3,655 research outputs found
Particle yields in heavy ion collisions and the influence of strong magnetic fields
It is expected that the magnetic field in the surface of magnetars do not
exceed G. However, in heavy ion collisions, this value is expected to
be much higher. We investigate the effects of a magnetic fields varying from
, to G in strange matter (composed of , and
quarks). We model matter as a free gas of baryons and mesons under the
influence of an external magnetic field. We study the effects of such strong
fields through a fit to some data sets of the STAR experiment. For
this purpose we solve the Dirac, Rarita-Schwinger, Klein-Gordon and Proca
equations subject to magnetic fields in order to obtain the energy expressions
and the degeneracy for spin 1/2, spin 3/2, spin 0 and spin 1 particles,
respectively. Our results show that a field of the order of G
produces an improved fitting to the experimental data as compared to the
calculations without magnetic field.Comment: 20 pages, 16 figures, 4 table
Landau parameters for isospin asymmetric nuclear matter based on a relativistic model of composite and finite extension nucleons
We study the properties of cold asymmetric nuclear matter at high density,
applying the quark meson coupling model with excluded volume corrections in the
framework of the Landau theory of relativistic Fermi liquids. We discuss the
role of the finite spatial extension of composite baryons on dynamical and
statistical properties such as the Landau parameters, the compressibility, and
the symmetry energy. We have also calculated the low lying collective
eigenfrequencies arising from the collisionless quasiparticle transport
equation, considering both unstable and stable modes. An overall analysis of
the excluded volume correlations on the collective properties is performed.Comment: 24 pages, 6 figure
The Cramer-Rao Bound and DMT Signal Optimisation for the Identification of a Wiener-Type Model
In linear system identification, optimal excitation signals can be determined using the Cramer-Rao bound. This problem has not been thoroughly studied for the nonlinear case. In this work, the Cramer-Rao bound for a factorisable Volterra model is derived. The analytical result is supported with simulation examples. The bound is then used to find the optimal excitation signal out of the class of discrete multitone signals. As the model is nonlinear in the parameters, the bound depends on the model parameters themselves. On this basis, a three-step identification procedure is proposed. To illustrate the procedure, signal optimisation is explicitly performed for a third-order nonlinear model. Methods of nonlinear optimisation are applied for the parameter estimation of the model. As a baseline, the problem of optimal discrete multitone signals for linear FIR filter estimation is reviewed
Participatory design, beyond the local
This workshop aims at stimulating and opening a debate around the capacity of Participatory Design (PD) and other co-design approaches to deliver outcomes and methodologies that can have an impact and value for reuse well beyond the local context in which they were originally developed. This will be achieved by stimulating the submission of position papers by researchers from the PD community and beyond.These papers will be discussed during the workshop in order to identify challenges, obstacles but also potentials for scaling up PD processes and results from the local to the global.</p
Footprints of element mobility during metasomatism linked to a late Miocene peraluminous granite intruding a carbonate host (Campiglia Marittima, Tuscany)
The Campiglia Marittima magmatic-hydrothermal system includes a peraluminous granite, its carbonatic host, and skarn. The system evolved generating a time-transgressive exchange of major and trace elements between granite, metasomatic fluids, and host rock. The process resulted in partial metasomatic replacement of the granite and severe replacement of the carbonate host rocks. The fluid activity started during a late-magmatic stage, followed by a potassic–calcic metasomatism, ending with a lower temperature acidic metasomatism. During the late-magmatic stage, B-rich residual fluids led to the formation of disseminated tourmaline–quartz orbicules. High-temperature metasomatic fluids generated a pervasive potassic–calcic metasomatism of the granite, with replacement of plagioclase, biotite, ilmenite, and apatite by K-feldspar, phlogopite–chlorite–titanite, titanite–rutile, and significant mobilization of Fe, Na, P, Ti, and minor HFSE/REE. The metasomatized granite is enriched in Mg, K, Rb, Ba, and Sr, and depleted in Fe and Na. Ca metasomatism is characterized by crystallization of a variety of calc-silicates, focusing along joints into the granite (endoskarn) and at the marble/pluton contact (exoskarn), and exchange of HFSE and LREE with hydrothermal fluids. Upon cooling, fluids became more acidic and fluorine activity increased, with widespread crystallization of fluorite from disequilibrium of former calc-silicates. At the pluton-host boundary, fluids were accumulated, and pH buffered to low values as temperature decreased, leading to the formation of a metasomatic front triggering the increasing mobilization of REE and HFSE and the late crystallization of REE–HFSE minerals
Quantitative risk assessment: an emerging tool for emerging foodborne pathogens.
New challenges to the safety of the food supply require new strategies for evaluating and managing food safety risks. Changes in pathogens, food preparation, distribution, and consumption, and population immunity have the potential to adversely affect human health. Risk assessment offers a framework for predicting the impact of changes and trends on the provision of safe food. Risk assessment models facilitate the evaluation of active or passive changes in how foods are produced, processed, distributed, and consumed
Testicular cancer and sperm DNA damage: short- and long-term effects of antineoplastic treatment
The aim of this study was to investigate sperm DNA damage induced by chemo- and radiotherapy in patients with testicular cancer to provide data on the extent and persistence of nuclear damage that might affect individual reproductive potential. We evaluated pre- and post-antineoplastic treatment sperm DNA integrity, expressed as DNA Fragmentation Index (DFI), in a large caseload of testicular cancer patients by sperm chromatin structure assay. The mean total DFI for all patients at T0 was 18.0 ± 12.5%. Sperm chromatin profile was markedly impaired at T3 (27.7 ± 17.4%) and T6 (23.2 ± 15.3%), improving considerably at T12 and T24 (14.0 ± 8.9% and 14.4 ± 10.3%). After chemotherapy, we found a marked increase in DFI at T3 and T6 and a significant reduction at T12 and T24 in comparison with the baseline. In contrast, DFI increased at T3 and T6 after radiotherapy but the subsequent reduction was far less marked, reaching baseline values at T12 and T24. Finally, post-treatment DNA damage was not age or histotype dependent, but was more marked in the advanced stage of cancer. In this study, we showed that the chromatin profile may be affected in the months immediately following the end of the treatment, improving after 12-24 months. Our results thus indicate that post-treatment DNA damage is influenced both by the type and intensity of the therapy and by the pathological and clinical stage of the disease. © 2014 American Society of Andrology and European Academy of Andrology
Self-DNA Early Exposure in Cultivated and Weedy Setaria Triggers ROS Degradation Signaling Pathways and Root Growth Inhibition
The accumulation of fragmented extracellular DNA reduces conspecific seed germination and plantlet growth in a concentration-dependent manner. This self-DNA inhibition was repeatedly reported, but the underlying mechanisms are not fully clarified. We investigated the species-specificity of self-DNA inhibition in cultivated vs. weed congeneric species (respectively, Setaria italica and S. pumila) and carried out a targeted real-time qPCR analysis under the hypothesis that self-DNA elicits molecular pathways that are responsive to abiotic stressors. The results of a cross-factorial experiment on root elongation of seedlings exposed to self-DNA, congeneric DNA, and heterospecific DNA from Brassica napus and Salmon salar confirmed a significantly higher inhibition by self-DNA as compared to non-self-treatments, with the latter showing a magnitude of the effect consistent with the phylogenetic distance between the DNA source and the target species. Targeted gene expression analysis highlighted an early activation of genes involved in ROS degradation and management (FSD2, ALDH22A1, CSD3, MPK17), as well as deactivation of scaffolding molecules acting as negative regulators of stress signaling pathways (WD40-155). While being the first exploration of early response to self-DNA inhibition at molecular level on C4 model plants, our study highlights the need for further investigation of the relationships between DNA exposure and stress signaling pathways by discussing potential applications for species-specific weed control in agriculture
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