An Adaptive Remeshing Procedure for Proximity Maneuvering Spacecraft Formations

We consider a methodology to optimally obtain reconfigurations of spacecraft formations. It is based on the discretization of the time interval in subintervals (called the mesh) and the obtainment of local solutions on them as a result of a variational method. Applied to a libration point orbit scenario, in this work we focus on how to find optimal meshes using an adaptive remeshing procedure and on the determination of the parameter that governs it

Health Guidance Checklist for International Travelers, Tourists, and Missionaries, December 2010

This document is produced by Iowa Department of Public Health about a checklist of what people need to know about international travel.

Iowa Department of Transportation Office of Research & Analytics Guidance on Data Management Plan (DMP) Requirements for Federally Funded Research Projects

The Iowa Department of Transportation Office of Research & Analytics has created this Guide to help researchers and contractors of the Iowa DOT attain compliance with Federal and Iowa DOT Public Access Policies for transportation-related research publications and datasets. This guide provides direction for filling out the data management plan template (also attached to this record) that will help satisfy Iowa DOT and U.S. DOT requirements.

Bluetooth wireless technology based guidance system

Lyhyen kantaman langattomat kommunikaatioteknologiat tarjoavat mahdollisuuden toteuttaa erilaisia paikkasidonnaisia palveluita käyttäjille kohtuullisilla kustannuksilla. Opastejärjestelmä, joka ohjaa käyttäjän paikasta toiseen, on yksi tälläinen palvelu. Tässä työssä esitetään langattomaan Bluetooth teknologiaan perustuva opastejärjestelmä. Muita langattomia teknologioita verrataan Bluetoothiin opastejärjestelmän toteuttamisen kannalta. Erilaisia järjestelmän arkkitehtuuri vaihtoehtoja käyttäjän paikantamiseen esitellään. Paikkatietoja hyödynnetään opasteviestin muodostamisessa. Tapoja muodostaa käyttäjän reitti kahden paikan välillä toimistorakennuksessa esitetään. Työn tulos on halpa langatonta Bluetooth teknologiaa hyödyntävä opastejärjestelmä, jota voidaan käyttää myös muiden langattomien paikkasidonnaisten palveluiden tuottamiseen.

Practical guidance and considerations for transitioning patients from oxcarbazepine or carbamazepine to eslicarbazepine acetate--Expert opinion.

There is currently a lack of guidance on methodology and special considerations for transitioning patients from oxcarbazepine (OXC) or carbamazepine (CBZ) to eslicarbazepine acetate (ESL), if deemed clinically necessary. An advisory panel of epilepsy experts was convened to share their experience on the use of adjunctive ESL in clinical practice and to provide practical recommendations to help address this gap. When changing over from OXC to ESL, an OXC:ESL dose ratio of 1:1 should be employed to calculate the ESL target dose, and the changeover can take place overnight. No changes to comedication are required. Since CBZ has a different mechanism of action to ESL and is a stronger inducer of cytochrome P450 (CYP) enzymes, the transitioning of patients from CBZ to ESL requires careful consideration on a patient-by-patient basis. In general, a CBZ:ESL dose ratio of 1:1.3 should be employed to calculate the ESL target dose, and patients should be transitioned over a minimum period of 1-2weeks. Special considerations include adjustment of titration schedule and target dose in elderly patients and those with hepatic or renal impairment and potential adjustment of comedications metabolized by CYP enzymes. In summary, due to structural distinctions between ESL, OXC, and CBZ, which affect mechanism of action and tolerability, there are clinical situations in which it may be appropriate to consider transitioning patients from OXC or CBZ to ESL. Changing patients over from OXC to ESL is generally more straightforward than transitioning patients from CBZ to ESL, which requires careful consideration.

Missense mutations in TENM4, a regulator of axon guidance and central myelination, cause essential tremor.

Essential tremor (ET) is a common movement disorder with an estimated prevalence of 5% of the population aged over 65 years. In spite of intensive efforts, the genetic architecture of ET remains unknown. We used a combination of whole-exome sequencing and targeted resequencing in three ET families. In vitro and in vivo experiments in oligodendrocyte precursor cells and zebrafish were performed to test our findings. Whole-exome sequencing revealed a missense mutation in TENM4 segregating in an autosomal-dominant fashion in an ET family. Subsequent targeted resequencing of TENM4 led to the discovery of two novel missense mutations. Not only did these two mutations segregate with ET in two additional families, but we also observed significant over transmission of pathogenic TENM4 alleles across the three families. Consistent with a dominant mode of inheritance, in vitro analysis in oligodendrocyte precursor cells showed that mutant proteins mislocalize. Finally, expression of human mRNA harboring any of three patient mutations in zebrafish embryos induced defects in axon guidance, confirming a dominant-negative mode of action for these mutations. Our genetic and functional data, which is corroborated by the existence of a Tenm4 knockout mouse displaying an ET phenotype, implicates TENM4 in ET. Together with previous studies of TENM4 in model organisms, our studies intimate that processes regulating myelination in the central nervous system and axon guidance might be significant contributors to the genetic burden of this disorder.

Occlusal and dentofacial characteristics of the deciduous dentition and treatment effects of the eruption guidance appliance in the early mixed dentition

The aim of this investigation was to analyze the dental occlusion in the deciduous dentition, and the effects of orthodontic treatment carried out in the early mixed dentition with the eruption guidance appliance. The deciduous occlusion and craniofacial morphology of 486 children (244 girls and 242 boys) were investigated at the onset of the mixed dentition period (mean age 5.1 years, range 4.0-7.8 years). Treatment in the treatment group and follow-up in the control group were started when the first deciduous incisor was exfoliated (T1) and ended when all permanent incisors and first molars were fully erupted (T2). The mean age of the children was 5.1 years (SD 0.5) at T1 and 8.4 years (SD 0.5) at T2. Treatment was carried out with the eruption guidance appliance. Occlusal changes that took place in 167 children were compared with those of 104 untreated control children. Pre- and post-treatment cephalometric radiographs were taken, and the craniofacial morphology of 115 consecutively treated children was compared with that of 104 control children. The prevalence of malocclusion in the deciduous dentition was 68% or 93% depending on how the cut-off value between the acceptable and non-acceptable occlusal characteristic was defined. The early dentofacial features of children with distal occlusion, large overjet and deepbite differed from those with normal occlusion. However, the skeletal pattern of these three malocclusions showed considerable similarity each being characterized by a retrusive mandible, small maxillo-mandibular difference, convex profile, retrusive lower incisors, and large interincisal angle. In the treatment group, overjet and overbite decreased significantly from T1 to T2. Following treatment, a tooth-to-tooth contact was found in 99% of the treated children but only in 24% of the controls. A Class I molar relationship was observed in 90% of the children in the treatment group, and in 48% in the control group. Good alignment of the incisors was observed in 98% of the treated children, whereas upper crowding was found in 32% and lower crowding in 47% of the controls. A significant difference between the groups was found in the mandibular length, midfacial length and maxillo-mandibular differential. The occlusal correction, brought about by the eruption guidance appliance, was achieved mainly through changes in the dentoalveolar region of the mandible. In addition, the appliance seemed to enhance the growth of the mandible. Treatment in the early mixed dentition using the eruption guidance appliance is an effective method to normalize occlusion and reduce further need of orthodontic treatment. Only few spontaneous corrective changes can be expected without active intervention.

Numerics of Spacecraft Dynamics

Whenever a spacecraft is launched it is essential that the algorithms in the on-board software systems and at ground control are efficient and reliable over extended periods of time. Geometric numerical integrators, and in particular variational integrators, have both these characteristics. In "Numerics of Spacecraft Dynamics" new numerical integrators are presented and analysed in depth. These algorithms have been designed specifically for the dynamics of spacecraft and artificial satellites in Earth orbits. Full analytical solutions to a class of integrable deformations of the two-body problem in classical mechanics are derived, and a systematic method to compute variational integrators to arbitrary order with a computer algebra system is introduced.

Extracellular matrix molecules play diverse roles in the growth and guidance of central nervous system axons

Axon growth and guidance represent complex biological processes in which probably intervene diverse sets of molecular cues that allow for the appropriate wiring of the central nervous system (CNS). The extracellular matrix (ECM) represents a major contributor of molecular signals either diffusible or membrane-bound that may regulate different stages of neural development. Some of the brain ECM molecules form tridimensional structures (tunnels and boundaries) that appear during time- and space-regulated events, possibly playing relevant roles in the control of axon elongation and pathfinding. This short review focuses mainly on the recognized roles played by proteoglycans, laminin, fibronectin and tenascin in axonal development during ontogenesis.

Elucidation of the Retinoid Signalling Pathway Involved in Axon Guidance in Lymnaea stagnalis and Xenopus laevis

The vitamin A metabolite, retinoic acid (RA), is known to play a crucial role in several developmental processes including axial patterning and differentiation. More recently, RA has been implicated in the regenerative process acting through its classical signaling pathway, the nuclear receptors, retinoic acid receptor (RAR) and retinoid X receptor (RXR), to mediate gene transcription. Moreover, RA has been shown to act as a guidance molecule for growth cones of regenerating motorneurons of the pond snail, Lymnaea stagnalis. Our lab has recently shown that RA can induce this morphological response independent of nuclear transcription, however, the role of the retinoid receptors in RA-induced chemoattraction is still unknown. Here, I show that the retinoid receptors, RXR and RAR, may mediate the growth cones response to the metabolically active retinoic acid isomers, all-trans and 9-cis RA, in Lymnaea stagnalis. Data presented here show that both an RXR and RAR antagonist can block growth cone turning in response to application of both isomers. Because no prior investigations have shown growth cone turning of individual vertebrate neurons, I aimed to show that both retinoic acid isomers were capable of inducing growth cone turning of embryonic spinal cord neurons in the frog, Xenopus laevis. For the first time in Xenopus, I showed that both all-trans and 9-cis RA were able to induce significantly more neurite outgrowth from cultured embryonic spinal cord neurons and induce positive growth cone turning of individual growth cones. In addition, I showed that the presence of the RXR antagonist, HX531, blocked 9-cis RA-induced growth cone turning and the RARβ antagonist, LE135, blocked all-trans RA-induced growth cone turning in this species. Evidence provided here shows for the first time, conservation of retinoic acid-induced growth cone turning in a vertebrate model system. In addition, these data show that the receptors involved in this morphological response may be the same in vertebrates and invertebrates.

Maternal depression symptoms in early childhood and children's cognitive performance at school entry : the role of maternal guidance

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

The plant ovule omics : an integrative approach for pollen−pistil interactions and pollen tube guidance studies in solanaceous species

Chez les plantes à fleurs, l’ovaire est l’organe reproducteur femelle et il interagit de façon importante avec les gamètes mâles durant la croissance, le guidage, la réception et la rupture du tube pollinique ainsi que la fusion des gamètes. Le processus débute lorsque de nombreux gènes de l’ovule sont activés à longue distance lors de la réception du pollen sur le stigmate. Afin d’explorer les signaux provenant de l’ovule ayant un impact important sur les interactions pollen–pistil, particulièrement les molécules sécrétées impliquées dans la signalisation espècespécifique, l’expression génique des ovules sous forme d’ARNm ainsi et la sécrétion protéique ont été étudiées chez Solanum chacoense, une espèce diploïde de pomme de terre sauvage. S. chacoense a subi beaucoup d’hybridation interspécifique avec d’autres espèces sympathiques de solanacées, facilitant ainsi grandement l’étude des interactions pollen–ovule de façon espècespécifique ainsi que leur évolution. Dans ce projet, des ovules provenant de trois conditions différentes ont été comparés: des ovules matures de type sauvage, des ovules légèrement immatures, récoltés deux jours avant l’anthèse et des ovules provenant du mutant frk1 pour lesquels le sac embryonnaire est absent. Un séquençage d’ARN à haut débit a d’abord été effectué sur les ovules de type sauvage de S. chacoense afin de générer un assemblage de référence comprenant 33852 séquences codantes. D’autres séquençages ont été effectués sur les trois conditions d’ovules et sur les feuilles afin de faire une analyse d’expression différentielle des gènes. En comparaison avec les ovules de type sauvage, 818 gènes sont réprimés dans les ovules du mutant frk1. Un sous-groupe de 284 gènes, étaient également sous-exprimés dans les ovules légèrement immatures, suggérant un rôle spécifique dans les stades tardifs de la maturation du sac embryonnaire (stade de développent FG6 à FG7) ainsi que du guidage du tube pollinique, puisque ni les ovules du mutant frk1 ni ceux légèrement immatures ne sont capables d’attirer les tubes polliniques lors d’essais de croissance semi in vivo. De plus, 21% de ces gènes sont des peptides riches en cystéines (CRPs). En utilisant un transcriptome assemblé de novo provenant de deux proches parents de S. chacoense, S. gandarillasii et S. tarijense, une analyse d’orthologie a été effectuée sur ces CRPs, révélant une grande variabilité et une évolution rapide chez les solanacées. De nouveaux motifs de cystéine uniques à cette famille ont également été découverts. En comparant avec des études similaires chez Arabidopsis, le sac embryonnaire de S. chacoense montre un transcriptome fortement divergent, particulièrement en en ce qui a trait à la catégorisation fonctionnelle des gènes et de la similarité entre les gènes orthologues. De plus,même si la glycosylation n’est pas requise lors du guidage mycropylaire du tube pollinique chez Arabidopsis, Torenia ou le maïs, des extraits d’ovules glycosylés de S. chacoense sont capables d’augmenter la capacité de guidage de 18%. Cette étude est donc la première à montrer une corrélation entre glycosylation et le guidage du tube pollinique par l’ovule. En complément à l’approche transcriptomique, une approche protéomique portant sur les protéine sécrétées par l’ovule (le secrétome) a été utilisée afin d’identifier des protéines impliquées dans l’interaction entre ovule et tube pollinique. Des exsudats d’ovules matures (capables d’attirer le tube pollinique) et d’ovules immatures (incapables d’attirer le tube pollinique) ont été récoltés en utilisant une nouvelle méthode d’extraction par gravité permettant de réduire efficacement les contaminants cytosoliques à moins de 1% de l’échantillon. Un total de 305 protéines sécrétées par les ovules (OSPs) ont été identifiées par spectrométrie de masse, parmi lesquelles 58% étaient spécifiques aux ovules lorsque comparées avec des données de protéines sécrétées par des tissus végétatifs. De plus, la sécrétion de 128 OSPs est augmentée dans les ovules matures par rapport aux ovules immatures. Ces 128 protéines sont donc considérées en tant que candidates potentiellement impliquées dans la maturation tardive de l’ovule et dans le guidage du tube pollinique. Cette étude a également montré que la maturation du sac embryonnaire du stade FG6 au stade FG7 influence le niveau de sécrétion de 44% du sécrétome total de l’ovule. De façon surprenante, la grande majorité (83%) de ces protéines n’est pas régulée au niveau de l’ARN, soulignant ainsi l’importance de cette approche dans l’étude du guidage du tube pollinique comme complément essentiel aux études transcriptomiques. Parmi tous les signaux sécrétés par l’ovule et reliés au guidage, obtenus à partir des approches transcriptomiques et protéomiques décrites ci-haut, nous avons spécifiquement évalué l’implication des CRPs dans le guidage du tube pollinique par l’ovule chez S. chacoense, vu l’implication de ce type de protéine dans les interactions pollen-pistil et le guidage du tube pollinique chez d’autres espèces. Au total, 28 CRPs étaient présentes dans les ovules capables d’attirer le tube pollinique tout en étant absentes dans les ovules incapables de l’attirer, et ce, soit au niveau de l’ARNm et/ou au niveau du sécrétome. De celles-ci, 17 CRPs ont été exprimées dans un système bactérien et purifiées en quantité suffisante pour tester le guidage. Alors que des exsudats d’ovules ont été utilisés avec succès pour attirer par chimiotactisme le tube pollinique, les candidats exprimés dans les bactéries n’ont quant à eux pas été capables d’attirer les tubes polliniques. Comme l’utilisation de systèmes d’expression hétérologue eucaryote peut permettre un meilleur repliement et une plus grande activité des protéines, les candidats restants seront de nouveau exprimés, cette fois dans un système de levure ainsi que dans un système végétal pour produire les peptides sécrétés. Ceux-ci seront ensuite utilisés lors d’essais fonctionnels pour évaluer leur capacité à guider les tubes polliniques et ainsi isoler les attractants chimiques responsable du guidage du tube pollinique chez les solanacées comme S. chacoense.

A Novel Slotless Halbach-Array Permanent-Magnet Brushless DC Motor for Spacecraft Applications

This paper presents the design and analysis of a novel machine family—the enclosed-rotor Halbach-array permanentmagnet brushless dcmotors for spacecraft applications. The initial design, selection of major parameters, and air-gap magnetic flux density are estimated using the analytical model of the machine. The proportion of the Halbach array in the machine is optimized using finite element analysis to obtain a near-trapezoidal flux pattern. The machine is found to provide uniform air-gap flux density along the radius, thus avoiding circulating currents in stator conductors and thereby reducing torque ripple. Furthermore, the design is validated with experimental results on a fabricated machine and is found to suit the design requirements of critical spacecraft applications