The Role of Boundary Conditions in Solving Finite-Energy, Two-Body, Bound-State Bethe-Salpeter Equations

The difficulties that typically prevent numerical solutions from being obtained to finite-energy, two-body, bound-state Bethe-Salpeter equations can often be overcome by expanding solutions in terms of basis functions that obey the boundary conditions. The method discussed here for solving the Bethe-Salpeter equation requires only that the equation can be Wick rotated and that the two angular variables associated with rotations in three-dimensional space can be separated, properties that are possessed by many Bethe-Salpeter equations including all two-body, bound-state Bethe-Salpeter equations in the ladder approximation. The efficacy of the method is demonstrated by calculating finite-energy solutions to the partially-separated Bethe-Salpeter equation describing the Wick-Cutkosky model when the constituents do not have equal masses.Comment: 18 page

Revealing the History of Sheep Domestication Using Retrovirus Integrations

The domestication of livestock represented a crucial step in human history. By using endogenous retroviruses as genetic markers, we found that sheep differentiated on the basis of their "retrotype" and morphological traits dispersed across Eurasia and Africa via separate migratory episodes. Relicts of the first migrations include the Mouflon, as well as breeds previously recognized as "primitive" on the basis of their morphology, such as the Orkney, Soay, and the Nordic short-tailed sheep now confined to the periphery of northwest Europe. A later migratory episode, involving sheep with improved production traits, shaped the great majority of present-day breeds. The ability to differentiate genetically primitive sheep from more modern breeds provides valuable insights into the history of sheep domestication

Using Virtual Markets to Program Global Behavior in Sensor Networks

This paper presents market-based macroprogramming (MBM), a new paradigm for achieving globally efficient behavior in sensor networks. Rather than programming the individual, low-level behaviors of sensor nodes, MBM defines a virtual market where nodes sell "actions" (such as taking a sensor reading or aggregating data) in response to global price information. Nodes take actions to maximize their own utility, subject to energy budget constraints. The behavior of the network is determined by adjusting the price vectors for each action, rather than by directly specifying local node actions, resulting in a globally efficient allocation of network resources. We present the market-based macro-programming paradigm, as well as several experiments demonstrating its value for a sensor network vehicle tracking application.Engineering and Applied Science

The application of quantitative methods to the study of early development and ovarian structure in mammals

Introduction • I The Pluriovular Follicle, with Reference to its Occurrence in the Ferret • II The Technique of Estimating Small Irregular Areas in Biological Research, with Notes on the Tests of Accuracy • III The Early Development of the Ferret: the Pronuclei • IV The Measurement of Ferret Pronuclei • V The Sizes of Ferret Pronuclei • VI A Quantitative Study of the Polar Body of the Ferret, with a Note on the Second Polar Spindle • VII The Early Development of the Ferret: the Cytoplasm • VIII The Early Development of the Ferret: the Zona Granulosa, Zona Pellucida and Associated Structures • IX The Volumes of Ferret Ova, with Special Reference to the Methods of Determination • X A Study of the Sizes of Nuclei in Ovarian Stroma • Appendix -- Posterior Duplicity in a Dog, with • Reference to Mammalian Teratology in Genera

An Assessment of the Validity of the Developmental Inventory Scales for Children (DISC)

The Developmental Inventory Scales for Children (DISC) was designed as a screening device for preschool children. The purpose of the study was to assess the validity of the DISC. Twenty male and twenty female preschoolers were observed for three 30 minute sessions and their activities recorded by an observer. The observer then rated each child in each of the areas of the DISC under study. Each child was then rated by his/her teacher and one parent using the same rating scales as had the observer. The DISC was then administered to each child and each of the areas under study was scored. Correlations were first completed among the three sources of ratings and were found to be strongly intercorrelated. The DISC scores were then correlated with the three sources of ratings. The DISC correlated significantly with the ratings in only a few instances. It was concluded that the present form of the DISC does not represent a valid screening device. Additional revision of the DISC is necessary, followed by the collection of additional information regarding the reliability and validity of the revised form