704 research outputs found
Water scarcity is exacerbated in the south
No full textThe Southern Hemisphere has experienced a 20% drop in water availability in 20 years
Drought‐Rich Periods Are More Likely Than Flood‐Rich Periods in Brazil
Full text linkStreamflow exhibits persistent decadal variability; however, it is unclear if the magnitude and spatial extent of these variabilities are symmetric for droughts and floods. Here, we examine drought‐rich and flood‐rich periods in 319 streamflow gauges in Brazil from 1940 to 2020. Drought‐ and flood‐rich periods are detected by computing annual streamflow minima and maxima time series and using scan statistics to verify if events exceeding a threshold follow a Bernoulli process. We contrast streamflow time clustering with rainfall, evaporation, water abstraction, the Atlantic Multidecadal Oscillation (AMO), and the Pacific Decadal Oscillation (PDO). We detected a higher spatial frequency of drought‐ than flood‐rich periods. For 5‐year return period thresholds, drought‐rich periods are observed in 81% of the basins, 16.7 times the false positive rate (4.8%) and 4.7 times flood‐rich periods (17%). This asymmetry is linked with sharp increases in water abstractions since the 1990s and a higher prevalence of rainfall‐poor periods (41% of gauges) compared to rainfall‐rich (22% of gauges), which we interpret as being further amplified into drought‐rich periods due to an interannual persistence of water storage deficits. Brazil experienced a dry period until the 1960s, extensive flooding in the 1980s, and record low flows from the 2000s onward. Drought and flood‐rich periods are well aligned with rainfall clustering, water abstractions, the AMO and PDO. Droughts‐rich periods are more frequent in shorter time scales (several years to one decade) and flood‐rich periods in longer time scales (a few decades). Our findings highlight the nonlinearity and asymmetry of drought and flood change at decadal scales
Process Controls on Flood Seasonality in Brazil
No full textA coincidence in the timing of floods and their drivers can be used as a proxy for the causality of flood generation. Here, we investigate the relationship between the seasonality of floods, maximum annual rainfall, and maximum annual soil moisture data of 886 basins in Brazil for 1980–2015 to shed light on process controls of flood generation. Floods tend to occur at the same time of year as soil moisture peaks and lag behind rainfall peaks by 3 weeks. In Amazonia, central and northern Brazil, flood timing is more correlated with the timing of soil moisture peaks than with that of rainfall peaks, which is interpreted as resulting from high subsurface water storage capacities. In southern and southeastern Brazil, on the other hand, flood timing is highly correlated with both soil moisture and rainfall because of low subsurface water storage capacities. These findings can support flood forecasting and climate impact studies
Climate and land management accelerate the Brazilian water cycle
Full text linkIncreasing floods and droughts are raising concerns of an accelerating water cycle, however, the relative contributions to streamflow changes from climate and land management have not been assessed at the continental scale. We analyze streamflow data in major South American tropical river basins and show that water use and deforestation have amplified climate change effects on streamflow extremes over the past four decades. Drying (fewer floods and more droughts) is aligned with decreasing rainfall and increasing water use in agricultural zones and occurs in 42% of the study area. Acceleration (both more severe floods and droughts) is related to more extreme rainfall and deforestation and occurs in 29% of the study area, including southern Amazonia. The regionally accelerating water cycle may have adverse global impacts on carbon sequestration and food security
Monitoramento e modelagem do processo de interceptação da chuva de uma bacia coberta por floresta ombrófila mista
Full text linkDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Ambiental, Florianópolis, 2015.A interceptação é o processo pelo qual a precipitação que cai sobre a superfície do terreno fica retida, é redistribuída ao solo ou evapora posteriormente. Esse processo é importante especialmente em áreas florestais, pois influencia na reciclagem da umidade do ar e também na quantidade de água que efetivamente chega ao solo. A maioria dos estudos de interceptação nas florestas brasileiras foi feita na região Amazônica e Mata Atlântica, mas poucos foram os estudos realizados na Mata Atlântica do tipo Floresta Ombrófila Mista. O objetivo deste trabalho foi compreender e estimar os processos de interceptação da chuva em uma bacia coberta por Floresta Ombrófila Mista por meio de monitoramento e modelagem. A perda por interceptação (I) foi estimada por meio da medição de chuva externa (P), chuva interna (Tf) e escoamento pelo tronco (Sf). O monitoramento da chuva externa foi feito com três pluviômetros e um pluviógrafo instalados fora da bacia. Nove pluviômetros e uma calha interligada a um pluviógrafo foram instalados para o monitoramento da chuva interna. O monitoramento do escoamento pelo tronco foi realizado em dez árvores interligadas a um recipiente de armazenamento e mais quatro árvores interligadas a um pluviógrafo. Os índices de cobertura do dossel foram estimados a partir de fotografias do dossel. Os dados hidrometeorológicos foram monitorados na estação meteorológica do Rio Feio. A chuva externa nos três anos de monitoramento somou 5.309 mm distribuídos em 321 eventos e houve 489 dias sem ocorrência de chuva. Os modelos de Rutter esparso e de Gash esparso foram utilizados para a modelagem do processo de interceptação. A chuva interna variou de 61 a 83% da chuva externa, o que demonstrou que a chuva interna é heterogênea na bacia coberta por Floresta Ombrófila Mista. O volume de escoamento de tronco variou de 0,1 a 22,9 litros, com média de 2,92 litros e no período monitorado os volumes tenderam a crescer com o aumento do diâmetro do tronco e da área da copa. O índice de cobertura do dossel na bacia variou de 45 a 94%, com média de 80% e não apresentou correlação com a distribuição da chuva interna. Os dados automatizados da chuva interna e escoamento pelo tronco foram distribuídos em 60 eventos, a chuva externa foi 1.303 mm, a chuva interna e escoamento pelo tronco corresponderam a 75% (981 mm) e 2 % (19 mm) da chuva externa. A média da evapotranspiração potencial da série calculada foi de 1,09 mm dia-1. O erro relativo por evento dos modelos de interceptação variou de 2 a 400% para o modelo de Rutter e de 0 a 350% para o modelo de Gash. O modelo de Gash subestimou a I acumulada enquanto que o modelo de Rutter a superestimou. A simulação com o modelo de Rutter foi a que obteve os menores valores do erro relativo (4%) em relação a I acumulada. Os dois modelos tiveram limitações para representar o processo de interceptação em eventos extremos, possivelmente devido aos erros associados à estrutura dos modelos assim como ao conjunto de dados medidos e estimados.Abstract :The interception is the process by which the precipitation that falls on the ground surface is retained, it is redistributed to the ground or evaporate later. This process is important especially in forested areas since it influences recycling of moisture from the air and also the amount of water that effectively reaches the ground. Most of the interception studies in Brazilian Forests were carried out in the Amazon and Atlantic Forest, but few have been conducted in the Atlantic Forest Mixed Ombrophilous Forest type. The objective of this work was to understand and estimate the process of interception of rain in an experimental catchment covered by Mixed Ombrophilous Forest through monitoring and modeling. The interception loss will be estimated by measuring rainfall (P), throughfall (Tf) and stemflow (Sf). The monitoring consists of three rain gauges and automatic rain gauge installed outside the basin for rainfall monitoring. Nine gauges and one trough-type collectors coupled to a rain gauge for throughfall monitoring. The stemflow monitoring was conducted in ten trees connected to a storage container and four trees connected to a rain gauge. The canopy cover fraction was estimated using photographs taken of the canopy. Hydrometeorological data were acquired with a meteorological station of Rio Feio. The Rutter and Gash models were used to model the interception process. The total rainfall monitoring of the complete 3 years was 5.309 mm, from 321 rainfall events and in 489 days there was no rainfall. The throughfall ranged from 61 to 83% the rainfall, which showed the throughfall heterogeneity. The stemflow ranged from 0,1 to 22,9 liters, averaging 2,92 liters and the volumes tend to increase with the diameters at breast height and crown area increases. The canopy cover fraction ranged from 45 to 94 %, averaging 80%. The calculation of the interception loss using automated date rail and stemflow were distributed in 60 events. The rainfall (P) was 1303 mm, Tf and Sf corresponded to 75% (981 mm) and 2% (19 mm) of P. The mean potential evapotranspiration was 1.09 mm day-1. The relative error in the models for the events ranged from 2 to 400% for the Rutter model and 0 to 350% for the Gash model. The Gash model underestimated I while the simulation of the Rutter model overestimated. The simulation with the Rutter model was the one with the lowest values of relative error (4%) for I accumulated. Both models have limitations to identify the process of interception
Water scarcity is exacerbated in the south
No full textThe Southern Hemisphere has experienced a 20% drop in water availability in 20 years
Polychaete infestation in cultured abalone (Haliotis rufescens Swainson) in Southern Chile
No full textPT: J; CR: BERTRAN C, 2005, IN PRESS SCI MARINA CACERESMARTINEZ J, 1998, J SHELLFISH RES, V17, P259 CIOCCO NF, 1990, BIOL PESQUERA, V19, P9 CLARKE KR, 1994, CHANGES MARINE COMMU GODOY C, 1998, J SHELLFISH RES, V17, P603 HADLEY SJ, 1997, AQUACULTURE, V153, P191 KOJIMA H, 1982, B JAP SOC SCI FISH, V48, P31 KURIS AM, 1999, INVERTEBR BIOL, V118, P391 LEIGHTON DL, 1998, J SHELLFISH RES, V17, P701 LLEONART M, 2003, AQUACULTURE, V221, P85 MARTIN D, 1998, OCEANOGRAPHY MARINE, V36, P217 MARTINEZ JC, 2000, J SHELLFISH RES, V19, P503 OWEN B, 1984, VELIGER, V27, P101 RADASHEVSKY V, 2005, IN PRESS BIOL INVASI ROZBACZYLO N, 1996, J MED APPL MALACOLOG, V8, P98 RUCK KR, 1998, J SHELLFISH RES, V17, P693 SATOOKOSHI W, 1999, J MAR BIOL ASSOC UK, V79, P831 SATOOKOSHI W, 2001, B MAR SCI, V68, P485 WARGO RN, 1993, ESTUARIES, V16, P229; NR: 19; TC: 1; J9: AQUAC RES; PG: 4; GA: 922VBSource type: Electronic(1
Las relaciones intertextuales en la tratadística político-pedagógica de Pedro de Ribadeneira y Juan de Mariana
Full text linkThe works of Pedro de Ribadeneira and Juan de Mariana will be revised and analysed in the following article. The focus will be on their political and pedagogical treatises, such as the Tratado de la Religión y Virtudes by the former and the books De Rege et Regis institutione by the latter author. The analysis of sources and similarities between excerpts will shed light on the intertextual relationship between these authors and their publications. Their lives and historiographical works will be introduced too, being the origin of the above-mentioned publications.
Supporting Agencies
This article is part of two research projects, one funded by the Ministry of Science, Innovation and Universities of the Government of Spain [Project Code: PGC2018-094604-B-C3] and the other funded by the Ministry of Economy and Competitiveness of the Government of Spain [Project code: FFI2017-90831-REDT].En el siguiente trabajo proponemos una revisión de las obras de los padres jesuitas Pedro de Ribadeneira y Juan de Mariana, especialmente del Tratado de la Religión y Virtudes que deue tener el Príncipe Christiano (Madrid, 1595) y de los libros De Rege et Regis institutione (primera edición en Toledo, 1599), escritos por uno y otro respectivamente. A través de un análisis filológico de las fuentes empleadas y de pasajes similares, aportamos datos para una comprensión conjunta de estas obras dentro del género político-pedagógico. De forma previa introducimos la obra historiográfica de ambos autores, germen de las obras arriba mencionadas.
Agencias de apoyo
Este artículo se enmarca en dos proyectos de investigación, uno financiado por el Ministerio de Ciencia, Innovación y Universidades del Gobierno de España [Ref. del proyecto: PGC2018-094604-B-C3] y el otro financiado por el Ministerio de Economía y Competitividad del Gobierno de España [Ref. del proyecto: FFI2017-90831-REDT].Dans l’article suivant, nous proposons une révision du Tratado de la Religión y Virtudes que deue tener el Príncipe Christiano (Madrid, 1595) de Pedro de Ribadeneira et du De Rege et Regis institutione (première édition à Tolède, 1599) de Juan de Mariana, tous les deux pères jésuites. Grâce à une analyse philologique des sources utilisées et des passages similaires, nous fournissons des données pour une compréhension commune de ces œuvres au sein du genre politico-pédagogique. D’avance, nous présentons le travail historiographique des deux auteurs, qui est à l’origine des ouvrages susmentionnés.
Organismes de soutien
Cet article fait partie de deux projets de recherche, l\u27un financé par le Ministère de la Science, de l\u27Innovation et des Universités du gouvernement espagnol [Code du projet : PGC2018-094604-B-C3] et l\u27autre financé par le Ministère de l\u27Économie et de la Compétitivité du gouvernement espagnol [Code du projet : FFI2017-90831-REDT]
A new economic journals’ ranking that takes into account the number of pages and co-authors
Full text linkIn this article, I examine whether the academics reward policy must correlate positively with the number of published articles per co-author, the number of pages and journal reputation. This is accomplished by estimating a non-linear model with a panel data from 168 economics journals covered in the ISI-Web of Knowledge database (58825 articles). The data reinforces the conjecture that published article value is slightly increasing with the number of co-authors and is proportional to the number of pages. The data also suggests that there are 4 distinct groups related to journal quality that I name A, B+, B and B–.Co-authorship, Value of articles, Assessment of output
Ichthyologists of Argentina: José Pedro Mestre Aceredillo
No full textThis series will include all those people who, by means of their contributions, great and small, played a part in the consolidation of ichthyology in Argentina.The general plan of this work consists of individual factsheets containing a list of works by each author, along with reference bibliography and, whenever possible,personal pictures and additional material.The datasheets will be published primarily in chronological order, although this is subject to change by the availability of materials for successive editions.This work represents another approach for the recovery and revalorization of those who set the foundations of Argentine ichthyology while in diverse historical circumstances.I expect this to be the beginning of a major work that achieves the description of such a significant part of the history of natural sciences in Argentina.ProBiota Programa para el estudio y uso sustentable de la biota australDebe citarse:
López, H. L.; S. B. Sverlij & J. Ponte Gómez. 2011. Ictiólogos de la Argentina: José Pedro Mestre Aceredillo. ProBiota, FCNyM, UNLP, La Plata, Argentina,Serie Técnica y
Didáctica 14(23): 1-23. ISSN 1515-9329
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