889 research outputs found
Gravel pits support waterbird diversity in an urban landscape
We assessed the benefit of 11 gravel pits for the settlement of waterbird communities in an urbanized area lacking natural wetlands. Gravel pits captured 57% of the regional species pool of aquatic birds. We identified 39 species, among which five were regionally rare. We used the Self Organizing Map algorithm to calculate the probabilities of presence of species, and to bring out habitat conditions that predict assemblage patterns. The age of the pits did not correlate with assemblage composition and species richness. There was a positive influence of macrophyte cover on waterbird species richness. Larger pits did not support more species, but species richness increased with connectivity. As alternative wetland habitats, gravel pits are attractive to waterbirds, when they act as stepping stones that ensure connectivity between larger natural and/or artificial wetlands separated in space
Hierarchy Theory of Evolution and the Extended Evolutionary Synthesis: Some Epistemic Bridges, Some Conceptual Rifts
Contemporary evolutionary biology comprises a plural landscape of multiple co-existent conceptual frameworks and strenuous voices that disagree on the nature and scope of evolutionary theory. Since the mid-eighties, some of these conceptual frameworks have denounced the ontologies of the Modern Synthesis and of the updated Standard Theory of Evolution as unfinished or even flawed. In this paper, we analyze and compare two of those conceptual frameworks, namely Niles Eldredge’s Hierarchy Theory of Evolution (with its extended ontology of evolutionary entities) and the Extended Evolutionary Synthesis (with its proposal of an extended ontology of evolutionary processes), in an attempt to map some epistemic bridges (e.g. compatible views of causation; niche construction) and some conceptual rifts (e.g. extra-genetic inheritance; different perspectives on macroevolution; contrasting standpoints held in the “externalism–internalism” debate) that exist between them. This paper seeks to encourage theoretical, philosophical and historiographical discussions about pluralism or the possible unification of contemporary evolutionary biology
The Luminosity Function of Galaxies in SDSS Commissioning Data
During commissioning observations, the Sloan Digital Sky Survey (SDSS) has
produced one of the largest existing galaxy redshift samples selected from CCD
images. Using 11,275 galaxies complete to r^* = 17.6 over 140 square degrees,
we compute the luminosity function of galaxies in the r^* band over a range -23
< M < -16 (for h=1). The result is well-described by a Schechter function with
parameters phi_* = 0.0146 +/- 0.0012 h^3 Mpc^{-3}, M_* = -20.83 +/- 0.03, and
alpha = -1.20 +/- 0.03. The implied luminosity density in r^* is j = (2.6 +/-
0.3) x 10^8 h L_sun Mpc^{-3}. The surface brightness selection threshold has a
negligible impact for M < -18. We measure the luminosity function in the u^*,
g^*, i^*, and z^* bands as well; the slope at low luminosities ranges from
alpha=-1.35 to alpha=-1.2. We measure the bivariate distribution of r^*
luminosity with half-light surface brightness, intrinsic color, and morphology.
High surface brightness, red, highly concentrated galaxies are on average more
luminous than low surface brightness, blue, less concentrated galaxies. If we
synthesize results for R-band or b_j-band using the Petrosian magnitudes with
which the SDSS measures galaxy fluxes, we obtain luminosity densities 2.0 times
that found by the Las Campanas Redshift Survey in R and 1.4 times that found by
the Two-degree Field Galaxy Redshift Survey in b_j. We are able to reproduce
the luminosity functions obtained by these surveys if we also mimic their
isophotal limits for defining galaxy magnitudes, which are shallower and more
redshift dependent than the Petrosian magnitudes used by the SDSS. (Abridged)Comment: 49 pages, including 23 figures, accepted by AJ; some minor textual
changes, plus an important change in comparison to LCR
The compositional and evolutionary logic of metabolism
Metabolism displays striking and robust regularities in the forms of
modularity and hierarchy, whose composition may be compactly described. This
renders metabolic architecture comprehensible as a system, and suggests the
order in which layers of that system emerged. Metabolism also serves as the
foundation in other hierarchies, at least up to cellular integration including
bioenergetics and molecular replication, and trophic ecology. The
recapitulation of patterns first seen in metabolism, in these higher levels,
suggests metabolism as a source of causation or constraint on many forms of
organization in the biosphere.
We identify as modules widely reused subsets of chemicals, reactions, or
functions, each with a conserved internal structure. At the small molecule
substrate level, module boundaries are generally associated with the most
complex reaction mechanisms and the most conserved enzymes. Cofactors form a
structurally and functionally distinctive control layer over the small-molecule
substrate. Complex cofactors are often used at module boundaries of the
substrate level, while simpler ones participate in widely used reactions.
Cofactor functions thus act as "keys" that incorporate classes of organic
reactions within biochemistry.
The same modules that organize the compositional diversity of metabolism are
argued to have governed long-term evolution. Early evolution of core
metabolism, especially carbon-fixation, appears to have required few
innovations among a small number of conserved modules, to produce adaptations
to simple biogeochemical changes of environment. We demonstrate these features
of metabolism at several levels of hierarchy, beginning with the small-molecule
substrate and network architecture, continuing with cofactors and key conserved
reactions, and culminating in the aggregation of multiple diverse physical and
biochemical processes in cells.Comment: 56 pages, 28 figure
From Social Data Mining to Forecasting Socio-Economic Crisis
Socio-economic data mining has a great potential in terms of gaining a better
understanding of problems that our economy and society are facing, such as
financial instability, shortages of resources, or conflicts. Without
large-scale data mining, progress in these areas seems hard or impossible.
Therefore, a suitable, distributed data mining infrastructure and research
centers should be built in Europe. It also appears appropriate to build a
network of Crisis Observatories. They can be imagined as laboratories devoted
to the gathering and processing of enormous volumes of data on both natural
systems such as the Earth and its ecosystem, as well as on human
techno-socio-economic systems, so as to gain early warnings of impending
events. Reality mining provides the chance to adapt more quickly and more
accurately to changing situations. Further opportunities arise by individually
customized services, which however should be provided in a privacy-respecting
way. This requires the development of novel ICT (such as a self- organizing
Web), but most likely new legal regulations and suitable institutions as well.
As long as such regulations are lacking on a world-wide scale, it is in the
public interest that scientists explore what can be done with the huge data
available. Big data do have the potential to change or even threaten democratic
societies. The same applies to sudden and large-scale failures of ICT systems.
Therefore, dealing with data must be done with a large degree of responsibility
and care. Self-interests of individuals, companies or institutions have limits,
where the public interest is affected, and public interest is not a sufficient
justification to violate human rights of individuals. Privacy is a high good,
as confidentiality is, and damaging it would have serious side effects for
society.Comment: 65 pages, 1 figure, Visioneer White Paper, see
http://www.visioneer.ethz.c
Current status of the Spectrograph System for the SuMIRe/PFS
The Prime Focus Spectrograph (PFS) is a new facility instrument for Subaru
Telescope which will be installed in around 2017. It is a multi-object
spectrograph fed by about 2400 fibers placed at the prime focus covering a
hexagonal field-of-view with 1.35 deg diagonals and capable of simultaneously
obtaining data of spectra with wavelengths ranging from 0.38 um to 1.26 um. The
spectrograph system is composed of four identical modules each receiving the
light from 600 fibers. Each module incorporates three channels covering the
wavelength ranges 0.38-0.65 mu ("Blue"), 0.63-0.97 mu ("Red"), and 0.94-1.26 mu
("NIR") respectively; with resolving power which progresses fairly smoothly
from about 2000 in the blue to about 4000 in the infrared. An additional
spectral mode allows reaching a spectral resolution of 5000 at 0.8mu (red). The
proposed optical design is based on a Schmidt collimator facing three Schmidt
cameras (one per spectral channel). This architecture is very robust, well
known and documented. It allows for high image quality with only few simple
elements (high throughput) at the expense of the central obscuration, which
leads to larger optics. Each module has to be modular in its design to allow
for integration and tests and for its safe transport up to the telescope: this
is the main driver for the mechanical design. In particular, each module will
be firstly fully integrated and validated at LAM (France) before it is shipped
to Hawaii. All sub-assemblies will be indexed on the bench to allow for their
accurate repositioning. This paper will give an overview of the spectrograph
system which has successfully passed the Critical Design Review (CDR) in 2014
March and which is now in the construction phase.Comment: 9 pages, 7 figures, submitted to "Ground-based and Airborne
Instrumentation for Astronomy V, Suzanne K. Ramsay, Ian S. McLean, Hideki
Takami, Editors, Proc. SPIE 9147 (2014)
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