High resolution imaging with Fresnel interferometric arrays: suitability for exoplanet detection

We propose a new kind of interferometric array that yields images of high dynamic range and large field. The numerous individual apertures in this array form a pattern related to a Fresnel zone plate. This array can be used for astrophysical imaging over a broad spectral bandwidth spanning from the U.V. (50 nanometers) to the I.R. (20 microns). Due to the long focal lengths involved, this instrument requires formation-flying of two space borne vessels. We present the concept and study the S/N ratio in different situations, then apply these results to probe the suitability of this concept to detect exoplanets.Comment: 12 pages, 19 figures, to be published in A&

International Remittances and Income Inequality: An Empirical Investigation

The aim of this paper is to provide comprehensive empirical evidence on the relationship between international remittances and income inequality. In simple cross-country regressions we find a non-monotonic link between these two variables when using ordinary least squares, instrumental variables; we also test our hypothesis using dynamic panel data methods. We provide evidence in support of existing theoretical work that accounts for network effects that describe how, in the first stages of migration history, there is an inequality-increasing effect of remittances on income inequality. Then, as the opportunity cost of migrating is lowered due to these effects, remittances sent to those households have a negative impact on inequality. We also show how education and the development of the financial sector can help countries to reach the inequality-decreasing section of the curve more quickly. Our results are robust to several empirical specifications, as well as for a wide variety of inequality measures.

Fresnel Interferometric Imager: ground-based prototype

The Fresnel Interferometric Imager is a space-based astronomical telescope project yielding milli-arc second angular resolution and high contrast images with loose manufacturing constraints. This optical concept involves diffractive focusing and formation flying: a first "primary optics" space module holds a large binary Fresnel Array, and a second "focal module" holds optical elements and focal instruments that allow for chromatic dispersion correction. We have designed a reduced-size Fresnel Interferometric Imager prototype and made optical tests in our lab, in order to validate the concept for future space missions. The Primary module of this prototype consists of a square, 8 cm side, 23 m focal length Fresnel array. The focal module is composed of a diaphragmed small telescope used as "field lens", a small cophased diverging Fresnel Zone Lens (FZL) that cancels the dispersion and a detector. An additional module collimates the artificial targets of various shapes, sizes and dynamic ranges to be imaged. In this paper, we describe the experimental setup, different designs of the primary Fresnel array, and the cophased Fresnel Zone Lens that achieves rigorous chromatic correction. We give quantitative measurements of the diffraction limited performances and dynamic range on double sources. The tests have been performed in the visible domain, lambda = 400 - 700 nm. In addition, we present computer simulations of the prototype optics based on Fresnel propagation, that corroborate the optical tests. This numerical tool has been used to simulate the large aperture Fresnel arrays that could be sent to space with diameters of 3 to 30 m, foreseen to operate from Lyman-alpha (121 nm) to mid I.R. (25 microns).Comment: 10 pages, 13 figures; accepted for publication in Applied Optic

Does Educational Intervention Reduce the Number of Food Violations.

The objective of this study was to examine the educational intervention that restaurant employees received to see if it reduced the number of food violations in Orange County, California, U.S.. The class, which began in 2007, is known as the Food Employee Education and Sanitation Training (FEEST). This study revealed that the post-test results from FEEST demonstrated a significant improvement in food safety knowledge, and almost all of the participants showed a significant improvement in food safety knowledge. A comparison of inspection reports immediately before and after participation in FEEST showed that food establishments greatly reduced the number of major violations, but the reduction in minor violations was minimal. Further results showed that overall, post-class inspections were not helpful in reducing the number of violations. Moreover, results showed that out of the participating restaurants, those that received a fee and formal letter requiring correction of the violations, known as a Notice of Violation (NOV) or Notice of Decision (NOD), do well on inspection reports in reducing major violations than those who did not receive one, but both types of restaurants were not able to significantly reduce the number of minor violations. These results might be associated with the knowledge and commitment of the restaurant employees. Restaurant employees are not using the food safety knowledge they gained during the educational intervention. Therefore, further training is required to educate restaurant employees, and more should be done to encourage the practice of safe food handling and sanitation

Curvature sensor for the measurement of the static corneal topography and the dynamic tear film topography in the human eye

A system to measure the topography of the first optical surface of the human eye noninvasively by using a curvature sensor is described. The static corneal topography and the dynamic topography of the tear film can both be measured, and the topographies obtained are presented. The system makes possible the study of the dynamic aberrations introduced by the tear film to determine their contribution to the overall ocular aberrations in healthy eyes, eyes with corneal pathologies, and eyes wearing contact lenses

A multimodal approach to investigating the importance of emotional functioning in childhood and adolescence

Emotional functioning is a key component of both healthy and abnormal development in children and adolescents. It entails the experience, expression and regulation of emotions as well as emotional disorders. Although both the experience and the regulation of emotions change across the lifespan, they do so at an especially intense and rapid rate throughout childhood and adolescence. It is therefore crucial to investigate the role of different aspects of emotional functioning in various domains in these populations. Moreover, the onset of most emotional disorders occurs in adolescence, and prevalence rates of anxiety and depressive disorders are especially high during this period of life. For the purpose of this thesis, three components of emotional functioning were studied, using various methods across several domains. The first aim was to examine the role of emotion regulation in chronic pain (Koechlin, Coakley, Schechter, Werner, & Kossowsky, 2018, Study I). For this purpose, a systematic literature search was conducted and studies meeting specific criteria were then synthesized to investigate whether emotion regulation might enhance existing frameworks of chronic pain. In addition, associations between two broad categories of emotion regulation (namely antecedent- and response-focused emotion regulation) and chronic pain were explored. Emotion regulation depends to a great extent on emotional reactivity, i.e. the individual threshold required for emotional reactions – experiencing more and more intense emotions can complicate adequate emotion regulation. Hence, the second aim of this study was to analyze how emotional reactivity influences the occurrence of adjustment problems in adolescents who experience stressful life events in their childhood years (Koechlin, Donado, Berde, & Kossowsky, 2018, Study II). In order to achieve this second aim, a large longitudinal dataset was used and several covariates, among them emotional reactivity, were analyzed with the aim of predicting adjustment problems in 956 children who had experienced some or many stressful life events. Finally, as the prevalence rates of emotional disorders are high in adolescence, the third aim was to examine the efficacy and safety of a common intervention, namely two classes of antidepressants, selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). In order to address this aim, a meta-analytic approach was chosen, and all randomized, double-blind, placebo-controlled trials of SSRIs and SNRIs in children and adolescents younger than 18 years who had been diagnosed with an emotional disorder were included (Locher, Koechlin et al., 2017). Study I showed that in the included reports, emotion regulation was rarely directly associated with pain intensity or pain-related disability. Rather, the relationship between both groups of emotion regulation strategies (antecedent- and response-focused) and chronic pain seemed to be mediated by psychological factors such as high emotionality, anxiety, or negative mood. This raises questions for future research, such as whether interventions that target emotion regulation specifically have the potential to relieve symptoms of chronic pain and emotional disorders simultaneously. Study II found that adjustment problems were best predicted by high emotional reactivity and many stressful life events. The results of this study point to the potential that emotional reactivity holds for the prevention and treatment of adjustment problems in adolescence. Study III revealed that even though antidepressants were more effective than a placebo in treating common emotional disorders in children and adolescents, these effects were small and disorder-specific. The results of this analysis present multiple avenues for further research, such as the underlying differences and similarities in emotional disorders that might help explain the difference in response to antidepressants and placebo. Patterns of emotional functioning develop in childhood, but may persist into adulthood, which highlights the importance of adaptive emotional functioning. This thesis sheds light on how emotional functioning influences chronic pain and the occurrence of adjustment problems in the face of stressful life events, and examines a common treatment for emotional disorders. Future research should focus on age-specific changes in emotional functioning and how these influence chronic pain, emotional disorders and other domains. This approach would allow researchers to tailor interventions and prevention to age-specific needs and abilities

New Analytic Techniques for Proving the Inherent Ambiguity of Context-Free Languages

International audienceThis article extends the work of Flajolet [Philippe Flajolet, 1987] on the relation between generating series and inherent ambiguity. We first propose an analytic criterion to prove the infinite inherent ambiguity of some context-free languages, and apply it to give a purely combinatorial proof of the infinite ambiguity of Shamir’s language. Then we show how Ginsburg and Ullian’s criterion on unambiguous bounded languages translates into a useful criterion on generating series, which generalises and simplifies the proof of the recent criterion of Makarov [Vladislav Makarov, 2021]. We then propose a new criterion based on generating series to prove the inherent ambiguity of languages with interlacing patterns, like {a^nb^ma^pb^q | n≠p or m≠q, with n,m,p,q ∈ ℕ^*}. We illustrate the applicability of these two criteria on many examples

Joining Forces in Boston: Community Development Corporations

In 2005, the Jewish Community Relations Council organized a Learning Exchange in which a group of Boston antipoverty leaders traveled to Israel with the goal of fostering cross-fertilization between the Boston delegation and their counterparts in Haifa. The Exchange achieved that goal remarkably. At the time, I was the director of a Boston-based community development corporation (CDC) that faced challenges related to rapid neighborhood change, and my experience spurred me to seek out opportunities for cross-fertilization and collaboration within greater Boston of the type we experienced in Haifa. Specifically, I brought colleagues together to share our experiences leading CDCs in a changing environment. Those conversations grew into the Community Development Innovation Forum, which engaged about eighty community development practitioners and allies in a process of rethinking our strategies and our field. As part of that process, and motivated by the Boston–Haifa experience, I devoted myself to exploring how collaborations can help CDCs be more effective and resilient. This article summarizes the observations and analysis that resulted from that exploration, which I believe are applicable to nonprofit and social change organizations more generally, particularly those that are place based