6,613 research outputs found
Dismantling Lamarckism: why descriptions of socio-economic evolution as Lamarckian are misleading
“The original publication is available at www.springerlink.com”. Copyright Springer.This paper addresses the widespread tendency to describe socio-economic evolution as Lamarckian. The difference between Lamarckian and Darwinian replication is clarified. It is shown that a phenotype-genotype distinction must first be established before we can identify Lamarckian transmission. To qualify as Lamarckian inheritance, acquired properties at the phenotypic level must be encoded in a genotype that is passed on to the next generation. Some possible social replicators (or genotypes) are identified, with a view to exploring possible distinctions between genotype and phenotype at the social level. It is concluded that the Lamarckian label does not readily transfer to socio-economic evolution, despite the fact that social genotypes (such as routines) may adapt within any given phenotype (such as an organisation). By contrast, no such problems exist with the description of socio-economic evolution as Darwinian.Peer reviewe
Computer program developed for flowsheet calculations and process data reduction
Computer program PACER-65, is used for flowsheet calculations and easily adapted to process data reduction. Each unit, vessel, meter, and processing operation in the overall flowsheet is represented by a separate subroutine, which the program calls in the order required to complete an overall flowsheet calculation
Physical properties and morphology of a newly identified compact z=4.04 lensed submillimeter galaxy in Abell 2218
We present the identification of a bright submm source, SMMJ163555.5+661300,
detected in the lensing cluster Abell2218, for which we have accurately
determined the position using observations from the Submillimeter Array (SMA).
The identified optical counterpart has a spectroscopic redshift of
z=4.044+-0.001 if we attribute the single emission line detected at
lambda=6140AA to Lyman-alpha. This redshift identification is in good agreement
with the optical/near-infrared photometric redshift as well as the submm flux
ratio S_450/S_850~1.6, the radio-submm flux ratio S_1.4/S_850 < 0.004, and the
24um to 850um flux ratio S_24/S_850 < 0.005. Correcting for the gravitational
lensing amplification of ~5.5, we find that the source has a far-infrared
luminosity of 1.3x10^12 Lsun, which implies a star formation rate of 230
Msun/yr. This makes it the lowest-luminosity SMG known at z>4 to date. Previous
CO(4-3) emission line obserations yielded a non-detection, for which we derived
an upper limit of the CO line luminosity of L'_CO = 0.3x10^10 K km/s/pc^2,
which is not inconsistent with the L'_CO - L_FIR relation for starburst
galaxies. The best fit model to the optical and near-infrared photometry give a
stellar population with an age of 1.4 Gyr and a stellar mass of 1.6x10^10 Msun.
The optical morphology is compact and in the source plane the galaxy has an
extent of ~6kpc x 3kpc with individual star forming knots of <500 pc in size.
J163556 is not resolved in the SMA data and we place a strict upper limit on
the size of the starburst region of 8kpc x 3kpc, which implies a lower limit on
the star formation rate surface density of 12 Msun/yr/kpc^2. The redshift of
J163556 extends the redshift distribution of faint, lensed SMGs, and we find no
evidence that these have a different redshift distribution than bright SMGs.Comment: Accepted for publication in ApJ. 11 pages, 7 figure
Vertex Fault Tolerant Additive Spanners
A {\em fault-tolerant} structure for a network is required to continue
functioning following the failure of some of the network's edges or vertices.
In this paper, we address the problem of designing a {\em fault-tolerant}
additive spanner, namely, a subgraph of the network such that
subsequent to the failure of a single vertex, the surviving part of still
contains an \emph{additive} spanner for (the surviving part of) , satisfying
for every
. Recently, the problem of constructing fault-tolerant additive
spanners resilient to the failure of up to \emph{edges} has been considered
by Braunschvig et. al. The problem of handling \emph{vertex} failures was left
open therein. In this paper we develop new techniques for constructing additive
FT-spanners overcoming the failure of a single vertex in the graph. Our first
result is an FT-spanner with additive stretch and
edges. Our second result is an FT-spanner with additive stretch and
edges. The construction algorithm consists of two main
components: (a) constructing an FT-clustering graph and (b) applying a modified
path-buying procedure suitably adopted to failure prone settings. Finally, we
also describe two constructions for {\em fault-tolerant multi-source additive
spanners}, aiming to guarantee a bounded additive stretch following a vertex
failure, for every pair of vertices in for a given subset of
sources . The additive stretch bounds of our constructions are 4
and 8 (using a different number of edges)
Development of Spatial Preferences for Counting and Picture Naming
The direction of object enumeration reflects children’s enculturation but previous work on the development of such spatial preferences has been inconsistent. Therefore, we documented directional preferences in finger counting, object counting, and picture naming for children (4 groups from 3 to 6 years, N = 104) and adults (N = 56). We found a right-side preference for finger counting in 3- to 6-year-olds and a left-side preference for counting objects and naming pictures by 6 years of age. Children were consistent in their special preferences when comparing object counting and picture naming, but not in other task pairings. Finally, spatial preferences were not related to cardinality comprehension. These results, together with other recent work, suggest a gradual development of spatial-numerical associations from early non-directional mappings into culturally constrained directional mappings
Origin and significance of 'dispersed facies' basal ice: Svínafellsjökull, Iceland
Dispersed facies basal ice - massive (i.e. structureless) ice with dispersed debris aggregates - is present at the margins of many glaciers and, as a product of internal glacial processes, has the potential to provide important information about the mechanisms of glacier flow and the nature of the subglacial environment. The origin of dispersed facies is poorly understood, with several hypotheses having been advanced for its formation, and there is disagreement as to whether it is largely a sedimentary or a tectonic feature. We test these established hypotheses at the temperate glacier Svfnafellsjokull, Iceland, and find that none fully account for dispersed facies characteristics at this location. Instead, dispersed facies physical, sedimentological and stable-isotope (5180, 8D) characteristics favour a predominantly tectonic origin that we suggest comprises the regelation and straininduced metamorphism of debris-rich basal ice that has been entrained into an englacial position by tectonic processes operating at the base of an icefall. Further thickening of the resultant dispersed facies may also occur tectonically as a result of ice flow against the reverse bed slope of a terminal overdeepening. Lack of efficient subglacial drainage in the region of the overdeepening may limit basal melting and thus favour basal ice preservation, including the preservation of dispersed facies. Despite the relatively low sediment content of dispersed facies (~1.6% by volume), its thickness (up to 25 m) and ubiquity at Svfnafellsjokull results in a significant contribution to annual sediment discharge (1635-3270 m3 a"1) that is ~6.5 times that contributed by debris-rich stratified facies basal ice
Miniature photonic-crystal hydrophone optimized for ocean acoustics
This work reports on an optical hydrophone that is insensitive to hydrostatic
pressure, yet capable of measuring acoustic pressures as low as the background
noise in the ocean in a frequency range of 1 Hz to 100 kHz. The miniature
hydrophone consists of a Fabry-Perot interferometer made of a photonic-crystal
reflector interrogated with a single-mode fiber, and is compatible with
existing fiber-optic technologies. Three sensors with different acoustic power
ranges placed within a sub-wavelength sized hydrophone head allow a high
dynamic range in the excess of 160 dB with a low harmonic distortion of better
than -30 dB. A method for suppressing cross coupling between sensors in the
same hydrophone head is also proposed. A prototype was fabricated, assembled,
and tested. The sensitivity was measured from 100 Hz to 100 kHz, demonstrating
a minimum detectable pressure down to 12 {\mu}Pa (1-Hz noise bandwidth), a
flatband wider than 10 kHz, and very low distortion
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