210 research outputs found
A study of two seed-borne Alternaria diseases on choumoellier : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University
The livestock industry in New Zealand is based on a pastoral farming economy, an important aspect of which is the utilisation of fodder crops as supplementary feed during seasons of poor pasture growth. Playing an important role in this regard are the two selections of choumoellier
(Brassica oleracea var. acephala D.C.) usually referred to as giant choumoellier and medium stemmed choumoellier.
The growing importance of choumoellier in feed crop rotations is indicated by the increased area sown, from 8,000 acres in 1933 to 130,000 acres in 1963 (New Zealand Farm Production Statistics, 1962-63). In the past, choumoellier seed has been imported from the United Kingdom, but more recently
the trend has been to promote locally grown seed. At the present time New Zealand's requirements are met in most years by South Island growers producing seed under the authority of a Government seed certification scheme.
In discussing brassica crops in New Zealand, Palmer (1966) stated that - "apart from weather variations, the main
uncontrollable causes of yield variations are fungus diseases, insect pests and associated virus diseases''• Seven fungus
diseases are recorded in
New Zealand on choumoellier (Table 1),
five of which are evidenced by foliage lesioning in field stands
Plasma Wakefield Acceleration with a Modulated Proton Bunch
The plasma wakefield amplitudes which could be achieved via the modulation of
a long proton bunch are investigated. We find that in the limit of long bunches
compared to the plasma wavelength, the strength of the accelerating fields is
directly proportional to the number of particles in the drive bunch and
inversely proportional to the square of the transverse bunch size. The scaling
laws were tested and verified in detailed simulations using parameters of
existing proton accelerators, and large electric fields were achieved, reaching
1 GV/m for LHC bunches. Energy gains for test electrons beyond 6 TeV were found
in this case.Comment: 9 pages, 7 figure
All-optical switching and strong coupling using tunable whispering-gallery-mode microresonators
We review our recent work on tunable, ultrahigh quality factor
whispering-gallery-mode bottle microresonators and highlight their applications
in nonlinear optics and in quantum optics experiments. Our resonators combine
ultra-high quality factors of up to Q = 3.6 \times 10^8, a small mode volume,
and near-lossless fiber coupling, with a simple and customizable mode structure
enabling full tunability. We study, theoretically and experimentally, nonlinear
all-optical switching via the Kerr effect when the resonator is operated in an
add-drop configuration. This allows us to optically route a single-wavelength
cw optical signal between two fiber ports with high efficiency. Finally, we
report on progress towards strong coupling of single rubidium atoms to an
ultra-high Q mode of an actively stabilized bottle microresonator.Comment: 20 pages, 24 figures. Accepted for publication in Applied Physics B.
Changes according to referee suggestions: minor corrections to some figures
and captions, clarification of some points in the text, added references,
added new paragraph with results on atom-resonator interactio
Wind modelling of very massive stars up to 300 solar masses
Some studies have claimed a universal stellar upper-mass limit of 150 Msun. A
factor that is often overlooked is that there might be a difference between the
current and initial masses of the most massive stars, as a result of mass loss.
We present Monte Carlo mass-loss predictions for very massive stars in the
range 40-300 Msun, with large luminosities and Eddington factors Gamma. Using
our new dynamical approach, we find an upturn in the mass-loss vs. Gamma
dependence, at the point where the winds become optically thick. This coincides
with the location where wind efficiency numbers surpass the single-scattering
limit of Eta = 1, reaching values up to Eta = 2.5. Our modelling suggests a
transition from common O-type winds to Wolf-Rayet characteristics at the point
where the winds become optically thick. This transitional behaviour is also
revealed with respect to the wind acceleration parameter beta, which starts at
values below 1 for the optically thin O-stars, and naturally reaches values as
high as 1.5-2 for the optically thick Wolf-Rayet models. An additional finding
concerns the transition in spectral morphology of the Of and WN characteristic
He II line at 4686 Angstrom. When we express our mass-loss predictions as a
function of the electron scattering Gamma_e (=L/M) only, we obtain a mass-loss
Gamma dependence that is consistent with a previously reported power-law Mdot
propto Gamma^5 (Vink 2006) that was based on our semi-empirical modelling
approach. When we express Mdot in terms of both Gamma and stellar mass, we find
Mdot propto M^0.8 Gamma^4.8 for our high Gamma models. Finally, we confirm that
the Gamma-effect on the mass-loss predictions is much stronger than that of an
increased helium abundance, calling for a fundamental revision in the way mass
loss is incorporated in evolutionary models of the most massive stars.Comment: minor language changes (Astronomy & Astrophysics in press - 11 pages,
10 figures
Optimal measurements for simultaneous quantum estimation of multiple phases
A quantum theory of multiphase estimation is crucial for quantum-enhanced
sensing and imaging and may link quantum metrology to more complex quantum
computation and communication protocols. In this letter we tackle one of the
key difficulties of multiphase estimation: obtaining a measurement which
saturates the fundamental sensitivity bounds. We derive necessary and
sufficient conditions for projective measurements acting on pure states to
saturate the maximal theoretical bound on precision given by the quantum Fisher
information matrix. We apply our theory to the specific example of
interferometric phase estimation using photon number measurements, a convenient
choice in the laboratory. Our results thus introduce concepts and methods
relevant to the future theoretical and experimental development of
multiparameter estimation.Comment: 4 pages + appendix, 2 figure
Non-identical particle correlations in 130 and 200 AGeV collisions at STAR
STAR has performed a correlation analyses of pion-kaon and pion-proton pairs
for sqrt(s_NN)=130 AGeV and sqrt(s_NN)=200 AGeV and kaon-proton, proton-Lambda
and pion-Cascade pairs for AuAu collisions sqrt(s_NN)=200 AGeV. They show that
average emission space-time points of pions, kaons and protons are not the
same. These asymmetries are interpreted as a consequence of transverse radial
expansion of the system; emission time differences explain only part of the
asymmetry. Therefore our measurements independently confirm the existence of
transverse radial flow. Furthermore, correlations of strange hyperons is
investigated by performing proton-Lambda and pion-Cascade analyses, giving
estimates of source size at high m_{T}. The strong interaction potential
between (anti-)proton and lambda as well as kaon and proton is investigated.Comment: 5 pages, 3 figures, Quark Matter 04 proceedings, submitted to J.
Phys. G: Nucl. Phy
Genome-wide analysis identifies 12 loci influencing human reproductive behavior.
The genetic architecture of human reproductive behavior-age at first birth (AFB) and number of children ever born (NEB)-has a strong relationship with fitness, human development, infertility and risk of neuropsychiatric disorders. However, very few genetic loci have been identified, and the underlying mechanisms of AFB and NEB are poorly understood. We report a large genome-wide association study of both sexes including 251,151 individuals for AFB and 343,072 individuals for NEB. We identified 12 independent loci that are significantly associated with AFB and/or NEB in a SNP-based genome-wide association study and 4 additional loci associated in a gene-based effort. These loci harbor genes that are likely to have a role, either directly or by affecting non-local gene expression, in human reproduction and infertility, thereby increasing understanding of these complex traits
Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study
Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised
- …