The response of Musa cultivar root systems to a tree shade gradient

Poster presented at Tropentag 2011 - Development on the Margin. Bonn (Germany), 3-7 Oct 2011

Barriers to Pursuing STEM-Related Careers: Perceptions of Hispanic Girls Enrolled in Advanced High School STEM Courses

Researchers indicate that the United States has fallen behind other nations in science, technology, engineering, and mathematics (STEM) education (President\u27s Council of Advisors on Science and Technology, 2010, 2012). A declining interest in the field of engineering as demonstrated by students who pursue degrees in STEM fields also threatens the U.S. competitive edge (National Science Foundation, 2013; Schneider, Judy, & Mazuca, 2012). Although some students perform successfully in STEM courses, an achievement gap between school-aged boys and girls is well-documented in the literature (e.g., College Board, 2007). Moreover, Hispanic students are underrepresented in science-related courses and careers (Hanley & Noblit, 2009) and even fewer Hispanic girls are attracted to the STEM areas despite the increase in the Hispanic population in general and in higher education (Dolan, 2009). In fact, few studies were located that addressed perspectives of Hispanic girls about their experiences and perceptions related to science and engineering (Crisp, Nora, & Taggart, 2009; Moller et al., 2015; O\u27Shea, Heilbronner, & Reis, 2010). Specifically, there is a need to attract girls and Hispanic students to mathematics and science coursework and careers. Therefore, the purpose of this collective case study was to explore and identify potential barriers and supports related to select Hispanic high school girls\u27 decisions to pursue advanced coursework and future careers in STEM. By increasing awareness of these potential barriers, school leaders will be better positioned to develop strategies and support systems to encourage Hispanic girls to take advanced science courses and seek out postsecondary studies and careers in STEM fields

Phase and precession evolution in the Burgers equation

We present a phenomenological study of the phase dynamics of the one-dimensional stochastically forced Burgers equation, and of the same equation under a Fourier mode reduction on a fractal set. We study the connection between coherent structures in real space and the evolution of triads in Fourier space. Concerning the one-dimensional case, we find that triad phases show alignments and synchronisations that favour energy fluxes towards small scales --a direct cascade. In addition, strongly dissipative real-space structures are associated with entangled correlations amongst the phase precession frequencies and the amplitude evolution of Fourier triads. As a result, triad precession frequencies show a non-Gaussian distribution with multiple peaks and fat tails, and there is a significant correlation between triad precession frequencies and amplitude growth. Links with dynamical systems approach are briefly discussed, such as the role of unstable critical points in state space. On the other hand, by reducing the fractal dimension $D$ of the underlying Fourier set, we observe: i) a tendency toward a more Gaussian statistics, ii) a loss of alignment of triad phases leading to a depletion of the energy flux, and iii) the simultaneous reduction of the correlation between the growth of Fourier mode amplitudes and the precession frequencies of triad phases

Biomass partitioning and gas exchange parameters in different Musa cultivars as influenced by natural shade

Poster presented at Tropentag 2011 Development on the Margin. Bonn (Germany), 3-7 Oct 2011

Force induced stretched state: Effects of temperature

A model of self avoiding walks with suitable constraint has been developed to study the effect of temperature on a single stranded DNA (ssDNA) in the constant force ensemble. Our exact calculations for small chains show that the extension (reaction co-ordinate) may increase or decrease with the temperature depending upon the applied force. The simple model developed here which incorporates semi-microscopic details of base direction provide an explanation of the force induced transitions in ssDNA as observed in experiments.Comment: 5 pages, 8 figures, RevTex

Photosynthesis of three dessert banana cultivars along an altitudinal gradient

Poster presented at Tropentag 2011 - Development on the Margin. Bonn (Germany), 3-7 Oct 2011

Identificación de factores que influyen el rendimiento académico en los alumnos del segundo ciclo de la Escuela de Estomatología de la Universidad Señor de Sipán

Actualmente se conoce que los estudiantes que ingresan al nivel superior universitario revelan una serie de deficiencias académicas que, además de retrasar el proceso de formación en su aprendizaje, constituyen un obstáculo para el desarrollo personal y profesional. La capacidad de aprendizaje de los estudiantes universitarios, está relacionada con una serie de factores extrínsecos e intrínsecos que condicionan la calidad de la asimilación de los conocimientos. Las experiencias del ambiente, tanto como las oportunidades de desarrollo intelectual que se le propicien a los jóvenes, dentro del hogar y la escuela, forma un potencial de recursos básicos para la asimilación de nuevos conocimientos con contenidos más refinados y selectivamente aprendidos; pero también en el aprendizaje intervienen la salud y la dotación natural de inteligencia con que viene determinado cada ser humano. Secada (1972) sostiene que no podemos considerar el rendimiento solamente como resultado de la capacidad intelectual o de las aptitudes, sino también de las condiciones temperamentales y características del individuo

Two-phase stretching of molecular chains

While stretching of most polymer chains leads to rather featureless force-extension diagrams, some, notably DNA, exhibit non-trivial behavior with a distinct plateau region. Here we propose a unified theory that connects force-extension characteristics of the polymer chain with the convexity properties of the extension energy profile of its individual monomer subunits. Namely, if the effective monomer deformation energy as a function of its extension has a non-convex (concave up) region, the stretched polymer chain separates into two phases: the weakly and strongly stretched monomers. Simplified planar and 3D polymer models are used to illustrate the basic principles of the proposed model. Specifically, we show rigorously that when the secondary structure of a polymer is mostly due to weak non-covalent interactions, the stretching is two-phase, and the force-stretching diagram has the characteristic plateau. We then use realistic coarse-grained models to confirm the main findings and make direct connection to the microscopic structure of the monomers. We demostrate in detail how the two-phase scenario is realized in the \alpha-helix, and in DNA double helix. The predicted plateau parameters are consistent with single molecules experiments. Detailed analysis of DNA stretching demonstrates that breaking of Watson-Crick bonds is not necessary for the existence of the plateau, although some of the bonds do break as the double-helix extends at room temperature. The main strengths of the proposed theory are its generality and direct microscopic connection.Comment: 16 pges, 22 figure