobium species grouped in Clade I, revealed a high genomic homology among them, and allowed the definition of five potentially new species of Lmj nodulating bacteria. Also, based on the available draft genomic sequences, only three clusters of nod, fix and nif genes from Lmj strains were identified and showed to define a new symbiotic lineage, distant from that of B. canariense and B. japonicum bv. genistearum. The low diversity exhibited by the phylogenetic analysis of symbiotic genes contrast with the large diversity of strains as regards the housekeeping genes analyzed. Besides, the genomic analysis of a Lupinus angustifolius strain ISLU101, revealed the presence of an extrachromosomal replication origin homologous to repABC cluster from plasmid present in Bradyrhizobium spp BTAi1. This repABC cluster gene sequence allowed the identification of extrachromosomic replication origin in 19 out of 72 Bradyrhizobium strains from Lupinus spp., a highly significant result since the absence of plasmids in the Bradyrhizobium genus was traditionally assumed. The repABC gene sequences of these strains grouped them in a unique monophyletic group, related to B. sp. BTAi1 plasmid, but differentiated from the repABC gene cluster of plasmids in fast growing rhizobium strains. The last topic was focused on characterization of type III secreted effectors present in Lmj endosymbiotic bacteria. Type III secretion systems (T3SS) are specialized protein export machineries which can deliver effector proteins into plant cells. The presence of T3SS in rhizobia has frequently been related to the symbiotic nodulation host-range and may have a beneficial or detrimental effect on the symbiosis with legumes. In this context, the presence of T3SS in genomes of nine Lmj strains was investigated, and it was shown the presence of clusters encoding NopE type III-secreted protein similar to the NopE1 and NopE2 of B. diazoefficiens USDA 110T. The putative NopE protein of LmjC strain is at present being characterized regarding its structure and function.

Reciprocal secretion of proteins by the bacterial type III machines of plant and animal pathogens suggests universal recognition of mRNA targeting signals

Bacterial pathogens of both animals and plants use type III secretion machines to inject virulence proteins into host cells. Although many components of the secretion machinery are conserved among different bacterial species, the substrates for their type III pathways are not. The Yersinia type III machinery recognizes some secretion substrates via a signal that is encoded within the first 15 codons of yop mRNA. These signals can be altered by frameshift mutations without affecting secretion of the encoded polypeptides, suggesting a mechanism whereby translation of yop mRNA is coupled to the translocation of newly synthesized polypeptide. We report that the type III machinery of Erwinia chrysanthemi cloned in Escherichia coli recognizes the secretion signals of yopE and yopQ. Pseudomonas syringae AvrB and AvrPto, two proteins exported by the recombinant Erwinia machine, can also be secreted by the Yersinia type III pathway. Mapping AvrPto sequences sufficient for the secretion of reporter fusions in Yersinia revealed the presence of an mRNA secretion signal. We propose that 11 conserved components of type III secretion machines may recognize signals that couple mRNA translation to polypeptide secretion.

cag, a pathogenicity island of Helicobacter pylori, encodes type I-specific and disease-associated virulence factors

cagA, a gene that codes for an immunodominant antigen, is present only in Helicobacter pylori strains that are associated with severe forms of gastroduodenal disease (type I strains). We found that the genetic locus that contains cagA (cag) is part of a 40-kb DNA insertion that likely was acquired horizontally and integrated into the chromosomal glutamate racemase gene. This pathogenicity island is flanked by direct repeats of 31 bp. In some strains, cag is split into a right segment (cagI) and a left segment (cagII) by a novel insertion sequence (IS605). In a minority of H. pylori strains, cagI and cagII are separated by an intervening chromosomal sequence. Nucleotide sequencing of the 23,508 base pairs that form the cagI region and the extreme 3′ end of the cagII region reveals the presence of 19 ORFs that code for proteins predicted to be mostly membrane associated with one gene (cagE), which is similar to the toxin-secretion gene of Bordetella pertussis, ptlC, and the transport systems required for plasmid transfer, including the virB4 gene of Agrobacterium tumefaciens. Transposon inactivation of several of the cagI genes abolishes induction of IL-8 expression in gastric epithelial cell lines. Thus, we believe the cag region may encode a novel H. pylori secretion system for the export of virulence determinants.

Phylogeny of genes for secretion NTPases: Identification of the widespread tadA subfamily and development of a diagnostic key for gene classification

Macromolecular transport systems in bacteria currently are classified by function and sequence comparisons into five basic types. In this classification system, type II and type IV secretion systems both possess members of a superfamily of genes for putative NTP hydrolase (NTPase) proteins that are strikingly similar in structure, function, and sequence. These include VirB11, TrbB, TraG, GspE, PilB, PilT, and ComG1. The predicted protein product of tadA, a recently discovered gene required for tenacious adherence of Actinobacillus actinomycetemcomitans, also has significant sequence similarity to members of this superfamily and to several unclassified and uncharacterized gene products of both Archaea and Bacteria. To understand the relationship of tadA and tadA-like genes to those encoding the putative NTPases of type II/IV secretion, we used a phylogenetic approach to obtain a genealogy of 148 NTPase genes and reconstruct a scenario of gene superfamily evolution. In this phylogeny, clear distinctions can be made between type II and type IV families and their constituent subfamilies. In addition, the subgroup containing tadA constitutes a novel and extremely widespread subfamily of the family encompassing all putative NTPases of type IV secretion systems. We report diagnostic amino acid residue positions for each major monophyletic family and subfamily in the phylogenetic tree, and we propose an easy method for precisely classifying and naming putative NTPase genes based on phylogeny. This molecular key-based method can be applied to other gene superfamilies and represents a valuable tool for genome analysis.

The impact of information technology on organizations: A study of enterprise resource planning system influences on job design and organizational culture

The primary purpose of this research is to study the linkage between perceived job design characteristics and information system environment characteristics before and after the replacement of a legacy information system with a new type of information system (referred to as an Enterprise Resource Planning or ERP system). A public state University implementing an academic version of an ERP system was selected for the study. Three survey instruments were used to examine the perception of the information system, the job characteristics, and the organizational culture before and after the system implementation. The research participants included two large departments resulting in a sample of 130 workers. Research questions were analyzed using multivariate procedures including factor analysis, path analysis, step-wise regression, and matched pair analysis. ^ Results indicated that the ERP system has introduced new elements into the working environment that has changed the perception of how the job design characteristics and organization culture dimensions are viewed by the workers. The understanding of how the perceived system characteristics align with an individual's perceived job design characteristics is supported by each of the system characteristics significantly correlated in the proposed direction. The stronger support of this relationship becomes visible in the causal flow of the effects seen in the path diagram and in the step-wise regression. The perceived job design characteristics aligning with dimensions of organizational culture are not as strong as the literature suggests. Although there are significant correlations between the job and culture variables, only one relationship can be seen in the causal flow. ^ This research has demonstrated that system characteristics of ERP do contribute to the perception of change in an organization and do support organizational culture behaviors and job characteristics. ^

IntelliChair: a non-intrusive sitting posture and sitting activity recognition system

Current Ambient Intelligence and Intelligent Environment research focuses on the interpretation of a subject’s behaviour at the activity level by logging the Activity of Daily Living (ADL) such as eating, cooking, etc. In general, the sensors employed (e.g. PIR sensors, contact sensors) provide low resolution information. Meanwhile, the expansion of ubiquitous computing allows researchers to gather additional information from different types of sensor which is possible to improve activity analysis. Based on the previous research about sitting posture detection, this research attempts to further analyses human sitting activity. The aim of this research is to use non-intrusive low cost pressure sensor embedded chair system to recognize a subject’s activity by using their detected postures. There are three steps for this research, the first step is to find a hardware solution for low cost sitting posture detection, second step is to find a suitable strategy of sitting posture detection and the last step is to correlate the time-ordered sitting posture sequences with sitting activity. The author initiated a prototype type of sensing system called IntelliChair for sitting posture detection. Two experiments are proceeded in order to determine the hardware architecture of IntelliChair system. The prototype looks at the sensor selection and integration of various sensor and indicates the best for a low cost, non-intrusive system. Subsequently, this research implements signal process theory to explore the frequency feature of sitting posture, for the purpose of determining a suitable sampling rate for IntelliChair system. For second and third step, ten subjects are recruited for the sitting posture data and sitting activity data collection. The former dataset is collected byasking subjects to perform certain pre-defined sitting postures on IntelliChair and it is used for posture recognition experiment. The latter dataset is collected by asking the subjects to perform their normal sitting activity routine on IntelliChair for four hours, and the dataset is used for activity modelling and recognition experiment. For the posture recognition experiment, two Support Vector Machine (SVM) based classifiers are trained (one for spine postures and the other one for leg postures), and their performance evaluated. Hidden Markov Model is utilized for sitting activity modelling and recognition in order to establish the selected sitting activities from sitting posture sequences.2. After experimenting with possible sensors, Force Sensing Resistor (FSR) is selected as the pressure sensing unit for IntelliChair. Eight FSRs are mounted on the seat and back of a chair to gather haptic (i.e., touch-based) posture information. Furthermore, the research explores the possibility of using alternative non-intrusive sensing technology (i.e. vision based Kinect Sensor from Microsoft) and find out the Kinect sensor is not reliable for sitting posture detection due to the joint drifting problem. A suitable sampling rate for IntelliChair is determined according to the experiment result which is 6 Hz. The posture classification performance shows that the SVM based classifier is robust to “familiar” subject data (accuracy is 99.8% with spine postures and 99.9% with leg postures). When dealing with “unfamiliar” subject data, the accuracy is 80.7% for spine posture classification and 42.3% for leg posture classification. The result of activity recognition achieves 41.27% accuracy among four selected activities (i.e. relax, play game, working with PC and watching video). The result of this thesis shows that different individual body characteristics and sitting habits influence both sitting posture and sitting activity recognition. In this case, it suggests that IntelliChair is suitable for individual usage but a training stage is required.

Aspectos ultra-estruturais dos canais secretores em órgãos vegetativos e reprodutivos de Anacardiaceae

The study assessed phloem canal development and ultra-structure in shoot apices of Spondias dulcis G. Forst., phloematic canal ultra-structure in shoot apices of Tapirira guianensis Aubl., and floral canal ultra-structure and development and fruit canal ultra-structure of the latter specie. The flower and fruit canals of Anacardium humile St.Hil. were also studied ultra-structurally. The canals in shoot apices of S. dulcis show schizo-lysigenous formation and the floral canals of T. guianensis show schizogenous development. Epithelial cells of S. dulcis and T. guianensis canals have rough endoplasmic reticulum, free ribosomes, elongated plastids of several shapes with osmiophilic inclusions and dictyosomes with production of vesicles. Such organelles participate in the secretion of a heterogeneous exudate, which is comprised of hydrophilic and lipophilic substances. The epithelial cells of the fruit of A. humile present elongated plastids with circular membrane system, which are involved in the synthesis of lipophilic substances. The results of the ultra-structural analyses of the epithelial cells corroborate the results previously obtained in a histochemical study. In the histochemical study, lipophilic and hydrophilic substances were identified in the canals of T. guinanensis and S. dulcis and only lipophilic substances were identified in the canals of A. humile. Based on the ultrastructural aspects of the secretory canals of T. guianensis and S. dulcis we concluded that the plastids of the epithelial cells of the two species are different although they produce secretion of similar composition. A new record for the family is the presence of a great number of circular plastids in epithelial cells of the fruit of Anacardium humile. The pattern found in the secretory canals of the studied species is the ecrine type of secretion release.

Novel insights into the genomic basis of citrus canker based on the genome sequences of two strains of Xanthomonas fuscans subsp aurantifolii

Background: Citrus canker is a disease that has severe economic impact on the citrus industry worldwide. There are three types of canker, called A, B, and C. The three types have different phenotypes and affect different citrus species. The causative agent for type A is Xanthomonas citri subsp. citri, whose genome sequence was made available in 2002. Xanthomonas fuscans subsp. aurantifolii strain B causes canker B and Xanthomonas fuscans subsp. aurantifolii strain C causes canker C. Results: We have sequenced the genomes of strains B and C to draft status. We have compared their genomic content to X. citri subsp. citri and to other Xanthomonas genomes, with special emphasis on type III secreted effector repertoires. In addition to pthA, already known to be present in all three citrus canker strains, two additional effector genes, xopE3 and xopAI, are also present in all three strains and are both located on the same putative genomic island. These two effector genes, along with one other effector-like gene in the same region, are thus good candidates for being pathogenicity factors on citrus. Numerous gene content differences also exist between the three cankers strains, which can be correlated with their different virulence and host range. Particular attention was placed on the analysis of genes involved in biofilm formation and quorum sensing, type IV secretion, flagellum synthesis and motility, lipopolysacharide synthesis, and on the gene xacPNP, which codes for a natriuretic protein. Conclusion: We have uncovered numerous commonalities and differences in gene content between the genomes of the pathogenic agents causing citrus canker A, B, and C and other Xanthomonas genomes. Molecular genetics can now be employed to determine the role of these genes in plant-microbe interactions. The gained knowledge will be instrumental for improving citrus canker control.

Decoherence and coherent population transfer between two coupled systems

We show that an arbitrary system described by two dipole moments exhibits coherent superpositions of internal states that can be completely decoupled fi om the dissipative interactions (responsible for decoherence) and an external driving laser field. These superpositions, known as dark or trapping states, can he completely stable or can coherently interact with the remaining states. We examine the master equation describing the dissipative evolution of the system and identify conditions for population trapping and also classify processes that can transfer the population to these undriven and nondecaying states. It is shown that coherent transfers are possible only if the two systems are nonidentical, that is the transitions have different frequencies and/or decay rates. in particular, we find that the trapping conditions can involve both coherent and dissipative interactions, and depending on the energy level structure of the system, the population can be trapped in a linear superposition of two or more bare states, a dressed state corresponding to an eigenstate of the system plus external fields or, in some cases. in one of the excited states of the system. A comprehensive analysis is presented of the different processes that are responsible for population trapping, and we illustrate these ideas with three examples of two coupled systems: single V- and Lambda-type three-level atoms and two nonidentical tao-level atoms, which are known to exhibit dark states. We show that the effect of population trapping does not necessarily require decoupling of the antisymmetric superposition from the dissipative interactions. We also find that the vacuum-induced coherent coupling between the systems could be easily observed in Lambda-type atoms. Our analysis of the population trapping in two nonidentical atoms shows that the atoms can be driven into a maximally entangled state which is completely decoupled from the dissipative interaction.

Ultra-compact dwarf galaxies: a new class of compact stellar system discovered in the Fornax Cluster

We have used the 2dF spectrograph on the Anglo-Australian Telescope to obtain a complete spectroscopic sample of all objects in the magnitude range, 16.5 < bj < 19.8, regardless of morphology, in an area centred on the Fornax Cluster of galaxies. Among the unresolved targets are five objects which are members of the Fornax Cluster. They are extremely compact stellar systems with scale lengths less than 40 parsecs. These ultra-compact dwarfs are unlike any known type of stellar system, being more compact and significantly less luminous than other compact dwarf galaxies, yet much brighter than any globular cluster.

Construção de um robô trepador com locomoção através de rodas e adesão através de meios magnéticos

Mestrado em Engenharia Electrotécnica e de Computadores

Estudo de caso de malformação congénita, com quantificação do êmbolo em 4 sistemas de suspensão para próteses endosqueléticas transtibiais com encaixe TSB

Introdução – O efeito de êmbolo é um dos principais problemas relacionados com a eficácia de uma prótese. Uma diminuição do mesmo pode levar a uma marcha mais natural através do aumento da propriocetividade. Objetivos – Verificar se existe diferença de valores do efeito de êmbolo entre vários sistemas de suspensão para próteses transtibiais com a utilização de Liners e testar a aplicação de testes de imagiologia na análise da melhor solução protésica para um determinado indivíduo. Metodologia – Foi obtida uma radiografia da prótese em carga na posição ortostática, mantendo o peso do indivíduo igualmente distribuído pelos dois pés. Seguidamente foi realizada outra radiografia no plano sagital com o joelho com 30° de flexão, com a prótese suspensa e um peso de 5kg aplicado na extremidade distal da mesma durante 30 seg. Através destes dois exames efetuaram-se as medições do êmbolo para cada tipo de sistema de suspensão. Resultados – Dos quatro sistemas estudados apenas três apresentam valores de êmbolo, visto que um dos sistemas não criou suspensão suficiente para suportar o peso colocado na extremidade distal da prótese. Através das medições realizadas nos exames imagiológicos dos três sistemas pudemos encontrar variações de efeito de êmbolo que vão dos 47,91mm aos 72,55mm. Conclusão – Através da realização do estudo imagiológico verificaram-se diferenças a nível do efeito de êmbolo nos vários sistemas de suspensão, provando que esta é uma ferramenta viável na avaliação do mesmo. Também através da análise dos resultados ficou notório que o sistema de suspensão Vacuum Assisted Suspention System (VASS) é o que apresenta menos êmbolo.