35 research outputs found
Serviços ecológicos de insetos e outros artrópodes em sistemas agroflorestais.
Com a crescente demanda global por alimentos hĂĄ aumento do impacto ambiental das atividades para produção animal e agrĂcola sobre a biodiversidade, ocasionando redução cada vez mais acentuada de insetos e artĂłprodes. PorĂ©m, os serviços ecolĂłgicos fornecidos pela biodiversidade podem ser importantes para a produção sustentĂĄvel de alimentos em sistemas agroflorestais. Nessa revisĂŁo bibliogrĂĄfica objetivou-se elucidar como insetos e artrĂłpodes podem ser benĂ©ficos em sistemas de produção agropecuĂĄrios, em especial sistemas agroflorestais (SAFs). A diversidade desses organismos auxilia na conservação e preservação do meio ambiente dentro e no entorno desse tipo de uso da terra. AlĂ©m disso, pesquisas cientĂficas constataram que o nicho ecolĂłgico de insetos e outros tipos de artrĂłpodes sĂŁo essencialmente importantes para a ciclagem de nutrientes e manutenção da sustentabilidade e produção dos agroecossistemas. As monoculturas, quando comparadas com sistemas agroflorestais, provocam significativas perdas de biodiversidade, inclusive de insetos. Portanto, a exploração de sistemas agroflorestais em consonĂąncia com a preservação do meio ambiente e aproveitando seus serviços ecolĂłgicos pode ser uma alternativa sutentĂĄvel para ĂĄreas de produção agrĂcola
Femtosecond dark-field imaging with an X-ray free electron laser
The emergence of femtosecond diffractive imaging with X-ray lasers has enabled pioneering structural studies of isolated particles, such as viruses, at nanometer length scales. However, the issue of missing low frequency data significantly limits the potential of X-ray lasers to reveal sub-nanometer details of micrometer-sized samples. We have developed a new technique of dark-field coherent diffractive imaging to simultaneously overcome the missing data issue and enable us to harness the unique contrast mechanisms available in dark-field microscopy. Images of airborne particulate matter (soot) up to two microns in length were obtained using single-shot diffraction patterns obtained at the Linac Coherent Light Source, four times the size of objects previously imaged in similar experiments. This technique opens the door to femtosecond diffractive imaging of a wide range of micrometer-sized materials that exhibit irreproducible complexity down to the nanoscale, including airborne particulate matter, small cells, bacteria and gold-labeled biological samples. (C) 2012 Optical Society of Americ
Noise-robust coherent diffractive imaging with a single diffraction pattern
The resolution of single-shot coherent diffractive imaging at X-ray free-electron laser facilities is limited by the low signal-to-noise level of diffraction data at high scattering angles. The iterative reconstruction methods, which phase a continuous diffraction pattern to produce an image, must be able to extract information from these weak signals to obtain the best quality images. Here we show how to modify iterative reconstruction methods to improve tolerance to noise. The method is demonstrated with the hybrid input-output method on both simulated data and single-shot diffraction patterns taken at the Linac Coherent Light Source. (C) 2012 Optical Society of Americ
Tunability experiments at the FERMI@Elettra free-electron laser
FERMI@Elettra is a free electron-laser (FEL)-based user facility that, after two years of commissioning, started preliminary users' dedicated runs in 2011. At variance with other FEL user facilities, FERMI@Elettra has been designed to deliver improved spectral stability and longitudinal coherence. The adopted scheme, which uses an external laser to initiate the FEL process, has been demonstrated to be capable of generating FEL pulses close to the Fourier transform limit. We report on the first instance of FEL wavelength tuning, both in a narrow and in a large spectral range (fine- and coarse-tuning). We also report on two different experiments that have been performed exploiting such FEL tuning. We used fine-tuning to scan across the 1sâ4p resonance in He atoms, at â23.74 eV (52.2 nm), detecting both UVâvisible fluorescence (4pâ2s, 400 nm) and EUV fluorescence (4pâ1s, 52.2 nm). We used coarse-tuning to scan the M4,5 absorption edge of Ge (âŒ29.5 eV) in the wavelength region 30â60 nm, measured in transmission geometry with a thermopile positioned on the rear side of a Ge thin foil
International Veterinary Epilepsy Task Force consensus proposal: Medical treatment of canine epilepsy in Europe
In Europe, the number of antiepileptic drugs (AEDs) licensed for dogs has grown considerably over the last years. Nevertheless, the same questions remain, which include, 1) when to start treatment, 2) which drug is best used initially, 3) which adjunctive AED can be advised if treatment with the initial drug is unsatisfactory, and 4) when treatment changes should be considered. In this consensus proposal, an overview is given on the aim of AED treatment, when to start long-term treatment in canine epilepsy and which veterinary AEDs are currently in use for dogs. The consensus proposal for drug treatment protocols, 1) is based on current published evidence-based literature, 2) considers the current legal framework of the cascade regulation for the prescription of veterinary drugs in Europe, and 3) reflects the authorsâ experience. With this paper it is aimed to provide a consensus for the management of canine idiopathic epilepsy. Furthermore, for the management of structural epilepsy AEDs are inevitable in addition to treating the underlying cause, if possible
Amazonia Camtrap: a data set of mammal, bird, and reptile species recorded with camera traps in the Amazon forest.
Abstract : The Amazon forest has the highest biodiversity on Earth. However, information on Amazonian vertebrate diversity is still deficient and scatteredacross the published, peer-reviewed, and gray literature and in unpublishedraw data. Camera traps are an effective non-invasive method of surveying vertebrates, applicable to different scales of time and space. In this study, we organized and standardized camera trap records from different Amazonregions to compile the most extensive data set of inventories of mammal,bird, and reptile species ever assembled for the area. The complete data setcomprises 154,123 records of 317 species (185 birds, 119 mammals, and13 reptiles) gathered from surveys from the Amazonian portion of eightcountries (Brazil, Bolivia, Colombia, Ecuador, French Guiana, Peru,Suriname, and Venezuela). The most frequently recorded species per taxawere: mammals:Cuniculus paca (11,907 records); birds: Pauxi tuberosa (3713 records); and reptiles:Tupinambis teguixin(716 records). The infor-mation detailed in this data paper opens up opportunities for new ecological studies at different spatial and temporal scales, allowing for a moreaccurate evaluation of the effects of habitat loss, fragmentation, climatechange, and other human-mediated defaunation processes in one of themost important and threatened tropical environments in the world. The data set is not copyright restricted; please cite this data paper when usingits data in publications and we also request that researchers and educator sinform us of how they are using these data
Ultrafast Dynamics of Magnetic Domain Structures Probed by Coherent Free-Electron Laser Light
The free-electron laser (FEL) sources FLASH in Hamburg, LCLS at Stanford, and FERMI in Trieste provide XUV to soft X-ray radiation (FLASH and FERMI) or soft to hard X-ray radiation (LCLS) with unprecedented parameters in terms of ultrashort pulse length, high photon flux, and coherence. These properties make FELs ideal tools for studying ultrafast dynamics in matter on a previously unaccessible level. This paper first reviews results obtained at FEL sources during the last few years in the field of magnetism research. We start with pioneering experiments at FLASH demonstrating the feasibility of magnetic scattering at FELs [1, 2], then present pumpâprobe scattering experiments [3, 4] as well as the first FEL magnetic imaging experiments [5], and finally discuss a limitation of the scattering methods due to a quenching of the magnetic scattering signal by high-fluence FEL pulses [6]. All of the presented experiments exploit the X-ray magnetic circular dichroism effect [7, 8] to obtain element-specific magnetic scattering contrast, as known from synchrotron experiments [9â12]
Profiling structured beams using injected aerosols
Profiling structured beams produced by X-ray free-electron lasers (FELs) is crucial to both maximizing signal intensity for weakly scattering targets and interpreting their scattering patterns. Earlier ablative imprint studies describe how to infer the X-ray beam profile from the damage that an attenuated beam inflicts on a substrate. However, the beams in-situ profile is not directly accessible with imprint studies because the damage profile could be different from the actual beam profile. On the other hand, although a Shack-Hartmann sensor is capable of in-situ profiling, its lenses may be quickly damaged at the intense focus of hard X-ray FEL beams. We describe a new approach that probes the in-situ morphology of the intense FEL focus. By studying the translations in diffraction patterns from an ensemble of randomly injected sub-micron latex spheres, we were able to determine the non-Gaussian nature of the intense FEL beam at the Linac Coherent Light Source (SLAC National Laboratory) near the FEL focus. We discuss an experimental application of such a beam-profiling technique, and the limitations we need to overcome before it can be widely applied