Paying Positive to Go Negative: Advertisers' Competition and Media Reports

This paper analyzes a two-sided market for news where advertisers may pay a media outlet to conceal negative information about the quality of their own product (paying positive to avoid negative) and/or to disclose negative information about the quality of their competitors' products (paying positive to go negative). We show that whether advertisers have negative consequences on the accuracy of news reports or not ultimately depends on the extent of correlation among advertisers' products. Specifically, the lower the correlation among the qualities of the advertisers' products, the (weakly) higher the accuracy of the media outlet' reports. Moreover, when advertisers' products are correlated, a higher degree of competition in the market of the advertisers' products may decrease the accuracy of the media outlet's reports.

The witching week of herding on bitcoin exchanges

This paper analyses the herding behaviour among exchanges around the expiration of bitcoin futures traded on the Chicago Mercantile Exchange (CME). The database extends from December 2017 to October 2020, taking as a reference the main exchanges that trade bitcoin (Binance, Bitfinex, Bitstamp, Coinbase, itBit, Kraken, and Gemini) and using hourly closing prices and trading volumes in bitcoin and US dollars. Adapting the proposal of Chang, Cheng and Khorana (2000) (CCK) to test conditional herding, we obtain results that indicate that the herding effect is significant during the week before expiration. After expiration, the herding effect lasts for a few hours and disappears. Information overload originating, among other causes, from sophisticated investors’ strategies may generate this mimetic behaviour. The results show the relevance of intraday data applied to specific events such as expiration since the unconditional analysis shows, in general, anti-herding behaviour throughout the period of study

Is there an expiration effect in the bitcoin market?

This paper studies the monthly expiration effect in the bitcoin markets. The emergence of trading in bitcoin futures in regulated markets is an ideal occasion to test this effect on an asset with singular characteristics. Our results with intraday data show that around the time of maturity there are significant changes in the trading volume, volatility and return of bitcoin, an asset that is traded in many exchanges simultaneously. Therefore, there is a clear expiration effect related to bitcoin futures. The closer to the expiration time (shortly beforehand or afterwards), the more intense these effects are. However, in spite of these general results, the expiration effect is not homogeneous across exchanges and depends on the characteristics of the futures contract in question. Robustness tests are also applied to confirm the results. The increasing participation of institutional investors is consistent with our findings, particularly in relation to the expiration effects of cash-settled futures, as these contracts are more appealing for sophisticated investors who could be interested in arbitrage or speculative processes

Semisimple types for p -adic classical groups

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Appropriate counseling approach to disclose HIV status to HIV-infected children: Chiradzulu, Malawi

Mexico AIDS Conference 200

Estimation of the mechanical properties of the eye through the study of its vibrational modes

Measuring the eye's mechanical properties in vivo and with minimally invasive techniques can be the key for individualized solutions to a number of eye pathologies. The development of such techniques largely relies on a computational modelling of the eyeball and, it optimally requires the synergic interplay between experimentation and numerical simulation. In Astrophysics and Geophysics the remote measurement of structural properties of the systems of their realm is performed on the basis of (helio-)seismic techniques. As a biomechanical system, the eyeball possesses normal vibrational modes encompassing rich information about its structure and mechanical properties. However, the integral analysis of the eyeball vibrational modes has not been performed yet. Here we develop a new finite difference method to compute both the spheroidal and, specially, the toroidal eigenfrequencies of the human eye. Using this numerical model, we show that the vibrational eigenfrequencies of the human eye fall in the interval 100 Hz - 10 MHz. We find that compressible vibrational modes may release a trace on high frequency changes of the intraocular pressure, while incompressible normal modes could be registered analyzing the scattering pattern that the motions of the vitreous humour leave on the retina. Existing contact lenses with embebed devices operating at high sampling frequency could be used to register the microfluctuations of the eyeball shape we obtain. We advance that an inverse problem to obtain the mechanical properties of a given eye (e.g., Young's modulus, Poisson ratio) measuring its normal frequencies is doable. These measurements can be done using non-invasive techniques, opening very interesting perspectives to estimate the mechanical properties of eyes in vivo. Future research might relate various ocular pathologies with anomalies in measured vibrational frequencies of the eye.Comment: Published in PLoS ONE as Open Access Research Article. 17 pages, 5 color figure

Redworm (Eisenia fetida) as largemouth bass feed - first results

Redworm (Eisenia fetida) have been found to be a very good source of protein and fat. Chemical composition are important factor in selecting redworms as aquaculture feed but the high moisture (80.97% ±0.438) and ash (8.78% ±0.149) content, mainly soil, could be an inconvenient. On September 23, 2014 twenty two juvenile largemouth bass (LB) (Micropterus salmoides) (0+ years) were caught from a small irrigation dam (N 39º49’27,89’’; W 07º26’57,92’’). Juveniles LB were stocked in three aquarium for commercial compound feed training. After 3 weeks 86.4% are well trained. During the compound feed training period the survival rate was 100%. On October 13, 2014 sixteen feed-trained individuals were randomly selected and stocked in two aquarium (8 LB per aquaria with 0,048m3 of water). LB initial average weight, average length, average K condition factor and density were similar in two aquarium. In aquaria G1 (feed redworm) and aquaria G2 (feed commercial compound) LB weight, length, K condition factor and density were, respectively, 13.62g (±3.171) and 13.40g (±3.002) (P>0.05); 10.49cm (±0.757) and 10.39cm (±0.649) (P>0.05); 1.160 (±0.043) and 1.179 (±0.082) (P>0.05); 2,27kg/m3 and 2.23kg/m3). In our laboratorial experiment, aquarium average water temperature range between 19.9ºC and 16.8ºC. Because in Portugal there are no specific commercial feed for largemouth bass we used a commercial compound for seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) (protein 47.7%M; fat 17.3%; ash 10.9%; crude fiber 0.83%; moisture 6.1%). On day 88 (January 9, 2015) of this study average weight, length, K condition factor and density in aquaria G1 and aquaria G2 were, respectively, 17.57g (±4.071) and 19.19g (±4.811) (P0.05); 2.93kg/m3 and 3.20kg/m3). Until now E. fetida seems to be a good feed for largemouth bass

A Survey of Wearable Biometric Recognition Systems

The growing popularity of wearable devices is leading to new ways to interact with the environment, with other smart devices, and with other people. Wearables equipped with an array of sensors are able to capture the owner’s physiological and behavioural traits, thus are well suited for biometric authentication to control other devices or access digital services. However, wearable biometrics have substantial differences from traditional biometrics for computer systems, such as fingerprints, eye features, or voice. In this article, we discuss these differences and analyse how researchers are approaching the wearable biometrics field. We review and provide a categorization of wearable sensors useful for capturing biometric signals. We analyse the computational cost of the different signal processing techniques, an important practical factor in constrained devices such as wearables. Finally, we review and classify the most recent proposals in the field of wearable biometrics in terms of the structure of the biometric system proposed, their experimental setup, and their results. We also present a critique of experimental issues such as evaluation and feasibility aspects, and offer some final thoughts on research directions that need attention in future work