6,559 research outputs found
Performance Practice in the Music of Steve Reich, by Russell Hartenberger
No full textPwyll ap Siôn discusses Russell Hartenberger\u27s 2016 work.
Hartenberger, Russell. Performance Practice in the Music of Steve Reich. Cambridge: Cambridge University Press, 2016. ISBN 978-1-107-15150-5
Recruitment of AP-1 clathrin adaptors to liposomal membranes
No full textProtein and membrane traffic between organelles within the endocytic and exocytic pathway is mediated most prominently by coated vesicles. These vesicles are formed by the assembly of cytosolic coat proteins onto the donor membrane, which deform it into a bud so that vesicles can pinch off. Clathrin with its associated adaptors, COPI and COPII are the three major coats. Various in vitro studies allowed insight into the mechanism of coat formation. COPI and COPII vesicle budding from chemically defined liposomes has been reconstituted in vitro, using pure coat compounds. Further, it has been demonstrated that cargo is sorted into these vesicles. The mechanism of clathrin-coated vesicle formation appears to be more complicated. The AP-1 clathrin adaptor is involved in vesicle formation at the transGolgi network and endosomes. This work presents an in vitro assay where AP-1 is recruited to peptidoliposomes, presenting covalently linked peptides corresponding to sorting signals. In this system, AP-1 recruitment depends on myristyolated ADP-ribosylation factor(ARF1), GTP or GMP-PNP, tyrosine signals and a small amount of phosphoinositides, most prominently phosphatidyl inositol 4,5bisphosphate. In such a minimal system AP-1 is recruited as a highmolecular weight complex indicating the formation of a precoat in the absence of clathrin. GTP hydrolysis, induced by ARF GTPase-activating protein(ARFGAP1), disassembled this complex. Further, AP-1 is able to enhance the GAP activity of ARFGAP1 on myristoylated ARF1, suggesting a regulatory function of GTP hydrolysis in early steps of coat recruitment. This work provides insights into the mechanism of AP-1 clathrin coat formation which might also be used to investigate the recruitment of other coats
Paul Russell, éd. Vita Griffini Filii Conani. The Medieval Latin Life of Gruffudd ap Cynan. Cardiff, University of Wales Press, 2005
No full textLambert Pierre-Yves. Paul Russell, éd. Vita Griffini Filii Conani. The Medieval Latin Life of Gruffudd ap Cynan. Cardiff, University of Wales Press, 2005. In: Etudes Celtiques, vol. 37, 2011. pp. 222-223
Paul Russell, éd. Vita Griffini Filii Conani. The Medieval Latin Life of Gruffudd ap Cynan. Cardiff, University of Wales Press, 2005
No full textLambert Pierre-Yves. Paul Russell, éd. Vita Griffini Filii Conani. The Medieval Latin Life of Gruffudd ap Cynan. Cardiff, University of Wales Press, 2005. In: Etudes Celtiques, vol. 37, 2011. pp. 222-223
Strongly magnetic Ap stars in the
No full textContext. Knowing the distribution of strongly magnetic Ap stars in the Hertzsprung-Russell diagram (HRD) allows us to study the evolution of their magnetic fields across the main sequence (MS). With a newly extended Ap star sample from APOGEE and available Gaia DR2 data, we can now critically review the results of previous studies based on HIPPARCO
The Treatment of Ties in AP Correlation
No full textThe Kendall tau and AP correlation coefficients are very commonly use to compare two rankings over the same set of items. Even though Kendall tau was originally defined assuming that there are no ties in the rankings, two alternative versions were soon developed to account for ties in two different scenarios: measure the accuracy of an observer with respect to a true and objective ranking, and measure the agreement between two observers in the absence of a true ranking. These two variants prove useful in cases where ties are possible in either ranking, and may indeed result in very different scores. AP correlation was devised to incorporate a top-heaviness component into Kendall tau, penalizing more heavily if differences occur between items at the top of the rankings, making it a very compelling coefficient in Information Retrieval settings. However, the treatment of ties in AP correlation remains an open problem. In this paper we fill this gap, providing closed analytical formulations of AP correlation under the two scenarios of ties contemplated in Kendall tau. In addition,we developed an R package that implements these coefficients.Best Short Paper Accepted author manuscriptMultimedia ComputingWeb Information System
The role of AP-1 proteins in the transforming growth factor-beta signaling pathway in prostate cancer, 2005
No full textTransforming growth factor-beta (TGF-?) has a variety of roles including cell growth inhibition, stimulation of proliferation, differentiation, apoptosis and extracellular matrix (ECM) formation. TGF-? inhibits growth of the epithelial cells in the prostate gland. The ability of TGF-? to inhibit cell growth enables it to act as a potent tumor suppressor. Here, we show that TGF-? has different effects on proliferation in DU145 (TGF-?- responsive) and PC3M (TGF-? - resistant) prostate cancer cell lines. RT-PCR analysis and Real-time PCR data have determined the varying levels of AP-1 family members in both cell lines. In PC3M and DU145 cells, we have shown that TGF-p exerts opposite effects on JunD, cFos and Fra2 expression, suggesting that AP-1 family members may be involved in the differential effects of TGF-? in these cell lines. The present observation confirms an intact inhibitory role of TGF-? on proliferation in DU145 cells, and shows a non-inhibitory function in PC3M cell growth. In PC3M cells TGF-? may exert effects leading to the metastatic nature of this cell line
Nonconvex Notions of Regularity and Convergence of Fundamental Algorithms for Feasibility Problems
No full textWe consider projection algorithms for solving (nonconvex) feasibility problems in Euclidean spaces. Of special interest are the method of alternating projections (AP) and the Douglas--Rachford algorithm (DR). In the case of convex feasibility, firm nonexpansiveness of projection mappings is a global property that yields global convergence of AP and for consistent problems DR. A notion of local subfirm nonexpansiveness with respect to the intersection is introduced for consistent feasibility problems. This, together with a coercivity condition that relates to the regularity of the collection of sets at points in the intersection, yields local linear convergence of AP for a wide class of nonconvex problems and even local linear convergence of nonconvex instances of the DR algorithm
On the periodic variations of geomagnetic activity indices Ap and ap
No full textInternational audienceYearly averages of geomagnetic activity indices Ap for the years 1967?1984 are compared to the respective averages of ?2·Bs, where v is the solar wind velocity and Bs is the southward interplanetary magnetic field (IMF) component. The correlation of both quantities is known to be rather good. Comparing the averages of Ap with ?2 and Bs separately we find that, during the declining phase of the solar cycle, ?2 and during the ascending phase Bs have more influence on Ap. According to this observation (using Fourier spectral analysis) the semiannual and 27 days, Ap variations for the years 1932?1993 were analysed separately for years before and after sunspot minima. Only those time-intervals before sunspot minima with a significant 27-day recurrent period of the IMF sector structure and those intervals after sunspot minima with a significant 28-28.5-day recurrent period of the sector structure were used. The averaged spectra of the two Ap data sets clearly show a period of 27 days before and a period of 28?29 days after sunspot minimum. Moreover, the phase of the average semiannual wave of Ap is significantly different for the two groups of data: the Ap variation maximizes near the equinoxes during the declining phase of the sunspot cycle and near the beginning of April and October during the ascending phase of the sunspot cycle, as predicted by the Russell-McPherron (R-M) mechanism. Analysing the daily variation of ap in an analogue manner, the same equinoctial and R-M mechanisms are seen, suggesting that during phases of the solar cycle, when ap depends more on the IMF-Bs component, the R-M mechanism is predominant, whereas during phases when ap increases as v increases the equinoctial mechanism is more likely to be effective
Delamination Analysis of A Class of AP-PLY Composite Laminates
No full textA recently developed fiber placement architecture, AP-PLY, has been shown to give significantly improved damage tolerance characteristics of composite structures. The behavior of delaminations resulting from low speed impact damage is of particular concern. Major attention has been paid to expand current knowledge on the delamination response of simple AP-PLY composite structure and move towards in-depth understanding of the failure mechanisms behind the damage tolerance. This thesis presents the approaches to predict delamination onset and analyze delamination growth, in support of the search of the optimum woven pattern for AP-PLY composite laminates. The recovered interlaminar stress between layers combined with the maximum stress criterion determined the delamination onset of simple AP-PLY composite laminate under out-of-plane loads. 2D finite element models with cohesive elements inserted in the interfaces of woven layers have been built to evaluate the delamination initiation and propagation in the different woven patterns of simple AP-PLY composite beams. The parameters of the woven pattern, such as the woven angle, the number of woven plies, the number of straight filled plies, and the location of the woven patterns in through the thickness direction, were investigated and shown to have a significant effect on delamination creation and growth. An energy method based on beam theory was proposed to analyze the strain energy release rate (SERR) of an existing crack in an AP-PLY beam structure. The developed analytical method was implemented in isotropic materials and the obtained SERR of a crack was validated by reference results and finite element solutions. The general behavior of crack growth on the left or right crack tip was evaluated and basic trends leading to crack propagation on one side of the crack were established. A correction factor was introduced to improve the accuracy of the SERR of a small crack through the numerical calculation. The singularity of crack tip caused by dissimilar materials was investigated and was found that the inclusion of the singularity effect could increase the accuracy for small cracks. It has been shown that the neutral axis needs to be relocated to decouple the bending and membrane behavior of unsymmetrical composite laminates, thus to meet the requirement of minimizing the strain energy of the delaminated beam to calculate the SERR of a delaminated composite beam. The calculated SERR of a crack in a composite beam has been verified by comparing with a finite element model. The woven plies in AP-PLY composite laminate altered the layup and two conventional laminates with different stacking sequences were identified in an AP-PLY composite laminate based on the assumption that the resin areas were ignored. A step by step approach was developed to obtain the SERR of a crack that goes across different materials. The analytical SERR determined when two materials are used in sequence, sets the stage for optimization of AP-PLY composite laminates without taking account of the effect of the resin area. The procedure of optimization of simple AP-PLY pattern was proposed and industry may benefit for many applications. An equivalent stiffness approach was used to model regions containing resin pockets and straight or inclined composite layers. A series of three point bending tests was carried out where the failure process and loading capacity were evaluated. The methodology, procedure of optimization, philosophy outlined in this thesis might also be applied to the more complicated fully woven AP-PLY composite laminates. The work in this thesis contributes to the understanding of the behavior of AP-PLY composite laminates with delaminations
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