A
bstract
A comprehensive set of azimuthal single-spin and double-spin asymmetries in semi-inclusive leptoproduction of pions, charged kaons, protons, and antiprotons from transversely polarized ...protons is presented. These asymmetries include the previously published HERMES results on Collins and Sivers asymmetries, the analysis of which has been extended to include protons and antiprotons and also to an extraction in a three-dimensional kinematic binning and enlarged phase space. They are complemented by corresponding results for the remaining four single-spin and four double-spin asymmetries allowed in the one-photon-exchange approximation of the semi-inclusive deep-inelastic scattering process for target-polarization orientation perpendicular to the direction of the incoming lepton beam. Among those results, significant non-vanishing cos (
ϕ−ϕ
S
) modulations provide evidence for a sizable worm-gear (II) distribution,
g
1
T
q
x
p
T
2
. Most of the other modulations are found to be consistent with zero with the notable exception of large sin (
ϕ
S
) modulations for charged pions and
K
+
.
A comprehensive collection of results on longitudinal double-spin asymmetries is presented for charged pions and kaons produced in semi-inclusive deep-inelastic scattering of electrons and positrons ...on the proton and deuteron, based on the full HERMES data set. The dependence of the asymmetries on hadron transverse momentum and azimuthal angle extends the sensitivity to the flavor structure of the nucleon beyond the distribution functions accessible in the collinear framework. No strong dependence on those variables is observed. In addition, the hadron charge-difference asymmetry is presented, which under certain model assumptions provides access to the helicity distributions of valence quarks.
A survey was conducted on two Brazilian chocolate manufacturing companies (A and B) to investigate/determine Enterobacteriaceae, coliforms and Salmonella contamination. Samples of different chocolate ...types, processed cocoa-based ingredients, manufacturing environment, and workers' hand surfaces were analyzed. Salmonella and Escherichia coli were not detected. However, in 25.8% of the chocolate samples, Enterobacteriaceae were isolated while total coliforms were detected in 13.3%. Among the processed cocoa-based ingredients, two samples of cocoa liquor showed contamination by Enterobacteriaceae and total coliforms, and in one sample thermotolerant coliforms were also recovered. For equipment and utensils, Enterobacteriaceae were isolated in around 25.4% of the samples, whereas total coliforms were detected in 10.2%. Moreover, in company A 14.3% of manufacturing environment samples were contaminated by thermotolerant coliforms. The food handlers from both companies showed a high percentage of Enterobacteriaceae contamination on their hands. The results showed that the manufacturing environment including food handlers was considered the most likely Enterobacteriaceae contamination source of the finished product. These data also highlight Enterobacteriaceae as a good hygiene indicator for the chocolate industry.
•Identification of the Enterobacteriaceae contamination source in chocolate.•Cocoa-based ingredients were not a significant contamination source in chocolate.•Processing environment was the most likely Enterobacteriaceae source in chocolate.
Abstract The non-competitive N-methyl- d -aspartate (NMDA) glutamate receptor antagonist ketamine has been shown to produce cognitive deficits. However, the effects of ketamine on the consolidation ...phase of memory remain poorly characterized. Here we show that systemic administration of ketamine immediately after training dose-dependently impairs long-term retention of memory for a novel object recognition (NOR) task in rats. Control experiments showed that the impairing effects of ketamine could not be attributed to an influence on memory retrieval or sensorimotor effects. In addition, ketamine prevented the increase in hippocampal brain-derived neurotrophic factor (BDNF) levels induced by NOR learning. Our results show for the first time that ketamine disrupts the consolidation phase of long-term recognition memory. In addition, the findings suggest that the amnestic effects of ketamine might be at least partially mediated by an influence on BDNF signaling in the hippocampus.
Histone acetylation is a chromatin modification critically involved in gene regulation during many neural processes. The enzymes that regulate levels of histone acetylation are histone ...acetyltransferases (HATs), which activate gene expression and histone deacetylases (HDACs), that repress gene expression. Acetylation together with other histone and DNA modifications regulate transcription profiles for specific cellular functions. Our previous research has demonstrated a pivotal role for cyclicAMP response element binding protein (CREB)-binding protein (CBP), a histone acetyltransferase, in long-term memory for novel object recognition (NOR). In fact, every genetically modifiedCbp mutant mouse characterized thus far exhibits impaired long-term memory for NOR. These results suggest that long-term memory for NOR is especially sensitive to alterations in CBP activity. Thus, in the current study, we examined the role of HDACs in memory for NOR. We found that inducing a histone hyperacetylated state via HDAC inhibition transforms a learning event that would not normally result in long-term memory into an event that is now remembered long-term. We have also found that HDAC inhibition generates a type of long-term memory that persists beyond a point at which normal memory for NOR fails. This result is particularly interesting because one alluring aspect of examining the role of chromatin modifications in modulating transcription required for long-term memory processes is that these modifications may provide potentially stable epigenetic markers in the service of activating and/or maintaining transcriptional processes.
Double-spin asymmetries in exclusive electroproduction of real photons from a transversely polarized hydrogen target are measured with respect to the product of target polarization with beam helicity ...and beam charge, and with respect to the product of target polarization with beam helicity alone. The asymmetries arise from the deeply virtual Compton scattering process and its interference with the Bethe–Heitler process. They are related to the real part of the same combination of Compton form factors as that determining the previously published transverse target single-spin asymmetries through the imaginary part. The results for the double-spin asymmetries are found to be compatible with zero within the uncertainties of the measurement, and are not incompatible with the predictions of the only available GPD-based calculation.
Azimuthal single-spin asymmetries of leptoproduced pions and charged kaons were measured on a transversely polarized hydrogen target. Evidence for a naive-T-odd, transverse-momentum-dependent parton ...distribution function is deduced from nonvanishing Sivers effects for pi(+), pi(0), and K(+/-), as well as in the difference of the pi(+) and pi(-) cross sections.
A thin film-based solid oxide fuel cell is deposited on a Ni-based metal porous support by pulsed laser deposition with a multi-scale-graded microstructure design. The fuel cell, around 1 μm in ...thickness, is composed of a stabilized-zirconia/doped-ceria bi-layered dense electrolyte and nanostructured Ni-stabilized zirconia and La
0.6
Sr
0.4
CoO
3
electrodes as the anode and cathode, respectively. The cell is tested at intermediate temperatures (600-650 °C) with the aim to discern the degradation mechanisms occurring in the cell under accelerated conditions. Under open circuit conditions, electrochemical performances are steady, indicating the stability of the cell. Under electrical load, a progressive degradation is activated. Post-test analysis reveals both mechanical and chemical degradation of the cell. Cracks and delamination of the thin films promote a significant nickel diffusion and new phase formation. Signs of elemental distribution at low temperature are detected throughout the cell, indicating a combination of low energy surface elemental interdiffusion and electromigration effects.
Elemental distribution effects are detected throughout the metal supported TF-SOFC, indicating low energy surface elemental interdiffusion and electromigration effects.
Evidence for a narrow baryon state is found in quasi-real photoproduction on a deuterium target through the decay channel pK0S→pπ+π−. A peak is observed in the pK0S invariant mass spectrum at ...1528±2.6(stat)±2.1(syst) MeV. Depending on the background model, the naive statistical significance of the peak is 4–6 standard deviations and its width may be somewhat larger than the experimental resolution of σ=4.3–6.2 MeV. This state may be interpreted as the predicted S=+1 exotic Θ+(uudds̄) pentaquark baryon. No signal for an hypothetical Θ++ baryon was observed in the pK+ invariant mass distribution. The absence of such a signal indicates that an isotensor Θ is excluded and an isovector Θ is unlikely.
Bose–Einstein correlations of like-sign charged hadrons produced in deep-inelastic electron and positron scattering are studied in the HERMES experiment using nuclear targets of
1
H,
2
H,
3
He,
4
He, ...N, Ne, Kr, and Xe. A Gaussian approach is used to parametrize a two-particle correlation function determined from events with at least two charged hadrons of the same sign charge. This correlation function is compared to two different empirical distributions that do not include the Bose–Einstein correlations. One distribution is derived from unlike-sign hadron pairs, and the second is derived from mixing like-sign pairs from different events. The extraction procedure used simulations incorporating the experimental setup in order to correct the results for spectrometer acceptance effects, and was tested using the distribution of unlike-sign hadron pairs. Clear signals of Bose–Einstein correlations for all target nuclei without a significant variation with the nuclear target mass are found. Also, no evidence for a dependence on the invariant mass
W
of the photon-nucleon system is found when the results are compared to those of previous experiments.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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