The Coral Protein CARP3 Acts from a Disordered Mineral Surface Film to Divert Aragonite Crystallization in Favor of Mg‐Calcite

Stony corals construct their aragonite skeleton by calcium carbonate precipitation, in a process recently suggested to be biologically controlled. Amorphous calcium carbonate and small amounts of calcite are also reported recently, however, their functional role is unknown. Coral acid‐rich proteins (CARPs) are extracted from the coral skeleton and are shown to be active in calcium carbonate precipitation in vitro. However, individual function of these proteins in coral mineralization is not known. Here, the regulatory activity of the aspartate‐rich CARP3 protein is examined. The whole protein and two peptides representing its acidic domain and its variable domain are used in CaCO₃ precipitation reactions from Mg‐rich solutions. The biomolecules alter crystallization pathways, promoting Mg‐calcite in place of aragonite, with the acidic peptide capable of eradicating aragonite formation. The activity of CARP3 and its representative peptides is exerted from disordered CaCO₃ mineral phases, coating the crystals formed, as shown by 2D ¹H–¹³C heteronuclear correlation nuclear magnetic resonance (NMR) measurements, localizing organic protons in atomic proximity to disordered carbonate carbons. The structures of the protein and individual domains as derived from NMR measurements and folding calculations and their amino acid compositions are discussed in the context of their observed activity and its implication to mineralization in hard corals.     

CoralSeg: Learning coral segmentation from sparse annotations

Robotic advances and developments in sensors and acquisition systems facilitate the collection of survey data in remote and challenging scenarios. Semantic segmentation, which attempts to provide per‐pixel semantic labels, is an essential task when processing such data. Recent advances in deep learning approaches have boosted this task's performance. Unfortunately, these methods need large amounts of labeled data, which is usually a challenge in many domains. In many environmental monitoring instances, such as the coral reef example studied here, data labeling demands expert knowledge and is costly. Therefore, many data sets often present scarce and sparse image annotations or remain untouched in image libraries. This study proposes and validates an effective approach for learning semantic segmentation models from sparsely labeled data. Based on augmenting sparse annotations with the proposed adaptive superpixel segmentation propagation, we obtain similar results as if training with dense annotations, significantly reducing the labeling effort. We perform an in‐depth analysis of our labeling augmentation method as well as of different neural network architectures and loss functions for semantic segmentation. We demonstrate the effectiveness of our approach on publicly available data sets of different real domains, with the emphasis on underwater scenarios—specifically, coral reef semantic segmentation. We release new labeled data as well as an encoder trained on half a million coral reef images, which is shown to facilitate the generalization to new coral scenarios.     

The myth of informal place-making: stitching and unstitching Atarim Square in Tel Aviv

The metaphor of stitching/unstitching can be applied to the mechanism employed by authorities, professionals and users alike—each for a different purpose and under different circumstances—for appropriating the urban space. It views the urban space as a socio-political arena that involves ongoing negotiation. The metaphor is used in this paper to debate some basic premises of architectural discourse of the everyday. Analysis of Atarim Square on Tel Aviv's shoreline—focusing on three periods: the 1930s, 1960s and the 1990s—reveals ongoing and often simultaneous processes of 'stitching and unstitching'. The key contention here is that formal (official and professional) spatial processes are not necessarily limiting, just as informal processes (personal and communal) are not always liberating, and that both are endemic to the socio-political construct of the everyday.     

The challenge of distance in designing civil protest: the case of Resurrection City in the Washington Mall and the Occupy Movement in Zuccotti Park

This paper focuses on the way people define and challenge practices of distance during protest and the way protesters disrupt ‘generally established and universally visible and valid distances’ associated with the place. In illuminating these ideas, two case studies with seemingly similar socio-spatial characteristics are explored. The first case was initiated by the Southern Christian Leadership Conference and aimed to call attention to the nation's neediest people by embarking on the ‘Poor People's Campaign’, which settled people on the National Mall in an encampment they called Resurrection City (RC). The second action, the Occupy Movement, was an international protest movement directed towards social and economic inequality. The Occupy Movement called upon protesters to ‘flood into lower Manhattan, set up tents, kitchens, peaceful barricades and occupy Wall Street for a few months’ to call attention to the inequalities of global capitalism. The paper interprets the strategies and tactics used by the Poor People's Campaign and the Occupy Movement to challenge distance, concluding with some reflections on the way contemporary forms of dissent are changing the way we perceive public space and its politics.     

Hardware Transactional Memory Exploration in Coherence-Free Many-Core Architectures

High-end embedded systems, like their general-purpose counterparts, are turning to many-core cluster-based shared-memory architectures that provide a shared memory abstraction subject to non-uniform memory access costs. In order to keep the cores and memory hierarchy simple, many-core embedded systems tend to employ simple, scratchpad-like memories, rather than hardware managed caches that require some form of cache coherence management. These “coherence-free” systems still require some means to synchronize memory accesses and guarantee memory consistency. Conventional lock-based approaches may be employed to accomplish the synchronization, but may lead to both usability and performance issues. Instead, speculative synchronization, such as hardware transactional memory, may be a more attractive approach. However, hardware speculative techniques traditionally rely on the underlying cache-coherence protocol to synchronize memory accesses among the cores. The lack of a cache-coherence protocol adds new challenges in the design of hardware speculative support. In this article, we present a new scheme for hardware transactional memory (HTM) support within a cluster-based, many-core embedded system that lacks an underlying cache-coherence protocol. We propose two alternative data versioning implementations for the HTM support, Full-Mirroring and Distributed Logging and we conduct a performance comparison between them. To the best of our knowledge, these are the first designs for speculative synchronization for this type of architecture. Through a set of benchmark experiments using our simulation platform, we show that our designs can achieve significant performance improvements over traditional lock-based schemes.     

Potency evaluation of a dermaseptin S4 derivative for antimicrobial food packaging applications

Antimicrobial packaging is part of the broader area of active packaging, in which the package absorbs/releases different compounds during the product's storage and plays a major role in maintaining quality, extending shelf‐life and improving the product's safety. Antimicrobial packages are capable of inhibiting the detrimental effects of spoiling microorganisms in food products. There has been very great interest in antimicrobial packaging in recent years and many such packaging materials have been proposed, some of which containing synthetic additives and others natural additives. In the present study, antimicrobial materials containing the antimicrobial peptide (AMP) dermaseptin K₄K₂₀‐S4, which shows cytolytic activity in vitro against a broad spectrum of pathogenic microorganisms, such as bacteria, protozoa, yeast and filamentous fungi, were investigated. The study was aimed at evaluating the potency of this AMP as an antimicrobial agent for antimicrobial food packaging in two forms: (a) an aqueous solution of AMP was applied onto a polyethylene shrink‐wrapping film; (b) the AMP was incorporated in a corn starch‐based coating and applied directly onto the foodstuff (fresh cucumbers). Of these two versions, the latter has shown a greater efficiency against moulds and aerobic bacteria, even at lower surface concentrations of AMP (4.5µg/dm² vs. 3.5–3.8µg/dm²) in the coating. While in the first version the AMP had slowed down the growth of microorganisms only slightly, incorporation of AMP into the coating caused a reduction in their concentration practically to zero. Copyright © 2006 John Wiley & Sons, Ltd.     

Flash-boiling atomization

Flash-boiling atomization is one of the most effective means of generating a fine and narrow-dispersed spray. Owing to its complexity its potential has not been fully realized to date. The paper reviews the present knowledge of the different mechanisms involved in the flash-boiling atomization process. These include intense nucleation, fast bubbles’ growth and liquid atomization. The inter-relationships between the distinctive processes determine the spray quality. Recent experimental observations and physical interpretations have improved our insight and led to better understanding of the whole process. One practical result is the establishment of design criteria for an optimal flash-boiling atomizing system.