27 research outputs found
Converting simulated total dry matter to fresh marketable yield for field vegetables at a range of nitrogen supply levels
Simultaneous analysis of economic and environmental performance of horticultural crop production requires qualified assumptions on the effect of management options, and particularly of nitrogen (N) fertilisation, on the net returns of the farm. Dynamic soil-plant-environment simulation models for agro-ecosystems are frequently applied to predict crop yield, generally as dry matter per area, and the environmental impact of production. Economic analysis requires conversion of yields to fresh marketable weight, which is not easy to calculate for vegetables, since different species have different properties and special market requirements. Furthermore, the marketable part of many vegetables is dependent on N availability during growth, which may lead to complete crop failure under sub-optimal N supply in tightly calculated N fertiliser regimes or low-input systems. In this paper we present two methods for converting simulated total dry matter to marketable fresh matter yield for various vegetables and European growth conditions, taking into consideration the effect of N supply: (i) a regression based function for vegetables sold as bulk or bunching ware and (ii) a population approach for piecewise sold row crops. For both methods, to be used in the context of a dynamic simulation model, parameter values were compiled from a literature survey. Implemented in such a model, both algorithms were tested against experimental field data, yielding an Index of Agreement of 0.80 for the regression strategy and 0.90 for the population strategy. Furthermore, the population strategy was capable of reflecting rather well the effect of crop spacing on yield and the effect of N supply on product grading
Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications
Superparamagnetic iron oxide nanoparticles
can providemultiple benefits for biomedical applications
in aqueous environments such asmagnetic separation or
magnetic resonance imaging. To increase the colloidal
stability and allow subsequent reactions, the introduction
of hydrophilic functional groups onto the particles’
surface is essential. During this process, the original
coating is exchanged by preferably covalently bonded
ligands such as trialkoxysilanes. The duration of the
silane exchange reaction, which commonly takes more
than 24 h, is an important drawback for this approach. In
this paper, we present a novel method, which introduces
ultrasonication as an energy source to dramatically
accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove
the generic character, different functional groups were
introduced on the surface including polyethylene glycol
chains, carboxylic acid, amine, and thiol groups. Their
colloidal stability in various aqueous buffer solutions as
well as human plasma and serum was investigated to
allow implementation in biomedical and sensing
applications.status: publishe
Transitoriness in cancer patients: a cross-sectional survey of lung and gastrointestinal cancer patients.
Despite earlier diagnosis and advancements in treatment, cancer remains a leading cause of death in the world (13% of all deaths according to the World Health Organization) among men and women. Cancer accounts for approximately 20% of the deaths in the USA every year. Here, we report the findings from a cross-sectional survey of psychosocial factors in lung and gastrointestinal cancer patients. The aim of the study was to explore the associations among transitoriness, uncertainty, and locus of control (LOC) with quality of life. Transitoriness is defined as a person's confrontation with life's finitude due to a cancer diagnosis.
A total of 126 patients with lung or gastrointestinal cancer completed eight self-reporting questionnaires addressing demographics, spiritual perspective, symptom burden, transitoriness, uncertainty, LOC, and quality of life.
Transitoriness, uncertainty, and LOC were significantly associated with one another (r = 0.3267, p = 0.0002/r = 0.1994, p = 0.0252, respectively). LOC/belief in chance has a significant inverse relationship with patients' quality of life (r = -0.2505, p = 0.0047). Transitoriness, uncertainty, and LOC were found to have a significant inverse relationship with patients' quality of life (transitoriness state: r = -0.5363, p = 0.0000/trait: r = -0.4629, p = 0.0000/uncertainty: r = -0.4929, p = 0.0000/internal LOC: r = 0.1759, p = 0.0489/chance LOC: r = -0.2505, p = 0.0047).
Transitoriness, uncertainty, and LOC are important concepts as they adversely influence patients' quality of life. Incorporating this finding into the care of cancer patients may provide them with the support they need to cope with treatment and maintenance of a positive quality of life