Inter- and Intramolecular recombinations in the Cucumber Mosaic Virus genome related to adaptation to Alstroemeria

In four distinct alstroemeria-infecting cucumber mosaic virus (CMV) isolates, additional sequences of various lengths were present in the 3' nontranslated regions of their RNAs 2 and 3, apparently the result of intra- and intermolecular recombination events. Competition experiments revealed that these recombined RNA 2 and 3 segments increased the biological fitness of CMV in alstroemeri

Ultraviolet (UV) B effects on growth and yield of three contrasting sweet potato cultivars

Ground-level UV-B will stay at a high level in the next several decades and influence sweet potato growth and yield because of the remaining chlorofluorocarbons in the atmosphere. The study explored three UV-B (none, ambient, and elevated/projected) levels on three contrasting sweet potato cultivars (Beauregard, Hatteras, and Louisiana 1188) using sunlit plant growth chambers at Mississippi State University. The results showed that UV-B influenced three cultivars differently. Growth, photosynthetic rate, epidermal and leaf structure of Beauregard were negatively influenced under ambient and elevated UV-B. On the contrary, Hatteras was positively influenced, and Louisiana 1188 was influenced by elevated UV-B positively on leaf thickness and waxes content, but negatively on the vine length, dry mass, and leaf area. In summary, Beauregard, Louisiana 1188, and Hatteras were UV-B sensitive, moderately sensitive, and tolerant, respectively. Developing UV-B tolerant cultivars will benefit under both current and projected UV-B exposures

Dynamic Modelling and Genetic- Based Motion Planning of Mobile Manipulator Systems with Nonholonomic Constraints

An approach for modelling and motion planning of a mobile manipulator system with nonholonomic constraint is presented in this paper. The Newton-Euler equations are used to obtain the complete dynamics of the system. Given the trajectory of the end-effector of the manipulator, near-optimal trajectories for mobile platform and manipulator joints are obtained by using an efficient genetic algorithm with torque and manipulability optimisation and obstacle avoidance. An obstacle avoidance scheme is presented by applying geometric analysis. Various simulations of a platform with a 3-link onboard manipulator are presented to show the effectiveness of the presented methods

TENTATIVE DESIGN GUIDE FOR CALCULATING THE VIBRATION RESPONSE OF FLEXIBLE CYLINDRICAL ELEMENTS IN AXIAL FLOW.

Many reactor and plant equipment components, such as fuel pins, control rods, and heat exchanger tubes, are long, slender, beam-like members which are exposed to nominally axial coolant flow. The flowing coolant represents a source of energy which can induce vibratory motion of these components. This design guide presents a relationship for calculating the root-mean-square (rms) displacement of a flexible rod or tube in axial flow. The relationship is based on the results of a parameter study and is valid for components that can be approximated as beams with either simply-supported or fixed-fixed ends. It is given in terms of beam natural frequency, damping factor, and intensity of the mean-square spectral density of the pressure field in the low-frequency range; all three are functions of mean axial flow velocity. Empirical expressions are developed for damping factor and intensity of the mean-square pressure spectrum. With these, an empirical equation for rms displacement is written which is in terms of known quantities and, therefore, provides a tool which can be used by designers. Since the equation is based on experiments involving a smooth rod in flow with minimal entrance effects, the predicted displacements should be interpreted and used with care. They are not conservative and, at best, will represent the minimum response to be expected. (auth

Fermionic superfluidity: From high Tc superconductors to ultracold Fermi gases

We present a pairing fluctuation theory which self-consistently incorporates finite momentum pair excitations in the context of BCS--Bose-Einstein condensation (BEC) crossover, and we apply this theory to high $T_c$ superconductors and ultracold Fermi gases. There are strong similarities between Fermi gases in the unitary regime and high Tc superconductors. Here we address key issues of common interest, especially the pseudogap. In the Fermi gases we summarize recent experiments including various phase diagrams (with and without population imbalance), as well as evidence for a pseudogap in thermodynamic and other experiments.Comment: Expanded version, invited talk at the 5th International Conference on Complex Matter -- Stripes 2006, 6 pages, 6 figure

Onsager Relations and Hydrodynamic Balance Equations in 2D Quantum Wells

In this letter we clarify the role of heat flux in the hydrodynamic balance equations in 2D quantum wells, facilitating the formulation of an Onsager relation within the framework of this theory. We find that the Onsager relation is satisfied within the framework of the 2D hydrodynamic balance equation transport theory at sufficiently high density. The condition of high density is consonant with the requirement of strong electron-electron interactions for the validity of our balance equation formulation.Comment: 11 pages, RevTex, 4 postscript figures are avaliable upon reques

A bayesian perspective on intervention research: Using prior information in the development of social and health programs

Objective: By presenting a simulation study that compares Bayesian and classical frequentist approaches to research design, this paper describes and demonstrates a Bayesian perspective on intervention research. Method: Using hypothetical pilot-study data where an effect size of 0.2 had been observed, we designed a 2-arm trial intended to compare an intervention with a control condition (e.g., usual services). We determined the trial sample size by a power analysis with a Type I error probability of 2.5% (1-sided) at 80% power. Following a Monte-Carlo computational algorithm, we simulated 1 million outcomes for this study and then compared the performance of the Bayesian perspective with the performance of the frequentist analytic perspective. Treatment effectiveness was assessed using a frequentist t-test and an empirical Bayesian t-test. Statistical power was calculated as the criterion for comparison of the 2 approaches to analysis. Results: In the simulations, the classical frequentist t-test yielded 80% power as designed. However, the Bayesian approach yielded 92% power. Conclusion: Holding sample size constant, a Bayesian analytic approach can improve power in intervention research. A Bayesian approach may also permit smaller samples holding power constant. Using a Bayesian analytic perspective could reduce design demands in the developmental experimentation that typifies intervention research

A bayesian approach to sample size estimation and the decision to continue program development in intervention research

Objective: In intervention research, the decision to continue developing a new program or treatment is dependent on both the change-inducing potential of a new strategy (i.e., its effect size) and the methods used to measure change, including the size of samples. This article describes a Bayesian approach to determining sample sizes in the sequential development of interventions. Description: Because sample sizes are related to the likelihood of detecting program effects, large samples are preferred. But in the design and development process that characterizes intervention research, smaller scale studies are usually required to justify more costly, larger scale studies. We present 4 scenarios designed to address common but complex questions regarding sample-size determination and the risk of observing misleading (e.g., false-positive) findings. From a Bayesian perspective, this article describes the use of decision rules composed of different target probabilities and prespecified effect sizes. Monte-Carlo simulations are used to demonstrate a Bayesian approach—which tends to require smaller samples than the classical frequentist approach—in the development of interventions from one study to the next

Learner conceptions of biological processes in a content and language integrated learning context

In science education, learner conceptions concern how students interpret and understand scientific issues. Recent research into learner conceptions acknowledges students’ knowledge, experiences, language, and resources that demonstrate scientific reasoning rather than their misunderstanding. In this study, we follow a functional approach to learner conceptions and explore the functions of language in constructing and representing students’ interpretations of scientific knowledge. The major theoretical framework guiding this research is the thematic pattern analysis theory (Lemke, 1990), which views scientific phenomena as the patterning of semantic relations (i.e., the relation between scientific concepts and its function). We aim to examine the emergence of learner conceptions and potential factors informing student thematic patterning of scientific issues. This study (research ethics reference number: 20200122) is situated in an undergraduate biology course that employed Content Language Integrated Learning (CLIL) in which equal emphasis was given on learning biological concepts and learning the languaging (i.e., appropriately using the thematic patterns) of the concepts. We focus on one written assignment in which students were asked to reason about the mechanism of Antidiuretic Hormone (ADH) in water transport in the scenario of water intoxification from extensive exercise and water consumption. The primary data included students’ written responses, question prompts, and marking schemes. Other textual data including textbooks, PowerPoint slides, and teacher notes were consulted to have a contextualized understanding of students’ responses. Preliminary analysis revealed a basic thematic pattern embedded in most students’ responses: EXERCISE (condition) --\u3e SWEATING (result/condition) --\u3e WATER LOSS (result/condition) --\u3e WATER CONSUMPTION (result/condition). We also identified different thematic patterns of student conceptions along each aspect of the basic pattern. To explore factors informing learner conceptions, we then compared the thematic patterns of students’ responses and the model answer, which helped demonstrate how implicit and conflicting thematic patterns incorporated in instructional materials may hamper students’ understanding of scientific concepts. For example, the notion of water may contain an implicit semantic relation of hyponym, i.e., water (subordinate term) as a specific type of molecule (superordinate category) composed of atoms; however, students may draw from their everyday experience and view water as a free-flowing substance. This study thus calls for biology teachers’ attention to the patterning of scientific representations. It also provides implications for science education in general and stimulates science teachers’ thinking in their language use in teaching scientific concepts. Works cited Lemke, J. (1990). Talking science: Language, learning, and values. Ablex Publishing Corporation. Tang, K. S. (2020). Discourse strategies for science teaching and learning: Research and practice. Routledge

Dynamics of quantum quenching for BCS-BEC systems in the shallow BEC regime

The problem of coupled Fermi-Bose mixtures of an ultracold gas near a narrow Feshbach resonance is approached through the time-dependent and complex Ginzburg-Landau (TDGL) theory. The dynamical system is constructed using Ginzburg-Landau-Abrikosov-Gor'kov (GLAG) path integral methods with the single mode approximation for the composite Bosons, and the equilibrium states are obtained in the BEC regime for adiabatic variations of the Feshbach detuning along the stationary solutions of the dynamical system. Investigations into the rich superfluid dynamics of this system in the shallow BEC regime yields the onset of multiple interference patterns in the dynamics as the system is quenched from the deep-BEC regime. This results in a partial collapse and revival of the coherent matter wave field of the BEC, whose temporal profile is reported.Comment: 24 pages, 7 figures. Submitted to European Journal of Physics Plu