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Alfalfa Pollination in Arizona: A Progress Report
This item is part of the Agricultural Experiment Station archive. It was digitized from a physical copy provided by the University Libraries at the University of Arizona. For more information, please email CALS Publications at [email protected]
Radiative transport analysis of electromagnetic propagation in isotropic plasma turbulence
The problem of electromagnetic wave propagation in a turbulent plasma is formulated in terms of the radiative transport equation. A singular eigenfunction solution is obtained for the case of isotropic plasma turbulence, and detailed numerical calculations are presented. The intensity distribution is studied as a function of the turbulent spectrum and relative strength of scattering attenuation to total attenuation. For a highly forward peaked scattering law characteristic of many physical situations it is found that the reflected backscatter intensity is relatively insensitive to the angle of incidence, except as grazing incidence is approached. The importance of multiple scatter is studied as a function of the properties of the medium
Critique of a Pion Exchange Model for Interquark Forces
I describe four serious defects of a widely discussed pion exchange model for
interquark forces: it doesn't solve the "spin-orbit problem" as advertised, it
fails to describe the internal structure of baryon resonances, it leads to
disastrous conclusions when extended to mesons, and it is not reasonably
connected to the physics of heavy-light systems.Comment: 20 pages, 6 figures; some clarifications and references adde
Properties of Light Flavour Baryons in Hypercentral quark model
The light flavour baryons are studied within the quark model using the hyper
central description of the three-body system. The confinement potential is
assumed as hypercentral coulomb plus power potential () with power
index . The masses and magnetic moments of light flavour baryons are
computed for different power index, starting from 0.5 to 1.5. The
predicted masses and magnetic moments are found to attain a saturated value
with respect to variation in beyond the power index 1.0. Further
we computed transition magnetic moments and radiative decay width of light
flavour baryons. The results are in good agreement with known experimental as
well as other theoretical models.Comment: Accepted in Pramana J. of Physic
The central engine of GRB 130831A and the energy breakdown of a relativistic explosion
Gamma-ray bursts (GRBs) are the most luminous explosions in the universe, yet
the nature and physical properties of their energy sources are far from
understood. Very important clues, however, can be inferred by studying the
afterglows of these events. We present optical and X-ray observations of GRB
130831A obtained by Swift, Chandra, Skynet, RATIR, Maidanak, ISON, NOT, LT and
GTC. This burst shows a steep drop in the X-ray light-curve at s
after the trigger, with a power-law decay index of . Such a rare
behaviour cannot be explained by the standard forward shock (FS) model and
indicates that the emission, up to the fast decay at s, must be of
"internal origin", produced by a dissipation process within an
ultrarelativistic outflow. We propose that the source of such an outflow, which
must produce the X-ray flux for day in the cosmological rest frame,
is a newly born magnetar or black hole. After the drop, the faint X-ray
afterglow continues with a much shallower decay. The optical emission, on the
other hand, shows no break across the X-ray steep decrease, and the late-time
decays of both the X-ray and optical are consistent. Using both the X-ray and
optical data, we show that the emission after s can be explained
well by the FS model. We model our data to derive the kinetic energy of the
ejecta and thus measure the efficiency of the central engine of a GRB with
emission of internal origin visible for a long time. Furthermore, we break down
the energy budget of this GRB into the prompt emission, the late internal
dissipation, the kinetic energy of the relativistic ejecta, and compare it with
the energy of the associated supernova, SN 2013fu.Comment: Accepted for publication by MNRAS. 21 pages, 3 figures, 8 tables.
Extra table with magnitudes in the sourc
Tomboys and girly-girls: embodied femininities in primary schools
This paper is about how nine to eleven year old children, particularly girls, co-construct tomboy and girly-girl identities as oppositional positions. The paper sits within a theoretical framework in which I understand individual and collective masculinities and femininities as ways of âdoing man/womanâ or âdoing boy/girlâ that are constructed within local communities of masculinity and femininity practice. Empirical data come from a one-year study of tomboy identities within two London primary schools. The paper explores the contrasting identities of tomboy and girly-girl, how they are constructed by the children, and how this changes as they approach puberty. The findings suggest that the oppositional construction of these identities makes it harder for girls to take up more flexible femininities, though it is possible to switch between tomboy and girly-girl identities at different times and places
A Global Ecological Classification of Coastal Segment Units to Complement Marine Biodiversity Observation Network Assessments
A new data layer provides Coastal and Marine Ecological Classification Standard (CMECS) labels for global coastal segments at 1 km or shorter resolution. These characteristics are summarized for six US Marine Biodiversity Observation Network (MBON) sites and one MBON Pole to Pole of the Americas site in Argentina. The global coastlines CMECS classifications were produced from a partitioning of a 30 m Landsat-derived shoreline vector that was segmented into 4 million 1 km or shorter segments. Each segment was attributed with values from 10 variables that represent the ecological settings in which the coastline occurs, including properties of the adjacent water, adjacent land, and coastline itself. The 4 million segments were classified into 81,000 coastal segment units (CSUs) as unique combinations of variable classes. We summarize the process to develop the CSUs and derive summary descriptions for the seven MBON case study sites. We discuss the intended application of the new CSU data for research and management in coastal areas
Clinical and Research Considerations for Patients with Hypertensive Acute Heart Failure
Management approaches for patients in the emergency department (ED) who present with acute heart failure (AHF) have largely focused on intravenous diuretics. Yet, the primary pathophysiologic derangement underlying AHF in many patients is not solely volume overload. Patients with hypertensive AHF (H-AHF) represent a clinical phenotype with distinct pathophysiologic mechanisms that result in elevated ventricular filling pressures. To optimize treatment response and minimize adverse events in this subgroup, we propose that clinical management be tailored to a conceptual model of disease based on these mechanisms. This consensus statement reviews the relevant pathophysiology, clinical characteristics, approach to therapy, and considerations for clinical trials in ED patients with H-AHF
Improved Standardization of Type II-P Supernovae: Application to an Expanded Sample
In the epoch of precise and accurate cosmology, cross-confirmation using a
variety of cosmographic methods is paramount to circumvent systematic
uncertainties. Owing to progenitor histories and explosion physics differing
from those of Type Ia SNe (SNe Ia), Type II-plateau supernovae (SNe II-P) are
unlikely to be affected by evolution in the same way. Based on a new analysis
of 17 SNe II-P, and on an improved methodology, we find that SNe II-P are good
standardizable candles, almost comparable to SNe Ia. We derive a tight Hubble
diagram with a dispersion of 10% in distance, using the simple correlation
between luminosity and photospheric velocity introduced by Hamuy & Pinto 2002.
We show that the descendent method of Nugent et al. 2006 can be further
simplified and that the correction for dust extinction has low statistical
impact. We find that our SN sample favors, on average, a very steep dust law
with total to selective extinction R_V<2. Such an extinction law has been
recently inferred for many SNe Ia. Our results indicate that a distance
measurement can be obtained with a single spectrum of a SN II-P during the
plateau phase combined with sparse photometric measurements.Comment: ApJ accepted version. Minor change
The coronal line regions of planetary nebulae NGC6302 and NGC6537: 3-13um grating and echelle spectroscopy
We report on advances in the study of the cores of NGC6302 and NGC6537 using
infrared grating and echelle spectroscopy. In NGC6302, emission lines from
species spanning a large range of ionization potential, and in particular
[SiIX]3.934um, are interpreted using photoionization models (including CLOUDY),
which allow us to reestimate the central star's temperature to be about
250000K. All of the detected lines are consistent with this value, except for
[AlV] and [AlVI]. Aluminium is found to be depleted to one hundredth of the
solar abundance, which provides further evidence for some dust being mixed with
the highly ionized gas (with photons harder than 154eV). A similar depletion
pattern is observed in NGC6537. Echelle spectroscopy of IR coronal ions in
NGC6302 reveals a stratified structure in ionization potential, which confirms
photoionization to be the dominant ionization mechanism. The lines are narrow
(< 22km/s FWHM), with no evidence of the broad wings found in optical lines
from species with similar ionization potentials, such as [NeV]3426A. We note
the absence of a hot bubble, or a wind blown bipolar cavity filled with a hot
plasma, at least on 1'' and 10km/s scales. We also provide accurate new
wavelengths for several of the infrared coronal lines observed with the
echelle.Comment: Accepted for publication in MNRA
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