221 research outputs found
Relation between the Ultrasonic Attenuation and the Porosity of a RTM Composite Plate
AbstractWe propose a comparative study of X-ray tomography and ultrasonic reflection methods, for determining the porosity of a composite plate realized in LOMC with an industrial process. We measure the attenuation of ultrasound propagating in the thickness by using 10MHz plane transducer in pulse-echo mode. Comparing these results to the 2D porosity tomographic map allows establishing a relation between attenuation and porosity. A C-scan picture of the plate given by the echoes reflected by the rear surface also provides a local information on the attenuation. Furthermore, we propose a method for the mapping of the reflecting sources as the included bubbles and the interfaces resin/fibers
Atypical form of early neonatal infection with Salmonella enterica: case report with literature review
Salmonella are rarely responsible for neonatal or perinatal infection. An annual incidence of 75/100000 births are reported in the USA. The authors present a case of a newborn with neonatal salmonellosis in the context of maternal infection in the days preceding the birth, documented retrospectively. This is a case of a 38-week male infant born via spontaneous vaginal delivery. There was a premature rupture of the membranes (13 hours). The mother gave a history of fever and diarrhea of ten days prior to delivery. She had fever of 38.3°C during labor. Prophylactic antibiotic treatment with amoxicillin was established. Thirty-two hours after birth, the baby developed fever, lethargy, and was not accepting feeds. On admission, physical examination showed fever, tachycardia, correct blood pressure and isolated jaundice. The blood count found a leukopenia, a thrombocytopenia, a CRP at 35mg/l. Parenteral antibiotic therapy with cefotaxime and amikacin was started. Apyrexia is obtained after 48 hours of intravenous treatment. Stool culture of the newborn grew after 48 hours and for the mother after 3 days. The germ identified was Salmonella enterica Serovar 4,5,12:i:-. Blood cultures were performed on the mothers and the baby, but the cultures were negative. The baby responded and was discharged on the 15th day of delivery. The mother’s condition was complicated by a Guillan Barré syndrome that required a transfer to neurology. Neonatal salmonellosis may have non-specific clinical symptoms. Management is based on early antibiotic therapy with a third-generation cephalosporin as first-line therapy. The measure in preventing the spread of infection in the neonatology is essential to avoid secondary cases
Testing Swampland Conjectures with Machine Learning
We consider Type IIB compactifications on an isotropic torus threaded
by geometric and non geometric fluxes. For this particular setup we apply
supervised machine learning techniques, namely an artificial neural network
coupled to a genetic algorithm, in order to obtain more than sixty thousand
flux configurations yielding to a scalar potential with at least one critical
point. We observe that both stable AdS vacua with large moduli masses and small
vacuum energy as well as unstable dS vacua with small tachyonic mass and large
energy are absent, in accordance to the Refined de Sitter Conjecture. Moreover,
by considering a hierarchy among fluxes, we observe that perturbative solutions
with small values for the vacuum energy and moduli masses are favored, as well
as scenarios in which the lightest modulus mass is much greater than the
corresponding AdS vacuum scale. Finally we apply some results on Random Matrix
Theory to conclude that the most probable mass spectrum derived from this
string setup is that satisfying the Refined de Sitter and AdS scale
conjectures.Comment: 30 pages, 14 Figures. (v2) References adde
Superconformal indices at large N and the entropy of AdS5 x SE5 black holes
The large N limit of the four-dimensional superconformal index was computed and successfully compared to the entropy of a class of AdS5 black holes only in the particular case of equal angular momenta. Using the Bethe ansatz formulation, we compute the index at large N with arbitrary chemical potentials for all charges and angular momenta, for general four-dimensional conformal theories with a holographic dual. We conjecture and bring some evidence that a particular universal contribution to the sum over Bethe vacua dominates the index at large N. For SYM, this contribution correctly leads to the entropy of BPS Kerr-Newman black holes in AdS5 x S5 for arbitrary values of the conserved charges, thus completing the microscopic derivation of their microstates. We also consider theories dual to AdS5 x SE5, where SE5 is a Sasaki-Einstein manifold. We first check our results against the so-called universal black hole. We then explicitly construct the near-horizon geometry of BPS Kerr-Newman black holes in AdS5 T^{1,1}, charged under the baryonic symmetry of the conifold theory and with equal angular momenta. We compute the entropy of these black holes using the attractor mechanism and find complete agreement with the field theory predictions
Discrete R-symmetries and Anomaly Universality in Heterotic Orbifolds
We study discrete R-symmetries, which appear in 4D low energy effective field
theory derived from hetetoric orbifold models. We derive the R-symmetries
directly from geometrical symmetries of orbifolds. In particular, we obtain the
corresponding R-charges by requiring that the couplings be invariant under
these symmetries. This allows for a more general treatment than the explicit
computations of correlation functions made previously by the authors, including
models with discrete Wilson lines, and orbifold symmetries beyond
plane-by-plane rotational invariance. Surprisingly, for the cases covered by
earlier explicit computations, the R-charges differ from the previous result.
We study the anomalies associated with these R-symmetries, and comment on the
results.Comment: 21 pages, 2 figures. Minor changes, typos corrected. Matches JHEP
published versio
Isolation by Miniaturized Culture Chip of an Antarctic bacterium Aequorivita sp. with antimicrobial and anthelmintic activity
Microbes are prolific sources of bioactive molecules; however, the cultivability issue has severely hampered access to microbial diversity. Novel secondary metabolites from as-yet-unknown or atypical microorganisms from extreme environments have realistic potential to lead to new drugs with benefits for human health. Here, we used a novel approach that mimics the natural environment by using a Miniaturized Culture Chip allowing the isolation of several bacterial strains from Antarctic shallow water sediments under near natural conditions. A Gram-negative Antarctic bacterium belonging to the genus Aequorivita was subjected to further analyses. The Aequorivita sp. genome was sequenced and a bioinformatic approach was applied to identify biosynthetic gene clusters. The extract of the Aequorivita sp. showed antimicrobial and anthelmintic activity towards Multidrug resistant bacteria and the nematode Caenorhabditis elegans. This is the first multi-approach study exploring the genomics and biotechnological potential of the genus Aequorivita that is a promising candidate for pharmaceutical applications
European Consortium of Microbial Resources Centres (EMbaRC): Secure the future of microbial resources at laboratory scale
[Excerpt] EMbaRC is an EU project which aims to improve, coordinate and validate microbial resource centre (MRC) delivery to the European and International researchers. To ensure harmonisation of the quality of MRCs, EMbaRC plans to take the current OECD best practice guidelines and emerging national standards for Biological Resource Centres (BRCs) to the international level. Outreach and training activities will ensure that not only the consortium but that all European collections operate to the standards required to deliver products and services of consistent quality thus meeting customer needs. A one-stop access to the collections of EMbaRC and the wider European BRC community via a searchable web portal building on the outcomes of the CABRI and EBRCN is being developed. (...
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