383 research outputs found
Learning from our Multi-Stage Collaborative Autoethnography
This article is a reflection on eight, then seven, now five women’s collaborative efforts to explore the development of our own leader identities. While each of us conducts research on women and leadership, we are a diverse group of women: we were born in three different countries (United States, Paraguay, and New Zealand) and currently live in three different countries (United States, Canada, and New Zealand). We are of diverse races, sexual orientations, and generations; we have leadership experiences in a variety of disciplines and industries; and we vary in the priority we place on this study. In this paper, we review our experiences conducting research during the first three plus years of our collaborative autoethnographic study and share what we learned from those experiences. We address previously published considerations for developing collaborative autoethnographies including: the number of participants involved; the extent of involvement of the participants and the level of collaboration during the study; the collaborative approaches used in the study; and the approaches to writing. We add a reflection on our leadership practices throughout the study and on the confidentiality challenges that emerged. We also discuss how our division of the study into multiple life stages and multiple projects within the life stages has influenced our experiences and how the challenges resulting from the long duration of our study have influenced our productivity and are expected to influence our future plans. Our lessons learned should prove useful as other autoethnographic research groups begin their own research processes
Multi-timescale Solar Cycles and the Possible Implications
Based on analysis of the annual averaged relative sunspot number (ASN) during
1700 -- 2009, 3 kinds of solar cycles are confirmed: the well-known 11-yr cycle
(Schwabe cycle), 103-yr secular cycle (numbered as G1, G2, G3, and G4,
respectively since 1700); and 51.5-yr Cycle. From similarities, an
extrapolation of forthcoming solar cycles is made, and found that the solar
cycle 24 will be a relative long and weak Schwabe cycle, which may reach to its
apex around 2012-2014 in the vale between G3 and G4. Additionally, most Schwabe
cycles are asymmetric with rapidly rising-phases and slowly decay-phases. The
comparisons between ASN and the annual flare numbers with different GOES
classes (C-class, M-class, X-class, and super-flare, here super-flare is
defined as X10.0) and the annal averaged radio flux at frequency of 2.84
GHz indicate that solar flares have a tendency: the more powerful of the flare,
the later it takes place after the onset of the Schwabe cycle, and most
powerful flares take place in the decay phase of Schwabe cycle. Some
discussions on the origin of solar cycles are presented.Comment: 8 pages, 4 figure
Adaptive optics in high-contrast imaging
The development of adaptive optics (AO) played a major role in modern
astronomy over the last three decades. By compensating for the atmospheric
turbulence, these systems enable to reach the diffraction limit on large
telescopes. In this review, we will focus on high contrast applications of
adaptive optics, namely, imaging the close vicinity of bright stellar objects
and revealing regions otherwise hidden within the turbulent halo of the
atmosphere to look for objects with a contrast ratio lower than 10^-4 with
respect to the central star. Such high-contrast AO-corrected observations have
led to fundamental results in our current understanding of planetary formation
and evolution as well as stellar evolution. AO systems equipped three
generations of instruments, from the first pioneering experiments in the
nineties, to the first wave of instruments on 8m-class telescopes in the years
2000, and finally to the extreme AO systems that have recently started
operations. Along with high-contrast techniques, AO enables to reveal the
circumstellar environment: massive protoplanetary disks featuring spiral arms,
gaps or other asymmetries hinting at on-going planet formation, young giant
planets shining in thermal emission, or tenuous debris disks and micron-sized
dust leftover from collisions in massive asteroid-belt analogs. After
introducing the science case and technical requirements, we will review the
architecture of standard and extreme AO systems, before presenting a few
selected science highlights obtained with recent AO instruments.Comment: 24 pages, 14 figure
Radiative decays: a new flavour filter
Radiative decays of the orbital excitations of the ,
and to the scalars , and are shown to
provide a flavour filter, clarifying the extent of glueball mixing in the
scalar states. A complementary approach to the latter is provided by the
radiative decays of the scalar mesons to the ground-state vectors ,
and . Discrimination among different mixing scenarios is strong.Comment: 12 pages, 1 table, 0 figure
Tectonic controls on nearshore sediment accumulation and submarine canyon morphology offshore La Jolla, Southern California
CHIRP seismic and swath bathymetry data acquired offshore La Jolla, California provide an unprecedented three-dimensional view of the La Jolla and Scripps submarine canyons. Shore-parallel patterns of tectonic deformation appear to control nearshore sediment thickness and distribution around the canyons. These shore-parallel patterns allow the impact of local tectonic deformation to be separated from the influence of eustatic sea-level fluctuations. Based on stratal geometry and acoustic character, we identify a prominent angular unconformity inferred to be the transgressive surface and three sedimentary sequences: an acoustically laminated estuarine unit deposited during early transgression, an infilling or “healing-phase” unit formed during the transgression, and an upper transparent unit. Beneath the transgressive surface, steeply dipping reflectors with several dip reversals record faulting and folding along the La Jolla margin. Scripps Canyon is located at the crest of an antiform, where the rocks are fractured and more susceptible to erosion. La Jolla Canyon is located along the northern strand of the Rose Canyon Fault Zone, which separates Cretaceous lithified rocks to the south from poorly cemented Eocene sands and gravels to the north. Isopach and structure contour maps of the three sedimentary units reveal how their thicknesses and spatial distributions relate to regional tectonic deformation. For example, the estuarine unit is predominantly deposited along the edges of the canyons in paleotopographic lows that may have been inlets along barrier beaches during the Holocene sea-level rise. The distribution of the infilling unit is controlled by pre-existing relief that records tectonic deformation and erosional processes. The thickness and distribution of the upper transparent unit are controlled by long-wavelength, tectonically induced relief on the transgressive surface and hydrodynamics
The moment of truth for WIMP Dark Matter
We know that dark matter constitutes 85% of all the matter in the Universe,
but we do not know of what it is made. Amongst the many Dark Matter candidates
proposed, WIMPs (weakly interacting massive particles) occupy a special place,
as they arise naturally from well motivated extensions of the standard model of
particle physics. With the advent of the Large Hadron Collider at CERN, and a
new generation of astroparticle experiments, the moment of truth has come for
WIMPs: either we will discover them in the next five to ten years, or we will
witness the inevitable decline of WIMP paradigm.Comment: To appear in Nature (Nov 18, 2010
Microdevices for extensional rheometry of low viscosity elastic liquids : a review
Extensional flows and the underlying stability/instability mechanisms are of extreme relevance to the efficient operation of inkjet printing, coating processes and drug delivery systems, as well as for the generation of micro droplets. The development of an extensional rheometer to characterize the extensional properties of low viscosity fluids has therefore stimulated great interest of researchers, particularly in the last decade. Microfluidics has proven to be an extraordinary working platform and different configurations of potential extensional microrheometers have been proposed. In this review, we present an overview of several successful designs, together with a critical assessment of their capabilities and limitations
Controls on gut phosphatisation : the trilobites from the Weeks Formation Lagerstätte (Cambrian; Utah)
Despite being internal organs, digestive structures are frequently preserved in Cambrian Lagerstätten. However, the reasons for their fossilisation and their biological implications remain to be thoroughly explored. This is particularly true with arthropods--typically the most diverse fossilised organisms in Cambrian ecosystems--where digestive structures represent an as-yet underexploited alternative to appendage morphology for inferences on their biology. Here we describe the phosphatised digestive structures of three trilobite species from the Cambrian Weeks Formation Lagerstätte (Utah). Their exquisite, three-dimensional preservation reveals unique details on trilobite internal anatomy, such as the position of the mouth and the absence of a differentiated crop. In addition, the presence of paired pygidial organs of an unknown function is reported for the first time. This exceptional material enables exploration of the relationships between gut phosphatisation and the biology of organisms. Indeed, soft-tissue preservation is unusual in these fossils as it is restricted to the digestive structures, which indicates that the gut played a central role in its own phosphatisation. We hypothesize that the gut provided a microenvironment where special conditions could develop and harboured a source of phosphorus. The fact that gut phosphatization has almost exclusively been observed in arthropods could be explained by their uncommon ability to store ions (including phosphorous) in their digestive tissues. However, in some specimens from the Weeks Formation, the phosphatisation extends to the entire digestive system, suggesting that trilobites might have had some biological particularities not observed in modern arthropods. We speculate that one of them might have been an increased capacity for ion storage in the gut tissues, related to the moulting of their heavily-mineralised carapace
Effect of field exposure to 38-year-old residual petroleum hydrocarbons on growth, condition index, and filtration rate of the ribbed mussel, Geukensia demissa
Author Posting. © The Author(s), 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Environmental Pollution 154 (2008): 312-319, doi:10.1016/j.envpol.2007.10.008.In September 1969, the Florida barge spilled 700,000 L of No. 2 fuel oil into the
salt marsh sediments of Wild Harbor, MA. Today a substantial amount, approximately
100 kg, of moderately degraded petroleum remains within the sediment and along
eroding creek banks. The ribbed mussels, Geukensia demissa, which inhabit the salt marsh creek bank, are exposed to the spilled oil. Examination of short-term exposure was
done with transplantation of G. demissa from a control site, Great Sippewissett marsh,
into Wild Harbor. We examined the effects of long-term exposure with transplantation of
mussels from Wild Harbor into Great Sippewissett. Both the short- and long-term
exposure transplants exhibited slower growth rates, shorter mean shell lengths, lower
condition indices, and decreased filtration rates. Our results add new knowledge about
long-term consequences of spilled oil, a dimension that should be included when
assessing oil-impacted areas and developing management plans designed to restore,
rehabilitate, or replace impacted areas.This work is the result of research sponsored by NOAA National Sea Grant
College Program Office, Department of Commerce, under Grant No. NA16RG2273,
Woods Hole Oceanographic Institution Sea Grant Project No. R/P-73. Additional support was
provided by funding from the NSF-funded Research Experience for Undergraduates
program, award 0453292, an Office of Naval Research Young Investigator Award
(N00014-04-01-0029) to C. Reddy
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