1,703 research outputs found
Periodontitis and Systemic Markers of Neurodegeneration. A case-control study
Aim:
To investigate whether periodontitis is associated with amyloid beta (Aβ) peptides and whether systemic inflammation could act as a potential mediator of this link.
Materials and Methods:
A caseâcontrol study was designed including 75 patients with periodontitis (cases) and 75 ageâbalanced and genderâmatched participants without periodontitis (controls). Fullâmouth periodontal evaluation was performed in all participants. Demographic, clinical and behaviour data were also recorded. Fasting blood samples were collected, and serum levels of interleukin 6 (ILâ6), highâsensitivity Câreactive protein (hsâCRP), Aβ1â40 and Aβ1â42 were determined.
Results:
Cases showed higher levels of ILâ6 (8.7 Âą 3.2 vs. 4.8 Âą 0.5 pg/ml), hsâCRP (3.3 Âą 1.2 vs. 0.9 Âą 0.7 mg/L), Aβ1â40 (37.3 Âą 6.0 vs. 30.3 Âą 1.8 pg/ml) and Aβ1â42 (54.5 Âą 10.6 vs. 36.5 Âą 10.0 pg/ml) when compared to controls (all p < .001). Diagnosis of periodontitis was statistically significantly associated with circulating Aβ1â40 (urn:x-wiley:03036979:media:jcpe13267:jcpe13267-math-0001 = 6.9, 95% CI: 5.4â8.3; p < .001) and Aβ1â42 (urn:x-wiley:03036979:media:jcpe13267:jcpe13267-math-0002 = 17.8, 95% CI: 14.4â21.3; p < .001). Mediation analysis confirmed hsâCRP and ILâ6 as mediators of this association.
Conclusions:
Periodontitis is associated with increased peripheral levels of Aβ. This finding could be explained by enhanced systemic inflammation that can be seen in patients with periodontitis
Correlation between clustering and degree in affiliation networks
We are interested in the probability that two randomly selected neighbors of
a random vertex of degree (at least) are adjacent. We evaluate this
probability for a power law random intersection graph, where each vertex is
prescribed a collection of attributes and two vertices are adjacent whenever
they share a common attribute. We show that the probability obeys the scaling
as . Our results are mathematically rigorous. The
parameter is determined by the tail indices of power law
random weights defining the links between vertices and attributes
A people-oriented paradigm for smart cities
Most works in the literature agree on considering the Internet of Things (IoT) as the base technology to collect information related to smart cities. This information is usually offered as open data for its analysis, and to elaborate statistics or provide services which improve the management of the city, making it more efficient and more comfortable to live in. However, it is not possible to actually improve the quality of life of smart citiesâ inhabitants if there is no direct information about them and their experiences. To address this problem, we propose using a social and mobile computation model, called the Internet of People (IoP) which empowers smartphones to recollect information about their users, analyze it to obtain knowledge about their habits, and provide this knowledge as a service creating a collaborative information network. Combining IoT and IoP, we allow the smart city to dynamically adapt its services to the needs of its citizens, promoting their welfare as the main objective of the city.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech
Porous medium equation with nonlocal pressure
We provide a rather complete description of the results obtained so far on
the nonlinear diffusion equation , which describes a flow through a porous medium driven by a
nonlocal pressure. We consider constant parameters and , we assume
that the solutions are non-negative, and the problem is posed in the whole
space. We present a theory of existence of solutions, results on uniqueness,
and relation to other models. As new results of this paper, we prove the
existence of self-similar solutions in the range when and , and the
asymptotic behavior of solutions when . The cases and were
rather well known.Comment: 24 pages, 2 figure
Comparison of two multiaxial fatigue models applied to dental implants
This paper presents two multiaxial fatigue life prediction models applied to a commercial dental implant. One model is called Variable Initiation Length Model and takes into account both the crack initiation and propagation phases. The second model combines the Theory of Critical Distance with a critical plane damage model to characterise the initiation and initial propagation of micro/meso cracks in the material. This paper discusses which material properties are necessary for the implementation of these models and how to obtain them in the laboratory from simple test specimens. It also describes the FE models developed for the stress/strain and stress intensity factor characterisation in the implant. The results of applying both life prediction models are compared with experimental results arising from the application of ISO-14801 standard to a commercial dental implan
Transfer parameters for ICRP's Reference Animals and Plants in a terrestrial Mediterranean ecosystem
A system for the radiological protection of the environment (or wildlife) based on Reference Animals and Plants (RAPs) has been suggested by the International Commission on Radiological Protection (ICRP). To assess whole-body activity concentrations for RAPs and the resultant internal dose rates, transfer parameters are required. However, transfer values specifically for the taxonomic families defined for the RAPs are often sparse and furthermore can be extremely site dependent. There is also a considerable geographical bias within available transfer data, with few data for Mediterranean ecosystems. In the present work, stable element concentrations (I, Li, Be, B, Na, Mg, Al, P, S, K. Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Cs, Ba, Tl, Pb and U) in terrestrial RAPs, and the corresponding whole-body concentration ratios, CRwo, were determined in two different Mediterranean ecosystems: a Pinewood and a Dehesa (grassland with disperse tree cover). The RAPs considered in the Pinewood ecosystem were Pine Tree and Wild Grass; whereas in the Dehesa ecosystem those considered were Deer, Rat, Earthworm, Bee, Frog, Duck and Wild Grass. The CRwo values estimated from these data are compared to those reported in international compilations and databases
PIN14 COST-EFFECTIVENESS OF LINEZOLID VERSUS VANCOMYCIN IN THE TREATMENT OF NOSOCOMIAL PNEUMONIA SUSPECTED TO BE CAUSED BY METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS IN SPAIN
Biology, Methodology or Chance? The Degree Distributions of Bipartite Ecological Networks
The distribution of the number of links per species, or degree distribution, is widely used as a summary of the topology of complex networks. Degree distributions have been studied in a range of ecological networks, including both mutualistic bipartite networks of plants and pollinators or seed dispersers and antagonistic bipartite networks of plants and their consumers. The shape of a degree distribution, for example whether it follows an exponential or power-law form, is typically taken to be indicative of the processes structuring the network. The skewed degree distributions of bipartite mutualistic and antagonistic networks are usually assumed to show that ecological or co-evolutionary processes constrain the relative numbers of specialists and generalists in the network. I show that a simple null model based on the principle of maximum entropy cannot be rejected as a model for the degree distributions in most of the 115 bipartite ecological networks tested here. The model requires knowledge of the number of nodes and links in the network, but needs no other ecological information. The model cannot be rejected for 159 (69%) of the 230 degree distributions of the 115 networks tested. It performed equally well on the plant and animal degree distributions, and cannot be rejected for 81 (70%) of the 115 plant distributions and 78 (68%) of the animal distributions. There are consistent differences between the degree distributions of mutualistic and antagonistic networks, suggesting that different processes are constraining these two classes of networks. Fit to the MaxEnt null model is consistently poor among the largest mutualistic networks. Potential ecological and methodological explanations for deviations from the model suggest that spatial and temporal heterogeneity are important drivers of the structure of these large networks
The role of asymmetric interactions on the effect of habitat destruction in mutualistic networks
Plant-pollinator mutualistic networks are asymmetric in their interactions:
specialist plants are pollinated by generalist animals, while generalist plants
are pollinated by a broad involving specialists and generalists. It has been
suggested that this asymmetric ---or disassortative--- assemblage could play an
important role in determining the equal susceptibility of specialist and
generalist plants under habitat destruction. At the core of the argument lies
the observation that specialist plants, otherwise candidates to extinction,
could cope with the disruption thanks to their interaction with generalist
pollinators. We present a theoretical framework that supports this thesis. We
analyze a dynamical model of a system of mutualistic plants and pollinators,
subject to the destruction of their habitat. We analyze and compare two
families of interaction topologies, ranging from highly assortative to highly
disassortative ones, as well as real pollination networks. We found that
several features observed in natural systems are predicted by the mathematical
model. First, there is a tendency to increase the asymmetry of the network as a
result of the extinctions. Second, an entropy measure of the differential
susceptibility to extinction of specialist and generalist species show that
they tend to balance when the network is disassortative. Finally, the
disappearance of links in the network, as a result of extinctions, shows that
specialist plants preserve more connections than the corresponding plants in an
assortative system, enabling them to resist the disruption.Comment: 14 pages, 7 figure
Graviton emission in Einstein-Hilbert gravity
The five-point amplitude for the scattering of two distinct scalars with the
emission of one graviton in the final state is calculated in exact kinematics
for Einstein-Hilbert gravity. The result, which satisfies the Steinmann
relations, is expressed in Sudakov variables, finding that it corresponds to
the sum of two gauge invariant contributions written in terms of a new two
scalar - two graviton effective vertex. A similar calculation is carried out in
Quantum Chromodynamics (QCD) for the scattering of two distinct quarks with one
extra gluon in the final state. The effective vertices which appear in both
cases are then evaluated in the multi-Regge limit reproducing the well-known
result obtained by Lipatov where the Einstein-Hilbert graviton emission vertex
can be written as the product of two QCD gluon emission vertices, up to
corrections to preserve the Steinmann relations.Comment: 28 pages, LaTeX, feynmf. v2: typos corrected, reference added. Final
version to appear in Journal of High Energy Physic
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