4,480 research outputs found
LEAF AREA INDEX RELATED TO WEED SUPPRESSION IN UPLAND TARO
LEAF AREA INDEX RELATED TO WEED SUPPRESSION IN UPLAND TAR
Globular Clusters: DNA of Early-Type galaxies?
This paper explores if the mean properties of Early-Type Galaxies (ETG) can
be reconstructed from "genetic" information stored in their GCs (i.e., in their
chemical abundances, spatial distributions and ages). This approach implies
that the formation of each globular occurs in very massive stellar
environments, as suggested by some models that aim at explaining the presence
of multi-populations in these systems. The assumption that the relative number
of globular clusters to diffuse stellar mass depends exponentially on chemical
abundance, [Z/H], and the presence of two dominant GC sub-populations blue and
red, allows the mapping of low metallicity halos and of higher metallicity (and
more heterogeneous) bulges. In particular, the masses of the low-metallicity
halos seem to scale up with dark matter mass through a constant. We also find a
dependence of the globular cluster formation efficiency with the mean projected
stellar mass density of the galaxies within their effective radii. The analysis
is based on a selected sub-sample of galaxies observed within the ACS Virgo
Cluster Survey of the {\it Hubble Space Telescope}. These systems were grouped,
according to their absolute magnitudes, in order to define composite fiducial
galaxies and look for a quantitative connection with their (also composite)
globular clusters systems. The results strengthen the idea that globular
clusters are good quantitative tracers of both baryonic and dark matter in
ETGs.Comment: 20 pages, 28 figures and 5 table
Evolution of the Socio-cognitive Structure of Knowledge Management (1986â2015): An Author Co-citation Analysis
Purpose: The evolution of the socio-cognitive structure of the field of knowledge management (KM) during the period 1986â2015 is described.
Design/methodology/approach: Records retrieved from Web of Science were submitted to author co-citation analysis (ACA) following a longitudinal perspective as of the following time slices: 1986â1996, 1997â2006, and 2007â2015. The top 10% of most cited first authors by sub-periods were mapped in bibliometric networks in order to interpret the communities formed and their relationships.
Findings: KM is a homogeneous field as indicated by networks results. Nine classical authors are identified since they are highly co-cited in each sub-period, highlighting Ikujiro Nonaka as the most influential authors in the field. The most significant communities in KM are devoted to strategic management, KM foundations, organisational learning and behaviour, and organisational theories. Major trends in the evolution of the intellectual structure of KM evidence a technological influence in 1986â1996, a strategic influence in 1997â2006, and finally a sociological influence in 2007â2015.
Research limitations: Describing a field from a single database can offer biases in terms of output coverage. Likewise, the conference proceedings and books were not used and the analysis was only based on first authors. However, the results obtained can be very useful to understand the evolution of KM research.
Practical implications: These results might be useful for managers and academicians to understand the evolution of KM field and to (re)define research activities and organisational projects.
Originality/value: The novelty of this paper lies in considering ACA as a bibliometric technique to study KM research. In addition, our investigation has wider time coverage than earlier articles
An extremely high velocity molecular jet surrounded by an ionized cavity in the protostellar source Serpens SMM1
We report ALMA observations of a one-sided, high-velocity (80 km
s) CO() jet powered by the intermediate-mass
protostellar source Serpens SMM1-a. The highly collimated molecular jet is
flanked at the base by a wide-angle cavity; the walls of the cavity can be seen
in both 4 cm free-free emission detected by the VLA and 1.3 mm thermal dust
emission detected by ALMA. This is the first time that ionization of an outflow
cavity has been directly detected via free-free emission in a very young,
embedded Class 0 protostellar source that is still powering a molecular jet.
The cavity walls are ionized either by UV photons escaping from the accreting
protostellar source, or by the precessing molecular jet impacting the walls.
These observations suggest that ionized outflow cavities may be common in Class
0 protostellar sources, shedding further light on the radiation, outflow, and
jet environments in the youngest, most embedded forming stars.Comment: 6 pages, 4 figures, accepted for publication in the Astrophysical
Journal Letter
Distributed perfection for a group of legged robots
Perception problem in robotics has been usually faced from the individual perspective, in this work we present preliminary results of a shared perception mechanism for a group of legged robots working is a dynamic scenario. The experiments has been conducted using a group of aiBo robots in the RoboCup environment. Each individual robot has its own perception of a common interesting feature, the ball, and they al together build a shared perceptio
Un Camino Solitario! / A Lonely Road!: Chicana/o Faculty Storytelling and Counterstorytelling in Academia
This volume brings together the latest research and scholarship on Latinos in the United States. This book is special in terms of the broad scope of topics covered and methodologies employed in pursuit of knowledge about Latino students. This collection is also unique in that it features the work of more than a dozen Latino scholarsâboth early-career and establishedâapplying their research expertise to investigate and elucidate the educational experiences of Latinos in the United States. The themes that are discussed in the chapters of The Education of the Hispanic Population: Selected Essays, reflect the wide-ranging discussions that are occurring in schools and school districts across the country and issues that are being carefully investigated by researchers who are committed to contributing thoughtful and meaningful scholarship of consequence for improving conditions for Latino youth
Experimental simulation of simultaneous vision
Purpose. To present and validate a prototype of an optical instrument that allows experimental simulation of pure bifocal vision. To evaluate the influence of different power additions on image contrast and visual acuity. Methods. The instrument provides the eye with two superimposed images, aligned and with the same magnification, but with different defocus states. Subjects looking through the instrument are able to experience pure simultaneous vision, with adjustable refractive correction and addition power. The instrument is used to investigate the impact of the amount of addition of an ideal bifocal simultaneous vision correction, both on image contrast and on visual performance. The instrument is validated through computer simulations of the letter contrast and by equivalent optical experiments with an artificial eye (camera). Visual acuity (VA) was measured in four subjects (age: 34.3 ± 3.4 years; spherical error: -2.1 ± 2.7 diopters [D]) for low and high contrast letters and different amounts of addition. Results. The largest degradation in contrast and visual acuity (~25%) occurred for additions around ±2 D, while additions of ±4 D produced lower degradation (14%). Low additions (1-2 D) result in lower VA than high additions (3-4 D). Conclusions. A simultaneous vision instrument is an excellent tool to simulate bifocal vision and to gain understanding of multifocal solutions for presbyopia. Simultaneous vision induces a pattern of visual performance degradation, which is well predicted by the degradation found in image quality. Neural effects, claimed to be crucial in the patients' tolerance of simultaneous vision, can be therefore compared with pure optical effects. Copyright 2013 The Association for Research in Vision and Ophthalmology, Inc.Supported by Spanish Government Grant FIS2011-25637 and European Advanced Grant ERC-2011-AdG-294099 to SM.Peer Reviewe
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