Accounting for Changing Inequality in Costa Rica, 1980-1999

After declining from the mid-1970s to the mid-1980s, earnings inequality in Costa Rica stabilized from 1987 to 1992 and then increased from 1992 to 1999. In this paper we use recently-developed techniques to measure the extent to which these changes in earnings inequality were the result of changes associated with the distributions (or .quantities.) of personal and work place characteristics of workers, and the earnings differences (or .prices.) associated with those characteristics. We present evidence that the most important cause of the fall in inequality prior to 1987 was a decline in returns to education, which in turn was caused by an increase in the supply of more-educated workers. We find that the most important causes of rising inequality in the 1990s were the end of this decline in returns to education and increases in the variance of hours worked among workers. Inequality in hours worked increased because of an increase in the proportion of workers working a non-standard work week (part-time or over-time)inequality, Latin America, labor

Use of sonic tomography to detect and quantify wood decay in living trees.

Premise of the studyField methodology and image analysis protocols using acoustic tomography were developed and evaluated as a tool to estimate the amount of internal decay and damage of living trees, with special attention to tropical rainforest trees with irregular trunk shapes.Methods and resultsLiving trunks of a diversity of tree species in tropical rainforests in the Republic of Panama were scanned using an Argus Electronic PiCUS 3 Sonic Tomograph and evaluated for the amount and patterns of internal decay. A protocol using ImageJ analysis software was used to quantify the proportions of intact and compromised wood. The protocols provide replicable estimates of internal decay and cavities for trees of varying shapes, wood density, and bark thickness.ConclusionsSonic tomography, coupled with image analysis, provides an efficient, noninvasive approach to evaluate decay patterns and structural integrity of even irregularly shaped living trees

Drainage divide migration and implications for climate and biodiversity

Drainage divides separate Earth’s surface into individual river basins. Divide migration impacts the evolution of landforms, regional climate, ecosystems and biodiversity. In this Review, we assess the processes and dynamics of divide migration and offer insights into the impact on climate and biodiversity. Drainage divides are not static: they can move through the processes of gradual migration that is continuous in unsteady landscapes, or sudden through infrequent river capture events. Divides tend to move in the direction of slower erosion, faster uplift or with horizontal tectonic advection, with rates typically ranging between 0.001 and 10 mm year−1, and a global average of 0.6 mm year−1. Evidence of river capture, such as a sharp change in flow direction with an upstream waterfall, can constrain divide migration history. Topographic metrics, such as cross-divide steepness, can predict the migration of drainage divides towards directions with a lower topographic steepness. Divide migration influences the spatial distribution of regional precipitation, temperature and topographic connectivity between species, thereby affecting biodiversity. For example, freshwater fish can migrate into a new drainage basin through river capture, potentially increasing the species richness. Future research should couple advanced landscape evolution models and observations from field and remote sensing to better investigate divide migration dynamics.</p

Volcanic Emissions and Atmospheric Pollution: A Study of Nanoparticles

The influence of emissions of an active volcano on the composition of nanoparticles and ultrafine road dust was identified in an urban area of the Andes. Although many cities are close to active volcanoes, few studies have evaluated their influence in road dust composition. Air quality in urban areas is significantly affected by non-exhaust emissions (e.g. road dust, brake wear, tire wear), however, natural sources such as volcanoes also impact the chemical composition of the particles. In this study, elements from volcanic emissions such as Si \u3e Al \u3e Fe \u3e Ca \u3e K \u3e Mg, and Si—Al with K were identified as complex hydrates. Similarly, As, Hg, Cd, Pb, As, H, Cd, Pb, V, and salammoniac were observed in nanoparticles and ultrafine material. Mineral composition was detected in the order of quartz\u3e mullite\u3e calcite\u3e kaolinite\u3e illite\u3e goethite\u3e magnetite\u3e zircon\u3e monazite, in addition to salammoniac, a tracer of volcanic sources. The foregoing analysis reflects the importance of carrying out more studies relating the influence of volcanic emissions in road dust in order to protect human health. The road dust load (RD10) ranged between 0.8 and 26.8 mg m−2 in the city

Volcanic emissions and atmospheric pollution: a study of nanoparticles

The influence of emissions of an active volcano on the composition of nanoparticles and ultrafine road dust was identified in an urban area of the Andes. Although many cities are close to active volcanoes, few studies have evaluated their influence in road dust composition. Air quality in urban areas is significantly affected by non-exhaust emissions (e.g. road dust, brake wear, tire wear), however, natural sources such as volcanoes also impact the chemical composition of the particles. In this study, elements from volcanic emissions such as Si > Al > Fe > Ca > K > Mg, and Si Al with K were identified as complex hydrates. Similarly, As, Hg, Cd, Pb, As, H, Cd, Pb, V, and salammoniac were observed in nanoparticles and ultrafine material. Mineral composition was detected in the order of quartz> mullite> calcite> kaolinite> illite> goethite> magnetite> zircon> monazite, in addition to salammoniac, a tracer of volcanic sources. The foregoing analysis reflects the importance of carrying out more studies relating the influence of volcanic emissions in road dust in order to protect human health. The road dust load (RD10) ranged between 0.8 and 26.8 mg m−2 in the city

ESTRUCTURA DEL MACROBENTOS EN LA PLAYA URBANA DE PANAMÁ VIEJO.

The macrofauna of urban sandy beaches has been little studied in the country, despite the ecological importance as a component of the trophic structure of the coastal ecosystem of beaches that receive flocks of migratory birds at a specific time of year, and sewage and surface water from the urban rivers. The abundance and diversity of benthic macroinvertebrates of Panama Viejo beach was determined in three seasons and evaluated during four months of the rainy season. Variations in dissolved oxygen of the interstitial fluid were observed between 7.16 and 9.09 mg/l, dissolved solids, average 0.21 0.18 mg/L, sediment temperature between 27 and 37°C, mean salinity of 28.83 1.10 and organic matter of 2,25 1.36 %. The particle size was represented by very coarse and coarse sand, separating the samples into four groups according to the mean Mz, representing the three study areas. 640 organisms were collected from 19 taxa, the hierarchy was represented by polychaetes &gt; mollusks&gt; crustaceans. The dominant group was Psamotreta grandis, followed by polychaetes Capitellidae. Shannon Wiener’s diversity varied between 1.16 and 2.34 nats/ind. The Playa station was more diverse and better structured, and the Museum station was more abundant. The dominant trophic groups were sub-surface and surface detritivores, indicating a stressed zone. The trophic index of infancy (ITI) was 30.29 which indicates a bordering environment between contaminated and degraded. &nbsp;La macrofauna de playas arenosas urbanas ha sido poco estudiada en el país, a pesar de la importancia ecológica como componente de la estructura trófica del ecosistema costero en particular de playas que reciben bandadas de aves migratorias en cierta época del año, y aportes de aguas servidas y superficiales provenientes de los ríos citadinos. Se determinó la abundancia y diversidad de macroinvertebrados bentónicos de la playa de Panamá Viejo, en tres estaciones, evaluadas durante cuatro meses de la temporada lluviosa. Se observaron variaciones del oxígeno disuelto del líquido intersticial entre 7,16 a 9,09 mg/l, sólidos disueltos, promedio de 0,21 ± 0,18 mg/L, temperatura del sedimento entre 27 y 37 °C, salinidad promedio de 28,83 ± 1,10 ups y materia orgánica de 2,25 ± 1,36 %. La granulometría estuvo representada por arena muy gruesa y gruesa, lo cual separó las muestras en cuatro grupos de acuerdo con el gano medio Mz, que representan las tres zonas de estudio. Se recolectaron 640 organismos de 19 taxones, la jerarquía estuvo representada por poliquetos &gt; moluscos &gt; crustáceos. El grupo dominante fue Psamotreta grandis, seguido por poliquetos Capitellidae. La diversidad de Shannon Wiener varió entre 1,16 y 2,34 nats/ind. La estación Playa resultó ser más diversa y mejor estructurada, y la de Museo más abundante. Los grupos tróficos dominantes fueron los detritívoros de sub-superficie y superficie, lo cual indica una zona estresada. El índice trófico de la infauna (ITI) fue de 30,29 lo que indica un ambiente limítrofe entre contaminado y degradado

Jerarquía de valores de los estudiantes de Instituciones de Educación Superior

The present work consists of describing the hierarchy of values in the students of the International Business Program of the Faculty of Administrative, Economic and Accounting Sciences of the Luis Amigó Catholic University - Medellín - Colombia. The study is based on the theory of values assumed by Savater (2016); Spluga (2011); Merma et al, (2013); Trouriñán (2008) among others. The results obtained demonstrate the high importance that the students established to the values of respect, honesty, responsibility and happiness, while the students gave little importance to the values independence, capacity for reflection, work and tolerance. It can be concluded that the human being is shaping his values from childhood, with the family nucleus being the main influencing medium; followed by the social and cultural context with which they interact that defines their behaviors; therefore, the individual is in constant transformation processes in contact with the other.En el presente trabajo consiste en describir la jerarquía de los valores en los estudiantes del Programa Negocios Internacionales de la Facultad de Ciencias Administrativas, Económicas y Contables de la Universidad Católica Luis Amigó – Medellín - Colombia. El estudio se apoya en la teoría de valores asumida por Savater (2016); Spluga (2011); Merma et al, (2013); Trouriñán (2008) entre otros. Los resultados obtenidos demuestran la alta importancia que los estudiantes establecieron a los valores respeto, honradez, responsabilidad y felicidad mientras que los alumnos dan poca importancia a los valores independencia, capacidad de reflexión, trabajo y tolerancia. Se puede concluir que el ser humano va conformando sus valores desde la infancia, siendo el núcleo familiar en el principal medio influenciador; seguido por el contexto social y cultural con el que interactúa que le va definiendo sus conductas; por lo tanto, el individuo se encuentra en constante procesos de transformación en el contacto con el otro

Climate and vegetation dynamics of the last 6700 years in the Mistrató sector (western cordillera, Colombia).

Objetivo. Se presenta un estudio de la dinámica del clima y la vegetación del humedal Medellincito (5º 19’ 022”N y 75º54’ 515”W), localizado en el flanco occidental de la cordillera Occidental de Colombia a 2020 msnm. Alcance. El predominio del bosque Andino durante todo el registro indica que este creció en los alrededores inmediatos bajo condiciones casi permanentes de humedad. Sin embargo, eventos de menor precipitación se registraron alrededor de 6700, 5900, 5100, 4500, 4100-4300, 3200-1300, 1000-750 cal años AP, durante los cuales crecieron especies de vegetación abierta conformadas por Poaceae, Asteraceae, Ericaceae y Cyperaceae. La alta humedad del sitio puede deberse a la influencia constante de la corriente de chorro del Pacífico colombiano y de la Zona de Convergencia Intertropical (ZCIT). Aunque no hay evidencias directas de la acción del fenómeno El Niño de alto impacto en el occidente de Colombia, si puede especularse que los eventos más secos puedan tener alguna relación con este fenómeno. Resultados. Los registros de polen, esporas y diatomeas de los últimos ~6700 años cal AP muestran que la vegetación del bosque Andino estuvo dominada por Cyatheaceae, Hedyosmum (Chloranthaceae), Solanaceae, Viburnum, Miconia, Weinmannia y Myrsine, y el bosque Subandino por Fabaceae, Alchornea (Euphorbiaceae) y Bignoniaceae. Conclusiones. En los últimos ~150 cal años AP, el paisaje se ha modificado significativamente pasando de ser un bosque muy húmedo a bosque húmedo, reflejado en el drástico decrecimiento de Hedyosmum, Solanaceae y Cyatheaceae, y un incremento en la vegetación abierta, principalmente Poaceae junto a Cyperaceae en ambientes de pantano, debido a intervención antrópica (extracción selectiva de especies maderables y ganadería extensiva). Es posible que efectos negativos de advección de humedad por la corriente de Chorro hayan afectado la precipitación horizontal y con ello la disminución del bosque de niebla, característico de ecosistemas montanos bajos.Objective. Our research is focused on climate and vegetation dynamic recorded by the Medellincito wetland (5º 19 ‘022 “N and 75º54’ 515” W), located on the western flank of the Western cordillera of Colombia at 2020 masl. Scope. A predominance of the Andean forest along the entire core suggests that the wetland was established under almost permanent humidity conditions. Nevertheless, low precipitation events are also recorded around 6700, 5900, 5100, 4500, 4100-4,300, 3200-1300, and 1000-750 cal years AP, when open vegetation such as Poaceae, Asteraceae, Ericaceae and Cyperaceae occurred. The high humidity conditions interpreted for the studied site may be indicating the constant influence of the Pacific jet stream and the Intertropical Convergence Zone (ITCZ). Although there is no direct evidence of El Niño activity, which has a high impact on the western Colombia, we speculate that drier events identified in the Medellincito wetland may be related to this phenomenon. Results. The pollen, spore, and diatom records reveal that during the last ~ 6700 years Cal AP, the Andean forest vegetation was dominated by Cyatheaceae, Hedyosmum (Chloranthaceae), Solanaceae, Viburnum, Miconia, Weinmannia and Myrsine, and the Subandean forest by Fabaceae, Alchornea (Euphorbiaceae) and Bignoniaceae. Conclusions. In the last ~ 150 years cal BP, the landscape has significantly changed from a very humid to a humid forest. This is evidenced by the drastic decrease of Hedyosmum, Cyatheaceae, and Solanaceae, and the increase of open vegetation, mainly Poaceae and Cyperaceae in swamp environments, due to anthropic intervention (selective extraction of timber species and extensive livestock). It is possible that negative effects of humidity advection by the Jet stream, have affected the precipitation and, consequently, decreased the cloud forest characteristic of low montane ecosystems

Indirect measurement of pinch and pull forces at the shaft of laparoscopic graspers

The grasping instruments used in minimally invasive surgery reduce the ability of the surgeon to feel the forces applied on the tissue, thereby complicating the handling of the tissue and increasing the risk of tissue damage. Force sensors implemented in the forceps of the instruments enable accurate measurements of applied forces, but also complicate the design of the instrument. Alternatively, indirect estimations of tissue interaction forces from measurements of the forces applied on the handle are prone to errors due to friction in the linkages. Further, the force transmission from handle to forceps exhibits large nonlinearities, so that extensive calibration procedures are needed. The kinematic analysis of the grasping mechanism and experimental results presented in this paper show that an intermediate solution, force measurements at the shaft and rod of the grasper, enables accurate measurements of the pinch and pull forces on tissue with only a limited number of calibration measurements. We further show that the force propagation from the shaft and rod to the forceps can be approximated by a linear two-dimensional function of the opening angle of the grasper and the force on the rod