Doodle to Search: Practical Zero-Shot Sketch-based Image Retrieval

In this paper, we investigate the problem of zero-shot sketch-based image retrieval (ZS-SBIR), where human sketches are used as queries to conduct retrieval of photos from unseen categories. We importantly advance prior arts by proposing a novel ZS-SBIR scenario that represents a firm step forward in its practical application. The new setting uniquely recognizes two important yet often neglected challenges of practical ZS-SBIR, (i) the large domain gap between amateur sketch and photo, and (ii) the necessity for moving towards large-scale retrieval. We first contribute to the community a novel ZS-SBIR dataset, QuickDraw-Extended, that consists of 330,000 sketches and 204,000 photos spanning across 110 categories. Highly abstract amateur human sketches are purposefully sourced to maximize the domain gap, instead of ones included in existing datasets that can often be semi-photorealistic. We then formulate a ZS-SBIR framework to jointly model sketches and photos into a common embedding space. A novel strategy to mine the mutual information among domains is specifically engineered to alleviate the domain gap. External semantic knowledge is further embedded to aid semantic transfer. We show that, rather surprisingly, retrieval performance significantly outperforms that of state-of-the-art on existing datasets that can already be achieved using a reduced version of our model. We further demonstrate the superior performance of our full model by comparing with a number of alternatives on the newly proposed dataset. The new dataset, plus all training and testing code of our model, will be publicly released to facilitate future researchComment: Oral paper in CVPR 201

Why the general Zakharov-Shabat equations form a hierarchy?

The totality of all Zakharov-Shabat equations (ZS), i.e., zero-curvature equations with rational dependence on a spectral parameter, if properly defined, can be considered as a hierarchy. The latter means a collection of commuting vector fields in the same phase space. Further properties of the hierarchy are discussed, such as additional symmetries, an analogue to the string equation, a Grassmannian related to the ZS hierarchy, and a Grassmannian definition of soliton solutions.Comment: 13p

Evaluation of African oil palm germplasm for drought tolerance

A field experiment was conducted at ARS Campus, Gangavati, University of Horticultural Sciences, Bagalkot to evaluate the oil palm genotypes for drought tolerance under medium black soils of Tungabhadra Command area of Karnataka. Nine oil palm genotypes were collected from Zambia and Tanzania for drought tolerance studies under rainfed conditions. The genotype ZS-3 recorded significantly higher fresh fruit bunch (FFB) yield 7.0 t ha-1 over Z-6, ZS-8, ZS-8, ZS-9, TS-5 and TS-7. Number of bunches were significantly higher in the genotypes ZS-3 (4.4) followed by ZS-1 (4.1) and ZS-9 (4.0). Bunch weight was significantly higher in the genotype ZS-3 (11.2 kg bunch-1) followed by ZS-5 (10.8 kg bunch-1) and ZS-6 (9.4 kg bunch-1). The number of fruits per bunch was significantly higher in the genotype ZS-8 (3031) over all other genotypes. The number of male inflorescence was lower with the genotype ZS-5 and TS-5 (7.8 and 8.0 respectively). The number of female inflorescence was higher with the genotypes ZS-3 and TS-5 (7.0 and 7.0, respectively). Per cent sex ratio was higher with the genotype TS-5 and ZS-5 (46.2 and 44.8, respectively). The genotype ZS-1 and ZS-5 recorded higher annual leaf production of 21.4 and 20.3, respectively. The genotype ZS-1 recorded significantly lower number of leaf scorched per palm of 2.2 over other genotypes but it was on par with genotype ZS-3 (3.6). The data on various physiological and biochemical parameters revealed that the genotype ZS-1 and ZS-3 recorded higher relative water content, lower electrolyte leaching and significantly lower peroxidase activity indicating relatively more stress tolerant than other tested genotypes

Is the Number of Giant Arcs in LCDM Consistent With Observations?

We use high-resolution N-body simulations to study the galaxy-cluster cross-sections and the abundance of giant arcs in the $\Lambda$CDM model. Clusters are selected from the simulations using the friends-of-friends method, and their cross-sections for forming giant arcs are analyzed. The background sources are assumed to follow a uniform ellipticity distribution from 0 to 0.5 and to have an area identical to a circular source with diameter 1\arcsec. We find that the optical depth scales as the source redshift approximately as \tau_{1''} = 2.25 \times 10^{-6}/[1+(\zs/3.14)^{-3.42}] (0.6<\zs<7). The amplitude is about 50% higher for an effective source diameter of 0.5\arcsec. The optimal lens redshift for giant arcs with the length-to-width ratio ($L/W$) larger than 10 increases from 0.3 for \zs=1, to 0.5 for \zs=2, and to 0.7-0.8 for \zs>3. The optical depth is sensitive to the source redshift, in qualitative agreement with Wambsganss et al. (2004). However, our overall optical depth appears to be only $\sim$ 10% to 70% of those from previous studies. The differences can be mostly explained by different power spectrum normalizations ($\sigma_8$) used and different ways of determining the $L/W$ ratio. Finite source size and ellipticity have modest effects on the optical depth. We also found that the number of highly magnified (with magnification $|\mu|>10$) and ``undistorted'' images (with $L/W<3$) is comparable to the number of giant arcs with $|\mu|>10$ and $L/W>10$. We conclude that our predicted rate of giant arcs may be lower than the observed rate, although the precise `discrepancy' is still unclear due to uncertainties both in theory and observations.Comment: Revised version after the referee's reports (32 pages,13figures). The paper has been significantly revised with many additions. The new version includes more detailed comparisons with previous studies, including the effects of source size and ellipticity. New discussions about the redshift distribution of lensing clusters and the width of giant arcs have been adde

Hepatoprotective, nephroprotective, anti-amylase, and antiglucosidase effects of Ziziphus spina-christi (L.) against carbon tetrachloride-induced toxicity in rats

Purpose: To explore the hepatoprotective, nephroprotective, anti-amylase, and anti-glucosidase effects of the medicinal plant Ziziphus spina-christi (L.). Methods: Ziziphus spina-christi (L.) methanol extract (ZS-1) and its ethyl-acetate (ZS-2), n-butanol (ZS3), and aqueous (ZS-4) fractions were evaluated for their hepatoprotective, anti-amylase, and antiglucosidase activities. Adult male Wister rats were divided into 11 groups (I- XI) with 6 mice per group. Group I was normal control, while the treatment groups were as follows: group II, CCl4; group III, Silymarin + CCl4; group IV, Ziziphus spina-christi total methanol extract (ZS-1), 100 mg/kg) + CCl4; group V, ZS-1 (200 mg/kg) + CCl4; group VI, ethyl acetate fraction (ZS-2), 100 mg/kg + CCl4; group VII: ZS-2 (200 mg/kg) + CCl4; group VIII, butanol fraction (ZS-3), 100 mg/kg) + CCl4; group IX, ZS-3 (200 mg/kg) + CCl4; group X, aqueous fraction (ZS-4), 100 mg/kg) + CCl4; group XI: ZS-4 (200 mg/kg) + CCl4. Silymarin was used as the standard. Biomarkers of liver and kidney toxicity and histopathological changes were evaluated. Results: Liver and kidney malondialdehyde (MDA), non-protein sulfhydryls (NP-SH) and total protein levels were elevated in CCl4-treated rats; however, ZS-1 and ZS-4 of Z. spina-christi significantly reduced these levels. ZS-2 and ZS-3 did not significantly improve the studied parameters. These results were confirmed by results from histopathological examination. ZS-1 and ZS-2 showed mild inhibitory activities against α-amylase and α-glucosidase (54 and 43 % at 100 µg/ml, respectively). Conclusion: The results indicate that ZS-1 and ZS-4 samples displayed dose-dependent hepatoprotective and nephroprotective effects, whereas ZS-2 and ZS-3 samples did not exhibit these effects. Similarly, α-amylase and α-glucosidase enzymes are considerably inhibited by ZS-1 and ZS-2