894 research outputs found
Modeling the Role of the Cell Cycle in Regulating Proteus mirabilis Swarm-Colony Development
We present models and computational results which indicate that the spatial
and temporal regularity seen in Proteus mirabilis swarm-colony development is
largely an expression of a sharp age of dedifferentiation in the cell cycle
from motile swarmer cells to immotile dividing cells (also called swimmer or
vegetative cells.) This contrasts strongly with reaction-diffusion models of
Proteus behavior that ignore or average out the age structure of the cell
population and instead use only density-dependent mechanisms. We argue the
necessity of retaining the explicit age structure, and suggest experiments that
may help determine the underlying mechanisms empirically. Consequently, we
advocate Proteus as a model organism for a multiscale understanding of how and
to what extent the life cycle of individual cells affects the macroscopic
behavior of a biological system
Models of Microbial Dormancy in Biofilms and Planktonic Cultures
We present models of dormancy in a planktonic culture and in biofilm, and
examine the relative advantage of short dormancy versus long dormancy times in
each case. Simulations and analyses indicate that in planktonic batch cultures
and in chemostats, live biomass is maximized by the fastest possible exit from
dormancy. The lower limit of time to reawakening is thus perhaps governed by
physiological, biochemical or other constraints within the cells. In biofilm we
see that the slower waker has a defensive advantage over the fast waker due to
a larger amount of dormant biomass, without an appreciable difference in total
live biomass. Thus it would seem that typical laboratory culture conditions can
be unrepresentative of the natural state. We discuss the computational methods
developed for this work
A methodology for long-range prediction of air transportation
A framework and methodology for long term projection of demand for aviation fuels is presented. The approach taken includes two basic components. The first was a new technique for establishing the socio-economic environment within which the future aviation industry is embedded. The concept utilized was a definition of an overall societal objective for the very long run future. Within a framework so defined, a set of scenarios by which the future will unfold are then written. These scenarios provide the determinants of the air transport industry operations and accordingly provide an assessment of future fuel requirements. The second part was the modeling of the industry in terms of an abstracted set of variables to represent the overall industry performance on a macro scale. The model was validated by testing the desired output variables from the model with historical data over the past decades
A Unified Term for Directed and Undirected Motility in Collective Cell Invasion
In this paper we develop mathematical models for collective cell motility.
Initially we develop a model using a linear diffusion-advection type equation
and fit the parameters to data from cell motility assays. This approach is
helpful in classifying the results of cell motility assay experiments. In
particular, this model can determine degrees of directed versus undirected
collective cell motility. Next we develop a model using a nonlinear diffusion
term that is able capture in a unified way directed and undirected collective
cell motility. Finally we apply the nonlinear diffusion approach to a problem
in tumor cell invasion, noting that neither chemotaxis or haptotaxis are
present in the system under consideration in this article
A Multiscale Model of Biofilm as a Senescence-Structured Fluid
We derive a physiologically structured multiscale model for biofilm
development. The model has components on two spatial scales, which induce
different time scales into the problem. The macroscopic behavior of the system
is modeled using growth-induced flow in a domain with a moving boundary.
Cell-level processes are incorporated into the model using a so-called
physiologically structured variable to represent cell senescence, which in turn
affects cell division and mortality. We present computational results for our
models which shed light on modeling the combined role senescence and the
biofilm state play in the defense strategy of bacteria
PERANCANGAN KOMIK WEBTOON MELALUI KISAH FABEL AL-QURAN SEBAGAI MEDIA PEMBENTUKAN KARAKTER
AbstraKKetersediaan buku di Indonesia dari segi kualitas dan kuantitas masih sangat minim beredar. Padahal buku yang berkualitas merupakan salah satu sarana yang dapat membantu pembentukan karakter karena membangun nilai intelektual, emosional, sosial dan moral. Salah satu contohnya adalah buku bacaan yang dikreasikan melalui sastra berbentuk fabel dengan unsur edukasi dan moral yang terkandung didalamnya, yang umumnya berkaitan erat dengan ajaran agama seperti dalam agama Islam pada al-quran dalam surat An-Naml (semut). Namun jumlah pengkajian pembentukan karakter berbasis cerita fabel al-quran masih terbatas. Bertepatan dengan perkembangan zaman dan teknologi saat ini komik tidak hanya berbentuk media konvensional tetapi juga berbentuk digital contohnya platform komik digital yang dapat diakses dengan mudah dan gratis seperti Webtoon. Hal inilah yang melatarbelakangi perancangan komik webtoon melalui kisah fabel al-quran sebagai media pembentukan karakter. Penelitian yang digunakan menggunakan metode kualitatif dengan data yang diperoleh melalui studi pustaka dan wawancara serta menggunakan metode analisis matriks dan SWOT. Dengan adanya perancangan ini diharapkan dapat meningkatkan kualitas buku bahan bacaan yang mudah dijangkau oleh masyarakat Indonesia.Kata kunci: Fabel Al-Quran, pembentukan karakter, komik webtoon
Deep Learning Model With Adaptive Regularization for EEG-Based Emotion Recognition Using Temporal and Frequency Features
Since EEG signal acquisition is non-invasive and portable, it is convenient to be used for different applications. Recognizing emotions based on Brain-Computer Interface (BCI) is an important active BCI paradigm for recognizing the inner state of persons. There are extensive studies about emotion recognition, most of which heavily rely on staged complex handcrafted EEG feature extraction and classifier design. In this paper, we propose a hybrid multi-input deep model with convolution neural networks (CNNs) and bidirectional Long Short-term Memory (Bi-LSTM). CNNs extract time-invariant features from raw EEG data, and Bi-LSTM allows long-range lateral interactions between features. First, we propose a novel hybrid multi-input deep learning approach for emotion recognition from raw EEG signals. Second, in the first layers, we use two CNNs with small and large filter sizes to extract temporal and frequency features from each raw EEG epoch of 62-channel 2-s and merge with differential entropy of EEG band. Third, we apply the adaptive regularization method over each parallel CNN’s layer to consider the spatial information of EEG acquisition electrodes. The proposed method is evaluated on two public datasets, SEED and DEAP. Our results show that our technique can significantly improve the accuracy in comparison with the baseline where no adaptive regularization techniques are used
Modeling the Effects of Multiple Myeloma on Kidney Function
Multiple myeloma (MM), a plasma cell cancer, is associated with many health
challenges, including damage to the kidney by tubulointerstitial fibrosis. We
develop a mathematical model which captures the qualitative behavior of the
cell and protein populations involved. Specifically, we model the interaction
between cells in the proximal tubule of the kidney, free light chains, renal
fibroblasts, and myeloma cells. We analyze the model for steady-state solutions
to find a mathematically and biologically relevant stable steady-state
solution. This foundational model provides a representation of dynamics between
key populations in tubulointerstitial fibrosis that demonstrates how these
populations interact to affect patient prognosis in patients with MM and renal
impairment.Comment: Included version of model without tumor with steady-state analysis,
corrected equations for free light chains and renal fibroblasts in model with
tumor to reflect steady-state analysis, updated abstract, updated and added
reference
Computational Methods and Results for Structured Multiscale Models of Tumor Invasion
We present multiscale models of cancer tumor invasion with components at the
molecular, cellular, and tissue levels. We provide biological justifications
for the model components, present computational results from the model, and
discuss the scientific-computing methodology used to solve the model equations.
The models and methodology presented in this paper form the basis for
developing and treating increasingly complex, mechanistic models of tumor
invasion that will be more predictive and less phenomenological. Because many
of the features of the cancer models, such as taxis, aging and growth, are seen
in other biological systems, the models and methods discussed here also provide
a template for handling a broader range of biological problems
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