169 research outputs found
Responses of onion growth and yield to different planting dates and land management practices
Received: September 10th, 2021 ; Accepted: November 3rd, 2021 ; Published: November 15th, 2021 ; Correspondence: [email protected] varieties of onion (Allium cepa L.) are believed to be well adopted to
agroecological conditions of their respective growing region but their lower productivity is a
concern to be addressed. The variety ‘Safid e Paisaye’ was selected for this investigation due to
its long storability and higher market demand. The present study was carried out at Agriculture
Research Farm of Kabul University to study the influence of land management practices and
planting dates on growth and yield of onion. Different agronomic traits including number of
leaves per plant, leaf length, leaf area per plant, leaf area index, normalized difference vegetation
index (NDVI), maturity period, marketable yield and total yield were studied in these trials. The
recorded data were statistically analysed with R software. The planting dates had significant
influence on growth and yield of onions. At 90 days after sowing, the highest number of leaves
per plant (7.18), leaf length (30.07 cm), leaf area per plant (277.43 cm2
), leaf area index (0.93)
and NDVI (0.29) were recorded for the first planting date (10th May). Similarly, the longest
maturity period (176.44 days) and highest marketable yield (37.01 t ha-1
) and total yield
(40.08 t ha-1
) were also observed under the first planting date. Land management practices did
not have significant effect on growth and maturity period of onions. However, the marketable
yield was influenced by tillage depth and land preparation. The deep tillage and flatbed recorded
highest marketable yield of 38.58 t ha-1
and 26.9 t ha-1
, respectively. The results of the study
indicate that, early planting was more appropriate to get vigorous and high yielding onions. The
deep ploughed flatbeds were appropriate to get higher marketable yield of onions
Path-following primal-dual interior-point methods for shape optimization of stationary flow problems
We consider shape optimization of Stokes flow in channels where the objective is to design the lateral walls of the channel in such a way that a desired velocity profile is achieved. This amounts to the solution of a PDE constrained optimization problem with the state equation given by the Stokes system and the design variables being the control points of a Bézier curve representation of the lateral walls subject to bilateral constraints. Using a finite element discretization of the problem by Taylor-Hood elements, the shape optimization problem is solved numerically by a path-following primal-dual interior-point method applied to the parameter dependent nonlinear system representing the optimality conditions. The method is an all-at-once approach featuring an adaptive choice of the continuation parameter, inexact Newton solves by means of right-transforming iterations, and a monotonicity test for convergence monitoring. The performance of the adaptive continuation process is illustrated by several numerical examples
How are soil use and management reflected by soil organic matter characteristics: a spectroscopic approach
We studied the quantitative and qualitative changes of soil organic matter (SOM) due to different land
uses (arable versus grassland) and treatments (organic manure and mineral fertilizer) within an agricultural crop rotation in a long-term field experiment, conducted since 1956 at Ultuna, Sweden, on a Eutric
Cambisol. The organic carbon (OC) content of the grassland plot was 1.8 times greater than that of the
similarly fertilized Ca(NO3)
2 treated cropped plots. The comparison of two dispersion techniques (a lowenergy sonication and a chemical dispersion which yield inherent soil aggregates) showed that increasing
OC contents of the silt-sized fractions were not matched by a linear increase of silt-sized aggregates. This
indicated saturation of the aggregates with OC and a limited capacity of particles to protect OC
physically. Thermogravimetric analyses suggested an increase of free organic matter with increasing
OC contents. Transmission FT-IR spectroscopy showed relative enrichment of carboxylic, aromatic,
CH and NH groups in plots with increasing OC contents. The silt-sized fractions contained the largest
SOM pool and, as revealed by 13C NMR spectroscopy, were qualitatively more influenced by the plant
residue versus manure input than the clay fractions. Alkyl and O-alkyl C in the silt-sized fractions
amounted to 57.4% of organic carbon in the animal manure treated plots and 50–53% in the other
treatments.We thank the Austrian Science Fund (Fonds zur FÖrderung
der wissenschaftlichen Forschung) for funding this bilateral
project.Peer reviewe
Model Order Reduction for Rotating Electrical Machines
The simulation of electric rotating machines is both computationally
expensive and memory intensive. To overcome these costs, model order reduction
techniques can be applied. The focus of this contribution is especially on
machines that contain non-symmetric components. These are usually introduced
during the mass production process and are modeled by small perturbations in
the geometry (e.g., eccentricity) or the material parameters. While model order
reduction for symmetric machines is clear and does not need special treatment,
the non-symmetric setting adds additional challenges. An adaptive strategy
based on proper orthogonal decomposition is developed to overcome these
difficulties. Equipped with an a posteriori error estimator the obtained
solution is certified. Numerical examples are presented to demonstrate the
effectiveness of the proposed method
Implementing health research through academic and clinical partnerships : a realistic evaluation of the Collaborations for Leadership in Applied Health Research and Care (CLAHRC)
Background: The English National Health Service has made a major investment in nine partnerships between
higher education institutions and local health services called Collaborations for Leadership in Applied Health
Research and Care (CLAHRC). They have been funded to increase capacity and capability to produce and
implement research through sustained interactions between academics and health services. CLAHRCs provide a
natural ‘test bed’ for exploring questions about research implementation within a partnership model of delivery.
This protocol describes an externally funded evaluation that focuses on implementation mechanisms and
processes within three CLAHRCs. It seeks to uncover what works, for whom, how, and in what circumstances.
Design and methods: This study is a longitudinal three-phase, multi-method realistic evaluation, which
deliberately aims to explore the boundaries around knowledge use in context. The evaluation funder wishes to see
it conducted for the process of learning, not for judging performance. The study is underpinned by a conceptual
framework that combines the Promoting Action on Research Implementation in Health Services and Knowledge to
Action frameworks to reflect the complexities of implementation. Three participating CLARHCS will provide indepth
comparative case studies of research implementation using multiple data collection methods including
interviews, observation, documents, and publicly available data to test and refine hypotheses over four rounds of
data collection. We will test the wider applicability of emerging findings with a wider community using an
interpretative forum.
Discussion: The idea that collaboration between academics and services might lead to more applicable health
research that is actually used in practice is theoretically and intuitively appealing; however the evidence for it is
limited. Our evaluation is designed to capture the processes and impacts of collaborative approaches for
implementing research, and therefore should contribute to the evidence base about an increasingly popular (e.g.,
Mode two, integrated knowledge transfer, interactive research), but poorly understood approach to knowledge
translation. Additionally we hope to develop approaches for evaluating implementation processes and impacts
particularly with respect to integrated stakeholder involvement
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