Improving hyperspectral band selection by constructing an estimated reference map

We investigate band selection for hyperspectral image classification. Mutual information (MI) measures the statistical dependence between two random variables. By modeling the reference map as one of the two random variables, MI can, therefore, be used to select the bands that are more useful for image classification. A new method is proposed to estimate the MI using an optimally constructed reference map, reducing reliance on ground-truth information. To reduce the interferences from noise and clutters, the reference map is constructed by averaging a subset of spectral bands that are chosen with the best capability to approximate the ground truth. To automatically find these bands, we develop a searching strategy consisting of differentiable MI, gradient ascending algorithm, and random-start optimization. Experiments on AVIRIS 92AV3C dataset and Pavia University scene dataset show that the proposed method outperformed the benchmark methods. In AVIRIS 92AV3C dataset, up to 55% of bands can be removed without significant loss of classification accuracy, compared to the 40% from that using the reference map accompanied with the dataset. Meanwhile, its performance is much more robust to accuracy degradation when bands are cut off beyond 60%, revealing a better agreement in the MI calculation. In Pavia University scene dataset, using 45 bands achieved 86.18% classification accuracy, which is only 1.5% lower than that using all the 103 bands

Effects of ceftiofur sodium liposomes on free radical formation in mice

To examine the effects of ceftiofur sodium liposomes on the free radical formation in liver of mice, 24 mice were assigned randomly into three groups, i.e., 1) ceftiofur sodium; 2) ceftiofur sodium liposomes and 3) physiological saline. Treatments were applied via intraperitoneal injections for 7 days. At the end of the treatment period, animals were euthanized and liver collected for analysis of superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents and the ability of liver tissue to suppress hydroxyl radical formation. Ceftiofur sodium liposomes-treated mice had higher activity of SOD than ceftiofur sodium- and saline-treated mice; however, MDA content and the ability of liver tissue to suppress hydroxyl radical formation did not reach statistical significance among groups. It was concluded that ceftiofur sodium liposomes can improve the SOD activity compared to ceftiofur alone in mice

Initial fixation placement in face images is driven by top-down guidance

The eyes are often inspected first and for longer period during face exploration. To examine whether this saliency of the eye region at the early stage of face inspection is attributed to its local structure properties or to the knowledge of its essence in facial communication, in this study we investigated the pattern of eye movements produced by rhesus monkeys (Macaca mulatta) as they free viewed images of monkey faces. Eye positions were recorded accurately using implanted eye coils, while images of original faces, faces with scrambled eyes, and scrambled faces except for the eyes were presented on a computer screen. The eye region in the scrambled faces attracted the same proportion of viewing time and fixations as it did in the original faces, even the scrambled eyes attracted substantial proportion of viewing time and fixations. Furthermore, the monkeys often made the first saccade towards to the location of the eyes regardless of image content. Our results suggest that the initial fixation placement in faces is driven predominantly by ‘top-down’ or internal factors, such as the prior knowledge of the location of “eyes” within the context of a face

Effects of exogenous spermidine on photosynthesis, xanthophyll cycle and endogenous polyamines in cucumber seedlings exposed to salinity

The effects of exogenous spermidine (Spd, 1 mmol·L-1) on photosynthetic characteristics, xanthophylls cycle components and endogenous polyamines levels were investigated in cucumber seedlings subjected to salt stress (75 mmol·L-1 NaCl). Chlorophyll contents and net photosynthetic rate (PN) of cucumber seedlings showed a significant decrease under salinity but an increase with exogenous Spd application. Salt stress caused a remarkable decline in the maximum quantum efficiency (Fv/Fm) and the actual efficiency of photosystem II (ФPSⅡ), where an increase was observed in the constitutive loss processes (ΦNO). Application of exogenous Spd significantly decreased ФNO and enhanced regulated non-photochemical energy loss (ФNPQ) in the salt-stressed plants. Spd treatment caused an increase in the size of xanthophyll cycle pool (VAZ) and further enhanced de-epoxidation of the xanthophyll cycle (DEPS) under salt stress. These results suggest that exogenous Spd alleviated salt-mediated decline in photosynthetic efficiency through the enhanced involvement of the energy dissipation that is dependent on the xanthophyll cycle. In addition, foliar spray Spd significantly increased the free, bound and conjugated polyamines in the leaves of the salt stressed plants. Spd also increased the free putrescine (Put)/(Spd+Spm) ratio and decreased bound and conjugated Put/(Spd+Spm) under salinity. Thus, we conclude that Spd can alleviate salt-induced damage on cucumber seedlings by regulating the levels of endogenous polyamines, which was associated with an improvement in the photochemical efficiency of PSII of the salt stressed plants.Key words: Cucumber, endogenous polyamines, photosynthetic characteristics, salt stress, spermidine

On the Application of Strong Magnetic Fields during Organic Crystal Growth

We investigate the effect of crystal growth within a magnetic field for three polymorphic pharmaceuticals, using an experiment where the magnetic field can be varied in strength without altering other crystallization conditions. In the case of carbamazepine, fields above 0.6 T produce metastable form I, and for flufenamic acid, there is an increased propensity to crystallize metastable form I around 1 T. In contrast, the magnetic field has no effect on the crystallization of mefenamic acid, a closely related molecule. The growth of the metastable β polymorph of coronene within a magnetic field at ambient temperature is difficult to reproduce but has been seen as a minor component, consistent with this transformation to the more stable form being facile, depending on the particle size. Calculations of the diamagnetic susceptibility tensors of the polymorphs and their morphologies provide semiquantitative estimates of how the diamagnetic susceptibilities of crystallites differ between polymorphs and explain why mefenamic acid crystallization is unaffected. As the onset of crystallization of carbamazepine and coronene, as defined by changes in turbidity, occur at lower temperatures and hence greater supersaturations in certain ranges of magnetic field strength, this suggests that the field causes precipitation of the metastable form through Ostwald’s rule of stages

Comparative Evaluation of Action Recognition Methods via Riemannian Manifolds, Fisher Vectors and GMMs: Ideal and Challenging Conditions

We present a comparative evaluation of various techniques for action recognition while keeping as many variables as possible controlled. We employ two categories of Riemannian manifolds: symmetric positive definite matrices and linear subspaces. For both categories we use their corresponding nearest neighbour classifiers, kernels, and recent kernelised sparse representations. We compare against traditional action recognition techniques based on Gaussian mixture models and Fisher vectors (FVs). We evaluate these action recognition techniques under ideal conditions, as well as their sensitivity in more challenging conditions (variations in scale and translation). Despite recent advancements for handling manifolds, manifold based techniques obtain the lowest performance and their kernel representations are more unstable in the presence of challenging conditions. The FV approach obtains the highest accuracy under ideal conditions. Moreover, FV best deals with moderate scale and translation changes

Confirmation of low genetic diversity and multiple breeding females in a social group of Eurasian badgers from microsatellite and field data

The Eurasian badger ( Meles meles ) is a facultatively social carnivore that shows only rudimentary co-operative behaviour and a poorly defined social hierarchy. Behavioural evidence and limited genetic data have suggested that more than one female may breed in a social group. We combine pregnancy detection by ultrasound and microsatellite locus scores from a well-studied badger population from Wytham Woods, Oxfordshire, UK, to demonstrate that multiple females reproduce within a social group. We found that at least three of seven potential mothers reproduced in a group that contained 11 reproductive age females and nine offspring. Twelve primers showed variability across the species range and only five of these were variable in Wytham. The microsatellites showed a reduced repeat number, a significantly higher number of nonperfect repeats, and moderate heterozygosity levels in Wytham. The high frequency of imperfect repeats and demographic phenomena might be responsible for the reduced levels of variability observed in the badger

Berkovich Nanoindentation on AlN Thin Films

Berkovich nanoindentation-induced mechanical deformation mechanisms of AlN thin films have been investigated by using atomic force microscopy (AFM) and cross-sectional transmission electron microscopy (XTEM) techniques. AlN thin films are deposited on the metal-organic chemical-vapor deposition (MOCVD) derived Si-doped (2 × 1017 cm−3) GaN template by using the helicon sputtering system. The XTEM samples were prepared by means of focused ion beam (FIB) milling to accurately position the cross-section of the nanoindented area. The hardness and Young’s modulus of AlN thin films were measured by a Berkovich nanoindenter operated with the continuous contact stiffness measurements (CSM) option. The obtained values of the hardness and Young’s modulus are 22 and 332 GPa, respectively. The XTEM images taken in the vicinity regions just underneath the indenter tip revealed that the multiple “pop-ins” observed in the load–displacement curve during loading are due primarily to the activities of dislocation nucleation and propagation. The absence of discontinuities in the unloading segments of load–displacement curve suggests that no pressure-induced phase transition was involved. Results obtained in this study may also have technological implications for estimating possible mechanical damages induced by the fabrication processes of making the AlN-based devices

Inversion of provenance data and sediment load into spatially varying erosion rates

Sediment fingerprinting methods aim to determine the relative contribution of different source areas in detrital sediments based on natural properties – fingerprints – of the source areas. Here, we use U/Th–Pb age signatures as fingerprints, assuming that the age signal is not altered during erosion–transportation–deposition events, and given that recent technological advances enable precise dating of large amounts of grains. We introduce a formal inversion method that allows to disentangle the amalgamation of source contributions in detrital zircon data and enables to convert this information into an erosion rate map starting from the spatial distribution of zircon age signatures. Relying on the least‐squares method and using prior and covariance information to deal with non‐uniqueness, we show, using synthetic and natural examples, that we are able to retrieve erosion rate patterns of a catchment when the age distribution and zircon fertility for each source area are well known. Moreover, we show that not only zircon age fingerprints but also other tracers such as mineral content can be used. Furthermore, we found that adding data from samples taken at the outlet of tributaries improves the estimation of erosion rate patterns. We conclude that the least squares inverse model applied to detrital data has great potential for investigating erosion rates

Color Differences Highlight Concomitant Polymorphism of Chalcones

The meta- and para-nitro isomers of (E)-3′-dimethylamino-nitrochalcone (Gm8m and Gm8p) are shown to exhibit concomitant color polymorphism, with Gm8m appearing as yellow (P2_{1}/c) or orange (P1̅) crystals and Gm8p appearing as red (P2_{1}/n) or black (P2_{1}/c) crystals. Each of the polymorphs was characterized optically via UV–vis spectroscopy, and their thermal behavior was characterized via differential scanning calorimetry and low-temperature powder X-ray diffraction. To assess the effect of molecular configuration and crystal packing on the colors of crystals of the different polymorphs, time dependent density functional theory (ωB97x) calculations were carried out on isolated molecules, dimers, stacks, and small clusters cut from the crystal structures of the four polymorphs. The calculated color comes from several excitations and is affected by conformation and most intermolecular contacts within the crystal, with the color differences between polymorphs mainly being due to the differences in the π–π stacking. The visual differences between these related polymorphic systems make them particularly useful for studying polymorph behavior such as phase transitions and concomitant polymorph growth