Grad-CAM++: Improved Visual Explanations for Deep Convolutional Networks

Over the last decade, Convolutional Neural Network (CNN) models have been highly successful in solving complex vision problems. However, these deep models are perceived as "black box" methods considering the lack of understanding of their internal functioning. There has been a significant recent interest in developing explainable deep learning models, and this paper is an effort in this direction. Building on a recently proposed method called Grad-CAM, we propose a generalized method called Grad-CAM++ that can provide better visual explanations of CNN model predictions, in terms of better object localization as well as explaining occurrences of multiple object instances in a single image, when compared to state-of-the-art. We provide a mathematical derivation for the proposed method, which uses a weighted combination of the positive partial derivatives of the last convolutional layer feature maps with respect to a specific class score as weights to generate a visual explanation for the corresponding class label. Our extensive experiments and evaluations, both subjective and objective, on standard datasets showed that Grad-CAM++ provides promising human-interpretable visual explanations for a given CNN architecture across multiple tasks including classification, image caption generation and 3D action recognition; as well as in new settings such as knowledge distillation.Comment: 17 Pages, 15 Figures, 11 Tables. Accepted in the proceedings of IEEE Winter Conf. on Applications of Computer Vision (WACV2018). Extended version is under review at IEEE Transactions on Pattern Analysis and Machine Intelligenc

Bacillus thuringiensis Cry11Ba works synergistically with Cry4Aa but not with Cry11Aa for toxicity against mosquito Culex pipiens (Diptera: Culicidae) larvae

A 2,175-bp modified gene (cry11Ba-S1) encoding Cry11Ba from Bacillus thuringiensis subsp. jegathesan was designed and the recombinant protein was expressed as a fusion protein with glutathione S-transferase in Escherichia coli. The recombinant Cry11Ba was highly toxic against Culex pipiens mosquito larvae, being nine and 17 times more toxic than mosquitocidal Cry4Aa and Cry11Aa from Bacillus thuringiensis subsp. israelensis, respectively. Interestingly, a further increase in the toxicity of the recombinant Cry11Ba was achieved by mixing with Cry4Aa, but not with Cry11Aa. These findings suggested that Cry11Ba worked synergistically with Cry4Aa, but not with Cry11Aa, in exhibiting toxicity against C. pipiens larvae. On the other hand, the amount of Cry toxin bound to brush border membrane vesicles (BBMVs) did not significantly change between individual toxins and the toxin mixtures, suggesting that the increase in toxins binding to BBMVs was not a reason for the observed synergistic effect. It is generally accepted that synergism of toxins is a potentially powerful tool for enhancing insecticidal activity and managing Cry toxin resistance in mosquitoes. The mixture of Cry4Aa and Cry11Ba in order to increase toxicity would be very valuable in terms of mosquito control

Hypoglycemic, hypolippidemic and antioxidant effects of leaves methanolic extract of Baccaurea ramiflora

The present study was designed for investigating the hypoglycemic, hypolipidemic and antioxidant activity of the leaves of B. ramiflora. Antioxidant potential was assayed by measuring the free radical scavenging activity using 1, 1-diphenyl-2-picrylhydrazyl (DPPH). Diabetes was induced in adult albino rats of both sexes by intra peritoneal (i.p) injection of alloxan (120 mg/kg). Methanolic extract of B. ramiflora leaves (200 mg/kg) was administered as a single dose per day to the diabetic rats for 14 days. The control group received distilled water for the same duration. Blood glucose levels and serum lipid profiles were measured in the diabetic and non-diabetic rats. The methanolic extract showed potent free radical scavenging activity with IC value of 23.83 (μg/ml). It produced substantial hypoglycemia and reduced the elevated blood glucose level in the diabetic rats towards normal and it was statistically highly significant (

Gas-Phase Synthesis of Triphenylene (C18 H12 ).

For the last decades, the hydrogen-abstraction-acetylene-addition (HACA) mechanism has been widely invoked to rationalize the high-temperature synthesis of PAHs as detected in carbonaceous meteorites (CM) and proposed to exist in the interstellar medium (ISM). By unravelling the chemistry of the 9-phenanthrenyl radical ([C14 H9 ]. ) with vinylacetylene (C4 H4 ), we present the first compelling evidence of a barrier-less pathway leading to a prototype tetracyclic PAH - triphenylene (C18 H12 ) - via an unconventional hydrogen abstraction-vinylacetylene addition (HAVA) mechanism operational at temperatures as low as 10 K. The barrier-less, exoergic nature of the reaction reveals HAVA as a versatile reaction mechanism that may drive molecular mass growth processes to PAHs and even two-dimensional, graphene-type nanostructures in cold environments in deep space thus leading to a better understanding of the carbon chemistry in our universe through the untangling of elementary reactions on the most fundamental level

Reactivity of the Indenyl Radical (C9 H7 ) with Acetylene (C2 H2 ) and Vinylacetylene (C4 H4 ).

The reactions of the indenyl radicals with acetylene (C2 H2 ) and vinylacetylene (C4 H4 ) is studied in a hot chemical reactor coupled to synchrotron based vacuum ultraviolet ionization mass spectrometry. These experimental results are combined with theory to reveal that the resonantly stabilized and thermodynamically most stable 1-indenyl radical (C9 H7 . ) is always formed in the pyrolysis of 1-, 2-, 6-, and 7-bromoindenes at 1500 K. The 1-indenyl radical reacts with acetylene yielding 1-ethynylindene plus atomic hydrogen, rather than adding a second acetylene molecule and leading to ring closure and formation of fluorene as observed in other reaction mechanisms such as the hydrogen abstraction acetylene addition or hydrogen abstraction vinylacetylene addition pathways. While this reaction mechanism is analogous to the bimolecular reaction between the phenyl radical (C6 H5 . ) and acetylene forming phenylacetylene (C6 H5 CCH), the 1-indenyl+acetylene→1-ethynylindene+hydrogen reaction is highly endoergic (114 kJ mol-1 ) and slow, contrary to the exoergic (-38 kJ mol-1 ) and faster phenyl+acetylene→phenylacetylene+hydrogen reaction. In a similar manner, no ring closure leading to fluorene formation was observed in the reaction of 1-indenyl radical with vinylacetylene. These experimental results are explained through rate constant calculations based on theoretically derived potential energy surfaces

Evaluation of the leaves of Ipomoea aquatica for its hypoglycemic and antioxidant activity

The present study was accomplished to explore the hypoglycemic and antioxidant activity of methanolic extracts of the leaves of I.aquatica. The animals used to test the antidiabetic activity were Swiss albino mice of 7-8 weeks, average weight 20-30 gm of both male and female sexes. Twenty four mice were randomly grouped into four where there were two drug groups, one control and one standard control group. Metformin was used as standard in the testing of hypoglycemic activity. Different doses as 200 mg/mg and 400 mg/kg body weight of extract were used during the course of study. Both of the doses showed potent hypoglycemic activity in comparison with the control (