3,272 research outputs found
Life cycle assessment of Swiss organic farming systems
The impacts of organic and integrated farming systems in Switzerland on the environment have been assessed in a comprehensive study by the life cycle assessment method. This paper reports a comparison of the treatments of the DOC experiment. Organic farming showed clear ecological advantages particularly for eco- and human toxicity, resource use and biodiversity. These ecological advantages only partly apply to nutrient losses and are not always found for single products. Per kg of organic product, higher impacts were often found for global warming potential, ozone formation, eutrophication and acidification compared to integrated production. In the same crop rotation with the same amount of organic fertilisers there were no systematic differences in soil quality of organic compared with integrated production. Further improvement of the environmental performance of organic farming should focus on achieving higher yields of good quality â especially in potatoes and cereals - by using inputs more efficiently and minimising nitrogen losses
Antidepressant medication and ocular factors in association with the need for anti-VEGF retreatment in neovascular age-related macular degeneration.
Vascular endothelial growth factor (VEGF) is a key player in the pathogenesis of neovascular age-related macular degeneration (nAMD) and is also involved in the final common pathway of antidepressant medication. This study investigated the relationship between the need for anti-VEGF retreatment in patients with nAMD and antidepressant medication, and the potential impact of ocular structural factors.
Data from two identical prospective 2-year treatment protocols using ranibizumab or aflibercept in a variable-dosing regimen ('Observe-and-Plan') were analysed. Retreatment requirement was compared with antidepressant medication intake (primary outcome) and a variety of ocular factors from baseline and from month 3 response (secondary outcomes), using univariate and multivariate analyses.
Of the 206 included patients (227 eyes), 19 were on antidepressant medication. Their nAMD eyes significantly more often had pigment epithelium detachment (PED, p=0.04). Multivariate analysis revealed a significant association between anti-VEGF retreatment requirement and antidepressant medication use (p=0.027), as well as thicker central retinal thickness at month 3 (p<0.0001) and month 3 PED height (p=0.001).
This study provides evidence that treatment with antidepressant medication increases the anti-VEGF retreatment requirement in patients with nAMD, possibly through the interplay of antidepressant medication, depression status and VEGF levels
The Holographic Dual of 2+1 Dimensional QFTs with N=1 SUSY and Massive Fundamental Flavours
The Maldacena Nastase solution is generalised to include massive fundamental
matter through the addition of a flavour profile. This gives a holographic dual
to N=1 SYM-CS with massive fundamental matter with a singularity free IR. We
study this solution in some detail confirming confinement and asymptotic
freedom. A recently proposed solution generating technique is then applied
which results in a new type-IIA supergravity solution. In a certain limit the
geometry of this solution is asymptotically AdS_4X Y, where Y is the metric at
the base of the Bryant-Salamon G_2 cone, which has topology S^3XS^3.Comment: 31 pages plus appendices, 6 figures. v3: Typos corrected, version to
appear in JHE
Building capacity for public and population health research in Africa : the consortium for advanced research training in Africa (CARTA) model
Background: Globally, sub-Saharan Africa bears the greatest burden of disease. Strengthened research
capacity to understand the social determinants of health among different African populations is key to
addressing the drivers of poor health and developing interventions to improve health outcomes and health
systems in the region. Yet, the continent clearly lacks centers of research excellence that can generate a strong
evidence base to address the regionâs socio-economic and health problems.
Objective and program overview: We describe the recently launched Consortium for Advanced Research
Training in Africa (CARTA), which brings together a network of nine academic and four research institutions
from West, East, Central, and Southern Africa, and select northern universities and training institutes.
CARTAâs program of activities comprises two primary, interrelated, and mutually reinforcing objectives: to
strengthen research infrastructure and capacity at African universities; and to support doctoral training
through the creation of a collaborative doctoral training program in population and public health. The
ultimate goal of CARTA is to build local research capacity to understand the determinants of population
health and effectively intervene to improve health outcomes and health systems.
Conclusions: CARTAâs focus on the local production of networked and high-skilled researchers committed to
working in sub-Saharan Africa, and on the concomitant increase in local research and training capacity of
African universities and research institutes addresses the inability of existing programs to create a critical
mass of well-trained and networked researchers across the continent. The initiativeâs goal of strengthening
human resources and university-wide systems critical to the success and sustainability of research
productivity in public and population health will rejuvenate institutional teaching, research, and administrative
systems
A complementary compact laser based neutron source
Several experiments of neutron generation using high intensity laser sources,
with a power exceeding 10^19W/cm^2 via TNSA (Target Normal Sheath Acceleration)
or other similar methods, have been performed in the past years in different
laboratories. However, so far there is no one running neutron source based on
such a technology. In the framework of the Conceptual Report Design of a new
accelerator in the Eupraxia project we are studying the possibility to have a
laser-based neutron source, not only by TNSA but also from self-injection
schemes. We focus our attention on the applications in cultural heritage
studies as well also on the complementary role that such a source can have in
the framework of large facilities devoted to radiation production.Comment: 4 pages, two figures, 3rd European Advanced Accelerators Concept
Counterterms vs. Dualities
We investigate and clarify the mutual compatibility of the higher order
corrections arising in supergravity and string theory effective actions and the
non-linear duality symmetries of these theories. Starting from a conventional
tree level action leading to duality invariant equations of motion, we show how
to accommodate duality invariant counterterms given as functionals of both
electric and magnetic fields in a perturbative expansion, and to deduce from
them a non-polynomial bona fide action satisfying the Gaillard-Zumino
constraint. There exists a corresponding consistency constraint in the
non-covariant Henneaux-Teitelboim formalism which ensures that one can always
restore diffeomorphism invariance by perturbatively solving this functional
identity. We illustrate how this procedure works for the R^2 \nabla F \nabla F
and F^4 counterterms in Maxwell theory.Comment: 15 page
Note on Tests of the Factorization Hypothesis and the Determination of Meson Decay Constants
We discuss various tests of the factorization hypothesis making use of the
close relationship between semi-leptonic and factorized nonleptonic decay
amplitudes. It is pointed out that factorization leads to truely
model-independent predictions for the ratio of nonleptonic to semi-leptonic
decay rates, if in the nonleptonic decay a spin one meson of arbitrary mass or
a pion take the place of the lepton pair. Where the decay constants of those
mesons are known, these predictions represent ideal tests of the factorization
hypothesis. In other cases they may be used to extract the decay constants.
Currently available data on the decays are shown to be in excellent agreement with
the factorization results. A weighted average of the four independent values
for the QCD coefficient extracted from the data gives
suggesting that it may be equal to the Wilson coefficient evaluated
at the scale .Comment: (9 pages, ReVTeX, no figures), HD-THEP-92-3
Kaon mixing and the charm mass
We study contributions to the Delta S=2 weak Chiral Lagrangian producing
K0-K0bar mixing which are not enhanced by the charm mass. For the real part,
these contributions turn out to be related to the box diagram with up quarks
but, unlike in perturbation theory, they do not vanish in the limit m_u->0.
They increase the leading contribution to the K_L-K_S mass difference by ~10%.
This means that short distances amount to (90+-15)% of this mass difference.
For the imaginary part, we find a correction to the lambda_c^2 m_c^2 term of
-5% from the integration of charm, which is a small contribution to epsilon_K.
The calculation is done in the large-Nc limit and we show explicitly how to
match short and long distances.Comment: 20 pages, 5 figures. Typos fixe
Optical coherence tomography (OCT) to image active and inactive retinoblastomas as well as retinomas.
To illustrate Optical Coherence Tomography (OCT) images of active and inactive retinoblastoma (Rb) tumours.
Current observational study included patients diagnosed with retinoblastoma and retinoma who were presented at Amsterdam UMC and Jules-Gonin Eye Hospital, between November 2010 and October 2017. Patients aged between 0 and 4 years were imaged under general anaesthesia with handheld OCT in supine position. Patients older than 4 years were imaged with the conventional OCT (Heidelberg Engineering, Heidelberg Spectralis, Germany). All patients included were divided into two groups: active and inactive tumours (retinoma and regression patterns). Patients' medical records and OCT images were analysed during meetings via discussions by ophthalmologists and physicists.
Twelve Dutch and 8 Swiss patients were divided into two groups: 2 patients with active tumour versus 18 patients with inactive tumour. Subsequently, inactive group could be divided in two groups, which consisted of 10 patients with retinoma and 8 patients with different regression pattern types. Of all included patients, 15 were male (75%). Median age at diagnosis was 18.0 months (range 0.19-715.2 months). A total of 12 retinoblastoma (active and inactive) and 8 retinoma foci were investigated by OCT. No distinction could be made between active and inactive tumours using only OCT.
Optical coherence tomography alone cannot distinguish between active and inactive Rbs. However, handheld OCT adds useful information to the established imaging techniques in the monitoring and follow-up of retinoblastoma patients. With this study, we provide an overview of OCT images of active and inactive Rbs
Evolutionary Multi-Objective Design of SARS-CoV-2 Protease Inhibitor Candidates
Computational drug design based on artificial intelligence is an emerging
research area. At the time of writing this paper, the world suffers from an
outbreak of the coronavirus SARS-CoV-2. A promising way to stop the virus
replication is via protease inhibition. We propose an evolutionary
multi-objective algorithm (EMOA) to design potential protease inhibitors for
SARS-CoV-2's main protease. Based on the SELFIES representation the EMOA
maximizes the binding of candidate ligands to the protein using the docking
tool QuickVina 2, while at the same time taking into account further objectives
like drug-likeliness or the fulfillment of filter constraints. The experimental
part analyzes the evolutionary process and discusses the inhibitor candidates.Comment: 15 pages, 7 figures, submitted to PPSN 202
- âŠ