580 research outputs found
Long-term orbital period behaviour of contact binaries V343 Ori and FZ Ori
Get PDF32nd International Physics Congress of Turkish-Physical-Society (TPS) -- SEP 06-09, 2016 -- Bodrum, TURKEYIn this study, we investigated orbital period variations of two contact binaries V343 Ori and FL Ori based on published minima times. Using the O-C analysis, it was found that both systems indicate orbital period increase. Mass transfer from less massive component to more massive component was used to explain increases in the orbital periods. On the other hand, the secular changes in their periods can be a sign of the thermal relaxation oscillation. In the O-C diagram of FL Ori, periodic variations also exist. Cyclic periodic changes can be explained as being the result of a light travel time effect via a tertiary body around the eclipsing pair. The minimum mass of probable tertiary component around FL Ori was found to be 0.63 M-circle dot. In addition, the cyclic variation may be evidence of magnetic activity of the components, which are late-type stars.Turkish Phys So
Ori Apollinis niliaci Hieroglyphica /
No full textWoodcut t.p. border by Hans Holbein, incorporating his initials at left. Froben's device on last p. (Heitz, P. Basler Büchermarken, 30 [Froben's initials there shown are lacking in present work]). Three initials.Caption title.Mode of access: Internet.Five-line inscription on g4r, signed: Dandeus. The name has been written twice more at the foot of g4r (as Dande), and again on g4v (as Dandes).Last leaf (g4) with colophon bound at beginning of Getty copy.Binding: modern marbled paper. Author, title and date on red leather spine label
Factors controlling Hadley circulation changes from the Last Glacial Maximum to the end of the 21st century
Get PDFThe Hadley circulation (HC) extent and strength are analyzed in a wide range of simulated climates from the Last Glacial Maximum to global warming scenarios. Motivated by HC theories, we analyze how the HC is influenced by the subtropical stability, the near-surface meridional potential temperature gradient, and the tropical tropopause level. The subtropical static stability accounts for the bulk of the HC changes across the simulations. However, since it correlates strongly with global mean surface temperature, most HC changes can be attributed to global mean surface temperature changes. The HC widens as the climate warms, and it also weakens, but only robustly so in the Northern Hemisphere. On the other hand, the Southern Hemisphere strength response is uncertain, in part because subtropical static stability changes counteract meridional potential temperature gradient changes to various degrees in different models, with no consensus on the response of the latter to global warming
The discovery of SycO reveals a new function for type three secretion effector chaperones
Get PDFThe Type Three Secretion (T3S) system is a device used by many Gram-negative pathogens that allows bacteria to deliver effector proteins straight into the eukaryotic cell cytosol. These effectors interfere with various signaling pathways to subvert the host cell functions. The secretion machinery of the T3S system consist of a basal body spanning the bacterial inner and outer membrane followed by a stiff hollow needle outside the bacterium. The fully assembled secretion apparatus constitute a continuous hollow conduit that connects the bacteria to the eukaryotic target cell. After cell contact, virulence proteins -called effectors- are injected directly into the cytosol of the host cell via the T3S apparatus. Several effectors of the T3S system require the assistance of specific cytosolic chaperones to be efficiently exported. There are three classes of T3S chaperones. Effector proteins are assisted by Class I chaperones. Although Class I chaperones are well characterized, their main function is still a matter of controversy. In this thesis, we demonstrate that orf155 encodes a specific chaperone for the effector YopO that we called SycO. We showed that SycO enhances YopO secretion in vitro and is required for translocation of YopO into infected cells. By pulldown assay we demonstrated that residues 20 to 77 of YopO are required and sufficient for SycO binding. Using crosslinking experiments and size exclusion chromatography analysis, we determined the stoichiometry of purified SycO and YopO-SycO complexes. SycO alone forms dimers in solution and the YopO-SycO complex has a 1:2 stoichiometry. These results suggested that SycO is a typical chaperone of the Class I. YopO is a serine/theronine kinase that interacts with Rho and Rac and disrupts the cytoskeleton of the target cells. YopO has been shown to localize at the cell plasma-membrane. By transfection of YopO-EGFP hybrid proteins into HEK293T cells, we demonstrated that the chaperone-binding domain (CBD) coincides with the membrane localization domain of YopO. Nevertheless, the CBD was not needed for the kinase activity of YopO. By ultracentrifugation, we also showed that the CBD causes YopO aggregation in the bacteria, when SycO does not cover it. Further, we show that the CBD of YopE and YopT also caused aggregation in the bacteria in the absence of SycE and SycT respectively. YopE, YopT and T3S effectors in other systems also act at the membrane of the eukaryotic host cell. We propose a new hypothesis concerning the role of T3S chaperones. The sub-cellular localization domain of effectors is aggregation-prone and creates the need for a chaperone inside bacteria. We propose that masking such aggregation-prone localization domains may be a general function for type III effector chaperones
Ori-act: Toolbox for urban re-activation
No full textOri-act is a toolbox using the principles of origami and cnc milling in order to provide inhabitants of depreciated neighborhoods in Rotterdam the means to build a physical platform to carry out their initiatives to reactivate their neighborhood.Architecture, Urbanism and Building Sciences | Intectur
Method for flat-foldable curved Miura-ori tessellations
No full textMiniaturizing mechanical tessellations with rigid origami behavior is difficult since rigid origami can only be approached in real mechanical systems. Rigid-origami means that the fold-lines have zero stiffness, and the facets have infinite stiffnes. However, zero stiffness and infinite stiffness can physically not be obtained. To approach the rigid-origami behavior in mechanical tessellation, the stiness of the fold-lines must be reduced. To acquire this low stiness on a micron scale, it is chosen to explore a manufacturing method that uses at material. These at foldable curved tessellations could be used to compensate for the naturally occurring out-of-plane bending of the free edges when at foldable Miura-ori is bend into a cylindrical shell or tube. To compensate for this behavior a legitimate design variation on the Miura-ori pattern has been defined to create a curvature in the folded Miura-ori tessellation. Simulations are used to explore the behavior of the curvature for different parameters of the design variation. Additionally, simulations are performed to explore the behavior of the bend sheet when bend into a Miura-ori tube tessellation. From this simulation the variation indeed showed a curvature for the sheet tessellation and a reduction in curvature of the tube tessellation. To validate if a real mechanical tessellation would show similar curvature in a folded state. A titanium tessellation has been chemically etched and mechanically folded using specialmade mold-stamps. The mechanical titanium sheet tessellations shows a curvature in the folded state, but the curvature is smaller, which is an expected result due to rigid-origami assumptions in the iso-geometric-analysis(IGA) model
The Office of Research Integrity (ORI) perspective on retractions
No full textPresented at the Retractions conference: keeping the pool clean: prevention and management of misconduct related retractions held on July 20-21, 2016 at Hilton Fort Collins in Fort Collins, Colorado.Shara Kabak serves as a Scientist-Investigator in the Division of Investigative Oversight in the Office of Research Integrity (ORI). As a Scientist-Investigator, she responds to allegations of research misconduct and performs oversight of investigations performed at Public Health Service (PHS) funded institutions. Prior to joining ORI, Dr. Kabak was an American Association for the Advancement Science (AAAS) policy fellow at NIH and a member of the Committee on Scientific Conduct and Ethics. She received her Ph.D. in Immunology from the University of Chicago and completed postdoctoral training in the Department of Genetics at the University of Pennsylvania.PowerPoint presentation given on Day 2: Thursday, July 21st, 2016.This conference was funded by the Office of Research Integrity, U.S. Department of Health and Human Services, grant #ORIIR150014
Creating culturally-safe schools for Māori students
No full textIn order to better understand the present trends in New Zealand’s schooling contexts, there is a clarion call for educators to develop sensitivity and sensibility towards the cultural backgrounds and experiences of Māori students. This paper reports on the work of four scholars who share research that has been undertaken in educational settings with high numbers of Māori students, and discusses the importance of creating culturally-safe schools – places that allow and enable students to be who and what they are. The theoretical frameworks drawn on are based on both a life partnership analogy as well as on a socio-cultural perspective on human development and learning. The Māori worldview presented in this paper is connected to the Treaty of Waitangi, The Educultural Wheel and the Hikairo Rationale. Data were collected from two ethnographic case studies and analysed through these frameworks. Practical suggestions are then made for using restorative practices and creating reciprocal relationships in classrooms within an environment of care. The paper reports on an evidence-based approach to creating culturally-safe schools for Māori students
Apsidal motion of two eclipsing binaries: V796 Cyg and V2783 Ori
Get PDF32nd International Physics Congress of Turkish-Physical-Society (TPS) -- SEP 06-09, 2016 -- Bodrum, TURKEYIn this study, the orbital period variations of two eclipsing binary systems showing apsidal motion were studied. Their O - C diagrams were analysed using all reliable eclipse timings and the elements of apsidal motion of two systems were improved. We found periods of apsidal motion of V796 Cyg and V2783 Ori to be 32.7 +/- 0.2 years and 415 +/- 50 years, respectively.Turkish Phys So
Probing the origin of UX Ori-type variability in the YSO binary CO Ori with VLTI/GRAVITY
No full textThis is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordThe primary star in the young stellar object binary CO Ori displays UX Ori-type variability: irregular, high amplitude optical, and near-infrared photometric fluctuations where flux minima coincide with polarization maxima. This is attributed to changes in local opacity. In CO Ori A, these variations exhibit a 12.4 yr cycle. Here, we investigate the physical origin of the fluctuating opacity and its periodicity using interferometric observations of CO Ori obtained using VLTI/GRAVITY. Continuum K-band circum-primary and circum-secondary emission are marginally spatially resolved for the first time, while Brγ emission is detected in the spectrum of the secondary. We estimate a spectral type range for CO Ori B of K2–K5 assuming visual extinction, AV = 2 and a distance of 430 pc. From geometric modelling of the continuum visibilities, the circum-primary emission is consistent with a central point source plus a Gaussian component with a full width at half-maximum of 2.31 ± 0.04 mas, inclined at 30.2° ± 2.2° and with a major axis position angle of 40° ± 6°. This inclination is lower than that reported for the discs of other UX Ori-type stars, providing a first indication that the UX Ori phenomena may arise through fluctuations in circum-stellar material exterior to a disc, for example, in a dusty outflow. An additional wide, symmetric Gaussian component is required to fit the visibilities of CO Ori B, signifying a contribution from scattered light. Finally, closure phases of CO Ori A were used to investigate whether the 12.4 yr periodicity is associated with an undetected third component, as has been previously suggested. We rule out any additional companions contributing more than 3.6 per cent to the K-band flux within ∼7.3–20 mas of CO Ori A.The authors acknowledge support from ERC
Starting Grant “ImagePlanetFormDiscs” (Grant Agreement
No. 639889), Marie Sklodowska-Curie CIG grant (Ref.
618910), Philip Leverhulme Prize (PLP-2013-110), and STFC Rutherford Fellowship (ST/J004030/1).
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