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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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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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In the Indian state of Goa, communally owned agricultural land has persisted through indigenous state rule, colonial occupation
and postcolonial liberation. We show that in Goa, and indeed elsewhere in the world, communally owned land provides protection
against scarcity, risk, and state revenue demands in wet rice agriculture. When wet rice agriculture is the primary agricultural
activity, communally owned land is an effective way to utilize resources. These findings add to the literature that challenges
the inevitability of the tragedy of commonly owned resources.
相似文献
Paul AxelrodEmail: |
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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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Edward Walker Jeffrey P. Gardner Vladimir Litvin Evan L. Turner 《Cluster computing》2007,10(3):339-350
We describe a system for creating personal clusters in user-space to support the submission and management of thousands of
compute-intensive serial jobs to the network-connected compute resources on the NSF TeraGrid. The system implements a robust
infrastructure that submits and manages job proxies across a distributed computing environment. These job proxies contribute
resources to personal clusters created dynamically for a user on-demand. The personal clusters then adapt to the prevailing
job load conditions at the distributed sites by migrating job proxies to sites expected to provide resources more quickly.
Furthermore, the system allows multiple instances of these personal clusters to be created as containers for individual scientific
experiments, allowing the submission environment to be customized for each instance. The version of the system described in
this paper allows users to build large personal Condor and Sun Grid Engine clusters on the TeraGrid. Users then manage their
scientific jobs, within each personal cluster, with a single uniform interface using the feature-rich functionality found
in these job management environments.
相似文献
Evan L. TurnerEmail: |
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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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Douglas Medin Norbert Ross Douglas Cox Scott Atran 《Human ecology: an interdisciplinary journal》2007,35(3):315-329
There is a continuing controversy over Native American fishing and hunting rights. We show that Native American (Menominee)
and European American fish experts have a common knowledge base and share values and attitudes associated with fishing practices
(though organized around different ethical principles). Nonetheless, perceived group differences are dramatic (especially European American perceptions of Native Americans). Cultural differences in models
of nature and associated inference processes appear to mediate these stereotypes and may hold the key to reducing intergroup
conflict over resources.
相似文献
Douglas MedinEmail: |
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Paul Scholte Saïdou Kari Mark Moritz Herbert Prins 《Human ecology: an interdisciplinary journal》2006,34(1):27-51
This paper examines the responses of mobile pastoralists to a floodplain rehabilitation program in north Cameroon. From 1993
to 1999, we measured changes in number of camps and herds, and the time they spent in the 600 km2 of the Logone floodplain that was reflooded in 1994. The first year, few pastoralists anticipated the reflooding or its impact,
and the increase in grazing intensity was caused by a prolonged stay of pastoralists who already used the area for transit.
The following three years showed a sharp increase in the number of camps and herds, which stabilized from 1997 onwards. Overall,
grazing intensity increased threefold, following the gradually recovering perennial grasslands, with no signs of overexploitation
of the area. These developments closely match the ideal preemptive distribution model. We also examined how reflooding affected
pastoral incursions in the Waza National Park located in the floodplain.
相似文献
Paul ScholteEmail: |
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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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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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Rapid prototyping of distributed systems can be achieved by integrating commercial off-the-shelf (COTS) components. With components
as the building blocks, it is important to predict the performance of the system based on the performance of individual components.
In this paper, performance prediction of a system consisting of a small number of components is investigated under different
inter-component communication patterns, and the number of threads provided by components. Based on the experimental results,
it can be inferred that the proposed composition rules provide a reasonably accurate prediction of the performance of a system
made out of these components.
相似文献
Barrett R. BryantEmail: |
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Causal Explanation of Indonesian Forest Fires: Concepts, Applications, and Research Priorities 总被引:1,自引:0,他引:1
Andrew P. Vayda 《Human ecology: an interdisciplinary journal》2006,34(5):615-635
Problems with studies, claims, and assumptions that have been made about the causes of fires in Indonesia's tropical moist forests are identified, and the kinds of concepts, methods, prioritizing, and data needed to resolve the problems are discussed. Separate sections are devoted to studying ignitions, studying fire susceptibility and fire behavior, and using the goal of causal explanation to guide interdisciplinary research.
相似文献
Andrew P. VaydaEmail: |
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B. Oles 《Coral reefs (Online)》2007,26(4):971-981
People have been living on Mwoakilloa, a coral atoll in the Federated States of Micronesia (FSM), for well over a millennium.
Foreign interlopers, colonial governments, global commerce, and a host of internal and external forces have all played a role
in shaping the uses, values, and meanings assigned to the atoll, its reefs, and its resources. This paper explores the changing
relationships among the people and reefs of Mwoakilloa, highlighting the multiple, co-existing, and sometimes competing meanings
and values assigned to atoll resources. It emphasizes the point that even in a small, ethnically homogeneous population there
exists a diversity of meanings associated with reef resources that are dependent upon wider socioeconomic contexts. Identifying
the sources of these cultural meanings is critical for understanding behaviors toward and uses of reef resources, the status
and application of traditional ecological knowledge, and the success and failure of local management measures on Mwoakilloa.
相似文献
B. OlesEmail: |
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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 Palauan archipelago contains one of the most ecologically diverse coral reef systems in the Indo-Pacific that was as attractive
for humans prehistorically as it is today. New evidence is emerging that during the past few thousand years there has been
increasing exploitation of coral reef resources, particularly finfish and mollusks, leading to a decline in taxa numbers,
richness, and diversity in various locales. This paper examines the historical interactions between human populations and
coral reef ecologies in Palau by combining known archaeological data and results from modern biological data of different
reef fauna. The integration of these data sources provides a framework for attempting to explain variations in taxa composition
between islands in the archipelago and how this may relate to human exploitation or other phenomena through time. By using
this perspective to link past events with present-day conditions, we can gain a better sense of the extent to which anthropogenic
changes may have affected island environments in western Micronesia during the Late Holocene. The study also illustrates the
many difficulties researchers face in attempting to synthesize and explain past and present human predation behavior when
using disparate sources of data.
相似文献
S. M. FitzpatrickEmail: |