2,269 research outputs found
Determinan Upaya Pengobatan Tuberkulosis Pada Anak Di Bawah Umur 15 Tahun
One of the WHO\u27s step of TB strategy reflects the importance of the need to improve care for children with TB. However, children with TB often are neglected to cure, even in the countries with high TB incidence. Around 20 percent children estimated with TB, caused by the spreading of adult TB, and many of them without specific symptom as adult. The aim of this study is to get information about the relation between demography, socio-economic, environmental factors, vaccination status, and contact with adult TB patient, and TB treatment practice of children aged <15 years. The sample was a cross-sectional data of TB Prevalence Survey 2004 and Susenas 2004, which had been merged. The method of analysis was multivariate. The result showed that the significant variable were Sumatera region, household expenditure, BCG scars, and contact with TB patients with log-likelihood < 0.05 (p=0.000). Final model for determinant factors of TB treatment practice for children aged < 15 years were children contact with adult TB patient in the household that had risk of 1.9 times (CI 95%: 1.26-2.89) and place of living classification (Sumatera region) that had risk of 2.6 times (CI 95%: 1.65-4.01). To handle child TB cases and their treatment, there are some actions could be applied, namely: to cure every adult TB until recovery, to conduct active case finding, to educate TB patients and their family to be discipline in taking the drug, to support financial transportation to go to health facility for TB patient in poor family, and to prevent from drop out by supervising them closely
Spatial and spatio-temporal patterns in a cell-haptotaxis model
We investigate a cell-haptotaxis model for the generation of spatial and spatio-temporal patterns in one dimension. We analyse the steady state problem for specific boundary conditions and show the existence of spatially hetero-geneous steady states. A linear analysis shows that stability is lost through a Hopf bifurcation. We carry out a nonlinear multi-time scale perturbation procedure to study the evolution of the resulting spatio-temporal patterns. We also analyse the model in a parameter domain wherein it exhibits a singular dispersion relation
Cell organization in soft media due to active mechanosensing
Adhering cells actively probe the mechanical properties of their environment
and use the resulting information to position and orient themselves. We show
that a large body of experimental observations can be consistently explained
from one unifying principle, namely that cells strengthen contacts and
cytoskeleton in the direction of large effective stiffness. Using linear
elasticity theory to model the extracellular environment, we calculate optimal
cell organization for several situations of interest and find excellent
agreement with experiments for fibroblasts, both on elastic substrates and in
collagen gels: cells orient in the direction of external tensile strain, they
orient parallel and normal to free and clamped surfaces, respectively, and they
interact elastically to form strings. Our method can be applied for rational
design of tissue equivalents. Moreover our results indicate that the concept of
contact guidance has to be reevaluated. We also suggest that cell-matrix
contacts are upregulated by large effective stiffness in the environment
because in this way, build-up of force is more efficient.Comment: Revtex, 7 pages, 4 Postscript files include
Measuring site fidelity and spatial segregation within animal societies
© 2017 The Authors. Methods in Ecology and Evolution published by John Wiley & Sons Ltd on behalf of British Ecological Society. Animals often display a marked tendency to return to previously visited locations that contain important resources, such as water, food, or developing brood that must be provisioned. A considerable body of work has demonstrated that this tendency is strongly expressed in ants, which exhibit fidelity to particular sites both inside and outside the nest. However, thus far many studies of this phenomena have taken the approach of reducing an animal's trajectory to a summary statistic, such as the area it covers. Using both simulations of biased random walks, and empirical trajectories from individual rock ants, Temnothorax albipennis, we demonstrate that this reductive approach suffers from an unacceptably high rate of false negatives. To overcome this, we describe a site-centric approach which, in combination with a spatially-explicit null model, allows the identification of the important sites towards which individuals exhibit statistically significant biases. Using the ant trajectories, we illustrate how the site-centric approach can be combined with social network analysis tools to detect groups of individuals whose members display similar space-use patterns. We also address the mechanistic origin of individual site fidelity; by examining the sequence of visits to each site, we detect a statistical signature associated with a self-attracting walk – a non-Markovian movement model that has been suggested as a possible mechanism for generating individual site fidelity
The subpulse modulation properties of pulsars at 92 cm and the frequency dependence of subpulse modulation
A large sample of pulsars has been observed to study their subpulse
modulation at an observing wavelength (when achievable) of both 21 and 92 cm
using the Westerbork Synthesis Radio Telescope. In this paper we present the
92-cm data and a comparison is made with the already published 21-cm results.
We analysed 191 pulsars at 92 cm using fluctuation spectra. The sample of
pulsars is as unbiased as possible towards any particular pulsar
characteristics. For 15 pulsars drifting subpulses are discovered for the first
time and 26 of the new drifters found in the 21-cm data are confirmed. We
discovered nulling for 8 sources and 8 pulsars are found to intermittently emit
single pulses that have pulse energies similar to giant pulses. It is estimated
that at least half of the total population of pulsars have drifting subpulses
when observations with a high enough signal-to-noise ratio would be available.
It could well be that the drifting subpulse mechanism is an intrinsic property
of the emission mechanism itself, although for some pulsars it is difficult or
impossible to detect. Drifting subpulses are in general found at both
frequencies, although the chance of detecting drifting subpulses is possibly
slightly higher at 92 cm. It appears that the youngest pulsars have the most
disordered subpulses and the subpulses become more and more organized into
drifting subpulses as the pulsar ages. The correlations with the modulation
indices are argued to be consistent with the picture in which the radio
emission can be divided in a drifting subpulse signal plus a quasi-steady
signal which becomes, on average, stronger at high observing frequencies. The
measured values of P3 at the two frequencies are highly correlated, but there
is no evidence for a correlation with other pulsar parameters.Comment: 30 pages, 10 figures, accepted for publication in A&A, astro-ph
version is missing 191 figures due to file size restrictions. Please download
the appendix from
http://www.astron.nl/~stappers/wiki/doku.php?id=resources:publication
Spatio-temporal patterns in a mechanical model for mesenchymal morphogenesis
We present an in-depth study of spatio-temporal patterns in a simplified version of a mechanical model for pattern formation in mesenchymal morphogenesis. We briefly motivate the derivation of the model and show how to choose realistic boundary conditions to make the system well-posed. We firstly consider one-dimensional patterns and carry out a nonlinear perturbation analysis for the case where the uniform steady state is linearly unstable to a single mode. In two-dimensions, we show that if the displacement field in the model is represented as a sum of orthogonal parts, then the model can be decomposed into two sub-models, only one of which is capable of generating pattern. We thus focus on this particular sub-model. We present a nonlinear analysis of spatio-temporal patterns exhibited by the sub-model on a square domain and discuss mode interaction. Our analysis shows that when a two-dimensional mode number admits two or more degenerate mode pairs, the solution of the full nonlinear system of partial differential equations is a mixed mode solution in which all the degenerate mode pairs are represented in a frequency locked oscillation
NF kappa B induces overexpression of bovine FcRn: a novel mechanism that further contributes to the enhanced immune response in genetically modified animals carrying extra copies of FcRn
Among the many functions of the neonatal Fc receptor (FcRn) for
IgG, it binds to IgG-opsonized antigen complexes and propagates
their traffic into lysosomes where antigen processing occurs. We
previously reported that transgenic (Tg) mice and rabbits that
carry multiple copies and overexpress FcRn have augmented
humoral immune responses. Nuclear factor-kappa B (NFκB) is a
critical molecule in the signaling cascade in the immune
response. NFκB induces human FcRn expression and our previous in
silico analysis suggested NFκB binding sites in the promoter
region of the bovine (b) FcRn α-chain gene (FCGRT). Here, we
report the identification of three NFκB transcription binding
sites in the promoter region of this gene using luciferase
reporter gene technology, electromobility shift assay and
supershift analysis. Stimulation of primary bovine endothelial
cells with the Toll like receptor-4 ligand lipopolysaccharide
(LPS), which mediates its effect via NFκB, resulted in rapid
upregulation of the bFcRn expression and a control gene, bovine
E-selectin. This rapid bFcRn gene induction was also observed in
the spleen of bFcRn Tg mice treated with intraperitoneally
injected LPS, analyzed by northern blot analysis. Finally, NFκB-
mediated bFcRn upregulation was confirmed at the protein level
in macrophages isolated from the bFcRn Tg mice using flow
cytometry with a newly developed FcRn specific monoclonal
antibody that does not cross-react with the mouse FcRn. We
conclude that NFκB regulates bFcRn expression and thus optimizes
its functions, e.g., in the professional antigen presenting
cells, and contributes to the much augmented humoral immune
response in the bFcRn Tg mice
Towards an integrated experimental-theoretical approach for assessing the mechanistic basis of hair and feather morphogenesis
In his seminal 1952 paper, ‘The Chemical Basis of Morphogenesis’, Alan Turing lays down a milestone in the application of theoretical approaches to understand complex biological processes. His deceptively simple demonstration that a system of reacting and diffusing chemicals could, under certain conditions, generate spatial patterning out of homogeneity provided an elegant solution to the problem of how one of nature's most intricate events occurs: the emergence of structure and form in the developing embryo. The molecular revolution that has taken place during the six decades following this landmark publication has now placed this generation of theoreticians and biologists in an excellent position to rigorously test the theory and, encouragingly, a number of systems have emerged that appear to conform to some of Turing's fundamental ideas. In this paper, we describe the history and more recent integration between experiment and theory in one of the key models for understanding pattern formation: the emergence of feathers and hair in the skins of birds and mammals
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