244 research outputs found
Improving natural pest suppression in arable farming: field margins and the importance of ground dwelling predators
Overwintering of soil dwelling arthropods and especially carabid beetles was much higher in unmown perennial field margins than in mown grass strips or barren crop fields. Over 200 generalist predators per m2 were trapped in field margin enclosures after hibernation. Predator exclusion experiments showed that high-density aphid colonies in May were reduced by 49% compared to predator-free conditions, both in field margins and in summer wheat crops. Over a 4 years period, aphid infestation levels in summer wheat and potatoes were 15%-65% lower in a farming system with a network of perennial field margins, compared to a system without field margins. However, Diamond back moth and slug damage in Brussels sprouts were higher in the system with field margins compared to the control system without margins
Interobserver and intraobserver variability in the radiological assessment of sialolithiasis using cone beam computed tomography
BACKGROUND: Data regarding the inter- and intraobserver variability in the radiological assessment of sialolithiasis using cone beam computed tomography are missing in the current literature. This study assessed the inter- and intraobserver variability in the radiological assessment of sialolithiasis using cone beam computed tomography (CBCT). MATERIAL AND METHODS: In 107 patients, 130 salivary glands (65 parotid and 65 submandibular) with clinical signs of obstruction were assessed by four independent observers; 2 residents OMFS and 2 experienced OMFS. The observers analyzed the CBCT images and determined the absence or presence of one or more salivary stones in the affected gland. This procedure was repeated after three months. RESULTS: Interobserver agreements showed kappa values of 0.84 for the parotid gland, and 0.93 for the submandibular gland. Intraobserver agreements for the whole group reported kappa values between 0.83 - 0.95. There was no significant difference between residents and experienced OMFS. CONCLUSIONS: Due to the good inter- and intraobserver agreement, CBCT appears to be a reproducible imaging modality for detecting salivary stones in patients with signs and symptoms of obstructed parotid and submandibular glands. Key words:Salivary gland calculi, cone-beam computed tomography, observer variation
Effecten van waterrecirculatie op voeropname en voerbenutting van paling
Recirculatie van water in visteeltsystemen veroorzaakt sterke en complexe veranderingen in waterkwaliteit. Visteelt in recirculatiesystemen vereist daarom grondige kennis van de behoeften die vissen aan de waterkwaliteit stellen. Voor een relatief klein aantal parameters, zoals zuurstof, pH, ammonium, nitriet en nitraat kunnen deze veranderingen goed , beschreven worden. Voor die parameters zijn bij paling redelijk goed onderbouwde grenswaarden ontwikkeld. Met behulp van dergelijke grenswaarden kunnen systemen ontworpen worden en kan met het dagelijkse management de waterkwaliteit bijgestuurd worde
A review of the Dividend Discount Model: from deterministic to stochastic models
This chapter presents a review of the dividend discount models starting from
the basic models (Williams 1938, Gordon and Shapiro 1956) to more recent and
complex models (Ghezzi and Piccardi 2003, Barbu et al. 2017, D'Amico and De
Blasis 2018) with a focus on the modelling of the dividend process rather than
the discounting factor, that is assumed constant in most of the models. The
Chapter starts with an introduction of the basic valuation model with some
general aspects to consider when performing the computation. Then, Section 1.3
presents the Gordon growth model (Gordon 1962) with some of its extensions
(Malkiel 1963, Fuller and Hsia 1984, Molodovsky et al. 1965, Brooks and Helms
1990, Barsky and De Long 1993), and reports some empirical evidence. Extended
reviews of the Gordon stock valuation model and its extensions can be found in
Kamstra (2003) and Damodaran (2012). In Section 1.4, the focus is directed to
more recent advancements which make us of the Markov chain to model the
dividend process (Hurley and Johnson 1994, Yao 1997, Hurley and Johnson 1998,
Ghezzi and Piccardi 2003, Barbu et al. 2017, D'Amico and De Blasis 2018). The
advantage of these models is the possibility to obtain a different valuation
that depends on the state of the dividend series, allowing the model to be
closer to reality. In addition, these models permit to obtain a measure of the
risk of the single stock or a portfolio of stocks
Immediate and long-term impact of the COVID-19 pandemic on delivery of surgical services
Background
The ongoing pandemic is having a collateral health effect on delivery of surgical care to millions of patients. Very little is known about pandemic management and effects on other services, including delivery of surgery.
Methods
This was a scoping review of all available literature pertaining to COVID‐19 and surgery, using electronic databases, society websites, webinars and preprint repositories.
Results
Several perioperative guidelines have been issued within a short time. Many suggestions are contradictory and based on anecdotal data at best. As regions with the highest volume of operations per capita are being hit, an unprecedented number of operations are being cancelled or deferred. No major stakeholder seems to have considered how a pandemic deprives patients with a surgical condition of resources, with patients disproportionally affected owing to the nature of treatment (use of anaesthesia, operating rooms, protective equipment, physical invasion and need for perioperative care). No recommendations exist regarding how to reopen surgical delivery. The postpandemic evaluation and future planning should involve surgical services as an essential part to maintain appropriate surgical care for the population during an outbreak. Surgical delivery, owing to its cross‐cutting nature and synergistic effects on health systems at large, needs to be built into the WHO agenda for national health planning.
Conclusion
Patients are being deprived of surgical access, with uncertain loss of function and risk of adverse prognosis as a collateral effect of the pandemic. Surgical services need a contingency plan for maintaining surgical care in an ongoing or postpandemic phase.publishedVersio
How Did the Gene Become a Chemical Compound? The Ontology of the Gene and the Patenting of DNA
Cytomolecular identification of individual wheat-wheat chromosome arm associations in wheat-rye hybrids
Chromosome pairing in the meiotic metaphase I of wheatrye
hybrids has been characterized by sequential genomic
and fluorescent in situ hybridization allowing not only the
discrimination of wheat and rye chromosomes, but also the
identification of the individual wheat and rye chromosome
arms involved in the chromosome associations. The majority
of associations (93.8%) were observed between the wheat
chromosomes. The largest number of wheat-wheat chromosome
associations (53%) was detected between the A and D
genomes, while the frequency of B-D and A-B associations
was significantly lower (32 and 8%, respectively). Among the
A-D chromosome associations, pairing between the 3AL and
3DL arms was observed with the highest frequency, while
the most frequent of all the chromosome associations (0.113/
cell) was found to be the 3DS-3BS. Differences in the pairing
frequency of the individual chromosome arms of wheat-rye
hybrids have been discussed in relation to the homoeologous
relationships between the constituent genomes of
hexaploid wheat
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