2,943 research outputs found
Tensor product of motives via K\"unneth formula
Following Nori's original idea we here provide certain motivic categories
with a canonical tensor structure. These motivic categories are associated to a
cohomological functor on a suitable base category and the tensor structure is
induced by the cartesian tensor structure on the base category via a
cohomological K\"unneth formula.Comment: Revised version to appear on JPA
New Axioms in Set Theory
In this article we review the present situation in the foundations of set theory, discussing two programs meant to overcome the phenomenon of independence centered, respectively, on forcing axioms and Woodin’s V = Ultimate-L
conjecture. While doing so, we briefly introduce the key notions of set theory
Preliminary evaluation of probiotic properties of Lactobacillus strains isolated from Sardinian dairy products
Twenty-three Lactobacillus strains of dairy origin were evaluated for some functional properties relevant to their use as probiotics. A preliminary subtractive screening based on the abilities to inhibit the growth of microbial pathogens and hydrolyze conjugated bile salts was applied, and six strains were selected for further characterization including survival under gastrointestinal environmental conditions, adhesion to gut epithelial tissue, enzymatic activity, and some safety properties. All selected strains maintained elevated cell numbers under conditions simulating passage through the human gastrointestinal tract, well comparable to the values obtained for the probiotic strain Lactobacillus rhamnosus GG, and were able to adhere to Caco-2 cells to various extents (from 3 to 20%). All strains exhibited high aminopeptidase, and absent or very low proteolytic and strong β-galactosidase activities; none was found to be haemolytic or to produce biogenic amines and all were susceptible to tetracycline, chloramphenicol, erythromycin, ampicillin, and amoxicillin/clavulanic acid. Our results indicate that the Lactobacillus strains analyzed could be considered appropriate probiotic candidates, due to resistance to GIT simulated conditions, antimicrobial activity, adhesion to Caco-2 cell-line, and absence of undesirable properties. They could be used as adjunct cultures for contributing to the quality and health related functional properties of dairy products
Computing and testing a stable common currency for Mercosur countries
This paper develops a stable common currency for mid-sized open monetary economies with incomplete markets in general and the Mercosur countries in particular. The proposed currency is constructed as a derivative of a dynamic portfolio of securities that proxies the nominal exchange risk factors for a set of monies and floats against the rest of the world’s currencies. We find that the resulting optimal common currency is comprised of currencies with country weights that are statistically significant and fairly symmetrical with relatively equal weight (e.g., 22% Argentinean pesos, 27% Brazilian reals, 27% Chilean pesos, and 23% Uruguayan pesos). We also find that increasing the number of countries in a common currency tends to increase its stability. The willingness of Mercosur countries to participate in a monetary union is assessed from statistical moments of the density functions of the implied stable common currency and its components.stable common currency, open monetary economies, regime switching models, Mercosur, currency basket
Tips and tricks in triple-negative breast cancer: how to manage patients in real-life practice?
Journal ArticleSCOPUS: cp.jinfo:eu-repo/semantics/publishe
Expression of genes for subunits of plant-type RuBisCO from Chromatium and production of the enzymically active molecule in Escherichia coli
AbstractA DNA fragment containing genes for both large (A) and small (B) subunits ofribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) from a photosynthetic bacterium Chromatium vinosum was ligated with vectors for expressing unfused proteins and introduced into cells of Escherichia coli. The expressers of RuBisCO were screened on agar plates using the specific antibody raised against the native enzyme from Chromatium. The production of both subunits A and B in the expressers was demonstrated by an immunoblotting experiment. The amount of RuBisCO produced in the E. coli cells was as high as 15% of the total soluble protein after induction with isopropyl-β-D-thiogalactoside. The specific activity of enzyme molecules produced in E. coli was nearly the same as that of the original Chromatium enzyme. On gel filtration high-performance liquid chromatography the two enzymes showed identical elution behavior, strongly indicating their similar quaternary structures
An evidence-based multidisciplinary approach focused at creating algorithms for targeted therapy of bsis, cutis, and ciais caused by enterobacterales in critically ill adult patients
Prompt implementation of appropriate targeted antibiotic therapy represents a valuable approach in improving clinical and ecological outcome in critically septic patients. This multidisciplinary opinion article focused at developing evidence-based algorithms for targeted antibiotic therapy of bloodstream (BSIs), complicated urinary tract (cUTIs), and complicated intrabdominal infections (cIAIs) caused by Enterobacterales. The aim was to provide a guidance for intensive care physicians either in appropriately placing novel antibiotics or in considering strategies for sparing the broadest-spectrum antibiotics. A multidisciplinary team of experts (one intensive care physician, one infectious disease consultant, one clinical microbiologist and one MD clinical pharmacologist), performed several rounds of assessment to reach agreement in developing six different algorithms according to the susceptibility pattern (one each for multi-susceptible, extended-spectrum beta-lactamase-producing, AmpC beta-lactamase-producing, Klebsiella pneumoniae carba-penemase (KPC)-producing, OXA-48-producing, and Metallo-beta-lactamase (MBL)-produ-cing Enterobacterales). Whenever multiple therapeutic options were feasible, a hierarchical scale was established. Recommendations on antibiotic dosing optimization were also pro-vided. In order to retrieve evidence-based support for the therapeutic choices proposed in the algorithms, a comprehensive literature search was performed by a researcher on PubMed-MEDLINE from inception until March 2021. Quality and strength of evidence was established according to a hierarchical scale of the study design. Only articles published in English were included. It is expected that these algorithms, by allowing prompt revision of antibiotic regimens whenever feasible, appropriate place in therapy of novel beta-lactams, implementation of strategies for sparing the broadest-spectrum antibiotics, and pharmacoki-netic/pharmacodynamic optimization of antibiotic dosing regimens, may be helpful either in improving clinical outcome or in containing the spread of antimicrobial resistance
Collective behaviour without collective order in wild swarms of midges
Collective behaviour is a widespread phenomenon in biology, cutting through a
huge span of scales, from cell colonies up to bird flocks and fish schools. The
most prominent trait of collective behaviour is the emergence of global order:
individuals synchronize their states, giving the stunning impression that the
group behaves as one. In many biological systems, though, it is unclear whether
global order is present. A paradigmatic case is that of insect swarms, whose
erratic movements seem to suggest that group formation is a mere epiphenomenon
of the independent interaction of each individual with an external landmark. In
these cases, whether or not the group behaves truly collectively is debated.
Here, we experimentally study swarms of midges in the field and measure how
much the change of direction of one midge affects that of other individuals. We
discover that, despite the lack of collective order, swarms display very strong
correlations, totally incompatible with models of noninteracting particles. We
find that correlation increases sharply with the swarm's density, indicating
that the interaction between midges is based on a metric perception mechanism.
By means of numerical simulations we demonstrate that such growing correlation
is typical of a system close to an ordering transition. Our findings suggest
that correlation, rather than order, is the true hallmark of collective
behaviour in biological systems.Comment: The original version has been split into two parts. This first part
focuses on order vs. correlation. The second part, about finite-size scaling,
will be included in a separate paper. 15 pages, 6 figures, 1 table, 5 video
Finite-size scaling as a way to probe near-criticality in natural swarms
Collective behaviour in biological systems is often accompanied by strong
correlations. The question has therefore arisen of whether correlation is
amplified by the vicinity to some critical point in the parameters space.
Biological systems, though, are typically quite far from the thermodynamic
limit, so that the value of the control parameter at which correlation and
susceptibility peak depend on size. Hence, a system would need to readjust its
control parameter according to its size in order to be maximally correlated.
This readjustment, though, has never been observed experimentally. By gathering
three-dimensional data on swarms of midges in the field we find that swarms
tune their control parameter and size so as to maintain a scaling behaviour of
the correlation function. As a consequence, correlation length and
susceptibility scale with the system's size and swarms exhibit a near-maximal
degree of correlation at all sizes.Comment: Selected for Viewpoint in Physics; PRL Editor's Suggestio
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