215 research outputs found
An introduction to free higher-spin fields (TOPCITE: 130 citazioni su SPIRES HEP)
No full textIn this article we begin by reviewing the (Fang-)Fronsdal construction and the nonlocal
geometric equations with unconstrained gauge fields and parameters built by Francia
and the senior author from the higher-spin curvatures of de Wit and Freedman. We
then turn to the triplet structure of totally symmetric tensors that emerges from free
String Field Theory in the α′ → 0 limit and to its generalization to (A)dS backgrounds,
and conclude with a discussion of a simple local compensator form of the field equations
that displays the unconstrained gauge symmetry of the non-local equations
Adelencyrtus antennatus Compere & Annecke
No full text1. Adelencyrtus antennatus Compere & Annecke (Figs 1−2) Adelencyrtus antennatus Compere & Annecke, 1961: 49. Syntypes (BMNH, examined), South Africa. Adelencyrtus antennatus; Hayat, Alam & Agarwal, 1975: 78; Prinsloo, 1983: 2, 27. Description. Female. Body about 1.3 mm long. Body dark brown with green or blue sheen; antenna brownish-yellow except pedicel and apical 2 / 3 of clava largely brown (Fig. 1); fore wing (Fig. 2) hyaline except for infuscate spot beneath marginal vein and about apical half slightly infuscate; legs yellow except coxae dark brown (sometimes fore coxa yellowish-white and mid tibia brownish subbasally). Head. Frontovertex about 1 / 4 head width; ocelli forming an angle of about 30 º; posterior ocellus touching inner eye margin, and separated from occipital margin by about 4 × its own diameter; antenna (Fig. 1) with scape slightly expanded, about 4 × as long as broad; pedicel about as long as F 1 and F 2 combined; F 1 transverse and the smallest, F 2 −F 6 subquadrate and subequal in size; clava about as long as combined length of F 3 −F 6; mandible quadridentate. Thorax. Fore wing (Fig. 2) about 2.1 × as long as broad; marginal vein long, about 3 × as long as broad; postmarginal vein about half as long as marginal vein; stigmal vein slightly longer than postmarginal vein. Gaster. Ovipositor sheaths slightly exserted, by about 1 / 6 − 1 / 5 gaster length. Relative measurements. MT 55; OL 65; GL 18. Male. Unknown. Host. Aspidiotus sp. (Diaspididae) (Compere & Annecke 1961). Distribution. China (new record), South Africa (Compere & Annecke, 1961). Type material examined. SOUTH AFRICA: Durban, Natal, Dec. 8, 1925, ex. grey Aspidiotus; coll. E.W. Rust (2 ΨΨ syntypes, BMNH). Non-type material examined. CHINA: Yunnan, Xiashuangbanna, 22.vii. 2008, coll. G Zheng (1 Ψ). Comments. The Chinese female agrees with original description of A. antennatus except that all funicular segments except F 1 are slightly longer than broad and the fore coxae are yellow (fore coxae apically yellowish in syntypes). We believe these differences falls within the limits of variation of the species.Published as part of Zhang, Yan-Zhou & Shi, Zhen-Ya, 2010, The species of Adelencyrtus Ashmead and Epitetracnemus Girault (Hymenoptera: Encyrtidae) from China, pp. 1-26 in Zootaxa 2605 on page 3, DOI: 10.5281/zenodo.19766
Liouville theory beyond the cosmological horizon
No full textAbstract: The dS/CFT correspondence postulates the existence of a Euclidean CFT dual to a suitable gravity theory with Dirichlet boundary conditions asymptotic to de Sitter spacetime. A semi-classical model of such a correspondence consists of Einstein gravity with positive cosmological constant and without matter which is dual to Euclidean Liouville theory defined at the future conformal boundary. Here we show that Euclidean Liouville theory is also dual to Einstein gravity with Dirichlet boundary conditions on a fixed timelike slice in the static patch. Intriguingly, the spacetime interpretation of Euclidean Liouville time is the physical time of the static observer. As a prerequisite of this correspondence, we show that the asymptotic symmetry algebra which consists of two copies of the Virasoro algebra extends everywhere into the bulk.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Cryo-Laboratories for Test and Development of Propellant Storage and Management Technologies
No full textThe paper gives an overview on the test possibilities of the Cryogenic Laboratories in BREMEN and TRAUEN of the DLR Institute of Space Systems with regard to the research and development of propellant management and storage technologies for successful future launcher and advanced cryogenic upper stage systems. To satisfy the current and future need for testing and research, different test facilities have been built up and are available in the labs. In particular a hexapod system and a cryogenic tank demonstrator, provided by Astrium ST, are useable for testing. The test possibilities of the cryogenic laboratories and the available test facilities will be presented
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Simulation of engineering systems described by high-index DAE and discontinuous ODE using single step methods
No full texttextThis dissertation presents numerical methods for solving two classes of ordinary
diferential equations (ODE) based on single-step integration methods.
The first class of equations addressed describes the mechanical dynamics
of constrained multibody systems. These equations are ordinary differential
equations (ODE) subject to algebraic constraints. Accordinly they are called
differential-algebraic equations (DAE).
Specific contributions made in this area include an explicit transformation
between the Hessenberg index-3 form for constrained mechanical systems
to a canonical state-space form used in the nonlinear control communities. A
hybrid solution method was developed that incorporates both sliding-mode
control (SMC) from the controls literature and post-stabilization from the
DAE related literature. The process of developing the hybrid method provi
duced insights into both areas in a way that allowed both areas to benefit
from the other’s strengths. First, the hybrid method produced an accurate
and efficient method for simulating sliding-mode control systems. A technique
called post-stabilization provides a more efficient method for simulating SMC
systems than conventional methods using the discontinuous control term. Second,
use of SMC mathematical framework allows the hybrid method to handle
arbitrary, or inconsistent initial conditions.
The second class of equations addressed here are discontinuous ODE.
Specific contributions made in solving DODE include further classification of
discontinnuities into parametric or structural discontinuities as well as unilateral
or bilateral events. Consistent event location and discontinuity sticking
from Park and Barton[56] originally addressed bilateral events only and were
implemented in a single-step environment and then extended to address unilateral
events as well. An effective detection scheme was developed using
low-order interpolants for detecting most events in the correct order. For rare
cases when the detection scheme fails, a try-catch model was implemented to
deal with two possible failure scenarios. The detection and location methods
successfully handled all events in the correct order for the benchmark problems
solved. Lastly, a region of concurrency was developed that can provide large
efficiency gains for some systems containing multiple closely spaced events.Mechanical Engineerin
Mating behaviour and alternative oviposition sites for male eggs in the heteronomous hyperparasitoid Coccophagus gurneyi Compere (Hymenoptera : Aphelinidae)
No full textThe aphelinid parasitoid Coccophagus gurneyi Compere has unusual sex-related host relationships. Females are diploid and develop internally within mealybugs Pseudococcus calceolariae (Maskell). Males, in contrast, are haploid and hyperparasitic, developing on primary parasitoid larvae within the mealybugs. Furthermore, males have been claimed to be capable of either internal or external development, depending on the precise site of deposition of the haploid egg. This diversity of developmental pathways could indicate the existence of a sibling-species complex. We therefore quantified the mating and ovipositional behaviour of C. gurneyi, for comparison with that of an undescribed sibling species. We also checked whether the females deposit male eggs in alternative sites. The pattern of mating was found to be typical of mating behaviour in Coccophagus spp. and was consistent among all mating pairs, suggesting that the colony comprised one species. Further, the mating behaviour was significantly different from that of the undescribed sibling species. The site of male egg deposition varied and is apparently dictated by two factors; whether the mealybug is parasitised and, if so, the size of the parasitoid it contains. If the mealybugs were unparasitised or if the parasitoids within the mealybugs were small ( 1.05 mm), male eggs were deposited within the parasitoids. These results support the claim of alternate host relationships and developmental pathways within males of C. gurneyi
ANALISIS KANDUNGAN Β-KAROTEN PADA BEBERAPA VARIETAS CABAI MERAH (CAPSICUM ANNUUM) SECARA SPEKTROFOTOMETRI UV-VIS
No full textA have applied of research about content of β-carotene in three quality of cabai namely cabai merah besar (Capsicum annuum L. Var. Abreviata Einger huth), cabai merah keriting (Capsicum annuum L. Var. Longum sendt) and cabai rawit (Capsicum frustescens L). For to Analysis and senelles content β-carotene in cabai. Cabai sample to be extraction in demarcation by acetone. The result of extraction to extract again with petroleum eter and applied safonification with KOH 15%. Qualitative analysis applied with Chromatography method in thin layer using petroleum eter : Benzen (9:1).The result it showing there are spot which same on three samples and β-carotene pure as the compere. While Quantitative analysis with spectrofotometri visible using β-carotene pure as compere showing that the content of β-carotene cabai merah besar 154,32 mg/g, cabai merah keriting 181,41 mg/g and cabai rawit 146,85 mg/g.A have applied of research about content of β-carotene in three quality of cabai namely cabai merah besar (Capsicum annuum L. Var. Abreviata Einger huth), cabai merah keriting (Capsicum annuum L. Var. Longum sendt) and cabai rawit (Capsicum frustescens L). For to Analysis and senelles content β-carotene in cabai. Cabai sample to be extraction in demarcation by acetone. The result of extraction to extract again with petroleum eter and applied safonification with KOH 15%. Qualitative analysis applied with Chromatography method in thin layer using petroleum eter : Benzen (9:1).The result it showing there are spot which same on three samples and β-carotene pure as the compere. While Quantitative analysis with spectrofotometri visible using β-carotene pure as compere showing that the content of β-carotene cabai merah besar 154,32 mg/g, cabai merah keriting 181,41 mg/g and cabai rawit 146,85 mg/g
Arnoul Gréban : Le mystère de la Passion
No full textGréban (Arnoul). Le mystère de la PassionNumérisation effectuée à partir d'un document original.Commencement : « Veni ad liberandum nos, Domine, Deus virtutum. Pour l'offense du premier pere Que encore tout le gendre compere... »Fin : « Rendons graces a Dieu le Pere, Chantans : Te Deum laudamus. Explicit. »Voy. sur ce manuscrit Le Mystère de la Passion d'Arnoul Greban, publié par MM. G. Paris et G. Raynaud (1878) ; désigné par la lettre C.A l'intérieur du premier plat, 10 proverbes, dont le premier est : « Il fault congnoistre avant aimer.
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