2,404 research outputs found
Distribution of specific antibody activity among serum immunoglobulin isotypes following bovine herpesvirus I infection of cattle
The kinetics of antibody formation in Holstein-Friesan heifers following primary and secondary intranasal inoculation of bovine herpesvirus I (BHVI), reactivation of latent BHVl (RLI), and BHVI-induced abortion was determined. Sera were fractionated by gel filtration and ion exchange chromatography. The antibody activity within serum immunoglobulin isotypes was assessed by a virus plaque reduction assay (PRA).
The primary immune response to BHVl infection was characterized by the appearance of IgM and IgG antibodies in serum 7 days post inoculation (pi). Maximal IgG antibody activity occurred at 35 day pi in nonpregnant heifers and 14 days pi in pregnant heifers. Thereafter antibody activity in this class slowly declined. Maximal IgM antibody activity occurred at 14 days pi in both groups of heifers and declined rapidly thereafter. The IgG antibody activity during primary immune responses was localized to the IgG1 subclass primarily.
Secondary responses were characterized by anamnestic IgG antibody responses. Secondary IgM antibody formation was elicited by abortion induced by the intraamniotic inoculation of BHVI and RLI, but not by reexposure by the intranasal route. Antibody activity was present within both IgG subclasses during secondary immune responses. However, the increase in antibody activity during this period was in the IgG2 subclass primarily.
Abortion occurred in one heifer 28 days after intranasal BHVI inoculation. Abortion in this animal failed to stimulate a secondary antibody response.
The nature of BHVI antigenic exposure in the bovine was determined by assessing the relative distribution of anti-BHVI antibody activity among the serum immunoglobulin isotypes, IgM, IgGl, and IgG2. The formation of IgM antibody, with the exception of secondary intranasal exposure, indicated recent BHVI antigenic exposure. Primary immune responses were differentiated from secondary immune responses by the presence of IgGl antibody and the absence of IgG2 antibody
Determination of the critical current density in the d-wave superconductor YBCO under applied magnetic fields by nodal tunneling
We have studied nodal tunneling into YBa2Cu3O7-x (YBCO) films under magnetic
fields. The films' orientation was such that the CuO2 planes were perpendicular
to the surface with the a and b axis at 450 form the normal. The magnetic field
was applied parallel to the surface and perpendicular to the CuO2 planes. The
Zero Bias Conductance Peak (ZBCP) characteristic of nodal tunneling splits
under the effect of surface currents produced by the applied fields. Measuring
this splitting under different field conditions, zero field cooled and field
cooled, reveals that these currents have different origins. By comparing the
field cooled ZBCP splitting to that taken in decreasing fields we deduce a
value of the Bean critical current superfluid velocity, and calculate a Bean
critical current density of up to 3*10^7 A/cm2 at low temperatures. This
tunneling method for the determination of critical currents under magnetic
fields has serious advantages over the conventional one, as it avoids having to
make high current contacts to the sample.Comment: 8 pages, 2 figure
X-ray Spectral Analysis of the Steady States of GRS 1915+105
We report on the X-ray spectral behavior within the steady states of GRS
1915+105. Our work is based on the full data set on the source obtained using
the Proportional Counter Array on the Rossi X-ray Timing Explorer and 15 GHz
radio data obtained using the Ryle Telescope. The steady observations within
the X-ray data set naturally separated into two regions in the color-color
diagram and we refer to them as steady-soft and steady-hard. GRS 1915+105
displays significant curvature in the coronal component in both the soft and
hard data within the {\it RXTE}/PCA bandpass. A majority of the steady-soft
observations displays a roughly constant inner disk radius (R_in), while the
steady-hard observations display an evolving disk truncation which is
correlated to the mass accretion rate through the disk. The disk flux and
coronal flux are strongly correlated in steady-hard observations and very
weakly correlated in the steady-soft observations. Within the steady-hard
observations we observe two particular circumstances when there are
correlations between the coronal X-ray flux and the radio flux with log slopes
\eta~0.68 +/- 0.35 and \eta ~ 1.12 +/- 0.13. They are consistent with the upper
and lower tracks of Gallo et al. (2012), respectively. A comparison of model
parameters to the state definitions show that almost all steady-soft
observations match the criteria of either thermal or steep power law state,
while a large portion of the steady-hard observations match the hard state
criteria when the disk fraction constraint is neglected.Comment: 21 pages, 15 figures, 2 tables. Accepted for publication in Ap
Richness of IT Use Operationalization: A Conceptual Replication
Use of information technology (IT) remains a key concern for organizations. This article presents a conceptual replication of Burton-Jones and Straubâs (2006) study, exploring the effect of IT Use operationalization richness â lean and rich â on Performance. We used 352 valid responses from Amazon MTurk through an online survey. Consistent with the original study, the hypothesis was tested by using the Structural Equation Modeling technique. Our results â which indicated support for the same hypothesis in the original study â suggest that the richer the IT use operationalization, the higher the individual Performance
Ensetâbased agricultural systems in Ethiopia: A systematic review of production trends, agronomy, processing and the wider food security applications of a neglected banana relative
Enset (Ensete ventricosum (Welw.) Cheesman) is the major starch staple of the Ethiopian Highlands, where its unique attributes enhance the food security of approximately 20 million people and have earned it the title âThe Tree Against Hungerâ. Yet ensetâbased agriculture is virtually unknown outside of its narrow zone of cultivation, despite growing wild across much of East and Southern Africa. Here, we review historical production data to show that the area of land under enset production in Ethiopia has reportedly increased 46% in two decades, whilst yield increased 12âfold over the same period, making enset the second most produced crop species in Ethiopiaâthough we critically evaluate potential issues with these data. Furthermore, we address a major challenge in the development and wider cultivation of enset, by reviewing and synthesizing the complex and fragmented agronomic and ethnobotanic knowledge associated with this species; including farming systems, processing methods, products, medicinal uses and cultural importance. Finally, we provide a framework to improve the quality, consistency and comparability of data collected across culturally diverse ensetâbased agricultural systems to enhanced sustainable use of this neglected starch staple. In conclusion, we discuss the challenges and opportunities for enset cultivation beyond its restricted distribution, and the regional food security potential it could afford smallholders elsewhere in Southern and East Africa
Structural characteristics of positionally-disordered lattices: relation to the first sharp diffraction peak in glasses
Positional disorder has been introduced into the atomic structure of certain
crystalline lattices, and the orientationally-averaged structure factor S(k)
and pair-correlation function g(r) of these disordered lattices have been
studied. Analytical expressions for S(k) and g(r) for Gaussian positional
disorder in 2D and 3D are confirmed with precise numerical simulations. These
analytic results also have a bearing on the unsolved Gauss circle problem in
mathematics. As the positional disorder increases, high-k peaks in S(k) are
destroyed first, eventually leaving a single peak, that with the lowest-k
value. The pair-correlation function for lattices with such high levels of
positional disorder exhibits damped oscillations, with a period equal to the
separation between the furthest-separated (lowest-k) lattice planes. The last
surviving peak in S(k) is, for example for silicon and silica, at a wavevector
nearly identical to that of the experimentally-observed first sharp diffraction
peak (FSDP) in the amorphous phases of those materials. Thus, for these
amorphous materials at least, the FSDP can be regarded as arising from
scattering from atomic configurations equivalent to the single family of
positionally-disordered local Bragg planes having the furthest separation.Comment: v2: changes in response to referees' comments: Figure 2 made more
readable, improved discussion of height of peaks in S(k), other minor changes
4 pages, 3 figures, submitted to Physical Review
Type Ia supernova parameter estimation: a comparison of two approaches using current datasets
By using the Sloan Digital Sky Survey (SDSS) first year type Ia supernova (SN
Ia) compilation, we compare two different approaches (traditional \chi^2 and
complete likelihood) to determine parameter constraints when the magnitude
dispersion is to be estimated as well. We consider cosmological constant + Cold
Dark Matter (\Lambda CDM) and spatially flat, constant w Dark Energy + Cold
Dark Matter (FwCDM) cosmological models and show that, for current data, there
is a small difference in the best fit values and 30% difference in
confidence contour areas in case the MLCS2k2 light-curve fitter is adopted. For
the SALT2 light-curve fitter the differences are less significant (
13% difference in areas). In both cases the likelihood approach gives more
restrictive constraints. We argue for the importance of using the complete
likelihood instead of the \chi^2 approach when dealing with parameters in the
expression for the variance.Comment: 16 pages, 5 figures. More complete analysis by including peculiar
velocities and correlations among SALT2 parameters. Use of 2D contours
instead of 1D intervals for comparison. There can be now a significant
difference between the approaches, around 30% in contour area for MLCS2k2 and
up to 13% for SALT2. Generic streamlining of text and suppression of section
on model selectio
KOI-3890: A high mass-ratio asteroseismic red-giantM-dwarf eclipsing binary undergoing heartbeat tidal interactions
KOI-3890 is a highly eccentric, 153-day period eclipsing, single-lined
spectroscopic binary system containing a red-giant star showing solar-like
oscillations alongside tidal interactions. The combination of transit
photometry, radial velocity observations, and asteroseismology have enabled the
detailed characterisation of both the red-giant primary and the M-dwarf
companion, along with the tidal interaction and the geometry of the system. The
stellar parameters of the red-giant primary are determined through the use of
asteroseismology and grid-based modelling to give a mass and radius of
and
respectively. When combined with
transit photometry the M-dwarf companion is found to have a mass and radius of
and
. Moreover, through
asteroseismology we constrain the age of the system through the red-giant
primary to be . This provides a constraint on
the age of the M-dwarf secondary, which is difficult to do for other M-dwarf
binary systems. In addition, the asteroseismic analysis yields an estimate of
the inclination angle of the rotation axis of the red-giant star of
degrees. The obliquity of the system\textemdash the
angle between the stellar rotation axis and the angle normal to the orbital
plane\textemdash is also derived to give degrees
showing that the system is consistent with alignment. We observe no radius
inflation in the M-dwarf companion when compared to current low-mass stellar
models.Comment: 11 pages, 5 figures, accepted for publication in MNRA
Risk of tuberculosis cattle herd breakdowns in Ireland: effects of badger culling effort, density and historic large-scale interventions
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