491 research outputs found
The interaction in nuclear matter from a study of the reactions
The pion-production reactions were studied on
, , , and nuclei at an incident pion energy
of =283 MeV. Pions were detected in coincidence using the CHAOS
spectrometer. The experimental results are reduced to differential cross
sections and compared to both theoretical predictions and the reaction phase
space. The composite ratio between the
invariant masses on nuclei and on the nucleon is also presented. Near the
threshold pion pairs couple to when produced in
the reaction channel. There is a marked near-threshold
enhancement of which is consistent with theoretical
predictions addressing the partial restoration of chiral symmetry in nuclear
matter. Furthermore, the behaviour of is well
described when the restoration of chiral symmetry is combined with standard
P-wave renormalization of pions in nuclear matter. On the other hand, nuclear
matter only weakly influences , which displays a flat
behaviour throughout the energy range regardless of .Comment: 30 pages, 16 figures, PS format, accepted for publication in Nucl.
Phys
An innovation for organic crop production by compost fertilizer of Isfahan municipal’s waste as bionematicide and biofertilizer
Sugar beet cyst nematode (SBCN), Hederodera schachtii Schmidt. 1871, marked as one of the most damaging disease of sugar beet fields worldwide. Non chemical controls measures were carried out, using organic fertilizers including farm, poultry and green manure (waste cabbage leaves), compost (municipal’s waste products, 0.15 and 0.08 mm in size) and vermicomposting as the soil treatments at various rates against control (no treatments) in glass house and field highly infested with the nematode, SBCN in Isfahan, Iran. The related data on cysts final population, number of eggs and second larvae per cyst and per gram of soil were subjected to statistical analysis. The reproduction factor and the percent reduction and or increasing in population of nematode, SBCN were taken into consideration in comparison to initial populations. The results revealed that, poultry manure at the rate of 40 t ha-1 had the most and highly significant effects on the final population reduction in contrast to other ones, including controls. Followed by 0.15mm (60 t ha-1), compost 0.08 (60 t ha-1), poultry manure at the rate of 20 t ha-1, with no significant differences respectively. Vermicomposting, cabbage leaves and form manure treatments had the least effects on the final population reduction in sugar beet cyst nematode populations.Keywords: compost municipality wastes, cyst nematodes, organic matters, Isfahan, Ira
Adenome pleomorphe des glandes salivaires accessoires
Objective : Pleomorphic adenoma (PA) is the most common benign neoplasm of the minor salivary glands. Clinical behavior,diagnosis, treatment modalities and evolution of nine cases of pleomorphic adenoma were discussed.Materials and methods : This is a descriptive and retrospective study about 9 cases of pleomorphic adenoma conductedover a period of 20 years (1990 Ã 2009) at the ENT department of Sousse (Tunisia).Results : There were 5 men and 4 women having a mean age of 40 years. The main site of this adenoma was the hard palate. The others 3 tumors were seen in the nasal cavity, in the parapharyngeal space and in cervical soft tissues. Clinical examination showed a swelling at the level of the interested region. Computed tomography (CT) was made in 5 cases,associated to the magnetic resonance imaging (MRI) in 2 cases. The treatment was based in surgical excision of the tumors. Histologically, the tumor showed features of a benign PA in 8 cases and of malignant PA in 1 case. Two patients had a documented local recurrence. The evolution was good for the first patient after secondary excision of the tumor.The patient presenting a carcinoma ex pleomorphic adenoma developed quickly pulmonary and cerebral metastases.Conclusion : Pleomorphic adenoma of minor salivary gland is generally known to be a slow-growing tumour. They must be evoked before all painless swelling in the upper aerodigestive tract developed under a healthy mucosa. The surgical management is basically total resection of the tumor with a safety margin of 5 mm. Longer follow-up was needed due to the possibility of recurrences and malignancy transformation.Keywords : Pleomorphic adenoma, Minor salivary gland, Imaging
The pi -> pi pi process in nuclei and the restoration of chiral symmetry
The results of an extensive campaign of measurements of the pi -> pi pi
process in the nucleon and nuclei at intermediate energies are presented. The
measurements were motivated by the study of strong pi pi correlations in
nuclei. The analysis relies on the composite ratio C_{pi pi}^A, which accounts
for the clear effect of the nuclear medium on the (pi pi) system. The
comparison of the C_{pi pi}^A distributions for the (pi pi)_{I=J=0} and (pi
pi)_{I=0,J=2} systems to the model predictions indicates that the C_{pi pi}^A
behavior in proximity of the 2m_pi threshold is explainable through the partial
restoration of chiral symmetry in nuclei.Comment: accepted for publication in Nucl. Phys.
Sputum macrophage diversity and activation in asthma: role of severity and inflammatory phenotype
BACKGROUND:Macrophages control innate and acquired immunity, but their role in severe asthma remains ill-defined. We investigated gene signatures of macrophage subtypes in the sputum of 104 asthmatics and 16 healthy volunteers from the U-BIOPRED cohort. METHODS:Forty-nine gene signatures (modules) for differentially stimulated macrophages, one to assess lung tissue-resident cells (TR-Mφ) and two for their polarization (classically and alternatively activated macrophages: M1 and M2, respectively) were studied using gene set variation analysis. We calculated enrichment scores (ES) across severity and previously identified asthma transcriptome-associated clusters (TACs). RESULTS:Macrophage numbers were significantly decreased in severe asthma compared to mild-moderate asthma and healthy volunteers. The ES for most modules were also significantly reduced in severe asthma except for 3 associated with inflammatory responses driven by TNF and Toll-like receptors via NF-κB, eicosanoid biosynthesis via the lipoxygenase pathway and IL-2 biosynthesis (all P < .01). Sputum macrophage number and the ES for most macrophage signatures were higher in the TAC3 group compared to TAC1 and TAC2 asthmatics. However, a high enrichment was found in TAC1 for 3 modules showing inflammatory pathways linked to Toll-like and TNF receptor activation and arachidonic acid metabolism (P < .001) and in TAC2 for the inflammasome and interferon signalling pathways (P < .001). Data were validated in the ADEPT cohort. Module analysis provides additional information compared to conventional M1 and M2 classification. TR-Mφ were enriched in TAC3 and associated with mitochondrial function. CONCLUSIONS:Macrophage activation is attenuated in severe granulocytic asthma highlighting defective innate immunity except for specific subsets characterized by distinct inflammatory pathways
Comparison of Engineering Wake Models with CFD Simulations
The engineering wake models by Jensen [1] and Frandsen et al. [2] are assessed for different scenarios simulated using Large Eddy Simulation and the Actuator Line method implemented in the Navier-Stokes equations. The scenarios include the far wake behind a single wind turbine, a long row of turbines in an atmospheric boundary layer, idealised cases of an infinitely long row of wind turbines and infinite wind farms with three different spacings. Both models include a wake expansion factor, which is calibrated to fit the simulated wake velocities. The analysis highlights physical deficiencies in the ability of the models to universally predict the wake velocities, as the expansion factor can be fitted for a given case, but with not apparent transition between the cases. 1
SG-VAE: Scene Grammar Variational Autoencoder to generate new indoor scenes
Deep generative models have been used in recent years to learn coherent
latent representations in order to synthesize high-quality images. In this
work, we propose a neural network to learn a generative model for sampling
consistent indoor scene layouts. Our method learns the co-occurrences, and
appearance parameters such as shape and pose, for different objects categories
through a grammar-based auto-encoder, resulting in a compact and accurate
representation for scene layouts. In contrast to existing grammar-based methods
with a user-specified grammar, we construct the grammar automatically by
extracting a set of production rules on reasoning about object co-occurrences
in training data. The extracted grammar is able to represent a scene by an
augmented parse tree. The proposed auto-encoder encodes these parse trees to a
latent code, and decodes the latent code to a parse tree, thereby ensuring the
generated scene is always valid. We experimentally demonstrate that the
proposed auto-encoder learns not only to generate valid scenes (i.e. the
arrangements and appearances of objects), but it also learns coherent latent
representations where nearby latent samples decode to similar scene outputs.
The obtained generative model is applicable to several computer vision tasks
such as 3D pose and layout estimation from RGB-D data
SG-VAE: Scene Grammar Variational Autoencoder to Generate New Indoor Scenes
Deep generative models have been used in recent years to learn coherent latent representations in order to synthesize high-quality images. In this work, we propose a neural network to learn a generative model for sampling consistent indoor scene layouts. Our method learns the co-occurrences, and appearance parameters such as shape and pose, for different objects categories through a grammar-based auto-encoder, resulting in a compact and accurate representation for scene layouts. In contrast to existing grammar-based methods with a user-specified grammar, we construct the grammar automatically by extracting a set of production rules on reasoning about object co-occurrences in training data. The extracted grammar is able to represent a scene by an augmented parse tree. The proposed auto-encoder encodes these parse trees to a latent code, and decodes the latent code to a parse tree, thereby ensuring the generated scene is always valid. We experimentally demonstrate that the proposed auto-encoder learns not only to generate valid scenes (i.e. the arrangements and appearances of objects), but it also learns coherent latent representations where nearby latent samples decode to similar scene outputs. The obtained generative model is applicable to several computer vision tasks such as 3D pose and layout estimation from RGB-D data
Quark mass dependence of the nucleon axial-vector coupling constant
We study the quark mass expansion of the axial-vector coupling constant g_A
of the nucleon. The aim is to explore the feasibility of chiral effective field
theory methods for extrapolation of lattice QCD results - so far determined at
relatively large quark masses corresponding to pion masses larger than 0.6 GeV
- down to the physical value of the pion mass. We compare two versions of
non-relativistic chiral effective field theory: One scheme restricted to pion
and nucleon degrees of freedom only, and an alternative approach which
incorporates explicit Delta(1230) resonance degrees of freedom. It turns out
that, in order to approach the physical value of g_A in a leading-one-loop
calculation, the inclusion of the explicit Delta(1230) degrees of freedom is
crucial. With information on important higher order couplings constrained from
analyses of inelastic pion production processes, a chiral extrapolation
function for g_A is obtained, which works well from the chiral limit across the
physical point into the region of present lattice data. The resulting
enhancement of our extrapolation function near the physical pion mass is found
to arise from an interplay between long- and short- distance physics.Comment: 21 pages, LaTeX, 7 figure
General properties of the pion production reaction in nuclear matter
The pion production reaction on was
studied at incident pion energies of = 240, 260, 280, 300, and
320 MeV. The experiment was performed using the pion-channel at TRIUMF,
and multiparticle events, () and
(), were detected with the CHAOS spectrometer. Results
are reported in the form of both differential and total cross sections, and are
compared to theoretical predictions and the reaction phase space. The present
investigation of the T-dependence of the
reaction complements earlier examinations of the A-dependence of the reaction,
which was measured using , , , , , and
targets at 280 MeV. Some general properties of the
pion-induced pion production reaction in nuclear matter will be presented,
based on the combined results of the two studies.Comment: 23 pages, Latex, accepted for publication in Nucl. Phys.
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