4,626 research outputs found
Hauser (M.), Burrows (Paul) - The Economies of Unemployment Insurance (avant-propos du Professeur Alan T. Peacock).
No full textMarion Gérald. Hauser (M.), Burrows (Paul) - The Economies of Unemployment Insurance (avant-propos du Professeur Alan T. Peacock).. In: Revue économique, volume 21, n°3, 1970. pp. 492-494
Hauser (M.), Burrows (Paul) - The Economies of Unemployment Insurance (avant-propos du Professeur Alan T. Peacock).
No full textMarion Gérald. Hauser (M.), Burrows (Paul) - The Economies of Unemployment Insurance (avant-propos du Professeur Alan T. Peacock).. In: Revue économique, volume 21, n°3, 1970. pp. 492-494
Synapsid Burrows in the Lower Jurassic Navajo Sandstone, Utah
No full textEnigmatic structures below interdune deposits of the Lower Jurassic Navajo Sandstone near Moab, Utah are interpreted as synapsid burrows based on similar morphologies to fossil and extant synapsid burrows. Two types of burrows are distinguished by their size. Type I burrows are large diameter and comprise complex, high density sinuous tunnels, Y- and T- branched tunnels, sinuous ramps, and chambers. Type I burrows at one locality weather into mounds averaging 33 m x 22 m and extend ~ 1 m above the surface. Type I burrows are dorsoventrally flattened, in cross section averaging 9.3 cm wide and 4.2 cm high, and are sand filled and structureless. These burrows mostly have smooth walls, though some have scalloped walls. Type I burrows represent a new ichnogenera and ichnospecies Labyrinthopolis odieri. These burrows are best explained by multiple individuals living together in social groups similar to modern vole (social) and mole rats (eusocial), and likely represent permanent dwelling structures for foraging, nesting, hiding, and food storage. Type II burrows are mega diameter with simple, inclined tunnels ~ 35 cm wide and ~ 20 cm high, and exhibit well-preserved bilobate morphology along the underside of the tunnel. The walls preserve a series of 3 or 4 thin (~ 4-8 mm), inclined scratch marks from the upper part of the wall and along the floor. Type II burrows represents a new ichnogenera and ichnospecies Schemalitus psalihyponomes. Type II burrows were likely constructed by therapsids based on similarities to therapsid burrows found in South Africa and Antarctica, and likely represents a permanent shelter used for dwelling and brooding. Alternate excavators for Type I and II burrows are rejected by reviewing and comparing burrow morphologies of fossil and extant vertebrate groups because morphologies are consistent within the major groups in both fossil and extant vertebrates. Burrow morphologies reflect the tracemaker's anatomy, social structure, media consistency, and food availability
Earthworm burrows: Kinetics and spatial distribution of enzymes of C-, N- and P- cycles
No full textEarthworms boost microbial activities and consequently create hotspots in soil. Although the presence of earthworms is thought to change the soil enzyme system, the distribution of enzyme activities inside worm burrows is still unknown. For the first time, we analyzed enzyme kinetics and visualized enzyme distribution inside and outside worm burrows (biopores) by in situ soil zymography. Kinetic parameters (V-max and K-m) of 6 enzymes - beta-glucosidase (GLU), cellobiohydrolase (CBH), xylanase (XYL), chitinase (NAG), leucine aminopeptidase (LAP) and acid phosphatase (APT) were determined in pores formed by Lumbricus terrestris L. In earthworm burrows, the spatial distributions of GLU, NAG and APT become observable in zymogram images. Zymography showed a heterogeneous distribution of hotspots in the rhizosphere and worm burrows. The hotspot areas were 2.4-14 times larger in the burrows versus reference soil (soil without earthworms). The significantly higher V-max values for GLU, CBH, XYL, NAG and APT in burrows confirmed that earthworms stimulated enzyme activities. For CBH, XYL and NAG, the 2- to 3-fold higher K-m values in burrows indicated different enzyme systems with lower substrate affinity compared to reference soil. The positive effects of earthworms on V-max were cancelled by the K-m increase for CBH, XYL and NAG at a substrate concentration below 20 mu mol g(-1) soil. The change of enzyme systems reflected a shift in dominant microbial populations toward species with lower affinity to holo-celluloses and to N-acetylglucosamine, and with higher affinity to proteins as compared to the reference soil. We conclude that earthworm burrows are microbial hotspots with much higher and denser distribution of enzyme activities than reference soil. (C) 2016 Elsevier Ltd. All rights reserved
Measurement of disorder in non-periodic sequences
No full textAn information theoretic measure is introduced to compare the disorder in non-periodic sequences. It is shown that the measure correctly distinguishes quasiperiodic and aperiodic sequences which have been deduced from earlier studies using diffraction patterns, although it is often necessary to use a set of measures, depending on the order of the source used. The particular sequences studied are the Thue-Morse sequence and the generalizations of the golden mean sequence commonly studied in connection with quasicrystals.PT: J; CR: ALI MK, 1988, PHYS REV B, V38, P7091 BOMBIERI E, 1986, J PHYS-PARIS, V47, P19 BOMBIERI E, 1987, CONT MATH, V64, P241 BURROWS BL, 1989, INT J MATH ED SCI TE, V20, P913 CHENG Z, 1988, PHYS REV B, V37, P4375 GUMBS G, 1988, J PHYS A, V21, L517 GUMBS G, 1988, PHYS REV LETT, V60, P1081 GUMBS G, 1989, J PHYS A-MATH GEN, V22, P951 HAMMING RW, 1980, CODING INFORMATION T HOLZER M, 1988, PHYS REV B, V38, P1709 HOLZER M, 1988, PHYS REV B, V38, P5756 KOLAR M, 1990, PHYS REV B, V41, P7108 KOLAR M, 1991, PHYS REV B, V43, P1034 MA HR, 1988, J PHYS C SOLID STATE, V21, P4311 MERLIN R, 1985, PHYS REV LETT, V55, P1768 MORSE M, 1921, AM J MATH, V43, P35 MORSE M, 1921, T AM MATH SOC, V22, P84 NIU Q, 1986, PHYS REV LETT, V57, P2057 PENROSE R, 1974, B I MATH APPL, V10, P266 QIN MG, 1990, J PHYS-CONDENS MAT, V2, P1059 RIKLUND R, 1987, INT J MOD PHYS B, V1, P121 SHANNON CE, 1949, MATH THEORY COMMUNIC SHECHTMAN D, 1984, PHYS REV LETT, V53, P1951 THUE A, 1906, NORSKE VID SELSK IMN, V7, P1 THUE A, 1912, NORSKE VID SELSK IMN, V1, P1; NR: 25; TC: 13; J9: J PHYS-A-MATH GEN; PG: 9; GA: GC466Source type: Electronic(1
Many-electron theory of resonant charge transfer: Role of surface states in He and He+ scattering off Si(100)
No full textA many-electron theory of resonant charge transfer, originally formulated for the scattering of an atom with an empty valence orbital from a surface, is extended to treat the case where the valence orbital is initially occupied by one or two electrons. The scattering of He and He+ from the Si(001) surface is investigated. The interaction is assumed to be with the narrow band of surface states, and not the much wider bulk band. As a result, considerable oscillations are found in the ionization and/or neutralization probabilities as a function of the incident energy.PT: J; CR: AMOS AT, 1989, ADV CHEM PHYS, V76, P335 AMOS AT, 1989, SOLID STATE COMMUN, V71, P449 BLOSS W, 1978, SURF SCI, V72, P277 BRAKO R, 1981, SURF SCI, V108, P253 BURROWS BL, 1984, Q APPL MATH, V42, P73 BURROWS BL, 1990, J PHYS A-MATH GEN, V23, P1101 BURROWS BL, 1991, SURF SCI, V253, P365 CHADI DJ, 1975, PHYS STATUS SOLIDI B, V68, P405 HAGSTRUM HD, 1954, PHYS REV, V96, P336 HAGSTRUM HD, 1961, PHYS REV, V122, P83 HERMAN F, 1963, ATOMIC STRUCTURE CAL IHM J, 1980, PHYS REV B, V21, P4592 MUDA Y, 1980, SURF SCI, V97, P283 MUDA Y, 1988, NUCL INSTRUM METH B, V33, P388 MUDA Y, 1988, PHYS REV B, V37, P7048 PAULING L, 1935, INTRO QUANTUM MECHAN ROBERTS N, 1990, SURF SCI, V236, P112 SOUDA R, 1985, SURF SCI, V150, L59 SOUDA R, 1986, NUCL INSTRUM METH B, V15, P114 SOUDA R, 1986, NUCL INSTRUM METH B, V15, P138 SOUDA R, 1986, SURF SCI, V176, P657 SULSTON KW, 1988, PHYS REV B, V37, P9121 SULSTON KW, 1988, SURF SCI, V197, P555 SULSTON KW, 1989, SURF SCI, V244, P543 WEAKLIEM PC, 1990, SURF SCI, V232, L219 WEISENDANGER R, 1990, SURF SCI, V232, P1; NR: 26; TC: 4; J9: PHYS REV B; PG: 11; GA: HZ245Source type: Electronic(1
Yes, they can! Three-banded armadillos Tolypeutes sp. (Cingulata: Dasypodidae) dig their own burrows
No full textIt is believed that the two species of Tolypeutes Illiger, 1811are the only armadillos that do not dig their own burrows, and that these species simply re-use burrows dug by other species. Here, we show that Tolypeutes matacus (Desmarest, 1804) and Tolypeutes tricinctus (Linnaeus, 1758) dig their own burrows. We describe the burrows and three other types of shelters used by them, and provide measurements and frequency of use of the different types of shelter. We have studied free-ranging individuals of T. matacus in two locations in Central Brazil and individuals of T. tricinctus in semi-captivity in the Northeast of Brazil. Individuals of T. matacus were found primarily in small burrows (76%), straw nests (13%), shallow depressions covered with leaf-litter (7%) or in straw nests made on shallow depressions (4%). Adult males and females of T. matacus did not differ in frequency of use of different types of shelter. Sub-adults T. matacus used shallow depressions and nests more often (40%) than adults (22%) and nurslings (10%). Nurslings of T. matacus reused the shelters more frequently (66%), than sub-adults (46%) and adults (35%). Adult females reused burrows and other types of shelter more frequently than adult males. Tolypeutes tricinctus rested mainly in burrows and under leaf-litter, but did not dig depressions or build nests. Tolypeutes tricinctus occasionally used burrows dug by Euphractus sexcinctus (Linnaeus, 1758), but T. matacus never used burrows dug by other species. Nursling T. matacus always shared shelter with an adult female therefore, both used shelters with similar frequency. Adult females and nurslings of T. matacus reused shelters in higher frequency. That can be explained by the fact that adult females with offspring tend to remain for consecutive nights in the same burrow when cubs are recently born. Due to their smaller body size, subadult T. matacus used shelter strategies that require less energetic effort more frequently than adults and nurslings. The habit of covering the burrow entrance with foliage and the burrow?s reduced depth, indicates that Tolypeutes use of burrows is more likely to be related to parental care behavior and thermoregulation strategies than to defense mechanisms. We are confident that the burrows used for resting were indeed dug by Tolypeutes because, besides the direct observation of armadillos digging burrows, the measures of the burrows are very distinctive from those presented as characteristic for the co-occurring burrowing species and are congruent with Tolypeutes size and carapace shape. The newly acquired knowledge that species of Tolypeutes dig burrows can be used to increase the well-being of individuals kept in captivity by adapting enclosures to enable their digging behavior. In addition, this information contributes not only to the study of the ecology and natural history of the species, but can shed new light on the study of the anatomy of specialized diggers. Tolypeutes spp. can comprise the least fossorial of all living armadillo species, but they can no longer be classified as non-diggers
Pseudo-state theory of surface ion neutralization
No full textThe theory of resonant charge transfer is refined to deal with the overlap between the ion orbital and substrate orbitals, to introduce new numerical methods for estimating the interaction and most significantly to construct pseudo-states to model realistic densities of states for substrates.PT: J; CR: ADURU S, 1988, SURF SCI, V205, P269 AMOS AT, 1989, ADV CHEM PHYS, V76, P335 AMOS AT, 1989, SOLID STATE COMMUN, V71, P449 BLOSS W, 1978, SURF SCI, V72, P277 BRAKO R, 1981, SURF SCI, V108, P253 BURROWS BL, 1984, Q APPL MATH, V42, P73 BURROWS BL, 1990, J PHYS A-MATH GEN, V23, P1101 CHADI DJ, 1975, PHYS STATUS SOLIDI B, V68, P405 HERMAN F, 1963, ATOMIC STRUCTURE CAL HOFFMAN AJ, 1953, DUKE MATH J, V20, P37 IHM J, 1980, PHYS REV B, V21, P4592 MUDA Y, 1980, SURF SCI, V97, P283 MUDA Y, 1988, NUCL INSTRUM METH B, V33, P388 MUDA Y, 1988, PHYS REV B, V37, P7048 MURRELL JN, 1985, CHEM BOND SULSTON KW, 1988, CHEM PHYS, V124, P411 SULSTON KW, 1988, PHYS REV B, V37, P9121 SULSTON KW, 1988, SURF SCI, V197, P555 WEAKLIEM PC, 1990, SURF SCI, V232, L219 WEISENDANGER R, 1990, SURF SCI, V232, P1 WILKINSON JH, 1965, ALGEBRAIC EIGENVALUE; NR: 21; TC: 5; J9: SURFACE SCI; PG: 10; GA: GB311Source type: Electronic(1
Marine mammal response to ecosystem variability in Monterey Bay, California
No full textThesis (M.S.) -- San Jose State University, 2009."A thesis presented to the faculty of Moss Landing Marine Laboratories."by Julia Burrows"A thesis presented to the faculty of Moss Landing Marine Laboratories.
A four-stage algorithm for updating a Burrows–Wheeler transform
No full textAbstractWe present a four-stage algorithm that updates the Burrows–Wheeler Transform of a text T, when this text is modified. The Burrows–Wheeler Transform is used by many text compression applications and some self-index data structures. It operates by reordering the letters of a text T to obtain a new text bwt(T) which can be better compressed.Even though recent advances are offering this structure new applications, a major bottleneck still exists: bwt(T) has to be entirely reconstructed from scratch whenever T is modified.We study how standard edit operations (insertion, deletion, substitution of a letter or a factor) that transform a text T into T′ impact bwt(T). Then we present an algorithm that directly converts bwt(T) into bwt(T′). Based on this algorithm, we also sketch a method for converting the suffix array of T into the suffix array of T′.We finally show, based on the experiments we conducted, that this algorithm, whose worst-case time complexity is O(|T|log|T|(1+logσ/loglog|T|)), performs really well in practice and replaces advantageously the traditional approach
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