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1.
Sub-Antarctic Marion Island has had a permanent research station for 50 years and the islands Wandering Albatrosses have been intensively studied for 20 years. The reactions of breeding birds to approaches by a human on foot were recorded. Three response variables were calculated: intensity of vocal reaction (IVR), intensity of non-vocal reaction (INR) and overall response index (ORI). At 5 m from the nest, twice as many birds stood and/or vocalised as at 15 m. Nearest neighbour distance, age and gender did not explain individual variability of responses. Study colony birds had higher IVR scores than non-study colony birds; birds at colonies closest to the station had the highest ORI scores. A better breeding record was associated with lower IVR and ORI scores, but a causative relationship remains to be demonstrated. A minimum viewing distance of 25 m is recommended for breeding Wandering Albatrosses.
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Marienne S. de VilliersEmail: Fax: +27-21-6503434 |
John CooperEmail: |
Peter G. RyanEmail: |
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Terry Harmer 《Cluster computing》2007,10(3):277-285
Gridcast is an R&D project investigating grid ideas and technologies in the broadcasting technical infrastructure. In this
paper I discuss the business and technical issues in building infrastructures to support broadcasters and outline the structure
of the Gridcast grid-based service oriented architecture for broadcasting playout support.
相似文献
Terry HarmerEmail: |
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Roger Sansom 《Biology & philosophy》2008,23(4):475-491
I show that gene regulation networks are qualitatively consistent and therefore sufficiently similar to linearly seperable
connectionist networks to warrant that the connectionist framework be applied to gene regulation. On this view, natural selection
designs gene regulation networks to overcome the difficulty of development. I offer some general lessons about their evolvability
that can be learned by examining the generic features of connectionist networks.
相似文献
Roger SansomEmail: |
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The recent contribution by Jarmila Kukalová-Peck on Hennigian phylogenetics and hexapod limb evolution is critically evaluated.
相似文献
Michael S. Engel (Corresponding author)Email: |
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Peter Godfrey-Smith 《Biology & philosophy》2007,22(3):429-437
Jablonka and Lamb's claim that evolutionary biology is undergoing a ‘revolution’ is queried. But the very concept of revolutionary
change has uncertain application to a field organized in the manner of contemporary biology. The explanatory primacy of sequence
properties is also discussed.
相似文献
Peter Godfrey-SmithEmail: |
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A key point in the analysis of dynamical models of biological systems is to handle systems of relatively high dimensions.
In the present paper we propose a method to hierarchically organize a certain type of piecewise affine (PWA) differential
systems. This specific class of systems has been extensively studied for the past few years, as it provides a good framework
to model gene regulatory networks. The method, shown on several examples, allows a qualitative analysis of the asymptotic
behavior of a PWA system, decomposing it into several smaller subsystems. This technique, based on the well-known strongly
connected components decomposition, is not new. However, its adaptation to the non-smooth PWA differential equations turns
out to be quite relevant because of the strong discrete structure underlying these equations. Its biological relevance is
shown on a 7-dimensional PWA system modeling the gene network responsible for the carbon starvation response in Escherichia coli.
相似文献
Laurent Tournier (Corresponding author)Email: |
Jean-Luc GouzéEmail: |
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Beautrait A Leroux V Chavent M Ghemtio L Devignes MD Smaïl-Tabbone M Cai W Shao X Moreau G Bladon P Yao J Maigret B 《Journal of molecular modeling》2008,14(2):135-148
Numerous methods are available for use as part of a virtual screening strategy but, as yet, no single method is able to guarantee
both a level of confidence comparable to experimental screening and a level of computing efficiency that could drastically
cut the costs of early phase drug discovery campaigns. Here, we present VSM-G (virtual screening manager for computational
grids), a virtual screening platform that combines several structure-based drug design tools. VSM-G aims to be as user-friendly
as possible while retaining enough flexibility to accommodate other in silico techniques as they are developed. In order to
illustrate VSM-G concepts, we present a proof-of-concept study of a fast geometrical matching method based on spherical harmonics
expansions surfaces. This technique is implemented in VSM-G as the first module of a multiple-step sequence tailored for high-throughput
experiments. We show that, using this protocol, notable enrichment of the input molecular database can be achieved against
a specific target, here the liver-X nuclear receptor. The benefits, limitations and applicability of the VSM-G approach are
discussed. Possible improvements of both the geometrical matching technique and its implementation within VSM-G are suggested.
Figure Basic principle of the virtual screening funnel process.
相似文献
Bernard MaigretEmail: |
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Roger Sansom 《Biology & philosophy》2009,24(4):441-459
One current version of the internalism/externalism debate in evolutionary theory focuses on the relative importance of developmental
constraints in evolutionary explanation. The received view of developmental constraints sees them as an internalist concept
that tend to be shared across related species as opposed to selective pressures that are not. Thus, to the extent that constraints
can explain anything, they can better explain similarity across species, while natural selection is better able to explain
their differences. I challenge both of these aspects of the received view and propose a hierarchical view of constraints.
相似文献
Roger SansomEmail: |
14.
Catherine Driscoll 《Biology & philosophy》2008,23(1):101-113
This paper tries to explain how individuals manage adaptive individual choice (i.e., the decision to acquire a fitter than
average behavior or idea rapidly and tractably) in cultural evolution, despite the fact that acquiring fitness information
is very difficult. I argue that the means of solving this problem suggested in the cultural evolution literature largely are
various types of decision rules employing representations of fitness correlated properties or states of affairs. I argue that
the problem of adaptive individual choice is best solved where some of these learning rule representations are socially transmitted
and some are biologically transmitted.
相似文献
Catherine DriscollEmail: |
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Studies on the effects of a variety of exogenous and anthropogenic environmental factors, including endocrine disruptors,
heavy metals, UV light, high temperature, and others, on marine organisms have been presented at the 2nd Bilateral Seminar
Italy–Japan held in November 2006. Reports were discussed in order to reveal the current situation of marine ecosystems, aiming
at evaluation and prediction of environmental risks.
相似文献
V. MatrangaEmail: |
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Strategies of abstraction 总被引:2,自引:1,他引:1
Richard Levins 《Biology & philosophy》2006,21(5):741-755
Abstraction is seen as an active process which both enlightens and obscures. Abstractions are not true or false but relatively
enlightening or obscuring according to the problem under study; different abstractions may grasp different aspects of a problem.
Abstractions may be useless if they can answer questions only about themselves. A theoretical enterprise explores reality
through acluster of abstractions that use different perspectives, temporal and horizontal scales, and assumes different givens.
相似文献
Richard LevinsEmail: |
17.
We develop a formal framework for the optimal allocation of limited resources that includes and clarifies the interplay between
individual optimization and the resulting effects at the population level. As an example, in regard to the evolution of sexual
recombination, the paradox of the twofold cost of sex is avoided by distinguishing between the evolution of recombination
and the subsequent emergence and stability of different mating types as a result of individual optimization within a population
that benefits from recombination.
相似文献
John PepperEmail: |
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Alejandro Rosas 《Biology & philosophy》2008,23(4):555-566
Recent developments in evolutionary game theory argue the superiority of punishment over reciprocity as accounts of large-scale
human cooperation. I introduce a distinction between a behavioral and a psychological perspective on reciprocity and punishment
to question this view. I examine a narrow and a wide version of a psychological mechanism for reciprocity and conclude that a narrow version is clearly distinguishable from punishment, but inadequate for
humans; whereas a wide version is applicable to humans but indistinguishable from punishment. The mechanism for reciprocity
in humans emerges as a meta-norm that governs both retaliation and punishment. I make predictions open to empirical investigation
to confirm or disconfirm this view.
相似文献
Alejandro RosasEmail: |
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Raif Musa-Aziz Lihong Jiang Li-Ming Chen Kevin L. Behar Walter F. Boron 《The Journal of membrane biology》2009,228(1):15-31
Others have shown that exposing oocytes to high levels of (10–20 mM) causes a paradoxical fall in intracellular pH (pHi), whereas low levels (e.g., 0.5 mM) cause little pHi change. Here we monitored pHi and extracellular surface pH (pHS) while exposing oocytes to 5 or 0.5 mM NH3/NH4
+. We confirm that 5 mM causes a paradoxical pHi fall (−ΔpHi ≅ 0.2), but also observe an abrupt pHS fall (−ΔpHS ≅ 0.2)—indicative of NH3 influx—followed by a slow decay. Reducing [NH3/NH4
+] to 0.5 mM minimizes pHi changes but maintains pHS changes at a reduced magnitude. Expressing AmtB (bacterial Rh homologue) exaggerates −ΔpHS at both levels. During removal of 0.5 or 5 mM NH3/NH4
+, failure of pHS to markedly overshoot bulk extracellular pH implies little NH3 efflux and, thus, little free cytosolic NH3/NH4
+. A new analysis of the effects of NH3 vs. NH4
+ fluxes on pHS and pHi indicates that (a) NH3 rather than NH4
+ fluxes dominate pHi and pHS changes and (b) oocytes dispose of most incoming NH3. NMR studies of oocytes exposed to 15N-labeled show no significant formation of glutamine but substantial accumulation in what is likely an acid intracellular compartment. In conclusion, parallel measurements of pHi and pHS demonstrate that NH3 flows across the plasma membrane and provide new insights into how a protein molecule in the plasma membrane—AmtB—enhances
the flux of a gas across a biological membrane.
相似文献
Walter F. Boron (Corresponding author)Email: |
20.
Mark B. Couch 《Biology & philosophy》2009,24(4):505-519
Arguments for multiple realization depend on the idea that the same kind of function is realized by different kinds of structures.
It is important to such arguments that we know the kinds used in the arguments have been individuated properly. In the philosophical
literature, though, claims about how to individuate kinds are frequently decided on intuitive grounds. This paper criticizes
this way of approaching kinds by considering how practicing researchers think about the matter. I will consider several examples
in which the practice of researchers on comparative vision conflicts with the standard account of these issues.
相似文献
Mark B. CouchEmail: |