排序方式: 共有43条查询结果,搜索用时 31 毫秒
1.
Phillip J. Dugger Pedro G. Blendinger Katrin Bhning‐Gaese Lackson Chama Marta Correia D. Matthias Dehling Carine Emer Nina Farwig Evan C. Fricke Mauro Galetti Daniel García Ingo Grass Ruben Heleno Fbio A. F. Jacomassa Suelen Moraes Catherine Moran Marcia C. Muoz Eike Lena Neuschulz Larissa Nowak Augusto Piratelli Marco A. Pizo Marta Quitin Haldre S. Rogers Romn A. Ruggera Francisco Saavedra Mariano S. Snchez Rocío Snchez Vinicio Santilln Dana G. Schabo Fernanda Ribeiro da Silva Srgio Timteo Anna Traveset Maximilian G. R. Vollstdt Matthias Schleuning 《Global Ecology and Biogeography》2019,28(2):248-261
2.
Ricardo?S.?CeiaEmail author Hugo?L.?Sampaio Sandra?H.?Parejo Ruben?H.?Heleno Maria?L.?Arosa Jaime?A.?Ramos Geoff?M.?Hilton 《Biological invasions》2011,13(1):93-104
The invasive Clethra arborea has a dual-role in the diet of the Azores bullfinch, a critically endangered bird species endemic to the island of São Miguel (Azores, Portugal). This is a crucial winter food resource but it lowers the availability of native laurel forest species that compose most of the bird’s diet throughout the year. The removal of this and other invasive alien species is part of current laurel forest habitat restoration programmes, disregarding the impact on the Azores bullfinch population. In order to evaluate the first responses of the Azores bullfinch to habitat restoration, we studied bird diet, foraging behaviour, food availability and habitat occupancy in managed (without C. arborea) and control areas. Significant increases in the availability of native food resources in managed areas were noticeable in the diet, particularly the intake of Ilex perado ssp. azorica and Prunus lusitanica ssp. azorica flower buds. In most of the studied months birds heavily used and foraged in managed over control areas. The one exception was in December, when a resource-gap occurred in managed areas, which may be overcome in the short-term due to re-establishment of native plants following removal of invasive aliens. 相似文献
3.
David Monticelli Ricardo Ceia Ruben Heleno Hugo Laborda Sergio Timóteo Daniel Jare?o Geoff M. Hilton Jaime A. Ramos 《Journal of Ornithology》2010,151(3):627-636
This paper reports analyses of a capture–mark–recapture (CMR) dataset of 149 Azores Bullfinches ringed on S?o Miguel island
(Azores) between 2005 and 2007, and recaptured–resighted on a monthly basis over a 4-year period (2005–2008) throughout their
breeding range. We examined the effect of time, age (adults vs. juveniles), gender (adult males and females), and environmental
covariates (temperature, rainfall, NAO index) on survival probabilities. The modelling found a high and constant monthly survival
probability (mean ± SE) estimated at 0.96 ± 0.01, similar between both adults and juveniles and independent of environmental
conditions and gender. These findings agree with expectations from island-based life-history theory where relatively mild
conditions and lack of predators should favour high survival rates to compensate for the low reproductive output. The annual
survival rate was estimated at 0.62, which was also consistent with this pattern when compared with survival estimates of
mainland bullfinch and passerine species on other subtropical islands obtained in similar CMR studies. Based on a canonical
estimator, the size of the studied population (mean ± SE) was estimated at 1608 ± 326 individuals. Given that the population
size was only around 120–400 individuals in the early 1990s, we suggest that the high survival probabilities currently applying
to this critically endangered species may have substantially contributed to the recent recovery of this population. Future
research studies on the species’ demography should continue to monitor survival in order to measure the effect of management
interventions currently taking place within the range of the Azores Bullfinch, including the restoration of the biodiversity
rich laurel forest, but also focusing on nest success, which is important for understanding population dynamics. 相似文献
4.
5.
Camila Nassif Aline Regina Gomes Gustavo H. C. Peixoto Mauro Heleno Chagas Danusa Dias Soares Emerson Silami-Garcia Eric J. Drinkwater Jack Cannon Frank E. Marino 《PloS one》2014,9(8)
This study evaluated double blind ingestions of placebo (PLA) versus 6% carbohydrate (CHO) either as capsules (c) or beverage (b) during 60 km self-paced cycling in the heat (32°C and 50% relative humidity). Ten well-trained males (mean ± SD: 26±3 years; 64.5±7.7 kg and 70.7±8.8 ml.kg−1.min−1 maximal oxygen consumption) completed four separate 60 km time trials (TT) punctuated by 1 km sprints (14, 29, 44, 59 km) whilst ingesting either PLAb or PLAc or CHOb or CHOc. The TT was not different among treatments (PLAb 130.2±11.2 min, CHOb 140.5±18.1 min, PLAc 143.1±29.2 min, CHOc 137.3±20.1 min; P>0.05). Effect size (Cohen’s d) for time was only moderate when comparing CHOb – PLAb (d = 0.68) and PLAb – PLAc (d = 0.57) whereas all other ES were ‘trivial’ to ‘small’. Mean speed throughout the trial was significantly higher for PLAb only (P<0.05). Power output was only different (P<0.05) between the sprints and low intensity efforts within and across conditions. Core and mean skin temperatures were similar among trials. We conclude that CHO ingestion is of little or no benefit as a beverage compared with placebo during 60 km TT in the heat. 相似文献
6.
7.
Manuel Galea‐Rojas Heleno Bolfarine Mrio de Castro 《Biometrical journal. Biometrische Zeitschrift》2002,44(1):59-81
In this paper, the local influence approach for detecting the effect of small perturbations of the model or data is applied in the context of comparative calibration models. Such models are typically used for comparing several measuring instruments and can be considered in a functional version as well as in a structural version as is the case with ordinary measurement error models. Different perturbation schemes are considered and some real data applications illustrate the usefulness of the approach. 相似文献
8.
In survival studies with families or geographical units it may be of interest testing whether such groups are homogeneous for given explanatory variables. In this paper we consider score type tests for group homogeneity based on a mixing model in which the group effect is modelled as a random variable. As opposed to hazard-based frailty models, this model presents survival times that conditioned on the random effect, has an accelerated failure time representation. The test statistics requires only estimation of the conventional regression model without the random effect and does not require specifying the distribution of the random effect. The tests are derived for a Weibull regression model and in the uncensored situation, a closed form is obtained for the test statistic. A simulation study is used for comparing the power of the tests. The proposed tests are applied to real data sets with censored data. 相似文献
9.
Ruben Heleno Cristina Garcia Pedro Jordano Anna Traveset José Maria Gómez Nico Blüthgen Jane Memmott Mari Moora Jorge Cerdeira Susana Rodríguez-Echeverría Helena Freitas Jens M. Olesen 《Biology letters》2014,10(1)
In recent years, the analysis of interaction networks has grown popular as a framework to explore ecological processes and the relationships between community structure and its functioning. The field has rapidly grown from its infancy to a vibrant youth, as reflected in the variety and quality of the discussions held at the first international symposium on Ecological Networks in Coimbra—Portugal (23–25 October 2013). The meeting gathered 170 scientists from 22 countries, who presented data from a broad geographical range, and covering all stages of network analyses, from sampling strategies to effective ways of communicating results, presenting new analytical tools, incorporation of temporal and spatial dynamics, new applications and visualization tools.1 During the meeting it became evident that while many of the caveats diagnosed in early network studies are successfully being tackled, new challenges arise, attesting to the health of the discipline. 相似文献
10.
Renato L. T. Parreira Eveline S. Costa Vladimir C. G. Heleno Lizandra G. Magalhes Julia M. Souza Patrícia M. Pauletti Wilson R. Cunha Ana H. Janurio Guilherme V. Símaro Jairo K. Bastos Rosangela S. Laurentiz Tapas Kar Giovanni F. Caramori Daniel Fbio Kawano Mrcio L. AndradeeSilva 《化学与生物多样性》2019,16(1)
Six dibenzylbutyrolactonic lignans ((?)‐hinokinin ( 1 ), (?)‐cubebin ( 2 ), (?)‐yatein ( 3 ), (?)‐5‐methoxyyatein ( 4 ), dihydrocubebin ( 5 ) and dihydroclusin ( 6 )) were isolated from Piper cubeba seed extract and evaluated against Schistosoma mansoni. All lignans, except 5 , were able to separate the adult worm pairs and reduce the egg numbers during 24 h of incubation. Lignans 1 , 3 and 4 (containing a lactone ring) were the most efficient concerning antiparasitary activity. Comparing structures 3 and 4 , the presence of the methoxy group at position 5 appears to be important for this activity. Considering 1 and 3 , it is possible to see that the substitution pattern change (methylenedioxy or methoxy groups) in positions 3′ and 4′ alter the biological response, with 1 being the second most active compound. Computational calculations suggest that the activity of compound 4 can be correlated with the largest lipophilicity value. 相似文献