543 research outputs found
Some growth regulator and cluster thinning effects on berry set and size, berry quality, and annual productivity of de Chaunac grapes
Prebloom thinning of de Chaunac grapes (a French hybrid cultivar) to one or two proximal flower clusters per fruitful shoot generally improved berry quality in the year of treatment and increased vine yields in the subsequent year. Yield reduction in the year of ,thinning was minimized by small increases in berry set and berry size. Overall, vines thinned for three consecutive years yielded about 18 % more sugar than comparable unthinned vines. However, in the second of the three seasons, shoots thinned to a single proximal cluster exhibited poorer set on that cluster than when two clusters remained. This and other observations led to the conclusion that within-shoot competition is less critical than expected and that a general reduction in crop load may be as effective as detailed thinning. Chlormequat (CCC) treatment increased berry set on .thinned and unthinned vines but reduced berry size (weight) and juice quality. Conversely, gibberellic acid (GA3) reduced berry set, increased berry weight, and improved juice quality. CCC and GA3 were counteractive when applied to ,the same vines. In subsequent seasons the GA3 .treatment effec.ts were less dramatic. GA3 reduced juice acidity in one season and increased juice soluble solids in another. Benzyladenine applied with or without GA3 proved to be without effect.L'effet de phytorégulateurs et l'éclaircissement des grappes sur la nouaison, la grosseur et quallté des baies, et le rendement du cépage de ChaunacL'éclaircissement pré-floral du cépage de Chaunac (hybride français) à une ou deux grappes par rameau fructifère a généralement augmenté la qualité des fruits l'année du traitement et les rendements l'année suivante. Les réductions de rendement l'année de l'éclaircissement étaient minimisées par une légère augmentation de la nouaison et de la grosseur des baies. Les vignes soumises à l'éclaircissement durant trois années consécutives ont produit environ 18 0/o plus de sucre que les vignes témoins. Cependant dans la deuxième saison les rameaux éclaircies à une seule grappe proximale avaient une moins bonne nouaison que les rameaux ou deux grappes avaient été laissées. Cette observation ainsi que d'autres amènent à conclure que la compétition sur le même rameau est moins importante qu'on ne le croyait et qu'une réduction générale de la récolte pourrait être aussi efficace qu'un éclaircissement en détail.Le chlorméquat (CCC) a augmenté la nouaison des vignes éclaircies et non-éclaircies mais il a réduit la grosseur (poids) et la qualité des baies. Contrairement, l'acide gibbérellique (GA3) a réduit la nouaison, augmenté le poids des baies et amélioré la qualité du jus. Appliqués sur les mêmes plants, les effets du CCC et du GA3 se sont annulés. Les traitements au GA8 en 1977 et 1978 ont eu des effets moins prononcés. Le GA3 a réduit l'acidité du jus en 1977 et augmenté la teneur en solides solubles en 1978. La benzyladénine, appliquée avec ou sans GA3, a été sans effet
First Acetic Acid Survey with CARMA in Hot Molecular Cores
Acetic acid (CHCOOH) has been detected mainly in hot molecular cores
where the distribution between oxygen (O) and nitrogen (N) containing molecular
species is co-spatial within the telescope beam. Previous work has presumed
that similar cores with co-spatial O and N species may be an indicator for
detecting acetic acid. However, does this presumption hold as higher spatial
resolution observations become available of large O and N-containing molecules?
As the number of detected acetic acid sources is still low, more observations
are needed to support this postulate. In this paper, we report the first acetic
acid survey conducted with the Combined Array for Research in Millimeter-wave
Astronomy (CARMA) at 3 mm wavelengths towards G19.61-0.23, G29.96-0.02 and IRAS
16293-2422. We have successfully detected CHCOOH via two transitions toward
G19.61-0.23 and tentatively confirmed the detection toward IRAS 16293-2422 A.
The determined column density of CHCOOH is 2.0(1.0)
cm and the abundance ratio of CHCOOH to methyl formate (HCOOCH)
is 2.2(0.1) toward G19.61-0.23. Toward IRAS 16293 A, the
determined column density of CHCOOH is 1.6
cm and the abundance ratio of CHCOOH to methyl formate (HCOOCH)
is 1.0 both of which are consistent with abundance
ratios determined toward other hot cores. Finally, we model all known line
emission in our passband to determine physical conditions in the regions and
introduce a new metric to better reveal weak spectral features that are blended
with stronger lines or that may be near the 1-2 detection limit.Comment: 28 pages, 8 figures, accepted for publication in the ApJ; Revised
citation in session 2, references remove
Observational Results of a Multi-Telescope Campaign in Search of Interstellar Urea [(NH)CO]
In this paper, we present the results of an observational search for gas
phase urea [(NH)CO] observed towards the Sgr B2(N-LMH) region. We show
data covering urea transitions from 100 GHz to 250 GHz from five
different observational facilities: BIMA, CARMA, the NRAO 12 m telescope, the
IRAM 30 m telescope, and SEST. The results show that the features ascribed to
urea can be reproduced across the entire observed bandwidth and all facilities
by best fit column density, temperature, and source size parameters which vary
by less than a factor of 2 between observations merely by adjusting for
telescope-specific parameters. Interferometric observations show that the
emission arising from these transitions is cospatial and compact, consistent
with the derived source sizes and emission from a single species. Despite this
evidence, the spectral complexity, both of (NH)CO and of Sgr B2(N),
makes the definitive identification of this molecule challenging. We present
observational spectra, laboratory data, and models, and discuss our results in
the context of a possible molecular detection of urea.Comment: 38 pages, 9 Figures, accepted in the Astrophysical Journa
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
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
Neorealism and the Organization of American States (OAS): an examination of CARICOM rationality toward Venezuela and the United States
Since 2017, CARICOM member states have been divided in the positions they take on Organization of American States (OAS)
resolutions addressing political instability in Venezuela. This article uses a neorealism framework to determine whether or
not the provision of energy investments by Venezuela and the United States to CARICOM member countries is an attempt
on their part to skew the OAS voting mechanism in their national interests. The article also examines the extent to which
CARICOM member states’ response to Venezuela’s and United States’ interest in the OAS demonstrates a pattern of
rationality. The findings suggest that though the OAS provides a medium for states to negotiate mutually beneficial solutions,
states are rational actors and even where they do corporate, dominant states may try to manifest their self-interest
IRAS4A1: Multi-wavelength continuum analysis of a very flared Class 0 disk
Understanding the formation of substructures in protoplanetary disks is vital
for gaining insights into dust growth and the process of planet formation.
Studying these substructures in highly embedded Class 0 objects using the
Atacama Large Millimeter/submillimeter Array (ALMA), however, poses significant
challenges. Nonetheless, it is imperative to do so to unravel the mechanisms
and timing behind the formation of these substructures. In this study, we
present high-resolution ALMA data at Bands 6 and 4 of the NGC1333 IRAS4A Class
0 protobinary system. This system consists of two components, A1 and A2,
separated by 1.8" and located in the Perseus molecular cloud at 293 pc
distance. To gain a comprehensive understanding of the dust properties and
formation of substructures in the early stages, we conducted a multi-wavelength
analysis of IRAS4A1. Additionally, we sought to address whether the lack of
observed substructures in very young disks, could be attributed to factors such
as high degrees of disk flaring and large scale heights. To explore this
phenomenon, we employed radiative transfer models using RADMC-3D. Our
multi-wavelength analysis of A1 discovered characteristics such as high dust
surface density, substantial dust mass within the disk, and elevated dust
temperatures. These findings suggest the presence of large dust grains compared
to the ones in the interstellar medium (ISM), greater than 100 microns in size
within the region. Furthermore, while there's no direct detection of any
substructure, our models indicate that some, such as a small gap, must be
present. In summary, this result implies that disk substructures may be masked
or obscured by a large scale height in combination with a high degree of
flaring in Class 0 disks. [Abridged]Comment: Accepted for publication in A&A, 13 pages, 7 figure
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
TADPOL: A 1.3 mm Survey of Dust Polarization in Star-forming Cores and Regions
We present {\lambda}1.3 mm CARMA observations of dust polarization toward 30
star-forming cores and 8 star-forming regions from the TADPOL survey. We show
maps of all sources, and compare the ~2.5" resolution TADPOL maps with ~20"
resolution polarization maps from single-dish submillimeter telescopes. Here we
do not attempt to interpret the detailed B-field morphology of each object.
Rather, we use average B-field orientations to derive conclusions in a
statistical sense from the ensemble of sources, bearing in mind that these
average orientations can be quite uncertain. We discuss three main findings:
(1) A subset of the sources have consistent magnetic field (B-field)
orientations between large (~20") and small (~2.5") scales. Those same sources
also tend to have higher fractional polarizations than the sources with
inconsistent large-to-small-scale fields. We interpret this to mean that in at
least some cases B-fields play a role in regulating the infall of material all
the way down to the ~1000 AU scales of protostellar envelopes. (2) Outflows
appear to be randomly aligned with B-fields; although, in sources with low
polarization fractions there is a hint that outflows are preferentially
perpendicular to small-scale B-fields, which suggests that in these sources the
fields have been wrapped up by envelope rotation. (3) Finally, even at ~2.5"
resolution we see the so-called "polarization hole" effect, where the
fractional polarization drops significantly near the total intensity peak. All
data are publicly available in the electronic edition of this article.Comment: 53 pages, 37 figures -- main body (13 pp., 3 figures), source maps
(32 pp., 34 figures), source descriptions (8 pp.). Accepted by the
Astrophysical Journal Supplemen
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