Photonic integrated reconfigurable linear processors as neural network accelerators

Reconfigurable linear optical processors can be used to perform linear transformations and are instrumental in effectively computing matrix–vector multiplications required in each neural network layer. In this paper, we characterize and compare two thermally tuned photonic integrated processors realized in silicon-on-insulator and silicon nitride platforms suited for extracting feature maps in convolutional neural networks. The reduction in bit resolution when crossing the processor is mainly due to optical losses, in the range 2.3–3.3 for the silicon-on-insulator chip and in the range 1.3–2.4 for the silicon nitride chip. However, the lower extinction ratio of Mach–Zehnder elements in the latter platform limits their expressivity (i.e., the capacity to implement any transformation) to 75%, compared to 97% of the former. Finally, the silicon-on-insulator processor outperforms the silicon nitride one in terms of footprint and energy efficiency

A Horizon Scan of research priorities to inform policies aimed at reducing the harm of plastic pollution to biota

Plastic pollution in the oceans is a priority environmental issue. The recent increase in research on the topic, coupled with growing public awareness, has catalyzed policymakers around the world to identify and implement solutions that minimize the harm caused by plastic pollution. To aid and coordinate these efforts, we surveyed experts with scientific experience identified through their peer-reviewed publications. We asked experts about the most pressing research questions relating to how biota interact with plastic pollution that in turn can inform policy decisions and research agendas to best contribute to understanding and reducing the harm of plastic pollution to biota. We used a modified Horizon Scan method that first used a subgroup of experts to generate 46 research questions on aquatic biota and plastics, and then conducted an online survey of researchers globally to prioritize questions in terms of their importance to inform policy development. One hundred and fifteen experts from 29 countries ranked research questions in six themes. The questions were ranked by urgency, indicating which research should be addressed immediately, which can be addressed later, and which are of limited relevance to inform action on plastics as an environmental pollutant. We found that questions relating to the following four themes were the most commonly top-ranked research priorities: (i) sources, circulation and distribution of plastics, (ii) type of harm from plastics, (iii) detection of ingested plastics and the associated problems, and (iv) related economies and policy to ingested plastics. While there are many research questions on the topic of impacts of plastic pollution on biota that could be funded and investigated, our results focus collective priorities in terms of research that experts believe will inform effective policy and on-the-ground conservation.© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/

Bidirectional Transmission in an Optical Network on Chip With Bus and Ring Topologies

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Albumin and mammalian cell culture: implications for biotechnology applications

Albumin has a long historical involvement in design of media for the successful culture of mammalian cells, in both the research and commercial fields. The potential application of albumins, bovine or human serum albumin, for cell culture is a by-product of the physico-chemical, biochemical and cell-specific properties of the molecule. In this review an analysis of these features of albumin leads to a consideration of the extracellular and intracellular actions of the molecule, and importantly the role of its interactions with numerous ligands or bioactive factors that influence the growth of cells in culture: these include hormones, growth factors, lipids, amino acids, metal ions, reactive oxygen and nitrogen species to name a few. The interaction of albumin with the cell in relation to these co-factors has a potential impact on metabolic and biosynthetic activity, cell proliferation and survival. Application of this knowledge to improve the performance in manufacturing biotechnology and in the emerging uses of cell culture for tissue engineering and stem cell derived therapies is an important prospect

Surface water plastics in the Eastern Arctic

This study finds an average of 0.018 plastic particles/m2 in surface waters near the capital city of Iqaluit in Tasiujarjuaq (Frobisher Bay), Nunavut (0.014 particles/m2), and in the Labrador Sea close to Qaqortoq and Narsaq in southwest Greenland (0.026 particles/m2). While a comparison with other studies shows the abundance of plastics in the study area holds with a broad increase in plastic abundance in the north compared to the south, within and across study areas, latitude does not appear to be a significant factor in plastic abundance. Moreover, some characteristics of recovered plastics such as morphology and colour support local origins, while others support long range transport. Research moving forward should consider relative scales in spatial trends of plastic abundance. Samples for this study were collected in 2018 by a team of settler, non-Inuit authors using a Manta surface water trawl with a net mesh size of 335μm, and each trawl was conducted for 30 minutes. The cut off size for this data set is 425μm. Sample collection sites were designed to answer two specific questions. First, whether burned plastics that might have originated in the Iqaluit landfill were moving from land into Tasiujarjuaq, a local hypothesis. Sampling locations in Tasiujarjuaq are grouped close to Iqaluit and further in the bay to test that hypothesis. Secondly, the site in southwest Greenland was used as a comparison to determine whether the abundance and types of plastics in Tasiujarjuaq (both near Iqaluit and farther into the bay) were markedly different than those of a location in another current but at a similar latitude. This sample collection design this provides a snapshot of plastic profiles in key locations, and is limited to wider generalizations given its relatively low sample size (see the section below on statistical power), and that samples were collected in the late summer months rather than across multiple seasons. This data was used for the publication: "Abundance and types of plastic pollution in surface waters in the Eastern Arctic (Inuit Nunangat) and the case for reconciliation science" (2021). More information about the data is available there, and/or by contacting Max Liboiron [email protected]

Surface water plastics in the Eastern Arctic

This study finds an average of 0.018 plastic particles/m2 in surface waters near the capital city of Iqaluit in Tasiujarjuaq (Frobisher Bay), Nunavut (0.014 particles/m2), and in the Labrador Sea close to Qaqortoq and Narsaq in southwest Greenland (0.026 particles/m2). While a comparison with other studies shows the abundance of plastics in the study area holds with a broad increase in plastic abundance in the north compared to the south, within and across study areas, latitude does not appear to be a significant factor in plastic abundance. Moreover, some characteristics of recovered plastics such as morphology and colour support local origins, while others support long range transport. Research moving forward should consider relative scales in spatial trends of plastic abundance. Samples for this study were collected in 2018 by a team of settler, non-Inuit authors using a Manta surface water trawl with a net mesh size of 335μm, and each trawl was conducted for 30 minutes. The cut off size for this data set is 425μm. Sample collection sites were designed to answer two specific questions. First, whether burned plastics that might have originated in the Iqaluit landfill were moving from land into Tasiujarjuaq, a local hypothesis. Sampling locations in Tasiujarjuaq are grouped close to Iqaluit and further in the bay to test that hypothesis. Secondly, the site in southwest Greenland was used as a comparison to determine whether the abundance and types of plastics in Tasiujarjuaq (both near Iqaluit and farther into the bay) were markedly different than those of a location in another current but at a similar latitude. This sample collection design this provides a snapshot of plastic profiles in key locations, and is limited to wider generalizations given its relatively low sample size (see the section below on statistical power), and that samples were collected in the late summer months rather than across multiple seasons. This data was used for the publication: "Abundance and types of plastic pollution in surface waters in the Eastern Arctic (Inuit Nunangat) and the case for reconciliation science" (2021). More information about the data is available there, and/or by contacting Max Liboiron [email protected]