561 research outputs found
Minimizing the stochasticity of halos in large-scale structure surveys
In recent work (Seljak, Hamaus and Desjacques 2009) it was found that
weighting central halo galaxies by halo mass can significantly suppress their
stochasticity relative to the dark matter, well below the Poisson model
expectation. In this paper we extend this study with the goal of finding the
optimal mass-dependent halo weighting and use -body simulations to perform a
general analysis of halo stochasticity and its dependence on halo mass. We
investigate the stochasticity matrix, defined as , where is the dark matter
overdensity in Fourier space, the halo overdensity of the -th
halo mass bin and the halo bias. In contrast to the Poisson model
predictions we detect nonvanishing correlations between different mass bins. We
also find the diagonal terms to be sub-Poissonian for the highest-mass halos.
The diagonalization of this matrix results in one large and one low eigenvalue,
with the remaining eigenvalues close to the Poisson prediction ,
where is the mean halo number density. The eigenmode with the lowest
eigenvalue contains most of the information and the corresponding eigenvector
provides an optimal weighting function to minimize the stochasticity between
halos and dark matter. We find this optimal weighting function to match linear
mass weighting at high masses, while at the low-mass end the weights approach a
constant whose value depends on the low-mass cut in the halo mass function.
Finally, we employ the halo model to derive the stochasticity matrix and the
scale-dependent bias from an analytical perspective. It is remarkably
successful in reproducing our numerical results and predicts that the
stochasticity between halos and the dark matter can be reduced further when
going to halo masses lower than we can resolve in current simulations.Comment: 17 pages, 14 figures, matched the published version in Phys. Rev. D
including one new figur
Coordinating government and community support for community language teaching in Australia: Overview with special attention to New South Wales
An overview of formal government language-in-education planning for community languages (CLs) that has been undertaken in Australia and New South Wales is provided, moving from the more informal programmes provided in the 1980s to school-oriented programmes and training at the turn of the century. These programmes depend on community support; for many of the teachers from the communities, methodological training is needed to complement their language and cultural skills. At the same time, Commonwealth (Federal) and State support for CL programmes has improved their quality and provides students with opportunities to study CLs at the senior secondary matriculation level. The paper concludes with specific recommendations for greater recognition of CL schools and for greater attention to CL teacher preparation
Language and scientific communication: The case of the reprint request
This paper reports on a study of Reprint Requests (RRs). It is estimated that tens of millions of RRs are mailed each year, most being triggered by Current Contents . A sample of RRs generated by three papers, plus a questionnaire-survey of the requesters for one paper, form the basis of this study into language use patterns in the RR genre. English is ubiquitous, German and French infrequent, Russian and Spanish rare. This language data is significant because it provides unit-level language decision making (as opposed to that at other levels). Various applications of RR research are discussed, including its relevance to the issue of “Third World Science”.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43668/1/11192_2005_Article_BF02017177.pd
Development and characterization of microsatellite loci for Ocotea species (Lauraceae) threatened with extinction
The Atlantic rainforest species Ocotea catharinensis, Ocotea odorifera, and Ocotea porosa have been extensively harvested in the past for timber and oil extraction and are currently listed as threatened due to overexploitation. To investigate the genetic diversity and population structure of these species, we developed 8 polymorphic microsatellite markers for O. odorifera from an enriched microsatellite
library by using 2 dinucleotide repeats. The microsatellite markers were tested for cross-amplification in O. catharinensis and O. porosa. The average number of alleles per locus was 10.2, considering all
loci over 2 populations of O. odorifera. Observed and expected heterozygosities for O. odorifera ranged from 0.39 to 0.93 and 0.41 to 0.92 across populations, respectively. Cross-amplification of all loci
was successfully observed in O. catharinensis and O. porosa except 1 locus that was found to lack polymorphism in O. porosa. Combined probabilities of identity in the studied Ocotea species were very low ranging from 1.0 x 10-24 to 7.7 x 10-24. The probability of exclusion over all loci estimated for O. odorifera indicated a 99.9% chance of correctly excluding a random nonparent individual. The microsatellite markers described in this study have high information content and will be useful
for further investigations on genetic diversity within these species and for subsequent conservation purposes13351385142COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESsem informaçã
Towards Activity Context using Software Sensors
Service-Oriented Computing delivers the promise of configuring and
reconfiguring software systems to address user's needs in a dynamic way.
Context-aware computing promises to capture the user's needs and hence the
requirements they have on systems. The marriage of both can deliver ad-hoc
software solutions relevant to the user in the most current fashion. However,
here it is a key to gather information on the users' activity (that is what
they are doing). Traditionally any context sensing was conducted with hardware
sensors. However, software can also play the same role and in some situations
will be more useful to sense the activity of the user. Furthermore they can
make use of the fact that Service-oriented systems exchange information through
standard protocols. In this paper we discuss our proposed approach to sense the
activity of the user making use of software
History of oceanic front development in the New Zealand sector of the Southern Ocean during the Cenozoic--a synthesis
The New Zealand sector of the Southern Ocean (NZSSO) has opened about the Indian-Pacific spreading ridge throughout the Cenozoic. Today the NZSSO is characterised by broad zonal belts of antarctic (cold), subantarctic (cool), and subtropical (warm) surface-water masses separated by prominent oceanic fronts: the Subtropical Front (STF) c. 43deg.S, Subantarctic Front (SAF) c. 50deg.S, and Antarctic Polar Front (AAPF) c. 60deg.S. Despite a meagre database, the broad pattern of Cenozoic evolution of these fronts is reviewed from the results of Deep Sea Drilling Project-based studies of sediment facies, microfossil assemblages and diversity, and stable isotope records, as well as from evidence in onland New Zealand Cenozoic sequences. Results are depicted schematically on seven paleogeographic maps covering the NZSSO at 10 m.y. intervals through the Cenozoic.
During the Paleocene and most of the Eocene (65-35 Ma), the entire NZSSO was under the influence of warm to cool subtropical waters, with no detectable oceanic fronts. In the latest Eocene (c. 35 Ma), a proto-STF is shown separating subantarctic and subtropical waters offshore from Antarctica, near 65deg.S paleolatitude. During the earliest Oligocene, this front was displaced northwards by development of an AAPF following major global cooling and biotic turnover associated with ice sheet expansion to sea level on East Antarctica. Early Oligocene full opening (c. 31 Ma) of the Tasmanian gateway initiated vigorous proto-circum-Antarctic flow of cold/cool waters, possibly through a West Antarctic seaway linking the southern Pacific and Atlantic Oceans, including detached northwards "jetting" onto the New Zealand plateau where condensation and unconformity development was widespread in cool-water carbonate facies. Since this time, a broad tripartite division of antarctic, subantarctic, and subtropical waters has existed in the NZSSO, including possible development of a proto-SAF within the subantarctic belt. In the Early-early Middle Miocene (25-15 Ma), warm subtropical waters expanded southwards into the northern NZSSO, possibly associated with reduced ice volume on East Antarctica but particularly with restriction of the Indonesian gateway and redirection of intensified warm surface flows southwards into the Tasman Sea, as well as complete opening of the Drake gateway by 23 Ma allowing more complete decoupling of cool circum-Antarctic flow from the subtropical waters. During the late Middle-Late Miocene (15-5 Ma), both the STF and SAF proper were established in their present relative positions across and about the Campbell Plateau, respectively, accompanying renewed ice buildup on East Antarctica and formation of a permanent ice sheet on West Antarctica, as well as generally more expansive and intensified circum-Antarctic flow.
The ultimate control on the history of oceanic front development in the NZSSO has been plate tectonics through its influence on the paleogeographic changes of the Australian-New Zealand-Antarctic continents and their intervening oceanic basins, the timing of opening and closing of critical seaways, the potential for submarine ridges and plateaus to exert some bathymetric control on the location of fronts, and the evolving ice budget on the Antarctic continent. The broad trends of the Cenozoic climate curve for New Zealand deduced from fossil evidence in the uplifted marine sedimentary record correspond well to the principal paleoceanographic events controlling the evolution and migration of the oceanic fronts in the NZSSO
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The programming of sequences of saccades
Saccadic eye movements move the high-resolution fovea to point at regions of interest. Saccades can only be generated serially (i.e., one at a time). However, what remains unclear is the extent to which saccades are programmed in parallel (i.e., a series of such moments can be planned together) and how far ahead such planning occurs. In the current experiment, we investigate this issue with a saccade contingent preview paradigm. Participants were asked to execute saccadic eye movements in response to seven small circles presented on a screen. The extent to which participants were given prior information about target locations was varied on a trial-by-trial basis: participants were aware of the location of the next target only, the next three, five, or all seven targets. The addition of new targets to the display was made during the saccade to the next target in the sequence. The overall time taken to complete the sequence was decreased as more targets were available up to all seven targets. This was a result of a reduction in the number of saccades being executed and a reduction in their saccade latencies. Surprisingly, these results suggest that, when faced with a demand to saccade to a large number of target locations, saccade preparation about all target locations is carried out in paralle
UbiqLog: a generic mobile phone based life-log framework
Smart phones are conquering the mobile phone market; they are not just phones they also act as media players, gaming consoles, personal calendars, storage, etc. They are portable computers with fewer computing capabilities than personal computers. However unlike personal computers users can carry their smartphone with them at all times. The ubiquity of mobile phones and their computing capabilities provide an opportunity of using them as a life logging device. Life-logs (personal e-memories) are used to record users' daily life events and assist them in memory augmentation. In a more technical sense, life-logs sense and store users' contextual information from their environment through sensors, which are core components of life-logs. Spatio-temporal aggregation of sensor information can be mapped to users' life events. We propose UbiqLog, a lightweight, configurable and extendable life-log framework that uses mobile phone as a device for life logging. The proposed framework extends previous research in this field, which investigated mobile phones as life-log tool through continuous sensing. Its openness in terms of sensor configuration allows developers to create exible, multipurpose life-log tools. In addition to that this framework contains a data model and an architecture, which can be used as reference model for further life-log development, including its extension to other devices, such as ebook readers, T.V.s, etc
Unresolved issues and new challenges in teaching English to young learners:the case of South Korea
The introduction of languages, especially English, into the primary curriculum around the world has been one of the major language-in-education policy developments in recent years. In countries where English has been compulsory for a number of years, the question arises as to what extent the numerous and well-documented challenges faced by the initial implementation of early language learning policies have been overcome and whether new challenges have arisen as policies have become consolidated. This article therefore focuses on South Korea, where English has been compulsory in primary school since 1997. The issues raised by the introduction of English into the primary curriculum are reviewed and the current situation in South Korea is investigated. The results of a mixed methods study using survey data from 125 Korean primary school teachers, together with data from a small-scale case study of one teacher are presented. The study shows that, while some of the initial problems caused by the introduction of early language learning appear to have been addressed, other challenges persist. Moreover, the data reveal the emergence of a number of new challenges faced by primary school teachers of English as they seek to implement government policy
Success or failure of primary second/foreign language programmes in Asia: What do the data tell us?
Primary school second/foreign language (SL/FL) programmes in Asia, as well as in other parts of the world, are becoming more common, with many targeting English as the SL or FL. The pressures for such English language programmes come from top-down notions that in a globalised world English is required for societies to be competitive, especially with Asian neighbours, and bottom-up pressures from parents who see English as the key to educational success for their children. In many polities, these forces have resulted in support for policies that introduce early primary school English teaching curricula for all students and have led to parents spending large sums of money on private tutoring or out-of-school tuition. This study reviews the results of nine language planning studies from the Asian region that set out to examine questions such as 'Is this trend towards early primary SL or FL education (mainly English) realistic or is it unattainable and a waste of resources? Do children really benefit from these programmes? What needs to be done to foster learners' success?' These issues are viewed from a language planning and policy perspective through an examination of the language-in-education policy types required for the development of successful programmes. The policies of a number of Asian countries are used as case studies to illustrate this issue
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