Insulation accelerates rate of cooling with cryogenic fluid

Thermal insulating material increases the rate of heat transfer from the interior of a chamber to a liquid nitrogen-filled metal jacket. A thin film of the material is bonded to the surface of the metal wall facing the liquid nitrogen

Optical Dipole Trapping beyond Rotating Wave Approximation: The case of Large Detuning

We show that the inclusion of counter-rotating terms, usually dropped in evaluations of interaction of an electric dipole of a two level atom with the electromagnetic field, leads to significant modifications of trapping potential in the case of large detuning. The results are shown to be in excellent numerical agreement with recent experimental findings, for the case of modes of Laguerre-Gauss spatial profile.Comment: 13 pages, 2 figure

Revision of the Anastrepha benjamini species group and the A. pallidipennis complex (Diptera: Tephritidae)

The shape of the facial carina in Altastreplia is discussed. Although taxonomically useful, the protrudent form probably occurs by convergence in different species groups. Two species groups in which the carina is usually produced are revised. The belljamini species group includes: belljamini Lima (from southeastern Brazil), gigantea Stone (from Panama), magna, n. sp. (from Colombia and Venezuela), and superj1ua Stone (from Panama). Host data for this group are limited to only one record of benjamilli from a species of Pouteria (Sapotaceae). The pallidipennis complex, which is included in the pseudoparallela species group, is recognized to include: amnis Stone (from southern Brazil and possibly Trinidad), curitis Stone (from Colombia, Peru, and northern Brazil), pallida, n. sp. (from Panama), pallidipennis Greene (from Colombia and Venezuela), and vele::i, n. sp. (from Colombia). These species breed in fruit of Passij10ra (Passifloraceae) (P. ambigua Hems., ligularis Juss., Idtida H.B.K., quadrallgularis L., and seemannii Griseb.). The relationships of these Anastrepliaspecies are discussed, and diagnoses and ill ustrations are provided to permit their identification. A neotype is designated for A. consobrina (Loew), and the identity of this species is clarified.Se discute la forma de la carina de la cara en Anastreplia. Aunque esta caracteristica es util taxonomicamente, probablemente la forma producida ocurre por convergencia en varios grupos de especies. Se revisan dos grupos de especies que normalmente tiene una carina producida. EI grupo benjamini incluye: benjamini Lima (del sureste de Brasil), gigantea Stone (de Panama), magna, sp. n. (de Colombia y Venezuela), y superj1ua Stone (de Panama). Datos de huespedes del grupo belljamini incluyen solo un registro de benjamini en una especie de Pouteria (Sapotaceae). EI complejo pallidipennis, que es una parte del grupo pseudoparallela incluye: amnis Stone (del sur de Brasil y tal vez de Trinidad), curitis Stone (de Colombia, Peru, y el norte de Brasil), pallida, sp. n. (de Panama), pallidipennis Greene (de Colombia y Venezuela), y velezi, sp. n. (de Colombia). Estas cinco especies se alimentan de frutos de Passij10ra (passifloraceae) (P. ambiguaHemsJ., ligularisJuss., nitida H.B.K., quadrangularis L., y seemannii Griseb.). Se discuten las relaciones de estas Anastrepila especies y se proveen diagnoses e ilustraciones para su identificacci6n. Se designa un neotipo de A. consobrina (Loew) , y se establece la identidad de esta especie

The status of Euaresta stelligera (Coquillett) (Diptera: Tephritidae)

Based on examination of morphological characters of specimens from throughout their ranges, Euaresta stelligera (Coquillett) is confirmed to be a distinct species from E. bellula (Snow). The diagnostic characters, distributions, and host plants of both species are discussed. New distribution records for E. aequalis (Loew) and E. tapetis (Coquillett) are also provided, and an error concerning the range of Valentibulla californica is noted

Independence-friendly cylindric set algebras

Independence-friendly logic is a conservative extension of first-order logic that has the same expressive power as existential second-order logic. In her Ph.D. thesis, Dechesne introduces a variant of independence-friendly logic called IFG logic. We attempt to algebraize IFG logic in the same way that Boolean algebra is the algebra of propositional logic and cylindric algebra is the algebra of first-order logic. We define independence-friendly cylindric set algebras and prove two main results. First, every independence-friendly cylindric set algebra over a structure has an underlying Kleene algebra. Moreover, the class of such underlying Kleene algebras generates the variety of all Kleene algebras. Hence the equational theory of the class of Kleene algebras that underly an independence-friendly cylindric set algebra is finitely axiomatizable. Second, every one-dimensional independence-friendly cylindric set algebra over a structure has an underlying monadic Kleene algebra. However, the class of such underlying monadic Kleene algebras does not generate the variety of all monadic Kleene algebras. Finally, we offer a conjecture about which subvariety of monadic Kleene algebras the class of such monadic Kleene algebras does generate.Comment: 42 pages. Submitted to the Logic Journal of the IGPL. See also http://math.colgate.edu/~amann

Surface optical vortices

It is shown how the total internal reflection of orbital-angular-momentum-endowed light can lead to the generation of evanescent light possessing rotational properties in which the intensity distribution is firmly localized in the vicinity of the surface. The characteristics of these surface optical vortices depend on the form of the incident light and on the dielectric mismatch of the two media. The interference of surface optical vortices is shown to give rise to interesting phenomena, including pattern rotation akin to a surface optical Ferris wheel. Applications are envisaged to be in atom lithography, optical surface tweezers, and spanners

Critical issues in library management : organizing for leadership and decision-making

Papers from the thirty-fifth Allerton Institute. [October 24-26, 1993]Includes bibliographical references

Introduction to Occasional Paper no. 198/199

published or submitted for publicatio