1,267 research outputs found
The Transition to Superrotation in Terrestrial Atmospheres
We show that by changing a single non-dimensional number, the thermal Rossby
number, global atmospheric simulations with only axisymmetric forcing pass from
an Earth-like atmosphere to a superrotating atmosphere that more resembles the
atmospheres of Venus or Titan. The transition to superrotation occurs under
conditions in which equatorward-propagating Rossby waves generated by
baroclinic instability at intermediate and high latitudes are suppressed, which
will occur when the deformation radius exceeds the planetary radius. At large
thermal Rossby numbers following an initial, nearly axisymmetric phase, a
global baroclinic wave of zonal wavenumber one generated by mixed
barotropic-baroclinic instability dominates the eddy flux of zonal momentum.
The global wave converges eastward zonal momentum to the equator and deposits
westward momentum at intermediate latitudes during spinup and before
superrotation emerges, and the baroclinic instability ceases once superrotation
is established. A global barotropic mode of zonal wavenumber one generated by a
mix of high- and low-latitude barotropic instability is responsible for
maintaining superrotation in the statistically steady state. At intermediate
thermal Rossby numbers, momentum flux by the global baroclinic mode is
subdominant relative to smaller baroclinic modes, and thus strong superrotation
does not develop.Comment: accepted for publication in JGR-Planet
Water Supply Planning: Middle Illinois Progress Report
This report presents a summary of 1) the technical information assembled to describe existing water availability and sources of supply within the 7-county (LaSalle, Livingston, Marshall, Peoria, Putnam, Stark, and Woodford Counties) Middle Illinois River Region in central Illinois (Figures 1 and 2) and 2) the development of preliminary computer models that will be used in future studies to estimate impacts to water availability resulting from future water development in the region. Through funding by the Illinois Department of Natural Resources (IDNR), the Illinois State Water Survey (ISWS) and Illinois State Geological Survey (ISGS) prepared this document for the Middle Illinois Regional Water Supply Planning Committee (MIRWSPC) to aid in the development of a plan for meeting the future growth of water supply demands within the basin to the year 2060. It contains background information to provide an overview of management criteria and an understanding of the constraints and policies used in conducting analyses and making decisions concerning water usage. Models will be applied to a broad range of conditions, including a set of selected future water use scenarios to more fully characterize water availability within the Middle Illinois River Region to the year 2060. In addition, as the MIRWSPC deliberates and prepares its water supply planning document, the information presented in this report will be reviewed and, in some cases, additional analysis may be performed and results revised. A more complete reporting of the model development, the results of the scenario simulations, and subsequent work concerning water availability will be published at the end of that forthcoming study.
The existing technical information compiled as the first task of this study includes a review of previous analyses and publications dealing with the Middle Illinois River Regionâs water resources; collection of hydrogeological and hydrologic data, primarily as needed for modeling; and, in certain cases, additional analyses of that data, such as data mining of well records and yield analyses of surface water supply sources. This compiled information focuses on the three primary sources of water supply within the Middle Illinois River watershed: 1) direct withdrawals from the Illinois River; 2) public supply systems using the Vermilion River and off-channel reservoirs at Pontiac and Streator; and 3) groundwater from within the Middle Illinois River basin.
A companion report has been published (Meyer et al., In preparation) evaluating water demand scenarios out to 2060 for the Middle Illinois River, Northwest Illinois, and Kankakee River Regions.published or submitted for publicationis peer reviewedOpe
Chemically-defined albumin-free differentiation of human pluripotent stem cells to endothelial progenitor cells.
Human pluripotent stem cell (hPSC)-derived endothelial cells and their progenitors are important for vascular research and therapeutic revascularization. Here, we report a completely defined endothelial progenitor differentiation platform that uses a minimalistic medium consisting of Dulbecco's modified eagle medium and ascorbic acid, lacking of albumin and growth factors. Following hPSC treatment with a GSK-3ÎČ inhibitor and culture in this medium, this protocol generates more than 30% multipotent CD34+ CD31+ endothelial progenitors that can be purified to >95% CD34+ cells via magnetic activated cell sorting (MACS). These CD34+ progenitors are capable of differentiating into endothelial cells in serum-free inductive media. These hPSC-derived endothelial cells express key endothelial markers including CD31, VE-cadherin, and von Willebrand factor (vWF), exhibit endothelial-specific phenotypes and functions including tube formation and acetylated low-density lipoprotein (Ac-LDL) uptake. This fully defined platform should facilitate production of proliferative, xeno-free endothelial progenitor cells for both research and clinical applications
Effects of compressibility on driving zonal flow in gas giants
The banded structures observed on the surfaces of the gas giants are
associated with strong zonal winds alternating in direction with latitude. We
use three-dimensional numerical simulations of compressible convection in the
anelastic approximation to explore the properties of zonal winds in rapidly
rotating spherical shells. Since the model is restricted to the electrically
insulating outer envelope, we therefore neglect magnetic effects.
A systematic parametric study for various density scaleheights and Rayleigh
numbers allows to explore the dependence of convection and zonal jets on these
parameters and to derive scaling laws.
While the density stratification affects the local flow amplitude and the
convective scales, global quantities and zonal jets properties remain fairly
independent of the density stratification. The zonal jets are maintained by
Reynolds stresses, which rely on the correlation between zonal and
cylindrically radial flow components. The gradual loss of this correlation with
increasing supercriticality hampers all our simulations and explains why the
additional compressional source of vorticity hardly affects zonal flows.
All these common features may explain why previous Boussinesq models were
already successful in reproducing the morphology of zonal jets in gas giants.Comment: 17 pages, 15 figures, 2 tables, accepted for publication in Icaru
Mechanisms of jet formation on the giant planets
The giant planet atmospheres exhibit alternating prograde (eastward) and
retrograde (westward) jets of different speeds and widths, with an equatorial
jet that is prograde on Jupiter and Saturn and retrograde on Uranus and
Neptune. The jets are variously thought to be driven by differential radiative
heating of the upper atmosphere or by intrinsic heat fluxes emanating from the
deep interior. But existing models cannot account for the different flow
configurations on the giant planets in an energetically consistent manner. Here
a three-dimensional general circulation model is used to show that the
different flow configurations can be reproduced by mechanisms universal across
the giant planets if differences in their radiative heating and intrinsic heat
fluxes are taken into account. Whether the equatorial jet is prograde or
retrograde depends on whether the deep intrinsic heat fluxes are strong enough
that convection penetrates into the upper troposphere and generates strong
equatorial Rossby waves there. Prograde equatorial jets result if convective
Rossby wave generation is strong and low-latitude angular momentum flux
divergence owing to baroclinic eddies generated off the equator is sufficiently
weak (Jupiter and Saturn). Retrograde equatorial jets result if either
convective Rossby wave generation is weak or absent (Uranus) or low-latitude
angular momentum flux divergence owing to baroclinic eddies is sufficiently
strong (Neptune). The different speeds and widths of the off-equatorial jets
depend, among other factors, on the differential radiative heating of the
atmosphere and the altitude of the jets, which are vertically sheared. The
simulations have closed energy and angular momentum balances that are
consistent with observations of the giant planets.Comment: 21 pages, 10 figure
The t(8;21) chromosomal translocation in acute myelogenous leukemia modifies intranuclear targeting of the AML1/CBFalpha2 transcription factor
Targeting of gene regulatory factors to specific intranuclear sites may be critical for the accurate control of gene expression. The acute myelogenous leukemia 8;21 (AML1/ETO) fusion protein is encoded by a rearranged gene created by the ETO chromosomal translocation. This protein lacks the nuclear matrix-targeting signal that directs the AML1 protein to appropriate gene regulatory sites within the nucleus. Here we report that substitution of the chromosome 8-derived ETO protein for the multifunctional C terminus of AML1 precludes targeting of the factor to AML1 subnuclear domains. Instead, the AML1/ETO fusion protein is redirected by the ETO component to alternate nuclear matrix-associated foci. Our results link the ETO chromosomal translocation in AML with modifications in the intranuclear trafficking of the key hematopoietic regulatory factor, AML1. We conclude that misrouting of gene regulatory factors as a consequence of chromosomal translocations is an important characteristic of acute leukemias
Guidance for engendering ecosystem services for urban transformation
Growing urbanisation and climate change present a number of important challenges to ensuring more sustainable development in the future. All human activities impact on the natural environment, especially cities. How urban development is undertaken and managed has implications for present and future wellbeing. This guidance focusses on how natural capital and its associated ecosystem services (ES) can be understood within the context of the urban environment. It focuses on how different ES can be incorporated into sustainable urban development and planning, as a natural asset that can reduce peoples risk and vulnerability, and improve their wellbeing.This summary guidance aims to highlight how natural capital based ES can be seen as an âassetâ which can improve the well-being of communities, and the women and men, girls and boys that live within them.It draws on existing findings about how environmental assets such as parks, street trees, water features and private gardens can contribute to human well-being, applied to the Brazilian context through an exploratory study centred in Nova Contagem, a peripheral suburb of Belo Horizonte.It uses experience of undertaking the study to provide practical guidance in how to:-Undertake an assessment of the environmental assets present in a community-Evaluate the potential for urban environmental assets to yield ecosystem services - services such as Regulating (cooling shade), Provisioning (food and fuel), and Cultural (space for gathering / taking exercise) - and the nature of the goods, benefits, and at times dis-benefits, natural capital assets deliverThe findings of the study provide guidance around:-How people understand what the environment is, and how they value, or not, different types of urban environmental assets-The ecosystem services and dis-services they derive from the natural environment-How environmental assets interact with other assets to improve well beingThe premise of the study is that access to urban environmental assets and the ecosystem services they provide, is not equal for all within a community or a household, and in particular women and men will have different access to these and other assets. The study then also provides insights into:-Differences in women and menâs understandings of the environment and its potential for improving well being-Differences in women and menâs access to environmental assets and the ecosystem services they may provide-Actions that could be taken to improve gender equality of access to ecosystem servicesUltimately the guide seeks to provide recommendations on what local authorities and community organisations can do to ensure that the existing environmental assets are valued and protected and the beneficial services are maximised and made accessible to all, while the dis-services are minimised
Ionic diodes based on regenerated α-cellulose films deposited asymmetrically onto a microhole
Cellulose films of approximately 5 mm thickness, reconstituted from ionic liquid media onto a poly-ethylene-terephthalate (PET) film with a 5, 10, 20, or 40 mm diameter microhole, show current rectification when immersed in aqueous NaCl. For âasymmetric cellulose depositsâ this rectification, or ionic diode behaviour, is then investigated as a function of ionic strength and microhole diameter. Future applications are envisaged in sustainable cellulose-based desalination, sensing, or energy harvesting processes<br/
Common allergens of atopic dermatitis in dogs: comparative findings based on intradermal tests
Intradermal tests were performed on 58 dogs diagnosed with atopic dermatitis from 2004~2008 at the Veterinary Medical Teaching Hospital of Konkuk University, Korea. To compare the allergen distribution observed in the present investigation to the results from other studies conducted in Korea and elsewhere, the allergens were grouped according to their kinds. There was no significant difference in gender distribution among the dogs. The most common breeds among the 58 dogs were Maltese (n = 11) and Shih-tzu (n = 11). The average age was 4.8 years. The most frequently produced a positive reaction on the intradermal tests was mold (67.3%) followed by house dust (54.5%) and house dust mites (49.1%). The present study found a low distribution of dogs allergic to various outdoor allergens compared to studies performed in other countries; this may reflect differences in living conditions for dogs living in Korea
Structure of the first representative of Pfam family PF04016 (DUF364) reveals enolase and Rossmann-like folds that combine to form a unique active site with a possible role in heavy-metal chelation.
The crystal structure of Dhaf4260 from Desulfitobacterium hafniense DCB-2 was determined by single-wavelength anomalous diffraction (SAD) to a resolution of 2.01â
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using the semi-automated high-throughput pipeline of the Joint Center for Structural Genomics (JCSG) as part of the NIGMS Protein Structure Initiative (PSI). This protein structure is the first representative of the PF04016 (DUF364) Pfam family and reveals a novel combination of two well known domains (an enolase N-terminal-like fold followed by a Rossmann-like domain). Structural and bioinformatic analyses reveal partial similarities to Rossmann-like methyltransferases, with residues from the enolase-like fold combining to form a unique active site that is likely to be involved in the condensation or hydrolysis of molecules implicated in the synthesis of flavins, pterins or other siderophores. The genome context of Dhaf4260 and homologs additionally supports a role in heavy-metal chelation
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