Bird Community Responses to Rest-Rotation Grazing in Western Canada\u27s Grasslands

Western Canada’s native grasslands support high levels of avian diversity including both resident and migrant species. Many grassland specialist bird populations, however, are in serious decline due to widespread habitat loss resulting from agricultural conversion and adverse land management. As the primary use on remaining grasslands, cattle grazing largely determines the availability and quality of bird species’ habitat, depending on the timing, intensity, and frequency of livestock use. While adaptive multi-paddock grazing (AMP, a short duration, high-intensity grazing system that prioritises plant recovery between grazing events) is growing in popularity, comprehensive assessments of bird diversity in relation to AMP grazing practices are largely lacking. As part of a larger grazing management study, we examined how AMP grazing practices influence the taxonomic and phylogenetic diversity of bird species, compared to neighbouring (n-AMP) properties managed with more conventional grazing practices. In addition to the AMP/n-AMP contrast, we used rancher survey information to test for the influence of specific grazing practices over and above biophysical effects. Bird communities were surveyed at 309 point count locations across 38 ranches (set up as matched pairs) using visual and acoustic detection. Overall, we identified 96 bird species, of which 81 species were recorded on AMP-grazed ranches compared to 84 species on grasslands under n-AMP grazing, ranging from 10-32 species per ranch. We observed a considerable grazing management signal on species abundance and diversity including significant associations between some threatened species and n-AMP grazing. Moreover, AMP grazing, and specifically the use of higher rest-to-grazing ratios early in the growing season (prior to August 1), was associated with phylogenetically more clustered bird communities. Overall, this study highlights the potential of specialized rotational grazing systems to alter the composition and phylogenetic diversity of grassland bird communities. In conclusion, we stress the importance for prioritisation of strategic management plans to safeguard and restore North America’s grassland bird communities

Laser Wire Scanner Development on CTF II

A laser wire scanner is under development at CERN in the framework of the Compact Linear Collider study (CLIC). A first test has been carried out at the CLIC Test Facility II (CTF II) with the aim of developing a beam profile monitor for a low energy, high charge electron beam. In our set-up a 2.5 mJ, 1047 nm, 4 ps laser pulse interacts with a 50 MeV, 1 nC, 4 ps electron bunch. A scintillator detects up to 600 X-ray photons, with an average energy of 17 keV. In the present status of the experiment Thomson photons have been observed, but the signal to noise ratio is however still too low for an accurate profile measurement

imageseg: An R package for deep learning-based image segmentation

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2022 The Authors. Methods in Ecology and Evolution published by John Wiley & Sons Ltd on behalf of British Ecological SocietyConvolutional neural networks (CNNs) and deep learning are powerful and robust tools for ecological applications and are particularly suited for image data. Image segmentation (the classification of all pixels in images) is one such application and can, for example, be used to assess forest structural metrics. While CNN-based image segmentation methods for such applications have been suggested, widespread adoption in ecological research has been slow, likely due to technical difficulties in implementation of CNNs and lack of toolboxes for ecologists. Here, we present R package imageseg which implements a CNN-based workflow for general purpose image segmentation using the U-Net and U-Net++ architectures in R. The workflow covers data (pre)processing, model training and predictions. We illustrate the utility of the package with image recognition models for two forest structural metrics: tree canopy density and understorey vegetation density. We trained the models using large and diverse training datasets from a variety of forest types and biomes, consisting of 2877 canopy images (both canopy cover and hemispherical canopy closure photographs) and 1285 understorey vegetation images. Overall segmentation accuracy of the models was high with a Dice score of 0.91 for the canopy model and 0.89 for the understorey vegetation model (assessed with 821 and 367 images respectively). The image segmentation models performed significantly better than commonly used thresholding methods and generalized well to data from study areas not included in training. This indicates robustness to variation in input images and good generalization strength across forest types and biomes. The package and its workflow allow simple yet powerful assessments of forest structural metrics using pretrained models. Furthermore, the package facilitates custom image segmentation with single or multiple classes and based on colour or grayscale images, for example, for applications in cell biology or for medical images. Our package is free, open source and available from CRAN. It will enable easier and faster implementation of deep learning-based image segmentation within R for ecological applications and beyond.publishedVersio

Time resolved spectrometry on the CLIC Test Facility 3

The high charge (>6ìC) electron beam produced in the CLIC Test Facility 3 (CTF3) is accelerated in fully beam loaded cavities. To be able to measure the resulting strong transient effects, the time evolution of the beam energy and its energy spread must be determined with at least 50MHz bandwidth. Three spectrometer lines are installed along the linac in order to control and tune the beam. The electrons are deflected by dipole magnets onto Optical Transition Radiation (OTR) screens which are observed by CCD cameras. The measured horizontal beam size is then directly related to the energy spread. In order to provide time-resolved energy spectra, a fraction of the OTR photons is sent onto a multi-channel photomultiplier. The overall setup is described, special focus is given to the design of the OTR screen with its synchrotron radiation shielding. The performance of the time-resolved measurements are discussed in detail. Finally, the limitations of the system, mainly due to radiation problems are discussed

Beam Dynamics and First Operation of the Sub-Harmonic Bunching System in the CTF3 Injector

The CLIC Test Facility 3 (CTF3), built at CERN by an international collaboration, aims at demonstrating the feasibility of the CLIC scheme by 2010. The CTF3 drive beam generation scheme relies on the use of a fast phase switch of a sub-harmonic bunching system in order to phase-code the bunches. The amount of charge in unwanted satellite bunches is an important quantity, which must be minimized. Beam dynamic simulations have been used to study the problem, showing the limitation of the present CTF3 design and the gain of potential upgrades. In this paper the results are discussed and compared with beam measurements taken during the first operation of the system

Discussion on Research and Development of Local Documents Exchange Platform

地方文献是一个地方政治、经济、文化和社会事业发展以及历史、风俗、资源等方面的文献资料.它具有区域性、史料性、广泛性和时代性等特点，地方文献与一般文献的最主要区别在于其具有地方特色。因此，它是目前国内外图书馆界公认的重要文献资源之一。但是由于各地方图书馆在地方文献的收集标准、范围上并没有达成共识，收集重点也不明确。在地方文献保管上，除少数图书馆是设专库集中收藏外，绝大多数馆是分散在各个书库之中；在数据库建设方面缺乏统筹规划，处于一种无序的、各自为政的状态。因此，必须加强地方文献信息资源共享建设，使之更好的促进社会的发展，而传统的地方文献资源共享的方式主要有：建立联合目录与进行合作编目、馆际互借、...Local documents are a local political, economic, cultural and social undertakings development and the history, customs, resources and other aspects of documents. It has the characteristics of regional, historical data, universality and times. The most important differences between local documents and general documents is that local documents has its local characteristics. Therefore, it is one of t...学位：工学硕士院系专业：图书馆_计算机技术学号：X200822102

High Power test of a low group velocity X-band Accelerator Structure for CLIC

In recent years evidence has been found that the maximum sustainable gradient in an accelerating structure depends on the rf power flow through the structure. The CLIC study group has consequently designed a new prototype structure for CLIC with a very low group velocity, input power and average aperture ( = 0.13). The 18 cell structure has a group velocity of 2.6 % at the entrance and 1 % at the last cell. Several of these structures have been made in a collaboration between KEK, SLAC and CERN. A total of five brazed-disk structures and two quadrant structures have been made. The high power results of the first KEK/SLAC built structure is presented which reached an unloaded gradient in excess of 100 MV/m at a pulse length of 230 ns with a breakdown rate below 10-6 per meter active length. The high-power testing was done using the NLCTA facility at SLAC

A High-Gradient Test of a 30 GHz Molybdenum-Iris Structure

The CLIC study is actively investigating a number of different materials in an effort to find ways to increase achievable accelerating gradient. So far a series of rf tests have been made with a set of identical-geometry structures: a W-iris 30 GHz structure, a Mo-iris 30 GHz structure (with pulses as long as 16 ns) and a scaled Mo-iris X-band structure. A second Mo-iris 30 GHz structure of the same geometry has now been tested in CTF3 with pulse lengths up to 350 ns. The structure was conditioned to a gradient of 140 MV/m with a 70 ns pulse length and a breakdown rate slope of 13 MV/m per decade has been measure