On Performance Debugging of Unnecessary Lock Contentions on Multicore Processors: A Replay-based Approach

Locks have been widely used as an effective synchronization mechanism among processes and threads. However, we observe that a large number of false inter-thread dependencies (i.e., unnecessary lock contentions) exist during the program execution on multicore processors, thereby incurring significant performance overhead. This paper presents a performance debugging framework, PERFPLAY, to facilitate a comprehensive and in-depth understanding of the performance impact of unnecessary lock contentions. The core technique of our debugging framework is trace replay. Specifically, PERFPLAY records the program execution trace, on the basis of which the unnecessary lock contentions can be identified through trace analysis. We then propose a novel technique of trace transformation to transform these identified unnecessary lock contentions in the original trace into the correct pattern as a new trace free of unnecessary lock contentions. Through replaying both traces, PERFPLAY can quantify the performance impact of unnecessary lock contentions. To demonstrate the effectiveness of our debugging framework, we study five real-world programs and PARSEC benchmarks. Our experimental results demonstrate the significant performance overhead of unnecessary lock contentions, and the effectiveness of PERFPLAY in identifying the performance critical unnecessary lock contentions in real applications.Comment: 18 pages, 19 figures, 3 table

Do firms’ pension contributions decrease their investment efficiency in Chinese context?

Purpose: This research aims to investigate whether increasing the pension contributions of a firm leads to inefficient investments. Design/methodology/approach: Based on the 26 135 observations of the Chinese listed firms, this study employs ordinary least squares models to investigate the relationship between pension costs and inefficient investments. Findings/results: This study shows that Chinese listed firms’ pension contribution increments result in fewer investment opportunities and a decreased in investment efficiency. This is insignificant for the more profitable firms and state-owned enterprises. It suggests further that a firm’s pension cost is significantly associated with its investment inefficiency, particularly for cash flow dominated and financing–restricted firms. This indicates a negative association between pension contributions and cash flows, and several pension contributions may lead to a cash flow shortage in the firms. Practical implications: For managers, they should improve their investment efficiency within an affordable pension plan; for investors, increasing pension costs potentially decrease their investment returns. Originality/value: Some findings have reference values for some developing countries

Immune Responses in Mice Immunized with Mastitis Multiple Vaccines Using Different Adjuvants

Background: Bovine mastitis, a serious disease associated with both high incidence and significant economic losses, posing a major challenge to the global dairy industry. The development of vaccines for protection from new infections by mastitis pathogens is of considerable interest to the milk production industry. Vaccination is a common and easy strategy for the control of infectious diseases, and the adjuvants used in the formulation is a critical factor for vaccine efficacy improvement. The main objective of the present study was to evaluate three different adjuvants for their ability to enhance immune responses of mice that vaccinated with Bovine Mastitis Multiple Vaccine.Materials, Methods & Results: The thymus and spleen index, the phagocytic ability of macrophage and the serum antibody levels of mice were detected after vaccination, respectively. The results showed that the thymus index, spleen index, and the phagocytic ability of macrophage of mice in Aluminum group exhibited a significant higher level (P < 0.05) compared with those in the control groups. The difference of the serum antibody levels was significant (P < 0.05) between experimental groups and control group after vaccination. The serum antibody concentration of mice in FIA group was higher compared with other groups and had a longer duration. The antibody concentration of mice in France 206 oil group can not increase as fast as the antibody concentration of Aluminum group, but it can last a longer time at a high level. In conclusion, multiple vaccines mixed with three different adjuvants could enhance the immunity of mice and Freund’s incomplete adjuvant is the best choice for this vaccine.Discussion: Adjuvants play an important role in increasing the efficacy of a number of different vaccines. In this study, three kinds of adjuvants (Aluminum hydroxide, France 206 oil and FIA) were evaluated for their adjuvant effects for multiple vaccine of bovine mastitis in mice and aluminum hydroxide did best as the vaccine adjuvant from the results. Aluminum hydroxide is a universally accepted adjuvant for both human and veterinary vaccines. The goal of vaccination is to generate strong immune response providing protection against infection for a time. Different protective effects will usually obtained by different adjuvants even use same antigen. In this work, FIA, Alum and 206 oil were chosen as adjuvants for inactivated antigens of Streptococcus agalactiae, Streptococcus dysgalactiae and Staphylococcus aureus. The results showed that there was a significantly higher antibody levels in vaccinated mice compared with those in control group. In addition, the mice in France 206 oil and FIA group performed a higher antibody levels and stronger immunity than mice in Aluminum hydroxide groups. These findings suggest that Freund’s incomplete adjuvant (FIA) would be the best candidate as the adjuvant for mastitis multiple vaccines investigated in this study

4-(3-Carb­oxy­phen­yl)pyridinium nitrate

In the title salt, C12H10NO2 +·NO3 −, the dihedral angle between the pyridine ring and the benzene ring of the 4-(3-carb­oxy­phen­yl)pyridinium cation is 30.14 (2)°. Inversion-related pairs of cations are linked into dimers by pairs of O—H⋯O hydrogen bonds. Pairs of dimers are linked by N—H⋯O and C—H⋯O hydrogen bonds involving nitrate anions as acceptors, generating supra­molecular chains along the diagonal of the bc plane

What makes a good phorophyte? Predicting occupancy, species richness and abundance of vascular epiphytes in a lowland seasonal tropical forest

peer reviewedEpiphytes typically exhibit clustered distribution patterns, but predicting the spatial variation of their distribution at fine scales has long been a challenge. Taking advantage of a canopy crane giving access to 1.1 ha of lowland seasonal rainforest in Yunnan (China), we assess here which factors promote the probability that a given tree hosts epiphytes, and the variation of species richness and abundance of epiphytic spermatophytes and ferns among trees. Variation in epiphyte species richness as a function of host tree size, characteristics of its surrounding environment, topography and microclimatic conditions, were analyzed by Random Forest. Epiphytic spermatophytes and ferns occupied 2.3 and 10.8% of the available host trees, respectively. Significant models predicting which trees are more likely to host epiphytes than others were obtained, indicating that host tree characteristics and their local environment play a significant role in determining which host tree is most likely to be colonized. These models, as well as models for species richness and abundance, however, exhibited a moderate to low accuracy (r2 0.28 and 0.24 and of 0.12 and 0.14 for spermatophyte and fern richness and abundance, respectively). The best predictor of the presence of epiphytes on a tree, of its epiphytic species richness and abundance, was its DBH. In ferns, however, two peaks of species richness were observed, representing shade-loving ferns on small trees and sun-loving ferns on large trees. Microclimatic conditions and light intensity were the second best factor accounting for variation in species richness and abundance among trees. The contribution of liana infestation, host tree identity, and characteristics of neighboring trees were marginal. Our inclusion of a large number of host-tree characteristics and their local environment did not allow for an apparent improvement of model accuracy over studies with a more limited number of predictors, pointing to the role of chance upon tree colonization. Our results confirm the utmost importance of large trees with emergent canopies for the conservation of the epiphytic flora, but also indicate that epiphytic diversity assessments in tropical forests must also include small understorey trees, which should be further considered for conservation. The importance of the micro-climatic conditions that prevail at the level of each individual host tree further points to the necessity of maintaining a buffer zone around large host trees targeted for conservation

CPSAA: Accelerating Sparse Attention using Crossbar-based Processing-In-Memory Architecture

The attention mechanism requires huge computational efforts to process unnecessary calculations, significantly limiting the system's performance. Researchers propose sparse attention to convert some DDMM operations to SDDMM and SpMM operations. However, current sparse attention solutions introduce massive off-chip random memory access. We propose CPSAA, a novel crossbar-based PIM-featured sparse attention accelerator. First, we present a novel attention calculation mode. Second, we design a novel PIM-based sparsity pruning architecture. Finally, we present novel crossbar-based methods. Experimental results show that CPSAA has an average of 89.6X, 32.2X, 17.8X, 3.39X, and 3.84X performance improvement and 755.6X, 55.3X, 21.3X, 5.7X, and 4.9X energy-saving when compare with GPU, FPGA, SANGER, ReBERT, and ReTransformer.Comment: 14 pages, 19 figure

A turn-off fluorescent probe for the detection of Cu2+ based on a tetraphenylethylene-functionalized salicylaldehyde Schiff-base

A non-planar tetraphenylethylene-functionalized salicylaldehyde Schiff-base fluorescent probe (TPE-An-Py) with aggregation-induced enhanced emission (AIEE) characteristics was synthesized via a classical Knoevenagel condensation reaction, and exhibited a high sensitivity towards copper ions in aqueous media with a "turn-off" fluorescence mechanism; the limit of detection is 2.36 × 10-7 mol L-1. Importantly, the coordination mode of the probe towards copper was further evaluated by UV-vis and NMR spectroscopy and a 1:2 stoichiometry was identified. A single crystal X-ray diffraction study confirmed the binding mode. In addition, the AIEE fluorescent probe can be applied to the detection of Cu2+ in practical samples with satisfactory recoveries in a range of 106-111% in lake water and 97-108% in tap water

Density Matrix in Quantum Mechanics and Distinctness of Ensembles Having the Same Compressed Density Matrix

We clarify different definitions of the density matrix by proposing the use of different names, the full density matrix for a single-closed quantum system, the compressed density matrix for the averaged single molecule state from an ensemble of molecules, and the reduced density matrix for a part of an entangled quantum system, respectively. We show that ensembles with the same compressed density matrix can be physically distinguished by observing fluctuations of various observables. This is in contrast to a general belief that ensembles with the same compressed density matrix are identical. Explicit expression for the fluctuation of an observable in a specified ensemble is given. We have discussed the nature of nuclear magnetic resonance quantum computing. We show that the conclusion that there is no quantum entanglement in the current nuclear magnetic resonance quantum computing experiment is based on the unjustified belief that ensembles having the same compressed density matrix are identical physically. Related issues in quantum communication are also discussed.Comment: 26 pages. To appear in Foundations of Physics, 36 (8), 200