3,169 research outputs found
Laurel FULKERSON, The Ovidian Heroine as Author. Reading, Writing, and Community in the Heroides.
No full textTordeur Pol. Laurel FULKERSON, The Ovidian Heroine as Author. Reading, Writing, and Community in the Heroides. . In: L'antiquité classique, Tome 76, 2007. p. 332
Laurel FULKERSON, The Ovidian Heroine as Author. Reading, Writing, and Community in the Heroides.
No full textTordeur Pol. Laurel FULKERSON, The Ovidian Heroine as Author. Reading, Writing, and Community in the Heroides. . In: L'antiquité classique, Tome 76, 2007. p. 332
Tony Woodman et Jonathan Powell (Ed.), Author and Audience in Latin Literature
No full textTordeur Pol. Tony Woodman et Jonathan Powell (Ed.), Author and Audience in Latin Literature. In: L'antiquité classique, Tome 63, 1994. pp. 382-383
Critical analysis of strand-biased somatic mutation signatures in TP53 versus Ig genes, in genome-wide data and the etiology of cancer
No full textPrevious analyses of rearranged immunoglobulin (Ig) variable genes (VDJs) concluded that the mechanism of Ig somatic hypermutation (SHM) involves the Ig pre-mRNA acting as a copying template resulting in characteristic strand-biased somatic mutation patterns at A:T and G:C base pairs. We have since analysed cancer genome data and found the same mutation strand-biases, in toto or in part, in nonlymphoid cancers. Here we have analysed somatic mutations in a single well characterised gene TP53. Our goal is to understand the genesis of the strand-biased mutation patterns in TP53 - and in genome-wide data - that may arise by "endogenous" mechanisms as opposed to adduct-generated DNA-targeted strand-biased mutations caused by well characterised "external" carcinogenic influences in cigarette smoke, UV-light and certain dietary components. The underlying strand-biased mutation signatures in TP53, for many nonlymphoid cancers, bear a striking resemblance to the Ig SHM pattern. A similar pattern can be found in genome-wide somatic mutations in cancer genomes that have also mutated TP53. The analysis implies a role for base-modified RNA template intermediates coupled to reverse transcription in the genesis of many cancers. Thus Ig SHM may be inappropriately activated in many non-lymphoid tissues via hormonal and/or inflammation-related processes leading to cancer
Looking back
No full textThese days the Government Architect is an influential consultant, who gets the attention of a number of government ministers. A Government Architect doesnt find much time to do any actual building though, and the same will be true for the new Government Architect, Liesbeth van der Pol, who was appointed in August. A look back at the old-fashioned Government Architects and their predecessors
The synthesis and structural characterisation of novel 4- and 5- membered nitrogen heterocycles derived from azoacetates
No full textAzo-drugs are among the earliest fully synthetic chemotherapeutic agents known (Prontosil 1935).
However the synthesis and application of phenylazo compounds in the area of medicinal chemistry
has largely been restricted to derivatives of primary aromatic amines. This has been due, in the most
part, to a perceived view that azo compounds not containing two aromatic groups are unstable. The
syntheses of a number of novel heterocycles including important medicinal structures directly
linked to an arylazo moiety are reported. The literature survey introduces a range of four and five
membered heterocycles with established pharmaceutical activity. In particular the attention is drawn
to molecules containing the azo functional group. This thesis contains a chapter detailing the
introduction of a variety of alkyl and aryl groups into novel �-lactam molecules bearing the arylazo
and arylazoxy functional groups. The succeeding chapter investigates the role of the azocarbinol
group as an intermediate in the rearrangement of azoacetates to N-acyl hydrazides. The
deacetylation reactions of azoacetates derived from L-threonine are also described. This work
resulted in the synthesis of novel oxazolidinone and hydantoin species, also with phenylazo
attachments. The final chapter describes the incorporation of a cyanide unit into heterocyclic
compounds through intermolecular cyclisations of a range of substituted azoacetates when
potassium cyanide is employed as base. It is shown that the azo group may be incorporated into the
cyclic system to produce pyrazoles, or as an exocyclic pendant group attached to a 2-
iminopyrrolidin-5-one; X-ray crystal structures of these compounds are reported. The 2-
iminopyrrolidin-5-one was easily modified to produce the corresponding pyrrolidine-2,5-dione
(succinimide) derivative. All of the heterocycles reported were generated from azoacetates derived
from simple, cheap and readily available starting materials (ethylacetoacetate and L-threonine), thus
showing azoacetates to be versatile and valuable building blocks in the field of heterocyclic
chemistry
Spatially coherent diffusion of human RNA Pol II depends on transcriptional state rather than chromatin motion
No full textGene transcription by RNA polymerase II (RNAPol II) is a tightly regulated process in the genomic, temporal, and spatial context. Recently, we have shown that chromatin exhibits spatially coherently moving regions over the entire nucleus, which is enhanced by transcription. Yet, it remains unclear how the mobility of RNA Pol II molecules is affected by transcription regulation and whether this response depends on the coordinated chromatin movement. We applied our Dense Flow reConstruction and Correlation method to analyze nucleus-wide coherent movements of RNA Pol II in living human cancer cells. We observe a spatially coherent movement of RNA Pol II molecules over [Image: see text] 1 μm, which depends on transcriptional activity. Inducing transcription in quiescent cells decreased the coherent motion of RNA Pol II. We then quantify the spatial correlation length of RNA Pol II in the context of DNA motion. RNA Pol II and chromatin spatially coherent motions respond oppositely to transcriptional activities. Our study holds the potential of studying the chromatin environment in different nuclear processes
Detecting plume-driven polynyas from dual-pol SAR imagery
No full textAntarctic ocean temperatures are rising due to climate change, causing land ice to melt at increasingly higher rates. Ice shelf bottom melt is a key factor responsible for Antarctic ice mass loss and as such understanding melt processes in the Antarctic is therefore key to more accurately predict how the global sea level will respond to climate change in the foreseeable future. Basal melt results in the formation of both basal melt channels underneath an ice shelf and persistent sea ice wakes (named plume-driven polynyas) at the ice shelf shoreline. The goal of this research is to develop a method that can help to automatically infer basal melt locations along the Antarctic shoreline with significantly increased spatio-temporal resolution compared to previously researched basal melt detection methods.We infer basal melt locations by detecting plume-driven polynyas. We used dual-pol (HH/HV) Sentinel-1 EW SAR data (40x40m resolution) in combination with GLCM textural features as input for a random forest classification that differentiates images as water or ice in four sub-classes: undisturbed ’open’ water, disturbed ’rough’ water, sea ice and (floating) land ice. We assessed what the advantages and limitations of this approach were for plume-driven polynya detection by performing water-ice (sub-class) classifications and examining which GLCM features proved most useful, what GLCM window size is preferred, and how classification can be aided by post-processing classified images.We computed GLCM textures for window sizes w = [5,11,21] and created a classifier for each choice (GLCM5, GLCM11 and GLC21) and compared results to a classifier based on original dual-pol SAR data (BASE). Via cross validated recursive feature elimination we determined that ’sum average’ (HH and HV polarization) and ’difference variance’ (HV polarization) were most useful for separation of water and ice classes (HH_savg, HV_savg and HV_dvar). Our results have shown that using GLCM texture based dual-pol classifiers improves water-ice classification significantly compared to dual-pol only classifiers, although using HH_savg and HV_savg instead of orignal dual-pol data comes at a cost of reduced spatial resolution. Water-ice classification accuracy of BASE was 92.2% (kappa = 84.4%) was increased to 95.9% (kappa = 91.5%) for GLCM5, 96.3% (kappa = 92.7%) for GLCM11 and to 96.5% (kappa = 93.0%) for GLCM21. From a spatial context, GLCM21 showed an insufficient ability to detect small-scaled bodies of water at a sub-kilometer scale. GLCM5 showed unsatisfactory results in terms of sea ice classification. GLCM11 showed highest robustness in both these performance aspects and proved to be most successful classifier for the application of polynya detection. Using an area filter as a post-processing step proved successful when a classifier is based on GLCM data with a window size no larger than w=11. Noise output (small regions of falsely classified open water pixels) was heavily reduced via this form of post-processing and significantly increased polynya detection performance.The final classified product however still contained too many incorrectly classified water regions of similar spatial scales as plume-driven polynyas to be able to apply this algorithm as a reliable automated polynya detection method. We urge to build upon this SAR-based detection method, by using additional non-GLCM input features or using extra post-processing steps, such as temporally filtering water body presence, until results are satisfactory for a fully automated plume-driven polynya detection algorithm. The method presented here has the potential to make detection significantly faster, easier and more accessible than the current methods available. Lastly, in its current state, this method can already be used to validate predicted locations of basal melt by ocean-ice sheet models and DEM-based methods
[[alternative]]On the Critical Path of Van der Pol equation
No full text[[abstract]]在本文中，我們探討范得坡方程式x''+μx'(x^2-1)+x=0在相平面上的一
條特殊軌線 記為y_(∞)(x;μ)，它是范得坡方程式在相平面上的極限
環在某區域中的漸近解。我 們證明在相平面的上半平面中，當μ →
+∞，對於[-1,0]區間中的每個 x，極限環與 y_(∞)(x;μ)的y座標差至
多為O(μ^(-1/3))；更進一步，應用這個結果，可以證明 當μ →
+∞，相平面上每一條從 y 軸出發且在極限環外部的范得坡方程式的軌線
，自 第一次與 x=1 相交於第四象限之後，其與極限環的誤差至多為O(μ
^(-1/3))。
This article is concerned with the special trajectory y_(∞)(x;
μ) which is the leading term of the asymptotic solution
of Van der Pol equation x''+μx'(x^2-1)+x=0 in the phase
plane for some region. We show that in the phase plane,
the difference of this asymptotic solution and the limit
cycle, y_(p)(x), of Van der Pol equation is not greater than
O(μ^(-1/3)) as μ → +∞ for all -1 < x < 0, and use this
result to show that every trajectory of Van der Pol equation
starting from y-axis with initial value bigger than that
of the limit cycle gets close to the limit cycle by O(μ
^(-1/3)) from its first time on for intersecting x=1 in the
fourth quadrant as μ → +∞.
This article is concerned with the special trajectory y_(∞)(x;
Vertebrates At Neotropical Fig Species In A Forest Fragment
No full text[No abstract available]371139141Borges, R.M., Figs. Malabar Giant Squirrels, and fruit shortages within two tropical Indian forests (1993) Biotropica, 25, pp. 183-190Bronstein, J.L., Hoffman, K., Spatial and temporal variation in frugivory at a neotropical fig, Ficus pertusa (1987) Oikos, 49, pp. 261-268De Figueiredo, R.A., Ingestion of Ficus enormis seeds by howler monkeys (Alouatta fusca) in Brazil: Effects on seed germination (1993) Journal of Tropical Ecology, 9, pp. 541-543De Figueiredo, R.A., Complex interactions in the nature: Parrotlet feeding on fig fruits lessens seed dispersal and pollen flow Ciência e Cultura, , in pressDe Figueiredo, R.A., Perin, E., Germination ecology of Ficus luschnathiana drupelets after bird and bat ingestion (1995) Acta Oecologica, 16, pp. 71-75Galetti, M., Diet of the scaly-headed parrot (Pionus maxi-miliani) in a semideciduous forest in southeastern Brazil (1993) Biotropica, 25, pp. 419-425Galetti, M., Pedroni, F., Seasonal diet of capuchin monkeys (Cebus apella) in a semideciduous forest in south-east Brazil (1994) Journal of Tropical Ecology, 10, pp. 27-39Galetti, M., Pedroni, F., Morellato, L.P.C., Diet of the brown howler monkey Alouatta fusca in a forest fragment in southeastern Brazil (1994) Mammalia, 58, pp. 111-118Lambert, F., Fig-eating by birds in a Malaysian lowland rain forest (1989) Journal of Tropical Ecology, 5, pp. 401-412Leighton, M., Leighton, D.R., Vertebrate responses to fruiting seasonality within a Bornean rain forest (1983) Tropical Rain Forest: Ecology and Management, pp. 181-196. , S.L. Sutton, T.C. Whitmore & A.C. Chadwick (eds.) Blackwell Scientific Publications, OxfordMcKey, D., The ecology of coevolved seed dispersal systems (1975) Coevolution of Animals and Plants, pp. 159-191. , L.E. Gilbert & P.M. Haven (eds.) University of Texas Press, AustinPaschoal, M., Galetti, M., Seasonal food use by the neotropical squirrel Sciurus ingrami in southeastern Brazil (1995) Bioiropica, 27, pp. 268-273Patel, A., Hossaert-McKey, M., McKey, D., Ficus-pol-linator research in India: Past, present and future (1993) Current Science, 65, pp. 243-25
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