Online Cashback Pricing: A New Affiliate Strategy for E-Business

This paper examines the impact of “cashback” mechanism on online merchants’ affiliate and pricing strategies. Through reimbursing a portion of the transactional amount to consumers in a form of cashback, merchants are able to practice second-degree price discrimination. We develop an analytical framework which explicitly considers the cost associated with the underlying promotional vehicle. We first identify the conditions under which affiliate strategy is profitable. Surprisingly, the promotional “low” price could be actually “high”, relative to the uniform price when cashback is absent. We also propose channel coordination as a remedy to mitigate market inefficiency caused by double marginalization. Finally, we extend our model to a duopoly setting and find that a merchant can benefit from its rival’s move into the cashback market. Interestingly, under certain conditions both merchants have no incentive to move alone but prefer its rival to do so

Quantifying Social Influence in an Online Music Community

This paper studies two types of social influence in an online music community: observational learning influence based on aggregate consumption data, and social network influence based on music consumption by friends in social proximity. The analysis uses a variety of empirical methods, applied to highly granular user listening and “favoriting” behavior on the largest music blog aggregator site. Our analysis finds positive evidence for observational learning effects, but no evidence for social network influence. Thus, any social influence in this music context is channeled through popularity cues offered by aggregate consumption statistics, rather than contact and communication with friends in close social proximity. We discuss implications of these results for research and practice

Zero-norm states and stringy symmetries

We identify spacetime symmetry charges of 26D open bosonic string theory from an infinite number of zero-norm states (ZNS) with arbitrary high spin in the old covariant first quantized string spectrum. We give various evidences to support this identification. These include massive sigma-model calculation, Witten string field theory calculation, 2D string theory calculation and, most importantly, three methods of high-energy stringy scattering amplitude calculations. The last calculations explicitly prove Gross's conjectures in 1988 on high energy symmetry of string theory.Comment: 6 pages. Talks presented by Jen-Chi Lee at XXVIII Spanish Relativity Meeting (ERE2005),"A Century of Relativity Physics",Oviedo,Spain,6-10 Sep 2005 and "4th Meeting on constrained Dynamics and Quantum Gravity",Cala Gonone,Sardinia,Italy,12-16 Sep 2005. To appear in the Journal of Physics: Conference Serie

A Novel Confidence Induced Class Activation Mapping for MRI Brain Tumor Segmentation

Magnetic resonance imaging (MRI) is a commonly used technique for brain tumor segmentation, which is critical for evaluating patients and planning treatment. To make the labeling process less laborious and dependent on expertise, weakly-supervised semantic segmentation (WSSS) methods using class activation mapping (CAM) have been proposed. However, current CAM-based WSSS methods generate the object localization map using internal neural network information, such as gradient or trainable parameters, which can lead to suboptimal solutions. To address these issues, we propose the confidence-induced CAM (Cfd-CAM), which calculates the weight of each feature map by using the confidence of the target class. Our experiments on two brain tumor datasets show that Cfd-CAM outperforms existing state-of-the-art methods under the same level of supervision. Overall, our proposed Cfd-CAM approach improves the accuracy of brain tumor segmentation and may provide valuable insights for developing better WSSS methods for other medical imaging tasks

Conditional Diffusion Models for Weakly Supervised Medical Image Segmentation

Recent advances in denoising diffusion probabilistic models have shown great success in image synthesis tasks. While there are already works exploring the potential of this powerful tool in image semantic segmentation, its application in weakly supervised semantic segmentation (WSSS) remains relatively under-explored. Observing that conditional diffusion models (CDM) is capable of generating images subject to specific distributions, in this work, we utilize category-aware semantic information underlied in CDM to get the prediction mask of the target object with only image-level annotations. More specifically, we locate the desired class by approximating the derivative of the output of CDM w.r.t the input condition. Our method is different from previous diffusion model methods with guidance from an external classifier, which accumulates noises in the background during the reconstruction process. Our method outperforms state-of-the-art CAM and diffusion model methods on two public medical image segmentation datasets, which demonstrates that CDM is a promising tool in WSSS. Also, experiment shows our method is more time-efficient than existing diffusion model methods, making it practical for wider applications

Senile cataracts and oxidative stress

AbstractIn numerous epidemiological and animal models, it can be inferred that oxidative stress is a key factor in cataract formation. Production of reactive oxygen species and reduction of endogenous antioxidants both contribute to cataract formation. In the cataractogenous process, lens proteins lose sulfhydryl groups and become thiolated or cross-linked by disulfide bonds. The resultant high molecular weight aggregates become insoluble and affect lens transparency. All these are consequences of changes in the redox state. A mixed protein-thiol and protein-protein disulfide bond precedes the morphological changes of cataract. Normally, sustained high levels of reduced glutathione provide a protective effect, while depletion of glutathione causes damage to epithelial cells and fiber cells. UV rays in the ambient environment evoke reactive oxygen species formation and also contribute to cataracts. The reduction in free UV filters and increase in their binding to lens proteins make the lens more predisposed to UV damage and oxidation. In the aqueous humor of cataract lenses, there is a decrease in antioxidant enzymes and increase in nitric oxide, which demonstrates the relationship between oxidative stress and cataracts. Though surgical intervention is the standard treatment for cataracts, experimental medical therapies for cataracts are under extensive investigation. Carnosine, a pro-drug of carnosine-N-acetylcarnosine, bendazac, ascorbic acid, and aldose reductase inhibitors are under therapeutic evaluation, and prevention of cataract formation may be possible in the future

High-energy zero-norm states and symmetries of string theory

High-energy limit of zero-norm states (HZNS) in the old covariant first quantized (OCFQ) spectrum of the 26D open bosonic string, together with the assumption of a smooth behavior of string theory in this limit, are used to derive infinitely many linear relations among the leading high-energy, fixed angle behavior of four point functions of different string states. As a result, ratios among all high-energy scattering amplitudes of four arbitrary string states can be calculated algebraically and the leading order amplitudes can be expressed in terms of that of four tachyons as conjectured by Gross in 1988. A dual calculation can also be performed and equivalent results are obtained by taking the high-energy limit of Virasoro constraints. Finally, as a consistent sample calculation, we compute all high-energy scattering amplitudes of three tachyons and one massive state at the leading order by saddle-point approximation to justify our results.Comment: 10 pages, no figure, modifications of text and reference

Exposure to Secondhand Smoke and Risk of Tuberculosis: Prospective Cohort Study

Background: Prospective evidence on the association between secondhand-smoke exposure and tuberculosis is limited. Methods: We included 23,827 never smokers from two rounds (2001 and 2005) of Taiwan National Health Interview Survey. Information on exposure to secondhand smoke at home as well as other sociodemographic and behavioral factors was collected through in-person interview. The participants were prospectively followed for incidence of tuberculosis through cross-matching the survey database to the national tuberculosis registry of Taiwan. Results: A total of 85 cases of active tuberculosis were identified after a median follow-up of 7.0 years. The prevalence of exposure to secondhand smoke at home was 41.8% in the study population. In the multivariable Cox proportional hazards analysis, secondhand smoke was not associated with active tuberculosis (adjusted hazard ratio [HR], 1.03; 95% CI, 0.64 to 1.64). In the subgroup analysis, the association between secondhand smoke and tuberculosis decreased with increasing age; the adjusted HR for those = 18 and = 40 and = 60 years old was 8.48 (0.77 to 93.56), 2.29 (0.75 to 7.01), 1.33 (0.58 to 3.01), and 0.66 (0.35 to 1.23) respectively. Results from extensive sensitivity analyses suggested that potential misclassification of secondhand-smoke exposure would not substantially affect the observed associations. Conclusions: The results from this prospective cohort study did not support an overall association between secondhand smoke and tuberculosis. However, the finding that adolescents might be particularly susceptible to secondhand smoke's effect warrants further investigation

High expression FUT1 and B3GALT5 is an independent predictor of postoperative recurrence and survival in hepatocellular carcinoma.

Cancer may arise from dedifferentiation of mature cells or maturation-arrested stem cells. Previously we reported that definitive endoderm from which liver was derived, expressed Globo H, SSEA-3 and SSEA-4. In this study, we examined the expression of their biosynthetic enzymes, FUT1, FUT2, B3GALT5 and ST3GAL2, in 135 hepatocellular carcinoma (HCC) tissues by qRT-PCR. High expression of either FUT1 or B3GALT5 was significantly associated with advanced stages and poor outcome. Kaplan Meier survival analysis showed significantly shorter relapse-free survival (RFS) for those with high expression of either FUT1 or B3GALT5 (P = 0.024 and 0.001, respectively) and shorter overall survival (OS) for those with high expression of B3GALT5 (P = 0.017). Combination of FUT1 and B3GALT5 revealed that high expression of both genes had poorer RFS and OS than the others (P < 0.001). Moreover, multivariable Cox regression analysis identified the combination of B3GALT5 and FUT1 as an independent predictor for RFS (HR: 2.370, 95% CI: 1.505-3.731, P < 0.001) and OS (HR: 2.153, 95% CI: 1.188-3.902, P = 0.012) in HCC. In addition, the presence of Globo H, SSEA-3 and SSEA-4 in some HCC tissues and their absence in normal liver was established by immunohistochemistry staining and mass spectrometric analysis