Image Recognition of Breast Tumor Proliferation Level Based on Convolution Neural Network

Pathological slide is increasingly applied in the diagnosis of breast tumors despite the issues of large amount of data, slow viewing and high subjectivity. To overcome these problems, a micrograph recognition method based on convolutional neural network is proposed for pathological slide of breast tumor. Combined with multi-channel threshold and watershed segmentation, a sample database including single cell, adhesive cell and invalid cell was established. Then, the convolution neural network with six layers is constructed, which has ability to classify the stained breast tumor cells with accuracy of more than 90%, and evaluate the proliferation level with relative error of less than 5%. The experimental result indicates the effectiveness of this approach, and is useful for providing an objective basis for evaluating the malignancy of breast tumors.     

Feeding range of age 1+ year Eurasian perch Perca fluviatilis in the Baltic Sea

Using the widespread Eurasian perch Perca fluviatilis as a model organism, feeding ranges were investigated using stable‐isotope ratios (δ¹⁵N and δ¹³C) and body condition. Differences were found between closely located sampling sites in a littoral area without obvious migration barriers, indicating that individual fish had small feeding ranges. Body condition differences between sampled stations were consistent over 4 years. Such sedentary behaviour is important to consider in, e.g. fisheries management and environmental monitoring, as local catch regulations may be meaningful or geographic stability in sampling locations may reduce noise in data.     

Regional and temporal variation in diet and provisioning rates suggest weather limits prey availability for an endangered raptor

Understanding variation in food requirements of wild animals is of central importance in population ecology and conservation, as it helps to identify where and when food may be limiting. Studies on diet variation or prey provisioning rates may give useful insights when direct information on prey availability is lacking. We assess spatial and temporal variation in the diet of an endangered predator, the Black Harrier Circus maurus. This raptor is endemic to southern Africa and specializes on small mammals but also feeds on birds and reptiles as alternative prey. Using data on 1679 prey identified in 953 pellets collected in inland and coastal regions from 2006 to 2015, we show that diet composition changed little throughout the breeding season in the coastal region, whereas there was a marked seasonal decline in the occurrence of small mammal prey in the inland region, with a concomitant increase in alternative prey. The proportion of small mammals in the diet declined with increasing maximum temperature, the latter being highest at the inland region late in the breeding season. Using camera recordings at nests in 2014, we further analysed daily patterns of prey provisioning to nestlings. A marked reduction in small mammal provisioning rates occurred during the middle of the day in the hotter inland region but not in the cooler coastal region. Reduced availability of the primary prey, small mammals, in hotter conditions, through a reduction in activity or overall abundance, could explain these patterns. Finally, we show a positive relationship between winter rainfall and interannual differences in the proportion of small mammals in the diet of Black Harriers breeding in the coastal region, suggesting relationships between diet and prey abundance that are mediated through rainfall. We discuss the need to consider spatial variation in food availability in conservation strategies.     

Macrophyte beds in a subtropical reservoir shifted from a nutrient sink to a source after drying then rewetting

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Do upstream migrating,juvenile amphidromous shrimps,provide a marine subsidy to river ecosystems?

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Omnivory and stability in freshwater habitats: Does theory match reality?

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Improved Performance of Ternary Polymer Solar Cells Based on A Nonfullerene Electron Cascade Acceptor

Efficient ternary polymer solar cells are constructed by incorporating an electron‐deficient chromophore (5Z,5′Z)‐5,5′‐((7,7′‐(4,4,9,9‐tetrakis(4‐hexylphenyl)‐4,9‐dihydro‐s‐indaceno[1,2‐b:5,6‐b′]dithiophene‐2,7‐diyl)bis(6‐fluorobenzo[c][1,2,5]thiadiazole‐7,4‐diyl))bis(methanylylidene))bis(3‐ethyl‐2‐thioxothiazolidin‐4‐one) (IFBR) as an additional component into the bulk‐heterojunction film that consists of a wide‐bandgap conjugated benzodithiophene‐alt‐difluorobenzo[1,2,3]triazole based copolymer and a fullerene acceptor. With respect to the binary blend films, the incorporation of a certain amount of IFBR leads to simultaneously enhanced absorption coefficient, obviously extended absorption band, and improved open‐circuit voltage. Of particular interest is that devices based on ternary blend film exhibit much higher short‐circuit current densities than the binary counterparts, which can be attributed to the extended absorption profiles, enhanced absorption coefficient, favorable film morphology, as well as formation of cascade energy level alignment that is favorable for charge transfer. Further investigation indicates that the ternary blend device exhibits much shorter charge carrier extraction time, obviously reduced trap density and suppressed trap‐assisted recombination, which is favorable for achieving high short‐circuit current. The combination of these beneficial aspects leads to a significantly improved power conversion efficiency of 8.11% for the ternary device, which is much higher than those obtained from the binary counterparts. These findings demonstrate that IFBR can be a promising electron‐accepting material for the construction of ternary blend films toward high‐performance polymer solar cells.