276 research outputs found
Discrete Evolutionary Population Models: A New Approach
In this paper, we apply a new approach to a special class of discrete time evolution models and establish a solid mathematical foundation to analyse them. We propose new single and multi-species evolutionary competition models using the evolutionary game theory that require a more advanced mathematical theory to handle effectively. A key feature of this new approach is to consider the discrete models as non-autonomous difference equations. Using the powerful tools and results developed in our recent work [E. D\u27Aniello and S. Elaydi, The structure of ω-limit sets of asymptotically non-autonomous discrete dynamical systems, Discr. Contin. Dyn. Series B. 2019 (to appear).], we embed the non-autonomous difference equations in an autonomous discrete dynamical systems in a higher dimension space, which is the product space of the phase space and the space of the functions defining the non-autonomous system. Our current approach applies to two scenarios. In the first scenario, we assume that the trait equations are decoupled from the equations of the populations. This requires specialized biological and ecological assumptions which we clearly state. In the second scenario, we do not assume decoupling, but rather we assume that the dynamics of the trait is known, such as approaching a positive stable equilibrium point which may apply to a much broader evolutionary dynamics
Hydatidose du rachis cervical : A propos d’un cas
L’hydatidose intéresse l’os dans 0,5 à 2 % des cas, dont 44 % de localisations au niveau rachidien. L’étage cervical est la moins fréquente des localisations rachidiennes. Cette atteinte est grave par le risque de compression médullaire haute, et surtout par son caractère récidivant. Les auteurs présentent l’observation d’un jeune patient admis pour une tétraplégie progressive, due à une hydatidose vertébro-médullaire cervicale ; son diagnostic a été évoquée sur l’imagerie par résonance magnétique et confirmée par l’étude anatomopathologique
Kyste epidermoïde du quatrieme ventricule : a propos d’un cas
Les kystes épidermoïdes sont des tumeurs bénignes rares développées à partir d’inclusions ectodermiques. Ils siègent habituellement au niveau de l’angle ponto-cérébelleux, la région para-sellaire et la fosse temporale. Leur siège au niveau du quatrième ventricule est inhabituel. Nous rapportons le cas d’une jeune patiente de 44 ans admise pour un syndrome d’hypertension intracrânienne associé à des troubles de la marche. Le diagnostic de kyste épidermoïde du V4 fut évoqué sur les données de l’IRM puis confirmé en per opératoire et en histologie. L’exérèse chirurgicale a été subtotale en raison d’une adhérence de la capsule à la partie supérieure du plancher du V4. Après un recul de 18 mois, la patiente ne manifeste aucun signe de ré-évolution tumorale.Mots clés : chirurgie, IRM de diffusion, kyste épidermoïde, quatrième ventricl
Fetal surveillance of anti-Ro/anti-La affected pregnancies: is there a consensus? Results of an international survey
Geometry effect of irrigation storage basin on particles removal efficiency: A computational fluid dynamics study
Drip irrigation requires the use of high quality water to avoid emitters clogging and the wear of hydraulic pumps and sand filters. Investing in an irrigation storage basin is not only beneficial to meet crop water requirements but also to remove naturally suspended solids by sedimentation. However, the design and sizing of an irrigation storage basin is usually based only on irrigation water needs and plant area without taking into consideration that the shape and size of the basin can also have an effect on the removal efficiency. Moreover, storage volume can be achieved by different combinations of length, width and depth. The present paper studies the effect of irrigation storage basin geometry on its performance in settling down suspended sediments. The methodology adopted in this study is based on the computational fluid dynamics using ANSYS Fluent. Specific experimental results taken from the literature are used to confirm the reliability of the numerical simulations to describe the flow field. First, a parametric study is executed in order to identify the effect of each basin dimensions. Then, trap efficiency is calculated for twenty basins having the same capacity of storage and different geometries in order to select the optimal dimensions. Results show that the removal efficiency is very sensitive to basin size, especially to its depth and length. Nevertheless, for a specific capacity of storage, two different dimensionless parameters can be used to select the optimal size: the length to depth ratio and the length to width ratio. In cases, where the depth value is required due to soil type or land surface, the second ratio can be used
The KATRIN Pre-Spectrometer at reduced Filter Energy
The KArlsruhe TRItium Neutrino experiment, KATRIN, will determine the mass of
the electron neutrino with a sensitivity of 0.2 eV (90% C.L.) via a measurement
of the beta-spectrum of gaseous tritium near its endpoint of E_0 =18.57 keV. An
ultra-low background of about b = 10 mHz is among the requirements to reach
this sensitivity. In the KATRIN main beam-line two spectrometers of MAC-E
filter type are used in a tandem configuration. This setup, however, produces a
Penning trap which could lead to increased background. We have performed test
measurements showing that the filter energy of the pre-spectrometer can be
reduced by several keV in order to diminish this trap. These measurements were
analyzed with the help of a complex computer simulation, modeling multiple
electron reflections both from the detector and the photoelectric electron
source used in our test setup.Comment: 22 pages, 12 figure
Double aortic arch with double aneuploidy—rare anomaly in combined Down and Klinefelter syndrome
A 14-month-old boy with double aneuploidy and a double aortic arch suffered from frequently recurrent severe feeding and respiratory problems. Chromosomal analysis showed a 48,XXY + 21 karyotype: a double aneuploidy of Down syndrome (DS) and Klinefelter syndrome (KS). Only four cases of double aneuploidy (DS + KS) associated with congenital heart defects have been published of which none had a double aortic arch. Our case report should draw attention to the possibility of a double aortic arch in patients with severe feeding and respiratory problems and a double aneuploidy
Nature inspired meta-heuristic algorithms for deep learning: recent progress and novel perspective
Deep learning is presently attracting extra ordinary attention from
both the industry and the academia. The application of deep learning in computer
vision has recently gain popularity. The optimization of deep learning models
through nature inspired algorithms is a subject of debate in computer science. The
application areas of the hybrid of natured inspired algorithms and deep learning
architecture includes: machine vision and learning, image processing, data science,
autonomous vehicles, medical image analysis, biometrics, etc. In this paper,
we present recent progress on the application of nature inspired algorithms in
deep learning. The survey pointed out recent development issues, strengths,
weaknesses and prospects for future research. A new taxonomy is created based
on natured inspired algorithms for deep learning. The trend of the publications in
this domain is depicted; it shows the research area is growing but slowly. The
deep learning architectures not exploit by the nature inspired algorithms for
optimization are unveiled. We believed that the survey can facilitate synergy
between the nature inspired algorithms and deep learning research communities.
As such, massive attention can be expected in a near future
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