Conjugate two-dimensional electric potential maps

Two dimensional electric potential maps based on voltage detection in conducting paper are common practice in many physics courses in college. Most frequently, students work on `capacitor-like' geometries with current flowing between two opposite electrodes. A `topographical' investigation across the embedding medium (map of equipotential curves) allows to reassure a number of physical properties. This paper focuses on some less common configurations that bear pedagogical interest. We analyze `open-geometries' with electrodes in the form of long strips with slits. They provide a natural groundwork to bring the student to complex variable methods. Aided by this, we show that shaping the conducting paper board one may analyze finite size effects, as well as some meaningful discontinuities in the measured potential. The concept of conjugate electric potentials is exploited. Equipotentials and electric field lines acquire interchangeable roles and may be obtained in complementary `dual' experiments. A feasible theoretical analysis based on introductory complex variables and standardized numerics gives a remarkable quantification of the experimental results.Comment: 15 pages, 8 figure

Economic consequences of low fertility in Europe

This paper focuses on possible economic consequences of low fertility in Europe. It summarizes a selection of papers that were presented at a conference at the University of St. Gallen in April 2008. This introduction also reviews the history of falling fertility in Europe and the literature that explores its causes, its potential implications, and possible policy responses. It summarizes the evolution of thinking about the relationship between population growth and economic development, with attention to recent work on the mechanisms through which fertility decline can spur economic growth if the necessary supporting conditions are met. The paper also identifies some of the challenges of population aging that are associated with low fertility and suggests that there may be less reason for alarm than has been suggested by some observers. --

Economic Consequences of Low Fertility in Europe

This special issue of the European Journal of Population focuses on possible economic consequences of low fertility in Europe. This introduction reviews the history of falling fertility in Europe and the literature that explores its causes, its potential implications, and possible policy responses. It also summarizes the evolution of thinking about the relationship between population growth and economic development, with attention to recent work on the mechanisms through which fertility decline can spur economic growth if the necessary supporting conditions are met. The introduction also identifies some of the challenges of population aging that are associated with low fertility and suggests that there may be less reason for alarm than has been suggested by some observers. The papers that appear in this special issue are also summarized.Economic consequences, low fertility, Europe

A technique for automatic real time scoring of several simultaneous sleep electroencephalograms

Automatic real-time scoring of simultaneous sleep electroencephalogram

Economic consequences of low fertility in Europe

This paper focuses on possible economic consequences of low fertility in Europe. It summarizes a selection of papers that were presented at a conference at the University of St. Gallen in April 2008. This introduction also reviews the history of falling fertility in Europe and the literature that explores its causes, its potential implications, and possible policy responses. It summarizes the evolution of thinking about the relationship between population growth and economic development, with attention to recent work on the mechanisms through which fertility decline can spur economic growth if the necessary supporting conditions are met. The paper also identifies some of the challenges of population aging that are associated with low fertility and suggests that there may be less reason for alarm than has been suggested by some observers

Critical Translingual Perspectives on California Multilingual Education Policy

Policies restricting bilingual education have yielded to policy frameworks touting its benefits. This shift corresponds with evolving lines of debate, focusing now on how bilingual education can best support racialized bilingual learners. One element of this new debate is the perspective on language underlying curriculum in bilingual programs, with a focus on translanguaging– normalization of the language practices of bilingual communities and positing that bilinguals draw from a singular linguistic repertoire. This article examines initiatives undertaken in California between 2010 and 2019 using Critical Policy Analysis. The work highlights that while opportunities for translanguaging have arisen, tensions between heteroglossic perspectives and the impulses toward standardization and commodification of language undermine such possibilities, and that notable gaps remain between teacher preparation frameworks and intended pedagogical practice

Nanosized superconducting constrictions

Nanowires of lead between macroscopic electrodes are produced by means of an STM. Magnetic fields may destroy the superconductivity in the electrodes, while the wire remains in the superconducting state. The properties of the resulting microscopic Josephson junctions are investigated.Comment: 3 pages,3 eps figures include

Width variations in river meandering evolution and chute cutoff process

Many models have been proposed to simulate and understand the long-term evolution of meandering rivers. Nevertheless, some modeling problem still needs to be solved, e.g., the stability of long-term simulations when width variations are accounted for. The present thesis proposes a physics-statistical based approach to simulate the river bank evolution, such that erosion and deposition processes act independently, with a specific shear stress threshold for each of them. In addition, the width evolution is linked with a river-specific parametric probability distribution. The analysis of a representative sample of meandering configurations, extracted from Lidar images, indicate that Generalized Extreme Values (GEV) probability density function nicely describe the along channel cross-section width distribution. For a given river, the parameters of the distribution keep almost constant in time, with significant variations observed only as after cutoff events that significantly sharpen the length of the river. The constraint of the river width based on the assumption of a GEV probability distribution ensures as the river moves throughout the floodplain adapting its width, the stability of long-term simulations. The application of the model to a reach of the Ucayali river appears to satisfactorily reproduce the planform evolution of the river and yields realistic values of the cross-section widths. The second topic considered in the thesis is the formation of chute cutoffs, which produce substantial and non-local changes in the river planform, thereby affecting the morphological evolution. The occurrence of this type of cutoffs is one of the less predictable events in the evolution of rivers, as a multiplicity of control factors are involved in their formation and maintenance. Significant contributions have appeared in the literature in the recent years, which shed light on the complex mechanisms that first lead to the incision of chutes through the floodplain, and that eventually determines the fate of both the cutoff bend and the new channel. However, the subject is not yet settled, and a systematic physic-based framework is still missing. In this thesis, two different forcing factors leading to chute cutoffs are highlighted, the channelized flow inertia and the topographic and sedimentary heterogeneity of the floodplain. Using two hydrodynamic models, the general features of the processes leading to chute cutoffs are investigated by assessing a few representative case studies

Making Movidas: Cultivating Leadership Through Conocimiento In An Undergraduate Student Retreat

This educational case study examines the efforts of one Hispanic-Serving Institution (HSI) to counter deficit narratives and provide institutional as well as interpersonal supports for Latinx student success through a Student Leadership Retreat. We consider these activities and students’ experiences therein through the lenses of Latinx leadership and Gloria Anzaldúa’s notion of conocimiento. To do so, we rely on established methods in Chicanx Studies that center the voices of participants and communities to foreground emic systems of knowledge and activity qualitatively. Specifically, we examined students’ experiences in programming undergirded by conocimiento (iterative and dialogic understanding of ourselves and others), cariño (care for self and others), and confianza (trust) in contrast to more traditionally individualistic, competitive, and transactional arrangements within higher education