1,960 research outputs found
Feed the crop or feed the soil? A case study in leek (Allium porrum L.)
The purpose of our study was to assess the role of soil quality parameters in leek production and to assess their importance relative to nitrogen (N) applied as fertilizer. We selected seven (2004) and seven (2005) fields on leek farms in the southern sand district of the Netherlands and measured physical and chemical soil properties. Three N rates (0, 90 and 360 kg N ha-1 as calcium ammonium nitrate; denoted as N0, N90, N360) were given at each site. Leek (Allium porrum L. ‘Kenton’) was planted in June-July and harvested next spring. Measured response variables were shoot biomass yield (gross and net, fresh and dry) and shoot N-yield (gross, net) at harvest. Pooled data from both years were analyzed by linear regression. N uptake from unfertilized soil (U0), and topsoil properties soluble organic N (Nso), soil organic matter content (SOM), total nitrogen (Ntot) and water content at field capacity (Wfc) all had large and significant impacts on biomass yield and N yield. These five properties (Xi) were correlated and were therefore used alternately in regression models. Effects of soil properties found by regression refer to a shift in the regressor from its 25% to its 75% percentile value, and are expressed here relative to mean yields (both years, all treatments). This normalization facilitates direct comparison with fertilizer effects. Normalized effects of Xi variables on biomass yield and N yield were between +0.10 and +0.20. Effects of fertilizer application at N90 were about +0.10 (biomass yield) and +0.20 (N yield). At N360 effects were +0.10 to +0.20 (biomass yield) and +0.30 to +0.40 (N-yield). So while N fertilizer strongly promoted N-uptake relative to growth, soil properties Xi affected growth and N yield more evenly. With shifts in Xi variables, dry matter produced per kg additional N uptake was 1.49 to 1.77 times larger than with extra N uptake resulting from fertilizer application at N90. This indicates that soil properties Xi promoted yield not only via enhanced N supply. Besides effects of Xi properties and N fertilizer, we found significant effects of year, soil texture, pH and inorganic soil N at planting, on biomass yield. Texture parameters Fsfine (50-210 µm) and M50 (median of particle size in 50-2000 µm fraction) had large and additive positive effects on net fresh yield. Apparent recovery of fertilizer N (ANR) averaged 0.35 at N90, and 0.17 at N360. ANR decreased with higher Nso and increased with higher Wfc
A note on the forced Burgers equation
We obtain the exact solution for the Burgers equation with a time dependent
forcing, which depends linearly on the spatial coordinate. For the case of a
stochastic time dependence an exact expression for the joint probability
distribution for the velocity fields at multiple spatial points is obtained. A
connection with stretched vortices in hydrodynamic flows is discussed.Comment: 10 page
Anisotropic Improved Gauge Actions; --Perturbative and Numerical Studies --
The parameter on the anisotropic lattice, the spatial and
temperature coupling constant , and their derivative
with respaect to the the anisotropy parameter are studied perturbatively
for the class of improved actions, which cover tree level Symanzik's, Iwasaki's
and QCDTARO's improved actions. The becomes less
than 1 for Iwasaki's and QCDTARO's action, which is confirmed nonperturbatively
by numerical simulations. Derivatives of the coupling constants with respect to
the anisotropy parameter, and , change sign for those improved actions.Comment: LATTICE98(hightemp), 3 pages in latex, 4 Postscript figures Fonts in
Fig3 is replaced Aria
Climate scenarios of sea level rise for the northeast Atlantic Ocean: a study including the effects of ocean dynamics and gravity changes induced by ice melt
Here we present a set of regional climate scenarios of sea level rise for the northeast Atlantic Ocean. In this study, the latest observations and results obtained with state-of-the-art climate models are combined. In addition, regional effects due to ocean dynamics and changes in the Earth’s gravity field induced by melting of land-based ice masses have been taken into account. The climate scenarios are constructed for the target years 2050 and 2100, for both a moderate and a large rise in global mean atmospheric temperature (2 °C and 4 °C in 2100 respectively). The climate scenarios contain contributions from changes in ocean density (global thermal expansion and local steric changes related to changing ocean dynamics) and changes in ocean mass (melting of mountain glaciers and ice caps, changes in the Greenland and Antarctic ice sheets, and (minor) terrestrial water-storage contributions). All major components depend on the global temperature rise achieved in the target periods considered. The resulting set of climate scenarios represents our best estimate of twenty-first century sea level rise in the northeast Atlantic Ocean, given the current understanding of the various contributions. For 2100, they yield a local rise of 30 to 55 cm and 40 to 80 cm for the moderate and large rise in global mean atmospheric temperature, respectively. <br/
Generation of frequency sidebands on single photons with indistinguishability from quantum dots
Generation and manipulation of the quantum state of a single photon is at the
heart of many quantum information protocols. There has been growing interest in
using phase modulators as quantum optics devices that preserve coherence. In
this Letter, we have used an electro-optic phase modulator to shape the state
vector of single photons emitted by a quantum dot to generate new frequency
components (modes) and explicitly demonstrate that the phase modulation process
agrees with the theoretical prediction at a single photon level. Through
two-photon interference measurements we show that for an output consisting of
three modes (the original mode and two sidebands), the indistinguishability of
the mode engineered photon, measured through the secondorder intensity
correlation (g2(0)) is preserved. This work demonstrates a robust means to
generate a photonic qubit or more complex state (e.g., a qutrit) for quantum
communication applications by encoding information in the sidebands without the
loss of coherence
Prosodic markers of satirical imitation
Satirical imitation is a popular format of late-night comedy shows and can provide political entertainment and education. However, little research has been conducted on how satirists mark their satirical intent to clue audiences in on their intended messaging. This study investigates the prosodic marking of satirical imitation and contrasts it with prosodic marking of irony. We conducted a detailed case study of the prosodic marking in Alec Baldwin's satirical imitation of Donald Trump in his audiobook You Can't Spell America Without Me contrasted with both Baldwin's and Trump's regular voices. The analyzed corpus contained six hours of audio material across the three sources. Through a combination of automatic and manual coding, we measured average pitch, pitch variation, and speech rate. Our analysis did not reveal marking of satirical imitation by pitch or pitch variation. The satirical imitation was only marked by a faster speech rate than both baseline voices. These findings contrast with previous studies that identified a lower pitch, less pitch variation, and a slower speech rate as markers of verbal irony. Our study provides first evidence that satirical imitation is prosodically marked differently from verbal irony, with a faster speech rate as one potential marker
Non-perturbative determination of anisotropy coefficients and pressure gap at the deconfining transition of QCD
We propose a new non-perturbative method to compute derivatives of gauge
coupling constants with respect to anisotropic lattice spacings (anisotropy
coefficients). Our method is based on a precise measurement of the finite
temperature deconfining transition curve in the lattice coupling parameter
space extended to anisotropic lattices by applying the spectral density method.
We determine the anisotropy coefficients for the cases of SU(2) and SU(3) gauge
theories. A longstanding problem, when one uses the perturbative anisotropy
coefficients, is a non-vanishing pressure gap at the deconfining transition
point in the SU(3) gauge theory. Using our non-perturbative anisotropy
coefficients, we find that this problem is completely resolved.Comment: LATTICE98(hightemp
Clocked Atom Delivery to a Photonic Crystal Waveguide
Experiments and numerical simulations are described that develop quantitative
understanding of atomic motion near the surfaces of nanoscopic photonic crystal
waveguides (PCWs). Ultracold atoms are delivered from a moving optical lattice
into the PCW. Synchronous with the moving lattice, transmission spectra for a
guided-mode probe field are recorded as functions of lattice transport time and
frequency detuning of the probe beam. By way of measurements such as these, we
have been able to validate quantitatively our numerical simulations, which are
based upon detailed understanding of atomic trajectories that pass around and
through nanoscopic regions of the PCW under the influence of optical and
surface forces. The resolution for mapping atomic motion is roughly 50 nm in
space and 100 ns in time. By introducing auxiliary guided mode (GM) fields that
provide spatially varying AC-Stark shifts, we have, to some degree, begun to
control atomic trajectories, such as to enhance the flux into to the central
vacuum gap of the PCW at predetermined times and with known AC-Stark shifts.
Applications of these capabilities include enabling high fractional filling of
optical trap sites within PCWs, calibration of optical fields within PCWs, and
utilization of the time-dependent, optically dense atomic medium for novel
nonlinear optical experiments
Practising person-centred care. Selected abstracts from the virtual 26th WONCA Europe conference, 6-10 July 2021
BACKGROUND: From 6 to 10 July 2021, WONCA Europe and the Dutch College of General Practitioners as host organiser welcomed 1,266 family physicians/general practitioners, teachers, researchers, and students from 66 countries interested in sharing knowledge, experience and innovations in primary healthcare. METHODS: In cohesive sets of plenary presentations, round table sessions, and research masterclasses, aspects of patient care, research, and education around Practicing Person-Centred Care were presented and discussed. Actual topics in primary care such as covid-19, e-health and professional health, were covered in oral presentation sessions, one slide 5-minutes presentations, case presentations by young doctors and the e-poster gallery. All sessions were recorded and available on-demand for registrants until three months after the conference. All accepted abstracts have been published in the abstract book [https://www.woncaeurope.org/page/past-conference-abstract-books]. For this Journal, we selected the top 20 abstracts based on reviewers scores (mean of 3.5 or higher on a scale of 4) and consensus among members of the Scientific Committee. RESULTS: The selected abstracts are divided into the following themes: (1) clinical topics often encountered in primary care, such as acute chest pain, urinary tract infections, dementia, and covid-19 (N = 5); (2) personalised care and related issues such as addressing multimorbidity (N = 2); shared decision making and patient empowerment (N = 4); (3) overdiagnosis and overtreatment, focusing on deprescribing (N = 2); (4) health promotion and prevention, including mental health (N = 2); (5) quality and safety (N = 2); (6) professional development and education (N = 1); (7) research and innovation, including teleconsultation (N = 2)
Clinical practice guidelines: towards better quality guidelines and increased international collaboration
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