Heteroclinic orbits and transport in a perturbed integrable Suris map

Explicit formulae are given for the saddle connection of an integrable family of standard maps studied by Y. Suris. When the map is perturbed this connection is destroyed, and we use a discrete version of Melnikov's method to give an explicit formula for the first order approximation of the area of the lobes of the resultant turnstile. These results are compared with computations of the lobe area.Comment: laTex file with 6 eps figure

Canonical Melnikov theory for diffeomorphisms

We study perturbations of diffeomorphisms that have a saddle connection between a pair of normally hyperbolic invariant manifolds. We develop a first-order deformation calculus for invariant manifolds and show that a generalized Melnikov function or Melnikov displacement can be written in a canonical way. This function is defined to be a section of the normal bundle of the saddle connection. We show how our definition reproduces the classical methods of Poincar\'{e} and Melnikov and specializes to methods previously used for exact symplectic and volume-preserving maps. We use the method to detect the transverse intersection of stable and unstable manifolds and relate this intersection to the set of zeros of the Melnikov displacement.Comment: laTeX, 31 pages, 3 figure

Inclusive Place-Making in Spartanburg, SC: Amplifying Latinx Voices through Community-Based Research

In response to a growing local interest in “place-making” work, our team developed and carried out a research project centered on the ideas of inclusive place, community, and health, with a focus on the inclusion of the growing Latinx community in the Spartanburg area. The project is a first step in what we imagine to be a long arc of community-based research and is in response to the desire of community collaborators for better information to inform their decision-making, particularly with regard to inclusion of Latinx residents. The long-term arc of the research will be shaped by ideas from community partners related to inclusivity; thriving and welcoming community spaces; health equity; and food access and is adaptable to a focus on particular areas or demographics within Spartanburg County. The goal of the present phase of research was to generate qualitative data (1) to inform the implementation of upcoming community projects; (2) to be available to community leaders as a complement to existing quantitative data about areas related to the research focus; (3) to inform the scope, design, and methods of other groups interested in doing related research work, including program evaluation or assessment. Our qualitative approach has sought to respect the “Don’t do anything for us without us” imperative for inclusive community work and aims to create a way to include and amplify the voices of those who will be affected by coming community projects, in informing the implementation of those projects

smarce1 mutants have a defective endocardium and an increased expression of cardiac transcription factors in zebrafish

Animal science

Dominant B-cell epitopes from cancer/stem cell antigen SOC2 recognized by serum samples from cancer patients

Cataloged from PDF version of article.Human sex determining region Y-box 2 (SOX2) is an important transcriptional factor involved in the pluripotency and stemness of human embryonic stem cells. SOX2 plays important roles in maintaining cancer stem cell activities of melanoma and cancers of the brain, prostate, breast, and lung. SOX2 is also a lineage survival oncogene for squamous cell carcinoma of the lung and esophagus. Spontaneous cellular and humoral immune responses against SOX2 present in cancer patients classify it as a tumor-associated antigen (TAA) shared by lung cancer, glioblastoma, and prostate cancer among others. In this study, B-cell epitopes were predicted using computer-assisted algorithms. Synthetic peptides based on the prediction were screened for recognition by serum samples from cancer patients using ELISA. Two dominant B-cell epitopes, SOX2:52-87 and SOX2:98-124 were identified. Prostate cancer, glioblastoma and lung cancer serum samples that recognized the above SOX2 epitopes also recognized the full-length protein based on Western blot. These B-cell epitopes may be used in assessing humoral immune responses against SOX2 in cancer immunotherapy and stem cell-related transplantation

Activity-regulated RNA editing in select neuronal subfields in hippocampus

RNA editing by adensosine deaminases is a widespread mechanism to alter genetic information in metazoa. In addition to modifications in non-coding regions, editing contributes to diversification of protein function, in analogy to alternative splicing. However, although splicing programs respond to external signals, facilitating fine tuning and homeostasis of cellular functions, a similar regulation has not been described for RNA editing. Here, we show that the AMPA receptor R/G editing site is dynamically regulated in the hippocampus in response to activity. These changes are bi-directional, reversible and correlate with levels of the editase Adar2. This regulation is observed in the CA1 hippocampal subfield but not in CA3 and is thus subfield/celltype-specific. Moreover, alternative splicing of the flip/flop cassette downstream of the R/G site is closely linked to the editing state, which is regulated by Ca(2+). Our data show that A-to-I RNA editing has the capacity to tune protein function in response to external stimuli

Correlative analysis of structure and chemistry of LixFePO4 platelets using 4D-STEM and X-ray ptychography

Lithium iron phosphate (LixFePO4), a cathode material used in rechargeable Li-ion batteries, phase separates upon de/lithiation under equilibrium. The interfacial structure and chemistry within these cathode materials affects Li-ion transport, and therefore battery performance. Correlative imaging of LixFePO4 was performed using four-dimensional scanning transmission electron microscopy (4D-STEM), scanning transmission X-ray microscopy (STXM), and X-ray ptychography in order to analyze the local structure and chemistry of the same particle set. Over 50,000 diffraction patterns from 10 particles provided measurements of both structure and chemistry at a nanoscale spatial resolution (16.6-49.5 nm) over wide (several micron) fields-of-view with statistical robustness.LixFePO4 particles at varying stages of delithiation were measured to examine the evolution of structure and chemistry as a function of delithiation. In lithiated and delithiated particles, local variations were observed in the degree of lithiation even while local lattice structures remained comparatively constant, and calculation of linear coefficients of chemical expansion suggest pinning of the lattice structures in these populations. Partially delithiated particles displayed broadly core-shell-like structures, however, with highly variable behavior both locally and per individual particle that exhibited distinctive intermediate regions at the interface between phases, and pockets within the lithiated core that correspond to FePO4 in structure and chemistry.The results provide insight into the LixFePO4 system, subtleties in the scope and applicability of Vegards law (linear lattice parameter-composition behavior) under local versus global measurements, and demonstrate a powerful new combination of experimental and analytical modalities for bridging the crucial gap between local and statistical characterization.Comment: 17 pages, 4 figure

Kernel techniques for adaptive Monte Carlo methods

We introduce a general kernel-informed Monte Carlo algorithm family for fast sampling from Bayesian posterior distributions. Our focus is on the highly challenging Big Models regime, where posteriors often exhibit strong nonlinear correlations and the evaluation of the target density (and its gradient) is either analytically intractable or computationally expensive. To construct efficient sampling schemes in these cases, application of adaptive MCMC methods learning the target geometry becomes critical. We present how kernel methods can be embedded into the adaptive MCMC paradigm enabling to construct rich classes of proposals with attractive convergence and mixing properties. Our ideas are exemplified for three popular sampling techniques: Metropolis-Hastings, Hamiltonian Monte Carlo and Sequential Monte Carlo

Evaluación económica del Programa Moscamed en México (1978-2008)

El objetivo del presente estudio fue evaluar el impacto económico del Programa Moscamed México y del Programa Regional Moscamed, en el país y en el estado de Chiapas. Durante los 31 años del Programa Moscamed (1978-2008), México ha obtenido grandes beneficios entre los que destacan sus crecientes exportaciones de frutas y hortalizas de alto valor a mercados como los de Estados Unidos de América y Japón, que están libres de mosca del Mediterráneo; condición de la que también goza México desde 1982, gracias a la estrategia exitosa de dicho programa.Contiene: 1 Antecedentes del programa Moscamed. 2 Metodología. 3 Estrategia integrada de control de la mosca del Mediterráneo en México. 4 Producción y comercialización de frutas y hortalizas susceptibles de ser atacadas por la mosca del Mediterráneo. 5 Estructura de beneficios. 6 Estructura de costos del programa Moscamed. 7 Análisis económico. 8 Conclusiones y recomendaciones