949 resultados para Ball Carries
Resumo:
Nove espécies são transferidas de Portanus Ball, 1932 para Paraportanus gen. nov.: Paraportanus longicornis (Osborn, 1923) comb. nov. = Portanus chelatus DeLong, 1976 syn. nov.; Paraportanus elegans (Kramer, 1961) comb. nov.; Paraportanus facetus (Kramer, 1961) comb. nov.; Paraportanus eburatus (Kamer, 1964) comb. nov.; Paraportanus filamentus (DeLong, 1980) comb. nov.; Paraportanus bicornis (Carvalho & Cavichioli, 2003) comb. nov.; Paraportanus bimaculatus (Carvalho & Cavichioli, 2003) comb. nov.; Paraportanus cinctus (Carvalho & Cavichioli, 2003) comb. nov.; Paraportanus variatus (Carvalho & Cavichioli, 2003) comb. nov.. Novos dados de distribuição geográfica são registrados para: P. facetus; P. elegans e P. longicornis. Chave para identificação das espécies é apresentada.
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Abstract Telomeres, the natural ends of chromosomes, need to be protected from chromosome end fusions, aberrant homologous recombination and degradation. In humans, chromosome ends are specified through arrays of tandemly repeated 5'-TTAGGG-3' hexamers, ending in a 3' overhang. A complex formed by the six proteins TRF1, TRF2, hRap1, TIN2, TPP1 and POT1 specifically assocìates with and protects telomeres. Telomeres are maintained by semiconservative DNA replication and by a specialized reverse transcriptase, telomerase, that carries an RNA subunit which templates new telomeric repeat synthesis. The telomeric single stranded (ss) DNA binding protein POT1 protects the telomeric 3' overhang and modulates telomerase-mediated telomere elongation. It is possible that POT1 also influences DNA synthesis during semiconservative DNA replication, which is initiated by the DNA polymerase alpha-primase complex. The heterotrimeric ss DNA-binding protein RPA plays essential roles during DNA replication. RPA binds to ss DNA with high affinity in order to stabilize ss DNA and facilitate nascent strand synthesis at the replication fork. Here we investigate how the two proteins RPA and POT1 contribute to telomere maintenance by regulating semi-conservative DNA replication and telomerase. Using chromatin immunoprecipitation experiments, we show that RPA associates with telomeres during S-phase. Analysis of telomere structure in cells shRNA-depleted for RPA and POT1 reveals that loss of RPA and POT1 causes exposure of single-stranded DNA at telomeres, suggestive of incomplete DNA replication. Biochemical experiments using purified recombinant POT1 and RPA show that saturating telomeric oligonucleotides with POT1 or RPA reduces the primase activity of the DNA polymerase alpha-primase complex and the overall activity of telomerase. POT1 and RPA also increase the primer extension by DNA polymerase alpha-primase complex and the processivity of telomerase under certain conditions, although POT1 increases the activities to a greater extent than RPA. We propose that POT1 is required for proper replication of the lagging strand of telomeres and that some phenotypes observed in POT1-depleted cells may stern from incomplete DNA replication rather than de-protection of the single-stranded overhang. Résumé Les télomères, les extrémités normales des chromosomes linéaires, doivent être protégés des fusions chromosomiques, d'événements de recombinaison homologue aberrants et de phénomènes de dégradation. Chez l'Homme, les extrémités des chromosomes sont constitués d'ADN double brin répétitif de séquence 5'-TTAGGG-3', d'une extension simple brin 3' sortante et d'un complexe protéique formé des six facteurs TRF1, TRF2, hRap1, TIN2, TPP1 et POT1 qui, s'associant à cette séquence, protègent l'ADN télomèrique. Les télomères sont maintenus par la télomérase, une transcriptase inverse capable d'allonger l'extension 3' sortante télomérique. POT1 lie l'ADN simple brin télomérique et module l'élongation des télomères par la télomérase. POT1 pourrait en théorie également influencer la réplication semi-conservative de l'ADN. L'ADN-polymérase Pal alpha-primase amorce et initie la synthèse d'ADN. Pendant la réplication, l'ADN simple brin est stabilisé par RPA, un complexe hétérotrimèrique qui lie l'ADN simple brin. RPA facilite la synthèse du brin naissant à la fourche de réplication. Ici nous avons étudié comment ces deux protéines qui lient l'ADN simple brin, RPA et POT1, régulent la réplication des télomères par la télomérase et la machinerie classique de réplication de l'ADN. Par immunoprécipitation de chromatine (ChIP), nous montrons que RPA est localisé aux télomères lors de la phase S du cycle cellulaire. De plus, l'analyse de la structure des télomeres indique que !a perte de RPA ou de POT1 conduit à l'apparition d'ADN simple brin télomérique, suggérant une réplication incomplète de l'ADN télomérique in vivo. Par une approche complémentaire biochimique utilisant les protéines POT1 et RPA recombinantes purifiées, nous montrons également que la liaison de POT1 ou de RPA à des oligonucléotides télomériques bloque l'activité primase du complexe polymérase alpha/primase et réduit l'activité télomérase sur ces substrats. En revanche, leur liaison augmente l'activité ADN-polymérase du complexe polymérase alpha/primase, ainsi que fa processivité de la télomérase dans certaines conditions, POT1 étant le plus efficace des deux facteurs. Nous proposons que POT1 est nécessaire à la réplication du brin retardé au niveau des télomères, ce qui suggère que certains phénotypes des cellules déplétés en POT1 puissent résulter d'une réplication incomplète de l'ADN télémétrique plutôt que d'une déprotection de l'extrémité sortante des télomères.
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Acid-sensing ion channels (ASICs) are neuronal Na(+)-conducting channels activated by extracellular acidification. ASICs are involved in pain sensation, expression of fear, and neurodegeneration after ischemic stroke. Functional ASICs are composed of three identical or homologous subunits, whose extracellular part has a handlike structure. Currently, it is unclear how protonation of residues in extracellular domains controls ASIC activity. Knowledge of these mechanisms would allow a rational development of drugs acting on ASICs. Protonation may induce conformational changes that control the position of the channel gate. We used voltage-clamp fluorometry with fluorophores attached to residues in different domains of ASIC1a to detect conformational changes. Comparison of the timing of fluorescence and current signals identified residues involved in movements that preceded desensitization and may therefore be associated with channel opening or early steps leading to desensitization. Other residues participated in movements intimately linked to desensitization and recovery from desensitization. Fluorescence signals of all mutants were detected at more alkaline pH than ionic currents. Their midpoint of pH dependence was close to that of steady-state desensitization, whereas the steepness of the pH fluorescence relationship was closer to that of current activation. A sequence of movements was observed upon acidification, and its backward movements during recovery from desensitization occurred in the reverse order, indicating that the individual steps are interdependent. Furthermore, the fluorescence signal of some labeled residues in the finger domain was strongly quenched by a Trp residue in the neighboring β-ball domain. Upon channel activation, their fluorescence intensity increased, indicating that the finger moved away from the β ball. This extensive analysis of activity-dependent conformational changes in ASICs sheds new light on the mechanisms by which protonation controls ASIC activity.
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While we can’t keep it from blowing, there are ways to influence the wind that carries tons of blowing and drifting snow. Periodically, severe winter storms will create large snow drifts that close roads and driveways, isolate farmsteads and increase snowplowing. Many of these drifting problems happen in the same place year after year. Although there are no foolproof methods of wind and snow control, properly designed and maintained snow fences can reduce or eliminate these problem areas. This publication discusses the benefits of snow fence, then examines the types used by the Iowa Department of Transportation. Finally, it provides information about how you can get involved in the DOT’s Cooperative Snow Fence Program.
Resumo:
A extracção clandestina de areia, nas faixas costeiras e nos leitos das ribeiras, tem sido prática de muitos agregados familiares cabo-verdianos. Nas últimas décadas, a praia de Calhetona (Ilha de Santiago) foi um dos muitos locais que sofreram degradação ambiental significativa, devido à realização desta actividade sem quaisquer planos de extracção e de posterior recuperação das áreas degradadas. Este trabalho, através da conjugação de recolha de dados por inquérito, observação directa e pesquisa documental e bibliográfica, teve como objectivos a caracterização da comunidade (que habita no bairro de Ponta Calhetona) que se dedica à extracção de areia na praia de Calhetona, a descrição da dinâmica da actividade extractiva, a avaliação da percepção que a comunidade tem relativamente às consequências da sua actividade e a descrição do impacte ambiental resultante da extracção de areia. Da análise dos inquéritos, efectuados em Fevereiro de 2012, a 25 chefes de agregados familiares que efectuam a extracção de areia na praia de Calhetona, constata-se que estes são maioritariamente mulheres, predominantemente com idade compreendida entre os 40 e os 59 anos, domésticas, com baixa escolaridade, com famílias numerosas e/ou alargadas a seu cargo e dedicando-se à extração de areia à mais de 10 anos. Os inquiridos, face à situação de vulnerabilidade económica, à falta de emprego e à grande procura de areia para a construção civil, vêem nesta actividade uma fonte de rendimento. Contudo, o proveito obtido desta actividade difícil e potencialmente perigosa é reduzido. Quem efectivamente beneficia são os camionistas que compram a areia a quem procede à extracção e a vendem ao consumidor final pelo dobro do preço. Os inquiridos demonstram uma consciência generalizada dos diversos impactes ambientais negativos resultantes da sua actividade, mas alegam que a extracção de areia é uma das poucas alternativas existentes para providenciar o sustento dos seus agregados familiares. Com base na comparação do estado actual da praia de Calhetona com relatos de habitantes locais, relativos às características da mesma no passado, verifica-se que nos últimos 40-50 anos, desde que se iniciou a intensa extracção de areia nesta praia, o seu aspecto físico se degradou claramente. Essa degradação caracteriza-se principalmente pelo recuo da linha de costa, pela quase ausência de areia e pela salinização dos solos localizados nas proximidades da praia, para além dos consequentes impactes negativos sobre a desova das tartarugas e o turismo balnear.
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Two alloys, Fe80Nb10B10 and Fe70Ni14Zr6B10, were produced by mechanical alloying. The formation of thenanocrystallites (about 7-8 nm at 80h MA) was detected by X-ray diffraction. After milling for 80 h, differentialscanning calorimetry scans show low-temperature recovery processes and several crystallization processes related with crystal growth and reordering of crystalline phases. The apparent activation energy values are 315 ± 40 kJ mol–1 for alloy A, and 295 ± 20 kJ mol–1 and 320 ± 25 kJ mol–1 for alloy B. Furthermore, a melt-spun Fe-based ribbon was mechanically alloyed to obtain a powdered-like alloy. The increase of the rotation speed and the ball-to-powderweight ratio reduces the necessary time to obtain the powdered form
Resumo:
Pyochelin (Pch) and enantio-pyochelin (EPch) are enantiomer siderophores that are produced by Pseudomonas aeruginosa and Pseudomonas fluorescens, respectively, under iron limitation. Pch promotes growth of P. aeruginosa when iron is scarce, and EPch carries out the same biological function in P. fluorescens. However, the two siderophores are unable to promote growth in the heterologous species, indicating that siderophore-mediated iron uptake is highly stereospecific. In the present work, using binding and iron uptake assays, we found that FptA, the Fe-Pch outer membrane transporter of P. aeruginosa, recognized (K(d) = 2.5 +/- 1.1 nm) and transported Fe-Pch but did not interact with Fe-EPch. Likewise, FetA, the Fe-EPch receptor of P. fluorescens, was specific for Fe-EPch (K(d) = 3.7 +/- 2.1 nm) but did not bind and transport Fe-Pch. Growth promotion experiments performed under iron-limiting conditions confirmed that FptA and FetA are highly specific for Pch and EPch, respectively. When fptA and fetA along with adjacent transport genes involved in siderophore uptake were swapped between the two bacterial species, P. aeruginosa became able to utilize Fe-EPch as an iron source, and P. fluorescens was able to grow with Fe-Pch. Docking experiments using the FptA structure and binding assays showed that the stereospecificity of Pch recognition by FptA was mostly due to the configuration of the siderophore chiral centers C4'' and C2'' and was only weakly dependent on the configuration of the C4' carbon atom. Together, these findings increase our understanding of the stereospecific interaction between Pch and its outer membrane receptor FptA.
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This paper provides an explicit cofibrant resolution of the operad encoding Batalin-Vilkovisky algebras. Thus it defines the notion of homotopy Batalin-Vilkovisky algebras with the required homotopy properties. To define this resolution we extend the theory of Koszul duality to operads and properads that are defind by quadratic and linear relations. The operad encoding Batalin-Vilkovisky algebras is shown to be Koszul in this sense. This allows us to prove a Poincare-Birkhoff-Witt Theorem for such an operad and to give an explicit small quasi-free resolution for it. This particular resolution enables us to describe the deformation theory and homotopy theory of BV-algebras and of homotopy BV-algebras. We show that any topological conformal field theory carries a homotopy BV-algebra structure which lifts the BV-algebra structure on homology. The same result is proved for the singular chain complex of the double loop space of a topological space endowed with an action of the circle. We also prove the cyclic Deligne conjecture with this cofibrant resolution of the operad BV. We develop the general obstruction theory for algebras over the Koszul resolution of a properad and apply it to extend a conjecture of Lian-Zuckerman, showing that certain vertex algebras have an explicit homotopy BV-algebra structure.
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Computed Tomography (CT) represents the standard imaging modality for tumor volume delineation for radiotherapy treatment planning of retinoblastoma despite some inherent limitations. CT scan is very useful in providing information on physical density for dose calculation and morphological volumetric information but presents a low sensitivity in assessing the tumor viability. On the other hand, 3D ultrasound (US) allows a highly accurate definition of the tumor volume thanks to its high spatial resolution but it is not currently integrated in the treatment planning but used only for diagnosis and follow-up. Our ultimate goal is an automatic segmentation of gross tumor volume (GTV) in the 3D US, the segmentation of the organs at risk (OAR) in the CT and the registration of both modalities. In this paper, we present some preliminary results in this direction. We present 3D active contour-based segmentation of the eye ball and the lens in CT images; the presented approach incorporates the prior knowledge of the anatomy by using a 3D geometrical eye model. The automated segmentation results are validated by comparing with manual segmentations. Then, we present two approaches for the fusion of 3D CT and US images: (i) landmark-based transformation, and (ii) object-based transformation that makes use of eye ball contour information on CT and US images.
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OBJECTIVES: To evaluate morbidity associated with the radial forearm free flap donor site and to compare functional and aesthetic outcomes of ulnar-based transposition flap (UBTF) vs split-thickness skin graft (STSG) closure of the donor site.¦DESIGN: Case-control study.¦SETTING: Tertiary care institution.¦PATIENTS: The inclusion criteria were flap size not exceeding 30 cm(2), patient availability for a single follow-up visit, and performance of surgery at least 6 months previously. Forty-four patients were included in the study and were reviewed. Twenty-two patients had UBTF closure, and 22 had STSG closure.¦MAIN OUTCOME MEASURES: Variables analyzed included wrist mobility, Michigan Hand Outcomes Questionnaire scores, pinch and grip strength (using a dynamometer), and hand sensitivity (using monofilament testing over the radial nerve distribution). In analyses of operated arms vs nonoperated arms, variables obtained only for the operated arms included Vancouver Scar Scale scores and visual analog scale scores for Aesthetics and Overall Arm Function.¦RESULTS: The mean (SD) wrist extension was significantly better in the UBTF group (56.0° [10.4°] for nonoperated arms and 62.0° [9.7°] for operated arms) than in the STSG group (59.0° [7.1°] for nonoperated arms and 58.4° [12.1°] for operated arms) (P = .02). The improvement in wrist range of motion for the UBTF group approached statistical significance (P = .07). All other variables (Michigan Hand Outcomes Questionnaire scores, pinch and grip strength, hand sensitivity, and visual analog scale scores) were significantly better for nonoperated arms vs operated arms, but no significant differences were observed between the UBTF and STSG groups.¦CONCLUSIONS: The radial forearm free flap donor site carries significant morbidity. Donor site UBTF closure was associated with improved wrist extension and represents an alternative method of closure for small donor site defects.
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The Iowa Leading Indicators Index (ILII) Annual Assessment and Update assesses how well the ILII has met the goals behind its development, gauges the validity of the existing components, considers additional components that have been suggested along the way, and carries out the annual updates necessary for such an index.
Resumo:
The Iowa Leading Indicators Index (ILII) Annual Assessment and Update assesses how well the ILII has met the goals behind its development, gauges the validity of the existing components, considers additional components that have been suggested along the way, and carries out the annual updates necessary for such an index.
Resumo:
The Iowa Leading Indicators Index (ILII) Annual Assessment and Update assesses how well the ILII has met the goals behind its development, gauges the validity of the existing components, considers additional components that have been suggested along the way, and carries out the annual updates necessary for such an index.
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Els jocs són una de les indústries de software més gran del món de la informàtica. Des dels primers jocs en blanc i negre que simulaven raquetes i una pilota, fins avui en dia, en que el desenvolupament d’un joc porta darrere un equip de professionals tant o més gran que el major dels projectes informàtics del món de les indústries, els jocs han evolucionat més que la majoria de programes. La possibilitat d’elaborar un joc és, a part d’una proposta temptadora (ja que difereix enormement de qualsevol pràctica feta durant la carrera), un repte de caire personal per algú que sempre ha estat en contacte amb videojocs i que, després d’adquirir una sèrie de coneixements indispensables, s’ha proposat d’intentar desenvolupar-ne un des de l’arrel. L’objectiu d’aquest treball és doncs això, aprendre com neix un joc partint de res, i veure totes les complicacions que sorgeixen a l’hora de desenvolupar-lo. Els resultats delt projecte mostren generosament el gran nombre de problemes que sorgeixen en un procés com aquest, però com a conclusions importants cal destacar la satisfacció envers els resultats obtinguts, així com els coneixements que s’han guanyat mitjançant el desenvolupament del programa.
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The attraction of walking as a pastime has grown enormously in Switzerland over the past few years. Synonym of health and wellbeing, this activity carries some risks which more and more patients are questioning; answering these questions is not always obvious, so we wanted to tackle the subject. This second section concerns risks linked to food which can be found in the forest. Echinococcosis is an underestimated parasite which affects a large proportion of foxes in Switzerland. This infectious disease can also affect man following contamination which usually occurs through eating berries. Prevention is the most effective way to avoid poisoning by mushrooms. In case of poisoning, the physician must try and determine the toxidrome. The key element is the length of time before symptoms develop. Treatment is always symptomatic, using activated charcoal.