RESUMEN
Changes in global and regional precipitation regimes are among the most pervasive components of climate change. Intensification of rainfall cycles, ranging from frequent downpours to severe droughts, could cause widespread, but largely unknown, alterations to trophic structure and ecosystem function. We conducted multi-site coordinated experiments to show how variation in the quantity and evenness of rainfall modulates trophic structure in 210 natural freshwater microcosms (tank bromeliads) across Central and South America (18°N to 29°S). The biomass of smaller organisms (detritivores) was higher under more stable hydrological conditions. Conversely, the biomass of predators was highest when rainfall was uneven, resulting in top-heavy biomass pyramids. These results illustrate how extremes of precipitation, resulting in localized droughts or flooding, can erode the base of freshwater food webs, with negative implications for the stability of trophic dynamics.
Asunto(s)
Bromelia , Ecosistema , Inundaciones , Agua Dulce , Animales , Biodiversidad , Biomasa , Cambio Climático , Sequías , Cadena Alimentaria , Hidrología , América del SurRESUMEN
There is growing recognition that ecosystems may be more impacted by infrequent extreme climatic events than by changes in mean climatic conditions. This has led to calls for experiments that explore the sensitivity of ecosystems over broad ranges of climatic parameter space. However, because such response surface experiments have so far been limited in geographic and biological scope, it is not clear if differences between studies reflect geographic location or the ecosystem component considered. In this study, we manipulated rainfall entering tank bromeliads in seven sites across the Neotropics, and characterized the response of the aquatic ecosystem in terms of invertebrate functional composition, biological stocks (total invertebrate biomass, bacterial density) and ecosystem fluxes (decomposition, carbon, nitrogen). Of these response types, invertebrate functional composition was the most sensitive, even though, in some sites, the species pool had a high proportion of drought-tolerant families. Total invertebrate biomass was universally insensitive to rainfall change because of statistical averaging of divergent responses between functional groups. The response of invertebrate functional composition to rain differed between geographical locations because (1) the effect of rainfall on bromeliad hydrology differed between sites, and invertebrates directly experience hydrology not rainfall and (2) the taxonomic composition of some functional groups differed between sites, and families differed in their response to bromeliad hydrology. These findings suggest that it will be difficult to establish thresholds of "safe ecosystem functioning" when ecosystem components differ in their sensitivity to climatic variables, and such thresholds may not be broadly applicable over geographic space. In particular, ecological forecast horizons for climate change may be spatially restricted in systems where habitat properties mediate climatic impacts, and those, like the tropics, with high spatial turnover in species composition.
Asunto(s)
Cambio Climático , Ecosistema , Animales , Sequías , Invertebrados , LluviaRESUMEN
Schinus fasciculata es un árbol de la ecorregión chaqueña argentina. Es una especie de bajo porte, usada como antiséptico, analgésico, antiinflamatorio y antifúngico. Estudios previos registraron baja germinación y deficiente sanidad. El objetivo fue evaluar la germinación y la respuesta de las plántulas in vitro en dos medios de cultivo. Se recolectaron frutos, se desinfectaron por 20 min con HClNa y se sembraron en agar-agua. Las plántulas se repicaron a medio MS en dos diluciones: un cuarto (MS ») y un medio (MS ½). Se hicieron ensayos de germinación y vigor (tiempo medio de germinación máxima en días). Se evaluó % de contaminación. A los 20 días del repique se evaluó % de explantos con hojas, número de hojas y altura de plántulas. Paralelamente se hizo un ensayo de germinación y vigor en arena. La contaminación fue de 16 %, la germinación de 84 %, el vigor de 4,9 días. El 94 y el 100 % de los explantos en MS » y MS ½ presentaron hojas. El número promedio de hojas fue de 7,5 y 7,4 y la altura promedio fue de 3,35 cm y 2,98 cm en MS » y MS ½, observándose diferencias significativas en altura. La germinación en arena fue de 46 % y el vigor de 4,6 días. La utilización de la técnica de cultivo in vitro en S. fasciculata facilita la multiplicación de esta especie de alto valor farmacológico, permitiendo aumentar el porcentaje de frutos germinados y obtener plántulas libres de patógenos todo el año.
Schinus fasciculata is a tree of Argentina Chaco eco-region. It is a low-growing species, used as an antiseptic, analgesic, anti-inflammatory and antifungal. Previous studies reported low germination and poor health. The object of this work was to evaluate the germination and in vitro response of seedlings in two culture media. Fruits were collected, disinfected for 20 min with HClNa and sowing in agar - water. The seedlings were seeded onto MS medium in two dilutions: fourth (» MS) and half (½ MS). Germination and vigor tests (mean time to maximum germination in days) were made. Contamination percentage was evaluated. At 20 days of transplanted were evaluated: % of explants with leaves, leaf number and height of seedlings. Parallel assay germination and vigor in sand was made. Contamination was 16%, germination was 84% and vigor 4.9 days. The 94 % and the 100% of the explants in MS » and ½ MS showed leaves. The average leaf number was 7.5 and 7.4 and the average height was 3.35 cm and 2.98 cm in MS » and MS ½, with a significant difference in height. Germination in sand was 46 % and vigor was of 4.6 days. The technique of in vitro culture in S. fasciculata facilitates the multiplication of this species of high pharmacological value, allowing to increase the percentage of germination and obtain pathogen-free all year seedlings.
RESUMEN
Introdução: A aplicação de um substituto cutâneo adequado desempenha um papel importante na restauração dos aspectos funcionais e estéticos da pele. O padrão ouro para a cobertura de defeitos de espessura total são os enxertos autólogos. No entanto, a qualidade do tecido reconstruído e a contratura cicatricial são problemas bem conhecidos. O uso de substitutos dérmicos constitui uma abordagem alternativa na resolução desses problemas. Objetivo: O objetivo deste trabalho é avaliar o uso de MATRIDERM® em dois casos distintos conduzidos pela equipe de cirurgia plástica do Hospital de Força Aérea do Galeão (HFAG), Rio de Janeiro, Brasil. Relato dos Casos: São relatados os casos de dois pacientes, o primeiro eles apresentava sequela de queimadura em membro superior e o segundo uma ferida complexa pós trauma em terço distal de membro inferior, com exposição óssea e tendínea.
Introduction: The use of an adequate skin substitute plays an importantrole in restoring the esthetical and functional aspects of the skin. Autologous skin grafts are the gold standard for coverage of total thickness defects. However, quality of the newly built tissue and scar contracture are well known problems. The use of dermal substitutes represents an alternative in solving these problems. Objective: Thegoal of this study is to evaluate the use of MATRIDERM® in two distinct cases conducted by the plastic surgery team of Hospital de Força Aérea do Galeão (HFAG), in Rio de Janeiro, Brazil. Cases Report: The first case was a burn sequel of the upper limb, and the second one was a complex post trauma injury of the distal third of the lower limb with boneand tendinous exposure.
Asunto(s)
Humanos , Colágeno/uso terapéutico , Elastina/uso terapéutico , Quemaduras/terapia , Piel Artificial , Cicatrización de HeridasRESUMEN
Dor e trismo podem revelar-se como complicações pós-operatórias comuns advindas da cirurgia de remoção de terceiros molares inferiores. A pesquisa teve como objetivo principal avaliar o grau de abertura bucal e dor pós-operatória em pacientes submetidos à remoção de terceiros molares inferiores em uma Clínica de Cirurgia Buco-Dental de Adultos (CBDA), no Centro Especializado em Odontologia û Centro, Fortaleza, em 2004. Os dados foram coletados mediante três instrumentos de pesquisa e analisados estatisticamente. Dentre os resultados mais relevantes, destacamos a presença de vários graus de limitação de abertura de boca e dor pós-operatória. Ainda, pudemos concluir que a sintomatologia dolorosa pós-operatória tem um caráter subjetivo; contudo há necessidade de ampliarmos o estudo para este adquirir validade externa.
Asunto(s)
Humanos , Dolor Postoperatorio/etiología , Tercer Molar/cirugía , Trismo/etiologíaRESUMEN
O modelo matemático apresentado tem como objetivos: (1) simular as dinâmicas populacionais de um sistema hospedeiro parasitóide de três níveis tróficos composto pelas populações de mosca-do-mediterrâneo Ceratitis capitata (Wiedemann), vespa braconídea parasitóide Diachasmimorpha longicaudata (Ashmed) e frutos cítricos; (2) auxiliar no melhor entendimento dos principais fatores biológicos e ecológicos que regem as interações populacionais e (3) colaborar com programas mais eficientes de controle biológico para o sistema em questão. A metodologia empregada baseou-se na formulação de sistemas de equações de diferenças que descrevessem os processos de interação do sistema trófico. Posteriormente, foram elaboradas resoluções numéricas desses sistemas de equações e sua representação gráfica, utilizando-se o programa computacional Matlab, versão 6.1. Os dados biológicos e ecológicos necessários para a formulação das equações matemáticas foram fornecidos por especialistas em controle de C. capitata e retirados da literatura referente ao controle biológico das moscas-das-frutas em plantações de citros no Brasil, principalmente através da utilização de vespas parasitóides, como D. longicaudata. Os resultados obtidos nas simulações sugerem que o modelo proposto descreve adequadamente o sistema ecológico em questão e permite entender melhor suas principais características biológicas e ecológicas. Em conseqüência pode auxiliar na escolha do modo e momento para liberação da vespa parasitóide para o controle mais efetivo de C. capitata.
The mathematical model proposed has the objectives: (1) to simulate the population dynamics of a tritrophic system composed by the Mediterranean-fruit-fly Ceratitis capitata (Wiedemann), the braconid wasp Diachasmimorpha longicaudata (Ashmed) and citric fruits; (2) help to better understand the main biological and ecological factors affecting the population interactions and (3) contribute to more efficient biological control programs. The methodology was based on the formulation of different equation systems, which described the interaction processes of the trophic system. Numerical resolutions and graphical representation of these equation systems were produced, using the computational program Matlab, version 6.1. The biological and ecological data necessary to formulate the mathematical equations were provided by specialists in C. capitata control, and on the literature related to the biological control of fruit flies in citrus cultivars in Brazil, mainly with parasitoid wasps, such as D. longicaudata. The simulation results suggest that the proposed model describes suitably the ecological system considered, and permit a better comprehension of its main biological and ecological characteristics. Consequently the model may help to choose the best way and moment to liberate the parasitoid wasps aiming to a more effective control of C. capitata.