Chemotactic Turning Behaviour of Tubularia Spermatozoa

1. The movements of Tubularia spermatozoa in the vicinity of micropipettes filled with extracts of female hydranths, which chemotactically attract the spermatozoa, have been recorded by multiple-flash photomicrography. 2. When a spermatozoon turns in response to a chemotactic stimulus, the flagellum continues to beat, with a highly asymmetrical pattern of bending, during the turn. 3. The magnitude of the turn, particularly the duration of the period of asymmetrical beating, is variable, but each spermatozoon is only able to make turns in one direction, relative to its own body. 4. Most of the behaviour of these spermatozoa may be explained if the turning mechanism is activated when the spermatozoon detects a decreasing concentration of the chemotactant

Parametric study of advanced multistage axial-flow compressors

Axial flow compressor study to increase pressure ratio and reduce overall lengt

Land use/land cover mapping (1:25000) of Taiwan, Republic of China by automated multispectral interpretation of LANDSAT imagery

Three methods were tested for collection of the training sets needed to establish the spectral signatures of the land uses/land covers sought due to the difficulties of retrospective collection of representative ground control data. Computer preprocessing techniques applied to the digital images to improve the final classification results were geometric corrections, spectral band or image ratioing and statistical cleaning of the representative training sets. A minimal level of statistical verification was made based upon the comparisons between the airphoto estimates and the classification results. The verifications provided a further support to the selection of MSS band 5 and 7. It also indicated that the maximum likelihood ratioing technique can achieve more agreeable classification results with the airphoto estimates than the stepwise discriminant analysis

Single-stage experimental evaluation of boundary layer bleed techniques for high lift stator blades. Compressors design

Design and evaluation of stator blades for use in boundary layer bleed techniques in axial flow compresso

Single-stage experimental evaluation of boundary layer blowing techniques for high lift stator blades. 1 - Compressor design

Boundary layer blowing techniques for high lift stator blades in axial flow compressor

Homology of perfect complexes

It is proved that the sum of the Loewy lengths of the homology modules of a finite free complex F over a local ring R is bounded below by a number depending only on R. This result uncovers, in the structure of modules of finite projective dimension, obstructions to realizing R as a closed fiber of some flat local homomorphism. Other applications include, as special cases, uniform proofs of known results on free actions of elementary abelian groups and of tori on finite CW complexes. The arguments use numerical invariants of objects in general triangulated categories, introduced here and called levels. They allow one to track, through changes of triangulated categories, homological invariants like projective dimension, as well as structural invariants like Loewy length. An intermediate result sharpens, with a new proof, the New Intersection Theorem for commutative algebras over fields. Under additional hypotheses on the ring $R$ stronger estimates are proved for Loewy lengths of modules of finite projective dimension.Comment: This version corrects an error in the statement (and proof) of Theorem 7.4 in the published version of the paper [Adv. Math. 223 (2010) 1731--1781]. These changes do not affect any other results or proofs in the paper. A corrigendum has been submitted

Oviposition and Development of Emerald Ash Borer \u3ci\u3e(Agrilus Planipennis)\u3c/i\u3e (Coleoptera: Buprestidae) on Hosts and Potential Hosts in No-Choice Bioassays

Emerald ash borer (Agrilus planipennis Fairmaire) (Coleoptera: Bupres- tidae) is an invasive phloem-feeding pest native to Asia. It was first identified in North America in 2002 and has killed millions of ash (Fraxinus spp.) trees in southeast Michigan and Essex County, Ontario. Since then, additional populations have been discovered across Michigan and in areas of Ohio, Indiana, Illinois, Maryland, Pennsylvania and West Virginia. In Asia, A. planipennis reportedly colonizes other genera, including species of Juglans, Pterocarya and Ulmus. In North America, attacks on non-ash species have not been observed but there is concern about host switching as ash mortality progresses. From 2003 to 2005, we evaluated A. planipennis oviposition and larval development on 4 North American ash species: green ash (F. pennsylvanica Marshall), white ash (F. americana L.), black ash (F. nigra Marshall), blue ash (F. quadrangulata Michaux), and 6 potential alternate hosts including privet (Ligustrum and Forestiera spp.), Japanese tree lilac (Syringa reticulate (Blumb) Hara), American elm (Ulmus americana L.), black walnut (Juglans nigra L.), hickory (Carya ovata (Miller) K. Koch) and hackberry (Celtis occidentalis L.). In no- choice tests using cut branches in cages, female A. planipennis oviposited on all species tested. Larvae on green ash, white ash, black ash, blue ash and privet developed to the second instar before branches desiccated. Larvae attempted to feed on some black walnut, Japanese tree lilac, American elm and hackberry branches but died as first instars. There were no feeding attempts on hickory branches. We also conducted no-choice tests by placing adult A. planipennis in cages that encircled the lower 1 m of the trunk of live green ash, white ash, black walnut and Japanese tree lilac nursery trees. High densities of larvae developed on green ash and white ash nursery trees but there was no evidence of any larval survival, feeding, or development on the Japanese tree lilac or black walnut nursery trees