Stabilization in a two-species chemotaxis system with logistic source

We study a system of three partial differential equations modelling the spatiotemporal behaviour of two competitive populations of biological species both of which are attracted chemotactically by the same signal substance. For a range of the parameters the system possesses a uniquely determined spatially homogeneous positive equilibrium (u?, v?) globally asymptotically stable within a certain nonempty range of the logistic growth coefficients

Mathematical analysis of a model of chemotaxis arising from morphogenesis

We consider non-negative solution of a chemotaxis system with non constant chemotaxis sensitivity function X. This system appears as a limit case of a model formorphogenesis proposed by Bollenbach et al. (Phys. Rev. E. 75, 2007).Under suitable boundary conditions, modeling the presence of a morphogen source at x=0, we prove the existence of a global and bounded weak solution using an approximation by problems where diffusion is introduced in the ordinary differential equation. Moreover,we prove the convergence of the solution to the unique steady state provided that ? is small and ? is large enough. Numerical simulations both illustrate these results and give rise to further conjectures on the solution behavior that go beyond the rigorously proved statements

Circadian rhythms regulate the environmental responses of net CO2 exchange in bean and cotton canopies

Studies on the dependence of the rates of ecosystem gas exchange on environmental parameters often rely on the up-scaling of leaf-level response curves ('bottom-up' approach), and/or the down-scaling of ecosystem fluxes ('top-down' approach), where one takes advantage of the natural diurnal covariation between the parameter of interest and photosynthesis rates. Partly independent from environmental variation, molecular circadian clocks drive ∼24 h oscillations in leaf-level photosynthesis, stomatal conductance and other physiological processes in plants under controlled laboratory conditions. If present and of sufficient magnitude at ecosystem scales, circadian regulation could lead to different results when using the bottom-up approach (where circadian regulation exerts a negligible influence over fluxes because the environment is modified rapidly) relative to the top-down approach (where circadian regulation could affect fluxes as it requires the passage of a few hours). Here we dissected the drivers of diurnal net CO2 exchange in canopies of an annual herb (bean) and of a perennial shrub (cotton) through a set of experimental manipulations to test for the importance of circadian regulation of net canopy CO2 exchange, relative to that of temperature and vapor pressure deficit, and to understand whether circadian regulation could affect the derivation of environmental flux dependencies. Contrary to conventional wisdom, we observed how circadian regulation exerted controls over net CO2 exchange that were of similar magnitude to the controls exerted by direct physiological responses to temperature and vapor pressure deficit. Diurnal patterns of net CO2 exchange could only be explained by considering effects of environmental responses combined with circadian effects. Consequently, we observed significantly different results when inferring the dependence of photosynthesis over temperature and vapor pressure deficit when using the top-down and the bottom up approaches.We remain indebted to E. Gerardeau, D. Dessauw, J. Jean, P. Prudent (Aïda CIRAD), J.-J. Drevon, C. Pernot (Eco&Sol INRA), B. Buatois, A. Rocheteau (CEFE CNRS), A. Pra, A. Mokhtar and the full Ecotron team, in particular C. Escape, for outstanding technical assistance during experiment set-up, plant cultivation and measurements. Earlier versions of the manuscript benefitted from comments by M. Dietze, B. Medlyn, R. Duursma and Y.-S. Lin. This study benefited from the CNRS human and technical resources allocated to the ECOTRONS Research Infrastructures as well as from the state allocation ‘Investissement d'Avenir’ ANR-11-INBS-0001, ExpeER Transnational Access program, Ramón y Cajal fellowships (RYC-2012-10970 to VRD and RYC-2008-02050 to JPF), the Erasmus Mundus Master Course Mediterranean Forestry and Natural Resources Management (MEDfOR) and internal grants from UWS-HIE to VRD and ZALF to AG. We thank the Associate Editor T. Vesala and two anonymous reviewers for their help to improve this manuscript

On the Keller-Segel System with External Application of Chemoattractant

Chemotaxis is the ability of microorganisms to respond to chemical signals by moving along the gradient of the chemical substance, either toward the higher concentration (positive taxis) or away from it (negative taxis)

Validation of the Abrahamic Forms of the Centrality of Religiosity Scale (CRS-5, CRS-10, and CRS-15): Evidence from Selected University Students in the Philippines

The Centrality of Religiosity Scale (CRS) is an instrument that measures the centrality, importance, or salience of religious meanings in personality. Addressing the dearth of research on the salience of religion among Filipino Christian youths, the researchers explore in this paper the degree of religiosity of selected university students and the relevance of religious beliefs in their daily life by validating the Abrahamic forms of the Centrality of Religiosity Scale (CRS-5, CRS-10, and CRS-15). This paper specifically answers the following questions: (1) What CRS version is valid for Filipino Christian youths? (2) What is the position of the religious construct-system among selected Filipino Christian university students? and (3) How does the centrality of religiosity influences the selected Filipino Christian university students’ subjective experience and behavior? Means and standard deviations were calculated for the five subscales of the centrality of religiosity for CRS-5, CRS-10, and CRS-15. The distribution of the subscale scores was also computed using measures of skewness and kurtosis. Cronbach’s α values are provided for each of the subscales to establish internal consistency. Descriptive statistics were also computed with the use of the Statistical Package for Social Science (SPSS) software version 20. Bivariate correlations are reported for all CRS-15 items. This paper established that in a predominantly Christian country such as the Philippines, the CRS-15 is suitable in measuring the centrality of religiosity among Filipino Christian youths

Validation of the Interreligious Forms of the Centrality of Religiosity Scale (CRSi-7, CRSi-14, and CRSi-20): Salience of Religion among Selected Youth in the Philippines

The presence of different religions and the freedom of people to navigate the religious space shows that religion in the Philippines is not a monolithic entity. This study validated three versions of the Centrality of Religiosity Scale (CRSi-7, -14, and -20) which propose an adequate assessment tool for the diversity of religious belief systems co-existing in Philippine society. The sample (N = 514) was drawn from the young population of the country in an online survey. Descriptive statistics and Cronbach’s alpha values were calculated for the five subscales (ideology, intellect, experience, private and public practice) of the Centrality of Religiosity Scale. The factor structure of the interreligious Centrality of Religiosity Scale was tested using confirmatory factor analysis. The results show that CRSi-7 denotes internal consistency while CRSi-14 and CRSi-20 indicate good internal consistency. Models of CRSi-7, -14, and -20 show a good global fit. Despite two models of the CRSi-20 being identical in fit, the researchers defer to the CRSi-20 model with correlated factors since it is a simpler model. All versions of the CRSi demonstrate a valid and reliable measure for the centrality of religiosity in the Philippines and support the usefulness of the CRS for the study of religiosity

Habilidades en ventas y desempeño en los asesores de la empresa Credivargas, San Martín - 2022

En la presente investigación se enunció como objetivo determinar la relación entre las habilidades en ventas y el desempeño en los asesores de la empresa mencionada. Respecto a los aspectos metodológicos, el estudio fue cuantitativo, no experimental y correlacional. La muestra estuvo constituida por 130 asesores, quienes respondieron a dos cuestionarios de elaboración propia. Los hallazgos indicaron el grado de las habilidades en ventas en asesores de la empresa muestra que el 39% calificaron a la variable como medio, en cuanto a los resultados para identificar el nivel de desempeño de los asesores de la empresa, se muestra que se encuentran en un nivel medio con un 49%. En cuanto a los resultados inferenciales vemos que todas las dimensiones de las habilidades en ventas registraron una relación con el desempeño de los asesores (p= ,000); figurando como las más destacadas la dimensión en la venta (Rho Spearman = ,781). Por otro lado, las habilidades en ventas se relacionan con el desempeño de los asesores, mediante el análisis estadístico de Rho Spearman se alcanzó un coeficiente de 0,783 (correlación positiva media alta); y un p valor igual a 0,000 (pvalor ≤ 0.01)

Implications of global pricing policies on access to innovative drugs: : the case of trastuzumab in seven Latin American countries

Background: Differential pricing, based on countries’ purchasing power, is recommended by the WHO to secure affordable medicines. However, in developing countries innovative drugs often have similar or even higher prices than in high-income countries. We evaluated the potential implications of trastuzumab global pricing policies in terms of cost-effectiveness (CE), coverage and accessibility for patients with breast cancer in Latin America (LA). Methods: A Markov model was designed to estimate life years (LYs), quality-adjusted life years (QALYs) and costs from a health care perspective. To better fit local cancer prognosis, a base case scenario using transition probabilities from clinical trials was complemented with two alternative scenarios with transition probabilities adjusted to reflect breast cancer epidemiology in each country. Findings: Incremental discounted benefits ranged from 0.87 to 1.00 LY and 0.51 to 0.60 QALY and incremental CE ratios from USD 42,104 to USD 110,283 per QALY (2012 US dollars), equivalent to 3.6 gross domestic product per capita (GDPPC) per QALY in Uruguay and to 35.5 GDPPC in Bolivia. Probabilistic sensitivity analysis showed 0% probability that trastuzumab is CE if the willingness-to-pay (WTP) threshold is one GDPPC per QALY, and remained so at three GDPPC threshold except for Chile and Uruguay (4.3% and 26.6% respectively). Trastuzumab price would need to decrease between 69.6% to 94.9% to became CE in LA. Interpretation: Although CE in other settings, trastuzumab was not CE in LA. The use of health technology assessment to prioritize resource allocation and support price negotiations is critical to making innovative drugs available and affordable in developing countries

ESTUDIO COMPARATIVO DEL EFECTO ANTICOAGULANTE IN-VITRO DEL TRIFOSFATO PENTASODICO DE GRADO TECNICO, CON EL EDTA Y EL CITRATO DE SODIO, AREQUIPA 2012

PLANTEAMIENTO TEÓRICO PRUEBAS HEMATOLÓGICAS DE RUTINA CITOMETRIA HEMÁTICA VELOCIDAD DE ERITROSEDIMENTACION PRUEBAS DE COAGULACIÓN ANTICOAGULANTES ANTICOAGULANTES QUÍMICOS IN VITRO NEO - ANTICOAGULANTES TRIFOSFATO PENTASODICO (TFPS) FOSFATOS ESTRUCTURA MOLECULAR PROPIEDADES FISICOQUÍMICAS SÍNTESIS QUÍMICA USO Y APLICACIONES EFECTO ANTICOAGULANTE CLÍNICO IN - VITRO ESTABILIDAD TOXICIDAD PLANTEAMIENTO OPERACIONAL CAMPO DE VERIFICACIÓN TÉCNICAS, INSTRUMENTOS Y MATERIALES DE VERIFICACIÓN ESTRATEGIA DE RECOLECCIÓN ESTRATEGIA PARA EL MANEJO DE RESULTADOS RESULTADO

Parameter Estimation with Maximal Updated Densities

A recently developed measure-theoretic framework solves a stochastic inverse problem (SIP) for models where uncertainties in model output data are predominantly due to aleatoric (i.e., irreducible) uncertainties in model inputs (i.e., parameters). The subsequent inferential target is a distribution on parameters. Another type of inverse problem is to quantify uncertainties in estimates of "true" parameter values under the assumption that such uncertainties should be reduced as more data are incorporated into the problem, i.e., the uncertainty is considered epistemic. A major contribution of this work is the formulation and solution of such a parameter identification problem (PIP) within the measure-theoretic framework developed for the SIP. The approach is novel in that it utilizes a solution to a stochastic forward problem (SFP) to update an initial density only in the parameter directions informed by the model output data. In other words, this method performs "selective regularization" only in the parameter directions not informed by data. The solution is defined by a maximal updated density (MUD) point where the updated density defines the measure-theoretic solution to the PIP. Another significant contribution of this work is the full theory of existence and uniqueness of MUD points for linear maps with Gaussian distributions. Data-constructed Quantity of Interest (QoI) maps are also presented and analyzed for solving the PIP within this measure-theoretic framework as a means of reducing uncertainties in the MUD estimate. We conclude with a demonstration of the general applicability of the method on two problems involving either spatial or temporal data for estimating uncertain model parameters.Comment: Code: github.com/mathematicalmichael/mud.gi