Limit order books and trade informativeness

In the microstructure literature, information asymmetry is an important determinant of market liquidity. The classic setting is that uninformed dedicated liquidity suppliers charge price concessions when incoming market orders are likely to be informationally motivated. In limit order book markets, however, this relationship is less clear, as market participants can switch roles, and freely choose to immediately demand or patiently supply liquidity by submitting either market or limit orders. We study the importance of information asymmetry in limit order books based on a recent sample of thirty German DAX stocks. We find that Hasbrouck’s (1991) measure of trade informativeness Granger-causes book liquidity, in particular that required to fill large market orders. Picking-off risk due to public news induced volatility is more important for top-of-the book liquidity supply. In our multivariate analysis we control for volatility, trading volume, trading intensity and order imbalance to isolate the effect of trade informativeness on book liquidity. JEL Classification: G14 Keywords: Price Impact of Trades , Trading Intensity , Dynamic Duration Models, Spread Decomposition Models , Adverse Selection Ris

University Downtown Campuses and Community Engagement in Small and Midsized Citites

In summer of 2011, as a graduate intern from the Master of Public Administration (MPA) program I conducted a research project under the supervision of the Director of Special Programs for Economic Development. The purpose of the project was to learn about the perceptions of downtown area officials and community members regarding the impact of the Binghamton University Downtown Center (UDC). Findings showed that overall participants were satisfied regarding UDC partnering relationships with public and non-profits agencies. At the same time, the findings also indicated that participants had unmet expectations regarding the UDC participation in various downtown activities. In order to help address the issue, I conducted semi-structured telephone interviews with participants from seventeen universities to examine successful community engagement practices. All of the universities selected for these interviews have been recognized for successful community engagement practices. All of the universities selected for these interviews have been recognized for successful relationships with host communities, are located in a small or medium-sized city in the United States, and currently have a downtown campus or a physical presence in the downtown area of their cities

The role of nitrogen uptake on the competition ability of three vineyard Saccharomyces cerevisiae strains

Three vineyard strains of Saccharomyces cerevisiae, P301.4, P304.4 and P254.12, were assayed in comparison with a commercial industrial strain, QA23. The aim was to understand if nitrogen availability could influence strain competition ability during must fermentation. Pairwise-strain fermentations and co-fermentations with the simultaneous presence of the four strains were performed in synthetic musts at two nitrogen levels: control nitrogen condition (CNC) that assured the suitable assimilable nitrogen amount required by the yeast strains to complete the fermentation and low nitrogen condition (LNC) where nitrogen is present at very low level. Results suggested a strong involvement of nitrogen availability, as the frequency in must of the vineyard strains, respect to QA23, in LNC was always higher than that found in CNC. Moreover, in CNC only strain P304.4 reached the same strain frequency as QA23. P304.4 competition ability increased during the fermentation, indicating better performance when nitrogen availability was dropping down. P301.4 was the only strain sensitive to QA23 killer toxin. In CNC, when it was co-inoculated with the industrial strain QA23, P301.4 was never detected. In LNC, P301.4 after 12 h accounted for 10% of the total population. This percentage increased after 48 h (20%). Single-strain fermentations were also run in both conditions and the nitrogen metabolism further analyzed. Fermentation kinetics, ammonium and amino-acid consumptions and the expression of genes under nitrogen catabolite repression evidenced that vineyard yeasts, and particularly strain P304.4, had higher nitrogen assimilation rate than the commercial control. In conclusion, the high nitrogen assimilation rate seems to be an additional strategy that allowed vineyard yeasts successful competition during the growth in grape musts

Implementació de Serveis Telemàtics Bàsics

El projecte Implementació de Serveis Telemàtics Bàsics exposa una solució integral i centralitzada que instal·la i gestiona de manera ràpida i senzilla un servidor que ofereix serveis telemàtics bàsics. Els serveis de xarxa orientats a l'usuari engloben el servei web, el servei de correu, el servei de transferència de fitxers i el servei de missatgeria instantània. Els serveis orientats al treball en xarxa són aquells serveis que són transparents per a l'usuari, però indispensables per al funcionament de la resta de serveis. Aquests serveis són: el servei de màquines virtuals, el servei d'autenticació, el servei de resolució de noms i el servei de base de dades. La implantació d'aquesta solució aconsegueix classificar els dominis d'Internet que un servidor ha d'administrar, i adjudicar-li o no els serveis abans descrits, així com el manteniment dels usuaris de cada domini. A més, dins de cada domini, es garanteix la unicitat d'usuaris

A Linux Kernel Scheduler Extension for Multi-core Systems

The Linux kernel is mostly designed for multi-programed environments, but high-performance applications have other requirements. Such applications are run standalone, and usually rely on runtime systems to distribute the application's workload on worker threads, one per core. However, due to current OSes limitations, it is not feasible to track whether workers are actually running or blocked due to, for instance, a requested resource. For I/O intensive applications, this leads to a significant performance degradation given that the core of a blocked thread becomes idle until it is able to run again. In this paper, we present the proof-of-concept of a Linux kernel extension denoted User-Monitored Threads (UMT) which tackles this problem. Our extension allows a user-space process to be notified of when the selected threads become blocked or unblocked, making it possible for a runtime to schedule additional work on the idle core. We implemented the extension on the Linux Kernel 5.1 and adapted the Nanos6 runtime of the OmpSs-2 programming model to take advantage of it. The whole prototype was tested on two applications which, on the tested hardware and the appropriate conditions, reported speedups of almost 2x.Comment: 10 pages, 5 figures, conferenc

A native tensor-vector multiplication algorithm for high performance computing

Tensor computations are important mathematical operations for applications that rely on multidimensional data. The tensor-vector multiplication (TVM) is the most memory-bound tensor contraction in this class of operations. This paper proposes an open-source TVM algorithm which is much simpler and efficient than previous approaches, making it suitable for integration in the most popular BLAS libraries available today. Our algorithm has been written from scratch and features unit-stride memory accesses, cache awareness, mode obliviousness, full vectorization and multi-threading as well as NUMA awareness for non-hierarchically stored dense tensors. Numerical experiments are carried out on tensors up to order 10 and various compilers and hardware architectures equipped with traditional DDR and high bandwidth memory (HBM). For large tensors the average performance of the TVM ranges between 62% and 76% of the theoretical bandwidth for NUMA systems with DDR memory and remains independent of the contraction mode. On NUMA systems with HBM the TVM exhibits some mode dependency but manages to reach performance figures close to peak values. Finally, the higher-order power method is benchmarked with the proposed TVM kernel and delivers on average between 58% and 69% of the theoretical bandwidth for large tensors.This work was supported in part by MCIN/AEI and ESF under Grant RYC2019-027592-I, and in part by the HPC Technology Innovation Lab, a Barcelona Supercomputing Center and Huawei research cooperation agreement (2020).Peer ReviewedPostprint (author's final draft