Evaluation of the nutrient status of wheat plants

The balance of the principal ionic constituents in plants is reviewed in relation to the requirements for each of the elements, and for total accumulation as reflected in the total cation content (C), the inorganic anion conent (A) and the organic anion content (C-A). The balance in young wheat plants is investigated by means of adding various combinations of the principal ions to the soil. A summary of tests on adequacy of supply with the principal nutrient ions and of accumulation of cations, inorganic anions and organic anions, based on critical values. for contents in the plant material, is presented for diagnosing the nutrient status in relation to capacity for maximum growth

Nitrogen nutrition of rice plants measured by growth and nutrient content in pot experiments. 3. Changes during growth.

Young rice plants cv. IR-5 in flooded sand culture grew better with ammonium than with nitrate as N source; yield differences were initiated by a higher rate of tillering and leaf expansion with ammonium nutrition during the first stage of exponential growth. When complete foliage cover had been obtained and further DM increases were linearly related to growth duration, nitrate was less readily assimilated than ammonium, but growth rate was the same for both forms of N because it was controlled mainly by environment and nutrient supply rather than by leaf area, form of available N or concentration of N in the tissues. Restoration of N supply to an N-depleted culture of well-developed plants showed that ammonium produced an earlier renewal of growth; plants yielded more on a given date than with nitrate although they eventually regained the same rate of linear growth. Plants given nitrate contained more carboxylates than those given ammonium, irrespective of plant age or temporary N shortage. (Abstract retrieved from CAB Abstracts by CABI’s permission

Diffusion of personalised services among Dutch municipalities: evolving channels of persuasion

In many European countries, municipalities are becoming increasingly important as providers of electronic public services to their citizens. One of the horizons for further expansion is the delivery of personalised electronic services. In this paper, we describe the diffusion of personalised services in the Netherlands over the period 2006-2009 and investigate how and why various municipalities adopted personalised electronic services. In achieving this, we analyse data that were gathered during interviews with key stakeholders in ten selected Dutch municipalities. We synthesise the findings in an explanatory model of personalised electronic service delivery diffusion. The model emphasizes persuasive pressures that are channelled to potential adopters of personalised services. Furthermore, the model shows how persuasive pressure (as perceived by adopters) is followed-up by organisational search activities, and how, in various circumstances, the idea of personalised services is ‘framed’ by innovation champions, knowledge brokers and new members of staff as to appeal to specific organisational priorities and ambitions. In doing so, this article contributes to an institutional view on adoption and diffusion of innovations, in which (1) horizontal and vertical channels of persuasion and (2) human agency, rather than technological opportunity and rational cost-benefit considerations, account for actual diffusion of innovations

Efficacy of a dynamic collimator for overranging dose reduction in a second- and third-generation dual source CT scanner

Objectives: The purpose of this study was to assess the efficacy of the renewed dynamic collimator in a third-generation dual source CT (DSCT) scanner and to determine the improvements over the second-generation scanner. Methods: Collimator efficacy is defined as the percentage overranging dose in terms of dose–length product (DLP) that is blocked by the dynamic collimator relative to the total overranging dose in case of a static collimator. Efficacy was assessed at various pitch values and different scan lengths. The number of additional rotations due to overranging and effective scan length were calculated on the basis of reported scanning parameters. On the basis of these values, the efficacy of the collimator was calculated. Results: The second-generation scanner showed decreased performance of the dynamic collimator at increasing pitch. Efficacy dropped to 10% at the highest pitch. For the third-generation scanner the efficacy remained above 50% at higher pitch. Noise was for some pitch values slightly higher at the edge of the imaged volume, indicating a reduced scan range to reduce the overranging dose. Conclusions: The improved dynamic collimator in the third-generation scanner blocks the overranging dose for more than 50% and is more capable of shielding radiation dose, especially in high pitch scan modes. Key points: • Overranging dose is to a large extent blocked by the dynamic collimator• Efficacy is strongly improved within the third-generation DSCT scanner• Reducing th

Technological developments of X-ray computed tomography over half a century: User's influence on protocol optimization

Since the introduction of Computed Tomography (CT), technological improvements have been impressive. At the same time, the number of adjustable acquisition and reconstruction parameters has increased substantially. Overall, these developments led to improved image quality at a reduced radiation dose. However, many parameters are interrelated and part of automated algorithms. This makes it more complicated to adjust them individually and more difficult to comprehend their influence on CT protocol adjustments. Moreover, the user's influence in adapting protocol parameters is sometimes limited by the manufacturer's policy or the user's knowledge. As a consequence, optimization can be a challenge. A literature search in Embase, Medline, Cochrane, and Web of Science was performed. The literature was reviewed with the objective to collect information regarding technological developments in CT over the past five decades and the role of the associated acquisition and reconstruction parameters in the optimization process

ArCo: the Italian Cultural Heritage Knowledge Graph

ArCo is the Italian Cultural Heritage knowledge graph, consisting of a network of seven vocabularies and 169 million triples about 820 thousand cultural entities. It is distributed jointly with a SPARQL endpoint, a software for converting catalogue records to RDF, and a rich suite of documentation material (testing, evaluation, how-to, examples, etc.). ArCo is based on the official General Catalogue of the Italian Ministry of Cultural Heritage and Activities (MiBAC) - and its associated encoding regulations - which collects and validates the catalogue records of (ideally) all Italian Cultural Heritage properties (excluding libraries and archives), contributed by CH administrators from all over Italy. We present its structure, design methods and tools, its growing community, and delineate its importance, quality, and impact

Multi-detector row computed tomography angiography of peripheral arterial disease

With the introduction of multi-detector row computed tomography (MDCT), scan speed and image quality has improved considerably. Since the longitudinal coverage is no longer a limitation, multi-detector row computed tomography angiography (MDCTA) is increasingly used to depict the peripheral arterial runoff. Hence, it is important to know the advantages and limitations of this new non-invasive alternative for the reference test, digital subtraction angiography. Optimization of the acquisition parameters and the contrast delivery is important to achieve a reliable enhancement of the entire arterial runoff in patients with peripheral arterial disease (PAD) using fast CT scanners. The purpose of this review is to discuss the different scanning and injection protocols using 4-, 16-, and 64-detector row CT scanners, to propose effective methods to evaluate and to present large data sets, to discuss its clinical value and major limitations, and to review the literature on the validity, reliability, and cost-effectiveness of multi-detector row CT in the evaluation of PAD

Computed tomography segmental calcium score (SCS) to predict stenosis severity of calcified coronary lesions

To estimate the probability of a parts per thousand yen50 % coronary stenoses based on computed tomography (CT) segmental calcium score (SCS) and clinical factors. The Institutional Review Board approved the study. A training sample of 201 patients underwent CT calcium scoring and conventional coronary angiography (CCA). All patients consented to undergo CT before CCA after being informed of the additional radiation dose. SCS and calcification morphology were assessed in individual coronary segments. We explored the predictive value of patient's symptoms, clinical history, SCS and calcification morphology. We developed a prediction model in the training sample based on these variables then tested it in an independent test sample. The odds ratio (OR) for a parts per thousand yen50 % coronary stenosis was 1.8-fold greater (p = 0.006) in patients with typical chest pain, twofold (p = 0.014) greater in patients with acute coronary syndromes, twofold greater (p < 0.001) in patients with prior myocardial infarction. Spotty calcifications had an OR for a parts per thousand yen50 % stenosis 2.3-fold (p < 0.001) greater than the absence of calcifications, wide calcifications 2.7-fold (p < 0.001) greater, diffuse calcifications 4.6-fold (p < 0.001) greater. In middle segments, each unit of SCS had an OR 1.2-fold (p < 0.001) greater than in distal segments; in proximal segments the OR was 1.1-fold greater (p = 0.021). The ROC curve area of the prediction model was 0.795 (0.95 confidence interval 0.602-0.843). Validation in a test sample of 201 independent patients showed consistent diagnostic performance. In conjunction with calcification morphology, anatomical location, patient's symptoms and clinical history, SCS can be helpful to estimate the probability of a parts per thousand yen50 % coronary stenosis