Accelerator Memory Reuse in the Dark Silicon Era

Accelerators integrated on-die with General-Purpose CPUs (GP-CPUs) can yield significant performance and power improvements. Their extensive use, however, is ultimately limited by their area overhead; due to their high degree of specialization, the opportunity cost of investing die real estate on accelerators can become prohibitive, especially for general-purpose architectures. In this paper we present a novel technique aimed at mitigating this opportunity cost by allowing GP-CPU cores to reuse accelerator memory as a non-uniform cache architecture (NUCA) substrate. On a system with a last level-2 cache of 128kB, our technique achieves on average a 25% performance improvement when reusing four 512 kB accelerator memory blocks to form a level-3 cache. Making these blocks reusable as NUCA slices incurs on average in a 1.89% area overhead with respect to equally-sized ad hoc cache slice

Scalability of Optical Interconnects Based on Microring Resonators

This letter investigates the use of optical microring resonators as switching elements (SEs) in large optical interconnection fabrics. We introduce a simple physical-layer model to assess scalability in crossbar- and Benes-based architectures.We also propose a new dilated SE that improves scalability to build fabrics of several terabits per second of aggregate capacit

Spatial distribution of surface EMG on trapezius and lumbar muscles of violin and cello players in single note playing

Musicians activate their muscles in different patterns, depending on their posture, the instrument being played, and their experience level. Bipolar surface electrodes have been used in the past to monitor such activity, but this method is highly sensitive to the location of the electrode pair. In this work, the spatial distribution of surface EMG (sEMG) of the right trapezius and right and left erector spinae muscles were studied in 16 violin players and 11 cello players. Musicians played their instrument one string at a time in sitting position with/without backrest support. A 64 sEMG electrode (16x4) grid, 10mm inter-electrode distance (IED), was placed over the middle and lower trapezius (MT and LT) of the bowing arm. Two 16x2 electrode grids (IED=10mm) were placed on the left and right erector spinae muscles. Subjects played each of the four strings of the instrument either in large (1bow/s) or detaché tip/tail (8bows/s) bowing in two sessions (two days). In each of two days, measurements were repeated after half an hour of exercise to see the effect of exercise on the muscle activity and signal stability. A “muscle activity index” (MAI) was defined as the spatial average of the segmented active region of the RMS map. Spatial maps were automatically segmented using the watershed algorithm and thresholding. Results showed that, for violin players, sliding the bow upward from the tip toward the tail results in a higher MAI for the trapezius muscle than a downward bow. On the contrary, in cello players, higher MAI is produced in the tail to tip movement. For both instruments, an increasing MAI in the trapezius was observed as the string position became increasingly lateral, from string 1 (most medial) toward string 4 (most lateral). Half an hour of performance did not cause significant differences between the signal quality and the MAI values measured before and after the exercise. The MAI of the left and right erector spinae was smaller in the case of backrest support, especially for violin players. Back muscles of violin and cello players were activated asymmetrically, specifically in fast movements (detaché tip/tail). These findings demonstrate the sensitivity and stability of the technique and justify more extensive investigation following this proof of concept

Multi-sensor analysis of convective activity in central Italy during the HyMeX SOP 1.1

Abstract. A multi-sensor analysis of convective precipitation events that occurred in central Italy in autumn 2012 during the HyMeX (Hydrological cycle in the Mediterranean experiment) Special Observation Period (SOP) 1.1 is presented. Various microphysical properties of liquid and solid hydrometeors are examined to assess their relationship with lightning activity. The instrumentation used consisted of a C-band dual-polarization weather radar, a 2-D video disdrometer, and the LINET lightning network. Results of T-matrix simulation for graupel were used to (i) tune a fuzzy logic hydrometeor classification algorithm based on Liu and Chandrasekar (2000) for the detection of graupel from C-band dual-polarization radar measurements and (ii) to retrieve graupel ice water content. Graupel mass from radar measurements was related to lightning activity. Three significant case studies were analyzed and linear relations between the total mass of graupel and number of LINET strokes were found with different slopes depending on the nature of the convective event (such as updraft strength and freezing level height) and the radar observational geometry. A high coefficient of determination (R2 = 0.856) and a slope in agreement with satellite measurements and model results for one of the case studies (15 October 2012) were found. Results confirm that one of the key features in the electrical charging of convective clouds is the ice content, although it is not the only one. Parameters of the gamma raindrop size distribution measured by a 2-D video disdrometer revealed the transition from a convective to a stratiform regime. The raindrop size spectra measured by a 2-D video disdrometer were used to partition rain into stratiform and convective classes. These results are further analyzed in relation to radar measurements and to the number of strokes. Lightning activity was not always recorded when the precipitation regime was classified as convective rain. High statistical scores were found for relationships relating lightning activity to graupel aloft

A Multisensor Investigation of Convection During HyMeX SOP1 IOP13

A multisensor analysis of the convective precipitation event occurred over Rome during the IOP13 (October 15th, 2012) of the HyMeX (Hydrological cycle in the Mediterranean eXperiment) Special Observation Period (SOP) 1 is presented. Thanks to the cooperation among Italian meteorological services and scientific community and a specific agreement with NASA-GSFC, different types of devices for meteorological measurements were made available during the HyMeX SOP.1. For investigating this event, used are the 3-D lightning data provided by the LINET, the CNR ISAC dual-pol C-band radar (Polar 55C), located in Rome, the Drop Size Distributions (DSD) collected by the 2D Video Disdrometer (2DVD) and the collocated Micro Rain Radar (MRR) installed at the Radio Meteorology Lab. of "Sapienza" University of Rome, located 14 km from the Polar 55C radar. The relation between microphysical structure and electrical activity during the convective phase of the event was investigated using LINET lightning data and Polar 55C (working both in PPI and RHI scanning mode) observations. Location of regions of high horizontal reflectivity (Zh) values ( > 50 dBz), indicating convective precipitation, were found to be associated to a high number of LINET strokes. In addition, an hydrometeor classification scheme applied to the Polar 55C scans was used to detect graupel and to identify a relation between number of LINET strokes and integrated IWC of graupel along the event. Properties of DSDs measured by the 2DVD and vertical DSD profiles estimated by MRR and their relation with the lighting activity registered by LINET were investigated with specific focus on the transition from convective to stratiform regimes. A good agreement was found between convection detected by these instruments and the number of strokes detected by LINET

Crystallization and preliminary crystallographic studies on the large extracellular domain of human CD81, a tetraspanin receptor for hepatitis C virus

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Recombinant outer membrane vesicles carrying Chlamydia muridarum HtrA induce antibodies that neutralize chlamydial infection in vitro

Background: Outer membrane vesicles (OMVs) are spheroid particles released by all Gram-negative bacteria as a result of the budding out of the outer membrane. Since they carry many of the bacterial surface-associated proteins and feature a potent built-in adjuvanticity, OMVs are being utilized as vaccines, some of which commercially available. Recently, methods for manipulating the protein content of OMVs have been proposed, thus making OMVs a promising platform for recombinant, multivalent vaccines development. Methods: Chlamydia muridarum DO serine protease HtrA, an antigen which stimulates strong humoral and cellular responses in mice and humans, was expressed in Escherichia coli fused to the OmpA leader sequence to deliver it to the OMV compartment. Purified OMVs carrying HtrA (CM rHtrA-OMV) were analyzed for their capacity to induce antibodies capable of neutralizing Chlamydia infection of LLC-MK2 cells in vitro. Results: CM rHtrA-OMV immunization in mice induced antibodies that neutralize Chlamydial invasion as judged by an in vitro infectivity assay. This was remarkably different from what observed with an enzymatically functional recombinant HtrA expressed in, and purified from the E. coli cytoplasm (CM rHtrA). The difference in functionality between anti-CM rHtrA and anti-CM rHtrA-OMV antibodies was associated to a different pattern of protein epitopes recognition. The epitope recognition profile of anti-CM HtrA-OMV antibodies was similar to that induced in mice during Chlamydial infection. Conclusions: When expressed in OMVs HtrA appears to assume a conformation similar to the native one and this results in the elicitation of functional immune responses. These data further support the potentiality of OMVs as vaccine platform

Protein Array Profiling of Tic Patient Sera Reveals a Broad Range and Enhanced Immune Response against Group A Streptococcus Antigens

The human pathogen Group A Streptococcus (Streptococcus pyogenes, GAS) is widely recognized as a major cause of common pharyngitis as well as of severe invasive diseases and non-suppurative sequelae associated with the existence of GAS antigens eliciting host autoantibodies. It has been proposed that a subset of paediatric disorders characterized by tics and obsessive-compulsive symptoms would exacerbate in association with relapses of GAS-associated pharyngitis. This hypothesis is however still controversial. In the attempt to shed light on the contribution of GAS infections to the onset of neuropsychiatric or behavioral disorders affecting as many as 3% of children and adolescents, we tested the antibody response of tic patient sera to a representative panel of GAS antigens. In particular, 102 recombinant proteins were spotted on nitrocellulose-coated glass slides and probed against 61 sera collected from young patients with typical tic neuropsychiatric symptoms but with no overt GAS infection. Sera from 35 children with neither tic disorder nor overt GAS infection were also analyzed. The protein recognition patterns of these two sera groups were compared with those obtained using 239 sera from children with GAS-associated pharyngitis. This comparative analysis identified 25 antigens recognized by sera of the three patient groups and 21 antigens recognized by tic and pharyngitis sera, but poorly or not recognized by sera from children without tic. Interestingly, these antigens appeared to be, in quantitative terms, more immunogenic in tic than in pharyngitis patients. Additionally, a third group of antigens appeared to be preferentially and specifically recognized by tic sera. These findings provide the first evidence that tic patient sera exhibit immunological profiles typical of individuals who elicited a broad, specific and strong immune response against GAS. This may be relevant in the context of one of the hypothesis proposing that GAS antigen-dependent induction of autoantibodies in susceptible individuals may be involved the occurrence of tic disorders

Data-driven clustering of combined Functional Motor Disorders based on the Italian registry

Functional Motor Disorders (FMDs) represent nosological entities with no clear phenotypic characterization, especially in patients with multiple (combined FMDs) motor manifestations. A data-driven approach using cluster analysis of clinical data has been proposed as an analytic method to obtain non-hierarchical unbiased classifications. The study aimed to identify clinical subtypes of combined FMDs using a data-driven approach to overcome possible limits related to "a priori" classifications and clinical overlapping