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

Violent and Criminal Behaviors in Rural and Non-Rural African American Youth: A Risk-Protective Factor Approach

Once believed to be a poor inner city neighborhood characteristic, youth violence and crime are now recognized as problems in rural areas as well (Osgood and Chambers 2000). Studies on their etiology remain scarce, particularly with a focus on minority youth. Given the importance of individual characteristics and a positive future orientation (educational aspirations) during adolescence, the current study tested a riskprotective factor approach with measures of risk proneness, self-esteem, educational commitment, and educational expectations to predict both direct and “indirect” measures of violence and criminal behaviors (assault, encounters with law enforcement, and court appearances) in samples of rural (n=687) and non-rural (n=182) African American youth. Results show that self-esteem, risk-proneness, and educational commitment were highly associated with measures of violent and criminal behaviors in both samples. Importantly, no differences were found in how risk or protective factors were associated with measures of violence and crime in rural and non-rural developmental contexts

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

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

Can current moisture responses predict soil CO2 efflux under altered precipitation regimes? A synthesis of manipulation experiments

As a key component of the carbon cycle, soil CO2 efflux (SCE) is being increasingly studied to improve our mechanistic understanding of this important carbon flux. Predicting ecosystem responses to climate change often depends on extrapolation of current relationships between ecosystem processes and their climatic drivers to conditions not yet experienced by the ecosystem. This raises the question of to what extent these relationships remain unaltered beyond the current climatic window for which observations are available to constrain the relationships. Here, we evaluate whether current responses of SCE to fluctuations in soil temperature and soil water content can be used to predict SCE under altered rainfall patterns. Of the 58 experiments for which we gathered SCE data, 20 were discarded because either too few data were available or inconsistencies precluded their incorporation in the analyses. The 38 remaining experiments were used to test the hypothesis that a model parameterized with data from the control plots (using soil temperature and water content as predictor variables) could adequately predict SCE measured in the manipulated treatment. Only for 7 of these 38 experiments was this hypothesis rejected. Importantly, these were the experiments with the most reliable data sets, i.e., those providing high-frequency measurements of SCE. Regression tree analysis demonstrated that our hypothesis could be rejected only for experiments with measurement intervals of less than 11 days, and was not rejected for any of the 24 experiments with larger measurement intervals. This highlights the importance of high-frequency measurements when studying effects of altered precipitation on SCE, probably because infrequent measurement schemes have insufficient capacity to detect shifts in the climate dependencies of SCE. Hence, the most justified answer to the question of whether current moisture responses of SCE can be extrapolated to predict SCE under altered precipitation regimes is 'no' - as based on the most reliable data sets available. We strongly recommend that future experiments focus more strongly on establishing response functions across a broader range of precipitation regimes and soil moisture conditions. Such experiments should make accurate measurements of water availability, should conduct high-frequency SCE measurements, and should consider both instantaneous responses and the potential legacy effects of climate extremes. This is important, because with the novel approach presented here, we demonstrated that, at least for some ecosystems, current moisture responses could not be extrapolated to predict SCE under altered rainfall conditions

Can current moisture responses predict soil CO2 efflux under altered precipitation regimes? A synthesis of manipulation experiments.

As a key component of the carbon cycle, soil CO2 efflux (SCE) is being increasingly studied to improve our mechanistic understanding of this important carbon flux. Predicting ecosystem responses to climate change often depends on extrapolation of current relationships between ecosystem processes and their climatic drivers to conditions not yet experienced by the ecosystem. This raises the question of to what extent these relationships remain unaltered beyond the current climatic window for which observations are available to constrain the relationships. Here, we evaluate whether current responses of SCE to fluctuations in soil temperature and soil water content can be used to predict SCE under altered rainfall patterns. Of the 58 experiments for which we gathered SCE data, 20 were discarded because either too few data were available or inconsistencies precluded their incorporation in the analyses. The 38 remaining experiments were used to test the hypothesis that a model parameterized with data from the control plots (using soil temperature and water content as predictor variables) could adequately predict SCE measured in the manipulated treatment. Only for 7 of these 38 experiments was this hypothesis rejected. Importantly, these were the experiments with the most reliable data sets, i.e., those providing high-frequency measurements of SCE. Regression tree analysis demonstrated that our hypothesis could be rejected only for experiments with measurement intervals of less than 11 days, and was not rejected for any of the 24 experiments with larger measurement intervals. This highlights the importance of high-frequency measurements when studying effects of altered precipitation on SCE, probably because infrequent measurement schemes have insufficient capacity to detect shifts in the climate dependencies of SCE. Hence, the most justified answer to the question of whether current moisture responses of SCE can be extrapolated to predict SCE under altered precipitation regimes is ?no? ? as based on the most reliable data sets available. We strongly recommend that future experiments focus more strongly on establishing response functions across a broader range of precipitation regimes and soil moisture conditions. Such experiments should make accurate measurements of water availability, should conduct high-frequency SCE measurements, and should consider both instantaneous responses and the potential legacy effects of climate extremes. This is important, because with the novel approach presented here, we demonstrated that, at least for some ecosystems, current moisture responses could not be extrapolated to predict SCE under altered rainfall conditions

Synthesis, X-ray Analysis, and Biological Evaluation of a New Class of Stereopure Lactam-Based HIV-1 Protease Inhibitors

In an effort to identify a new class of druglike HIV-1 protease inhibitors, four different stereopure beta-hydroxy gamma-lactam-containing inhibitors have been synthesized, biologically evaluated, and cocrystallized. The impact of the tether length of the central spacer (two or three carbons) was also investigated. A compound with a shorter tether and (3R,4S) absolute configuration exhibited high activity with a K-i of 2.1 nM and an EC50 of 0.64 mu M. Further optimization by decoration of the P1' side chain furnished an even more potent HIV-1 protease inhibitor (K-i = 0.8 nM, EC50 = 0.04 mu M). According to X-ray analysis, the new class of inhibitors did not fully succeed in forming two symmetric hydrogen bonds to the catalytic aspartates. The crystal structures of the complexes further explain the difference in potency between the shorter inhibitors (two-carbon spacer) and the longer inhibitors (three-carbon spacer)

Can Current Moisture Responses Predict Soil CO2 Efflux Under Altered Precipitation Regimes? A Synthesis of Manipulation Experiments

As a key component of the carbon cycle, soil CO2 efflux (SCE) is being increasingly studied to improve our mechanistic understanding of this important carbon flux. Predicting ecosystem responses to climate change often depends on extrapolation of current relationships between ecosystem processes and their climatic drivers to conditions not yet experienced by the ecosystem. This raises the question to what extent these relationships remain unaltered beyond the current climatic window for which observations are available to constrain the relationships. Here, we evaluate whether current responses of SCE to fluctuations in soil temperature and soil water content can be used to predict SCE under altered rainfall patterns. Of the 58 experiments for which we gathered SCE data, 20 were discarded because either too few data were available, or inconsistencies precluded their incorporation in the analyses. The 38 remaining experiments were used to test the hypothesis that a model parameterized with data from the control plots (using soil temperature and water content as predictor variables) could adequately predict SCE measured in the manipulated treatment. Only for seven of these 38 experiments, this hypothesis was rejected. Importantly, these were the experiments with the most reliable datasets, i.e., those providing high-frequency measurements of SCE. Accordingly, regression tree analysis demonstrated that measurement frequency was crucial; our hypothesis could be rejected only for experiments with measurement intervals of less than 11 days, and was not rejected for any of the 24 experiments with larger measurement intervals. This highlights the importance of high-frequency measurements when studying effects of altered precipitation on SCE, probably because infrequent measurement schemes have insufficient capacity to detect shifts in the climate-dependencies of SCE. We strongly recommend that future experiments focus more strongly on establishing response functions across a broader range of precipitation regimes and soil moisture conditions. Such experiments should make accurate measurements of water availability, they require high-frequency SCE measurements and they should consider both instantaneous responses and the potential legacy effects of climate extremes. This is important, because we demonstrated that at least for some ecosystems, current moisture responses cannot be extrapolated to predict SCE under altered rainfall

Endocrinologic, neurologic, and visual morbidity after treatment for craniopharyngioma

Craniopharyngiomas are locally aggressive tumors which typically are focused in the sellar and suprasellar region near a number of critical neural and vascular structures mediating endocrinologic, behavioral, and visual functions. The present study aims to summarize and compare the published literature regarding morbidity resulting from treatment of craniopharyngioma. We performed a comprehensive search of the published English language literature to identify studies publishing outcome data of patients undergoing surgery for craniopharyngioma. Comparisons of the rates of endocrine, vascular, neurological, and visual complications were performed using Pearson’s chi-squared test, and covariates of interest were fitted into a multivariate logistic regression model. In our data set, 540 patients underwent surgical resection of their tumor. 138 patients received biopsy alone followed by some form of radiotherapy. Mean overall follow-up for all patients in these studies was 54 ± 1.8 months. The overall rate of new endocrinopathy for all patients undergoing surgical resection of their mass was 37% (95% CI = 33–41). Patients receiving GTR had over 2.5 times the rate of developing at least one endocrinopathy compared to patients receiving STR alone or STR + XRT (52 vs. 19 vs. 20%, χ2P < 0.00001). On multivariate analysis, GTR conferred a significant increase in the risk of endocrinopathy compared to STR + XRT (OR = 3.45, 95% CI = 2.05–5.81, P < 0.00001), after controlling for study size and the presence of significant hypothalamic involvement. There was a statistical trend towards worse visual outcomes in patients receiving XRT after STR compared to GTR or STR alone (GTR = 3.5% vs. STR 2.1% vs. STR + XRT 6.4%, P = 0.11). Given the difficulty in obtaining class 1 data regarding the treatment of this tumor, this study can serve as an estimate of expected outcomes for these patients, and guide decision making until these data are available

Leaf Trait-Environment Relationships in a Subtropical Broadleaved Forest in South-East China

Although trait analyses have become more important in community ecology, trait-environment correlations have rarely been studied along successional gradients. We asked which environmental variables had the strongest impact on intraspecific and interspecific trait variation in the community and which traits were most responsive to the environment. We established a series of plots in a secondary forest in the Chinese subtropics, stratified by successional stages that were defined by the time elapsed since the last logging activities. On a total of 27 plots all woody plants were recorded and a set of individuals of every species was analysed for leaf traits, resulting in a trait matrix of 26 leaf traits for 122 species. A Fourth Corner Analysis revealed that the mean values of many leaf traits were tightly related to the successional gradient. Most shifts in traits followed the leaf economics spectrum with decreasing specific leaf area and leaf nutrient contents with successional time. Beside succession, few additional environmental variables resulted in significant trait relationships, such as soil moisture and soil C and N content as well as topographical variables. Not all traits were related to the leaf economics spectrum, and thus, to the successional gradient, such as stomata size and density. By comparing different permutation models in the Fourth Corner Analysis, we found that the trait-environment link was based more on the association of species with the environment than of the communities with species traits. The strong species-environment association was brought about by a clear gradient in species composition along the succession series, while communities were not well differentiated in mean trait composition. In contrast, intraspecific trait variation did not show close environmental relationships. The study confirmed the role of environmental trait filtering in subtropical forests, with traits associated with the leaf economics spectrum being the most responsive ones