The ARGUS Vertex Trigger

A fast second level trigger has been developed for the ARGUS experiment which recognizes tracks originating from the interaction region. The processor compares the hits in the ARGUS Micro Vertex Drift Chamber to 245760 masks stored in random access memories. The masks which are fully defined in three dimensions are able to reject tracks originating in the wall of the narrow beampipe of 10.5\,mm radius.Comment: gzipped Postscript, 27 page

Improved quality of online education using prioritized multi-agent reinforcement learning for video traffic scheduling

The recent global pandemic has transformed the way education is delivered, increasing the importance of videobased online learning. However, this puts a significant pressure on the underlying communication networks and the limited available bandwidth needs to be intelligently allocated to support a much higher transmission load, including video-based services. In this context, this paper proposes a Machine Learning (ML)-based solution that dynamically prioritizes content viewers with heterogeneous video services to increase their Quality of Service (QoS) and perceived Quality of Experience (QoE). The proposed approach makes use of the novel Prioritized Multi- Agent Reinforcement Learning solution (PriMARL) to decide the prioritization order of the video-based services based on networking conditions. However, the performance in terms of QoS and QoE provisioning to learners with different profiles and networking conditions depends on the type of scheduler employed in the frequency domain to conduct the scheduling and the radio resource allocation. To decide the best approach to be followed, we employ the proposed PriMARL solution with different types of scheduling rules and compare them with other state-of-theart solutions in terms of throughput, delay, packet loss, Peak Signal-to-Noise Ratio (PSNR), and Mean Opinion Score (MOS) for different traffic loads and characteristics. We show that the proposed solution achieves the best user QoE results

Degradation of the mycotoxin fusaric acid in burkholderia ambifaria t16: genes and metabolic pathways involved

Fusaric acid (FA, 5-butylpyridine, 2-carboxylic acid) is a secondary metabolite produced by several Fusarium species, which is toxic for bacteria, plants, animals and humans. This mycotoxin contributes to the virulence of phytopathogenic Fusarium in several crops, causing important economic losses. Moreover, FA reduces survival and competition abilities of bacterial species able to antagonize Fusarium spp. due to its negative effects on viability and production of antibiotics effective against these fungi. Burkholderia ambifaria T16 is a bacterial strain isolated from the rhizosphere of barley that showed the interesting ability to degrade FA and detoxify this mycotoxin from barley seedlings. The genes and metabolic pathways involved in FA degradation have not been identified so far in any bacterial species. By screening of a transposon insertion library and proteomic analysis we were able to identify genes and metabolic pathways that would be involved in FA degradation. A functional 2-methylcitrate cycle (2-MCC), a carbon anaplerotic pathway widely distributed among bacteria and fungi where propionyl-CoA is converted to pyruvate and succinate, was shown to be essential for the growth of B. ambifaria T16 in the presence of FA. Propionyl-CoA and its derived catabolites are lethally toxic to cells when accumulate. For that reason, besides providing succinate and pyruvate, the 2-MCC also has a very important role in the detoxification of propionyl-CoA and its catabolites. The comparison of the proteomic profile of B. ambifaria T16 growing with FA or citrate as sole carbon sources showed that more than 50 enzymes were significantly overexpressed during growth with FA, including 2-MCC enzymes and enzymes that convert butyryl-CoA to propanoyl-CoA, suggesting that propanoyl-CoA is produced during FA degradation. Moreover, several proteins, including an AraC-type transcriptional regulator, a FMN-dependent two-component luciferase like monooxygenase (LLM) system, an amidohydrolase, two enoyl-CoA hydratases and a long-chain fatty acid ligase, encoded in the same gene cluster, were highly over-expressed during growth with FA (>10 fold up-regulation). In the last years, two-component LLMs were shown to catalyze the pyridine-ring cleavage of several N-heterocyclic compounds, suggesting that the mentioned gene cluster is a good candidate to be involved in the initial steps of FA degradation in B. ambifaria T16.Fil: Vinacour, Matias Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; ArgentinaFil: Forne, I.. Ludwig Maximilians Universitat; AlemaniaFil: Jung, K.. Ludwig Maximilians Universitat; AlemaniaFil: Imhof, A.. Ludwig Maximilians Universitat; AlemaniaFil: Ruiz, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; ArgentinaLVII SAIB Meeting; XVI SAMIGE MeetingCiudad Autonoma de Buenos AiresArgentinaSociedad Argentina de Investigación Bioquímica y Biología MolecularSociedad Argentina de Microbiología Genera

Near-Surface Scattering From High Velocity Carbonates In West Texas

Seismic data acquired directly over near-surface limestone formations are commonly observed to be of inferior quality. A possible cause for this degradation is scattering in the near-subsurface by, e.g., the weathering layer, rough free-surface topography, or heterogeneities such as cavities or clusters of vugs. We applied different numerical scattering schemes to study the effects of each of these three scattering mechanisms. For a particular dataset acquired in West Texas, we find that a weathering layer is the dominant cause of noise on records acquired in valleys. However on mesas, nearsubsurface heterogeneity is the primary cause of scattered wave-energy. Topography turned out to be of only secondary importance. As additional attributes, we use energy-density and energy-flux vectors to study the frequency dependence of the different scattering models. These attributes allow us to study where energy concentrates and in which direction it flows. For example, we observed that near sub-surface heterogeneities build up waveguides which efficiently trap seismic energy near the surface.Massachusetts Institute of Technology. Borehole Acoustics and Logging Consortiu

The Vibrational Spectrum of the hydrated Alanine-Leucine Peptide in the Amide region from IR experiments and First Principles Calculation

We have combined infrared (IR) experiments with molecular dynamics (MD) simulations in solution at finite temperature to analyse the vibrational signature of the small floppy peptide Alanine-Leucine. IR spectra computed from first- principles MD simulations exhibit no distinct differences between conformational clusters of alpha-helix/beta-sheet-like folds with different orientations of the bulky leucine side chain. All computed spectra show two prominent bands, in good agreement with the experiment, that are assigned to the stretch vibrations of the carbonyl and carboxyl group, respectively. Variations in band widths and exact maxima are likely due to small fluctuations in the backbone torsion angles

Visual intracortical and transthalamic pathways carry distinct information to cortical areas.

Sensory processing involves information flow between neocortical areas, assumed to rely on direct intracortical projections. However, cortical areas may also communicate indirectly via higher-order nuclei in the thalamus, such as the pulvinar or lateral posterior nucleus (LP) in the visual system of rodents. The fine-scale organization and function of these cortico-thalamo-cortical pathways remains unclear. We find that responses of mouse LP neurons projecting to higher visual areas likely derive from feedforward input from primary visual cortex (V1) combined with information from many cortical and subcortical areas, including superior colliculus. Signals from LP projections to different higher visual areas are tuned to specific features of visual stimuli and their locomotor context, distinct from the signals carried by direct intracortical projections from V1. Thus, visual transthalamic pathways are functionally specific to their cortical target, different from feedforward cortical pathways, and combine information from multiple brain regions, linking sensory signals with behavioral context

Calibration of <i>Herschel</i> SPIRE FTS observations at different spectral resolutions

The SPIRE Fourier Transform Spectrometer on-board the Herschel Space Observatory had two standard spectral resolution modes for science observations: high resolution (HR) and low resolution (LR), which could also be performed in sequence (H+LR). A comparison of the HR and LR resolution spectra taken in this sequential mode revealed a systematic discrepancy in the continuum level. Analysing the data at different stages during standard pipeline processing demonstrates that the telescope and instrument emission affect HR and H+LR observations in a systematically different way. The origin of this difference is found to lie in the variation of both the telescope and instrument response functions, while it is triggered by fast variation of the instrument temperatures. As it is not possible to trace the evolution of the response functions using housekeeping data from the instrument subsystems, the calibration cannot be corrected analytically. Therefore, an empirical correction for LR spectra has been developed, which removes the systematic noise introduced by the variation of the response functions

Scaled penalization of Brownian motion with drift and the Brownian ascent

We study a scaled version of a two-parameter Brownian penalization model introduced by Roynette-Vallois-Yor in arXiv:math/0511102. The original model penalizes Brownian motion with drift $h\in\mathbb{R}$ by the weight process ${\big(\exp(\nu S_t):t\geq 0\big)}$ where $\nu\in\mathbb{R}$ and $\big(S_t:t\geq 0\big)$ is the running maximum of the Brownian motion. It was shown there that the resulting penalized process exhibits three distinct phases corresponding to different regions of the $(\nu,h)$-plane. In this paper, we investigate the effect of penalizing the Brownian motion concurrently with scaling and identify the limit process. This extends a result of Roynette-Yor for the ${\nu<0,~h=0}$ case to the whole parameter plane and reveals two additional "critical" phases occurring at the boundaries between the parameter regions. One of these novel phases is Brownian motion conditioned to end at its maximum, a process we call the Brownian ascent. We then relate the Brownian ascent to some well-known Brownian path fragments and to a random scaling transformation of Brownian motion recently studied by Rosenbaum-Yor.Comment: 32 pages; made additions to Section

Systematic characterisation of the Herschel SPIRE Fourier Transform Spectrometer

A systematic programme of calibration observations was carried out to monitor the performance of the SPIRE FTS instrument on board the Herschel Space Observatory. Observations of planets (including the prime point-source calibrator, Uranus), asteroids, line sources, dark sky, and cross-calibration sources were made in order to monitor repeatability and sensitivity, and to improve FTS calibration. We present a complete analysis of the full set of calibration observations and use them to assess the performance of the FTS. Particular care is taken to understand and separate out the effect of pointing uncertainties, including the position of the internal beam steering mirror for sparse observations in the early part of the mission. The repeatability of spectral line centre positions is <5km/s, for lines with signal-to-noise ratios >40, corresponding to <0.5-2.0% of a resolution element. For spectral line flux, the repeatability is better than 6%, which improves to 1-2% for spectra corrected for pointing offsets. The continuum repeatability is 4.4% for the SLW band and 13.6% for the SSW band, which reduces to ~1% once the data have been corrected for pointing offsets. Observations of dark sky were used to assess the sensitivity and the systematic offset in the continuum, both of which were found to be consistent across the FTS detector arrays. The average point-source calibrated sensitivity for the centre detectors is 0.20 and 0.21 Jy [1 sigma; 1 hour], for SLW and SSW. The average continuum offset is 0.40 Jy for the SLW band and 0.28 Jy for the SSW band.Comment: 41 pages, 37 figures, 32 tables. Accepted for publication in MNRA