共查询到20条相似文献,搜索用时 15 毫秒
1.
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: |
2.
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.
相似文献
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: |
7.
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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9.
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: |
10.
T. Ryan Gregory 《Evolution》2008,1(4):358-389
The origin of complex biological structures has long been a subject of interest and debate. Two centuries ago, natural explanations
for their occurrence were considered inconceivable. However, 150 years of scientific investigation have yielded a conceptual
framework, abundant data, and a range of analytical tools capable of addressing this question. This article reviews the various
direct and indirect evolutionary processes that contribute to the origins of complex organs. The evolution of eyes is used
as a case study to illustrate these concepts, and several of the most common misconceptions about complex organ evolution
are discussed.
相似文献
T. Ryan GregoryEmail: |
11.
Heather Rupp Giliah R. Librach Nick C. Feipel Ellen D. Ketterson Dale R. Sengelaub Julia R. Heiman 《Human nature (Hawthorne, N.Y.)》2009,20(1):93-104
Previous research has demonstrated that hormones, relationship goals, and social context influence interest in the opposite
sex. It has not been previously reported, however, whether having a current sexual partner also influences interest in members
of the opposite sex. To test this, we obtained explicit and implicit measures of interest by measuring men’s and women’s subjective
ratings and response times while they evaluated photos of opposite-sex faces. Fifty-nine men and 56 women rated 510 photos
of opposite-sex faces for realism, masculinity, attractiveness, or affect. We found that these subjective ratings were not
influenced by partner status in either men or women. However, women who did not report having a current sexual partner spent
more time evaluating the photos than women who did have partners, demonstrating greater interest in the photos. Sexual partner
status did not predict men’s response times. These findings may reveal that relationship commitment in women suppresses interest
in alternative partners.
相似文献
Heather RuppEmail: |
12.
Coral reef marine protected areas (MPA) are widely distributed around the globe for social and ecological reasons. Relatively
few of these MPAs are well managed. This review examines the governance of coral reef MPAs and the means to improve coral
reef MPA management. It highlights common governance challenges, such as confused goals, conflict, and unrealistic attempts
to scale up beyond institutional capacity. Recommendations, based on field experience and empirical evidence from around the
world, are made for best practices at various stages of MPA implementation.
相似文献
A. T. WhiteEmail: |
13.
Jacob M. Vigil 《Human nature (Hawthorne, N.Y.)》2007,18(2):143-161
Several hypotheses on the form and function of sex differences in social behaviors were tested. The results suggest that friendship
preferences in both sexes can be understood in terms of perceived reciprocity potential—capacity and willingness to engage in a mutually beneficial relationship. Divergent social styles may in turn reflect trade-offs
between behaviors selected to maintain large, functional coalitions in men and intimate, secure relationships in women. The
findings are interpreted from a broad socio-relational framework of the types of behaviors that facilitate selective advertisement
and investment of reciprocity potential across individuals and within groups of men and women.
相似文献
Jacob M. VigilEmail: |
14.
In this paper, we explore the role of reciprocity in the employment of restrictive measures in contexts of contagion. Reciprocity
should be understood as a substantive value that governs the use, level and extent of restrictive measures. We also argue
that independent of the role reciprocity plays in the legitimisation the use of restrictive measures, reciprocity can also
motivate support and compliance with legitimate restrictive measures. The importance of reciprocity has implications for how
restrictive measures should be undertaken when preparing and evaluating public health responses to contagion.
相似文献
A. M. ViensEmail: |
15.
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: |
16.
The integration of multiple predictors promises higher prediction accuracy than the accuracy that can be obtained with a single
predictor. The challenge is how to select the best predictor at any given moment. Traditionally, multiple predictors are run
in parallel and the one that generates the best result is selected for prediction. In this paper, we propose a novel approach
for predictor integration based on the learning of historical predictions. Compared with the traditional approach, it does
not require running all the predictors simultaneously. Instead, it uses classification algorithms such as k-Nearest Neighbor
(k-NN) and Bayesian classification and dimension reduction technique such as Principal Component Analysis (PCA) to forecast the best predictor for the workload under study based on the learning of historical predictions. Then only the
forecasted best predictor is run for prediction. Our experimental results show that it achieved 20.18% higher best predictor
forecasting accuracy than the cumulative MSE based predictor selection approach used in the popular Network Weather Service
system. In addition, it outperformed the observed most accurate single predictor in the pool for 44.23% of the performance
traces.
相似文献
Renato J. FigueiredoEmail: |
17.
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: |
18.
The maintenance of exceptionally high numbers of folk varieties by the Piaroa people of the Venezuelan Amazon is considered.
We cataloged 113 manioc folk varieties, their nomenclature, use and relevant characters, revealing significant insights into
the role of manioc in Piaroa social life. Through a qualitative investigation of the cultivation, processing and symbolic
significance of manioc (Manihot esculenta) in two Piaroa regions over a period of 18 years, we have found that such agrobiodiversity can only be fully explained by
a combination of multiple factors, including pragmatic and ecological considerations, the subtle and complex diversity of
Piaroa manioc preparations and a variety of sociocultural factors, such as manioc’s role as a mediator of social relationships
and as a marker of cultural and social heritage.
相似文献
Stanford ZentEmail: |
19.
Anonymous communications in the Internet 总被引:1,自引:0,他引:1
Arjan Durresi 《Cluster computing》2007,10(1):57-66
With the growth and acceptance of the Internet, there has been increased interest in maintaining anonymity in the network.
By using traffic analysis, it is possible to infer who is talking to whom over the Internet. We present a novel approach to
hide the senders and the receivers of messages. Routes are chosen and frames traverse these routes. Each frame consists of
a token and a node can send a message through a frame only when the corresponding token is free. The advantage of our protocol
is that it poses limited bandwidth overhead when there is at least some traffic, while posing minimal bandwidth overhead when
there is no traffic at all.
相似文献
Arjan DurresiEmail: |
20.
Methanogens growing on C-1 substrates synthesize 2-carbon acetyl groups in the form of acetyl-CoA for carbon assimilation
using the multienzyme complex acetyl-CoA decarbonylase/synthase (ACDS) which contains five different subunits encoded within
an operon. In species growing on acetate ACDS also functions to cleave the acetate C-C bond for energy production by methanogenesis.
A number of species of Methanosarcina that are capable of growth on either C-1 compounds or acetate contain two separate ACDS operons, and questions have been
raised about whether or not these operons play separate roles in acetate synthesis and cleavage. Methanosarcina thermophila genomic DNA was analyzed for the presence of two ACDS operons by PCR amplifications with different primer pairs, restriction
enzyme analyses, DNA sequencing and Southern blot analyses. A single ACDS operon was identified and characterized, with no
evidence for more than one. MALDI mass spectrometric analyses were carried out on ACDS preparations from methanol- and acetate-grown
cells. Peptide fragmentation patterns showed that the same ACDS subunits were present regardless of growth conditions. The
evidence indicates that a single form of ACDS is used both for acetate cleavage during growth on acetate and for acetate synthesis
during growth on C-1 substrates.
Electronic Supplementary Material Supplementary material is available for this article at
相似文献
David A. Grahame (Corresponding author)Email: |
Edward DeMoll (Corresponding author)Email: |