Finite domination and Novikov rings. Iterative approach

Suppose C is a bounded chain complex of finitely generated free modules over the Laurent polynomial ring L = R[x,1/x]. Then C is R-finitely dominated, ie, homotopy equivalent over R to a bounded chain complex of finitely generated projective R-modules, if and only if the two chain complexes C((x)) and C((1/x)) are acyclic, as has been proved by Ranicki. Here C((x)) is the tensor product over L of C with the Novikov ring R((x)) = R[[x]][1/x] (also known as the ring of formal Laurent series in x); similarly, C((1/x)) is the tensor product over L of C with the Novikov ring R((1/x)) = R[[1/x]][x]. In this paper, we prove a generalisation of this criterion which allows us to detect finite domination of bounded below chain complexes of projective modules over Laurent rings in several indeterminates.Comment: 15 pages; diagrams typeset with Paul Taylor's "diagrams" macro package. Version 2: clarified proof of main theorem, fixed minor typos; Version 3: expanded introduction, now 16 pages; Version 4: corrected mistake on functoriality of mapping tor

The behavioral response of Notropis artherinoides to a simulated avian predatory attack and the effect of stimulus profile on school density.

Natural History & EvolutionThis study was conducted to determine how schooling characteristics of the emerald shiner, Notropis artherinoides, change in response to the introduction of an avian predatory stimulus. An additional objective was to determine if minnows differentiate between potential predatory threats based on predator profile. Three silhouettes representing a circle, a square, and a cross were flown over a school of 37 shiners. This was repeated three times with varying orders of presentation. Schooling was video-recorded and measured in terms of distance to nearest fish. It was observed that school density was lowest during the introduction of a stimulus, and that there was no significant difference in density between schools observed before and after a stimulus. Furthermore, it was found that distance to nearest fish did not vary with respect to stimulus profile. These findings suggest that emerald shiners do not distinguish potential avian predators based on profile and that passing shadows stimulate a cooperative defensive response.http://deepblue.lib.umich.edu/bitstream/2027.42/88642/1/Quinn_David_2011.pd

When is capital enough to get female microenterprises growing? Evidence from a randomized experiment in Ghana

Standard models of investment predict that credit-constrained firmd should grow rapidly when given additional capital, and that how this capital is provided should not affect decisions to invest in the business or consume the capital. We randomly gave cash and in-kind grants to male- and female- owned microenterprises in urban Ghana. Our findings cast doubt on the ability of caoital alone to stimulate the growth of female microenterprises. First, while the average treatment effects of the in-kind grants are large and positive for both males and females, the gain in profits is almost zerp fpr women with itital profits below the median, suggesting that capital alone is not enough to grow subsistence enterprises owned by women. Second, for women we strongly reject equality of the case and in-kind grants; only in-kind grants lead to growth in business profits. The results for men also suggest a lower impact of cash, but differences between cash and in-kind grants is assoicated more with a lack of self-control than with external pressure. As a result, the manner in which funding is provided affects microenterprise growth.microenterprises; ghana; Conditionality; Asset intergration

GPS compound eye attitude and navigation sensor and method

The present invention is a GPS system for navigation and attitude determination, comprising a sensor array including a convex hemispherical mounting structure having a plurality of mounting surfaces, and a plurality of antennas mounted to the mounting surfaces for receiving signals from space vehicles of a GPS constellation. The present invention also includes a receiver for collecting the signals and making navigation and attitude determinations. In an alternate embodiment the present invention may include two opposing convex hemispherical mounting structures, each of the mounting structures having a plurality of mounting surfaces, and a plurality of antennas mounted to the mounting surfaces

The self-reference effect on memory in early childhood

The self-reference effect in memory is the advantage for information encoded about self, relative to other people. The early development of this effect was explored here using a concrete encoding paradigm. Trials comprised presentation of a self- or other-image paired with a concrete object. In Study 1, 4- to 6-year-old children (N = 53) were asked in each trial whether the child pictured would like the object. Recognition memory showed an advantage for self-paired objects. Study 2 (N = 55) replicated this finding in source memory. In Study 3 (N = 56), participants simply indicated object location. Again, recognition and source memory showed an advantage for self-paired items. These findings are discussed with reference to mechanisms that ensure information of potential self-relevance is reliably encoded