Study of the performance of the LHCb MWPC with cosmic rays

In this note we report the results of measurements performed with cosmic rays on different LHCb Muon Chambers. The main characteristics of the chambers have been investigated as a function of the high voltage value in order to achieve a better comprehension of the detector performance both for optimizing the chamber working conditions on the experimental apparatus and for providing useful information for the Monte Carlo simulation

A new method based on noise counting to monitor the frontend electronics of the LHCb muon detector

A new method has been developed to check the correct behaviour of the frontend electronics of the LHCb muon detector. This method is based on the measurement of the electronic noise rate at different thresholds of the frontend discriminator. The method was used to choose the optimal discriminator thresholds. A procedure based on this method was implemented in the detector control system and allowed the detection of a small percentage of frontend channels which had deteriorated. A Monte Carlo simulation has been performed to check the validity of the method

Can bacteriofages be effective in controlling harmful biofilms?

(Bacterio)phages are viruses that specifically infect bacteria, causing cell lysis and therefore can be considered a valuable strategy for bacterial control. Recent studies have demonstrated the potential of using phages to control bacterial biofilms. Phages are able to penetrate the extracellular matrnc and can cause up to 90% of biofilm mass reduction even in old biofilms. However phage action can be impaired by components of the biofilm matrix, the slow growth of biofilm bacteria and the fast emergence of phage resistant phenotypes. We have conducted several studies of phage biofilm interaction and based on our experimental data, we have hypothesized that the general mechanisms of a virulent phage-biofilm infection, in a very simplistic model, can occur in four stages: 1) Transport of the phage particles through the biofilm matrix (by diffusion or convection mechanisms); 2) Settlement and/or attachment of phages onto bacterial cells embedded in the biofilm matrix, followed by adsorption and phage replicatiOn inside host cells; 3) Release of phage progeny to planktonic and biofilm phases, through host cell lysis and infection of neighbourhood biofilm cells resulting in biofilm biomomass reduct1on; 4) Detachment of biofilm portions and phages into the planktomc phase. Nevertheless, the interaction between phage and biofilms is a rather complex process. Theoretically, a biofilm should be rapidly infected because cells are more close to each other and this fact can enhance phage replication, when compared to the less accessible bacteria of planktonic cultures. On the other hand, the structure and compositiOn of the biofilm as well the physiology of the biofilm cells may impose some limitations to biofilm infection. Indeed, phage·biofilm interaction is greatly inFluenced by the biofilm age, biofilm structure, biofilm mode of growth and most importantly the host and phage characteristics. This work is a summary of all phage/biofilm interaction studies conducted by our team involving different phage types and host species

Stereoselective Synthesis of α,α’-Dihydroxy-β,β’-diaryl-β-amino Acids by Mannich-like Condensation of Hydroarylamides

Dual \u3b1,\u3b1\u2019-Dihydroxy-\u3b2-amino acids are very interesting tools for several industrial applications. Nevertheless, few derivatives are reported in the literature concerning the substitution pattern as well as their enantioselective syntheses are lacking. Here, we report on the preparation of enantiopure \u3b1,\u3b1\u2019-dihydroxy-\u3b2,\u3b2\u2019-diaryl-\u3b2-amino acid (dual) derivatives by an efficient Mannich-like condensation of hydroarylamides with 5,6-diethoxy-5,6-dimethyl-1,4-dioxan-2-one (triethylsilyl)ketene acetal. The synthetic protocol has been optimized affording the dual compounds in very good yields and with different aryl substitution patterns. Taking advantage of the \u201cdouble stereodifferentiation\u201d concept, a highly stereoselective reaction was performed: of the 16 possible isomers, only two diastereoisomers (d.r. up to 93:7) formed. Insights on the high stereocontrol of this condensation were given

Performance of clonal rootstocks for "BRS-Kampai" peach and own-rooted trees in a mild-winter region.

Abstract: The worldwide main peach-producing are adopting peach training systems with canopy size-controlling clonal rootstocks. However, most peach seedlings commercialised in Brazil are still on seed-propagated rootstocks, which are vigorous and heterogeneous. This study aimed to select rootstocks which induce desirable characteristics of fruit quality, yield efficiency, size control, adaptability and stability in the ‘BRS-Kampai’ grown in subtropical regions with mild winters. We used adaptability and stability methodology and multivariate selection index to determine yield components and fruit quality. The experiment was conducted in five cycles. The treatments consisted of ‘BRS-Kampai’ grafted onto 17 clonal rootstocks of Prunus spp. and own-rooted trees. The evaluated variables were yield per tree, yield per area, fruit mass, fruit diameter, fruit firmness, soluble solids content, titratable acidity, canopy volume and yield efficiency. The rootstocks ‘Ishtara®’, ‘Genovesa’, ‘Santa Rosa’ and ‘Cadaman’ always induced low yield and low fruit quality when used as clonal rootstocks for the ‘BRS-Kampai’ and showed no potential for use as rootstocks in subtropical humid regions with mild winters. The ‘BRS-Kampai’ own-rooted peach trees or those grafted onto ‘Flordaguard’, ‘Okinawa’ are alternatives for peach cultivation under the edaphoclimatic conditions of Pato Branco-PR, although the training and pruning systems must be adjusted due to high vigour. The clonal rootstocks ‘Tsukuba-3’ and ‘Tsukuba-2’ induced the highest production performance in the canopy cultivar BRS-Kampai, combining fruit quality, yield with higher stability, and yield efficiency making them the most suitable ones among the studied rootstocks. Resumo: Sistemas de condução de pessegueiros com porta-enxertos clonais que reduzem vigor da copa são os mais adotados mundialmente. Entretanto, no Brasil ainda se utiliza porta-enxertos propagados por sementes, que são vigorosos e heterogêneos. Este trabalho teve como objetivo selecionar porta-enxertos que induzam qualidade de frutos, eficiência produtiva, controle de vigor, adaptabilidade e estabilidade em ‘BRS-Kampai’ cultivada em regiões subtropicais com invernos amenos. Foram utilizadas metodologias de adaptabilidade e estabilidade e índice de seleção multivariada para determinar os componentes de produção e qualidade dos frutos. O experimento foi conduzido em cinco ciclos. Os tratamentos consistiram de pessegueiro ‘BRS-Kampai’ autoenraizado ou enxertado em 17 porta-enxertos clonais de Prunus spp. As variáveis avaliadas foram produção por planta, produtividade por área, massa de frutos, diâmetro e firmeza de frutos, teor de sólidos solúveis, acidez titulável, volume de copa e eficiência produtiva. Em regiões subtropicais com invernos ‘Ishtara®’, ‘Genovesa’, ‘Santa Rosa’ e ‘Cadaman’ induziram baixa produtividade e baixa qualidade de frutos na ‘BRS-Kampai’ e não apresentam potencial para uso como porta-enxertos. ‘BRS-Kampai’ autoenraizadas ou enxertadas em ‘Flordaguard’ e ‘Okinawa’ são alternativas para o cultivo do pessegueiro, embora os sistemas de condução e poda devam ser ajustados devido ao alto vigor. Os porta-enxertos clonais ‘Tsukuba-3’ e ‘Tsukuba-2’ induziram o maior desempenho produtivo na ‘BRS-Kampai’, aliando qualidade de frutos, produtividade com maior estabilidade e eficiência produtiva tornando-os os mais indicados entre os porta-enxertos estudados.Título em português: Desempenho de porta-enxertos clonais para pessegueiro 'BRS-Kampai'e autoenraizado em região de inverno ameno

Heritability of peach tree resistance to bacterial leaf spot.

The objective of this work was to evaluate the broad-sense heritability reaction to bacterial leaf spot (Xanthomonas arboricola pv. pruni), in peach tree populations obtained from directed crosses. Disease severity and defoliation of the genotypes were evaluated in field conditions, with posterior measurement of the healthy leaf area duration (HAD). The observed average heritability (0.51) indicates that the use of the evaluated genitors can be effective for the development of cultivars with higher resistance to the disease.Notas Científicas. Título em português: Herdabilidade de resistência de pessegueiro à bacteriose foliar

Dependence of the energy resolution of a scintillating crystal on the readout integration time

The possibilty of performing high-rate calorimetry with a slow scintillating crystal is studied. In this experimental situation, to avoid pulse pile-up, it can be necessary to base the energy measurement on only a fraction of the emitted light, thus spoiling the energy resolution. This effect was experimentally studied with a BGO crystal and a photomultiplier followed by an integrator, by measuring the maximum amplitude of the signals. The experimental data show that the energy resolution is exclusively due to the statistical fluctuations of the number of photoelectrons contributing to the maximum amplitude. When such number is small its fluctuations are even smaller than those predicted by Poisson statistics. These results were confirmed by a Monte Carlo simulation which allows to estimate, in a general case, the energy resolution, given the total number of photoelectrons, the scintillation time and the integration time

eStroop: Implementation, Standardization, and Systematic Comparison of a New Voice-Key Version of the Traditional Stroop Task

The Stroop effect is a well-documented phenomenon, demonstrating both interference and facilitation effects. Many versions of the Stroop task were created, according to the purposes of its applications, varying in numerous aspects. While many versions are developed to investigate the mechanisms of the effect itself, the Stroop effect is also considered a general measure of attention, inhibitory control, and executive functions. In this paper, we implement “eStroop”: a new digital version based on verbal responses, measuring the main processes involved in the traditional effect. eStroop features four categories of stimuli in four different colors: (1) geometrical shapes, (2) neutral words, (3) congruent words, and (4) incongruent words. The results of the administration to 307 University students confirm the Stroop effect and offer baseline data for future research and clinical testing. Direct comparisons with other recent versions of the task are discussed, offering insights into differences and similarities between different task variables

Off-shell effects in dilepton production from hot interacting mesons

The production of dielectrons in reactions involving a_1 mesons and pions is studied. We compare results obtained with different phenomenological Lagrangians that have been used in connection with hadronic matter and finite nuclei. We insist on the necessity for those interactions to satisfy known empirical properties of the strong interaction. Large off-shell effects in dielectron production are found and some consequences for the interpretation of heavy ion data are outlined. We also compare with results obtained using experimentally-extracted spectral functions.Comment: 14 pages, LaTeX2e, 2 figure