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AbstractIn this essay, I explore ethical considerations that might arise from the use of collaborative filtering algorithms on dating apps. Collaborative filtering algorithms can predict the preferences of a target user by looking at the past behavior of similar users. By recommending products through this process, they can influence the news we read, the movies we watch, and more. They are extremely powerful and effective on platforms like Amazon and Google. Recommender systems on dating apps are likely to group people by race, since they exhibit similar patterns of behavior: users on dating platforms seem to segregate themselves based on race, exclude certain races from romantic and sexual consideration (except their own), and generally show a preference for white men and women. As collaborative filtering algorithms learn from these patterns to predict preferences and build recommendations, they can homogenize the behavior of dating app users and exacerbate biased sexual and romantic behavior.

The use of sunscreens is an established and recommended practice to protect skin from solar-induced damage. Around 30 UV filters can be used in sunscreen products in the European Union, which ought to follow the requirements of the regulation 1223/2009 to ensure their efficacy and safety for humans. Nevertheless, low photostability and putative toxicity for humans and environment have been reported for some UV filters. Particularly, the negative impact in marine organisms has recently raised concern on the scientific community. Therefore, it is important to develop new UV filters with improved safety profile and photostability. Over the last two decades, nearly 200 new compounds have revealed promising photoprotection properties. The explored compounds were obtained through different approaches, including exploration of natural sources, synthetic pathways, and nanotechnology. Almost 50 natural products and around 140 synthetic derivatives, such as benzimidazoles, benzotriazoles, hydroxycinnamic acids, xanthones, triazines, among others, have been studied aiming the discovery of novel, effective, and safer future photoprotective agents. Herein, we provide the reader with an overview about UV filters' challenges and prospects, offering a forward-looking to the next-generation of UV filters.

8871 8876 20 8 ; S ; This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.20.008871 . Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law We present a theoretical and experimental analysis of nonlinear microwave photonic filters. Far from the conventional condition of low modulation index commonly used to neglect high-order terms, we have analyzed the harmonic distortion involved in microwave photonic structures with periodic and non-periodic frequency responses. We show that it is possible to design microwave photonic filters with reduced harmonic distortion and high linearity even under large signal operation. © 2012 Optical Society of America. The authors wish to acknowledge the financial support given by the Research Excellency Award Program GVA PROMETEO 2008/09 and the FEDER Program "Instrumentacion Avanzada para Comunicaciones Opticas" with reference UPVOV08-3E-008. Rius Mercado, M.; Mora Almerich, J.; Bolea Boluda, M.; Capmany Francoy, J. (2012). Harmonic distortion in microwave photonic filters. Optics Express. 20(8):8871-8876. doi:10.1364/OE.20.008871 Capmany, J., & Novak, D. (2007). Microwave photonics combines two worlds. Nature Photonics, 1(6), 319-330. doi:10.1038/nphoton.2007.89 Yao, J. (2009). Microwave Photonics. Journal of Lightwave Technology, 27(3), 314-335. doi:10.1109/jlt.2008.2009551 Capmany, J., Ortega, B., & Pastor, D. (2006). A tutorial on microwave photonic filters. Journal of Lightwave Technology, 24(1), 201-229. doi:10.1109/jlt.2005.860478 Minasian, R. A., Alameh, K. E., & Chan, E. H. W. (2001). Photonics-based interference mitigation filters. IEEE Transactions on Microwave Theory and Techniques, 49(10), 1894-1899. doi:10.1109/22.954804 Bolea, M., Mora, J., Ortega, B., & Capmany, J. (2010). Photonic arbitrary ...

ABSTRACTA recently developed nitrification model for biological filters has been applied to the design of three sites to increase nitrification. The first site was upgraded by the installation of a dedicated recirculation facility, the second by reconfiguration to double filtration, and the third by the installation of a chemical pre‐precipitation plant. All three sites responded well to the modifications and achieved compliance with ammoniacal nitrogen consents of 3–5 mg/l on a 95%oile basis. The key influence of hydraulic load on nitrification capacity and reliability was demonstrated on all three plants. The ability to upgrade existing biological filter installations to meet stringent ammoniacal nitrogen consents allows a significant reduction in environmental impact and revenue costs when compared with energy‐intensive options such as the activated‐sludge process.

ABSTRACTA high microbiological quality of drinking water must be ensured to protect public health. The filtration techniques that are used in treating drinking water play an important role; however, a biofilm can form on granular‐media filters and the accumulated bacteria can slough off and enter the filtered water.The aim of this research was to examine (a) the potential for biofilm formation and detachment from filter sand, and (b) the effect of different backwash regimes on biofilm removal. During the operation of the filter, bacteria became attached to the sand media, particularly in the top 30 mm of the filter bed. A water‐only backwash at 20% and 40% bed expansion demonstrated poor removal of biofilm throughout the depth of the bed. Collapse‐pulsing is a more efficient method and results in a reduction in the number of bacteria in the filtered water.