2,363 research outputs found
External quality measurements reveal internal processes
With the present developments in CA technology it becomes possible to fine tune the storage conditions to the specific needs of the product. This generates the need to know the exact quality conditions of the product before storage starts. By measuring the initial quality we can determine these conditions optimally. At present the most likely candidates to assess the initial quality with fast and non-destructive measurements are colour, chlorophyll fluorescence, and maybe NIR spectroscopy. Two examples are presented where initial colour measurements on all products in a batch can be shown to be indicative for the keeping quality of that batch. The first example focuses on how initial colour measurements using a 3CCD video camera can be utilised to predict the keeping quality of a batch of cucumbers where colour itself is regarded as the most important quality attribute. The second example focuses on how colour measurements can be used to predict the keeping quality of a batch of strawberries where the ability to suppress a Botrytis cinerea infection is the most important quality attribute. Furthermore, attention is given to the use of modulated chlorophyll fluorescence imaging as a possible initial quality indicator for rose leafy stem cuttings. The level of inhomogeneity in the quantum yield of photochmistry od PSII of leaves of rose cuttings may be an indictor of the capability of the cutting to recover from severance, and to form roots and generate regrowt
Effects of ca treatments and temperature on broccoli colour development
Broccoli combines high contents of vitamins, fibres and glucosinolates with a low calorie count and is sometimes referred to as the ‘crown jewel of nutrition’. Colour is one of the most important quality attributes of broccoli, and yellowing due to senescence of broccoli florets is the main external quality problem in the broccoli supply chain. Controlled Atmosphere (CA) is a very effective method to maintain broccoli quality but the effects of CA on colour retention have not been studied extensively. The aim of this paper is to characterise the colour behaviour (measured by RGB colour image analysis) of broccoli as affected by CA and temperature. Data on colour behaviour and gas exchange were gathered for broccoli heads that were stored in containers at three temperatures and subjected to four levels of O2 and three levels of CO2. Gas conditions and temperature have a clear effect on the colour change of broccoli especially at low O2 in combination with high CO2. An integrated colour model is proposed that combines a colour model with a standard gas exchange model. The colour model is based on three differential equations describing the formation of (blue/green) chlorophyllide from the colourless precursor, the bidirectional conversion of chlorophyllide into (blue/green) chlorophyll, and the decay of chlorophyllide. During the first step of building the integrated model, gas exchange data were analysed simultaneously using multi response regression analysis. No fermentation was encountered for this batch of broccoli. During the second step it was found that only one of the reactions of the colour model, the decay of chlorophyllide, is affected by the gas conditions. In the final step, a multi-response approach was applied where gas exchange parameters were estimated using the gas exchange model, the colour parameters were estimated using the colour model with both models linked via the reaction rate constant affected by the gas conditions. Such a calibrated, integrated, model could be used as a tool for predicting colour change in the postharvest chain
A Hybrid Approach for Aspect-Based Sentiment Analysis Using Deep Contextual Word Embeddings and Hierarchical Attention
The Web has become the main platform where people express their opinions
about entities of interest and their associated aspects. Aspect-Based Sentiment
Analysis (ABSA) aims to automatically compute the sentiment towards these
aspects from opinionated text. In this paper we extend the state-of-the-art
Hybrid Approach for Aspect-Based Sentiment Analysis (HAABSA) method in two
directions. First we replace the non-contextual word embeddings with deep
contextual word embeddings in order to better cope with the word semantics in a
given text. Second, we use hierarchical attention by adding an extra attention
layer to the HAABSA high-level representations in order to increase the method
flexibility in modeling the input data. Using two standard datasets (SemEval
2015 and SemEval 2016) we show that the proposed extensions improve the
accuracy of the built model for ABSA.Comment: Accepted for publication in the 20th International Conference on Web
Engineering (ICWE 2020), Helsinki Finland, 9-12 June 202
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Exciton Condensation in Molecular-Scale van der Waals Stacks
Recent experiments have realized the Bose-Einstein condensation of excitons, known as exciton condensation, in extended systems such as bilayer graphene and van der Waals heterostructures. Here we computationally demonstrate the beginnings of exciton condensation in multilayer, molecular-scale van der Waals stacks composed of benzene subunits. The populations of excitons, which are computed from the largest eigenvalue of the particle-hole reduced density matrix (RDM) through advanced variational RDM calculations, are shown to increase with the length of the stack. The large eigenvalue indicates a nonclassical long-range ordering of the excitons that can support the frictionless flow of energy. Moreover, we use chemical substitutions and geometric modifications to tune the extent of the condensation. Results suggest exciton condensation in a potentially large family of molecular systems with applications to energy-efficient transport
Perioperative Cardiovascular Risk Stratification and Modification
Worldwide, annually approximately 100 million people undergo some form of non-cardiac surgery.
Cardiac events, such as myocardial infarction are a major cause of perioperative morbidity and mortality
in these patients. Though the true incidence of perioperative cardiac complications is difficult
to assess, it is estimated that approximately 2.0–3.5% of patients undergoing major non-cardiac
surgery experience a major adverse cardiac event. Furthermore an estimated 0.5–1.5% of patients
die within 30 days after the surgical procedure due to a cardiovascular cause. The pathophysiology
of perioperative cardiac events is complex. Similar to the non-operative setting it is thought that
approximately half of all perioperative myocardial infarctions are attributable to a sustained coronary
oxygen demand/supply mismatch. Coronary plaque rupture, leading to thrombus formation
and subsequent vessel occlusion, is thought to be the other important cause of acute perioperative
coronary syndromes
Outcomes of tuberculosis patients who start antiretroviral therapy under routine programme conditions in Malawi
SETTING: Public sector facilities in Malawi providing antiretroviral therapy (ART) to human immunodeficiency virus (HIV) positive patients, including those with tuberculosis (TB). OBJECTIVES: To compare 6-month and 12-month cohort treatment outcomes of HIV-positive TB patients and HIV-positive non-TB patients treated with ART. DESIGN: Retrospective data collection using ART patient master cards and ART patient registers. RESULTS: Between July and September 2005, 7905 patients started ART, 6967 with a non-TB diagnosis and 938 with a diagnosis of active TB. 6-month cohort outcomes of non-TB and TB patients censored on 31 March 2006 showed significantly more TB patients alive and on ART (77%) compared with non-TB patients (71%) (P < 0.001). Between January and March 2005, 4580 patients started ART, 4179 with a non-TB diagnosis and 401 with a diagnosis of active TB. 12-month cohort outcomes of non-TB and TB patients censored on 31 March 2006 showed significantly more TB patients alive and on ART (74%) compared with non-TB patients (66%) (P < 0.001). Other outcomes of default and transfer out were also significantly less frequent in TB compared with non-TB patients. CONCLUSION: HIV-positive TB patients on ART in Malawi have generally good treatment outcomes, and more patients need to access this HIV treatment
Self-Assembly of Supramolecules Consisting of Octyl Gallate Hydrogen Bonded to Polyisoprene-block-poly(vinylpyridine) Diblock Copolymers
Synchrotron radiation was used to investigate the self-assembly in two comb-shaped supramolecules systems consisting of octyl gallate (OG), i.e., 1-octyl-3,4,5-trihydroxybenzoate, hydrogen bonded to the pyridine groups of polyisoprene-block-poly(vinylpyridine) diblock copolymers. In the case of the 1,2-polyisoprene-block-poly(4-vinylpyridine)(OG)x system, self-assembly was only observed for x ≥0.5, where x denotes the number of OG molecules per pyridine group. For x = 0.5, 0.75, 1.0, and 1.2 the system self-assembled in the form of hexagonally ordered cylinders of P4VP(OG) throughout the entire temperature range of 25-200 °C investigated. For the 1,4-polyisoprene-block-poly(2-vinylpyridine)(OG)x system, on the other hand, a considerably more complex phase behavior was found, including the formation of cubic, hexagonally ordered cylinders and lamellar morphologies. In this case several order-order transitions were observed as a function of temperature, including a lamellar to lamellar transition involving a collapse of the layer thickness. The absence of hydrogen bonding between the octyl gallate molecules and the pyridine groups at elevated temperatures is argued to be a key factor for many of the phenomena observed.
Rapid and quantitative detection of homologous and non-homologous recombination events using three oligonucleotide MLPA
Embryonic stem (ES) cell technology allows modification of the mouse germline from large deletions and insertions to single nucleotide substitutions by homologous recombination. Identification of these rare events demands an accurate and fast detection method. Current methods for detection rely on Southern blotting and/or conventional PCR. Both the techniques have major drawbacks, Southern blotting is time-consuming and PCR can generate false positives. As an alternative, we here demonstrate a novel approach of Multiplex Ligation-dependent Probe Amplification (MLPA) as a quick, quantitative and reliable method for the detection of homologous, non-homologous and incomplete recombination events in ES cell clones. We have adapted MLPA to detect homologous recombinants in ES cell clones targeted with two different constructs: one introduces a single nucleotide change in the PCNA gene and the other allows for a conditional inactivation of the wild-type PCNA allele. By using MLPA probes consisting of three oligonucleotides we were able to simultaneously detect and quantify both wild-type and mutant alleles
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