Cross-section and panel estimates of peer effects in early adolescent cannabis use: With a little help from my ‘friends once removed’

Peer effects in adolescent cannabis are difficult to estimate, due in part to the lack of appropriate data on behaviour and social ties. This paper exploits survey data that have many desirable properties and have not previously been used for this purpose. The data set, collected from teenagers in three annual waves from 2002-2004 contains longitudinal information about friendship networks within schools (N = 5,020). We exploit these data on network structure to estimate peer effects on adolescents from their nominated friends within school using two alternative approaches to identification. First, we present a cross-sectional instrumental variable (IV) estimate of peer effects that exploits network structure at the second degree, i.e. using information on friends of friends who are not themselves ego’s friends to instrument for the cannabis use of friends. Second, we present an individual fixed effects estimate of peer effects using the full longitudinal structure of the data. Both innovations allow a greater degree of control for correlated effects than is commonly the case in the substance-use peer effects literature, improving our chances of obtaining estimates of peer effects than can be plausibly interpreted as causal. Both estimates suggest positive peer effects of non-trivial magnitude, although the IV estimate is imprecise. Furthermore, when we specify identical models with behaviour and characteristics of randomly selected school peers in place of friends’, we find effectively zero effect from these ‘placebo’ peers, lending credence to our main estimates. We conclude that cross-sectional data can be used to estimate plausible positive peer effects on cannabis use where network structure information is available and appropriately exploited.

Room for Writing: How to write an abstract

An introductory exercise for writing abstracts Includes background, references and further reading

Comunicador Táctil ONCE: premio de investigación en deficiencias auditivas FIAPAS 2014, Área Accesibilidad

Las personas sordociegas se encuentran con dificultades para la comunicación presencial debidas a la imposibilidad de compartir información con interlocutores desconocidos o semidesconocidos que, en general, no saben o no dominan las formas y sistemas alternativos de comunicación utilizados por ellas. La tecnología actual y, en particular, los dispositivos móviles, ha permitido el desarrollo de este proyecto, cuya finalidad es la de ofrecer una nueva vía de comunicación en las citadas situaciones. Se han utilizado teléfonos inteligentes y tabletas (iPhone, iPad y dispositivos con Android) como canal para el proceso comunicativo que se produce entre dos personas. La aplicación desarrollada pretende recrear la comunicación entre dos personas, una de las cuales es sordociega. Para el interlocutor sordociego se han tenido en cuenta dos perfiles de usuario: personas sordociegas que son sordas pero que tienen visión limitada que les permite leer los mensajes del teléfono aunque sea ampliando el tamaño de los mismos, y otro perfil de personas sordociegas que son igualmente sordas pero también ciegas totales y que utilizarán un revisor de pantallas para acceder a la información que muestre la aplicación.

Dolarización oficial de la economía : un debate en once actos

El presente trabajo persigue varios objetivos entrelazados entre sí. En primer lugar, busca informar sobre la dolarización oficial, definiendo y diferenciándola de la dolarización espontánea, los lugares en que se ha dado y sus principales diferencias con otros regímenes cambiarios. En segundo lugar, pretende presentar los argumentos que se han formulado a su favor o en su contra, considerando las realidades latinoamericanas, si bien se le ha dado un sesgo, teniendo presente principalmente el caso peruano. En tercer lugar, se quieren dar a conocer los diversos economistas que han escrito en torno al tema y que han tomado posición en torno a él, para lo cual también se ha añadido una bibliografía relativamente exhaustiva. Ésta le permitirá al lector interesado profundizar en los detalles y matices diferenciales existentes entre los economistas, políticos y periodistas que se han expresado sobre la materia. Finalmente, se ha querido dar una lectura ideológica y geopolítica a la propuesta dolarizadora, tratando de auscultar a los beneficiarios, los perjudicados y las consecuencias del proceso4. En este último sentido, si bien nos centraremos en la argumentación económica en torno a la dolarización, es evidente que el tema está colmado de aristas políticas, sociales y hasta culturales, algunas de las cuales se translucirán en el guión que sigue. Sin embargo, por la propia naturaleza del trabajo, muchos temas de la dolarización plena, así como varios otros -estrechamente ligados a ella- han tenido que ser relegados a un segundo plano, tratándose marginalmente en el texto que sigue o sencillamente han sido suprimidos de él5. De ahí que resulte indispensable que el propio lector se aproxime más al tema, familiarizándose con la bibliografía anexa.

Dise?o de una secuencia did?ctica para la ense?anza del sistema digestivo en estudiantes entre los siete y once a?os de edad

El presente trabajo se ha centrado en resolver la siguiente pregunta ?C?mo dise?ar una secuencia did?ctica del sistema digestivo a partir de las concepciones en ni?os entre los siete y once a?os de edad? Para resolver esta pregunta se dise?aron una serie de actividades de forma organizadas y estructuradas que hacen parte de una secuencia did?ctica a partir de las concepciones de los estudiantes sobre el sistema digestivo, adem?s se tuvo en cuenta el desarrollo cognitivo de los estudiantes, esta propuesta fue adaptada a las necesidades educativas que surgieron de las imprecisiones de los estudiantes en sus concepciones sobre el sistema digestivo. Esta secuencia did?ctica se encuentra estructurada en tres fases, la primera fase es la de apertura, son actividades que permiten identificar y recoger las ideas previas de los estudiantes sobre el sistema digestivo, para as? poder personalizar las actividades de la segunda fase que son las de desarrollo, estas actividades son dise?adas para anclar al estudiantes con los nuevos conocimientos pero tambi?n relacionando los resultados que se obtuvieron en la fase de apertura y la tercera fase es la de cierre, fase donde las actividades fueron dise?adas para que los estudiantes recapitulen lo que realizaron en las anteriores fases.

An?lisis cr?tico de las pr?cticas letradas vern?culas de un grupo de j?venes de grado once de un colegio p?blico de Cali: El caso de los memes en Facebook [recurso electr?nico]

RESUMEN: En este trabajo de investigaci?n se presentan los resultados de una indagaci?n sobre las relaciones existentes entre las pr?cticas letradas vern?culas y las pr?cticas letradas acad?micas que se originan en la publicaci?n de memes en una p?gina de Facebook por parte de estudiantes de grado once en una instituci?n p?blica de la ciudad de Cali. En este escrito se analiza el papel que juegan los memes como texto multimodal en una red social y como en su uso se muestran las tensiones de los sujetos informantes frente al mundo escolar. En el estudio se hace un seguimiento a las profundas transformaciones en los modos de leer y escribir como resultado de las tecnolog?as digitales y las redes sociales, y que a trav?s de los discursos multimodales los sujetos construyen nuevas formas de leer el mundo escolar. El corpus est? constituido por el an?lisis de 10 memes y una serie de entrevistas en profundidad a 6 informantes que fueron grabadas y transcritas siguiendo el modelo de an?lisis del discurso cr?tico. El estudio de corte cualitativo-etnogr?fico arroja como resultados que los j?venes de grado once de una instituci?n p?blica ven tensionadas sus pr?cticas escolares por las pr?cticas de tipo institucional.

Established corticosteroid creams should be applied only once daily in patients with atopic eczema

Atopic eczema affects many adults and up to 20% of children,1 with health costs comparable to diabetes2 and asthma.3 One community survey of 1760 young children in the United Kingdom found that 84% had mild eczema, 14% moderate, and 2% severe eczema.4 Topical corticosteroids are a mainstay of treatment for inflammatory episodes.5 Most long established topical corticosteroids such as betamethasone valerate or hydrocortisone are applied at least twice daily, but three newer preparations (mometasone, fluticasone, and methylprednisolone) have been developed for once daily application. Here, I propose that established preparations need be applied only once daily.

Direct Write Fabrication of Waveguides and Interconnects for Optical Printed Wiring Boards

Current copper based circuit technology is becoming a limiting factor in high speed data transfer applications as processors are improving at a faster rate than are developments to increase on board data transfer. One solution is to utilize optical waveguide technology to overcome these bandwidth and loss restrictions. The use of this technology virtually eliminates the heat and cross-talk loss seen in copper circuitry, while also operating at a higher bandwidth. Transitioning current fabrication techniques from small scale laboratory environments to large scale manufacturing presents significant challenges. Optical-to-electrical connections and out-of-plane coupling are significant hurdles in the advancement of optical interconnects. The main goals of this research are the development of direct write material deposition and patterning tools for the fabrication of waveguide systems on large substrates, and the development of out-of-plane coupler components compatible with standard fiber optic cabling. Combining these elements with standard printed circuit boards allows for the fabrication of fully functional optical-electrical-printed-wiring-boards (OEPWBs). A direct dispense tool was designed, assembled, and characterized for the repeatable dispensing of blanket waveguide layers over a range of thicknesses (25-225 µm), eliminating waste material and affording the ability to utilize large substrates. This tool was used to directly dispense multimode waveguide cores which required no UV definition or development. These cores had circular cross sections and were comparable in optical performance to lithographically fabricated square waveguides. Laser direct writing is a non-contact process that allows for the dynamic UV patterning of waveguide material on large substrates, eliminating the need for high resolution masks. A laser direct write tool was designed, assembled, and characterized for direct write patterning waveguides that were comparable in quality to those produced using standard lithographic practices (0.047 dB/cm loss for laser written waveguides compared to 0.043 dB/cm for lithographic waveguides). Straight waveguides, and waveguide turns were patterned at multimode and single mode sizes, and the process was characterized and documented. Support structures such as angled reflectors and vertical posts were produced, showing the versatility of the laser direct write tool. Commercially available components were implanted into the optical layer for out-of-plane routing of the optical signals. These devices featured spherical lenses on the input and output sides of a total internal reflection (TIR) mirror, as well as alignment pins compatible with standard MT design. Fully functional OEPWBs were fabricated featuring input and output out-of-plane optical signal routing with total optical losses not exceeding 10 dB. These prototypes survived thermal cycling (-40°C to 85°C) and humidity exposure (95±4% humidity), showing minimal degradation in optical performance. Operational failure occurred after environmental aging life testing at 110°C for 216 hours.

INCORPORATING STIMULATING QUICK-WRITE PROMPTS WITHIN A SECONDARY SCIENCE CLASSROOM: A CASE STUDY IN LESOTHO

The use of intriguing open-ended quick-write prompts within the Basotho science classroom could potentially provide a way for secondary teachers in Lesotho to have a time-efficient alternative to stimulate student thinking and increase critical thinking or application of scientific principles. Writing can be used as a powerful means to improve the achievement of students across many subject areas, including the sciences (Moore, 1993; Rivard, 1994; Rillero, Zambo, Cleland, and Ryan, 1996; Greenstein, 2013). This study focuses on the use of a non-traditional nor extensively studied writing method that could potentially support learning in science. A quasi-experimental research design, with a control and experimental group, was applied. The study was conducted at two schools, with one experimental classroom in one school and a second control group classroom in the second school for a period of 4 weeks. 51 Form B (US Grade 9 equivalent) students participated as the experimental group and 43 Form B students as the control group. In an effort to assess learning achievement, a 1 hour (35 mark) pre-test evaluation was made by and given to students by Basotho teachers at the beginning of this study to have an idea of student’s previous knowledge. Topics covered were Static Electricity, Current Electricity, Electromagnetic Waves, and Chemistry of Water. After the experimental trial period, an almost completely identical post-test evaluation was given to students in the same fashion to observe and compare gains in achievement. Test data was analyzed using an inferential statistics procedure that compared means and gains in knowledge made by the experimental and control groups. Difference between the gains of mean pre-test and post-test scores were statistically significant within each group, but were not statistically significant when the control and experimental groups were compared. Therefore, there was no clear practical effect. Qualitative data from teachers’ journals and students’ written feedback provides insight on the assessments, incorporation of the teaching method, and the development of participating students. Both mid and post-study student feedback shows that students had an overall positive and beneficial experience participating in this activity. Assessments and teacher journals showed areas of strength and weaknesses in student learning and on differences in teaching styles. They also helped support some feedback claims made by students. Areas of further research and improvement of the incorporation of this teaching method in the Basotho secondary science classroom are explored.

[theoretical Construction In The Sociology Of Health: A Reflection On Its Trajectory].

The scope of this paper is to reflect on the theoretical construction in the constitution of the sociology of health, still called medical sociology in some countries. Two main ideas constitute the basis for this: interdisciplinarity and the degree of articulation in the fields of medicine and sociology. We sought to establish a dialogue with some dimensions - macro/micro, structure/action - that constitute the basis for understanding medicine/health in relation to the social/sociological dimension. The main aspects of these dimensions are initially presented. Straus' two medical sociologies and the theory/application impasses are then addressed, as well as the dilemmas of the sociology of medicine in the 1960s and 1970s. From these analyses the theoretical production before 1970 is placed as a counterpoint. Lastly, the sociology of health is seen in the general context of sociology, which underwent a fragmentation process from 1970 with effects in all subfields of the social sciences. This process involves a rethinking of the theoretical issues in a broadened spectrum of possibilities. The 1980s are highlighted when theoretical issues in the sociology of health are reinvigorated and the issue of interdisciplinarity is once again addressed.

[the Sociology Of Health In Brazil - The Creation Of An Identity].

This article analyzes the historical, social and cognitive dimensions of the sociology of medicine in the construction of its identity, from Wolf Lepenies' perspective. It is understood that the construction of an identity does not end with the first historical manifestations, but is consolidated when it is institutionalized and structured as a field of knowledge by creating its own forms of cognitive expression. The text is divided into three parts: in the first the precursors are presented, highlighting the role played by some travelers, naturalists and folklore scholars, followed by social physicians-scientists and the first social scientists (1940-1969). In the second part, aspects of the consolidation of the social sciences in health are presented at two significant moments, namely the 1970s and 1980s. In the third part, the issues raised by the field are addressed in general terms. It is considered that once the main structural stages are in place there is still a need for the formation of new generations of social scientists in health. It is also essential to disseminate scientific production and to ensure that the relations are studied in depth and institutionalized with the sociological matrices on the one hand and with the field of health on the other.

The Analgesic Effect Of Dipyrone In Peripheral Tissue Involves Two Different Mechanisms: Neuronal K(atp) Channel Opening And Cb(1) Receptor Activation.

Dipyrone (metamizole) is an analgesic pro-drug used to control moderate pain. It is metabolized in two major bioactive metabolites: 4-methylaminoantipyrine (4-MAA) and 4-aminoantipyrine (4-AA). The aim of this study was to investigate the participation of peripheral CB1 and CB2 cannabinoid receptors activation in the anti-hyperalgesic effect of dipyrone, 4-MAA or 4-AA. PGE2 (100ng/50µL/paw) was locally administered in the hindpaw of male Wistar rats, and the mechanical nociceptive threshold was quantified by electronic von Frey test, before and 3h after its injection. Dipyrone, 4-MAA or 4-AA was administered 30min before the von Frey test. The selective CB1 receptor antagonist AM251, CB2 receptor antagonist AM630, cGMP inhibitor ODQ or KATP channel blocker glibenclamide were administered 30min before dipyrone, 4-MAA or 4-AA. The antisense-ODN against CB1 receptor expression was intrathecally administered once a day during four consecutive days. PGE2-induced mechanical hyperalgesia was inhibited by dipyrone, 4-MAA, and 4-AA in a dose-response manner. AM251 or ODN anti-sense against neuronal CB1 receptor, but not AM630, reversed the anti-hyperalgesic effect mediated by 4-AA, but not by dipyrone or 4-MAA. On the other hand, the anti-hyperalgesic effect of dipyrone or 4-MAA was reversed by glibenclamide or ODQ. These results suggest that the activation of neuronal CB1, but not CB2 receptor, in peripheral tissue is involved in the anti-hyperalgesic effect of 4-aminoantipyrine. In addition, 4-methylaminoantipyrine mediates the anti-hyperalgesic effect by cGMP activation and KATP opening.

Optical And Nonoptical Aids For Reading And Writing In Individuals With Acquired Low Vision.

To evaluate the use of optical and nonoptical aids during reading and writing activities in individuals with acquired low vision. This study was performed using descriptive and cross-sectional surveys. The data collection instrument was created with structured questions that were developed from an exploratory study and a previous test based on interviews, and it evaluated the following variables: personal characteristics, use of optical and nonoptical aids, and activities that required the use of optical and nonoptical aids. The study population included 30 subjects with acquired low vision and visual acuities of 20/200-20/400. Most subjects reported the use of some optical aids (60.0%). Of these 60.0%, the majority (83.3%) cited spectacles as the most widely used optical aid. The majority (63.3%) of subjects also reported the use of nonoptical aids, the most frequent ones being letter magnification (68.4%), followed by bringing the objects closer to the eyes (57.8%). Subjects often used more than one nonoptical aid. The majority of participants reported the use of optical and nonoptical aids during reading activities, highlighting the use of spectacles, magnifying glasses, and letter magnification; however, even after the use of these aids, we found that the subjects often needed to read the text more than once to understand it. During writing activities, all subjects reported the use of optical aids, while most stated that they did not use nonoptical aids for such activities.

Effect Of Daily Use Of An Enzymatic Denture Cleanser On Candida Albicans Biofilms Formed On Polyamide And Poly(methyl Methacrylate) Resins: An In Vitro Study.

Candida biofilms on denture surfaces are substantially reduced after a single immersion in denture cleanser. However, whether this effect is maintained when dentures are immersed in cleanser daily is unclear. The purpose of this study was to evaluate the effect of the daily use of enzymatic cleanser on Candida albicans biofilms on denture base materials. The surfaces of polyamide and poly(methyl methacrylate) resin specimens (n=54) were standardized and divided into 12 groups (n=9 per group), according to study factors (material type, treatment type, and periods of treatment). Candida albicans biofilms were allowed to form over 72 hours, after which the specimens were treated with enzymatic cleanser once daily for 1, 4, or 7 days. Thereafter, residual biofilm was ultrasonically removed and analyzed for viable cells (colony forming units/mm(2)) and enzymatic activity (phospholipase, aspartyl-protease, and hemolysin). Factors that interfered with the response variables were analyzed by 3-way ANOVA with the Holm-Sidak multiple comparison method (α=.05). Polyamide resin presented more viable cells of Candida albicans (P<.001) for both the evaluated treatment types and periods. Although enzymatic cleansing significantly (P<.001) reduced viable cells, daily use did not maintain this reduction (P<.001). Phospholipase activity significantly increased with time (P<.001) for both materials and treatments. However, poly(methyl methacrylate) based resin (P<.001) and enzymatic cleansing treatment (P<.001) contributed to lower phospholipase activity. Aspartyl-protease and hemolysin activities were not influenced by study factors (P>.05). Although daily use of an enzymatic cleanser reduced the number of viable cells and phospholipase activity, this treatment was not effective against residual biofilm over time.