共查询到20条相似文献,搜索用时 15 毫秒
1.
K. Keahey M. E. Papka Q. Peng D. Schissel G. Abla T. Araki J. Burruss E. Feibush P. Lane S. Klasky T. Leggett D. Mccune L. Randerson 《Cluster computing》2005,8(4):305-311
The National Fusion Collaboratory project seeks to enable fusion scientists to exploit Grid capabilities in support of experimental
science. To this end we are exploring the concept of a collaborative control room that harnesses Grid and collaborative technologies
to provide an environment in which remote experimental devices, codes, and expertise can interact in real time during an experiment.
This concept has the potential to make fusion experiments more efficient by enabling researchers to perform more analysis
and by engaging more expertise from a geographically distributed team of scientists and resources. As the realities of software
development, talent distribution, and budgets increasingly encourage pooling resources and specialization, we see such environments
as a necessary tool for future science.
In this paper, we describe an experimental mock-up of a remote interaction with the DIII-D control room. The collaborative
control room was demonstrated at SC03 and later reviewed at an international ITER Grid Workshop. We describe how the combined
effect of various technologies—collaborative, visualization, and Grid—can be used effectively in experimental science. Specifically,
we describe the Access Grid, experimental data presentation tools, and agreement-based resource management and workflow systems
enabling time-bounded end-to-end application execution. We also report on FusionGrid services whose use during the fusion
experimental cycle became possible for the first time thanks to this technology, and we discuss its potential use in future
fusion experiments. 相似文献
2.
Morange M 《Journal of biosciences》2005,30(3):313-316
The history of science was long considered to be something peripheral to science itself. By supplying interesting stories
and gossip, it seemed, at best, to provide material for enlivening lectures. In general, it was deemed a suitable activity
for retired scientists. This view has been revised considerably in the past years and indeed, today seems hopelessly out of
date. History and philosophy of science are increasingly held to be an essential component of the education of scientists.
By becoming acquainted with these areas, practicing scientists — and in particular biologists — can better appreciate the
significance of the models and theories that underpin their research, especially with the accelerating succession of one idea
by the next. The present series, of which the article that follows is the first, aims to give historical glimpses that bear
on contemporary biology. The hope is that these glimpses will be both a source of inspiration and of help in resisting useless
fashions. 相似文献
3.
In this study, we simulated the process of the evolution of postmating isolation using three models in which postmating isolation
is caused by (1) genetic divergence through collaborative coevolution, (2) genetic divergence through antagonistic coevolution
resulting from sexual conflict, and (3) genetic divergence through combinational incompatibility. The collaborative coevolution
model and the combinational incompatibility model showed a similar decreasing pattern of hybrid compatibility over generations
depending on population size and mutation rates. The antagonistic coevolution model showed that reproductive isolation can
evolve rapidly depending on the intensity of selection. In the combinational incompatibility model, the increasing number
of loci that interact and result in incompatibility would have both promoting and inhibiting effects on the formation of hybrid
incompatibility in the earlier stage of isolation. Mutation rates for genes causing incompatibility significantly affect the
number of generations required for postmating isolation, which indicates that models assuming high mutation rates (e.g., μ = 10−4) might predict much faster evolution for reproductive isolation than those observed in real populations.
Received: January 29, 2001 / Accepted: July 4, 2001 相似文献
4.
V. V. Menshutkin V. F. Levchenko 《Journal of Evolutionary Biochemistry and Physiology》2010,46(6):560-573
Limnology—the science about lakes—is the young and relatively closed area of studies; its existence is owing to several hundreds
of scientists. The International Society of Limnologists holds its meetings since 1922. We used materials of these meetings
to find out the main stages of development of this science; among these stages there were both fast and relatively calm periods.
Based on analysis of these data, we constructed a model of development of the science, the same data being used for tuning
and verification of the model. We have suggested that the main regularities and mechanisms of development of limnology can
be extrapolated to other sciences. The main “acting person” in the model is population of scientists. Each scientist, with
some probability, can propose new ideas as well as use in his studies some particular complex of the already accumulated knowledge
and ideas. The model also takes into consideration how the scientific information is spreading, as well as some individual
peculiarities of model scientists, such as age, experience, communicability. After the model parameters had been chosen in
such a way that is described adequately development of limnology, we performed a series of experiments by changing some of
the characteristics and obtained rather unexpected results published preliminary in the short work (Levchenko, V.F. and Menshutkin,
V.V., Int. J. Comput. Anticip. Syst., 2008, vol. 22, pp. 63–75) and discussed here in the greater detail. It is revealed that development of science occurs irregularly
and is sharply decelerated at low level of communication between scientists and the absence of scientific schools, while the
age of “scientific youth” of scientist usually begins only after 40 years. 相似文献
5.
Seth W. Coleman Zachary W. Culumber Ashley Meaders Jennifer Henson Gil G. Rosenthal 《Environmental Biology of Fishes》2009,86(2):279-284
Ultraviolet radiation—the primary natural pollutant affecting melanomagenesis—may represent a widespread ecological stressor
for many fishes, and yet the relationship between UV-exposure and stress has not been investigated in natural fish populations.
Recent lab-based studies have sought to characterize the relationship between tumorigenesis and the induction of molecular
defenses, such as heat shock proteins. Here we show that ultraviolet radiation and heat shock protein gene expression explain
a significant amount of the variation in hyper-melanization—the phenotypic precursor to melanoma—in wild hybrids of Xiphophorus, laboratory models in cancer research. Our results suggest exposure to UV radiation causes stress which induces molecular
defense mechanisms, which in turn may facilitate tumorigenesis in natural fish populations. Studies of laboratory-based model
organisms in natural settings, like this one, may provide important insights into ecological and evolutionary relationships
obscured in controlled laboratory environments. We hope that ours is only the first of many studies to investigate the such
relationships between environmental stress, stress-induced molecular defenses, and cancer in fishes. 相似文献
6.
Human beings are predisposed to think of evolution as teleological—i.e., having a purpose or directive principle—and the ways
scientists talk about natural selection can feed this predisposition. This work examines the suggestion that students’ teleological
thinking operates as an obstacle when the natural selection evolution model is taught. What we mean by obstacle is an established way of thinking that resists change due to its explanatory power. In light of this approach, the challenges
of teaching evolution in biology education have been revised, and improved methodological strategies aimed at a better comprehension
of the Darwinian evolution model are suggested. 相似文献
7.
Noah Scovronick Stephen Dorey Barbara Häsler Sabine Gabrysch Laura Salonen Silvia Alonso 《EcoHealth》2010,7(2):257-261
Despite an increasing recognition that addressing complex problems requires transdisciplinary research, the shortage of formal
training for how to conduct such research is a major bottleneck to future progress. In response to this training gap, a group
of early career scientists in London created the London EcoHealth Forum. Now in its second year, the Forum has matured into
a small but dedicated group that cultivates thought and learning about ecosystem approaches to health. This paper discusses
the key challenges faced while setting up the group and how they were overcome. The paper also outlines the main activity
of the group, a seminar series devoted to a specific topic—the overconsumption of meat in London—and suggests that this format
may be a useful tool for others who wish to set up a similar organization or teaching program. 相似文献
8.
Charles W. Fowler 《Biodiversity and Conservation》2008,17(4):841-855
Numerous global changes—notably anthropogenic extinction—force reconsideration of our management practices and the ways we
regulate human influence in today’s world. Here, I define management to maximize biodiversity and illustrate the science that
provides information to set goals for such management. Maximizing biodiversity simultaneously achieves sustainability and
systemic health by avoiding the abnormal or pathological. The normal or sustainable are determined through the use of empirical
integrative patterns to objectively account for the complexity of systems within which we find ourselves as a species. The
science that reveals these integrative patterns provides measures of problems that can be solved by maximizing biodiversity—problems
heretofore recognized only qualitatively. I use the Shannon-Weiner information index to test, and, with no surprise, reject
the null hypothesis that there is no direct anthropogenic effect on biodiversity. The results of this science serve as examples
of the kind of information most useful for guiding management and illustrate maximized biodiversity as a standard for management.
Reference points based on maximized biodiversity are preferable to statistical parameters in meeting the objective of avoiding
the abnormal or pathological in our interactions with other species, ecosystems and the biosphere. Management to maximize
biodiversity is implemented by modifying human interactions with other biotic systems to achieve consistency in such interactions
by mimicking natural role models of sustainability. Human influence is a significant factor in today’s world and the magnitude
of such influence is illustrated by comparing humans with other species. 相似文献
9.
During the Second World War scientists and engineers were involved as never before in all technical phases of the war effort. It included intelligence, logistics and large scale automated computation. Much of this required team work which led to the adoption of interdisciplinary perspectives and found expression after the war in new fields of enquiry such as cybernetics, biophysics and artificial intelligence. 相似文献
10.
The indriid genus Propithecus comprises the sifakas, medium-sized lemurs endemic to the forests of Madagascar. Traditionally, scientists divided the genus
into only 2 or 3 species —Propithecus diadema, P. verreauxi, and, since 1988, P. tattersalli— with 4 or 5 subspecies in each of the first 2 taxa, but recent authors have suggested that many more distinct species should
be recognized. We draw from quantitative and qualitative studies of craniodental traits to evaluate further the phenetic distinctiveness
and taxonomic status of each named form of Propithecus. We recognize 9–10 species in the genus. The 4 or 5 species of the Propithecus diadema group —P. diadema, P. candidus, P. perrieri, P. edwardsi, and perhaps P. holomelas, if distinct— share several derived features, including large average body size and a mandible specialized for rotational
chewing, and clearly comprise a closely related complex. The 5 species of the Propithecus verreauxi group —P. verreauxi, P. coquereli, P. deckenii, P. coronatus, P. tattersalli— are each highly distinctive morphologically and likely do not comprise a monophyletic group. In particular, we point out
the highly distinctive cranial features of Propithecus coronatus, which researchers have traditionally largely overlooked. 相似文献
11.
Humphrey JD Coté GL Walton JR Meininger GA Laine GA 《Advances in physiology education》2005,29(2):98-102
98Emphasis on the individual investigator has fostered discovery for centuries, yet it is now recognized that the complexity of problems in the biomedical sciences and engineering requires collaborative efforts from individuals having diverse training and expertise. Various approaches can facilitate interdisciplinary interactions, but we submit that there is a critical need for a new educational paradigm for the way that we train biomedical engineers, life scientists, and mathematicians. We cannot continue to train graduate students in isolation within single disciplines, nor can we ask any one individual to learn all the essentials of biology, engineering, and mathematics. We must transform how students are trained and incorporate how real-world research and development are done-in diverse, interdisciplinary teams. Our fundamental vision is to create an innovative paradigm for graduate research and training that yields a new generation of biomedical engineers, life scientists, and mathematicians that is more diverse and that embraces and actively pursues a truly interdisciplinary, team-based approach to research based on a known benefit and mutual respect. In this paper, we describe our attempt to accomplish this via focused training in biomechanics, biomedical optics, mathematics, mechanobiology, and physiology. The overall approach is applicable, however, to most areas of biomedical research. 相似文献
12.
Complementation of an E. coli mutant auxotrophic for the branched-chain amino acids (BCAA)—valine, leucine, and isoleucine—by the ilvG gene (slr2088) of the cyanobacterium Synechocystis PCC6803 indicates that this gene encodes an active α-acetohydroxy acid synthase. Differences of response of the recombinants
to the addition of the essential amino acids suggested a lower specificity for the initial reaction of the valine/leucine
chain than for the isoleucine one. Inactivation of ilvG in Synechocystis led to a leaky phenotype, suggesting a capacity to compensate the auxotrophies by other processes. This observation is discussed
in view of the general difficulty of obtaining auxotrophs in cyanobacteria.
Received: 16 October 2001 / Accepted: 26 November 2001 相似文献
13.
The Quantum Co-Evolution Unit: An Example of ‘Awa (Kava—
Piper methysticum
G. Foster) in Hawaiian Culture. The process of co-evolution occurs in many kinds of relationships and on various scales. One example of a co-evolutionary
relationship is that of a plant and a culture with which it interacts. Such relationships are dynamic and ever changing. Researchers
have discussed this concept and its implications for decades, yet no quantifiable unit or standardized scale has been accepted
with which to measure this change. The theoretical “quantum co-evolution unit” (QCU) is proposed as the smallest measurable
scale of interactions between plants and people. A collection of QCUs for a linked plant and human population would be its
“ethnobotanical population.” This could be measured at various points in time to quantify the changing relationships between
plants and people. These models set up a structure to discuss methodologies for quantifying co-evolutionary relationships
such as are seen in the evolution of ethnobotanical populations. The co-evolving relationship between ‘awa (kava—Piper methysticum) and Hawaiian culture is used as an example to illustrate this idea. 相似文献
14.
Susan Hanna 《Ecosystems》2001,4(8):736-741
The field of resource management integrates human and ecological systems. It is currently undergoing a difficult transition
as it broadens to accommodate new values and interests. Some of the problems associated with this transition are evident in
marine ecosystems, where the management of the ecological–human interface has been hindered by a lack of basic understanding.
Using marine fisheries as examples, this paper describes the proximate and underlying causes of the human–ecological problem.
It identifies areas in which basic research is needed on the behavioral dynamics of marine resource use, including incentives,
feedbacks, management scale, monitoring and evaluation, alternative management approaches, the role of history, and human
capital. It discusses the cost of failing to invest in social science research and identifies barriers to interdisciplinary
research. Priorities for interdisciplinary research are listed.
Received 30 November 2000; accepted 20 April 2001. 相似文献
15.
Brian J. Switek 《Evolution》2010,3(3):468-476
On May 19, 2009, an international team of scientists claimed to have found one of our early primate ancestors. Dubbed Darwinius masillae, the 47 million-year-old primate was presented as “the link” that bridged a gap between early primates and our anthropoid
progenitors through a major media campaign, yet details about the way the fossil was acquired, the role media companies played
in the presentation of the fossil, and disagreements about the fossil’s interpretation generated a controversy in which scientists,
journalists, and science bloggers all played important roles. These debates were reinvigorated in the fall of 2009 when an
independent team of researchers described a related fossil primate named Afradapis longicristatus, the study of which suggested that Darwinius was much further removed from our ancestry than had been initially proposed. The discussion of these fossils will no doubt
continue, but the “Darwinius debates” of 2009 are significant in that they precipitated a long-awaited analysis of early primate relationships, illustrated
the benefits and pitfalls of “going broad” with new discoveries, and exhibited how science blogs can work with traditional
media outlets to counter exaggerated claims. 相似文献
16.
Finding better approaches to bridge field and laboratory primate research was identified as an important goal in a recent (2017) member survey of the American Society of Primatologists. Collaborative field‐captive research was identified by >60% of respondents as somewhat or very underrepresented in the Society. In this introductory essay for a special section of American Journal of Primatology, I review commonalities and differences in the papers that were requested from field‐captive primate collaborative teams. Each team approached important primate biology or welfare problems from different perspectives. The five commentaries in this section addressed how the collaborations began, scientific benefits that accrued, and insights or challenges that researchers faced in the collaboration. Despite the fact that the specific fields of inquiry were different (conservation genetics, chimpanzee captive welfare, environmental physiology, feeding biology, and reproductive physiology), the commentaries converged on the concept that an intentional, interdisciplinary approach, that included field observations and experiments informed by laboratory expertise, were essential to achieving innovative results. 相似文献
17.
Gernhard T 《Bulletin of mathematical biology》2008,70(4):1082-1097
In this paper, we investigate the standard Yule model, and a recently studied model of speciation and extinction, the “critical
branching process.” We develop an analytic way—as opposed to the common simulation approach—for calculating the speciation
times in a reconstructed phylogenetic tree. Simple expressions for the density and the moments of the speciation times are
obtained.
Methods for dating a speciation event become valuable, if for the reconstructed phylogenetic trees, no time scale is available.
A missing time scale could be due to supertree methods, morphological data, or molecular data which violates the molecular
clock. Our analytic approach is, in particular, useful for the model with extinction, since simulations of birth-death processes
which are conditioned on obtaining n extant species today are quite delicate. Further, simulations are very time consuming for big n under both models. 相似文献
18.
To be used as a predictive conservation tool, classification of animal habitats should rely on actual resource requirements
of individual species. Shreeve et al. (J Insect Conserv 5:145–161, 2001) produced a resource-based habitat classification for British butterflies, obtaining habitat association groups, whose constituent
species differed in their distribution extent, distribution change and vulnerability in Britain. To test the utility of this
approach for a group with a less-known biology, we produced a resource-based classification of habitats of Central European
macromoths. We worked with macrolepidopteran moth families, except for the megadiverse Geometridae and Noctuidae. We produced
a matrix of 178 life history attributes describing resource use by 164 species, subjected the matrix to ordination analysis,
and compared the resulting moths groupings with external ecological information. Five habitat association groups were distinguished:
I—close canopy moths, II—open canopy moths, III—grasslands moths, IV—herb-feeding hawk moths, and V—lichen feeders. The classification sustained deleting attributes related to host plants taxonomy. Groups I–III sustained control for taxonomic
positions of the moths, whereas IV and V did not. Members of the groups differed in the representation of externally obtained
habitat associations, biogeography elements, threat status, and range size. Endangered species were over-represented in groups
II and III and underrepresented in group I, in agreement with recent land cover changes across the continent. Species resources
can be used to reconstruct their habitat needs, and it is possible to scale up from life histories through habitat use to
range structures. 相似文献
19.
Colin D. MacLeod Laura Mandleberg Caroline Schweder Sarah M. Bannon Graham J. Pierce 《Hydrobiologia》2008,612(1):21-32
Approaches for modelling the distribution of animals in relation to their environment can be divided into two basic types,
those which use records of absence as well as records of presence and those which use only presence records. For terrestrial
species, presence–absence approaches have been found to produce models with greater predictive ability than presence-only
approaches. This study compared the predictive ability of both approaches for a marine animal, the harbour porpoise (Phoceoena phocoena). Using data on the occurrence of harbour porpoises in the Sea of Hebrides, Scotland, the predictive abilities of one presence–absence
approach (generalised linear modelling—GLM) and three presence-only approaches (Principal component analysis—PCA, ecological
niche factor analysis—ENFA and genetic algorithm for rule-set prediction—GARP) were compared. When the predictive ability
of the models was assessed using receiver operating characteristic (ROC) plots, the presence–absence approach (GLM) was found
to have the greatest predictive ability. However, all approaches were found to produce models that predicted occurrence significantly
better than a random model and the GLM model did not perform significantly better than ENFA and GARP. The PCA had a significantly
lower predictive ability than GLM but not the other approaches. In addition, all models predicted a similar spatial distribution.
Therefore, while models constructed using presence–absence approaches are likely to provide the best understanding of species
distribution within a surveyed area, presence-only models can perform almost as well. However, careful consideration of the
potential limitations and biases in the data, especially with regards to representativeness, is needed if the results of presence-only
models are to be used for conservation and/or management purposes.
Guest editor: V. D. Valavanis
Essential Habitat Mapping in the Mediterranean 相似文献
20.
Behaviour of simple population models under ecological processes 总被引:1,自引:0,他引:1
The two most popular and extensively-used discrete models of population growth display the generic bifurcation structure of
a hierarchy of period-doubling sequence to chaos with increasing growth rates. In this paper we show that these two models,
though they belong to a general class of one-dimensional maps, show very different dynamics when important ecological processes
such as immigration and emigration/depletion, are considered. It is important that ecologists recognize the differences between
these models before using them to describe their data—or develop optimization strategies—based on these models. 相似文献