815 research outputs found
Prerequisites for Successful Fiscal Reform: Some Preliminary Results
Journal of Public Budgeting, Accounting and Financial Management, Winter 1998.Refereed Journal ArticleThis paper examines whether any relationship exists between
success or failure of policy reform on the one hand, and various
political/economic conditions in place at the time of reform on the other.
Nineteen countries were scored using three financial variables to measure the
degree of success or failure of the reform. The independent variables were
country scores for ten different economic and political conditions. The
independent variables were used to try and predict a priori which of the nineteen
countries would succeed and which would fail. Eighteen of the nineteen
countries were correctly placed into their respective success group. However
only three of the ten conditions appeared important in predicting success: a
visionary leader, a crisis, and a comprehensive program. Other writers have
suggested different sets of predicting variables
A Bima Array Survey of Molecules in Comets Linear (C/2002 T7) and Neat (C/2001 Q4)
We present an interferometric search for large molecules, including methanol,
methyl cyanide, ethyl cyanide, ethanol, and methyl formate in comets LINEAR
(C/2002 T7) and NEAT (C/2001 Q4) with the Berkeley-Illinois-Maryland
Association (BIMA) array. In addition, we also searched for transitions of the
simpler molecules CS, SiO, HNC, HN13C and 13CO . We detected transitions of
methanol and CS around Comet LINEAR and one transition of methanol around Comet
NEAT within a synthesized beam of ~20''. We calculated the total column density
and production rate of each molecular species using the variable temperature
and outflow velocity (VTOV) model described by Friedel et al.(2005).Considering
the molecular production rate ratios with respect to water, Comet T7 LINEAR is
more similar to Comet Hale-Bopp while Comet Q4 NEAT is more similar to Comet
Hyakutake. It is unclear, however, due to such a small sample size, whether
there is a clear distinction between a Hale-Bopp and Hyakutake class of comet
or whether comets have a continuous range of molecular production rate ratios.Comment: Accepted for Publication in the Astrophysical Journa
Unveiling the Circumstellar Envelope and Disk: A Sub-Arcsecond Survey of Circumstellar Structures
We present the results of a 2.7 mm continuum interferometric survey of 24
young stellar objects in 11 fields. The target objects range from deeply
embedded Class 0 sources to optical T Tauri sources. This is the first
sub-arcsecond survey of the 2.7 mm dust continuum emission from young, embedded
stellar systems. The images show a diversity of structure and complexity. The
optically visible T Tauri stars (DG Tauri, HL Tauri, GG Tauri,and GM Aurigae)
have continuum emission dominated by compact, less than 1", circumstellar
disks. The more embedded near-infrared sources (SVS13 and L1551 IRS5) have
continuum emission that is extended and compact. The embedded sources (L1448
IRS3, NGC1333 IRAS2, NGC1333 IRAS4, VLA1623, and IRAS 16293-2422) have
continuum emission dominated by the extended envelope, typically more than 85%.
In fact, in many of the deeply embedded systems it is difficult to uniquely
isolate the disk emission component from the envelope extending inward to AU
size scales. All of the target embedded objects are in multiple systems with
separations on scales of 30" or less. Based on the system separation, we place
the objects into three categories: separate envelope (separation > 6500 AU),
common envelope (separation 150-3000 AU), and common disk (separation < 100
AU). These three groups can be linked with fragmentation events during the star
formation process: separate envelopes from prompt initial fragmentation and the
separate collapse of a loosely condensed cloud, common envelopes from
fragmentation of a moderately centrally condensed spherical system, and common
disk from fragmentation of a high angular momentum circumstellar disk.Comment: 47 Pages, 18 Figures, ApJ accepte
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Innovative Strategy For Long Term Monitoring Of Metal And Radionuclide Plumes
Many government and private industry sites that were once contaminated with radioactive and chemical wastes cannot be cleaned up enough to permit unrestricted human access. The sites will require long term management, in some cases indefinitely, leaving site owners with the challenge of protecting human health and environmental quality at these "legacy" sites. Long-term monitoring of groundwater contamination is one of the largest projected costs in the life cycle of environmental management at the Savannah River Site, the larger DOE complex, and many large federal and private sites. There is a need to optimize the performance and manage the cost of long term surveillance and monitoring at their sites. Currently, SRNL is initiating a pilot field test using alternative protocols for long term monitoring of metals and radionuclides. A key component of the approach is that monitoring efforts are focused on measurement of low cost metrics related to hydrologic and chemical conditions that control contaminant migration. The strategy combines careful monitoring of hydrologic boundary conditions with measurement of master variables such as chemical surrogates along with a smaller number of standard well analyses. In plumes contaminated with metals, master variables control the chemistry of the groundwater system, and include redox variables (ORP, DO, chemicals), pH, specific conductivity, biological community (breakdown/decay products), and temperature. Significant changes in these variables will result in conditions whereby the plume may not be stable and therefore can be used to predict possible plume migration. Conversely, concentration measurements for all types of contaminants in groundwater are a lagging indicator plume movement - major changes contaminant concentrations indicate that contamination has migrated. An approach based on measurement of master variables and explicit monitoring of hydrologic boundary conditions combined with traditional metrics should lead to improved monitoring while simultaneously reducing costs. This paradigm is being tested at the SRS F-Area where an innovative passive remedial system is being monitored and evaluated over the long term prior to traditional regulatory closure. Contaminants being addressed at this site are uranium, strontium-90, iodine-129, and tritium. We believe that the proposed strategies will be more effective in early identification of potential risks; these strategies will also be cost effective because controlling variables are relatively simple to measure. These variables also directly reflect the evolution of the plume through time, so that the monitoring strategy can be modified as the plume 'ages'. This transformational long-term monitoring paradigm will generate large cost savings to DOE, other federal agencies and industry and will provide improved performance and leading indicators of environmental management performance
β2M Signals Monocytes Through Non-Canonical TGFβ Receptor Signal Transduction.
Rationale: Circulating monocytes can have pro-inflammatory or pro-reparative phenotypes. The
endogenous signaling molecules and pathways that regulate monocyte polarization in vivo are poorly
understood. We have shown that platelet derived beta-2 microglobulin (β2M) and transforming growth
factor beta (TGFβ) have opposing effects on monocytes by inducing inflammatory and reparative
phenotypes respectively, but each bind and signal through the same receptor. We now define the signaling
pathways involved.
Objective: To determine the molecular mechanisms and signal transduction pathways by which β2M and
TGFβ regulate monocyte responses both in vitro and in vivo.
Methods and Results: Wild-type (WT) and platelet specific β2M knockout (Plt-β2M-/-) mice were treated
intravenously with either β2M or TGFβ to increase plasma concentrations to those in cardiovascular
diseases. Elevated plasma β2M increased pro-inflammatory monocytes, while increased plasma TGFβ
increased pro-reparative monocytes. TGFβ receptor (TGFβR) inhibition blunted monocyte responses to
both β2M and TGFβ in vivo. Using imaging flow cytometry, we found that β2M decreased monocyte
SMAD2/3 nuclear localization, while TGFβ promoted SMAD nuclear translocation, but decreased noncanonical/
inflammatory (JNK and NFκB nuclear localization). This was confirmed in vitro using both
imaging flow cytometry and immunoblots. β2M, but not TGFβ, promoted ubiquitination of SMAD3 and
SMAD4, that inhibited their nuclear trafficking. Inhibition of ubiquitin ligase activity blocked noncanonical
SMAD-independent monocyte signaling and skewed monocytes towards a pro-reparative
monocyte response.
Conclusions: Our findings indicate that elevated plasma β2M and TGFβ dichotomously polarize
monocytes. Furthermore, these immune molecules share a common receptor, but induce SMAD-dependent
canonical signaling (TGFβ) versus non-canonical SMAD-independent signaling (β2M) in a ubiquitin ligase
dependent manner. This work has broad implications as β2M is increased in several inflammatory
conditions, while TGFβ is increased in fibrotic diseases.pre-print3451 K
CARMA Large Area Star Formation Survey: Project Overview with Analysis of Dense Gas Structure and Kinematics in Barnard 1
We present details of the CARMA Large Area Star Formation Survey (CLASSy),
while focusing on observations of Barnard 1. CLASSy is a CARMA Key Project that
spectrally imaged N2H+, HCO+, and HCN (J=1-0 transitions) across over 800
square arcminutes of the Perseus and Serpens Molecular Clouds. The observations
have angular resolution near 7" and spectral resolution near 0.16 km/s. We
imaged ~150 square arcminutes of Barnard 1, focusing on the main core, and the
B1 Ridge and clumps to its southwest. N2H+ shows the strongest emission, with
morphology similar to cool dust in the region, while HCO+ and HCN trace several
molecular outflows from a collection of protostars in the main core. We
identify a range of kinematic complexity, with N2H+ velocity dispersions
ranging from ~0.05-0.50 km/s across the field. Simultaneous continuum mapping
at 3 mm reveals six compact object detections, three of which are new
detections. A new non-binary dendrogram algorithm is used to analyze dense gas
structures in the N2H+ position-position-velocity (PPV) cube. The projected
sizes of dendrogram-identified structures range from about 0.01-0.34 pc.
Size-linewidth relations using those structures show that non-thermal
line-of-sight velocity dispersion varies weakly with projected size, while rms
variation in the centroid velocity rises steeply with projected size. Comparing
these relations, we propose that all dense gas structures in Barnard 1 have
comparable depths into the sky, around 0.1-0.2 pc; this suggests that
over-dense, parsec-scale regions within molecular clouds are better described
as flattened structures rather than spherical collections of gas. Science-ready
PPV cubes for Barnard 1 molecular emission are available for download.Comment: Accepted to The Astrophysical Journal (ApJ), 51 pages, 27 figures
(some with reduced resolution in this preprint); Project website is at
http://carma.astro.umd.edu/class
MUSTANG 3.3 Millimeter Continuum Observations of Class 0 Protostars
We present observations of six Class 0 protostars at 3.3 mm (90 GHz) using
the 64-pixel MUSTANG bolometer camera on the 100-m Green Bank Telescope. The
3.3 mm photometry is analyzed along with shorter wavelength observations to
derive spectral indices (S_nu ~ nu^alpha) of the measured emission. We utilize
previously published dust continuum radiative transfer models to estimate the
characteristic dust temperature within the central beam of our observations. We
present constraints on the millimeter dust opacity index, beta, between 0.862
mm, 1.25 mm, and 3.3 mm. Beta_mm typically ranges from 1.0 to 2.4 for Class 0
sources. The relative contributions from disk emission and envelope emission
are estimated at 3.3 mm. L483 is found to have negligible disk emission at 3.3
mm while L1527 is dominated by disk emission within the central beam. The
beta_mm^disk <= 0.8 - 1.4 for L1527 indicates that grain growth is likely
occurring in the disk. The photometry presented in this paper may be combined
with future interferometric observations of Class 0 envelopes and disks.Comment: 19 pages, 3 figures, AJ accepted, in pres
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