The effects of historic earthen barriers on northern New England tital marshes

Berms, defined as historic earthen barriers, represent one type of hydrological modification introduced by humans in the tidal marshes of northern New England. Three different research approaches were applied to study the impact of berms on various tidal marsh dynamics. The descriptive study shows that restricted flooding from berm interference can result in significantly altered physical gradients in addition to landward subsidence and pool development. The results from the transplant experiment indicate that the altered landward structure affects the relative importance of biological interactions, namely herbivory, in controlling plant species distribution. The predictive GIS analyses illustrate the location of 34 berm sites within the Great Bay Estuary and highlight the bermed marshes most at risk of invasion by the non-native variety of Phragmites australis and submergence during sea level rise. Based on the combined findings, berms have the potential to reduce the overall biodiversity and integrity of tidal marshes

Energy dependence of the quark masses and mixings

The one loop Renormalization Group Equations for the Yukawa couplings of quarks are solved. From the solution we find the explicit energy dependence on $t=\ln E/\mu$ of the evolution of the {\em down} quark masses $q=d,s,b$ from the grand unification scale down to the top quark mass $m_{t}$. These results together with the earlier published evolution of the {\em up} quark masses completes the pattern of the evolution of the quark masses. We also find the energy dependence of the absolute values of the Cabibbo-Kobayashi-Maskawa (CKM) matrix $|V_{ij}|$. The interesting property of the evolution of the CKM matrix and the ratios of the quark masses: $m_{u,c}/m_{t}$ and $m_{d,s}/m_{b}$ is that they all depend on $t$ through only one function of energy $h(t)$.Comment: Talk presented at the IX Mexican School on Particles and Fields, August 9-19, Metepec, Pue., Mexico. To be published in the AIP Conference Proceedings. 5 pages and 1 eps figure included in the tex

Discrete model for laser driven etching and microstructuring of metallic surfaces

We present a unidimensional discrete solid-on-solid model evolving in time using a kinetic Monte Carlo method to simulate micro-structuring of kerfs on metallic surfaces by means of laser-induced jet-chemical etching. The precise control of the passivation layer achieved by this technique is responsible for the high resolution of the structures. However, within a certain range of experimental parameters, the microstructuring of kerfs on stainless steel surfaces with a solution of $\mathrm{H}_3\mathrm{PO}_4$ shows periodic ripples, which are considered to originate from an intrinsic dynamics. The model mimics a few of the various physical and chemical processes involved and within certain parameter ranges reproduces some morphological aspects of the structures, in particular ripple regimes. We analyze the range of values of laser beam power for the appearance of ripples in both experimental and simulated kerfs. The discrete model is an extension of one that has been used previously in the context of ion sputtering and is related to a noisy version of the Kuramoto-Sivashinsky equation used extensively in the field of pattern formation.Comment: Revised version. Etching probability distribution and new simulations adde

A Video Tour through ViSta 6.4

This paper offers a visual tour throughout ViSta 6.4, a freeware statistical program based on Lisp-Stat and focused on techniques for statistical visualization (Young 2004). This travel around ViSta is based on screen recordings that illustrate the main features of the program in action. The following aspects of ViSta 6.4 are displayed: the program's interface (ViSta's desktop, menubar and pop-up menus, help system); its data management capabilities (data input and editing, data transformations); features associated to data analysis (data description, statistical modeling); and the options for Lisp-Stat development in ViSta. The video recordings associated to this tour (.wmv files) can be visualized at http://www.jstatsoft.org/v13/i08/ using the Internet Explorer navigator, or by clicking on the figures in the paper.

Universal resources for approximate and stochastic measurement-based quantum computation

We investigate which quantum states can serve as universal resources for approximate and stochastic measurement-based quantum computation, in the sense that any quantum state can be generated from a given resource by means of single-qubit (local) operations assisted by classical communication. More precisely, we consider the approximate and stochastic generation of states, resulting e.g. from a restriction to finite measurement settings or from possible imperfections in the resources or local operations. We show that entanglement-based criteria for universality obtained for the exact, deterministic case can be lifted to the much more general approximate, stochastic case, moving from the idealized situation considered in previous works, to the practically relevant context of non-perfect state preparation. We find that any entanglement measure fulfilling some basic requirements needs to reach its maximum value on some element of an approximate, stochastic universal family of resource states, as the resource size grows. This allows us to rule out various families of states as being approximate, stochastic universal. We provide examples of resources that are efficient approximate universal, but not exact deterministic universal. We also study the robustness of universal resources for measurement-based quantum computation under realistic assumptions about the (imperfect) generation and manipulation of entangled states, giving an explicit expression for the impact that errors made in the preparation of the resource have on the possibility to use it for universal approximate and stochastic state preparation. Finally, we discuss the relation between our entanglement-based criteria and recent results regarding the uselessness of states with a high degree of geometric entanglement as universal resources.Comment: 17 pages; abstract shortened with respect to the published version to respect the arXiv limit of 1,920 character

Intrinsic limitations of inverse inference in the pairwise Ising spin glass

We analyze the limits inherent to the inverse reconstruction of a pairwise Ising spin glass based on susceptibility propagation. We establish the conditions under which the susceptibility propagation algorithm is able to reconstruct the characteristics of the network given first- and second-order local observables, evaluate eventual errors due to various types of noise in the originally observed data, and discuss the scaling of the problem with the number of degrees of freedom

Computing and Visualizing Log-linear analysis interactively

The purpose of this paper is to describe a simple program for computing log-linear analysis based on a direct manipulation interface that emphasizes the use of plots for guiding the analysis and evaluating the results obtained. The program described here works as a plugin for ViSta (Young 1997) and receives the name of LoginViSta (for Log-linear analysis in ViSTa). ViSta is a statistical package based on Lisp-Stat. Lisp-Stat is a statistical programming environment developed by Luke Tierney (1990) that features an object-oriented approach for statistical computing and one that allows for The purpose of this paper is to describe a simple program for computing log-linear analysis based on a direct manipulation interface that emphasizes the use of plots for guiding the analysis and evaluating the results obtained. The program described here works as a plugin for ViSta (Young 1997) and receives the name of LoginViSta (for Log-linear analysis in ViSTa). ViSta is a statistical package based on Lisp-Stat. Lisp-Stat is a statistical programming environment developed by Luke Tierney (1990) that features an object-oriented approach for statistical computing and one that allows for Computing and Visualizing Pedro Valero-Mora and Forrest W. Young interactive and dynamic graphs

From stem and progenitor cells to neurons in the developing neocortex: Key differences among hominids

Comparing the biology of humans to that of other primates, and notably other hominids, is a useful path to learn more about what makes us human. Some of the most interesting differences among hominids are closely related to brain development and function, for example behaviour and cognition. This makes it particularly interesting to compare the hominid neural cells of the neocortex, a part of the brain that plays central roles in those processes. However, well-preserved tissue from great apes is usually extremely difficult to obtain. A variety of new alternative tools, for example brain organoids, are now beginning to make it possible to search for such differences and analyse their potential biological and biomedical meaning. Here, we present an overview of recent findings from comparisons of the neural stem and progenitor cells (NSPCs) and neurons of hominids. In addition to differences in proliferation and differentiation of NSPCs, and maturation of neurons, we highlight that the regulation of the timing of these processes is emerging as a general foundational difference in the development of the neocortex of hominids

Conocimiento didáctico del contenido curricular del profesorado de Química

Esta comunicación presenta los resultados finales del proyecto El conocimiento didáctico del contenido curricular, CDCC: una estrategia sustentada en el diseño de tramas conceptuales, financiado por el Centro de investigaciones de la UPN, (CIUP: DQU-025-07). Las preguntas centrales fueron: ¿cuáles son los referentes teórico/prácticos que definen el CDCC, de qué manera el CDCC le permite al profesorado de química diseñar Tramas Histórico Epistemológicas (THE) y tramas didácticas (TD), qué aspectos tienen en cuenta al seleccionar, diseñan e implementan los contenidos de enseñanza en química? El trabajo se realizó con profesores de química en formación inicial (PFI) de educación media en Bogotá, durante el 2007 y 2008, que hacían su práctica pedagógica/didáctica y profesores en ejercicio, PE que tienen varios años de experiencia docente