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 Acta Biotheoretica   [SJR: 0.419]   [H-I: 25]   [5 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 1572-8358 - ISSN (Online) 0001-5342    Published by Springer-Verlag  [2353 journals]
• The Role of Hyalomma Truncatum on the Dynamics of Rift Valley Fever:
Insights from a Mathematical Epidemic Model
• Authors: Sansao A. Pedro; Shirley Abelman; Henri E. Z. Tonnang
Pages: 1 - 36
Abstract: To date, our knowledge of Rift Valley fever (RVF) disease spread and maintenance is still limited, as flooding, humid weather and presence of biting insects such as mosquitoes, have not completely explained RVF outbreaks. We propose a model that includes livestock, mosquitoes and ticks compartments structured according to their questing and feeding behaviour in order to study the possible role of ticks on the dynamics of RVF. To quantify disease transmission at the initial stage of the epidemic, we derive an explicit formula of the basic reproductive number, $$R_0$$ . Using the concept of Metzler matrix, we state necessary conditions for global asymptotic stability of the disease-free equilibrium. Results suggest that although host-ticks interactions may serve as disease reservoirs or disease amplifiers, the Aedes reproductive number should be kept under unity if disease post-epizootics activities are to be controlled. Results of both local and global sensitivity analysis of selected model parameters indicate that $$R_0$$ is more sensitive to the ticks attachment and detachment rates, probability of transmission from ticks to host and from host to ticks, length of infection in livestock and ticks death rate. Furthermore, when comparing the mean value of $$R_0$$ with that from previous studies which did not include ticks we found that our $$R_0$$ is very much larger resulting in an increase in the exponential phase of an outbreak. These findings suggest that if ticks are capable of transmitting the virus, they may be contributing to disease outbreaks and endemicity.
PubDate: 2017-03-01
DOI: 10.1007/s10441-016-9285-0
Issue No: Vol. 65, No. 1 (2017)

• SMT and TOFT Integrable After All: A Reply to Bizzarri and Cucina
• Authors: Baptiste Bedessem; Stphanie Ruphy
Pages: 81 - 85
Abstract: In a previous paper recently published in this journal, we argue that the two main theories of carcinogenesis (SMT and TOFT) should be considered as compatible, at the metaphysical, epistemological and biological levels. In a reply to our contribution, Bizzarri and Cucina claim we are wrong since SMT and TOFT are opposite and incompatible paradigms. Here, we show that their arguments are not satisfactory. Indeed, the authors go through the same mistakes that we already addressed. In particular, they confuse reductionism, as an ontological frame, and genetic determinism, as a causal pathway. Beside, they make an inadequate use of the Kuhnian notion of paradigm shift. Finally, we confirm our previous conclusion: there is no strong argument to totally abandon the somatic mutation theory. It describes a partial causal pathway, compatible with the one proposed by TOFT.
PubDate: 2017-03-01
DOI: 10.1007/s10441-016-9286-z
Issue No: Vol. 65, No. 1 (2017)

• On Scott-Phillips’ General Account of Communication
• Authors: Ronald J. Planer
Abstract: The purpose of this paper is to critically engage with a recent attempt by Thom Scott-Phillips to offer a general account of communication. As a general account, it is intended to apply equally well to both non-human and human interactions which are prima facie communicative in character. However, so far, Scott-Phillips has provided little detail regarding how his account is supposed to apply to the latter set of cases. After presenting what I take to be the most plausible way of filling in those details, I argue that his account would appear to be too narrow: it (minimally) fails to capture a range of human interactions which strike us as instances of communication. To wit, these are cases in which some but not all of the information an act is designed to convey to a reactor actually reaches that reactor. An alternative account incorporating Scott-Phillips’ main insights is then sketched, and it is suggested that this account, or something like it, would accommodate the full range of non-human and human interactions that are intuitively communicative.
PubDate: 2017-08-08
DOI: 10.1007/s10441-017-9313-8

• Microscale Gaseous Slip Flow in the Insect Trachea and Tracheoles
• Authors: S. M. Simelane; S. Abelman; F. D. Duncan
Abstract: An analytical investigation into compressible gas flow with slight rarefactions through the insect trachea and tracheoles during the closed spiracle phase is undertaken, and a complete set of asymptotic analytical solutions is presented. We first obtain estimates of the Reynolds and Mach numbers at the channel terminal ends where the tracheoles directly deliver respiratory gases to the cells, by comparing the magnitude of the different forces in the compressible gas flow. The 2D Navier–Stokes equations with a slip boundary condition are used to investigate compressibility and rarefied effects in the trachea and tracheoles. Expressions for the velocity components, pressure gradients and net flow inside the trachea are then presented. Numerical simulations of the tracheal compressible flow are performed to validate the analytical results from this study. This work extends previous work of Arkilic et al. (J Microelectromech Syst 6(2):167–178, 1997) on compressible flows through a microchannel. Novel devices for microfluidic compressible flow transport may be invented from results obtained in this study.
PubDate: 2017-07-11
DOI: 10.1007/s10441-017-9312-9

• What do Biologists Make of the Species Problem?
• Authors: Bruno Pušić; Pavel Gregorić; Damjan Franjević
Abstract: The concept of species is one of the core concepts in biology and one of the cornerstones of evolutionary biology, yet it is rife with conceptual problems. Philosophers of biology have been discussing the concept of species for decades, and in doing so they sometimes appeal to the views of biologists. However, their statements as to what biologists think are seldom supported by empirical data. In order to investigate what biologists actually think about the key issues related to the problem of species, we have conducted a survey on the sample of 193 biologists from the population of biologists from over 150 biology departments at universities in the US and the EU. This article presents and discusses the results of the survey. Some results confirm and others falsify the reiterated statements of philosophers of biology as to what biologists think, but all results we obtained should be informative and relevant for future discussions of the problem of species.
PubDate: 2017-05-13
DOI: 10.1007/s10441-017-9311-x

• Establishing a Framework for a Natural Area Taxonomy
• Authors: Malte C. Ebach; Bernard Michaux
Abstract: The identification of areas of endemism is essential in building an area classification, but plays little role in how natural areas are discovered. Rather area monophyly, derived from cladistics, is essential in the discovery of natural area classifications or area taxonomy. We propose Area Taxonomy to be a new sub-discipline of historical biogeography, one that can be revised and debated, and which has its own area nomenclature. Separately to area taxonomy, we outline how natural areas may be discovered by transcribing the concepts of homology and monophyly from biological systematics to historical biogeography, in the form of area homologues, area homologies and area monophyly.
PubDate: 2017-05-10
DOI: 10.1007/s10441-017-9310-y

• Asymptotic Behavior of a Chemostat Model with Constant Recycle Sludge
Concentration
• Authors: Mohamed Amine Hamra; Karim Yadi
Abstract: In this work, we study a several species aerobic chemostat model with constant recycle sludge concentration in continuous culture. We reduce the number of parameters by considering a dimensionless model. First, the existence of a global positive uniform attractor for the model with different removal rates is proved using the theory of dissipative dynamical systems. Hence, we investigate the asymptotic behavior of the model under small perturbations using methods of singular perturbation theory and we prove that, in the case of two species in competition, the unique equilibrium which is positive is globally asymptotically stable. Finally, we establish the link between the open problem of the chemostat with different removal rates and monotone functional responses, and our model when two species compete on the same nutrient. We give some numerical simulations to illustrate the results.
PubDate: 2017-05-04
DOI: 10.1007/s10441-017-9309-4

• Skewed Exposure to Environmental Antigens Complements Hygiene Hypothesis
in Explaining the Rise of Allergy
• Authors: Wilfried Allaerts; Tse Wen Chang
Abstract: The Hygiene Hypothesis has been recognized as an important cornerstone to explain the sudden increase in the prevalence of asthma and allergic diseases in modernized culture. The recent epidemic of allergic diseases is in contrast with the gradual implementation of Homo sapiens sapiens to the present-day forms of civilization. This civilization forms a gradual process with cumulative effects on the human immune system, which co-developed with parasitic and commensal Helminths. The clinical manifestation of this epidemic, however, became only visible in the second half of the twentieth century. In order to explain these clinical effects in terms of the underlying IgE-mediated reactions to innocuous environmental antigens, the low biodiversity of antigens in the domestic environment plays a pivotal role. The skewing of antigen exposure as a cumulative effect of reducing biodiversity in the immediate human environment as well as in changing food habits, provides a sufficient and parsimonious explanation for the rise in allergic diseases in a highly developed and helminth-free modernized culture. Socio-economic tendencies that incline towards a further reduction of environmental biodiversity may provide serious concern for future health. This article explains that the “Hygiene Hypothesis”, the “Old Friends Hypothesis”, and the “Skewed Antigen Exposure Hypothesis” are required to more fully explain the rise of allergy in modern societies.
PubDate: 2017-03-24
DOI: 10.1007/s10441-017-9306-7

• Stability of a Stochastic Model of an SIR Epidemic with Vaccination
• Authors: P. J. Witbooi
Abstract: We prove almost sure exponential stability for the disease-free equilibrium of a stochastic differential equations model of an SIR epidemic with vaccination. The model allows for vertical transmission. The stochastic perturbation is associated with the force of infection and is such that the total population size remains constant in time. We prove almost sure positivity of solutions. The main result concerns especially the smaller values of the diffusion parameter, and describes the stability in terms of an analogue $$\mathcal{R}_\sigma$$ of the basic reproduction number $$\mathcal{R}_0$$ of the underlying deterministic model, with $$\mathcal{R}_\sigma \le \mathcal{R}_0$$ . We prove that the disease-free equilibrium is almost sure exponentially stable if $$\mathcal{R}_\sigma <1$$ .
PubDate: 2017-03-21
DOI: 10.1007/s10441-017-9308-5

• External Noise and External Signal Induced Transition of Gene Switch and
Coherence Resonance in the Genetic Regulatory System
• Authors: Jian-Cheng Shi; Min Luo; Tao Dong; Chu-Sheng Huang
Abstract: The transition of gene switch induced by external noises (multiplicative external noise and additive external noise) and external signals is investigated in the genetic regulatory system. Results show that the state-to-state transition of gene switch as well as resonant behaviors, such as the explicit coherence resonance (ECR), implicit coherence resonance (ICR) and control parameter coherence biresonance (CPCBR), can appear when noises are injected into the genetic regulatory system. The ECR is increased with the increase of the control parameter value when starting from the supercritical Hopf bifurcation parameter point, and there exists a critical control parameter value for the occurrence of ECR. However, the ICR is decreased as the control parameter value is increased when starting from the subcritical Hopf bifurcation point. In particular, the coherence of ECR is higher and more sensitive to noise than that of ICR. When an external signal is introduced into the system, the enhancement or suppression of the CPCBR and the number of peaks strongly depend on the frequency and amplitude of the external signal. Furthermore, the gene regulation system can selectively enhance or decrease the noise-induced oscillation signals at preferred frequency and amplitude of an external signal.
PubDate: 2017-03-17
DOI: 10.1007/s10441-017-9307-6

• Mapping Biological Transmission: An Empirical, Dynamical, and Evolutionary
Approach
• Authors: Francesca Merlin; Livio Riboli-Sasco
Abstract: The current debate over extending inheritance and its evolutionary impact has focused on adding new categories of non-genetic factors to the classical transmission of DNA, and on trying to redefine inheritance. Transmitted factors have been mainly characterized by their directions of transmission (vertical, horizontal, or both) and the way they store variations. In this paper, we leave aside the issue of defining inheritance. We rather try to build an evolutionary conceptual framework that allows for tracing most, if not all forms of transmission and makes sense of their different tempos and modes. We discuss three key distinctions that should in particular be the targets of theoretical and empirical investigation, and try to assess the interplay among them and evolutionary dynamics. We distinguish two channels of transmission (channel 1 and channel 2), two measurements of the temporal dynamics of transmission, respectively across and within generations (durability and residency), and two types of transmitted factors according to their evolutionary relevance (selectively relevant and neutral stable factors). By implementing these three distinctions we can then map different forms of transmission over a continuous space describing the combination of their varying dynamical features. While our aim is not to provide yet another model of inheritance, putting together these distinctions and crossing them, we manage to offer an inclusive conceptual framework of transmission, grounded in empirical observation, and coherent with evolutionary theory. This interestingly opens possibilities for qualitative and quantitative analyses, and is a necessary step, we argue, in order to question the interplay between the dynamics of evolution and the dynamics of multiple forms of transmission.
PubDate: 2017-02-14
DOI: 10.1007/s10441-017-9305-8

• Erratum to: Exploring Darwinian Worlds: From Darwin to the Extended
Synthesis
• Authors: Elena Casetta; Andrea Borghini
PubDate: 2017-02-06
DOI: 10.1007/s10441-017-9304-9

• Dual Causality and the Autonomy of Biology
• Authors: Walter J. Bock
Abstract: Ernst Mayr’s concept of dual causality in biology with the two forms of causes (proximate and ultimate) continues to provide an essential foundation for the philosophy of biology. They are equivalent to functional (=proximate) and evolutionary (=ultimate) causes with both required for full biological explanations. The natural sciences can be classified into nomological, historical nomological and historical dual causality, the last including only biology. Because evolutionary causality is unique to biology and must be included for all complete biological explanations, biology is autonomous from the physical sciences.
PubDate: 2017-01-02
DOI: 10.1007/s10441-016-9303-2

• On the Role of Imitation on Adolescence Methamphetamine Abuse Dynamics
• Authors: J. Mushanyu; F. Nyabadza; G. Muchatibaya; A. G. R. Stewart
Abstract: Adolescence methamphetamine use is an issue of considerable concern due to its correlation with later delinquency, divorce, unemployment and health problems. Understanding how adolescents initiate methamphetamine abuse is important in developing effective prevention programs. We formulate a mathematical model for the spread of methamphetamine abuse using nonlinear ordinary differential equations. It is assumed that susceptibles are recruited into methamphetamine use through imitation. An epidemic threshold value, $${\mathcal {R}}_a$$ , termed the abuse reproduction number, is proposed and defined herein in the drug-using context. The model is shown to exhibit the phenomenon of backward bifurcation. This means that methamphetamine problems may persist in the population even if $${\mathcal {R}}_a$$ is less than one. Sensitivity analysis of $${\mathcal {R}}_a$$ was performed to determine the relative importance of different parameters in methamphetamine abuse initiation. The model is then fitted to data on methamphetamine users less than 20 years old reporting methamphetamine as their primary substance of abuse in the treatment centres of Cape Town and parameter values that give the best fit are chosen. Results show that the proportion of methamphetamine users less than 20 years old reporting methamphetamine as their primary substance of abuse will continue to decrease in Cape Town of South Africa. The results suggest that intervention programs targeted at reducing adolescence methamphetamine abuse, are positively impacting methamphetamine abuse.
PubDate: 2016-12-18
DOI: 10.1007/s10441-016-9302-3

• Discrete Mesh Approach in Morphogenesis Modelling: the Example of
Gastrulation
• Abstract: Morphogenesis is a general concept in biology including all the processes which generate tissue shapes and cellular organizations in a living organism. Many hybrid formalizations (i.e., with both discrete and continuous parts) have been proposed for modelling morphogenesis in embryonic or adult animals, like gastrulation. We propose first to study the ventral furrow invagination as the initial step of gastrulation, early stage of embryogenesis. We focus on the study of the connection between the apical constriction of the ventral cells and the initiation of the invagination. For that, we have created a 3D biomechanical model of the embryo of the Drosophila melanogaster based on the finite element method. Each cell is modelled by an elastic hexahedron contour and is firmly attached to its neighbouring cells. A uniform initial distribution of elastic and contractile forces is applied to cells along the model. Numerical simulations show that invagination starts at ventral curved extremities of the embryo and then propagates to the ventral medial layer. Then, this observation already made in some experiments can be attributed uniquely to the specific shape of the embryo and we provide mechanical evidence to support it. Results of the simulations of the “pill-shaped” geometry of the Drosophila melanogaster embryo are compared with those of a spherical geometry corresponding to the Xenopus lævis embryo. Eventually, we propose to study the influence of cell proliferation on the end of the process of invagination represented by the closure of the ventral furrow.
PubDate: 2016-11-16
DOI: 10.1007/s10441-016-9301-4

• Interactions Between the Cross-Shore Structure of Small Pelagic Fish
Population, Offshore Industrial Fisheries and Near Shore Artisanal
Fisheries: A Mathematical Approach
• Authors: Rachid Mchich; Timothée Brochier; Pierre Auger; Patrice Brehmer
Abstract: This work presents a mathematical model describing the interactions between the cross-shore structure of small pelagic fish population an their exploitation by coastal and offshore fisheries. The complete model is a system of seven ODE’s governing three stocks of small pelagic fish population moving and growing between three zones. Two types of fishing fleets are inter-acting with the fish population, industrial boats, constrained to offshore area, and artisanal boats, operating from the shore. Two time scales were considered and we use aggregation methods that allow us to reduce the dimension of the model and to obtain an aggregated model, which is a four dimension one. The analysis of the aggregated model is performed. We discuss the possible equilibriums and their meaning in terms of fishery management. An interesting equilibrium state can be obtained for which we can expect coexistence and a stable equilibrium state between fish stocks and fishing efforts. Some identification parameters are also given in the discussion part of the model.
PubDate: 2016-10-26
DOI: 10.1007/s10441-016-9299-7

• Recursive Model Identification for the Evaluation of Baroreflex
Sensitivity
• Authors: Virginie Le Rolle; Alain Beuchée; Jean-Paul Praud; Nathalie Samson; Patrick Pladys; Alfredo I. Hernández
Abstract: A method for the recursive identification of physiological models of the cardiovascular baroreflex is proposed and applied to the time-varying analysis of vagal and sympathetic activities. The proposed method was evaluated with data from five newborn lambs, which were acquired during injection of vasodilator and vasoconstrictors and the results show a close match between experimental and simulated signals. The model-based estimation of vagal and sympathetic contributions were consistent with physiological knowledge and the obtained estimators of vagal and sympathetic activities were compared to traditional markers associated with baroreflex sensitivity. High correlations were observed between traditional markers and model-based indices.
PubDate: 2016-10-18
DOI: 10.1007/s10441-016-9295-y

• A Mathematical Model for Alternation of Polygamy and Parthenogenesis:
Stability Versus Efficiency and Analogy with Parasitism
• Authors: Evariste Sanchez-Palencia; Philippe Lherminier; Jean-Pierre Françoise
Abstract: The present work is a contribution to the understanding of the sempiternal problem of the “burden of factor two” implied by sexual reproduction versus asexual one, as males are energy consumers not contributing to the production of offspring. We construct a deterministic mathematical model in population dynamics where a species enjoys both sexual and parthenogenetic capabilities of reproduction and lives on a limited resource. We then show how polygamy implies instability of a parthenogenetic population with a small number of sexually born males. This instability implies evolution of the system towards an attractor involving both (sexual and asexual) populations (which does not imply optimality of the population). We also exhibit the analogy with a parasite/host system.
PubDate: 2016-10-13
DOI: 10.1007/s10441-016-9293-0

• Exploring Darwinian Worlds: From Darwin to the Extended Synthesis
• PubDate: 2016-10-03
DOI: 10.1007/s10441-016-9289-9

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