1,112 research outputs found
Alfalfa mosaic virus: Occurrence and variation among isolates from forage legumes in Ethiopia
Filed samples and seedlings of 51 leguminous forage species were tested for alfalfa mosaic virus (AMV) in routine monitoring of seed multiplication fields of the International Livestock Research Institute (ILRI), Ethiopia. The virus was detected in 24 species and a solanaceous weed Solanum nigrum. Of these, the following 17 species are being reported for the first time as hosts of the virus in world literature: Aeschynomene falcata, Centrosema pascuorum, Chamaecrista rotundifolia, Desmanthus virgatus, Desmodium intortum, Leucaena leucocephala, Macroptilium atropurpureum, Macroptilium lathyroides, Macrotyloma axillare, Medicago truncatula, Neonotonia wightii, Sesbania sesban, Stylosanthes scabra, Trifolium calocephala, T. steudneri, T. tembense and Vigna parkeri. The solanaceous weed S. nigrum was suspected to play a role in the virus epidemiology. The level of seed infection varied from 0.00 percent to about 13.00 percent. Infectivity studies on 5 isolates of the virus revealed heterogeneity in prevalent AMV isolates. Two major strains were identified, based on the development of necrotic local lesions on Vigna unguiculata accessions. One of the isolates which failed to incite local necrotic lesions on unguiculata infected Phaseolus vulgaris cTop Crop systematically. Differences among isolates were also noticed in their concentration in different hosts as indicated by ELISA absorbance values
Responses of vascular plant fine roots and associated microbial communities to whole-ecosystem warming and elevated CO2 in northern peatlands
Warming and elevated CO2 (eCO2) are expected to facilitate vascular plant encroachment in peatlands. The rhizosphere, where microbial activity is fueled by root turnover and exudates, plays a crucial role in biogeochemical cycling, and will likely at least partially dictate the response of the belowground carbon cycle to climate changes. We leveraged the Spruce and Peatland Responses Under Changing Environments (SPRUCE) experiment, to explore the effects of a whole-ecosystem warming gradient (+0°C to 9°C) and eCO2 on vascular plant fine roots and their associated microbes. We combined trait-based approaches with the profiling of fungal and prokaryote communities in plant roots and rhizospheres, through amplicon sequencing. Warming promoted self-reliance for resource uptake in trees and shrubs, while saprophytic fungi and putative chemoorganoheterotrophic bacteria utilizing plant-derived carbon substrates were favored in the root zone. Conversely, eCO2 promoted associations between trees and ectomycorrhizal fungi. Trees mostly associated with short-distance exploration-type fungi that preferentially use labile soil N. Additionally, eCO2 decreased the relative abundance of saprotrophs in tree roots. Our results indicate that plant fine-root trait variation is a crucial mechanism through which vascular plants in peatlands respond to climate change via their influence on microbial communities that regulate biogeochemical cycles
Healthcare satisfaction in older and younger patients with cancer
Objective Although older patients represent the most rapidly growing segment of the oncology population, clinical care is guided by very little data on patient-reported outcomes, particularly satisfaction with healthcare. Using a large cancer center registry, we sought to describe factors associated with satisfaction with care for older and younger oncology patients. Methods Data were collected through the University of North Carolina Health Registry Cancer Survivorship Cohort. Satisfaction was measured with the Patient Satisfaction Questionnaire Short Form. Quality of life (QOL) measures included were the Promis Global short form and the Functional Assessment of Cancer Therapy General (FACT-G). Results A total of 2385 patients were included. 460 (20%) were aged 70 and above (older group). Older patients reported significantly higher levels of satisfaction in domains of time spent with doctor (scores 3.84 versus 3.73 p = 0.03) and financial aspects (scores 4.03 versus 3.44 p < 0.001) compared to younger patients. In multivariable analysis, higher QOL scores and higher self-reported ECOG performance status were associated with higher satisfaction scores. African American race was associated with lower satisfaction scores in all age groups. QOL was more closely correlated with satisfaction in older patients compared to younger patients. Conclusions Older patients with cancer report higher levels of satisfaction with care, in part due to lesser financial burden of care. Better QOL is associated with satisfaction with care in older patients. Use of patient-reported outcomes such as patient satisfaction may help improve patient-centered geriatric oncology care
On Verification of the Non-Generational Conjectural- Derivation of First Class constraints: HP Monopole's Field case
In [7] we proposed a non-generational conjectural derivation of all first
class constraints (involving, only, variables compatible with canonical Poisson
brackets) for realistic gauge (singular) field theories; and we verified the
conjecture in cases of electromagnetic field, Yang Mills fields interacting
with scalar and spinor fields, and the gravitational field. Here we will
further verify our conjecture for the case of 't Hooft- Polyakov (HP)
monopole's field (i.e. in the Higgs Vacuum); and show that we will reproduce
the results in Ref.[6], which we reached at using Dirac's standard
multi-generational algorithm
Surveillance of Influenza Virus A in Migratory Waterfowl in Northern Europe
Ducks may maintain influenza virus from 1 year to the next
On the covariant quantization of tensionless bosonic strings in AdS spacetime
The covariant quantization of the tensionless free bosonic (open and closed)
strings in AdS spaces is obtained. This is done by representing the AdS space
as an hyperboloid in a flat auxiliary space and by studying the resulting
string constrained hamiltonian system in the tensionless limit. It turns out
that the constraint algebra simplifies in the tensionless case in such a way
that the closed BRST quantization can be formulated and the theory admits then
an explicit covariant quantization scheme. This holds for any value of the
dimension of the AdS space.Comment: 1+16 pages; v4 two clarifications adde
Detecting a stochastic gravitational wave background with the Laser Interferometer Space Antenna
The random superposition of many weak sources will produce a stochastic
background of gravitational waves that may dominate the response of the LISA
(Laser Interferometer Space Antenna) gravitational wave observatory. Unless
something can be done to distinguish between a stochastic background and
detector noise, the two will combine to form an effective noise floor for the
detector. Two methods have been proposed to solve this problem. The first is to
cross-correlate the output of two independent interferometers. The second is an
ingenious scheme for monitoring the instrument noise by operating LISA as a
Sagnac interferometer. Here we derive the optimal orbital alignment for
cross-correlating a pair of LISA detectors, and provide the first analytic
derivation of the Sagnac sensitivity curve.Comment: 9 pages, 11 figures. Significant changes to the noise estimate
The Hamiltonian formulation of General Relativity: myths and reality
A conventional wisdom often perpetuated in the literature states that: (i) a
3+1 decomposition of space-time into space and time is synonymous with the
canonical treatment and this decomposition is essential for any Hamiltonian
formulation of General Relativity (GR); (ii) the canonical treatment
unavoidably breaks the symmetry between space and time in GR and the resulting
algebra of constraints is not the algebra of four-dimensional diffeomorphism;
(iii) according to some authors this algebra allows one to derive only spatial
diffeomorphism or, according to others, a specific field-dependent and
non-covariant four-dimensional diffeomorphism; (iv) the analyses of Dirac
[Proc. Roy. Soc. A 246 (1958) 333] and of ADM [Arnowitt, Deser and Misner, in
"Gravitation: An Introduction to Current Research" (1962) 227] of the canonical
structure of GR are equivalent. We provide some general reasons why these
statements should be questioned. Points (i-iii) have been shown to be incorrect
in [Kiriushcheva et al., Phys. Lett. A 372 (2008) 5101] and now we thoroughly
re-examine all steps of the Dirac Hamiltonian formulation of GR. We show that
points (i-iii) above cannot be attributed to the Dirac Hamiltonian formulation
of GR. We also demonstrate that ADM and Dirac formulations are related by a
transformation of phase-space variables from the metric to lapse
and shift functions and the three-metric , which is not canonical. This
proves that point (iv) is incorrect. Points (i-iii) are mere consequences of
using a non-canonical change of variables and are not an intrinsic property of
either the Hamilton-Dirac approach to constrained systems or Einstein's theory
itself.Comment: References are added and updated, Introduction is extended,
Subsection 3.5 is added, 83 pages; corresponds to the published versio
Rickettsial Infection in Animals and Brazilian Spotted Fever Endemicity
Surveys of horse serum are a useful method of surveillance for Brazilian spotted fever in areas where humans are exposed to Amblyomma cajennense ticks
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