New Insights into the Degradation Path of Deltamethrin

Pyrethroids are among the insecticidal compounds indicated by the World Health Organization for mitigation of vector-borne diseases. Active deltamethrin (with chiral configuration α-S,1-R-cis) is one of the most effective pyrethroids characterized by low toxicity to humans, and it is currently tested as active ingredient for insecticidal paints. Nevertheless, several degradation processes can occur and affect the insecticidal efficacy in the complex paint matrix. In the present study, a detailed NMR analysis of deltamethrin stability has been carried out under stress conditions, mimicking a water-based insecticidal paint environment. Two novel by-products, having a diastereomeric relationship, were identified and their structure was elucidated by combining NMR, HPLC, GC-MS, and ESI-MS analyses. These compounds are the result from a nucleophilic addition involving deltamethrin and one of its major degradation products, 3-phenoxybenzaldehyde. Given the known toxicity of the aldehyde, this reaction could represent a way to reduce its concentration into the matrix. On the other hand, the toxicology of these compounds towards humans should be addressed, as their presence may adversely affect the performance of deltamethrin-containing products.     

An approach to real-time magnetic resonance imaging for speech production

Magnetic resonance imaging (MRI) has served as a valuable tool for studying static postures in speech production. Now, recent improvements in temporal resolution are making it possible to examine the dynamics of vocal-tract shaping during fluent speech using MRI. The present study uses spiral k-space acquisitions with a low flip-angle gradient echo pulse sequence on a conventional GE Signa 1.5-T CV/i scanner. This strategy allows for acquisition rates of 8-9 images per second and reconstruction rates of 20-24 images per second, making veridical movies of speech production now possible. Segmental durations, positions, and interarticulator timing can all be quantitatively evaluated. Data show clear real-time movements of the lips, tongue, and velum. Sample movies and data analysis strategies are presented.     

On the embeddability of certain infinitely divisible probability measures on Lie groups

We describe certain sufficient conditions for an infinitely divisible probability measure on a Lie group to be embeddable in a continuous one-parameter semigroup of probability measures. A major class of Lie groups involved in the analysis consists of central extensions of almost algebraic groups by compactly generated abelian groups without vector part. This enables us in particular to conclude the embeddability of all infinitely divisible probability measures on certain connected Lie groups, including the so called Walnut group. The embeddability is concluded also under certain other conditions. Our methods are based on a detailed study of actions of certain nilpotent groups on special spaces of probability measures and on Fourier analysis along the fibering of the extension.     

Innovations in statistical modeling to connect data,chance and context

Statistical modeling is emerging as a fertile research environment in which to promote and learn about student statistical reasoning processes. We outline a paradigm shift toward a modeling perspective that is occurring in statistics education research and how statistical modeling processes involve connecting data, chance and context. The innovative task and software designs and theoretical frameworks that are under development for explicating student reasoning and pedagogy are discussed. In conclusion, we reflect on statistics education research.     

Functional data analysis of prosodic effects on articulatory timing

An application of functional data analysis (FDA) (Ramsay and Silverman, 2005, Functional Data Analysis, 2nd ed. (Springer-Verlag, New York)) for linguistic experimentation is explored. The functional time-registration method provided by FDA is shown to offer novel advantages in the investigation of articulatory timing. Traditionally, articulatory studies examining the effects of linguistic variables such as prosody on articulatory timing have relied on comparing the durations of speech intervals of interest defined by kinematic landmarks. Such measurements, however, do not preserve information on the detailed, continuous pattern of articulatory timing that unfolds during these intervals. We present an approach that allows the analysis of entire, continuous kinematic trajectories obtained in a movement tracking experiment examining the influence of a phrasal boundary on articulatory patterning. FDA time deformation functions, after alignment of test and reference (control) signals, reveal delaying of articulator movement (i.e., slowing of the internal clock rate) in the presence of a phrase boundary as the speech stream recedes from the boundary. This is a theoretically predicted pattern (Byrd and Saltzman, 2003, The elastic phrase: Modeling the dynamics of boundary-adjacent lengthening, Journal of Phonetics 31, 149-180.), which would be more difficult to validate with a traditional interval-based approach. It is concluded that the FDA time alignment method provides a useful tool for characterizing timing patterns in linguistic experimentation based on continuous kinematic trajectories.     

Variable orbital coupling in a two-dimensional quantum-dot solid probed on a local scale

The optoelectronic properties of semiconductor quantum-dot (QD) solids depend on the electronic structure of the building blocks and their interactions. Disorder may affect the coupling on a local scale. We have measured the density of states of 2D arrays of PbSe QDs site by site using scanning tunneling spectroscopy. It markedly differs from that of isolated QDs due to electronic coupling in the array. We observe strong local variations in the coupling strength with two prototypical cases: delocalization of the conduction electrons only, and full coupling with both hole and electron delocalization over the QD sites in the array.     

An Ergodic Decomposition Defined by Regular Jointly Measurable Markov Semigroups on Polish Spaces

For a regular jointly measurable Markov semigroup on the space of finite Borel measures on a Polish space we give a Yosida-type decomposition of the state space, which yields a parametrisation of the ergodic probability measures associated to this semigroup in terms of subsets of the state space. In this way we extend results by Costa and Dufour (J. Appl. Probab. 43:767?C781, 2006). As a consequence we obtain an integral decomposition of every invariant probability measure in terms of the ergodic probability measures. Our approach is completely centered around the reduction to and relationship with the case of a single regular Markov operator associated to the Markov semigroup, the resolvent operator, which enables us to fully exploit results in that situation (Worm and Hille in Ergod. Theory Dyn. Syst. 31(2):571?C597, 2011).     

On generalizations of the KMS-boundary condition

We investigate the possibility to generalize the KMS-boundary condition for a thermodynamical system by following essentially the same procedure that for a finite system would amount to choosing a certain class of more general density functions on phase space (or density matrices) than the ones corresponding to the canonical or grand-canonical ensemble.