CrisMap: A Big Data Crisis Mapping System Based on Damage Detection and Geoparsing

Natural disasters, as well as human-made disasters, can have a deep impact on wide geographic areas, and emergency responders can benefit from the early estimation of emergency consequences. This work presents CrisMap, a Big Data crisis mapping system capable of quickly collecting and analyzing social media data. CrisMap extracts potential crisis- related actionable information from tweets by adopting a classification technique based on word embeddings and by exploiting a combination of readily-available semantic annotators to geoparse tweets. The enriched tweets are then visualized in customizable, Web-based dashboards, also leveraging ad-hoc quantitative visualizations like choropleth maps. The maps produced by our system help to estimate the impact of the emergency in its early phases, to identify areas that have been severely struck, and to acquire a greater situational awareness. We extensively benchmark the performance of our system on two Italian natural disasters by validating our maps against authoritative data. Finally, we perform a qualitative case-study on a recent devastating earthquake occurred in Central Italy

A Highly Scalable Parallel Caching System for Web Search Engine Results

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Index ordering by query-independent measures

Conventional approaches to information retrieval search through all applicable entries in an inverted file for a particular collection in order to find those documents with the highest scores. For particularly large collections this may be extremely time consuming. A solution to this problem is to only search a limited amount of the collection at query-time, in order to speed up the retrieval process. In doing this we can also limit the loss in retrieval efficacy (in terms of accuracy of results). The way we achieve this is to firstly identify the most “important” documents within the collection, and sort documents within inverted file lists in order of this “importance”. In this way we limit the amount of information to be searched at query time by eliminating documents of lesser importance, which not only makes the search more efficient, but also limits loss in retrieval accuracy. Our experiments, carried out on the TREC Terabyte collection, report significant savings, in terms of number of postings examined, without significant loss of effectiveness when based on several measures of importance used in isolation, and in combination. Our results point to several ways in which the computation cost of searching large collections of documents can be significantly reduced

Distinct subsynaptic localization of type 1 metabotropic glutamate receptors at glutamatergic and GABAergic synapses in the rodent cerebellar cortex

Type 1 metabotropic glutamate (mGlu1) receptors play a pivotal role in different forms of synaptic plasticity in the cerebellar cortex, e.g. long-term depression at glutamatergic synapses and rebound potentiation at GABAergic synapses. These various forms of plasticity might depend on the subsynaptic arrangement of the receptor in Purkinje cells that can be regulated by protein-protein interactions. This study investigated, by means of the freeze-fracture replica immunogold labelling method, the subcellular localization of mGlu1 receptors in the rodent cerebellum and whether Homer proteins regulate their subsynaptic distribution. We observed a widespread extrasynaptic localization of mGlu1 receptors and confirmed their peri-synaptic enrichment at glutamatergic synapses. Conversely, we detected mGlu1 receptors within the main body of GABAergic synapses onto Purkinje cell dendrites. Although Homer proteins are known to interact with the mGlu1 receptor C-terminus, we could not detect Homer3, the most abundant Homer protein in the cerebellar cortex, at GABAergic synapses by pre-embedding and post-embedding immunoelectron microscopy. We then hypothesized a critical role for Homer proteins in the peri-junctional localization of mGlu1 receptors at glutamatergic synapses. To disrupt Homer-associated protein complexes, mice were tail-vein injected with the membrane-permeable dominant-negative TAT-Homer1a. Freeze-fracture replica immunogold labelling analysis showed no significant alteration in the mGlu1 receptor distribution pattern at parallel fibre-Purkinje cell synapses, suggesting that other scaffolding proteins are involved in the peri-synaptic confinement. The identification of interactors that regulate the subsynaptic localization of the mGlu1 receptor at neurochemically distinct synapses may offer new insight into its trafficking and intracellular signalling

SHANK3 mutations identified in autism lead to modification of dendritic spine morphology via an actin-dependent mechanism

Genetic mutations of SHANK3 have been reported in patients with intellectual disability, autism spectrum disorder (ASD) and schizophrenia. At the synapse, Shank3/ProSAP2 is a scaffolding protein that connects glutamate receptors to the actin cytoskeleton via a chain of intermediary elements. Although genetic studies have repeatedly confirmed the association of SHANK3 mutations with susceptibility to psychiatric disorders, very little is known about the neuronal consequences of these mutations. Here, we report the functional effects of two de novo mutations (STOP and Q321R) and two inherited variations (R12C and R300C) identified in patients with ASD. We show that Shank3 is located at the tip of actin filaments and enhances its polymerization. Shank3 also participates in growth cone motility in developing neurons. The truncating mutation (STOP) strongly affects the development and morphology of dendritic spines, reduces synaptic transmission in mature neurons and also inhibits the effect of Shank3 on growth cone motility. The de novo mutation in the ankyrin domain (Q321R) modifies the roles of Shank3 in spine induction and morphology, and actin accumulation in spines and affects growth cone motility. Finally, the two inherited mutations (R12C and R300C) have intermediate effects on spine density and synaptic transmission. Therefore, although inherited by healthy parents, the functional effects of these mutations strongly suggest that they could represent risk factors for ASD. Altogether, these data provide new insights into the synaptic alterations caused by SHANK3 mutations in humans and provide a robust cellular readout for the development of knowledge-based therapies

Successful Cognitive Aging in Rats: A Role for mGluR5 Glutamate Receptors, Homer 1 Proteins and Downstream Signaling Pathways

Normal aging is associated with impairments in cognition, especially learning and memory. However, major individual differences are known to exist. Using the classical Morris Water Maze (MWM) task, we discriminated a population of 24-months old Long Evans aged rats in two groups - memory-impaired (AI) and memory-unimpaired (AU) in comparison with 6-months old adult animals. AI rats presented deficits in learning, reverse memory and retention. At the molecular level, an increase in metabotropic glutamate receptors 5 (mGluR5) was observed in post-synaptic densities (PSD) in the hippocampus of AU rats after training. Scaffolding Homer 1b/c proteins binding to group 1 mGluR facilitate coupling with its signaling effectors while Homer 1a reduces it. Both Homer 1a and 1b/c levels were up-regulated in the hippocampus PSD of AU animals following MWM task. Using immunohistochemistry we further demonstrated that mGluR5 as well as Homer 1b/c stainings were enhanced in the CA1 hippocampus sub-field of AU animals. In fact mGluR5 and Homer 1 isoforms were more abundant and co-localized in the hippocampal dendrites in AU rats. However, the ratio of Homer 1a/Homer 1b/c bound to mGluR5 in the PSD was four times lower for AU animals compared to AI rats. Consequently, AU animals presented higher PKCγ, ERK, p70S6K, mTOR and CREB activation. Finally the expression of immediate early gene Arc/Arg3.1 was shown to be higher in AU rats in accordance with its role in spatial memory consolidation. On the basis of these results, a model of successful cognitive aging with a critical role for mGluR5, Homer 1 proteins and downstream signalling pathways is proposed here

A Highly Scalable Parallel Caching System for Web Search Engine Results

This paper discusses the design and implementation of SDC, a new caching strategy aimed to e#ciently exploit the locality present in the stream of queries submitted to a Web Search Engine. SDC stores the results of the most frequently submitted queries in a fixed-size read-only portion of the cache, while the queries that cannot be satisfied by the static portion compete for the remaining entries of the cache according to a given cache replacement policy. We experimentally demonstrated the superiority of SDC over purely static and dynamic policies by measuring the hit-ratio achieved on two large query logs by varying cache parameters and the replacement policy used. Finally, we propose an implementation optimized for concurrent accesses, and we accurately evaluate its scalability

GKAP-DLC2 interaction organizes the postsynaptic scaffold complex to enhance synaptic NMDA receptor activity

International audienceAt glutamatergic brain synapses, scaffolding proteins regulate receptor location and function. The targeting and organization of scaffolding proteins in the postsynaptic density (PSD) is poorly understood, but it is known that a core protein of the glutamatergic receptor postsynaptic scaffold complex, guanylate-kinase-associated protein (GKAP) interacts with dynein light chain 2 (DLC2, also known as DYNLL2), a protein associated with molecular motors. In the present study, we combined BRET imaging, immunostaining and electrophysiological recording to assess the role of the GKAP-DLC2 interaction in the functional organization of the glutamatergic synapse. We found that GKAP-DLC2 interaction in dendritic spine stabilizes scaffolding protein expression at the PSD and enhances synaptic NMDA receptor activity. Moreover, the GKAP-DLC2 functional interaction is favored by sustained synaptic activity. These data identify a regulatory pathway of synaptic transmission that depends on activity-induced remodelling of the postsynaptic scaffold protein complex

Boosting the Performance of Web Search Engines: Caching and Prefetching Query Results by Exploiting Historical Usage Data

This article discusses efficiency and effectiveness issues in caching the results of queries submitted to a Web search engine (WSE). We propose SDC (Static Dynamic Cache), a new caching strategy aimed to efficiently exploit the temporal and spatial locality present in the stream of processed queries. SDC extracts from historical usage data the results of the most frequently submitted queries and stores them in a static, read-only portion of the cache. The remaining entries of the cache are dynamically managed according to a given replacement policy and are used for those queries that cannot be satisfied by the static portion. Moreover, we improve the hit ratio of SDC by using an adaptive prefetching strategy, which anticipates future requests by introducing a limited overhead over the back-end WSE. We experimentally demonstrate the superiority of SDC over purely static and dynamic policies by measuring the hit ratio achieved on three large query logs by varying the cache parameters and the replacement policy used for managing the dynamic part of the cache. Finally, we deploy and measure the throughput achieved by a concurrent version of our caching system. Our tests show how the SDC cache can be efficiently exploited by many threads that concurrently serve the queries of different users